Analysis of enamel and material wear by digital microscope: an in-vitro study

Abstract: The objective of the study was to analyze the surface area (SA) of the wear caused by simulated chewing on human enamel and opposing restorative material, namely: composite resin (CR), porcelain fused to metal (PFM), lithium disilicate (LD), or monolithic zirconia (MZr). Forty-eight premolars were selected as enamel specimens and divided randomly into 4 groups (n = 48; n =12) used as antagonists in chewing simulation (250,000 loading cycles) against one of the four selected test materials. Enamel and material specimens were scanned and evaluated under digital microscope, and wear SA (mm2) were recorded. Descriptive statistics, paired t-test, one-way ANOVA, and post-hoc Tukey-HSD tests were used for statistics (p < 0.05). The smallest and largest SA were exhibited by enamel against LD (0.80 mm2) and PFM (1.74 mm2), respectively. PFM (3.48 mm2) showed the largest SA and CR (2.28 mm2) showed the smallest SA. Paired t-test for SA values showed significant difference (p < 0.05) in all wear comparisons between materials and enamel antagonists. The wear of materials were greater than that of their respective enamel antagonists (p < 0.05). One-way ANOVA of the logarithmic means of wear SA revealed significant differences (P<0.05). Post-hoc Tukey test revealed significance for PFM (p < 0.05) with other materials. Wear of all test materials was greater compared to the wear of enamel antagonists. PFM and LD caused the largest and the smallest enamel wear, respectively. CR, LD, and MZr are more resistant than PFM to wear after simulated chewing against enamel.

摘要：本研究旨在分析模拟咀嚼所致人类牙釉质与对颌修复材料间的磨损表面积（surface area, SA），受试修复材料包括复合树脂（composite resin, CR）、金属烤瓷（porcelain fused to metal, PFM）、二硅酸锂（lithium disilicate, LD）及单块氧化锆（monolithic zirconia, MZr）。本研究选取48颗前磨牙作为牙釉质标本，随机分为4组（每组n=12），分别与4种受试材料之一进行250000次加载循环的咀嚼模拟实验，作为咀嚼模拟的对抗侧。对牙釉质标本与修复材料标本进行扫描后，通过数码显微镜开展评估并记录其磨损表面积（单位：mm²）。本研究采用描述性统计、配对t检验、单因素方差分析（one-way ANOVA）及事后Tukey-HSD检验进行统计学分析，检验水准设定为p<0.05。结果显示，牙釉质与LD对颌时磨损表面积最小（0.80 mm²），与PFM对颌时最大（1.74 mm²）；而受试修复材料自身的磨损中，PFM的磨损表面积最大（3.48 mm²），CR最小（2.28 mm²）。针对磨损表面积的配对t检验结果表明，所有受试材料与牙釉质对抗组的磨损对比均存在统计学差异（p<0.05），且各修复材料的磨损程度均显著高于其对应的牙釉质对抗侧（p<0.05）。对磨损表面积的对数均值进行单因素方差分析，结果显示组间差异具有统计学意义（P<0.05）；事后Tukey检验显示，PFM与其余三种受试材料的磨损程度差异均具有统计学意义（p<0.05）。所有受试修复材料的磨损程度均显著高于其对应的牙釉质对抗侧；PFM与LD分别会导致最大和最小的牙釉质磨损。在模拟咀嚼对抗牙釉质的实验中，CR、LD及MZr的抗磨损性能均优于PFM。