Mandibular symphysis dimensions in different sagittal and vertical skeletal relationships (original) (raw)
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Head & Face Medicine, 2013
Introduction: The purpose of this study was to identify possible dentoskeletal parameters associated with variation of anterior tooth inclination in Angle Class II subdivisions. Methods: Pre-treatment lateral radiographs of 144 Class II patients (68 males, 76 females) aged 9 to 17 years were classified for upper incisor inclination into three groups (proclined, normally inclined, retroclined) homogeneous for gender and skeletal jaw relationship. The effect of age on the 22 cephalometric variables was controlled by covariance analysis.
Geometric Morphometric Analysis (GMA) Of Mandibular Symphysis In Class Iii Skeletal Base Patients
SciDoc Publishers, 2021
Objective: To investigate the mandibular symphysis (MS) shape variation among adolescents, emerging adults, and adults with Class III skeletal base, using geometric morphometric analysis. Materials and Methods: Pre-treatment lateral cephalometric radiographs of 254 patients aged between 11-40 years old, with Class III skeletal base (ANB <1 o) and lower incisor angle (LIA <99 o) were included. The sample was divided in to adolescents, emerging adults, and adults based on gonial angle (>130 o : high angle, 120 o-130 o : average angle and <120 o : low angle). Nine landmarks with x and y coordinates were identified on MS. Shape and statistical analysis carried out using Morpho J version 1.06d (Klingenberg Lab, Manchester, UK). Results: In high gonial angle group, adults had significantly narrower alveolar and basal part of MS (p=0.003) while emerging adults had significantly narrower alveolar part of MS (p=0.01) compared to adolescents. In average gonial angle group, only adults had a significantly narrower alveolar and basal part of MS compared to emerging adults (p=0.007) and adolescents (p<0.0001). Low gonial angle group showed wider and shorter MS with no significant shape variation for all age groups. Multivariate regression showed significant shape variation of MS shape with increasing age (p<0.0001). Conclusion: The shape of the MS can be affected by age groups where significant MS shape variation observed between adolescents, emerging adults, and adults. Hence, understanding the shape variation of MS especially in adults with high gonial angle is important during orthodontic treatment planning to avoid unwanted complications.
BMC Oral Health, 2021
Background This study is aimed to (1) investigate the influence of sagittal and vertical patterns on mandibular cross-sectional morphology and to (2) provide visualized mandibular cross-sectional morphology in different groups with General Procrustes Analysis (GPA), canonical variance analysis (CVA) and discriminant function analysis (DFA). Methods 324 cone-beam computed tomography (CBCT) images were collected to analyze mandibular cross-sectional morphology and were categorized into 12 groups according to sagittal and vertical pattern and gender. One-way analysis of variance (ANOVA) was used to compare the difference among the groups. Thirty equidistant points were marked along the contour of mandibular cross-section and GPA, CVA and DFA were applied. Results (1) Mandibular height in hyperdivergent groups was significantly higher than that in normodivergent and hypodivergent groups (P 0.05). (3) Class II hyperdivergent group showed narrowest lower third width in the molar region, ...
Relationship between mandibular symphysis dimensions and skeletal pattern in adults
Folia morphologica, 2021
BACKGROUND The knowledge of dimensions of the symphysis is important for morphological and orthodontic studies. This research evaluates the association between mandibular symphysis dimensions and anteroposterior and vertical skeletal patterns in adults. MATERIALS AND METHODS This cross-sectional cephalometric study included 90 lateral cephalograms of untreated subjects presenting for orthodontic treatment. The inclusion criteria were adults with lateral cephalograms showing the symphyseal region and anterior cranial base. One investigator traced and analyzed all cephalograms. Symphyseal height, thickness, and ratio between height and thickness were measured in relation to seven anteroposterior and vertical skeletal measurements in females and males. RESULTS Symphyseal measurements were associated with SNAo (anteroposterior) in females and Gonial angle (vertical) in males. When analyzed by anteroposterior skeletal classification (ANBo), no significant differences in symphyseal dimens...
Geometric morphometric analysis of mandibular symphysis in Class III skeletal base
Anatomy & Cell Biology, 2022
This study aimed to investigate the general mandibular symphysis (MS) shape variation among Class III skeletal base, using geometric morphometric analysis. Pre-treatment lateral cephalometric radiographs of 254 patients aged 11-40 years old, with Class III skeletal base (ANB <1 o) and lower incisor angle (<99 o) were included. Nine-landmarks with x and y coordinates were identified on MS using TPSDig2 software, then exported into Morpho J for shape and statistical analysis. Principal component analysis showed that three main shape dimensions with a total variance of 74.6% represented the majority variation of samples. Procrustes Anova showed the shape of MS in Class III skeletal base to be mainly influenced by gonial angle, incisor inclination and sex (P<0.0001). Canonical variate analysis showed that high gonial angle groups had significantly narrower and elongated MS whereas low gonial angle groups had wider, bulbous and rounded MS (P<0.0001). The ratio of alveolar part to basal part was 1:5 in low gonial angle and 2:3 in high gonial angle. Males had significantly taller MS with narrower B point area compared to females (P<0.0001). Retroclined incisors exhibited taller and retroclined alveolar parts (P<0.0001). The shape of MS in Class III skeletal base varied at the alveolar part, basal part or both and it is influenced by gonial angle, incisor inclination and sex. Hence, understanding the shape variation of MS is important to aid orthodontic treatment planning.
IP Indian Journal of Orthodontics and Dentofacial Research
The vertical and horizontal growth influences the height of mandibular ramus and length of the mandibular body. The soft tissue chin thickness, the lower airway space and the chin throat length can vary in different growth patterns and different skeletal patterns. Lateral cephalograms of non-growing patients seeking orthodontic treatment (n=120) were included in the study. The samples were divided into two subgroups based on skeletal pattern (Cl I & Cl II) according to ANB angle and Wit’s appraisal. Further sub divided into four groups based on cephalometric mandibular plane inclination to anterior cranial base (SN-GoGn) and Frankfort’s mandibular plane (FMA) angle in hypodivergent and hyperdivergent patterns. The parameters lower airway space, mandibular body, mandibular ramus, chin thickness and chin throat length were measured. Results showed maximum lower airway space, mandibular body, mandibular ramus, chin thickness, and chin throat length in the hypodivergent skeletal Class I...
The Angle Orthodontist, 2013
Objective: To compare lower incisor dentoalveolar compensation and mandible symphysis morphology among Class I and Class III malocclusion patients with different facial vertical skeletal patterns. Materials and Methods: Lower incisor extrusion and inclination, as well as buccal (LA) and lingual (LP) cortex depth, and mandibular symphysis height (LH) were measured in 107 lateral cephalometric x-rays of adult patients without prior orthodontic treatment. In addition, malocclusion type (Class I or III) and facial vertical skeletal pattern were considered. Through a principal component analysis (PCA) related variables were reduced. Simple regression equation and multivariate analyses of variance were also used. Results: Incisor mandibular plane angle (P < .001) and extrusion (P = .03) values showed significant differences between the sagittal malocclusion groups. Variations in the mandibular plane have a negative correlation with LA (Class I P = .03 and Class III P = .01) and a...
World Journal of Dentistry
Aim: To compare six dentofacial variables among different growth patterns in skeletal class I and class II jaw bases in a lateral cephalogram. Materials and methods: The sample consisted of 120 lateral cephalograms of patients with ages ranging from 18 to 35 years. The sample was divided equally on the basis of ANB angle, Wits appraisal, and beta angle into skeletal class I (group I, n = 60), and class II jaw bases (group II, n = 60). Each group was then further divided into average (SN-MP 28-32°), horizontal (SN-MP <28°), and vertical growth patterns (SN-MP >32°). Hence, there were a total of six groups with 20 cephalograms each. The six parameters: interincisal angle (IIA), intermolar angle (IMA), inclination of symphysis (ISY), antegonial notch depth (AGN), lower anterior facial height (LAFH), and ramus height (RH) were traced, and a comparison was made among different growth patterns in class I and class II jaw bases. Statistical analysis was done using one-way analysis of variance (ANOVA) followed by post hoc Bonferroni test. Results: Ramus height (RH) and AGN show an insignificant difference between class I and class II jaw bases irrespective of growth pattern. LAFH is significantly increased for class II jaw bases, and ISY is more for class I jaw bases for normodivergent and hypodivergent patterns. IIA and IMA are significantly more for class I jaw bases for normodivergent and hypodivergent growth patterns, respectively. Conclusion: There is a suggestive effect of anteroposterior jaw base relationship on the parameters considered in the study which were formerly considered to be influenced only by growth patterns. Clinical significance: From a clinical perspective, in an individual seeking orthodontic treatment, the decision to extract, anchorage preparation, biomechanics applied, and period of retention are dependent on different growth patterns and the anteroposterior relationship of jaw bases which is shown to be influenced by the parameters considered in this study.
The European Journal of Orthodontics, 2005
S UMMARY The aim of this compound cephalometric and arch-width study was to determine any dental and/ or skeletal differences between subjects with Class II division 1 and Class II division 2 malocclusions. The dento-skeletal characteristics of Class II subjects were evaluated using lateral cephalometric radiographs and dental casts of 90 untreated patients. The sample included 46 Class II division 1 patients (19 girls and 27 boys) with a mean age of 15.27 ± 2.48 years, and 44 Class II division 2 patients (27 girls and 17 boys) with a mean age of 15.95 ± 3.25 years. The intermolar, interpremolar and intercanine measurements were carried out on study models. The radiographs were digitized and processed using Dolphin Imaging software. In addition to standard descriptive statistical calculations, an independent samples t-test was carried out in order to compare the two groups. The non-parametric Mann-Whitney U test was utilized for the parameters for the data which were not normally distributed. The only statistically signifi cant difference between the groups for the study model measurements was mandibular intercanine width. The cephalometric results revealed that SNB angle was responsible for the skeletal sagittal difference between the two groups. In addition, the Class II division 1 group had higher vertical proportions and the Class II division 2 group a more concave profi le with a prominent chin. The sagittal skeletal pattern of Class II division 2 subjects was found to be very similar to the Class I skeletal relationship, with no evidence of any mandibular restriction.