A prospective clinical study to evaluate the performance of zirconium dioxide dental implants in single-tooth edentulous area: 3-year follow-up

Abstract

Background: Traditionally, dental implants have been made from titanium or titanium alloys. Alternatively, zirconia-based ceramic implants have been developed with similar characteristics of functional strength and osseointegration. Ceramic implants offer advantages in certain settings, e.g. in patients who object to metal dental implants. The aim of this study was to investigate the mid-term (36 months) clinical performance of a ceramic monotype implant in single-tooth edentulous area.

Methods: This was a prospective, open-label, single-arm study in patients requiring implant rehabilitation in single-tooth edentulous area. Ceramic implants (PURE Ceramic Implant, Institut Straumann AG, Basel, Switzerland) with a diameter of 4.1 mm were placed following standard procedure and loaded with provisional and final prostheses after 3 and 6 months, respectively. Implant survival rate and implant success rate were evaluated and crestal bone levels were measured by analysing standardized radiographs during implant surgery and at 6, 12, 24 and 36 months.

Results: Forty-four patients received a study implant, of whom one patient withdrew consent after 3 months. With one implant lost during the first 6 months after surgery, the implant survival rate was 97.7% at 6 months. No further implants were lost over the following 30 months, and 3 patients were lost to follow-up during this time frame. This led to a survival rate of 97.5% at 36 months. Six months after implant surgery 93.0% of the implants were considered "successful", increasing to 97.6% at 12 months and remaining at this level at 24 months (95.1%) and 36 months (97.5%). Bone loss was most pronounced in the first half-year after implant surgery (0.88 ± 0.86 mm). By contrast, between 12 and 36 months the mean bone level remained stable (minimal gain of 0.06 [± 0.60] mm). Hence, the overall bone loss from implant surgery to 36 months was 0.97 (± 0.88) mm.

Conclusions: In the follow-up period ceramic implants can achieve favourable clinical outcomes on a par with titanium implants. For instance, these implants can be recommended for patients who object to metal dental implants. However, longer term studies with different edentulous morphology need to confirm the present data.

Trial registration: Registered on www.clinicaltrials.gov : NCT02163395 .

Keywords: Ceramic implant; Dental implant; ZLA; Zirconia; Zirconium dioxide; ZrO2.

Conflict of interest statement

Ethics approval and consent to participate

The study was conducted in accordance with the Declaration of Helsinki (Seoul revision 2008), ISO 14155, all local legal and regulatory requirements, and the study protocol, and it was approved by the independent ethics committees of the coordinating investigator and all study sites, namely Freiburg Ethics Commission International (ref: 011/1616), Landesärztekammer Baden-Württemberg (ref: F-2O11–060-z) and the Ethics Committee of the Hannover Medical School (ref: 6015). All participating patients gave their written informed consent.

Consent for publication

Not applicable.

Competing interests

All authors except DW are involved in training and education activities for Institut Straumann AG, Basel, Switzerland. The authors declare that they have no further competing interests. Institut Straumann AG manufactures the implants. Therefore, Institut Straumann AG gains financially, if the PURE Ceramic Implants would be more widely used.

Publisher’s Note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Figures

Fig. 1

Illustration of the bone level measurements. (1) Implant shoulder to first implant-to-bone contact. (2) Distance between the threads of the implant

Fig. 2

Distribution of implants placed in the study. Number of implants placed at each tooth position. N = 44. N: Total number of implants placed

Fig. 3

Survival and success rate analysis. Scaling of the Y-axis 70% to 100%. ITT population (n = 44). n (0 m) = 44; n (6 m) = 43; n (12 m) = 42; n (24 m) = 41; n (36 m) = 40. Patients lost to follow-up during the 36-month follow-up period were excluded. CI: Confidence interval; ITT: Intention to treat; m: Months; n: Number

Fig. 4

Categorized bone level changes. ITT population (n = 44). n (0–6 m) = 39; n (0–12 m) = 39; n (0–24 m) = 38; n (0–36 m) = 37. Missing values were excluded from the analysis. ITT: Intention to treat; m: Months; n: Number

Fig. 5

Bone levels (mean ± SD) from implant surgery to 36-month follow up visit. ITT population (n = 44). n (0–6 m) = 39; n (0–12 m) = 39; n (0–24 m) = 38; n (0–36 m) = 37. Missing values were excluded from the analysis. ITT: Intention to treat; m: Months; n: Number; SD: Standard deviation

Fig. 6

Number of patients with plaque and sulcus bleeding. ITT population (n = 44). ITT: Intention to treat; n: Number