The Association of Tongue Posture with Dentoalveolar Maxillary and Mandibular Morphology in Adults with Class II division 2 Malocclusion

Abstract

Objective: This study aims to evaluate the relationship between the tongue posture and the dentoalveolar maxillary and mandibular morphology in adults with Angle's Class II division2 Malocclusion comparing with adults with Angle's class I normal occlusion.

Materials and methods: The sample consisted of 60 adults with age range (18-25) years with mean (21.33 + 2.88) years, sample consisted of two groups, the first one contains 30 adults with Angle's Class II division2 Malocclusion, skeletal class II relationship and horizontal growth pattern, the second group contains 30 adults with Angle's Class I normal occlusion, skeletal class I relationship and normal growth pattern. The measurements were made on the lateral cephalograms which are taken before treatment to assess tongue posture, also dimensions were measured between upper and lower canines and first molars and the anterior length of upper and lower dental arches on dental casts which are taken before treatment. Independent sample T- student was made to compare the variables measured on the lateral cephalograms and dental casts, also Pearson Correlation was made between tongue posture and inter-canine cusp and gingiva ratios and inter-molar cusp and gingiva ratios and the anterior length of upper and lower dental arches.

Results: D1, D2،D3, TGL are statistically significant less in adults with Angle's Class II division2 malocclusion, whereas D4 ، D5 ،D6 ، D7, TGH are statistically significant greater in adults with Angle's Class II division2 malocclusion. The inter-canine cusp and gingiva widths and inter-molar cusp and gingiva widths in the maxillary and the mandible, and also the anterior length of upper and lower dental arches are statistically significant less in adults with Class II division2 malocclusion (P< 0.05). The correlation between D1, D2،D3 ، D4 ، D5 ،D6 ، D7، TGH and TGL and inter-canine cusp and gingiva ratios and inter-molar cusp and gingiva ratios and the anterior length of upper and lower dental arches, the correlation is weak in both groups.

Conclusions: Tongue takes posterior position, and the posterior portion of the tongue dorsum takes superior position whereas the anterior portion of tongue dorsum takes inferior position in the adults with Angle's Class II division2 malocclusion, skeletal class II relationship and horizontal growth pattern. The means of inter-canine cusp and gingiva widths and inter-molar cusp and gingiva widths and the anterior length of upper and lower dental arches are less in adults with Angle's Class II division2 malocclusion comparing with adults with Angle's class I normal occlusion. There is a weak correlation between tongue posture and inter-canine cusp and gingiva ratios and inter-molar cusp and gingiva ratios and the anterior length of upper and lower dental arches in both groups.

Keywords: Class II division2 Malocclusion – tongue posture –  lateral cephalogram- dental casts