Previous exploratory analyses suggest that the Oral Health Impact Profile (OHIP) consists of four correlated dimensions and that individual differences in OHIP total scores reflect an underlying higher-order factor. The aim of this report is to corroborate these findings in the Dimensions of Oral Health-Related Quality of Life (DOQ) Project, an international study of general population subjects and prosthodontics patients. Using the project's Validation Sample (N=5,022), we conducted confirmatory factor analyses in a sample of 4,993 subjects with sufficiently complete data. In particular, we compared the psychometric performance of three models: a unidimensional model, a four-factor model, and a bifactor model that included one general factor and four group factors. Using model fit criteria and factor interpretability as guides, the four-factor model was deemed best in terms of strong item loadings, model fit (RMSEA=0.05, CFI=0.99), and interpretability. These results corroborate our previous findings that four highly correlated factors—which we have named Oral Function, Orofacial Pain, Orofacial Appearance, and Psychosocial Impact —can be reliably extracted from the OHIP item pool. However, the good fit of the unidimensional model and the high inter-factor correlations in the four-factor solution suggest that OHRQoL can also be sufficiently described with one score.

Although oral health-related quality of life (OHRQoL) as measured by the Oral Health Impact Profile (OHIP) is thought to be multidimensional, the nature of these dimensions is not known. The aim of this report was to explore the dimensionality of the OHIP using the Dimensions of OHRQoL (DOQ) Project, an international study of general population subjects and prosthodontics patients. Using the project's Learning Sample (N=5,173), we conducted an exploratory factor analysis on the 46 OHIP items not specifically referring to dentures for 5,146 subjects with sufficiently complete data. The first eigenvalue (27.0) of the polychoric correlation matrix was more than ten times larger than the second eigenvalue (2.6), suggesting the presence of a dominant, higher-order general factor. Follow-up analyses with Horn's parallel analysis revealed a viable second-order, four-factor solution. An oblique rotation of this solution revealed four highly correlated factors that we named Oral Function, Orofacial Pain, Orofacial Appearance, and Psychosocial Impact. These four dimensions and the strong general factor are two viable hypotheses for the factor structure of the OHIP.

Level of education, self-perception of affective and economic status, and quality of life are all related to patient satisfaction. However, the quality of dentures shows the strongest correlation with patient satisfaction. Not only the quality of the denture-bearing area but the denture-wearing experience itself seems to be more important in determining patient satisfaction with mandibular CDs.

The self-reported stress in the dental environment is still high and the stressors seem to be comparable amongst the participating countries. Effective management programmes are needed to minimise dental environment stress.

Background How dental patients are affected by oral conditions can be described with the concept of oral health-related quality of life (OHRQoL). This concept intends to make the patient experience measurable. OHRQoL is multidimensional and Oral Function, Orofacial Pain, Orofacial Appearance, and Psychosocial Impact were suggested as its four dimensions and consequently four scores are needed for comprehensive OHRQoL assessment. When only the presence of dimensional impact is measured, a pattern of affected OHRQoL dimensions would describe in a simple way how oral conditions’ influence the individual. Objective By determining which patterns of impact on OHRQoL dimensions (Oral Function-Orofacial Pain-Orofacial Appearance-Psychosocial Impact) exist in prosthodontic patients and general population subjects, we aimed to identify in which combinations oral conditions’ functional, painful, aesthetical, and psychosocial impact occurs. Methods Data came from the Dimensions of OHRQoL Project with OHIP-49 data from 6,349 general population subjects and 2,999 prosthodontic patients in the Learning Sample (N=5,173) and the Validation Sample (N=5,022). We hypothesized that all 16 patterns of OHRQoL dimensions should occur in these individuals who suffered mainly from tooth loss, its causes and consequences. A dimension was considered impaired when at least one item in the dimension was affected frequently. Results The 16 possible patterns of impaired OHRQoL dimensions were found in patients and general population subjects in both Learning and Validation Samples. Conclusions In a four-dimensional OHRQoL model consisting of Oral Function, Orofacial Pain, Orofacial Appearance, and Psychosocial Impact, oral conditions’ impact can occur in any combination of the OHRQoL dimensions.

Purpose A desideratum of oral health-related quality of life (OHRQoL) instruments - such as the Oral Health Impact Profile (OHIP) - is that they accurately reflect the structure of the measured construct(s). With this goal in mind, the Dimensions of Oral Health-Related Quality of Life (DOQ) Project was proposed to investigate the number and nature of OHRQoL dimensions measured by OHIP. In this report, we describe our aggregate data set for the factor analyses in the project, which consists of responses to the 49-item OHIP from general population subjects and prosthodontics patients from 6 countries, including a large age range of adult subjects and both genders. Material and methods The DOQ Project's aggregate data set combines data from 35 individual studies conducted in Croatia, Germany, Hungary, Japan, Slovenia, and Sweden. Results The combined data set includes 10,778 OHIPs from 9,348 individuals (N=6,349 general population subjects, N=2,999 prosthodontic patients). To elucidate the OHIP latent structure, the aggregated data were split into a Learning Sample (N=5,173) for exploratory analyses and a Validation Sample (N=5,022) for confirmatory analyses. Additional data (N=583) were assigned to a third data set. Conclusion The Dimensions of Oral Health-Related Quality of Life Project contains a large amount of international data and is representative of populations where OHIP is intended to be used. It is well-suited to assess the dimensionality of the questionnaire.

Objectives To integrate items from two widely used oral health-related quality of life (OHRQoL) questionnaires, the General Oral Health Assessment Index (GOHAI) and the Oral Impacts on Daily Performances (OIDP), as well as culturally-specific items of the Oral Health Impact Profile (OHIP) into a four-dimensional OHRQoL model consisting of Oral Function, Orofacial Pain, Orofacial Appearance, and Psychosocial Impact. Methods Subjects came from an ancillary study of the Dimensions of Oral Health-Related Quality of Life Project (N = 267 patients, mean age ± SD: 54.0 ± 17.2 years, 58% women.) Patients filled in the original 49 items of OHIP and 22 additional OHRQoL items in a cross-sectional study. These additional items consisted of 7 culturally specific OHIP items and 15 GOHAI or OIDP items with unique content not covered in OHIP-49. Before data collection, three experts hypothesized to which of the four OHRQoL dimensions these items belong. Hypotheses were tested in correlation analyses between the 22 items and the four dimension scores that were derived from OHIP-49. Results Five of the 22 items did not provide sufficient information to which dimension they belong. In 16 of the remaining 17 items, the pattern of correlation coefficients fitted experts’ a priori hypotheses. Acceptance of 16 of the 17 hypotheses was interpreted as evidence that additional (not in OHIP-49 contained) OHRQoL items can be assigned to Oral Function, Orofacial Pain, Orofacial Appearance, and Psychosocial Impact. Conclusion Items of three OHRQoL instruments can be integrated into a dimensional OHRQoL model consisting of Oral Function, Orofacial Pain, Orofacial Appearance, and Psychosocial Impact. Clinical significance Oral Function, Orofacial Pain, Orofacial Appearance, and Psychosocial Impact can serve as a simple and clinically appealing set of oral health-related quality of life (OHRQoL) dimensions and therefore provide an opportunity for simpler, but psychometrically improved OHRQoL measurement in the future.

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