Caries experience in adolescents 13-14 years with and without erosive tooth wear: a case-control study

Introduction

Dental caries is the localized destruction of hard dental tissue by the acidic by-products of the bacterial fermentation of free sugars [1]. Despite being largely preventable, dental caries is the most common oral disease in the world, with increasing prevalence in many low and middle-income countries [2]. The oral environment is a modifier of caries risk that influences tooth development (e.g., fluoride exposure, risk of enamel defects), oral hygiene, topical fluoride exposure, carbohydrate exposure, microbiome exposure, and many other factors which also may modify the development of dental caries. On the other hand, the size, mineralization, and, even, morphology of pits and fissures are strongly determined by the genetic makeup or genome of the individual [3].

Tooth wear is the progressive loss of dental hard tissues through three processes. The first two are mechanical processes: abrasion (wear produced by interaction between teeth and other materials) and attrition (wear through tooth-tooth contact). These can contribute simultaneously to occlusal wear [4]. When the surface of the tooth is first attacked by acids, the resulting loss of structural integrity leaves a softened layer on the tooth’s surface, which renders it vulnerable to mechanical processes. These mechanical processes forces will remove the softened layer on dental hard tissues, causing substance loss [5].

Erosive tooth wear is defined as a chemical-mechanical process that results in the cumulative loss of hard dental tissue that is not caused by bacteria [5], with global prevalence varying widely between 0 and 97%, even within a specific country [6]. In ETW, dental erosion is the main etiological factor [7], wherein the chemical influence is an extrinsic acid, such as that introduced via diet and medication, and/or intrinsic acid, such as that occurring due to gastroesophageal reflux and vomiting [8]. For an acid attack to have a clinically-significant effect, exposure must be frequent and/or prolonged [9]. Biological factors, such as saliva, acquired film, tooth structure, and the position of a tooth in relation to soft tissue and the tongue are associated with the pathogeny of ETW [5]. Moreover, behavioral factors, including eating, drinking, and oral hygiene habits, are predisposing factors for ETW [10].

Epidemiological studies conducted in Mexico have reported a prevalence of ETW of between 32 and 64% in adolescents [11, 12], while the consumption of sweet carbonated drinks has been found to be associated with a higher prevalence of the condition [13, 14, 15].

Acidic drinks, such as sweet carbonated drinks, have been one of the most researched factors in the study of the condition subject to the present research. In-vitro studies have found that low pH beverages weaken the calcium and phosphate binding found in the mineral composition of enamel and dentin, leading to the release of these substances [16].

Adolescents consume high volumes of sweet carbonated drinks, corresponding to an average of almost one liter per day [13]. In Mexico, sweet carbonated drinks are consumed daily by 74% of the population, with an annual average 115 liters consumed per person [17]. It has been postulated that there may be common etiological factors between ETW and dental caries, such as the high or constant sweet carbonated drinks consumption, reduced salivary secretion, and unhealthy eating habits [18]. Few studies have reported on the relationship between the caries experience (CE) and ETW, indicating that adolescents with ETW present higher levels of caries [14, 18]; however, other studies have not found such an association [19, 20]. Considering the importance of the studies that report ETW in adolescents and their contradictory results, the objective proposed for this case-control study was to analyze the association between CE and ETW in a group of adolescents 13–14 years old from Mexico City.

MATERIALS AND METHOD

The present study was conducted on cases and controls identified from the findings of a previous cohort study [21]. The research protocol was submitted to the ethics committee of the Iztacala Faculty of Higher Studies of the National Autonomous University of Mexico (CE/FESI/032019/1287). The subjects’ parents or guardians provided their signed informed consent, while consent to participate in the study was also requested from the subjects themselves. The present study was carried out in adherence to the guidelines of the Strengthening the Reporting of Observational Studies (STROBE) statement.

RESULTS

Table 1 shows the comparison of the sociodemographic variables pertaining to the cases and controls, which revealed no significant differences among groups by age, sex, mother’s educational attainment, and visits to the dentist in the last 12 months (p $>$ 0.05). The mean BEWE score for the cases with distinctive defect was 4.77 $\pm$ 0.93 and 2.01 $\pm$ 0.54 for the cases with initial surface texture loss (p $<$ 0.001).

Table 2 presents the comparison of the risk indicators, wherein the cases with distinctive defect presented a lower level of weekly milk consumption (500 mL) (4.08 $\pm$ 3.37) than the cases with initial surface texture loss (4.98 $\pm$ 3.40) and the controls (5.19 $\pm$ 3.42) (p = 0.043). The weekly intake of sweet carbonated drink (500 mL) was 3.22 $\pm$ 4.18 for the cases with distinctive defect, 2.90 $\pm$ 3.08 for the cases with initial loss and 1.98 $\pm$ 1.96 for the control group, (p = 0.083).

Table 3 presents the comparison of CE, dental hygiene, and salivary parameters. With regard to CE, the cases with distinctive defect (6.96 $\pm$ 4.61) and initial surface texture loss (6.36 $\pm$ 4.02) presented a higher DMFT index score than the controls (5.43 $\pm$ 4.14) (p = 0.040), while no significant differences were observed between groups for both dental hygiene and salivary parameters (p $>$ 0.05).

The final multinomial logistic regression model (Table 4) showed that, for each tooth with CE, adolescents were 9% more likely to become a case with a distinctive defect than the controls (OR = 1.09 (95% CI: 1.01–1.17); p = 0.020). For each portion of intake of sweet carbonated drink, a 16% increase was observed (OR = 1.16 (95% CI: 1.03–1.31); p = 0.012). Finally, the adolescents who reported frequent vomiting were 3.19 times more likely to be a case with a distinctive defect (OR = 3.19 (95% CI: 1.02–10.01); p = 0.047).

DISCUSSION

The findings of the present study show an association between CE and the presence of ETW. The sweet carbonated drink consumption was shown to be associated, in general, with the presence of ETW, in terms of both initial surface texture loss and more severe loss, while frequent vomiting was shown to be associated with severe ETW in the study sample.

The present study is the first to be conducted on cases and controls for ETW in the Mexican population, in which the prevalence of caries is among the highest in the world for adolescents [26], the group which presents the highest levels of one of the most-frequently studied factors associated ETW, sweet carbonated drink consumption [17]. The cases were identified from a cohort study previously carried out on an open population (not volunteers from dental clinics or hospitals) and with controls selected from the same population, which helps with the comparability between groups [21]. A group of cases with initial wear was selected as a comparison group, in which advanced erosive wear (a distinctive defect) had not been detected at the time of the study.

Among the weaknesses of the study is the possible memory bias regarding beverage and citrus fruit consumption, while another is that the information on gastroesophageal reflux and frequent vomiting was obtained from a self-reported questionnaire, as it was not possible to include a specialist diagnosis.

Like other reports [14, 18, 27], the present study found that the presence of teeth with CE is associated with ETW. However, there are studies that have not found such an association [19, 20]. Although dental caries and ETW share etiological factors [18], the differences among reports may be due to the different conditions in each country in terms of habits, education, and access to health services, among others.

On the other hand, the present study found an association between the sweet carbonated drink consumption and ETW, with the former reported as a factor associated with ETW in both the Mexican population and other parts of the world [11]. A recently published meta-analysis [28], conducted on 52 articles, found that a considerable variety of drinks, foods, and dietary habits were associated with the presence of ETW; however, carbonated drinks were the most consistent indicator of risk.

Finally, the present study found an association between frequent vomiting and ETW, which concurs with the results of a meta-analysis that showed that patients with eating disorders and self-induced vomiting have a high probability of presenting ETW [29]. The gastric juice that rises up via the esophagus and comes into contact with the structures of the oral cavity, including the teeth, can cause ETW, as the pH of the juice is even more acidic than that of drinks and foods with erosive potential [30]. Furthermore, it has been found that adolescents who present frequent vomiting also present a high consumption of acidic foods and drinks, such as carbonated drinks [31].

It has been shown that in adolescents, the teeth most affected by erosive wear are the lower first molars and upper anterior teeth [21]. ETW in lower molars are mainly located on the occlusal surface, while in upper anterior teeth these are situated on the palatal surface [32]. This could be because these permanent teeth erupt first and are therefore exposed to etiological factors for a longer time.

On the other hand, gastric juice that comes into contact with hard dental tissues from frequent vomiting or gastroesophageal disease can result in loss of enamel and dentin from the palatal surfaces of the upper incisors [30]. In the case of lower molars, the loss of tissue on their occlusal surface may be explained by the interaction of attrition and abrasive diets after acid challenges [4].

Preventive management of ETW should focus to reduce or stop the progression of the lesions. Information on clinical presentation and etiological factors should be analyzed carefully [33]. A record should be made of the foods and drinks that they habitually consume, including specific eating and drinking habits. The dentist may play an important role in detecting relevant disorders, such as frequent vomiting and gastroesophageal reflux [8]. Whenever possible, the clinical examination should be accompanied by measurement of the salivary flow rate [34].

When intrinsic acid sources are suspected to be the main causal factor, then referral to a specialist or a general practitioner is advised [33]. If the food diary suggests that extrinsic erosive sources are a significant causal factor, must recommend reducing the frequency of consumption of the identified erosive foods and beverages [34]. Products (e.g., toothpastes or mouth rinses) containing stannous fluoride have the potential for slowing the progression of ETW [35].

Future studies on ETW and its relationship with intrinsic sources of acid should include a diagnosis made by a specialist and adhere to a longitudinal design that enables causality to be established.

CONCLUSIONS

The preventive management of both ETW and dental caries should aim to reduce exposure to foods and beverages with high acid and sugar content, such as sweet carbonated drinks. ETW can be an indicator of the presence of gastric acid, which, although it may be less common than extrinsic sources of acids (food, beverages, and medications), may suggest the need for a more in-depth study to determine the presence of a condition that may be exposing teeth to said acid.

FUNDING

This research received no external funding.

CONFLICT OF INTEREST

The authors declare no conflict of interest.