A study on the fracture strength of collarless metal-ceramic fixed partial dentures

Abstract

PURPOSEThe objective of this study was to evaluate fracture strength of collarless metal-ceramic FPDs according to their metal coping designs.MATERIALS AND METHODSFour different facial margin design groups were investigated. Group A was a coping with a thin facial metal collar, group B was a collarless coping with its facial metal to the shoulder, group C was a collarless coping with its facial metal 1 mm short of the shoulder, and group D was a collarless coping with its facial metal 2 mm short of the shoulder. Fifteen 3-unit collarless metal-ceramic FPDs were fabricated in each group. Finished FPDs were cemented to PBT (Polybutylene terephthalate) dies with resin cement. The fracture strength test was carried out using universal testing machine (Instron 4465, Instron Co., Norwood MA, USA) at a cross head speed of 0.5 mm/min. Aluminum foil folded to about 1 mm of thickness was inserted between the plunger tip and the incisal edge of the pontic. Vertical load was applied until catastrophic porcelain fracture occurred.RESULTSThe greater the bulk of unsupported facial shoulder porcelain was, the lower the fracture strength became. However, there were no significant differences between experimental groups (P > .05).CONCLUSIONAll groups of collarless metal-ceramic FPDs had higher fracture strength than maximum incisive biting force. Modified collarless metal-ceramic FPD can be an alternative to all-ceramic FPDs in clinical situations.

Effect of Incisal Porcelain Veneering Thickness on the Fracture Resistance of CAD/CAM Zirconia All-Ceramic Anterior Crowns

“…Regarding the failure load values in this study, both groups demonstrated failure load values around 1500 N (Table 4) and this finding was in agreement with similar studies conducted by Sundh et al [36], Guazzato et al [37], and Yoon et al [38]. However, it is in contradiction with Kelly [29] who reported failure load values around 600 N, where the load-to-failure test was performed under wet conditions in which a phenomenon termed “chemically assisted crack growth” or “static fatigue” was applied to simulate the active participation of water in intraoral conditions, while in the current study, the load-to-failure test was performed under dry conditions.…”

Marginal fit of anterior 3-unit fixed partial zirconia restorations using different CAD/CAM systems

“…One limitation of this experimental study is that only the marginal fit was evaluated to assess the precision of restorations; the internal fit of the restorations was not considered. Belles et al reported that the internal marginal fits were generally poorer than the external facial marginal fit,25 and several authors have studied the internal fit of restorations 26-28. Further investigations are needed to measure both the marginal and internal fits.…”

Fracture Resistance of Aged Full-Coverage All-Ceramic Zirconia and Metal-Ceramic Restorations of Implant-Supported Fixed Partial Dentures

“…They found that collarless metal-ceramics FPD groups had lower fracture strength than the metal collared control group (p<0.05), and however, the tested groups were not significantly different in terms of fracture resistance, the fracture resistance was generally higher than maximum incisive biting force in the study groups. Thus, it might be stated that by changing the type of coping in the process of fabrication of metalceramics FPDs, high-strength restorations can be fabricated [29].…”