Influence of nicotine administration on different implant surfaces: a histometric study in rabbits

This study investigated the influence of implant surface on osseointegration around titanium implants inserted in the tibiae of rabbits administered with nicotine.

Thirty-two (32) New Zealand rabbits were included in the study. After anesthesia, the tibia surface was exposed and 2 screw-shaped commercially available pure titanium implants 7.0 mm in length and 3.75 mm in diameter were placed bilaterally. A total of 128 implants were inserted: 64 blasted with Al2O3 particles (Group 1) and 64 with a machined surface finish (Group 2). The animals were randomly assigned to 1 of 4 treatment subgroups, and daily subcutaneous injections of nicotine were administered: A) saline solution; B) 0.37 mg/kg; C) 0.57 mg/kg; and D) 0.93 mg/kg. In order to label regenerated bone, a 2% calcein green solution was administered by intramuscular injection at 0, 7, and 15 days after implant insertion. After 42 days, the animals were sacrificed and undecalcified sections were prepared. The degree of bone contact with the implant surface, the bone area, and the intensity of bone labeling were measured into the limits of the implant threads.

Statistical analysis (2-way ANOVA) revealed no significant difference regarding the effect of nicotine on bone healing around the implants (P>0.05). However, a significant influence of the implant surface on the degree of bone-to-implant contact was detected in groups C (30.13 +/- 4.97 and 37.85 +/- 8.85, for machined and Al2O3-blasted surfaces, respectively) and D (27.79 +/- 3.93 and 33.13 +/- 8.87, for machined and Al2O3-blasted surfaces, respectively) (P<0.05).

Although nicotine administration may not statistically influence bone healing around titanium implants, implant surface design may enhance osseointegration after nicotine administration.