Histological and scanning electron microscopy investigation of the effects of titanium surface modifications on osseointegration in rabbits

Abstract

Objective: This study aimed to compare the novel Estaş Medical Anodization (EMA) surface treatment technique with the techniques commonly used in the literature and to examine their effects on osteointegration in the rabbit tibia. Methods: A total of 24 rabbits used in this study were divided into 3 groups, with 8 rabbits in each group. Using both tibias of all rabbits in the study, screws belonging to the control group were placed in the left tibia, and the right tibia belonging to the experimental group were placed. In the first 8 rabbits, a single experimental group in the right tibia were used; in the second 8 rabbits, 2 different experimental groups in the right tibia were used; and in the last 8 rabbits, 2 different experimental groups in the right tibia were used. Thus, 5 different experimental groups with 8 screws in each group and a separate control group were formed for each of them. EMA-treated surfaces were named 200-800 nm iris oxidation and 800-1200 nm gray oxidation according to the TiO2 layer thickness. Group 1 was implanted with mini-screws prepared with chemical etching+EMA iris oxidation, while group 2 was implanted with sandblasted, large-grit and acid-etched (SLA) mini screws treated with EMA gray oxidation. Group 3 was implanted with mini-screws treated with EMA gray oxidation, group 4 was implanted with mini-screws treated with chemical etching+micro-arc oxidation, and group 5 was implanted with mini-screws treated with chemical etching+EMA gray oxidation. The control group was implanted with mini-screws prepared with pure titanium. At the end of 6 weeks, osseointegration percentages were calculated and compared using histological and scanning electron microscope (SEM) analyses. Results: The histological results confirmed the increase in osseointegration percentages in all experimental groups compared to those that received pure titanium implants (P values control group vs group 1=.005, control group vs group 2, 3, 4, 5=.001). The comparison between the groups revealed that the chemical etching+EMA gray oxidation modification technique (group 5) significantly increased osseointegration compared to the SLA+EMA gray oxidation technique (group 5 vs group 2 P=.016) and the chemical etching+EMA iris oxidation technique (group 5 vs group 1 Pp=.001). The EMA gray oxidation technique (group 3) significantly increased osseointegration compared to the chemical etching+EMA iris oxidation technique (group 1) (group 3 vs group 1 P=.043). The results of the SEM analysis showed that osseointegration was significantly increased in all experimental groups compared to that in the pure titanium (control) group (P values control group vs group 1, 2, 3=.001, control group vs Group 4,5=.006). The mean osseointegration percentage in the experimental groups was the highest in group 5, followed by group 4, group 3 and group 1 equally, and group 2. However, the differences among the experimental were not significant (group 1, group 2, group 3, group 4 vs group 5 P=.408). Conclusion: The EMA titanium surface modification techniques we developed significantly increased osseointegration compared to the pure titanium surface. The EMA gray oxidation technique seems to result in higher osseointegration rates than the EMA iris oxidation technique, and similar rates can be found with the SLA and chemical etching techniques. Level of Evidence: N/A.