Comparison of multistranded wire and fiber-reinforced composite retainers effects on periodontium: A randomized clinical trial

ABSTRACT Introduction: Fixed orthodontic retainers are very important for treatment stability; however, adverse effects on the health of periodontium can be caused as a result of deposition of plaque and calculus. Objectives: To compare and determine the effects of two mandibular fixed lingual retainers on the periodontal status, and to test the null hypothesis that there would be no significant difference on the periodontium health between the patients using fiber-reinforced composite (FRC) or multistranded wire (MSW) fixed retainers. Methods: A total of 60 subjects were recruited, out of which 6 were excluded and 2 dropped out during the study. Hence, 52 subjects with mean age of 21.5 ± 3.6 years were included in the study. The sample was composed by 8 males (15.4%) and 44 females (84.6%). The participants were randomly divided into two groups: Group 1 received fiber-reinforced composite retainer, while Group 2 received multistranded wire retainer. After insertion, plaque index, calculus index, gingival index and bleeding on probing were compared, after three months (T1), six months (T2), nine months (T3) and twelve months (T4), using Mann-Whitney test with p-value ≤ 0.05 as significant. Results: It could be seen that the health of periodontium deteriorated with the passage of time from T1 to T4 in both group of retainers. However, no statistically significant differences were found between the two groups (p> 0.05). Conclusion: The results of the study indicate that there was no significant difference on the health of periodontium between the patients with FRC and MSW fixed retainers, hence, the null hypothesis was accepted.

摘要
引言：固定正畸保持器对治疗稳定性具有重要意义，但菌斑与牙结石的沉积可对牙周组织健康产生不良影响。
研究目的：比较并评估两种下颌固定舌侧保持器对牙周状态的影响，检验零假设：使用纤维增强复合材料（FRC）固定保持器与多股丝（MSW）固定保持器的患者，其牙周健康状况无显著差异。
研究方法：本研究共招募60名受试者，其中6名被排除，2名在研究期间脱落，最终纳入52名受试者，平均年龄为21.5±3.6岁。样本包含男性8名（15.4%）、女性44名（84.6%）。将受试者随机分为两组：第1组佩戴纤维增强复合材料保持器，第2组佩戴多股丝保持器。分别在佩戴后3个月（T1）、6个月（T2）、9个月（T3）及12个月（T4）时，比较两组的菌斑指数、牙结石指数、牙龈指数及探诊出血情况，采用曼-惠特尼检验，以p值≤0.05为差异具有统计学意义。
研究结果：结果显示，两组患者的牙周健康状况均随时间从T1至T4逐渐恶化，但两组间未发现统计学显著差异（p>0.05）。
研究结论：本研究结果表明，使用纤维增强复合材料与多股丝固定保持器的患者，其牙周健康状况无显著差异，因此接受原零假设。