BackgroundSudanese children with congenital heart defects (CHDs) were found to have poorer oral health than those without CHDs. The aims of this study were to: describe the patterns of oral-health-related background factors in children with and without CHD and explore any differences, and to evaluate the effects of background factors on caries and gingivitis prevalence and dental services utilisation.MethodsIn this analytical cross-sectional study, caregivers of children aged 3–12 years with (CHD cases n = 111) and without CHDs (Controls n = 182), underwent face-to-face interviews using a structured questionnaire. The questionnaire items covered several oral health background factors (independent variables) including: child’s health status, oral hygiene practices, dental services utilization, mother’s level of education, and caregiver’s perception and awareness of their child’s oral health. The relationship between these factors and occurrence of ‘caries’ and ‘gingivitis’ as well as ‘child’s dental services utilisation’ (dependent variables) were explored using multiple adjusted and hierarchal logistic regression analyses.ResultsCompared with controls, CHD cases had lower frequencies of brushing and use of fluoridated toothpaste, and their caregivers were less knowledgeable about caries. Among CHD cases, the variables (brushing and fluoridated toothpaste use) had significant impacts on caries prevalence (odd ratio (OR) =5.6, 95% confidence interval (CI): 1.4–22.8 and OR = 0.3, 95% CI: 0.1–0.8 for infrequent compared to frequent ones, respectively) as well as the mother’s level of education (OR = 2.6, 95% CI: 1.0–6.4). When differences in background factors were controlled for, the adjusted ORs for caries and gingivitis prevalence in CHD cases compared with controls were 1.8, (95% CI: 1.1–3.2) and 5.3 (95% CI: 2.9–9.4), respectively. Among CHD cases, the child’s age (8–12 years: OR = 11.9, 95% CI: 1.9–71.6), and the mother’s level of education (lower education: OR = 0.2, 95% CI: 0.03–0.9) were significantly associated with the child’s dental services utilisation.ConclusionsLower frequencies of brushing and use of fluoride tooth paste were reported among CHD cases, and brushing had the predominant significant impact on caries prevalence. The child’s age and the mother’s level of education were the main factors affecting the child’s (CHD cases) dental services utilisation.Electronic supplementary materialThe online version of this article (doi:10.1186/s12903-016-0318-5) contains supplementary material, which is available to authorized users.