A Study Of The Mandibular Characteristic In Genetic Angle Class â…¢ Malocclusion

Objective:To evaluate the mandibular characteristic of Classâ…¢malocclusion and analysis the parent-offspring similarity in Classâ…¢malocclusion,find the relationship of each other.To study the genetic feature of Classâ…¢malocclusion and analysis the clinical implication.Materials and methods1 The craniofacial morphology of samples derivide from the orthodontic Department of Tianjin Stomatological Hospital from Jan.1 2007 to Dec.31 2008. The study group comprised 88 pre-treatment Lateral Cephalo-metric records of Classâ…¢patients(44 female,44 male)aging from 7 to 28 years old,compared to 100 individual normal occlusion standerd(50 female,50 male).The Classâ…¢patients was divided into two groups by cervical bone age:the developing group (22 female,22 male) and the developed group(22 female,22 male).Comparison of mandibular cephalometric measurements was made not only between Classâ…¢group and individual normal occlusion sample,but among classsification in Class group according to skeletal maturation.2 The craniofacial morphology of samples derivide from the orthodontic Department of Tianjin Stomatological Hospital from Jan.1 2007 to Dec.31 2008. The sample examined included 88 Classâ…¢patients(44 female,44 male)aging from 7 to 28 years old and their parents including 85 fathers and 86 mothers. Parent-offspring multicorrelation analysis was conducted individually on 69 cephalomtric indexes of mandible.Results1 There were 16 mandibular characteristic measurements in 69 relationships: DBNFH,DPogNFH,SL,Y-axis,N-Go-Me,ANB,Ar-Go-Me,A-Bplane, SNA+NSAr,L1-NB,L1-MP,Sn-Ns-Sb,Wits,Ns-TN-TC,(TUL-SnTC)-(TLL-SnTC),TLL-Sb-TC;2 By stepwise discrimination analysis,6 discrimination functions selected: (TUL-SnTC)-(TLL-SnTC),ANB,Sn-Ns-Sb,Wits,L1-MP,SNA+NSAr.3 The parent-offspring correlation was significant.Skeletal measurements with parent-offspring correlation were more than dental and soft tissue measurements. In skeleton,the correlation between maternal parents and the boyes is the strongest;in dental area,the parent-offspring correlation were weaker,the correlation between maternal parents and the offsprings is a little stronger;in soft tissue,the correlation between faternal parents and the offsprings is a little stronger.4 There were 16 measurements with no parent-offspring correlation in 69relationships5 Charateristic measurements had srtonger similarity between parents and offsprings than others.Conclusin1 There were 16 mandibular characteristic measurements and 6 discrimination functions in 69 relationships.2 The parent-offspring correlation was significant.The intensity of correlation between parents of different sexes and their offsprings varies on the basis of different studied areas.There were 16 measurements with no parent-offspring correlation in 69relationships3 Charateristic measurements had srtonger similarity between parents and offsprings than others.Maybe there were some special genetic features in Classâ…¢malocclusion.