This observational cross-sectional study was conducted from May to September 2020 among 6 to 20 years old subjects with hearing impairment. Samples were selected from two special schools in Gorgan city of Golestan province, the north-eastern part of Iran. The list of special schools, the total number of students in each school, and written permission to perform investigation procedures were obtained from the local Education and Training Office. Here, the hierarchy of gatekeepers, such as the local authority responsible for special schools, managers, and teachers of schools, supported the researcher's access to the fieldwork site and legitimized the study. Besides, written consent was obtained from parents via an electronic signature in the virtual setting (WhatsApp).
A total of 76 children attended these special schools; 61 were in the appropriate age group. All participants were informed about the study aim by the special schools' assistant director before the survey. On the other hand, before the interview, it was established that each participant understood the purpose of the interview and was happy to proceed.
The present study was approved by the Research Ethics Committee of Golestan University of Medical Sciences (IR.GOUMS.REC.1398.343) and performed entirely following Helsinki's Declaration. All participants’ rights were protected. Moreover, the data were handled anonymously and confidentially in all stages of the research. Consequently, all documents were de-identified using a participant code, and the names of individuals were removed.
Data on demographic characteristics, medical history, and hearing impairment severity were collected from archives in the schools. Moreover, each parent take part in a 15–20 minutes’ telephone interview. All interviews were accomplished by a single researcher using topic guide questions utilized in Jin & Daly's study .
Subsequently, students' oral health status was rated (good/ very good, moderate, poor) according to parental response to “How would you describe the health of your child's mouth, teeth, and gums?”. The second section asked parents about oral hygiene practices, e.g., tooth brushing frequency per day and dental floss usage by their children. Besides, previous dental visits and reasons for those visits were asked to obtain their dental care utilization pattern. Finally, a researcher asked about parents’ experienced problems related to the utilization of dental services for their children.
The frequencies of variables were obtained by descriptive statistical analysis. Comparisons of the variables were conducted using Fisher’s exact test or chi-square test, as appropriate. Univariate logistic regression was used to determine which factors significantly associated with oral health status, as defined by odds ratios (ORs) with 95% confidence intervals. P-values less than 0.05 were considered to be statistically significant. All analyses were performed using the statistical software STATA version 16 (Stata Corp, College Station, TX).