Nigerian Journal of Clinical Practice

ORIGINAL ARTICLE
Year
: 2018  |  Volume : 21  |  Issue : 6  |  Page : 687--691

Effect of cavity design on the fracture resistance of zirconia onlay ceramics


P Oyar1, R Durkan2 
1 Department of Dental Prostheses Technology, Health Services Vocational High School, Hacettepe University, Ankara, Turkey
2 Department of Prosthodontics, Faculty of Dentistry, Afyon Kocatepe University, Afyonkarahisar, Turkey

Correspondence Address:
Prof. P Oyar
Hacettepe Üniversitesi, Saglik Hizmetleri Meslek Yüksekokulu, Dis Protez Teknolojisi Programi, D-Blok, 3 Kat, 06100 Sihhiye, Ankara
Turkey

Objective: The purpose of this study was to evaluate the fracture resistance and failure modes of onlay restorations prepared with different preparation designs. Materials and Methods: A total of 42 extracted, mandibular first molars (36, 46) were used and divided into six groups according to preparation design, as follows 1A: Anatomic preparation of cusps/rounded shoulder margin/occlusal groove; 1B: Flat preparation of cusps/rounded shoulder margin/occlusal groove; 2A: Anatomical preparation of cusps/occlusal groove; 2B: Flat preparation of cusps/occlusal groove; 3A: Complete anatomical reduction of cusps/rounded shoulder margin; 3B: Complete flat reduction of cusps/rounded shoulder margin groups; intact tooth: No preparation. Onlays were constructed with 0.5-mm copings of Zirconia ceramic. The copings were veneered with porcelain (IPS e. max Ceram). All samples were subjected to fracture resistance testing. Data were analyzed with Kruskal–Wallis and Bonferroni-Dunn tests. Results: Fracture resistance varied significantly according to preparation design. Among the anatomic occlusal preparation designs, fracture resistance was significantly lower in Group 3 when compared to Groups 1 and 2 (P < 0.05). Among the flat occlusal preparation designs, fracture resistance was significantly higher in Group 1 when compared to Groups 2 and 3 (P < 0.05). Conclusion: Preparation design affected the fracture resistance of onlay restorations. Cavities with flat occlusal preparation designs, a groove and shoulder margins (1B) resulted in the highest fracture resistance, whereas teeth prepared with a complete reduction of cusps and shoulder margins (3A) had the lowest fracture resistance.


How to cite this article:
Oyar P, Durkan R. Effect of cavity design on the fracture resistance of zirconia onlay ceramics.Niger J Clin Pract 2018;21:687-691


How to cite this URL:
Oyar P, Durkan R. Effect of cavity design on the fracture resistance of zirconia onlay ceramics. Niger J Clin Pract [serial online] 2018 [cited 2020 Aug 11 ];21:687-691
Available from: http://www.njcponline.com/article.asp?issn=1119-3077;year=2018;volume=21;issue=6;spage=687;epage=691;aulast=Oyar;type=0