Clinical Assistant Professor, Department of Conservative Dentistry, Kyung Hee University Dental Hospital, Seoul, Republic of Korea.
Professor, Department of Restorative Dentistry, Oregon Health & Science University, Portland, Oregon.
J Prosthet Dent. 2022 May;127(5):766.e1-766.e9. doi: 10.1016/j.prosdent.2022.01.034. Epub 2022 Mar 8.
During the trial placement of zirconia restorations, contamination of the bonding surface is inevitable. Although cleaning methods for contaminated surfaces have been described, a method of preventing saliva contamination of the bonding surface of zirconia restorations is lacking.
The purpose of this in vitro study was to investigate an ethyl cellulose coating as an evaluation agent to mitigate the effects of saliva contamination on the bond strength of zirconia restorations.
Experimental groups representing different cleaning methods of tetragonal yttria-stabilized tetragonal zirconia polycrystal (4Y-TZP) surfaces were investigated for shear bond strength with a resin luting agent, and the failure mode was analyzed. The 9.0×7.0×5.0-mm zirconia blocks (n=72) were assigned as follows: Group N: uncontaminated control; Group CU: contaminated with saliva, followed by ultrasonic cleaning with ethanol; Group CI: contaminated with saliva, followed by application of a zirconia cleaner; Group PCW: preapplication of a zirconia primer, contaminated with saliva, followed by cleaning with water spray; Group ECU: precoating with the ethyl cellulose agent, contaminated with saliva, followed by removal of the agent in an ultrasonic bath with ethanol. Each group was divided into 3 subgroups (immediate, short-term aging, and long-term aging), and the shear bond strength was measured (n=24). To analyze the bonding surface characteristics, the contact angle was measured (n=5). The surfaces of the zirconia specimens in each experimental group were evaluated by using a field emission scanning electron microscope (n=5). Time-of-flight secondary ion mass spectroscopy was used for the chemical analysis of the conditioned surfaces (n=3). A 2-way analysis of variance (ANOVA) with main effect model for shear bond strength results and a 1-way ANOVA for contact angle data were performed as statistical analysis, followed by the Bonferroni post hoc test (α=.05).
The shear bond strength was significantly higher in the ECU group than in the groups with the other cleaning methods (P<.05). After the removal of ethyl cellulose with ethanol, the contact angle and surface topography were found to be similar to those of the control group, and no saliva contaminants were identified in the spectroscopy analysis.
Coating with ethyl cellulose may protect the bonding surface of zirconia restorations from salivary contamination better than cleaning a contaminated surface.
在氧化锆修复体的试戴过程中，不可避免地会污染粘结面。虽然已经描述了污染表面的清洁方法，但缺乏防止唾液污染氧化锆修复体粘结面的方法。
本体外研究的目的是评估乙基纤维素涂层作为一种评价剂，以减轻唾液污染对氧化锆修复体粘结强度的影响。
研究了不同的四方氧化钇稳定四方氧化锆多晶（4Y-TZP）表面清洁方法的实验组，以树脂水门汀的剪切粘结强度为指标，并对其破坏模式进行了分析。将 9.0×7.0×5.0mm 的氧化锆块（n=72）分为以下几组：N 组：未污染的对照组；CU 组：污染后用乙醇进行超声清洗；CI 组：污染后用氧化锆清洁剂处理；PCW 组：应用氧化锆底涂剂，污染后用喷雾水清洗；ECU 组：用乙基纤维素剂预涂，污染后用乙醇超声浴去除。每组又分为 3 个亚组（即时、短期老化和长期老化），测量剪切粘结强度（n=24）。为分析粘结面特性，测量接触角（n=5）。使用场发射扫描电子显微镜（n=5）对每组氧化锆试件的表面进行评估。用场发射扫描电子显微镜对条件表面进行化学分析（n=3）。对剪切粘结强度结果进行双因素方差分析（ANOVA），对接触角数据进行单因素方差分析，然后进行 Bonferroni 事后检验（α=.05）。
与其他清洁方法相比，ECU 组的剪切粘结强度明显更高（P<.05）。用乙醇去除乙基纤维素后，接触角和表面形貌与对照组相似，光谱分析未发现唾液污染物。
与清洁污染表面相比，乙基纤维素涂层可更好地保护氧化锆修复体的粘结面免受唾液污染。
