A Prospective Clinical Cohort Investigation on Zirconia Implants: 5-Year Results

Abstract

Mid-term data on zirconia oral implants is very rare. Therefore, the aim of this prospective clinical investigation was to evaluate the survival rate and the marginal bone loss of a one-piece zirconia implant after five years. Patient-reported outcomes were also recorded. Zirconia implants to support single crowns (SC) or a 3-unit fixed dental prosthesis (FDP) were placed and subsequently restored. After the insertion of the implants, at prosthetic delivery, and after five years, standardized radiographs were taken to evaluate marginal bone loss (MBL). For bone tissue evaluation, linear mixed models with random intercepts were fitted. Twenty-seven patients received one implant for an SC and 13 patients received two implants for a 3-unit FDP. Three patients each lost one implant for an SC before prosthetic delivery. Thirty-five patients were seen after five years, and no further implant was lost. The cumulative five-year implant survival rate was 94.3%. The MBL from implant installation up to five years was 0.81 mm. The MBL from implant installation to prosthetic delivery was statistically significant (p < 0.001). Patients perceived a significant improvement in function, esthetics, sense, speech, and self-esteem from pretreatment up to the five-year follow-up. The present findings substantiate the clinical applicability of this implant system.

Keywords: alveolar bone loss; clinical study; dental implants; patient satisfaction; survival rate; zirconium oxide.

Figure 1

(a). Mean marginal bone loss (± Standard Deviation) irrespective of reconstruction from implant insertion until the 5-year follow-up. (b) Mean marginal bone loss for single crowns (SC) and fixed dental prosthesis (FDP) from implant insertion to the 5-year follow-up. 1 = 1-year follow-up; 5 = 5-year follow-up.

Figure 2

Standardized radiographs for the assessment of marginal bone loss (MBL): (a) implant insertion; (b) prosthetic delivery; (c) one-year follow-up; (d) five-year follow-up.

Figure 3

Box plot diagrams of patient-reported outcome measures (visual analog scales, %; (a).: function (eating); (b).: esthetic/appearance; (c).: sense; (d).: speech; (e).: self-esteem) sorted by restoration type (fixed dental prostheses, single crowns) before treatment (p pre), at prosthetic delivery (delivery), and at the follow-up appointments (1-y follow-up; 5-y follow-up). The lower horizontal lines represent the minimal documented values and the highest ones the maximal values. The lowest end of the box represents quartile 1 and the highest quartile 3. The bold line within the box is the median. The dots represent outliers.