CLINICAL AND MICROBIOLOGICAL ASSESSMENT OF CHLORHEXIDINE IMPACT ON GINGIVAL TISSUE RESPONSE AND BIOFILM FORMATION RELATED TO MATERIAL COMPOSITION IN FIXED PROSTHODONTIC RESTORATIONS.

The success of FDP is dependent on the interplay between restorative materials, gingiva tissues, and oral biofilm. Chlorhexidine (CHX) has been accepted as the gold standard for chemical plaque control because of its effect on both plaque accumulation and gingival inflammation. Prosthetic materials' surfaces may be modified when in contact with CHX, which presents higher surface roughness, colour stability loss and more ion release. Thus, this study evaluated the clinical and microbiological effects of CHX on FDPs with metal-ceramic and monolithic zirconia restorations. Thirty participants were enrolled. Both plaque and gingival indices were recorded, and biofilm samples were collected at baseline and after 2 weeks of rinsing with 0.12%CHX mouthrinse. Surface characteristics and mechanical properties of the restoratives were assessed in vitro following CHX exposure using surface roughness measurements, color stability analysis, and standard mechanical testing. The study demonstrated that CHX lowered plaque and microorganism counts. Metal-ceramic restorations showed significant surface changes and reduction in strength, while zirconia retained stable surface roughness values and mechanical integrity. These results suggest that zirconia is more chemically stable in CHX than metal ceramic restorations.