Influence of Full Crown Margin on Periodontal Conditions.

Objectives: To evaluate the influence of PFM crown margin on periodontal conditions in beagle dogs.Methods: Four beagle dogs were utilized in this study.Three weeks after commencing oral hygiene procedures through supragingival scaling and subgingival scaling,forty-nine dog teeth were prepared for receiving porcelain fused metal(PFM) crowns.One week later,the PFM crowns were cemented,whose buccal margins were made of porcelain fused to metal(PFM)and lingual margins were metal.Clinical parameters were recorded on all test teeth immediately before tooth preparation and after 4 weeks of cementation of PFM crowns.During the studying period,professional oral hygiene was performed for the Beagles dogs one time a week.Results: The results of animal research were that the volumn of GCF,the frequency of PLI≥1 and SBI≥2,PD and the activity of AST in GCF increased significantly for the group of lingual gingiva(P0.01) in the time of four weeks after cementation of crowns.For the buccal gingiva margin,the activity of GCF-AST and the frequency of SBI≥2 increased significantly(P0.05),but PD,GCF and the frequency of PLI≥1 didn't change significantly.The difference of GCF,the activity of GCF-AST and the frequency of SBI≥2 between two groups are significant after 4 weeks of cementation of crowns(P0.05).Conclusion: When professional oral hygiene was performed once a week,both PFM and metal margins could contribute to periodontal inflammation.The metal induced more inflammation than PFM.This might be that plaque adhered more on metal induced more.