بررسي راديوگرافيك اثر بارگذاري تدريجي بر روي تغييرات استخوان كرستال و تراكم استخوان اطراف ايمپلنت هاي تك واحدي خلف ماگزيلا

A radiographic evaluation of progressive loading on crestal and bone density changes around single osseointegrated implants in the posterior maxilla

Background and Aim: The aim of this clinical study was to determine the effectiveness of progressive loading procedures on preserving crestal bone height and improving peri-implant bone density around maxillary implants restored with single crowns by an accurate longitudinal radiographic assessment technique. Materials and Methods: Eleven Micro-Thread Osseo Speed dental implants were placed in 11 subjects and permitted to heal for 6 weeks before surgical uncovering. Following an 8-week healing period, implants underwent a progressive loading protocol by increasing the height of the occlusal table in increments from adding acrylic resin to an acrylic crown. The progressively loaded crowns were placed in 2 mm infraocclusion for the first 2 months, light occlusion for the second 2 months, and full occlusion for the third 2 months. At forth 2 months, a metal ceramic crown replaced the acrylic crown. Digital radiographs of each implant were made at the time of restoration, then after 2, 4, 6, 8, and 12 months of function. Digital image analysis was done to measure changes in crestal bone height and peri-implant bone density. Results: The mean values of crestal bone loss at 12 months were 0.11 ±0.19 mm, and when tested with Friedman across the time periods, the differences were not statistically significant (p> 0.05). The mean values of bone density in the crestal, middle, and apical area were tested with Repeated Measure ANOVA across the time periods, the differences were statistically significant (p<0.05). Conclusion: Progressive loading doesnʹt cause crestal bone loss. The peri-implant density measurements of the progressively loaded implants show continuous increase in crestal, middle and apical peri-implant bone density by time.