ABSTRACT
BACKGROUND: Some studies have shown that topical application of zoledronic acid and topical application of silver nanoparticles can promote bone formation, but the difference between two methods has not been reported. OBJECTIVE: To investigate the effect of topical application of zoledronic acid versus topical application of silver nanoparticles on rabbit tooth extraction socket immediate implantation of titanium screw bonding. METHODS: Twenty-four New Zealand white rabbits were randomly divided into zoledronic acid and silver nanoparticles groups (n=12/group). After removing four incisors of the upper and lower jaws, the mixture of nanometer silver and nanometer hydroxyapatite and nanometer zoledronic acid hydroxyapatite were respectively filled in the tooth extraction pit of the two groups, and titanium screw was implanted at the same time. The isolated specimens of the upper and lower mandibles were taken at 4, 8 and 12 weeks after surgery. The data reflecting the osseointegration around the implant were obtained through gross observation, torque test, bone density test and histomorphological observation. The study was approved by the Ethical Committee of the Third Hospital of Hebei Medical University in December 2015, approval No. Z2015-021-1. RESULTS AND CONCLUSION: (1) The test results of torque mechanics showed that the average torque peak value of all titanium nails increased with the extension of time (the average value of torque peak value) and reached the maximum value at 12 weeks (the average value of torque peak value). At 4, 8 and 12 weeks after surgery, the torque peak value of titanium screw in the zoledronic acid group was higher than that in the silver nanoparticles group, and the stability of titanium screw in zoledronic acid group was better than that in silver nanoparticles group, but the difference was insignificant (P>0.05). (2) General observation and histological observation showed that at 4, 8 and 12 weeks after surgery, the hardness and structure of bone around the implants in the zoledronic acid group were significantly better than those in the silver nanoparticles group. (3) Bone mineral density analysis results showed that, at 4, 8 and 12 weeks after surgery, the gray value of bone tissue around the titanium screw in the zoledronic acid group was higher than that in the silver nanoparticles group at the same period (P>0.05). (4) These results suggest that the osseointegration of immediate implantation using nanometer zoledronic acid hydroxyapatite is better than that of the mixture of nanometer silver and nanometer hydroxyapatite.
ABSTRACT
Objective:To compare the alveolar cortical bone density and thickness of jaw bones between teenagers (12-18 years of age) and adults(19-48 years of age).Methods:Spiral computed tomographic images of 60 cases were obtained from the subjects with the ages of 12 to 48 years(27 Males and 33 females,35 teenagers and 25 adults).Buccal cortical bone thickness and density in Hounsfield units were measured at 12 interradicular sites and to a depth of 14 mm.Results:The alveolar cortical bone thicknesses and densities of the jaw bones significantly increased from the crest to base of alveolar crest.The average cortical bone thicknesses rangedfrom 1.0 to 1.5 mm in the anterior part of the jaw bones,1.1 to 1.8 mm in maxillary posterior area and 1.5 to 2.8 mm in the mandible posterior areas.The cortical bone thickness and density were greater in the mandible than in the maxilla(P ＜ 0.05).The thickness values did not show difference between males and females,between adolescents and adults.Higher values of bone density were found in the adults than in the teenagers(P ＜0.05).The highest bone density in the mandible posterior area of adults was observed,and the lowest bone density in the maxillary posterior area of adolescents.Conclusion:Alveolar cortical bone density of adolescents is lower than that of adults,especially in the maxilla posterior region.
ABSTRACT
BACKGROUND: Based on a mouse model of tibial implantation, some scholars have found that the CaP-coated implant with recombinant human parathyroid hormone (1-34) (PTH(1-34)) shows strong osteogenesis effect at early stage, but this coating has not been applied in the oral environment.OBJECTIVE: To explore the role of local application of PTH(1-34) on immediate implant osseointegration . METHODS: Nine New Zealand white rabbits were randomly divided into two groups (six in experimental group and three in control group). All of the tooth sockets were filled with heterogeneous freeze-dried bone firstly after four incisors of each rabbit were extracted. In the experimental group, a titanium screw with PTH(1-34) loaded CaP coating was implanted into each tooth socket, while in the control group, a titanium screw with only CaP coating was implanted. The animals were executed respectively at 4, 8, 12 weeks after operation, and the intact maxillary and mandibular specimens were harvested and tested by gross observation, bone density analysis, torque test, histologic al observation, X-ray observation.RESULTS AND CONCLUSION: The gray value and maximum torque value of regenerated osseous tissue at different time points in the experimental group were significantly higher than those in the control group (P < 0.05). Within 4-12 weeks after implantation, regenerated and mature bone tissue appeared earlier in the experimental group than the control group. A large amount of new blood vessels were seen in the experimental group at 8 weeks after implantation, while in the control group, there were only few new blood vessels. To conclude, the local application of PTH(1-34) can promote bone formation, improve the implant-bone bonding strength, and enhance the stability of the implant.
ABSTRACT
BACKGROUND:Nanosilver has significant antibacterial properties, and nanohydroxyapatite has good biological activity and mechanical strength, while their mixture cannot only promote bone formation but also have antibacterial properties. OBJECTIVE:To observe the effect of nanosilver and nanohydroxyapatite mixed filing on the osseointegration of immediate implants. METHODS: Nine New Zealand white rabbits were randomly divided into experimental group (n=6) and control group (n=3) after four incisors from the upper and lower jaw were extracted. The mixture of nanosilver and nanohydroxyapatite was filed into the tooth socket in the experimental group, while nanohydroxyapatite was filed into the tooth socket in the control group. Titanium screw was immediately implanted into both groups. The intact maxila and mandibular specimens were harvested at the 4th, 8th, and 12th weeks after operation. Gross observation, X-ray bone density analysis, torque test and histological observation were conducted. RESULTS AND CONCLUSION:The gray value and maximum torque value of regenerated osseous tissue at different time points in experimental group were significantly higher than those in the control group (P < 0.05). Within 12 weeks of implantation, the bone formation rate and maturity of new bone tissue were higher in the experimental group compared with the control group, and no inflammatory cel infiltration occurred. At the 4th week after implantation, there was a large amount of inflammatory cel infiltration, and few inflammatory existed at the 8th week after implantation. These results demonstrate that compared with nanohydroxyapatite alone, the mixture of nanosilver and nanohydroxyapatite shows better antibacterial effect, biocompatibility and osteoinductive ability, which may accelerate osseointegration and promote osteogenesis.