Self-reported questionnaire and salivary biomarkers for periodontitis screening in Malaysian adults / Ho Jan Yang

Ho , Jan Yang (2025) Self-reported questionnaire and salivary biomarkers for periodontitis screening in Malaysian adults / Ho Jan Yang. PhD thesis, Universiti Malaya.

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Abstract

Salivary biomarkers and self-reported oral health questionnaire (SROH) could act as two convenient and non-invasive approaches for periodontitis screening. Their advantages are manifold, given that periodontal examination protocols such as full-mouth periodontal examination, Basic Periodontal Examination and Community Periodontal Index of Treatment Need require more manpower, equipment, time and cost. This study aimed to validate the SROH as a screening tool for periodontitis among the Malaysian population and to compare the salivary levels of interleukin-1β (IL-1β), interleukin-6 (IL-6), tumour necrosis factor-alpha (TNF-α), matrix metalloproteinase-8 (MMP-8), matrix metalloproteinase-9 (MMP-9) and metallothionein (MT) between patients with periodontal health, gingivitis or periodontitis. First, content of the SROH was validated by experts followed by face validation by a pilot sample of subjects who were uninvolved in the main study. Next, a convenience sample of 77 systemically healthy adults was recruited consecutively and divided into groups of periodontal health, gingivitis and periodontitis. The participants were asked to answer the self-administered SROH, followed by collection of unstimulated saliva samples. Five millilitres of saliva were collected within 30 minutes. After centrifugation, the resultant supernatants were aliquoted and stored at -80°C until analysis. The SROH responses were used to determine the construct validity, concurrent validity, internal consistency and test-retest reliability of the questionnaire. Concurrently, quantification of salivary biomarker levels was determined using enzyme-linked immunosorbent assay. Differences in salivary biomarker levels between groups were compared with Kruskal Wallis H test with posthoc Dunn test. Spearman correlation coefficient was used to study the linear relationship between salivary biomarker levels and clinical periodontal parameters. Multivariate binary logistic regression for the presence of periodontitis was performed using demographic variables, salivary biomarker levels and responses to SROH as predictors. The diagnostic accuracy, sensitivity and specificity of the predictive models were determined by plotting a receiver operating characteristics curve. After some modifications, the final six-item SROH was considered to be valid and reliable, with scale-level content validity index of one, scale-level face validity index of 0.837, internal consistency/Cronbach alpha of 0.813, test-retest reliability of 0.975 and all items having factor loading score >0.5. Significant intergroup differences were observed in salivary levels of IL-1β, IL-6, MMP-8 and MMP-9. The levels of IL-1β and IL-6 were significantly higher in periodontal disease states relative to periodontal health. Meanwhile, the highest expression of MMP-8 and MMP-9 was found in the periodontitis group. Multivariate logistic regression analysis for the discrimination of periodontitis from nonperiodontitis groups demonstrated good predictive ability of models combining social demographics, SROH responses and salivary biomarker levels, with diagnostic performance exceeding 90%. In conclusion, the development of prediction model that integrated patient characteristics, SROH responses and levels of selected salivary biomarkers offered a sufficiently accurate and non-invasive means of periodontitis screening that should be validated in future studies.

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