Role of the Growth Hormone Receptor (GHR) Gene in Skeletal Class II Malocclusion and Its Significant Influence on the Skeletal Facial Profile in Both the Sagittal and Vertical Dimensions: A Systematic Review.

This systematic review aims to determine the role of the growth hormone receptor (GHR) gene in skeletal malocclusion and its significant influence on the growth of the maxilla and the mandible in both sagittal and vertical dimensions. A search of the electronic databases of PubMed, Google Scholar, and Cochrane up to and including the year 2023 was made. In addition to this, a hand search of orthodontic and dentofacial orthopaedic journals was carried out. This search included randomized control trials. The Mesh terms used were "skeletal class II malocclusion", "mandibular retrognathism", "sagittal malocclusion", "genetic expression", "genetic factors", "genetic study", "genetic polymorphism", and "single nucleotide polymorphism". The inclusion criteria included studies such as clinical trials and orthopaedic appliances in the presurgical phase. The exclusion criteria for the study were studies not in the English language, case reports, case series, and studies with irrelevant data. It has been cited in various literature that polymorphic variations of the GHR gene could cause variations in mandibular morphogenesis affecting both the mandibular body length and ramal height. However, its effects are quite variable and are based on different population groups. Polymorphism of the GHR gene can be considered a reliable indicator predicting variations in affecting the growth of the mandible with greater significance in affecting the vertical ramal height compared to the body length of the mandible. Its effects on the maxillary skeletal base are rather limited comparatively.

Anatomical Analysis of Inferior Alveolar Nerve Relation to Mandibular Posterior Teeth Using Cone Beam Computed Tomography: A Retrospective Radiographic Analysis Study.

Introduction: Cone beam computed tomography (CBCT) is reliable in the assessment of structures related to teeth. The assessment of the inferior alveolar neurovascular (IAN) bundle location using CBCT is considered one of its prime uses in different mandibular surgeries. Methodology: Retrospective CBCT data of patients presented to the institute were assessed to measure relations of IAN. Measurements were taken to assess the bone thickness adjacent to IAN, the superior-inferior dimension between the canal and the teeth, and the dimension between the canal and the inferior border of the mandible. Results: Out of the 170 patients the root apices nearest to the IAN were that of the second molars (1.76 ± 1.86 mm). The IAN was closest to the inferior border of the mandible at the roots of the second molars (8 ± 3.4 mm). The buccal bone thickness had its greater dimension buccal to the IAN at the area of the second molar (5.16 ± 1.26 mm). Conclusion: Two mini-plates in trauma do not increase the risk of injury. It is advisable in apicectomy not to extend 1.5 mm apically. The thickness of the nerve-lateralization window should not exceed 2 mm. In body osteotomy procedure, perform surgery anterior to premolars as much as possible.

Quantitative structural analysis of hemifacial microsomia mandibles in different age groups.

Introduction: This study aims to quantitively analyze mandibular ramus and body deformities, assessing the asymmetry and progression in different components. Methods: This is a retrospective study on hemifacial microsomia children. They were divided into mild/severe groups by Pruzansky-Kaban classification and into three age groups (<1 year,1-5 years, 6-12 years old). Linear and volumetric measurements of the ramus and the body were collected via their preoperative imaging data to compare between the different sides and severities, using independent and paired tests, respectively. The progression of asymmetry was assessed by changes in affected/contralateral ratios with age using multi-group comparisons. Results: Two hundred and ten unilateral cases were studied. Generally, the affected ramus and body were significantly smaller than those on the contralateral side. Linear measurements on the affected side were shorter in the severe group. Regarding affected/contralateral ratios, the body was less affected than the ramus. Progressively decreased affected/contralateral ratios of body length, dentate segment volume, and hemimandible volume were found. Discussion: There were asymmetries in mandibular ramus and body regions, which involved the ramus more. A significant contribution to progressive asymmetry from the body suggests treatment focus in this region.

Comparison of Mandibular Volume and Linear Measurements in Patients with Mandibular Asymmetry.

In patients with mandibular asymmetry, the volume of the mandible divided by the mandibular median plane is significantly larger on the non-deviated (N-Dev) side than on the deviated (Dev) side. However, it has been reported that there is no significant difference between the volumes of the N-Dev and Dev sides when the mandibular ramus and body are divided. The purpose of this study was to investigate which region is responsible for the volume difference between the N-Dev and Dev sides. Cone Beam Computed Tomography (CBCT) images of patients with mandibular asymmetry were analyzed by measuring the volume, and linear analysis of the mandibular body, ramus, and condyle on the N-Dev and Dev side was performed. In this study, CBCT images of 37 patients (8 Japanese, 16 Korean, and 13 Egyptian) aged ≥ 18 years with mandibular asymmetry (men: 20, women: 17) were used to evaluate mandibular asymmetry. In patients with mandibular asymmetry, the N-Dev side showed significantly larger values than the Dev side for both volume and linear condyle, ramus, and mandibular body measurements. These results do not differ according to sex or ethnicity. Therefore, it is suggested that the N-Dev side of mandibular asymmetry is large without any regional specificity in pathophysiology.

Conservative management of pediatric mandibular distal fractures-A retrospective study.

BACKGROUND/AIM: Pediatric mandibular distal fractures present unique treatment challenges which are usually managed with open reduction and internal fixation (ORIF) with the risk of developing tooth bud injuries. Conservative management through maxillomandibular fixation (MMF) with orthodontic bracket-elastic as an out-patient department (OPD) service has been used for these fractures presenting with derangement of occlusion. The aim of this study was to retrospectively analyze MMF with orthodontic bracket-elastic as a treatment method and its outcome for management of pediatric mandibular distal fractures. METHODOLOGY: Data of seventeen pediatric cases diagnosed with displaced mandibular distal fractures managed with MMF with orthodontic bracket-elastic over a period of 5 years were analyzed. In this technique, two weeks of immobilization and one week for guiding elastics were used. RESULTS: The mean age of patients was 7.6 ± 1.6 years with a mean follow-up of 24 months. All fractures healed uneventfully with satisfactory occlusion. The cases included 23.5% minimally displaced, and 64.7% moderately displaced and 11.8% significantly displaced fractures with step deformity with successful remodeling of the lower border contours over a duration of 18 months ± 1 month. The developing tooth buds in the fracture line showed no complications except for root dilacerations/malformation (n = 3). CONCLUSION: MMF with orthodontic bracket-elastic is a viable and conservative technique for the management of pediatric mandibular distal fractures which need to be verified through randomized trials for generalization of the results.

Stability of bioresorbable plates following reduction of mandibular body fracture: Three-dimensional analysis.

PURPOSE: The recent development of bioresorbable bone plates and screws allows plates to be applied to the load-bearing regions of the mandible and to remain in place over time without the need for removal. We hypothesized that the stability of composite plates and screws forged from unsintered hydroxyapatite particles and poly-l-lactide (u-HA/PLLA) is comparable to that of standard titanium fixation systems for the reduction of fractures of load-bearing regions of the mandibular body. MATERIALS AND METHODS: 40 patients underwent open reduction and internal fixation of the fractured mandibular body with either a titanium or u-HA/PLLA bone plate. Cone-beam CT images were obtained immediately postoperatively and at 6-month follow-up, and were analyzed for positional changes of the affected mandible. RESULTS: There were no significant differences in the postoperative positional changes of reference points between the titanium and u-HA/PLLA miniplates, except for that for the coronoid process (p-value = 0.03). Multivariate regression analysis revealed no significant differences in spatial changes between the immediate postoperative and 6-month follow-up images, after adjusting for age and sex. CONCLUSION: The stability of bioresorbable u-HA/PLLA miniplates and screws was comparable to that of titanium miniplates and screws immediately postoperatively and at 6-month follow-up, following surgical reduction of fractures of load-bearing regions of the mandibular body. Bioresorbable osteosynthesis can be considered a viable alternative to titanium osteosynthesis.

Morphometric analysis of the mandible in the Durban Metropolitan population of South Africa.

BACKGROUND: The identification of an individual from skeletal remains plays a vital role in forensic investigation as it is essential for the identification of the individual's age, sex, and/or race and further analysis. Skeletal characteristics differ from one population group to another since population-specific osteometric standards exist for sex determination. Since the mandible is the largest, strongest and most durable compact facial bone, it is the best preserved after death. While sexual dimorphism of the mandible is indicated by its shape and size, morphometric analysis is more accurate in the determination of sex from the skull. The aim of this study was to evaluate the morphometric parameters of the mandible in the Durban Metropolitan population. MATERIALS AND METHODS: Various morphometric parameters of the mandible were measured and assessed in 265 digital panoramic radiographs aged between 16 and 30 years (n = 530). Each parameter recorded was statistically analysed using SPSS to determine if a relationship existed between the parameter, and sex and age. RESULTS: In this study the morphometric parameters of the male mandibles were greater than that of the females. This concurred with the findings of previous studies. The length of the mandibular ramus on the right and left sides was statistically significant with sex. CONCLUSIONS: This correlated with previous studies, indicating that the length of the mandibular ramus generally has higher sexual dimorphism than any other morphometric mandibular parameter (p = 0.000). However, only the length of the right mandibular body was statistically significant when compared with sex (p = 0.040). The findings of this study may assist forensic investigators, anatomists, anthropologists and maxillo-facial surgeons.

Change in mandibular body height at the site of a fixation plate in the advance (lengthening) and setback (shortening) sides after sagittal split ramus osteotomy.

PURPOSE: The purpose of this study was to evaluate changes in mandibular body height at the site of a fixation plate in the advance (lengthening) and setback (shortening) sides after sagittal split ramus osteotomy (SSRO). SUBJECTS AND METHODS: The subjects were 49 patients (98 sides) who underwent bilateral SSRO surgery. The subjects were divided into 4 groups as follows, setback (shortening) sides in mandibular prognathism (Prog S group; n = 42), advancement (lengthening) sides in mandibular retrognathism (Retro L group; n = 24), setback (shortening) sides in mandibular asymmetry (Asym S group; n = 16) and advancement (lengthening) sides in mandibular asymmetry (Asym L group; n = 16). Postoperative computed tomography (CT) was analyzed for all patients pre-operatively, and at 1 week and 1 year postoperative. Mandibular body height at the site of the fixation plate, mandibular upper height above the plate and mandibular lower height under the plate were measured by 3-dimensional (3D) CT. RESULTS: There were no significant differences in mandibular height between the lengthening and shortening sides in mandibular prognathism, retrognathism and asymmetry in the time-course change. Upper mandibular height at the mid-point of the fixation plate after 1 year was significantly smaller than that after 1 week in all sides (P < 0.05). CONCLUSION: This study suggested that slight bone resorption could occur at the upper site of a fixation plate after set back and advancement SSRO.

Rare Locations of Epidermoid Cyst: Case Reports and Review.

BACKGROUND: Epidermoid cysts are benign lesions encountered throughout the body. Eighty percent of epidermoid cyst seen in ovaries and testicles, whereas in head and neck region they account for only 1.6-7.0%. 1.6% of epidermoid cysts occur in oral cavity and they account for 0.01% of all the oral cavity cysts. CASE DETAILS: Two case reports of epidermoid cyst has been discussed. One patient reported with well defined swelling in the right lower one third of the face, another one in the upper lip. Initially the cases were diagnosed as Lipoma and salivary adenoma respectively but histologically they turned out to be epidermoid cyst. Hence, we aim at highlighting the differential diagnosis pertaining to the anatomical location. The PubMed database search made on January 2016 yielded 674 articles of epidermoid cyst in the head and neck region. In that there is only one case reported occuring in the lower one third of face. In the current report, we outline the second case of epidermoid cyst localized to the right mandibular body region without bone involvement. Another case in our report was localized in the upper lip. In the literature totally seven cases were reported till now occurring in the lip. CONCLUSION: Although epidermoid cysts are rarely encountered in the oral cavity, the possibility that they may occur warrants the need for successful management to avoid misdiagnosis.

Frequency of mandibular asymmetries evaluated by cone beam computed tomography at a radiology diagnostic center in Medellin, Colombia: 2011-2013 / Frecuencia de asimetrias mandibulares evaluadas por tomografia computarizada cone beam de un centro de diagnóstico radiológico de Medellín,Colombia: 2011-2013

Longitudinal differences on the left and right sides of the jaw with respect to the midline in three spatial planes are called mandibular asymmetries. Objective: To determine the frequency of mandibular asymmetries in three spatial planes by means of Cone Beam computed tomography (CBCT) and classify them according to the degree of difference between both sides. Methods: A total of 40 Cone Beam volumetric tomography (New Tom 3G Cone Beam Volumetric tomographic scanner) records were analyzed using simple random sampling of patients between the ages of 18 and 70 from 2011 until 2013. Axial slices were obtained from the lingula in cranio-caudal direction every 5 mm until the gonial angle. Results: From the records, 2.5 percent showed moderate degree of difference in the length of the mandibular body with predominance on the right side. For breadth of the ramus, predominance was found on the left side. In the length of the mandibular ramus, 10 percent presented moderate degree of predominance on the right side. Conclusions: 1) asymmetries are more frequent at the level of the mandibular ramus thickness; (2) moderate and severe degrees of differences are most frequently found in the mandibular ramus thickness. 3) It is not possible to proportionally determine mandibular ramus thickness only with a 2D image...

Se denominan asimetrías mandibulares a las diferencias longitudinales de los lados derecho e izquierdo de la mandíbula con respecto a la línea media en los tres planos espaciales. Objetivo: Determinar la frecuencia de asimetrías mandibulares en los tres planos del espacio por medio de tomografía computarizada Cone Beam (TCCB) y clasificarlas según el grado de diferencia entre ambos lados. Métodos: Se analizaron 40 registros de tomografía volumétrica Cone Beam, (New Tom 3G Cone Beam Volumetric Tomographic Scanner) mediante muestreo aleatorio simple de pacientes entre los 18 y 70 años de edad, entre los años 2011 y 2013. Se obtuvieron cortes axiales a partir de la língula en sentido cráneo-caudal cada 5 mm hasta llegar al ángulo goníaco. Resultados: El 2,5 por ciento de los registros presentaron diferencias moderadas en la longitud del cuerpo mandibular con predominio del lado derecho. En la amplitud de la rama se encontró predominio del lado izquierdo. En la longitud de la rama mandibular el 10 por ciento presentó predominio moderado del lado derecho. Conclusiones: 1) las asimetrías más frecuentes se encuentran a nivel del grosor de las ramas mandibulares. 2) Los grados de diferencias moderados y altos se presentan con mayor frecuencia en el grosor de las ramas mandibulares. 3) No es posible determinar proporcionalmente el grosor de las ramas mandibulares obteniendo solo una imagen 2D...

Clinical and radiographic evaluation of biodegradable bone plates in the treatment of mandibular body fractures.

BACKGROUND: Many different systems are available for the treatment of fractures ranging from the heavy compression plates for mandibular reconstruction to low profile plates for mid-facial fixation, and are made either from stainless steel, titanium or vitallium. Recently, biodegradable, self-reinforced polylactide plates and screws have been used for the internal fixation of fractures of the mandible with good results. AIM OF THIS STUDY: This study evaluated clinically the biodegradable bone plates for treatment of mandibular body fracture and to evaluate bone healing during the follow-up period using digital radiography. MATERIALS AND METHODS: Eight patients had been suffered from mandibular body fractures were treated using Inion CPS(TM) bioresorbable fixation system and the healing process were followed up using digitised panoramic radiography at first week and after 1, 3 and 6 months. RESULTS: Clinical examination of fractured segments revealed stable fixation across the fracture sites while visual and quantitative assessment of radiograph showed healing process was comparable with results previously reported by titanium bone plates. CONCLUSION: Open reduction and internal fixation of mandibular fractures using bioresorbable fixation system with a brief period of inter-maxillary fixation have evolved to the point where the physical properties are sufficient to withstand the post-operative loads required for fracture repair of mandibular body fractures. The foreign body reaction is a major material-related problem which requires further studies.

Clinical study of microsplint and circumferential wiring in the treatment of mandibular body fracture in children / 实用口腔医学杂志

Objective:To evaluate the application of microsplint and circumferential wiring in the treatment of mandibular body frac-ture in children.Methods:23 children with mandibular body fracture were treated by microsplint and circumferential wiring from 2009 to 2012,the effects of treatment were assessed.Results:Treatment with microsplint and circumferential wiring did not injure perma-nent teeth germ.It showed many features,such as easy reduction of fractured bone segments,stable fixation,without interfere with eat-ing and benefit of mouth clearness.Conclusion:Microsplin and cicumferential wiring is effective for the treatment of mandibular body fracture in children.

The successful recovery of low copy number and degraded DNA from bones exposed to seawater suitable for generating a DNA STR profile.

A universal method allowing for DNA profiling from bones exposed to seawater has not been reported yet. This study refers on the identification of a body immersed in seawater for 8 months. The biological material for identification was the mandibular body, usually characterized by low success rates of DNA analysis. Initially, two extraction protocols were performed with negative results: one used for bones immersed in fresh water and a silica-column procedure. A third protocol was performed, which combined the extraction of a higher amount of bone powder, the use of multi-silica-based extraction columns followed by a concentration step. This protocol allowed to obtain low copy number DNA and to generate a 12-loci STR profile by combining conventional STR typing and mini-STR technologies. This protocol could be suitable when human bones have been exposed to severe environmental conditions, and the available nuclear DNA is highly degraded and in low copy number.

The use of mandibular body distraction in hemifacial microsomia.

OBJECTIVE: The goals of treatment for hemifacial microsomia include horizontalization of occlusal plane and acquisition of facial symmetry. Although horizontalization of occlusal plane can be easily achieved, facial symmetry, particularly in relation to mandibular contour, can be difficult to attain. Soft tissue is generally reconstructed to correct facial asymmetry, and no studies have described correction of facial asymmetry through skeletal reconstruction. CASE: A 12-year-old girl presented with grade IIb right-sided hemifacial microsomia. She was treated using Nakajima's angle-variable internal distraction (NAVID) system for mandibular body distraction. RESULTS: Following treatment, appropriate facial symmetry was achieved, and the patient was extremely satisfied with the results. CONCLUSIONS: Thus, we successfully treated the present patient by our novel method involving distraction osteogenesis. This method was effective and useful for several reasons including; the changes were not accompanied by postoperative tissue absorption, donor sites were not involved, and the treatment outcome could be reevaluated by adjusting distraction while the patient's appearance was being remodeled.

Management of mandibular body fractures in pediatric patients: a case report with review of literature.

Mandibular fractures are relatively less frequent in children when compared to adults, which may be due to the child's protected anatomic features and infrequent exposure of children to alcohol related traffic accidents. Treatment principles of mandibular fractures differ from that of adults due to concerns regarding mandibular growth and development of dentition. A case of a 4.5-year-old boy with fractured body of mandible managed by closed reduction using open occlusal acrylic splint and circum mandibular wiring is presented. This article also provides a review of literature regarding the management of mandibular body fracture in young children.

Cemento-Ossifying Fibroma in the Fracture Area of Mandibular Body: a Case Report

Mesenchymal chondrosarcoma on the mandibular body: a case report

Mesenchymal chondrosarcoma is a rare malignant tumor of bone and soft tissue. This aggressive form of chondrosarcoma represents only 3% to 9% of all chondrosarcomas. This neoplasm is characterized by sheets or clusters of undifferentiated spindle or round cells surrounding discrete nodules of well-differentiated cartilage. We experienced a case of mesenchymal chondrosarcoma on mandibular body. Two years ago, the patient had been treated the intrabony cystic lesion on mandiblular left body. At that time, cartilage portion was not detected in the cystic specimen. Two years after cyst enucleation, the recurred large neoplasm in the mandibular left body was noted, and it was diagnosed as 4.5 cm sized mesenchymal chondrosarcoma. The mandibular tumor was widely resected and rigid-plate and cervical musculocutaneous flap were used for reconstruction of resected bone and soft tissues. No complications and recurrence were noted for 6 months postoperatively.