Influence of a dental ceramic and a calcium aluminate cement on dental biofilm formation and gingival inflammatory response

Abstract: Dental restorative materials interact with their surrounding oral environment. Interaction factors can be release of toxic components and/or effects on biofilm formation and gingiva. In the end of the nineties, a calcium aluminate cement (CAC) was manufactured as a “bioceramic” alternative to resin composite. Dental ceramics are considered to be chemically stable and not to favour dental biofilm formation. Since the influence of aged, resin-bonded ceramic coverages is not fully investigated and the effect of CAC restorations on the dental biofilm formation and gingival response is unknown, those issues were evaluated in this thesis.With or without oral hygiene, in clinical trials including cervical surfaces of CAC, and approximal surfaces of a leucite-reinforced bonded ceramic; biofilm growth, presence of caries-associated bacteria, clinical expressions of gingivitis, the amounts of gingival crevicular fluid (GCF) and its levels of IL-1α, IL-1β and IL-1 ra were investigated in comparison with resin composite and enamel. In addition, the unknown cytotoxic effect of specimens of CAC on fibroblasts was assessed in vitro.With current oral hygiene a similar biofilm formation and gingival response, as evaluated, were observed at sites of CAC, resin composite and enamel. After ceased oral hygiene, more biofilm was assembled on CAC and on resin composite than on enamel. Neither with, nor without oral hygiene, biofilm formation, presence of caries-associated bacteria, clinical gingivitis and the levels of IL-1α, IL-1β and IL-1 ra differed between sites of ceramic, resin composite and enamel. Higher volumes of GCF were collected at ceramic sites compared to enamel. Fresh specimens of CAC showed the lowest cytotoxic effects on fibroblasts compared with three resin composites, zinc phosphate and glass ionomer cements.In conclusion, the low cytotoxic effect of CAC and the limited increase in dental biofilm formation on that material compared with enamel suggest CAC to be a biocompatible dental material with respect to dental biofilm formation, presence of caries-associated microflora and gingival response. This finding, together with the observation that the influence of bonded ceramic on dental biofilm formation, caries-associated microflora and clinical gingivitis was not different from that of enamel, implicates for both CAC restorations and bonded ceramic that the need of oral hygiene and professional oral health care is not reduced.