Mandibular Deficiency Research Articles

Obstructive Sleep Apnea Treated with Maxillomandibular Advancement Surgery by Computer-Assisted Simulation

This 23-year-old female patient was diagnosed as a severe type of obstructive sleep apnea (OSA), skeletal Class II jaw relation with mandibular deficiency, hyper divergent facial pattern, dental Class II malocclusion, midline deviation and occlusal plane canting. By the assistance of virtual surgical simulation and maxillomandibular advancement (MMA) approaching, patient was satisfied the improvement of functional and esthetic changes after the 18-months treatment.

Expression of DLX6 Gene in Mandibular Deficiency (Retrognathic Mandible): A Randomized Clinical and Genetic Study.

IntroductionThere are various genes that affect craniofacial development and among the important genes that affect jaw development is distal-less homeobox (DLX) 6 genes. The present study was carried out to determine the role of DLX6 gene variations in mandibular deficiency.MethodsThirty subjects having retrognathic mandible were evaluated by clinical examination and assessed using lateral cephalometric radiographs based on cephalometrics for orthognathic surgery (COGS) analysis of hard tissue with N-Pog parameters being less than -13 mm. For the same subjects, saliva samples were taken and sent to biotechnology labs for genetic evaluation. DNA was isolated from salivary samples using a DNA extraction kit and was subjected to polymerase chain reaction (PCR) amplification and sequencing. Single nucleotide polymorphisms (SNP) analysis was done to assess the role of DLX6 gene in these study subjects. Results All 30 subjects showed N-POG parameters of COGS analysis for hard tissue to be less than -13mm, confirming retrognathic mandible. SNP analysis of subjects showed no SNPs in any EXON of the DLX6 gene for all 30 study samples.Conclusion No variations in DLX6 gene were found in the present study. Further studies are required to investigate other genes that could be involved in the cause of retrognathic mandible with a larger sample size and to include subjects in the sample having features other than mandibular retrognathia like hearing loss, abnormal pinnae, ectrodactyly, cleft palate, developmental delay and abnormal teeth to determine the contribution of DLX6 gene variations in mandibular deficiency.

Dental mini-implant designs to support overdentures: Development, biomechanical evaluation, and 3D digital image correlation

Statement of problemCustom mini-implants are needed for edentulous patients with extensive mandibular deficiencies where endosteal placement is not possible. However, the best design for these mini-implants is unclear. PurposeThe purpose of this in vitro study was to develop 2 dental mini-implant designs to support mandibular overdentures and evaluate the effect of their geometries on primary stability and stress distribution. Material and methodsTwo mini-implant designs were developed with changes in the shape, size, and arrangement of threads and chamfers. The experimental mini-implants were made of Grade V titanium alloy (Ti-6Al-4V), (Ø2.0×10 mm) and submitted to a nanoscale surface treatment. Thirty mini-implants (n=10) were placed into fresh swine bones: experimental-threaded, experimental-helical, and a commercially available product model (Intra-Lock System) as the control. The biomechanical evaluations of the experimental mini-implants were compared with those of the control in terms of primary stability, through insertion torque (IT), and with the pullout test. The analysis of stress distribution was performed by using the method of 3D digital image correlation under 250-N axial load and 100-N oblique (30-degree angled model) load. The data were analyzed by ANOVA and the Tukey HSD test (α=.05). ResultsThe IT and pullout test presented a statistically significant difference for all mini-implants (P<.05), with higher IT for the experimental-threaded and maximum pullout force for the control, followed by threaded (P=.001) and helical (P=.001). Regarding the 3D digital image correlation, a lower incidence of stress was found in the cervical third for all mini-implants. No statistically significant differences were found between the designs evaluated (P>.05). ConclusionsComparing the experimental mini-implants with the commercially available control, the experimental-threaded model presented greater primary stability, and all mini-implants showed less stress in the cervical third.

One-year stability of the mandibular advancement and counterclockwise rotation for correction of the skeletal class II malocclusion and high mandibular plane angle: Dental and skeletal aspect

BackgroundThe purpose of this study was to evaluate the stability on dental and skeletal aspect after surgical advancement and counterclockwise rotation for the correction of the mandibular deficiency in patients with high mandibular plane angle (MPA). MethodsWe analyzed the records of patients who had undergone surgical treatment for dentofacial deformities with mandibular deficiency and high MPA. Clinical and radiological data were taken 1 month before surgery (T0), 6 weeks after surgery (T1) and 1 year after surgery (T2). Cephalometric values of the MPA were recorded and compared. The cephalometric changes in the different time periods were defined as follows: A: postsurgical changes (T0–T1), B: one-year changes (T1–T2), and C: short term changes (T0–T2). ResultsTwenty-seven patients had prominent mandibular deficiency with an MPA of over 35° (high angle). The mean age of patients at surgery was 29.7 years. Seven patients had a single jaw procedure, 20 patients had bilateral sagittal split osteotomy (BSSO) combined with a Le Fort I osteotomy, and 14 patients had additional genioplasty. MPA values differed significantly between the time periods (p < 0.05) with an observed relapse of the angle. However, satisfactory clinical improvement was achieved in the dental and skeletal presentation. The overjet improvement was evident from 8.815 ± 2.085 mm (T0) to 3.426 ± 1.253 mm (T2). ConclusionCounterclockwise surgical advancement of the mandible to correct mandibular deficiency in patients with a high mandibular plane angle showed an overall acceptable stability during one-year follow-up.

Association of sleep disturbances and craniofacial characteristics in children with class ii malocclusion: An evaluative study.

Behaviour problems, poor academic performance and failure to thrive are some of the potential sequelae of sleep problems in children. Hence, there is a need to evaluate the prevalence of sleep problems and significant associations in children with skeletal class II malocclusion with mandibular retrognathism. This study aimed to determine associations if any between sleep practices and problems and craniofacial characteristics in children with skeletal class II malocclusion with mandibular deficiency. A cross-sectional study was conducted among a group of children with skeletal class II malocclusion with mandibular retrognathism. Fifty children aged 8-14 years with skeletal class II with mandibular retrognathism and who required myofunctional therapy were selected. A validated sleep questionnaire assessed the sleep practices and problems. A detailed clinical examination including tonsils and evaluation for mouth breathing was performed. A lateral cephalogram recorded specific linear, angular variables as well as upper and lower pharyngeal airway space. Descriptive statistics, frequency, and percentages were calculated, and the Chi-square test was used. All children reported at least one sleep problem, with snoring reported by 76% of the children. Forty-two percent of the children showed a decreased upper airway, whereas 80% showed a decreased lower airway. Significant associations were seen between SN-MP and noisy breathing, upper airway, and snoring with a P value of 0.017. We also found significant associations between upper and lower airway and sleep positions with a P value of 0.021 and 0.005, respectively. All the children exhibited at least one sleep problem. There was a strong association of certain sleep practices and sleep problems with cephalometric variables.

The efficacy of twin block in increasing the mandibular length: A cephalometric study

Introduction: Angle’s Class II Div 1 malocclusion is one of the most common malocclusions in orthodontics. In cases of Angle’s Class II Div 1 malocclusion with mandibular deficiency, myofunctional appliances are often used with the intent of stimulating mandibular growth. Twin block is one of the most popular myofunctional appliances. Aim: The aim of this study was to find out “Does the length of mandible increase with Twin Block appliances” using cephalometric radiograph. Materials and Methods: Cephalometric radiographs of 15 patients who had Class II Div I malocclusion, before and after treatment were examined. The mean changes after Twin Block were compared with pre-treatment parameters using independent‘t’ test. Results: There were statistically significant differences in Pre and Post-treatment mandibular length. Patients treated with twin block appliance showed a mean increase of 4 mm in the mandibular length. Conclusion: Twin Block is an effective myofunctional appliance which can be used to increase the effective mandibular length in patients with skeletal Class II Div I malocclusion. Keywords: Functional appliance, Class II malocclusion, Twin block

Tratamento de Classe II utilizando Propulsor mandibular PowerScope II: Relato de caso clínico

A Classe II de Angle, além de ser uma das más oclusões mais procuradas para tratamento, é também um grande desafio para os ortodontistas. Quando um paciente se apresenta com deficiência mandibular e ainda em fase de crescimento, os aparelhos funcionais, geralmente, são escolhidos para a correção deste problema. Porém, em algumas situações, a falta de colaboração do paciente no uso destes aparelhos, especialmente os removíveis, podem comprometer o resultado do tratamento ortodôntico. Com a evolução dos aparelhos propulsores mandibulares, vários modelos funcionais começaram a surgir no mercado e, dentre estes, o PowerScope, um propulsor fixo híbrido. Entretanto, um dos efeitos esperados de todos os propulsores, sejam eles removíveis ou fixos, além da remodelação dento-alveolar, é a inclinação labial excessiva dos incisivos inferiores. Desta forma, o objetivo desse estudo foi demonstrar o uso do PowerScope II, na correção de Classe II de Angle em um paciente de 12 anos com deficiência mandibular, braquifacial e com incisivos superiores e inferiores vestibularizados. Após planejamento detalhado, optou-se por utilizar aparatologia fixa com prescrição Roth 0,022”, seguida pelo PowerScope II e mini parafusos inferiores bilaterais, como forma de ancoragem, para conter a vestibularização excessiva dos incisivos inferiores. Ao fim do tratamento o paciente manteve o perfil convexo com correção da má oclusão pela compensação dentoalveolar e conseguiu um bom controle de inclinação dos incisivos inferiores. Assim, pode-se concluir que a utilização desse dispositivo associado aos mini parafusos de ancoragem permitem uma abordagem conservadora em tratamentos de Classe II.

Identification of novel susceptibility loci for non-syndromic cleft lip with or without cleft palate.

Although several genome‐wide association studies (GWAS) of non‐syndromic cleft lip with or without cleft palate (NSCL/P) have been reported, more novel association signals are remained to be exploited. Here, we performed an in‐depth analysis of our previously published Chinese GWAS cohort study with replication in an extra dbGaP case‐parent trios and another in‐house Nanjing cohort, and finally identified five novel significant association signals (rs11119445: 3’ of SERTAD4, P = 6.44 × 10−14; rs227227 and rs12561877: intron of SYT14, P = 5.02 × 10−13 and 2.80 × 10−11, respectively; rs643118: intron of TRAF3IP3, P = 4.45 × 10−6; rs2095293: intron of NR6A1, P = 2.98 × 10−5). The mean (standard deviation) of the weighted genetic risk score (wGRS) from these SNPs was 1.83 (0.65) for NSCL/P cases and 1.58 (0.68) for controls, respectively (P = 2.67 × 10−16). Rs643118 was identified as a shared susceptible factor of NSCL/P among Asians and Europeans, while rs227227 may contribute to the risk of NSCL/P as well as NSCPO. In addition, sertad4 knockdown zebrafish models resulted in down‐regulation of sox2 and caused oedema around the heart and mandibular deficiency, compared with control embryos. Taken together, this study has improved our understanding of the genetic susceptibility to NSCL/P and provided further clues to its aetiology in the Chinese population.

Correction of Class II malocclusion with mandibular deficiency via PowerScope appliance

One of Major challenges in managing mild to moderate malocclusion cases involves management of class II malocclusion with mandibular deficiencies during active growth period and are generally treated via myofunctional appliance.Dissent of myofunctional appliance led to the evolvement of fixed functional appliance. Power scope appliance is used as a latest class II corrector in day to day practice. This case report describes the efficacy of power scope appliance as a skeletal class II corrector in a male patient aged 14 years with mandibular deficiency who reported to the clinic with chief complaint of forwardly placed teeth.Levelling and alignment were performed with ideal arch wire sequencing followed by instalment of Power Scope appliance also patient was monitored every month for further adjustment and reactivation of appliance. As a result, Significant changes were seen in mandibular advancement, incisor proclination as well as reduction in over bite and over jet.Anterior movement of soft tissue pogonion lead to notable improvement in facial profile.

Aesthetic rehabilitation in a patient with skeletal mandibular deficiency and open bite: journey from splinted metalloceramic prosthesis to all-ceramic crowns

This case report is of a 31-year-old female who presented with splinted and faulty metalloceramic prosthesis on maxillary anterior teeth, which was responsible for localised periodontal disease and poor aesthetics. At multiple sites the ceramic had chipped off and the prosthesis colour did not match with the adjacent healthy teeth. A multidisciplinary approach of endodontics, periodontics and prosthodontics was employed for this case. The treatment plan consisted of removing the faulty prosthesis, endodontic retreatment of inadequately root-treated teeth and endodontics in the other coronally prepared abutment teeth. Crown lengthening surgery was performed for the correction of periodontal pockets and high smile line and maintenance of an adequate biological width. After periodontal healing, all-ceramic individual crowns were placed on the maxillary anterior teeth along with a three-unit all-ceramic bridge for the replacement of the left upper maxillary first premolar. The final results were aesthetically pleasing with good marginal fit. The patient was extremely satisfied with the outcome as all her concerns were addressed. It is, therefore, advisable to consider placing individual crowns rather than multiunit splinted prosthesis whenever possible.

Arthroplasty Followed by Distraction Osteogenesis Versus Distraction Osteogenesis Followed by Arthroplasty in the Management of TMJ Ankylosis: A Comparative Study.

To compare treatment outcome of arthroplasty followed by distraction osteogenesis (AFD) and distraction osteogenesis followed by arthroplasty (DFA) in the management of mandibular deficiencies in temporomandibular joint (TMJ) ankylosis. A total of 20 patients with TMJ Ankylosis were included in the study. Patients were randomly divided into two groups. Group 1 consisted of patients for whom arthroplasty was done prior to distraction osteogenesis (AFD) for the correction of deficient mandible. Group 2 included patients where distraction osteogenesis was performed prior to arthroplasty (DFA). The treatment outcome was assessed based on maximum interincisal distance, overjet, corpus length, ramus height, upper airway, lower airway, duration of the procedure and the complications for the treatment at the end of 3, 6 and 12months. After the treatment was ended, the patients of both groups had increase in mouth opening and appearance was improved remarkably. There was general increase in all the parameters in both the groups. But at the end of 12months, airway and the ramus height were more stable and the control of the proximal segment was superior in DFA group. Open bite was noticed in 2 cases of AFD group which was treated by elastics. There required additional surgery for the removal of distractors in the AFD Group. Establishing the airway during the surgery was easier in AFD group. The study concludes that distraction followed by arthroplasty was a better procedure for the management of TMJ ankylosis owing to its stable results and less number of surgeries.

Three-Dimensional Evaluation of condylar volume and mandibular length Following Treatment with Skeletally Versus Dentally Anchored Herbst Appliance

Objective: to compare the condylar volume and mandibular length changes of skeletally versus dentally anchored Herbst appliance in the treatment of Class II division 1 patients due to mandibular deficiency. Materials and Methods: The current study was conducted on 17 female patients with their age ranged between 14 and 20 years. All patients were treated by Type IV Herbst appliance. The active group (Group A) comprising 10 patients at whose the Herbst was anchored to the mandible directly by two reconstruction plates located bilaterally in the mandible between the canine and first premolar, while attached to the maxilla through dental splints utilizing orthodontic bands, while the control group (Group B) comprising 7 patients, their CBCT data were taken from a previous study at which the Herbst appliance was anchored with custom made vitalium splints for both the maxillary and mandibular dental arches. The condylar volume and the 3D effective mandibular length was measured using Dolphin software (Dolphin imaging software ver.11.95, Patterson Dental, USA). Statistical analysis was performed with Assistant 7.6 statistics software for Windows (Campina Grande, Paraiba state, Brazil) Results: Condylar volume showed no statically significant change with treatment in both groups, while the 3D effective mandibular length showed statistically significant increase with treatment in both groups. Conclusions: Skeletally anchored Herbst has same mandibular skeletal effect when compared with dentally anchored Herbst.

Is There a Correlation Between Airway Volume and Maximum Constriction Area Location in Different Dentofacial Deformities?

The purpose of the present study was to correlate the airway volume and maximum constriction area (MCA) with the type of dentofacial deformity in patients who required orthognathic surgery. The present retrospective cohort study included orthognathic surgery patients selected from the private practice of one of us. The selected cases were stratified into 5 different groups according to the clinical and cephalometric diagnosis of their dentofacial deformity. The preoperative airway volume and anatomic location of the MCA were calculated using the airway tool of the Dolphin Imaging software module (Dolphin Imaging and Management Solutions, Chatsworth, CA) and correlated with the diagnosed dentofacial deformity. Differences in the pretreatment airway volumes and MCA location were compared among the deformities. The MCA location was more often the nasopharynx for maxillary deficiency and the oropharynx for mandibular deficiency deformities. The nasopharynx volume was significantly smaller statistically (P<.005) for maxillary deficiency plus mandibular excess compared with mandibular deficiency. The hypopharynx volume was significantly smaller statistically (P<.005) for vertical maxillary excess plus mandibular deficiency than for both maxillary deficiency and maxillary deficiency plus mandibular excess. No statistically significant difference was found among the different deformity groups in relation to the mean airway volume (P>.005). The location of the airway MCA seems to have a strong correlation with the horizontal position of the maxilla and mandible. The MCA in maxillary deficiencies (isolated or combined) was in the nasopharynx, and the MCA in mandibular deficiencies (isolated or combined) was in the oropharynx. Clinicians should consider these anatomic findings when planning the location and magnitude of orthognathic surgery movements to optimize the outcomes.

Long-term dentoskeletal changes of class II growing patients' treatment with the propulseur universal light appliance. A prospective controlled study.

Class II is one of the most common malocclusions. The prevailing aspect in Class II patients is a mandibular deficiency. Various removable and fixed functional therapies are used in order to enhance the mandibular growth or position. The aim of this prospectively controlled study was to evaluate long-term dentoskeletal changes obtained by a functional appliance for Class II. Prospective controlled study, based on a sample size calculation. 26 Class II Division 1 patients (11.8±1.5 years) were consecutively treated with the propulseur universal light (PUL) appliance and a multi bracket appliance (PG), they were compared to a sample of 26 Class II untreated patients (11.5±0.8 years) (CG). Lateral cephalograms were taken before and after the PUL therapy, and after multibracket treatment. Interaction analysis was carried out to test whether the PUL parameters in treatment groups were different according to the acquisition times, using the Linear Mixed-Effects Model. Significant ANB, Overjet and WITS differences existed in treatment groups according to the time. In particular, comparing to T1 vs. T0, the relative difference (RD) means in the control group were -0.34, -0.31 and 0.17 for ANB, Overjet and WITS, respectively. The corresponding RD means in the treated group PG were -1.58, -4.27 and -2.38. Comparing to T2 vs. T0, the RD means in the control group were -0.36, -0.51 and 0.63 for ANB, Overjet and WITS, respectively. While the corresponding RD means in the treated group were -2.08, -5.12 and -2.50. The PUL appliance successfully corrected class II malocclusion. The long term correction was mainly due to dentoalveolar effects: therapy success was 91% for overjet correction and 76% for ANB correction. During the post functional appliance period, overjet was stable in 77% of the treated subjects, and ANB in 74% of the treated subjects.

Orthognathic Surgery-Induced Fibrinolytic Shutdown Is Amplified by Tranexamic Acid

Little is known of the systemic effects of oral and maxillofacial surgery on the hemostatic balance, including the biochemical effects of tranexamic acid (TXA), on fibrin clot lysis. The present study investigated the effects of orthognathic surgery on fibrin lysis, fibrin structure, and D-dimer and evaluated the effect of TXA on these fibrinolytic measures. The present double-blind, controlled, and randomized, placebo study included patients referred to the Department of Oral and Maxillofacial Surgery at the University Hospital of Southern Denmark-Esbjerg from August 2014 through September 2016. The patients were elective and had a diagnosis of maxillary or mandibular deficiency, either excessive or asymmetric. All patients underwent bimaxillary orthognathic surgery (OS) with or without maxillary segmentation or additional genioplasty. The patients were blindly randomized to treatment with TXA or placebo. The primary predictor variable was OS. The secondary predictor variable was an intravenous dose of 1g of TXA or equivalent placebo preoperatively. Blood samples were collected before surgery and 5hours after the initiation of surgery. The primary outcome variable was lysis of fibrin. The fibrin structure properties and D-dimer were secondary outcome measures. The Mann-Whitney U test was used for the within-group comparisons. The Wilcoxon signed rank test was used for the between-group comparisons. The sample included 96 patients; 45 received placebo and 51 received TXA. Fibrin lysis decreased after OS (P<.001). The fibrinolytic shutdown decreased significantly more in the TXA group than in the placebo group (P<.001). OS altered the fibrin structure properties with comparable effects in the 2 groups. D-dimer increased postoperatively but significantly less so in the TXA group than in the control group (P<.001). OS is associated with fibrinolytic shutdown and alters fibrin structure properties, driving the hemostatic balance in a prothrombotic direction. The fibrinolytic shutdown is significantly amplified by TXA.

Soft Tissue Esthetic Changes Following a Modified Twin Block Appliance Therapy: A Prospective Study.

ABSTRACTAimAchieving a satisfactory facial esthetics is of utmost importance in the practice of orthodontics. Cl II div 1 patients often suffer from numerous adverse facial characteristics which may impair their social well-being. The objective of the current study was to evaluate the esthetic changes in such patients by using a modified twin block appliance.Materials and methodsSeventy adolescent patients with mandibular deficiency consecutively underwent treatment with a modified twin block appliance for a mean period of 13 months. Soft tissue analyzes of Burstone and Mcnamara were applied to evaluate the changes before and after the treatment. The esthetic changes before and after the therapy were compared using parametric paired t tests analysis. p values less than 0.05 were considered significant.ResultsFacial convexity, lip incompetence, upper lip protrusion, and columellar inclination significantly decreased (p < 0.05) while Merrifield's Z-angle nasolabial angle, lower lip length, and mentolabial angle significantly increased (p < 0.05). Vertical facial height ratio, lower lip protrusion, upper lip length as well as nasal projection and inclination, did not change significantly (p > 0.05)ConclusionOur findings indicated that a modified form of the twin block appliance can be substantially effective in the improvement of several aspects of patients’ facial balance with minimum untoward effects.Clinical significanceAdolescents suffering from mandibular deficiency can gain substantial facial balance with the twin block appliance. The whole face attractiveness, however, is another subject and should not be conflicted with the facial balance.How to cite this articleShahamfar M, Atashi MHA, Azima N. Soft Tissue Esthetic Changes Following a Modified Twin Block Appliance Therapy: A Prospective Study. Int J Clin Pediatr Dent 2020;13(3):255–260.

EFFECT OF HYPERBARIC OXYGEN THERAPY ON THE OSSEOINTEGRATION AROUND IMPLANTS AFTER MANDIBULAR RECONSTRUCTION BY DESTRACTION OSTEOGENESIS

Increases in mandibular width by distraction osteogenesis have recently been shown to be an acceptable and stable treatment option for deficiencies, and also, in the oral rehabilitation, where one of the major problems is the alveolar bone loss, and adjacent soft tissues.Aim: The aim of this study is to evaluate the influence of hyperbaric oxygen therapy (HBOT), on the osseointegration of implants retained partial mandibular overdenture after reconstruction of mandibular deficiency by distraction osteogenesis. Methods: This study was conducted on eight male patients with a lack of the anterior mandibular jaw bone due to anterior marginal mandibulectomy, and partially edentulous maxillary arch (different classes), selected from the maxillofacial outpatient clinic, Faculty of Dentistry, Misr University for Science and Technology, (mean age 43 years, minimum 35 years and maximum 51 years). For all patient, distraction the insufficient alveolar ridge by using an Extraosseous Track Alveolar Distractor (KLS Martin, Germany), after consolidation period, patients received maxillary and mandibular conventional acrylic partial dentures prior to implant insertion. Then, each patient received two endoosseous implants in the mandibular interforaminal region, (following two stage surgical protocols), to retain partial mandibular overdentures. Patients were randomly divided by closed envelops, into two equal groups. Group I; Patients were received hyperbaric oxygen therapy (HBOT), on a protocol of five sequential sessions (study group), while Group II; Patients were received no hyperbaric oxygen therapy (HBOT), as a control group. Ball attachments were screwed to the implants, after four months of surgery. All patients received new mandibular removable partial overdentures were retained by two implants, and designed as Kennedy class IV partial overdentures, to fitted partial mandibular overdentures. Marginal bone height changes and bone density were assessed using cone beam computed tomography(CBCT); at time of prosthetic loading, then after six, and twelve months.Results: Decrease in marginal bone height and increase in bone density through a follow-up period (one year) were observed in both groups , however; group I; that received HBOT revealed less marginal bone resorption and more increase in bone density than group II. Conclusion: After mandibular reconstruction by distraction osteogenesis, hyperbaric oxygen therapy effective treatment, and improve osseointegration around implants retained partial ovedentures, as it associated with increased bone density and reduced marginal bone loss after one year follow up.

Mandibular Distraction Osteogenesis.

Mandibular hypoplasia is a common dentofacial deformity requiring a combination of orthodontic and surgical treatment. Before the introduction of distraction osteogenesis various orthognathic surgical procedures were carried out to treat mandibular hypoplasia. Orthognathic procedures like corpus lengthening by bilateral sagittal split ramus osteotomy and genioplasty are commonly practised all over the world to address the high esthetic demands and functional problems. But hardly there are any established orthognathic surgical procedures to address the deficiency of the posterior part of the mandible that is ramus and condyle. Transverse mandibular deficiency is one of the most difficult problems to be addressed surgically.With the advent of distraction osteogenesis there is a change in concept of addressing mandibular deficiency. Mandibular corpus distraction was first performed by McCarthy et al using an extraoral unidirectional distraction device. The precision of bone lengthening with extraoral distracters did not accurately match the device settings. Since then due to sustained research and design and collaboration with the manufacturers, clinicians have developed various devices to improve the results of mandibular lengthening. Distractor devices of various shape and size are developed for intraoral use in specific anatomical locations of mandible.This presentation will focus on use of intraoral distraction devices on different anatomical locations of mandible. The surgical methods of corpus, ramus, ramuscondylar unit, and symphyseal distraction osteogenesis and associated complications will be discussed in detail.

Orthognathic Surgery Has a Significant Positive Effect on Perceived Personality Traits and Perceived Emotional Facial Expressions in Subjects With Primary Mandibular Deficiency.

This study tested the hypothesis that a layperson's social perceptions of a dentofacial deformity (DFD) patient with primary mandibular deficiency (PMD) are more positive after bimaxillary orthognathic surgery.A survey was implemented comparing layperson's social perceptions of emotional expressions and personality traits before and >6 months after orthognathic surgery when viewing standardized facial photographs. The study sample comprised 20 patients selected randomly from a larger primary mandibular deficiency database, treated by 1 surgeon after orthognathic surgery. The outcome variable was change in 6 perceived emotional expressions and 6 personality traits studied. Descriptive and bivariate statistics were computed (P < .05).Five hundred respondents (raters) completed the survey. The respondents were 52% male with 44% aging from 25 to 34. After bimaxillary and chin orthognathic surgery, primary mandibular deficiency patients were perceived to be significantly more dominant, trustworthy, friendly, intelligent, attractive, and less threatening (P < .05). They were also perceived as happier and less angry, surprised, sad, afraid, or disgusted than before surgery (P < .05).Laypeople consistently report improved social traits in primary mandibular deficiency patient's perceived emotional expressions and perceived personality traits after bimaxillary and chin orthognathic surgery.

A Scope for Advancement

A Scope for Advancement - IDJSR- Print ISSN No: - 2394-708X Online ISSN No:- 2278-3784 Article DOI No:- 10.18231/j.idjsr.2019.016, International Dental Journal of Student's Research-Int Dent J Stud Res