Anterior tissues are delincate,and a healthy facial crevice in the anterior region is shallow;therefore,the potential for trauma  to the gingival tissues is great.Subgingival crown restorations,as opposed to supra-gingival restorations,are directly responsible for adverse inflammatory periodontal reactions because of these adverse reactions:

    1,the roughness or porosities found at the surface of the restorative materials;2,the roughness of aggravated by defective marginal fit or overhanging margins;3,the depth of the subgingival margin and its inaccessibility to toothbrushing;4,increased pathogenicity of the subgingival dental plaque;5,defective crown contours;6,invasion of the biologic width.

    Because subgingival placement of full-coverage restorations is necessary for aesthetic purposes,anterior tooth preparations must adhere to strict guidelines for predictability and stability at the gingival margin.

    For more information about dental cosmetic,please call us at +852 69416900 or visit www.dentalhospital.com.cn