The objective of the study was to develop a Japanese version of the Oral Health Impact Profile (OHIP). The original 49 items were translated using a forward-backward method following accepted cultural adaptation guidelines. A de novo development of Japanese items was conducted to establish content validity. The associations between the OHIP summary score and self-reported oral health (n = 220) and self-reported denture quality (n = 155) were investigated for construct validity. The association between the OHIP summary score and six oral conditions (n = 227) were also tested. The responsiveness of the instrument was established by comparing the score before and after using newly fabricated removable partial dentures (n = 30). The test-retest reliability (n = 37) and internal consistency (n = 251) were also calculated. After the de novo development, five new items were added to the OHIP. The priori hypothesized associations between the OHIP score and oral health conditions were confirmed (P < 0.001). The change in the OHIP scores from 63.6 to 40.6 (P < 0.001) supports the responsiveness of the instrument. Intra-class correlation coefficients of 0.81 and Cronbach's alpha of 0.98 indicate high test-retest reliability and internal consistency of the instrument's summary score. Sufficient discriminative and evaluative psychometric properties of the currently developed Japanese version of the OHIP in typical target populations make the instrument suitable for assessing the oral health-related quality of life in cross-sectional as well as longitudinal studies.

BackgroundOne of the most immediate and important functional consequences of many oral disorders is a reduction in chewing ability. The ability to chew is not only an important dimension of oral health, but is increasingly recognized as being associated with general health status. Whether perceived chewing ability and oral health-related quality of life (OHRQoL) are correlated to a similar degree in patient populations has been less investigated. The aim of this study was to examine whether perceived chewing ability was related to OHRQoL in partially dentate patients.MethodsConsecutive partially dentate patients (N = 489) without signs or symptoms of acute oral disease at Tokyo Medical and Dental University's Prosthodontic Clinic participated in the study (mean age 63.0 ± 11.5, 71.2% female). A 20-item chewing function questionnaire (score range 0 to 20) was used to assess perceived chewing ability, with higher scores indicating better chewing ability. The 14-item Oral Health Impact Profile-Japanese version (OHIP-J14, score range 0 to 56) was used to measure OHRQoL, with higher scores indicating poorer OHRQoL. A Pearson correlation coefficient was calculated to assess the correlation between the two questionnaire summary scores. A linear regression analysis was used to describe how perceived chewing ability scores were related to OHRQoL scores.ResultsThe mean chewing function score was 12.1 ± 4.8 units. The mean OHIP-J14 summary score was 13.0 ± 9.1 units. Perceived chewing ability and OHRQoL were significantly correlated (Pearson correlation coefficient: -0.46, 95% confidence interval [CI]: -0.52 to -0.38), indicating that higher chewing ability was correlated with lower OHIP-J14 summary scores (p < 0.001), which indicate better OHRQoL. A 1.0-unit increase in chewing function scores was related to a decrease of 0.87 OHIP-J14 units (95% CI: -1.0 to -0.72, p < 0.001). The correlation between perceived chewing ability and OHRQoL was not substantially influenced by age and number of teeth, but by gender, years of schooling, treatment demand and denture status.ConclusionPatients' perception of their chewing ability was substantially related to their OHRQoL.

The impact of oral disorders and interventions on individuals' perceived oral health and oral-health-related quality of life (OHRQoL) is being increasingly recognized as an important health component. This study examined the association between denture quality and OHRQoL in individuals wearing removable partial dentures (RPDs). The study participants were 245 consecutive patients (mean age: 63.3 +/- 8.7 yrs) at a university-based prosthodontic clinic who wore RPDs for more than one month. RPD quality and OHRQoL were determined by means of a 100-mm visual analog scale (VAS) and the 49-item Oral Health Impact Profile-Japanese version (OHIP-J49), respectively. Linear regression analysis between RPD quality and OHRQoL revealed that a 10-mm VAS increase in RPD quality rating was related to -2.8 OHIP-J49 units (95% confidence interval: -4.5 to -1.1, p = 0.001), which represents an improvement in OHRQoL. The results suggest that RPD quality influences individuals' OHRQoL to a clinically significant extent.