The influence of systemically administered oxytocin on the implant-bone interface area: an experimental study in the rabbit

PURPOSE: The purpose of this study was to assess the effect of systemically administered oxytocin (OT) on the implant-bone interface by using histomorphometric analysis and the removal torque test. MATERIALS AND METHODS: A total of 10 adult, New Zealand white, female rabbits were used in this experiment. We placed 2 implants (CSM; CSM Implant, Daegu, South Korea) in each distal femoral metaphysis on both the right and left sides; the implants on both sides were placed 10 mm apart. In each rabbit, 1 implant was prepared for histomorphometric analysis and the other 3 were prepared for the removal torque test (RT). The animals received intramuscular injections of either saline (control group; 0.15 M NaCl) or OT (experimental group; 200 microg/rabbit). The injections were initiated on Day 3 following the implant surgery and were continued for 4 subsequent weeks; the injections were administered twice per day (at a 12-h interval), for 2 days per week. RESULTS: While no statistically significant difference was observed between the two groups (P=.787), the control group had stronger removal torque values. The serum OT concentration (ELISA value) was higher in the OT-treated group, although no statistically significant difference was found. Further, the histomorphometric parameter (bone-toimplant contact [BIC], inter-thread bone, and peri-implant bone) values were higher in the experimental group, but the differences were not significant. CONCLUSION: We postulate that OT supplementation via intramuscular injection weakly contributes to the bone response at the implant-bone interface in rabbits. Therefore, higher concentrations or more frequent administration of OT may be required for a greater bone response to the implant. Further studies analyzing these aspects are needed.

The influence of intentional mobilization of implant fixtures before osseointegration / 대한치과보철학회지

PURPOSE: The purpose of this study was to investigate the influence of mobilization on bone-implant interface prior to osseointegration of fixtures. MATERIALS AND METHODS: The experimental implants (3.75 mm in diameter, 4.0 mm in length) were made of commercially pure (Grade IV) titanium, and were treated with RBM (MegaGen(R): Ca-P). The 80 implants (two in each tibia) were inserted into the monocortical tibias of 20 rabbits which each weighed more than 3.5 kg (Female, New Zealand White). According to the removal torque interval, the groups were divided into 10 groups, Group I (6 wks), Group II (4 days + 6 wks), Group III (4 days + 1 wk + 6 wks), Group IV (1 wk + 6 wks), Group V (1 wk + 1 wk + 6 wks), Group VI (2 wks + 6 wks), Group VII (2 wks+ 1 wk + 6 wk), Group VIII (3 wks + 6 wks), Group IX (3 wks + 1 wk + 6 wks) and Group X (10 wks). The control groups were Group I and X, the removal torque was measured at 6 wks and 10 wks with a digital torque gauge (Mark-10, USA). In the experimental groups, the removal torque was given once or twice before the final removal torque and the value was measured each time. After which, the implants were put back where they had been except the control groups. All the experimental groups were given a final healing time (6 wks) before the final removal torque test, in which values were compared with the control groups and the 1st and/or 2nd removal torque values in each experimental group. RESULTS: In the final removal torque tests, the removal torque value of Group X (10 wks) was higher than that of Group I (6 wks) in the control groups but not statistically different. There were no significant differences between the experimental groups and control groups (P>.05). In the first removal torque comparison, the experimental groups (4 days or 1 wk) values were significantly lower than the other experimental groups (2 wks or 3 wks). In the comparison of each experimental group according to healing time, the final removal torque value was significantly higher than the 1st torque test value. CONCLUSION: Once or twice mobilization of fixture prior to osseointegration did not deter the final bone to implant osseointegration, if sufficient healing time was given.

Osseointegration with Ceramic Coated Implant / 대한척추외과학회지

PURPOSE: This study was designed to clarify the osseointegration of the titanium screw coated with CMP, in regard to the time schedule, through the characteristic of early osseointegration. MATERIALS AND METHODS: Mechanical, radiological and histomophometric measurements were performed in 28 rabbit tibial proximal metaphyseal cortical bone screws 6, 12, 26 and 52 weeks after surgery for the in vivo comparison of the osseointegration of titanium screws (3.75 mm diameter, 5 mm length) with different surface treatments: CMP coating group, with the sol-gel method (experimental group) and uncoated group (control group). RESULTS: 1. Radiology: There were no differences between the two groups without a radiolucent line or in regard to the time schedule. 2. Histology: There were no differences between the two groups without a fibrous tissue intervening surface or in regard to the time schedule. 3. Torque test: The test results for the CMP coated group were 1.5 times higher than those for the uncoated group, which was statistically meaningful, but there was no difference in regard to the time schedule. CONCLUSION: CMP coating is an option to increase the osseointegration of the titanium screw.