Assistant Professor, Prosthodontics Department, School of Dentistry, Azad Islamic University, Tehran, Iran.
Private practice, Tehran, Iran.
J Prosthet Dent. 2020 Apr;123(4):618-621. doi: 10.1016/j.prosdent.2019.05.001. Epub 2019 Jul 26.
Screw loosening is still among the most important complications of dental implants. Identifying effective factors in screw loosening plays an important role in preventing this problem.
The purpose of this in vitro study was to assess the effect of fluid contamination on the reverse torque values (RTVs) of abutment screws at implant-abutment connections.
Five groups (9 specimens in each group) of implants were mounted in acrylic resin. Four groups of fixture screw holes were contaminated with chlorhexidine (CG), saliva (SG), blood (BG), or fluoride (FG), and a fifth group served as a control with no contamination (NC). Abutment screws were tightened by using a digital torque meter. The RTVs were recorded after thermocycling. Data were analyzed by 1-way ANOVA and the Tukey honestly significant difference test (α=.05).
RTVs were lower in SG (13.65 ±0.91 Ncm) than NC (16.55 ±1.82 Ncm), while the values were significantly higher in CG (19.74 ±1.79 Ncm) than NC. No statistically significant difference was reported in BG (16.30 ±1.66 Ncm) and FG (15.92 ±1.82 Ncm) compared with the control group.
RTVs were significantly reduced by saliva contamination in comparison with those of other groups. The highest RTVs were detected in CG.
螺丝松动仍然是牙科种植体最重要的并发症之一。确定螺丝松动的有效因素对于预防该问题起着重要作用。
本体外研究的目的是评估流体污染对种植体-基台连接中基台螺丝反向扭矩值（RTV）的影响。
将 5 组（每组 9 个样本）种植体安装在丙烯酸树脂中。将四组夹具螺丝孔分别用洗必泰（CG）、唾液（SG）、血液（BG）或氟化物（FG）污染，第五组作为无污染对照（NC）。使用数字扭矩计拧紧基台螺丝。热循环后记录 RTV。采用单因素方差分析和 Tukey Honestly Significant Difference 检验（α=.05）对数据进行分析。
SG 组的 RTV （13.65 ±0.91 Ncm）低于 NC 组（16.55 ±1.82 Ncm），而 CG 组的 RTV （19.74 ±1.79 Ncm）明显高于 NC 组。与对照组相比，BG 组（16.30 ±1.66 Ncm）和 FG 组（15.92 ±1.82 Ncm）的 RTV 无统计学差异。
与其他组相比，唾液污染显著降低了 RTV。CG 组的 RTV 最高。
