后牙邻面悬突的X线负片调查

Retrospective Investigation on Overhangs of Posterior Teeth in Dental Radiographs

随机取出牙片６９６８张，从中挑出牙片质量保存完好和牙片上的牙齿位置不重叠的且有银汞合金充填Ⅱ类洞的牙片１００６张，其中充填体１１１６个．观察充填体的邻面有无悬突和充填不足．银汞合金充填Ⅱ类洞的悬突发生率为６０．７５％±１．４６％，银汞合金充填Ⅱ类洞的充填不足发生率为２．６０％±０．４７％．在邻面１／３、中１／３、颈１／３和颈下，银汞合金充填Ⅱ类洞悬突发生率差异非常显著（Ｐ＜０．００１）．在不同象限银汞合金充填Ⅱ类洞悬突发生率差异不显著（Ｐ＞０．０５）．

dental radiographs have been taken from our department for recent ten years,among which thereare 1006 radiographs of class Ⅱ amalgam restorations. These radiographs are clear enough to read,in whichteeth were not overlapped each other and contained 1116 class Ⅱ amalgam restorations. It is investigatedwhether or not the overhangs and filling deficiency on the proximal contour of class Ⅱ amalgam restorationsexisted. The incidence of overhangs is 60. 75% ± 1. 46 % on proximal contour of class Ⅱ amalgam restorationsand the incidence of filling deficiency is 2. 60% ± 0. 47%. It is highly significant difference (P<0. 001 ) ofoverhangs among the different positions of teeth,i. e.,occlusal third,middle third,cervical third,and subcervicus. Overhangs are not significant difference (P>0. 05) in the different quadrants i. e.,upper right area,upper left area,low right area,and low left area.