ABSTRACT
BACKGROUND: Crestal bone loss known as saucerization is a frequently observed phenomenon. Recent studies have shown that implants with micothreaded crest module reduced the force concentration in the crestal region thus resulting in no or reduced crestal bone loss. This study presents a clinical, histologic, and histometric evaluation of implants with microthreaded crest module and SLA surface. METHODS: The implants were placed in the mandible of 5 beagle dogs weighing 10-15kg. Four premolars were bilaterally extracted 8 weeks prior to implant placement. Mucoperiosteal flap was elevated and drilling with increasing diameter was performed under saline irrigation. After countersinking 2 implants were placed in each side resulting in 4 implants per dog. Healing period of 8 weeks was allowed before sacrificing the animals. Histologic preparation was performed for histologic and histometric analysis. Bone to implant contact as well as percentage of bone area inside threads were measured. T-test was used for statistical analysis with pvalue p<0.05. RESULTS: 1. Healing was uneventful without any cover screw exposure. New bone formation around the implants was observed without any inflammatory infiltration. 2. Bone to implant contact in the microthread and thread were 43.90 +/- 20.30 %, and 53.19 +/- 20.97 % respectively. The overall bone to implant contact was 48.54 +/- 20.95 %. 3. Percentage of bone area inside threads were 54.43 +/- 10.39 %, and 38.44 +/- 16.44 % for the microthread and thread respectively. There was statistically significant difference(p<0.05). The overall percentage of bone area inside threads was 46.67 +/- 15.68 %.
Subject(s)
Animals , Dogs , Bicuspid , Mandible , OsteogenesisABSTRACT
Since the occlusal loading is transmitted to the surrounding bone, the success of an implant treatment is closely related to the distribution of the stress on the implant. The finite element analysis method is often used in order to produce a model for dispersion of stress. Assessment of the success of the implant is usually based on the degree of osseointegration which is a bone and implant surface interface. Implant used in this research was designed through the method of shape optimization after the stress on implant was anaylzed by the finite element analysis method. This study was pertinently assessed by a clinical, histologic, histomorphometric analysis after the shape optimized implant was installed on beagle dog tibia. The results are as follows 1. It clinically showed a good result without mobility and imflammatory reaction. 2. Implant was supported by dense bone and bone remodeling showed on the surrounding area of the implant 3. The average percentage of bone-implant contact was 58.1%.The percentage of bone density was 57.6%. Having above results, shape optimized implant showed the pertinence through clinical and histologic aspects. However, to use the shape optimized implant, the further experiment is required for finding problems, improvement.
Subject(s)
Animals , Dogs , Bone Density , Bone Remodeling , Finite Element Analysis , Osseointegration , TibiaABSTRACT
BACKGROUND: This study presents a biomechanical and histometric comparison of bone response to implants with various area of hydroxyapatite(HA) coating. METHODS: The implants were placed in the tibia of 10 rabbits weighing 2.5-3.5kg. The control group had a machined surface, the experimental group 1 had 50micrometer thick HA coated in a band form, and the experimental group 2 had 50micrometer thick HA coated on the entire surface. 8 weeks after implantation, the animals were sacrificed. Removal torque was measured and histologic preparation was also performed for histologic and histometric analysis. Bone to implant contact as well as percentage of bone area inside threads were measured. ANOVA post hoc, and t-test were used for statistical analysis with p-value p<0.05. RESULTS: 1. The removal torques were 9.36 +/- 5.64 Ncm, 48.40 +/- 16.66 Ncm, and 82.37 +/- 22.56 Ncm for the control, exp. 1, and exp. 2 group respectively. Statistically significant difference were found among all the groups(p<0.05). 2. Bone to implant contact in the cortical bone were 38.94 +/- 10.9 %, 66.90 +/- 14.1 %, 73.00 +/- 19.4 %, in the marrow bone, 8.30 +/- 5.4 %, 14.59 +/- 5.9 %, 18.54 +/- 11.8 %, and in total, 22.40 +/- 10.1 %, 31.19 +/- 7.5 %, 41.41 +/- 12.2 % for the control, exp.1, and exp. 2 group respectively . In the cortical bone, exp. 1, and exp. 2 group showed statistically significantly higher contact compared to control group. Total contact and in the marrow bone, only exp. 2 group showed statistically significantly higher contact compared to control group(p<0.05). In all the groups significantly higher contact were observed in the cortical bone compared to the marrow bone(p<0.05). 3. Percentage of bone area inside threads in the cortical bone were 55.68 +/- 7.25 %, 55.19 +/- 13.19 %, 57.04 +/- 13.33 %, in the marrow bone, 12.34 +/- 14.61 %, 17.56 +/- 20.04 %, 20.26 +/- 12.83 %, and in total, 30.30 +/- 12.46 %, 31.57 +/- 15.15 %, 34.25 +/- 12.56 % for the control, exp.1, and exp. 2 group respectively. There was no statistical difference among the groups. In all the groups significantly higher bone area were observed in the cortical bone compared to the marrow bone(p<0.05)