Methods: Patients with symptom-free impacted wisdom teeth were recruited from 6 general dental practices in Tayside, Scotland and followed for a year to assess the development of problems related to impaction. Patients completed the OHIP-14 at baseline and one-year follow-up. The OHIP-14 was analysed using three scoring methods: a summary score, a weighted and standardised score, and the total number of problems reported. Instrument reliability was measured by assessing internal consistency and test-retest reliability. Construct validity was assessed using a number of variables. Stepwise linear regression was then used to model the relationship between OHIP-14 and all significantly correlated variables. Responsiveness was measured using the standardised response mean (SRM).
Results: 239 patients completed the questionnaire. Reliability- Crombach’s Alpha coefficients ranged from 0.49 to 0.74 at baseline and 0.30 to 0.75 at one year follow-up. Alpha coefficients for all 14 items were 0.88 and 0.87 for baseline and follow-up respectively. Test-retest coefficients for asymptomatic patients ranged from 0.72 to 0.78. Validity- OHIP-14 scores were significantly correlated with number of teeth, education, main activity, the use of mouthwash, frequency of seeing a dentist, the reason for the last dental appointment, smoking and alcohol intake for baseline and number of teeth, pain and symptoms for the follow-up. Adjusted R² ranged from 0.152 to 0.174 for baseline and from 0.151 to 0.185 at follow-up. Responsiveness- The SRMs ranged from 0.37 to 0.56 for symptomatic and from 0.07 to 0.13 for asymptomatic patients.
Conclusions: The OHIP-14 is a valid and reliable measure of OHRQoL in general dental practice and is responsive to clinical change in this population. Of the three scoring methods used, the summary score method demonstrated superior validity and responsiveness.
Supported by the Wellcome Trust and TayRen.