Zi crowns and 3-unit PFDPs fabricated using the specific CAD-CAM system show good clinical outcomes

Zi crowns and 3-unit PFDPs fabricated using the specific
CAD-CAM system show good clinical outcomes according to a recent study published
in the Journal of Dentistry.

The aim of this retrospective clinical study was to evaluate
the survival and the occurrence of technical and biological complications in
bi-layered zirconia-based (Zi) single crown and 3-unit fixed dental prostheses
(FDPs). Also, the study aimed to analyze the effects of tooth vitality (vital
versus non-vital), abutment location (anterior versus posterior), and luting
cement (self-adhesive resin versus resin-reinforced glass ionomer) on clinical
outcomes.

A total of 147 prostheses (in 94 patients) placed by
undergraduate dental students in a university dental center during the period
2015–2021 were examined clinically using modified United States Public Health
Service (USPHS) and California Dental Association (CDA) criteria. The mean
duration of follow-up was 37 months (range, 6 – 63 months) for the single
crowns (n = 77) and 25 months (range, 6 – 68 months) for the 3-unit FDPs (n =
70). Data were descriptively analyzed to determine the types and rates of
complications based on USPHS and CDA criteria. The Kaplan-Meier survival
estimation method was used to determine the cumulative survival and success
rates of the prostheses (α=0.05). Differences in clinical outcomes (survival or
failure) according to tooth vitality, luting cement, and location were statistically
analyzed using cross-tabulations and Х2 test (α=0.05).

Results

  • The Kaplan-Meier cumulative survival rate was
    estimated as 96% for the Zi 3-unit FDPs after 5.5 years, and 90% for the Zi
    single crowns after 4.8 years.
  • The 5-year estimated success rate was 68% for
    both 3-unit FDPs and single crowns. Seven (9.1%) 77Zi single crowns and 70 2
    (2.9%) Zi 3-unit FDPs were recorded as failures with occlusal roughness being
    the most commonly-observed complication (crowns: 4 [5.6%]; 3-unit FDPs: 8 [11.4%]).
  • In terms of clinical outcomes, statistically
    significant differences were found between all included vital and non-vital
    teeth (p = .006), and cement types (p = .028).
  • Taking single crowns alone, significant
    differences in clinical outcomes according to tooth vitality were noted (p =
    .036), but not for PFDPs.
  • The location of the prostheses did not produce
    any significant differences in the clinical outcomes, for both prostheses types
    independently or combined (p > .05).

The estimated cumulative survival rates in this study for
single crowns and 3-unit Zi FDPs concurred with the ranges reported in
systematic reviews. Zi-based prostheses on vital teeth produced better clinical
outcomes than those placed on non-vital teeth, and type of luting cement
influenced the final clinical outcome.

Reference:

Reem Alfadhli, Yara Alshammari, Mirza Rustum Baig, Ridwaan
Omar. Clinical outcomes of single crown and 3-unit bi-layered zirconia-based
fixed dental prostheses: An upto 6- year retrospective clinical study: Clinical
outcomes of zirconia FDPs, Journal of Dentistry, Volume 127, 2022, 104321, ISSN
0300-5712. https://doi.org/10.1016/j.jdent.2022.104321.

Keywords:

Reem Alfadhli, Yara Alshammari, Mirza Rustum Baig, Ridwaan
Omar, Clinical, outcomes, single, crown, 3-unit, bi-layered, zirconia-based,
fixed, dental, prostheses, upto 6- year, retrospective, clinical study, Clinical,
outcomes, zirconia, FDPs, Journal of Dentistry

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