| Objective:The rat model of peri-implantitis was established to study the effect of titanium ion on the resorption of the bone around the implant during the occurrence and development of peri-implantitis.Methods:In this experiment,the right maxillary first molar of 24 male SD rats(4-week-old)was extracted.Titanium alloy micro-implants were inserted into the alveolar crest in the edentulous area of right maxillary first molar after 4weeks of tooth extraction.osseointegration was obtained after 4 weeks.Rats that successfully achieved osseointegration were randomly divided into four groups:Control group: healthy implant group(HI group),only 20μl PBS was injected into the palatal gingival tissue of the implant neck;group A: healthy implant +titanium ion group(HI+Ti group),implant neck injection 20μl(10μg/ml)titanium ion solution;group B: peri-implantitis group(PI group),induced inflammation + 20μl PBS;group C: peri-implantitis + titanium ion group(PI+Ti group),Induce inflammation + 20μl(10μg/ml)titanium ion solution.Six rats were included in each group.Clinical morphological data and micro-CT imaging data were observed and collected at 0 and 4 weeks after researching intervention,respectively.After 4 weeks of intervention,the rats were sacrificed and the palatine gingival specimens around the implants were removed for m RNA expression analysis.The inflammation of soft tissue around the implant was evaluated through the observation of oral morphology.Micro-CT scanning of rats was performed to evaluate the changes of bone level around the implant.RT-PCR was performed to detect the m RNA relative expression of IL-1β,TNF-α,RANKL and OPG in the gingival tissues of each model group.Results:1.intraoral observation showed that the gingival tissue of the peri-implant inflammation group(PI,PI+Ti group)had redness,edema and slight exudation,while there were no obvious signs of inflammation in the healthy implant group(HI,HI+Ti group).2.Date of 0W after taking experimental intervention were set as the baseline,the data of bone level change around the implant at 4W scanned by Micro-CT.Compared with the health implant group(HI,HI+Ti group),the bone leve change of the mesial,distal,buccal and palatal sites in the peri-implantitis group(PI,PI+Ti group)were significantly increased(P <0.05),the stimulation of titanium ions did not cause significant difference in the bone level change at the mesial,distal,buccal and palatal sites around the implant(P>0.05),when HI was compared with HI+Ti group and HI was compared with HI+Ti group.3.q RT-PCR date: Compared with the m RNA expression in the health implant group(HI,HI+Ti group),the m RNA relative expression of IL-1β in the peri-implantitis group(PI,PI+Ti group)was significantly inceased.Through the comparison between HI and HI+Ti group,PI and PI+Ti group,the m RNA expression level of IL-1β in PI+Ti group is significantly higher than that in the PI group(P < 0.05),but the m RNA expression level shows no significant difference in the comparison between HI and HI+Ti group(P > 0.05).Compared with the heath implant group(HI,HI+Ti group)and peri-implantitis group(PI,PI+Ti group),the m RNA expression level of TNF-α in peri-implantitis group(PI,PI+Ti group)was significantly up-regulated(P< 0.05),but there was no significant difference of the m RNA expression of TNF-α between the HI and HI+Ti group,PI and PI+Ti group(P > 0.05).The m RNA expression level of RANKL and the RANKL/OPG ratio in peri-implantitis group(PI,PI+Ti group)was significantly up-regulated(P< 0.05),but there was no significant difference of the m RNA expression of TNF-α between the HI and HI+Ti group,PI and PI+Ti group(P > 0.05).Through comparing the HI with HI+Ti group and PI with PI+Ti group,there was no significant difference of OPG m RNA expression level among each group(P > 0.05).Conclusion:1.Titanium ion can up-regulate the expression of IL-1β m RNA during inflammation,but it has no significant effect on the expression of IL-1βm RNA in the absence of inflammation.These results suggest that titanium ions may play a synergistic role in increasing the expression of IL-1β m RNA in the gingival tissue around the implant under the existing inflammatory state and aggravating the degree of peri-implantitis.2.Titanium ions have no obvious effect on bone resorption around the implant and the m RNA expression levels of TNF-α,RANKL,and OPG in the gingival tissue,whether in an inflammatory state or a non-inflammatory state. |
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