A review of biocompatibility of zirconia and bioactivity as a zirconia implant: In vivo experiment / 대한치과보철학회지

Increasing demands for esthetic dental treatment, zirconia, which has high mechanical and esthetic properties, had been applied more and more in clinics. Therefore, assessment of biocompatibility of zirconia is necessary. In this article, a review of in vivo studies of zirconia compatibility was performed. In vivo studies showed zirconia had great biocompatibility both on soft and hard tissue. Studies with various animals and patients reported high biocompatibility of zirconia. In terms of bone synthesis and bone adhesion, zirconia showed similar biocompatible properties to titanium. On the other hand, zirconia could be used as implant. For using as an implant, various methods of Hydroxyapatite (HA) coating had been suggested. Since HA coating on titanium implant showed some problems such as low bonding strength and degeneration of HA, HA-zirconia composite, HA-coated zirconia, and HA-zirconia functionally graded material (FGM) or intermediate layer of alumina had been proposed. These methods showed higher bonding strength and biocompatibility.

Effect of different surface treatments to increase biocompatibility of dental implant / 대한치과보철학회지

STATEMENT OF PROBLEM: Modification of titanium implant surface has potential to ensure clinically favorable performance that several surface modification technologies have been introduced. Among the methods, anodizing method and sol-gel hydroxyapatite coating method have gained much interest due to its roughness and chemical composition of the coating layer, but more of its biocompatibility result is required. PURPOSE: The purpose of this study was to compare bone-implant interface shear strength of four different surface treated implants as time elapsed. Resonance frequency analysis(RFA) and removal torque measurement methods were employed to measure implant stability at one week and six week after implantation. MATERAL AND METHOD: A total of 80 screw-shaped implant [20 machined, 20 resorbable media blasted(RBM), 20 anodized, and 20 anodized+hydroxyapatite sol-gel coated] were prepared, and one of each group was implanted in the tibia of a New Zealand white rabbit that total 20 of them were used. In order to test the implant stability and implant-tissue interface contact changing in the bone bed, each 10 rabbit were sacrificed 1 week and 6 week later while resonance frequency and removal torque were measured. One-way analysis of variance and the Tukey test were used for statistical analysis. RESULTS: The results were as follows. 1. There was no statistically significant difference of implant stability quotients(ISQ) value in RFA between individual groups after 1 week of implantation and 6 weeks(p>0.05). But, there was statistically significant increase of ISQ value in 6 weeks group compared to 1 week group(p0.05), but there was statistically significant increase in all 4 groups after 6 weeks compared to 1 week later(p 0.05), but significant difference was appeared in both groups compared to RBM group and smooth-machined group (p< 0.05). CONCLUSIONS: It can be suggested that changes in surface characteristics affect bone reactions. Anodized and anodized+hydroxyapatite sol-gel coating showed significantly improved bone tissue response to implants, but further study on the effect of hydroxyapatite dissolution is needed.

The Results of Hip Arthroplasty with Hydroxyapatite Coated Anatomical Profile(R) Femoral Stem: Result After 5-Years to 10-years Follow up / 대한정형외과학회잡지

PURPOSE: To report the results of hip arthroplasty using an uncemented hydroxyapatite (HA) coated anatomical Profile(R) femoral stem during a follow-up period of five to ten years. MATERIALS AND METHODS: Eighty-eight patients, ninety-nine cases of hip arthroplasty, who underwent surgery from May 1993 to February 1998, were reviewed clinically and radiographically. RESULTS: The mean Harris hip rating score was 54.4 preoperatively, which improved to 88.2 at the last follow up postoperatively. The radiographic evaluations revealed that endosteal new bone formation developed at Gruen zone 1 and 7 in all cases (100%) between 6 month and one year after surgery. Approximately 20 cases (20%) showed proximal osteoporosis due to profound stress shielding, and 83 cases (83.8%) showed distal cortical hypertrophy (zone 2, 6). These femoral remodelings correlated with the clinical results statistically. There was no aseptic loosening, but the polyethylene liner was changed only in one hip due to severe liner wear. CONCLUSION: This study indicate that the anatomical Profile(R) femoral stem can provide excellent initial stability and osseointegration. However, profound proximal bone loss was noted secondary to distal cortical hypertrophy in the long-term follow up. Therefore, other design concepts are needed, in which the femoral strain transfers more proximally rather than distally.