Relationship Between The Curve Of Spee And Malocclusion

Objective:By measuring the curve of Spee(COS)andvarious indicators of malocclusion,the thesis was used to investigate the gender difference of the COS and the differences of the COS under Angle's classification and analyze the correlation between the COS and craniofacial morphology.It is hoped to provide theoretical basis for leveling the COS in orthodontic clinical works.Materials and methods:Lateral cephalograms and dental models of 200 untreated patients in our hospital were selected randomly.All patients fulfilled the following inclusion criteria:all teeth present included the second molars;no previous orthodontic treatment;no severe dental and periodontal diseases;no severe craniofacial deformity such as cleft lip and palate;no significant medical history.According to Angle's classification,the patients were divided into Class?group,Class?group and Class?group.The patient models were scanned by the Danish 3Shape R700 scanner,rebuilt by 3Shape Scanit Orthodontics~TMM software,and measured lateral cephalograms of the patients by The Geometer's Sketchpad.The results which recorded in SPSS 19.0software were used for analyzing the differences between left side and right side,different genders and different Angle's classifications of the COS.The results were also used for analyzing the correlation between the curve of Spee and craniofacial morphology.Results:1.According to the Mann-Whitney U test,different sex groups showed that the curve of Spee was not affected by sex(P>0.05).2.According to paired sample Wilcoxon rank sum test,both sides of the COS showed:Both sides of the curve of Spee had statistically significant differences in Class?(P<0.01),and there was no statistically significant difference between Angle class I and Angle Class III(P>0.05).3.The depth of the COS was significantly different among different Angle's classifications in which Class?was obviously higher than Class?and Class?,but there was no statistical significance between Class?and Class?(P>0.05).4.ByanalyzingtheCOSandvariousmeasurementindicatorsof malocclusion:overbite(r=0.456),overjet(r=0.385),ANB(r=0.213),L6-MP(r=0.201),L7-MP(r=0.236),ODI(r=0.243)werepositivelycorrelatedwiththeCOS.L1-MP(r=-0.172),SNA(r=-0.203),SNB(r=-0.293),APDI(r=-0.389)were negatively correlated with the COS.Conclusions:1.Different sex groups showed that the curve of Spee was not affected by sex.2.Both sides of the curve of Spee had statistically significant differences in Class?(P<0.01),and there was no statistically significant difference between Angle class I and Angle Class III(P>0.05).3.The depth of the COS was significantly different among different Angle's classifications in which Class?was obviously higher than Class?and Class?(P<0.01),but there was no statistical significance between Class?and Class?(P>0.05).4.There was a certain correlation between the cos and craniofacial morphology.The COS and various measurement indicators ofmalocclusion:overbite(r=0.456),overjet(r=0.385),ANB(r=0.213),L6-MP(r=0.201),L7-MP(r=0.236),ODI(r=0.243)werepositivelycorrelatedwiththeCOS.L1-MP(r=-0.172),SNA(r=-0.203),SNB(r=-0.293),APDI(r=-0.389)were negatively correlated with the COS.Among all the indicators,APDI and overbite had great influence.