Effect of malocclusion on jaw motor function and chewing in children: a systematic review

Objective To investigate the effects of dental/skeletal malocclusion and orthodontic treatment on four main objective parameters of chewing and jaw function (maximum occlusal bite force [MOBF], masticatory muscle electromyography [EMG], jaw kinematics, and chewing efficiency/performance) in healthy children. Materials and methods Systematic searches were conducted in MEDLINE (OVID), Embase, and the Web of Science Core Collection. Studies that examined the four parameters in healthy children with malocclusions were included. The quality of studies and overall evidence were assessed using the Joanna Briggs Institute and GRADE tools, respectively. Results The searches identified 8192 studies; 57 were finally included. The quality of included studies was high in nine studies, moderate in twenty-three studies, and low in twenty-five studies. During the primary dentition, children with malocclusions showed similar MOBF and lower chewing efficiency compared to control subjects. During mixed/permanent dentition, children with malocclusion showed lower MOBF and EMG activity and chewing efficiency compared to control subjects. The jaw kinematics of children with unilateral posterior crossbite showed a larger jaw opening angle and a higher frequency of reverse chewing cycles compared to crossbite-free children. There was a low to moderate level of evidence on the effects of orthodontic treatment in restoring normal jaw function. Conclusions Based on the limitations of the studies included, it is not entirely possible to either support or deny the influence of dental/skeletal malocclusion traits on MOBF, EMG, jaw kinematics, and masticatory performance in healthy children. Furthermore, well-designed longitudinal studies may be needed to determine whether orthodontic treatments can improve chewing function in general. Clinical relevance Comprehensive orthodontic treatment, which includes evaluation and restoration of function, may or may not mitigate the effects of malocclusion and restore normal chewing function.

Runx2 rs59983488 polymorphism in class II malocclusion in the Indonesian subpopulation

Background: Class II malocclusion is one of the main orthodontic issues for patients in seeking treatment. The prevalence of class II malocclusion varies in different populations. Variation in skeletal profile is mainly controlled internally by a regulatory gene. Runt-related transcription factor-2 (Runx2) plays a role in osteoblast differentiation and is highly expressed during development. Purpose: This study aimed to evaluate the relation of regulatory gene variation in the Runx2 promoter with class II malocclusion. Methods: DNA samples were acquired from 95 orthodontic patients in Jakarta, Indonesia, who were divided into two groups: class I skeletal malocclusion (control group) and class II malocclusion. A single nucleotide polymorphism was investigated using the polymerase chain reaction and restriction fragment length polymorphism techniques. The distribution of alleles was assessed using the Hardy-Weinberg test. The relationship between polymorphism and skeletal variation was assessed with the Chi-Square test and logistic regression. Results: The frequency distributions of genotypes and alleles were tested for Hardy-Weinberg equilibrium and found to be slightly deviated. There was an equal distribution of G and T alleles throughout class II and class I skeletal malocclusions and the Chi-Square test showed that this relationship was not significant (p=0.5). Conclusion: Runx2 rs59983488 polymorphism was found in the Indonesian subpopulation; however, an association between Runx2 rs59983488 polymorphism and class II skeletal malocclusion was not found.

Genes and Pathways Associated with Skeletal Sagittal Malocclusions: A Systematic Review

Skeletal class II and III malocclusions are craniofacial disorders that negatively impact people’s quality of life worldwide. Unfortunately, the growth patterns of skeletal malocclusions and their clinical correction prognoses are difficult to predict largely due to lack of knowledge of their precise etiology. Inspired by the strong inheritance pattern of a specific type of skeletal malocclusion, previous genome-wide association studies (GWAS) were reanalyzed, resulting in the identification of 19 skeletal class II malocclusion-associated and 53 skeletal class III malocclusion-associated genes. Functional enrichment of these genes created a signal pathway atlas in which most of the genes were associated with bone and cartilage growth and development, as expected, while some were characterized by functions related to skeletal muscle maturation and construction. Interestingly, several genes and enriched pathways are involved in both skeletal class II and III malocclusions, indicating the key regulatory effects of these genes and pathways in craniofacial development. There is no doubt that further investigation is necessary to validate these recognized genes’ and pathways’ specific function(s) related to maxillary and mandibular development. In summary, this systematic review provides initial insight on developing novel gene-based treatment strategies for skeletal malocclusions and paves the path for precision medicine where dental care providers can make an accurate prediction of the craniofacial growth of an individual patient based on his/her genetic profile.

A heuristic model for cephalometric diagnosis of sagittal dysplasia

Objective: To identify the best-suited cephalometric parameter for assessing the sagittal skeletal discrepancy in the Indian population. Design: An in vitro, observational, single-blinded, retrospective study. Setting: Department of Orthodontics and Dentofacial Orthopaedics. Methods: A total of 94 lateral cephalograms were used in this study. The study involved one key person and two examiners. The key person collected the radiographs, coded, analysed and classified them into three groups (skeletal classes I, II and III). Subsequently, the coded radiographs were independently analysed by the two examiners. They classified the cases by matching a minimum of 6 out of 11 parameters. On completion of diagnosis by the examiners, the samples were decoded and matched with the original diagnosis given by the key person. The samples in which identification of a particular cephalometric parameter matched the original evaluation as given by the key person was regarded as correctly diagnosed. The number of correctly assessed cases was used to judge the diagnostic performance of all the parameters in all the cases. Cross-validation of the method was performed, and a diagnostic algorithm was developed for diagnosis. Results: β angle and Pi angle showed a positive predictive value of 1 in both skeletal class I and II cases. ANB angle, W angle and HBN angle showed a positive predictive value of 1 in skeletal class III cases. Conclusion: No single cephalometric parameter can independently be used to diagnose sagittal skeletal discrepancy in all cases. However, a conclusive diagnosis on the type of sagittal skeletal malocclusion can be made by using a simple and easy to use diagnostic algorithmic process having a combination of cephalometric parameters.

The effect of concha bullosa and nasal septal deviation on palatal dimensions: a cone beam computed tomography study

Introduction Nasal septal deviation (NSD) and concha bullosa (CB) are associated with airway obstruction in mouth breathers. Mouth breathing is associated with alterations in maxillary growth and palatal architecture. The aim of our study was to determine the effect of the presence of CB and NSD on the dimensions of the hard palate using cone-beam computed tomography (CBCT). Materials and methods A retrospective study was conducted using CBCT scans of 200 study subjects. The study subjects were divided into four groups based on the presence of CB and NSD. Septal deviation angle (SDA), palatal interalveolar length (PIL), palatal depth (PD) and maxillopalatal arch angle (MPAA) were measured in the study groups. Results The presence of NSD and CB was associated with significant (p < 0.001) differences in the palatal dimensions of the study subjects. The PIL and MPA (p < 0.001) were significantly reduced (p < 0.001), whereas the PD was significantly increased (p < 0.001) in study subjects with NSD and CB. There was no significant change in the palatal dimensions between the unilateral and bilateral types of CB. Among the palatal dimensions, the PIL had the most significant association (R2 = 0.53) with SDA and CB. There was a significant correlation between the palatal dimensions and SDA when CB was present along with NSD. Conclusion Based on the results of this study, it can be concluded that the presence of NSD and CB have a significant effect on the palatal dimensions and, therefore, they may be associated with skeletal malocclusion.

Broadening the Scope and Utility of Frontal Sinus Morphology for Predicting the Growth Pattern and Skeletal Malocclusion in Cleft Lip and Palate Cases

Introduction: The three dimensionally affected growth and development of craniofacial structures in CLCP leads to problems dealing with facial appearance, skeletal and dental malocclusion, feeding, airway, hearing, and speech. Objectives: Evaluation and utilisation of fs morphology as a forecast of future growth for growth pattern and skeletal malocclusion in CLCP cases. Methodology: A 30 Cases from Skeletal Class I, III and CLCP will be selected from Department of Orthodontics. Dimensions and area of frontal sinus is evaluated using 3DVT. Parameters are evaluated in sagittal and coronal section. The measurement's dependability will be determined using a reliability test (Cronbach alpha test). Chisquare Test, One Way ANOVA, and Multiple Comparison will be used to do descriptive and analytical statistics. The Tukey Test is a statistical test that is used. Expected Results: Frontal sinus dimensions when observed for Class III will be found greater. Average dimensions will be observed for skeletal Class I cases. Based on the dimensions of frontal sinus observed in cleft lip and palate, we can predict the skeletal malocclusion and growth pattern. Conclusion: The morphology of the fs is evaluated in cleft cases for the upcoming growth pattern and skeletal malocclusion if is known during formulating a treatment plan for the three dimensionally affected jaw bases and craniofacial structure the requirement for later surgical intervention can be prevented.

Glenoid fossa position in skeletal class-II malocclusion due to retrognathic mandible and skeletal class-I malocclusion in Pakistani population

BACKGROUND & OBJECTIVE: Different dental and skeletal abnormalities interact with each other to cause multiple malocclusions of various areas of the dentofacial region. Association of the mandible and cranial base influence the malocclusions in anteroposterior and vertical dimensions that influences the evaluation of the skeletal components of a particular patient, so the relationship of glenoid fossa to adjacent craniofacial components must be taken into account. This research is conducted for the comparison of glenoid fossa position in subjects presenting with class II skeletal malocclusion due to retrognathic mandible and class I skeletal malocclusion. METHODOLOGY: Standardized lateral cephalograms of 130 patients were selected according to inclusion criteria from the orthodontic department. These radiographs were traced, and different angular and linear measurements were recorded. Then the position of glenoid fossa was compared in subjects of class II malocclusion with retrognathic mandible and class I malocclusion. SPSS version 17 was used for data analysis. Cephalometric measurements were analyzed, and glenoid fossa position was compared in both groups by using student’s t-test. Statistical level of significance using student t test was p< 0.05 RESULTS: Position of glenoid fossa in subjects with class II malocclusion is more distal and posterior as compared to the subjects with class I malocclusion. The effective parameters for the measurements of glenoid fossa are GF-S on FH, GF-Ptm on FH, and GF-FMN with p value 0.0001. CONCLUSION: A distally and posteriorly placed glenoid fossa is an important diagnostic feature of Class II skeletal malocclusion with the retrognathic mandible.

Age-related osteogenesis on lateral force application to rat incisor – Part II: Bony recession and cortical remodeling

Objective: The aim of this study is to analyze the age-related changes in the bony recession and cortical bone remodeling induced by lateral orthodontic tooth movement, using a three-dimensional micro-computed tomography (CT) analysis. Material and Methods: A total of 40 male Sprague-Dawley rats were divided into two distinct age groups (young, 10 weeks and adult, 52 weeks). Double-helical springs exerting 40 g of force were applied to central incisors to analysis of changes in lateral cortical bone and tooth movement with age and time. The young and adult rats were divided into four subgroups, T0 (0 week), T1 (1 week), T2 (2 weeks), and T3 (3 weeks), depending on the period of wearing the appliance. Micro-CT image was taken on each dissected pre-maxilla specimen. In each subgroup, distance between the center of teeth, suture width, tooth displacement, bony recession, and bone volume was evaluated. Results: The changes in the distance between the center of teeth and the suture width were significantly greater in the young group. However, the change in the tooth displacement showed no significant difference between groups. In the young group, bony recession of outer cortical layer was observed at T1 (P < 0.05), but the amount of recession gradually decreased at T2 and T3. In contrast, in the adult group, bony recession increased gradually over observation period (P < 0.05). The bone volume decreased at T1 (P < 0.05), but recovered at T2 and T3 in both groups. Conclusion: The compensatory bone formation occurs in the pressure side of cortical bone more significantly in the young group than in the adult according to the lateral displacement of incisor in rats. The reduced bone reaction in the adult is considered a limiting factor of the excessive tooth movement in the compromised treatment of skeletal malocclusion.

Indian Board of Orthodontics Case Report: Management of Class II Skeletal Malocclusion Using 2-Phase Treatment

KL, a 12-year-old boy, presented with a class II Div I malocclusion on a class II skeletal base (retrognathic mandible) with a 7-mm overjet and a horizontal growth pattern. He had a convex profile, incompetent lips, lip trap, deep mentolabial sulcus, everted lower lip, and positive visual treatment objective (VTO). KL had a CS2 cervical maturation stage, which indicates 65% to 85% adolescent growth remaining. Treatment involved growth modification using a removable Twin Block with midpalatal expansion screw. This was followed by upper and lower fixed appliance using 0.022” × 0.028” slot Mclaughlin Bennet and Trevisi (MBT) prescription. The retention protocol involved upper wrap around and lower lingual bonded retainer.