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Journal of Oral Science & Rehabilitation Volume 2 | Issue 3/2016 31 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 stable performance despite cyclic loading, such that its performance was not affected by fa- tiguing. The Mann–Whitney test was applied to evaluate differences between fatigued and non- fatigued specimens and a p-value of 0.401 was obtained, indicating that resistance to fracture was similar between the two groups (fatigued/ nonfatigued). Likewise, within the individual groups, no significant differences were found between fatigued or nonfatigued subgroups (CMP: p = 0.143; PP: p 1.000; TP: p = 0.190; TD:p 0.286), although the CMP and TP groups did show a certain tendency toward difference, but this did not reach statistical significance. In data analysis of the deformation that the restorations suffered up to the point of fracture or mechanical failure (in mm; Tables 6 & 7), de- formation values for specimen 2 in the TD group and specimen 5 in the TP group (not fatigued) were discarded from analysis owing to various technical failures in the study procedure. The same occurred with two specimens (1 and 4) in the CMP group (subjected to fatiguing). In deformation data analysis of groups not sub- jectedtofatiguing(Table8), itwasfoundthatthe group that presented the highest deformation valueswastheTPgroup.Thegroupwiththeleast deformationwastheTD group.The PPand CMP groups showed similar median values, but a dis- persed range of values. The Kruskal–Wallis test showed that there were no overall significant differences (p = 0.187). The Mann–Whitney test found that the only significant difference occurred between the CMP and TD groups, the TDgroupshowingthelowestdeformationvalues (CMP–PP:p=0.421;CMP–TP:p=1.000;PP–TP: p=0.556;CMP–TD:p=0.032;PP–TD:p=0.190; TP–TD: p = 0.114). Asfordeformationdataanalysisofspecimens subjected to fatiguing (Table 9), the TD and CMP groups underwent the least deformation. The PP andTPgroupsshowedsimilarmedianvalues,but the range ofvalueswas morewidelydispersed in the TP group. The group that underwent the greatest deformation was the TP group. When homogeneity was analyzed between groups, the Kruskal–Wallis test found a p-value of 0.022, indicatinghomogeneitybetweenthegroups.The Mann–Whitney test for paired groups only iden- tifiedstatisticallysignificantdifferencesbetween theTDandPPgroups,withtheTDgroupobtaining lower deformation values (CMP–PP: p = 0.071; CMP–TP: p = 0.143; PP–TP: p = 0.841; CMP–TD: p = 0.571; PP–TD: p = 0.008; TP–TD: p = 0.056). In orderto determinewhetherfatigue influenced deformation, specimens subjected to fatiguing were compared with those not subjected to fa- tiguing,butnosignificantdifferenceswerefound (CMP: p = 0.143; PP: p = 1.000; TP: p = 0.905; TD: p = 0.286). Discussion Nowadays, many patients regard dental esthet- ics as one ofthe principal requirements ofdental treatment. In the case of implant dentistry, a range of factors influence esthetic outcomes, including color, contour, the natural appearance ofthe definitive prosthesis, and most important- ly, the topography and appearance of the peri- implant soft tissue.2 Soft-tissue management is not straightforward, as multiple factors affect the final outcome, in which the provisional pros- thesis plays a key role.2, 4 Given the importance of provisionalization as a part of dental implant treatment, the present study set out to evaluate the resistance to fracture of implant-supported provisional prostheses of different materials (ti- tanium, PEEKresin and methacrylate) subjected to fatiguing. While definitive prostheses have been extensively studied, little research has in- vestigated fracture resistance and the influence of fatigue on provisional abutments in vitro. The present study protocol was designed to fulfill the test geometry specified in ISO 14801:2007 for testing single-post endos- seous dental implants, in that the implant made a 30° anglewiththetest machine’s load cell.30–39 This geometry has been used in most other studies of similar characteristics to the present one.34–37 The material used to set the implant in the cylinder—epoxy resin—was chosen for its elastic modulus > 3 GPa, also required by ISO 14801:2007, and because this material has been used in similar studies too.30–37 All of the abutments were tested without placing restor- ations on them, as was the case in Truninger et al., in which the abutments were subjected to loadtestingwithout bearing restorations.35 Like- wise, Rack et al. tested abutments without pla- cing restorations on them, but soldered a steel sphere of 10 mm in diameter to the coronal part of the abutment so that the force applied would be evenly distributed throughout the abutment structure.33 The choice of test design was based on Agustín-Panadero et al., who studied provision- Volume 2 | Issue 3/201631