Dental caries and periodontal diseases in Mozambique

Objective: To determine the rate of dental caries and periodontal rates in Mozambican population. Material and Methods: The sample size was 722, categorized in age groups of 6,12, 15-19 and 35-44 in public schools and markets randomly selected in five provinces of Mozambique (Maputo, Gaza, Manica, Tete and Zambezia), in urban and rural areas. Clinical examinations were performed by calibrated examiners using WHO, DMFT/dmft and CPI indexes. Data analysis was descriptive and analytical, using a Chi-square test and Pearson's correlation (P <0.05). Results: The adults aged 35-44 presented higher dental caries (DMFT=1.94) than those aged 6 years (dmft = 1.16), 12 years (DMFT=0.60), and 15-19 years (DMFT=0.87). Dental caries was more prevalent in urban area (1.89) than rural area (1.33) with statistical difference p=0.004. The dental caries was the highest at Manica Province n=68 (85%) and lowest in Tete Province n=70 (31%). Regarding to periodontal status, the most prevalent disease, was Calculus in adults of 35-44 n=95 (59.4%), and the prevalence of individual free of periodontal disease was n=182 (34.3%). Conclusion: When assessing this population for dental caries and periodontal status, the 35-44 years old presented the highest rate of both diseases at all age.


Introduction
Data on oral health in Mozambique are scarce. The data obtained in this research are very significant for Mozambique, due to the need of information for decision making and management of financial resources. In additional, the last national epidemiological survey in Mozambique occurred in 1978. This is a study of prevalence of dental caries and periodontal disease according to the standard ages defined by the WHO, 6, 12, 15-19 and 35-44 years of age. This study has clinical relevance because it offers an estimate of the stages of dental caries and periodontal disease throughout the life cycle.
With the data acquired from this study, strategies for controlling these diseases can be implemented, particularly in children and adolescents.
According to Frencken et al, in the last five decades, the world is trying to reduce dental caries and periodontitis (Frencken et al., 2017). Nevertheless, a large part of the world's population still suffers from these two oral diseases, which are the main causes of tooth loss (Marcenes & Bernabé, 2021). Dental caries is still the most widespread chronic and prevalent oral disease in worldwide, interfering with quality of life (Frencken et al., 2017;Pitts et al., 2017;Tinanoff et al., 2019). It is a multifactorial disease with a complex interaction of cultural, social, behavioural, nutritional and biological risk factors associated with its initiation and progression. Other factors include poor oral hygiene (Gupta, Bray, Kumar, & Johnson, 2017;Sampson, 2020) and low maternal education (Haque et al., 2016;Vollmer, Bommer, Krishna, Harttgen, & Subramanian, 2017).
The DMFT levels vary considerably, from less than 1.0 in Ghana and Guinea-Bissau to over 4.0 in Gabon and Mauritius.
Additionally, local studies show a rapid increase in the incidence of the disease in both urban and rural populations. Most cases of tooth decay remain untreated (Organization, 2016).
In 2010, untreated caries in permanent teeth was the most prevalent condition worldwide, affecting 2.4 billion people, and untreated caries in deciduous teeth was the 10 th most prevalent condition, affecting 621 million children worldwide. The global age-standardized prevalence and incidence of untreated caries remained static between 1990 and 2010. Evidence shows that the burden of untreated caries is shifting from children to adults, with 3 peaks in prevalence at ages 6, 25, and 70 years old (Kassebaum et al., 2015). According to Msyamboza et al., estimated the prevalence of dental caries in Malawi, was 20.3 % in children and 49.1 % in adults and low number of people with filled teeth which was present in only 10 % of adults aged 35 or more, due to inadequate availability or lack of restorative or preventive dental care and treatment (Msyamboza et al., 2016).
Periodontitis, is the second most prevalent oral disease and cause of tooth loss in the world. Severe periodontitis was the sixth most prevalent condition affecting 10.8%, 743 million people aged 15-99 worldwide. The most common and simple form of periodontal disease is gingivitis, which its risk factors includes poor oral hygiene, tobacco use, excessive alcohol consumption, stress, poor general health, diabetes mellitus, and HIV (Frencken et al., 2017).
The aim of the present study was to determine the dental caries and periodontal status in Mozambican populations, in urban and rural area of five provinces of Mozambique in the year 2015.

Methodology
This cross-sectional study followed the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) guidelines.

Ethical aspects
The protocol was approved by the National Committee of Bioethics of Mozambique Health, protocol Ref. n o 214/CNBS/13, (annex). Informed consent forms were signed by the guardian before the oral examination. The examination was performed in 2015, and the children with dental problems were referred to the public dental service.

Study Location
The study was conducted in Mozambique, a country located in the south-eastern strip of the African Continent. With a surface area of 799,380 km 2 , it is political-administrative divided into 11 provinces (Estatística & Saúde, 2013). Five provinces, namely, Maputo, Gaza, Manica, Tete e Zambezia, were cluster randomly selected.

Sampling
Mozambique had a population of 26,423,623 million people, approximately 70% of whom live in rural areas. More than half of the population (52%) is in the 0 to 18 year age group and 20% in the 6 to 12year age group (Estatística & Saúde, 2013). The sample size was 722, categorized in age groups of 6, 12, 15-19 and 35-44 years in public schools and markets Research, Society and Development, v. 11, n. 1, e46511125221, 2022 (CC BY 4.0) | ISSN 2525-3409 | DOI: http://dx.doi.org/10.33448/rsd-v11i1.25221 4 randomly selected in those five provinces. Schools and markets were sampled by conglomerates, three rural and three urban schools per province. Therefore, the sample was selected using the probabilistic method, called conventional. The choice of this method was due to the fact that the name infers, for convenience reasons, ease of obtaining, limited budget, availability of time, as well as being the most recommended for experimental research. The formula used to determine sample size was proportional estimation. The 95% confidence interval was applied, with a 2% margin of error, 50% success rate (p) and 50% failure rate. All volunteers were included in these age groups, of which, who signed informed consent, and without any pathology that interferes. All volunteers outside the above age groups with or without oral pathologies were excluded.

Calibration
Eleven examiners, dentist from each province, performed theoretical and practical activities including discussions on diagnosis criteria of dental caries oriented by two professors from University of Western Cape, South Africa. Approximately 10% of the sample was re-examined in order to verify the intra-examiner reproducibility. The Kappa score for intra-examiner agreement expressed was 0.90 (93.75%). This value indicated reliability within acceptable limits.

Examination methodology
Clinical examinations were performed by calibrated examiners using World Health Organization, DMFT and dmft indexes. From eleven calibrated examiners, only five performed clinical examination, under natural light, using CPI probes ('ball point') and #5 mirrors. Based in WHO Basic methods, Dental caries was recorded using the DMFT/dmft (total of decayed, missing, and filled teeth) and CPI (Community Periodontal Index), according to the WHO diagnostic criteria (Organization, 2013).

Data analyses
The descriptive and analytical approaches were used for data analysis in a personal computer, using SPSS 20.
Descriptive results were analyzed as relative frequencies. The bivariate analysis was to test association between urban and
However, caries experience expresses that the largest proportion is the decayed component (41.0%), followed by the missing component (20.5%) and at last filled (1.4%). Such results denote deficiency in the assistance services of oral health, mainly, by the analysis of the filled component (Table 1). The rate of dental caries was the highest at Manica Province n=68 (85%), followed by Zambezia n=83(68.8%) and lowest in Tete Province n=70 (31.0%), (Table 2).

Discussion
Recent studies in developing countries showed that the prevalence and severity of dental caries have increased with industrialization and exposure to western diets. Data from 20 countries of the Eastern Mediterranean Region (EMRO) showed that the average number of decayed, missing, and/or filled teeth (DMFT) among 12-y-olds ranges from 0.4 to 4.4. Abid found a higher prevalence and severity of dental caries in the primary than in the permanent dentition among 6-y-olds (Abid et al., 2015). These findings match with those reported in the present study. According to Fonseca caries in primary teeth are associated with early protein-energy malnutrition (da Fonseca, 2017 (Bernabé & Marcenes, 2020). In most countries, more than 90% of caries remain untreated (Dye, 2017). These findings were also in agreement with the outcomes found in this study. children of 6 years old and 980 adolescents of 12 years old, revealed that the dmft/DMFT index was, 2.6, 0.8, respectively (Hobdell & Cabral, 1980). Another research carried out in Mozambique in 1989, comprised 575 children at 11-13 years old and 239 adults at 25-34 years old and 45-54 years old from urban and rural areas of Maputo Province, showed that, the experience of caries in children was less in rural area, 23%, than in urban area, 65%. In adults was also less at rural area at age 25-34 years old, 69% DMFT 3,7 and 94% DMFT 7.9 at 45-54 years old, and more in the urban group aged 25-34 years, with caries prevalence at 93% and DMFT 8.1 (Olsson, Segura-Bernal, & Tanda, 1989).

CPI
A study including Mozambique, Uganda and Tanzania in 1997 compared the dmft of 910 children aged 5 to 7 years.
Mozambique presented the lowest dmft of the three countries. Both children in suburban and rural Mozambique had lower rates than in the other two countries. Only children from the urban area presented dmft of 4.2, higher than Tanzania 3.8 and lower than Uganda 5.5 (Lalloo, Hobdell, Mosha, Mboli, & Tanda, 1999).
Another at urban area, and attributed to sugar consumption, 80% in urban and 20% in rural area (Hobdell, 1981) as well as the present study found more experience of caries at urban area, at age of 6. In 1989, Mozambican research also found more prevalent in urban area, 65%, than rural area, 23%, associated to exposure to markets, and cariogenic factors that occurred in urban areas.
In controversy, Mapengo et al, found that children in urban school had less dental caries than children in sub-urban schools and both presented poor oral hygiene. Malnutrition was more in sub-urban schools than in urban schools, and the frequency of sugar consumption was higher among urban children compared to suburban schools (Hobdell & Cabral, 1980).
Evaluating by provinces, Manica had higher prevalence at age 6 years, and Zambezia at age 12 years. Tete was the province with the lowest prevalence in both ages. This may be justified by the presence of high fluoride content in water in previous years (M. Mapengo et al., 2009).
The three surveys conducted in Mozambique at age 12-year, in 1980, (Hobdell & Cabral, 1980) 1989, (Olsson et al., 1989), 2009(M. A. A. Mapengo et al., 2010 and present study, presented DMFT mean, 0.8, 2.09, 0.99 and 0.60 respectively, showing stability from the last research, as well as, for age of 6-year old, in 1980, 1998, 1999 and present study, were also stable, 2.6, 3.2, 1.6 and 1.16, respectively. Calculus was most common periodontal disease, and more prevalent in rural area than urban area, it believes is due to limited access to conventional oral hygiene instruments. The current study found low gingivitis or bleeding (5.8%) in comparison with studies carried out in Mozambique in 1980 (Hobdell & Cabral, 1980) where children at 6 and 12 years old presented 97 and 96% prevalence of gingivitis, respectively. This prevalence was high in Niassa (99%), Tete (100%), Zambezia (98%) and low in Maputo (88%). Calculus was found in 42% at age 6, and 64% at age 12 years old, quite same as in this study, (50.2%). The prevalence of gingival inflammation is very high in several African countries and affects all age groups (Chikte et al., 2019;Tefera & Bekele, 2020). Regarding pocket depth, Chikte et al., evaluated 951 individuals in south Africa, where, over 50% of the subjects had shallow pockets (4-5 mm), and almost 6% had deep pockets (Chikte et al., 2019).
The WHO target at age 5 years for year 2000, was 90% free of caries, such has not been achieved, prevalence was 39.6% of individuals with dental caries experience. At age 12, the global age for monitoring dental caries, the WHO goal was an average DMFT <1 which was achieved, with a mean of DMFT=0.60. The goal for teenagers is 0% of teeth lost at 18, was not achieved, with prevalence of 15.8% of missing teeth. Among adults, 57.5% of edentulous people were identified, which goes against the WHO recommendation, which provides for a maximum of 2% of edentulous people aged 35-44 years. Access to restorative services is almost non-existent, which results in an adult population with decayed, not filled and consequently missing teeth.
The limitations in this study were related with small sample. Further studies should be followed up the groups to relate the cause-effect. On the other hand, the strengths of our research include the fact that there is lack of recent studies covering other provinces of Mozambique.

Conclusion
In conclusion, the mean of oral diseases was low. DMFT/dmft mean were 1,66 in almost half of people. Adults of 35-44 years old presented the highest prevalence dental caries than age of 6, 12 and 15-19 in all provinces, as well as, for periodontal disease. Manica province presented highest prevalence of dental and periodontal diseases than other provinces. The decayed component is the most prevalent in all age groups, 6, 12, 15-19 and 35-44 years old and followed by missing.