David Locker’s research while affiliated with University of Toronto and other places

Construction and validation of the quality of life measure for dentine hypersensitivity (DHEQ). Abstract Aim: To develop and validate a condition specific measure of oral health-related quality of life for dentine hypersensitivity (Dentine Hypersensitivity Experience Questionnaire, DHEQ). Materials and Methods: Questionnaire construction used a multi-staged impact approach and an explicit theoretical model. Qualitative and quantitative development and validation included in-depth interviews, focus groups and cross-sectional questionnaire studies in a general population (n 5 160) and a clinical sample (n 5 108). Results: An optimized DHEQ questionnaire containing 48 items has been developed to describe the pain, a scale to capture subjective impacts of dentine hypersensitivity, a global oral health rating and a scale to record effects on life overall. The impact scale had high values for internal reliability (nearly all item-total correlations 40.4 and Cronbach's a 5 0.86). Intra-class correlation coefficient for test–retest reliability was 0.92. The impact scale was strongly correlated to global oral health ratings and effects on life overall. These results were similar when DHEQ was validated in a clinical sample. Conclusions: DHEQ shows good psychometric properties in both a general population and clinical sample. Its use can further our understanding of the subjective impacts of dentine sensitivity.

This study assessed the efficacy of oral care education among nursing home staff members to improve the oral health of residents. Nursing home support staff members (NHSSMs) in the study group received oral care education at baseline between a pretest and posttest. NHSSMs' oral care knowledge was measured using a 20-item knowledge test at baseline, posteducation, and at a 6-month follow-up. Residents' oral health was assessed at baseline and again at a 6-month follow-up using the Modified Plaque Index (PI) and Modified Gingival Index (GI). Among staff members who received the oral care education (n = 32), posttest knowledge statistically significantly increased from the pretest level (p < .05). Thirty-nine control residents of the nursing homes and 41 study residents participated. Among residents in the study group, PI decreased at 6 months compared to baseline (p < .05), but there was no statistically significant difference in their GI measurements between baseline and 6-month follow-up (p= .07).

Tsakos G, Allen PF, Steele JG, Locker D. Interpreting oral health-related quality of life data. Community Dent Oral Epidemiol 2012. © 2011 John Wiley & Sons A/S Abstract – The most common way of presenting data from studies using quality of life or patient-based outcome (PBO) measures is in terms of mean scores along with testing the statistical significance of differences in means. We argue that this is insufficient in and of itself and call for a more comprehensive and thoughtful approach to the reporting and interpretation of data. PBO scores (and their means for that matter) are intrinsically meaningless, and differences in means between groups mask important and potentially different patterns in response within groups. More importantly, they are difficult to interpret because of the absence of a meaningful benchmark. The minimally important difference (MID) provides that benchmark to assist interpretability. This commentary discusses different approaches (distribution-based and anchor-based) and specific methods for assessing the MID in both longitudinal and cross-sectional studies, and suggests minimum standards for reporting and interpreting PBO measures in an oral health context.

To explore the issue of affordability in dental care by assessing associations between income, dental insurance, and financial barriers to dental care in Canadian adults. Data were collection from a national sample of adults 18 years and over using a telephone interview survey based on random digit dialing. Questions were asked about household income and dental insurance coverage along with three questions concerning cost barriers to accessing dental care. These were: "In the past three years...has the cost of dental care been a financial burden to you?...have you delayed or avoided going to a dentist because of the cost?...have you been unable to have all of the treatment recommended by your dentist because of the cost?" The survey was completed by 2,027 people, over half of which (56.0%) were covered by private dental insurance and 4.9 percent by public dental programs. The remainder, 39.1 percent, paid for dental care out-of-pocket. Only 19.3 percent of the lowest income group had private coverage compared with 80.5 percent of the highest income group (P < 0.001). Half (48.2%) responded positively to at least one of the three questions concerning cost barriers, and 14.8 percent responded positively to all three. Low income subjects (P < 0.001) and those without dental insurance (P < 0.001) were most likely to report financial barriers to care. While private dental insurance reduced financial barriers to dental care, it did not entirely eliminate it, particularly for those with low incomes. Those reporting such barriers visited the dentist less frequently and had poorer oral health outcomes after controlling for the effects of income and insurance coverage. Canadian adults report financial barriers to dental care, especially those of low income. These barriers appear to have negative effects with respect to dental visiting and oral health outcomes. For policy, appropriateness will be key, as clarity needs to be established in terms of what constitutes actual need, and thus which dental services can then be considered a public health response to affordability.

Objectives: This study aimed to assess the oral health status and needs of an adult homeless population in Toronto, Canada's largest municipality of approximately 2.5 million people; to determine how this homeless population interacts with the dental care system; and to learn how this population perceives their own oral health. Methods: This cross-sectional descriptive study collected data from 191 homeless adults living in 18 shelters in Toronto. A questionnaire and clinical oral examination were conducted with participants that were randomly selected using a stratified cluster sample of shelter beds. Descriptive and exploratory analyses were carried out using socio-demographic, general health and oral health self-perception variables. Results: Adults using homeless shelters in Toronto had 23 teeth on average and a mean DMFT score of 14.4 (SD 8.1). More than 60% of participants classified their oral health as fair/poor. Only 32% of the participants had visited a dentist during the last year, and 75% believed that they had untreated dental conditions. Approximately 40% indicated that their last visit to the dentist was for emergency care; 32% reported that they had toothache in the past month; and only 7% sought care for the toothache. The main reason for not seeking dental care was lack of money or no dental coverage. The clinical oral examination showed that 40% of participants required urgent treatment, 88% needed restorative treatment, and over 70% required periodontal treatment. While 85% of participants reported that the appearance of their teeth was important, 70% was not satisfied with their appearance. Conclusion: This adult homeless population in Toronto had poor oral health, significant oral health treatment needs and clearly lack of access to dental care. It is anticipated that upgrading oral health care assistance to homeless populations will be essential to improve access and to meet serious oral health needs.

Although the associations between oral biologic variables such as malocclusion and oral-health-related quality of life (OHRQOL) have been explored, little research has been done to address the influence of psychological characteristics on perceived OHRQOL. The aim of this study was to assess OHRQOL outcomes in orthodontics while controlling for individual psychological characteristics. We postulated that children with better psychological well-being (PWB) would experience fewer negative OHRQOL impacts, regardless of their orthodontic treatment status. One hundred eighteen children (74 treatment and 44 on the waiting list), aged 11 to 14 years, seeking treatment at the orthodontic clinics at the University of Toronto, participated in this study. The child perception questionnaire (CPQ11-14) and the PWB subscale of the child health questionnaire were administered at baseline and follow-up. Occlusal changes were assessed by using the dental aesthetic index. A waiting-list comparison group was used to account for age-related effects. Although the treatment subjects had significantly better OHRQOL scores at follow-up, the results were significantly modified by each subject's PWB status (P <0.01). Furthermore, multivariate analysis showed that PWB contributed significantly to the variance in CPQ11-14 scores (26%). In contrast, the amount of variance explained by the treatment status alone was relatively small (9%). The results of this study support the postulated mediator role of PWB when evaluating OHRQOL outcomes in children undergoing orthodontic treatment. Children with better PWB are, in general, more likely to report better OHRQOL regardless of their orthodontic treatment status. On the other hand, children with low PWB, who did not receive orthodontic treatment, experienced worse OHRQOL compared with those who received treatment. This suggests that children with low PWB can benefit from orthodontic treatment. Nonetheless, further work, with larger samples and longer follow-ups, is needed to confirm this finding and to improve our understanding of how other psychological factors relate to patients' OHRQOL.

Most measures of 'oral health-related quality of life' assess the presence and frequency of functional and psychosocial impacts rather than explicitly documenting their impact on the quality of life. The aim of this study was to evaluate Prutkin and Feinstein's suggestion for addressing the issue of quality of life in health outcome research by the use of global ratings. Data were collected from a national sample of Canadian adults by means of a telephone interview survey based on random digit dialing. Participants completed the OHIP-14. Those reporting one or more impacts in the previous year were asked three questions concerning the extent to which these impacts bothered them, affected their life as a whole, and affected their quality of life. These items were scored on a scale ranging from 'Not at all' to 'A great deal'. All participants were asked to rate the quality of their life using a six-point scale ranging from 'Very poor' to 'Excellent'. Interviews were completed with 2027 participants, and 2019 were included in the analysis. Overall, 19.5% reported one or more impacts 'fairly often' or 'very often'. Of these, 48.3% reported being bothered by these impacts, 40.3% that their life overall was affected, and 36.0% that their quality of life was affected. These individuals represent 9.4%, 7.8%, and 6.9% of the sample as a whole. Among those reporting impacts, there was a significant association between OHIP-14 extent and severity scores and the three ratings. Those with impacts that bothered them, that affected their life overall or affected their quality of life, rated their overall quality of life less favorably than those with impacts that did not. Analysis by household income indicated that low-income participants were more likely to be OHIP-14 'cases'. Moreover, among the 'cases', low-income participants were more likely to report an impact on the quality of life. The addition of global ratings of oral health-related quality of life and quality of life provides information of use in understanding the negative consequences of oral disorders.

To assess whether an oral health-related quality of life (OHRQoL)measure showed differential item functioning (DIF) by ethnicity. A simple random sample of 12- and 13-year-old schoolchildren enrolled in the Taranaki District Health Board's school dental service, New Zealand. Each child (n = 430) completed the Child Perception Questionnaire (CPQ(11-14)) in the dental clinic waiting room, prior to a dental examination. The dataset included age, gender, ethnicity, and deprivation status. The general principle of the analytic plan was that equal scores from each CPQ(11-14) item were expected from both non-Mäori and Mäori groups regardless of their ethnic group. Ordinal logistic regression was performed. The dependent variables were the CPQ(11-14) items. The ethnicity group and each CPQ(11-14) domain score were the independent variables. Non-uniform DIF was assessed through adding an interaction term for each CPQ(11-14) sub-scale. Non-uniform DIF was found in two items, one in the Functional Limitations sub-scale and another in the Social Well-being sub-scale. Uniform DIF was found in one item of the Emotional Well-being sub-scale. Both non-uniform and uniform DIF by ethnicity was found in three of 37 items of the CPQ(11-14) questionnaire, showing it is important to perform DIF analysis when applying OHRQoL measures.

Boiko OV, Baker SR, Gibson BJ, Locker D, Sufi F, Barlow, APS, Robinson PG. Construction and validation of the quality of life measure for dentine hypersensitivity (DHEQ). J Clin Periodontol 2010; 37: 973–980. doi: 10.1111/j.1600-051X.2010.01618.x. Aim: To develop and validate a condition specific measure of oral health-related quality of life for dentine hypersensitivity (Dentine Hypersensitivity Experience Questionnaire, DHEQ). Materials and Methods: Questionnaire construction used a multi-staged impact approach and an explicit theoretical model. Qualitative and quantitative development and validation included in-depth interviews, focus groups and cross-sectional questionnaire studies in a general population (n=160) and a clinical sample (n=108). Results: An optimized DHEQ questionnaire containing 48 items has been developed to describe the pain, a scale to capture subjective impacts of dentine hypersensitivity, a global oral health rating and a scale to record effects on life overall. The impact scale had high values for internal reliability (nearly all item-total correlations >0.4 and Cronbach's α=0.86). Intra-class correlation coefficient for test–retest reliability was 0.92. The impact scale was strongly correlated to global oral health ratings and effects on life overall. These results were similar when DHEQ was validated in a clinical sample. Conclusions: DHEQ shows good psychometric properties in both a general population and clinical sample. Its use can further our understanding of the subjective impacts of dentine sensitivity.

Studies of computer-aided learning (CAL) in orthodontics have documented both objective and subjective outcomes; however, to date, no studies have attempted to correlate these 2 outcome measures. The main objective outcome measured was performance on a written test covering material in the orthodontic diagnosis electronic tutorial (ODET) administered to 92 fourth-year undergraduate dental students. The main subjective outcome measured was a 12-statement questionnaire to elicit students' perception of the ODET and CAL as teaching modalities. In the male and female subgroups, a statistically significant difference in mean lecture test scores favoring women (72.46%) over men (67.08%) was observed (P = 0.05). This difference was not observed for mean ODET test scores (P = 0.52). Although responses to the questionnaire were mostly positive, the students are not prepared to replace lectures with CAL tutorials. Responses showed that male students preferred self-instruction as a mode of learning more than female students did (P = 0.05). When linking objective and subjective outcomes, the mean ODET test score had a statistically significant (P = 0.025), but weak, positive correlation (r = 0.243) with self-reported time spent reviewing the ODET but not with any other statement in the questionnaire. Despite a difference in lecture test scores between male and female students, there was no difference in mean ODET test scores between the 2 subgroups. This might be explained by sex differences: male students preferred self-instruction more than female students did. Improved performance on the ODET test was noted for students who reported longer times spent reviewing the tutorial. Because students are not prepared to replace lectures with CAL tutorials, from their perspective, the ODET should continue to be used with traditional modes of learning.