A comparative evaluation between the reliability of gypsum casts and digital greyscale intra‐oral scans for the scoring of tooth wear using the Tooth Wear Evaluation System (TWES)

BACKGROUND: The Tooth Wear Evaluation System (TWES) is a type of tooth wear index. To date, there is the lack of data comparing the reliability of the application of this index on gypsum cast records and digital greyscale intra‐oral scan records. OBJECTIVES: A comparative evaluation between the use of gypsum cast records and digital greyscale intra‐oral scan records with the reliability of tooth wear scoring using the TWES amongst a group of patients with tooth wear. METHODS: Records for 10 patients with moderate to severe tooth wear (TWES ≥ 2) were randomly selected from a larger clinical trial. TWES grading of the occlusal/incisal, buccal and palatal/lingual surfaces was performed to determine the levels of intra‐ and interobserver agreement. Intra‐observer reproducibility was based on the findings of one examiner only. For the interobserver reproducibility, the findings of two examiners were considered. One set of models/ records were used per patient. Cohen's weighted kappa (κ(W)) was used to ascertain agreement between and within the observers. Comparison of agreement was performed using t tests (P < .05). RESULTS: For the scoring of the of the total occlusal/incisal surfaces, the overall levels of intra‐ and interobserver agreement were significantly higher using the gypsum cast records than with the digital greyscale intra‐oral scan records, (P < .001) and (P < .001), respectively. For the overall buccal surfaces, only a significant difference was found in the intra‐observer agreement using gypsum casts, (P = .013). For the palatal/lingual surfaces, a significant difference was only reported in the interobserver agreement using gypsum casts, (P = .043). At the occlusal/incisal surfaces, grading performed using gypsum casts, culminated in significantly higher TWES scores than with the use of the digital greyscale intra‐oral scans (P < .001). At the buccal and palatal/lingual surfaces, significantly higher wear scores were obtained using digital greyscale intra‐oral scan records (P < .009). CONCLUSIONS: The TWES can offer a reliable means for the scoring of wearing occlusal/incisal surfaces using gypsum casts. The reliability offered by digital greyscale intra‐oral scans for consecutive scoring was in general, inferior.