Zirconia with laser‐modified microgrooved surface vs. titanium implants covered with melatonin stimulates bone formation. Experimental study in tibia rabbits

Objectives The aim of the study was to evaluate if zirconia implants with micro‐grooved surfaces supplemented with melatonin enhance the bone‐to‐implant contact ( BIC ) vs. titanium implants with the same coating. Materials and methods Eighty implants divided in four groups were inserted in the tibia of 20 New Zealand rabbits as follows: (group A) 20 titanium implants; (group B) 20 micro‐grooved zirconia implants; (group C) 20 titanium implants supplemented with melatonin and (group D) 20 micro‐grooved zirconia implants supplemented with melatonin. Histometric and SEM evaluation of BIC were evaluated after 1 and 4 weeks. Results At 1 week, group C (29.7 ± 2.4%) and group D (28.9 ± 1.3%) implants showed higher BIC % compared with group A and B ( P  < 0.05). After 4 weeks, group D showed higher BIC compared with all the groups (47.5 ± 2.2%) ( P  < 0.05). Also Connective tissue was higher in groups B (78.9 ± 2.1%) and D (88.7 ± 1.2%) related to titanium and zirconia melatonin untreated at 4 weeks ( P  < 0.05). Conclusions Within the limitations of this pilot study in rabbits, we can conclude that the local application of melatonin increases the BIC values in titanium and in zirconia implants at 1 week.