Department of Operative Dentistry and Dental Materials, Dental School, Federal University of Uberlândia, Uberlândia, Brazil.
Department of Periodontology and implantology, Dental School, Federal University of Uberlândia, Uberlândia, Brazil.
Dent Traumatol. 2021 Apr;37(2):215-222. doi: 10.1111/edt.12631. Epub 2020 Dec 4.
BACKGROUND/AIM: Little is known about the effect of dental trauma and mouthguards (MG) on teeth with ceramic laminate veneers (CLV). The aim was to evaluate the influence of CLV thickness and the presence of a MG with and without antagonist tooth contact on impact stresses during dental trauma.
Twelve 2D-finite element models of a head with maxillary structures and upper incisors, six with and six without antagonist tooth, were created in three CLV conditions: sound incisor (no CLV), 0.3 mm CLV, and 1.0 mm CLV. These were evaluated with and without a 4.0-mm ethylene-vinyl acetate MG, with and without an antagonist tooth. An impact analysis was performed in which the head frontally hits a rigid surface at a speed of 1 m/s (3.6 km/h). The results were analyzed using Critical modified von Mises (MPa). The mean of the 10% highest modified von Mises stresses in each structure was collected.
MG presence substantially reduced impact stresses in the CLV and tooth structures. The contact of the antagonist tooth promoted better stress distribution and reduced the stress levels in the traumatized tooth. Critical stress areas were found in the palatal enamel, incisal enamel, labial cervical area, and enamel under the CLV for all models without MG. In the models with MG, the stresses reduced significantly. Critical modified von Mises stress showed that sound or prepared enamel experienced more critical impact stresses than 0.3 or 1.0-mm thick CLV.
The use of 4.0 mm EVA mouthguard reduced the impact stress levels in models with 0.3-mm CLV and 1.0-mm CLV, similar to a sound tooth. The contact of an antagonist tooth and the MG better distributed the stresses and reduced the impact stress in the traumatized tooth.
背景/目的：对于带陶瓷层压贴面（CLV）的牙齿，牙科外伤和防护牙套（MG）的影响知之甚少。本研究旨在评估 CLV 厚度以及带或不带对抗牙接触的 MG 的存在对牙科外伤时冲击应力的影响。
创建了带有上颌结构和上颌切牙的 12 个二维有限元头部模型，其中 6 个有对抗牙，6 个没有对抗牙。在三种 CLV 条件下（无 CLV 的健康切牙、0.3mm CLV 和 1.0mm CLV）对这些模型进行了评估：有或没有 4.0mm 乙烯-醋酸乙烯共聚物 MG，有或没有对抗牙。以 1m/s（3.6km/h）的速度从前部撞击刚性表面，对头进行冲击分析。使用临界修正 von Mises（MPa）分析结果。收集每个结构中 10%最高修正 von Mises 应力的平均值。
MG 的存在大大降低了 CLV 和牙齿结构的冲击应力。对抗牙的接触促进了更好的应力分布，降低了受伤牙齿的应力水平。在所有没有 MG 的模型中，都在腭侧釉质、切缘釉质、唇侧颈区和 CLV 下的釉质中发现了临界应力区。在有 MG 的模型中，应力显著降低。临界修正 von Mises 应力表明，健康或预备釉质比 0.3mm 或 1.0mm 厚的 CLV 经历更临界的冲击应力。
使用 4.0mm EVA 防护牙套可降低 0.3mm CLV 和 1.0mm CLV 模型中的冲击应力水平，与健康牙齿相似。对抗牙和 MG 的接触更好地分布了应力，并降低了受伤牙齿的冲击应力。
