A Clinical Study For The Expressions Of IL-1β And TNF-α In Gingival Crevicular Fluid Of Orthodontic Patients Treated By Self-ligating Bracket Appliance

Objective: The purpose of this study is to compare and assess the changeof interleukin1β(IL-1β)and tumor necrosis factor-α(TNF-α)in the gingivalcrevicular fluid (GCF) of patients treated by the self-ligating bracket or theconventional bracket before and after orthodontic appliance wearing usingenzyme linked immunosorbent assay (ELISA), and to analyze the effect ofdifferent bracket to the oral environment. This study also attempt todemonstrate that the self-ligating bracket is more helpful to the periodontalhealth and provide orthodontists with theoretical basis for choosingorthodontic appliance.Methods:38patients (20males and18females, mean age13.7±1.26years) underwent orthodontic treatment in the Department of Orthodontics ofHebei Medical University between January to November2013were involvedin this study. The including categories were: healthy and nonsmoking, femalepatients were non-pregnant and non-lactating, no dental caries or with treatedtooth decay, healthy periodontal tissue and normal probing depth less than3mm, no oral mucosal lesion, no obvious oral bad habits, no oral treatment ofantimicrobial drugs or steroids during six months before experiment. All the38patients were randomly divided into two groups. One group (group A)underwent orthodontic treatment by conventional bracket, the other (group B)applied the self-ligating bracket. Two hours postprandial GCF was collectedand the concentration of IL-1β and TNF-α was measured at different timepoints: before orthodontic treatment (T0)、four weeks (T1)、eight weeks (T2)and12weeks after the placement of orthodontic appliances. Two hourspostprandial, collecting GCF of patient. Then the micro-centrifuge tube wasimmediately wrapped by aluminum foil and stored at-70℃until needed. Statistical analysis was performed using SPSS13.0at a preset alpha levelof0.05and the statistical significance was defined as P <0.05. Beforeorthodontic treatment two-sample test was used to compare the GCF volumeand the concentration of IL-1β and TNF-α between the conventional bracketgroup and the Self-ligating bracket group. The analysis of variance (ANVOA)was used to analyze the differences of the GCF volume and the concentrationof IL-1β and TNF-α between the different time point of orthodontic treatment.Results:1. In T0of orthodontic treatment, there were no significant differencesbetween the conventional bracket group and the Self-ligating bracket groupfor the GCF volume (F=0.043; P=0.837) and the concentration of IL-1β andTNF-α (F=0.030; P=0.864).2. The amount of GCF from Patients wearing the two fixed orthodonticappliances both had a trend of increasing in a certain extent after bondingbrackets at4、8、and12weeks, the difference was statistically significant(P<0.05). The concentration increased with prolonged wearing time oforthodontic appliance, and the GCF volume between every two time pointswas also significantly increased. Between the patients with traditional bracketant that with self-ligating bracket, a significant difference was also seen for theGCF volume when analyzed by ANOVA (F=10.235; P=0.003).3. Before wearing the fixed orthodontic appliances, few of IL-1βandTNF-α was found in the gingival crevicular fluid. Concentration of IL-1β andTNF-α after bonding brackets increased firstly and then gradually decreased，but was still significantly higher than normal untreated healthy teeth. Therewas also a statistically significant difference of both IL-1β level (F=10.004;P=0.003<0.05) and TNF-α level (F=6.517; P=0.015<0.05) between thetraditional bracket patients and the self-ligating bracket ones.Conclusion:1. Although a temporary elevation of GCF volume and theconcentration of IL-1β and TNF-α in GCF was resulted from the using offixed orthodontic appliance, in this regard we infer that any fixed appliance may cause varying degrees of periodontal tissue inflammation.2. Compared to the traditional bracket appliance, the self-ligating bracketbenefit to the maintaining of oral hygiene which is critical for the periodontalhealth, This provides a theoretical guidance for clinical orthodontic patients tochoose a fixed appliance which is more conducive to periodontal health.