Abstracts

INTRODUCTION

Overweight and obesity, defined as excess body fat compared to lean body mass, ¹⁹19 . Honne T, Pentapati K, Kumar N, Acharya S. Relationship between obesity/overweight status, sugar consumption and dental caries among adolescents in South India. Int J Dent Hyg. 2012;10(4):240-4. DOI:10.1111/j.1601-5037.2011.00534.x
https://doi.org/10.1111/j.1601-5037.2011... are a growing public-health problem in the world. ¹⁵15 . Gerdin EW, Angbratt M, Aronsson K, Eriksson E, Johansson I. Dental caries and body mass index by socio-economic status in Swedish children. Community Dent Oral Epidemiol. 2008;36(5):459-65. DOI:10.1111/j.1600-0528.2007.00421.x
https://doi.org/10.1111/j.1600-0528.2007... Decreasing physical activity, increasing sedentary lifestyles and dietary changes are factors strongly associated with the development of overweight and obesity. ¹²12 . Dietz WH. The obesity epidemic in young children. Reduce television viewing and promote playing. BMJ. 2001; 322(7282):313-4. DOI:10.1136/bmj.322.7282.313
https://doi.org/10.1136/bmj.322.7282.313... Studies have observed increases in being overweight in childhood and adolescence since the beginning of 2000, ²¹21 . Kantovitz KR, Pascon FM, Rontani RMP, Gavião MBD. Obesity and dental caries – a systematic review. Health Prev Dent. 2006;4(2):137-44. resulting in the increased risk of cardiovascular diseases, respiratory disorders and other chronic diseases during adulthood. ³²32 . Perichart-Perera O, Balas-Nakash M, Schiffman-Selechnik E, Barbato-Dosal A, Vadillo-Ortega F. Obesity increases metabolic syndrome risk factors in school-aged children from an urban school in Mexico City. J Am Diet Assoc. 2007;107(1):81-91. DOI:10.1016/j.jada.2006.10.011
https://doi.org/10.1016/j.jada.2006.10.0...

Diet plays an important role in the increased prevalence of obesity ⁸8 . Cinar AB, Christensen IB, Hede B. Clustering of obesity and dental caries with lifestyle factors among Danish adolescents . Oral Health Prev Dent. 2011;9(2):123-130. due to the higher consumption of foods rich in fat and carbohydrates. ³⁴34 . Sadeghi M, Lynch CD, Arsalan A. Is there a correlation between dental caries and body mass índex for age among adolescents in Iran? Community Dental Health. 2011;28(2):174-7. Overweight or obese children and adolescents reported higher consumption of sugary drinks and foods such as “fast food” compared with those who reported normal weight. ³⁴34 . Sadeghi M, Lynch CD, Arsalan A. Is there a correlation between dental caries and body mass índex for age among adolescents in Iran? Community Dental Health. 2011;28(2):174-7. Besides being directly associated with obesity, eating habits, especially regarding the intake of sucrose, have a well-established causal relationship with tooth decay, along with socio-demographic aspects, such as low socioeconomic status. ²⁷27 . Modéer T, Blomberg CC, Wondimu B, Julihn, Marcus C. Association between obesity, flow rate of whole saliva, and dental caries in adolescents. Obesity (Silver Spring). 2010;18(12):2367-73. DOI:10.1038/oby.2010.63
https://doi.org/10.1038/oby.2010.63...

A systematic review and meta-analysis ⁷7 . Chaffee BW, Weston SJ. Association between chronic periodontal disease and obesity: a systematic review and meta-analysis . J Periodontol. 2010; 81(12):1708-24. DOI:10.1902/jop.2010.100321
https://doi.org/10.1902/jop.2010.100321... published in 2010 identified a positive association between obesity and periodontal disease. However, the relationship between obesity and dental caries is unclear. Dental caries remains the most prevalent problem in oral health and it is associated with pain ⁴4 . Boeira GF, Correa MB, Peres KG, Peres MA, Santos IS, Matijasevich A, et al. Caries is the main cause for dental pain in childhood: findings from a birth cohort. Caries Res. 2012;46(5):488-95 DOI:10.1159/000339491
https://doi.org/10.1159/000339491... and a decrease in quality of life. ¹⁶16 . Goettems ML, Ardenghi TM, Romano AR, Demarco FF, Torriani DD. Influence of maternal dental anxiety on the child’s dental caries experience. Caries Res. 2012;46(1):3-8. DOI:10.1159/000334645
https://doi.org/10.1159/000334645... Because caries is associated with poor dietary habits and inappropriate diets promote obesity, a biologically plausible association between obesity and dental caries has been inferred in the literature. ¹⁴14 . Dye BA, Shenkin JD, Ogden CL, Marshall TA, Levy SM, Kanellis MJ. The relationship between healthful eating practices and dental caries in children aged 2-5 years in the United States, 1988-1994. J Am Dent Assoc. 2004;135(1):55-66. However, the presence of a common factor such as a high-sugar diet, caused by the ingestion of food such as soft drinks, cake, and ice cream, seems to increase the probability of both diseases and seems to be the most acceptable theory to explain the relationship between obesity and dental caries. ²¹21 . Kantovitz KR, Pascon FM, Rontani RMP, Gavião MBD. Obesity and dental caries – a systematic review. Health Prev Dent. 2006;4(2):137-44. The biggest challenge in understanding this relationship is to measure the possible confounding variables (diet and income) and effect modifiers (age, oral hygiene habits and use of fluoridated water) in a standardized manner. ³²32 . Perichart-Perera O, Balas-Nakash M, Schiffman-Selechnik E, Barbato-Dosal A, Vadillo-Ortega F. Obesity increases metabolic syndrome risk factors in school-aged children from an urban school in Mexico City. J Am Diet Assoc. 2007;107(1):81-91. DOI:10.1016/j.jada.2006.10.011
https://doi.org/10.1016/j.jada.2006.10.0...

A systematic review ²¹21 . Kantovitz KR, Pascon FM, Rontani RMP, Gavião MBD. Obesity and dental caries – a systematic review. Health Prev Dent. 2006;4(2):137-44. on the subject was indexed by Bireme, Medline, ISI (Thomson Scientific) and Cochrane Library in 2006, covering the age groups of childhood, adolescence, and adulthood. The exclusion criteria identified 33 articles for reading. At the end of the review, three cross-sectional studies, all performed with children, were identified as having good methodological quality. They presented conflicting results regarding the presence of a positive association between obesity and dental caries. Another systematic review and meta-analysis ¹⁷17 . Hayden C, Bowler JO, Chambers S, Freeman R, Humphris G, Richards D, et al. Obesity and dental caries in children: a systematic review and metaanalysis. Community Dent Oral Epidemiol 2012;41(4):289-308 DOI:10.1111/cdoe.12014
https://doi.org/10.1111/cdoe.12014... including studies published before 2010 indicated the presence of a positive association between obesity and dental caries in permanent dentition without clarifying the direction of this association.

The present study deals with a systematic review in order to use the new evidence to update the literature between 2005 and January 2012 on the subject.

METHODS

A systematic review on obesity and dental caries was performed in the electronic databases of the Medline/PubMed, LILACS, and the Web of Science, between 2005 and January 2012. This review included studies published after 2010, which were not included in the systematic review and meta-analysis published earlier on the subject, new scientific evidence to try to clarify the relationship between obesity and dental caries have been added to this study. The first search used the English terms “dental caries” and “obesity”. These two terms are the same as those used in the systematic review performed on the same subject by Kantovitz & Pascon; Rontani & Gavião ²¹21 . Kantovitz KR, Pascon FM, Rontani RMP, Gavião MBD. Obesity and dental caries – a systematic review. Health Prev Dent. 2006;4(2):137-44. (2006) with articles published between 1984 and 2004. The following keywords were used for the definition of caries: “DMFT index”, “tooth decay”; for the explanatory variable the keywords “waist circumference”, “skinfolds” and “body mass index” were used. These descriptors were found in the articles selected in the first search conducted on the subject. For the combination of descriptors, the logical operators “AND” and “OR” were used.

The process of finding the scientific papers to write the review consisted of four steps. The first was the identification of titles in the databases PubMed, LILACS, and Web of Science. Exclusion criteria used in reading the titles consisted of: review articles, protocols on nutrition and food issues, studies on oral health and diet-specific items and obesity studies related to other oral diseases.

The second stage consisted of two researchers independently reading the eligible abstracts. The search also excluded those items that assessed participants aged six and under, articles published before 2004, articles evaluating specific populations such as schizophrenic patients, and master’s dissertations or PhD theses. The few disagreements that occurred were discussed by the two researchers, who then reached a consensus.

The third stage consisted of reading the articles, applying the same exclusion criteria mentioned above.

In the fourth step, all the references of the selected articles were checked in order to find any study not found in the databases previously consulted by the authors.

The quality of the scientific evidence in the selected articles was assessed using the criteria of Downs & Black ¹³13 . Downs SH, Black N. The feasibility of creating a checklist for the assessment of the methodological quality both of randomised and non-randomised studies of health care interventions. J Epidemiol Community Health. 1998;52(6):377-84. DOI:10.1136/jech.52.6.377
https://doi.org/10.1136/jech.52.6.377... (1998). Of the 27 items proposed by the authors, 18 were selected. Those items evaluating intervention studies were excluded because none of the 28 articles selected for review had used this design. The items excluded from Downs & Black’s classification were: Are the interventions of interest clearly described? Does the study provide estimates of the random variability in the data for the main outcomes? Have all important adverse events that may be a consequence of the intervention been reported? Were the staff, places, and facilities where the patients were treated, representative of the treatment the majority of patients receive? Was an attempt made to blind study subjects to the intervention they have received? Was an attempt made to blind those measuring the main outcomes of the intervention? Was compliance with the intervention/s reliable? Were study subjects randomized to intervention groups? and Was the randomized intervention assignment concealed from both patients and health care staff until recruitment was complete and irrevocable? The articles with ten or more items scored by both evaluators in the review were found to have good scientific evidence. The criteria to consider an article as producing good evidence were given by the study authors. The choice of a cut-off point of ten or more items is due to the fact that the Article evaluated as having good scientific evidence had to have more than 50% of the items from the Downs & Black classification positively evaluated by two researchers of the study. For cases in which there was disagreement about the scores of articles between the two researchers, i.e., one researcher considered the article to have good scientific evidence and the other does not, a new assessment was performed and a consensus reached without the need for a third appraiser’s evaluation.

RESULTS

Initially, 346 titles were identified in PubMed, 21 in LILACS, and 170 in Web of Science. After reading the titles, 81 were selected for reading the abstracts: 66 from PubMed, six from LILACS, and nine from Web of Science. Studies involving participants < 6 years old were excluded after reading the articles. Twenty-eight articles published between 2005 and 2012 were identified. All the references were checked and six articles were found that did not meet the review’s inclusion criteria ( Figure ).

Among the 28 articles, 25 were in English, two in Spanish and one was in Portuguese. Twenty-four studies had a cross-sectional design, three were prospective cohort and one was a case control ( Tables 1 and 2 ); Table 1 lists all studies that did not perform adjusted statistical analysis, while those with adjusted statistical analysis are shown in Table 2 .

The ages evaluated ranged from three to 20. Although one of the exclusion criteria was age < 6 years, few studies have evaluated various age groups including children < 6 years, and therefore, they were included in the review. For those studies that performed separate analyses by age groups, only groups with participants > 6 years were included.

The measure of obesity in the 28 studies was Body Mass Index (BMI), and BMI information was self-reported in two of these studies. ⁹9 . Cinar AB, Murtomaa H. Interrelation between obesity, oral health and life-style factors among Turkish school children. Clin Oral Investig. 2011;15(2):177-84. DOI:10.1007/s00784-009-0368-z
https://doi.org/10.1007/s00784-009-0368-... ^{, 10}10 . Cinar B, Murtomaa H. Clustering of obesity and dental health with lifestyle factors among Turkish and Finnish pre-adolescents. Obes Facts. 2008;1(4):196-202. DOI:10.1159/000145931
https://doi.org/10.1159/000145931... The classification of BMI showed no uniformity. Nine studies used the International Obesity Task Force (IOTF) for age and sex and seven assessed BMI through percentiles developed in the United States to determine the population’s standard weight (Center for Disease Control and Prevention – CDC 2000). Three studies used BMI for age and one used for age and weight. Finally, eight studies were also checked which had other methods for obtaining BMI.

Seventeen studies assessed decay through teeth or decayed, missing, or filled surfaces – DMFT or DMFS, or, by means of DMFT or DMFS, in case of the primary dentition. The dental caries were assessed by interproximal radiographs in two studies, through the teeth or decayed and filled surfaces in four, by means of decayed teeth and interproximal radiographs in one study, by decayed surfaces and interporximal radiographs in another study, and through surfaces or decayed teeth in two studies ( Tables 1 and 2 ).

The positive association between obesity and dental caries in permanent teeth was identified in six studies, a negative association was found in one, and eight showed no association. For studies evaluating mixed dentition (deciduous and permanent), four of them found a positive association, one found positive correlation, and seven showed no association. There was no correlation between obesity and caries in a study in which permanent dentition was analyzed ( Tables 1 and 2 ).

When considering studies for the presence of some type of analysis adjusted for other variables that could confound the association between obesity and dental caries, 15 articles described which variables performed the adjustment. ⁵5 . Brandão IMG, Arcieri, RM, Sundefeld MLM, Moimaz SAS. Cárie precoce: influência de variáveis sócio-comportamentais e do lócus de controle de saúde em um grupo de crianças de Araraquara, São Paulo, Brasil. Cad Saude Publica. 2006;22(6):1247-56. DOI:10.1590/S0102-311X2006000600014
https://doi.org/10.1590/S0102-311X200600... ^{, 8}8 . Cinar AB, Christensen IB, Hede B. Clustering of obesity and dental caries with lifestyle factors among Danish adolescents . Oral Health Prev Dent. 2011;9(2):123-130.

9 . Cinar AB, Murtomaa H. Interrelation between obesity, oral health and life-style factors among Turkish school children. Clin Oral Investig. 2011;15(2):177-84. DOI:10.1007/s00784-009-0368-z
https://doi.org/10.1007/s00784-009-0368-... ^{- 10}10 . Cinar B, Murtomaa H. Clustering of obesity and dental health with lifestyle factors among Turkish and Finnish pre-adolescents. Obes Facts. 2008;1(4):196-202. DOI:10.1159/000145931
https://doi.org/10.1159/000145931... ^{, 15}15 . Gerdin EW, Angbratt M, Aronsson K, Eriksson E, Johansson I. Dental caries and body mass index by socio-economic status in Swedish children. Community Dent Oral Epidemiol. 2008;36(5):459-65. DOI:10.1111/j.1600-0528.2007.00421.x
https://doi.org/10.1111/j.1600-0528.2007... ^{, 19}19 . Honne T, Pentapati K, Kumar N, Acharya S. Relationship between obesity/overweight status, sugar consumption and dental caries among adolescents in South India. Int J Dent Hyg. 2012;10(4):240-4. DOI:10.1111/j.1601-5037.2011.00534.x
https://doi.org/10.1111/j.1601-5037.2011... ^{, 22}22 . Kopycka-Kedzierawski DT, Auinger P, Billings RJ, Weitzman M. Caries status and overweight in 2- to 18-year-old US children: findings from national surveys. Community Dent Oral Epidemiol . 2008;36(2):157-67. DOI:10.1111/j.1600-0528.2007.00384.x
https://doi.org/10.1111/j.1600-0528.2007...

23 . Macek MD, Mitola DJ. Exploring the association between overweight and dental caries among US children. Pediatr Dent. 2006;28(4):375-80. ^{- 24}24 . Marshall TA, Eichenberger-Gilmore JM, Broffitt BA, Warren JJ, Levy SM. Dental caries and childhood obesity: roles of diet and socioeconomic status. Community Dent Oral Epidemiol. 2007;35(6):449-58. DOI:10.1111/j.1600-0528.2006.00353.x
https://doi.org/10.1111/j.1600-0528.2006... ^{, 27}27 . Modéer T, Blomberg CC, Wondimu B, Julihn, Marcus C. Association between obesity, flow rate of whole saliva, and dental caries in adolescents. Obesity (Silver Spring). 2010;18(12):2367-73. DOI:10.1038/oby.2010.63
https://doi.org/10.1038/oby.2010.63... ^{, 29}29 . Narksawat K, Tonmukayakul U, Boonthum A. Association between nutritional status and Dental caries in permanent dentition among Primary schoolchildren aged 12-14 years, Thailand. Southeast Asian J Trop Med Public Health. 2008;40(2):338-44. ^{, 33}33 . Pinto A, Kim S, Wadenya R, Rosenberg H. Is there an association between weight and dental caries among pediatric patients in an urban dental school? A correlation study. J Dent Educ. 2007;71(11):1135-40. ^{, 36}36 . Sánchez-Pérez L, Irigoyen, Zepeda M. Dental caries, tooth eruption timing and obesity: a longitudinal study in a group of Mexican schoolchildren. Acta Odontol Scand. 2010;68(1):57-64. DOI:10.3109/00016350903449367
https://doi.org/10.3109/0001635090344936... ^{, 40}40 . Willerhausen B, Blettner M, Kasaj A, Hohenfellner K. Association between body mass index and dental health in 1,290 children of elementary schools in a German city. Clin Oral Investig. 2007;11(3):195-200. DOI:10.1007/s00784-007-0103-6
https://doi.org/10.1007/s00784-007-0103-... ^{, 41}41 . Willershausen B, Moschos D, Azrak B, Blettner M. Correlation between oral health and body mass index (BMI) in 2071 primary school pupils. Eur J Med Res. 2007;12(7):295-9. Eight studies included adjustments for age and sex, ⁶6 . Cereceda MA, Faleiros S, Ormeño A, Pinto M, Tapia R, Díaz C, et al. Prevalencia de caries en alumnos de educación básica y su asociación con el estado nutricional. Rev Chil Pediatr. 2010;81(1):28-36. DOI:10.4067/S0370-41062010000100004
https://doi.org/10.4067/S0370-4106201000... ^{, 19}19 . Honne T, Pentapati K, Kumar N, Acharya S. Relationship between obesity/overweight status, sugar consumption and dental caries among adolescents in South India. Int J Dent Hyg. 2012;10(4):240-4. DOI:10.1111/j.1601-5037.2011.00534.x
https://doi.org/10.1111/j.1601-5037.2011... ^{, 23}23 . Macek MD, Mitola DJ. Exploring the association between overweight and dental caries among US children. Pediatr Dent. 2006;28(4):375-80. ^{, 27}27 . Modéer T, Blomberg CC, Wondimu B, Julihn, Marcus C. Association between obesity, flow rate of whole saliva, and dental caries in adolescents. Obesity (Silver Spring). 2010;18(12):2367-73. DOI:10.1038/oby.2010.63
https://doi.org/10.1038/oby.2010.63... ^{, 29}29 . Narksawat K, Tonmukayakul U, Boonthum A. Association between nutritional status and Dental caries in permanent dentition among Primary schoolchildren aged 12-14 years, Thailand. Southeast Asian J Trop Med Public Health. 2008;40(2):338-44. ^{, 33}33 . Pinto A, Kim S, Wadenya R, Rosenberg H. Is there an association between weight and dental caries among pediatric patients in an urban dental school? A correlation study. J Dent Educ. 2007;71(11):1135-40. ^{, 36}36 . Sánchez-Pérez L, Irigoyen, Zepeda M. Dental caries, tooth eruption timing and obesity: a longitudinal study in a group of Mexican schoolchildren. Acta Odontol Scand. 2010;68(1):57-64. DOI:10.3109/00016350903449367
https://doi.org/10.3109/0001635090344936... ^{, 41}41 . Willershausen B, Moschos D, Azrak B, Blettner M. Correlation between oral health and body mass index (BMI) in 2071 primary school pupils. Eur J Med Res. 2007;12(7):295-9. two only for sex, ¹⁵15 . Gerdin EW, Angbratt M, Aronsson K, Eriksson E, Johansson I. Dental caries and body mass index by socio-economic status in Swedish children. Community Dent Oral Epidemiol. 2008;36(5):459-65. DOI:10.1111/j.1600-0528.2007.00421.x
https://doi.org/10.1111/j.1600-0528.2007... ^{, 22}22 . Kopycka-Kedzierawski DT, Auinger P, Billings RJ, Weitzman M. Caries status and overweight in 2- to 18-year-old US children: findings from national surveys. Community Dent Oral Epidemiol . 2008;36(2):157-67. DOI:10.1111/j.1600-0528.2007.00384.x
https://doi.org/10.1111/j.1600-0528.2007... and five for consumption of any type of food, such as soft drinks, ¹⁰10 . Cinar B, Murtomaa H. Clustering of obesity and dental health with lifestyle factors among Turkish and Finnish pre-adolescents. Obes Facts. 2008;1(4):196-202. DOI:10.1159/000145931
https://doi.org/10.1159/000145931... ^{, 24}24 . Marshall TA, Eichenberger-Gilmore JM, Broffitt BA, Warren JJ, Levy SM. Dental caries and childhood obesity: roles of diet and socioeconomic status. Community Dent Oral Epidemiol. 2007;35(6):449-58. DOI:10.1111/j.1600-0528.2006.00353.x
https://doi.org/10.1111/j.1600-0528.2006... fruits or snacks between meals, ¹⁰10 . Cinar B, Murtomaa H. Clustering of obesity and dental health with lifestyle factors among Turkish and Finnish pre-adolescents. Obes Facts. 2008;1(4):196-202. DOI:10.1159/000145931
https://doi.org/10.1159/000145931... “fast food”, ¹⁰10 . Cinar B, Murtomaa H. Clustering of obesity and dental health with lifestyle factors among Turkish and Finnish pre-adolescents. Obes Facts. 2008;1(4):196-202. DOI:10.1159/000145931
https://doi.org/10.1159/000145931... and milk, ⁹9 . Cinar AB, Murtomaa H. Interrelation between obesity, oral health and life-style factors among Turkish school children. Clin Oral Investig. 2011;15(2):177-84. DOI:10.1007/s00784-009-0368-z
https://doi.org/10.1007/s00784-009-0368-... as well as daily sugar consumption ¹⁹19 . Honne T, Pentapati K, Kumar N, Acharya S. Relationship between obesity/overweight status, sugar consumption and dental caries among adolescents in South India. Int J Dent Hyg. 2012;10(4):240-4. DOI:10.1111/j.1601-5037.2011.00534.x
https://doi.org/10.1111/j.1601-5037.2011... and “snack” consumption more than three times a day. ²⁹29 . Narksawat K, Tonmukayakul U, Boonthum A. Association between nutritional status and Dental caries in permanent dentition among Primary schoolchildren aged 12-14 years, Thailand. Southeast Asian J Trop Med Public Health. 2008;40(2):338-44.

Among the 28 articles, 13 were considered to have good scientific evidence according to the criteria of Downs & Black. Eight of them with adjusted analysis and five articles without adjusted analysis were considered to be of good scientific quality ( Tables 1 and 2 ).

Of these 13 articles, six found a positive association, showing that individuals with higher BMI values had more caries, and there was no association between obesity and dental caries in the other seven studies ( Tables 1 and 2 ).

DISCUSSION

Between 2005 and 2012, 28 eligible articles which analyzed the relationship between obesity and dental caries were found. After applying the exclusion criteria for the revision and those proposed by Downs & Black, ¹³13 . Downs SH, Black N. The feasibility of creating a checklist for the assessment of the methodological quality both of randomised and non-randomised studies of health care interventions. J Epidemiol Community Health. 1998;52(6):377-84. DOI:10.1136/jech.52.6.377
https://doi.org/10.1136/jech.52.6.377... thirteen studies were shown to have good scientific evidence. However, they did not shed light on the link between obesity and dental caries.

Unlike the systematic review by Kantovitz & Pascon; Rontani & Gavião ²¹21 . Kantovitz KR, Pascon FM, Rontani RMP, Gavião MBD. Obesity and dental caries – a systematic review. Health Prev Dent. 2006;4(2):137-44. (2006), this review excluded studies on individuals < 6 years old, as it has been observed that the use of cariogenic foods have a greater impact on the appearance of dental caries increasing the likelihood of association between obesity and caries, after the age of six. ³⁹39 . Tramini P, Molinari N, Tentscher M, Demattei C, Schulte AG. Association between caries experience and body mass index in 12-year-old French children. Caries Res. 2009;43(6):468-73. DOI:10.1159/000264684
https://doi.org/10.1159/000264684... Moreover, in early childhood there is greater parental control over food intake and oral hygiene practices, which can mean lower prevalence of both diseases. ³⁹39 . Tramini P, Molinari N, Tentscher M, Demattei C, Schulte AG. Association between caries experience and body mass index in 12-year-old French children. Caries Res. 2009;43(6):468-73. DOI:10.1159/000264684
https://doi.org/10.1159/000264684... The opposite is also true. Parents that do not perform preventive oral health behaviors and food control, especially regarding the sugar consumption, increase the chances of caries in the primary dentition, and later in the permanent dentition, concomitantly with the presence of obesity. ⁵5 . Brandão IMG, Arcieri, RM, Sundefeld MLM, Moimaz SAS. Cárie precoce: influência de variáveis sócio-comportamentais e do lócus de controle de saúde em um grupo de crianças de Araraquara, São Paulo, Brasil. Cad Saude Publica. 2006;22(6):1247-56. DOI:10.1590/S0102-311X2006000600014
https://doi.org/10.1590/S0102-311X200600...

Studies that evaluated the association between dental caries and obesity indicate a variety of factors to be discussed in order to understand this relationship. The first issue refers to methods for the diagnosis of both diseases. The main diagnostic method for caries is the visual examination of the teeth or surfaces, and this method was used in most studies. However, this diagnostic method can often lead to lower levels of detection of the disease. Some studies using this method considered only the decayed teeth, not those restored or extracted due to caries. ⁶6 . Cereceda MA, Faleiros S, Ormeño A, Pinto M, Tapia R, Díaz C, et al. Prevalencia de caries en alumnos de educación básica y su asociación con el estado nutricional. Rev Chil Pediatr. 2010;81(1):28-36. DOI:10.4067/S0370-41062010000100004
https://doi.org/10.4067/S0370-4106201000... Other studies ¹1 . Alm A, Fahraeus C, Wendt LK, Koch G, Andersson-Gare B, Birkhed D. Body adiposity status in teenagers and snacking habits in early childhood in relation to approximal caries at 15 years of age. Int J Paediatr Dent . 2008;18(3):189-96. DOI:10.1111/j.1365-263X.2007.00906.x
https://doi.org/10.1111/j.1365-263X.2007... ^{, 2}2 . Alm A, Isaksson H, Fahraeus C, Koch G, Andersson-Gare B, Nilsson M, et al. BMI Status in swedish children and young adults in relation caries prevalence. Swed Dent J. 2011;35(1):1-8. used interproximal radiographs, a method more sensitive to caries diagnosis. Using this method is likely to identify higher prevalence of the disease by detecting caries at earlier stages of cavitation. Using this type of examination for diagnosis in epidemiological surveys is not suitable because it is an expensive method and is primarily used by exposing the study population to examination when there is no clinical indication of disease.

There are also aspects that can interfere with measuring obesity. All studies included in this review measured obesity by BMI. There was no study measuring obesity using other diagnostic methods such as skinfold thickness, waist circumference, waist/hip ratio, or x-ray densitometry (DXA), all of which are more accurate methods for identifying levels of obesity. The probable explanation for this is the ease of implementation, objectivity, and comparability with a BMI reference standard, especially in population studies. ¹⁴14 . Dye BA, Shenkin JD, Ogden CL, Marshall TA, Levy SM, Kanellis MJ. The relationship between healthful eating practices and dental caries in children aged 2-5 years in the United States, 1988-1994. J Am Dent Assoc. 2004;135(1):55-66. The limitation of this index, which does not differentiate between lean body mass and fat mass and therefore often produces false positive results, must be considered prior to the study. The non-use of DXA as a more appropriate method to measure obesity is probably due to the examination cost, which often makes it impossible to use in population studies.

A second point refers to the population’s access to oral health services and the use of fluorinated substances. These two factors are considered as potential effect modifiers that may lead to a weak or negative association between obesity and caries. ¹⁹19 . Honne T, Pentapati K, Kumar N, Acharya S. Relationship between obesity/overweight status, sugar consumption and dental caries among adolescents in South India. Int J Dent Hyg. 2012;10(4):240-4. DOI:10.1111/j.1601-5037.2011.00534.x
https://doi.org/10.1111/j.1601-5037.2011... However, these factors were treated as potential confounders in studies in this review. In the present work, most studies showing an association were performed in European countries where oral health services are organized and available to the public, in addition to various forms of administering fluorinated substances being made available. The lack of association between obesity and dental caries was identified mainly in Latin American countries. Four of these studies were conducted in Brazil at the following locations: Bauru, ³⁵35 . Sales-Peres SH, Goya S, Sant’Anna RM, Silva HM, Sales-Peres C, Silva RP, et al. Prevalência de sobrepeso e obesidade e fatores associados em adolescentes na região centro-oeste do estado de São Paulo (SP, Brasil). Cienc Saude Coletiva. 2010;15 Suppl 2:3175-84. DOI:10.1590/S1413-81232010000800022
https://doi.org/10.1590/S1413-8123201000... Southeastern Brazil, with 6.8 to 8.5% of adolescents studied presenting overweight and obesity; in cities belonging to the state of Paraíba, Northeastern Brazil, ²⁸28 . Moreira PV, Rosenblatt A, Severo AM. Prevalence of dental caries in obese and normal-weight Brazilian adolescents attending state and private schools. Community Dent Health . 2006;23(4):251-3. with 30% participants aged between 12 and 15 obese; in Londrina, ³⁸38 . Tambelini CA, Ramos DM, Poli-Frederico RC, Tomasetti, CSC, Barata, TJE, Maciel SM. Dental caries in adolescents and its association with excess weight and sociodemographic factors in Londrina, Paraná, Brazil. Rev Odonto Cienc. 2010;25(3):245-9. Southern Brazil, with 22.4% of the adolescents aged between 15 and 19 being overweight and obese; and in the city of Recife, Northeastern Brazil, ²⁰20 . Jamelli SR, Rodrigues CS, Lira PI. Nutritional status and prevalence of dental caries among 12-year-old children at public schools: a case-control study. Oral Health Prev Dent . 2010;8(1):77-84. with 12.5% of adolescents aged 12 with overweight and obesity. Some of these cities have used a fluoridated water supply for over 30 years, even though dental services are still not adequately structured to meet most of the population’s needs. The lack of association in studies conducted in Latin America probably addresses socioeconomic and dietary conditions, different factors in countries of these two continents. Dietary habits and income ²⁰20 . Jamelli SR, Rodrigues CS, Lira PI. Nutritional status and prevalence of dental caries among 12-year-old children at public schools: a case-control study. Oral Health Prev Dent . 2010;8(1):77-84. are considered important factors for both dental caries and obesity. Dietary habits related to obesity and low incomes may provide a higher quantity and frequency of sucrose intake, which are important factors in caries etiology. ³⁵35 . Sales-Peres SH, Goya S, Sant’Anna RM, Silva HM, Sales-Peres C, Silva RP, et al. Prevalência de sobrepeso e obesidade e fatores associados em adolescentes na região centro-oeste do estado de São Paulo (SP, Brasil). Cienc Saude Coletiva. 2010;15 Suppl 2:3175-84. DOI:10.1590/S1413-81232010000800022
https://doi.org/10.1590/S1413-8123201000... Higher fat intake and decreased fiber may be associated with increased prevalence of caries and overweight/obesity among individuals with lower socioeconomic conditions. ³3 . Bailleul-Forestier I, Lopes K, Souames M, Azoguy-Levy S, Frelut ML, Boy-Lefevre ML. Caries experience in a severely obese adolescent population. Int J Paediatr Dent. 2007;17(5):358-63. DOI:10.1111/j.1365-263X.2007.00848.x
https://doi.org/10.1111/j.1365-263X.2007... However, other authors reported that excessive consumption of fatty foods has less influence on the development of caries than diets rich in sugar, which could be somewhat responsible for the lack of association between obesity and the presence of caries observed in some studies. ³⁹39 . Tramini P, Molinari N, Tentscher M, Demattei C, Schulte AG. Association between caries experience and body mass index in 12-year-old French children. Caries Res. 2009;43(6):468-73. DOI:10.1159/000264684
https://doi.org/10.1159/000264684...

This review presents some limitations. A small number of studies (five) analyzed longitudinal data. When considering only those studies with good scientific evidence according to the criteria of Downs & Black ¹³13 . Downs SH, Black N. The feasibility of creating a checklist for the assessment of the methodological quality both of randomised and non-randomised studies of health care interventions. J Epidemiol Community Health. 1998;52(6):377-84. DOI:10.1136/jech.52.6.377
https://doi.org/10.1136/jech.52.6.377... (1998), four used longitudinal data. The use of longitudinal data including information on various points of time is important because obesity in early life often leads individuals to change their habits to reduce body weight, resulting in a change in BMI scores. However, the scores for caries by means of DMF can remain high because this index considers caries throughout the individuals’ lives. ³⁹39 . Tramini P, Molinari N, Tentscher M, Demattei C, Schulte AG. Association between caries experience and body mass index in 12-year-old French children. Caries Res. 2009;43(6):468-73. DOI:10.1159/000264684
https://doi.org/10.1159/000264684... Moreover, children identified by parents as obese may be guided to restrict their sugar intake; however, if there is still a high consumption of fats and if their caloric intake is greater than expenditure, they will become overweight. ³⁶36 . Sánchez-Pérez L, Irigoyen, Zepeda M. Dental caries, tooth eruption timing and obesity: a longitudinal study in a group of Mexican schoolchildren. Acta Odontol Scand. 2010;68(1):57-64. DOI:10.3109/00016350903449367
https://doi.org/10.3109/0001635090344936...

The second limitation is the lack of adjustment in several studies for variables such as diet and socioeconomics. These two factors have been cited as associated with both diseases, and they should be considered in studies that aim to explain the relationship between obesity and dental caries. However, of the 28 articles examined, five had some kind of adjustment for diet, and four adjusted for socioeconomic issues.

A third limitation involves using the Downs & Black instrument ¹³13 . Downs SH, Black N. The feasibility of creating a checklist for the assessment of the methodological quality both of randomised and non-randomised studies of health care interventions. J Epidemiol Community Health. 1998;52(6):377-84. DOI:10.1136/jech.52.6.377
https://doi.org/10.1136/jech.52.6.377... (1998) to evaluate the quality of scientific evidence from the studies. This instrument was originally developed to evaluate intervention studies, but it has been used for studies with other designs, excluding some of their items. ²⁶26 . Martins EB; Carvalho MS. Associação entre peso ao nascer e o excesso de peso na infância: revisão sistemática. Cad. Saude Publica. 2006;22(11):2281-300. DOI:10.1590/S0102-311X2006001100003
https://doi.org/10.1590/S0102-311X200600... ^{, 30}30 . Noal RB, Menezes AMB, Macedo SEC, Dumith SC. Childhood body mass index and risk of asthma in adolescence: a systematic review. Obes Rev. 2011;12(2):93-104. DOI:10.1111/j.1467-789X.2010.00741.x
https://doi.org/10.1111/j.1467-789X.2010... ^{, 31}31 . Pacheco AHRN, Barreiros NSP, Santos IS, Kac G. Consumo de cafeína entre gestantes e prevalência do baixo peso ao nascer e da prematuridade: uma revisão sistemática. Cad Saude Publica. 2007;23(12):2807-19. DOI:10.1590/S0102-311X2007001200002
https://doi.org/10.1590/S0102-311X200700... Despite this limitation, it was considered useful for the present review because of its ideas about article quality.

It was not possible to perform a meta-analysis. First, due to the heterogeneity of the studies, particularly the methods used to obtain exposure – obesity of this review, and according to non-submission of primary data by most authors of the articles considered as good scientific evidence. A meta-analysis would help clarify the relationship between obesity and dental caries.

This review identified six studies with good scientific evidence, which observed a positive association between obesity and dental caries in children and adolescents, in contrast to what was described in the review by Kantovitz & Pascon; Rontani & Gavião ²¹21 . Kantovitz KR, Pascon FM, Rontani RMP, Gavião MBD. Obesity and dental caries – a systematic review. Health Prev Dent. 2006;4(2):137-44. (2006). They noted three studies with good scientific evidence, and of these one with positive association in children. Although this review found six studies with a positive association between obesity and dental caries, the causal mechanism remains unclear. It is unknown if the associations actually occurred because there is a direct relationship between obesity and dental caries or if diet, a factor common to both diseases, is responsible for this association. None of the studies was designed to consider all the possible effect modifiers (access to health services, use of fluorides, and oral health habits) and confusion factors (diet and income) from the literature. These results were similar to the recent systematic review and meta-analysis, ¹⁷17 . Hayden C, Bowler JO, Chambers S, Freeman R, Humphris G, Richards D, et al. Obesity and dental caries in children: a systematic review and metaanalysis. Community Dent Oral Epidemiol 2012;41(4):289-308 DOI:10.1111/cdoe.12014
https://doi.org/10.1111/cdoe.12014... although the present study had included articles from the literature published between 2011 and 2012. Thus, the studies identified in the literature provide clues about this relationship and indicate the need for new and more clearly delineated studies.

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