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The article focuses on comparing the accuracy of Invisalign in achieving predicted tooth movement of the maxillary central incisors and locating the center of rotation in labio-palatal direction, analyzing the impact of different wear protocols. Topics include assessing the discrepancy between predicted and achieved angular movements, exploring root movement control, and comparing wear protocols' efficacy in achieving predicted tooth movements and center of rotation.

This document discusses two cases of dental conditions known as molar-incisor hypomineralization (MIH) in children. In the first case, a 7-year-old boy had severe MIH in all four first permanent molars, leading to the extraction of these teeth. Over a 10-year follow-up period, radiographs showed that the second molars migrated mesially without vertical eruption. In the second case, a 9-year-old boy had severe crowding and impacted canines, as well as MIH in the lower left first permanent molar. After extractions and orthodontic treatment, the teeth were aligned and the patient achieved acceptable esthetics. The document emphasizes the importance of appropriate timing and collaboration between dentists and orthodontists in managing cases of MIH. [Extracted from the article]

This article presents a case report on the treatment of a labially impacted canine using orthodontic and surgical techniques. The authors describe the use of a closed-eruption or tunnel technique to expose the impacted tooth and guide its eruption into the center of the alveolus. The treatment involved the use of archwires, elastics, and various appliances to align the canine. After 30 months of treatment, the impacted canine was successfully brought into the arch, resulting in improved occlusion, alignment, and periodontal health. [Extracted from the article]

This article explores the interdisciplinary management of congenitally missing and malformed teeth. It emphasizes the importance of a team approach involving orthodontists and restorative clinicians to achieve optimal results. The article provides case illustrations to demonstrate different treatment options and considerations for each case, such as premolar extraction, dental implants, and resin-bonded bridges. It highlights the prevalence of tooth agenesis and dental anomalies in patients with congenitally missing teeth. The overall goal is to provide information and guidance for managing these dental conditions in a way that is aesthetically pleasing and functional for the patient. [Extracted from the article]

This document provides a comprehensive overview of the challenges and management of worn or broken-down dentition. It emphasizes the importance of understanding the underlying causes and treatment goals for each case, taking into account factors such as occlusion, tooth presence, and facial proportions. The document highlights the use of conservative restorative options, but acknowledges that more invasive approaches may be necessary in certain cases. It also discusses the role of orthodontics in managing complex restorative and esthetic challenges, as well as the collaboration between prosthodontists and orthodontists in treatment planning. The document showcases case studies that demonstrate the interdisciplinary approach to restorative and orthodontic treatment, and discusses the use of digital technologies in dentistry. Overall, the document emphasizes the importance of achieving natural-looking results while maintaining functionality in dental restorations. [Extracted from the article]

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Background. This in-vivo study evaluated the accuracy of full-arch digital impressions obtained through different intraoral scanning technologies regarding trueness and efficiency against the standard alginate impressions. Methods. Alginate impressions were taken from 50 subjects, and the resulting stone casts were scanned using the Trios 3Shape desktop scanner. In-vivo scans were conducted on each participant using three intraoral scanners: Medit, CEREC Primescan, and 3Shape Trios. The scanned files were superimposed onto two software platforms: the 3Shape Orthoanalyser and Geomagic software. This superimposition was performed against the reference model to calculate 3D and 2D deviations, enabling efficiency comparisons between digital and traditional workflows based on work time in minutes. Measurements and comparisons were made in three planes: transverse, sagittal, and vertical dimensions for all the models and stone casts. Statistical analysis employed SPSS 23, with the significance level set at P < 0.05. Results. Significant deviations were observed between the three intraoral scanners and the alginate impression, with molar and premolar areas showing greater imprecision across dental arches. Compared to the alginate technique, Medit i500 tended to reduce the transverse dimension in the areas mentioned above, while CEREC exhibited higher precision. Molar and premolar areas emerged as the regions with the greatest discrepancies, both in excess and deficiency, compared to the alginate impression. This difference in dimensions was, however, statistically insignificant overall. 3Shape Trios exhibited the shortest scan times, indicating higher efficiency. Among the intraoral scanners, Medit recorded the longest scanning duration. Conclusion. Accepting the null hypothesis, the scans obtained using all three scanners were comparable with statistically insignificant differences in the measurements. The three scanners differed in the total scan time taken, with the Medit scanner requiring the longest scan time and the 3Shape TRIOS 3 scanner demonstrating the shortest scan duration. [ABSTRACT FROM AUTHOR]

Objective: The aim of this systematic review was to elucidate the role of orthodontic retainers on the stability of compensatory orthodontic treatment in patients with unilateral cleft lip and palate. Methods: Five electronic databases (PubMed, Scopus, Web of Science, LILACS, and LIVIVO) and the grey literature (OpenGrey and Google Scholar) were investigated, according to the population, exposure, comparator, outcomes and Study design eligibility criterion. The risk of bias assessment was determined based on the Risk of Bias In Nonrandomized Studies of Exposure (ROBINS-E) and the level of evidence with the GRADE tool. Results: Three studies were included: two presented moderate risk of bias and one high. A moderate level of evidence revealed a mean value of 0.6 mm of intercanine relapse distance, and great variability between the data, regardless of the use or type of retention or rehabilitation. Relapse in the posterior region showed clinical significance, from −1 to −1.7 mm, especially in individuals who did not use retention, except in patients with symmetrical arches with Hawley retainer, where this value varies from −0.2 ± 0.63 mm. Conclusions: Orthodontic retainers do not seem essential to prevent relapse at anterior maxillary dimensions after compensatory orthodontic treatment in patients with unilateral cleft lip and palate. Relapse in the posterior region can achieve greater clinical significance, which highlights the need for prolonged use of Hawley retainers and periodic evaluation of the stability of treatment results. Prospective studies with a longer follow-up can improve the certainty of the evidence. [ABSTRACT FROM AUTHOR]

Objective: To examine skeletal morphology and dental arch relationships at 8 years of age following early 2-stage palatoplasty, which consists of soft palate plasty at 1 year of age and hard palate closure at 1.5 years of age, and to compare the results with those of conventional pushback palatoplasty. Design: Retrospective. Setting: Single institutional study. Patients: Eighty-six patients with nonsyndromic complete unilateral cleft lip and palate (UCLP) were selected. Intervention: The subjects were divided into 2 groups according to the palatoplasty protocols, as follows: 45 patients, who underwent early 2-stage palatoplasty (ETS group), and 41 patients, who underwent 1-stage pushback palatoplasty (PB group). Main Outcome Measures: Skeletal morphology was assessed using lateral cephalometric analysis, and dental arch relationships were examined using the GOSLON yardstick. Results: Cephalometric analysis revealed that the anterior-posterior length of the maxilla, measured by PTM-A and PTM-ANS, both projected to the nasal floor (NF) plane, was longer in the ETS group than in the PB group (PTM-A/NF, p =.04; PTM-ANS/NF, p =.03, unpaired t -test), although no significant difference was observed in SNA (p =.09, unpaired t -test). Upper posterior facial height was shorter in the ETS group than in the PB group (p =.02, unpaired t). Assessments with the GOSLON yardstick showed that the ETS group presented better dental arch relationships than the PB group (p = 0.04, Mann–Whitney's U -test). Conclusions: The present results suggested that the ETS protocol reduced the negative effects of palatal surgery on facial development and dental arch relationships in patients with complete UCLP at 8 years of age. [ABSTRACT FROM AUTHOR]

Background: Single-component adhesives do not require the application of a primer on the enamel surface that has been etched and has been reported to have acceptable shear bond strengths on in vitro evaluation. Aim: This split-mouth study aimed to examine and assess the rates of bracket bond failure of hydroxyethyl methacrylate (HEMA)-based (Aqualine LC) and bisphenol A-glycidyl methacrylate (BisGMA)-based (Orthofix SPA) single-component adhesives used to bond orthodontic brackets over 6 months. Materials and Methods: This in vivo study involved the participation of 50 adult subjects, with 1080 metallic brackets directly bonded to the labial/facial surface in a split-mouth design. After 6 months of treatment, 49 patients with 490 brackets bonded using a HEMA-based adhesive and 490 brackets bonded using a BisGMA-based adhesive were evaluated for bracket bond failures. Descriptive statistics and chi-square tests were done to compare the results. Results: The overall bracket bond failure rate (BFR) with single-component adhesives was 6.02%. Bracket BFRs of HEMA-based and BisGMA-based adhesives were 4.16% and 7.8%, respectively, and the difference was statistically significant (P < 0.05). Significant differences in BFRs between maxillary teeth (4.28%) and mandibular teeth (7.75%) were noted (P < 0.05). No significant differences in bond failures between either side or region were noted. Conclusion: Bond failures were more in brackets bonded with BisGMA-based adhesive (Orthofix SPA) compared with HEMA-based adhesive (Aqualine LC). Bond failures were less in the maxillary arch. [ABSTRACT FROM AUTHOR]

The gradual movement of a tooth away from the occlusal plane is called infraocclusion or reinclusion. Reincluded teeth are most often deciduous molars, and permanent teeth are less frequently affected. Depending on the level of the infraocclusion, the severity of the disorder is classified as mild, moderate, or severe. The etiology of the phenomenon is not fully known. Tooth submerging can lead to serious complications, such as abnormal position of adjacent teeth, displacement of the bud of the permanent successor, shortening of the dental arch, or developmental disturbances of alveolar process. Early diagnosis of the tooth infraocclusion and regular monitoring of its progression help to avoid serious permanent sequelae. The treatment of reinclusion often involves only observation. However, in some cases, the therapeutic procedure requires interdisciplinary treatment by specialists from various fields of dentistry. This study presents current methods of diagnosis and treatment of patients with submerged teeth. [ABSTRACT FROM AUTHOR]

This article presents the design of customized resin scan bodies with different forms and their use to facilitate intraoral scanning of a maxillary full arch implant case with five implants. The aim is to limit the distance between the scan bodies and to create definite landmarks to facilitate the scanning process in full arch implant cases. [ABSTRACT FROM AUTHOR]

Objective: To investigate the most common retention practices, factors influencing the retention protocol, and the differences among orthodontists regarding retention practices. Methods: An online validated questionnaire was anonymously sent to 3,000 orthodontic residents and clinicians. The survey consisted of 19 questions regarding the participants' demographics, prescribed retention appliances, factors affecting retention appliance choices, and adjunctive retention procedures. Descriptive statistics, Chi2 and Kendall's Tau-b tests were applied. Results: Five hundred fifty-five orthodontic residents and clinicians, 53.3% males and 46.7% females, completed the survey, indicating a response rate of 18.5%. Although participants' demographics, type of treatment and pre-treatment malocclusion influence the choice of retention protocols, thermoplastic retainers (TR) were the most popular retention regime for the maxillary arch for both adults (47.4%) and adolescents (42.3%). Bonded retainers (BR) were the favored option for the mandibular arch (44.9% of adults and 40.7% of adolescents). The degree of arch expansion (64.1%) and the degree of interdigitation (50.1%) after treatment were the most influential factors for the choice of the preferred type of retainers by the respondents. 68.6% of the participants thought professional retention guidelines would be useful. Conclusion: Thermoplastic retainers were the most common retention appliances for adults and adolescents in the maxilla. At the same time, BR was the most favored retainer in the mandibular arch, with clinical experience, practice setting, and malocclusion- and treatment-related factors influencing the type of the chosen appliance. The demographic differences and the uneven participation in the survey need to be considered while interpreting the findings of this study. [ABSTRACT FROM AUTHOR]

Purpose: The objective of this study was to determine the minimum number of teeth in the anterior dental arch that would yield accurate results for individual identification in forensic contexts. Materials and Methods: The study involved the analysis of 28 sets of 3-dimensional (3D) point cloud data, focused on the labial surface of the anterior teeth. These datasets were superimposed within each group in both genuine and imposter pairs. Group A incorporated data from the right to the left central incisor, group B from the right to the left lateral incisor, and group C from the right to the left canine. A comprehensive analysis was conducted, including the evaluation of root mean square error (RMSE) values and the distances resulting from the superimposition of dental arch segments. All analyses were conducted using CloudCompare version 2.12.4 (Telecom ParisTech and R&D, Kyiv, Ukraine). Results: The distances between genuine pairs in groups A, B, and C displayed an average range of 0.153 to 0.184 mm. In contrast, distances for imposter pairs ranged from 0.338 to 0.522 mm. RMSE values for genuine pairs showed an average range of 0.166 to 0.177, whereas those for imposter pairs ranged from 0.424 to 0.638. A statistically significant difference was observed between the distances of genuine and imposter pairs (P<0.05). Conclusion: The exceptional performance observed for the labial surfaces of anterior teeth underscores their potential as a dependable criterion for accurate 3D dental identification. This was achieved by assessing a minimum of 4 teeth. [ABSTRACT FROM AUTHOR]

Background: This study aims to analyze the longitudinal variation of occlusal force distribution prior to and after fixed restoration for molar full-crowns with T-SCAN III which provide reference for occlusal adjustment and long-term maintenance. Methods: We enrolled a total of 20 patients who received conventional restorative treatment for molars. The occlusion examination was conducted in 3 stages (before placement, immediately after placement, and 3 months after placement) using T-SCAN III (Tekscan South Boston, MA, USA, 10.0) to examine and measure the occlusal contact areas of the full dentition. Results: The results indicated that the occlusal force distribution in the molar region of the patients changed before and after the fixed restoration, but the percentages of occlusal force in the dental arch of the molar did not differ significantly before and after the restoration (P > 0.05). Three months after the fixed restoration, the percentage of occlusal force in the restored dental arches of lateral teeth increased significantly (P < 0.05). Conclusion: The results of this study indicated that the occlusal forces of the patients changed with tooth movement and adaptation, which is mainly reflected in the increasing occlusal force. Quantitative occlusal force analysis using T-SCAN III occlusal analyzer can provide more objective and accurate data to effectively guide clinical occlusion adjustments. [ABSTRACT FROM AUTHOR]

Scissor bite does not correct spontaneously. It gradually worsens by overeruption, negatively affecting masticatory function. It is intended with this manuscript to evaluate the different treatment strategies to correct this malocclusion in adult patients, exploring treatment with clear aligners, bite ramps, and MS (miniscrews), especially in this case of a patient with unilateral right scissor bite, with high dental compensation in the three planes of space, asymmetrical sagittal dental position, overeruption on the scissor bite condition, and a high mandibular arch constriction and maxillary expansion. A comprehensive literature research was performed from 2002 until March 2023. PubMed and BVS databases were used, with the following keywords: "scissor bite OR brodie bite" AND "malocclusion" AND "treatment OR correction OR therapeutics". Since correcting skeletal asymmetries after the growth completion is challenging, adult patient cases often involve a combined orthodontic-surgical approach. In the present clinical case, the severe limitations to decompensating tooth positions for a surgical treatment, with the necessity to perform lower asymmetric extraction and a must longer orthodontic treatment, were the major reasons to avoid the surgical approach, after the scissor bite correction. In spite of this, the efficiency of the clear aligners and auxiliaries like bite ramps, MS, and elastics in successfully correcting a complex scissor bite in an adult patient was demonstrated, with significant esthetic and functional commitment, demonstrated by the case reliability PAR (peer assessment rating) index. [ABSTRACT FROM AUTHOR]

Introduction: The prevalence of adults with partially dental arches is expected to be more than imagined and patients requiring replacement of missing teeth are slowly increasing in number too. Removable partial dentures are known to provide for substantial replacement for the missing teeth with also added advantages when compared to fixed or implant prosthesis, mainly in elderly patients. Denture base material performance and durability are greatly influenced by wettability and water contact angle. In the case of dentures; adequate moisture distribution is necessary to ensure excellent wettability which has an influence on comfort and oral health. The purpose of conducting this study was to find out whether the advancements made using PEEK (Polyether ether ketone) would prove to be more beneficial than the current upgrades in the current material spectrum. Materials and methods: This study was performed under in vitro conditions. All the fabrication and processing was done only by one operator. The materials used were divided into three groups each comprising 20 samples. Group A was modified polymethylmethacrylate (Bredent Polyan), Group B was polyoxymethylene acetal resin (Biodentaplast) and Group C was PEEK. An Ossila Goniometer was used to measure the contact angle. The three types of liquids used for the testing included distilled water, natural saliva and mouth wetting solution (Wet Mouth Liquid, ICPA India). Human saliva was collected from an individual with no medical conditions and normal salivary secretion. Results: The data was analyzed using One-way ANOVA test and a pairwise comparison using the Post Hoc Tukey's Honest Significant Difference. Table 1 consists of the mean water contact angles of the denture base materials and mean contact angles of various denture base materials. In saliva, mouth wetting solution and distilled water, the highest mean and least mean contact angle was seen in Polyan and Biodentaplast respectively. A signicant difference was seen between PEEK and Polyan and Biodentaplast and Polyan on further comparison. Conclusion: From the resources and the materials at our disposal, it could be concluded that Polyan, Biodentaplast and PEEK and could be used as viable options in cast partial denture framework. [ABSTRACT FROM AUTHOR]

Background: Vertical maxillary excess (VME) is one of the most common reasons for seeking orthodontic treatment. Total intrusion with aligners is a promising alternative to surgery in some cases. Considering the elastic deformation of aligners, this study aimed to evaluate the possible desirable and undesirable teeth displacements during full maxillary arch intrusion using clear aligners and temporary anchorage devices (TADs). Methods: The maxillary arch and clear aligners were modeled in SolidWorks. Four aligner brands including Leon, Duran, Duran Plus, and Essix Plus were selected based on their material properties. Anterior and posterior intrusion forces of 80 and 300 g were applied from attachments between the canines and first premolars and between the first and second molars, respectively. Vertical and anteroposterior tooth displacements were determined. Results: The greatest intrusion was recorded at the buccal of the second molar, followed by the first molar. The lowest value was measured at the palatal of the molars with all aligners except Duran, which indicated minimal intrusion in the central incisor. All teeth were mesially displaced at the incisal/occlusal except incisors that moved distally. All apices showed distal movement. Conclusions: Total intrusion using clear aligners may be accompanied by other tooth movements, including buccal tipping and mesial-in rotation of the molars, retrusion of incisors, and mesial movement of other teeth. [ABSTRACT FROM AUTHOR]

Objective: To analyse the anterior teeth effects of clear aligners on five different patterns of mandibular molar movement and to define the most effective configuration to be implemented with clear aligners through finite element analysis. Methods: A three-dimensional mandibular model with a deep overbite in the mandible was constructed using cone beam computerized tomography (CBCT) data. The model included the mandibular dentition, mandibular periodontal ligaments, attachments, and aligners. Five models were created: (1) configuration A: second molar distalization (0.25 mm); (2) configuration B: second molar distalization (0.25 mm), first molar extrusion (0.15 mm); (3) configuration C: second molar distalization (0.25 mmm), first and second premolar extrusion(0.15 mm); (4) configuration D: second molar distalization (0.25 mm), first molar and first/second premolar extrusion(0.15 mm); and (5) configuration E: second molar distalization (0.25 mm), first molar and first/second premolar extrusion (0.15 mm), first molar and first/second premolar expansion (0.15 mm). Results: In all configurations, the anterior teeth exhibited labial tipping and the mandibular central incisor of configuration E showed the highest labial tipping. Configuration E demonstrated a relatively minor impact on mandibular molars distalization compared with configuration A. Configuration A showed the highest distal displacement value, and configuration E produced the lowest displacement value. Configuration E caused the highest periodontal ligament (PDL) pressure of the central and lateral incisors. The differences in the canines between configurations C and D,were not significant, and the stress distribution differed among the five groups. Conclusions: All patterns utilizing clear aligners facilitated mandibular molar distalization. Extruding the premolars and second molar distalization at the same time had little impact on second molar distalization; When expansion and extrusion were simultaneously performed during the distalization of mandibular molars, our prime consideration was the alveolar bone on the labial side of the anterior teeth to prevent the occurrence of gingival recession, dehiscence, and fenestration. Due to the lack of consideration for periodontal tissues in this study, clinical protocols should be designed based on the periodontal status of the mandibular anterior teeth. [ABSTRACT FROM AUTHOR]

(1) Background: This study aims to investigate, within a controlled laboratory environment, the magnitude of the transversal load and the force decay over time produced by clear aligners in comparison to a Rapid Palatal Expander (RPE). (2) Methods: Resin models of a dental maxillary arch, additively manufactured from an intraoral scan, were inserted in a testing machine with uniaxial load cells to measure the force trend over time expressed by RPE and clear aligners. The mechanical load was recorded during a certain timeframe for both appliances. (3) Results: The force expressed by the RPE ranged from 30 to 50 N for each activation, decreasing with a nonlinear pattern over time. The force expressed by the clear aligner ranged from 3 to 5 N, decreasing with a linear pattern over time. In contrast, the force generated by the clear aligner fell within the range of 3 to 5 N, showing a linear reduction in force magnitude over the observed period of time. (4) Conclusions: The RPE exerted a force magnitude approximately ten times greater than that generated by clear aligners. Nevertheless, it is essential to acknowledge that the oral environment can significantly influence these results. These limitations underscore the need for caution when applying these findings to clinical settings. [ABSTRACT FROM AUTHOR]

Background: Various clinical studies performed in adults have shown the relationship between craniofacial morphology and masticatory muscle function. However, the growth of the masticatory muscle has not received such attention, when compared with the volume of studies on the skeletal growth of face. With this background and considering the widespread use of ultrasonography (USG), the following study was undertaken to provide some insights into the relationship between muscle and bone and facial morphology. Methods: This was a prospective, observational study conducted over a period of three years from 2012 to 2015 to assess the correlation between the thickness of the masseter muscle in Angle's normal occlusion and the various malocclusions of the dental arch as well as the facial form. Patients with a full complement set of teeth, normal tooth morphology, Angle's normal occlusion, Angle's class I-III malocclusion, those with a history of third molar extraction, and impaction were included in the study. Those with a history of any prior orthodontic treatment, restorations, or any missing teeth (except the third molar) were exempted from the study. The greater thickness of masseter muscle in relaxed and clenched state was recorded on USG. Facial morphology was determined with the aid of facial photographs. Results: The study was conducted on 140 patients. The class I normal occlusion group had the thickest masseter muscle, while the class III malocclusion group had the thinnest masseter muscle. Facial parameters showed highly significant gender-wise differences in class I normal occlusion, class I malocclusion, and class II division II malocclusion. There was a significant negative co-relation between the thickness of masseter muscle and facial forms in all the categories of Angle's classification as indicated by a negative regression coefficient B (P < 0.05). Conclusion: The masseter muscle thickness correlated directly with male gender and normal occlusion, and inversely with the degree of malocclusion and facial form. [ABSTRACT FROM AUTHOR]

Mini-screws, also known as temporary anchorage devices (TADs), offer enhanced control and versatility in orthodontic treatment by providing stable anchorage points. This clinical study aims to evaluate the effectiveness of mini-screw-supported molar intrusion in orthodontic practice. For this clinical study, a cohort of 40 orthodontic patients with various malocclusions requiring molar intrusion as part of their treatment plan was recruited. The age range of the participants spanned from 14 to 35 years, representing a diverse patient population. The intervention involved the implementation of mini-screw-supported molar intrusion on one side of the maxillary arch in each patient. To achieve this, temporary mini-screws were strategically placed, and a combination of orthodontic forces and mini-screw anchorage was employed to intrude the molars. The primary outcome measure for this study was the amount of molar intrusion achieved, which was quantified in millimeters from the initial evaluation to the final visit. Additionally, the duration of treatment required to achieve the desired molar intrusion was recorded in months. The results of this clinical study demonstrated that mini-screw-supported molar intrusion was an effective and safe orthodontic technique. On average, a significant mean molar intrusion amount of 4.8 mm (standard deviation [SD] ± 0.6) was achieved with the mini-screw-supported approach. Furthermore, the treatment duration required to attain the desired molar intrusion was relatively short, with a mean of 6.2 months (SD ± 1.1). In conclusion, this clinical study provides evidence that mini-screw-supported molar intrusion is an effective and safe approach in orthodontic practice. It offers orthodontists the advantage of enhanced control and predictability in molar intrusion procedures. [ABSTRACT FROM AUTHOR]

This article explores the orthodontic treatment of a horizontally impacted mandibular second molar. The case report focuses on a patient who had an impacted molar causing dental complications. Instead of extracting the tooth, a cantilever uprighting spring made of stainless steel wire was used to upright the molar without surgery or additional anchorage. The treatment involved the extraction of other teeth, followed by the insertion and activation of the cantilever spring. After nine months, the molar was successfully exposed and brought into occlusion, resulting in a stable occlusion and improved facial profile. The article also discusses other methods for aligning the tooth after it has been uprighted and exposed. [Extracted from the article]

The article explores the use of a boneborne vertical distractor to extrude an ankylosed maxillary first molar. Ankylosis of the molar can lead to problems such as lack of movement and infraocclusion. The case study presented in the article demonstrates the successful use of a vertical periodontal ligament distractor to extrude the ankylosed molar. The article also discusses other treatment options for ankylosed teeth, including orthodontic space closure and surgical procedures. The boneborne distractor is highlighted as a method that avoids negative effects on neighboring teeth. The authors emphasize the advantages of vertical periodontal ligament distraction, such as its minimally invasive nature, ability to maintain proper oral hygiene, and aesthetic appeal. They also note the need for further long-term studies to assess the stability of vertically distracted teeth. [Extracted from the article]

This article discusses a custom-made spring appliance that can correct excessive root torque in cases with buccally erupted ectopic canines. It provides case studies and demonstrates the successful repositioning of ectopic canines using the appliance. The treatment involves the use of torquing auxiliary springs and sectional wires to correct the torque and alignment of the canines. The authors emphasize the importance of well-planned biomechanics in achieving successful tooth movements and avoiding complications. The article provides detailed descriptions of the treatment procedures and includes radiographs and images to illustrate the cases. [Extracted from the article]

This study aimed to assess the relationship between apical fenestration—a defect in the alveolar bone involving the root apex—and tooth position in all tooth groups, excluding the third molars, utilizing cone-beam computed tomography (CBCT) images. A total of 800 CBCT scans (400 maxillary and 400 mandibular) from patients undergoing various treatments were examined by a single professional (radiologist and endodontist). Statistical analyses, including the chi-square test or Fisher's exact test, were conducted using R software 2.7.3 (R Foundation, Vienna, Austria). Results indicated a significant association (p ≤ 0.05) between apical fenestration and tooth position. In the upper teeth, apical fenestrations were notably present in the mesio-buccal (17.17%) and disto-buccal (11.07%) roots of the first molars. Conversely, apical fenestrations in the lower teeth were relatively less frequent. The study revealed a negative correlation between apical fenestration and mesial inclination, rotation, and extrusion in the upper teeth. However, a positive correlation was observed between apical fenestration and lingual inclination in the upper teeth. In conclusion, this study illuminates the distribution of apical fenestration and its correlation with tooth positions, offering insights into factors influencing this defect in dental anatomy. The findings enhance our understanding of nuanced relationships between tooth position and apical fenestration in the upper and lower dental arches. [ABSTRACT FROM AUTHOR]

Background: The visible maxillary arch width (VAW) is an important aesthetic‐determining feature. To date, there is no well‐established methodology to determine the aesthetically optimal VAW in customized treatment planning. Methods: In this study, the common traits of the dentofacial configuration were investigated in most attractive Asian and Caucasian female smiles. The smiling photo of a subject was digitally modified based on combined variations of VAW, smile width (SW), transverse facial dimensions (TFD), and vertical facial dimensions. These modified photos were assessed for aesthetics. The aesthetically essential parameters were identified, and their mathematic correlations and reference ranges were determined for different vertical facial patterns. Using the obtained results, a mathematic guidance was constructed for customized smile designing. The applicability of this guidance was tested in Asian females. Results: The most attractive Asian and Caucasian female smiles have intraracial and interracial commonalities in the VAW‐to‐TFD ratios. The interparopia width (IPD) predominated over facial widths in determining well‐matched VAW and SW. For optimal smile aesthetics, the VAW and SW were correlated as simulated by the formula 1.92 IPD ≤ VAW + 2.3 SW ≤ 2.17 IPD, plus the VAW‐to‐IPD ratio within 0.54 to 0.62 and the SW‐to‐IPD ratio within 0.61 to 0.71, ranges tailored to vertical facial patterns. This constitutes a mathematic guidance for customized planning of the aesthetically optimal VAW. This guidance was preliminarily validated to be applicable to Asian females. Conclusions: The VAW‐to‐TFD ratios were essential for Caucasian and Asian female smile aesthetics. The mathematic guidance could serve as a reference for customized smile designs for Asian females. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this cross‐sectional clinical study was to determine and compare alveolar ridge mucosa thickness at crestal, buccal, and lingual locations of the maxillary and mandibular arches in completely edentulous patients using a dedicated, ultrasonic gingival scanner. Materials and Methods: Thirty‐eight completely edentulous subjects were included in the study. In each subject, soft tissue thickness was measured at 28 sites of the edentulous ridge by a single calibrated examiner. Intra‐observer reliability was calculated with Intraclass Correlation Coefficients by measuring 10 subjects twice, after 1 week. Measurements (mm) were taken at the buccal, lingual, and crestal aspects of the ridge with a dedicated ultrasonic scanner. Repeated measures ANOVA and paired t‐tests were used to compare the mean buccal, lingual, and crestal soft tissue thicknesses at each site. The Generalized Estimating Equations model was used to study the effects of age, sex, and race. Confidence level was set to 95%. Results: Mean tissue thickness ranged from 0.96 to 1.98 mm with a mean of 1.63 ± 0.25 mm. Intraclass Correlation Coefficients were > 0.97. No significant differences between buccal, crestal, and lingual sites were noted for the mandibular arch as well as at 4 sites on the maxillary arch (maxillary right second molar, maxillary right canine, maxillary left first premolar, maxillary left second molar). However, significant differences in soft tissue thickness were noted for all remaining maxillary sites. Race was found to be positively correlated with tissue thickness, with Black individuals showing a significantly greater thickness than White individuals at 4 sites (maxillary right first molar, maxillary left canine, mandibular right second premolar, mandibular right first molar). Age was found to be positively correlated with tissue thickness at 4 sites (maxillary left central incisor, maxillary left first molar, maxillary left second molar, mandibular left second premolar) and negatively correlated at 2 sites (mandibular right canine, mandibular right second molar). Female sex was positively (maxillary left second premolar, maxillary left second molar) and negatively (mandibular right canine) correlated, respectively, with tissue thickness at 3 sites. When data for anterior and posterior sites were respectively pooled, tissue thickness was significantly less at anterior sextant lingual and crestal sites, while no difference was seen for buccal sites. Conclusion: Statistically significant differences for alveolar ridge mucosa thickness were found at several sites in the maxilla and between anterior and posterior sextants for lingual and crestal sites in the maxillary and mandibular arches. Tissue thickness differences were also noted for race with Black individuals showing greater tissue thickness at some sites. Age and sex did not show a clear effect on tissue thickness. Recorded differences in tissue thickness were however small and appear of uncertain clinical significance. [ABSTRACT FROM AUTHOR]

This paper presents a method for the digital transfer of the upper maxillary arch position using a facebow, a transfer table, and a reference block with a CAD application without requiring physical casts mounted with articulating gypsum. This technique facilitates the prosthetic digital workflow when the impression is made via intraoral scanning, to obtain the placement of the maxillary arch in the anatomical reference planes and in relation to the axes of rotation of the mandibular movements [ABSTRACT FROM AUTHOR]

Purpose: To compare the accuracy of digitizing conventional impressions to intraoral surface scans for all‐on‐four treatment in the maxillary arch. Materials and methods: An edentulous maxillary arch model with four implants placed in an all‐on‐four design was fabricated. Intraoral surface scans (n = 10) were obtained using an intraoral scanner after scan body insertion. For conventional polyvinylsiloxane impressions of the model, implant copings were inserted into the implant fixation for implant level, opened tray impressions (n = 10). The model and conventional impressions were digitized to obtain digital files. A reference file was created using a laboratory‐scanned conventional standard tessellation language (STL) file with analog to scan the body using exocad software. STL datasets from the two digital and conventional impression groups were superimposed with reference files to assess the 3D deviations. Two‐way ANOVA and paired‐samples t‐test was performed to assess the difference in trueness and examine the effects of impression technique and implant angulation on the deviation amount. Results: No significant differences were found between the conventional impression and intraoral surface scan groups F(1, 76) = 2.705, p = 0.104. No significant differences were found between conventional straight and digital straight implants and between conventional and digital tilted implants F(1, 76) =.041, p = 0.841. No significant differences were found between conventional straight and conventional tilted implants p = 0.07 and between digital straight and digital tilted implants p = 0.08. Conclusion: Digital scans were more accurate than conventional impressions. The digital straight implants were more accurate than the conventional straight implants, and the digital tilted implants were more accurate than the conventional tilted implants, with higher accuracy for digital straight implants. [ABSTRACT FROM AUTHOR]

ABSTRACT Introduction: Extraction vs. non-extraction is a crucial decision in orthodontic therapy. Objective: The aim of the present study was to investigate the changes in the dental arch width and buccal corridor after orthodontic treatment using extraction and non-extraction therapy with Damon self-ligating system. Material and Methods: This retrospective study consisted of 35 patients (20 female and 15 male patients with median age of 12.5 years), treated by extracting 4 or 2 premolars, and 37 patients (16 female and 21 male patients with the median age of 12.8 years), treated without premolar extraction. Both groups were treated with Damon self-ligating system. Plaster models before (T0) and after (T1) treatment were measured, and the arch width values were determined at the level of the first molars, second premolars, canines and palatal rugae. Buccal corridor width was measured using the extraoral images at T0 and T1. Paired t-test was used for the analysis of the normally distributed data, and Wilcoxon Mann-Whitney U test was used for the data with non-normal distribution. Values of p

Abstract This study mapped definitions of shortened dental configurations and health outcomes employed in association studies. A scoping review was conducted using the PubMed/Medline, Scopus, Web of Science, SciELO and Cochrane databases. Two trained researchers selected studies and extracted data. Studies that investigated the association between shortened dental configurations (exposure) and person-centered outcomes (general and oral health) related to health behavior (dietary patterns). Clinical outcomes were classified according to the International Classification of Functioning, Disability and Health and the International Classification of Diseases of the World Health Organization (WHO). Shortened dental configurations were defined as at least 20/21 teeth or the position of the teeth, including esthetics, dental occlusion and periodontal status (Eichner Index, Shortened Dental Arches, Functional Dentition Classification System, Posterior Occluding Pairs, Functional Tooth Units). The initial search resulted in 12,525 records in English, Portuguese and Spanish, 432 of which addressed the association of interest. General health (n = 203) and oral health (n = 201) were addressed in a similar number of studies. Most outcomes were related to general health (n = 184), the most frequent of which were endocrine, nutritional or metabolic diseases (n = 57) and mental functions (n = 26). Person-centered measures were addressed in 153 studies, most of which were about oral health and oral health-related quality of life (n = 62). Oral health outcomes were predominantly related to intake functions (n = 44) and diseases or disorders of the orofacial complex (n = 24). Dietary patterns (n = 43) and mortality (n = 38) were also studied. The cross-sectional design (n = 257) and non-probabilistic sampling (n = 218) were more frequent. The shortened dental configurations defined by the WHO were the most frequent in the studies (n = 206). The effects of shortened dental configurations have been investigated mainly in relation to endocrine, nutritional or metabolic diseases and measures of oral health-related quality of life. The findings point to a diversity of health outcomes assessed and substantial methodological variability.

Introduction: Interest in self‑ligating brackets is generally smoother and more comfortable. Objectives: To compare rate of retraction and rotational control of maxillary canines with self‑ligating MBT brackets on one side and conventional MBT brackets on the other side of the maxillary arch. Materials and Methods: Ten subjects with a mean age range of 18 to 25 years were selected. For each patient in the maxillary arch, bonding was performed with 0.022‑inch slot conventional MBT brackets on one side and 0.022‑inch slot self‑ligating MBT brackets on the other side. Stainless steel 0.009‑inch ligatures are used for conventional ligation. Retraction of canines was performed with 0.019 × 0.025‑inch stainless steel wires using NiTi closed coil springs with eyelets of 12 mm and 9 mm. The force of retraction was measured using a dynamometer. Dental casts were made at each time interval to record the canine retraction rate (in mm) and rotation (in degrees). Results: The mean difference in the retraction rate was 0.045 mm/month between self‑ligating and conventional brackets, respectively (P > 0.05). The mean difference of total rotation of canines with self‑ligating and conventional brackets was 1.5°, which gives evidence that there was less rotation of canines with self‑ligating brackets. Conclusion: There was no statistically significant difference in canine retraction rates between conventional and self‑ligating brackets. Secure ligation with the self‑ligating brackets showed better rotational control than the conventional brackets. [ABSTRACT FROM AUTHOR]

The present report explores the use of self-ligating brackets in treating Class I malocclusion with mild crowding and a constricted maxillary arch. Self-ligating brackets, designed as an alternative to expansion appliances, prove effective in expanding the maxillary arch by allowing larger archwires. The benefits include reduced friction, potentially faster and more comfortable tooth movement, and easier dental hygiene. While commonly associated with non extraction orthodontics, self-ligating brackets are adaptable to cases requiring tooth extraction for severe crowding. This assessment guides a personalised treatment plan, which may involve extraction, with careful placement of self-ligating brackets on remaining teeth. Hereby, the authors present a case report of 15-yearold female patient showchasing a unique technique for dealing with such cases, in which the advantages of self-ligating brackets are utilised to alleviate crowding with much simpler movement while also enhancing confidence. [ABSTRACT FROM AUTHOR]

The article focuses on a case of full-arch implant restoration that shows the effectiveness of incorporating a digital workflow in a dental practice. It suggests tools that clinicians may use for greater precision, predictability and patient satisfaction, including photogrammetry with cone beam computed tomography, digital photography and three-dimensional printing. It describes the benefits of using digital dentistry and the Nobel Biocare N1 system.

The article describes a case of correction of Class I malocclusion with severe crowding, misaligned teeth and crossbites of mandibular canines in a 27-year old male patient. ClearCorrect aligners were used by the clinician due to their ability to effectively meet the retention requirements of the case. The Unlimited case type was chosen for comprehensive treatment and long-term retention and to minimize unexpected expenses. The total treatment plan involved two phases.

This case report highlights the clinical management of a patient who presented with a long-standing pyogenic granuloma, dating back to childhood, causing a noticeable gap between the lateral incisor and canine in the maxillary arch. Following the successful excision of the granuloma, the patient expressed a desire to close the resulting space. A tailored treatment plan was devised and implemented in the Department of Prosthodontics at K.D. Dental College and Hospital, Mathura, to address the patient's aesthetic and functional concerns. [ABSTRACT FROM AUTHOR]

Restoring chewing function with various types of prostheses in case of partial loss of teeth remains an important task in orthopedic dentistry. The presence of defects in the dental arch leads to a violation of the integrity of the dentition and the appearance of morphofunctional changes in the dentoalveolar system, occurring first near the defect and then spreading to the entire dentition. This leads to vertical movement and inclination of teeth that limit the defect, devoid of antagonists, as well as overload of the remaining teeth, disruption of occlusion, and changes in the mandibular joint[1] [ABSTRACT FROM AUTHOR]

This article discusses a scientific study of a mummified child from Zagreb Cathedral in Croatia. The study aimed to gain a deeper understanding of the child's life and human physiology through medical and scientific assessment of the remains. The remains were imaged using various techniques, including digital radiographs and CT scans, and isotope analysis was conducted. The findings revealed that the child was between three and five years old at the time of death and that the mummification process likely occurred in the tenth century CE. The study raises questions about why the child was mummified using an old Egyptian technique despite the practice being discontinued in Egypt by the seventh century CE. Further molecular analysis is hoped to provide more insights into these questions. [Extracted from the article]

Mandibular canines, also known as the "cornerstone" of the dental arch, are important factors for dental arch stability, masticatory function, and maintaining natural facial expressions and aesthetics. Due to their eruption pattern and sequence, canines are prone to impactions with a 20 times higher frequency for maxillary canines than mandibular canines. Bilateral impactions of permanent mandibular canines are rare occurrences with a low incidence of 0.12%. Migration of teeth is a frequently documented ectopia. However, pre-eruptive migration across the midline of the arch is an unusual occurrence known as transmigration. Hereby the authors present a 29-year-old female patient who reported pain and swelling of the anterior mandible. On examination, it was revealed to be associated with bilaterally impacted permanent mandibular canines associated with transmigration. The case was managed by surgical extraction of both impacted teeth leading to resolution of the pain and swelling. [ABSTRACT FROM AUTHOR]

Purpose: To determine the effect of 0.7- and 2.4-mm transmucosal abutment height titanium bases on the crestal bone stability and peri-implant soft tissue condition of bone-level implants with platform switching in patients with vertically thick soft tissues. Materials and Methods: Sixty bone-level platform-switched implants were placed in the molar and premolar regions of both arches in 60 patients. All epicrestally inserted nonsubmerged implants had a 4.1-mm diameter and, after osteointegration, were randomly allocated into two groups: (1) the short group, with a titanium base of 0.7-mm transmucosal abutment height, and (2) the high group with a 2.4-mm height. Monolithic zirconia restorations were fabricated for all implants. Parallel intraoral radiographs were obtained after the delivery of restorations (T1) and after 1 year (T2). Crestal bone levels and peri-implant soft tissue conditions were calculated for each implant. The significance level was set at α = .05. Results: After 1 year, 55 patients were evaluated, with a mean bone loss of 0.6 ± 0.51 mm (median: 0.71, range: 0 to 2.09 mm) in the short group (23 patients) and 0.45 ± 0.59 mm (median: 0.65, range: 0 to 2.12 mm) in the high group (22 patients), showing no significant difference between groups (P = .168). A significant increase in marginal bone height was noted between the T1 and T2 time points in the short and high (P = .029 and .001, respectively) groups. The peri-implant soft tissue health parameters did not show statistically significant differences. Conclusion: Crestal bone stability after 1 year of follow-up around epicrestally placed platform-switched implants is not influenced by transmucosal abutment height, if the vertical soft tissue thickness is ≥ 3 mm. [ABSTRACT FROM AUTHOR]

various dental material substrates. Materials and Methods: A maxillary dentate typodont model with 11 different dental material substrates was prepared and scanned using three intraoral scanners (Trios 3, 3Shape; CS 3600, Carestream; and Emerald S, Planmeca). The model was also scanned with a laboratory scanner (7series, Dental Wings) for reference. Files were exported in standard tessellation language (STL) format and inserted into a metrology 3D mesh software (CloudCompare). Results: In terms of the influence of different substrates on intraoral scanner trueness, a significant effect on the performance of Trios 3 and Emerald S was found. Pairwise comparisons revealed significant differences among scanners concerning accuracy when scanning more translucent and reflective materials. In terms of complete-arch trueness and precision, pairwise comparisons revealed that the Trios 3 had significantly higher trueness and precision compared to both the CS 3600 and Emerald S, but the complete-arch trueness and precision of the CS 3600 and Emerald S did not differ significantly. Conclusions: Dental material substrates influenced the accuracy of all three tested scanners. The full-metal crown exhibited significantly lower trueness compared to other substrates across all three scanners. For the high-translucency substrate group, the Trios 3 exhibited significantly higher trueness compared to the CS 3600. Polished and unpolished Class II amalgam restorations of similar dimensions did not exhibit significant differences in trueness regardless of intraoral scanner. In terms of complete-arch accuracy, the Trios 3 had significantly higher trueness and precision compared to both the CS 3600 and Emerald S. All three scanners exhibited a mean complete-arch accuracy below 100 μm. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the influence of using different fabrication techniques, including intraoral scans, CBCT scans of patients’ existing dentures, or denture duplicates, on the accuracy of radiographic scan templates. The influence of selecting different segmentation threshold values during reconstruction of CBCT data was also evaluated. Materials and Methods: A reference model was obtained by scanning five pairs of maxillary and mandibular acrylic complete dentures using a desktop laboratory laser scanner (DWOS 7Series, Dental Wings). Test scans were obtained from intraoral scans of dentures, CBCT scans of dentures and denture duplicates reconstructed at different grayscale segmentation thresholds, and a laboratory scan of denture duplicates. The resultant STL scan files were imported to an open source and cloud storage software (Medit Link) for the accuracy measurements by calculating root mean square estimate (RMSE) between reference and test scans. Collected data were then analyzed. Qualitative analysis was also performed using 3D color maps. Results: The lowest RMSE (352.7) was found with intraoral denture scans. The highest RMSE (1,336.3) was found with the CBCT scans of the denture duplicates at segmentation threshold of –700 grayscale level. Qualitative analysis revealed that the intraoral denture scans exhibited the most homogenous deviation pattern relative to reference lab scans. Conclusion: Within the limitations of this study, the intraoral scans of the patients’ existing dentures resulted in the fabrication of the most accurate radiographic scan templates. The improved accuracy of scan templates fabricated using the intraoral scanners can eliminate the possible laboratory errors associated with the conventional technical procedures as well as reduce the inaccuracies resulting from the image processing and segmentation of CBCT data. [ABSTRACT FROM AUTHOR]

Purpose: Investigate the effects of three different complete-arch digital implant scanning techniques used with a combined healing abutment–scan body (CHA-SB) system on the accuracy (trueness and precision) and scan time. Materials and Methods: A poly(methyl methacrylate) master model simulating an edentulous maxilla was fabricated with four parallelly inserted dental implants. A CHA-SB system was attached to each implant. The model surface was scanned using a structured blue light industrial extraoral scanner to achieve a reference model standard tessellation language file (MRM-STL). Three different scanning techniques—(1) conventional technique with unmodified master model, (2) scan body splinting technique using orthodontic elastic ligatures and plastic splint materials, and (3) land-marking technique using pyramid-shaped glass-ceramic markers—were performed. Fourteen consecutive digital scans were made by using an intraoral scanner (IOS) for each technique, converted to an STL file, and superimposed on the MRM-STL. Trueness and precision were calculated for each technique. The scan time was also recorded. The data were analyzed with one-way analysis of variance (ANOVA) and Tukey honest significant difference (HSD) tests (α = .05). Results: Effects of different scanning techniques on the trueness (distance and angular deviations; P < .001) and scan time (P = .002) were statistically significant. For precision, different scanning techniques had only a significant effect on the distance deviation (P < .001). Conclusion: Regarding trueness and precision, none of the scanning techniques was superior to others. The scan body splinting technique led to significantly less scan time. [ABSTRACT FROM AUTHOR]

Purpose: To describe a digitally designed device for improving esthetic and occlusal planning for full-arch implant-supported rehabilitations.Materials and Methods: A step-by-step clinical and technical protocol is described to obtain an esthetic rim. Alternatives in terms of design and case requirements and the clinical use of the device are also described.Results/conclusion: An integral approach based on esthetic and functional needs is mandatory in full-arch restorations. The proposed device can improve teamwork and communication, minimizing possible errors. Future proposals are needed to achieve a fully digital protocol in the fabrication of these rehabilitations. [ABSTRACT FROM AUTHOR]

This pilot study aimed to assess the diagnostic accuracy of CBCT in identifying peri-implantitis-like bone defects in cadavers. Three cadaver dental arches treated with the Thiel embalming method were used. Three different types of peri-implant bone defects (buccal dehiscence, two- to three-wall defects, and circumferential defects) were prepared on 15 implants. Defect depths and lengths were identified clinically using a periodontal probe, radiologically by means of CBCT images, and histologically with a micrometer using an optic microscope. Peri-implant bone defect morphology evaluated using CBCT images matched the clinical defect configuration (100% accuracy). CBCT assessment demonstrated lower values in defect depth and defect length when compared with the clinical evaluation. A statistically significant difference in defect depth (0.35 ± 0.45 mm; P = .037) was recorded between the clinical and CBCT data. Regarding defect length, a statistically significant mean difference of 0.81 ± 0.83 mm (P = .003) was noted between the clinical and CBCT data. Similarly, a mean difference of 1.09 ± 1.52 mm was recorded between the defect length assessed histologically and the CBCT data (P = .031). No statistically significant differences were observed between the other evaluated variables. CBCT is a reliable tool for peri-implantitis diagnosis and treatment planning, though the underestimation of defect severity may affect the prognosis and clinical decision-making. Clinicians need to be flexible in establishing prognoses and treatment based on CBCT assessment. [ABSTRACT FROM AUTHOR]

Purpose: The main objective of this study was to assess the influence of bone remodeling on late marginal bone loss in immediately loaded, implant-supported, complete-arch restorations and, secondarily, to determine its relationship to peri-implant disease occurrence using a multilevel analysis. Materials and Methods: A retrospective cohort study of patients treated consecutively in a private clinic with immediately loaded full-arch restorations with at least 12 months of follow-up was conducted. Bone remodeling and marginal bone loss were determined through measurements made on panoramic radiographs by two calibrated examiners. Peri-implant health status was diagnosed in a visit for peri-implant maintenance. Descriptive, bivariate, and multilevel analyses were performed with Stata/IC 15.1 software (StataCorp). Results: A total of 30 patients (11 men and 19 women, mean age: 63.3 ± 10.4 years), with a mean follow-up of 37.7 ± 19.6 months were included. Forty arches (20 maxillary and 20 mandibular) received 207 implants. Bone remodeling had an inversely proportional effect on marginal bone loss (P =.005) but was not related to peri-implantitis (P =.103; hazard rate [HR] = 2.1). Conclusion: Taking into account the limitations of this study, bone remodeling around immediately loaded dental implants supporting complete-arch restorations does not appear to increase marginal bone loss or peri-implantitis. [ABSTRACT FROM AUTHOR]

BACKGROUND: In the treatment of edentulous maxillary implants supported fixed repair, the selection of upper scaffold structure materials and the design of different distal implant implantation methods have a close influence on the long-term stability of the whole mouth implant repair. OBJECTIVE: To comprehensively explore the influence of three different materials of upper scaffold and two implant fixation designs on the biomechanics of the fixed maxillary implant repair based on the three-dimensional finite element method. METHODS: Based on the conical beam CT data of a healthy adult with normal jaws, the Mimics software was used to separate the maxillary and maxillary dentin three-dimensional solid models, and the Geomagic Studio software was used to construct the three-dimensional finite element model of denture with denture implant and fixed maxillary arch combined with specific model parameters. According to the different designs of distal implants in the maxillary posterior region, two scheme models were established. Scheme 1 (Design 1) was designed in accordance with the “All-on-4” design used in clinical practice. Two implants were vertically implanted in the bilateral incisor region of the maxilla, and the other two implants were implanted in the bilateral second premolar region at a 30° angle. In scheme 2 (Design 2), two implants were vertically implanted in the lateral incisor region of the maxilla, and two short implants were vertically implanted in the posterior region of the maxilla in the bilateral second premolar region. Three materials (titanium, zirconia and polyether ether ketone) were used to assign values to the upper scaffold structure in the two designs, and six different models were obtained. The biomechanical effects of the implant, surrounding bone tissue and the upper scaffold structure were compared and analyzed in the oblique loading direction. RESULTS AND CONCLUSION: (1) The maximum stress peaks of all models were distributed in the neck region around the posterior implant and the cortical bone under the two edentulous implant fixed restoration schemes, regardless of the material of the upper scaffold. (2) Compared with the alternative design of Design 2, which adopted vertical implantation of short implants, Design 1 showed a more ideal stress distribution on the maxilla. (3) The scaffold model constructed by polyether ether ketone material transferred higher stress to the implant and surrounding bone tissue close to the loading zone of the upper jaw bone, followed by titanium and zirconia. As for the support itself, the peak stress of the upper scaffold of polyether ether ketone was significantly lower than that of the zirconia and titanium scaffolds. Zirconia scaffolds were used among the three upper scaffolds to disperse the stress distribution of implant and bone tissue. (4) The results suggest that both designs can be applied to clinical practice. However, from the perspective of biomechanics, the stress distribution of the implant, surrounding bone tissue and upper scaffold in Design 1 is more rational, which is more conducive to the long-term prognosis of fixed implant repair in patients with edentulous jaws. The upper scaffold material has a certain influence on the stress distribution of the implant-bone interface. [ABSTRACT FROM AUTHOR]

Background. For orthodontic treatment to be effective, bracket placement must be precise to make the finishing stage easier, leading to an ideal occlusion with minimal intervention. This study aimed to evaluate the accuracy of manual and digital bracket positioning techniques utilizing computer-aided design and computer-aided manufacturing (CAD/CAM) jigs, 3D-printed indirect bonding trays (IBT), and double-layer vacuum-formed thermoplastic IBT. Methods.This study was done by scanning the dental arch of 30 orthodontic patients. The virtual setup and bracket positioning were performed with the Insignia™ system for ten patients, and 3D Maestro® software was used for the virtual setup of the remaining 20 patients. At the same time, the bracket positioning of 10 patients was done digitally by the 3D Maestro® software and the remaining 10 patients manually through the Ray Set® device. IBT were fabricated by CAD/CAM system, 3D printer, and vacuum-formed thermoplastic machine. A virtual bracket position was compared to the actual bracket position using the best-fit method of 3D digital superimposition in Geomagic® Control X™ (CX) software to determine how accurate it was in terms of linear and angular accuracy. Statistical analyses using SPSS 26.0 including Bland–Altman plots were used to assess the intra-examiner reproducibility. Shapiro–Wilk test was used to measure normality distribution. Wilcoxon matched-pairs signed rank test was used to analyze the differences between bracket positions within each group. Results. Although there were obvious positional discrepancies between several readings, they were still within clinically acceptable ranges. Conclusions. All types of IBT would translate the planned position of the bracket from the digital and manual techniques to the teeth of patients with accepted precision in both linear and angular measurements; in addition, the error rate is about the same for all types of IBT. This trial is registered with NCT05549089. [ABSTRACT FROM AUTHOR]