Effects of Bisphosphonates on Osseointegration of Dental Implant

Abstract

Objectives: To assess the osseointegration of dental implants with or without bisphosphonates treatment.

Methods: Twenty female New Zealand White rabbits were used in this study. Zoledronic acid (ZA groups) or saline (control groups) were administrated 3 times per week (0.1mg/kg, s/c) for 4 weeks before implant insertion. The implant was placed on the calvarial bone and covered with a resorbable membrane. After surgery, ZA or saline was given for 4 weeks (short-term groups) or 8 weeks (long-term groups). Three types of fluorochrome labelling solutions (FLS) were injected subcutaneously in sequence at week 1, 2 and 3 post-surgery for the short-term groups, and at week 2, 4, 6 post-surgery for the long-term groups. Animals were sacrificed 4 weeks or 8 weeks post-operatively according to their grouping. Collected samples were processed for Micro-CT, confocal microscope and histology analysis.

Results: Micro-CT examination showed that both ZA treated groups had higher BV/TV, BMD, Tb.Th., Tb.N and lower Tb.Sp than their control counterparts. However, the differences were not significant. The distances between two serial fluorochrome labelling were measured. The average bone growth rates were calculated by dividing the distance by the amount of days in between two sequenced FLS injections. Both long- and short-term ZA treated groups demonstrated markedly reduced bone growth rates.

Conclusions: The effect of the bisphosphonates decreased the bone growth rates during the whole experiment period, and this effect seemed to be even stronger in the first 1-2 weeks after implant insertion in the bisphosphonates treated rabbits. Other results are still under investigations.

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