树脂基覆膜材料对牙根面保护作用的耐久性

Durability of protective effect of resin-based coating material on root surface

目的:比较树脂基覆膜材料和一步法自酸蚀粘接剂对牙根面保护作用的耐久性。方法:制备人离体后牙牙根试样和牙本质盘试样,表面分别使用PRG Barrier Coat(PRG)和一步法自酸蚀粘接剂Clearfil S3Bond(CS3)处理,去离子水中静置24 h备用。对牙根和牙本质盘试样分别进行:(1)水老化及抗酸脱矿实验:人离体牙牙根试样水老化处理14 d后,在脱矿缓冲液(p H 4.5)中脱矿4 d,扫描电子显微镜观察横断面;(2)牙刷磨损实验:对已覆盖PRG和CS3后的人离体后牙牙本质盘表面进行牙刷磨损,表面粗糙度仪测量磨损深度(Ry,μm),One-Way ANVOA法进行统计分析。结果:PRG和CS3覆膜厚度分别为(47.1±27.3)μm和(5.7±2.1)μm,水老化实验后二者覆膜形态无明显改变,下方牙本质无脱矿。PRG和CS3的磨损深度随牙刷磨损次数增加而加深,PRG组磨损深度小于CS3组(P<0.05)。结论:PRG水老化实验后抗酸蚀脱矿作用和CS3相似,耐牙刷磨损性能优于CS3。

Objective： To compare the durability of resin-based root-surface coating material and all-inone self-etching adhesive on root surface in vitro. Methods： Human extracted premolars or molars with intact roots were selected. The cementum was removed using a periodontal scaler to expose root dentin.The root surface was coated with an acid-resistant nail varnish,leaving a window of 3 mm × 3 mm on the exposed dentin. The window was covered with either PRG Barrier Coat（ PRG） or Clearfil S3Bond（ CS3）. After water aging for 14 d,specimens were immersed in acid buffer at p H 4. 5 for 4 d and the demineralization buffer was changed every 24 h. Then the specimen was split longitudinally through the center of the ‘window＇and the cross-sectional surface was observed with scanning electron microscope（ SEM）. After fixed and dehydrated,the prepared samples were coated with platinum. The coating material,root dentin and the interface was observed by scanning electron microscope（ SEM）. The thickness of the coating material was measured on the SEM images. Regarding toothbrush wear test,coronal dentindisks were prepared and covered with PRG and CS3,respectively. After storage in water for 24 h,the specimen was subjected to the toothbrush wear tester for 100,200,300,500,700,1 500 brushing cycles. A slurry of fluoride toothpaste（ 1 ∶ 2 ratio of toothpaste and deionized water by weight） was used and the brushing load was 300 N. The surface microstructure of remaining coating material was analyzed using SEM. The wear depths were determined by a profilometer. Statistical analysis was performed with SPSS 20. 0 by one-way ANOVA. The level of significance was at 0. 05. Results： Application of PRG Barrier Coat produced a coating layer of（ 47. 1 ± 27. 3） μm,while CS3 presented a thin film of（ 5. 7 ±2. 1） μm in thickness. The exposed dentin was hermetically sealed and no obvious gap was observed at the interface in both PRG and CS3 groups. There was no dentin demineralization observed in both groups after water aging. The wear depths of PRG and CS3 increased along with the numbers of brushing cycles.PRG wore at a significant lower pace than CS3 did（ P〈0. 05）. Conclusion： PRG coating resin had similar performances as CS3 on protecting root dentin from demineralization after water aging. What ＇s more,PRG demonstrated a higher toothbrush wear resistance than CS3. We concluded that PRG Barrier Coat contained S-PRG filler may be an effective coating material for protecting exposed root from both chemical and mechanical challenges. Further studies should be carried out to evaluate the long-term reliability of the rootsurface coating materials under the clinical setting.