Francisconi Luciana Fávaro, Graeff Márcia Sirlene Zardin, Martins Leandro de Moura, Franco Eduardo Batista, Mondelli Rafael Francisco Lia, Francisconi Paulo Afonso Silveira, Pereira José Carlos
Department of Operative Dentistry, Endodontics and Dental Materials, Bauru School of Dentistry, University of São Paulo, Bauru, São Paulo, Brazil.
J Am Dent Assoc. 2009 Oct;140(10):1275-82. doi: 10.14219/jada.archive.2009.0051.
Researchers have proposed the restoration of abfraction lesions, but limited information is available about the effects of occlusal loading on the margins of such restorations. Because abfraction is a well-recognized problem, the authors conducted a study to assess the effects of occlusal loading on the margins of cervical restorations.
The authors prepared 40 wedge-shaped cavities in extracted premolars and restored them with a resin-based composite. They subjected specimens to occlusal loading (150 newtons, 10(6) cycles) on the buccal cusp, on the central fossa or on the lingual cusp, and they stored the control group specimens in deionized water. The authors used fluorescein to delimit marginal defects and evaluated the defects by using laser scanning confocal microscopy.
Results of chi2 and Kruskal-Wallis tests (P < .05) showed that specimens subjected to occlusal loading had a higher percentage of marginal gaps (53.3 percent) than did the control specimens (10.0 percent). There were no differences between groups in marginal defect formation or in defect location, length or width.
Occlusal loading led to a significant increase in gap formation at the margins of cervical resin-based composite restorations.
The clinician cannot underestimate the effects of occlusal loading when restoring teeth with cervical wedge-shaped lesions. If occlusal loading is the main factor contributing to lesion formation, the clinician should identify and treat it before placing the restoration or otherwise run the risk that the restorative treatment will fail because of marginal gap formation.
研究人员已提出修复磨损性病变，但关于咬合负荷对此类修复体边缘的影响，现有信息有限。由于磨损是一个公认的问题，作者开展了一项研究，以评估咬合负荷对颈部修复体边缘的影响。
作者在拔除的前磨牙上制备了40个楔形洞，并使用树脂基复合材料进行修复。他们让标本在颊尖、中央窝或舌尖承受咬合负荷（150牛顿，10⁶次循环），并将对照组标本保存在去离子水中。作者使用荧光素划定边缘缺陷，并通过激光扫描共聚焦显微镜评估缺陷。
卡方检验和克鲁斯卡尔 - 沃利斯检验结果（P <.05）表明，承受咬合负荷的标本边缘间隙百分比（53.3%）高于对照标本（10.0%）。各组之间在边缘缺陷形成、缺陷位置、长度或宽度方面没有差异。
咬合负荷导致颈部树脂基复合材料修复体边缘间隙形成显著增加。
临床医生在用颈部楔形病变修复牙齿时，不能低估咬合负荷的影响。如果咬合负荷是导致病变形成的主要因素，临床医生应在进行修复之前识别并处理它，否则可能会冒修复治疗因边缘间隙形成而失败的风险。
