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Patient: Female, 7-year-old Final Diagnosis: Necrotic pulp and asymptomatic apical periodontitis Symptoms: No symptoms • asymptomatic Clinical Procedure: Regenerative endodontic procedure Specialty: Dentistry Objective: Unusual or unexpected effect of treatment Background: The regenerative endodontic procedure (REP) for managing necrotic immature permanent teeth has the advantage of promoting root growth over the traditionally used apexification techniques. However, there is limited evidence on the long-term outcome of standardized REPs performed on immature molars. This case report presents the 5-year clinical and radiographic outcomes of REP performed on an immature mandibular first molar. Case Report: A healthy 7-year-old girl with a carious right mandibular first molar was referred to the endodontic clinic for evaluation and treatment. Clinical examination showed large occlusal caries, no tenderness to palpation and percussion tests, and no response to cold and electric pulp tests. Radiographic examination showed deep caries, apical radiolucency related to the open apices, and wide root canal space. Accordingly, the tooth was diagnosed with necrotic pulp and asymptomatic apical periodontitis. The REP was performed following the American Association of Endodontics guidelines, which comprise minimal instrumentation, disinfection with sodium hypochlorite irrigant, use of triple antibiotic paste, induced intracanal bleeding, and application of a coronal mineral trioxide aggregate plug. The patient missed the scheduled follow-up appointments but presented at the clinic 5 years later with an asymptomatic tooth. Clinical and radiographic examination revealed no tenderness to percussion and palpation test, no response to cold test, positive response to electric pulp test, apical healing, apical closure, root lengthening, and canal wall thickening and calcification. Conclusions: While true pulp regeneration is unachievable, the REP, following the current protocol, is clinically successful in achieving root maturation and tooth retention. [ABSTRACT FROM AUTHOR]

Fibroblast growth factor (FGF) signalling plays a crucial role in the morphogenesis of multiple tissues including teeth. While the role of the signal has been studied in tooth crown development, little is known about root development. Of several FGF ligands involved in hard tissue formation, we suggest that FGF18 regulates the development of murine tooth roots. We implanted FGF18‐soaked heparin beads into the lower first molar tooth buds at postnatal day 6 (P6), followed by transplantation under the kidney capsule. After 3 weeks, FGF18 significantly facilitated root elongation and periodontal tissue formation compared to the control. In situ hybridisation showed that Fgf18 transcripts were initially localised in the dental pulp along Hertwig's epithelial root sheath at P6 and P10 and subsequently in the dental follicle cells at P14. Fgf receptors were expressed in various dental tissues during these stages. In vitro analysis using the dental pulp stem cells revealed that FGF18 inhibited cell proliferation and decreased expression levels of osteogenic markers, Runx2, Alpl and Sp7. Consistently, after 1 week of kidney capsule transplantation, FGF18 application did not induce the expression of Sp7 and Bsp, but upregulated Periostin in the apical region of dental mesenchyme in the grafted molar. These findings suggest that FGF18 facilitates molar root development by regulating the calcification of periodontal tissues. [ABSTRACT FROM AUTHOR]

Manufacturing internal splines with complex structures in high-hardness materials poses challenges in conventional machining processes. This paper introduced a new electrochemical machining (ECM) method using an assembled tool cathode with a cathode working teeth sheet with circumferential vibration for efficient and stable shaping of involute internal splines of intricate high-hardness components. A detailed design of the assembled tool cathode is presented, accompanied by flow field simulations analysing electrolyte distribution during circumferential vibration. A specific experimental system, fixture, and a used electrolyte filter module were constructed for spline ECM experiments. The results show that with the cathode feed rate of 2.7 mm/min, and the circumferential vibration frequency of 80 Hz, the involute internal spline profiles were successfully shaped with higher precision and efficiency with less appropriate allowance. • A novel ECM approach featuring an assembled tool cathode, equipped with teeth that vibrate circumferentially, is introduced for enhanced machining. • Circumferential vibration of the cathode is shown to improve electrolyte distribution in the area where tooth roots are machined, facilitating better machining outcomes. • An experimental ECM system for spline machining, complete with a dedicated fixture and a module for filtering used electrolyte, has been developed. • Utilizing a cathode feed rate of 2.7 mm/min and a vibration frequency of 80 Hz, precise involute internal spline profiles are achieved with minimized excess material. [ABSTRACT FROM AUTHOR]

Aim: Previous endodontic research has provided limited understanding of the prevalence and roles of haemolytic and non‐haemolytic Enterococcus faecalis strains in root filled teeth. This study aimed to determine the prevalence of these strains in root filled teeth with periradicular lesions and investigate their associated virulence factors. Methodology: A total of 36 root canal samples were collected from 36 subjects. The prevalence of E. faecalis was determined using culture and PCR methods. Antibiotic susceptibility of haemolytic and non‐haemolytic E. faecalis strains was assessed using the broth dilution assay. The cytokine stimulation in periodontal ligament (PDL) cells and neutrophil migration were evaluated using real‐time PCR and migration assay, respectively. Cell invasion ability of the strains was assessed using a cell culture model. Additionally, the virulence gene expression of the haemolytic and non‐haemolytic strains was investigated using real‐time PCR. The Mann–Whitney U and Spearman's ρ tests were used to examine the significant difference between the two strains and to analyse the correlation between phenotype and gene expression, respectively. Results: Enterococcus faecalis was detected in 33.3% and 88.9% of samples by culture and real‐time PCR, respectively. Haemolytic strains were found in 36.4% of subjects. Non‐haemolytic strains exhibited susceptibility to erythromycin and varying susceptibility to tetracycline, while all haemolytic strains were resistant to both antibiotics. Haemolytic strains significantly upregulated the expression of IL‐8, OPG and RANKL in PDL cells (p <.05). Notably, the fold increases in these genes were higher: IL‐8 (556.1 ± 82.9 vs. 249.6 ± 81.8), OPG (2.2 ± 0.5 vs. 1.3 ± 0.2) and RANKL (1.8 ± 0.3 vs. 1.2 ± 0.1). Furthermore, haemolytic strains had a greater effect on neutrophil migration (68.7 ± 15.2% vs. 46.9 ± 11.4%) and demonstrated a higher level of internalization into oral keratinocyte cells (68.6 ± 0.4% vs. 33.8 ± 0.5%) (p <.05). They also showed enhanced expression of virulence genes associated with haemolysin, surface proteins, collagen‐binding and aggregation substances. Gelatinase activity was only detectable in non‐haemolytic strains. Conclusions: This study revealed that haemolytic strains E. faecalis possessed enhanced abilities in host invasion and a higher abundance of virulence factors, suggesting their potential contribution to more severe disease manifestations. [ABSTRACT FROM AUTHOR]

Aim: To evaluate the indication of the endodontic treatment for vital intact teeth with the root apex involved in large radicular cystic lesions of endodontic origin. Methodology: This prospective cohort study enrolled healthy participants with radicular cysts of endodontic origin and with the root apex of vital intact teeth involved in the bone defect, as determined by cone beam computed tomography (CBCT). Thirty‐two sound vital teeth were analysed by thermal (TPT) and electric pulp tests (EPT) before surgery (T0) and 1 week (T1), 2 weeks (T2), 3 months (T3) and 6 months (T4) post‐surgery. Student's t‐test (p <.05) was used to compare the EPT values at baseline and T4. anova (p <.05) was used to analyse the EPT variations for all maxillary and mandibular teeth. McNemar test (p <.05) was used to compare the results according to variation in EPT values gathering by variation, no variation and no response. Results: At T1, 75 and 65.7% of teeth responded positively whilst 25 and 34.3% did not respond to EPT and TPT, respectively. The variation of the EPT values between T0 and T1 was observed for 50.0% of teeth, whilst no variation was noticed in 25.0% of teeth. At T4, 90.6 and 87.5% of teeth responded positively whilst 9.4 and 12.5% did not respond to EPT and TPT, respectively. At T4, variation of the EPT values between T0 and T4 was observed for 28.1%, whilst no variation was noticed in 62.5% of teeth. There were no statistical differences in EPT results between T0 and T4 (p >.05), but significant differences were observed for EPT values between T1 and T4 (p <.05), and between mandibular and maxillary teeth. The pulp sensibility of maxillary teeth worsened after surgery, before reverting progressively to T0 values, whilst no statistically significant differences were observed for mandibular teeth at the different time points. Conclusions: These data support the inconsistence of the prophylactic endodontic treatment in healthy vital teeth with apex involvement in large cystic lesions of endodontic origin. Post‐surgery follow‐up with TPT and EPT is recommended to assess pulp status. [ABSTRACT FROM AUTHOR]

Background/Aims: Dental trauma resulting in tooth intrusion is a severe injury of permanent dentition, with a prevalence of 0.5%–1.9% among traumatic dental injuries. Currently, treatment guidelines for intruded permanent teeth depend on root development and the degree of intrusion. However, the categorization of tooth maturity as mature or immature simplifies a complex continuum of root development stages. This study aims to investigate the impact of various stages of root development on the success of spontaneous re‐eruption (SRE) of intruded teeth. Materials and Methods: This retrospective study analysed data from 80 children (125 teeth) aged 6–12 years who experienced dental intrusion between 2018 and 2022. Root maturation was classified based on Cvek's classification, eight were categorized as stage 1, 29 as stage 2, 44 as stage 3, 25 as stage 4, and 19 as stage 5. Intruded teeth with immature roots (Cvek's class 1–4) underwent SRE, while mature teeth (Cvek's class 5) were treated with SRE, orthodontic repositioning, or surgical repositioning based on the degree of intrusion. Primary outcome measures were successful re‐eruption and secondary outcomes included observed complications during follow‐up. Results: Regression analysis revealed that the patient's age, degree of root maturation, and degree of intrusion significantly affected spontaneous re‐eruption (p <.05). SRE was more successful in teeth with Cvek's stages 1 and 2 compared to stages 3 and 4. Complications were associated with the treatment method, degree of root immaturity, and degree of intrusion. Conclusion: The study demonstrates that as root maturation progresses, the likelihood of re‐eruption decreases, and the risk of pulp necrosis and infection increases. Therefore, teeth in later stages of immaturity (Cvek stage 4) should be repositioned orthodontically or surgically without waiting for spontaneous re‐eruption. [ABSTRACT FROM AUTHOR]

Objective: The aim of the present pilot study was to assess the effectiveness of the platelet-rich fibrin (PRF) apical barrier for the placement of MTA for the treatment of teeth with periapical lesions and open apices. Methods: A total of thirty teeth on twenty-eight patients with open apices and periapical periodontitis were enrolled and divided into two groups in the present pilot study. In the PRF group (fourteen teeth in thirteen patients), nonsurgical endodontic treatment was performed using PRF as an apical matrix, after which the apical plug of the MTA was created. For the non-PRF group (fourteen teeth in fourteen patients), nonsurgical endodontic therapy was performed using only the MTA for an apical plug with no further periapical intervention. Clinical findings and periapical digital radiographs were used for evaluating the healing progress after periodic follow-ups of 1, 3, 6, and 9 months. The horizontal dimension of the periapical lesion was gauged, and the changes in the dimensions were recorded each time. The Friedman test, Dunn-Bonferroni post hoc correction, and Mann-Whitney U test were used for statistical analysis, with P < 0.05 serving as the threshold for determining statistical significance. Results: All patients in both groups in the present pilot study had no clinical symptoms after 1 month, with a significant reduction in the periapical lesion after periodic appointments. The lesion width of the PRF group was significantly smaller than that of the non-PRF group in the sixth and ninth month after treatment. Conclusions: PRF is a promising apical barrier matrix when combined with MTA for the treatment of teeth with open apices and periapical periodontitis. Small number of study subjects and the short time of follow-up period limit the generalizability of these results. Trial registration: TCTR, TCTR20221109006. Registered 09 November 2022 - Retrospectively registered, https://www.thaiclinicaltrials.org/show/TCTR20221109006. [ABSTRACT FROM AUTHOR]

BACKGROUND: There is an increasing demand for orthodontic treatment, and periodontally accelerated osteogenic orthodontics (PAOO) technique can make it possible to move orthodontic teeth that are limited by thin alveolar bone. OBJECTIVE: To investigate the biomechanics of orthodontic tooth movement before and after periodontally accelerated osteogenic orthodontics (PAOO) surgery to increase alveolar bone volume using the three-dimensional finite element method. METHODS: A patient undergoing PAOO surgery before orthodontic treatment to increase bone volume on the labial side of the mandibular anterior region was selected. The patient was under invisible orthodontics. Two three-dimensional finite element models were constructed based on the patient’s preoperative and 6-month postoperative cone beam CT data. Both models simulated the movement of tooth 33: experiment I: distal-central movement of 0.25 mm; experiment II: lingual movement of 0.25 mm; and experiment III: intrusion movement of 0.10 mm. The stress distribution and initial displacement trend of tooth 33, periodontal ligament and surrounding alveolar bone under the action of the invisible aligner were analyzed before and after the PAOO procedure. RESULTS AND CONCLUSION: Dental stress analysis: In the same orthodontic tooth movement, the maximum Von-Mises stress and overall stress values of tooth 33 were all higher before surgery than after surgery; there were similar distribution areas of maximum equivalent stress and overall distribution trends of Von-Mises stress before and after surgery. Periodontal ligament stress analysis: In the same orthodontic tooth movement, the maximum Von-Mises stress and overall stress values of the periodontal ligament were higher before surgery than after surgery, and there were similar distribution areas of the maximum equivalent stress and overall distribution trends of Von-Mises stress before and after surgery. Alveolar bone stress analysis: In the same orthodontic tooth movement, the maximum Von-Mises stress values of the alveolar bone around tooth 33 were higher before surgery than after surgery, while the equivalent stress distribution showed a gradual decrease from the top of the alveolar ridge to the root. Initial displacement analysis: In the same orthodontic tooth movement, the initial displacements in the main displacement direction for all six observation points of tooth 33 were smaller before surgery than after surgery, and showed a tendency to gradually decrease from the tooth tip to the apex. Therefore, there were differences in the biomechanical characteristics of orthodontic tooth movement before and after the PAOO surgery. With the clear aligner, the postoperative equivalent stress values on the dentition, periodontal ligament, and surrounding alveolar bone were lower than before the surgery, and the initial displacements of the orthodontic teeth after the surgery are larger than before. These findings suggest that PAOO can release the restriction of thin alveolar bone on the movement of orthodontic tooth by increasing alveolar bone thickness, effectively improving the force on the roots, periodontal ligament, and alveolar bone, avoiding the stress concentration on orthodontic tooth in the thin alveolar bone area that can cause complications when moving, and improving the efficiency of tooth movement. [ABSTRACT FROM AUTHOR]

Gears are significant machine elements used in various industrial applications. An undetected fault in a gear transmission system may lead to a fatal breakdown and, thus, severe economic losses or even human casualties. From this standpoint, the present study developed a numerical method to detect root crack damages in symmetric and asymmetric involute spur gears. To achieve this end, the single tooth stiffness values were calculated for healthy and cracked (25%-50%-75%-100%) gears, and then the time-varying mesh stiffness was obtained. A six-degree-of-freedom dynamic model of a single-stage gear mechanism was developed to collect vibration and Dynamic Transmission Error (DTE) signals. The efficacy of vibration and DTE responses in fault detection was compared through six statistical indicators. The results indicate that the vibration signals were more effective than DTE in detecting tooth root cracks. It was observed that the statistical indicator changes significantly increase with the increment of the drive side pressure angle from 20° to 30° for the backup ratios where the root crack propagates along the tooth, thus making fault detection easier. The findings could provide significant outputs for a better understanding of the influence of tooth asymmetry on gear dynamics characteristics and early fault diagnosis. [ABSTRACT FROM AUTHOR]

Artificial intelligence (AI) has been recently introduced into clinical dentistry, and it has assisted professionals in analyzing medical data with unprecedented speed and an accuracy level comparable to humans. With the help of AI, meaningful information can be extracted from dental databases, especially dental radiographs, to devise machine learning (a subset of AI) models. This study focuses on models that can diagnose and assist with clinical conditions such as oral cancers, early childhood caries, deciduous teeth numbering, periodontal bone loss, cysts, peri-implantitis, osteoporosis, locating minor apical foramen, orthodontic landmark identification, temporomandibular joint disorders, and more. The aim of the authors was to outline by means of a review the state-of-the-art applications of AI technologies in several dental subfields and to discuss the efficacy of machine learning algorithms, especially convolutional neural networks (CNNs), among different types of patients, such as pediatric cases, that were neglected by previous reviews. They performed an electronic search in PubMed, Google Scholar, Scopus, and Medline to locate relevant articles. They concluded that even though clinicians encounter challenges in implementing AI technologies, such as data management, limited processing capabilities, and biased outcomes, they have observed positive results, such as decreased diagnosis costs and time, as well as early cancer detection. Thus, further research and development should be considered to address the existing complications. [ABSTRACT FROM AUTHOR]

As the core component of the wind turbine generation gearbox, the gear-rotor-bearing transmission system typically operates in harsh environments, inevitably leading to the occurrence of composite faults in the system, which exacerbates system vibration. Therefore, it is necessary to study the vibration characteristics of wind turbine helical gear-rotor-bearing transmission systems with composite faults. This paper uses an improved energy method to calculate the theoretical time-varying mesh stiffness of a helical gear with a root crack failure. On the premise of considering the time-varying meshing stiffness of the faulty helical gear, the gear eccentric fault, and the nonlinear support force of the faulty bearing, a multi-degree-of-freedom helical gear-rotor-bearing transmission system with compound faults was established by using the lumped parameter method. The dynamic model of the system was solved based on the Runge–Kutta method, and the vibration response of the system under healthy conditions, single faults with gear eccentricity, single faults with tooth root cracks, and coupled bearing composite faults were simulated and analyzed. The results show that the simulation results based on KISSsoft software 2018 version verify the effectiveness of the improved energy method; the existence of single faults and composite faults will cause the fault characteristics in the time domain and frequency domain responses. In this paper, the influence of a single fault and a complex fault on the time domain and frequency domain of the system is mainly discovered through the fault study of the helical rotor-bearing system, and the influence of the fault degree on the vibration of the gear motion system is discussed. The greater the degree of the fault, the more vibration of the system occurs; accordingly, when the system is under the coupling of tooth root crack and bearing fault, there is a significant difference compared with the healthy system and the single fault system. The system vibration has obvious time domain and frequency domain signal characteristics, including periodic pulse impacts caused by gear faults and time domain impact caused by bearing. The fault characteristic frequencies can also be found in the frequency domain. In this paper, the fault study of a helical gear of wind turbine generation provides a reference for the theoretical analysis of the vibration characteristics of the helical gear-rotor-bearing system under various fault conditions, lays a solid foundation for the simulation and subsequent diagnosis of the composite fault signal of the system, and provides help for the fault diagnosis of wind turbine gearboxes in the future. [ABSTRACT FROM AUTHOR]

Key Clinical Message: Main objective of root canal therapy is to locate all the canals, cleaning and shaping, and obturation to obtain fluid tight seal. Failure to locate all canals can lead to the failure of root canal therapy. Variation of pulp aperture, among teeth with multiple roots, constitutes recurring issue during diagnosing and completing efficient endodontic procedures. Understanding normal anatomy features and associated likely modifications is critical in the effective execution of the dental procedure, since the inability to effectively treat simply one canal may end up into endodontic unsuccessful therapy. The paper covers a procedure whereby the root pattern and canals of the maxillary second molar were modified employing an operative microscope and verified with cone‐beam computed tomography (CBCT). Cone‐beam computed tomography revealed that the maxillary second molar containing two different palatal roots and canals and two distinct buccal roots and canals. This Research paper presents and investigates the morphological difference observed on the maxillary second molar in order to guarantee the effectiveness of root canal treatment examined utilizing imaging techniques like CBCT. [ABSTRACT FROM AUTHOR]

Aim: To investigate the prevalence of apical periodontitis (AP) and the technical standard of root canal treatment in a Belgian population, assess the association of different variables with periapical status, and compare the results to a similar study conducted 22 years previously. Methodology: In this cross‐sectional study, 614 panoramic radiographs of first‐time adult attendees at the Dental School of the University Hospital of Ghent were examined. Recorded patient‐level parameters included gender, age, number of teeth, number of root filled teeth, presence of any AP lesion, and number of implants. The following tooth‐level data were collected: tooth presence, coronal status, quality of coronal restoration, post presence, type of root‐filling material, length and density of root filling, root‐end filling material, presence of AP, and adjacent implant. Multivariable multilevel binary logistic regression was used to explore the association between patient and tooth characteristics and AP prevalence. Risk differences and confidence intervals were calculated to compare the present with the previous study. Results: The prevalence of AP at patient and tooth level was 46.9% and 5.6%, respectively. Fifty‐one per cent of the 614 patients had at least one root filled tooth, and 5.9% of the 14 655 teeth studied were root filled. AP was found in 45% of root filled teeth. Fifty‐four per cent of the root‐filled teeth were rated as inadequate. Multivariable multilevel logistic regression revealed that more teeth, more implants, fewer root‐filled teeth, adequate density, adequate coronal restoration, and no caries reduced the likelihood of AP. There were no statistically significant differences between the two studies regarding the prevalence of root‐filled teeth or AP and the technical quality of root canal treatment. Conclusions: The prevalence of AP and the technical quality of root canal treatment in Belgium have not substantially changed over the last 22 years, despite the technological advancements and continuing education in the field. [ABSTRACT FROM AUTHOR]

Implant prosthesis is the most appropriate treatment for dentition defect or dentition loss, which usually involves a surgical guide design process to decide the implant position. However, such design heavily relies on the subjective experiences of dentists. In this paper, a transformer-based Implant Position Regression Network, ImplantFormer, is proposed to automatically predict the implant position based on the oral CBCT data. We creatively propose to predict the implant position using the 2D axial view of the tooth crown area and fit a centerline of the implant to obtain the actual implant position at the tooth root. Convolutional stem and decoder are designed to coarsely extract image features before the operation of patch embedding and integrate multi-level feature maps for robust prediction, respectively. As both long-range relationship and local features are involved, our approach can better represent global information and achieves better location performance. Extensive experiments on a dental implant dataset through fivefold cross-validation demonstrated that the proposed ImplantFormer achieves superior performance than existing methods. [ABSTRACT FROM AUTHOR]

Objectives: To determine the mandibular anatomical structures by observing cone-beam computed tomography (CBCT) from multiple angles. Materials and methods: This retrospective study analyzed 1593 consecutive CBCT images. Ultimately, 95 CBCTs met the inclusion criteria. The mandibular, inferior lingual, and bony canals at the tooth apex were studied by multi-angle observation CBCT. Descriptive statistics were used for statistical analysis. Results: It is beneficial to further observe the anastomosis of the mandibular, lingual, and mandibular canals when the course of the mandibular lingual canal is observed on CBCT cross-section. The frequency of the inferior lingual canal anastomosis with the mandibular canal was 43.2% (95% confidence interval (CI) 33, 53.3) in the sample. The mental foramen was located below the long axis of the tooth in a few samples, with an occurrence rate of 29.5% (95% CI 20.1, 38.8). The occurrence rate of various types of the bony canal at the apex of the tooth in canines, first premolars, second premolars, first molars, and second molars under the root apex was recorded through the multi-angle observation of the dental volume reformat (DVR) and three-dimensional (3D) levels in CBCT. Conclusion: This study demonstrates the utility of CBCT imaging in examining mandibular anatomy from multiple angles, providing valuable insights into anatomical variations, and enhancing our understanding of mandibular structures. This research emphasizes the crucial role of meticulous CBCT examination in precisely identifying and understanding key anatomical structures, ultimately reducing the risk of surgical complications. Critical relevance statement: By examining cone-beam computed tomography scans from various perspectives, it is possible to determine the precise position of anatomical structures within the jaw. This allows for a more accurate assessment, reducing the risk of harm to these structures during treatment. Key points: • It is crucial to utilize image data effectively to enhance the comprehension of human anatomy. • We captured detailed images of the mandible from different angles and orientations utilizing cone-beam computed tomography (CBCT). • This study provides essential anatomical information for procedural planning to ensure optimal outcomes and patient safety. [ABSTRACT FROM AUTHOR]

Background: Cementoblastoma is a rare odontogenic tumor characterized by the formation of osteocementum-like tissue on a tooth root directly by neoplastic cementoblasts. Although it is categorized as benign, it has a high potential for growth with a certain degree of recurrence risk. However, there are only a few studies describing the features of recurrent cementoblastoma. The diagnosis of recurrent cementoblastoma is challenging not only due to its cytological atypia but also because of its large size and multicentric growth pattern. These characteristics suggest a potential for malignancy. Case presentation: A 29-year-old woman was transferred to our university dental hospital complaining of swelling of the right mandible. She had a history of enucleation of cementoblastoma associated with the third molar of the right mandible. Five years after the initial treatment, imaging demonstrated well-circumscribed multicentric radiopaque lesions in the same area. Histologically, the lesion consisted of osteocementum-like tissue rimmed with polygonal or plump tumor cells. Several cells were large epithelioid cells with bizarre nucleoli, which may be reminiscent of malignant tumors. Otherwise, there were no apparent malignant findings, including proliferative activity or atypical mitotic figure. Besides, tumor cells were positive for c-FOS, a marker of osteoblastoma and cementoblastoma. Eventually, the patient was diagnosed with recurrent cementoblastoma. Conclusions: Pathological analyses of this case suggested that the recurrent event in the cementoblastoma altered its growth pattern and tumor cell shape. Moreover, in the case of enucleation surgery, long-term follow-up is important because there is some recurrent risk of cementoblastoma, although it is not high. [ABSTRACT FROM AUTHOR]

Background: Bioactivity refers to the ability of a material to interact with living organisms or biological systems in a way that elicits a specific response. In the context of materials science and medicine, bioactivity is particularly important because it can determine the suitability of material for various applications. Objective: To evaluate and compare different commercially available calcium silicate-based materials regarding: 1. Morphological and elemental analysis at the dentin/material interface. 2. Calcium and silicon release and uptake by adjacent root canal dentine by evaluating the calcium and silicon incorporation depth in adjacent root canal dentin. Materials and Methods: This study examined four calcium silicate-based cements: Biodentine, MTA Angelus, BioAggregate, and MTA Plus. One hundred extracted human teeth with intact apices and no cavities were selected. Root sections measuring 3 mm in length were created at the mid-root level using low-speed diamond discs. Bioactivity was evaluated at 1, 7, 30, and 90 days, respectively. Results: The principal composition of the interfacial dentine layer and incorporation of calcium and silicon into dentine was measured at 1, 7, 30, and 90 days. Statistical analysis was performed by multiple comparisons using post hoc Tukey HSD. Conclusion: All the materials have shown bioactivity, i.e. release of calcium, silicon, and their uptake in the adjacent dentin in the presence of phosphate-buffered saline. [ABSTRACT FROM AUTHOR]

There are limited reports of mandibular infections and tooth root abscesses in camels (Old World Camelids). This is in contrast to multiple reports and case series detailing diagnosis, management, and therapy of similar infections in New World Camelids such as llamas and alpacas. The purpose of this case series is to present three cases of camels in North America with these infections and to detail the diagnostics, therapeutic interventions, management, and follow-up of these cases. Radiography was utilized in all three cases, as was sedation and/or anesthesia. Similar to llamas, florfenicol was used for antimicrobial therapy and flunixin meglumine was utilized as a nonsteroidal anti-inflammatory. Some degree of lavage was required for the management of each case. Clinicians should be aware of the potential need for sedation, diagnostic imaging, culture, and extended therapies for the treatment of mandibular and tooth root infections in camels as comparatively described for llamas and alpacas. [ABSTRACT FROM AUTHOR]

This study evaluated the stress distribution on an implant-supported zirconia crown of a mandibular first molar subjected to oblique loading by occlusal contact with the natural maxillary first molar by using the 3D finite element method. Two virtual models were made to simulate the following situations: (1) occlusion between maxillary and mandibular natural first molars; (2) occlusion between zirconia implant-supported ceramic crown on a mandibular first molar and maxillary natural first molar. The models were designed virtually in a modeling program or CAD (Computer Aided Design) (Rhinoceros). An oblique load of 100 N was uniformly applied to the zirconia framework of the crown. The results were obtained by the Von Mises criterion of stress distribution. Replacement of the mandibular tooth by an implant caused a slight increase in stress on portions of the maxillary tooth roots. The crown of the maxillary model in occlusion with natural antagonist tooth showed 12% less stress when compared with the maxillary (model in occlusion with the) implant-supported crown. The mandibular crown of the implant show 35% more stress when compared with the mandibular antagonist crown on the natural tooth. The presence of the implant to replace the mandibular tooth increased the stresses on the maxillary tooth, especially in the region of the mesial and distal buccal roots. [ABSTRACT FROM AUTHOR]

Aim: To investigate the association of various pre‐, intra‐ and post‐operative factors on root canal treatment outcome. Methodology: In this cohort study, primary or secondary root canal treatment of mature permanent teeth was performed by a single endodontist in a private practice over 13 years, and followed 1–4 years after treatment. Treatment details and clinical and radiographic data were collected. The proportion of successfully treated teeth and roots based on strict radiographic (periapical index (PAI) ≤2) and clinical criteria (absence of pain, swelling or sinus tract) was estimated. To evaluate joint associations of prognostic factors and treatment success probability, 44 pre, intra‐ and post‐operative factors were investigated using bivariate associations, and a multiple logistic regression model was fitted using Generalized Estimating Equations. Results: 1259 teeth (2445 roots, 3149 canals) were assessed with a recall rate of 91%. The proportion of successfully treated teeth was 79.9% [95% confidence interval 77.7–82.1]. Eleven prognostic factors were identified that significantly reduced the odds ratio (OR) for treatment success at tooth level. Six were preoperative: injury history (OR = 0.05[0.01–0.24]), root PAI (OR = 0.29[0.20–0.42], 0.21[0.13–0.34] and 0.22[0.12–0.42] for PAI = 3, 4 and 5, respectively, against PAI = 1), lesion diameter (OR = 0.30[0.21–0.43] and 0.24[0.16–0.37] for diameters of 1‐5 mm and ≥6 mm, respectively, against no lesion), tooth type (OR = 0.51[0.27–0.97] and OR = 0.45[0.24–0.83] for premolars and molars, respectively, against incisors or canines), tenderness to periapical palpation (OR = 0.64[0.43–0.94]) and two canals per root (OR = 0.67[0.54–0.83]). Four factors were intraoperative: root filling of unsatisfactory quality (OR = 0.18[0.08–0.40]) or extending beyond or shorter than 2 mm from the apex (OR = 0.44[0.26–0.75] and 0.62[0.40–0.97] respectively), resin sealer (OR = 0.58[0.39–0.87] against bioceramic sealer) and single visit treatment (OR = 0.40[0.21–0.75] against multiple visits). One factor was post‐operative: defective coronal restoration (OR = 0.35[0.21–0.56]). Conclusion: The following factors were associated with unsuccessful root canal treatment: (i) history of injury, apical periodontitis with increased severity (larger lesion, higher PAI, tenderness to periapical palpation), or complicated anatomic conditions (premolar or molar, two canals in a single root); (ii) technically suboptimal root filling (of unsatisfactory quality or not ending within 2 mm of radiographic apex) performed in a single‐visit, or use of resin sealer instead of novel bioceramic sealer; (iii) suboptimal quality coronal restoration. [ABSTRACT FROM AUTHOR]

Aim: To assess and compare the short‐term clinical outcomes following a combined vertical and horizontal alveolar ridge augmentation and two‐stage implant placement using either autogenous tooth roots (TR) or autogenous bone blocks (AB). Materials and methods: A total of n = 27 patients (TR/AB: 13/14) exhibiting n = 31 implants (TR/AB: 14/17) were available for the analysis. Each subject had been allocated to a combined vertical and horizontal alveolar ridge augmentation using either (1) healthy TR (e.g., retained wisdom teeth), or (2) monocortical AB harvested from the retromolar area (i.e. external oblique line). Clinical parameters (e.g., bleeding on probing, BOP; probing pocket depth, PD; mucosal recession, MR) were recorded after a follow‐up period of 16.03 ± 4.3 months following implant placement. Results: The survival rates amounted to 100% in both groups. TR and AB grafted sites were associated with similar changes in mean BOP (8.97 ± 27.73%; 11.90 ± 18.97%), PD (0.53 ± 0.49; 0.47 ± 0.67 mm), and MR (0.03 ± 0.13; 0.0 ± 0.02 mm) values. The incidence of peri‐implant mucositis and peri‐implantitis at the patient level amounted to 15.38% and 0.0% in the TR‐, and 28.57% and 7.14% in the AB group. Conclusions: Both surgical procedures were associated with peri‐implant tissue health and stability on the short‐term. [ABSTRACT FROM AUTHOR]

Objectives: To identify the molecular etiology of distinct dental anomalies found in eight Thai patients and explore the mutational effects on cellular functions. Materials and Methods: Clinical and radiographic examinations were performed for eight patients. Whole exome sequencing, mutant protein modelling, qPCR, western blot analysis, scratch assays, immunofluorescence, confocal analysis, in situ hybridization, and scanning electron micrography of teeth were done. Results: All patients had molars with multiple supernumerary cusps, single‐cusped premolars, and a reduction in root number. Mutation analysis highlighted a heterozygous c.865A>G; p.Ile289Val mutation in CACNA1S in the patients. CACNA1S is a component of the slowly inactivating L‐type voltage‐dependent calcium channel. Mutant protein modeling suggested that the mutation might allow leakage of Ca2+ or other cations, or a tightening, to restrict calcium flow. Immunohistochemistry analysis showed expression of Cacna1s in the developing murine tooth epithelium during stages of crown and root morphogenesis. In cell culture, the mutation resulted in abnormal cell migration of transfected CHO cells compared to wildtype CACNA1S, with changes to the cytoskeleton and markers of focal adhesion. Conclusions: The malformations observed in our patients suggest a role for calcium signaling in organization of both cusps and roots, affecting cell dynamics within the dental epithelium. [ABSTRACT FROM AUTHOR]

A time-varying meshing stiffness (TVMS) model that includes oil film stiffness in the elastohydrodynamic lubrication (EHL) line contact is proposed for tooth root cracking. This model employs the oil film thickness to estimate the stiffness of the oil film in gear contact by considering the profile variation of the oil film induced by tooth root cracks, to provide the evolution principle of TVMS in EHL line contact to study the effects of oil film stiffness of cracked gear on the TVMS. The results of the analysis reveal that the overall result of TVMS decreases owing to the stiffness of the oil film, whereas the combined TVMS depends mainly on the rotation speed of the gear system because the thickness of the oil film in the tooth crack is affected by the velocity of the entrainment. Furthermore, a six-degree-of-freedom (DOF) dynamic model is introduced to analyze the vibration behavior of the gear system using the combined TVMS results for different crack levels, and the influence of the combined TVMS on the vibration response of the tooth root crack is exhibited from the time-domain analysis, frequency-domain analysis, and statistical indicator analysis. [ABSTRACT FROM AUTHOR]

A recent study reported that micro-osteoperforations (MOPs) accelerated tooth movement by activating alveolar bone remodeling. However, very little is known about the relationship between MOPs and external apical root resorption during orthodontic treatment. In this study, in order to investigate the mechanism through which MOPs accelerate tooth movement without exacerbating the progression of root resorption, we measured the volume of the resorbed root, and performed the terminal deoxynucleotidyl transferase (TdT)-mediated dUTP-biotin nick-end labeling (TUNEL) method on exposed MOPs during experimental tooth movements in rats. Male Wistar rats (11 weeks old) were divided into three groups: 10 g orthodontic force (optimal force) applied to the maxillary first molar (optimal force: OF group), 50 g orthodontic force application (heavy force: HF group), and 10 g force application plus three small perforations of the cortical plate (OF + MOPs group). On days 1, 4, 7, 10, and 14 after force application, the tooth movement and root volume were investigated by micro-computed tomography. Furthermore, the number of apoptotic cells in the pressured sides of the periodontal ligament (PDL) and surrounding hard tissues were determined by TUNEL staining. The OF + MOPs group exhibited a 1.8-fold increase in tooth movement on days 7, 10, and 14 compared with the OF group. On days 14, the HF group had a higher volume of root loss than the OF and OF + MOPs groups. On the same day, the number of TUNEL-positive cells in the HF group increased at the root (cementum) site whereas that in the OF group increased at the alveolar bone site. Furthermore, the number of TUNEL-positive cells in the OF + MOPs group increased at the alveolar bone site compared with the OF group. These results suggest that MOPs accelerate orthodontic tooth movement without exacerbating the progression of root resorption. [ABSTRACT FROM AUTHOR]

Failure to locate a complete canal system affects the prognosis of root canal treatment. A missed root canal is one of the most common reasons for failed root canal treatment. The prevalence of the second mesiobuccal canal in the maxillary second molar is relatively high and has a variety of configurations. Therefore, knowledge of its morphology is required in clinical endodontics. This review presented the canal in terms of its prevalence, classification, anatomical features, and the method for locating the second mesiobuccal canal in the maxillary second molar. Root canal treatment requires knowledge of tooth morphology, appropriate access preparation, and a thorough examination of the tooth's interior. Thus, clinicians should carefully employ various methods for assessing the anatomy of the entire root canal system to prevent failure in locating the second mesiobuccal canal. This canal can be located by modifying the access cavity design and utilizing specific instruments to improve the second mesiobuccal canal system visualization. [ABSTRACT FROM AUTHOR]

Background: Edentulous sites with limited horizontal tooth‐implant distance pose a challenge to clinicians. This case report describes root amputation of an adjacent compromised molar to maintain an optimal tooth‐implant distance Methods and Results: A 41‐year‐old female was referred for extraction and implant placement to replace her left, maxillary second premolar (#13), which had been diagnosed with a vertical root fracture. Extraction and ridge preservation of #13 was completed without complication. The 4‐month postsurgical clinical examination revealed a narrow mesial‐distal distance (5.69 mm) of the edentulous space (#13), which was influenced by the degree of divergence of the mesial buccal root of tooth #14. Cone‐beam computed tomography (CBCT) analysis verified a periapical lesion on the mesial‐buccal root of tooth #14. The amputation of the endodontically compromised mesial‐buccal root of #14 was treatment planned to provide space and facilitate placement of a standard diameter implant without compromising the implant or adjacent teeth. Crestal bone levels were verified and maintained at the 1 year postoperative follow‐up. Conclusion: The findings of the case report demonstrate how root amputation of a compromised molar is an alternative solution for managing spatial limitations in contemporary implant dentistry. More studies are required to assess the reliability and long‐term success of this approach. Key points: Why is this case new information?There is insufficient evidence on the long‐term efficacy of narrow‐diameter implants. Clinical treatment guidelines are not sufficiently available.This paper presents an alternative approach to managing a specific scenario where mesial‐distance distance is limited using root amputation of an adjacent compromised tooth. What are the keys to successful management of this case?Comprehensive diagnosis and stringent case selectionMultidisciplinary treatment planningEvidence‐based decision making What are the primary limitations to success in this case?Very specific clinical application; adjacent compromised toothLong‐term follow up is required [ABSTRACT FROM AUTHOR]

Objectives: Intrapulpal calcifications can occur in the dental pulp of patients with diabetes. We focused on the association between ectopic calcifications in the dental pulp and advanced glycation end products (AGEs) in Spontaneously Diabetic Torii (SDT)‐fatty rats, an obese type 2 diabetic rat model, to determine the mechanism of calcification with pulp stone in the dental pulp. Materials and Methods: Pathologic calcification in the dental pulp of SDT‐fatty rats was observed using electron microscopy and immunohistochemical analysis. Moreover, mechanical analysis of periapical region of molar tooth against occlusal force was performed. Results: In SDT‐fatty rats, pathogenic pulpal calcifications occurred during blood glucose elevation after 6 weeks, and granular calcification was observed in the dental pulp after 11 weeks. Pentosidine, a major AGE, and the receptor for AGEs were strongly expressed in the dental pulp of SDT‐fatty rats. S100A8, TNF‐α, and IL‐6 also showed positive response in the dental pulp of the SDT‐fatty rat, which indicated pulpal inflammation. Blood flow disorder and hypoxic dental pulp cells were also observed. In silico simulation, strain from occlusal force concentrates on the root apex. Conclusions: Glycation makes blood vessels fragile, and occlusal forces damage the vessels mechanically. These are factors for intrapulpal calcification of diabetes. [ABSTRACT FROM AUTHOR]

Tooth flank fracture (TFF) and tooth interior fatigue fracture (TIFF) usually occur on case-harden gears in electromechanical coupling systems, both starting from the core caused by metal fatigue. The cracks propagate rapidly compared with the total life of a gear, so that it is necessary to detect and identify the faults in time when they take place in order to avoid danger. In this paper, the time-varying mesh stiffness model of two types of faults is established by the potential energy method and validating by the finite element method. Based on the stiffness model, the influence of faults on the electromechanical system and their fault characteristics are analyzed, which provides a theoretical basis for the health detection of electromechanical coupling systems. The results indicate that in the early stage of the three faults, i.e., tooth root fracture, tooth interior fatigue fracture, and tooth flank fracture, it is hard to discriminate the faults. But after the second stage, the faults can be distinguished by the vibration amplitude, frequency band components, and phase diagrams. The TFF can be discerned into different stages by frequency domains and phase diagrams. When the fracture occurs completely, three faults can be easily distinguished by the time domain and phase diagram. In the frequency domain, the TRF can also be distinguished from the other two faults by referring to the sideband component near the meshing frequency. [ABSTRACT FROM AUTHOR]

Large isolated skeletal elements, including those of sphenacodontid and ophiacodontid synapsids from the upland cave systems of the Richards Spur locality, Oklahoma, are described. Multiple forms of visual representation, including coquille and stipple drawings, are used to document and examine the isolated elements. A fragmentary anterior portion of a dentary has the sphenacodontid four-leaf clover plicidentine attachment within the tooth roots, but the teeth are all of uniform size, and the symphyseal area is relatively slender and does not curve upward, suggesting that the specimen may not belong to any known member of the clade. A larger humerus with only the distal end preserved and a complete astragalus have distinct characteristics which are attributable to the sphenacodontid Dimetrodon Cope, 1878. A second, smaller humerus was identified to belong to Ophiacodon Marsh, 1878, cf. O. navajovicus and represents the first record of an ophiacodontid at Richards Spur. Finally, two large sphenacodontid interclavicles were discovered, with one having unusual growths representing a pathological condition. Typically, large amniotes are quite rare in this early Permian upland ecosystem, but the discovery of the new material shows that large synapsids are present at Richards Spur. [ABSTRACT FROM AUTHOR]

Objective: To evaluate root coverage (RC) in deep single antero‐mandibular RT2 and RT3 gingival recessions (GR) and to investigate the influence of several factors in RC. Materials and Methods: Fifteen single antero‐mandibular GR with a minimum depth of 3 mm were consecutively treated with a new one‐stage technique (laterally positioned flap with a tunnel access and a connective tissue graft). At baseline and at 12‐month follow‐up, the percentage of mean root coverage (%MRC), the recession reduction (RecRed), complete root coverage (CRC) and the gain of keratinized tissue width (KTW) were assessed. Descriptive, intergroup comparative and correlation analyses were performed. Results: At 12 months, a %MRC of 77.29 ± 21.48% with a mean RecRed of 4.10 ± 1.51 mm was achieved. The %MRC was 84.71 ± 21.08% in RT2, and 62.43 ± 14.17% in RT3. The mean gain of KTW was 2.10 ± 0.89 mm, with a mean gain of 2.0 ± 1.03 mm for RT2 and 2.3 ± 0.57 mm for RT3. CRC was observed in six cases, all of them being RT2. A positive association was found between the %MRC and the initial position of the tooth and of both papillae. Conclusions: This technique might be a valuable approach for the treatment of deep single antero‐mandibular RT2 and RT3 recessions, even in malpositioned teeth. Clinical Significance: A combination of different surgical techniques could provide greater vascularization to the CTG especially in malpositioned teeth in sextant V with a large avascular area to be covered. [ABSTRACT FROM AUTHOR]

Background: The aim of this systematic review was two‐fold: (i) to evaluate the long‐term (≥5 years) stability of the gingival margin position, keratinized tissue width (KTW) and gingival thickness (GT) in sites that underwent root coverage (RC) or gingival augmentation (GA); and (ii) to assess the influence of different local variables on the long‐term stability of dental and gingival tissues. Materials and Methods: Randomized controlled trials (RCTs) and non‐RCTs reporting short‐term (i.e., 6–12 months after baseline surgical intervention) and long‐term (≥5 years) follow‐up data after surgical treatment of adult patients presenting single or multiple mucogingival deformities, defined as sites presenting gingival recession defects (GRDs) and/or (KTW) deficiency (i.e., <2 mm), were considered eligible for inclusion. MEDLINE–PubMed, EMBASE and Cochrane Central Register of Controlled Trials databases were searched for articles published up to 15 May 2023. Mixed‐effects multiple linear regression was used to assess the association between KTW, type of surgical procedure and time (i.e., independent variables) on the stability of the gingival margin in sites that received RC or GA therapy. Results: Of the 2569 potentially eligible records, 41 (reporting 40 studies) met the eligibility criteria. Graphical estimates including data from all RC procedures found an upward trend in recession depth (RD) increase over time. Conversely, it was observed that in 63.63% of RC studies and in 59.32% of RC treatment arms KTW increased over time, particularly in sites treated with subepithelial connective tissue grafts (SCTGs). Conversely, sites that underwent GA procedures generally exhibited an overall reduction of KTW over time. However, sites treated with free gingival grafts (FGGs) showed a decrease in RD after 10 years of follow‐up. Three main findings derived from the pooled estimates were identified: (i) Gingival margin stability was associated with the amount of KTW present during short‐term assessment (i.e. the greater the KTW at 6–12 months after treatment, the more stable the gingival margin). (ii) The use of autogenous soft‐tissue grafts was associated with lower RD increase over time. (iii) Treatment approaches that contribute to the three‐dimensional enhancement of the gingival phenotype, as clearly demonstrated by FGG, were associated with gingival margin stability. Conclusions: The extent of apical migration of the gingival margin appears to be directly related to the amount of KTW and GT upon tissue maturation. Interventions involving the use of autogenous grafts, either SCTG or FGG, are associated with greater short‐term KTW gain and lower RD increase over time. [ABSTRACT FROM AUTHOR]

The article discusses the prevalence and evaluation of postoperative pain following root canal treatment. It highlights the increase in clinical trials focusing on postoperative pain as a primary outcome, but questions the relevance of short-term pain studies in determining the efficacy of different irrigation protocols. The article emphasizes the subjective nature of pain and the presence of confounding factors that make it challenging to attribute pain solely to irrigation. It suggests that longer-term follow-up or the control of various variables is necessary for more meaningful results. The article concludes by suggesting the consideration of objective surrogate outcomes, such as inflammatory markers, in future studies. [Extracted from the article]

A novel methodology for determining the singular point of an enveloped surface is put forward. Unlike some existing methods, the presented method starts directly from the equation of the enveloped surface instead of that of the generating surface, and it is thus called a direct method. The calculation for the normal vector of the enveloped surface is well simplified with the help of the moving frame approach, which makes the presented method feasible. The singularity condition equation is extracted by using the theory of linear algebra. For singular points with different properties, proper solving techniques are established, including resultant elimination and simple elimination. Applying the developed method, the undercutting characteristics of the Archimedes worm wheel are investigated from the perspective of spatial meshing. The numerical results demonstrate that the worm wheel generally has one undercutting limit line, whose trend is along the tooth width of the wheel. Locating on one side of the tooth surface and near the tooth root is a dangerous part of the worm wheel undercutting. The proposed method is beneficial for the development of gear meshing science. [ABSTRACT FROM AUTHOR]

BACKGROUND: Root canal preparation is a key step in root canal therapy. In recent years, with the rapid development of new nickel-titanium instruments, the results of root canal shaping ability have been significantly improved. However, the shaping abilities of different nickel-titanium instruments are also different. At present, there are few reports about the influence of the shaping ability of R-phase heat treatment NIC X-FILE and DENCO Pre-Shaper in simulated curved canals. OBJECTIVE: To compare the shaping effect of NIC X-FILE and DENCO Pre-Shaper nickel-titanium instruments in preparation for simulated curved canals. METHODS: Fifty simulated resin-curved canals were selected and randomly divided into two groups (n=25). NIC X-FILE and DENCO Pre-Shaper nickel-titanium files were used for root canal preparation. The root canal preparation time was recorded. Images of pre-and post-root canal preparation were taken. Image processing and analysis software were used to measure the amount of resin removed from the inner and outer walls of the root canal at each observation point. Statistical software was used to compare the root canal preparation time and centering ability of two kinds of mechanical nickel-titanium files. RESULTS AND CONCLUSION: (1) The average root canal preparation time was (1.58±0.02) minutes in the DENCO Pre-Shaper group and (2.22±0.03) minutes in the NIC X-FILE group. There was a significant difference between the two groups (P < 0.05). (2) The amount of resin removed from the inner walls of the root canal of the DENCO Pre-Shaper group at 4, 5, 7, 8, 9, and 10 mm from the apical foramen was higher than that of the NIC X-FILE group (P < 0.05). The amount of resin removed from the outer walls of the root canal of the DENCO Pre-Shaper group at 3, 5, 6, 7, and 8 mm from the apical foramen was lower than that of the NIC X-FILE group (P < 0.05). (3) At 2, 4, 5, 6, 7, 8, and 9 mm away from apical foramen, the centering ability of the NIC X-FILE group was better than that of the DENCO Pre-Shaper group (P < 0.05), and the centering ability of the NIC X-FILE group was the best at 4 mm away from apical foramen. (4) The results show that DENCO Pre-Shaper has higher mechanical efficiency than NIC X-FILE nickel-titanium root canal files. However, the centering ability of DENCO Pre-Shaper is inferior to NIC X-FILE nickel-titanium root canal files. [ABSTRACT FROM AUTHOR]

Nerves play important roles in organ development and tissue homeostasis. Stem/progenitor cells differentiate into different cell lineages responsible for building the craniofacial organs. The mechanism by which nerves regulate stem/progenitor cell behavior in organ morphogenesis has not yet been comprehensively explored. Here, we use tooth root development in mouse as a model to investigate how sensory nerves regulate organogenesis. We show that sensory nerve fibers are enriched in the dental papilla at the initiation of tooth root development. Through single cell RNAsequencing analysis of the trigeminal ganglion and developing molar, we reveal several signaling pathways that connect the sensory nerve with the developing molar, of which FGF signaling appears to be one of the important regulators. Fgfr2 is expressed in the progenitor cells during tooth root development. Loss of FGF signaling leads to shortened roots with compromised proliferation and differentiation of progenitor cells. Furthermore, Hh signaling is impaired in Gli1-CreER;Fgfr2fl/fl mice. Modulation of Hh signaling rescues the tooth root defects in these mice. Collectively, our findings elucidate the nerve-progenitor crosstalk and reveal the molecular mechanism of the FGF-SHH signaling cascade during tooth root morphogenesis. [ABSTRACT FROM AUTHOR]

Following the development of modern genome sequencing technologies, the investigation of museum osteological finds is increasingly informative and popular. Viable protocols to help preserve these collections from exceedingly invasive analyses, would allow greater access to the specimens for scientific research. The main aim of this work is to survey skeletal tissues, specifically petrous bones and roots of teeth, using infrared spectroscopy as a prescreening method to assess the bone quality for molecular analyses. This approach could overcome the major problem of identifying useful genetic material in archaeological bone collections without resorting to demanding, time consuming and expensive laboratory studies. A minimally invasive sampling of archaeological bones was developed and bone structural and compositional changes were examined, linking isotopic and genetic data to infrared spectra. The predictive model based on Infrared parameters is effective in determining the occurrence of ancient DNA (aDNA); however, the quality/quantity of aDNA cannot be determined because of the influence of environmental and local factors experienced by the examined bones during the burial period. [ABSTRACT FROM AUTHOR]

Jaw cysts commonly affect the oral and maxillofacial region, involving adjacent tooth roots. The management of these teeth, particularly regarding root canal therapy and apicoectomy, lacks consensus. This study introduces a novel treatment concept and refined surgical approach to preserve pulp viability in teeth involved in jaw cysts. The objective was to investigate the effectiveness and potential benefits of this approach over a 36-month follow-up period. A conservative management approach prioritized vitality preservation, reserving root canal treatment and apicectomy for cases with post-operative discomfort. A comprehensive follow-up of 108 involved teeth from 36 jaw cyst cases treated with the modified method was conducted. Clinical observation, X-ray imaging, cone-beam computed tomography (CBCT), and pulp vitality testing assessed changes in cyst size, tooth color, pulp vitality, root structure, and surrounding alveolar bone. After 36 months, our modified surgical approach successfully preserved tooth vitality in 84 involved teeth. Adverse symptoms in 19 teeth, such as redness, swelling, fistula, and pain, resolved with postoperative root canal therapy. Follow-up was lost for five teeth in two cases. No cyst recurrences were observed, and in 34 cases, the bone cavity gradually disappeared, restoring normal bone density during long-term follow-up. Our modified surgical method effectively preserves tooth vitality in jaw cysts. This innovative approach has the potential to improve the management of teeth involved in jaw cysts. [ABSTRACT FROM AUTHOR]

In traumatic dental injuries in children, due to a lack of maturity to cope with the situation, pain intolerance, amount of treatment procedure, and parental anxiety, simplified and non-invasive treatment procedures, such as biologic restorations, are useful. Using advanced adhesive material for fragment reattachment provides excellent esthetic results and a positive attitude from the patient and family. The purpose of this case report is to describe the biological restoration of a complicated crown-root fracture of a primary maxillary central incisor with the fragment reattachment technique. [ABSTRACT FROM AUTHOR]

The goals of this review are to improve understanding of the aetiology of chronic muscle pain and identify new targets for treatments. Muscle pain is usually associated with trigger points in syndromes such as fibromyalgia and myofascial syndrome, and with small spots associated with spontaneous electrical activity that seems to emanate from fibers inside muscle spindles in EMG studies. These observations, added to the reports that large‐diameter primary afferents, such as those innervating muscle spindles, become hyperexcitable and develop spontaneous ectopic firing in conditions leading to neuropathic pain, suggest that changes in excitability of these afferents might make an important contribution to the development of pathological pain. Here, we review evidence that the muscle spindle afferents (MSAs) of the jaw‐closing muscles become hyperexcitable in a model of chronic orofacial myalgia. In these afferents, as in other large‐diameter primary afferents in dorsal root ganglia, firing emerges from fast membrane potential oscillations that are supported by a persistent sodium current (INaP) mediated by Na+ channels containing the α‐subunit NaV1.6. The current flowing through NaV1.6 channels increases when the extracellular Ca2+ concentration decreases, and studies have shown that INaP‐driven firing is increased by S100β, an astrocytic protein that chelates Ca2+ when released in the extracellular space. We review evidence of how astrocytes, which are known to be activated in pain conditions, might, through their regulation of extracellular Ca2+, contribute to the generation of ectopic firing in MSAs. To explain how ectopic firing in MSAs might cause pain, we review evidence supporting the hypothesis that cross‐talk between proprioceptive and nociceptive pathways might occur in the periphery, within the spindle capsule. What is the topic of this review?Firing in muscle spindle afferents (MSAs) is generated when their muscle is stretched, but sometimes generated elsewhere along the neuron (ectopic firing) in pathological pain. Appearance of ectopic firing coincides with appearance of pain. We examine mechanisms underlying emergence of ectopic firing in MSAs of the jaw‐closing muscles.What advances does it highlight?Firing in MSAs emerges from oscillations supported by a persistent sodium current, which varies with extracellular Ca2+, which is, in turn, regulated by astrocytes. We emphasize the potential role of astrocytes in appearance of ectopic firing. We proposed an explanation for how activity in MSAs crosses to nociceptors in the periphery. [ABSTRACT FROM AUTHOR]

Aim: Several factors influence the condition of the periapical tissues associated with root filled teeth. The primary objective of this study was to retrospectively evaluate the extent and speed of bone healing of large periapical lesions associated with nonsurgical root canal treatment or retreatment. The secondary objective was to analyse the relationship between the time to complete healing when analysed using cone beam computed tomography (CBCT) and other possible predictors that affect healing. Methodology: Seventy‐nine patients were treated during the years 2013–2020 with large periapical lesions of endodontic origin (10–15 mm) as observed on intraoral periapical radiographs (IOPAR) were included. IOPAR and CBCT were available before treatment and during the follow‐up (IOPAR every 6 months and CBCT every 12 months). The volume of periapical lesions was calculated by OsiriX Lite software. Variables such as initial volume of the lesion, age, gender, type of treatment or type of root canal filling were compared to identify the differences between healed and unhealed lesions. Pearson's Chi‐square test was used for categorical variables, the t‐test for age and the Wilcoxon test for initial volume of the lesion. The association between time to healing and the variables was assessed using univariate analysis and multivariate analysis. The Wilcoxon test was used to observe the association of healing time with categorical variables and the correlation index was measured with the quantitative variables. Results: Of the 79 cases analysed, 60 lesions (76%) were completely healed as verified by CBCT in a mean healing time of 19 months, of which 60% healed fully between 12 and 18 months. Increase in age of patient and larger initial volume of the lesion were associated with a significantly longer healing time (p <.001). Gender, filling material and type of treatment did not have a significant effect on the healing process (p >.05). Conclusions: Clinicians should be aware that periapical lesions in older patients and larger areas of bone loss take longer to heal. CBCT monitoring of large periapical lesions is critical and it can help clinicians in the decision‐making process. [ABSTRACT FROM AUTHOR]

Aim: To explore associations between root filled teeth, primary and secondary apical periodontitis, and levels of inflammatory markers in blood from patients with a first myocardial infarction and matched controls. Methodology: Between May 2010 and February 2014, 805 patients with a first myocardial infarction and 805 controls, matched for sex, age, and postal code area, were recruited to the multicentre case–control study PAROKRANK (periodontitis and its relation to coronary artery disease). All participants underwent a physical and oral examination, as well as blood sampling. Using panoramic radiography, root filled teeth, primary apical periodontitis, and secondary apical periodontitis were assessed by three independent observers. Blood samples were analysed with enzyme‐linked immunosorbent assay method for the following inflammatory markers: interleukin‐1β (IL‐1β), IL‐2, IL‐6, IL‐8, IL‐12p70, tumour necrosis factor‐α, and high‐sensitivity C‐reactive protein (hsCRP). Additionally, white blood cell count and plasma‐fibrinogen were analysed. Associations between endodontic variables and the levels of inflammatory markers were statistically analysed with Mann–Whitney U‐test and Spearman correlation, adjusted for confounding effects of baseline factors (sex, age, myocardial infarction, current smoking, diabetes, family history of cardiovascular disease, education, marital status, and periodontal disease). Results: Mean age of the cohort was 62 years, and 81% were males. Root fillings were present in 8.4% of the 39 978 examined teeth and were associated with higher levels of hsCRP, fibrinogen, and leukocyte count, but lower levels of IL‐2 and IL‐12p70. After adjusting for confounders, root filled teeth remained associated with higher levels of fibrinogen, but lower levels of IL‐1β, IL‐2, IL‐6, and IL‐12p70. Primary apical periodontitis was found in 1.2% of non‐root filled teeth and associated with higher levels of IL‐8 (correlation 0.06, p =.025). Secondary apical periodontitis was found in 29.6% of root filled teeth but did not relate to the levels of any of the inflammatory markers. Conclusions: This study supports the notion that inflammation at the periapex is more than a local process and that systemic influences cannot be disregarded. Whether the observed alterations in plasma levels of inflammatory markers have any dismal effects on systemic health is presently unknown but, considering the present results, in demand of further investigation. [ABSTRACT FROM AUTHOR]

Aim: To evaluate outcomes and predictive factors for the long‐term stability of root coverage using a sub‐epithelial connective tissue graft. Materials and Methods: One‐hundred and two healthy subjects (221 gingival recessions, GRs) were treated from 1987 to 1996. Keratinized tissue width (KTW), GR depth (RD), GR width (RW) and GR area (RA) were evaluated at baseline (M0) and at 1 month (M1), 1 year (M2), 11 years (M3), 21 years (M4) and 27 years (M5) after surgery. Primary outcomes consisted of complete root coverage (cRC) and relative dimensional changes in recession depth (measured in mm [c%‐RD]), recession width (measured in mm [c%‐RW]) and recession area (measured in mm2 [c%‐RA]). Results: cRC was 88.7% at 1 year (M2), 59.8% at M3, 44.4% at M4 and 51.9% at M5. Average c%‐RD was 95.2% at 1 year, 81.9% at M3, 71.5% at M4 and 81.7% at M5. KTW increased after surgery and over time and was positively correlated with favourable outcomes. Increased baseline RA was associated with less favourable clinical outcomes. Conclusions: The sub‐epithelial connective tissue graft is effective in the treatment of GRs and facilitates long‐term stability of clinical outcomes. Wider baseline RA was a strong predictor of unfavourable short‐ and long‐term RC outcomes. [ABSTRACT FROM AUTHOR]

Simple Summary: The survival rate for pediatric cancer has increased over the past few decades, short- and long-term complications have been detected and studied, and oral complications have emerged as an important topic of research. Here, we aimed to highlight the importance of oral manifestations that may only become apparent years or even decades after cancer treatment. Childhood cancer survivors presented a higher risk of having dental alterations than control counterparts. Additional analyses reveal possible sex-based differences that should be explored in future studies. These results collectively highlight the importance of oral healthcare and the prevention of disease in childhood cancer survivors. The survival rate for pediatric cancer has increased over the past few decades, short- and long-term complications have been detected and studied, and oral complications have emerged as an important topic of research. Here, we aimed to highlight the importance of oral manifestations that may only become apparent years or even decades after cancer treatment. This systematic review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis. We searched articles using PubMed via the MEDLINE, Web of Science, and LILACS databases until October 2023. Overall, 35 observational studies were included, and the results estimated a pooled prevalence of the following dental anomalies: discoloration, 53%; crown-root malformations and agenesis, 36%; enamel hypoplasia, 32%; root development alterations, 29%; unerupted teeth, 24%; microdontia, 16%; hypodontia, 13%; and macrodontia, 7%. Most childhood cancer survivors have at least one dental sequela. Childhood cancer survivors presented a higher risk of having dental alterations than control counterparts. Additional analyses reveal possible sex-based differences that should be explored in future studies. These results collectively highlight the importance of oral healthcare and the prevention of disease in childhood cancer survivors. [ABSTRACT FROM AUTHOR]

This study seeks to assess the accuracy of apical location using an augmented reality (AR) device with a free-hand method. Sixty (60) osteotomy site preparations were randomly assigned to one of two study groups: A. AR device (AR) (n = 30), and B. conventional free-hand method (FHM) (n = 30). Preoperative CBCT scans and intraoral scans were taken and uploaded to specialized implant-planning software to virtually plan preparations for the apical location osteotomy sites. The planning software was then used to automatically segment the teeth in each experimental model for their complete visualization using the AR device. A CBCT scan was carried out postoperatively after conducting the apical location procedures. The subsequent datasets were imported into therapeutic software to analyze the coronal, apical, and angular deviations. The Mann–Whitney non-parametric test was used. There were no statistically significant differences identified at the coronal (p = 0.1335), apical (p = 0.2401), and angular deviations (p = 0.4849) between the AR and FHM study groups. The augmented reality technique did not show a statistically significant accuracy of osteotomies for apical location when compared with the conventional free-hand method. [ABSTRACT FROM AUTHOR]

Background: Neurosensory deficits are one of the major complications after impacted lower third molar extraction leading to an impaired patient's quality of life. This study aimed to evaluate the incidence of neurosensory deficits after lower third molar extraction and compare it radiologically to the corresponding position of the inferior alveolar nerve. Methods: In a retrospective study, all patients who underwent impacted lower third molar extraction between January and December 2019 were compiled. Therefore, clinical data as well as preoperative radiological imaging were assessed. Results: In total, 418 patients who underwent lower third molar extractions (n = 555) were included in this study. Of these, 33 (5.9%) had short-term (i.e., within the initial 7 postoperative days) and 12 (1.3%) long-term (i.e., persisting after 12 months) neurosensory deficits documented. The inferior alveolar nerve position in relation to the tooth roots showed apical position in 27%, buccal position in 30.8%, lingual position in 35.4%, and interradicular position in 6.9%. Conclusions: A statistically significant increased incidence of neurosensory deficits occurs when the inferior alveolar nerve is directly positioned lingually to the tooth roots (p = 0.01). [ABSTRACT FROM AUTHOR]

Simple Summary: Teeth begin to grow in the jaws before birth and continue to appear in an overlapping sequence until each is complete in length. Subsequently, the central pulp (nerve) chamber of each tooth slowly fills in with dentine and the root of the tooth continues to accumulate thin layers of cementum until the individual dies. Each of the tooth tissues, the hard enamel cap, the dentine core of the tooth and the root cementum grow incrementally and incorporate small quantities of blood-born trace elements ingested from our diet into their structure. A chronological record of zinc incorporation exists in each tooth tissue and can be visualised in thin sections, or slices, of teeth using a beam of synchrotron light. Zinc markings in teeth are especially useful and occur at birth in enamel and dentine and annually in the cementum layers. This work shows that zinc is consistently concentrated within surface enamel and in the dentine surrounding the central pulp chamber. Knowing where to sample Zn in modern and fossil teeth enables us to reconstruct a chronology of growth and to determine something about diet in the past from the remnants of different Zn isotopes contained in different foodstuffs. Zinc is incorporated into enamel, dentine and cementum during tooth growth. This work aimed to distinguish between the processes underlying Zn incorporation and Zn distribution. These include different mineralisation processes, the physiological events around birth, Zn ingestion with diet, exposure to the oral environment during life and diagenetic changes to fossil teeth post-mortem. Synchrotron X-ray Fluorescence (SXRF) was used to map zinc distribution across longitudinal polished ground sections of both deciduous and permanent modern human, great ape and fossil hominoid teeth. Higher resolution fluorescence intensity maps were used to image Zn in surface enamel, secondary dentine and cementum, and at the neonatal line (NNL) and enamel–dentine–junction (EDJ) in deciduous teeth. Secondary dentine was consistently Zn-rich, but the highest concentrations of Zn (range 197–1743 ppm) were found in cuspal, mid-lateral and cervical surface enamel and were similar in unerupted teeth never exposed to the oral environment. Zinc was identified at the NNL and EDJ in both modern and fossil deciduous teeth. In fossil specimens, diagenetic changes were identified in various trace element distributions but only demineralisation appeared to markedly alter Zn distribution. Zinc appears to be tenacious and stable in fossil tooth tissues, especially in enamel, over millions of years. [ABSTRACT FROM AUTHOR]

Objective: Designed and applicated a modified customized CAD‐CAM socket‐shield preparation guide template in immediate implant and followed up for 3 years. Clinical Considerations: Socket‐shield technique could improve the esthetic effect of immediate implant restorations by preserving the labial fascicular bone‐periodontal complex at the implant site. While the socket‐shield technique is highly technique‐sensitive. A modified customized CAD/CAM guided template was designed and fabricated by 3D printing. The movement of the carbide bur during preparing the socket‐shield was limited by the socket‐shield preparation template. In this case report, the socket‐shield preparation template was used for preparing the socket‐shield in the tooth root with irregular morphology and the case was followed up for 3 years. Conclusions: The modified CAD/CAM socket‐shield preparation template effectively improved the accuracy and efficiency of preparing the socket‐shield by limiting the movement of the high‐speed carbide bur in both in both lip‐to‐palatal and crown‐to‐root orientation. The socket‐shield with accurate morphology could effectively maintain the gingival marginal level and contour. Clinical Significance: The modified CAD/CAM socket‐shield preparation template with the depth‐locking ring effectively reduced the technique sensitivity and time consumption of the socket‐shield technique, especially for tooth roots with irregular morphology. [ABSTRACT FROM AUTHOR]

Objective: To report a novel digital workflow to replace an anterior maxillary tooth lost due to trauma with an implant multilayer restoration by using the patient's extracted tooth as a final crown restoration using computer‐aided design/computer‐aided manufacturing (CAD/CAM) technology. Clinical Considerations: Instead of using the patient's natural tooth as an immediate provisional restoration to achieve predictable results in terms of esthetics and soft tissue structure, a novel digital strategy was performed to obtain a natural final crown restoration by using the patient's tooth associated with a lithium disilicate customized implant abutment. Conclusions: The perspective of using this strategic approach for implant restorative dental treatments in patients with traumatic root fractures in the anterior region has great potential as it helps to maintain the emergence profile of the natural dentition and esthetics. Clinical Significance: Optimal esthetic outcomes are challenging in implant dentistry regarding soft tissue structure and morphology factors. Using natural teeth from surgery to deliver the final restoration might be beneficial when an anterior tooth is lost due to trauma. [ABSTRACT FROM AUTHOR]

Objective: To assess the effect of different irrigating solutions (Normal saline, 5.25% NaOCl and 90% Ethanol) on apical sealing ability of resin based root canal sealer filled with single cone obturation technique in extracted teeth. Methods: From March 2022 to September 2022, the case control research was carried out at the Department of Operative Dentistry, Karachi Medical and Dental College in Karachi. Sample size of 30 single root teeth were decoronated and roots were divided into Group A and B. Group B is subdivided into two cases according to the type of irrigating solution used. Group A irrigation solutions include 5ml of Normal saline solution, while group B include 5ml of 5.25% Sodium Hypochlorite and 5ml of 90% Ethanol solution. Teeth were prepared, obturated, placed in 2% methylene blue dye and extent of dye penetration was done under a digital stereomicroscope and maximum leakage was measured by using software. Data was analyzed on SPSS version 26.0. Results: All solutions were normally distributed. While comparing both groups, Ethanol has the lowest mean value of dye penetration i.e. 1.07±0.63 which means that this irrigating solution has least micro leakage and provides effective seal of resin sealer to the root canal wall filled by using single cone obturating technique. Case group irrigation solutions has significant p-value i.e. 0.000 which indicates absolute absence of micro leakage. Upon Comparison of mean value of Sodium Hypochlorite and Ethanol, Ethanol is more efficient irrigation solution as it has shown lesser dye penetration as compared to Sodium Hypochlorite. Conclusion: It has been concluded that among all the solutions, Ethanol has proved to be the most effective irrigation solution followed by Sodium Hypochlorite, showed least dye penetration and hence least micro leakage. [ABSTRACT FROM AUTHOR]

A tegotheriid docodontan Sibirotherium rossicum from the Early Cretaceous of Western Siberia, Russia, was considered to have six lower premolars, as in the tegotheriids Agilodocodon and Microdocodon from the Middle Jurassic of China. The micro-computed tomography of two dentary specimens with a supposed submolariform ultimate deciduous premolar (dp6) revealed absence of a replacing tooth germ in this locus. Also, the morphology of the roots of this tooth is more consistent with that of molariform teeth. Based on the new data, we interpret Sibirotherium to possess five lower premolars rather than six and that the supposed dp6 might in fact be better interpreted as the first molariform (m1). The results of our phylogenetic analysis suggest that this is a plesiomorphic condition for Docodonta and, under slow character optimization, for Tegotheriidae, with the number of premolars reduced to three to four in Docodontidae (Haldanodon, Docodon, and Docofossor). [ABSTRACT FROM AUTHOR]