Marijuana smoke decreases bone filling around titanium implants in rats

Objectives: Although a harmful effect of tobacco smoking on titanium implants has been documented, no studies have investigated the effects of marijuana smoking. Thus, this study histologically investigated whether marijuana smoke influences bone healing around titanium implants comparing to THC levels in urine. Methods: Twenty-two male Wistar rats received titanium implants in the tibias and were randomly assigned to one of two groups: CTRL-control group (N = 11) and CS-cannabis sativa smoke inhalation throughout the entire 60-day experiment (N = 11). Urine samples from all animals were taken at the end of the 60-day experimental period to verify the presence of tetra-hidro-cannabinoid (THC) levels. The animals were killed and the degree of bone-to-implant contact (BIC) and the bone area (BA) within the limits of the implant threads obtained for cortical (zone A) and cancellous bone (zone B). Results: The THC levels in urine were positive only for nine rats (n=9/CS group) and negative for 13 rats (n=11/CTRL and n=3/CS group). Then, for the histological analysis the three negative animals from CS were eliminated. Inter-group analysis (Kruskal-Wallis test, alpha = 0.05) demonstrated a significant effect of CS on BA and BIC (P <0.05) compared to control group values (P >0.05): 88.22% +/- 6.34% and 55.35% +/- 5.45% in zone A, and 51.67% +/- 7.33% and 28.89% +/- 8.97% in zone B for groups CTRL and CS respectively. Conclusion: Considering the limitations of the present study, marijuana smoke inhalation has a deleterious effect on cortical and cancellous bone healing around titanium implants.(FAPESB#2003)