ORIGINAL ARTICLE
International Dental Journal doi: 10.1111/idj.12103
Trends in dental caries among Brazilian schoolchildren: 40 years of monitoring (1971–2011) Helena Mendes Constante1, Marina Leite Souza2, Jo~ ao Luiz Bastos1 and Marco Aurelio Peres3 1 Department of Public Health, Federal University of Santa Catarina, Florianopolis, Santa Catarina, Brazil; 2Agron^ omica Health Care Center, Florianopolis, Santa Catarina, Brazil; 3Australian Research Centre for Population Oral Health – ARCPOH, School of Dentistry, The University of Adelaide, Adelaide, SA, Australia.
The study aimed to estimate the prevalence, severity, and inequality in the distribution of dental caries in schoolchildren from Florian opolis, Santa Catarina, Brazil, in 2011, and to compare the results with data from previous studies carried out since 1971. All 12- and 13-year-old schoolchildren enrolled in a public school were eligible. Dental caries were assessed according to the World Health Organisation diagnostic criteria. Decayed, missing and filled surfaces and teeth (DMFS/DMFT) indexes, the Significant Caries Index (SiC) and the Gini coefficient (to assess inequalities in the distribution of dental caries) were estimated. The response rate was 82.3% (n = 130). The prevalence of dental caries decreased from 98.0% (95% CI 96.0–100.0) in 1971 to 36.9% (95% CI 28.5–45.3) in 2011. The mean DMFT ranged from 9.2 in 1971 to 0.7 in 2011. The mean DMFS index was 1.2 (95% CI 0.8–1.6) in 2011. The Gini coefficient was 0.624 in 2002 but increased to 0.725 in 2011; the Lorenz curve showed that 70–75% of dental caries attacks was restricted to 20% of the population in 2011. A reduction of 41.2% in the mean SiC index was observed between 2002 (3.4, 95% CI 3.0–3.8) and 2011 (1.9, 95% CI 1.6–2.1). An effective decline in the prevalence and severity of dental caries in schoolchildren was observed throughout 40 years of monitoring. However, a small proportion of the population has experienced most of the caries burden in the recent years studied. Key words: Trends, dental caries, DMF index
INTRODUCTION A remarkable decline in dental caries indexes has been observed in the last decades worldwide1–4. Highincome countries, such as Canada, USA and the UK showed a reduction of 34.8%, 54.2% and 77.4%, respectively, in the DMF (decayed, filled, and missing permanent teeth due to dental caries) indexes for 12-year-old children. In addition, middle-income countries, including Mexico, Brazil and Chile, demonstrated a decline in dental caries indexes of 54.4%, 68.3% and 58.2%, respectively, among schoolchildren5. The decline in dental caries is a result of several social and public health measures, including the effective use of different sources of fluoride and improved general living conditions6. It is important to observe that the above-mentioned decline has been followed by a change in dental caries distribution from a Gaussian to a skewed one, leading to a phenomenon called ‘dental caries polarisation’7,8. Under the context of polarisation, few individuals © 2014 FDI World Dental Federation
have most dental diseases and their peers are cariesfree or show a small amount of dental lesions. The monitoring of trends in dental caries at the population level is important even in the context of caries decline; it is part of an oral health surveillance system, as well as an indirect measure to assess the effectiveness of oral health policies. Few studies have monitored the prevalence and severity of dental caries in the same population group for a long period1–4. In Australia, Armfield et al.1 observed a reduction in dental caries of 79% among schoolchildren over 25 years (1977–2002). Also, in the UK, Anderson4 reported that the mean decayed, missing, filled teeth (DMFT) declined by 80% in 12-year-old students from two schools in Somerset between 1963 and 1988. The city of Florian opolis has been part of a 40-year monitoring study of dental caries in schoolchildren aged 12 years and 13 years. The purpose of this study was to assess the prevalence and severity of dental caries in 2011 and to compare these with data 1
Mendes Constante et al. recorded in previous studies conducted in 1971, 19979, 200210, 200511 and 200912 in schoolchildren from the same school in Florian opolis. Furthermore, this study aimed at describing the inequality in the distribution of dental caries and at classifying the tooth surfaces attacked by dental caries. METHODS The study took place in a state school (Padre Anchieta State School of Basic Education) in the city of Florian opolis, State of Santa Catarina, Brazil. In 2010, Florian opolis had the highest Human Development Index (HDI) (0.86) of the country’s capital and the second highest family income among all Brazilian cities. The school is located in a residential region, which has become a middle-class region, with acceptable living standards, over the last 40 years. The population study comprised all 12- and 13year-old schoolchildren (n = 158) enrolled in the school in 2011. Both examiners were trained and calibrated by a member of the research team (MLS), who was considered to be the gold standard examiner. Details on the methods and procedures of examiner calibration can be found elsewhere13. The gold standard (MLS) was an experienced dental examiner, who was responsible for the collection of clinical data in one of the previous studies9. For the calibration exercise, 24 schoolchildren (not included in the study) aged between 11 years and 14 years were examined to test for inter-examiner reliability. Reliability was assessed through the kappa test on a tooth-by-tooth basis, according to the DMFS index (number of decayed, missing and filled permanent dental surfaces). Intra-examiner reliability was not estimated in this study, given that children were not allowed to spend much time outside the classroom. During the 40 years of monitoring, three diagnostic criteria were used. In 1971 and 1997, Klein and Palmer14 dental caries diagnostic criteria were adopted. A second phase of the study was carried out using the criteria proposed by the World Health Organisation (WHO) in 198715 to evaluate the effects of changing diagnostic criteria on the observed reduction of dental caries16. From 2002 until the present study, the adopted diagnostic criteria were those recommended by the WHO in 199717. All examinations during these 40 years were undertaken at school, under natural light, using plain mouth mirrors and sterilised gauze to remove gross debris. Because of the reduction of dental caries levels over the years, the DMFS was also used in 2009 and in 2011. The DMFS index was based on the WHO 1997 diagnostic criteria for DMFT index17. A tooth surface was considered as ‘decayed’ when a lesion in a pit or fissure or a smooth tooth surface presented an unmis2
takable cavity, undermined enamel, or a detectable softened floor or wall. A filled but still decayed surface was also included in this category. This index also considered further areas with past experience of dental caries, recording those that received restorative dental treatment and those that have been extracted because of caries. To analyse tooth surfaces, the examination started in the occlusal surface, followed by the mesial, buccal, distal and lingual surfaces. To describe dental caries attack by each tooth surface, the surfaces attacked were quantified in each tooth. Then, the percentage was calculated by dividing the number of attacked surfaces by the total evaluated surfaces; the resulting values were later categorised into quintiles. Next, all dental surfaces were categorised as follows: (1) very low attack (first quintile), (2) low attack; (3) medium attack; (4) high attack; and (5) very high attack (fifth quintile). Two indicators of inequality in the distribution of dental caries were used: (1) significant caries index (SiC), which focuses on the proportion of schoolchildren with high experience of dental caries and was calculated by taking the mean DMFT from the highest tertile of the DMFT values in the given population18; and (2) Lorenz curve: which allows the calculation of the Gini coefficient19. This coefficient is represented by the area between the line of equality (diagonal) and the Lorenz curve, varying from 0 to 1. A theoretical value of 0 would occur if every person had exactly the same level of dental caries. A Gini coefficient of 1 would occur if all caries were concentrated in only one individual20. To calculate the Gini coefficients for the past four periods of study, a spreadsheet published by Antunes et al.21 was used. Analyses were performed using STATA v.9 (Stata Corp, College Station, TX, USA). The DMFS index was later converted into the DMFT index to compare the results with previous studies. Descriptive statistics of DMFS and DMFT indexes, including 95% confidence intervals (CI), were estimated. The Mann– Whitney U-test was used to assess differences in the DMFT index according to age and gender. A permission letter was sent to students’ parents or guardians but, owing to a lack of responses, we did not obtained written consent from all parents/guardians. Because of that, the school’s dean and dentist, who are responsible for the school area, authorised the oral examinations at school. All parents or guardians received a written letter about the project and those whose children had dental treatment needs were notified and referred to the nearest health centre. Those parents whose schoolchildren did not have dental treatment needs also received a letter on their participation in the study, which provided oral health advice. The project was approved by the ethics committee for Human Research of the Federal University © 2014 FDI World Dental Federation
Dental caries in Brazilian schoolchildren of Santa Catarina (no. 2229/12), which is in full accordance with the World Medical Association Declaration of Helsinki. RESULTS
Prevalence (%)
From a total of 158 schoolchildren, 13 refused to participate (8.2%), six could not be reached because of school absences (3.8%) and nine were transferred to other schools (5.7%), giving a response rate of 82.3%. The kappa values, calculated for inter-examiner reliability, were not lower than 0.7 and most values were
100 90 80 70 60 50 40 30 20 10 0
98.0 93.7 80.0 57.4 40.9
1971*
1997*
43.5
36.9
1997** 2002*** 2005*** 2009*** 2011*** Year
Figure 1. Trends in the prevalence of dental caries in 40 years of study (1971–2011), among 12- and 13-year-old schoolchildren enrolled in Padre Anchieta Basic School. Florianopolis, Santa Catarina, Brazil, 2012. *Klein and Palmer14 diagnostic criteria, **World Health Organisation (WHO) diagnostic criteria15, ***WHO diagnostic criteria17.
10
higher than 0.9. Differences in caries severity, according to sex and age were not statistically significant (P = 0.3 and P = 0.5, respectively). The prevalence of dental caries over the 40 years of study (Figure 1) decreased from 98.0% (95% CI 96.0–100.0) in 1971 to 93.7% (95% CI 90.0–98.0) in 1997, when the Klein and Palmer14 diagnostic criteria were adopted. Between 2002 and 2011, both according to WHO 1997 diagnostic criteria, the caries prevalence decreased from 57.4% (95% CI 50.0–65.0) to 36.9% (95% CI 28.5–45.3). The average DMFT index was 0.67 (95% CI 0.5– 0.9) in the present study (Figure 2), whereas mean decayed, missing and filled components were 0.41 (95% CI 0.26–0.56), 0.03 (95% CI 0.00–0.06) and 0.22 (95% CI 0.12–0.32), respectively. The mean DMFS index was 2.0 (95% CI 1.18–2.8) in 2009 and 1.2 (95% CI 0.79–1.60) in 2011, and, in the present study, 0.92% of the tooth surfaces of the total surfaces examined were attacked by dental caries: of this value, 64.7%, 25.0% and 10.3% corresponded to decayed, filled and missing surfaces, respectively. Among teeth affected by dental caries, the most attacked tooth surface in both years (2009 and 2011) was the occlusal surface of the first molars (38.5% and 52.9% of all attacked surfaces, respectively, for the years 2009 and 2011) and the least attacked was the buccal surface of the first premolars in 2009 (13.5%) and distal and mesial surfaces of the second
Filled
9.2#
Missing
Decayed
9 8
6.2
DMFT mean
7 6 5 4
3.0
3 1.4
2
0.8
1
0.78
0.67
0 1971*
1997* 1997** 2002*** 2005*** 2009*** 2011*** Year
Figure 2. Mean decayed, missing, filled teeth (DMFT) index, its decayed, missing and filled components and their respective 95% confidence intervals among 12- and 13-year-old schoolchildren enrolled in Padre Anchieta Basic School (Florianopolis, Santa Catarina, Brazil, 2012) in 40 years of study (1971–2011). #Unavailable information about the confidence intervals (95%), *Klein and Palmer14 diagnostic criteria, **World Health Organisation (WHO) diagnostic criteria15, ***WHO diagnostic criteria17. © 2014 FDI World Dental Federation
3
Mendes Constante et al.
Figure 3. Distribution of probabilities of tooth surfaces attack by dental caries in schoolchildren aged 12 and 13 years old enrolled in Padre Anchieta Basic School in 2009 and 2011 (Florianopolis, Santa Catarina, Brazil, 2012).
4
1
3.4 2.2
3
2.0
1.9
2 1 0 2002
2005
2009
2011
Year
Figure 4. Trend of the Significant Caries Index (SiC) of 12- and 13year-old schoolchildren enrolled in Padre Anchieta Basic School from 2002 to 2011 (Florianopolis, Santa Catarina, Brazil, 2012).
upper right premolar in 2011 (both 10.5%) (Figure 3). The lower jaw presented the most attacked surfaces (65.0% and 74.5%, respectively, in 2009 and 2011). Figure 4 presents the SiC over the past four study periods. Between 2002 and 2011, the SiC decreased by 44.1%. Figure 5 provides information on the inequality in the distribution of dental caries (cumulative disease) by displaying the Lorenz curve for the schoolchildren observed (cumulative population). The Gini coefficient was 0.62 in 2002 but reached 0.73 in 2011. DISCUSSION A remarkable decline in the prevalence and severity of dental caries was observed in the 40 years studied (1971–2011). Prevalence decreased by 62.3%, 4
Cumulative disease
Significant Caries Index
5
0.8
2002*
0.6
2005**
0.4
2009***
0.2 2011****
0 0
0.2 0.4 0.6 0.8 Cumulative population
1
Figure 5. Lorenz curve for the decayed, missing, filled teeth (DMFT) distribution of 12- and 13-year-old schoolchildren enrolled in Padre Anchieta Basic School from 2002 to 2011 (Florianopolis, Santa Catarina, Brazil, 2012). *The Gini coefficient was 0.62, **The Gini coefficient was 0.72; ***the Gini coefficient was 0.70; ****the Gini coefficient was 0.73.
whereas severity decreased by 92.7% in the period studied. Although these results cannot be generalised to the entire 12- and 13-year-old population from Florian opolis, the mean DMFT found in the present study was similar to that observed in the city, according to the National Oral Health Survey22. The city of Florian opolis showed the lowest DMFT value at age 12 years (0.77) compared with other Brazilian capitals22. The present study is a surveillance study of dental caries for the past 40 years (1971–2011) in this particular school and although the study design does not allow an assessment of the possible reasons for the decline in dental caries, it is possible to speculate that the fluoridation of water supplies contributed to the © 2014 FDI World Dental Federation
Dental caries in Brazilian schoolchildren reduction of caries observed during the study period. In 1982, the Catarinense Company of Water and Sanitation (CASAN) established the water fluoridation system in the city, currently covering about 95.4% of the population. In addition, the increase in the consumption of fluoridated dentifrices after the end of 1980s9,11 and the improvement in the socioeconomic conditions of Florian opolis may have contributed to the observed decline in dental caries parameters11. The distribution of tooth surfaces attacked by caries in 2009 and 2011 was inspired by a more statistically sophisticated study conducted by Batchelor and Sheiham23. They observed a variation in the caries-related susceptibility of tooth surfaces and, as also observed in the present study, the occlusal surfaces of the first molars were also the most attacked by dental caries. Since the establishment of the oral health goals by the WHO for the year 2000, including a DMFT no higher than 3 at the age of 12 years, nearly 78% (148 of 189) of the countries had reached this goal in 2011 (http://www.mah.se/CAPP/Country-Oral-HealthProfiles/According-to-Alphabetical/Global-DMFT-for12-year-olds-2011/). With this notable achievement, new goals were proposed for 2015, one of which is that the SiC should be
International Dental Journal doi: 10.1111/idj.12103
Trends in dental caries among Brazilian schoolchildren: 40 years of monitoring (1971–2011) Helena Mendes Constante1, Marina Leite Souza2, Jo~ ao Luiz Bastos1 and Marco Aurelio Peres3 1 Department of Public Health, Federal University of Santa Catarina, Florianopolis, Santa Catarina, Brazil; 2Agron^ omica Health Care Center, Florianopolis, Santa Catarina, Brazil; 3Australian Research Centre for Population Oral Health – ARCPOH, School of Dentistry, The University of Adelaide, Adelaide, SA, Australia.
The study aimed to estimate the prevalence, severity, and inequality in the distribution of dental caries in schoolchildren from Florian opolis, Santa Catarina, Brazil, in 2011, and to compare the results with data from previous studies carried out since 1971. All 12- and 13-year-old schoolchildren enrolled in a public school were eligible. Dental caries were assessed according to the World Health Organisation diagnostic criteria. Decayed, missing and filled surfaces and teeth (DMFS/DMFT) indexes, the Significant Caries Index (SiC) and the Gini coefficient (to assess inequalities in the distribution of dental caries) were estimated. The response rate was 82.3% (n = 130). The prevalence of dental caries decreased from 98.0% (95% CI 96.0–100.0) in 1971 to 36.9% (95% CI 28.5–45.3) in 2011. The mean DMFT ranged from 9.2 in 1971 to 0.7 in 2011. The mean DMFS index was 1.2 (95% CI 0.8–1.6) in 2011. The Gini coefficient was 0.624 in 2002 but increased to 0.725 in 2011; the Lorenz curve showed that 70–75% of dental caries attacks was restricted to 20% of the population in 2011. A reduction of 41.2% in the mean SiC index was observed between 2002 (3.4, 95% CI 3.0–3.8) and 2011 (1.9, 95% CI 1.6–2.1). An effective decline in the prevalence and severity of dental caries in schoolchildren was observed throughout 40 years of monitoring. However, a small proportion of the population has experienced most of the caries burden in the recent years studied. Key words: Trends, dental caries, DMF index
INTRODUCTION A remarkable decline in dental caries indexes has been observed in the last decades worldwide1–4. Highincome countries, such as Canada, USA and the UK showed a reduction of 34.8%, 54.2% and 77.4%, respectively, in the DMF (decayed, filled, and missing permanent teeth due to dental caries) indexes for 12-year-old children. In addition, middle-income countries, including Mexico, Brazil and Chile, demonstrated a decline in dental caries indexes of 54.4%, 68.3% and 58.2%, respectively, among schoolchildren5. The decline in dental caries is a result of several social and public health measures, including the effective use of different sources of fluoride and improved general living conditions6. It is important to observe that the above-mentioned decline has been followed by a change in dental caries distribution from a Gaussian to a skewed one, leading to a phenomenon called ‘dental caries polarisation’7,8. Under the context of polarisation, few individuals © 2014 FDI World Dental Federation
have most dental diseases and their peers are cariesfree or show a small amount of dental lesions. The monitoring of trends in dental caries at the population level is important even in the context of caries decline; it is part of an oral health surveillance system, as well as an indirect measure to assess the effectiveness of oral health policies. Few studies have monitored the prevalence and severity of dental caries in the same population group for a long period1–4. In Australia, Armfield et al.1 observed a reduction in dental caries of 79% among schoolchildren over 25 years (1977–2002). Also, in the UK, Anderson4 reported that the mean decayed, missing, filled teeth (DMFT) declined by 80% in 12-year-old students from two schools in Somerset between 1963 and 1988. The city of Florian opolis has been part of a 40-year monitoring study of dental caries in schoolchildren aged 12 years and 13 years. The purpose of this study was to assess the prevalence and severity of dental caries in 2011 and to compare these with data 1
Mendes Constante et al. recorded in previous studies conducted in 1971, 19979, 200210, 200511 and 200912 in schoolchildren from the same school in Florian opolis. Furthermore, this study aimed at describing the inequality in the distribution of dental caries and at classifying the tooth surfaces attacked by dental caries. METHODS The study took place in a state school (Padre Anchieta State School of Basic Education) in the city of Florian opolis, State of Santa Catarina, Brazil. In 2010, Florian opolis had the highest Human Development Index (HDI) (0.86) of the country’s capital and the second highest family income among all Brazilian cities. The school is located in a residential region, which has become a middle-class region, with acceptable living standards, over the last 40 years. The population study comprised all 12- and 13year-old schoolchildren (n = 158) enrolled in the school in 2011. Both examiners were trained and calibrated by a member of the research team (MLS), who was considered to be the gold standard examiner. Details on the methods and procedures of examiner calibration can be found elsewhere13. The gold standard (MLS) was an experienced dental examiner, who was responsible for the collection of clinical data in one of the previous studies9. For the calibration exercise, 24 schoolchildren (not included in the study) aged between 11 years and 14 years were examined to test for inter-examiner reliability. Reliability was assessed through the kappa test on a tooth-by-tooth basis, according to the DMFS index (number of decayed, missing and filled permanent dental surfaces). Intra-examiner reliability was not estimated in this study, given that children were not allowed to spend much time outside the classroom. During the 40 years of monitoring, three diagnostic criteria were used. In 1971 and 1997, Klein and Palmer14 dental caries diagnostic criteria were adopted. A second phase of the study was carried out using the criteria proposed by the World Health Organisation (WHO) in 198715 to evaluate the effects of changing diagnostic criteria on the observed reduction of dental caries16. From 2002 until the present study, the adopted diagnostic criteria were those recommended by the WHO in 199717. All examinations during these 40 years were undertaken at school, under natural light, using plain mouth mirrors and sterilised gauze to remove gross debris. Because of the reduction of dental caries levels over the years, the DMFS was also used in 2009 and in 2011. The DMFS index was based on the WHO 1997 diagnostic criteria for DMFT index17. A tooth surface was considered as ‘decayed’ when a lesion in a pit or fissure or a smooth tooth surface presented an unmis2
takable cavity, undermined enamel, or a detectable softened floor or wall. A filled but still decayed surface was also included in this category. This index also considered further areas with past experience of dental caries, recording those that received restorative dental treatment and those that have been extracted because of caries. To analyse tooth surfaces, the examination started in the occlusal surface, followed by the mesial, buccal, distal and lingual surfaces. To describe dental caries attack by each tooth surface, the surfaces attacked were quantified in each tooth. Then, the percentage was calculated by dividing the number of attacked surfaces by the total evaluated surfaces; the resulting values were later categorised into quintiles. Next, all dental surfaces were categorised as follows: (1) very low attack (first quintile), (2) low attack; (3) medium attack; (4) high attack; and (5) very high attack (fifth quintile). Two indicators of inequality in the distribution of dental caries were used: (1) significant caries index (SiC), which focuses on the proportion of schoolchildren with high experience of dental caries and was calculated by taking the mean DMFT from the highest tertile of the DMFT values in the given population18; and (2) Lorenz curve: which allows the calculation of the Gini coefficient19. This coefficient is represented by the area between the line of equality (diagonal) and the Lorenz curve, varying from 0 to 1. A theoretical value of 0 would occur if every person had exactly the same level of dental caries. A Gini coefficient of 1 would occur if all caries were concentrated in only one individual20. To calculate the Gini coefficients for the past four periods of study, a spreadsheet published by Antunes et al.21 was used. Analyses were performed using STATA v.9 (Stata Corp, College Station, TX, USA). The DMFS index was later converted into the DMFT index to compare the results with previous studies. Descriptive statistics of DMFS and DMFT indexes, including 95% confidence intervals (CI), were estimated. The Mann– Whitney U-test was used to assess differences in the DMFT index according to age and gender. A permission letter was sent to students’ parents or guardians but, owing to a lack of responses, we did not obtained written consent from all parents/guardians. Because of that, the school’s dean and dentist, who are responsible for the school area, authorised the oral examinations at school. All parents or guardians received a written letter about the project and those whose children had dental treatment needs were notified and referred to the nearest health centre. Those parents whose schoolchildren did not have dental treatment needs also received a letter on their participation in the study, which provided oral health advice. The project was approved by the ethics committee for Human Research of the Federal University © 2014 FDI World Dental Federation
Dental caries in Brazilian schoolchildren of Santa Catarina (no. 2229/12), which is in full accordance with the World Medical Association Declaration of Helsinki. RESULTS
Prevalence (%)
From a total of 158 schoolchildren, 13 refused to participate (8.2%), six could not be reached because of school absences (3.8%) and nine were transferred to other schools (5.7%), giving a response rate of 82.3%. The kappa values, calculated for inter-examiner reliability, were not lower than 0.7 and most values were
100 90 80 70 60 50 40 30 20 10 0
98.0 93.7 80.0 57.4 40.9
1971*
1997*
43.5
36.9
1997** 2002*** 2005*** 2009*** 2011*** Year
Figure 1. Trends in the prevalence of dental caries in 40 years of study (1971–2011), among 12- and 13-year-old schoolchildren enrolled in Padre Anchieta Basic School. Florianopolis, Santa Catarina, Brazil, 2012. *Klein and Palmer14 diagnostic criteria, **World Health Organisation (WHO) diagnostic criteria15, ***WHO diagnostic criteria17.
10
higher than 0.9. Differences in caries severity, according to sex and age were not statistically significant (P = 0.3 and P = 0.5, respectively). The prevalence of dental caries over the 40 years of study (Figure 1) decreased from 98.0% (95% CI 96.0–100.0) in 1971 to 93.7% (95% CI 90.0–98.0) in 1997, when the Klein and Palmer14 diagnostic criteria were adopted. Between 2002 and 2011, both according to WHO 1997 diagnostic criteria, the caries prevalence decreased from 57.4% (95% CI 50.0–65.0) to 36.9% (95% CI 28.5–45.3). The average DMFT index was 0.67 (95% CI 0.5– 0.9) in the present study (Figure 2), whereas mean decayed, missing and filled components were 0.41 (95% CI 0.26–0.56), 0.03 (95% CI 0.00–0.06) and 0.22 (95% CI 0.12–0.32), respectively. The mean DMFS index was 2.0 (95% CI 1.18–2.8) in 2009 and 1.2 (95% CI 0.79–1.60) in 2011, and, in the present study, 0.92% of the tooth surfaces of the total surfaces examined were attacked by dental caries: of this value, 64.7%, 25.0% and 10.3% corresponded to decayed, filled and missing surfaces, respectively. Among teeth affected by dental caries, the most attacked tooth surface in both years (2009 and 2011) was the occlusal surface of the first molars (38.5% and 52.9% of all attacked surfaces, respectively, for the years 2009 and 2011) and the least attacked was the buccal surface of the first premolars in 2009 (13.5%) and distal and mesial surfaces of the second
Filled
9.2#
Missing
Decayed
9 8
6.2
DMFT mean
7 6 5 4
3.0
3 1.4
2
0.8
1
0.78
0.67
0 1971*
1997* 1997** 2002*** 2005*** 2009*** 2011*** Year
Figure 2. Mean decayed, missing, filled teeth (DMFT) index, its decayed, missing and filled components and their respective 95% confidence intervals among 12- and 13-year-old schoolchildren enrolled in Padre Anchieta Basic School (Florianopolis, Santa Catarina, Brazil, 2012) in 40 years of study (1971–2011). #Unavailable information about the confidence intervals (95%), *Klein and Palmer14 diagnostic criteria, **World Health Organisation (WHO) diagnostic criteria15, ***WHO diagnostic criteria17. © 2014 FDI World Dental Federation
3
Mendes Constante et al.
Figure 3. Distribution of probabilities of tooth surfaces attack by dental caries in schoolchildren aged 12 and 13 years old enrolled in Padre Anchieta Basic School in 2009 and 2011 (Florianopolis, Santa Catarina, Brazil, 2012).
4
1
3.4 2.2
3
2.0
1.9
2 1 0 2002
2005
2009
2011
Year
Figure 4. Trend of the Significant Caries Index (SiC) of 12- and 13year-old schoolchildren enrolled in Padre Anchieta Basic School from 2002 to 2011 (Florianopolis, Santa Catarina, Brazil, 2012).
upper right premolar in 2011 (both 10.5%) (Figure 3). The lower jaw presented the most attacked surfaces (65.0% and 74.5%, respectively, in 2009 and 2011). Figure 4 presents the SiC over the past four study periods. Between 2002 and 2011, the SiC decreased by 44.1%. Figure 5 provides information on the inequality in the distribution of dental caries (cumulative disease) by displaying the Lorenz curve for the schoolchildren observed (cumulative population). The Gini coefficient was 0.62 in 2002 but reached 0.73 in 2011. DISCUSSION A remarkable decline in the prevalence and severity of dental caries was observed in the 40 years studied (1971–2011). Prevalence decreased by 62.3%, 4
Cumulative disease
Significant Caries Index
5
0.8
2002*
0.6
2005**
0.4
2009***
0.2 2011****
0 0
0.2 0.4 0.6 0.8 Cumulative population
1
Figure 5. Lorenz curve for the decayed, missing, filled teeth (DMFT) distribution of 12- and 13-year-old schoolchildren enrolled in Padre Anchieta Basic School from 2002 to 2011 (Florianopolis, Santa Catarina, Brazil, 2012). *The Gini coefficient was 0.62, **The Gini coefficient was 0.72; ***the Gini coefficient was 0.70; ****the Gini coefficient was 0.73.
whereas severity decreased by 92.7% in the period studied. Although these results cannot be generalised to the entire 12- and 13-year-old population from Florian opolis, the mean DMFT found in the present study was similar to that observed in the city, according to the National Oral Health Survey22. The city of Florian opolis showed the lowest DMFT value at age 12 years (0.77) compared with other Brazilian capitals22. The present study is a surveillance study of dental caries for the past 40 years (1971–2011) in this particular school and although the study design does not allow an assessment of the possible reasons for the decline in dental caries, it is possible to speculate that the fluoridation of water supplies contributed to the © 2014 FDI World Dental Federation
Dental caries in Brazilian schoolchildren reduction of caries observed during the study period. In 1982, the Catarinense Company of Water and Sanitation (CASAN) established the water fluoridation system in the city, currently covering about 95.4% of the population. In addition, the increase in the consumption of fluoridated dentifrices after the end of 1980s9,11 and the improvement in the socioeconomic conditions of Florian opolis may have contributed to the observed decline in dental caries parameters11. The distribution of tooth surfaces attacked by caries in 2009 and 2011 was inspired by a more statistically sophisticated study conducted by Batchelor and Sheiham23. They observed a variation in the caries-related susceptibility of tooth surfaces and, as also observed in the present study, the occlusal surfaces of the first molars were also the most attacked by dental caries. Since the establishment of the oral health goals by the WHO for the year 2000, including a DMFT no higher than 3 at the age of 12 years, nearly 78% (148 of 189) of the countries had reached this goal in 2011 (http://www.mah.se/CAPP/Country-Oral-HealthProfiles/According-to-Alphabetical/Global-DMFT-for12-year-olds-2011/). With this notable achievement, new goals were proposed for 2015, one of which is that the SiC should be
