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Purpose: To investigate the cumulative survival rate (CSR) and marginal bone loss (MBL) of single implants immediately placed and restored with two-unit cantilevered fixed dental prostheses (FDPs) following the extraction of two adjacent mandibular incisors with a compromised periodontal condition. Materials and Methods: Patients in need of extraction and replacement of two adjacent mandibular incisors due to an advanced periodontal loss of attachment were treated consecutively. Following a flapless procedure, a single implant was placed at the time of extraction in one of the two fresh alveolar sockets and immediately restored with a screw-retained two-unit provisional FDP. The area of extraction was grafted using xenograft particulate material. The following elements were evaluated: the peri-implant soft and hard tissue condition at the last follow-up appointment, MBL at the last follow-up appointment at least 1 year after the delivery of the final prosthesis, and the final esthetic result. Results: A total of 20 patients were recruited between January 2014 and December 2019 in a single private practice. Each of them received a single implant and immediate provisional restoration with a two-unit cantilevered FDP. Patients were followed up for 22 to 94 months (average follow-up = 4 years) and none of the implants failed, resulting in a 100% CSR. The cumulative MBL--measured using the VixWin Platinum software--was 1.08 ± 0.35 mm. A lower MBL was observed in the presence of platform switching (0.63 ± 0.11 mm) compared to the absence of platform switching (1.27 ± 0.20 mm). Conclusions: The preliminary results obtained from this study suggest that patients who need to replace two adjacent periodontally compromised mandibular incisors can be treated with an immediately placed and restored single implant. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the extent of crestal bone loss (CBL) at 2, 12, 36, and 60 months in implants placed with the shoulder at the equicrestal level and 2 mm below the alveolar ridge. Materials and Methods: A split-mouth randomized controlled clinical trial was conducted by selecting subjects with a Kennedy Class IV partially edentulous mandible. Two implants of equal length and diameter were inserted, one equicrestal and the other subcrestal, in the lateral incisor sites. Using Rinn centering devices, intraoral periapical radiographs were taken at implant insertion (T0) and at 2 (T1), 12 (T2), 36 (T3), and 60 months (T4). Descriptive statistics and t test were used, with P = .05 considered statistically significant. Twenty-five patients were recruited, with a mean age of 65 ± 9.88 years (range: 42 to 82 years), and none dropped out. A total of 50 implants were inserted, 25 at the crestal level and 25 at the subcrestal level. Results: At the 60-month follow-up, no implant or prosthetic failure was recorded. An average CBL of 0.81 ± 0.40 mm (range: 0.1 to 1.6 mm) was recorded in the crestal implant group, while the subcrestal implants had an average CBL of 0.87 ± 0.41 mm (range: 0.2 to 2 mm); however, the higher CBL in the subcrestal group was not statistically significant (P = .65). Comparing the mean CBL of both groups at the various follow-ups, greater crestal bone resorption was recorded in subcrestal implants between T0 and T1 (0.25 vs 0.1 mm) and between T1 and T2 (0.39 vs 0.23 mm), while in subsequent follow-ups, a greater and statistically significant (P = .01) CBL was recorded in equicrestal implants between T3 and T4 (0.05 vs 0.18 mm). Conclusions: Thus, over time, the extent of CBL seems to be reduced in subcrestal implants, with bone retention above the implant shoulder. Although the position of the implant shoulder relative to the crestal ridge does not affect the CBL, subcrestal placement is recommended in order to reduce the risk of exposing the rough implant surface. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the occurrence, incidence rate, and esthetic impact of facial growth in adult patients who need a single implant rehabilitation in the central incisor area to assess the influence of time on changes in the incisal level. Materials and Methods: Patients were included if they received a single implant in the maxillary central incisor site, were at least 19 years old at the time of placement, and had natural adjacent teeth. Standardized images were obtained to evaluate the presence and incidence of incisal linear changes. All rehabilitations followed the same standard of reconstruction, while always keeping the mimetics of the homologous and adjacent tooth the same to provide the same incisal level and achieve the best esthetics for all patients. Thus, at implant placement (T0), the incisal-level difference between the crown and the adjacent tooth was zero. Any modifications in the incisal levels from 1.0 mm of difference were registered. This measurement of 1.0 mm was the cutoff mark because it permits easy observation of a difference, either by the dental professional or the patient. The data obtained were analyzed and correlated statistically. Results: A total of 56 patients and 56 implants were included (age range: 23-63 years; average age: 40.79 ± 12.25 years) in this study. Incisal-level alterations between the tooth and implant were found and had an incidence rate of 19.6%. The study had an average follow-up of 10.7 ± 3.37 years. All implants evaluated had stability and healthy peri-implant tissue conditions throughout the followup period, with a 100% survival rate. There was no statistically significant prevalence of incisal-level changes between males (19%) and females (20%) (P = .238); the incidence rate was 41.7% for patients between 20 and 30 years old, 13.3% for patients between 31 and 40 years old, 23.7% for patients between 41 and 50 years old, and 6.3% in the group over 50 years old; note that there were no statistically significant differences (P = .118) among different age groups. Similarly, no statistically significant difference was observed (P = .262) comparing the number of clinical cases in each subgroup with and without change in the incisal level. Conclusions: Changes in the incisal level of maxillary anterior crowns retained by single implants in adult patients were present in 19.6% of the cases evaluated. This prevalence was not influenced by sex or age group; however, it was observed more often in dental implant cases with longer follow-ups. [ABSTRACT FROM AUTHOR]

The purpose of this retrospective study was to assess facial and palatal alveolar wall thickness (AWT) in relation to sagittal root position (SRP) of maxillary anterior teeth using CBCT. A total of 102 CBCT images (60 women, 42 men) of maxillary anterior teeth were reviewed. SRP was classified according to Kan's classification, and AWT was evaluated at coronal (4 mm from the CEJ), mid-root, and apical (2 mm from the apex) levels of the facial and palatal aspects. Sex, age, and tooth type were analyzed as secondary variables. The SRP distribution was 76.6% class I, 11.3% class II, 0.8% class III, and 11.3% class IV. AWT, from thickest to thinnest, was found in palatal apical, then mid-root, then coronal levels, followed by facial coronal, then mid-root, then apical levels. AWT was thickest in SRP class II, followed by classes I and III, and least thick in class IV at all measured areas (P < .05). A significantly higher AWT was associated with class I in central incisors, class II in canine teeth and in men, and class IV in central incisors and canines. [ABSTRACT FROM AUTHOR]

Purpose: To perform a finite element analysis (FEA) and an in vitro experiment to investigate and compare the loading effects (effects on the implant and surrounding bone) of various customized angled abutments to commercial 15-degree angled abutments (control). Materials and Methods: Four customized angled abutment models (21.9, 24.15, 20.22, and 33 degrees) were developed using CBCT images of incisor inclination measurements from patients of various age groups (20 to 23, 24 to 39, and 40 to 65 years). 3D maxillary bone models were created from the CBCT images of four individual patients: One patient from each age group with the respective average incisor inclination measurement and another patient with the overall average were selected. Then, FEA and in vitro strain gauge experiments were conducted by applying 100 N or 50 N of axial or oblique force to each model in order to assess the differences in stress/strain between the customized angled abutments (test) and the control in both the implants and surrounding bone. Results: Under axial loading, the stress values in the implant and surrounding bone were elevated due to the relatively higher angles of the customized angled abutments (21.9, 24.15, 20.22, and 33 degrees) compared to the control angled abutments. Under oblique loading, the control angled abutments exhibited higher stress values in both the implant and surrounding bone. For the in vitro experiment, there was no statistically significant difference in bone strain between the customized (21.9 degree) and the control angled abutments in axial loading. Nevertheless, the control angled abutment with oblique loading induced greater bone strains. Conclusions: Customized angled abutments offer lower stress/strain under oblique loads but higher stress/strain under axial loads compared to the control abutments. Therefore, in the design and application of angled abutments, careful consideration of the occlusal load direction is important for achieving the biomechanical success of an implant. [ABSTRACT FROM AUTHOR]

Objective: This prospective case series aimed to clinically evaluate the bleaching effect, spontaneous tooth sensitivity, and variation in the thermal sensation threshold of different groups of teeth undergoing in-office bleaching. Method and materials: Ten patients received conventional bleaching treatment: 35% hydrogen peroxide with three bleaching sessions of 45 minutes, evaluating color change (ΔE and ΔE00), Whitening Index (WID), and tooth sensitivity (visual analog scale). Thermal stimulus-generating devices were used to simulate sensitivity caused by low temperatures through quantitative sensory tests. Analyses were conducted individually on different teeth groups (n = 20) (mandibular incisors, maxillary incisors, canines, maxillary first premolars). Results: Regarding color change, mandibular and maxillary incisors did not statistically differ from each other but showed significant difference and greater bleaching potential compared to canines and maxillary first premolars (P = .018). Regarding sensitivity, mandibular and maxillary incisors presented the highest spontaneous sensitivity values (P = .032), while maxillary first premolars did not display painful symptoms, also observed in provoked sensitivity analysis (P = .025). Conclusions: The general analysis of the results indicates that the tooth type affects the response to the whitening treatment, both in relation to the esthetic benefit and the occurrence of tooth sensitivity. It was observed that mandibular incisors reach the degree of chromatic saturation before canines and premolars, in addition to presenting greater bleaching sensitivity. Personalizing the treatment, based on prior knowledge of the degree of saturation, anatomical factors, and the risk of sensitivity, can provide considerable advantages in the whitening technique. [ABSTRACT FROM AUTHOR]

The interforaminal region is considered more favorable for implant placement than the posterior mandible in edentulous patients, mainly because the inferior alveolar nerve can interfere with implant placement in the severely resorbed posterior mandible. However, complications in the interforaminal region may occur due to the presence of the mandibular incisive nerve. This scoping review aims to describe the mandibular incisive nerve anatomy related to the potential interference in implant therapy. A comprehensive literature search was conducted in the following databases: MEDLINE (via PubMed), Web of Science, and Scopus. This scoping review was structured according to the Joanna Briggs Institute method. Thirteen studies were included in the review. All of the studies were observational cohort anatomical studies, carried out mainly by CBCT and on cadavers. A total of 1,471 patients/cadavers were studied. The mandibular incisive nerve was present in 87% to 100% of cases, with an average length of 9.97 mm and an average diameter of 1.97 mm. The mandibular incisive nerve may be damaged during drilling and implant placement, especially when using implant lengths > 12 mm. Damage to the mandibular incisive nerve due to implant placement could be present, but it is necessary to conduct more studies focusing on assessing mandibular incisive nerve damage to understand the clinical relevance of this nerve and its associated morbidities, such as neurosensorial alterations. Due to the different anatomical characteristics of this nerve, CBCT analysis is recommended for implant therapy in the anterior mandible to prevent the described complications. [ABSTRACT FROM AUTHOR]

Purpose: To investigate the influence of a single infrapositioned ankylosed tooth or implant-supported restoration on smile esthetics. Materials and Methods: A series of 48 digitally modified images that simulated varying degrees of infraposition (from 0.25 to 2.0 mm, with a step of 0.25 mm) were created for each maxillary anterior tooth by altering the full-portrait image of a smiling man, adjusted to show medium and high smile lines. For the model with the high smile line, a series of 24 digitally modified images were created that simulated the infraposition of a single anterior tooth with a restored incisal edge. Smile esthetics for each of the images were evaluated by 160 participants (80 dentists and 80 laypersons), and a visual analog scale (VAS) was implemented. Results: For the images with the high smile line, an infraposition of ≥ 0.25 mm in the central incisor region and ≥ 0.5 mm in the region of the lateral incisor or the canine had a negative effect on the perceived smile esthetics for both the dentists and the laypersons. Regarding the medium smile line, an infraposition of ≥ 0.5 mm in the central and lateral incisor region had a negative effect on the perceived smile esthetics for both groups of observers. In the canine area, an infraposition of ≥ 0.5 mm for the dentists and ≥ 0.75 mm for the laypersons also had a negative impact on the smile esthetics. Conclusions: Even a minor infraposition of a single maxillary anterior ankylosed tooth or implant-supported restoration can reduce the perceived attractiveness of the smile. Infraposition in the canine site can be better tolerated in a medium smile line compared to a high smile line. In patients with a high smile line, prosthetic intervention is needed to restore the incisal edge of an infrapositioned tooth without harmonizing the gingival contour; this can be beneficial for the lateral incisor but ineffective for the central incisor and unfavorable for the canine. [ABSTRACT FROM AUTHOR]

Implants with deficient papillae and black triangles are common findings. The treatment of these esthetic complications is considered to be challenging with limited predictability. Therefore, the present report aims to describe a novel technique for papilla augmentation: the "iceberg" connective tissue graft (iCTG) after extraction and interproximal bone reconstruction in the anterior region. A 35-year-old patient presented with a hopeless tooth with interproximal clinical attachment loss extending to the apical third of the adjacent tooth. Interproximal bone reconstruction was performed through alveolar ridge preservation by directly applying recombinant human platelet-derived growth factor-BB (rhPDGF-BB) to the exposed root surface of the adjacent tooth. A mixture of autogenous bone chips (obtained from the ramus) and bovine bone xenograft particles (previously mixed with the growth factor) was also used. The patient was able to return for implant therapy only 2 years later, at which time an incomplete regeneration of the interproximal bone was observed. Therefore, to compensate the interproximal deficiency, the iCTG approach was utilized, involving a double layer of CTG with different origins. Two small grafts from the tuberosity were sutured to the mesial and distal ends of a wider CTG harvested from the palate, aiming to gain additional volume at the interproximal sites. The composite graft was then sutured on top of the implant platform, and the flap was then released and closed by primary intention. After conditioning the peri-implant tissues, the case was finalized with a satisfactory outcome. The described iCTG could be an effective approach for reconstructing peri-implant papillae following interproximal bone reconstruction. [ABSTRACT FROM AUTHOR]

Purpose: To assess whether a health education video increased prosthodontic treatment demand for replacing missing teeth compared to a traditional health education (IEC) leaflet among patients visiting a university dental care center in Saudi Arabia. Materials and Methods: A nonrandomized educational intervention was conducted among patients with missing teeth. A total of 350 participants were divided equally into two health-education intervention groups: leaflet group and video group. Two major variants were ascertained: demand for prosthodontic dental care and awareness (knowledge) about the importance of replacing missing teeth. These two variants were studied for the difference in the scores between base line and at the end of the program (after 3 months). Bivariate analysis was done with chi-square test, McNemar chi-square test, and Wilcoxon matched-pairs tests, and finally binary logistic regression analysis was done. Results: The final analysis included 324 participants. There was improvement in both knowledge and demand for prosthodontic care in both the groups after health education, but a statistically significant improvement in demand for dental care was observed in the video group compared to the leaflet group (42.9% vs 63.2%). Logistic regression analysis identified that missing teeth in the anterior region and being in the video group were two significant factors associated with increased demand for care. Conclusions: The health education video method was found to be a more effective method compared to leaflets in improving knowledge and demand for replacing missing teeth. [ABSTRACT FROM AUTHOR]

Dental implants are commonly used to replace missing single teeth. However, esthetic rehabilitation of an adjacent tooth may also be required due to diastemas, crowding, or existing large direct restorations to improve the final esthetic outcome. With the advancements in ceramics and bonding techniques, minimally invasive esthetic approaches have become viable for compromised spacing issues. This case report describes a dental technique for the esthetic rehabilitation of compromised anterior spacing with a customized zirconia implant abutment at a maxillary central incisor site and a partial ceramic veneer bonded to the adjacent central incisor. [ABSTRACT FROM AUTHOR]

Purpose: To validate an innovative 3D volumetric method of evaluating tissue changes proposed by Lee et al in 2020 by comparing the results of this method--in which the scanned peri-implant surfaces were transformed, visualized, and analyzed as 3D objects--to the results reported by an existing method based on calculation of the mean distance between measured surfaces. The null hypothesis was that there was no statistically significant difference between the two methods. Additionally, the present study evaluated peri-implant tissue changes 5 years after single implant placement in the esthetic zone. Materials and Methods: Both methods were applied to 11 oral implant site casts (6 maxillary central incisor sites, 5 maxillary lateral incisor sites) taken from 11 patients at crown placement and at follow-up examinations 5 years later. The methods are based on digital workflows in which the reference and 5-year casts are scanned and the resulting STL files are superimposed and analyzed for three regions of interest (mesial papilla, central area, and distal papilla). The volumetric changes reported by the Lee et al method and the mean distance method were calculated and compared using the Spearman rank correlation coefficient (P < .01) and the Wilcoxon signed-rank test (P < .05). Results: The correlation between the two sets of measurements was very high (Spearman rank correlation coefficient = 0.885). The new volumetric method indicated a mean volume loss of 2.82 mm3 (SD: 5.06), while the method based on the measurement of mean distance showed a mean volume loss of 2.92 mm3 (SD: 4.43; Wilcoxon signed-rank test result: P = .77). No statistically significant difference was found. The two methods gave equivalent results, and the null hypothesis was accepted. Conclusions: The new volumetric method was validated and can be considered a trustworthy tool. [ABSTRACT FROM AUTHOR]

Purpose: To study the influence of tooth mobility on the accuracy of conven6onal impressions. Materials and Methods: In total, 10 pa6ents with mobile anterior teeth and 10 healthy pa6ents were treated with conven6onal impressions and intraoral digital impressions. The digital impression group was recorded as standard data, the mobile teeth group was recorded as the experimental group, and the healthy anterior teeth group was recorded as the control group. We imported digital impression and irreversible hydrocolloid impression files into Geomagic Wrap and marked reference points to execute N-point alignment, then we recorded the coordinates. Paired-samples t test was used to analyze whether the point coordinates of mobile teeth were statistically significant (α = .05). One-way ANOVA was used to analyze whether there was a rela6onship between coordinate differences and tooth mobility in the distal, coronal, and buccal directions (α = .05). Results: In the buccal and coronal directions, the difference was statistically significant between the conven6onal and digital impression groups. In the buccal direction, the accuracy differences of I-degree and II-degree mobile teeth were 0.149 mm and 0.401 mm, respectively. In the coronal direction, the differences were 0.128 mm and 0.233 mm, respectively. Meanwhile, ANOVA analysis showed that there was a rela6onship between point coordinate difference and tooth mobility in the buccal and coronal directions. Conclusions: Conventional impressions can influence the accuracy of mobile tooth impressions. Therefore, digital impressions should be adopted for mobile teeth impressions. [ABSTRACT FROM AUTHOR]

The aim of this study was to present a periodontal plastic surgery approach to treat gingival recessions (GRs) and correct mandibular incisor mucogingival conditions and deformities. Isolated deep GRs (≥ 3 mm) in the mandibular incisors (n = 24 teeth) were treated: 66.6% of sites were recession types 2 or 3, and 58.3% of teeth were malpositioned. Recessions were treated using free mucogingival grafts (FMGs) harvested from the buccal aspect of donor teeth with altered passive eruption or healthy periodontal support, with < 3 mm between the cementoenamel junction and the buccal alveolar crest. Clinical parameters (GR, clinical attachment level, interproximal papilla tip location, keratinized tissue, vestibule depth) and root coverage esthetic score were evaluated at 9 months. FMG significantly reduced GR (P < .001) and increased keratinized tissue (P < .001) without loss of vestibule depth (P > .05). Mean root coverage was 94.37% ± 10.60%, mean residual GR was 0.08 ± 0.65 mm, and the mean root coverage esthetic score was 8.9 ± 1.24. Recession types 2/3 showed significant interproximal clinical attachment gain (P < .05). The interproximal papilla was significantly augmented at sites with papilla loss (P < .001). No clinical attachment loss (P = .346) was detected at donor sites. These results suggest that FMG is a promising root coverage approach for recession types 1, 2, and 3, correcting mucogingival conditions and deformities and reconstructing the interproximal papilla. [ABSTRACT FROM AUTHOR]

The article discusses a case report on a digital and interdisciplinary adhesive conservative rehabilitation approach for a young patient with dental structure loss. The treatment focuses on integrating esthetic and occlusal parameters using restorative materials and digital tools. The interdisciplinary approach involves restorative dentistry, orthodontics, and prosthodontics to achieve a successful outcome. The treatment plan includes periodontal therapy, nonanatomical biologic reconstruction, clear aligner therapy, and sectorized ceramic restorations. The article emphasizes the importance of a smooth integration between esthetic and occlusal parameters in conservative oral rehabilitation. [Extracted from the article]

Purpose: Part 2 of this German S3 clinical practice guideline provides recommendations for the process of manufacturing composite restorations. It covers key aspects like caries removal, field isolation, matrix and adhesive techniques, as well as light curing and polishing. The outcomes of interest include survival rates and restoration quality. Materials and Methods: A systematic literature search was conducted by two methodologists using MEDLINE and the Cochrane Library via the OVID platform, including studies up to December 2021. Additionally, the reference lists of relevant manuscripts were manually reviewed. Six PICO questions were developed to guide the search. Consensus-based recommendations were formulated by a panel of dental professionals from 20 national societies and organizations based on the collected evidence and expert opinion. Results: The guideline advocates for one-stage selective caries removal near the pulp and underscores the effectiveness of various isolation techniques, adhesive systems, and the crucial role of light polymerization. The use of anatomically preformed sectional matrices and phosphoric acid etching is recommended to enhance restoration quality. Additionally, polishing composite restorations is advised to improve surface finish. Conclusion: This guideline provides comprehensive recommendations that inform clinicians on optimizing the composite restoration manufacturing processes. The adoption of these best practices can improve the quality and longevity of dental restorations. [ABSTRACT FROM AUTHOR]

Purpose: This German S3 clinical practice guideline offers evidence-based recommendations for the use of composite materials in direct restorations of permanent teeth. Outcomes considered were the survival rates and restoration quality and process quality of the manufacturing process. Part 1 of this two-part presentation deals with the indication classes. Materials and Methods: A systematic literature search was conducted by two methodologists using MEDLINE and the Cochrane Library via the OVID platform, including studies up to December 2021. Six PICO questions were developed to guide the search. Recommendations were formulated by a panel of dental professionals from 20 national societies and organizations based on the collected evidence. Results: Composite materials are a viable option for the direct restoration of cavity Classes I-V and may also be used for restorations with cusp replacement, and tooth shape corrections. In the posterior region, direct composite restorations should be preferred over indirect composite inlays. For Class V restorations, composite materials can be used if adequate contamination control and adhesive technique are ensured. Conclusion: The guideline is the first to provide comprehensive evidence on the use of direct composite materials. However, further long-term clinical studies with comparators such as (modified) glass-ionomer cements are necessary. Regular updates will detail the future scope and limitations of direct composite restorations. [ABSTRACT FROM AUTHOR]

Purpose: To determine the influence of partial edentulous distal extension and the use of removable partial dental prostheses in partially edentulous areas on the force exerted on the anterior teeth. Materials and Methods: A total of 83 volunteer patients participated in this study. The occlusal force was measured using an occlusal force measuring sheet in the patient's mouth. The occlusal forces and ratios were compared using the Wilcoxon signed-rank test (P < .05). Results: The force exerted on the anterior teeth increased significantly as the number of remaining teeth decreased in an edentulous distal extension. The force exerted on the anterior teeth decreased significantly with the use of a removable partial dental prosthesis. Conclusions: In a clinical setting, when the number of remaining teeth in a partial edentulous distal extension decreases, the burden on the anterior teeth increases. Our findings suggest that, for patients with partial edentulous distal extension, using a removable partial dental prosthesis is effective in preserving the residual anterior teeth by reducing excessive force. [ABSTRACT FROM AUTHOR]

Gait stability and walking direction control are conventionally attributed to coordination among somatosensory, visual, and vestibular systems. Recent evidence of functional interdependence between masticatory and neuromuscular systems indicates that the stomatognathic system is neurologically integrated with various body systems relevant to movement planning and execution. This study investigated the effects of unilateral molar biting and incisor biting on walking with and without visual feedback. A cohort of 31 healthy young adults aged 21 to 30 years (average age of 23.93 ± 1.89) participated in this study. Three types of errors in walking direction (angle error, position error, and curve error) were computed. Our findings indicate that, in right-handed individuals, irrespective of visual feedback, unilateral biting caused systematic deviations toward the biting side from initiation to termination of walking. The consistent deviation in walking, particularly during unilateral right biting conditions in right-handed individuals, may indicate a complex interplay between masticatory function and gait control mechanism, potentially influenced by handedness and motor lateralization within the cortex. This study establishes a foundation for future research exploring the interrelation between bite location, visual feedback, and motor control in diverse populations. This research may provide insight for more efficient interventions for gait-related disorders. [ABSTRACT FROM AUTHOR]

We present the first records of Linichnus (cf. Linichnus serratus and L. bromleyi), as well as Nihilichnus sulcatus in the Itaboraí Basin, Brazil. The studied specimen, an incomplete left dentary of the metatherian Guggenheimia crocheti, displays a long, wide groove with a discrete serrated edge, suggestive of Linichnus serratus; a long, narrow, smooth-edged, Linichnus bromleyi, and three pairs of Nihilichnus sulcatus. The placement of the N. sulcatus perforations and grooves support tooth slippage as the mechanism for producing this ichnospecies. The studied ichnotaxa could only be produced by Epidolops ameghinoi, a polydolopimorphian metatherian characterized by plagiaulacoid third premolars, which are large teeth with a serrated longitudinal blade, hypertrophied and semi-procumbent lower incisors and lower canines, and complex chewing kinetics. Sebecids are ruled out due to the presence of N. sulcatus, a single shallow, long, 'U-shaped' groove, and a single, long L. bromleyi, plus the absence of Knethichnus parallelum, 'V' marks, Nihilichnus sicarius, and crushed bone. Consequently, the pattern of the studied specimen is opposite to that inferred to have been produced by sebecids. These traces represent the first record during the Paleogene of South America of Linichnus being produced by a land mammal like Polydolopimorphia. These observations support scavenging behaviour for E. ameghinoi. [ABSTRACT FROM AUTHOR]

Objective: This study aims to evaluate the incidence of open gingival embrasures (OGES) after orthodontic treatment and analyze its correlation with various clinical and radiographic parameters. Methods: We retrospectively analyzed 330 orthodontic patients at West China Hospital of Stomatology from 2016 to 2023, categorizing them into Non-OGES (200) and OGES (130) groups based on post-treatment OGES presence in the central incisor area. Basic information of patients, pre- and post-treatment lateral cephalometric radiographs, and cone-beam computed tomography (CBCT) data were collected. Chi-square tests, two-sample t-tests, Welch's t-tests, and Mann–Whitney U tests were used to compare differences in gender, initial age, treatment duration, and cephalometric and CBCT indicators between the two groups. Binary logistic regression analysis was further employed to explore the clinical characteristics and cephalometric indicators of the study population. Results: Univariate analysis revealed that the occurrence of maxillary central incisor OGES was significantly correlated with gender, initial age, treatment duration, and related cephalometric and CBCT indicators (P < 0.05). Similarly, the occurrence of mandibular central incisor OGES was also significantly associated with gender, initial age, treatment duration, and specific cephalometric changes (P < 0.05). Binary logistic regression analysis indicated that the occurrence of maxillary central incisor OGES was significantly related to initial age, treatment duration, and the change in the U1-SN angle, while the occurrence of OGES in the mandibular central incisor area was mainly related to initial age and treatment duration. Conclusion: Orthodontic treatment plans should consider a variety of influencing factors, including initial age, treatment duration, anterior tooth angle and position, root-bone relationship, and the distance from the anterior tooth contact point to the alveolar crest, to prevent or reduce the occurrence of OGES after orthodontic treatment, thereby improving patients' aesthetic outcomes and periodontal health. [ABSTRACT FROM AUTHOR]

Objectives: This study aimed to develop a cephalometric classification method based on multitask learning for eight diagnostic classifications. Methods: This study was retrospective. A total of 3,310 lateral cephalograms were collected to construct a dataset. Eight clinical classifications were employed, including sagittal and vertical skeletal facial patterns, maxillary and mandibular anteroposterior positions, inclinations of upper and lower incisors, as well as their anteroposterior positions. The images were manually annotated for initially classification, which was verified by senior orthodontists. The data were randomly divided into training, validation, and test sets at a ratio of approximately 8:1:1. The multitask learning classification model was constructed based on the ResNeXt50_32 × 4d network and consisted of shared layers and task-specific layers. The performance of the model was evaluated using classification accuracy, precision, sensitivity, specificity and area under the curve (AUC). Results: This model could perform eight clinical diagnostic classifications on cephalograms within an average of 0.0096 s. The accuracy of the six classifications was 0.8–0.9, and the accuracy of the two classifications was 0.75-0.8. The overall AUC values for each classification exceeded 0.9. Conclusions: An automatic diagnostic classification model for lateral cephalograms was established based on multitask learning to achieve simultaneous classification of eight common clinical diagnostic items. The multitask learning model achieved better classification performance and reduced the computational costs, providing a novel perspective and reference for addressing such problems. [ABSTRACT FROM AUTHOR]

Understanding root canal morphology is essential for successful endodontic treatment. This study aimed to investigate morphological variations in root and canal systems of anterior and premolar teeth across different age groups and genders in a Saudi Arabian subpopulation using a novel classification system. A total of 3573 maxillary and mandibular anterior and premolar teeth in 209 patients were examined using cone-beam computed tomography (CBCT) in a Saudi subpopulation. The number of roots was identified, and root canal configurations were classified according to Ahmed et al. coding system (Int Endod J 50(8):761–770, 2017). Demographic data including gender (male and female) and age (divided into 6 groups—10–20, > 20–30, > 30–40, > 40–50, > 50–60, > 60–70) were recorded. The Chi-square test was used for statistical analysis, and the significance level was set at 0.05 (P = 0.05). Results showed that maxillary and mandibular central incisors, lateral incisors, and canines predominantly exhibited the 1TN1 configuration. Maxillary first premolars had a higher prevalence of double-rooted variants with code 2TN B1 P1. Maxillary second premolars more frequently displayed the 1TN1–2−1 configuration. No significant gender and age differences were observed in maxillary anterior and premolar teeth (p > 0.05). A number of supplemental configurations such as 2TNB1–2P1, 3TN MB1 DB1 P1, and 3TN 1(MB1 DB1) P1 were noted in maxillary premolars. For mandibular anteriors, results showed no significant difference by gender, but for age, mandibular incisors showed more prevalence of complex canal configurations up to 40 years. However, the difference with other age groups (> 40–70 years) was not statistically significant (p < 0.05). For mandibular premolars, the code 1TN1 was observed in more than 90% of the teeth with no significant differences in gender and age groups (p > 0.05). Several supplemental configurations such as 1TN1–2−3, 1TN1–2−3−2, 2TN B1/L1, and 2TN 1B1/L1) were noted in mandibular first premolars. This study identified a wide range of root and canal anatomical variations in anterior and premolar teeth within a Saudi subpopulation. The findings revealed that while age influenced the complexity of root canal systems in mandibular incisors, no significant association between gender and canal complexity was observed. The Ahmed et al. classification system offered a detailed analysis of these complex variations, providing a clear understanding of the root canal morphology in this population. [ABSTRACT FROM AUTHOR]

Objective: This thesis aims to digitally study the natural longitudinal evolution of clinical crown height in maxillary and mandibular central incisors and first molars between 8 and 18 years of age. Methods: A total of 31 subjects (17 females and 14 males) were selected for the study. Their plaster study models were converted to digital format using a three-dimensional scanner. Digital anatomical landmarks were placed on the central incisors and first molars of all dental arches. The clinical crown height of the central incisors and first molars was then analyzed digitally and longitudinally, based on the position of the marginal gingiva on the vestibular surface of the teeth in question. Results: The clinical crown height of maxillary and mandibular central incisors and first molars increased significantly with age (p-value < 0.001) from 8 to 18 years. On average, the clinical crown height increased by 1.5 mm for the upper central incisors and 0.8 mm for the mandibular central incisors. The clinical crown height of the upper first molar increased on average by 2.7 mm and 2.1 mm for mandibular first molars. Conclusions: The clinical crown height of maxillary and mandibular central incisors and first molars appears to continue increasing beyond 18 years of age. These results suggest that the position of the marginal gingiva on the buccal surface of the teeth is not stable at 18 years of age. [ABSTRACT FROM AUTHOR]

Collagen fibers of the Periodontal ligament (PDL) play a crucial role in determining its mechanical properties. Based on this premise, we investigated the effect of the volume fraction of human PDL collagen fibers on the hyperelastic mechanical behavior under transient loading. Samples were obtained from different root regions (neck, middle, and apex) of the PDL, prepared from fresh human anterior teeth. The collagen fibers volume fraction in various regions of the PDL was quantified by staining techniques combined with image processing software. The collagen fiber volume fractions were found to be 60.3% in the neck region, 63.1% in the middle region, and 52.0% in the apex region. A new hyperelastic constitutive model was constructed based on the volume fraction. A uniaxial tensile test was conducted on these samples, and the accuracy of the constitutive model was validated by fitting the test data. Also, relevant model parameters were derived. The results demonstrated that human PDL exhibited hyperelastic mechanical properties on the condition of transient loading. With an increase in the volume fraction of collagen fibers, the tensile resistance of the PDL was enhanced, demonstrating more significant hyperelastic mechanical properties. The hyperelastic constitutive model showed a good fit with the experimental results (R2 > 0.997), describing the hyperelastic mechanical properties of the human PDL effectively. [ABSTRACT FROM AUTHOR]

Purpose: This study aimed to determine the prevalence of hypomineralised second primary molars (HSPM) and molar incisor hypomineralisation (MIH) in cleft lip and/or palate (CL/P) patients. Methods: A retrospective analysis of intraoral photographs of CL/P patients was done. All patients born between 2000 and 2011, and visiting the cleft team of the Erasmus Medical Center in Rotterdam, The Netherlands, were included. Their photos were scored on the presence and severity of HSPM and MIH using criteria formulated by the European Academy of Pediatric Dentistry. The outcomes were compared with data of the general population, extracted from the Generation R study. Results: The photos of 535 CL/P patients were evaluated. The overall prevalence of HSPM in CL/P patients was 15.2%, of MIH 12.8%. HSPM and MIH prevalence was significantly higher (both p < 0.001) compared to prevalence in the general population. No significant differences were found in prevalence of HSPM nor of MIH in CL/P patients based on gender (p = 0.891 resp. p = 0.405), cleft type (p = 0.282, resp. p = 0.415), Pierre Robin (p = 0.837, resp. p = 0.169) or other comorbidities (p = 0.553, resp. p = 0.617). CL/P patients with HSPM were almost 3 times more likely diagnosed with MIH than CL/P patients without HSPM (OR = 2.57, p = 0.002). Conclusion: The prevalence of HSPM and MIH is higher in patients with CL/P than in the general population. [ABSTRACT FROM AUTHOR]

Background/Objectives: Orthodontic treatment offers significant functional and aesthetic benefits, but it often causes discomfort, impacting patients' daily activities, including diet and medication use. The primary aim of this observational study was to assess the influence of orthodontic patients' age, gender, and living environment on pain duration, diet impairment, and analgesic use one week after their first adjustment visit to the orthodontist. Methods: This observational study included a sample of 194 orthodontic patients who completed a questionnaire consisting of six single-choice questions. The questions addressed the following variables: age, gender, living environment, pain duration, diet impairment, and analgesic use. The main inclusion criteria encompassed undergoing fixed orthodontic treatment on the upper arch for one week using a 0.0016-inch superelastic NiTi archwire (American Orthodontics, Sheboygan, WI, USA) and presenting moderate to severe crowding of the upper and lower anterior teeth. Results: Female patients were significantly more likely to experience diet impairment than males (51.9% vs. 33.3%, p = 0.013). Among female patients reporting pain lasting approximately one week, a higher proportion resided in rural areas (25% vs. 6.8%, p = 0.045), whereas male patients reporting the same pain duration predominantly lived in urban areas (12.5% vs. 0%, p = 0.028). Overall, 55.7% of participants used analgesics, with females in rural areas being the most frequent users. Additionally, patients who used analgesics were significantly more likely to experience diet impairment than those who did not (64.3% vs. 49.1%, p = 0.041). Conclusions: Female patients residing in rural areas reported a longer duration of pain, which led to a greater likelihood of experiencing diet impairment and increased consumption of analgesics compared to their counterparts. These findings highlight the need for personalized pain management strategies in orthodontic treatment, especially for patients with increased vulnerability to discomfort. [ABSTRACT FROM AUTHOR]

Background and Objectives: Gingival recession is a common periodontal condition that can lead to aesthetic and functional problems if untreated, necessitating the development of effective root coverage techniques. The aim of this study was to compare two different root coverages for localized gingival recession on the lower anterior teeth using a partially de-epithelialized connective tissue graft (PE-CTG). Materials and Methods: This study included 18 patients (20 teeth) with lower anterior tooth recession. In the tPECTG group (seven patients, eight teeth), the recipient site was prepared with supraperiosteal tunneling. In the vPECTG group (11 patients, 12 teeth), the recipient site was prepared using the vestibular incision subperiosteal tunnel access technique. In both groups, partially de-epithelialized connective tissue was harvested from the hard palate using a high-speed handpiece diamond burr. The change in root coverage was evaluated based on vertical recession and keratinized tissue (KT) values before surgery and 6 months after surgery. Results: The mean root coverage was 89.01% across all cases, with the tPECTG and vPECTG groups achieving 87.85% and 89.78%, respectively. The average KT gain was 3.48 ± 1.37 mm, with the tPECTG group showing 3.94 ± 1.74 mm and the vPECTG group showing 3.17 ± 1.03 mm. No significant differences were found between the two groups for either parameter (p > 0.05). Conclusions: Within the limitations of this retrospective case series, vPECTG was as effective as tPECTG, but easier. Moreover, in both groups, the keratinized gingival width increased, and the mucogingival junction was maintained. [ABSTRACT FROM AUTHOR]

Aim: Evaluate constitutional differences in chin morphology and volume, and mandibular tooth size, between different facial divergence patterns. Materials and Methods: The sample consisted of 284 pretreatment cone beam computed tomography (CBCT) images of growing and non‐growing patients who were stratified into 4 groups based on mandibular plane inclination to cranial base (SN) angle. Linear and angular measurements were made on the lateral CBCT images: mandibular lateral incisor crown (I‐C) total (I‐A) lengths, the distances between point D (centre of symphysis) and both incisor apex (D‐A) and menton (D‐Me) and between cemento‐enamel junction and menton (CEJ‐Me); chin width at the level of the central incisor apex (CWA) and point D (CWD); and the angles of the anterior and posterior symphyseal slopes. The volume of the symphysis was measured using a specialized 3D imaging software. Group differences and associations between parameters were gauged through the three‐way ANOVA analysis. Results: I‐C, I‐A, D‐A, D‐Me and CEJ‐Me were greater in the hyperdivergent group (p <.001). CWA and CWD were wider in the hypodivergent group (p =.003). Volume of the chin and inter‐slope angles were similar in all groups (p >.05). The anterior slope angle decreased with hyperdivegence (p <.005) in opposite pattern to the posterior slope angle (p <.005). Conclusions: Shape differences in mandibular symphysis were observed between opposite divergence patterns. Mandibular incisors were longer with hyperdivergence and shorter with hypodivergence. However, chin volumes were similar across divergence groups. These findings underline the role of genetic and environmental factors that impact facial growth. [ABSTRACT FROM AUTHOR]

Objective: The present clear aligner therapy (CAT) research focuses on isolating and reporting the biomechanical performance for three separate teeth, three translational movements and two flat trimlines at different heights. By identifying key patterns, the research seeks to inform the development of improved aligner designs, ultimately enhancing the effectiveness of clinical orthodontic treatments. Materials and Methods: In an in vitro setting using the Orthodontic Force Simulator (OFS), the biomechanical response of 30 aligners was investigated on three different teeth of a straight symmetric maxillary dentition (central incisor, canine and first molar). Each tooth was tested under two flat trimline conditions (trimmed at gingival margin, TL0; extended 2.0 mm below, TL2) and for three types of translational movements (palatal translation, mesial translation and intrusion). Forces and moments were reported at the centre of resistance for each displaced tooth as well as the two neighbouring teeth, evaluating a total of 18 distinct scenarios. Results: Findings indicate significant variability in the biomechanical responses based on tooth location in the arch, trimline height and movement performed. For palatal translations, the palatal force required to perform the movement was observed highest in molar cases, followed by canine and incisor cases, with a notable difference in the distribution of side effects, indicating a strong influence of tooth anatomy and position in the arch. Similarly, in mesial translations and intrusions molars experienced greater forces and moments than the corresponding movements applied on canines and incisors, but uniquely dispersed for each configuration tested. Regarding the shape of the aligner, TL2 consistently showed improved control over orthodontic movements compared to TL0. Neighbouring teeth frequently displayed compensatory reactions up to about half of the intensity observed on the tooth being moved, with notable variations from case to case. Conclusions: This research supports fundamental factors impacting CAT: Characteristic patterns in the direction and intensity of forces and moments are associated with each of the three translational movements tested.Tooth anatomy and arch location significantly influence the biomechanical performance of aligners, with an observed trend for molars to display higher forces and moments over canines and incisors, but distributed differently.The height of a flat trimline, specifically TL2, shows enhanced control over orthodontic movements.Additional findings revealed a compensatory activity of neighbouring teeth, which varies based on tooth region and movement type. It potentially could influence CAT outcomes negatively and merits attention in future investigations. These results support a tailored CAT method that improves aligner design for better force application. This method needs to be used alongside, and confirmed by, clinical knowledge. Future research should extend these findings to a wider range of clinical conditions for greater applicability in the day‐to‐day orthodontic practice. [ABSTRACT FROM AUTHOR]

Objective This study aimed to investigate the clinical characteristics of deciduous fused teeth and their inherited permanent-tooth performance type by using panoramic radiographs. Methods A total of 14 404 panoramic radiographs of 3- to 6-year-old children with deciduous dentition were collected from January 2023 to July 2024. The incidence of deciduous fused teeth was observed, and the abnormality of permanent teeth was recorded. SPSS 24.0 software was used for statistical analysis. Results The incidence of deciduous fused teeth was 3.06% (441/14 404). The order of dental position was as follows: mandibular deciduous incisors and cusp teeth fused (58.18%) > mandibular deciduous central and lateral incisors fused (30.91%) > maxillary deciduous central and lateral incisors fused (8.89%) > deciduous incisors and supernumerary teeth fused (2.02%). Deciduous fused teeth were found in 226 boys and 215 girls, with no significant difference between the sexes (P>0.05). We observed one pair (87.76%, 387/441) and two pairs (12.24%, 54/441) of fused teeth (54/441), respectively. A total of 287 pairs of fusion teeth on the right side more than 208 pairs on the left side, and the difference between them was statistically significant (P<0.01). More fusion teeth existed in mandibular deciduous teeth (443 pairs) than in maxillary ones (54 pairs), and the difference between them was statistically significant (P<0.01). More unilateral deciduous teeth (387 subjects) were found than bilateral ones (54 subjects), and the difference between them was statistically significant (P<0.01). Three types of deciduous fused teeth with inherited permanent teeth were observed as follows: 1) 49.49% (245/495) of inherited permanent teeth was absent, 2) 46.67% (231/495) of inherited permanent teeth was not absent, and 3) the number of fused permanent teeth accounted for 3.84% (19/495). Conclusion The incidence of deciduous fused teeth was 3.06%, mostly occurring in the lower anterior teeth region, with no gender difference. One pair of fused teeth is commonly observed, more often on the right than the left. These fusions occur more frequently in the mandible than the maxillary, and unilateral cases are more common than bilateral ones. Deciduous fused teeth had a certain impact on inherited permanent teeth. Pediatric dentists should pay attention to and closely observe whether any abnormality exists in the permanent dentition for early detection to prevent the harm caused by deciduous fused teeth. [ABSTRACT FROM AUTHOR]

Objective To study the clinical effect of the L-shape technique combined with concentrated growth factor on the horizontal bone defects of maxillary anterior teeth. Methods Twenty-five implants from 25 patients who underwent single maxillary anterior tooth implantation with simultaneous bone grafting were selected as the study subjects. Based on the bone grafting techniques, the patients were divided into a test group (L-shaped technique with guided bone regeneration combined with concentrated growth factor, 11 cases) and a control group (traditional guided bone regeneration combined with concentrated growth factor, 14 cases). The early discomfort and wound healing conditions in the two groups at two weeks after surgery were compared. The horizontal bone thickness, vertical bone thickness, and grayscale values in the augmentation area were measured immediately postsurgery and six months after surgery. Implant stability, hard tissue resorption within six months, and grayscale values were compared between the two groups. Results Differences in early discomfort, wound healing, implant stability, and grayscale values between the two groups were not statistically significant (P>0.05). Vertical bone thickness in the test group was significantly better than that in the control group at six months after surgery (P<0.05). The variation in horizontal bone thickness in the test group was significantly higher than that in the control group (P<0.05). Conclusion The application of the L-shape technique with concentrated growth factor for horizontal bone defects in the anterior maxillary area yielded satisfactory short-term results in terms of bone augmentation, early discomfort, wound healing, and implant stability at six months after surgery. [ABSTRACT FROM AUTHOR]

Background and Aims: The display of an individual's teeth varies in different facial expressions, which significantly affects the beauty of the lower face and overall appearance. The ideal display of incisors is influenced by lip morphology and is an essential aspect of treatment planning. This study aimed to evaluate the ideal display of incisors at rest in women with different lip forms, as assessed by dentists and laypeople. Materials and Methods: This was a cross-sectional study that was conducted in 2024 at Babol University of Medical Sciences. 46 dentists and 92 laypeople were selected and included in the study in an easy and accessible way. The distance between the uppermost area from the lower edge of the vermilion of the upper lip to the imaginary line between the two commissures was used to classify the lip shape, which was divided into three categories: straight (0-3 mm), medium (3-6 mm) and long (more than 6 mm). Smile images of three women in the age range of 15-30 years were collected and manipulated, resulting in six new images from each original image with varying degrees of incisor display using Photoshop (a total of 18 images). The designed images were randomly placed in a booklet and given to participants, who scored each image on a scale of zero to 100. The data were analyzed by SPSS software version 22 and using the Mann-Whitney test at a significance level of 0.05. Results: A total of 138 participants took part in the study, including 46 dentists (33.3%), comprising 17 males (37%) and 29 females (63%), and 92 laypeople (66.7%), including 46 males (50.0%) and 46 females (50.0%). Laypeople gave higher scores to images of straight and moderate lip forms than dentists. However, this difference was not statistically significant (P>0.05). In addition, dentists gave significantly higher scores to all images related to the long lip form than laypeople (P<0/05). In addition, among laypeople, men gave a higher score than women to images related to straight and moderate lip form, which was statistically significant (P<0.05). Conclusion: The findings of this study indicated that a 2.5 mm incisal display at rest was suitable for patients with a straight lip form. In general, it can be concluded that by changing the shape of the lip from straight to long, there is a preference for increasing the amount of incisal display in the resting state. [ABSTRACT FROM AUTHOR]

Objectives: This study aims to assess the awareness and acceptance of preventive and interceptive orthodontic treatment among Saudi perents. Methods: The study used a 29-question questionnaire, covering parents' demographic data, parents' awareness of malocclusion and habits, and parents' acceptance of treatment. It included visuals of different malocclusions, normal occlusion, and specific habits. Results: Parents mostly recognized single anterior tooth crossbite (95.78%) as a problem that need early intervention, followed by skeletal Class II (94.16%) and severe lower incisor crowding (93.51%). Regarding oral habits, parents were most aware of thumb sucking (91.03%), followed by tongue thrusting (84.22%). Ninety seven percent of participating parents expressed high acceptance of early orthodontic intervention, mostly to avoid more complicated treatment or surgery. However, a few parents refused early treatment, mainly because they preferred to wait until the eruption of all permanent teeth. Conclusions: The majority of parents demonstrated a high level of awareness and willingness to pursue early treatment. [ABSTRACT FROM AUTHOR]

This study aimed to evaluate a new modified fixed appliance for rehabilitation of premature loss of anterior teeth in preschool children versus a modified Nance appliance on maxillary arch growth with parental satisfaction. The study was conducted as a clinical trial and it was carried out at Pediatric Dentistry Department, Faculty of Dentistry, Tanta University. Forty preschool children from both genders aged from 3–5 years were included in the study. The selected children were divided into two groups; Group I: Twenty children received a modified fixed bridge. Group II: Twenty received a modified Nance appliance. Evaluation of both appliances on maxillary growth was carried out at baseline, 6 and 12 months. Finally, parental satisfaction was also recorded. It was revealed that, there was continuous maxillary growth in both groups at different follow up periods with no sexual dimorphism, and parental satisfaction was significantly higher in group I than group II. A modified fixed bridge was better than Nance appliance regarding parental satisfaction and it doesn't interfere with maxillary growth. [ABSTRACT FROM AUTHOR]

Background: The maintenance of the integrity of the anterior dentition plays a vital role in maintaining the beauty of the face. The repair schemes of anterior teeth loss mainly include implant denture, traditional fixed bridge, bonding bridge and removable partial denture. Among them, the bonding bridge is a minimally invasive fixed denture repair method that relies on bonding technology for retention, which has the advantages of simple operation, a small amount of grinding of the required abutment teeth, comfort, beauty, and no self-removal. Therefore, we reported a case of digital guide plate-assisted resin-based ceramic bonding bridge repair of anterior teeth loss. Case report: A 28-year-old woman was admitted to our hospital because left upper anterior teeth missing for more than 3 months. Minimally invasive tooth preparation assisted by digital guide plate+resin-based ceramic single-ended bonding bridge repair were performed. After treatment, the ideal clinical effect was achieved. Conclusion: Slightly tooth preparation with the assistance of a digital guide plate is used to guide the precise bonding of the prosthesis in repairing anterior teeth loss. [ABSTRACT FROM AUTHOR]

An 18-year-old Chinese woman presented with chief complaints of crowded teeth and mild mandibular prognathism. Clinical and imaging examinations revealed a concave profile, a protruded chin, increased lower anterior facial height mild, skeletal Class III and Angle's Class III malocclusion, with anterior crossbites, and crowded teeth. Extraction camouflaged therapy combined with miniscrews skeletal anchorage was employed to relieve crowding and retract the mandibular anterior teeth. The total active treatment time was 31 months. After treatment, functional occlusion and smile esthetics were significantly improved. [ABSTRACT FROM AUTHOR]

Background: Establishing accurate, reliable, and convenient methods for enamel segmentation and analysis is crucial for effectively planning endodontic, orthodontic, and restorative treatments, as well as exploring the evolutionary patterns of mammals. However, no mature, non-destructive method currently exists in clinical dentistry to quickly, accurately, and comprehensively assess the integrity and thickness of enamel chair-side. This study aims to develop a deep learning work, 2.5D Attention U-Net, trained on small sample datasets, for the automatical, efficient, and accurate segmentation of enamel across all teeth in clinical settings. Methods: We propose a fully automated computer-aided enamel segmentation model based on an instance segmentation network, 2.5D Attention U-Net. After data annotation and augmentation, the model is trained using manually annotated segmented enamel data, and its performance is evaluated using the Dice similarity coefficient metrics. A satisfactory image segmentation model is applied to generate a 3D enamel model for each tooth and to calculate the thickness value of individual enclosed 3D enamel meshes using a normal ray-tracing directional method. Results: The model achieves the Dice score on the enamel segmentation task of 96.6%. This study provides an intuitive visualization of irregular enamel morphology and a quantitative analysis of three-dimensional enamel thickness variations. The results indicate that enamel is thickest at the incisal edges of anterior teeth and the cusps of posterior teeth, thinning towards the roots. For posterior teeth, the enamel is thinnest at the central fossae area, with mandibular molars having thicker enamel in the central fossae compared to maxillary molars. The average enamel thickness of maxillary incisors, canines, and premolars is greater than that of mandibular incisors, while the opposite is true for molars. Although there are individual variations in enamel thickness, the average enamel thickness graduallly increases from the incisors to the molars among all teeth within the same quadrant. Conclusions: This study introduces an automatic, efficient, and accurate 2.5D Attention U-Net system to enhance precise and efficient chair-side diagnosis and treatment of enamel-related diseases in clinical settings, marking a significant advancement in automated diagnostics for enamel-related conditions. [ABSTRACT FROM AUTHOR]

Background: In dentistry, local anesthetic is frequently used to manage pain throughout several phases of dental treatments, including tooth extraction. The study aimed to compare the effectiveness of two techniques for controlling pain during mandibular exodontia (tooth extraction), specifically focusing on the pain experienced during injection and extraction of mandibular anterior and premolars teeth. The two techniques being compared are the intraligamentary injection technique (ILI) and the incisive nerve block technique (INB). Materials and methods: In this study, 100 mandibular anterior and premolars and teeth that were indicated for extraction were included. The effectiveness of the two local anaesthesia techniques, intraligamentary injection technique (ILI) and incisive nerve block (INB), were compared using Modified Dental Anxiety Scale for Dental Extraction Procedure (MDAS-DEP) and visual analogue scale (VAS) during the injection and extraction stages of the procedure. Results: A total of 100 participants (42 females, 58 males) with a mean age of 50.97 ± 11.59 years took part in the study. The mean VAS score in the INB group was 6.14 after injection and 3.86 after extraction, while in the ILI group, it was 5.46 and 2.90, respectively. There was a statistically significant difference between the two groups both after injection (p = 0.001) and extraction (p < 0.001), as well as within each group (Control: p < 0.001; Study: p < 0.001). For MDAS-DEP, the INB group had mean scores of 15.86 and 11.26 after injection and extraction, respectively, while the ILI group had scores of 15.68 and 10.94, showing a significant difference within each group after both injection (p < 0.001) and extraction (p = 0.001). However, no significant difference was found when comparing MDAS-DEP scores between the two groups from injection to extraction (p = 0.802). Conclusion: The intraligamentary injection technique (ILI) appears less painful during injection and provides profound pain relief during extraction. The results suggest that ILI can be used as a sole anaesthetic technique during extraction of lower anterior and premolar teeth. Trial registration: This trial was retrospectively registered on 27/01/2023 with the identifier ISRCTN83272316 in Isrctn.com. [ABSTRACT FROM AUTHOR]

Background: Anterior open bite is a challenging condition for pediatric dentists and orthodontists as it causes aesthetic, speech, feeding, and psychological problems; this emphasizes the need for early diagnosis and interception of this malocclusion. Aim: This study aimed to evaluate the effects of prefabricated metal-bonded tongue tamers and customized bonded spurs in the early treatment of anterior open bite. Materials and methods: A sample of seventy-five children aged 7–9 years were assigned into three groups in which anterior open bite was treated using tongue tamers (group-I), customized composite bonded spurs(group-II), and conventional fixed palatal cribs (group-III). Study model and cephalometric x-ray evaluations were done before and after a three-month follow-up. Data was gathered and statistically analyzed using ANOVA and Bonferroni tests. Results: Model overbite at central and lateral incisors was increased in all groups. The highest increase was found in group-I(3.16 ± 1.17, 2.81 ± 0.94)and group-III(3.08 ± 1.10,2.99 ± 1.00) though the difference was not statistically significant. Also, cephalometric overbite was non-significantly increased in all groups with a high increase in group-III(3.13 ± 1.10). Overjet decreased in all groups, with the greatest reduction observed in group-I(-2.58 ± 1.02 and -2.47 ± 0.80 in model and cephalometric respectively) and was significantly different from group-II using pairwise analysis. There was a decrease in SNA and ANB in all groups with more significant improvement in groups-I(-1.20 ± 0.88,-1.65 ± 0.74) and -III(-1.31 ± 0.92, -1.62 ± 0.75) than group-II(-0.63 ± 0.46, -0.90 ± 0.43). Moreover, FMA measurements decreased significantly in group-I (-2.6 ± 1.11). Regarding SNB measurement, there was a non-significant increase in all three groups with the highest increase in group-I(0.49 ± 0.48) followed by group-III(0.34 ± 0.63). The U1/FHP and L1/GoGn angles were non-significantly decreased in all tested groups with the highest decrease in group-I(-1.76 ± 1.00 and-2.54 ± 0.87 respectively). Conclusion: Early treatment of anterior open bite, along with tongue tamers' simplicity and aesthetics promoted the malocclusion correction and occlusal function restoration. Trial registration: ClinicalTrials.gov, NCT05792553, "Effects of Tongue Tamers as an Early Treatment of Anterior Open Bite", Retrospectively registered: 31/03/2023. [ABSTRACT FROM AUTHOR]

Objective: To study the biomechanical changes induced by differences in perioral force in patients with missing anterior maxillary teeth at rest via finite element analysis (FEA). Methods: Using conical beam CT (CBCT) images of a healthy person, models of the complete maxillary anterior dental region (Model A) and maxillary anterior dental region with a missing left maxillary central incisor (Model B) were constructed. The labial and palatine alveolar bone and tooth surface of the bilateral incisor and cusp regions were selected as the application sites, the resting perioral force was applied perpendicular to the tissue surface, and the changes in maxillary stress and displacement after the perioral force was simulated were analyzed. Results: Compared with Model A, the labial alveolar bone in the missing tooth area of Model B shows significant stress concentration under the action of perioral force. This adverse stress is distributed in an inverted V-shape, concentrated at the top of the labial alveolar ridge and gradually decreases toward the root. Conclusion: In the resting state, labial soft tissue exerts adverse stress on the alveolar ridge in areas missing maxillary anterior teeth. This stress may affect alveolar bone healing, causing a reduction in alveolar bone width. [ABSTRACT FROM AUTHOR]

Introduction: Tooth shade selection is a fundamental factor in the success of dental restorations, and visual impairment may adversely affect this process. The aim of this cross-sectional clinical study was to determine whether visual impairment influences shade selection using two methods: spectrophotometry and shade guides. Materials and Methods: The sample consisted of 2796 maxillary and mandibular teeth, and shade selection was measured subjectively with a shade guide (VITA Classic, VITA Zahnfabrik) and objectively with a spectrophotometer (VITA Easyshade® V, VITA Zahnfabrik, Bad Säckingen, Germany). In all cases, three measurements were taken on each tooth, with a waiting time of 15 min between samples. Shade selection was compared between observers with normal vision, myopia, astigmatism, and hyperopia. Results: The results show that myopic subjects perceived the lower central incisors (2.63, p < 0.05), upper lateral incisors (2.42, p < 0.05), lower lateral incisors (2.34, p < 0.05), and lower canines (2.64, p < 0.05) more clearly. Non-astigmatic subjects perceived the lower second premolar as lighter than astigmatic subjects (−2.01, p < 0.05). Conclusions: It can be concluded that myopes see teeth more clearly, but no differences have been found in astigmatism and hyperopes. [ABSTRACT FROM AUTHOR]

Background/Objectives: The literature suggests that the cranial base angle is considered one of the contributing factors to sagittal jaw malpositions when its relationship with the viscerocranium is examined. Our study aims to compare and evaluate the outcomes of fixed functional orthopedic treatment in patients with mandibular retrognathia across different cranial base groups. Methods: Participants were treated at Erciyes University with fixed functional appliances and categorized by CBA into low (<130°), medium (130°–134°), and high (>134°) groups. A total of 39 patients were included: 13 in the low CBA group (7 males, 6 females; mean age 14.62 ± 1.12 years), 13 in the medium CBA group (3 males, 9 females; mean age 14.38 ± 0.96 years), and 13 in the high CBA group (4 males, 9 females; mean age 14.08 ± 1.04 years). Results: In the low CBA group, Ar-Go-N (p = 0.005) and SNA (p = 0.023) angles significantly decreased, while the ANB angle and Wits appraisal significantly decreased across all groups (p < 0.05). The high CBA group showed increases in ANS-Me, N-Me, N-ANS, and N-Gn lengths (p < 0.05). The medium and high CBA groups had significant increases in S-Go and ANS-Gn lengths, while Co-Gn length increased significantly in the low and high CBA groups (p < 0.05). Incisor measurements (IMPA, L1-APog, L1/NB, L1-NB) increased in all groups, with overjet and overbite reduced (p < 0.05). U1/PP (p = 0.039), U1/SN (p = 0.043), U1-NA (p = 0.030), and U1/NA (p = 0.025) parameters increased in the low CBA group, with the Upper Lip–E distance decreasing significantly in the low and high CBA groups (p < 0.05). A comparison between groups showed significant differences in U1/PP, U1-NA, and U1/NA parameters, which increased in the low and medium CBA groups but decreased in the high CBA group. Conclusions: CBA influences treatment outcomes. The low CBA group experienced decreases in Ar-Go-N and SNA angles, while the high CBA group showed increases in certain vertical facial dimensions. Incisor parameters rose in the low and medium CBA groups but decreased in the high CBA group, suggesting limited CBA effects on treatment results. [ABSTRACT FROM AUTHOR]

Tooth discoloration that cannot be treated with more conservative procedures such as bleaching or microabrasion, requires restorative treatment to mask the unesthetic appearance. Ceramic veneers provide exceptional resistance to wear and abrasion, retain their glazed luster over a very long time, and are durable. This case report presents the rehabilitation of a patient with discolored composite restorations on maxillary anterior teeth with zirconia veneers fabricated using computer-aided-design/computer-aided-manufacturing technology. [ABSTRACT FROM AUTHOR]

This study aimed to estimate the number of distinct tooth colors using a large dataset of in-vivo CIELAB measurements. It further assessed the coverage error (CE) and coverage error percentage (CEP) of commonly used shade guides and determined the number of shades needed for an ideal guide, using the Euclidean distance (ΔEab) and thresholds for clinical perceptibility (PT) and acceptability (AT) as evaluation criteria. A total of 8153 untreated maxillary and mandibular anterior teeth were measured in vivo using calibrated dental photography. Cardinality was applied to determine the number of unique natural tooth colors. The CE and CEP were calculated for the Vita Classical and Vita 3D-Master shade guides, while the cardinality method was also used to estimate the number of shades required to adequately cover the estimated gamut of natural tooth colors. The cardinality analysis revealed 1173 unique natural tooth colors. The CE for the Vita Classical shade guide was 4.1 ΔEab, with a CEP of 75 % beyond AT, while the 3D-Master shade guide had a CE of 3.3 ΔEab and a CEP of 70 % beyond AT. Based on cardinality computation, 92 discrete shades are required to adequately cover the estimated gamut of natural tooth colors with a CE of 1.2 ΔEab and CEP of 0.3 % beyond AT. Cardinality computations estimated 1173 unique tooth colors while 92 discrete shades are estimated for full coverage. Such a number is impractical for physical shade guides, but new digital tools and 3D printing may offer future solutions. Both, the Vita Classical and 3D-Master shade guides do not fully represent the range of natural tooth colors. This study highlights the limitations of existing shade guides and underscores the potential for new developments. [ABSTRACT FROM AUTHOR]

To conduct a systematic review and network meta-analysis (NMA) to answer whether endocrown restorations have similar mechanical behavior than other traditional core-crown systems with or without intracanal posts for the rehabilitation of anterior endodontically treated teeth. The review followed the PRISMA Extension Statement for NMA. Studies were identified by a systematic search to select reports on endocrown restorations in anterior teeth. A search was performed in PubMed (MEDLINE), Scopus, Web of Science, Embase, SciELO, and LILACS databases. Articles evaluating mechanical performance through in vitro and finite element analysis (FEA) studies were selected and the risk of bias was assessed using the RoBDEMAT and ROBFEAD tools, respectively. The data were analyzed qualitatively and quantitatively through NMA using the MetaInsight tool. Eleven articles were included (eight in vitro and three with FEA design). Six in vitro studies were evaluated using NMA. Composite resin endocrowns showed greater load-to-fracture and lower occurrence of catastrophic failures than traditional restorations. Combining glass fiber post with composite restoration also showed good strength behavior. Regarding FEA studies, two out of three studies showed a more homogeneous distribution of stress for the endocrown group. Endocrowns performed similarly to or better than conventional restorative strategies, with composite resin being the most recommended material of choice. The rehabilitation of endodontically treated anterior teeth with extensive coronal destruction is typically challenging for the dentist, and there is still no consensus in the literature that provides conclusive answers for choosing the appropriate material and restorative strategy. Exploring new techniques and materials that make this procedure easier for the dentist and guarantee good results is paramount. [Display omitted] [ABSTRACT FROM AUTHOR]

The purpose of this paper is to report the case of an 8-year-old female with occlusal interferences involving the permanent maxillary right central incisor (PMRCI) due to a Type 1 dens evaginatus, also known as a talon cusp (TC), causing displacement of the affected tooth. Clinical concerns related to TCs include occlusal interferences and increased risk for dental injury, displacement of the affected tooth, caries, tongue irritation and esthetic concerns. The TC in this report was reduced periodically over two months. Following each reduction, 5% topical sodium fluoride varnish was applied as a desensitizing agent. Upon completion and removal of the TC, sealant (Ultra Seal XT R plus TM, Ultradent Products, Inc. USA) material was applied to the lingual surface of the affected tooth. The patient was evaluated five weeks after treatment completion, during which time, no clinical signs or symptoms related to the reduction were reported. [ABSTRACT FROM AUTHOR]

Objective: To evaluate the ideal anteroposterior position of incisors in lateral smiling profiles with different chin prominences and to relate these positions to nose and chin landmarks based on the perceptions of orthodontists and laypersons. Methods: A lateral smiling profile image of a female subject was adjusted to create five levels of chin prominence (-6, -3, 0, +3, +6 mm). For each level, the anteroposterior positions of the maxillary incisors were adjusted across five positions (-4, -2, 0, +2, +4 mm). Thirty-six orthodontists and 36 laypersons rated the attractiveness of each profile using a visual analog scale. The maxillary incisor position (U1) was measured relative to the external nose and chin landmarks (E-lines). Differences in perceptions between orthodontists and laypersons were analyzed. Results: For profiles with 6 and 3 mm chin retrusion, the most favored incisor positions were the 2 mm retrusion and unaltered positions, respectively. For the unaltered chin prominence, orthodontists preferred unaltered incisors, while laypersons favored 2 mm protrusion. Conversely, for 3 and 6 mm chin protrusion, both groups preferred 4 and 2 mm protrusion, respectively. The distance between U1 and the E-line is the most attractive images ranged from 8.5 to 11.5 mm. Based on the regression model, an optimal U1-E-line distance of 8.95 mm was recommended. Conclusions: The preferred incisor position is influenced by chin prominence, with the incisor position shifting in the same direction as the chin. The U1 E-line can be a useful clinical tool for determining the proper incisor positioning. Esthetic perceptions were generally consistent between orthodontists and laypersons. [ABSTRACT FROM AUTHOR]

Objective: Miniscrews are commonly utilized as temporary anchorage devices (TADs) in cases of maxillary protrusion and premolar extraction. This study aimed to investigate the effects and potential side effects of two conventional miniscrew configurations on the maxillary incisors. Methods: Eighty-two adult patients with maxillary dentoalveolar protrusion who had undergone bilateral first premolar extraction were retrospectively divided into three groups: non-TAD, two posterior miniscrews only (P-TADs), and two anterior and two posterior miniscrews combined (AP-TADs). Cone-beam computed tomography was used to evaluate the maxillary central incisors (U1). Results: The AP-TADs group had significantly greater U1 intrusion (1.99 ± 2.37 mm, n = 50) and less retroclination (1.70° ± 8.80°) compared to the P-TADs (-0.07 ± 1.65 mm and 9.45° ± 10.68°, n = 60) and non-TAD group (0.30 ± 1.61 mm and 1.91° ± 9.39°, n = 54). However, the AP-TADs group suffered from significantly greater apical root resorption (ARR) of U1 (2.69 ± 1.38 mm) than the P-TADs (1.63 ± 1.46 mm) and non-TAD group (0.89 ± 0.97 mm). Notably, the incidence of grade IV ARR was 16.6% in the AP-TADs group, significantly higher than the rates observed in the P-TADs (6.7%) and non-TAD (1.9%) groups. Multiple regression analysis revealed that after excluding tooth movement factors, the AP-TADs configuration resulted in an additional 0.5 mm of ARR compared with the P-TADs group. Conclusions: In cases of maxillary protrusion and premolar extraction, the use of combined anterior and posterior miniscrews enhances incisor intrusion and minimizes torque loss of the maxillary incisors. However, this approach results in more severe ARR, likely due to the increased apical movement and composite force exerted. [ABSTRACT FROM AUTHOR]