Department of Prosthodontics, Guanghua School of Stomatology, Guangdong Provincial Key Laboratory of Stomatology, Sun Yat-sen University, No. 56 Lingyuan West Road, Guangzhou, 510055, China.
Department of Stomatology, The First Affiliated Hospital of Guangzhou University of Chinese Medicine, Guangzhou, China.
Clin Oral Investig. 2020 Sep;24(9):3157-3167. doi: 10.1007/s00784-019-03190-7. Epub 2020 Feb 7.
To compare stress distribution and failure probability in maxillary premolars restored by simple occlusal veneer (SOV) and buccal-occlusal veneer (BOV) with 3 different CAD/CAM materials.
A maxillary premolar was digitized by a micro-CT scanner. Three-dimensional dynamic scan data were transformed, and finite element models of 2 different models (SOV and BOV restored teeth) were designed. Three different CAD/CAM materials, including lithium disilicate glass ceramic (LD) IPS e.max CAD, polymer-infiltrated ceramic-network (PICN) Vita Enamic, and resin nano-ceramic (RNC) Lava Ultimate, were designated to both veneers. Maximum principle stresses were determined by applying a 300-N axial load to the occlusal surface. Weibull analyses were performed to calculate the failure probability of the models.
LD-restored teeth showed the highest stress in the veneer, lowest stress in substrate teeth, and lowest failure probability for the overall system; RNC-restored teeth showed the lowest stress in the veneer, highest stress in substrate teeth, and highest failure probability. No significant differences were found in the cement layer among the different models. No significant differences of stress and failure probability existed between SOV and BOV preparations.
CAD/CAM composite resin occlusal veneers bear lower maximum stress than ceramic veneers. Teeth restored by composite veneers are more prone to failure than those restored by ceramic veneers. Additional reduction of the buccal surface did not increase the stress on the occlusal veneer under axial load.
Both occlusal veneers could be used under physiological masticatory force. CAD/CAM glass ceramic was safer than composite resins.
比较三种不同 CAD/CAM 材料制作的简单（SOV）和颊面（BOV）牙合面贴面修复上颌前磨牙的应力分布和失败概率。
通过微 CT 扫描仪对上颌前磨牙进行数字化。对三维动态扫描数据进行转换，设计两种不同模型（SOV 和 BOV 修复牙）的有限元模型。将三种不同的 CAD/CAM 材料，包括锂硅玻璃陶瓷（LD）IPS e.max CAD、聚合物渗透陶瓷网络（PICN） Vita Enamic 和树脂纳米陶瓷（RNC）Lava Ultimate，分别应用于两种贴面。通过在牙合面施加 300-N 的轴向载荷来确定最大主应力。进行威布尔分析以计算模型的失效概率。
LD 修复牙的贴面中应力最高，基牙中应力最低，整体系统的失效概率最低；RNC 修复牙的贴面中应力最低，基牙中应力最高，失效概率最高。不同模型的粘结层之间没有明显差异。SOV 和 BOV 预备体之间的应力和失效概率没有显著差异。
CAD/CAM 复合树脂牙合面贴面比陶瓷贴面承受的最大应力更低。复合树脂修复的牙齿比陶瓷贴面修复的牙齿更容易失效。颊面的进一步减少在轴向载荷下不会增加牙合面贴面的应力。
两种牙合面贴面都可以在生理咀嚼力下使用。CAD/CAM 玻璃陶瓷比复合树脂更安全。
