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Background/aim: To investigate the feasibility of establishing a mandibular osteosarcoma model in Sprague-Dawley (SD) rats using tissue block transplantation, providing a foundational model for osteosarcoma research., Materials and Methods: Fourteen male SD rats, 3 weeks old and SPF grade, were randomly divided into a control group (n=4) and a mandibular osteosarcoma group (n=10). Using tissue block transplantation, UMR106 cell-induced tumor tissues were transplanted subcutaneously into the left mandibular marrow cavity of the SD rats. Observations included behavioral changes, weight variations, tumor growth, and tumor formation rate. Bone changes were monitored via micro-CT scanning, and histological analysis was conducted using HE staining., Results: Two weeks post-transplantation, the mandibular osteosarcoma group exhibited significant left facial swelling, malocclusion, eating difficulties, and weight loss compared to the control group. The tumor formation rate was 80% (8/10). Micro-CT scans indicated significant bone destruction in the osteosarcoma group. HE staining revealed high cellular atypia and pathological mitoses in both subcutaneous and mandibular osteosarcoma cells, with no notable abnormalities in lung tissues., Conclusion: Tissue block transplantation is a viable method to establish a mandibular osteosarcoma model in SD rats. This method is simple, with a high tumor formation rate, providing an ideal animal model for mandibular osteosarcoma research., (Copyright © 2024, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.)

Given the high prevalence of skeletal and mandibular diseases in the Patagonian Huemul, comprehensive anatomical studies are essential to understand the impact of nutritional deficiencies and support conservation efforts. The aim of this study is to provide a detailed anatomical characterisation of three exhumed mandibles of Patagonian huemul (Hippocamelus bisulcus) through three-dimensional reconstructions obtained from computed tomography data and semi-automatic segmentation, documenting their distinctive features. The findings revealed distinctive features in the mandible, consistent with the browsing habits of herbivores, such as a robust coronoid process, a wide and deep pterygoid fossa, a significantly lower mandibular condyle compared to other deer species and a unique configuration of the mandibular canal with a curved caudal portion and a straight rostral portion. These anatomical adaptations are likely related to the species' feeding habits and behaviour. The study also addressed the challenges of researching an endangered species, given that access to biological material is restricted by strict regulations in Chile and Argentina. These restrictions limited the available sample size and hindered the acquisition of additional specimens, which could affect the generalisation of the results. Despite these limitations, the research provides valuable anatomical insights that are fundamental for the biology, clinical practice and management of specimens. In conclusion, the mandibles of both juvenile and adult Patagonian huemul demonstrate distinctive features characteristic of browsing herbivores. The findings can serve as a basis for future comparative studies on mandibular anatomy and function in this endangered deer species as well as in other herbivorous deer., (© 2024 Wiley‐VCH GmbH. Published by John Wiley & Sons Ltd.)

Abstract: The presence of specific craniofacial deviations may be evidence of abnormal early brain development in bipolar disorder (BD). This study aimed to compare mandibular morphology in patients with BD versus nonpsychiatric controls using panoramic radiography. A total of 215 recorded images, 70 patients with BD and 145 controls, were evaluated. Seven mandibular parameters of the ramus height (RH), condylar height (CH), gonial angle (GA), antegonial angle (AGA), antegonial notch depth (AND), ramal notch depth (RND), and bigonial width (BGW) were measured in a blinded manner. Group analysis was conducted separately for males and females. The univariate comparisons showed increased values in RH, CH, AND, RND, and BGW and decreased values in GA in males with BD compared with male controls. In addition, females with BD had higher RH, CH, RND, and BGW values in comparison to female controls. The differences were statistically significant. Data from multivariate analyses revealed that increases in RH and BGW values in both sexes were significant predictive variables that distinguished patients with BD from controls. Moreover, deeper AND was the most prominent predictor that distinguished male patients with BD from male controls. The identification of subtle changes in mandibular measurements is consistent with the notion of impaired neurodevelopment in BD., (Copyright © 2024 Wolters Kluwer Health, Inc. All rights reserved.)

Objectives: This study aimed to assess the influence of the location and distribution of short-span scans, serving as intermediate registration data, on the trueness of digitally transferring the maxillomandibular relationship in full-mouth rehabilitation., Methods: Maxillary and mandibular complete-arch preparation casts mounted on an articulator were scanned, with and without interim restorations, using an intraoral scanner. Four types of short-span scans-right anterior, left anterior, right posterior, and left posterior-were captured from maxillary and mandibular casts. Each scan comprised two prepared teeth and two crowned teeth arranged alternately. These short-span scans served as intermediate data and were cross-registered with complete-arch interim restorations and preparation casts to transfer the maxillomandibular relationship. Based on the number (1 or 2), location (anterior or posterior), and distribution (unilateral or bilateral) of short-span scans, they were categorized into six groups. Trueness was assessed by evaluating the mandibular 3-dimensional (3D), spatial distance, angle, and linear distance deviations between the test and reference scans., Results: Significant differences in the trueness of digital cross-mounting were observed among the six groups (P < .05). The group registering the bilateral posterior areas exhibited the smallest 3D, spatial distance, angle, and linear distance deviations, whereas the group registering one anterior area showed the largest deviations., Conclusion: The number, location, and distribution of the registered short-span scans significantly affected the trueness of transferring the maxillomandibular relationship. A posterior short-span scan had higher trueness than an anterior scan. The symmetrical distribution of the two registered larger short-span scans over the cross-arch enhanced the registration trueness., Clinical Significance: Digital cross-mounting in full-mouth rehabilitation using short-span scans enhances transfer accuracy, improves patient comfort, and increases chairside efficiency., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier Ltd.)

Objectives: To investigate whether the scanning time, trueness and number of photos are influenced when augmented reality (AR) heads-up display (HUD) is utilized during the intraoral scan of fully dentate mandibular arches., Methods: A total of 10 patients (6 females and 4 males) were included. The mandibular arch of each patient was scanned twice using an intraoral scanner (Trios4 Pod IOS: 3Shape): one with and one without AR-HUD (ML2; Magic Leap). Further, alginate impression was taken, and the cast was digitized to acquire the reference model for trueness comparison (T310, Medit). The scan time and number of photos were recorded. Trueness was evaluated qualitatively and quantitatively using colored heat maps and RMSE values respectively. t-test was used to evaluate the difference in scan time, trueness, and number of photos between the two groups (α = .05)., Results: AR-assisted IOS resulted in significantly faster scan time (44 s) compared to the time consumed following conventional scan method without AR-HUD (63 s) (P = <0.001). The number of photos was also significantly less with AR-assisted IOS (836) compared to IOS using conventional technique without AR-HUD (1209) P = <0.001. No statistical difference was detected in RMSE between the test groups., Conclusions: Integration of AR technology with IOS process represents a promising potential to acquire digital impressions with reduced scan acquisition time and reduced images count while simultaneously maintaining the trueness of the acquired scans., Clinical Significance: Augmented Reality presents an emerging potential in Prosthodontics to acquire digital impressions with decreased number of images and acquisition time., Competing Interests: Declaration of competing interest The authors declare no conflict of interest., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Objectives: To compare mandibular incisor compensation relative to Menton (Me) deviation between skeletal Class III patients with roll- and yaw-dominant mandibular asymmetries., Materials and Methods: Sixty skeletal Class III patients (21.62 ± 2.69 years) with facial asymmetry were divided into roll- or yaw-dominant asymmetry groups. Mandibular skeletal and incisor measurements were carried out using cone-beam computed tomography data, and values were compared between the two asymmetry groups or between moderate and severe asymmetry subgroups using independent t-test or Mann-Whitney U-test. The relationship between skeletal and dental measurements was assessed using Pearson correlation coefficient., Results: Relative to the mandibular midsagittal plane, the yaw-dominant group presented significantly greater mandibular dental midline deviation in distance (LI-mid deviation, 2.15 mm) and angulation (4.20°) toward the nondeviated side than the roll-dominant group (P < .001). The ratio of amount of LI-mid deviation to Me deviation was significantly greater in the yaw-dominant group (26.44%) than in the roll-dominant group (1.76%; P < .001). In the yaw-dominant group, the LI-mid deviation was significantly greater in the severe asymmetry subgroup than in the moderate asymmetry subgroup, and the amount of mandibular incisor compensation was positively correlated with Me deviation and mandibular yaw., Conclusions: Mandibular incisor compensation differed significantly between the roll- and yaw-dominant asymmetry groups. The yaw-dominant group demonstrated significant mandibular dental midline deviation, and dental compensation of the anterior teeth was positively correlated with Me deviation and mandibular yaw., (© 2024 by The EH Angle Education and Research Foundation, Inc.)

Objectives: To compare the mandibular posterior space available before treatment and the distance of molar distalization achieved after mandibular dentition distalization with microimplants., Materials and Methods: A total of 66 Class I or III adult patients (mean age = 24.46 ± 4.89 years) who underwent molar distalization using microimplants were retrospectively included. The posterior space available distal to the second molar before treatment and the distance of distalization achieved after treatment were measured using axial cone-beam computed tomography images (0, 2, 4, and 6 mm apical to the second molar root furcation). Changes in lingual cortical thickness and molar root length after treatment were examined. Paired t-test or Wilcoxon signed-rank test was performed to compare measurements before and after treatment. Spearman correlation analysis was performed to assess the relationship between thinning of the cortical plate and root resorption., Results: Achieved distalization distance was significantly greater than pretreatment posterior space available by 0.8 mm at all root levels (P < .001). The difference was greater toward the root apex level and greater in the Class III group than the Class I group. Lingual cortical thickness was significantly decreased after treatment along with resorption of the second molar distal root (P < .001). In addition, a positive correlation was found between thinning of the cortical plate and distal root resorption of the molar (P < .001)., Conclusions: Achieved distalization distance of the mandibular molar using microimplants was greater than the pretreatment posterior space available. Thinning of the lingual cortex and root resorption were observed after distalization., (© 2024 by The EH Angle Education and Research Foundation, Inc.)

Pursuing a proficient age estimation methodology introducing novel radiographic methods remains an ongoing and demanding aspect of forensic and medicolegal research. In 2017, Roberts GJ et al. (J Forensic Sci 62(2):351-4, 2017) described a new radiographic method, i.e., root canal width (RCW) patterns to assign a subject to above 18-year-age threshold. Since then, few researchers have investigated the validity of this radiographic method in other populations. The present study aimed to test the usefulness of these RCW patterns in predicting 18 years in a sample of South Indian juveniles and sub-adults aged between 16 and 23. Descriptive analysis revealed that pattern-A was initially observed at a minimum age of 16.08 and 16.22 years in males and females. Pattern-B at 16.31 years in males and 16.22 years in females, while pattern-C was initially recorded at 18.73 years in males and 19.01 years in females, respectively. In summary, if an individual, regardless of sex, exhibits a fully-formed (apex closed) mandibular first, second, and third molars and concurrently displays RCW-C, there is a strong likelihood that the person has exceeded the legally relevant age of 18 years. However, due to higher rate of technically unacceptable errors (adults wrongly identified as individuals below 18 years), reliance on this method alone should be restricted, and it is advisable to combine it with other methods., (© 2024. The Author(s).)

The aim of this study was to investigate the stability of the proximal mandibular reference structures that have been proposed in the literature for superimposition. Forty proximal mandibular segments of 20 patients who underwent bilateral sagittal split osteotomy (BSSO) for advancement were reconstructed from a pair of pre- and postoperative (2 years) cone beam computed tomography scans, and spatially divided into the mandibular condyle, the coronoid process, and 20 mandibular ramus regions. To assess the stability of the anatomical regions, the volumetric and surface discrepancy between the superimposed pre- and postoperative regions were calculated. One-sample t-tests were applied to analyse the statistical stability of the individual regions. Two statistically stable (P < 0.05) structures in the proximal segment of the mandible following BSSO were identified: (1) the posterior part of the mandibular ramus above the gonial angle and below the condylar neck, and (2) the sub-coronoid area below the coronoid process/mandibular notch. Using these stable structures for superimposition resulted in an assessment discrepancy in the condylar displacement of up to 1.1 mm and in the volumetric change of up to 2.8%. Hence, it is suggested that these two identified stable structures are used as reference areas when assessing condylar displacement and change using superimposition., Competing Interests: Competing interests None. Competing Interests No competing interests., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Purpose: Orthodontic treatment involving premolar extractions might improve the angulation of lower third molars, which are the teeth most often impacted. This study analyzes the impact of first/second lower premolar extraction during orthodontic therapy on the angulation of mandibular third molars., Methods: A total of 120 patients treated non-extraction (n = 40), with extraction of first (n = 40), or second lower premolars (n = 40) were included. The mesiodistal angulation of lower third molars relative to the adjacent tooth and their developmental stage were evaluated from posttreatment orthopantomograms. Between-group differences were statistically evaluated at a significance level of 0.05., Results: The orthopantomograms of 120 patients (51% female) with a median age of 15.2 years at the time of debonding were evaluated after a mean treatment duration time of 2.9 years. No difference (P > 0.05) was seen between the average angulation of the lower third molars of the right (mean = 24.4°, standard deviation [SD] 13.6°) and the left side (mean = 23.6°, SD 14.1°). No differences in the angulation of the lower third molar were found between the non-extraction and extraction groups for the right (P = 0.44) or the left side (P = 0.22). Likewise, no differences were found when comparing the first and second premolars for the right (P = 0.26) or the left side (P = 0.10). Premolar extraction was associated with an advanced root development stage of the right third molar (odds ratio 7.1; 95% confidence interval 1.1-48.1; P = 0.04), with no differences between extraction of the first or second premolar (P = 0.10)., Conclusion: Orthodontic treatment involving premolars extractions might be associated with a small acceleration in root development, but not with the angulation, of lower third molars., (© 2023. The Author(s).)

Age estimation in forensic odontology is mainly based on the development of permanent teeth. To register the developmental status of an examined tooth, staging techniques were developed. However, due to inappropriate calibration, uncertainties during stage allocation, and lack of experience, non-uniformity in stage allocation exists between expert observers. As a consequence, related age estimation results are inconsistent. An automated staging technique applicable to all tooth types can overcome this drawback.This study aimed to establish an integrated automated technique to stage the development of all mandibular tooth types and to compare their staging performances.Calibrated observers staged FDI teeth 31, 33, 34, 37 and 38 according to a ten-stage modified Demirjian staging technique. According to a standardised bounding box around each examined tooth, the retrospectively collected panoramic radiographs were cropped using Photoshop CC 2021® software (Adobe®, version 23.0). A gold standard set of 1639 radiographs were selected (n 31  = 259, n 33  = 282, n 34  = 308, n 37  = 390, n 38  = 400) and input into a convolutional neural network (CNN) trained for optimal staging accuracy. The performance evaluation of the network was conducted in a five-fold cross-validation scheme. In each fold, the entire dataset was split into a training and a test set in a non-overlapping fashion between the folds (i.e., 80% and 20% of the dataset, respectively). Staging performances were calculated per tooth type and overall (accuracy, mean absolute difference, linearly weighted Cohen's Kappa and intra-class correlation coefficient). Overall, these metrics equalled 0.53, 0.71, 0.71, and 0.89, respectively. All staging performance indices were best for 37 and worst for 31. The highest number of misclassified stages were associated to adjacent stages. Most misclassifications were observed in all available stages of 31.Our findings suggest that the developmental status of mandibular molars can be taken into account in an automated approach for age estimation, while taking incisors into account may hinder age estimation., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Objectives: This in vitro study was formulated to clarify how mandibular partial edentulous distal extension involving three missing teeth affects the virtual occlusal record (VOR) accuracy, in terms of both trueness and precision, when using two different intraoral scanners (IOSs) - the Primescan (PS) and Trios 4 (TR) scanners., Methods: A typodont model missing the left mandibular second premolar, first molar, and second molar as well as the right mandibular first molar was mounted on a semi-adjustable articulator. Four implants were placed at the sites of the missing mandibular teeth. Six pairs of stainless steel markers (diameter: 0.5 mm) were affixed to the maxillary and mandibular casts in the buccal gingiva adjacent to the implants and on the facial surfaces of teeth as reference positions for measurements. The model was digitized with an inEox X5 laboratory scanner to create a reference dataset. Intraoral scans were performed with the PS and TR scanners, with each scan duplicated 10 times to generate 20 paired IOS files. Automatic VOR generation followed the bilateral buccal scan protocol, divided into PS and TR groups (n = 10). Six subgroups of linear distances between interarch markers were assessed with Geomagic Control software, comparing deviations from the reference scan. Data normality was confirmed with the Shapiro-Wilk test. Trueness was evaluated with two-way ANOVAs and pairwise comparisons performed with Tukey's test, whereas precision was assessed with the Levene test (α=0.05)., Results: The mean linear deviation (Δd) and standard deviation (SD) of VOR were both significantly affected by marker position (P < 0.001), and a significant position × scanner interaction was detected (P < 0.001). Negative mean deviations were observed for the distally extended edentulous areas in both groups. PS scans exhibited trueness that was significantly better than that for TR scans in the D16-46, D13-43, D23-33, and D27-37 subgroups (P < 0.05), whereas there were no significant differences in the D25-35 or D26-36 subgroups. PS scanning was associated with significantly better precision than TR scanning (P < 0.001), and worse precision was observed at D27-37 for both tested IOSs., Conclusions: Mandibular partial edentulous distal extension can significantly affect VOR accuracy. The type of IOS could also affect VOR accuracy depending on the area being scanned, with better overall performance observed for the Primescan device as compared to the Trios 4 scanner. Both of these IOSs tended to underestimate VOR occlusal dimensions in mandibular distally extended edentulous areas., Clinical Significance: Mandibular distal edentulous areas can contribute to occlusal dimensions that are underestimated in digital workflows, which may result in infraocclusal discrepancies that arise when performing restorations. IOSs and VOR scanning protocols should thus be carefully considered in order to minimize these risks., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier Ltd.)

Introduction: Treacher Collins syndrome is a rare congenital disease characterized by the multiple craniofacial malformations. Although the deformities affecting patients with Treacher Collins syndrome have been well characterized, the effects of these malformations to clinical severity of the syndrome are not well understood., Objective: To determine the association of specific Treacher Collins mandibular malformations with clinical severity., Design: A retrospective radiographic observational study ., Setting: Study conducted at a single institution, a quaternary craniofacial care center., Patients: 54 patients with Treacher Collins syndrome., Interventions: Computed tomography (CT), clinical photographs and medical history were included in this analysis. Mandibles were isolated from CT data and reconstructed in three dimensions using Mimics software. Cephalometric measurements were performed on CT data. Clinical severity was determined by Teber and Vincent scores. Association of craniofacial dysmorphology to clinical severity was determined by Spearman rank coefficient., Main Outcome Measures: The main results obtained were the measurements of the mandibles and the quantification of the malformations of the evaluated patients., Results: Among the most frequent findings in the sample are hypoplasia of the zygomatic complex, descending palpebral cleft and mandibular hypoplasia. Patients with a lower ramus/corpus ratio had a higher (more severe) Teber and Vincent classification., Conclusion: Patients with the most compromised mandible are also the patients with the highest number of malformations, thus, the most severe patients., Competing Interests: Declaration of Conflicting InterestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Background: Placing implants deep sub-gingivally may affect the accuracy of implant impression techniques and the fit of final restoration., Purpose: The aim of this in-vitro study was to evaluate the effect of soft tissue thickness on accuracy of conventional and digital implant impression techniques., Methods: Four parallel implant analogues (A, B, C, D) placed in each of two epoxy resin models representing edentulous mandible covered by flexible polyurethane material with two different thickness two mm and four mm. A total of sixty impressions performed, thirty impressions for each model divided into four groups (n = 15 per group) GI (C2mm) open tray impression with two mm implant depth, GII (C4mm) open tray impression with four mm implant depth, GIII (D2mm) digital impression with two mm implant depth, GIV (D 4 mm) digital impression with four mm implant depth. Impressions from open tray technique were poured to get stone casts while impressions from digital scanning technique were printed as three-dimensional printed casts. The six inter-implant distances between analogues were measured using Co-ordinate measuring machine, deviations compared to reference models were calculated. Data was collected, tabulated and statistically analyzed using One-way ANOVA test to detect significances between groups., Results: For conventional impressions there was significant difference between C2mm/C4mm (P < 0.001) regarding interimplant distance, while in digital impressions there was no significant difference between D2mm/D4mm AB(p = 0.110), BC(p = 0.066), CD(p = 0.710), AD(p = 0.084), AC(p = 0.067) and BD(p = 0.072). There was significant difference between conventional and digital impression techniques C2mm/D2mm, C4mm/D4mm (P < 0.001)., Conclusion: Within the limitations of this in-vitro study digital impressions provide more accurate outcomes with implants placed deeper subgingivally than conventional impressions., Trial Registration: Retrospectively registered., (© 2024. The Author(s).)

Objective: Distraction osteogenesis is a primary treatment for severe mandibular hypoplasia. Achieving the ideal mandible movement direction through precise distraction vector control is still a challenge in this surgery. Therefore, the aim of this study was to apply Optical See-Through (OST) Augmented Reality (AR) technology for intraoperative navigation during mandibular distractor installation and analyze the feasibility to evaluate the effectiveness of AR in a phantom experiment., Methods: Phantom was made of 3D-printed mandibular models based on preoperative CT scans and dental arch scans of real patients. Ten sets of 3D-printed mandible models were included in this study, with each set consisting of two identical mandible models assigned to the AR group and free-hand group. 10 sets of mandibular distraction osteogenesis surgical plans were designed using software, and the same set of plans was shared between the AR and free-hand groups. Surgeons performed bilateral mandibular distraction osteogenesis tasks under the guidance of AR navigation, or the reference of the preoperative surgical plan displayed on the computer screen. The differences in angular errors of distraction vectors and the distance errors of distractor positions under the guidance of the two methods were analyzed and compared., Results: 40 distractors were implanted in both groups, with 20 cases in each. In intra-group comparisons between the left and right sides, the AR group exhibited a three-dimensional spatial angle error of 1.88 (0.59, 2.48) on the left and 2.71 (1.33, 3.55) on the right, with P = 0.085, indicating no significant bias in guiding surgery on both sides of the mandible. In comparisons between the AR group and the traditional free-hand (FH) group, the average angle error was 1.94 (1.30, 2.93) in the AR group and 5.06 (3.61, 9.22) in the free-hand group, with P < 0.0001, resulting in a 61.6% improvement in accuracy. The average displacement error was 1.53 ± 0.54 mm in the AR group and 3.56 ± 1.89 mm in the free-hand group, with P < 0.0001, indicating a 57% improvement in accuracy., Conclusion: Augmented Reality technology for intraoperative navigation in mandibular distraction osteogenesis is accurate and feasible. A large randomized controlled trial with long-term follow-up is needed to confirm these findings., Trial Registration: The project has been registered with the Chinese Clinical Trial Registry, with registration number ChiCTR2300068417. Date of Registration: 17 February 2023., (© 2024. The Author(s).)

Important anatomical structures such as mandibular incisive canal, tongue foramen, and mouth floor vessels may be damaged during implant surgery in the mandibular anterior region, which may lead to mouth floor hematoma, asphyxia, pain, paresthesia and other symptoms. In severe cases, this can be life-threatening. The insufficient alveolar bone space and the anatomical variation of blood vessels and nerves in the mandibular anterior region increase the risk of blood vessel and nerve injury during implant surgery. In case of vascular injury, airway control and hemostasis should be performed, and in case of nerve injury, implant removal and early medical treatment should be performed. To avoid vascular and nerve injury during implant surgery in the mandibular anterior region, it is necessary to be familiar with the anatomical structure, take cone-beam computed tomography, design properly before surgery, and use digital technology during surgery to achieve accurate implant placement. This article summarizes the anatomical structure of the mandibular anterior region, discusses the prevention strategies of vascular and nerve injuries in this region, and discusses the treatment methods after the occurrence of vascular and nerve injuries, to provide clinical reference.

This retrospective study used cone-beam computed tomography to investigated the crown-root morphology and alveolar bone structure in incisors region in subjects with closed deep overbite and comparison the difference between gender and age. The CBCT images for 40 subjects (group C) with Angle II division 2 were selected from patients of the HeFei Stomatological Hospital from November 2023 to March 2024.20 individual normal occlusion subjects (group A),20 patients with Angle II division 1(group B) were included. The crown-root ratio of the maxillary and mandibular anterior teeth, crown-root angle and alveolar bone structure were measured on the CBCT images, the data were statistically analyzed. In addition to mandibular lateral incisor, the crown-root ratio of maxillary and mandibular anterior teeth in the Class II division 2 group was higher than that in the individual normal occlusion group and the Class II division 1 (P < 0. 05). The crown-root angle of maxillary anterior teeth in the Class II division 2 group was smaller than that in the individual normal occlusion group and the Class II division 1 (P < 0. 05). The alveolar bone thickness of the maxillary central incisor was comparatively smaller, while the alveolar bone height was relatively higher in the Class II division 2 group. Age and gender were associated with change in root lengths and crown-root angle for the Class II division 2 group (P < 0. 05). Patients with closed deep overbite malocclusion exhibit a significant difference compared to the controls for most measurements. The patients presenting with Class II division 2 malocclusion exhibit excessive inward positioning of the anterior teeth, resulting in evident crown-root angle, a large crown-root ratio, and minimal labial alveolar bone. In order to keep the tooth movement within the safe range of alveolar bone movement, it is necessary to strictly control the torque and use appropriate orthodontic force to reduce the risk of bone fenestration, bone dehiscence, gingival recession and root resorption., (© 2024. The Author(s).)

Background: The aim of this study was to compare and evaluate three AI-assisted cephalometric analysis platforms-CephX, WeDoCeph, and WebCeph-with the traditional digital tracing method using NemoCeph software., Material and Method: A total of 1500 lateral cephalometric films that met the inclusion criteria were classified as Class I, Class II, and Class III. Subsequently, 40 patients were randomly selected from each class. These selected films were uploaded to 3 AI-assisted cephalometric analysis platforms and analyzed without any manual intervention. The same films were also analyzed by an orthodontist using the NemoCeph program., Results: The results revealed significant differences in key angular measurements (ANB, FMA, IMPA, and NLA) across Class I, II, and III patients when comparing the four cephalometric analysis methods (WebCeph, WeDoCeph, CephX, and NemoCeph). Notably, ANB (p < 0.05), FMA (p < 0.001), IMPA (p < 0.001), and NLA (p < 0.001) varied significantly. Linear measurements also differed, with significant differences in U1-NA (p = 0.002) and Co-A (p = 0.002) in certain classes. Repeated measurement analysis revealed variation in SNA (p = 0.011) and FMA (p = 0.030), particularly in the Class II NemoCeph group, suggesting method-dependent variability., Conclusion: AI-assisted cephalometric analysis platforms such as WebCeph, WeDoCeph, and CephX give rise to notable variation in accuracy and reliability compared to traditional manual digital tracing, specifically in terms of angular and linear measurements. These results emphasize the importance of meticulous selection and assessment of analysis methods in orthodontic diagnostics and treatment planning., (© 2024. The Author(s).)

Objectives: Compare the accuracy and diagnostic concordance of three commercially available AI-based lateral cephalometric tracing software., Materials and Methods: Sixty-three lateral cephalometric radiographs were analyzed using semi-automatic (Dolphin Imaging Systems LLC) and AI-based software programs (WebCeph™, Cephio, and Ceppro DDH Inc.). Intra- and inter-observer reliability were assessed for human expert measurements, and repeated-measures one-way ANOVA was used to compare the AI and human expert measurements. The diagnostic performance was evaluated using sensitivity and specificity tests., Results: Human expert reliability was excellent (ICC > 0.9) for most cephalometric parameters. Compared to human experts, significant differences were observed for all three AI-based cephalometric programs (WebCeph™ - 10 of 11, Cephio - 7 of 11, and Ceppro DDH Inc. - 7 of 11 cephalometric measurements). Variations exceeding two units were noted for most parameters, and differences in defining the sagittal and vertical skeletal patterns, dental, and soft tissue characteristics were observed., Conclusion: All three AI-based tracing programs showed inaccuracies compared to human expert measurements and lacked reliability in measuring key cephalometric parameters. Clinicians should exercise caution when relying solely on AI-based analyses for orthodontic treatment planning and assessment., (© 2024. The Author(s).)

Background: Immediate implant placement (IIP) has shown predictable outcomes when specific requirements are met. The aim of the present study was to radiographically evaluate the dimensions of mandibular incisors and the alveolar bone to further determine the feasibility of IIP in this area., Materials and Methods: A total of 404 intact mandibular incisor CBCT images from 101 patients (42 males, 59 females; mean age 49 ± 16.84 years) were analyzed. The mesiodistal tooth width and the distance between the incisal edge (IE), cementoenamel junction (CEJ), facial bone crest (BC), root apex (RA), and fenestration point (F) were registered, together with the alveolar bone width at 1 and 3 mm below BC. Finally, the angular discrepancy between the dental and the alveolar bone long axis (BLA) was recorded as the tooth torque (TT)., Results: The CEJ to BC distance was 3.23 ± 1.67 mm. The RA to F mean distance was 15.02 ± 3.97 mm. The mean alveolar bone buccolingual widths at 1 and 3 mm below the facial BC were 7.12 ± 0.82 and 6.32 ± 0.71 mm in the lateral and central incisors, respectively (P 0.001). The buccolingual width was less than 6 mm in more than 33% of the central incisors, but only in 3% of the lateral incisors, displaying increased alveolar width. The average was 165.66 ± 7.47 degrees., Conclusions: The results presented in this study point toward the need for careful consideration of the requirements for anterior mandibular IIP for success and predictability purposes.

BACKGROUND The extraction of impacted supernumerary teeth requires precision and accuracy to mitigate iatrogenic damage to crucial anatomical structures during dental surgical procedures, thereby enhancing postoperative healing outcomes. Dynamic navigation systems (DNS) have been applied in dentistry in maxillofacial fractures, orthognathic surgery, root canal treatment, and endodontic surgery. CASE REPORT A 22-year-old female patient visited our department to assess and manage unerupted third molars. An initial cone beam computed tomography (CBCT) scan was obtained. Radiographic and clinical examinations showed the presence of a supernumerary tooth impacted on the lingual side between the root of the lower second premolar and the lower first molar and bilateral lower impacted third molars. The patient agreed to removal of these teeth. To perform the treatment planning of this case and to guide the surgeon intraoperatively, a dynamic surgical navigation system was recommended for surgical extraction of a supernumerary tooth and the impacted third molars. CONCLUSIONS The dynamic navigation system coupled with a high-speed contra-angle handpiece for the extraction of supernumerary teeth is a personalized, digitally-driven, precise, minimally invasive, and efficient treatment approach. In this case, the DNS and the high-speed contra-angle handpiece were seamlessly integrated to facilitate visualization of the surgical procedure, thereby safeguarding of surrounding vital anatomical structures while enhancing patient comfort.

Purpose: This study aimed to evaluate the clinical efficacy of applying real-time dynamic navigation (RDN) in the extraction of deep horizontal mandibular impacted third molars, hypothesizing that RDN reduces surgical time and minimizes the risk of injury to adjacent anatomical structures., Methods: A prospective study was conducted on 160 patients aged between 18 and 37 years with deep horizontal impaction of the mandibular third molar. The participants were randomly assigned to either the experimental group (receiving RDN-assisted extractions) or the control group (undergoing traditional extraction methods). Preoperative planning utilized cone beam computed tomography (CBCT) and Mimics software for the accurate localization and segmentation of impacted teeth. Parametric data were analysed via an independent t test for intergroup comparisons, and significance was set to p < 0.05., Results: In the experimental group, an average of 11 ± 1 min was required for preoperative planning via RDN, which was not required in the control group. The setup of the navigation system took an average of 4 ± 1 min in the experimental group and 0 min in the control group. The experimental group demonstrated a significantly shorter average surgical time (22 ± 3 min) than did the control group (36 ± 3 min). The differences in the preoperative design time, surgical time, and complication rates between the two groups were statistically significant (p = 0.005). Additionally, the RDN group reported no complications related to adjacent tooth damage or nerve injury., Conclusion: The precision, safety, real-time guidance of RDN supports its use in complicated dental extractions, which would introduce a new era of oral and maxillofacial surgery., (© 2024. The Author(s).)

Purpose: To estimate the effect of simvastatin gel in the osseointegration of dental implants using bone scintigraphy., Materials and Methods: A total of 20 participants with missing mandibular first molars and D2 type bone were assigned equally to two groups. Group A received 1.2% simvastatin and group B received placebo gels during the placement of implants. The participants were subjected to bone scintigraphy to determine the osteoblastic activity at baseline, 30 days, and 90 days after implant placement., Results: Group A had a significant increase in osteoblastic activity between baseline, day 30, and day 90 (P < .05), with a higher mean of 100.06% ± 21.644% on day 30. Group B had a significant increase in osteoblastic activity only between baseline and day 30 and between baseline and day 90 (P < .05). There was no difference between days 30 and 90 (P > .05), with a higher mean of 79.20% ± 18.255% on day 30. A bivariate analysis performed at different time periods revealed a significant difference between groups A and B on day 30., Conclusions: Implants placed with 1.2% simvastatin gel showed enhanced osteoblastic activity in the 4th week after implant placement, indicating that there was a faster rate of osseointegration at an early stage.

Purpose: This study assessed the accuracy of linear measurements and dental implant selection performed in a smartphone application compared to a computer software., Materials and Methods: Forty-four DICOM files from the posterior mandible in partially edentulous patients were evaluated by three trained and calibrated examiners. Images were analyzed using three visualization methods: cross-sectional view (CScr) and coronal (CSco) plane using the CS 3D Imaging software, and coronal (DRco) plane using the DroidRender smartphone application. For standardization, bone width and height measurements were taken in the edentulous posterior mandible, 10 mm posterior to the mental foramen. Implants were selected according to the 2022/2023Straumann Standard implant catalog. Linear measurements were compared using repeated-measures ANOVA, and implant selection was compared using Friedman test. Statistical analysis was performed using SPSS software, with a significance level of 5%., Results: Linear measurements showed a statistically significant difference for bone width (P &#61; .030), but not for height (P &#61; .685). The choice of implant was not influenced by the visualization method (P &#61; .614)., Conclusions: It is possible to suggest the use of smartphone applications as an additional diagnostic tool for DICOM evaluation and implant planning in the posterior mandible. Smartphone applications allow an assessment not limited to 2D images or to static environments. Therefore, information exchange and diagnostic opinion in emergency situations may be facilitated.

Mandibular movement is complex and individual due to variations in the temporomandibular joint (TMJ). Consequently, patient-centered dentistry should incorporate patients' specific anatomy and condylar function in treatment planning. Real-time magnetic resonance imaging (rt-MRI) visualizes relevant structures and tracks mandibular movement. However, current assessments rely on qualitative observations or time-consuming manual tracking, lacking reliability. This study developed an automatic tracking algorithm for mandibular movement in rt-MRI using least mean square registration (LMS) and compared it to manual tracking (MT) during mouth opening. Ten participants with skeletal class I underwent rt-MRI (10 frames/s). The same operator tracked the condylar pathway for the two methods, setting 2000 landmarks (2 landmarks x100 frames x10 participants) for MT and 210 landmarks (3 landmarks x7 frames x10 participants) for LMS. Time required, superimposition error, and the distance between tracked condylar pathways were compared between methods. LMS tracking was 76% faster and showed significantly better superimposition (0.0289 ± 0.0058) than MT (0.059 ± 0.0145) (p = 0.002). During one-third of the movement, the pathways tracked by both methods were more than 1 mm and 1° apart. These findings highlight the benefits of automatic condylar movement tracking in rt-MRI, laying the groundwork for more objective and quantitative observation of TMJ function., (© 2024. The Author(s).)

Background: Osteomyelitis secondary to mandibular fracture surgery is rare and complete surgical debridement of necrotic infected tissues is an optimal treatment for it. Subsequent reconstruction is required for bone defect caused by operation. Autogenous, allograft and synthetic bone graft substitutes have become widespread in bone defect treatment. Distraction osteogenesis (DO) was also applied in bone defect reconstruction, even it wasn't conventional therapy in jaw., Case Presentation: Here we report a case of a 40-year-old aged man who presented with chronic swelling and pain on the right mandibular masseteric region after mandibular angle and Le Fort II fracture surgery. In six weeks after surgery, CBCT images showed that the fracture ends hadn't heal and the fracture gap had widened significantly. The clinical diagnosis of the patient was right mandibular angle osteomyelitis. After controlling the symptoms of pain and infection with local rinses and systemic antibiotic therapy, the patient underwent segmental resection of the infected bone and DO reconstruction for bone defect simultaneously. Encouragingly, well bone healing and normal occlusion restoration was observed finally., Conclusions: DO could be a valuable alternative therapy to bone grafts for bone defect, even in the case of infection., (© 2024. The Author(s).)

Background: The impaction of mandibular lateral incisors presents significant aesthetic and functional challenges in orthodontics, including Bolton ratio discrepancies and anterior occlusal anomalies. The increasing preference for nonextraction treatment further complicates space management within the dental arch. However, the advent of digital-assisted orthodontic technologies, particularly advanced digital simulations, has revolutionized the precision and effectiveness of diagnosis and treatment planning. These technologies enable clinicians to strategically leverage natural jaw development and create the necessary space for the alignment of impacted teeth without resorting to extraction., Case Presentation: This case report details the treatment of a 12-year-old male with an impacted mandibular lateral incisor, which resulted in both aesthetic concerns and functional impairments, alongside Class II malocclusion. By employing a digital-assisted diagnostic approach, including comprehensive digital simulations, we meticulously evaluated the feasibility of a nonextraction treatment plan. The strategy centred on harnessing the patient's mandibular growth potential to expand the available space naturally. The treatment involved surgical exposure of the impacted tooth, followed by precise orthodontic traction guided by continuous digital monitoring. The integration of digital tools throughout the treatment process was crucial in achieving successful eruption and alignment of the impacted tooth, thus restoring optimal aesthetics and function without the need for extraction., Conclusion: This case highlights the transformative impact of digital-assisted technologies in the management of complex orthodontic cases, such as impacted mandibular lateral incisors. The successful integration of these advanced tools with a nonextraction treatment approach underscores their potential to significantly enhance clinical outcomes. Digital technologies not only improve the accuracy and effectiveness of treatment but also facilitate a multidisciplinary approach that elevates the standard of patient care in addressing complex orthodontic challenges., (© 2024. The Author(s).)

Background and Objectives: With the goal of identifying regions with bicortical bone and avoiding root contact, the present study proposes an innovative technique for the simulation of the insertion of mini orthodontic implants using automatic jaw segmentation. The simulation of mini implants takes place in 3D rendering visualization instead of Multi-Planar Reconstruction (MPR) sections. Materials and Methods: The procedure involves utilizing software that automatically segments the jaw, teeth, and implants, ensuring their visibility in 3D rendering images. These segmented files are utilized as study models to determine the optimum location for simulating orthodontic implants, in particular locations characterized by limited distances between the implant and the roots, as well as locations where the bicortical structures are present. Results: By using this method, we were able to simulate the insertion of mini implants in the maxilla by applying two cumulative requirements: the implant tip needs to be positioned in a bicortical area, and it needs to be situated more than 0.6 mm away from the neighboring teeth's roots along all of their axes. Additionally, it is possible to replicate the positioning of the mini implant in order to distalize the molars in the mandible while avoiding the mandibular canal and the path of molar migration. Conclusions: The utilization of automated segmentation and visualization techniques in 3D rendering enhances safety measures during the simulation and insertion of orthodontic mini implants, increasing the insertion precision and providing an advantage in the identification of bicortical structures, increasing their stability.

Background: Mandibular second molar (M2M) impaction is a clinically significant manifestation of eruption disturbance in dental development. The primary aim of this study was to investigate the impact of the three-dimensional (3D) characterization on clinical and therapeutic decisions for M2M impaction. The secondary aim was to introduce a validated 3D classification system incorporating both surgical and orthodontic parameters., Methods: Bidimensional (2D) and 3D radiological records of 15 impacted M2M were collected and deidentified. Ten experienced clinicians (5 oral surgeons;5 orthodontists) categorized each case, first based on 2D records and then with 3D scans. The degree of orthodontic and surgical difficulty in treating impacted M2M was evaluated using a novel classification system based on anatomical and radiological features. The primary outcome variable was the assessment of differences in diagnosis and decision-making protocol using 2D or 3D records, where clinical relevance ranged from 0 to 4. The secondary outcome variable was the validation analysis of the proposed 3D classification system to determine the concordance among the clinicians. Descriptive statistics and multivariable inferential analysis based on Akaike information criterion (AIC) were performed (α = 0.05)., Results: 3D examination allowed a better visualization of M2M impaction with higher clinical relevance for diagnosis of M2M root relationship to alveolar nerve and lingual plate, height to alveolar crest, depth, and inclination relative to the first molar and position relative to the third molar (range:2.69-3.43). The proposed 3D classification of M2M impaction changed clinical decisions regarding surgical-orthodontic approach, biomechanics, patient education, and treatment time estimate (range:2.59-3.33). In the validation analysis of the classification, no evidence of inter- or intra-group (surgeon/orthodontist) bias in score attribution occurred: the model with the minimum AIC was the null model (AIC = 718.04)., Conclusion: 3D evaluation of impacted M2Ms could enhance diagnostic accuracy, and a classification system was proposed and validated by a group of experienced surgeons and orthodontists with high concordance., (© 2024. The Author(s).)

The purpose of this study is to evaluate the relationship between radiomorphometric indices and fractal dimension (FD) analysis in jawbone radiographic density using Cone-Beam Computed Tomography (CBCT). The study included 87 CBCT datasets from dental patients aged 50-79. Four radiomorphometric indices (Computed Tomography Cortical Index (CTCI), Computed Tomography Mental Index (CTMI), Computed Tomography Index-Superior (CTI-S), and Computed Tomography Index-Inferior (CTI-I)) along with age, gender, remaining teeth, and mandibular bone height were evaluated. FD was assessed in trabecular bone near the mental foramen (ROI 1) and on the mandibular cortical bone (ROI 2). Relationships between indices and variables were analyzed using Pearson chi-square, Fisher's exact, one-way ANOVA, Kruskal-Wallis, and Spearman's rho tests. ANOVA showed significant differences in mandibular bone height (p = .004) and FD at ROI 2 (p = .000) across three mandibular cortex types (C1, C2, C3). Spearman's rho indicated significant correlations between FD at ROI 2 and CTMI, CTI-S, CTI-I (p = .000), and between mandibular bone height and CTMI (p = .010). The correlations of FD at ROI 2 ranged from strongest to weakest with CTCI, CTMI, CTI-S, and CTI-I. High-risk osteoporosis radiomorphometric indices are associated with FD analysis of cortical bone., (© 2024. The Author(s).)

Background: Schizophrenia is a chronic severe mental disorder characterized by impairment in cognition, emotion, perception, and other aspects of behavior. In light of the association of craniofacial dysmorphology with schizophrenia, mandibular morphology may provide clues about the role of neurodevelopment in the pathophysiology of schizophrenia. This retrospective cross-sectional study aimed to compare the mandibular morphology of patients with schizophrenia with controls using digital panoramic radiography (DPR)., Methods: 302 recorded diagnostic panoramic images obtained from 143 schizophrenia patients (98 males, 45 females), and 159 controls (73 males, 86 females), aged 18-45 years, were evaluated. Seven mandibular measurements consisting of ramus height, condylar height, gonial angle, antegonial angle, antegonial notch depth, ramal notch depth and bigonial width were measured from the DPRs in a double-blinded manner. Bivariate comparisons were carried out using the Independent t-test and Mann-Whitney U test. Logistic regression analysis was used for multivariate comparisons., Results: Linear measurements were higher while angular measurements were lower in schizophrenia patients. Regression analyses indicated that female patients had greater ramus height (OR = 1.243; P = 0.001), condylar height (OR = 1.463; P = 0.048) and bigonial width (OR = 1.082; P < 0.001); male patients had greater ramus heights (OR = 1.216; P = 0.001) and bigonial width (OR = 1.076; P < 0.001) as well as lower antegonial angle (OR = 0.908; P = 0.012) compared to their respective controls., Conclusion: Quantitative differences in mandibular morphology in schizophrenia patients versus controls deserve attention and corroborate with the concept of abnormal neurodevelopment in schizophrenia., (© 2024. The Author(s).)

Objective: The aim of the study was to develop and evaluate an automated preoperative planning algorithm based on anatomical landmark point recognition for enhancing the efficiency and intelligence of preoperative planning for mandibular angle osteotomy., Methods: A retrospective cohort of 34 patients underwent preoperative planning with this algorithm. The present algorithm was developed using a method based on anatomical marker point recognition. The efficiency, symmetry, and safety of the automated preoperative planning and esthetics were statistically analyzed by paired t test and χ2 test., Results: The results showed that the automated planning algorithm was able to achieve a great improvement in preoperative planning efficiency as well as safety and symmetry. A prospective case report of 2 patients is then reported, illustrating the safety and esthetics of the algorithm with 1-year postoperative follow-up and postoperative esthetic scores., Conclusion: This algorithm can help to improve the efficiency of preoperative planning for surgeons while ensuring safety and esthetics and can be further applied to other craniomaxillofacial personalized design surgeries in the preoperative design in the future., Competing Interests: The authors report no conflicts of interest., (Copyright © 2024 by Mutaz B. Habal, MD.)

Orthognathic surgery in patients with lip and palate clefts is challenging owing to scar tissue from primary repairs and severe deformities. In this study, we evaluated the stability of Le Fort I osteotomy with intraoral vertical ramus osteotomy (IVRO) in patients with cleft lip and palate using 3-dimensional (3D) analysis. This retrospective study comprised 14 cleft lip and palate patients (3 females, 11 males; the average age at surgery: 23.8 y) who underwent bimaxillary orthognathic surgery involving Lefort I osteotomy and IVRO. Cone-beam computed tomography (CBCT) images were obtained at preoperative (T0), 1-month postoperative (T1), and 1-year follow-up (T2) periods. The 3D analysis assessed the transitions and rotations of the maxilla and mandible using a virtual triangle. The maxilla showed stability in all directions at the 1-year follow-up with minimal relapse. The distal segment of the mandible exhibited clinically acceptable anterior (1.15 mm relapse) movements and pitch rotation (2.88° counterclockwise relapse) during the first year postoperatively. The proximal mandibular segment underwent anterior-inferior transition (1.21 and 2.01 mm, respectively) and lateral-outward rotation (4.90° and 7.51°, respectively) postsurgery, remaining unchanged 1 year postoperation. Le Fort I osteotomy with IVRO provides skeletal stability in patients with cleft lips and palates. This study demonstrated a minimal maxillary relapse and clinically acceptable movements in the distal mandibular segment during the first postoperative year. The proximal mandibular segment moved anteriorly and inferiorly, rotated laterally and outward after surgery, and remained unchanged at the 1-year follow-up., Competing Interests: The authors report no conflicts of interest., (Copyright © 2024 by Mutaz B. Habal, MD.)

Objective: To investigate the mean tooth length and root canal configuration of human maxillary and mandibular premolars in the population of Hyderabad, Pakistan, using Cone Beam Computed Tomography (CBCT)., Study Design: Observational study. Place and Duration of the Study: Department of Operative Dentistry and Endodontics, Liaquat University of Medical and Health Sciences, Jamshoro, Sindh, Pakistan, from December 2022 to March 2023., Methodology: Using retrospective analysis of CBCT scans, tooth length, the number of roots, and root canal configuration of 536 mandibular and maxillary premolars were assessed in the subpopulation of Pakistan. The data were analysed employing descriptive statistics, Chi-square tests, and One-Way ANOVA to determine the association between various factors and root canal morphology., Results: Vertucci Type 1 (one canal) was the most common configuration in maxillary premolars, with frequencies ranging from 46.3 to 52.2%. The mean length of all 8 premolars ranged from 20.56 mm to 21.58 mm. C-shaped canal configurations were observed in a small percentage of maxillary and mandibular premolars, with C1 being the most common. No significant association was found between gender and canal configuration or tooth length, and in tooth lengths among different canal configurations., Conclusion: Vertucci Type 1 was the most common configuration in maxillary premolars, followed by Vertucci Type 4. Single-rooted premolars were more prevalent, while two-root configurations were less common. C-shaped canal configurations were observed in a small percentage of premolars, with higher frequency in mandibular premolars., Key Words: Cone beam computed tomography, Dental anatomy, Endodontics, Premolars, Root canal morphology.

Objectives: Comparison of maxillary, mandibular, dental crown and root mineral density in human skeletons identified in historical excavations with today's human maxillary, mandibular dental crown and root., Methods: After the skull images were obtained, four groups were created: maxilla 1, mandible 1 from the old period, maxilla 2 from the images taken from today's patients, and mandible 2 from the images taken from today's patients. Seventeen skeletons were previously classified as young age, middle age, and older age. Among the archive tomography images, 17 images from young (15-35), middle (36-56) and older (57 and over) age images were included in the study. HU value of the desired region was calculated automatically by the device using Region of interest (ROI)., Results: In this study, 34 jaws and 68 teeth were evaluated, including 7 mandibles and 10 maxillae from the late Roman period, and 8 mandibles and 9 maxillae from today's people. The average HU value of the crowns of mandibular anterior teeth from the late Roman period was measured as 2406.0. The average HU value of the crowns of maxillary anterior teeth was found to be 3383.8. In the posterior aspect, the average crown HU value measured in the maxilla was found to be higher than that in the mandible., Conclusions: The finding showed that the density of dental tissues of ancient people, such as enamel and dentin forming the crown, and cementum and dentin forming the root, was significantly higher than today's people., Competing Interests: Conflict of interests The authors declare that they have no conflict of interests., (Copyright © 2024 The Author(s). Published by Elsevier Inc. All rights reserved.)

Lingual mandibular bone depression, also known as the Stafne bone cavity, commonly presents as an asymptomatic unilocular cyst-like radiolucency located below the mandibular canal. Surgical exploration of this lesion is relatively rare in the literature. A 49-year-old male was admitted to the hospital for a space-occupying lesion located in the right mandibular angle region and was performed surgical exploration. The content of the lesion was excised and prepared for histologic investigation, which revealed fibrous connective tissue, adhering muscle and nervous tissue with no evidence of epithelium tissue. Thus, the lesion was diagnosed as lingual mandibular bone depression. Of the various theories of the etiology of lingual mandibular bone depression, the most popular "glandular theory" seemed to be inapplicable in the present case. Providing misleading information in this case, B-mode ultrasonography was proved to be of little help in diagnosing this lesion., Competing Interests: The authors report no conflicts of interest., (Copyright © 2024 by Mutaz B. Habal, MD.)

The study aims to estimate precisely the different levels of mental loop and foramina in the Mosul population of Nineveh governorate in Iraq. It is a cross-sectional study of a previously saved database in the cone-beam computed tomography device. The study sample was 357 patients selected randomly from the database of patients at the Oral Radiology Unit at the Maxillofacial Department in Al-Salam Teaching Hospital. The study variables are mental foramen (MF) position, shape, radiograph appearance, and mental loop presence and direction. The results show that the age group from 19 to 30 years shows the highest percentage (40.1%). Females show more than half of the cases (59.7%). The MF position's highest percentage is shown in 2 areas with the slight differences. These are the long axis of first premolar and the area between first premolar and second premolar (42.6%, 40.9). According to shape variation round shapes are the uppermost percent (53.8%). More than 60% of cases (66.1%) show continuity with the inferior alveolar canal and 50% show no loop presence, and the mental nerve leaves the foramen in a perpendicular direction. In conclusion localization of the MF, nerve, and its loop precisely in both horizontal and vertical directions, both hard and soft tissues in a continuous view. Before arranging any surgical procedure, anatomic markers are crucial. To reduce the danger of harm to the foramen region, the authors thus advised cone-beam computed tomography before scheduling implant surgery, particularly in the mental region of the jaw., Competing Interests: The authors report no conflicts of interest., (Copyright © 2024 by Mutaz B. Habal, MD.)

Objectives: To propose a method for evaluating the coordination of maxillomandibular alveolar arch in transverse dimension with cone-beam computed tomography (CBCT) and to apply this method to subjects with normal occlusion at different dentition stages or transverse discrepancy., Materials and Methods: Digital data of 130 patients with normal occlusion at different dentition stages or transverse discrepancy were collected for three-dimensional reconstruction. The patients with normal occlusion were divided into Group 1 (>16 years) and Group 2 (≤16 years) based on their age. Adult patients with posterior crossbite were divided into the Group 3. According to the proposed method, the average alveolar arch coordination angle (AACA) and other parameters were analysed in each group. Group 1 was considered as the control group and compared with Group 2 and Group 3., Results: Significant differences were observed in the maxillary posterior segment width among patients with normal occlusion. Group 3 demonstrated increased AACA and mandibular alveolar arch width compared with the normal occlusion group. Pearson correlation analysis indicated a positive relationship between maxillomandibular alveolar arch widths in the normal occlusion groups, with a strong correlation between AACA and the disparity in maxillomandibular widths., Conclusion: Adults with normal occlusion exhibit significantly wider maxillary posterior alveolar arches than adolescents, with no marked difference in mandibular widths. The posterior crossbite group showed broader mandibular alveolar arches. There was a strong correlation between AACA and the difference in maxillomandibular widths. This study's method shows potential value for orthodontic transverse diagnosis., (© 2024 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Background: This study aimed to investigate the differences in the buccolingual inclination and transverse width of maxillary and mandibular first molars among different vertical facial types., Methods: In all, 78 samples were divided into three groups based on the GoGn-SN angle: the low-angle group (n = 26, mean age=24.21±5.11), average-angle group (n = 26, mean age=22.66±3.72), and high-angle group (n = 26, mean age=22.23±2.43). Cone beam computed tomography (CBCT) measurements were used to assess the buccolingual inclination of the axis of the maxillary and mandibular first molars, as well as the buccolingual inclination of the alveolar bone, the dental arch width, and the basal bone width. One-way ANOVA, the LSD test, and Pearson correlation analysis were performed., Results: The high-angle group showed significantly greater lingual inclination of the maxillary alveolar bone than the low-angle group and average-angle group (p < 0.001; p < 0.05). The difference in buccolingual inclination of the axis of the maxillary first molar and the alveolar bone was significantly greater in the high-angle group than in the low-angle group (p < 0.05). Both the maxillary and mandibular dental arch were significantly narrower in the high-angle group than in the other two groups. The mandibular basal bone was also significantly narrower in the high-angle group than in the low-angle group and average-angle group (p < 0.001; p < 0.01)., Conclusions: The alveolar bone of maxillary first molar in the high-angle group was more palatal inclined than that the low-angle group and the average-angle group, which suggests that orthodontists should pay more attention to the root-bone relationship in the high-angle group during expansion treatment to prevent bone fenestration and dehiscense., Competing Interests: Declaration of competing interest None., (Copyright © 2024 The Authors. Published by Elsevier Masson SAS.. All rights reserved.)

Objectives: The aim of this study is to presents an experimental method for surgical guide confection using an intraoral scanner to obtain a 3D model of the patient's complete denture and compare its accuracy with the conventional methodology using computed tomography., Study Design: This prospective in-vitro study used 30 polyurethane pre-manufactured mandibles which were divided into two groups, conventional technique (group I) and a new method using intraoral scanner (group II), establishing the virtually planned position of the dental implants as a control group, considered as the gold standard for postoperative comparison., Results: The difference between these methods is close to zero and not statistically significant (p > 0.05), being heigh deviation (Xh) with p:0.130 and angulation difference of dental implants between the groups (Ang) with p:0.396., Conclusion: The acquisition of stereolithography image of the prosthesis using an intraoral scanner has a clinically acceptable accuracy, being in agreement with the conventional method., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Erick Andres Alpaca Zevallos reports financial support was provided by State of Sao Paulo Research Foundation. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Masson SAS. All rights reserved.)

Objective: This study aimed to investigate and compare the mandibular radiomorphometric characteristics of patients with unilateral or bilateral cleft lip and palate (CLP) with those of individuals without CLP and to determine whether there was a difference., Design: Retrospective cohort study., Setting: Orthodontic Department in Faculty of Dentistry., Patients and Interventions: Mandibular cortical bone thickness was measured on high-quality panoramic radiographs taken from 46 patients with unilateral or bilateral CLP aged 13-15 years and 21 control patients., Main Outcome Measures: Three radiomorphometric indices [antegonial index (AI), mental index (MI), and panoramic mandibular index (PMI)] were measured bilaterally. AutoCAD software was used for MI, PMI, and AI measurements., Results: Left MI values were significantly lower in individuals with unilateral cleft lip and palate (UCLP; 0.029 ± 0.04) than in individuals with bilateral cleft lip and palate (BCLP; 0.033 ± 0.07). In addition, right MI values of individuals with right UCLP (0.26 ± 0.06) were significantly lower than those of individuals with left UCLP (0.34 ± 0.06) or BCLP (0.32 ± 0.08). No difference was observed between individuals with BCLP and left UCLP. These values did not differ between groups., Conclusions: Antegonial index and PMI values did not differ between individuals with different types of CLP or when compared with control patients. In patients with UCLP, cortical bone thickness was found to be reduced on the cleft side compared to the intact side. Patients with UCLP with a right-sided cleft had a more substantial decrease in cortical bone thickness., Competing Interests: Declaration of Conflicting InterestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

The mandibular premolars can pose a significant challenge in root canal treatment due to their complex canal system. This study investigated the prevalence of multiple roots and complex canal morphology of mandibular premolars in a selected Egyptian sub-population using cone beam computed tomography (CBCT). 283 CBCT scans (131 males, 152 females, age 18-70) included 1132 mandibular premolars (566 first, and 566 second premolars) were viewed for incidences ofvariation in root numbers and canal configuration according to Vertucci's classification. CBCT images were assessed by two endodontists, data were statistically analyzed using Fisher exact and Chi-square tests. The majority of first premolars (85.7%) exhibited a single root, whereas 14.7% had 2 roots with a significantly higher frequency in males (19.8%) than in females (9.5%) (P < .05). The most prevalent type was type I (57.8%), followed by type V (21.7%), while types II and VII made up only 1%. Types V and III were more prevalent among females, while males had a higher prevalence of types I and IV. In 2.5% of cases, mandibular second premolars were found to have 2 roots, with a higher incidence in males (P < .05). Type I canals were significantly more prevalent (90.8%) than other types, followed by type V (5.3%) (P < .05). A statistically significant gender correlation was found regarding root number and canal configuration. It is not uncommon to find mandibular first premolars with two roots in the southern Egyptian population, particularly in males. These observations may be valuable for dentists who treat Southern Egyptians, in Egypt and other countries., (© 2024. The Author(s).)

This study aimed to evaluate the relationship between the precise three-dimensional location of the third molar (M3) and mandibular angle fracture (MAF) patterns and to assess the effect of the volume ratio occupied by M3 in the mandibular angle on fracture patterns. The location of M3 was assessed in 218 patients with MAF using computed tomography reconstruction. The bone volume of the mandibular angle and the bone volume occupied by M3 were measured to calculate the volume ratio of M3 to the mandibular angle (M3/MA). MAF patterns were categorized into simple fracture (Type I), displaced fracture (Type II), and comminuted fracture (Type III) based on fracture severity. The results showed that the location of M3 significantly influenced MAF patterns (vertical position: P = .001; horizontal position: P = .002; angulation: P = .027, respectively) and the volume ratio of M3/MA was significantly higher for Type III fracture than Types I and II (P < .001). Regression analysis showed that the horizontal position and angulation of M3 and the volume ratio of M3/MA were the main predictors for comminuted MAF. A larger volume ratio (odds ratio [OR], 1.201; 95% confidence interval [CI], 1.037-1.391; P < .014), Class III position (OR, 7.978; 95% CI, 1.275-49.910; P < .026), and horizontal angulation (OR, 7.212; 95% CI, 1.028-50.581; P < .047) of the M3 were more prone to comminuted MAF than simple fracture. Our findings indicate that the location of M3 significantly affects MAF patterns, and that M3 may weaken the mandibular angle by occupying more bone space, thereby increasing the risk of a comminuted fracture., Competing Interests: Declaration of competing interest The authors declare that they have no conflicts of interest., (Copyright © 2024 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.)

Background: Patients with micrognathia undergoing mandibular distraction osteogenesis (MDO) for functional and aesthetic improvement are at significant risk for dental complications. The authors investigated the association of 2 osteotomy patterns-oblique and inverted-L-with risk to developing dentition., Methods: A senior orthodontist (H.D.N.) performed a retrospective review of dental radiographs of patients undergoing MDO with confirmed oblique or inverted-L osteotomies between 2012 and 2022. Images were assessed for evidence of missing, damaged, or displaced teeth, and proportion of affected hemimandibles by injury type and median number of affected teeth per hemimandible were compared between groups using appropriate statistical methodology., Results: Analysis included 44 patients (23 oblique, 21 inverted-L) and 85 hemimandibles (45 oblique, 40 inverted-L). Mean age at surgery was 3.1 ± 4.6 years, and mean time to imaging was 4.9 ± 4.1 years; there was no difference between groups ( P = 0.23, P = 0.34, respectively). Oblique osteotomy was associated with greater odds of missing teeth (odds ratio [OR], 13.3, P < 0.001), damaged teeth (OR, 3.2; P = 0.02), and any dental injury (OR, 39.9; P < 0.001) compared with inverted-L, as well as greater number of missing teeth (β = 0.6; P < 0.01), damaged teeth (β = 0.3; P = 0.02), and total number of affected teeth (β = 0.9; P < 0.001). There was no difference in incidence ( P = 0.5) or number ( P = 0.4) of displaced teeth between groups., Conclusions: Inverted-L osteotomies were associated with fewer dental complications compared with oblique osteotomy at all ages studied. Although longer-term follow-up and prospective data are needed before definitive recommendations can be made, these data are helpful to surgeons as they plan MDO., Clinical Question/level of Evidence: Therapeutic, III., (Copyright © 2023 by the American Society of Plastic Surgeons.)

Introduction: Studies directly relating radiological findings to the risk of postoperative wound infection (PWI) in impacted mandibular third molars (M3) are limited and poorly understood. This study aimed to clarify the radiological risk of PWI., Materials and Methods: Twenty-six patients who developed PWI after M3 extraction were retrospectively analyzed using orthopantomography (OPG) and computed tomography (CT) before M3 extraction to determine the association between M3 impaction status and PWI. These were compared with an equal number of non-infected groups. Moreover, the possibility of assessing the same risk in OPG as in CT imaging was examined., Results: Multivariate analysis identified class III and position B of the Pell and Gregory classification system as independent risk factors for PWI. On CT, an axial overlap distance (AOD) >3.5 mm was significantly associated with PWI. Furthermore, the sagittal overlap distance (SOD) and AOD of the OPG were significantly greater in group III-B. A strong positive correlation was observed between SOD and AOD., Conclusion: These results indicate that class III, position B, and an AOD >3.5 mm may be novel risk factors for M3 PWI. The strong correlation between SOD and AOD suggests that the risk assessment for PWI can be performed by evaluating OPG alone., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Masson SAS. All rights reserved.)

Purpose: Various anatomical variations of the inferior alveolar canal increase the incidence of surgical complications; Therefore, this study aimed to evaluate the frequency and configuration of bifid and trifid mandibular canals using cone beam computed tomography (CBCT) in the Turkish subpopulation., Methods: The inferior alveolar canal was evaluated on 1014 hemi-mandibles in the CBCT (I-CAT 3D Imaging System) images of 513 patients. The frequency and configuration of the bifid and trifid mandibular canal (MC) were examined. The relationship between bifid MC configuration and dental status and age groups was analyzed. The distance of the accessory canal to the buccal and lingual walls and the alveolar crest was measured. The diameter of the main canal and accessory canal was measured and its relationship with dental status and age groups was evaluated., Results: Bifid MC was found in 266 hemi-mandibles (24.7%) and 212 (41.3%) of 513 patients. The most common type of bifid MC was the retromolar canal (87 sides), followed by the forward canal without confluence (41; 4%) and the dental canal (34; 3.4%). 10 of the dental canals were opening to the 1st molar, 14 of the 2nd molars, and 10 of the 3rd molars. The number of retromolar foramina was 1 on 56 sides, 2 on 15 sides, and 3 on 4 sides. Forward canal without confluence was more common in edentulous patients than in dentulous patients, while the dental canal was more common in dentulous patients. The main canal diameter was 3.53 ± 0.97 mm and the bifid MC diameter was 1.82 ± 0.70 mm. Distance of the bifid MC to the lingual wall was higher in the > 64 years group than in the 18-39 years group (p = 0.022). Distance of the bifid MC to the alveolar crest was lower in the > 64 years group compared to the 18-39 years group and 40-64 years group (p = 0.015). The main canal diameter was higher in the 40-64 years group than in the 18-39 years group (p = 0.012)., Conclusion: Bifid MC has a high prevalence, occurring in almost one in two patients. Dental and retromolar types, which are close to the teeth, are more common, and this increases the possibility of complications. CBCT is the most accurate imaging technique used to detect and define these variations., (© 2024. The Author(s), under exclusive licence to Springer-Verlag France SAS, part of Springer Nature.)

Introduction: This prospective study evaluated the effect of immediate functional loading (IFL) of a full-coverage prosthesis on the clinical and radiographic outcome of nonsurgical endodontic therapy (NSET) performed on mandibular molar teeth with pulp necrosis and asymptomatic apical periodontitis., Methods: In 20 subjects, standardized 2-visit NSET was performed in bilateral mandibular first molar teeth (split-mouth model) with a diagnosis of pulp necrosis and asymptomatic apical periodontitis exhibiting a radiographic periapical index (PAI) score ≥3. In each subject, the nonvital bilateral mandibular first molar teeth were randomized to 1 of 2 groups: the IFL group or the functional loading after a time interval of 6 months group. Provisional full-coverage prostheses were provided within 7 days after the completion of endodontic therapy. The cases were followed up clinically and radiographically at 6 and 12 months. Radiographs were assessed for periapical healing based on PAI scores, which were dichotomized as healed (PAI score ≤2) or nonhealed (PAI score ≥3). The data were compared using chi-square and Fisher exact tests., Results: A recall rate of 100% was achieved at the end of 12 months. All teeth in the IFL group and the functional loading after a time interval of 6 months group were clinically asymptomatic. According to an intergroup comparison between the proportion of teeth healed and nonhealed (radiographic), there was a significant difference (P < .05)., Conclusions: IFL of a full-coverage prosthesis in endodontically treated mandibular molar teeth with pulp necrosis and asymptomatic apical periodontitis delayed periapical healing., (Copyright © 2024 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.)

Statement of Problem: Studies are sparse on how splinting scan bodies or incorporating 3-dimensionally (3D) printed scan aids influence the trueness of complete arch digital scans., Purpose: The purpose of this in vitro study was to compare the trueness of multisite implant recordings obtained using 6 different methods on an edentulous mandible., Material and Methods: A definitive cast of an edentulous mandible with 4 multi-unit analogs placed at different angles and interanalog distances was extraorally scanned, and the resulting data were saved as a reference file. To obtain experimental files, 6 distinct methods were used: conventional impression with splinted open-tray impression copings (IC), intraoral scanning (IOS) without splinting scan bodies or using any scan aids (SB), IOS with pattern resin-splinted scan bodies (PR), IOS with composite resin-splinted scan bodies (CR), IOS with 3D printed custom scan bodies (CSB), and IOS with 3D printed auxiliary apparatus (AA). The experimental files were aligned to the reference file in a metrology software program. The 3D comparison algorithm was run to quantify the root mean square estimate error (RMS). Scan bodies in the files were converted to hollow virtual cylinders, and the Cartesian coordinates of the lines passing through the centers of these cylinders were recorded to analyze angular (AD) and linear distortion (LD). LD was further analyzed along the x (∆X), y (∆Y), and z axes (∆Z). One-way ANOVAs with the Tukey HSD test were used for statistical analysis (α=.05)., Results: AD at all sites, LD at all sites, and the RMS error showed significant differences (P<.05). The IC group showed the lowest AD values across all sites, followed by the AA, CSB, PR, CR, and SB groups. The SB group had the greatest LD values at all sites, while the IC group indicated the lowest LD values at all sites except the left anterior site. In terms of 3D distortions, the SB group had the largest RMS value, whereas the IC group showed the lowest RMS value. ∆X, ∆Y, and ∆Z values also showed significant differences at all sites (P<.001) except for the ∆Z values at the right anterior site (P=.194). The highest mean ∆X, ∆Y, and ∆Z values were recorded in the SB group except for the ∆Z measurement of the left posterior site., Conclusions: The IC group outperformed the other groups. The AA group exhibited distortion comparable with that of the IC group. Splinting scan bodies or using scan aids enhanced the trueness., (Copyright © 2024 Editorial Council for The Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

Introduction and Aims: Violations of the mandibular canal (MC) and mental foramen (MF) and subsequent injuries to their neurovascular bundle have been reported after surgical and nonsurgical dental procedures. Besides using advanced technologies such as cone-beam computed tomography (CBCT), clinicians should be aware of the anatomy and location of MC and MF in different populations. This study aims to describe the morphologic characteristics of the MF, MC, and its intrabony location in relation to the apices of mandibular posterior teeth in an Emirati subpopulation using CBCT., Methods: A total of 3700 CBCT scans were screened, and 154 scans that met the inclusion and exclusion criteria were randomly selected. The scans were assessed using 3-dimensional multiplanar imaging for the following structures: the location of MF and the MC course, its intrabony location, and its relationship to the apices of the mandibular posterior teeth. The data were analysed statistically using SPSS software., Results: The MC ran lingually and inferiorly at the posterior region and became more buccal and superior towards the MF. The distal root of the mandibular second molar was found to be the closest root to the MC (2.06 ± 1.83 mm). Moreover, the most common location of the MF was distal to the contact area between the 2 premolars (0.83 ± 1.84 mm) with a significant negative correlation to age (with and increase in age, the MF moves distally). The distance between the root apices and the MC was statistically significantly affected by age (positive correlation) and gender (male patients had a greater distance)., Conclusions: The common course of the MC is lingual and inferior posteriorly and becomes more buccal and superior towards the MF, which is located mostly between the mandibular first and second premolars. Furthermore, the distal root of the mandibular second molar is the closest to the MC and has a positive relationship with age., Competing Interests: Conflict of interest None disclosed., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

The presence of foreign bodies in the mandible is not listed as a risk factor or absolute contraindication for implant rehabilitation. However, possible complications caused by foreign bodies, such as infection and cyst formation, could lead to implant failure. The authors report a case of dental implant placed 4 months after the surgical removal of embedded amalgam in the mandibular alveolus using a trephine bur and bone grafting with mineralized freeze-dried bone allograft. Clinical and radiographic evaluations were performed at each appointment to assess factors such as pain, implant mobility, probing depth, and marginal bone loss around the implant. Within 3 years of implant placement, there were no clinical signs and symptoms and no obvious radiographic marginal bone loss. Dental implant installation appears to be safe following the elimination of foreign materials, so long as anatomic and biological factors and appropriate implant choice, are taken into consideration., Competing Interests: The authors report conflicts of interest., (Copyright © 2024 by Mutaz B. Habal, MD.)