Comparison of mechanical and biological properties of zirconia and titanium alloy orthodontic micro-implants / 대한치과교정학회지

OBJECTIVE: The aim of this study was to compare the initial stability as insertion and removal torque and the clinical applicability of novel orthodontic zirconia micro-implants made using a powder injection molding (PIM) technique with those parameters in conventional titanium micro-implants. METHODS: Sixty zirconia and 60 titanium micro-implants of similar design (diameter, 1.6 mm; length, 8.0 mm) were inserted perpendicularly in solid polyurethane foam with varying densities of 20 pounds per cubic foot (pcf), 30 pcf, and 40 pcf. Primary stability was measured as maximum insertion torque (MIT) and maximum removal torque (MRT). To investigate clinical applicability, compressive and tensile forces were recorded at 0.01, 0.02, and 0.03 mm displacement of the implants at angles of 0°, 10°, 20°, 30°, and 40°. The biocompatibility of zirconia micro-implants was assessed via an experimental animal study. RESULTS: There were no statistically significant differences between zirconia micro-implants and titanium alloy implants with regard to MIT, MRT, or the amount of movement in the angulated lateral displacement test. As angulation increased, the mean compressive and tensile forces required to displace both types of micro-implants increased substantially at all distances. The average bone-to-implant contact ratio of prototype zirconia micro-implants was 56.88 ± 6.72%. CONCLUSIONS: Zirconia micro-implants showed initial stability and clinical applicability for diverse orthodontic treatments comparable to that of titanium micro-implants under compressive and tensile forces.

Submucosal zirconia implant prosthesis fabricated with CAD/CAM / 대한치과보철학회지

They have been recently introduced many aesthetic implant prosthesis using with zirconia and CAD/CAM. However, there are many limitations in their gingival and occlusal region. In this case, submucosal zirconia implant prosthesis were fabricated with CAD/CAM system. The connection of these screw cement retained prosthesis and titanium abutment was designed to 1mm above the fixture. The clinical results were satisfactory on the aesthetics and function.

Osseointegration of zirconia implant in the tibia of pigs / 대한치과보철학회지

PURPOSE: The purposes of this study were to investigate osseointegration around zirconia implants which had machined or alumina sandblasted surface, and to compare the results with titanium implants. MATERIALS AND METHODS: The study was performed on the tibia of 6 pigs. Three types of implants were investigated: group T-titanium implant, group Z-machined zirconia implant, group ZS-alumina sandblasting treated zirconia implant. Zirconia implants were manufactured from yttria-stabilized tetragonal zirconia polycrystalline (Acucera Inc., Pocheon, Korea). A total of 36 implants were installed in pigs' tibias. After 1, 4 and 12 weeks of healing period, the periotest and the histomorphometric analysis were performed. The data were analyzed using one-way ANOVA and significance was assessed by the Scheffe test (alpha=.05). RESULTS: In the measurement of surface roughness, highest Ra value was measured in group T with significant difference. No significant differences were found among groups regarding Periotest values. After 1 week, in comparison of bone to implant contact (BIC), group Z showed higher value with significant difference. In comparison of bone area (BA), group T and group Z showed higher value with significant difference than group ZS. After 4 weeks, in comparison of BIC, group T showed higher value with significant difference. Comparison of BA showed no significant difference among each implant. After 12 weeks, the highest mean BIC values were found in group T with significant difference. Group ZS showed higher BIC value with significant difference than group Z. In comparison of BA, group T and group ZS showed higher value with significant difference than group Z. CONCLUSION: Zirconia implant showed low levels of osseointegration in this experiment. Modification of surface structure should be taken into consideration in designing zirconia implants to improve the success rate.

A systematic review of zirconia as an implant material.

The purpose of this systematic review was to assess the published data concerning zirconia dental implants from various aspects. To identify relevant literature an electronic search was performed of PubMed. Titles and abstracts were screened and articles that fulfilled the inclusion criteria were selected for a full-text reading. Articles were divided into four groups: 1) studies evaluating the mechanical properties of zirconia implants, 2) studies on osseointegration of zirconia, 3) studies on peri-implant tissue response to zirconia implant, and 4) studies on plaque accumulation with zirconia. Review of the selected articles showed that zirconia implants are reliable for placement in the jaw bone. Furthermore, zirconia implants present a material surface that is compatible with the peri-implant tissue and relatively less attractive to plaque. Based on the reviewed literature, it appears that zirconia has the potential to become the dental implant material of choice, especially for aesthetic restorations; however, some issues need to be studied further.