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Si us plau utilitzeu sempre aquest identificador per citar o enllaçar aquest document: https://hdl.handle.net/2445/207473
Mechanical resistance to fracture of narrow platform dental implants with hexagonal external connection submitted to implantoplasty with different bone levels and crown/implant ratios. An in vitro study.
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[eng] INTRODUCTION: Peri-implantitis is an inflammatory condition that affects soft and hard tissues around dental implants and that can lead to implant failure. Implantoplasty is a procedure that allows implant surface decontamination by removing the implant threads and smoothening its surface, thus limiting disease progression. Bone loss associated with peri-implantitis will increase the clinical crown-to-implant ratio which, in turn, has been reported to decrease implant resistance. HYPOTHESIS: Implantoplasty significantly reduces implant width and therefore decreases its resistance to fracture, especially in the implant platform area. Moreover, lower bone levels and higher crown-to-implant ratios negatively affect the resistance to fracture of external connection 3.5-millimeter-wide platform implants with and without implantoplasty. OBJECTIVES: To determine the effect of implantoplasty in the mechanical resistance and implant width reduction of external connection 3.5-millimeter-wide platform implants; To determine if different bone levels and crown-to-implant ratios affect the resistance to fracture of external connection 3.5-millimeter-wide platform implants with or without implantoplasty and which part of the implant is more susceptible to fracture. METHODOLOGY: Two in vitro resistance to fracture tests using 15-millimeter-long and 3.5- millimeter-wide platform implants with hexagonal external connection were conducted according to UNE-EN ISO 14801:2016. In the first test, 3 different crown-to-implant ratios (abutment heights of 7.5 millimeter (mm), 11.25mm and 15mm) were tested considering implants with 50% of bone loss. A total of 48 implants with (n=24) and without (n=24) implantoplasty were divided into 6 different subgroups. In the second resistance to fracture test, a total of 32 implants with 2 different bone loss levels (3mm; 7.5mm), with (n=16) and without implantoplasty (n=16), were analyzed. The primary outcome variable for both tests was the maximal compression force. A descriptive and bivariate analysis of the data was performed. MAIN RESULTS: Implantoplasty significantly reduced the width of the implant wall (p<0.05) in all reference points and in both experiments. The maximal compression force was significantly higher for both control and implantoplasty samples in 2:1 crown-to-implant subgroup compared with the 2.5:1 and the 3:1 samples (P<0.001). Greater bone loss also decreased the maximal compression forces, although this association was only significant for the control implants (p=0.001). Implantoplasty and control implants had similar maximal compression forces when considering the mean total values in both resistance to fracture tests. Both experiments showed that most fractures were located in the platform area. CONCLUSIONS: Implantoplasty significantly reduces implant width and this does not seem to significantly affect the resistance to fracture of external connection 3.5-millimeter wide implants. Bone loss and clinical crown-to-implant ratio seem to be more relevant variables when considering the fracture resistance of dental implants. Platform fractures are the most frequent in this test conditions.
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MORAIS LEITÃO DE ALMEIDA, Bruno alexandre. Mechanical resistance to fracture of narrow platform dental implants with hexagonal external connection submitted to implantoplasty with different bone levels and crown/implant ratios. An in vitro study.. [consulta: 30 de novembre de 2025]. [Disponible a: https://hdl.handle.net/2445/207473]