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Intra-observer reliability regarding removal of asymptomatic third molars


Objective: To investigate reliability of practitioners' removal decisions and judgements of risk of pathology associated with asymptomatic third molars.

Subjects: 10 oral surgeons and 18 family dentists from South Wales with experience ranging from 5 to 28 years.

Method: Participants were presented with periapical radiographs of 36 asymptomatic, mandibular third molars and were informed of the age and sex of the patients and the degree of eruption of the third molars. Participants were asked to assess, using visual analogue scales, the likelihood of future pathology if the third molars were left in situ and to indicate if they should be removed or not. To assess intra-observer reliability, the 36 cases were duplicated and presented to the participants on a different occasion, a month later. The same questions were asked as on the first occasion.

Results: Significant correlations (Pearsons correlation coefficients) were found between initial and repeat assessments of all measures but there was little agreement about the need for removal (Kappa values: 0.54 for oral surgeons and 0.41 for the family dentists). For every item studied, changes in position on the visual analogue scale of two-thirds or more of the total length occurred from the first to the second assessment.

Conclusion: Treatment decisions about whether or not to remove asymptomatic third molars were not made on a rational basis. Since similar conclusions were recorded in a previous Swedish study, it is inferred that until further high quality evidence of disease prediction is published, decisions to remove third molars prophylactically cannot be made reliably


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Kostopoulou, O., Brickley, M., Shepherd, J. et al. Intra-observer reliability regarding removal of asymptomatic third molars. Br Dent J 184, 557–559 (1998).

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