Heller Hadas, Arieli Adi, Beitlitum Ilan, Pilo Raphael, Levartovsky Shifra
Department of Oral Rehabilitation, the Maurice and Gabriela Goldschleger School of Dental Medicine, Tel Aviv University, Tel Aviv, Israel.
Department of Periodontology and Dental Implantology, Maurice and Gabriela Goldschleger School of Dental Medicine, Tel Aviv University, Tel Aviv, Israel.
Materials (Basel). 2019 Sep 20;12(19):3056. doi: 10.3390/ma12193056.
The static and dynamic load-bearing capacities and failure modes of zirconia crowns screwed to multi-unit abutments (MUAs) with and without a titanium base (T-base) were determined. Thirty-six monolithic zirconia crowns screwed to straight MUAs torqued to laboratory analogs (30 Ncm) were assigned to two groups (n = 18). In group A, the zirconia crowns were screwed directly to the MUAs; in group B, the zirconia crowns were cemented to the T-base and screwed to the MUAs. All specimens were aged in 100% humidity (37 °C) for one month and subjected to thermocycling (20,000 cycles). Afterwards, the specimens underwent static and dynamic loading tests following ISO 14801. The failure modes were evaluated by stereomicroscopy (20×). There was an unequivocally similar trend in the S-N plots of both specimen groups. The load at which the specimens survived 5,000,000 cycles was 250 N for both groups. Group A failed mainly within the metal, and zirconia failure occurred only at a high loading force. Group B exhibited failure within the metal mostly in conjunction with adhesive failure between the zirconia and T-base. Zirconia restoration screwed directly to an MUA is a viable option, but further studies with larger sample sizes are warranted.
测定了带和不带钛基底（T型基底）的、拧在多单位基牙（MUA）上的氧化锆全冠的静态和动态承载能力及失效模式。将36个拧在直形MUA上并扭紧至实验室模拟物（30 Ncm）的整体式氧化锆全冠分为两组（n = 18）。A组中，氧化锆全冠直接拧在MUA上；B组中，氧化锆全冠粘结在T型基底上并拧在MUA上。所有标本在100%湿度（37℃）下老化1个月并进行热循环（20,000次循环）。之后，按照ISO 14801对标本进行静态和动态加载测试。通过体视显微镜（20倍）评估失效模式。两个标本组的S-N曲线存在明显相似的趋势。两组标本在5,000,000次循环时的存活载荷均为250 N。A组主要在金属内部发生失效，氧化锆失效仅在高加载力时出现。B组在金属内部发生失效，大多伴有氧化锆与T型基底之间的粘结失效。直接拧在MUA上的氧化锆修复体是一种可行的选择，但需要进一步进行更大样本量的研究。
