Impact of different axial wall designs on the fracture strength and stress distribution of ceramic restorations in mandibular first molar

BMC Oral Health

Research

Lidan Zhao¹  Qingsong Jiang²  Xinggang Liu²  Lin He²  Bin Luo²  Xiaolu Sun³ 

[1] Department of Prosthodontics, Affiliated Stomatology Hospital of Guangzhou Medical University, 510013, Guangzhou, China;Department of Prosthodontics, Beijing Stomatological Hospital, School of Stomatology, Capital Medical University, 100050, Beijing, China;Shunyi Hospital, Beijing Traditional Chinese Medicine Hospital, 100010, Beijing, China;

关键词: Ceramic restorations;    Axial wall designs;    Fracture strength;    Stress distribution;    Occlusal distal veneer;   

DOI  :  10.1186/s12903-022-02577-5

 received in 2022-10-11, accepted in 2022-11-08,  发布年份 2022

来源: Springer

【 摘 要 】

BackgroundThe purpose of this study was to investigate the fracture strength and stress distribution of four ceramic restorations.MethodsForty human mandibular first molars were collected and randomized into four groups after establishing the distal defect: full crown group with 4 mm axial wall height (AWH) (FC4); short AWH crown group with 2 mm AWH (SC2); occlusal veneer group with 0 mm AWH (OV0); occlusal distal veneer group with only the distal surface prepared, and 4 mm AWH (OD4). The teeth were prepared according to the groups and the ceramic restorations were completed using celtra duo ceramic blocks. The ceramic thickness of the occlusal surface is about 1.5 mm and the edge is about 1 mm. The failure load values and fracture modes of each group were detected by mechanical test in vitro. According to the groups to establish three-dimensional finite element analysis (FEA) models, a 600 N loading force was applied vertically using a hemispherical indenter with a diameter of 6 mm. and compare the stress distribution under the condition of different restorations.ResultsIn vitro mechanical tests showed that the failure load values were SC2 (3232.80 ± 708.12 N) > OD4 (2886.90 ± 338.72 N) > VO0 (2133.20 ± 376.15 N) > FC4(1635.40 ± 413.05 N). The failure load values of the short AWH crown and occlusal distal veneer were significantly higher than that of occlusal veneer and full crown (P<0.05). The fracture modes of the full crown and occlusal veneer groups were mainly ceramic fractures and some were restorable tooth fractures. The short AWH crown and occlusal distal veneer groups presented with three fracture modes, the proportion of non-restorable tooth fracture was higher. The results of FEA show that under the spherical loading condition, the stress of ceramic was concentrated in the contact area of the loading head, the maximum von Mises stress values were FC4 (356.2 MPa) > VO0 (214.3 MPa) > OD4 (197.9 MPa) > SC2 (163.1 MPa). The stress of enamel was concentrated in the area where the remaining enamel was thinner, the maximum von Mises stress values was OD4 (246.2 MPa) ≈ FC4 (212.4 MPa) > VO0 (61.8 MPa) ≈ SC2 (45.81 MPa). The stress of dentin is concentrated in the root furcation and the upper third region of the root. However, stress concentration was observed at the tooth cervix in the full crown.ConclusionUnder certain conditions, the occlusal distal veneer shows better performance than the full crown.

【 授权许可】

CC BY   
© The Author(s) 2022

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