Original vs. non‐original abutments for screw‐retained single implant crowns: An in vitro evaluation of internal fit, mechanical behaviour and screw loosening

Abstract

Objectives To assess the internal accuracy, mechanical behaviour under static load and screw loosening before and after cyclic loading of implant‐supported crowns restored with original components or with two compatible non‐original brands. Materials and Methods Sixty‐three dental implants were divided into three groups (n = 21 each): Group 1 used original components, and groups 2 and 3 used non‐original components. Internal accuracy was measured throughout a cross section of the sample groups (n = 8) using scanning electron microscopy (SEM) to evaluate the fit for implant–abutments, implant–crowns and crown–abutments. To evaluate load‐bearing capacity, eight samples from each group were loaded until fracture according to ISO Norm 14801. The removal torque value (RTV) was evaluated in the screws connecting the crown with the abutment and the abutment with the implant before and after cyclic loading (2 x 106 cycles) in five samples from each group. The data were analysed using the Kruskal–Wallis test (p < 0.05). Results Statistically significant differences were found among the mean crown–abutment gaps measured in Group 1 (9.3 μm), Group 2 (45.4 μm) and Group 3 (44.9 μm). Higher values for mean load‐bearing capacity were found in Group 1 (1,098 N) than in groups 2 and 3 (1,057 and 973 N, respectively); however, these differences were not statistically significant. Original abutment–implant screws exhibited lower percentages of torque reduction than the non‐originals. Conclusions Enhanced fit is expected when original components are used. The original abutments exhibited lower percentages of torque reduction after cyclic loading than non‐originals.

Original vs Non-Original “Cast-To” Gold Abutment-Implant Connection: Analysis of the Internal Fit and Long-Term Fatigue Performance

“…In the case of nonoriginal abutments the tendency of stress to concentrate at the abutment screw increased the risk for microfracture, and therefore for microgap formation. This was con rmed by the results of a previous investigation [8,34] where original abutments after in vitro fatigue testing showed the best accuracy within their components as well as the lowest values of screw loosening.…”

“…For the internal accuracy test, a sample size of 4 was required for a power of 80% and an alpha value of 0.05 [34]. Statistical analysis was executed using SPSS® software (version 21.0, SPSS Inc., Chicago, IL, USA).…”

Mechanism of and factors associated with the loosening of the implant abutment screw: A review

“…The results showed that the torque loss of the original abutments was significantly lower than that of the copy abutments. In another in vitro study, Alonso‐Pérez et al came to a similar conclusion, verifying that the internal fit of the connection was crucial to the mechanical behavior of the assembly, and so that the original components excelled.…”

Current state‐of‐the‐art and future perspectives of the three main modern implant‐dentistry concerns: Aesthetic requirements, mechanical properties, and peri‐implantitis prevention

“…Although implant‐supported prostheses have demonstrated long‐term success rates, a large number of mechanical complications have been reported . Many studies have shown that the loosening and fatigue fracture of the abutment or prostheses screw are the most common failure modes for screw‐retained prostheses, especially in single implant‐supported restorations in the premolar and molar regions . Moreover, veneer chipping was the main problem observed on all‐ceramic dental crowns and fixed partial dentures .…”

“…[42][43][44][45][46][47][48] Many studies have shown that the loosening and fatigue fracture of the abutment or prostheses screw are the most common failure modes for screw-retained prostheses, especially in single implant-supported restorations in the premolar and molar regions. [49][50][51][52] Moreover, veneer chipping was the main problem observed on all-ceramic dental crowns and fixed partial dentures. 53 These mechanical problems are mostly related to the materials and the design of the prosthetic components.…”