Class II D1 malocclusion.docx - Class II D1 malocclusion...

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Class II D1 malocclusionClassificationsClass II Incisor: Lower incisor occludes distal to the upper incisor cingulum plateau, upper incisors proclined or normally inclined with an increased OJ.Class II Buccal: MB cusp of the upper first molar mesial to the MB groove of the lower first molar.Class II Subdivision: one side class I molar relationship and the other is class II MR.Class II Indefinite: One upper central incisor is proclined one is retroclined (Gravely)Class II Intermediate: Incisors are of normal inclination but the OJ is 5-7 mm (Williams and Stephens, 1992).Prevalence (Foster and Day 1974), (Houston 1992)Class I 44%Class II D1 27%Class II D2 17%Class III 3%Indefinite 9% Williams & Stephens, 1992Class II intermediate 10%, Upper incisor are upright and OJ 5-7mmTreatment Need1.IOTNDHC IOTN 5= OJ>9mmDHC IOTN 4= OJ 6-9mmDHC IOTN 3= OJ 3-6 incompetent lipsDHC IOTN 2= 3-6 competent lips.2.Trauma: Todd and Dodd 198545% >9mm & 27% if it is less than 9mm3.Aesthetic 4.Oral Health eg. the palate 5.FunctionEtiologyI.Geneticeffecting the skeletal growth (see the skeletal features), Harris 1969II.Environmental1.Traumato condyle2.Habits, Larsson 19873.DentalfactorsPathological teeth migration forward.4.Softtissue, it is mainly mediated by the underlying skeletal patternLower lip trapping, hyperactive mentalis, and lip incompetence due to short upper lip.

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