The Effect Of Growth Potential On The Deep Bite Correction

Purpose:The purpose of this study was to analyze the skeletal,dental and soft tissue changes produced by orthodontic correction of a deep bite.A comparison was made between the adolescents’ and the adults’ responses in an attempt to observe any differences that accounted for increased stability in terms of skeletal,dental and soft tissue reconstruction in a growing patient.Methods: Records on 30 excessive overbite patients were analyzed before and after treatment.These patients were divided into two equal groups on the basis of their stage of maturational development.The group of "growers" had an average age of 12.8 years,and the group of "nongrowers" averaged 26.6 years in age.Deep bite was corrected by leveling with conventional continuous arch wires.Bite plate,Class II,or vertical elastics were used when indicated..Lateral head films were taken before treatment(T1)and after treatment(T2).All films were analyzed in terms of skeletal changes(FMA,SNA,SNB,ANB,Y angle,Ar-Go-Me,ANS-Me,N-ANS,S-Go/N-Me,ANS-Me/NMe),dental changes(U1-PP,U6-PP,L1-MP,L6-MP,Overbite,U1-LI,U1-SN,IMPA),and soft tissue changes(NLA,Z angle,upper lip-EP,lower lip-EP,Pg-Pg’).Results:(1)Before the treatment(T1),skeletal changes shows that ANS-Me of adults was(61.16±3.11)mm,higher than adolescents’,which was(57.52±4.60)mm(P<0.05).Dental changes shows that the U1-PP,U6-PP and U1-L1 of adults was higher than adolescents’(P<0.05).While adolescents’ upper lip-EP was significantly higher than adults’(P < 0.05).(2)No significant differences was found between adults and adolescents(P<0.05).(3)With the treatment of adolescents(T1-T2),Y angle,ANSMe,ANS-Me/N-Me significantly increased(P<0.05),FMA showed a potential to increase;U1-PP,U6-PP,L6-MP,U1-LI increased,while L1-MP,Overbite and U1-SN decreased(P < 0.05);both upper and lower lip to EP decreased,while Z angle increased(P<0.05).(4)With the treatment of adults(T1-T2),S-Go/N-Me decreased(P<0.05),while ANS-Me showed a potential to increase;L6-MP increased,while U1-PP,L1-MP,Overbite,U1-SN decreased(P<0.05);both upper and lower lip to EP decreased,while NLA increased(P<0.05).(5)Between the two groups,adolescents shows more potential of the ability to reconstruction,with more changes of Y angle,ANS-Me,U6-PP,L6-MP,U1-LI,upper lip to EP,however lower decrease of U1-PP(P<0.05).Conclusions:(1)Skeletal changes: after orthodontic treatment,the mandible growth direction of adolescents had a small amount of clockwise rotation,while the adult group only received little increase in the ANS-Me.Both groups maintained normal bone relationship.(2)Dental changes: adolescents showed more ability to increase molars,however not very ideal in extrusion of incisors.Both groups maintained good relationship of incisors.(3)Soft tissue changes: both groups treated by orthodontic treatment received better profile,upper and lower lips to EP are reduced,the juvenile group decreased more significantly.