Garcia-Hammaker Sabrina, Saglik Berna, Sierraalta Marianella, Razzoog Michael
Biologic and Materials Sciences & Prosthodontics, University of Michigan School of Dentistry, Ann Arbor, MI.
J Prosthodont. 2021 Apr;30(4):329-334. doi: 10.1111/jopr.13275. Epub 2020 Nov 10.
The aim of this study was to investigate the effect of implant screw channel angulation on the fracture resistance of zirconia abutments without artificial aging.
Ten implant replicas were embedded in a jig of autopolymerizing acrylic resin. Using a surveyor and a metallic platform, the implant replicas were mounted centrally and with an angulation of 30°. A maxillary left central incisor crown was fabricated from pattern resin and scanned. The digital design of a monolithic zirconia implant abutment-crown was completed using a 3D imaging software. For all specimens of this group (ASC ), the screw channel was positioned at 25° to the lingual. Following fabrication, the samples were attached onto the embedded implant replicas and manually torqued to 35 Ncm as recommended by the manufacturer. The monolithic zirconia implant abutment-crowns were mounted in a metallic platform, positioned perpendicular to the indenter, and subjected to loading until failure. Crosshead speed was set at 0.5 mm/min for the universal testing machine. Data from a similar in vitro study where straight zirconia custom abutments (ASC ) were subjected to static load until failure was used as a control group. An unpaired Student's t-test was used to determine if fracture resistance based on load at failure and maximum load in each group were significantly different from each other (ASC vs ASC ). Statistical significance level was inferred at p ≤ 0.05 RESULTS: Group ASC fractured at a mean (SD) load of 215.49 (47.10) N and a mean (SD) maximum load of 420.50 (17.18) N. Group ASC fractured at a mean (SD) load of 534.04 (133.77) N and a mean (SD) maximum load of 762.69 (109.59) N. The difference was statistically significant for both mean load and mean maximum load at failure (p ≤ 0.05). The survival rate of 0° zirconia abutments was significantly higher than that of 25° ASC zirconia abutments.
Within the limitations of this in vitro study the mean fracture load was significantly higher in the group with a straight channel angulation.
本研究旨在探讨种植体螺钉通道角度对未经过人工老化的氧化锆基台抗折性的影响。
将十个种植体复制体嵌入自凝丙烯酸树脂夹具中。使用测量仪和金属平台，将种植体复制体居中安装并呈30°角。用模型树脂制作上颌左中切牙冠并进行扫描。使用三维成像软件完成一体式氧化锆种植体基台-牙冠的数字化设计。对于该组（ASC）的所有标本，螺钉通道位于与舌侧呈25°角处。制作完成后，将样本附着在嵌入的种植体复制体上，并按照制造商的建议手动拧紧至35 Ncm。将一体式氧化锆种植体基台-牙冠安装在金属平台上，使其垂直于压头，并进行加载直至破坏。万能试验机的十字头速度设定为0.5 mm/min。来自一项类似体外研究的数据用作对照组，该研究中对直的氧化锆定制基台（ASC）施加静态载荷直至破坏。使用未配对的学生t检验来确定每组基于破坏载荷和最大载荷的抗折性是否存在显著差异（ASC与ASC）。当p≤0.05时推断具有统计学显著性水平。结果：ASC组在平均（标准差）215.49（47.10）N的载荷和平均（标准差）420.50（17.18）N的最大载荷下发生断裂。ASC组在平均（标准差）534.04（133.77）N的载荷和平均（标准差）762.69（109.59）N的最大载荷下发生断裂。破坏时的平均载荷和平均最大载荷的差异均具有统计学显著性（p≤0.05）。0°氧化锆基台的生存率显著高于25° ASC氧化锆基台。
在本体外研究的局限性内，直通道角度组的平均断裂载荷显著更高。
