A radiographic comparison of progressive and conventional loading on crestal bone loss and density in single implants

Crestal bone loss is a biologic complication in implant dentistry. The aim of this study was to compare the effect of progressive and conventional loading on crestal bone height and bone density around single osseointegrated implants in posterior maxilla by a longitudinal radiographic assessment technique. Twenty micro thread implants were placed in 10 patients (two implants per patient). One of the two implants of each patient was assigned to progressive and the other to conventional loading groups. Eight weeks after surgery, conventional implants were restored with a metal ceramic crown and progressive group underwent a progressive loading protocol. The progressive loading group takes different temporary acrylic crowns at 2, 4 and 6 months. After eight months, acrylic crowns were replaced with metal ceramic crown. Computer radiography of both progressive and conventional implants was taken at 2, 4, 6, and 12 months. Image analysis was performed to measure height of crestal bone loss and bone density. The mean values of crestal bone loss at month 12 were 0.11 (0.19) mm for progressively and 0.36 (0.36) mm for conventionally loaded implants, with a statistically significant difference (P < 0.05) using Wilcoxon sign rank. Progressively loaded group showed a trend for higher bone density gain compared to conventionally loaded group but when tested with Repeated measure ANOVA, the differences were not statistically significant (P > 0.05). Progressive group showed less crestal bone loss in single osseointegrated implant than conventional group. Bone density around progressively loaded implants showed increase in crestal, middle and apical.