Periodontal disease is a highly prevalent chronic inflammatory condition and remains a leading cause of tooth loss worldwide. In addition to functional impairment, untreated periodontitis has significant psychosocial consequences, negatively affecting eating, speech, appearance, and overall quality of life. Research consistently shows that periodontitis is associated with poorer oral health-related quality of life (OHRQoL), with improvements observed following periodontal therapy.
However, while OHRQoL tools such as the Oral Health Impact Profile (OHIP) are valuable for capturing patient-reported outcomes, they are not preference-based measures and therefore cannot be directly used for health economic evaluations. In health economics, health state utility values are essential because they allow outcomes to be expressed on a standardized scale from 0 (death) to 1 (perfect health), enabling calculation of quality-adjusted life years (QALYs). This permits direct comparison of dental interventions with other healthcare services in cost-utility analyses. Despite this importance, HSUVs remain underutilized in dentistry, with only limited attempts made to derive utility values for periodontal health states. Most periodontal cost-effectiveness studies continue to rely on intermediate clinical outcomes, such as probing depth reduction, rather than patient-centered utility measures, which limits their policy relevance. Health state utility values can be elicited using either direct methods such as the Standard Gamble (SG) and Time Trade-Off (TTO), or indirect instruments like the EQ-5D. Direct methods capture individual preferences by asking patients to make trade-offs between life expectancy, health states, or risk of death, whereas indirect instruments classify health across domains and apply population preference weights.
While indirect tools are widely used in medicine, they are often criticized for lacking sensitivity to oral health conditions, which may underestimate the true burden of periodontitis. Adapting direct elicitation methods to periodontal health contexts is therefore necessary to generate valid and meaningful utility values. Beyond clinical outcomes, patients' valuation of periodontal treatment may be shaped by psychological and behavioural constructs. The Health Belief Model (HBM) suggests that perceptions of susceptibility, severity, benefits, and barriers strongly influence oral health behaviours. Evidence from periodontology confirms that compliance with oral hygiene instructions and adoption of preventive behaviours are associated with patients' health beliefs. More recently, psychosocial traits such as self-efficacy and self-esteem have been identified as predictors of the degree of OHRQoL improvement following periodontal therapy. This highlights the possibility that oral health beliefs also play a role in how patients assign utility values to treatment outcomes Current evidence shows that OHRQoL outcomes still dominate periodontal research, while Health state utility values are rarely measured and seldom applied in economic evaluations. The few studies that have attempted to quantify utility values for periodontal treatment have been methodologically limited, and little is known about the role of oral health beliefs in shaping how patients assign value to treatment. Addressing these gaps is essential for generating robust evidence that reflects both economic efficiency and patient-centered perspectives. Therefore, this study aims to measure dental health state utility values for periodontal treatment and to examine their association with clinical periodontal status and oral health beliefs. By integrating dental health state utility values measurement with psychosocial constructs, the study will provide data essential for cost-utility modelling and patient-centered care.
