Oral diseases pose a major health burden globally causing pain, discomfort, disfigurement and even death, and are increasing in low- and middle-income countries [1]. “The majority of oral health conditions are: dental caries (tooth decay), periodontal diseases, oral cancers, oral manifestations of HIV, oro-dental trauma, cleft lip and palate, and noma.” [1] “Globally, it is estimated that 2.3 billion people suffer from caries of permanent teeth, and severe periodontal diseases are estimated to affect nearly 10% of the global population.” [1] The prevalence of untreated caries and periodontal disease was high in the general population in Khartoum State, Sudan [2].
Sudan has a population of 45.5 million people, life expectancy at birth is 66.5 years, 35.3% live in urban areas, 60.7% can read and write, and there are 0.26 physicians per 1,000 population [3]. In Sudan, the dentist-to-patient ratio is 1:33,000 [2, 4]. “Relative to the size of the Sudanese population, there are very few dentists and this restricts access to regular dental care. Other factors which influence dental attendance in Sudan include the lack of public funding for oral healthcare and dental insurance schemes to ameliorate the cost of care.” [2]. In an assessment of dental services in urban and rural areas in the Gezira locality in Sudan, a poor provision of dental services in both quantity and quality was found [5]. In Sudan, the health care share of out-of-pocket expenditure is 78.9% (2013) [6]. Households use one 1% of health expenses on dental care [7]. The National Health Insurance Fund (NHIF) covered 43.8% of the Sudanese population at the end of 2016 [8]. People who are not covered by health insurance have to pay user fees in public sector health facilities in Sudan [7]. The “utilization of outpatient dental healthcare is 63% higher for insured people than for the non-insured” in Sudan [7]. The “public sector operates 3,726 family health centers/units, 141 locality hospital and 55 hospitals”, while the private sector, concentrated in major cities, operates 319 health centres and 49 hospitals [7].
According to data from the World Health Survey [9], adults expressing a need for oral health services range from 35% in low-income countries to 60% in lower-middle-income countries. Prompt dental service utilisation (DSU) is needed for the prevention and treatment of oral diseases, and it is therefore important to determine the facilitators and barriers of DSU [10]. However, no national population-based study has been conducted on the prevalence and correlates of DSU in Sudan, a low-income country in north-eastern Africa. In an assessment study on the clinical oral health status among Sudanese adults in Khartoum State, a high prevalence of caries was found, 22.7% had never DSU, 16.7% every two years DSU and 60.6% less than every two years DSU [2]. In a health centre based survey of beneficiaries of Health Insurance Corporation Khartoum State, Sudan (N = 442), 46% had past 12-month DSU [11], and among dental patients in Khartoum (N = 1262), 53.9% has past two years DSU [12],
In a review including studies from 28 countries found a global mean “proportion of individuals regularly/preventively utilizing dental services was 54%.” [13]. In specific countries, the past 12-month dental service utilization (DSU) was 21.4% in 35–44 year-olds and 20.7% in 65–74 year-olds in China [14], in adults is Bejing, 11.3% per year [15], and in Iran 56% (15–64 years) [16]. Some studies have reported the prevalence never-DSU among the general adult population, ranging from 3.3% in Brazil [17] to 73.6% in Nigeria [18], and 86.4% in Indonesia [19]. Furthermore, the national study in Nigeria [18] showed the prevalence of self-reported reasons for DSU, namely, 54.9% for treatment, 24.9% for check-up only, and the remainder for both treatment and check-up, while in two studies in Greece the reasons were 31.7% of the visits were for a regular dental check up [20], and 32.6% reported prevention as the reason for visit [21], and in Khourtum State in Sudan most (> 91%) indicated pain to be the reason for going to the dentist [4].
Predisposing factors of DSU include female sex [10, 12,13,14,15, 19], older age [16, 19, 22], decreasing age [10, 15], no age differences [13], higher educational level [14, 16, 19, 22, 23], and higher household income/wealth [14, 16, 19,20,21,22,23]. Enabling factors of DSU include having medical insurance [14, 15, 22, 23], urban residence [10, 19, 23], short distance to dentist [15], and oral health literacy [13, 15].
Health and lifestyle factors of DSU include better general health status [13], having normal weight [20], having non-communicable diseases [10], never smoking [19], low alcohol use [24], being physically active [20], and having a healthier diet [20]. Perceived need factors of DSU include poor self-rated oral health (SROH) [13,14,15,16, 22], pain in teeth or gum [19, 25], self-reported mouth ulcers [19], more permanent teeth [25], not edentulous, nor severe tooth loss [13], and eating difficulties due to oral problems [26]. The study aimed to investigate the prevalence and associated factors of DSU in a general population-based survey among 18–69 year-old persons in Sudan.
Methods
Participants and procedures
The sample included 7722 adults (18–69 years, 36 years median; interquartile range: 23–43) that participated in the cross-sectional 2016 Sudan Stepwise approach to surveillance (STEPS) Survey [27, 28]. STEPS focus is on “obtaining population-based data on the established risk factors that determine the major disease burden” [27]. “STEPS surveys collect data at three levels: Step 1- Questionnaire-based assessment includes socio-economic data, data on tobacco and alcohol use, nutritional status, and physical inactivity; Step 2- includes simple physical measurements, such as height, weight, waist circumference, and blood pressure; and Step 3- includes biochemical measurements” [27].”
A nationally representative population-based sample was selected using a multistage sampling approach. The 2016 Sudan STEPS survey was conducted from February to December 2016. The study response rate was 88%; further details and data can be accessed [27, 28].
All methods were performed in accordance with the relevant guidelines and regulations.
All methods were carried out in accordance with the Declaration of Helsinki.
The study protocol was approved by the “national Ethical Committee at the Federal Ministry of Health, Sudan” [27, 28]. Informed consent was obtained from all subjects or, if subjects are under 18, from a parent and/or legal guardian [27, 28].
Sample size calculation. In a systematic review and meta-analysis the mean past 12 month DSU was 21.4% [13]. Based on this information, the sample size was calculated with an expected DSU prevalence of 21%, acceptable margin of 5%, confidence level 99.99% and clusters 302; the minimum sample for each cluster is 4, the minimum sample is 1208. In this study we used all 7,722 participants for the analysis.
Measures
The study used the STEPS Survey questionnaire (see Additional file 1) [27, 28].
DSU was assessed with the question,”How long has it been since you last saw a dentist?” Response options were: < 6 months, 6–12 months, > 1 year and < 2 years, > 2 years and < 5 years, ≥ 5 years, and never received dental care [26]. Furthermore, participants were asked, “What was the main reason for your last visit to the dentist?” (Response options ranged from 1 = consultation/advice to 4 = other, see more details in Table 2) [28].
Predisposing factors included age, sex, household income, and highest educational level [28].
Enabling factors included (1) residence status, (2) health care workers advised to “quit using tobacco or don’t start” in the past three years, (3) ever had blood pressure measured by a health care worker? (4) ever had blood sugar measured? and (5) ever had cholesterol (fat levels in blood) measured) [28].
Health and lifestyle factors
Using WHO STEPS standard methodology [27], diabetes was defined as “fasting plasma glucose levels ≥ 7.0 mmol/L, and/or currently taking insulin or oral hypoglycemic drugs,”[27] hypertension (BP) was defined as “systolic BP ≥ 140 mm Hg and/or diastolic BP ≥ 90 mm Hg or currently on antihypertensive medication” (mean of the last two of three readings), raised total cholesterol (TC) (“fasting TC ≥ 5.0 mmol/L or currently on medication for raised cholesterol”), and general overweight/obesity (measured Body Mass Index:”25–29.9 kg/m2 overweight and ≥ 30 kg/m2 obesity”) [28].
Oral health-related behaviours were sourced from two items: 1) “How often do you clean your teeth?” (“1 = never to 7 = twice or more a day”), and 2) “Do you use toothpaste?” [28]
Other health behaviours included past and current tobacco smoking, current smokeless tobacco use, daily fruit and vegetable intake [28], and high, moderate, or low physical activity measured with the “Global Physical Activity Questionnaire (GPAQ).” [29]
Need factors
SROH was sourced from two items, 1) “How would you describe the state of your teeth, and 2) How would you describe the state of your gums?” [28] Poor SROH was defined as “having poor or very poor status of teeth and/or gums, and good oral health as having an average, good,, very good or excellent status of teeth and/or gums”, in line with previous research [30].
Oral health impact (OHI) was sourced from three items, “Difficulty in chewing foods in the past 12 months?” embarrassment about the appearance of teeth in the past 12 months, and “Days not at work because of teeth or mouth?” (“Yes/No”) [28].
Physical symptoms were sourced from the item, “During the past 12 months, did your teeth or mouth cause any pain or discomfort?” (“Yes/No”) [28].
Self-reported number of teeth was measured with the question “How many natural teeth do you have?” Response options were: no natural teeth, 1–9, 10–19 and ≥ 20 teeth [28].
Data analysis
Statistical procedures were conducted with STATA software version 15.0 (Stata Corporation, College Station, Texas, USA), taking into account the multistage sampling design and weighting of the data [28]. Multinomial logistic regression was conducted to estimate the predictors of DSU (> 12 months and past 12 months, with never DSU as the reference category). Variables significant in the simple model were subsequently included in the multivariable logistic model. Missing values were not included in the analysis and p < 0.05 was seen as significant.
