Fracture resistance of different esthetic partial coverage restorations | ||||
| Egyptian Dental Journal | ||||
| Article 24, Volume 65, Issue 1 - January (Fixed Prosthodontics, Dental Materials, Conservative Dentistry & Endodontics), January 2019, Page 599-609 PDF (358.54 K) | ||||
| Document Type: Original Article | ||||
| DOI: 10.21608/edj.2019.72817 | ||||
 View on SCiNiTO | ||||
| Authors | ||||
| Shaimaa Ahmed Abo El-Farag1; Mohammed Samir El Nawawy2 | ||||
| 1Lecturer at Department of Fixed Prosthodontics, Faculty of Dentistry, Mansoura University, Egypt | ||||
| 2Lecturer at Department of Operative Dentistry, Faculty of Dentistry, Mansoura University, Egypt | ||||
| Abstract | ||||
| Statement of problem: The main factors for long-term success of indirect esthetic restorations are referred to type of restoration and preparation design. Purpose: The aim of this in vitro study was to evaluate the fracture resistance and modes of failure of composite, ceramic and hybrid partial coverage restorations with different preparation designs. Material and methods: A total of 42 caries-free maxillary human premolars extracted for orthodontic reasons were collected from oral surgery department, Faculty of Dentistry, Mansoura University. Teeth were divided into 3 groups (n=14) according to type of restoration materials. Each group were subdivided into 2 subgroups (n=7) according to preparation design; palatal coverage onlay design in which the palatal cusp was reduced by 2 mm and complete onlay design in which preparation included the reduction of palatal and buccal cusps. Restorations were manufactured from indirectly fabricated composite (SR Nexco), Zirconia-reinforced glass ceramic (VITA SUPRINITY) and Hybrid ceramic (VITA ENAMIC). The finished onlays were luted to prepared teeth using self-adhesive resin cement (Rely X Unicem). Specimens exposed to thermocycling 5000 cycles and then cyclic loading for 500,000 cycles. The fracture resistance of specimens were evaluated in a universal testing machine. The results were analyzed by 2-way ANOVA and Tukey HSD post hoc tests. Results: The results of two way ANOVA test showed that there was statistically significant difference between all groups regardless of the restorative materials and preparation design. Post Hoc test showed a statistically significant difference between three restorative materials in palatal and complete coverage onlay groups (P<0.05). There was no statistically significant difference in the interaction between the types of restoration and preparation deign (P=0.479) (p>0.05). Conclusions: Zirconia-reinforced glass ceramic still the material of choice for palatal and complete onlays because of their strengthening effect on the tooth. Complete onlays showed maximum reinforcement of the tooth structure. | ||||
| Keywords | ||||
| Fracture resistance; laboratory composite; esthetic restorations; partial coverage; onlay design | ||||
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