Objective: The aim was to answer the clinical research question: is incisal/occlusal tooth wear assessment on dental casts performed by five professionals with expertise in different fields of dentistry reliable? Method and Materials: Five examiners with different fields of expertise in the dental profession assessed tooth wear on dental casts of 45 subjects, based on a six-degree rating of incisal/occlusal wear. After a calibration meeting, the examiners evaluated the casts individually and various issues concerning interexaminer agreement and reliability were assessed. Results: A total of 872 teeth were evaluated. The five examiners agreed only for the rating of 6.6% of the teeth. The teeth with the highest percentage of agreement were the premolars. Pairwise comparison of the assessments of the examiners #1 (bruxism expert), #2 (orthodontist), #3 (temporomandibular disorders [TMD] and occlusion expert), #4 (dental nurse) showed fair to moderate agreement, with κ-values ranging from 0.306 to 0.577, whilst the examiner #5 (lab technician) achieved low interexaminer reliability values with all the other four examiners. Conclusion: The interexaminer reliability of tooth wear assessment on dental casts performed by five professionals with expertise in different fields of dentistry is highly variable. General practitioners should keep in mind that consensus decisions by the examiners and assessment by raters belonging to the same dental discipline are recommended strategies to increase the reliability of tooth wear evaluation in the clinical setting. Clinical significance: This investigation adds to the literature suggesting that, in a clinical setting, a single examiner's assessment of tooth wear on dental casts does not have optimal reliability and that it may be source of internal validity problems in the research setting. Keywords: dental cast, interexaminer reliability, tooth wear