Tooth Wear Evaluation System (TWES) 2.0—Reliability of diagnosis with and without computer-assisted evaluation

Jakob C. Roehl*, Holger A. Jakstat, Kai Becker, Peter Wetselaar, M. Oliver Ahlers

*Corresponding author for this work

Research output: Contribution to JournalArticleAcademicpeer-review


Background: Tooth wear is a multifactorial process, leading to the loss of dental hard tissues. Therefore, it is important to detect the level of tooth wear at an early stage, so monitoring can be initiated. The Tooth Wear Evaluation System (TWES) enables such a multistage diagnosis of tooth wear. The further developed TWES 2.0 contains a complete taxonomy of tooth wear, but its reliability has not yet been validated. Objectives: The aim of the study was to examine in a randomised controlled trial (RCT) whether diagnoses made based on the TWES 2.0 are reproducible and whether this reproducibility is also achieved with computer-assisted diagnostics. Methods: 44 dental students received extensive training in TWES 2.0 assessment and taxonomy. The students each evaluated at least 10 (of the present 14) anonymised patient cases using gypsum models and high-resolution intra-oral photographs according to TWES 2.0. One half initially evaluated on paper; the other half used dedicated software (CMDfact / CMDbrux). After half of the patient cases (5), the evaluation methods were switched (AB/BA crossover design). The diagnoses were then evaluated for agreement with the predefined sample solution. Results: Evaluation of agreement with the sample solution according to Cohen's kappa indicated a value of 0.46 for manual (traditional) evaluation; and 0.44 for computer-assisted evaluation. Evaluation of agreement between examiners was 0.38 for manual and 0.48 for computer-assisted evaluation (Fleiss’ kappa). Conclusion: The results of this study proved that the taxonomy of the TWES 2.0 has acceptable reliability and can thus be used by dentists. Accordingly, the system can be learned quickly even by untrained practitioners. Comparable results are achieved with computer-assisted evaluation.

Original languageEnglish
Pages (from-to)81-91
Number of pages11
JournalJournal of Oral Rehabilitation
Issue number1
Early online date31 Oct 2021
Publication statusPublished - Jan 2022

Bibliographical note

Funding Information:
The authors would like to thank the participating dental students at the University of Hamburg at the University Medical Center Hamburg-Eppendorf for their voluntary participation in the study. In addition, we would like to thank the people responsible at the University Medical Center Hamburg-Eppendorf, who supported the conduct of the study by providing the necessary rooms, including Professor Dr. Udo Schumacher and Ms. Ursula Makowski, Institute of Anatomy; Professor Dr. Kai Rothkamm, Center for Oncology; and Dr. Peter Kurz, Bettina Gries, Simone Wegemann and Patrick Toczeck, Hamburg Dental Association, for providing the laptop computers.

Publisher Copyright:
© 2021 The Authors. Journal of Oral Rehabilitation published by John Wiley & Sons Ltd.


  • attrition
  • computer-assisted diagnosis
  • diagnosis
  • erosion
  • taxonomy
  • tooth wear
  • Tooth Wear Evaluation System 2.0


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