Statement of problem

The debonding of zirconia cantilevered resin-bonded fixed dental prostheses remains a technical complication because zirconia’s chemical inertness impedes adequate surface preparation for bonding. Limited clinical evidence on the performance of various pretreatment methods for the bonding surface of zirconia resin-bonded fixed dental prostheses is available.

Purpose

The present prospective, randomized, controlled clinical trial aimed at evaluating the performance of zirconia resin-bonded fixed dental prostheses prepared with nanostructured alumina coating.

Material and methods

The study adopted a prospective, randomized, controlled, double-blind (patients, operator) design to compare the performance of nanostructured alumina coating with that of conventional airborne-particle abrasion. Twenty-seven healthy patients needing a replacement of a missing maxillary or mandibular central or lateral incisor were screened and rated to be eligible, and 31 zirconia cantilevered resin-bonded fixed dental prostheses were randomly allocated into 1 of 2 groups. The first group (n=15), where the restoration bonding surface was airborne-particle abraded with 50-μm alumina, served as a control group. In the second group (n=16), the restorations were pretreated with nanostructured alumina coating. Treatment and data collection were standardized. The primary outcome evaluated was the survival of the RBFDPs as defined by the restoration not debonding. The Kaplan-Meier analysis of cumulative survival was performed, and nonparametric tests were used to determine patient-specific differences between both study groups (age, sex, restored arch, tooth replaced, bonding surface area) (α=.05). Retainer wing surfaces of debonded resin-bonded fixed dental prostheses were inspected under a scanning electron microscope.

Results

Within a mean ±standard deviation observation period of 22.4 ±7.7 months (minimum, 8.3; maximum, 37.9 months), 3 debondings occurred, and the survival rate was 90.3%. The survival rate was 93.8% for the nanostructured alumina coating and 86.7% for the control group, with no statistically significant differences (log-rank, P=.54). No patient-specific differences were found between study groups (P>.05). As per the scanning electron micrographs, the majority of the nanostructured alumina-coated surfaces had large areas of nanostructured alumina residue, whereas the airborne-particle abraded surfaces exhibited predominantly adhesive failure with less cement residue.

Conclusions

Over a mean observation period of 2 years, both zirconia pretreatments showed promising and comparable clinical results; therefore, nanostructured alumina coating could be regarded as a viable alternative pretreatment method to airborne-particle abrasion.

中文翻译：

---

纳米结构氧化铝涂层对氧化锆悬臂树脂粘结固定义齿临床性能的影响：前瞻性、随机、对照临床试验长达 3 年的结果

问题陈述

氧化锆悬臂式树脂粘合固定牙科修复体的剥离仍然是一个技术难题，因为氧化锆的化学惰性阻碍了为粘合进行充分的表面准备。关于氧化锆树脂粘结固定义齿的粘结表面的各种预处理方法的性能的临床证据有限。

目的

本前瞻性、随机、对照临床试验旨在评估用纳米结构氧化铝涂层制备的氧化锆树脂粘合固定牙科修复体的性能。

材料与方法

该研究采用前瞻性、随机、受控、双盲（患者、操作员）设计来比较纳米结构氧化铝涂层与传统空气颗粒磨损的性能。需要更换缺失的上颌或下颌中切牙或侧切牙的 27 名健康患者经过筛选并被评为合格，31 名氧化锆悬臂式树脂粘合固定义齿被随机分配到 2 组中的 1 组。第一组 (n=15) 作为对照组，其中修复体结合表面是用 50 μm 氧化铝进行的空气悬浮颗粒磨损。在第二组 (n=16) 中，修复体使用纳米结构氧化铝涂层进行预处理。治疗和数据收集是标准化的。评估的主要结果是 RBFDP 的存活率，定义为修复体未脱粘。对累积生存率进行了 Kaplan-Meier 分析，并使用非参数检验来确定两个研究组之间的患者特异性差异（年龄、性别、修复后的牙弓、更换的牙齿、粘接表面积）(α=.05)。在扫描电子显微镜下检查脱粘树脂粘合固定义齿的固定翼表面。

结果

在平均±标准差22.4±7.7个月（最小8.3个月；最大37.9个月）的观察期内，发生3次脱粘，存活率为90.3%。纳米结构氧化铝涂层的存活率为 93.8%，对照组为 86.7%，无统计学差异（log-rank，P =.54）。研究组之间未发现患者特异性差异 ( P >.05)。根据扫描电子显微照片，大多数纳米结构氧化铝涂层表面都有大面积的纳米结构氧化铝残留物，而空气颗粒磨损表面主要表现为粘附失效，水泥残留物较少。

结论

在平均 2 年的观察期内，两种氧化锆预处理均显示出有前途且具有可比性的临床结果；因此，纳米结构氧化铝涂层可被视为空气颗粒磨损的一种可行的替代预处理方法。