Yun-Young Chang1, Su-Hwan Kim2, Keun-Oh Park3, Jeong-Ho Yun4,5. 1. Division of Periodontology, Department of Dentistry, Inha International Medical Center, Incheon, Korea. 2. Department of Periodontics, Asan Medical Center & Department of Dentistry, University of Ulsan College of Medicine, Seoul, Korea. 3. Department of Bio-fibers and Materials Science, Kyungpook National University, Daegu, Korea. 4. Department of Periodontology, School of Dentistry and Institute of Oral Bioscience, Chonbuk National University, Jeonju, Korea. 5. Research Institute of Clinical Medicine of Chonbuk National University-Biomedical Research Institute of Chonbuk National University Hospital, Jeonju, Korea.
Abstract
OBJECTIVES: The objective of this study was to investigate the effect of microthreads on the coronal bone healing of narrow-diameter implants with reverse-tapered design. MATERIAL AND METHODS: A total of 52 implants were classified into two groups according to presence or absence of coronal microthreads, the reverse-tapered narrow-diameter implant (RTN) group, and the reverse-tapered narrow-diameter implant with microthreads (RTNM) group. The implants were installed in split-mouth design in the edentulous mandible of six dogs. Three animals were sacrificed at 4 weeks and three at 8 weeks. Resonance frequency analysis, bone measurement using microcomputed tomography (micro-CT), removal torque test, and histometric analysis were performed. RESULTS: No significant differences in implant stability quotient value were observed between the groups at baseline, 4 weeks, or 8 weeks. Bone measurement using micro-CT showed that bone-implant contact volume (BICV) and bone-implant contact volume ratio (BICVR) in the coronal part of RTNM were statistically higher than those in RTN at 4 and 8 weeks. Histometric analysis showed statistically higher bone-implant contact length (BICL) in the coronal part of RTNM than in RTN at 4 weeks; however, bone-implant contact ratio (BICR) was not significantly different between the groups. At 8 weeks, the BICL and BICR did not differ significantly between the groups. Removal torque test showed no significant differences between the groups at 4 and 8 weeks. CONCLUSIONS: The microthreads might facilitate more coronal bone-implant contact due to increased surface areas at an early healing phase; however, they did not significantly affect coronal bone healing at 8 weeks.
OBJECTIVES: The objective of this study was to investigate the effect of microthreads on the coronal bone healing of narrow-diameter implants with reverse-tapered design. MATERIAL AND METHODS: A total of 52 implants were classified into two groups according to presence or absence of coronal microthreads, the reverse-tapered narrow-diameter implant (RTN) group, and the reverse-tapered narrow-diameter implant with microthreads (RTNM) group. The implants were installed in split-mouth design in the edentulous mandible of six dogs. Three animals were sacrificed at 4 weeks and three at 8 weeks. Resonance frequency analysis, bone measurement using microcomputed tomography (micro-CT), removal torque test, and histometric analysis were performed. RESULTS: No significant differences in implant stability quotient value were observed between the groups at baseline, 4 weeks, or 8 weeks. Bone measurement using micro-CT showed that bone-implant contact volume (BICV) and bone-implant contact volume ratio (BICVR) in the coronal part of RTNM were statistically higher than those in RTN at 4 and 8 weeks. Histometric analysis showed statistically higher bone-implant contact length (BICL) in the coronal part of RTNM than in RTN at 4 weeks; however, bone-implant contact ratio (BICR) was not significantly different between the groups. At 8 weeks, the BICL and BICR did not differ significantly between the groups. Removal torque test showed no significant differences between the groups at 4 and 8 weeks. CONCLUSIONS: The microthreads might facilitate more coronal bone-implant contact due to increased surface areas at an early healing phase; however, they did not significantly affect coronal bone healing at 8 weeks.