An Evaluation Of The Effect Of Different Orthodontic Retainers On The Periodontal Tissue

Objetives:Evaluation the periodontal status wearing different orthodontics retainers toprovide evidences for clinical choice of suitable retainers.Methods:Sixty-three subjects were allocated to four different groups. Group1consisted of20subjects without orthodontic retainers, Group2consisted of15subjects wearingHawley retainers, Group3consisted of15subjects wearing lingual fixed retainers,Group4consisted of13subjects wearing vacuum-formed retainers. All subjectsaccepted ultrasonic scaler after completing a questionnaire, which about the oralhealth behavior and habits. Gingival crevicular fluid(GCF) collection and periodontalhealth assessment were carried out at baseline(T1), and1weeks(T2),12weeks(T3) afterultrasonic scaling. The periodontal health assessment include gingival index(GI) andplaque index(PLI). The quantity of GCF was determined by weighing beforedetermination activity of aspartate aminotransferase(AST) in GCF by automaticbiochemistry analyzer and evaluating the concentration of matrixmetalloproteinase-9(MMP-9) in GCF by enzyme linked immunosorbentassay(ELISA). All tests were carried out by SPSS16.0.Significance was set at the5%level.Results:1. PLI: It was significantly higher in lingual fixed retainers. But the differencesbetween Hawley retainers, vacuum-formed retainers and control group were notstatistically significant.2. GI: Significant differences were noted between retainers group and controlgroup, removable retainers and lingual fixed retainers,whereas no statisticallysignificant result was observed between two types of removable retainers. 3. GI, The Concentration of MMP-9: The retainers group were significantlyhigher than the control group. Besides,the lingual fixed retainers was significantlyhigher than removable retainer group, vacuum-formed retainer group wassignificantly higher than that in Hawley group.4.The Activity of AST: Significant difference was noted between lingual fixedretainers and control group, whereas no significant differences were observed betweenHawley retainers, vacuum-formed retainers and control group.Conclusions:The orthodontic retainers have adverse effect on periodontal health, leading tothe increase of PLI, GI, GCF, MMP-9concentration and AST activity. The lingualfixed retainers show the greatest effect, while Hawley retainers have the minimumeffect.