Validation, measurement properties, and minimal clinically important difference of short-version oral health impact profile (OHIP-5) by type of prosthodontic treatment: a prospective cohort study.

OBJECTIVES

To evaluate measurement properties of the 5-item Oral Health Impact Profile (OHIP-5) in Thai version, specifically its validity and responsiveness, as well as to compared with the Oral Impacts on Daily Performances (OIDP) and 14-item OHIP (OHIP-14) among patients undergoing conventional prosthodontic treatments. Minimal clinically important difference (MID) values of the treatment were also determined.

METHODS

This prospective cohort study was conducted in 133 prosthodontic patients, receiving complete dentures (CCD), removable partial dentures (RPD), or fixed dental prostheses (FDP). Tooth loss conditions were compared based on the number of functional teeth and posterior occluding pairs. Oral health-related quality of life (OHRQoL) outcomes were assessed at baseline (before prosthodontic treatment), and at 3 months and 6 months after treatment, using the OIDP, OHIP-14, and OHIP-5 questionnaires. Differences in OHRQoL scores across tooth loss conditions, and before and after treatment were compared using non-parametric analyses. Convergent validity was examined by Kendall's Tau-b correlation between OHIP-5, OHIP-14, and OIDP.

RESULTS

Significant differences in OIDP and OHIP scores across tooth loss conditions supported the known-groups validity. The OHIP-5 Thai showed strong correlations with OHIP-14 and OIDP, confirming convergent validity. OHRQoL scores decreased over 6 months after the treatment in all questionnaires, indicating good responsiveness. MID values of the treatment were higher for the CCD and RPD patients, while MID scores for the FDP patients were near zero when assessed using OHIP questionnaires.

CONCLUSION

The Thai version of OHIP-5 is a valid and responsive instrument for evaluating outcomes of CCD and RPD treatments. However, due to near-zero MID values, it may be less suitable for assessing treatment changes following FDP treatment.

CLINICAL RELEVANCE

The OHIP-5 Thai is a practical and efficient instrument for assessing OHRQoL problems and for evaluating patient outcomes following conventional prosthodontic treatments. Its performance is correlated with longer OHRQoL instruments, making it suitable for both clinical practice and research settings, supporting patient-centered, evidence-based prosthodontic care. The established MID scores offer valuable benchmarks for interpreting clinically meaningful changes. However, its use may be limited in patients with sufficient functional teeth receiving FDP, as it may be unable to capture meaningful changes.