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Purpose: To compare the peri-implant bone loss of mandibular complete-arch implant-supported fixed prostheses (FPSs) supported by three and four implants and to correlate with the size of the horizontal and vertical distal cantilever at prosthesis placement (T1) and after 1 year (T2). Materials and Methods: A total of 72 external hexagon (EH) type implants were placed in 20 participants. Of these, 24 supported an FPS with three implants (G3I) and 48 with four implants (G4I). The mandibular implants were named 1, 2, 3, and 4 according to their location in the arch, in a clockwise direction. Digital periapical radiographs were taken at times T1 and T2 for analysis and measurement of peri-implant bone loss. The horizontal and vertical distal cantilevers were measured with a digital caliper and correlated with peri-implant bone loss. Results: The survival rate of implants in G3I was 91.66%, and in G4I it was 97.91%. The mean bone loss in G3I was 0.88 ± 0.89 mm, and in G4I it was 0.58 ± 0.78 mm (P = .225). There was no correlation between distal horizontal cantilevers and bone loss in the studied groups, with G3I being -0.25 (P = .197) and G4I -0.22 (P = .129). Larger vertical cantilevers of implants 1 (P = .018), 3 (P =.015), and 4 (P = .045) correlated with greater bone loss in G4I. Conclusions: The number of implants in an FPS did not influence peri-implant bone loss after 1 year of follow-up. Larger vertical cantilevers influenced greater bone loss in complete-arch implant-supported fixed prostheses supported by four implants. [ABSTRACT FROM AUTHOR]

Purpose: To compare the biomechanical responses of a normal mandible to an osteoporotic mandible with two-implant--supported magnetic attachments. Materials and Methods: A 3D finite-element model of a two-implant--supported mandibular overdenture with magnetic attachments was developed, and normal and osteoporotic bone samples were prepared. Four types of load were applied to the overdenture in each model: 100 N vertical and oblique loads on the right first molar, and a 100 N vertical load on the right canine and incisors. Biomechanical behaviors of the peri-implant bone, implant, and mucosa were recorded. Maximum equivalent stresses and elastic strains were analyzed. Results: Equivalent elastic strain in osteoporotic cortical and cancellous bone was 9% to 71% and was 142% and 207% greater than in normal cortical bone, respectively. Equivalent elastic strain in the first molar oblique loading condition was 101% to 190% greater than in the first molar vertical loading condition. Conclusions: Osteoporotic cancellous bone was weaker and less resistant to deformation than normal bone, and oblique loading was more harmful than vertical loading. [ABSTRACT FROM AUTHOR]

Background: Relapses following orthognathic surgery have been reported to exceed 2% to 50%, depending on multiple factors. This study aimed to analyze the stability after orthognathic surgery in patients with mandibular ramus height asymmetry through 3D reconstruction using Cone-beam CT. Methods: This retrospective cohort study investigated patients who underwent mandibular setback surgery using bilateral sagittal split ramus osteotomy. Three-dimensional CT scans were taken at three different time points. Evaluation of the postoperative stability involved measuring changes in the x, y, and z axes as well as roll and yaw rotations of the mandible at specific landmarks (B point, mental foramen) on 3D CT scans obtained immediately after surgery and 6–12 months postoperatively. They were categorized into four groups based on bilateral mandibular height asymmetry through Asymmetry index (AI). The one-way ANOVA was implemented to compare the intergroup differences and Tukey's post hoc test was employed. Additionally, the Pearson correlation coefficient was also calculated. Results: A total of 24 patients were included in this study. The corresponding AI, representing the degree of asymmetry in both mandibles, were calculated as Group 1 was 1.25 ± 0.64%, Group 2 was 2.89 ± 0.47%, Group 3 was 5.03 ± 0.51%, and Group 4 was 9.40 ± 1.99%. The x-axis change in Group 4 was significantly larger at 1.71 mm compared to Group 1 at 0.64 mm. The mandibular roll, Group 4 showed a statistically significant increase at 1.33° compared to Group 1 at 0.35°. And there was a significant positive correlation observed between x-axis change and AI (p = 0.019), as well as between mandibular roll and AI (p = 0.025). Conclusion: After orthognathic surgery, stability was influenced by numerous factors, with the findings of this study suggesting that the degree of ramus height asymmetry in the mandible can be considered one contributing factor. [ABSTRACT FROM AUTHOR]

Objective: To apply the more accurate technique for mandibular superimposition and provide a valuable reference for the assessment of mandibular tooth movement and condylar remodeling before and after orthodontic treatment. Methods: This retrospective study involved 38 adult patients who underwent two cone beam computer tomography (CBCT) scans at different stages of treatment at Fujian Provincial People’s Hospital between September, 2020 and December, 2022. The software Dolphin was used for mandible segmentation, enabling voxel‐based mandibular superimposition with the mandibular ramus as the reference region. The Geomagic Wrap software was employed to process surface‐based mandibular superimposition with the mandibular ramus as a reference. Additionally, the voxel and surface‐based methods were compared for precision, with the mandibular ramus being the reference. Results: After voxel‐based mandibular superimposition using the mandibular ramus as a reference, with all measurement errors (< 0.20 mm). In contrast, the results of surface‐based mandibular superimposition with the same reference, and the measurement errors were all less than 0.10 mm. The Wilcoxon signed‐rank test revealed statistically significant differences between AS1 and BS1, AS2 and BS2, AS3 and BS3, and AS4 and BS4 (all r< 0.05). Moreover, the absolute mean distances of AS1-AS4 were all greater than those of BS1-BS4. Conclusion: All mandibular superimposition procedures, including the voxel‐ and surface‐based ones using the mandibular ramus as a reference, have acceptable surface errors (< 0.20 mm), indicating the good reliability of these techniques. Under the specified conditions, surface‐based mandibular superimposition appears to yield a higher degree of precision compared with the voxel‐based technique. [ABSTRACT FROM AUTHOR]

Schwannomas are benign peripheral nerve sheath neoplasms that grow slowly and arise from Schwann cells. Here we report a case of an intraosseous schwannoma, with recent updates of molecular characterization and immunohistochemical data, affecting the left mandibular ramus featuring multilocular well-defined radiolucency making it difficult to diagnose. [ABSTRACT FROM AUTHOR]

Objective: To investigate the accuracy of artificial intelligence‐assisted growth prediction using a convolutional neural network (CNN) algorithm and longitudinal lateral cephalograms (Lat‐cephs). Materials and Methods: A total of 198 Japanese preadolescent children, who had skeletal Class I malocclusion and whose Lat‐cephs were available at age 8 years (T0) and 10 years (T1), were allocated into the training, validation, and test phases (n = 161, n = 17, n = 20). Orthodontists and the CNN model identified 28 hard‐tissue landmarks (HTL) and 19 soft‐tissue landmarks (STL). The mean prediction error values were defined as 'excellent,' 'very good,' 'good,' 'acceptable,' and 'unsatisfactory' (criteria: 0.5 mm, 1.0 mm, 1.5 mm, and 2.0 mm, respectively). The degree of accurate prediction percentage (APP) was defined as 'very high,' 'high,' 'medium,' and 'low' (criteria: 90%, 70%, and 50%, respectively) according to the percentage of subjects that showed the error range within 1.5 mm. Results: All HTLs showed acceptable‐to‐excellent mean PE values, while the STLs Pog', Gn', and Me' showed unsatisfactory values, and the rest showed good‐to‐acceptable values. Regarding the degree of APP, HTLs Ba, ramus posterior, Pm, Pog, B‐point, Me, and mandibular first molar root apex exhibited low APPs. The STLs labrale superius, lower embrasure, lower lip, point of lower profile, B′, Pog,' Gn' and Me' also exhibited low APPs. The remainder of HTLs and STLs showed medium‐to‐very high APPs. Conclusion: Despite the possibility of using the CNN model to predict growth, further studies are needed to improve the prediction accuracy in HTLs and STLs of the chin area. [ABSTRACT FROM AUTHOR]

Aim Materials and Methods Results Conclusion To evaluate the performance of low‐dose cone beam computed tomography (CBCT) protocols with regard to linear bone measurements in the posterior mandible for implant planning compared with higher dose protocols.Forty‐two edentulous posterior sites in human cadaveric mandibles were imaged in three CBCT scanners using three or four protocols with varying exposure parameters to achieve lower dose. Co‐registration was performed to generate sagittal and cross‐sectional image sections representative of the implant site. Three observers measured bone height, from the alveolar crest to the mandibular canal, and width, three mm from the top of the alveolar crest. Intra‐ and interobserver reproducibility were assessed for the cases rated as nonmeasurable as well as for completed measurements. The measurements were analyzed using paired t‐tests for differences among the CBCT protocols and the frequency distribution of nonmeasurable cases with a Pearson Chi‐square test.Reproducibility for registering nonmeasurable cases varied among observers; however, no consistent significant differences were found in the frequency distribution of these cases among observers, units, and protocols. Intraclass correlation coefficients (ICC) were >0.9 for all measurements of bone height and width. Mean differences of <0.5 mm were found regardless of protocol; however, one observer did in some cases produce larger differences.Linear bone measurements did not differ significantly and could be performed with excellent reliability, using low‐dose CBCT protocols compared with standard and high‐resolution ones. Varying approaches for rating nonmeasurable cases were found, indicating differences in diagnostic strategies related to implant planning among observers. [ABSTRACT FROM AUTHOR]

Purpose: To assess the presence of mandibular canal bifurcation (BMC) and classify these variations by correlating findings with sex, age and facial skeletal pattern, measurements were made, including height, width, and distance from bifurcation to anatomical cortical bones. Methods: BMC was identified in cone beam CT exams of 301 patients and classified according to its origin, location, direction, configuration and ending. The height and width of the MC before and after the bifurcation; height and width of the BMC; and distance from BMC to alveolar (C1), buccal (C2), lingual (C3) and basal (C4) bone cortices were measured. All data were correlated with sex, age, and facial skeletal pattern (class I, II, III). The significance level was 5%. Results: 67 BMC (22.26%) were identified in 55 patients (18.28%). Bifurcations were more prevalent in females (p = 0.57), aged 18–39 years (p = 0.40), class I (p = 0.77). Single bifurcations, located in the posterior region of the mandible, originating in the MC, with a superior direction and ending in the retromolar foramen were more prevalent (p > 0.05). Mean cortical measurements were higher in male individuals, with significant differences only at C1 (p = 0.03). The mean height and width of BMC were 2.24 (± 0.62) and 1.75 (± 0.45) mm. There was no association between BMC classification and the variables studied (p > 0.05). Conclusion: Approximately 1/5 of the population studied had BMC. There were no associations of BMC presence or characteristics with sex, age, and facial skeletal pattern. The distance from bifurcation to alveolar (superior) cortical bone is greater in male individuals. [ABSTRACT FROM AUTHOR]

To compare craniofacial and cervical morphology between skeletal Classes II and III applying Geometric Morphometric Methods (GMM). Twenty-six cervical and craniofacial landmarks of 40 Class II and 39 Class III individuals were digitalized on lateral cephalograms. Procrustes ANOVA, generalized Procrustes, principal component analyses, and thin-plate spline function were applied to assess the pattern of shape variation of craniofacial structure and the cervical spine in relation to skeletal classes. Compared with Class III, Class II individuals presented a maxillary protrusion, mandibular retrusion, shorter mandibular corpus, posterior mandibular ramus rotation, anterior cranial base rotation, and a smaller centroid size. Furthermore, a forward and smaller cervical spine were observed. With GMM, the shape and size differences between skeletal classes can be analyzed visually and numerically. [ABSTRACT FROM AUTHOR]

Aims: The present aim was to evaluate vertical cephalometric characteristics in populations with Turner syndrome (TS) using meta‐analysis methodology. Methods: Six electronic databases were queried, up to August 2023, to identify studies comparing the vertical cephalometric characteristics in populations with TS, compared to female control groups. Data were extracted from eligible studies and random‐effects meta‐analysis was employed. Subgroup meta‐analyses for age and karyotype were also attempted. Risk of bias was assessed using a modified version of the AXIS tool. Results: From the initial 195 studies identified, 17 were included in the quantitative synthesis, resulting in a sample of 417 patients with TS, originating from 10 different countries. Risk of bias was overall questionable. Mandibular ramus height was found to be smaller in females with TS, along with a reduction in posterior facial height, a larger anterior‐posterior facial height ratio, and an increase in the mandibular plane angle. Subgroup meta‐analyses showed that females with the monosomy X karyotype had vertical cephalometric characteristics which deviated more from the norm than those with other karyotypes. Conclusion: The vertical lateral cephalometric characteristics of females with TS differ significantly from those of non‐syndromic females, with the largest and most consistent deviation being seen in the monosomy X karyotype. Females with TS show less craniofacial posterior vertical development, with an evident reduction in mandibular ramus height leading to the cephalometric characteristics observed. [ABSTRACT FROM AUTHOR]

Background: The mandible, being a robust bone, remains intact postmortem and can be utilized for gender determination. Morphometric analysis of the mandibular ramus holds significance for anthropologists, anatomists, and prosthetists. This study aims to assess the height and breadth of the mandibular ramus and their association with gender. Materials and Methods: The study was conducted on 56 cadaveric mandibles (18 female and 38 male). The height and breadth of the mandibular ramus were measured.Results: The mean ± SD for ramus height and breadth on the right side for females was 41.18 ± 4.70 mm and 28.89 ± 2.28 mm, respectively, while on the left side, it was 43.03 ± 3.57 mm and 30.70 ± 7.62 mm, respectively. For males, the mean ± SD for ramus height and breadth on the right side was 47.34 ± 2.88 mm and 33.14 ± 3.26 mm, respectively, while on the left side, it was 47.39 ± 3.88 mm and 32.39 ± 3.85 mm, respectively. Conclusion: The mean ± SD for ramus height and breadth was greater in males than in females. Although this study was conducted on cadaveric mandibles, the mandibular ramus can be utilized for gender determination in medico-legal and forensic cases.Keywords: gender, mandible, morphometry, mandibular ramus

The aim of this study was to evaluate healing at the donor site following autogenous block graft harvesting from the mandibular ramus. In this retrospective study, cone beam computed tomography images taken at different time-points were examined, and the volumes of preoperative and postoperative regions of interest were calculated in the software. Images were classified into four groups: 0–3 months, 4–6 months, 7–12 months, and >12 months post-surgery. To characterize the healing process over time, statistical analyses were conducted for both the 70% and 80% healing thresholds. Nearly half (n = 15, 47%) of the 32 patients included in this study achieved 70% bone healing within 4–12 months post-surgery. At the end of the 28-month period covered by this study, 21 patients (66%) had achieved 70% bone healing. The median time to achieve 70% healing was 9 months, while the median time to achieve 80% healing was 28 months. The findings of this study validate the feasibility of reutilizing the mandibular ramus area for additional bone augmentation when other intraoral sites are unavailable. [ABSTRACT FROM AUTHOR]

Background: Defects of the ascending ramus of the mandible, including the condylar head and neck or the whole temporomandibular joint (TMJ), are difficult to reconstruct. Reconstruction is mainly based on the use of alloplastic joint prosthesis, costochondral grafting, distraction osteogenesis of the dorsal part of the mandibular ramus, or osseous microvascular flaps of various origin. With the objective of developing a method that overcomes the restrictions of these methods, we recently introduced a sequential chimeric flap consisting of a lateral femoral condyle flap (LFC) and deep circumflex iliac artery flap (DCIA) for reconstruction of up to half of the mandible and the condylar head and neck. Methods: The chimeric flap was used in four patients with the following diagnoses: therapy-refractory osteomyelitis, extended recurrent odontogenic keratozyst, Goldenhar syndrome, and adenocarcinoma of the parotid gland. After a diagnostic workup, LFC and DCIA flaps were harvested in all patients and used in a sequential chimeric design for the reconstruction of the mandibular body and condylar head and neck. Results: Follow-up from at least 24 months up to 70 month after surgery showed a successful reconstruction in all four patients. The LFC provided a cartilaginous joint surface, allowing for a satisfactory masticatory function with a stable occlusion and unrestricted mouth opening and preserved or regained lateral and medial excursions in all patients. The DCIA allowed for a bony reconstruction anatomically resembling a non-atrophied mandibular body. No flap-related complications were observed. Conclusions: The sequential chimeric LFC and DCIA flap is an appropriate method for reconstructing up to half of the mandible and the condylar head and neck. It is suitable in cases where alloplastic joint replacement cannot be used or where other methods have failed. Due to the necessity of harvesting two flaps, the burden of care is increased, and a careful indication is required. The technique is reserved for maxillofacial surgeons who have already gained significant experience in the field of microsurgery. [ABSTRACT FROM AUTHOR]

Objectives: Dental anthropological investigations into sexual dimorphism have conventionally concentrated on evaluating the dimensions and configuration of the enamel cap of canines. However, the morphology of the crown dentine surface can be closely linked to that of the enamel surface. This link can facilitate examination of crown morphology even when the enamel surface is slightly worn. Here, we determine if the morphology of the enamel‐dentine junction (EDJ) differs within (maxillary vs. mandibular) and between a sample of male (n = 26) and female (n = 21) contemporary human permanent canines from Europe. Methods: The morphological data of the EDJ were gathered employing a template comprising 96 landmarks and sliding semilandmarks. Subsequently, the data underwent analysis through form space principal component analysis following Procrustes registration, utilizing standard 3D geometric morphometric techniques. Results: Significant differences in the morphology of the EDJ were observed between the sexes, particularly concerning the overall shape of the crown, the symmetry of the mesial and distal edges, and the development of the distal accessory ridge. Conclusions: Sex differences in the morphology of the EDJ could relate in part to retention of the canine‐premolar honing complex in males. Our results indicate that analyses of the permanent canine EDJ may potentially provide a novel method for estimating the sex of adult and nonadult skeletons. [ABSTRACT FROM AUTHOR]

Objectives: This study aimed to determine the prevalence of anterior extensions of the parotid gland (AEPG), namely the accessory parotid gland (APG) and the facial process of the parotid gland (FP), using ultrasonography. Study design: A total of 338 parotid glands were scanned bilaterally. APG was defined as a soft tissue mass with the same echogenic features as the main parotid gland (MPG) and not in contact with it, while FP was defined as an extension that exceeded the anterior border of the mandibular ramus and was continuous with the MPG. The anteroposterior, mediolateral, superoinferior dimensions and the mean distance from the MPG to the APG were measured. Results: The prevalence of APG and FP were 19.5% and 36%, respectively, resulting in an AEPG prevalence of 55.6%. The presence of APG was statistically higher in females than in males (p = 0.039). The mean anteroposterior, mediolateral, and superoinferior dimensions of the APG were 18.1 ± 0.57 mm, 0.35 ± 0.17 mm, and 12.3 ± 0.36 mm, respectively, and the mean distance from the MPG was measured as 12.1 ± 0.87 mm. Conclusion: This study can raise awareness among clinicians about the presence of AEPG in the differential diagnosis of mid-cheek masses. [ABSTRACT FROM AUTHOR]

Study Design. Anatomical study. Objective. This study aimed to elaborate on the anatomical characteristics of the medial branch of the lumbar dorsal rami and to discuss its possible clinical significance. Summary of Background Data. Radiofrequency ablation targeting the medial branch of the lumbar dorsal rami has been increasingly used in the clinical management of facetogenic low back pain (FLBP). Nonetheless, attention is also being given to complications such as atrophy of the lumbar soft tissues and muscles. Therefore, a more detailed understanding of the innervation pattern on the facet joint may improve the precision of nerve ablation therapy for FLBP. Methods. An anatomical study of eight human specimens was carried out. The anatomic characteristics of the medial branch were observed and recorded. Results. The medial branch originates from the lumbar dorsal rami, running close to the root of the posterolateral side of the superior articular process of the inferior cone. When passed through the mamillo-accessory ligament, it turns direction to the medial and caudal side, running in the multifidus muscle. In our study, each medial branch sent out two to five branches along the way. All the medial branches in L1-L4 gave off one to two small branches when crossing the facet joint and innervated the joint of the lower segment. Nineteen medial branches (23.75%) gave off recurrent branches to innervate the joint at the upper segment. Conclusion. The anatomical features of the medial branch remain similar in each lumbar segment. There are two types of joint branches, including the articular fibers that emanate from the medial branch as it runs along the medial border of the facet joint and the recurrent branch from the medial branch that innervates the upper facet joint. Moreover, an anastomotic branch was found in the medial branches between different segments. [ABSTRACT FROM AUTHOR]

Primate mandibular morphology is often associated with jaw functionality of the masticatory complex in the context of variation in diets. Recent research into the disparities between the diet and jaw functionality in male and female hominoids is inconclusive and suggests that sexual dimorphism in the mandible may be influenced by external factors such as temporalis and masseter muscle morphology, which in turn may be influenced by sexual selection. As the muscles associated with mastication (i.e., the type of chewing exhibited by primates and other mammals) encompass the mandible as well as the neurocranium, including the sagittal crest among some individuals, this study investigates sex‐specific associations between regions of the mandibular ramus and neurocranium associated with mastication in a dentally mature sample of Gorilla and Pongo. A total of four cranial and mandibular variables were measured in two Gorilla taxa (Gorilla gorilla gorilla and Gorilla beringei graueri) and one Pongo taxon (Pongo pygmaeus pygmaeus) (n = 220). For all three taxa, we investigate (a) whether the degree of sexual dimorphism in cranial regions associated with sagittal cresting (sagittal crest size (SCS) and temporalis muscle attachment area (TMAA)) is proportional to the degree of mandibular ramus area (MRA) and coronoid process height (CPH) sexual dimorphism, (b) whether there are sex differences in scaling relationships between TMAA and MRA, and (c) whether there are sex differences in the strength of association between TMAA and CPH. We show that for G. g. gorilla, variables associated with sagittal cresting show higher sexual dimorphism values than our two mandibular ramus variables, which is not the case for G. b. graueri or for P. p. pygmaeus. All three taxa show similar sex‐specific scaling relationships between TMAA and MRA, where for males this relationship does not diverge from isometry, and for females there is a negative allometric relationship. Our findings also show intraspecific sex differences in allometric slopes between MRA and TMAA for all three taxa. Only G. g. gorilla shows a significant association between TMAA and CPH, which is observed in both sexes. Although there are some statistical associations between the cranial and mandibular regions associated with mastication, our results show that among male gorillas and orangutans, patterns of variation in the sagittal crest, TMAA, mandibular ramus and the coronoid process cannot be explained by the muscle attachment hypothesis alone. These findings have implications surrounding the associations between social behaviour and the morphology of the craniofacial complex. [ABSTRACT FROM AUTHOR]

This study aimed to evaluate maxillary bone healing and computed tomography (CT) values after Le Fort I osteotomy with sagittal split ramus osteotomy in patients with class II and III malocclusion. Four absorbable plates and screws were used to fix the maxillary segments in all patients. For 112 sides (58 patients), the bone defect areas at the anterior and posterior sites between the maxillary segments were measured using 3-dimensional CT views reconstructed over a constant CT value at 1 week and 1 year postoperatively. Subsequently, CT values at the upper, middle, and lower sites around the osteotomy line in the medial, middle, and lateral regions were measured. The bone defect area after 1 year increased at the anterior site in class III and at both the anterior and posterior sites in class II (P < 0.05). This study suggests that the increase in bone defect area was affected by lower CT values at the middle site of the middle and lateral regions in class II, and that bony defects between fragments in the maxilla could partially remain in both classes II and III within 1 year after Le Fort I osteotomy. [ABSTRACT FROM AUTHOR]

Background: The condylar process of mandible is an ellipsoid hard tissue (bony structure) with a thin neckline that joins to the mandibular ramus. The condylar processes are a critical anatomic component of the mandible that development of mandibular bone is attributed in the sagittal and vertical directions by condylar process. Objective: To radiographical assessment of condylar head measurements according to gender and site by uses cone beam computed tomography. Patients and Methods: The study samples consisted of sixty-five individuals (19 male and 46 female) with age range from (20-50) years old. Width of condylar head, length of condylar head and condylar head height were measured in the study by using cone beam computed tomography from radiology archive in specialist dental center in Diyala. Results: The results show condylar head width, condylar head height and condylar head length in sides (right and left), males have noted higher mean value than females. The results show condylar head width and condylar head length in left side, have recorded higher mean value than right side. While, condylar head height in left side, have recorded lower mean value than right side. Conclusion: Condylar dimensions and sizes may be associated with gender and site. Males have higher condylar dimensions and sizes than females. [ABSTRACT FROM AUTHOR]

Elective mandibular surgical osteotomies are commonly used to correct craniofacial discrepancies. Since the modifications proposed by Obwegeser, Dal Pont, and Hunsuck, no effective variations have been proposed to improve the biomechanical results of these mandibular osteotomies. With technological developments and the use of three-dimensional images from CT scans of patients, much has been done to plan and predict outcomes with greater precision and control. To date, 3D imaging and additive manufacturing technologies have not been used to their full potential to create innovative mandibular osteotomies. The use of 3D digital images obtained from CT scans as DICOM files, which were then converted to STL files, proved to be an efficient method of developing an innovative mandibular ramus beveled osteotomy technique. The new mandibular osteotomy is designed to reduce the likelihood of vasculo-nervous damage to the mandible, reduce the time and ease of surgery, and reduce post-operative complications. The proposed osteotomy does not affect traditional osteotomies. Anatomical structures such as the inferior alveolar nerve and intraoral surgical access were preserved and maintained, respectively. The results obtained from the digital images were validated on an additively manufactured 3D synthetic bone model. [ABSTRACT FROM AUTHOR]

Objective: To describe the mandibular growth of craniofacial microsomia (CFM) patients during early childhood to adolescence with attention to symmetry. Materials and Methods: Altogether 61 CFM patients were studied at the Cleft Palate and Craniofacial Center, Helsinki University Hospital between 1986 and 2006. In this cohort study, we measured and analysed 293 radiographs (posteroanterior, panoramic and lateral); 165 radiographs of 40 patients met the final inclusion criteria. The vertical height of the ramus in anteroposterior and panoramic radiographs, the length of the mandible in anteroposterior radiographs and the maxillary protrusion and mandibular retrognathia in lateral cephalograms were measured in four different age groups. Results: A statistical difference existed between the groups in the vertical height of the ramus and in the mandibular length. The vertical height of the ramus measured from the panoramic radiograph grew on both sides, and the ratios remained unchanged. In the sagittal dimension, the maxilla and mandible grew forward, but no significant differences emerged between the groups. Conclusions: Results suggest that mild‐type CFM is not progressive in nature. During growth, mandibular asymmetry measured in the horizontal, vertical and sagittal planes did not increase. [ABSTRACT FROM AUTHOR]

Objectives: Odontogenic keratocysts exhibit frequent recurrence, distinctive histopathological traits, a tendency towards aggressive clinical behavior, and a potential linkage to the nevoid basal cell carcinoma syndrome. The aim of this systematic review is to compile insights concerning the control of this condition and assess the effectiveness of various treatment approaches in reducing the likelihood of recurrence. Materials and methods: The following systematic review adhered to the PRISMA guidelines. The systematic revision was registered on PROSPERO and structured around the questions related to the population, intervention, control, outcome and study design (PICOS). Results: After conducting a search on the PubMed database, we initially identified 944 records. After using end-note software to remove duplicate entries, results totally with 462 distinct records. A thorough review of the titles and abstracts of these articles led to the selection of 50 papers for in-depth examination. Ultimately, following the application of our eligibility criteria, we incorporated 11 articles into our primary outcome analysis. Conclusion: Among the studies examined, the most common location for these lesions was found to be in the area of the mandibular ramus and the posterior region of the mandible. In cases where the exact location wasn't specified, the mandible emerged as the predominant site. When we considered the characteristics of these lesions in studies that mentioned locularity, most were described as unilocular in two studies, while in two other studies, the prevalence of multilocular lesions was observed. Risk factors associated with keratocyst recurrence include younger patient age, the presence of multilocular lesions, larger lesion size, and a longer anteroposterior dimension. Certain treatment methods have demonstrated a lack of relapses. These include the use of 5-fluorouracil, marsupialization, enucleation with peripheral ostectomy or resection, enucleation and curettage, as well as resection without creating continuity defects. However, it is important to note that further research is essential. Prospective studies and randomized trials are needed to collect more comprehensive evidence regarding the effectiveness of various treatment approaches and follow-up protocols for managing odontogenic keratocysts. Clinical relevance: Odontogenic keratocysts still enter into differential diagnoses with other lesions that affect the jaw bones such as ameloblastama and other tumor forms, furthermore it is not free from recurrence, therefore the therapeutic approach to the lesion aimed at its elimination can influence both the possible recurrence and complications, knowledge of the surgical methods that offer the most predictable and clinically relevant result for the management of follow-up and recurrences. [ABSTRACT FROM AUTHOR]

Introduction: Pain management is paramount in paediatric dental care, influencing patient cooperation and future perceptions of dental treatment. The widely used Inferior Alveolar Nerve Block (IANB) anaesthesia faces challenges in children due to anatomical variations. The position of the mandibular foramen, which evolves with age, growth patterns, and facial types, necessitates customised approaches for effective paediatric pain management. Aim: To identify the position of the mandibular foramen amongst children aged 7-14 years with respect to age, gender, and facial types. Materials and Methods: In a cross-sectional study conducted in West Bengal, India, 126 children aged 7-14 were investigated from March 2021 to August 2022. The Orthopantomograms (OPG) and lateral cephalograms were assessed for the location of the mandibular foramen with respect to age, sex, and facial type in clear radiographs with normal growth. Statistical analysis encompassed descriptive statistics, Analysis of Variance (ANOVA), and multiple linear regression analysis. Results: A total of 126 x-rays were analysed across age, gender, and facial types, showing a mean age of 10.78 years. There were 52 (41.3%) males and 74 (58.7%) females. The distribution of subjects according to facial types was as follows: short (n=33, 26.2%), normal (n=19, 15.1%), and long (n=74, 58.7%). The vertical position of the mandibular foramen increased with age. No significant gender difference was observed regarding the vertical position of the mandibular foramen. However, a significant variation across facial types was observed, with individuals with normal faces exhibiting a greater vertical position. Conclusion: This study revealed that the vertical position of the mandibular foramen increases with age. There was no significant difference found between males and females in the location of the mandibular foramen; however, individuals with normal faces exhibited a greater vertical position of the same. [ABSTRACT FROM AUTHOR]

The present study tested the combination of mandibular and dental dimensions for sex determination using machine learning. Lateral cephalograms and dental casts were used to obtain mandibular and mesio-distal permanent teeth dimensions, respectively. Univariate statistics was used for variables selection for the supervised machine learning model (alpha = 0.05). The following algorithms were trained: logistic regression, gradient boosting classifier, k-nearest neighbors, support vector machine, multilayer perceptron classifier, decision tree, and random forest classifier. A threefold cross-validation approach was adopted to validate each model. The areas under the curve (AUC) were computed, and ROC curves were constructed. Three mandibular-related measurements and eight dental size-related dimensions were used to train the machine learning models using data from 108 individuals. The mandibular ramus height and the lower first molar mesio-distal size exhibited the greatest predictive capability in most of the evaluated models. The accuracy of the models varied from 0.64 to 0.74 in the cross-validation stage, and from 0.58 to 0.79 when testing the data. The logistic regression model exhibited the highest performance (AUC = 0.84). Despite the limitations of this study, the results seem to show that the integration of mandibular and dental dimensions for sex prediction would be a promising approach, emphasizing the potential of machine learning techniques as valuable tools for this purpose. [ABSTRACT FROM AUTHOR]

Objective: This study aims to compare orthopantogram and lateral cephalogram for gonial angle and mandibular linear measurements (ramus height and body length). Methods: A cross-sectional study was conducted at Islamic International Dental Hospital. A total of 195 patients, both genders, ages 16 to 35 years who were citizens of Pakistan and had clear radiographs, lateral cephalograms, and OPG available, were included. Patients with craniofacial malformations and facial asymmetry were excluded. The following variables were measured. (a) body length (Go-Me) (b) ramus height (Co-Go) and (c) gonial angle on both sides. An independent sample t-test was applied to compare mandibular measurements between two radiographs (OPG and lateral cephalograms). Results: The mean age of the participants was 24.24±5.39 years. The females were 111 (56.92%) and males were 84(43.08%). Measurements on the cephalogram and OPG on the right and left sides were almost similar. The mean value of ramus height on OPG (60.93±5.39mm) was higher than on cephalogram (58.69±6.15mm) statistically significant on the right side (p<0.001). Similar statistically significant results(p<0.001) were found for ramus height being increased in the OPG on the left side(60.92±5.39mm), and body length on both sides(109.41±6.08mm). However, the gonial angle on both radiographs and both sides was insignificant (p=0.058 for the right; p=0.062 for the left). Conclusion: For angular measures of the mandible, panoramic radiographs are equally accurate as lateral cephalograms, but physicians should use caution when assuming vertical and horizontal measurements from OPGs. [ABSTRACT FROM AUTHOR]

This article from the Romanian Journal of Oral Rehabilitation discusses the challenges of extracting impacted mandibular third molars. The researchers conducted a study to determine a reliable and user-friendly index for predicting the surgical difficulty of these extractions. They categorized patients into different age groups and measured the angle of the impacted molars with the mandibular canal. The study found a correlation between the duration of the surgical intervention and the molar angulation, but no significant correlation between extraction duration and patient age. The article emphasizes the importance of removing wisdom teeth as a preventative measure and highlights potential complications due to dentists' lack of knowledge about anatomical variations. It also provides information on different types of mandibular canals and their relationship to the inferior alveolar nerve, as well as statistics on the incidence of impacted wisdom teeth in different populations and varying rates between genders. The authors recommend further research to confirm their findings. [Extracted from the article]

Abstract Objective The aim of this study was to present an innovative surgical protocol, navigation-based endoscopic enucleation (NBEE) for the treatment of large mandibular cystic lesions involving the mandibular ramus. Methods Twelve patients who presented with a large mandibular cystic lesion involving the mandibular ramus were enrolled in this study. Preoperative planning and intraoperative navigation were performed in all 12 patients. Results All patients in this study were treated with navigation-based endoscopic enucleation successfully. The follow-up period ranged from 7 to 10 months. Bone regenerated was found in all patients postoperatively. Three patients experienced temporary mandibular nerve palsy, and all relieved within 2 months. No pathological bone fracture was found during surgery. Conclusions The use of navigation-based endoscopic enucleation (NBEE) for the treatment of large mandibular cystic lesions involving the ramus proved to be an effective method for complete and precise enucleation of the cystic lesion that also preserved the surrounding tissue.

Background: Short implants have been used in the restoration of edentulous jaws in the past several years. However, some studies have suggested that short implants are less successful than standard implants. The aim of this study is to investigate the outcome of short implants placed in the posterior maxilla or mandible following one-stage or immediate-function protocols with a follow-up of 7 years (clinically) and 5 years (radiographically). Methods: This study included 127 patients rehabilitated with 217 implants measuring 7 mm and supporting 157 fixed prostheses in the posterior segments of both jaws. Final abutments were delivered at the surgery stage and were loaded after 4 months in 116 patients (199 implants). The primary outcome measure was implant survival measured through life tables. Secondary outcome measures were marginal bone loss and the incidence of biological and mechanical complications at the patient level and implant level (evaluated through descriptive statistics). Results: Twenty-four patients (18.9%) with 45 implants (20.7%) were lost to the follow-up. In total, 32 implants failed (14.8%) in 22 patients (17.3%), resulting in a cumulative survival rate at 7 years of 81.2% for 7 mm implants in the rehabilitation of the posterior regions of the maxilla and mandible. The average (standard deviation) marginal bone loss was 1.47 mm (0.99 mm) at 5 years. The incidence rate of biological complications was 12.6% and 10.6% at the patient and implant levels, respectively. The incidence rate of mechanical complications was 21.3% for patients and 16.1% for implants. A higher failure rate was registered in smokers and in implant arrangements with a sequence of three fixtures in proximity. Conclusions: Within the limitations of this study, it can be concluded that the placement of 7 mm long implants for the partial implant-supported rehabilitation of atrophic posterior jaws is possible in the long term, judging by the survival rate and stable average marginal bone loss. Nevertheless, strict case selection should be performed, especially in smokers and with implant arrangements that provide a minimum of one unit in inter-implant distance. [ABSTRACT FROM AUTHOR]

We have described here proboscideans fossil remnants which belong to six species: Prodeinotherium pentapotamiae, Gomphotherium browni, Choerolophodon corrugatus, Protanancus chinjiensis, and Elephas planifrons. The described specimens are collected from six different localities of the Siwaliks. These localities are Bhilomar, Chinji type section, Lawa, Dhok Bun Ameer Khatoon (Chinji Formation), Ochri (Dhok Pathan Formation) and Rathian (Pinjor Formation), belongs to the Lower to Upper Siwaliks, district Chakwal and Jhelum, Punjab, Pakistan. The specimens were collected from these localities after extensive fieldwork from 2015 to 2020, which confirms the presence of large mammalian fauna during the Middle Miocene to Late Pleistocene. Prodeinotherium pentapotamiae is rare taxa in the Middle Siwaliks of Pakistan, first time discovered from new fossil section Satroma wali dhal in the vicinity of the Dhok Bun Ameer Khatoon locality. Bhilomar is a less explored fossil locality belongs to the Chinji Formation, Gomphotherium browni and Choerolophodon corrugatus is reported from the Chinji type section. A beautiful juvenile mandibular ramus of Protanancus chinjiensis has been recovered first time from Lawa and Elephas planifrons were recovered from Rathian which belongs to Pinjor Formation dated as Plio-Pleistocene age of Upper subgroup of Siwaliks. Based on palaeoenvironment and stratigraphy the age of these localities is suggested as Miocene to Pleistocene. The recovered proboscideans fossil fauna indicates about the climatic changes and confirms that more seasonal extensive grasslands and savannah like ecosystem were present at that time. [ABSTRACT FROM AUTHOR]

In studies of mammalian mastication, a possible relationship has been proposed between bilateral recruitment of jaw adductor muscle force during unilateral chewing and the degree of fusion of the mandibular symphysis. Specifically, species that have unfused, mobile mandibular symphyses tend to utilize lower levels of jaw adductor force on the balancing (nonchewing) than the working (chewing) side of the head, when compared to related species with fused symphyses. Here, we compare jaw adductor recruitment levels in two species of musteloid carnivoran: the carnivorous ferret (unfused symphysis), and the frugivorous kinkajou (fused symphysis). During forceful chewing, we observe that ferrets recruit far more working‐side muscle force than kinkajous, regardless of food toughness and that high working‐to‐balancing side ratios are the result of increased working‐side force, often coupled with reduced balancing‐side force. We propose that in carnivorans, high working‐to‐balancing side force ratios coupled with an unfused mandibular symphysis are necessary to rotate the hemimandible for precise unilateral occlusion of the carnassial teeth and to sustain laterally oriented force on the jaw to engage the carnassial teeth during shearing of tough foods. In contrast, the kinkajou's flattened cheekteeth permit less precise occlusion and require medially‐oriented forces for grinding, thus, a fused symphysis is mechanically beneficial. Research Highlights: Ferrets' (unfused mandibular symphyses) use of asymmetrical jaw muscle activity may optimi forces for carnassial shearing. Kinkajous' more nearly equal force may be facilitated by their fused symphysis and flat cheek teeth. [ABSTRACT FROM AUTHOR]

Objectives Automating the digital workflow for diagnosing impacted canines using panoramic radiographs (PRs) is challenging. This study explored feature extraction, automated cropping, and classification of impacted and nonimpacted canines as a first step. Methods A convolutional neural network with SqueezeNet architecture was first trained to classify two groups of PRs (91with and 91without impacted canines) on the MATLAB programming platform. Based on results, the need to crop the PRs was realized. Next, artificial intelligence (AI) detectors were trained to identify specific landmarks (maxillary central incisors, lateral incisors, canines, bicuspids, nasal area, and the mandibular ramus) on the PRs. Landmarks were then explored to guide cropping of the PRs. Finally, improvements in classification of automatically cropped PRs were studied. Results Without cropping, the area under the curve (AUC) of the receiver operating characteristic (ROC) curve for classifying impacted and nonimpacted canine was 84%. Landmark training showed that detectors could correctly identify upper central incisors and the ramus in ∼98% of PRs. The combined use of the mandibular ramus and maxillary central incisors as guides for cropping yielded the best results (∼10% incorrect cropping). When automatically cropped PRs were used, the AUC-ROC improved to 96%. Conclusions AI algorithms can be automated to preprocess PRs and improve the identification of impacted canines. [ABSTRACT FROM AUTHOR]

Background: Real-time magnetic resonance imaging (rtMRI) is essential for diagnosing and comprehending temporomandibular joint (TMJ) movements. Current methods for tracking and analysis require manual landmark placement on each acquisition frame. Therefore, our study aimed to assess the inter- and intra-rater reliability of placing cephalometric landmarks in frames from a dynamic real-time TMJ MRI. Material and methods: Four real-time MRIs of the right TMJ were taken during mandibular movement at ten frames per second. Seven dentists identified ten landmarks on two frames (intercuspal position—ICP—and maximum mouth opening—MMO) twice at a two-week interval, yielding 112 tracings. Six typical cephalometric measurements (angles and distances) were derived from these landmarks. The reliabilities of landmarks and measurements were evaluated using distance-based (dbICC), linear mixed effect model intraclass correlation (lmeICC), and standard ICC. Results: The average inter-rater reliability for the landmarks stood at 0.92 (dbICC) and 0.93 (lmeICC). The intra-rater reliability scores were 0.97 and 0.98. Over 80% of the landmarks showed an ICC greater than 0.98 (inter-rater) and over 0.99 (intra-rater). The lowest landmark ICC was observed for the orbitale and the oblique ridge of the mandibular ramus. However, the cephalometric angle and distance measurements derived from these landmarks showed only moderate to good reliability, whereas the reliability in the frames with ICP was better than those with MMO. Measurements performed in the ICP frame were more reliable than measurements in the MMO frame. Conclusion: While dentists reliably localize isolated landmarks in real-time MRIs, the cephalometric measurements derived from them remain inconsistent. The better results in ICP than MMO are probably due to a more familiar jaw position. The higher error rate of the TMJ measurements in MMO could be associated with a lack of training in real-time MRI analysis in dentistry. [ABSTRACT FROM AUTHOR]

Aim: The aim of this study was to evaluate the effect of local betamethasone injection into the pterygomandibular space on postoperative neurosensory deficits. Materials and methods: A prospective controlled clinical study was conducted on 16 patients (6 male, 10 female; mean age, 24.95 ± 9.22 years) who underwent bilateral sagittal ramus osteotomy for mandibular discrepancies. One side of each patient's mandible was randomly selected as the control side, and the opposite side as the experimental side. On the experimental side, a solution of betamethasone (6 mg/1 ml) was injected into the pterygomandibular space after the completion of wound closure. Neurosensory tests, including light touch, two-point discrimination, direction of movement, thermal sensitivity, and pin-prick discrimination, were performed. The follow-up period ranged between 6 and 12 months, according to the particular sensory test. The Fisher exact test was used to analyse the data. Results: The light touch sensation was abnormal in 75% of the control side and 31% of the study side, with the difference being significant (p = 0.03). However, at 6 months, all the study cases regained touch sensation, compared to 69% of the control side. No significant difference in direction movement discrimination was seen; however, at 3 months, the study side showed significantly less direction sensation (19%) compared to the control side (56%) (p = 0.02). There was no significant difference in the two-point discrimination; however, at 3 months, the study side had a significantly less abnormal two-point sensation (13%) than the control side (56%) (p = 0.02). In addition, no significant difference was noted in thermal sensitivity or pin-prick sensation. Conclusion: Betamethasone injection into the pterygomandibular space reduces neurosensory disturbances after bilateral sagittal split ramus osteotomies nd leads to faster recovery of sensations. [ABSTRACT FROM AUTHOR]

The aim of this study was to introduce a novel intraoral technique for performing mandibular nerve blocks in dromedary camels (Camelus dromedarius). In this study, 18 adult camel skulls of varying ages and breeds were examined to determine the position of the mandibular foramen. Using a Vernier caliper, three dimensions in millimeters were measured: (1) the distance between the mandibular foramen (MF) and the caudal edge of the third molar tooth at the occlusal surface level, (2) the distance between the MF and the rostral edge border of the mandible's ramus (RER) at the occlusal surface level, and (3) the distance between the MF and the ventral margin border of the mandible (VM). The technique was evaluated using five intact camel cadaver heads (n = 5), and a total of ten mandibular nerve blocks were described. An 18-gauge 80-mm Tuohy needle was inserted into the mouth commissure and advanced caudally while injecting a saline-methylene blue solution. The accuracy of the injection was confirmed through the infiltration of the contrast dye into the target area using computed tomography (CT) and post procedural dissection. Anatomical study of the mandibular nerve site was performed to aid the blind insertion of the needle. The findings contribute to the development of veterinary anesthesia techniques and provide anatomical considerations for clinicians performing oral surgeries in sedated camels. The results demonstrated the successful implementation of the intraoral technique, highlighting its efficacy and reliability in achieving local anesthesia for oral surgeries involving the lower jaw and teeth in sedated camels. Further research studies are needed to evaluate the long-term efficacy and safety of the technique and to compare it with existing approaches. [ABSTRACT FROM AUTHOR]

This article discusses a study on novel endoscopic surgical approaches to the parapharyngeal internal carotid artery (ppICA). The parapharyngeal space (PPS) is a challenging area to access and lesions in this area are difficult to remove completely. The study investigates two minimally invasive endoscopic approaches (preauricular and intermaxillary mandibular) compared to the traditional transcervical approach in accessing the ppICA. The results show that both the preauricular and intermaxillary mandibular approaches provide better access to the ppICA compared to the transcervical approach. The study concludes that these novel endoscopic approaches are feasible techniques for accessing and mobilizing the ppICA. [Extracted from the article]

This article explores the use of endoscopic techniques in the treatment of intracranial tumors that invade the upper parapharyngeal space (PPS). The study compares the additional upper parapharyngeal exposure achieved through biportal endoscopic endonasal transpterygoid and endoscopic transmaxillary approaches to the standard endoscopic transsphenoidal approach. The researchers used cadaveric specimens and radiological records to measure linear trajectories, areas of exposure, angles of attack, and surgical corridor volumes. The results suggest that the biportal approach may provide sufficient surgical exposure without significant additional morbidity, but further clinical investigations are needed to confirm these findings. [Extracted from the article]

This study aims to compare the effects of mandibular distraction osteogenesis (MDO) and bone grafting on the facial symmetry of children with Pruzansky-Kaban type IIB and III craniofacial microsomia (CFM). Medical records and three-dimensional computed tomography (3D-CT) data of CFM patients who had primarily undergone MDO and bone grafting were collected. A retrospective analysis of pre-and post-operative 3D imaging data was conducted to compare the improvement rate in facial symmetry between the two groups based on occlusal cant, affected/unaffected ramus height ratio and chin point deviation. The data were tested for normality using the Shapiro-Wilk test. When the data followed a normal distribution, a paired sample t -test was employed for the comparison between preoperative and postoperative data. When the data did not follow a normal distribution, the Wilcoxon signed-rank test for paired samples was used for preoperative and postoperative comparison. The study included 18 children with type IIB and III CFM, 11 in the MDO group and 7 in the bone grafting group. In the MDO group, postoperative Gn-FH and Gn-Cor distances increased significantly, whereas the postoperative Gn-Mid distance decreased significantly. Occlusal cant decreased significantly and ramus height affected/unaffected ratio increased significantly after MDO. In the bone graft group, there was no statistically significant difference in the postoperative ratios of chin deviation, occlusal cant, and ramus height affected/unaffected compared to the preoperative values. Compared to bone grafting, MDO can significantly enhance ramus height ratio, level occlusal plane, and centralize the chin point among patients with CFM. Furthermore, MDO achieves superior enhancements in facial symmetry. [ABSTRACT FROM AUTHOR]

Objective: The purpose of this study is to investigate the type of ridge (degree of angulation of the lingual concavity) and the buccolingual dimensions in the area of the first and second molars in both genders of different ages and how this will affect implant placement in the posterior mandible. Materials and Methods: This retrospective cross‐sectional study comprised cone beam computed tomography images of 150 dental patients (75 males and 71 aged ≥30). The following were measured/reported: type (morphology) of the ridge (convex [C], parallel [P], or undercut [U]), buccolingual width at the base and the crest of the ridge, and ridge height. The concavity angle, depth, and length of the U‐shaped ridge were measured too. Results: The prevalence of type U ridge ranged from 32.7% in the first molar region to 62.7% in the second molar region. Almost all measurements and ridge type distributions were comparable amongst the age groups (p >.05). Very few significant differences were found when comparing #36 versus #37 and #46 versus #47 teeth, with no differences in the distribution of the ridge types (p >.05). Quite the inverse, all measurements were statistically different when comparing #36 versus #37 and #46 versus #47 teeth, and type U ridge was more frequent in second molar compared to the first molar regions, respectively (p <.05). Many measurements were statistically higher in females; the inverse was true for a few measurements (p <.05). Type U ridge in #36 and #37 was found more frequently among males (p <.001). In contrast, the ridge types in #37 and #47 were not statistically different gender‐wise. Conclusions: The U type of ridge was more prevalent in the investigated population, encountered more frequently in the second molars generally and in the first molars of males than females. Most posterior mandibular measurements are similar age‐ and side‐wise but seem different gender‐ and tooth‐wise. [ABSTRACT FROM AUTHOR]

Objective: The aim of this study was to present an innovative surgical protocol, navigation-based endoscopic enucleation (NBEE) for the treatment of large mandibular cystic lesions involving the mandibular ramus. Methods: Twelve patients who presented with a large mandibular cystic lesion involving the mandibular ramus were enrolled in this study. Preoperative planning and intraoperative navigation were performed in all 12 patients. Results: All patients in this study were treated with navigation-based endoscopic enucleation successfully. The follow-up period ranged from 7 to 10 months. Bone regenerated was found in all patients postoperatively. Three patients experienced temporary mandibular nerve palsy, and all relieved within 2 months. No pathological bone fracture was found during surgery. Conclusions: The use of navigation-based endoscopic enucleation (NBEE) for the treatment of large mandibular cystic lesions involving the ramus proved to be an effective method for complete and precise enucleation of the cystic lesion that also preserved the surrounding tissue. [ABSTRACT FROM AUTHOR]

Background: Mandibular distraction osteogenesis (MDO) is a major part of the treatment for hemifacial microsomia patients. Due to the narrow surgical field of the intraoral approach, osteotomy accuracy is highly dependent on the surgeons' experience. Electromagnetic (EM) tracking systems can achieve satisfying accuracy to provide helpful real-time surgical navigation. Our research team developed an EM navigation system based on artificial intelligence, which has been justified in improving the accuracy of osteotomy in the MDO in animal experiments. This study aims to clarify the effect of the EM navigation system in improving the MDO accuracy for hemifacial microsomia patients. Methods: This study is designed as a single-centered and randomized controlled trial. Altogether, 22 hemifacial microsomia patients are randomly assigned to the experiment and control groups. All patients receive three-dimensional CT scans and preoperative surgical plans. The EM navigation system will be set up for those in the experiment group, and the control group will undergo traditional surgery. The primary outcome is the surgical precision by comparing the osteotomy position of pre- and postoperative CT scan images through the Geomagic Control software. The secondary outcomes include mandibular symmetry (occlusal plane deviation angle, mandibular ramus height, and body length), pain scale, and complications. Other indications, such as the adverse events of the system and the satisfactory score from patients and their families, will be recorded. Discussion: This small sample randomized controlled trial intends to explore the application of an EM navigation system in MDO for patients, which has been adopted in other surgeries such as orthognathic procedures. Because of the delicate structures of children and the narrow surgical view, accurate osteotomy and protection of nearby tissue from injury are essential for successful treatment. The EM navigation system based on artificial intelligence adopted in this trial is hypothesized to provide precise real-time navigation for surgeons and optimally improve patient outcomes, including function and aesthetic results. The results of this trial will extend the application of new navigation technology in pediatric plastic surgery. Trial registration: Chinese Clinical Trial Registry ChiCTR2200061565. Registered on 29 June 2022. [ABSTRACT FROM AUTHOR]

This study measured and analyzed chronological changes in temporomandibular joint space volume by compartment following transoral vertical ramus osteotomy (TOVRO) using reconstructed 3-dimensional (3D) images of patients with mandibular prognathism. It included 70 joints of 35 patients who underwent TOVRO between January 2018 and December 2021. Computed tomography (CT) or cone-beam CT (CBCT) was performed before surgery (T0) and at 3 days (T1), 6 months (T2), and 12 months postoperatively (T3). These scans were then analyzed using 3D software. The volumes of the overall (Vjs), anterior (Vajs), posterior (Vpjs), medial (Vmjs), and lateral (Vljs) joint spaces were calculated at each time point. A linear mixed model and repeated-measures covariance pattern with unstructured covariance were used to evaluate significant changes in joint space volume over time. Vjs significantly increased to 134.54 ± 34.28 mm3 at T3 compared to T0 (p < 0.001). Vpjas and Vljs increased by 130.72 ± 10.07 mm3 and 109.98 ± 7.52 mm3 at T3 compared to T0, respectively (p < 0.001). However, no significant difference was observed between T0 and T2 in Vajs and Vmjs (p = 0.9999). The observed volume increases in Vpjs and Vljs appeared to contribute to the overall Vjs increase. [ABSTRACT FROM AUTHOR]

Background: Our study aimed to use three-dimensional (3D) spatial morphological measurement methods to compare the influence of Twin-Block and clear functional aligners on the temporomandibular joint (TMJ) of adolescent Class II division 1 malocclusion mandibular retraction patients. We also aimed to explore the similarities and differences in the effects on the TMJ upon using Twin-Block and clear functional aligner. Methods: Cone-beam computed tomography (CBCT) data of 49 patients with Class II division 1 malocclusion (Twin-Block group: 24; clear functional aligner group: 25) were collected before and after functional orthodontic treatment, and a 3D model of the TMJ was reconstructed using MIMICS 21.0 software. Eighteen measurement parameters, including the anterior, superior, and posterior joint spaces, were measured and compared using the 3D model. Results: After the two groups underwent functional appliance treatment, the height, volume, and surface area of the condyle, length of the mandibular ramus and mandibular length increased; The retro-displaced condyle moved to the middle position of the articular fossa, while the rest of the condylar position did not change significantly. Remodeling of the articular fossa after treatment was not evident. The superior joint space of the clear functional aligner group increased, but there was no significant change after Twin-Block appliances treatment. Conclusions: Both appliances promote condylar growth and sagittal and vertical development of the mandible in adolescent Class II division 1 malocclusion mandibular retraction patients. The length of the mandibular ramus showed a more significant increase following treatment with the Twin-Block appliances than with clear function aligners. [ABSTRACT FROM AUTHOR]

The aim of this study is to determine whether or not the breed and sex factors have an effect on the shape in the mandibles of Hamdani and Awassi sheep. A total of 31 mandibles were used. The samples were analyzed via geometric morphometric methods by using semilandmark. In the study, it was determined that the first principal component accounted for 36.52% of the total shape difference. According to principal component analysis, samples were clustered significantly in terms of breed; whereas, they were not clustered in terms of sex. In terms of the first principal component, the places where the shape differences were concentrated were the attachment sites of teeth to the mandible, between the second molar and ramus mandibulae, the processus coronoideus and the angulus mandibulae. The Mandibulae of Hamdani sheep had a higher body than the mandible of Awassi sheep. The mandibulae of male sheep was more voluminous than the mandible of female sheep, especially in the body area. Consequently, it is thought that the data obtained as a result of the study would serve as a reference for the ruminant mandible remains obtained from archaeological excavations. [ABSTRACT FROM AUTHOR]

Background: Mental foramen is a small foramen situated in anterolateral aspect of the body of the mandible. Normally, mental foramen is located below the interval between the premolars. It transmits mental nerve, artery and vein. Mental nerve is a branch of inferior alveolar nerve which supplies sensation to lower lip and the labial mucosa and lower canines and premolars. The most useful injection for anaesthetising the mandibular teeth is the inferior alveolar nerve block. Any foramen in addition to mental foramen in the body of the mandible is known as accessory mental foramen. Accessory mental foramen transmits the accessory branch of mental nerve. Materials and methods: The mandibles which were used for our study were procured from the Department of Anatomy, Siddhartha Medical College (Govt), Vijayawada over a period of 6 years. About 70 adult dry South Indian mandibles, irrespective of age and sex, with either all the teeth intact or with preserved alveolar margins, were used for our study. The bones with gross pathological deformities were excluded from our study. The number, shape and the orientation of the MF were determined by a visual examination. The shape of mental foramen in dry human adults was analyzed by visual examination of the both sides of the mandible. Result: The present study showed that the position of mental foramen from symphysis menti and posterior border of ramus of mandible was more on right side than left side and found to be insignificant while position of mental foramen from inferior border of body of mandible was more on left side than right side and found to be insignificant for right side while significant for left side. The shape of mental foramen on right side was found to be Oval shape - 65.7% and round shape - 34.3% while on left side Oval shape-71.4% and round shape - 28.6%. Conclusion: Hence, mental foramen plays a pivotal role in performing major facial surgeries and is an important landmark for several facial procedures performed. [ABSTRACT FROM AUTHOR]

As a member of Aceratheriinae, the genus Plesiaceratherium in Europe is widely distributed and highly diverse. However, only one species of Plesiaceratherium (i.e., P. gracile) exists in China with a discontinuous distribution range. Recently, we have discovered new materials of Plesiaceratherium in the lower layers of the Zhang'enbao Formation exposed in Miaoerling in Tongxin County, China. The new materials are well-preserved and can be separated from other Plesiaceratherium species by the following combination of features: the long and generally flat skull, with closed frontoparietal crests; the deep nasal notch at the level of P4; the high supraorbital margin, with its anterior margin at the level of the M1/M2 boundary; the mediumsized upper I1, with an oval abraded surface; the semi-molarized upper premolars with the protocone and hypocone joined by a lingual bridge; the strong constrictions of protocone on the upper molars; the absent buccal cingulum on upper cheek teeth; the cheek teeth are covered by cement on the buccal walls; the convex base of mandibular corpus; the inclined backward ramus; and the mandibular foramen above the teeth neck. Based on the combination of characteristics and phylogenetic analysis, we herein establish the new species as Plesiaceratherium tongxinense sp. nov. living in the late Early Miocene. Phylogenetic analysis reveals that P. tongxinense is in the basal position of the genus Plesiaceratherium, providing more detailed morphological characteristics of the plesiaceratheres. [ABSTRACT FROM AUTHOR]

The mandibular condylar cartilage (MCC) is an essential component of the temporomandibular joint, which orchestrates the vertical growth of the mandibular ramus through endochondral ossification with distinctive modes of cell differentiation. Parathyroid hormone–related protein (PTHrP) is a master regulator of chondrogenesis; in the long bone epiphyseal growth plate, PTHrP expressed by resting zone chondrocytes promotes chondrocyte proliferation in the adjacent layer. However, how PTHrP regulates chondrogenesis in the MCC remains largely unclear. In this study, we used a Pthrp-mCherry knock-in reporter strain to map the localization of PTHrP+ cells in the MCC and define the function of PTHrP in the growing mandibular condyle. In the postnatal MCC of Pthrp mCherry/+ mice, PTHrP-mCherry was specifically expressed by cells in the superficial layer immediately adjacent to RUNX2-expressing cells in the polymorphic layer. PTHrP ligands diffused across the polymorphic and chondrocyte layers where its cognate receptor PTH1R was abundantly expressed. We further analyzed the mandibular condyle of Pthrp mCherry/mCherry mice lacking functional PTHrP protein (PTHrP-KO). At embryonic day (E) 18.5, the condylar process and MCC were significantly truncated in the PTHrP-KO mandible, which was associated with a significant reduction in cell proliferation across the polymorphic layer and a loss of SOX9+ cells in the chondrocyte layers. The PTHrP-KO MCC showed a transient increase in the number of Col10a1+ hypertrophic chondrocytes at E15.5, followed by a significant loss of these cells at E18.5, indicating that superficial layer–derived PTHrP prevents premature chondrocyte exhaustion in the MCC. The expression of Runx2, but not Sp7, was significantly reduced in the polymorphic layer of the PTHrP-KO MCC. Therefore, PTHrP released from cells in the superficial layer directly acts on cells in the polymorphic layer to promote proliferation of chondrocyte precursor cells and prevent their premature differentiation by maintaining Runx2 expression, revealing a unique PTHrP gradient-directed mechanism that regulates MCC chondrogenesis. [ABSTRACT FROM AUTHOR]

INTRODUCTION: In the context of forensic identification, sex determination is the first important step, and the mandible is of particular interest because it shows clear signs of dimorphism. Objectives: The purpose of this investigation was sex classification through the application of several craniomandibular metric variables in a Portuguese adult population. MATERIAL AND METHODS: 206 orthopantomographic images (116 females and 90 males) were selected from Portuguese adults aged between 25 and 79 years. From each image, 14 linear variables were measured using ImageJ® software. IBM SPSS® software version 27.0 was applied to analyze data presented as extremes, mean, standard deviation, and median. Statistical methodologies included intra-class analysis, normality test, t-test, Mann-Whitney test, logistic regression, and ROC curve to determine cut-off point and respective sensitivity and specificity of sex classification. RESULTS: Comparing the two sexes, all variables showed significant differences, except for the angular variables. Variables with the best area under ROC curve were height of the right (0.861) and left (0.850) mandibular ramus. Based on the logistic regression, the left coronoid height, right mandible body height, left mandible body height, and right mandible ramus height showed an accuracy level of 83.0%, sensitivity of 86.2%, and specificity of 78.9% in sex classification. CONCLUSIONS: The obtained results show identifiable mandibular dimorphism in the measurements of mandibular structures in orthopantomography images. These metric variables allow for the creation of discrimination models between males and females in a Portuguese adult population. [ABSTRACT FROM AUTHOR]

Multiple myeloma (MM) is a plasma cell malignancy, and its typical radiographic presentation includes punched-out radiolucency of the skull. It is a bourgeois description of myeloma and often holds good in most cases. However, the diagnosis can get tricky when a patient walks into the clinic with non-specific signs and symptoms. Many suspicions arise when we examine a well-defined mandibular swelling, but the real picture is revealed with thorough screening. This article presents a rare mandibular swelling diagnosed as MM, emphasizing important differential diagnoses for maxillofacial surgeons and pathologists. [ABSTRACT FROM AUTHOR]