CC BY
0ïDE-156; No. of Pases 6
ARTICLE IN PRESS
Rev Paul Pediatr. 2016;xxx(xx):xxx-xxx
ORIGINAL ARTICLE
Factors associated with caries: a survey of students from southern Brazil
Tâssia Silvana Borges, Natali Lippert Schwanke, Cézane Priscila Reuter, Léo Kraether Neto, Miria Suzana Burgos *
Universidade de Santa Cruz do Sul (UNISC), Santa Cruz do Sul, RS, Brazil Received 24 September 2015; accepted 21 February 2016
KEYWORDS
Dental caries; Epidemiology; Students
PALAVRAS-CHAVE
Cáries dentárias;
Epidemiologia;
Estudantes
Abstract
Objective: To describe the factors associated with dental caries among students from Santa Cruz do Sul, Rio Grande do Sul, Brazil.
Methods: A cross-sectional study was conducted in a random sample of 623 students of both genders, aged 10-17 years old. Tooth decay was performed using the index of the World Health Organization (1997), DMFT (permanent dentition) that expresses the sum of decayed, missing and filled teeth per person. The maternal educational level was rated using criteria of the Brazilian Association of Market Research Companies. The remaining variables were obtained by a structured questionnaire. Poisson regression analysis was used to test the association between variables using robust models and a subsequently adjusted model. Data were expressed as prevalence ratio (PR).
Results: Multivariate analysis identified the following factors related to the experience of dental caries: residence in rural municipalities (PR: 1.15; 95%CI: 1.0-1.3), attending a city school (PR: 3.30; 95%CI: 1.1-9.4) or a state school (PR: 3.40; 95%CI: 1.1-9.6); and having an illiterate mother or a mother that only attended up to the 4th year of school (PR: 1.67; 95%CI: 1.1-2.4) or high school (PR: 1.54; 95%CI: 1.1-2.2).
Conclusions: The presence of caries in students in southern Brazil was associated with residence in rural areas, mother with little education and attendance to a public school. © 2016 Sociedade de Pediatria de Sao Paulo. Published by Elsevier Editora Ltda. This is an open access article under the CC BY license (https://creativecommons.org/licenses/by/4.0/).
Fatores associados à cárie: pesquisa de estudantes do sul do Brasil Resumo
Objetivo: Descrever os fatores associados à cárie dentária em escolares de Santa Cruz do Sul, Rio Grande do Sul, Brasil.
* Corresponding author. E-mail: mburgos@unisc.br (M.S. Burgos).
http://dx.doi.org/10.1016Zj.rppede.2016.02.013
2359-3482/© 2016 Sociedade de Pediatria de Sao Paulo. Published by Elsevier Editora Ltda. This is an open access article under the CC BY license (https://creativecommons.org/licenses/by/4.0/).
^ ARTICLE IN PRESS
Borges TS et al.
Métodos: Um estudo transversal foi realizado em uma amostra aleatoria de 623 estudantes de ambos os sexos, com idade entre 10 a 17 anos. A cárie dentária foi avaliada utilizando-se o índice da Organizado Mundial da Saúde (1997), CPO-D (denticao permanente) que constitui a soma de dentes cariados, perdidos e obturados por pessoa. A escolaridade materna foi avaliada utilizando-se os critérios da Associacao Brasileira de Empresas de Pesquisa de Mercado. As demais variáveis foram obtidas através de um questionário estruturado. A análise de regressao de Poisson foi utilizada para testar a associacao entre as variáveis, utilizando-se modelos robustos e um modelo ajustado posteriormente. Os dados foram expressos como razao de prevalencia (RP).
Resultados: A análise multivariada identificou os seguintes fatores relacionados a experiencia de cárie dentária: residencia em municipios rurais (RP: 1,15; IC95%: 1,0-1,3), frequentar uma escola municipal (RP: 3,30; IC95%: 1,1-9,4) ou estadual (RP: 3,40; IC 95%: 1,1-9,6); e ter uma mae analfabeta ou uma mae que só concluiu até a 4a série do Ensino Fundamental (RP: 1,67; IC95%: 1,1-2,4) ou o ensino médio (RP: 1,54; IC95%: 1,1-2,2).
Conclusoes: A presenca de cárie em alunos no sul do Brasil foi associada com residencia em áreas rurais, mae com baixo nivel educacional e frequentar escola pública. ©2016 Sociedade de Pediatria de Sao Paulo. Publicado por Elsevier Editora Ltda. Esteé um artigo Open Access sob a licenca CC BY (https://creativecommons.org/licenses/by/4.0/deed.pt).
Introduction
According to the World Health Organization (WHO), the prevalence of dental caries among schoolchildren is 90% in some countries.1 In Brazil, the prevalence in children is 53.4% and in adolescents, 56.5%.2 Dental caries is one of the most researched oral diseases3,4 and results from a chronic process that occurs after a certain amount of exposure to a cariogenic diet and to tooth-susceptible microorganisms. Caries is considered a multifactorial condition that is transmitted locally and is one of the most prevalent pathologies in childhood.5,6
Risk factors for dental caries include salivary flow and composition, cariogenic bacteria present, inadequate fluoride exposure, immune components and genetic factors.7"9 However, other factors, such as lifestyle, behavior, hygiene, eating habits, social status and sociodemographic factors, also contribute to the evolution of caries.6,10"12 Oral diseases affect daily activities; among these activities, increased absenteeism13 and decreased performance at school and work have widespread economic and psychological impacts and can lead to significant reductions in individual quality of life.14,15 In this context, this study aimed to describe factors associated with caries among students in Santa Cruz do Sul, Rio Grande do Sul, Brazil.
Method
A cross-sectional study of 623 students of both sexes, aged 10 -17 years old, was conducted from April to December 2012. The sample consisted of students from public and private schools in the city of Santa Cruz do Sul, Rio Grande do Sul, Brazil.
Santa Cruz do Sul has a population of 118,374,000 inhabitants, according to the census of the Brazilian Institute of Geography and Statistics (IBGE).16 In the urban area of the municipality there are 105,190,000 inhabitants, and in the
rural area, 13,184,000 inhabitants. The Human Development Index (HDI) is 0.773. The city currently has 99% of households served by drinking water with adequate fluoridation. The municipality has 64 establishments of the Unified Health System (SUS), 12 Basic Health Units (UBS) (4 in the rural area and 8 in the urban area) and, among them, six have Surgeon Dentists. Ten teams are dedicated to the Family Health Strategy (1 in the rural area and 9 in the urban area) and four of them have oral health team. In 2012, 14,899 registrations were made in primary education (1751 in private schools, in 6958 city public schools, and 6190 in state public schools). In high school, there were 4010 registrations (765 in private schools and 3245 in public schools).17
The reference population for the study consisted of approximately 20,540 students in primary and high schools in the public and private school network of the city of Santa Cruz do Sul, stratified by rural vs. urban areas and, further, by center and periphery: north, south, east or west. The city has a total of 69 schools: eight are private schools, all of them located in the urban area, 30 are city schools ans 31 municipal schools. In the rural area, there are six state schools and 16 city schools.17 In order to calculate the sample size, Epi-Info program (Centers for Disease Control and Prevention, Atlanta, GA, USA, version 7) was used. The prevalence of tooth decay used for the calculation was 56%,2 with 80% power and a standard error of 5%. Based on these parameters, the minimum required sample size was 362 students. When the confounding variables were added to control the effect by 20% and 20% for losses and refusals, the required sample was 522 students.
The inclusion criteria were: informed consent form signed by a parent/guardian; the adolescent was willing and able to conduct an examination of the oral cavity; the adolescent was properly enrolled in the school, and the adolescent was within the age range of 10-17 years. Both genders were included in the study. The adolescents were excluded from the study if they were absent from school at the time of the oral health evaluation or if they did
IllUlfPFPfM AIIIILE IN PRESS
Factors associated with caries
not permit the evaluation or if they did not complete the questionnaires properly. Two attempts of assessment of oral health per student were carried out.
To evaluate dental caries, an examiner conducted the calibration initially, and the kappa test revealed a correlation of K=0.90. Calibration was performed between the examiner of the study and a researcher with extensive prior experience. The assessment of oral health was performed at the university's research laboratory by a previously trained researcher. The assessment followed the protocol of the SB Brazil Project.2 During the oral examination, the student and the researcher remained seated in chairs in front of a window in order to obtain the maximum natural lighting. The mean duration of the dental examination was 10min. The test was conducted with a WHO ballpoint probe and a number 5 dental mirror, all packed in surgical and auto-claved paper. No radiography was performed, emphasizing that no pre-drying and brushing or prophylaxis of the teeth were performed before the examination. All the codes and criteria were recorded on individual records for each student. The index used was the DMFT (decayed, missing and filled/restored teeth) index. The DMFT index measures, in a specified population, the average number per person of: decayed permanent teeth in need of a filling or extraction (D), missing permanent teeth that have been removed as a result of caries (M), and filled permanent teeth (F). Sometimes, the separate components of the DMFT index are used as a measure of service utilization (e.g., the F component is an indication of dental treatment of decayed teeth), and the M component may suggest what type of dental care has or has not been received (i.e., a high M component suggests that teeth were extracted as a result of untreated decay).
The maternal education level was assessed using a questionnaire adapted with the criteria of the Brazilian Association of Market Research Companies (Associacao Brasileira de Empresas de Pesquisa - ABEP).18 Three categories were used: illiterate or up to the 4th year of school, high school education, and higher education. Age of the students was defined by the WHO19 criteria as follows: early adolescence (10-13 years), middle adolescence (14-16 years) and late adolescence (17-19 years).
Oral hygiene was assessed with a questionnaire adapted from Barros and Nahas,20 with questions related to the frequency of flossing and tooth brushing. We also used a self-administered questionnaire on dietary habits proposed by Barros and Nahas,20 with questions related to the frequency of consumption of sweet foods, snacks and soft drinks.
Data analysis was performed using Statistical Package for the Social Sciences (SPSS) software version 20.0 for Windows (IBM Corp. Released 2011, Armonk, NY: IBM Corp, USA). The significance level used was 5%. Data were described by absolute and relative percentages. Chi-square tested the association of dental caries with other variables. Poisson regression analysis was applied to verify the association between the dependent (DMFT>1) and independent variables using robust models; for these models, significance levels of p<0.05 or p<0.20 were adopted. The adjusted model included the variables that were considered significant (p<0.05).
The research project was submitted and approved by the Ethics Committee in Research of the University of Santa Cruz do Sul, under the protocol number 3044/11, in accordance
with the Declaration of Helsinki. All students who participated in the study had informed consent forms on record signed by their parents or guardians.
Results
In total, 623 students with a mean age of 13.5 years were evaluated; among these students, 57.9% were female, 50.1% lived in the urban area, 65.3% studied in state schools, and 59.2% had mothers who were illiterate or who had four or less years of schooling. The students reported consuming sweets and soft drinks 2-6 times per week, and they most frequently consumed chips once per week. Regarding students' oral hygiene habits, 83.1% brushed their teeth 1 —3 times per day, and flossing frequency was reported as ''sometimes'' by 52.0% of the students. Dental caries showed positive associations with area of residence, type of school, maternal level of education and frequency of flossing. The mean DMFT index was 2.5 (Table 1), which means that each child had an average of 2.5 decayed or lost or restored teeth in the mouth at the time of evaluation.
As shown in Table 2, students living in the rural area of the municipality were 25% more likely to develop dental caries (DMFT>1) compared with those living in the urban area. Students attending municipal or State schools had a five-time greater likelihood of developing dental caries compared with those from private schools. Students with mothers who completed no more than the 4th year of schooling were two times more likely to develop dental caries compared with children of mothers who had more education. Nevertheless, students with mothers who had completed high school had an approximately 81% more chance of developing tooth decay compared with students whose mothers had completed higher education. Regarding oral hygiene habits, flossing ''sometimes'' had a 20% protective effect compared on the likelihood of caries, compared to not flossing at all.
Table 3 presents the analysis adjusted for confounding factors. Living in a rural area, having a mother with a lower education level and attending a municipal or state public school were independently associated with the presence of dental caries.
Discussion
This study demonstrated independent associations between students' DMFT >indices and sociodemographic variables such as: living in rural areas, attending municipal or state public schools and being the children of mothers with less schooling.
Descriptive analyses of the mean DMFT (2.5) index indicated good oral health among this population when compared to the Brazilian context. Data from the national oral health survey conducted in 2010 showed that the DMFT index at 12 years old was 2.06; at 15-19 years old, 4.01.2 For World Health Organization, this result is considered of low severity, being within the range of 1.2-2.6,21 which means that on average, each child has 1.2-2.6 teeth decayed, missing or extracted in mouth.
Students living in rural areas had a greater likelihood of developing dental caries compared with students of urban areas. Studies conducted in Greece,22,23 Australia,24
^ ARTICLE IN PRESS
4 Borges TS et al.
Table 1 Characterization of students (n=623).
Total n (%) DMFT>1 n (%) DMFT=0 n (%) p-value*
Sex 0.204
Female 361 (57.9) 237 (65.7) 124 (34.3)
Male 262 (42.1) 159 (60.7) 103 (39.3)
Housing area <0.001
Urban 312 (50.1) 176 (56.4) 136(43.6)
Rural 311 (49.9) 220 (70.7) 91 (29.3)
School type <0.001
Particular 22 (3.5) 03 (13.6) 19(86.4)
State 407 (65.3) 259 (63.6) 148 (36.4)
Municipal 194 (31.1) 134 (69.1) 60 (30.9)
Mother's educational level <0.001
Completed college 57 (9.1) 19(33.3) 38(66.7)
High school 197 (31.6) 119 (60.4) 78 (39.6)
Illiterate or up to the 4th grade 369 (59.2) 258(69.9) 111 (30.1)
Consumption of sweets 0.678
1-3 times per day 141 (22.6) 95 (67.4) 46 (32.6)
2-6 times per week 237 (38.0) 151 (63.7) 86 (36.3)
1 time per week 213 (34.2) 131 (61.5) 82 (38.5)
Never 32 (5.1) 19(59.4) 13 (40.6)
Snack consumption 0.092
1-3 times per day 88 (14.1) 59 (67.0) 29(33.0)
2-3 times per day 210 (33.7) 144 (68.6) 66 (31.4)
1 time per week 270 (43.3) 164 (60.7) 106 (39.3)
Never 55 (8.8) 29 (52.7) 26(47.3)
Soft drink consumption 0.375
1-3 times per day 142 (22.8) 89 (62.7) 53 (37.3)
2-6 times per week 248 (39.8) 167 (67.3) 81 (32.7)
1 time per week 211 (33.9) 128 (60.7) 83 (39.3)
Never 22 (3.5) 12 (54.5) 10(45.5)
Frequency of brushing 0.524
1-3 times per day 518 (83.1) 325 (62.7) 193 (37.3)
4-5 times a day 87(14.0) 60 (69.0) 27(31.0)
1-3 times per week/no brushing 18(2.9) 11 (61.1) 07(38.9)
Flossing 0.002
Yes/daily 154 (24.7) 109 (70.8) 45 (29.2)
Sometimes 324 (52.0) 185 (57.1) 139(42.9)
Never 145 (23.3) 102 (70.3) 43 (29.7)
* p-value, Chi-square test. DMFT>1, decayed, missing and filled/restored teeth; DMFT=0: school caries free.
Pakistan25 and Brazil26,27 showed a higher prevalence of dental caries and treatment needs in schoolchildren from rural areas. This result could be strongly associated with the poor health status and the limited health services access of the inland population, which emphasizes the urgency of focusing attention on these areas to supply their residents with health information and with teams of professionals who are trained to meet their needs.26
In terms of the type of school, public school students were approximately five times more likely to develop dental caries compared with students from private schools. Similarly, a study conducted in Porto Alegre, Brazil,28 showed
that students from the public school system came from families with lower education levels and that students from the private school network came from families with higher incomes. In our study, approximately 59.2% of the students' mothers were illiterate or had at most completed only the 4th year of school, in contrast with 9.1% of students whose mothers had completed higher education. Several studies in the literature have addressed the relationship between the state of oral health with lower income and, consequently, with less educated parents. In most cases, limited access to information and health-related negative behaviors are associated with these findings and special attention should
IhUnffPFPfM AMIIILE IN PRESS
Factors associated with caries
Table 2 Associations between the DMFT>1 index and the following specific variables: housing area, school type, mother's educational level, dietary habits and oral hygiene habits (brushing and flossing frequencies).
be given to this group.12,29"32 In our study, regarding oral hygiene, most of the schoolchildren performed daily tooth brushing (1 —3 times), but 2.9% reported brushing their teeth 1-3 times per week or not brushing their teeth at all. As for flossing, most of the schoolchildren reported using dental floss only sometimes. Poor oral hygiene practices are directly related to oral health conditions, particularly to the development of dental caries.33 A study conducted in Thailand with 1156 students with 6 years old and 1116 students with 12 years old demonstrated a positive association between tooth decay development and poor oral hygiene practices34 Research conducted in Clementina and Gabriel
Table 3 Associations between DMFT>1 and other variables: area of residence, type of school, mother's educational level and oral hygiene habits, adjusted for sex and age.
Variable Adjusted PR p-valuea
(95%CI)
Housing area
Urban 1
Rural 1.15 (1.0-1.3) 0.030
School type
Municipal 3.30 (1.1-9.4) 0.026
State 3.40 (1.1-9.6) 0.022
Particular 1
School education of mother
Illiterate or up to the 4th 1.67 (1.1-2.4) 0.005
High school 1.54 (1.0-2.2) 0.023
Completed college 1
Flossing
Yes/daily 0.97 (0.8-1.1) 0.703
Sometimes 0.80 (0.7-0.9) 0.003
Never 1
PR, prevalence ratio; CI, confidence interval. a Poisson regression with robust adjusted models.
Monteiro, in Brazil, showed that the sooner children began good oral hygiene practices, the lower the prevalence of early dental caries were.35
The limitations of this study are inherent to cross-sectional studies, which do not allow establishing a relationship of cause and effect. However, it must be noted that that the sample was representative of the studied municipality, with random selection of all students from public and private schools, urban areas and rural areas. The results of this study can only be generalized to populations with characteristics similar to the studied adolescents.
In summary, this study demonstrated that students residing in rural areas, students of state and city schools, and students of mothers with less schooling experienced a DMFT>1. Moreover, direct action aimed at implementing educational and preventive programs on the topics of hygiene and self-care is necessary, particularly for parents and school communities in rural areas.
Funding
The study received no funding.
Conflicts of interest
The authors declare no conflicts of interest.
Acknowledgments
We are grateful for the financial support of the Coordination of Improvement of Higher Education and Research (CAPES), through funding by the Program for Support of Graduate Education Private Institutions (PROSUP), and for the grants from
Variable Crude PR (95%CI) p - valuea
Housing area
Urban 1
Rural 1.25 (1.1-1.4) <0.001
School type
Municipal 5.06 (1.7-14.5) 0.003
State 4.66 (1.6-13.3) 0.004
Particular 1
School education of mother
Illiterate or up to the 4th 2.09 (1.4- 3.0) <0.001
High school 1.81 (1.2-2.6) 0.002
Completed college 1
Frequency of brushing
1-3 times per week/no 0.97 (0.6-1.4) 0.9
brushing
4-5 times per day 1.09 (0.9-1.2) 0.2
1-3 times per day 1
Flossing
Yes/daily 1.00 (0.8-1.1) 0.9
Sometimes 0.81 (0.7 9.3) 0.004
Never 1
Consumption of sweets
1-3 times per day 1.13 (0.8-1.5) 0.5
2 -6 times per week 1.03 (0.7-1.4) 0.8
1 time per week 1.07 (0.7-1.4) 0.6
Never 1
Snack consumption
1-3 times per day 1.27 (0.9-1.6) 0.1
2 -6 times per week 1.15 (0.8-1.5) 0.4
1 time per week 1.30 (0.9-1.6) 0.5
Never 1
Soft drink consumption
1-3 times per day 1.14 (0.7-1.7) 0.5
2 -6 times per week 1.11 (0.7-1.6) 0.6
1 time per week 1.23 (0.8-1.8) 0.3
Never 1
PR, prevalence ratio; CI, confidence interval. a Poisson regression with robust (crude) models.
WâÊÊSÊBÊ^ ARTICLE IN PRESS
CNPq-PIBIC, Bic Fapergs and PUIC-UNISC for the graduate
students who helped in the collection of data.
References
1. Petersen PE, Bourgeois D, Ogawa H, Estupinan-Day S, Ndiaye C. The global burden of oral diseases and risks to oral health. Bull World Health Organ. 2005;83:661-9.
2. Secretaria de Atencao a Saude. Secretaria de Vigilancia em Saude. Pesquisa Nacional de Saude Bucal: resultados principais. Brasilia: Ministerio da Saude; 2012.
3. Bonecker M, Pucca Junior GA, Costa PB, Pitts N. A social movement to reduce caries prevalence in the world. Braz Oral Res. 2013;27:5-6.
4. Prazai Dixit L, Shakya A, Shrestha M, Shrestha A. Dental caries prevalence, oral health knowledge and practice among indigenous Chepang school children of Nepal. BMC Oral Health. 2013;13:1-5.
5. Arora A, Scott JA, Bhole S, Do L, Schwarz E, Blinkhorn AS. Early childhood feeding practices and dental caries in preschool children: a multi-centre birth cohort study. BMC Public Health. 2011;11:2-7.
6. Harris J. Dental neglect in children. Paed Dent. 2012;22:476-82.
7. FeatherstoneJD, Adair SM, Anderson MH, BerkowitzRJ, BirdWF, Crall JJ, et al. Caries management by risk assessment: consensus statement, April 2002. J Calif Dent Assoc. 2003;31:257-69.
8. Thomson WM. Dental caries experience in older people over time: what can the large cohort studies tell us? Br Dent J. 2004;196:89-92.
9. Anderson M. Risk assessment and epidemiology of dental caries: review of the literature. Pediatr Dent. 2002;24:377-85.
10. Fejerskov O, Kidd EA. Dental caries: the disease and its clinical management. Copenhagen: Blackwell Monksgaard; 2003.
11.Selwitz RH, Ismail AI, Pitts NB. Dental caries. Lancet. 2007;369:51 -9.
12. Castilho AR, Mialhe FL, Barbosa Tde S, Puppin-Rontani RM. Influence of family environment on children's oral health: a systematic review. J Pediatr (Rio J). 2013;89:116-23.
13. World Health Organization. The World Oral Health Report 2003: continuous improvement of oral health in the 21st century - the approach of the WHO Global Oral Health Programme. Geneva: WHO; 2003.
14. Seirawan H, Faust S, Mulligan R. The impact of oral health on the academic performance of disadvantaged children. Am J Public Health. 2012;102:1729-34.
15. Colak K, Coruh T, Dulgergil MD, Hamidi MM. Early childhood caries update: a review of causes, diagnoses, and treatments. J Nat Sci Biol Med. 2013;4:29-38.
16. Instituto Brasileiro de Geografia e Estatistica - IBGE [homepage on the Internet]. Diretoria de Pesquisas - DPE-Coordenacao de PopulaCcao e Indicadores sociais --- COPIS. Available from: http://www.cidades.ibge.gov.br/xtras/perfil.php?lang=& codmun=431680&search=rio-grandedo-sul|santa-cruz-do-sul [cited 29.01.16].
17. Municipio de Santa Cruz do Sul [homepage on the Internet]. Secretaria de Educacao e Cultura [acessed 29.01.16]. Available from: http://www.santacruz.rs.gov.br/secretarias/ educacao-e-cultura
18. AssociacCao Brasileira de Empresas de Pesquisa. Criterio de Classificacao Economica no Brasil. Brasil: ABEP; 2009.
Borges TS et al.
19. World Health Organization. Young people's health - a challenge for society. Report of a WHO study group on young people and health for all. Geneva: WHO; 1986.
20. Barros MV, Nahas MV. Medidas da atividade física: teoria e aplicacao em diversos grupos populacionais. Londrina: Midio-graf; 2003.
21. World Health Organization. Levantamento epidemiológico básico de saúde bucal: manual de instruyes. 3rd ed. Sao Paulo: Editora Santos; 1991.
22. Oulis CJ, Tsinidou K, Vadiakas G, Mamai-Homata E, Poly-chronopoulou A, Athanasouli T. Caries prevalence of 5, 12 and 15-year-old Greek children: a national pathfinder survey. Community Dent Health. 2012;29:29-32.
23. Panagidis D, Schulte AG. Caries prevalence in 12-year-old Cypriot children. Community Dent Health. 2012;29:297-301.
24. Christian B, Blinkhorn AS. A review of dental caries in Australian Aboriginal children: the health inequalities perspective. Rural Remote Health. 2012;12:1-11.
25. Sufia S, Chaudhry S, Izhar F, Syed A, Mirza BA, Khan AA. Dental caries experience in preschool children: is it related to a child's place of residence and family income? Oral Health Prev Dent. 2011;9:375-9.
26. Bastos RS, Silva RP, Maia-Junior AF, Carvalho FS, Merlini S, Caldana ML, et al. Dental caries profile in Monte Negro, Amazonian state of Rondönia Brazil, in 2008. J Appl Oral Sci. 2010;18:437-41.
27. Antunes JL, Peres MA, de Campos Mello TR, Waldman EA. Multilevel assessment of determinants of dental caries experience in Brazil. Community Dent Oral Epidemiol. 2006;34: 146-52.
28. Maltz M, Barbachan e Silva B. Relaijáo entre cárie, gengivite e fluorose e nível socioeconömico em escolares. Rev Saude Publica. 2001;35:170-6.
29. Chi DL, Rossitch KC, Beeles EM. Developmental delays and dental caries in low-income preschoolers in the USA: a pilot cross-sectional study and preliminary explanatory model. BMC Oral Health. 2013;13:53.
30. Ravera E, Sanchez GA, Squassi AF, Bordoni N. Relationship between dental status and family, school and socioeconomic level. Acta Odontol Latinoam. 2012;25:140-9.
31. Ayele FA, Taye TA, Ayele TA, Gelaye KA. Predictors of dental caries among children 7-14 years old in Northwest Ethiopia: a community based cross-sectional study. BMC Oral Health. 2013;13:2-6.
32. Ferreira SH, Béria JU, Kramer PF, Feldens EG, Feldens CA. Dental caries in 0- to 5-year-old Brazilian children: prevalence, severity, and associated factors. Int J Paediatri Dent. 2007;17:289-96.
33. Dawani N, Nisar N, Khan N, Syed S, Tanweer N. Prevalence and factors related to dental caries among pre-school children of Saddar town, Karachi, Pakistan: a cross-sectional study. BMC Oral Health. 2012;12:2-9.
34. Petersen PE, Hoerup N, Poomviset N, Prommajan J, Watanapa A. Oral health status and oral health behaviour of urban and rural schoolchildren in Southern Thailand. Int Dent J. 2001;51:95-102.
35. Tiano A, Moimaz S, Saliba O, Saliba NA. Dental caries prevalence in children up to 36 months of age attending daycare centers in municipalities with different water fluoride content. J Appl Oral Sci. 2009;17:39-44.
