Effect of the Acid-Etching on Grit-Blasted Dental Implants to Improve Osseointegration: Histomorphometric Analysis of the Bone-Implant Contact in the Rabbit Tibia Model

Abstract

Previous studies have shown that the most reliable way to evaluate the success of an implant is by bone-to-implant contact (BIC). Recent techniques allow modifications to the implant surface that improve mechanical and biological characteristics, and also upgrade osseointegration. Objective: The aim was to evaluate the osseointegration in rabbit tibia of two different titanium dental implant surfaces: shot-blasted with Al2O3 (SB) and the same treatment with an acid-etching by immersion for 15 s in HCl/H2SO4 (SB + AE). Material and methods: Roughness parameters (Ra, Rt, and Rz) were determined by white light interferometer microscopy. Surface wettability was evaluated with a contact angle video-based system using water, di-iodomethane, and formamide. Surface free energy was determined by means of Owens and Wendt equations. Scanning electron microscopy equipped with X-ray microanalysis was used to study the morphology and determine the chemical composition of the surfaces. Twenty-four grade 4 titanium dental implants (Essential Klockner®) were implanted in the rabbit’s tibia, 12 for each surface treatment, using six rabbits. Six weeks later the rabbits were sacrificed and the implants were sent for histologic analysis. Resonance frequency analysis (RFA) was recorded both at the time of surgery and the end of the research with each device (Osstell Mentor and Osstell ISQ). Results: The roughness measurements between the two treatments did not show statistically significant differences. However, the effect of the acid etching made the surface slightly more hydrophilic (decreasing contact angle from 74.7 for SB to 64.3 for SB + AE) and it presented a higher surface energy. The bone-to-implant contact ratio (BIC %) showed a similar tendency, with 55.18 ± 15.67 and 59.9 ± 13.15 for SB and SB + AE implants, respectively. After 6 weeks of healing, the SB + AE showed an implant stability quotient (ISQ) value of 76 ± 4.47 and the shot-blasted one an ISQ value of 75.83 ± 8.44 (no statistically significant difference). Implants with different surface properties had distinctive forms of behavior regarding osseointegration. Furthermore, the Osstell system was an invasive and reliable method to measure implant stability. Conclusion: Both surfaces of implants studied showed high osseointegration. The SB and SB + AE implants used in our study had similar behavior both in terms of BIC values and RFA. The RFA systems in Osstell Mentor and Osstell ISQ confirmed nearly perfect reproducibility and repeatability.

Comparison of Osseointegration of Dental Implants Placed in Rabbit Tibia Using Two Dental Laser and Implant Handpiece Systems

“…Although the measurement of implant stability through micro-CT or ISQ is non-invasive, it has the disadvantage that osseointegration cannot be confirmed as directly as histological investigation. Histological BIC ratio in the present study was similar to that of other studies (35.16% by Kfouri et al [ 29 ], 45.2% by Yeo et al [ 32 ] and 59.9% by Rios-Carrosco et al [ 33 ]), and histological observations confirmed that proper osseointegration was gained, directly. However, compared to micro-CT or ISQ measurement, histological observation has a limitation that the result value may be different depending on which part is used as a sample, so the results should be interpreted with caution.…”

“…Both groups showed significant intragroup differences in the ISQ values measured immediately after implant placement, and at one month after implant placement, indicating that osseointegration progressed adequately at one month after implant placement in both groups. The ISQ values measured after 6 weeks were similar to those of other studies (68~70 by Yeo et al [ 32 ] and 73~78 by Rios-Carasco et al [ 33 ]), and through this, proper implant stability to withstand loading was achieved. Immediately after surgery, a higher ISQ value was noted in the experimental group than in the control group; however, at one month after surgery, both groups showed similar ISQ values.…”

Effect of the Nature of the Particles Released from Bone Level Dental Implants: Physicochemical and Biological Characterization

“…This surface generally presents important residual stress values due to the impact of the abrasive particles that have caused plastic deformation on the surface. The stresses suffered in these areas due to friction between the cortex and the implant cause the release of particles that fracture the surface of the dental implant [5,6].…”