Mandibular Ramus Height Research Articles

Two-step cluster analysis based on three-dimensional CT measurements of craniofacial structures in severe craniofacial microsomia

BackgroundThe Pruzansky-Kaban and OMENS classifications do not provide additional details on temporomandibular joint deformities. The aim of this study was to classify and quantitatively delineate severe forms of craniofacial microsomia based on three-dimensional maxillofacial measurements, focusing on deformities in the zygomatic, temporal, and mandibular bones. MethodsMaxillofacial computed tomography(CT) scans of children with severe types of CFM from 2010 to 2020 were collected. Three-dimensional measurements of zygomatic arch length, height of mandibular ramus, height of maxilla, and occlusal cant were performed. Two-step cluster analysis was conducted based on zygomatic arch continuity, occlusal cant, the ratio of affected side to unaffected side(A/U ratio) for zygomatic arch length, mandibular ramus height, and maxillary height. ResultsFifty patients (32 male, 18 female) were included in the study. They were classified into 2 clusters through cluster analysis. Cluster 1 comprised subjects (44% of patients) with continuous zygomatic arches. Cluster 2 comprised subjects (39%) with discontinuous zygomatic arches. The zygomatic arch A/U ratio in Cluster 1 was greater than that in Cluster 2, with statistical significance observed. Additionally, the maxilla height A/U ratio in Cluster 1 was lower than in Cluster 2, also with statistical significance. There was no statistically significant difference observed in the ramus height A/U ratio and occlusal cant between Cluster 1 and Cluster 2. ConclusionsBased on craniofacial measurements, severe CFM can be categorized into two types: continuous zygomatic arch and discontinuous zygomatic arch. This cluster analysis complemented the OMENS classification and could assist in the selection and design of prosthetic joints for patients with CFM.

Personalized Temporomandibular Joint Total Alloplastic Replacement as a Solution to Help Patients with Non-Osteosynthesizable Comminuted Mandibular Head Fractures.

Background: Treatment methods for mandibular head fractures are controversial, although effective techniques for open reduction and rigid fixation (ORIF) have been known since the late 1990s. Notably, some forms of posttraumatic comminution of the mandibular head can be reduced or fixed. Methods: This study presents a personalized treatment to cure patients with nonreduced comminuted fractures of the mandibular head: total temporomandibular joint alloplastic replacement (18 patients). The reference group included patients who underwent ORIF (11 patients). Results: Personalized alloplastic joint replacements resulted in a more stable mandibular ramus after three months compared with ORIF. Conclusions: The authors recommend not performing osteosynthesis when the height of the mandibular ramus cannot be stably restored or when periosteal elevation from most of the mandibular head is necessary for ORIF. Personalized TMJ replacement should be considered in such patients. Personalized medicine allows patients to maintain a normal mandibular ramus height for a long period of time.

Does mandible ramus height asymmetry affect postoperative skeletal stability in orthognathic surgery patients?

BackgroundRelapses 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.MethodsThis 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.ResultsA 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).ConclusionAfter 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.

Gonial angle and mandibular ramus height in Surabaya population: comparison and correlation analysis in panoramic radiograph

Gonial angle and mandibular ramus height in Surabaya population: comparison and correlation analysis in panoramic radiograph

Hard and Soft Tissue Facial Landmarks for Mandibular Angle Reduction: A Clinical Study.

Square faces, which are influenced by genetic factors and structural features, are considered undesirable among the Asian population. Surgical interventions, such as mandibular angle reduction, aim to alter these characteristics, though complications may arise. We aimed to investigate the morphology of the mandibular angle and masseter muscle thickness using computed tomography (CT) and to analyze hard and soft tissue correlations to enhance surgical outcomes for patients with square faces. This retrospective clinical study included 100 Taiwanese patients aged 18-50 years. CT was used to analyze key clinical parameters, including bilateral mandibular width, mandibular divergence angle, ramus height, distance from the mandibular angle to the inferior alveolar nerve (IAN), and the thickness of the masseter muscle. Significant correlations were noted between the patients' physical height and weight, mandibular width, ramus height, masseter thickness, and distance from the angle to the IAN. Males exhibited a significantly longer and thicker ramus height (66.48 ± 4.28 mm), greater masseter thickness (15.46 ± 2.35 mm), and greater safety range for mandibular angle reduction surgery (18.35 ± 3.19 mm) (p < 0.00008). Significant correlations were observed among all parameters, except between mandibular width and gonial angle and the distance from the angle to the IAN and between mandibular divergence and masseter muscle thickness (p > 0.1). Our study highlighted the complex interplay among factors that contribute to square facial morphology. Careful preoperative assessments and customized surgical planning are essential for addressing this multifaceted clinical challenge.

Effect of mandibular third molar tooth germ extraction on mandibular development: a retrospective study

Objective: To investigatethe effect of extraction of mandibular third molar (M3) tooth germon the development of the mandible in orthodontic patients, with a view to providing a reference for clinical M3 tooth germ extraction. Methods: One hundred and twenty-nine Angel class Ⅰ patients aged 10-16 years who attended the Department of Orthodontics Division 1, School & Hospital of Stomatology, Wuhan University from 1 January 2013 to 30 December 2021 and fulfilled the criteria for nativity were included. Those who had their M3 extracted in the Department of Oral and Maxillofacial Surgery were included in the study group, with a total of 66 cases; and those who did not have their M3 extracted were included in the control group, with a total of 63 cases. The average annual growth was calculated by tracing point measurements on cephalometric films before and after orthodontic treatment according to the Jarabak and McNamara methods, with measurements of the mandibular ramus height (Ar-Go'), mandibular body length (Go'-Me), and overall mandibular length (Co-Gn) values, respectively. The average annual growth of Ar-Go', Go'-Me, and Co-Gn were compared between the two groups for the overall sample of patients, patients of the same sex (male/female), patients of the same age group (A, B, and C), and patients of the same cervical vertebral maturation stage (stages Ⅱ, Ⅲ, and Ⅳ), respectively, to see if there was any difference in the average annual growth of Ar-Go', Go'-Me, and Co-Gn. Results: There was no statistically significant difference in the average annual growth of Ar-Go', Go'-Me, and Co-Gn between the study group [0.88 (0.40, 1.80), 0.67 (0.15, 1.18), and 0.86 (0.40, 1.90) mm, respectively] and the control group [1.08 (0.45, 1.60), 0.53 (0.25, 1.13), and 1.20 (0.46, 2.28) mm, respectively] (P>0.05). In addition, there was no significant difference in the average annual growth in the Ar-Go', Go'-Me, and Co-Gn between the groups for patients of the same sex group (male/female), patients of the same age group (A, B, and C), and patients of the same cervical vertebral maturation stage group (stages Ⅱ, Ⅲ, and Ⅳ) (P>0.05). Conclusions: Extraction of the mandibular third molar tooth germ has no significant effect on the development of the mandible in Angle class Ⅰ orthodontic patients.

Evaluation of post-activation mandibular remodelling in children with craniofacial microsomia treated with distraction osteogenesis.

Patients with type IIA craniofacial microsomia (CFM) may benefit from mandibular distraction osteogenesis (MDO) treatment during childhood; however, remodelling of the mandible during the consolidation phase, which may affect the short-term outcomes of MDO, has not yet been quantitatively analysed using computed tomography. Therefore, we aimed to investigate bone remodelling of the mandible in children with type IIA CFM treated with MDO before distractor removal and the factors that influence ramus vertical elongation efficiency. Twenty-three children with unilateral CFM were studied between 2020 and 2024. Longitudinal computed tomography data (preoperative, end of active phase and at pre-distractor removal) were analysed. Condyle positions and the mandibular cant were analysed using a paired-sample t test. The relapse rates of vertical lengthening and mandibular cant were calculated. The correlation between distraction efficiency and preoperative craniofacial morphology was analysed. The condyle on the affected side moved upwards and backwards by 28.84 ± 4.08 and 2.85 ± 4.33 mm, respectively during the active phase but lost 7.66 ± 2.64 mm of vertical extension during the consolidation phase. The relapse rates for vertical extension of the condyle and occlusal plane were 27% and 35%, respectively. The ratio of mandibular ramus height was positively related to EV. In children with CFM, attention should be paid to vertical elongation instability and relapse of mandibular inclination during consolidation. Severe mandibular ramus hypoplasia is a preoperative risk factor for vertical skeletal relapse during consolidation. Further efforts are required to reduce the stress that leads to relapse.

Hanna's Modified Sagittal Split Osteotomy (HSSO): An Alternative to Inverted L Osteotomy-Merging Function and Aesthetics for Enhanced Stability, Attractiveness, and Nerve Protection.

Background: The current high standards in orthognathic surgery demand surgical solutions that are both ⁠ functionally ⁠ effective and aesthetically pleasing. Our approach offers one for enhanced stability, attractiveness, and nerve protection ⁠ with improved accessibility ⁠ in the majority of orthognathic scenarios ⁠ compared to an inverted L osteotomy. Methods: A case series is presented to illustrate the application and outcomes of HSSO, an optimised approach that combines the advantages of a transoral inverted L osteotomy with specific enhancements and increased versatility, ⁠ with accessibility and exposure similar to a BSSO. Results: HSSO as a completely transoral technique, demonstrate the ability to perform significant counterclockwise rotations of the mandible, eliminating the need for trocars or skin incisions. We experinced high postoperative stability when HSSO was performed in conjunction with a three-piece LeFort 1 osteotomy on a dynamic opposing arch. In comparison to an inverted L approach, we postulated that HSSO offers advantages in stability, due to the increased segmental overlap of the proximal and distal segments of the mandible. This approach is designed to enhance the safety of the inferior alveolar nerve compared to traditional sagittal split methods. Furthermore, HSSO represents an alternative to total joint replacement in select cases of idiopathic condylar resorption and is effective for correcting mandibular asymmetries while maintaining jawline aesthetics. This is achieved through the manipulation of the mandibular angle, ramus height, and inferior border without creating a step deformity in the soft tissue. Conclusions: The outcomes of HSSO highlight its capacity to deliver predictable, functional, and aesthetically pleasing results, offering a viable alternative to more traditional orthognathic techniques.

Mandibular and dental measurements for sex determination using machine learning

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.

Application of panoramic radiographs in the diagnosis of temporomandibular disorders.

To evaluate the feasibility of temporomandibular disorder (TMD) diagnosis with panoramic radiography, and provide standardized data for artificial intelligence-assisted diagnosis by measuring the differences in the condylar and mandibular ramus heights. A total of 500 panoramic radiographs (219 male and 281 female participants) of healthy individuals were examined. The panoramic machine compatible measurement software, SCANORA 5.2.6, was used to measure the bilateral condylar height and mandibular ramus height, and SPSS 27.0 was used to calculate the left- and right-side differences in condylar height and mandibular ramus height of healthy individuals. Magnetic resonance images of the temporomandibular joint region obtained from 46 outpatients in the Stomatology Department were selected along with their corresponding panoramic radiographs. The left- and right-sided differences were measured and compared with the magnetic resonance imaging results. The measurement data are expressed as mean ± standard deviation (mm). t Tests were used to analyze data from healthy male and healthy female groups. The findings revealed that while there was no significant difference (P > .05) in the height of the condyle between men and women, there was a significant difference (P < .05) in the height of the mandibular ramus. In healthy population, the difference in height between the left and right condyle was 1.09 ± 0.99 mm. The difference in height of mandibular ramus in men was 1.26 ± 0.85 mm and that in women was 1.19 ± 0.87 mm. For the diagnosis of TMD, the sensitivity of panoramic radiographs was 94.74% (36/38), specificity was 75.00% (6/8), and diagnostic accuracy was 91.30% (42/46). The height of the right and left lateral condyles was not identical in healthy individuals, resulting in a discernible height discrepancy. In addition, the height of the mandibular ramus varied. By considering the left-right lateral height differences identified in this study along with clinical examination, it is possible to employ this metric as a preliminary screening tool for patients with TMD. Further, the use of panoramic radiographs for initial TMD screening is both viable and significant.

3D analysis of condylar and mandibular remodeling one year after intra-oral ramus vertical lengthening osteotomy.

Among the existing techniques for the correction of mandibular posterior vertical insufficiency (PVI), the intra-oral ramus vertical lengthening osteotomy (IORVLO) can be proposed as it allows simultaneous correction of mandibular height and retrusion. This study assessed the 3D morpho-anatomical changes of the ramus-condyle unit and occlusal stability after IORVLO. This retrospective analysis compared immediate and 1-year post-operative 3D CBCT reconstructions. The analysis focused on the condylar height (primary endpoint) and on the changes in condylar (condylar diameter, condylar axis angle) and mandibular (ramus height, Frankfort-mandibular plane angle, gonion position, intergonial distance, angular remodeling) parameters. Additionally, this analysis investigated the maxillary markers and occlusal stability. On the 38 condyles studied in 21 included patients (mean age 23.7 ± 3.9years), a condylar height (CH) loss of 0.66mm (p < 0,03) was observed, with no correlation with the degree of ramus lengthening (mean 13.3 ± 0.76mm). Only one patient presented an occlusal relapse of Class II, but a 3.4mm (28%) condylar diameter loss and a 33% condylar volume reduction with loss of 1mm and 3.4mm in CH and condyle diameter, respectively. A mean 3.56mm (p < 0.001) decrease in ramus height was noted, mainly due to bone resorption in the mandibular angles. This study confirms the overall stability obtained with IORVLO for the correction of PVI. This study aims to precise indication of IORVLO, and to validate the clinical and anatomical stability of results.

Efficacy of navigation system-assisted distraction osteogenesis for hemifacial microsomia based on artificial intelligence for 3 to 18 years old: study protocol for a randomized controlled single-blind trial

BackgroundMandibular 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.MethodsThis 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.DiscussionThis 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 registrationChinese Clinical Trial Registry ChiCTR2200061565. Registered on 29 June 2022.

Insight into age-related changes of the human facial skeleton based on medieval European osteological collection

Aging changes in the facial skeleton are concentrated mostly in orbits, maxilla and mandible. The aim of this study was to analyze metric traits of the adult viscerocranium in a medieval sample from Cedynia (Poland, Central Europe) and confront the results with literature data for modern populations. It was assumed that diet-related greater biomechanical forces generated during mastication in medieval versus modern times led to slower rate of bone resorption with age. 3D models of the facial skeleton are created for 230 individuals, categorized into young, middle and old adults, and a subgroup of edentulous middle adults is distinguished. Orbits, piriform aperture, maxilla and mandible are measured using Geomagic Studio 12 and analyzed among age categories as well as dentate and edentulous subgroups. The values of the orbital and piriform aperture measurements tend to increase with age and reached statistical significance in males (right orbit height, left orbit width, piriform aperture surface area). In females, maxillary height significantly decrease at right first premolar and first molar, together with height of the right mandibular ramus. In edentulous individuals of both sexes the orbits are wider, and maxillary and mandibular heights are lower than in dentate individuals. This study reveals similar character and direction of the aging process of the facial skeleton in medieval and modern adults, however slower rate of resorptive changes is found in the former sample, which suggests, that diet-related biomechanical forces can influence intensification of the aging processes in the facial skeleton.

The importance of remodeling physiological mandibular angle: mandibular "V-line" versus long curved ostectomy.

Numerous surgical options for correcting prominent mandibular angles in East Asians have been reported. The objective of this study is to investigate the importance of remodeling physiological mandibular angle by comparing the surgical effects and complications of mandibular "V-line" ostectomy and long curved ostectomy. A retrospective study was conducted on patients who underwent either mandibular "V-line" ostectomy (Group I) or long curved ostectomy (Group II). The outcomes were evaluated using computed tomography (CT) images in combination with medical records and photographs. Data were collected preoperatively and at 6- to 12-month intervals postoperatively. Mandibular angle, posterior mandibular ramus height, radian of the ostectomy line, mandibular symmetry as well as patients' complications were investigated. FACE-Q reports of facial appearance and psychosocial parameters were also compared between the two groups. All 106 patients showed improved lower facial contours. Although the postoperative mandibular angle (116.67±7.14°vs 118.31±6.80°, P=.233) and mandibular symmetry (2.36±1.21mm vs 2.56±1.19mm, P=.395) were similar in the two groups, larger postoperative posterior mandibular height and lower radian of the ostectomy line were observed in Group I (P < .001). Physiological mandibular angle was also remodeled in Group I. The gonial deficiency, more soft tissue sagging and significant lower FACE-Q scores of facial appearance were observed in Group II (P < .001). In conclusion, "V-line" ostectomy is better suited for achieving a more physiological mandibular angle with less complications compared to mandibular long curved ostectomy. When it comes to mandibular contouring, "V-line" ostectomy may be the preferred option.

Comparison of accuracy of panoramic radiograph and lateral cephalogram in determining linear mandibular measurements among orthodontic patients in tertiary dental care center of Kathmandu

Mandibular dimensions are one of the key parameters for planning the treatment by an Orthodontist. Lateral cephalograms are usually used to evaluate the skeletal relationship. However, due to the superimposition of both the sides, lateral cephalogram may not be reliable in measuring the right and left sides of the cranial landmarks. Panoramic radiography delivers a wide-ranging view of maxillofacial structures with comparatively lesser radiation exposure than other tools and superimposition of structures is less compared to lateral cephalogram image. OPG and lateral cephalograms of all the patients of age group 16-35 years attending Department of Orthodontics in Nepal Medical College from September 2022 to February 2023, having Angle’s Class I Molar relationship with minimum crowding was taken. Linear measurements (ramus height, total mandibular length and mandibular body length) were measured on OPG and Lateral cephalogram. The data was processed in SPSS version 17 for further analysis. There was no statistically significant difference in mean linear measurements between right and left sides on OPG (p-value 0.77, 0.49 and 0.59 respectively). But there was a statistically significant difference in mean linear measurements between both sides on OPG and lateral cephalograms (p-value &lt;0.001). OPG can be used reliably to measure the mandibular length and ramus height of right and left side but comparison of mandibular length and ramus height between lateral cephalogram and OPG may not be reliable.

Cone-beam computed tomography study of mandibular morphology and tooth compensation in asymmetrical patients

This study evaluated mandibular morphology and transverse dental compensation between symmetrical and asymmetrical subjects, allocated according to sagittal skeletal patterns. In addition, the hypothesis that mandibular morphology and dental compensations differed between symmetrical/asymmetrical groups and also among the different types of sagittal skeletal patterns was tested. Cone-beam computed tomography images of 96 patients were included in this study and were divided into 2 groups according to the degree of menton deviation: a symmetrical group with deviation up to 2.0 mm (n= 48; mean age, 15 ± 6 years), and an asymmetrical group with deviation from 3.5 mm (n= 48; mean age, 16 ± 8 years). The 2 groups were divided in accordance with the ANB angle: Class I, II, and III. Skeletal and dental measurements were performed. Intergroup and intragroup analyses were carried out, using a 2-way analysis of variance to assess the interaction of factors: symmetry and sagittal skeletal pattern; and the Student t test for differences between deviated (Dv) and nondeviated (NDv) sides. Symmetrical/asymmetrical groups and Class I, II, and III groups were similar in relation to demographic aspects (P= 0.412 and P= 0.357 for sex and age, respectively). Asymmetrical patients had higher values for body length and mandibular ramus and condyle height on the NDv side (P= 0.011, P= 0.024, and P= 0.001, respectively). When comparing the different skeletal patterns, patients with a Class III relationship demonstrated higher values for mandibular ramus height. Intergroup analysis showed no differences in dental parameters. In the comparison between the sides, the asymmetrical group showed a significant difference in canine inclination (P= 0.008), mandibular ramus height (P= 0.004), condyle height (P= 0.010) and gonion to midsagittal plane distance (P= 0.018). Asymmetrical subjects showed higher values for canine inclination and mandibular body, ramus and condylar height on the NDv side. The hypothesis was partially confirmed that mandibular morphology and dental compensations are different between symmetrical/asymmetrical groups and among different sagittal skeletal patterns.

Assessment of mandibular asymmetry in different skeletal malocclusions and vertical patterns in adult individuals: A cone-beam computed tomography study

The study aims to measure the mandibular condylar height (CH), ramus height (RH), total height (CH+RH), asymmetry index, and condylar volume (Cvol) in individuals with different anteroposterior and vertical skeletal discrepancies.The study sample consisted of 131 subjects (60 females and 71 males) with a mean age of 35.06 ± 12.79 years. Pre-existing CBCT images were divided into groups according to the anteroposterior and vertical skeletal discrepancies. The investigator analyzed the data using t-tests to assess the mandibular bilateral sides of the individuals and gender differences. The mean difference between groups was determined using a one-way analysis of variance (ANOVA). The Chi-square test was used to study the association between the asymmetry index and groups.Each individual's bilateral sides exhibited statistically significant differences in CH, RH, and Cvol (P = 0.033, P = 0.039, P = 0.005, respectively), but not in CH+RH (P = 0.458). There were, however, statistically significant gender differences in CH+RH (P < 0.001). Skeletal Class III and hypodivergent groups revealed the highest linear and volumetric values compared to other groups. The asymmetry index was increased in CH (P = 0.006) and Cvol (P = 0.002) in skeletal Class II subjects.Significant differences in CH, RH, and Cvol were found on the right and left sides of the same individual. This study found increased linear and volumetric values in males, skeletal Class III, and hypodivergent subjects. Class II individuals had an increased CH and Cvol asymmetry index. This study highlights in-depth knowledge of mandibular asymmetry, which is extremely important to achieve an accurate diagnosis and provide the best treatment outcome.

In utero exposure to selective serotonin re-uptake inhibitor affects murine mandibular development.

Antidepressants, specifically Selective Serotonin Re-uptake Inhibitors (SSRIs), that alter serotonin metabolism are currently the most commonly prescribed drugs for the treatment of depression. There is some evidence to suggest these drugs contribute to birth defects. As jaw development is often altered in craniofacial birth defects, the purpose of this study was to interrogate the effects of in utero SSRI exposure in a preclinical model of mandible development. Wild-type C57BL6 mice were used to produce litters that were exposed in utero to an SSRI, Citalopram (500 μg/day). Murine mandibles from P15 pups were analysed for a change in shape and composition. Analysis indicated an overall shape change with total mandibular length and ramus height being shorter in exposed pups as compared to controls. Histomorphometric analysis revealed that first molar length was longer in exposed pups while third molar length was shorter in exposed as compared to control. Histological investigation of molars and surrounding periodontium revealed no change in collagen content of the molar in exposed pups, some alteration in collagen composition in the periodontium, increased alkaline phosphatase in molars and periodontium and decreased mesenchymal cell marker presence in exposed mandibles. The results of this study reveal SSRI exposure may interrupt mandible growth as well as overall dental maturation in a model of development giving insight into the expectation that children exposed to SSRIs may require orthodontic intervention.

Comparison of ramal heights in individuals with clinically symmetrical and asymmetrical faces.

To compare the mandibular ramal height differences between clinically symmetrical and asymmetrical face individuals. The comparative cross-sectional study was conducted from May 2020 to July 2021 at the Armed Forces Institute of Dentistry, Rawalpindi, Pakistan, and comprised subjects regardless of age and gender who were divided into two equal groups. Those with a clinically symmetrical face were in Group-I, and those with a clinically asymmetrical face were in Group-II. Mandibular ramal height of both sides of all subjects was measured, and asymmetry index. Differences of both right and left ramal heights of each group were measured and compared. Data was analysed using SPSS 26. Of the 78 subjects, 40(51%) were males and 38(49%) were females. The overall mean age was 18±5.78 years, with 44(56%) aged 16-25 years, 28(36%) <15 years and 6(8%) >26 years. There was high but non-significant correlation between the right and left sides of both the groups (p>0.05). Inter-group differences were significant with respect to ramal height (p=0.000), whereas difference in terms of asymmetry index was not significant (p>0.05). There were significant differences in the mean ramal height between clinically symmetrical and asymmetrical face individuals.

BSSRO Improves Mandibular Morphology Mainly through Correction of Body Length and Volume in Patients with Asymmetric Mandibular Prognathism.

Purpose: The purpose of this study is to analyze the change and stability of mandibular morphology in patients with asymmetric mandibular prognathism after bilateral sagittal split ramus osteotomy (BSSRO). Methods: We retrospectively analyzed fifty patients with asymmetric mandibular prognathism from the West China Hospital of Stomatology, Sichuan University, between January 2018 to March 2021. The spiral CT data before surgery, within two weeks after surgery, and at more than six months after surgery of each patient were collected. According to the deflection direction of the chin, the bilateral mandibles were defined as the long side and the short side. The morphological data of the bilateral condyle, the mandibular ramus, and the mandibular body were analyzed to determine the effect and stability of BSSRO on asymmetric mandibular prognathism. Results: It was found that the long-side mandible had greater condylar volume and diameter, mandibular ramus height and volume, and mandibular body length and volume (p < 0.05) before surgery. After surgery, the volume of the mandibular ramus increased, while the length and volume of the mandibular body decreased (p < 0.05) at the long side of the mandible; the morphological changes of the mandibular ramus and body at the short side of the mandible were not statistically significant (p > 0.05). When comparing the long and short sides of the mandible, the long side still had greater height and volume of the mandibular ramus (p < 0.01). The volume difference of the mandibular body from the two sides was corrected (p > 0.05), and the length difference of the mandibular body from the two sides was overcorrected (p < 0.05). At more than six months after surgery, the volume of the mandibular ramus and body increased, while their height decreased at the long side of the mandible (p < 0.05). For the other side, or the short side, the volume of the ramus and body increased, too. However, their height decreased (p < 0.01). Conclusion: The results of this study suggested good effect and stability of BSSRO on asymmetric mandibular prognathism, except for the correction of ramus height and volume.