Inter–examiner Reliability of Salivary Diagnostic Tests in a Practice–based Research Network

Abstract

Purpose: Patient salivary characteristics are being measured as part of the Northwest PRECEDENT (Practice-based REsearch Collaborative in Evidence-based DENTistry) study on caries risk assessment. Prior to the implementation of these salivary diagnostic tests in a practice-based cohort study, inter-examiner reliability was assessed for resting salivary pH, stimulated salivary flow rate, pH and buffering capacity.

Methods: An initial evaluation of inter-examiner reliability of the 4 salivary tests was conducted among 6 dental auxiliary examiners using a convenience sample of 40 dental students. An incomplete block design was used to assign samples to examiners (3 examiners per sample and 20 samples per examiner). Inter-examiner reliability testing was conducted on a patient population representative of the practice-based network in 4 member practices. Two dental assistants per practice independently conducted the salivary tests on samples provided by a random selection of 20 to 25 patients. A separate analysis was performed for each study. For each test, an inter-examiner reliability index was computed.

Results: Results from two studies are reported. In the first, stimulated salivary flow rate demonstrated excellent inter-examiner reliability, and resting salivary pH showed high inter-examiner reliability, while buffering capacity and stimulated salivary pH had moderate and very low inter-examiner reliability, respectively. In the second, inter-examiner reliability was excellent for the stimulated salivary flow rate and the resting salivary pH. The inter-examiner reliability for the stimulated salivary pH was also high and the stimulated salivary buffering capacity test had moderate reliability.

Conclusion: The small variance in stimulated salivary pH and buffering capacity in dental students may have artificially made the reliability appear low in the first attempt at inter-examiner reliability testing. In the second study, all 4 tests had an acceptable performance.

This study supports the NDHRA priority area, Health Promotion/Disease Prevention: Validate and test assessment instruments/strategies/mechanisms that increase health promotion and disease prevention among diverse population