INTRODUCTION
Dental caries is the most common condition in the oral cavity and is described as a sequence of processes that destroy the hard tissues that make up the dental organs 1,2. It is a chronic and transmissible disease that affects people of different ages 3. It is estimated that 37% to 59% of adolescents between 12 and 19 years of age suffer from caries in the permanent dentition, especially in low-income hispanics 4,5. One of the dental organs most affected by caries is the first permanent molar 6. This organ has no temporary predecessor and erupts at six years of age on average, which leaves it exposed to the exogenous agents of the oral environment 7,8.
Morbidity of this dental organ among adolescents is high in different regions of the world. In Asia and the Middle East, a prevalence of 54% to 83% has been found 9,10,11. In South America, 14% to 58% is reported among adolescents in public and private schools 12,13,14. In schools in Cuba, it affects 30% to 74% 15,16; and Mexico, the caries experience of 43% is reported among adolescents in some communities 17. The Epidemiological Surveillance System for Oral Pathologies (SIVEPAB) estimates that 26% of children and adolescents under one year to 19 years of age are free of caries 18
By consensus, it has been documented that the main etiology for the appearance of caries among adolescents is poor oral higiene 1,5,19. Other studies mention cariogenic diet 1, malpositions 1, lack of social security 13, schooling 13, ethnicity 14, presence of gingival disease 14, level of education 15, and level of knowledge of the parents 15. In terms of gender, a slight predilection is described in females with a range of 46% to 88% 9,16,17,19.
Regarding the most affected quadrant, the lower left first molar has a greater degree of involvement with a range of 14% to 28% 13,15,16,17. Harmful habits at an early age, such as smoking and alcoholism, increase the risk of caries 20,21.
A balanced diet, efficient oral hygiene, fluoride topicalization and visits with health professionals ensure the reduction of oral Diseases 14,22,23. It is important to know the factors associated with severe caries in permanent first molars. There are guidelines established through the Mexican Official Standard 013 of the Ministry of Health 24, for the prevention and control of oral diseases. This promotes preventive health education in public and private dental services in order to reduce oral disease rates. The promotion of oral health in adolescents helps to avoid premature loss of dental organs 25.
In our region there is no study that deals with the classification of caries in severe stages in the adolescent population. The aim of the study was to estimate the prevalence of severe caries of the first permanent molar and to identify associated factors among adolescents from a public high school in Acapulco, Guerrero state, Mexico.
MATERIAL AND METHODS
Cross-sectional study among adolescents of Secondary School No.6 from Acapulco, during August 2019 to February 2020. A sample of 186 adolescents was obtained, using the finite population formula with a power of 95% and a margin of error of 5%, out of a universe of 384 adolescents. Based on the exclusion criteria, four with orthodontic treatment, two with an absent molar, three who refused to participate and four incomplete questionnaires were eliminated. The final total sample was 173 adolescents with four permanent first molars without restorations and structural or morphological alterations on the occlusal surface.
The measuring instrument was a 21-item self-administered questionnaire validated by a round of experts 26. The questionnaire was administered to the adolescents in the classroom, followed by a clinical oral examination, where forms were filled out to record the clinical observation of the first molars. Four dental interns collected the information and performed the dental examination. The calibration of the examiners started with (theoretical training, continued with clinical practice in a health center and was validated in the pilot test, with the diagnostic agreement of the principal investigator, which was of a moderate overall parameter (Fleiss' Kappa=0.60) 27.
The questionnaire collected sociodemographic data, socioeconomic level, oral hygiene, toxic and dietary habits. The dependent variable was severe caries and a case was defined as an adolescent with a detectable cavity in opaque or discolored enamel with visible dentin by the dental explorer test in at least one permanent molar, based on the combined codes 5 and 6 of the International Caries Classification and Management System criteria (ICCMS) 28. The identification of the first permanent teeth was based on the nomenclature of the International Dental Federation 29.
Socioeconomic level was determined based on the number of sleeping quarters, type of floor, access to technology such as computers, cell phones and internet services. The responses followed three ordinal categories, where scores of six to seven points were considered high socioeconomic level; middle class from four to five points and low class from one to three points.
Regarding smoking habits, the classification of cigarette consumption based on the World Health Organization citeria was used 30. The classification of smoking followed three ordinal categories: light smoker, consumption of less than 5 cigarettes per day; moderate smoker, 6 to 15 cigarettes per day; and severe smoker, more than 16 cigarettes per day.
For the evaluation of dietary habits, it was obtained from the analysis of the diet, which includes the type of diet, frequency and occasion of consumption 31. The scores for frequency and occasion of consumption were multiplied by the value of the type of food, the individual values for frequency-occasion were added together and a single value of consumption per frequency and a value of consumption per occasion were obtained; the cariogenic potential was the sum of these two values. The score obtained was placed in the ordinal values: low cariogenic risk from 1 to 33 points; moderate from 34 to 79 and high from 80 to 144.
The data collection and validation was done twice with the program EpiData V3.1T 32, in order to avoid typo mistakes. The program CIETmap 33, was used for the statistic analysis. An univariate analysis was done to obtain simple frequencies in the study variables. The prevalence ratio with its 95% confidence interval was calculated as a measure of association between the possible associated factors and the outcome variable.
Through multivariate analysis, a model of factors associated with severe caries of the first permanent molar was produced with the simultaneous analysis of the Mantel-Haenszel procedure 34. The initial saturated model included all the variables with statistical significance in the bivariate analysis, plus those variables added for plausibility criteria that served as adjustment. All variables were eliminated one by one, until only those with a significance level of <0.05 remained.
The project was approved by the Ethics Committee of the Health Jurisdiction 07 of the Secretariat of Health of Acapulco. The school authority obtained the permission of the parents or guardians by means of a circular letter and allowed data collection, in addition to requesting verbal informed consent from each participant. The adolescents responded to the questionnaire freely and voluntarily. The clinical examination was non invasive, without any health risk, and at the end the diagnosis found was shared with them.
RESULTS
A total of 173 adolescents between 12 and 15 years of age participated, with a mean of 14.02 years (SD 0.68). Table 1 shows the other characteristics in detail of the sociodemographic data of the study sample. As for the socioeconomic level, the 70% (n=122) of the adolescents were lower class, 28% (n=49) middle class and 2% (n=2) upper class.
Feature | n | % | |
---|---|---|---|
Gender | Females | 91 | 53 |
Males | 82 | 47 | |
Family member living | Both parents | 138 | 80% |
Mother | 27 | 16% | |
Other relative | 8 | 4% | |
Being an only child | Yes | 62 | 36% |
No | 111 | 64% | |
Schooling of parents or guardians | No estudies | 42 | 24% |
Basic level | 115 | 66% | |
Upper middle | 12 | 7% | |
Higher education | 4 | 3% | |
Total: | 173 | ||
About the oral hygiene data, the 52% (n=89) of the adolescents reported brushing their teeth three times a day, 21% (n=37) two times, 18% (n=31) one time and 9% (n=16) four or more times. The range of brushing frequency was 1 to 5 times with a mean of 2.5 (SD 0.96). The 68% (n=135) used toothpaste for cleaning and the rest only water. Regarding hygiene aids, 38% (n=66) used mouthwash, 7% (n=12) floss and the rest did not use any. In terms of health promotion instruction, 89% (n=154) had never received any oral health education and the rest had. The 52% (n=91) had not attended a dental appointment, 32% (n=55) between one and three years ago and 16% (n=27) in the last six months.
With regard to toxic habits, the 37% (n=65) of the adolescents consumed cigarettes. When classifying frequency, 65% (n=42/65) were light smokers, 28% (n=18/65) moderate smokers and 7% (n=5/65) severe smokers. Regarding alcohol consumption, 29% (n=51) consumed alcoholic beverages. When stratified, 53% (n=27/51) consumed 1 to 7 drinks per week, 29% (n=15/51) 8 to 15 and 18% (n=8/51) 16 or more. Data on cariogenic risk showed that 57% (n=98) had moderate risk dietary habits, 38% (n=66) low and 5% (n=9) high.
The 54% (n=94) of adolescents had severe caries in at least one permanent molar, and the rest had other uncounted or healthy categories. Table 2 shows that a total of 692 permanent first molars were examined, of which 396 were identified with severe caries. When distributed by jaw, the proportion of molars with mandibular caries was 80% (n=301/376), and the rest were from the upper jaw. As for the first permanent molar with the most severe caries was the lower right molar, with a proportion of 44% (n=167/376).
ICCMS criteria* | First permanent molars | |||||
---|---|---|---|---|---|---|
16 | 26 | 36 | 46 | n | % | |
Healthy | 96 | 57 | 73 | 90 | 316 | 46% |
Severe | 52 | 23 | 134 | 167 | 376 | 54% |
Total | 148 | 80 | 207 | 257 | 692 | 100% |
* The definition of severe caries was established based on codes 5 and 6 of the International Caries Classification and Management System
The bivariate analysis identified six factors associated with having severe permanent first molar caries among adolescents. The estimated unadjusted prevalence ratio and 95% confidence interval are shown in Table 3. The six relevant factors from the bivariate analysis, adjusted for the gender variable, were included in the initial saturated model of the multivariate analysis.
Variable Factor | Severe caries | No caries | PRna | CI 95% | p | |||
---|---|---|---|---|---|---|---|---|
n | (%) | n | (%) | |||||
Gender | Man Ref. | 38 | (22%) | 44 | (25%) | 0.76 | 0.57 - 1.01 | 0.055 |
Female | 56 | (32%) | 35 | (21%) | ||||
Age | 14-15 years Ref. | 61 | (35%) | 31 | (18%) | 1.65 | 1.21 - 2.25 | 0.001* |
12-13 years | 33 | (19%) | 48 | (28%) | ||||
School year | 2nd 3rd grade Ref. | 69 | (40%) | 47 | (27%) | 1.23 | 0.99 - 1.53 | 0.059 |
1st grade | 25 | (14%) | 32 | (19%) | ||||
Schooling of parents or guardians | No education and basic level Ref. | 88 | (51%) | 69 | (40%) | 1.07 | 0.97 - 1.18 | 0.170 |
Upper middle and high school level | 6 | (3%) | 10 | (6%) | ||||
Socio-economic level | Under Ref. | 71 | (41%) | 51 | (29%) | 1.17 | 0.95 - 1.42 | 0.123 |
Medium-high | 23 | (14%) | 28 | (16%) | ||||
Toothbrushing | ≥ 3 times a day Ref. | 39 | (22%) | 66 | (38%) | 0.49 | 0.32 - 0.64 | < 0.0001* |
< 3 times a day | 55 | (32%) | 13 | (8%) | ||||
Oral hygiene aids | Use Ref. | 19 | (11%) | 59 | (34%) | 0.27 | 0.17 - 0.41 | < 0.0001* |
Does not use | 75 | (43%) | 20 | (12%) | ||||
Health Promotion | If you have received Ref. | 8 | (5%) | 11 | (6%) | 0.61 | 0.25 - 1.44 | 0.262 |
Hast not received | 86 | (50%) | 68 | (39%) | ||||
Cigarette consumption | ≥ 6 times a day Ref. | 20 | (11%) | 3 | (2%) | 5.60 | 1.72 - 18.16 | 0.004* |
≤ 5 times a day | 74 | (43%) | 76 | (44%) | ||||
Alcohol consumption | Take Ref. | 36 | (21%) | 15 | (9%) | 2.01 | 1.19 - 3.40 | 0.008* |
It does not take | 58 | (33%) | 64 | (37%) | ||||
Cariogenic diet | Moderate-high Ref. | 66 | (38%) | 41 | (24%) | 1.35 | 1.05 - 1.73 | 0.017* |
Under | 28 | (16%) | 38 | (22%) | ||||
Total | 94 | (54%) | 79 | (46%) |
PRna = unadjusted prevalence ratio of the exposed population
CI 95% = confidence interval of 95%
p value of X2 test
The main strength of association was found in the variable compsumption of six or more cigarretes (PRa= 5.48), and the other was the use of hygiene aids (PRa= 0.41). Table 4 shows the adjusted estimate of the prevalence ratio of severe caries with its 95% confidence interval. The findings exclude distractor effect (counfounder) and the X2 test for heterogeneity was greater than 0.05 in all the associations of the final model, which excludes the existence of effect modification between the strata of the variables included.
Factors | PRa | CIa 95% | X 2 het |
---|---|---|---|
Use of oral hygiene aids | 0.41 | 0.34 - 0.78 | 1.08 |
Cigarette consumption ≥ 6 times a day | 5.48 | 2.01 - 17.87 | 1.17 |
PRa = adjusted prevalence ratio.
CIa 95% = adjusted confidence interval of 95%.
X2 het = chi-square of heterogeneity to evaluate effect modifiers.
*The initial saturated model included the following variables: age, toothbrushing, oral hygiene aids, cigarette consumption, alcohol consumption and cariogenic diet; they were adjusted for gender.
DISCUSSION
Two factors were associated with severe permanent first molar caries in adolescents. One factor was in the sense of risk, the consumption of six or more cigarettes a day. The other factor was protective, the use of oral hygiene aids.
This study, being of cross-sectional design, has limitations with respect to the temporality of the association between exposure factors and the effect. It is important to point out that there is a possible observation bias due to the moderate concordance obtained. The importance of carrying out an inter-examiner calibration based on the opinion of pediatric dentists is emphasized, aiming at a fine-tuned diagnostic system in future research.
A further important point was the operational definition of case, since only the category of severe caries was counted, leaving the initial and moderate stages as healthy cases, which underestimates the essence of the caries condition. Another issue was to carry out the study in the high school facilities, when ICCMS recommendations are to carry out the inspection in a comfortable cubicle with good light intensity, which allows to establish the categorization with the minimum margin of error.
Regarding the dental organs, the lower molars were the most affected, similar to what has been reported in several studies 13,15,16. This could be influenced by their chronology, since they erupt earlier than the upper ones. An additional reason is the morphology, because the cusps of the lower teeth are rounded, which allows the cusps of the upper teeth to occlude in front of them, therefore, there is a greater probability that food remains stagnant. Also, the force of gravity contributes to the fact that the food debris does not remain in the upper molars and due to the force of the tongue it is retained in the lower part.
It was found that the lower right first molar was the most frequently affected by severe caries. Valdes-Martínez et al., described that the left one is more affected in the cuban population 15. One difference is that they evaluated the situation with the Clune index, therefore, they describe the situation of the event by affected surface.
The prevalence of severe caries of 54% in the first permanent molar reported in this study was similar to that reported in the Palestinian and Venezuelan adolescent population 9,12. Other studies report high morbidity in more than three quarters of the adolescent population 11,16). One of the differences between our study and others was the operational definition, which encompassed the progression of caries to a certain category (severe). Other studies only evaluate the caries count, without the use of criteria that establish a categorization.
Cigarette smoking was found to be a risk factor contributing to the presence of severe caries of the first permanent molar. However, it is possible that the adolescents may have acquired the habit recently, so it is difficult to establish which came first, caries or smoking, thus presenting the phenomenon of reverse causality. Another fact is that in these questions there is a non-response bias, since adolescents deny the habit for fear that the information will be communicated to parents or guardians. There is probably an underestimation in the cases of this habit, so it is necessary to use other scales that have fixed parameters to establish an exact frequency of cigarette consumption.
Concerning the protection factor, the use of oral hygiene aids seems to reflect the attitude of adolescents to reinforce their cleanliness and to extend it to avoid infections. If this assumption is true, then the attitude precedes the appearance of caries. The use of hygiene aids enters a primary level of specific protection, together with frequency of dental visits, diet and fluoride topicalization 14,22,23.
Regarding gender, females were the most affected by caries, in agreement with other studies 9,16,17,19. This variable was included in the multivariate model for plausibility criteria; however, no association was found. Khorasani et al., mention that Iranian females have a higher occurrence of caries and Brito et al., report males in a study among the Brazilian population 10,14.
The results obtained show that severe caries was associated with various factors. Studies with greater methodological robustness, such as a cohort, are needed to clarify the factors involved in this population through follow-up. Dental organs with severe caries should be treated with damage-limiting procedures, and those in early or moderate stages with minimally invasive dentistry.
The simple selection study sample reflects a portion of adolescents from a public sector secondary school. The private sector secondary schools have different characteristics, therefore, they are not comparable. Nevertheless, the results of the study can be contrasted with a population of high school adolescents with similar characteristics.
In this study, consuming six or more cigarettes per day has about five times the risk of developing severe caries in the first permanent molar. Smoking is a deeply rooted habit in adolescents, therefore, it is necessary to address this problem with health education interventions. As for the protective factor, the use of hygiene aids has a 41% probability of avoiding caries infection, therefore, we suggest reinforcing primary strategies through health promotion. In spite of finding these associated factors, it will be necessary to carry out longitudinal research (cohort), with the advantage that in these studies the exposure is not present and establishes the temporality with the decrease of biases.