Sven Reich

Survival probability of zirconia-based fixed dental prostheses up to 5 yr: a systematic review of the literature.

The purpose of this systematic review was to calculate the 5-yr survival rates of all-ceramic zirconia-based fixed dental prostheses (FDPs) and to analyze technical and biological complications. An electronic literature search of MEDLINE (PubMed) was conducted independently by three reviewers to identify clinical studies from 1999 to 2009 and was completed by a manual search. Keywords and inclusion and exclusion criteria were well-defined. The search revealed 399 titles and led to the final analysis of 18 full-text articles. Nine studies met the inclusion criteria. Extracted data were statistically calculated into 5-yr survival rates and 5-yr complication-free rates by using Poisson regression analysis. In total, 310, 3- to 4-unit FDPs and 20 FDPs with more than 4 units were included. The estimated 5-yr survival rate for all FDPs was 94.29% (95% CI: 58.98-99.32); 19 FDPs were lost as a result of catastrophic failures. The 5-yr complication-free rate regarding technical complications was 76.41% (95% CI: 42.42-91.60) with chipping being the most frequent complication. Regarding biological complications, the 5-yr complication-free rate was 91.72% (95% CI: 59.19-98.53). The survival rates of zirconia-based short-unit FDPs are promising. However, an important improvement of the veneering systems is required, and for FDPs with more units in function, further randomized, controlled clinical trials are necessary.

The clinical accuracy of single crowns exclusively fabricated by digital workflow—the comparison of two systems

ObjectivesThe purpose of the study was to compare the accuracy of crowns exclusively fabricated by the digital workflow of two systems. The null hypothesis stated was: Both systems do not differ with respect to marginal and internal accuracy.Materials and methodsIn 14 patients, 13 molars and 1 premolar were prepared. Each preparation was scanned intraorally with two different digital impression systems, Lava COS and Cerec AC. On the basis of these data, Lava DVS crowns [DVS] and Vita Rapid Layering Technique crowns [RLT] were fabricated, respectively. Both systems contained of a zirconia framework and a digitally fabricated silicate ceramic veneering. The marginal and internal fit of the crowns was documented by a replica technique. The replicas were examined under microscope with a magnification of ×200. The Wilcoxon signed rank test was applied in order to test if the values of the two systems showed significant differences at p ≤ 0.05.ResultsThe results were as follows in micrometers (±standard deviation): at the marginal gap, 51 (±38) for [DVS] and 83 (±51) for [RLT]; mid-axial, 130 (±56) for [DVS] and 128 (±66) for [RLT]; axio-occlusal, 178 (±55) for [DVS] and 230 (±71) for [RLT]; and centro-occlusal, 181 (±41) for [DVS] and 297 (±76) for [RLT]. According to the Wilcoxon signed rank test, the results differed significantly at the marginal, axio-occlusal, and centro-occlusal gaps.ConclusionsThe null hypothesis had to be rejected.Clinical relevanceThe exclusively digital workflow on the basis of intraoral digital impressions delivered clinically satisfying results for single crowns with both systems.

Virtual Dental Patient: How Long Until It’s Here?

Purpose of ReviewRecent developments in digital technology to be generated by superimposing different 3D imaging datasets. The aim of this literature review was to provide an update on the current status of knowledge, to report on the progress in virtual patient science, and to identify further research needed to facilitate the translation to clinical practice.Recent FindingsCase reports were identified describing different dental patient simulation techniques. Publications focused mainly on methodological feasibility of combining skeletal, facial, and dental imaging to produce virtual simulations. Clinical randomized controlled trials were scarce.SummarySuperimposition of 3D medical data files is a feasible technique to create a virtual patient under static conditions. 3D image fusion is of interest and importance in all fields of dental medicine including diagnostics, treatment, science, and education. Future research should focus on simplifying the technology, to enable virtual patient simulation to be generated in a single-step approach.