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Journal of Oral Science & Rehabilitation 32 Volume 2 | Issue 3/2016 F r a c t u r e r e s i s t a n c e o f p r o v i s i o n a l i m p l a n t - p r o s t h e t i c a b u t m e n t s alabutmentssubjectedtostaticloading.5 Various authors have proposed similar variables to the present test design in terms of specimen design and distribution, as well as crosshead speed and movement.30–35 Thecrossheadspeedincompres- sion testing in this study was 0.5 mm/min, a speedestablishedfromtheliteraturereviewcon- ducted in preparationforthe studyto ensure use of the same speed used in the majority of other similar studies (standardization being important when it comes to comparison of studies).30–36 However, pure compression studies do appearto be adequate for researching the fracture resis- tance of implant-prosthetic structures. The idealprocedureinastudyofthesecharacteristics is to subject specimens to dynamic loading– artificialagingofthespecimens–beforeperform- ing the static load testing. For this reason, the presentstudydividedthespecimens(n=40)into two subgroups and subjected half to a prior fa- tiguing process to simulate the aging of the abutments. Like compression testing, the fa- tiguing process must meet criteria established in ISO 14801:2007.39 The literature contains several studies that have subjected specimensto aging priortotest- ing.27, 28, 30, 34–39 Stimmelmayr et al. used the same test machine (Mechatronic), the same specimen distribution and frequency param- eters (1.2 Hz), as well as impact speed (10 mm/s), as the present work36 to determine the fracture resistance of fatigued zirconia abut- ments. Artificial aging or dynamic loading re- produces conditions in the mouth to which the implant-prosthetic abutments are exposed, reducing their fracture resistance evaluated by static load compression testing.27, 28, 30, 34–39 Several studies have observed that the use of substances that simulate saliva, creating a moist environment, generates environmental conditions that negatively affect the fatigued implant abutment.27, 28 Steinebrunner et al. carried outfatiguetesting ofimplant-prosthetic abutments submerged in artificial saliva, imi- tating intra-oral conditions in order to evaluate the influence of the fluid medium.28 A control group was made up of specimens subjected to fatiguing in ambient air. The results showed that the artificial saliva acted as an aggressive environment, affecting the implants’ fracture resistance.28 The oral environment is clearly an important factor to consider when evaluating dental implants’ mechanical properties and that the present study did not simulate oral condi- tions by exposing specimens to artificial saliva can be considered a significant limitation. To date, few studies have provided scienti- fic evidence in relation to provisional abut- ments, while definitive abutments have been extensively studied. The range of fracture re- sistance values obtained in similar studies is 714–906 N.28, 34, 35 The data obtained in the present studyforthe definitive abutments (TD), whether subjected to fatiguing or not, and the TP abutments not subjected to fatiguing fall within this range and even exceed them. San- nino and Barlattani obtained values of 906 N in static load testing of definitive titanium abut- ments.34 Truninger et al. evaluated the fracture resistance of zirconia abutments, using titani- um abutments as a control group, and obtained a mean value of 714 N.35 It is important to con- sider the fracture resistance levels cited in the literature that implant-prosthetic abutments must support in the oral environment under normal conditions. Ferrario et al. affirmed that the occlusal load that a single tooth must sup- port in the anterior region is 150 N; this study included 52 patients who used a bite force transducer to register occlusal force.38 In this scenario, the present results confirm that all of the abutments analyzed, whether subjected to fatiguing or not, fulfilled the requirements for survival in the anterior region. Conclusion The Grade IV titanium definitive abutments obtained the highest fracture resistance and deformation values. The nonfatigued PEEK resin provisional abutments and fatigued castable methacrylate provisional abutments obtained the lowest fracture resistance values. The Grade III titanium provisional abutments showed the highest deformation values. Fa- tiguing did not influence fracture resistance significantly or the abutments’ elastic perfor- mance. All of the abutments tested fulfilled the mechanical requirements for survival in the oral environment. Competing interests The authors declare that they have no compet- ing interests related to this study. No financial support was received for this study.