Page 133 - FINAL COMPENDIUM 2020-2021 27.2.2022

GEOMETRIC MORPHOMETRIC ANALYSIS (GMA) OF MANDIBULAR SYMPHYSIS IN CLASS
III SKELETAL BASE PATIENTS IN DIFFERENT AGE

Teo KF, Murshida MN, Alizae Marny SM, Helmi HP
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 <1o) and lower incisor angle (<99o) were included. The sample was divided into
adolescence, emerging adulthood, and adulthood based on gonial angle. Nine-landmarks
with x and y coordinates were identified on mandibular symphysis. Procrustes anova and
canonical variate analysis was used to compare mean differences for age groups. Results:
In high gonial angle group, adults had significantly narrower alveolar and basal part of MS
(p=0.003, 10000 permutation test) while emerging adults had significantly narrower
alveolar part of MS (p=0.01, 10000 permutation test) compared to adolescents. In average
gonial angle group, adults have significantly narrower alveolar and basal part of
mandibular symphysis compared to emerging adults (p=0.007, 10000 permutation test)
and adolescents (p<0.0001, 10000 permutation test). Low gonial angle groups showed
wider and shorter mandibular symphysis for all age groups. Conclusion: The MS shape can
be affected by age groups where significant MS shape variation observed between
adolescents, emerging adults, and adults. Hence, understanding the shape variation of
mandibular symphysis especially in adults with high gonial angle is important during
orthodontic treatment planning to avoid unwanted complications.

Keywords: Geometric Morphometric Analysis, Mandibular symphysis, Age, Class III, Gonial angle,
Shape
Poster presentation at the 19 Annual Scientific Meeting Malaysian Section International Association of Dental Research
th
on 10th October 2020 at the Accappella Suite Hotel, Shah Alam, Malaysia
Published in International Journal of Dentistry and Oral Science, 2021;08(06): 2716-2720

Dr Teo Kui Fei
Orthodontic Unit
Jalan Sultan Mahmud Dental Clinic
Kuala Terengganu
Terengganu

Dr Murshida Marizan Nor
Dr Alizae Marny Fadzlin Syed Mohamed
Discipline of Orthodontics
Centre for Family Oral Health
Faculty of Dentistry
Universiti Kebangsaan Malaysia

Dr Helmi Mohd Hadi Pritam
School of Health Sciences
Universiti Sains Malaysia

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