Clinic of Reconstructive Dentistry, Center of Dental Medicine, Switzerland.
Lithoz GmbH, Vienna, Austria.
Dent Mater. 2020 Apr;36(4):e109-e116. doi: 10.1016/j.dental.2020.01.016. Epub 2020 Jan 25.
The load-bearing capacity of ultra-thin occlusal veneers made of 3D-printed zirconia were compared to the ones obtained by fabricating these reconstructions by CAD/CAM milling zirconia or heat-pressing lithium-disilicate.
On 60 extracted human molars, the occlusal enamel was removed and extended into dentin. Occlusal veneers of 0.5 mm thickness were digitally designed. The specimens were divided into 3 groups (n = 20 each) differing in the restorative material and the fabrication technique of the occlusal veneer. (1) 3DP: 3D-printed zirconia (Lithoz); (2): CAM: milled zirconia (Ceramill Zolid FX); (3) HPR: heat-pressed lithium disilicate (IPS e.max Press). After conditioning procedures, the restorations were adhesively bonded onto the conditioned tooth. Thereafter, all specimens were aged in a chewing simulator by exposure to cyclic fatigue and temperature variations. Subsequently the specimens were statically loaded and the load which was necessary to decrease the maximum load by 20% and initiate a crack (F) and the load which was needed to fracture the specimen (F) were measured. Differences between the groups were compared applying the Kruskal-Wallis (KW) test and the Wilcoxon-Mann-Whitney-Test (WMW: p < 0.05).
The median F values for the groups 3DP, CAM and HPR were 1'650 N, 1'250 N and 500 N. The differences between all three groups were statistically significant (KW: p < 0.0001). The median F values amounted to 2'026 N for the group 3DP, 1'500 N for the group CAM and 1'555 N for the group HPR. Significant differences were found between 3DP and CAM (WMW: p = 0.0238).
Regarding their load-bearing capacity, 3D-printed or milled zirconia as well as heat-pressed lithium disilicate can be recommended as restorative material for ultra-thin occlusal veneers to prosthetically compensate for occlusal tooth wear. Despite statistically significant differences between the restoration materials, all load-bearing capacities exceeded the clinically expected normal bite forces.
比较 3D 打印氧化锆制作的超薄牙合面贴面与 CAD/CAM 铣削氧化锆或热压锂硅瓷制作的超薄牙合面贴面的承载能力。
在 60 颗人离体磨牙上，去除牙合面釉质并扩展至牙本质。数字化设计 0.5mm 厚的牙合面贴面。将标本分为 3 组（每组 20 个），不同之处在于修复材料和牙合面贴面的制作技术。（1）3DP：3D 打印氧化锆（Lithoz）；（2）CAM：铣削氧化锆（Ceramill Zolid FX）；（3）HPR：热压锂硅瓷（IPS e.max Press）。经过预处理程序后，将修复体粘接到预处理过的牙齿上。然后，将所有标本在咀嚼模拟器中进行循环疲劳和温度变化暴露，进行老化处理。随后对标本进行静态加载，并测量使最大载荷降低 20%并开始出现裂纹的载荷（F）和使标本断裂所需的载荷（F）。应用 Kruskal-Wallis（KW）检验和 Wilcoxon-Mann-Whitney-Test（WMW：p<0.05）比较组间差异。
3DP、CAM 和 HPR 组的中位数 F 值分别为 1'650N、1'250N 和 500N。三组间差异均具有统计学意义（KW：p<0.0001）。3DP 组的中位数 F 值为 2'026N，CAM 组为 1'500N，HPR 组为 1'555N。3DP 组与 CAM 组之间存在显著差异（WMW：p=0.0238）。
就其承载能力而言，3D 打印氧化锆、铣削氧化锆和热压锂硅瓷均可作为超薄牙合面贴面的修复材料，用于修复牙合面牙体磨损。尽管修复材料之间存在统计学显著差异，但所有承载能力均超过了临床预期的正常咬合力。
