Zeng B J, Guo Y, Yu R Y
Department of Prosthodontics, Beijing Stomatological Hospital & School of Stomatology, Capital Medical University, Beijing 100050, China.
Department of Stomatology, Beijing Shijitan Hospital, Capital Medical University, Beijing 100038, China.
Beijing Da Xue Xue Bao Yi Xue Ban. 2018 Jun 18;50(3):553-559.
To evaluate the effect of the vacuum-formed retainer on preventing the proximal contact loss between the implant supported crown and its adjacent natural teeth.
Forty-six posterior implant crowns in the mandible including 92 interproximal contacts in 46 patients (19 men, 27 women) aged from 25 to 66 years were included. The participants in experimental group (22 cases) were vacuum-formed retainers at night, while participants in control group (24 cases) only received routine examination. The two groups were not different in age, gender, the time interval of the tooth loss and tooth position at baseline. Mesial and distal proximal contact tightness was measured using the orthodontic dynamometer and metallic articulating film immediately after crown delivery, and 1-month, 3-month, 6-month, and 1-year follow-up respectively. The articulating film was inserted interdentally from the occlusal direction, and then it was slowly removed in the buccallingual direction by the dynamometer. Increasing the number of films (N) piece by piece until the frictional force (F) was great than 0, and the number of films (N) was recorded. At each follow-up, proximal contact between implant crown and its adjacent teeth was considered to be loss if the number of films (N) used at immediate crown delivery passed without frictional force (F=0). Besides, the periodontal conditions [scored according to the probing depth (PD), bleeding index (BI), mobility (M)] and complaint of food impaction were recorded. The mesial and distal proximal contact loss rates were compared between the two groups at different times. Chi-square test or Fisher's exact test was used for statistical analysis.
The proximal contact loss rate on the mesial surface of the implant supported crown continuously increased over the follow-up periods. At the end of the 1-, 3-, and 6-month follow ups, 18.2%, 22.7% and 27.3% were identified for the contact loss rates on the mesial surface of the implant supported crown in the experimental group, respectively. Meanwhile in control group, the rates were 20.8%, 37.5% and 45.8%. No significant differences were observed at the end of the 1-, 3-, and 6-month follow ups(1-month: χ=0.000, P=1.000; 3-month: χ=1.183, P=0.277; 6-month: χ=1.697, P=0.193). The proximal contact loss rate on the mesial surface in control group (62.5%) was significantly higher than that in the experimental group (31.8%, χ=4.330, P=0.037) at the end of the 1-year follow-up. However, no statistical difference was found on the distal surfaces between the two groups during the whole follow-up periods. The first open contact was noted 1 month after crown insertion.
By wearing vacuum-formed retainer for one year, the incidence of open contacts between the posterior implant prostheses and mesial adjacent teeth in the mandible has been reduced.
评估真空压膜保持器对防止种植体支持冠与其相邻天然牙之间邻面接触丧失的效果。
纳入46例下颌后牙种植冠，共92个邻面接触点，患者年龄25至66岁，其中男性19例，女性27例。试验组（22例）患者夜间佩戴真空压膜保持器，对照组（24例）仅接受常规检查。两组患者在年龄、性别、失牙时间间隔和基线牙位方面无差异。在冠修复后即刻、1个月、3个月、6个月和1年随访时，使用正畸测力计和金属咬合纸测量近中及远中邻面接触紧密度。将咬合纸从咬合方向插入牙间隙，然后用测力计沿颊舌方向缓慢取出。逐片增加咬合纸数量（N），直至摩擦力（F）大于0，并记录咬合纸数量（N）。在每次随访时，如果冠修复后即刻使用的咬合纸数量无摩擦力通过（F = 0），则认为种植冠与其相邻牙之间的邻面接触丧失。此外，记录牙周状况[根据探诊深度（PD）、出血指数（BI）、松动度（M）评分]和食物嵌塞主诉。比较两组在不同时间的近中及远中邻面接触丧失率。采用卡方检验或Fisher精确检验进行统计学分析。
在随访期间，种植体支持冠近中面的邻面接触丧失率持续增加。试验组在1个月、3个月和6个月随访结束时，种植体支持冠近中面的接触丧失率分别为18.2%、22.7%和27.3%。同时，对照组的相应比率分别为20.8%、37.5%和45.8%。在1个月、3个月和6个月随访结束时，未观察到显著差异（1个月：χ=0.000，P = 1.000；3个月：χ=1.183，P = 0.277；6个月：χ=1.697，P = 0.193）。在1年随访结束时，对照组近中面的邻面接触丧失率（62.5%）显著高于试验组（31.8%，χ=4.330，P = 0.037）。然而，在整个随访期间，两组远中面未发现统计学差异。在冠修复后1个月首次发现开放性接触。
佩戴真空压膜保持器1年可降低下颌后牙种植修复体与近中相邻牙之间开放性接触的发生率。
