Clinical Study Of Contrast Of PASS Technique And Conventional MBT Technique On The Changes Of The Hard Tissue Before And After The Treatment Of Class ? Division 1 Malocculsion

Objective: To observe the changes of the hard-tissue morphplogy and the teeth before and after the treatment with two different techniques and methods in class ? division 1 maloccusion,and to provide clinical treatment with some guidance.Methods: The samples consisted of 40 cases(19 males,21 females)randomly selected from the Stomatological Center at The Fist Affiliated Hospital of Wannan Medical College,from August 2015 to August 2016.The patients were diagnosed with class ? division 1 maloccusion after growth development peak with the average-angle ficial type.Their age range from 12 to 17 years old,with an average of 13.5±1.34 years.The cases were divided into four groups according to the two different techniques and methods.There are non-extraction treatment with MBT technique group(A1),extraction treatment with MBT technique group(A2),non-extraction treatment with PASS technique group(B1),extraction treatment with PASS technique group(B2).The cephalometric analysis was performed before and after treatment.All the lateral cephalometric were drawn by the same person under the negatoscope within two weeks.The measured value was repeated three times,then the average figures would be available.The paired t-test and independent t-test were used to analyze the results between the intra group and inter group.Results: Compare the measured values before and after treatment in the four groups,the value of SNA,ANB,NA-PA,U1-NA were all decreased,the value of SNB,U1-L1 were both increased.ANB in A1 and B1 group,NA-PA in A2 group,U1-NA and U1-SN in A1 group,L1-NB in A2 and B2 group,L1-MP and U1-L1 in B2 group were statistically significant(P<0.05).ANB in A2 and B2 group,NA-PA in B2 group,L1-MP and U1-L1 in A2 group were notable statistically significant(P<0.01).Compare the two groups between the extraction treatment group and the non-extraction treatment group(A1 vs A2,B1 vs B2).We can see that the value of L1-NB?L1-NB(mm)?L1-MP?Y axis were increased in the non-extraction treatment group,but decreased in the extraction treatment group.The value of MP-SN,FH-MP were increased in the A1 ?A2 and B1 groups,but decreased in the B2 group.The changes of ANB?L1-NB?Y axis between the A1 vs A2 groups had statistically significant(P<0.05),L1-MP and L1-NB(mm)had notable statistically significant(P<0.01).Compare the two groups between the PASS technique group and the MBT technique group(A1 vs B1,A2 vs B2).The changes in the two groups were basically the same as the value of SNA,SNB,ANB,MP-SN,FH-SN and the angle of the upper and lower teeth.The range of change is slightly different,but there is no statistical significance.The changes of MP-SN and FH-MP are the opposite in the extraction treatment group,which was increased in the MBT technique group but decreased in the PASS technique group.In particular,it had notable statistically significant in he value of MP-SN(P<0.01).Conclusion:1.The two orthodontic techniques and two orthodontic methods are both good for the treatment of the class ? division 1 maloccusion.2.There is no obvious difference in the non-extraction treatment group between the MBT technique and the PASS technique.But the PASS technique can better control the mandibular plane than the MBT technique in the extraction treatment group.And in the treatment of extraction,there is a posterior movement of tooth.,especially for the protruding facial profile.