To investigate intra- and inter-observer reliability in identifying occlusal markings on mandibular dentures.
Method:
Three experimental groups (n=10) of junior dental students, senior students and clinical teachers identified occlusal markings on digital images of 14 mandibular dentures. The markings were made using articulating paper intra-orally. Each observer drew markings he/she earmarked for occlusal correction on a paper drawing of a mandibular denture. One series of images showed 14 single mandibular dentures; a second showed the same mandibular dentures with opposing dentures. Each image series was observed twice, with a 2-week interval. Before each subsequent assessment, the sequence of the images was randomised. Consensus reached between 2 experienced observers served as control data. Intra-rater reliability was established by comparing the difference of the means of sequential observations for each rater by establishing z-values. Inter-rater reliability within each group was established by means of analysis of variance (p<0.05).
Result:
For the single denture-series, the control mean total of markings was 56. For staff, junior and senior groups it was 48.5, 58.7, 55.5 respectively for the first observation; it was 56.6, 47.4, 60.9 respectively for the second observation. For the opposing denture-series, the control mean total of markings was 53. For staff, junior and senior groups it was 50.2, 61.8 and 56.8 respectively for the first observation; and 54.3, 38.6, 59 respectively for the second observation. Considering all data, observers’ mean scores didn’t differ from control mean scores in only 17 instances (of the possible 60), with good intra-rater reliability. In all other 43 instances observers’ mean scores differed from the control mean scores and/or displayed poor intra-rater reliability. Considerable variations in inter-rater reliability were found within all observer groups.
Conclusion:
Regardless of experience, observers are generally unable to reliably identify markings for occlusal adjustment made by articulating paper on dentures.