Objectives: Dental implant treatment (DIT) improves peoples’ oral health-related quality of life (OHQoL). Assessment of longitudinal changes in OHRQoL may be undermined by response shift (RS). RS is the process by which quality of life changes, independent of health status as a result recalibration, reprioritization or reconceptualization. Thus, this study aimed to describe RS in the OHRQoL and perceived oral health of individuals receiving DIT and to compare the then-test, a self-anchored scale and the classification and regression trees (CRT) approaches for assessing RS.
Methods: OHRQoL was assessed in 100 patients receiving DIT using the OHIP-Edent (n = 100) and a self-anchored scale (n = 45) before placement of the final restoration and 3 to 6 months after treatment was completed. The OHIP-Edent was also used as a retrospective assessment at follow-up. CRT examined changes in the OHIP-Edent total score as a dependent variable with global changes in oral health and each OHIP-Edent subscale score as independent variables.
Results: OHRQoL and perceived oral health improved after treatment. The OHIP-Edent score decreased from 36.4 at baseline to 12.7 after treatment. On average, participants recalibrated their internal standard downwards (− 4.0 OHIP-Edent points). CRT detected downwards recalibration in 5% of participants and upwards in 15%. Reprioritization was observed in the social disability and psychological discomfort aspects of OHRQoL.
Conclusions: RS affects longitudinal assessments of OHRQoL in DIT, reducing the apparent magnitude of change. The then-test and CRT are valid and complementary methods to assess RS.
- Dental implants
- Oral health
- Response shift