Öztürk Caner, Can Gülşen
Department of Prosthodontics, Faculty of Dentistry, Hatay Mustafa Kemal University, Hatay, Turkey.
Department of Prosthodontics, Faculty of Dentistry, İstanbul Aydın University, Istanbul, Turkey.
J Dent Res Dent Clin Dent Prospects. 2019 Fall;13(4):247-252. doi: 10.15171/joddd.2019.038.
Zirconia restorations with high mechanical properties are the current treatment options for fixed restorations with advantages of high biocompatibility and low pulp irritation. Although the effect of sintering time and temperature on the optical and mechanical properties of zirconia core material were investigated, the effect of these parameters on the translucent monolithic zirconia is still uncertain. This study aimed to evaluate the effect of the changes in sintering temperature and holding time on the mechanical and structural properties of monolithic zirconia. Totally, 340 self-colored (A2) zirconia specimens from two different monolithic zirconia groups (n=170) were prepared, measuring 15.5×12.5×1.2 mm. Then, 17 subgroups (n=10), including the control groups, were sintered according to sintering parameters. XRD analysis was used to determine phase transformations. The surface roughness of the specimens was evaluated using profilometry, and the flexural strength of the specimens was evaluated by the three-point bending test. The data were analyzed using three-way ANOVA and post hoc multiple comparison test with Bonferroni correction (a=0.05) at a significance level of 0.05. Independent-samples t-test was used to compare the subgroups between the control groups (P˂0.05). No tetragonal-to-monoclinic phase transformation was observed in the groups. Changes in the sintering parameters did not significantly affect the surface roughness and flexural strength of monolithic zirconia. Surface roughness values for all the subgroups were above the clinically critical limit. According to the results of this study, changes in the sintering parameters did not affect the surface phase transformation, surface roughness, and flexural strength of monolithic zirconia.
具有高机械性能的氧化锆修复体是目前固定修复的治疗选择，具有生物相容性高和牙髓刺激性低的优点。尽管研究了烧结时间和温度对氧化锆核材料光学和机械性能的影响，但这些参数对半透明整体式氧化锆的影响仍不确定。本研究旨在评估烧结温度和保温时间的变化对整体式氧化锆机械和结构性能的影响。总共制备了来自两个不同整体式氧化锆组（n = 170）的340个自色（A2）氧化锆标本，尺寸为15.5×12.5×1.2 mm。然后，根据烧结参数烧结包括对照组在内的17个亚组（n = 10）。使用XRD分析确定相变。使用轮廓仪评估标本的表面粗糙度，并通过三点弯曲试验评估标本的抗弯强度。在显著性水平0.05下，使用三因素方差分析和带有Bonferroni校正（α = 0.05）的事后多重比较检验对数据进行分析。使用独立样本t检验比较对照组之间的亚组（P˂0.05）。在这些组中未观察到四方相向单斜相的转变。烧结参数的变化对整体式氧化锆的表面粗糙度和抗弯强度没有显著影响。所有亚组的表面粗糙度值均高于临床临界极限。根据本研究结果，烧结参数的变化不影响整体式氧化锆的表面相变、表面粗糙度和抗弯强度。
