Titanium versus zirconia complete arch implant-supported fixed prostheses: A comparison of plaque accumulation

Statement of problem. Complete arch implant-supported zirconia prostheses appear to have less plaque accumulation than titanium prostheses, but a comparison of the materials and the possible influence on the adjacent soft tissue is lacking.Purpose. The purpose of this clinical study was to compare the plaque accumulation and soft-tissue inflammation of complete arch implant-supported fixed maxillary prostheses fabricated with either a titanium framework or monolithic zirconia.Material and methods. Twenty participants with a complete arch implant-supported fixed maxillary prosthesis were enrolled in the study. The participants were divided into 2 groups according to the prosthesis material, titanium (Ti) or zirconia (Zir). The prosthesis had to have been in function for at least 6 months, and participants were examined during at least 3 maintenance appointments at 3-month intervals. Clinical information collected in each appointment included standardized photographs to record the Plaque Area Index (PAI) of the intaglio surface of the prosthesis; clinical parameters including modified Plaque Index (mPI), modified Bleeding Index (mBI), implant mobility (MOB), probing depths >= 5 mm (PD), suppuration (SUP), keratinized tissue band >= 2 mm (KT), and an intraoral photograph of the maxillary arch without the prosthesis to evaluate the redness of the soft tissues.Results. MOB was not present at any implant at any time point. SUP could not be analyzed because it was an infrequent finding. Both groups exhibited significant increases in mBI over time. No significant differences were observed for PD between the groups at any time point. Implants in the Ti group had significantly higher KT values than those in the Zir group; levels remained constant over time for both groups. Zirconia prostheses had slightly lower PAI levels than Ti prostheses. The PAI in the Zir group significantly decreased over time (P=.035); in the Ti group, they remained constant (P=.45). Higher PAI levels were correlated with increased levels of erythema; both groups had a significant decrease in erythema values over time (P=.04).Conclusions. Zirconia complete arch implant-supported fixed maxillary prostheses displayed a significant decrease in plaque accumulation in individuals who had received periodic maintenance and oral hygiene instructions. Ti prostheses had significantly higher plaque levels than zirconia prostheses at all time points, which was not reduced by maintenance and oral hygiene measures. The present study suggests that patients receiving zirconia prostheses respond well to plaque control measures, while plaque control for those with titanium prostheses may be more challenging.