Statement of problem

Clinical studies on the wear properties of different zirconia surfaces are lacking. Selecting a surface that causes and undergoes minimal wear will help improve clinical outcomes.

Purpose

The purpose of this clinical study was to evaluate and compare the wear over 1 year use of glazed zirconia (GZ) and polished zirconia (PZ) crowns opposing natural enamel and the wear of natural enamel opposing PZ and GZ crowns.

Material and methods

This prospective, split mouth, randomized clinical trial included 14 participants requiring complete coverage crowns on first molars, bilaterally, in a completely dentate mandibular arch. GZ and PZ crowns were cemented according to a randomization chart. Polyvinyl siloxane impressions were made immediately and 1 year after the cementation of the crowns. The respective casts were scanned by using a 3D scanner and a software program to measure the amount of linear wear of zirconia crowns and opposing natural teeth. Wear was observed in 8 groups: PZ crowns, GZ crowns, natural enamel opposing natural enamel in the molar and premolar regions (NE-M and NE-PM), natural enamel opposing PZ crowns in the molar region (NE-PZ-M), natural enamel opposing GZ crowns in the molar region (NE-GZ-M), natural enamel opposing PZ crowns in the premolar region (NE-PZ-PM), and natural enamel opposing GZ crowns in the premolar region (NE-GZ-PM). A descriptive analysis was followed by comparison between groups by using a repeated-measure ANOVA with post hoc adjustments (α=.05).

Results

The mean wear (μm) observed was as follows (in ascending order): PZ crowns (13 ±3), NE-PM (13 ±1), GZ crowns (27 ±9), NE-M (34 ±3), NE-PZ-PM (44 ±18), NE-PZ-M (63 ±22), NE-GZ-PM (69 ±21), NE-GZ-M (113 ±33). Wear of GZ and PZ crowns was less than wear of NE-M. The difference was statistically significant when comparing PZ with NE-M (P<.001, CI=-17 to -24). Wear of NE-GZ-M and NE-PZ-M was higher than wear of NE-M, with a statistically significant difference (P<.001, CI=-49 to -107 and P =.004, CI=-8 to -49, respectively). Wear of NE-GZ-M was more than that of NE-PZ-M, and the difference was statistically significant (P<.001, CI=-68 to -32). Wear of NE-PZ-PM and NE-GZ-PM was also more than the wear of NE-PM, and the difference was statistically significant (P<.001, CI=-17 to -43 and P<.001, CI=-39 to -70).

Conclusions

PZ and GZ crowns wear substantially with time, with lesser wear observed in PZ crowns. PZ and GZ crowns also cause more wear in opposing natural enamel than natural enamel antagonists, with the highest wear caused by GZ crowns.

中文翻译：

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评估釉面和抛光氧化锆牙冠和对侧天然牙的磨损：一项临床试验研究

问题陈述

缺乏对不同氧化锆表面磨损性能的临床研究。选择导致磨损和磨损最小的表面将有助于改善临床结果。

目的

本临床研究的目的是评估和比较使用釉面氧化锆 (GZ) 和抛光氧化锆 (PZ) 牙冠对抗天然牙釉质和天然牙釉质与 PZ 和 GZ 牙冠的磨损超过 1 年的磨损情况。

材料与方法

这项前瞻性、分口、随机临床试验包括 14 名参与者，他们需要在双侧完全齿状下颌弓的第一磨牙上完全覆盖牙冠。GZ 和 PZ 牙冠根据随机化图表进行粘接。在牙冠粘接后立即和 1 年后制作聚乙烯硅氧烷印模。通过使用 3D 扫描仪和软件程序对各个铸件进行扫描，以测量氧化锆牙冠和对侧天然牙的线性磨损量。在 8 组中观察到磨损：PZ 牙冠、GZ 牙冠、天然牙釉质与磨牙和前磨牙区域的天然牙釉质（NE-M 和 NE-PM）、天然牙釉质与磨牙区域的 PZ 牙冠相对（NE-PZ-M） , 天然牙釉质在磨牙区 (NE-GZ-M) 与 GZ 牙冠相对，天然牙釉质在前磨牙区 (NE-PZ-PM) 对着 PZ 牙冠，天然牙釉质在前磨牙区 (NE-GZ-PM) 对着 GZ 牙冠。描述性分析之后，通过使用重复测量方差分析和事后调整 (α=.05) 进行组间比较。

结果

观察到的平均磨损 (μm) 如下（按升序排列）：PZ 牙冠 (13±3)、NE-PM (13±1)、GZ 牙冠 (27±9)、NE-M (34±3)、 NE-PZ-PM (44 ±18)、NE-PZ-M (63 ±22)、NE-GZ-PM (69 ±21)、NE-GZ-M (113 ±33)。GZ 和 PZ 牙冠的磨损小于 NE-M 牙冠的磨损。将 PZ 与 NE-M 进行比较时，差异具有统计学意义（P <.001，CI = -17 至 -24）。NE-GZ-M 和 NE-PZ-M 的磨损高于 NE-M 的磨损，差异有统计学意义（P <.001, CI=-49 to -107 and P  =.004, CI=-8到 -49，分别）。NE-GZ-M的磨损大于NE-PZ-M，差异有统计学意义（P<.001，CI=-68 到 -32）。NE-PZ-PM和NE-GZ-PM的磨损也大于NE-PM的磨损，差异有统计学意义（P <.001，CI=-17～-43，P <.001，CI =-39 到 -70）。

结论

PZ 和 GZ 牙冠随着时间的推移磨损显着，在 PZ 牙冠中观察到的磨损较小。与天然牙釉质拮抗剂相比，PZ 和 GZ 牙冠也会导致对侧天然牙釉质的磨损更多，其中 GZ 牙冠造成的磨损最大。