Mandibular Angle Research Articles

Facial Anthropometric Analysis of Gender-Related Characteristics in Computed Tomography.

In recent years, facial feminization surgery (FFS) has gained increasing popularity because of increases in transgender individuals and the acceptance of diversity in gender identity. However, there is still a scarcity of anthropometric research to guide evidence-based practices for FFS in Taiwan. The purpose of this study was to provide a reference for surgeons to achieve optimal outcomes for patients undergoing FFS. The anthropometric analysis could help surgeons meet patients' specific requirements and improve patients' alignment with their gender identity. The study group consisted of 100 patients (50 males and 50 females) who had undergone cranial computed tomography at Chang Gung Memorial Hospital in Taiwan because of the indication of blunt injuries to the head and face with suspected skull and facial fractures. The computed tomography images were imported into the OsiriX image software to conduct an anthropometric evaluation. The parameters used in the measurements included 2 aspects: bone and soft tissue anthropometric analysis. Anthropometric data were obtained from 50 males (age 32.6 ± 11.4 years) and 50 females (age 33.7 ± 10.3 years). The results for bone measurements showed that both the forehead bossing length and nasal bone width in the male group were significantly greater. The frontal angle in both bone and soft tissue in the male group was significantly smaller. The chin height and bigonial width in both bone and soft tissue in the male group were significantly greater. Although the average gonial angle was greater in the female group, the difference was not significant. For the measurements of lip projection, the results showed that there was no significant difference. Although this group of Asian males had more acute nasolabial angles, the difference was not statistically significant. However, the average nasofrontal angle among females was significantly more obtuse than among males. The results revealed that Asian males tend to have more prominent superior orbital rims, wider nasal bones, and wider and taller mandibles compared with Asian females. Despite showing some trends, the gonial angle and lip projections did not reveal any significant differences, which is likely because of a large amount of variation.

Radiographic Estimation of Association between Condylar Morphology, Ramal Height, and Mandibular Plane Angle in Various Growth Patterns in District Solan Population in Himachal Pradesh

Introduction: In young adults, the mandibular condyle plays an essential role in the stability of long-term orthodontic and orthognathic treatments. Its morphology varies significantly between individuals and is associated with age, sex, facial type, occlusal force, functional load, malocclusion type, and right and left sides. Aim: The aim of the study was to estimate the association between morphology of condyle, ramus height, and mandibular plane (MP) angle in young adult patients with various vertical skeletal growth patterns. Materials and Methods: The present study was conducted on 90 pretreatment panoramic radiographs of subjects aged between 17 and 21 year of age; the patients were divided into three groups as hypodivergent, normodiveregent, and hyperdivergent with 30 subjects in each group on the basis of Sella-Nasion-MP angle. Various parameters were measured to record the condyle morphology, ramus height, and mandibular angle for all the groups. Results: The intergroup comparisons showed that hypodivergent group has statistically significantly greater values compared to those in the hyperdivergent group. A statistically significant difference was detected between the normodivergent and hypodivergent groups only in the condylar area measurements Conclusion: The condylar height was greater in patient with Class I malocclusion. The condylar height width and other perimeters were greater in males than females.

Cephalometric evaluation of skeletal stability and pharyngeal airway changes after mandibular setback surgery: Bioabsorbable versus titanium plate and screw fixation.

This study compared sequential changes in skeletal stability and the pharyngeal airway following mandibular setback surgery involving fixation with either a titanium or a bioabsorbable plate and screws. Twenty-eight patients with mandibular prognathism undergoing bilateral sagittal split osteotomy by titanium or bioabsorbable fixation were randomly selected in this study. Lateral cephalometric analysis was conducted preoperatively and at 1 week, 3-6 months, and 1 year postoperatively. Mandibular stability was assessed by examining horizontal (BX), vertical (BY), and angular measurements including the sella-nasion to point B angle and the mandibular plane angle (MPA). Pharyngeal airway changes were evaluated by analyzing the nasopharynx, uvula-pharynx, tongue-pharynx, and epiglottis-pharynx (EOP) distances. Mandibular and pharyngeal airway changes were examined sequentially. To evaluate postoperative changes within groups, the Wilcoxon signed-rank test was employed, while the Mann-Whitney U test was used for between-group comparisons. Immediate postoperative changes in the airway were correlated to surgical movements using the Spearman rank test. Significant changes in the MPA were observed in both the titanium and bioabsorbable groups at 3-6 months post-surgery, with significance persisting in the bioabsorbable group at 1 year postoperatively (2.29°±2.28°; P<0.05). The bioabsorbable group also exhibited significant EOP changes (-1.21±1.54 mm; P<0.05) at 3-6 months, which gradually returned to non-significant levels by 1 year postoperatively. Osteofixation using bioabsorbable plates and screws is comparable to that achieved with titanium in long-term skeletal stability and maintaining pharyngeal airway dimensions. However, a tendency for relapse exists, especially regarding the MPA.

Cephalometric Evaluation of Soft-tissue Profile Changes in Class-II Division 1 Patients with Varied Growth Patterns Treated with all First Premolar Extractions: A Cross-sectional Study

Introduction: Knowledge of the facial skeleton and its overlying soft-tissue is essential in determining facial harmony. Additionally, an individual’s growth pattern may influence posttreatment facial profiles and needs to be considered during treatment planning. Aim: To evaluate the soft-tissue profile changes in treated Class-II malocclusion patients with varied mandibular growth patterns and to compare these changes with patients having a skeletal Class-I relationship and a balanced facial profile. Materials and Methods: The present cross-sectional cephalometric study was conducted in the Department of Orthodontics, Faculty of Dental Sciences, SGT University, Gurugram, Haryana, India, from June 2021 to December 2022. The study included 210 lateral cephalograms of 120 patients. The cephalograms were divided into four groups based on the Frankfort horizontal Mandibular plane Angle (FMA): Group-1 (control, n=30): skeletal Class-I (FMA=22°-28°); Group-2 (n=30): skeletal Class-II with a horizontal growth pattern (FMA&lt;22°); Group-3 (n=30): skeletal Class-II with an average growth pattern (FMA=22°-28°); and group-4 (n=30): skeletal Class-II with a vertical growth pattern (FMA&gt;28°). All patients in the groups2,3, and 4 were treated with all first premolar extractions using a 0.022˝ McLaughlin, Bennett and Trevisi (MBT) appliance. The student’s t-test and post-hoc test was used to analyse skeletal, dental and soft-tissue parameters using Statistical Package for the Social Sciences (SPSS) software (version 22.00 for Windows; SPSS Inc., Chicago, USA). Results: Of the total, 120 patients, 52 were males and 68 females with an age range of 18-28 years. On intergroup analysis, significant changes (p-value&lt;0.05) in the Sella, Nasion and A point (SNA) and Sella, Nasion and B point (SNB) angles were observed in group-3. Clinically insignificant changes were found in the A point, Nasion and B point (ANB) angle across all experimental groups. However, a significant change (p-value&lt;0.001) in the post-treatment ANB angle was observed in group-2, followed by group-3 and 4 when compared with group-1. The soft-tissue profile angle showed a significant change in Group-2 when compared with Group-1 (p-value=0.012). Conclusion: The post-treatment soft-tissue profiles of the experimental groups were comparable to the balanced profile of the control group patients.

The condition of the mandibular bone regenerate in the remote period after compression-distraction osteosynthesis

Was to assess the qualitative and quantitative characteristics of the bone regenerate in the distant period following compression-distraction osteosynthesis. Results from the treatment of 30 patients with mandibular micrognathia, were analyzed. Compression-distraction osteosynthesis (CDO) was performed in the area of the mandibular angle. The patients were divided into two groups: group 1 consisted of 16 patients with congenital micrognathia, and group 2 comprised 14 patients with acquired (post-traumatic) micrognathia. For the assessment of qualitative and quantitative characteristics of the bone regenerate, three-dimensional modeling, morphometric measurements of the regenerate, and evaluation of bone density using the Hounsfield scale through multislice computed tomography were used. The study of the bone regenerate parameters in group 1 yielded the following results: the length of the bone regenerate decreased by 2.14%; the thickness of the bone regenerate increased by 8.75%; the height of the bone regenerate increased by 1.75%. In group 2, the values were 3.14; 3 and 3.76%, correspondingly. In patients of group 1, the length of the mandibular branch increased by 4%; the length of the mandibular body increased by 5.35%. In group 2, the length of the mandibular branch increased by 1.94%; the length of the mandibular body increased by 2.2%. The density of the cortical bone of the regenerate corresponds to the density of the intact bone, while the density of the cancellous bone is slightly reduced. Qualitative and quantitative characteristics of bone regenerate in the long-term period after CDO correspond to the parameters of intact bone. CDO can be considered not only as a preparatory stage for reconstructive operations after the growth of the skull bones has completed, but also as an independent stage of treatment.

Comparison the Effect of Conventional and Nanofat Injection Methods on Nasolabial Fold Lipofilling: A Case- Control Study.

Nasolabial folds are a common sign of aging, accompanied by various manifestations such as skin and tissue loosening, wrinkles, lip corner drooping, mandibular angle loss, platysmal bands, and skin pigmentation changes. Limited research has explored Nanofat injection methods. this study was done with the aim of comparing the effect of fat injection by two methods, conventional and Nanofat, in nasolabial folds. The study conducted in 2020-2021 at the skin clinic in Ilam, western Iran was a case-control study. Participants were divided into two groups, and lipofilling procedures were performed using conventional and nanofat methods with autologous fat. Data collection utilized a researcher-made questionnaire and radiographic results. Follow-up visits occurred on the 30th, 90th, and 180th days to assess complications and recovery rates. After 6 months, participant's photographs were taken and compared with pre-intervention photographs using the GIAS criteria. Data analysis was conducted using SPSS22 version software. The average age of the participants was 37.80±8.30 yr. The treatment response in the conventional fat injection group was significantly better than the nanofat group (P<0.05). Both groups were satisfied with the treatment methods, but high satisfaction was reported in the conventional group, but there was no statistically significant difference between the groups. Both methods of improving wrinkles were effective, but the improvement and response to treatment in the conventional method was better than the Nanofat method, and its effect was felt by the participants for an average period of 3 months.

Clinical and radiographic characteristics of pycnodysostosis: A systematic review.

Pycnodysostosis (PYCD), an autosomal recessive syndrome, is characterized by an imbalance in bone remodeling that produces various clinical and radiographic craniofacial manifestations. This review represents a systematic examination of these manifestations, as well as oral features associated with PYCD. A systematic review was conducted across 8 databases from February to March 2023. The search strategy focused on studies reporting cases of PYCD that examined the clinical and radiographic craniofacial and oral characteristics associated with this syndrome. The review included 84 studies, encompassing a total of 179 cases of PYCD. More than half of the patients were female (55.3%), and the mean age was 14.7 years. Parental consanguinity was reported in 51.4% of the cases. The most common craniofacial clinical manifestation was a prominent nose, observed in 57.5% of cases. Radiographically, the most frequently reported craniofacial characteristics included the presence of an obtuse mandibular angle (84.3%) and frontal cranial bosses (82.1%). Clinical and radiographic examinations revealed oral alterations, with micrognathia present in 62.6% of patients and malocclusion in 59.2%. Among dental anomalies, tooth agenesis was the most commonly reported, affecting 15.6% of patients. Understanding the clinical and radiographic craniofacial features of PYCD is crucial for dental professionals. This knowledge enables these clinicians to devise effective treatment plans and improve patient quality of life.

Effects of Photobiomodulation Using Low-Power Diode Laser Therapy and Nano-bone on Mandibular Bone Regeneration in Rats.

Introduction: Recently, the positive effects of photobiomodulation (PBM) and nano-bone on bone regeneration have garnered significant attention. The purpose of the research was to assess the impact of PBM and nano-bone on the process of mandibular bone repair in mice. Methods: A 4-mm diameter bone defect was created in the left mandibular angle of 24 mice separated into 4 equal groups: group I: control; group II: PBM by irradiation at 100 mW of a 980 nm diode laser for one minute (three sessions per week; day on and day off); group III: nano-bone; group IV: PBM with nano-bone. Every group was sectioned into 3 equal subgroups corresponding to the evaluation method period: (A) one week, (B) two weeks, and (C) four weeks. Histological examination was done with hematoxylin, eosin, and Masson's Trichrome after one, two and four weeks for inflammation, bone defect coverage, vascularization within the newly formed bone, and new bone formation. Statistical analysis of the data was done and presented as percentage values using chi-square. The significance level was set at P value≤0.05 within all tests. Results: In general, by histological examination of the mandibular bone defect of the rats, the intensity of inflammation was the least in group IV when compared with groups II and III and the control group at all evaluation periods (P<0.001). Also, group IV showed a high significant rise in the percentage of new bone formation following four weeks when compared with the control (P≤ 0.001) and groups II and III (P<0.001). Conclusion: The present research results confirmed that the combination of PBM and nano-bone can aid in the repair of mandibular bone abnormalities. This animal study suggests that the use of PBM and nano-bone should be investigated further in clinical studies.

A case report of vascular hamartoma in a rose-ringed parakeet (Psittacula krameri)

Vascular hamartomas, though rare, can manifest in avian species, presenting diagnostic intricacies for clinicians. A 12-year-old male rose-ringed parakeet presented with a mass between the upper and lower mandibular angles on the left side. The mass was surgically removed. Histopathological examination confirmed the diagnosis of a cutaneous vascular hamartoma. The bird recovered uneventfully and 6 months later showed no evidence of recurrence. This report contributes to the understanding of vascular tumors in avian species.

HISTOPATHOLOGICAL VARIANTS OF AMELOBLASTOMA AMONG PATIENTS PRESENTED TO KHYBER COLLEGE OF DENTISTRY PESHAWAR

Objectives: To determine the frequency of diff erent Histopathological variants of Ameloblastoma among patients reporting to the Oral and Maxillofacial surgery unit of Khyber College of Dentistry Peshawar. Materials and Methods: A total of 97 histologically diagnosed cases of Ameloblastoma presented at the Khyber college of Dentistry Peshawar kpk Pakistan, over 18 months period were included in this study and data was analyzed descriptively with respect to the patient’s ages, gender, tumor location, duration, presenting symptoms and radiographic features. Results: Follicular type was found as the most common (64.9%) variety while the least common was Basaloid (2.1%) and Granular type (2.1%). The age range was (11-70 years) with most commonly aff ecting 3rd decade (21 to 30 years) of life, mean ±SD of (32.26 ±11.02 years) and was more frequent in males. Follicular Ameloblastoma was commonly found in the Angle and Ramus region of the mandible. Conclusion: Ameloblastoma aff ects male more frequently than female in the Second and third decades of life. Mandible is more aff ected than Maxilla at posterior portion. The most frequent type of Ameloblastoma is the follicular type, followed by the plexiform, Acanthomatous and desmoplastic type. The granular and Basaloid types were the least frequent.

Skeletal, Dental and Soft Tissue Effects of Twin Block Appliance in Different Facial Divergence Cases

IntroductionClass II malocclusions refer to a discrepancy in the sagittal plane associated with either backward or upward rotation of the jaw. A backwardly positioned mandible is usually managed using a Twin block appliance which contains a bite plane to direct the occlusal forces in a more favorable direction. Our aim was to evaluate skeletal, dental, and soft tissue changes using twin-block appliance therapy in different facial divergence patients. MethodsA cephalometric study was conducted among two groups with 15 patients in each group. Group 1 have a Frankfort Mandibular plane Angle (FMA) of 18-25 degree while Group 2 have an FMA of 28 to 33 degree with Class II Division I malocclusion. All of them were treated with twin block appliances with modifications done according to FMA. Cephalometric analysis was done using Dolphin software (Dolphin Imaging 11.95) to evaluate skeletal, dental, and soft tissue changes after twin block therapy. ResultsAnalysis of variance and paired t-test were used to evaluate pre and post-treatment changes in cephalograms. The position of the mandible, maxillomandibular relation, and mandibular length was changed by 3.99 degrees, 5.23 degrees, and 4.04mm respectively in horizontal growers, while by 2.9 degrees, 1.74 degrees, and 1.07mm respectively in vertical growers. An increment in FMA by 4.59 degrees in horizontal growers with good vertical control and a little increment in FMA by 1.07 degrees in vertical growers were seen. Conclusions The twin block appliance is effective in skeletal, dental, and soft tissue correction in patients with different facial divergences.

HYOID BONE POSITION AND PHARYNGEAL SPACE IN DIFFERENT VERTICAL JAW DYSPLASIAS

Background: The position of hyoid bone and pharyngeal space is affected by various factors. One of the factors is vertical malocclusion. This study aimed to evaluate the position of hyoid bone and pharyngeal space in different vertical jaw dysplasias. Methods: In total 102 lateral cephalograms of 70 females and 32 males in the age range of 15 to 25 years were selected from records of the patients who visited to the Department of Orthodontics and Dentofacial Orthopedics, UCMS College of Dental Surgery Bhairahawa, Nepal. For the vertical plane of the face, sample was divided into three groups based on Frankfort mandibular plane angle: Group 1 (n=34; normal growth pattern) group 2 (n=34; horizontal growth pattern) and group 3 (n =34; Vertical Growth Pattern). Results: The anteroposterior position of the hyoid bone was found significantly forward in horizontal grower compared with normal and vertical grower (p&lt;0.05). There was no statistically significant difference in vertical positioning of the hyoid bone among the patients with different growth patterns. There was no statistically significant difference in the axial orientation of the hyoid bone in patients with different growth patterns. Upper pharyngeal space was significantly different in different facial skeletal patterns (p=0.019) whereas, lower pharyngeal space had no significant association. Conclusions: The position of the hyoid bone in horizontal growth pattern group was more anterior than the vertical growth pattern group. The upper pharyngeal space was found narrower in vertical growth pattern than horizontal and normal growth patterns.

Radiographic imagery of aggressive plexiform-type ameloblastoma in the mandible: a case report

Objectives: This case report aims to describe the radiographic characteristics of plexiform ameloblastoma and its impact on surrounding tissues in a middle-aged female patient using panoramic radiography and CBCT, along with case management. Case Report: A 43-year-old female patient presented to the Dental Radiology Unit of RSGMP UNHAS with a panoramic referral letter, diagnosed clinically with anterior mandibular ameloblastoma. Extraoral examination revealed an asymmetrical facial appearance with anterior mandibular enlargement. Intraoral examination showed mucus membrane enlargement in the anterior mandible region (teeth 37-45), soft consistency, absence of crepitus, no palpation tenderness, and mobility in several anterior mandibular teeth. The first panoramic radiograph (March 16, 2022) exhibited a unilocular radiolucent lesion, well-defined, with scalloped margins in the anteroposterior mandibular region. The second panoramic examination (May 23, 2022) indicated a more aggressive lesion expansion, with evidence of root resorption and destruction of the inferior mandibular cortex approaching the mandibular angle. CBCT findings demonstrated a hypodense/radiolucent lesion extending anteroposteriorly, superiorly, and inferiorly, leading to displacement, root resorption, and destruction of the inferior mandibular cortex in the inferior direction. Conclusion: Based on the characteristics and structure of the lesion observed through various radiographic examinations, a unilocular ameloblastoma was suspected. Histopathological examination confirmed the plexiform-type ameloblastoma.

Bjork-Jarabak Analysis in Different Anteroposterior Skeletal Relationship: A Comparative Study

Aims: This study aimed to evaluate cranial base measurements in individuals with different skeletal relationships (class I, II, and III) using Bjork-Jarabak analysis and compare them with existing research. Material and Method: Lateral cephalograms of 103 Sudanese participants (aged 18-22) were assessed, grouped by ANB angle. Results: Showed no significant differences between class I and II, or class I and III skeletal relationships. However, class II and III relationships exhibited significant differences in Articulare angle, Gonial angle, ramal height, and mandibular length (P&lt;0.0001). Discrepancies in craniofacial morphology were observed between Sudanese and Bjork-Jarabak norms for Caucasian. Conclusion: Saddle angle, Bjork sum of angles, and cranial case showed no significant differences among skeletal classes, but significant differences in several measurements existed between class II and III relationships.

Effects of posterior intrusion using skeletal anchorage on treating anterior open bite: A systematic review and meta-analysis.

Posterior intrusion with skeletal anchorage is one of the effective methods in the treatment of anterior open bite. Knowing the effects of posterior intrusion, the amount of possible molar intrusion using skeletal anchorage, and its impact on clinical and cephalometric indicators can help the clinician choose the optimal treatment method, especially in borderline surgical cases. In this systematic review, a series of articles were collected through a systematic search in databases, and the titles and summaries of all these articles were reviewed. After removing the irrelevant articles, the full texts of the related articles were read carefully, and their validity was evaluated. Only RCTs and observational studies that complied with PICO questions were included. The Cochrane Risk of Bias 2.0 (RoB 2), ROBINS-I, and GRADE were used to assess the risk of bias in the included studies. The relevant information on selected articles was extracted, and a meta-analysis was performed with Review Manager 5.4 software. The meta-analysis revealed a significant average molar intrusion of 2.89 mm using temporary anchorage devices (TADs). A subgroup analysis showed that miniplates achieved greater intrusion (3.29 mm) compared to miniscrews (2.25 mm) (P=0.03). The level of applied force did not significantly affect the degree of intrusion. Dental parameters such as overbite and overjet were notably altered, with overbite increasing by 4.81 mm and overjet decreasing by 2.06 mm on average. As for the skeletal cephalometric characteristics, SNB, ANB, and SN-Pog increased while mandibular plane angle and lower anterior facial height (LAFH) decreased, and these changes were significant. Meanwhile, SNA and palatal angle changes were not significant. TADs have proved effective in achieving significant intrusion of maxillary molars, leading to marked improvements in dental and skeletal characteristics in patients with open bite malocclusion. Miniplates proved more effective in achieving greater intrusion.

Association among craniofacial morphology, ethnicity, and risk of pediatric sleep-related breathing disorders: A multicenter study

Craniofacial morphology and ethnicity may be risk factors for sleep-related breathing disorder (SRBD) in children but have not yet been assessed in an international multicenter study. The objectives of this study were to assess the association among craniofacial features, self-reported ethnicity, and risk of SRBD in children undergoing orthodontic treatment. Children aged 5-18 years who presented for orthodontic evaluation were enrolled in the United States, South Africa, South Korea, Saudi Arabia, and Japan. The risk of SRBD was defined as answering ≥0.33 positive responses to the Pediatric Sleep Questionnaire. Craniofacial features included measurements in sagittal and vertical dimensions to evaluate the cranial base, maxillomandibular and dental relationships, and nasopharyngeal airway dimensions. Logistic regression was performed to assess the association among craniofacial features, ethnicity, age, body mass index, and risk of SRBD. Data were obtained from 602 patients from 5 sites. A total of 76 patients (12.6%) had a risk of SRBD. The mean age was 12.5 years. Male gender (odds ratio [OR], 1.9; 95% confidence interval [CI], 1.0-3.4; P= 0.041), Middle Eastern ethnicity (OR, 10.2; 95% CI, 4.1-25.4; P= 0.001), body mass index (OR, 1.1; 95% CI, 1.04-1.10; P= 0.001), gonial angle (OR, 0.91; 95% CI, 0.85-0.98; P= 0.011), and inferiorly positioned hyoid (OR, 1.1; 95% CI, 1.0-1.2; P= 0.002) were significantly associated with the risk of SRBD. In an ambidirectional cohort study across 5 sites, male gender, Middle Eastern ethnicity, body mass index, gonial angle, and inferiorly positioned hyoid were associated with the risk of SRBD in children undergoing orthodontic treatment.

Vagus Nerve Stimulation in the Carotid Triangle: An Effective Method for Monitoring the Recurrent Laryngeal Nerve in Thyroid and Parathyroid Surgery.

Our objective is the description of the technique of vagus nerve stimulation in carotid triangle in order to monitor the recurrent laryngeal nerve (RLN) during thyroid and parathyroid surgery. We stimulated the vagus nerve in the carotid triangle during 150 thyroid or parathyroid surgeries using a monopolar electromyography electrode inserted under the mastoid process towards the jugular foramen as a cathode, and using another subdermal electrode in the mastoid as an anode. Another complementary method of vagus stimulation was achieved with a pair of subdermal electrodes, placing the cathode at the mandibular angle and the anode at the mastoid. In all patients, compound muscle action potential (CMAP) was recorded in the vocal cords with both stimulation techniques, allowing semi-continuous monitoring to be carried out. Intraoperative lesions were detected in 16 of the cases; 9 of them were transient with CMAP recovery achieved when modifying surgical maneuvers. Vagus nerve stimulation in the carotid triangle is a reliable technique for monitoring the RLN in thyroid surgery. Vagus nerve stimulation in the carotid triangle is effective and safe for RLN monitoring, and it is a clear alternative to direct continuous stimulation of the nerve that by contrast requires its dissection in the carotid sheath.

Pathological mandibular fracture complicated by osteonecrosis in an adult patient with pycnodysostosis: clinical report and review of the literature

Pycnodysostosis is an ultra-rare osteosclerotic skeletal disorder characterized by short stature, susceptibly to fractures, acroosteolysis of the distal phalanges, and craniofacial features (frontal bossing, prominent nose, obtuse mandibular angle, micrognathia). Dental abnormalities (delayed eruption of teeth, hypodontia, malocclusion, dental crowding, persistence of deciduous teeth, enamel hypoplasia, and increased caries) are also frequent; due to bone metabolism alteration, the patients have an increased risk for jaw osteomyelitis, especially after tooth extraction or mandible fracture. Other complications are obstructive sleep apnea, endocrine alterations and cytopenia. Pycnodysostosis is caused by biallelic loss of function variants in CTSK gene, coding the lysosomal protease cathepsin K. CTSK is involved in the degradation of bone matrix proteins, such as type I and type II collagen. In pycnodysostosis, this degradation is decreased, leading to increased bone density and bone fragility with pathological fractures and poor healing.We present a clinical report of a female adult patient with typical pycnodysostosis phenotype. At the age of 52 years, she had a pathological spontaneous fracture of the right mandible complicated by osteonecrosis, treated with load bearing osteosynthesis. The direct sequencing of CTSK gene revealed the presence of the pathogenic homozygous variant c.746T>A, (p.Ile249Asn), that confirmed the diagnosis of pycnodysostosis.We also review the literature case series published to date, that suggest to always consider the diagnosis of pycnodysostosis in case of osteosclerosis, even in the absence of brachydactyly or short stature.This report details the natural history of the disease in this patient, from childhood to adulthood, and highlights the importance of a quality of life assessment. In addition, we describe a case of mandibular osteonecrosis and spontaneous fracture in pycnodysostosis, drawing attention on the maxillofacial complications in these patients and on the importance of a personalized follow-up.

Influence of differences in mandibular incisor inclination on skeletal stability after orthognathic surgery in patients with skeletal class III malocclusion

Objective: The preoperative inclination angle of mandibular incisors was crucial for surgical and postoperative stability while the effect of proclined mandibular incisors on skeletal stability has not been investigated. This study aimed to evaluate the effects of differences in presurgical mandibular incisor inclination on skeletal stability after orthognathic surgery in patients with skeletal Class III malocclusion.Methods: A retrospective cohort study of 80 consecutive patients with skeletal Class III malocclusion who underwent bimaxillary orthognathic surgery was conducted. According to incisor mandibular plane angle (IMPA), patients were divided into 3 groups: retroclined inclination (IMPA < 87°), normal inclination (87° ≤ IMPA < 93°) and proclined inclination (IMPA ≥ 93°). Preoperative characteristics, surgical changes and postoperative stability were compared based on lateral cephalograms obtained 1 week before surgery (T0), 1 week after surgery (T1), and at 6 to 12 months postoperatively (T2).Results: The mandible demonstrated a forward and upward relapse in all three groups. No significant differences in skeletal relapse were observed in the 3 groups of patients. However, the proclined inclination group showed a negative overbite tendency postoperatively compared with the other two groups and a clinically significant mandibular relapse pattern. Proclined IMPA both pre- and postoperatively was correlated with mandibular relapse.Conclusion: Sufficient presurgical mandibular incisor decompensation was of crucial importance for the maintenance of skeletal stability in patients with skeletal Class III malocclusion who subsequently underwent orthognathic surgery.

Taxonomic review of the Calotesversicolor complex (Agamidae, Sauria, Squamata) in China, with description of a new species and subspecies.

Caloteswangisp. nov., a new species of the agamid genus Calotes Cuvier, 1817, from southern China and northern Vietnam, is described. This species can be distinguished from all known congeners by a combination of morphological characteristics and genetic divergence in the mitochondrial tRNA, ND2, and CO1 genes. Molecular phylogenetic analysis revealed that the new species was formed as a monophyletic group and that considerable genetic divergence existed between its congeners (minimum p-distance, 4.6%). Caloteswangisp. nov. is distinguished by a combination of the following characteristics: average SVL < 90 mm for adult males; 10-14 dorsal eyelid scales; scales on side of neck and adjacent shoulder area pointing obliquely upward; keels on neck scales weakly to strongly developed; fold in front of the shoulder absent; pair of dark triangular patches extending from the front of the shoulder to the jaw angles; and orange coloration of the tongue. Caloteswangisp. nov. is similar to C.irawadi but differs in having scales between the nasal shield and the orbit and a fourth toe with a claw that can reach between the eyes and tympanum (even to the snout when hind the limbs are adpressed forward). Phylogenetic analyses revealed two well-supported subspecies, Lineages A and B in C.wangisp. nov., with mean uncorrected p-distances between them of 2%. We propose that Lineage A, which is mainly from the central and southern Wuzhi Mountains on Hainan Island, is a subspecies, C.w.hainanensisssp. nov. Lineage B mainly comprises individuals from other sites on the island plus the adjacent mainland, and is described as subspecies, C.w.wangissp. nov. A diagnostic key to all Calotes species of China is also provided.