Methodological studies of orofacial aesthetics, orofacial function and oral health-related quality of life

University dissertation from Malmö University, Departments of Stomatognathic Physiology and Prosthetic Dentistry, Centre of Oral Rehabilitation, Östergötland County Council, Linköping, Sweden

Abstract: Among researchers and in the general population, awareness of the impact of health and health care on the quality of human life is increasing. An important medical and dental research area that addresses this issue is health measurement scales and psychometrics. Such instruments have numerous uses, such as to screen psychosocial aspects in individual patient care, assess perceived health or disease in population surveys, measure outcome in clinical trials, and gather data for cost-utility analyses. Assessing and improving oral health-related quality of life (OHRQoL), orofacial function, and orofacial aesthetics are three major goals in dental care. The overall aim of this thesis was to describe how three assessment tools were developed—using current scientific methodology—to measure these concepts in the Swedish culture. This thesis comprises five studies. In article I, recommended guidelines were used to translate the Oral Health Impact Profile (OHIP), an OHRQoL instrument, into Swedish. A group of 145 consecutive patients comprising five diagnostic groups participated in reliability and validity evaluations of OHIP-S, the Swedish OHIP version. Data supported excellent reliability and acceptable validity. In article II, the Jaw Functional Limitation Scale (JFLS) was developed, and reliability and validity were assessed in 132 consecutive patients from five diagnostic groups. An expert panel identified 52 functional limitation items. Rasch methodology reduced the number of items to 20 and assessed model fit. Three constructs were identified—mastication, vertical jaw mobility, and emotional and verbal expression—and good reliability and validity were found. The JFLS-20 is an organ-specific instrument for assessing functional status of the masticatory system while the shorter JFLS-8 assesses global functional limitation. Article III describes development of the Orofacial Aesthetic Scale (OAS), in particular its conceptual framework, measurement model, and method of questionnaire item generation. Interview and questionnaire data from 17 prosthodontic patients created an initial 28-item pool. After focus group reduction and pilot testing, a final 8-item instrument was generated. Exploratory factor analysis investigated OAS dimensionality, and item analysis was performed in 119 subjects. Forward and backward translations and reconciliation produced an English version of the instrument. Exploratory factor analysis supported OAS unidimensionality. In article IV, psychometric properties of the OAS were evaluated in 119 patients from four groups: aesthetically compromised, functional disability, and two age- and gender-matched control groups. Various methods of testing reliability and validity supported good score reliability and validity. In article V, the OAS was part of a mail survey to a national sample of 3000 persons and normative values were derived. Survey respondents totaled 1406, and missing data were analyzed. There was a significant difference in OAS for age, gender, self-reported oral health, and self-reported general health status groups. Subjects who reported extreme satisfaction (item score of 10) varied between 17% for “color of the teeth” and 30% for “appearance of face” and “profile”. The OHIP, JFLS, and OAS are considered well suited for use in research and as clinical outcome measures in patients with functional and aesthetic concerns, such as prosthodontic patients.

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