Three-dimensional Analysis To Compare Anchorage Of The Nance Arch And TPA After Canine Retraction

ObjectiveAfter leveling and alignment the following stage of treatment is to closeextraction space.To evaluate during canine retraction whether TPA(thetranspalatal arch) or a Nance arch was most effective for prevention the upperfirst permanent molars in sagitta direction,horizontal direction,verticaldirection,distal tipping directions and mesio-palatal rotation. The investigate wasexaming the discomfort differences between TPA or the Nance arch. The aim ofthis trail was to provide useful clinical evidence for orthodontists.MethodsApproval for this study was obtained from department of orthodontic ofstomatology of PLA Second Artillery General Hospital during2010-2011. Fortypatients were recruited and patients who fulfilled the inclusion criteria wererandomly allocated to each group.Enrollment criteria:1. All patients aged18-22，permanent dentition, exclusion of other toothdefects2. Class I or Class II devision1maloclussion,moderate crowding,slightprotrusion profile3. Extraction of upper and lower first premolars,extraction of four thirdmalors 4. All of them were completed the two-step space closed thrapy,moderateanchorageAll patients were equipped with edgewise appliance(0.022-inchRoth,ORJ,HangZhou). After leveling and aligning phase of treatment,upperpalatal arches are banded with Nance arch or the transpalatal arch. All subjectswere controlled once a month.In a split-mouth design,precalibrated elastomericchain delivering a force of100g were used to distalize the canine with0.018inch stainless steel archwire. Upper insicors were tied with a continuous ligatureusing the "figure8" method. Data were collected until space closed.Lateral cephalograpms and study casts were collected before treatmentand the clinical end point. The index of measurements are as follows,U6-PP,U6-SN,U1-SN, MP-SN, Ars-Me/N-Me and prevention of molar mesialdrift,stable width and distal tipping.Statistical analysis was performed usingsoftware package Spss17.0.All of the work was done by one observer andtaken the average of three times for statistical analysis.The patients recorded their discomfort scores using a questionnaire oforthodontic pain after banded with TPA or a Nance arch. In addition,orthodontistfilled the rest of the questionnaire after check the palatal mucosa and gingivalof the objects each referral.The survey was analyzed which of the palatal archwas discomfort.ResultsThere was no statistically significant difference between the groups for age.In addition, there was no statistically significant difference in gender betweenthe two palatal arch groups.No significant differences between the transpalatal arch and Nance archgroups in terms of prevention of mesial drift,stable width,vertical displacementand distal tipping (P>0.05).However,there was a statistically significantdifference in the amout of molar rotation between the arch types(P<0.05).Both gourp’s discomfort and adaptation period have no difference(P>0.05).Gingival inflammation of the bilateral maxillary permanentfirst molar have no difference in the two groups.Inflammation of anterior palatalmucosa of patients who fixed with TPA is significant difference with who with theNance arch(P<0.05).ConclusionsThere were no statistically significant differences between the transpalatalarch and Nance arch groups in3D directions.In contrast, there was astatistically difference between the two groups in terms of prevention ofmesio-palatal rotation in this trial.Patients who use the TPA are significantcomfort than who use the Nance arch.