Efficacy of local minocycline agents for treating peri-implant mucositis and peri-implantitis in dogs- in vivo study

16249 ORAL COMMUNICATION BASIC RESEARCH

Background

Local administration of antibiotics into gingival sulcus has been a highly efficient method to deliver the agents. However, constant flow of gingival crevicular fluid and saliva instantaneously clears the substances away from gingival sulcus. Therefore, various carriers have been studied to extend the retention of antibiotic agents and have shown improved treatment outcome. Among many, chitosan-alginate (CA) microspheres were reported to be effective in increasing the sustainability.

Aim/Hypothesis

The aim of this in vivo study was to compare the retention rate of injectable local minocycline agents with different carriers via visual inspection and broth microdilution method and their efficacy through radiographical and clinical evaluation.

Material and Methods

Four implants were placed on both sides of 6-male beagle dogs following 3 months after tooth extraction. After 4 weeks of healing period, each side of mandible was randomly assigned to peri-implant mucositis (PM) or peri-implantitis (PI) group. After inducing PM and PI, the antibiotic agents were locally administered after two weeks of healing period; once every 28 days for two times using a plastic tip syringe. Each implant was randomly assigned to receive one of the four treatment modalities- CA-based minocycline (CM), CA placebo (CA-substrate without minocycline, CP), Glycerin-based minocycline (GM) and no treatment (NC). The retention of local delivery agents was assessed by visual inspection of healing abutments and broth dilution test of the collected samples from gingival sulcus at 1,3,7,14,28 days after the delivery. Clinical parameters were evaluated by bleeding on probing(BOP) and probing depths(PD). Bone level changes were also evaluated with peri-apical radiographs.

Results

A statistically significant prolonged retention of the agent was presented in CM (12.8 ± 3.2 days) and CP (16.3 ± 3.4 days) compared to GM (0 days) (P = 0.00) at first drug administration and CM (17.2 ± 2.9 days) and CP (14.0 ± 2.6 days) compared to GM (0.3 ± 0.3 days) (P = 0.00) at second drug administration. A statistically significant retention of minocycline was also detected at broth dilution test in CM (8.2 ± 1.7 days) compared to GM (1.2 ± 0.8 days) (P = 0.01). A negligible average bone loss [0.29(GM) to 0.43(CP) mm] were observed in PM before and after the treatment. Average bone level change in PI was also minimal [−0.2(GM) to 0.1(CP) mm] with no statistical difference. Increased BOP % was observed in PM [0(GM) to 25%(CM)], however, decreased BOP % was observed in PI [−15(CM) to −50%(GM)]. Minimal PD changes were observed in PM [−0.4(CM) to 0.1(GM) mm]. A slight average bone gain was observed in the PI [0.8(GM) to 1.5(CP) mm]. All numbers showed no statistical difference.

Conclusion and clinical implications

Chitosan-alginate based minocycline gel presented prolonged retention of minocycline compared to glycerin-based minocycline gel. Minimal bone level changes from both PM and PI show that local administration of minocycline agents does not influence the osseointegration of peri-implant diseases. A greater improved outcome of BOP and PD in PI compared to PM indicate that local minocycline delivery is more effective in more progressed peri-implant disease.