|Year : 2021 | Volume
| Issue : 2 | Page : 113-119
Effectiveness of the use of xylitol chewing gum in prevention of dental caries: A systematic review
Kelly Rodrigues Mota1, Joăo Vitor Farias da Silva2, Cristine D’Almeida Borges3, Priscylla Gonçalves Correia Leite de Marcelos1, Pamella Recco Alvares4, Valdeci Elias dos Santos Júnior1
1 Department of Paediatric Dentistry, Federal University of Alagoas, Maceió, Brazil
2 Department of Medicine, Federal University of Sergipe, São Cristóvão, Brazil
3 Department of Periodontics, Federal University of Alagoas, Maceió, Brazil
4 Department of Pathology, University of Pernambuco, Recife, Brazil
|Date of Submission||09-Sep-2020|
|Date of Decision||06-Dec-2020|
|Date of Acceptance||02-Apr-2021|
|Date of Web Publication||29-Jul-2021|
Source of Support: None, Conflict of Interest: None
| Abstract|| |
This systematic review of the literature assessed the effectiveness of using chewing gum containing only xylitol compared to prevention strategies or placebo in reducing the incidence of carious lesions in children using data obtained from randomized controlled trials. Electronic search was carried out in PubMed MEDLINE, Latin American and Caribbean Literature on the Health Science, Web of Science, Scopus, Science Direct, and Scientific Electronic Library Online through the period between 2000 and 2020. Included clinical studies were done in children when the xylitol was dispensed in gum and the preventive effect of xylitol on tooth decay was compared to other preventive strategies or control groups. The studies were evaluated for their quality to obtain the level of evidence. The preventive fraction of each study was extracted. Two hundred studies were found. After analyzing the inclusion and removal of duplicates, only five studies were analyzed for the quality of evidence. With the analysis through the Grading of Recommendations Assessment, Development, and Evaluation system, it was possible to verify the very low level of scientific evidence on the effectiveness of gums containing only xylitol for the prevention of caries in children. The preventive fraction obtained varied between − 0.31 and 0.57 depending on the compared prevention strategy. The conflicting results, limitations, and inconsistencies of the studies allow us to establish that there is insufficient evidence to support the use of gums containing only xylitol for the prevention of caries in children. Other properly designed clinical trials need to be carried out.
Keywords: Children, dental caries, evidence based, preventive, xylitol
|How to cite this article:|
Mota KR, da Silva JV, Borges CD, Leite de Marcelos PG, Alvares PR, Santos Júnior VE. Effectiveness of the use of xylitol chewing gum in prevention of dental caries: A systematic review. J Indian Soc Pedod Prev Dent 2021;39:113-9
|How to cite this URL:|
Mota KR, da Silva JV, Borges CD, Leite de Marcelos PG, Alvares PR, Santos Júnior VE. Effectiveness of the use of xylitol chewing gum in prevention of dental caries: A systematic review. J Indian Soc Pedod Prev Dent [serial online] 2021 [cited 2021 Oct 24];39:113-9. Available from: https://www.jisppd.com/text.asp?2021/39/2/113/322504
| Introduction|| |
Caries has a complex etiology of a multifactorial nature and dependent biofilm – sucrose, being considered a chronic-cumulative disease, shaped by social and behavioral factors., Global reports demonstrate that the reduction in caries prevalence has been overestimated., The prevention of caries around the world is based on the reduction of sucrose consumption, as it understands that this substance causes major biochemical and physiological changes during the formation process of oral biofilm, increasing the virulence of Streptococcus mutans and favoring a greater accumulation of these microorganisms, a condition called dysbiosis.,
However, this form of caries prevention control encounters obstacles in strong dietary-cultural and economic factors, especially in poor countries like Brazil, which has limited its contribution as scientific evidence. Thus, a substitution of sucrose for sweeteners has been recommended by important institutions such as the US Food and Drug Administration and the American Pediatric Dentistry Association. In this context, xylitol, an alcohol sugar (polyol), appears as an alternative to the use of sucrose with the potential to cause disturbances in the metabolism of cariogenic bacteria, reducing its acid production capacity.,
However, the reduction in the incidence of caries caused by the consumption of xylitol is not yet clear. There is a scientific gap regarding its dose–response, frequency of use, and its adequate delivery vehicle, such as chewing gum. In fact, this systematic review of the literature assessed the effectiveness of using chewing gum containing only xylitol compared to prevention strategies or placebo in reducing the incidence of carious lesions in children using data obtained from randomized controlled trials. This review differs from the others related to the topic in that it exclusively analyzes gums that contain only xylitol, therefore without the confusion factor generated by the addition of other polyols that may generate bias.
| Methods|| |
A research protocol was developed and registered on the Prospero system (CRD42020197945) that guided all forms of data search and evaluation. In June 2020, eligible studies were identified through electronic search on PubMed, MEDLINE, Latin American and Caribbean Literature on the Health Science, Web of Science, Scopus, Science Direct, and Scientific Electronic Library Online. The search strategy was developed to answer the following patient, intervention, comparison, outcome (PICO) question: the use of chewing gums containing only xylitol compared to prevention strategies or effective placebo to prevent caries in children?
The detailed search strategy on each platform can be requested from the authors. However, keywords (MeSH term and/or word text) and Boolean operators AND and/or OR were used to ensure a broad search for further analysis of the inclusion criteria. Words such as “Child,” “Children,” “Caries,” and “Tooth decay” were appropriately combined and modified on each platform [Table 1]. The search was carried out independently by two calibrated researchers, and the disagreements were resolved through consensus or through a third reviewer, “Dental caries,” “Prevention,” “Xylitol.”
Inclusion and exclusion criteria
We considered all controlled trials published between 2000 and 2020, written in English, Portuguese, or Spanish, as eligible for inclusion if they examined PICO question. We excluded articles that addressed only the microbiological effect of using xylitol gum; use of xylitol by means of vehicles other than chewing gum (tablets, toothpaste, or candies); and use of xylitol in conjunction with another type of intervention. Initially, articles were categorized into three groups: excluded, maintained, and a group of articles to be analyzed by consensus. Duplicate articles were excluded, and selected articles were read and evaluated in full for final inclusion in the results section. Discrepancies regarding the inclusion of articles were resolved through consensus.
With the full articles, information such as authors, year, categorization of the sample, interventions, frequency of consumption and xylitol concentration, previous analysis of the risk of caries, time between evaluations, caries diagnosis criteria (caries index), increment of caries, and main conclusions was collected. For the analysis of caries increment, only the clinical diagnosis was considered. Radiographic diagnosis, when it existed, was not part of this analysis. The caries preventive fraction was estimated by analyzing the increase in caries in the experimental group (chewing gum containing only xylitol) and in the control group (caries preventive method or placebo group). The formula used to obtain the calculation of the preventive fraction was PF = (Xc – Xe)/Xc, where “X” is the mean increment of caries in each group.
Analysis of the quality of the data took place using the tool for the analysis of the risk of bias elaborated by Cochrane that assesses the risk of bias through six domains: selection bias, performance bias, detection bias, follow-up bias, bias reporting, and other types of bias. In addition, the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) system was used to grade the quality of evidence and the strength of health recommendations.
Only the following outcome was analyzed: prevention of caries. The data were presented in tables, flowcharts, and graphs. The calculation of the preventive fraction was performed for the extrapolation of data. The software RevMan 5.4 (The Nordic Cochrane Center, The Cochrane Collaboration, Copenhagen, Denmark) was used to analyze the results.
| Results|| |
Two hundred articles were found in the potentially eligible databases. Following the analysis of titles and abstracts, 47 duplicated articles were identified, which were promptly excluded. Of the 153 previously eligible articles, 120 did not address the specific objective of this systematic review, thus leaving 35 manuscripts that were analyzed in their entirety. After such an eligibility analysis, 30 studies were excluded for the following reasons: studies in which chewing gum is associated with other substances (4); study on the microbiological effect of xylitol (23); effect of xylitol on pH (2); and one study was excluded because it was an analysis of a previously published main study (1). Therefore, only five studies were included for qualitative analysis and synthesis [Figure 1].
|Figure 1: Quality of reporting in systematic review flowchart of select articles|
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General characteristics of selected clinical trials
All included studies were conducted in Northern European countries. Four of the five studies were carried out at the beginning of this century between 2000 and 2003. Together, the studies analyzed 2.854 children aged 3–14 years. This age variability meant that deciduous and permanent teeth were added to the analysis, which may have generated selection and heterogeneity biases between studies. Corroborating with this situation, the dose of xylitol and the frequency of its consumption also varied between studies. Furthermore, no study has broadly assessed the risk of individual caries in children before including them in each study. As for the outcome assessments, the moments of each study were different. Finally, there was no consensus regarding the diagnosis of caries (including or not incipient lesions) and the adopted caries index (decay-missing-filled and decayed, missing, and filled permanent teeth or surfaces) [Table 2].
The five studies were evaluated according to the six domains of Cochrane to assess the risk of bias: selection bias, performance bias, detection bias, follow-up bias, bias reporting, and other types of bias. [Figure 2] shows a summary of these domains per the study, classified as high, unclear, and low risk of bias. The most critical domains were regarding randomization, allocation, and incomplete description of outcomes. Three studies,, were randomized by school, while the other two, were unclear or did not say whether they performed this procedure. School randomization does not provide the same probabilistic chances of receiving different interventions. In addition, this procedure compromises the confidentiality of research allocation. The method of allocating children was not reported in any of the studies.,,,, Important biases were found in the description of the blinding of the participants/patients in three of the five included studies, as well as risk of bias in four of the five studies for blinding the outcome evaluator. The sample losses in all studies were quite large, no study included such losses in the final analysis (analysis by intention to treat), and one study did not report the DMF in the initial moment so that it was not possible to extract the caries increase or the fraction preventive. One study did not fully report the variables of interest, and another did not present a clear analysis of the data. All studies analyzed did not assess the individual risk of caries, assuming a potential risk of confusion bias. All studies analyzed did not assess the individual risk of caries, assuming a potential risk of confusion bias. The detailed description of this analysis is shown in [Figure 2] with descriptive support in [Table 2].
|Figure 2: Risk of bias summary: Review authors' judgments about each risk of bias item for each included study|
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The studies were analyzed using the GRADE system to identify limitations, inconsistencies, indirect evidence, inaccuracies, and any other relevant considerations. With such analysis, it is possible to classify the quality of evidence as high, moderate, low, and very low. The quality of the grouped studies was then analyzed, checking for the existence of serious limitations and inconsistencies, as reported in [Table 3]. With this, it was possible to identify that the quality of the available evidence regarding the analyzed outcome is considered very low.
|Table 3: Quality analysis by grading of recommendations assessment, development, and evaluation|
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Study outcomes (caries prevention)
Studies report divergent conclusions regarding the effectiveness of xylitol gum in preventing caries in children. The increase in caries was analyzed in four of the five studies that had such data available. The prevented fraction of the gum containing only xylitol in comparison with other interventions or control is described in [Table 2]. The dose was also possible to relate xylitol in chewing gum to the preventive fraction when compared to other prevention or control strategies [Figure 3].
|Figure 3: Relationship between xylitol dose and prevented fraction compared with other preventive strategies or control at finish assessment on each randomized controlled trial|
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| Discussion|| |
The heterogeneity of the randomized clinical trial methods included in this systematic review highlights the need for a cautious interpretation of their individual data. There is variability in results regarding the effectiveness of gum containing only xylitol for preventing caries in children, which is partly explained by the high risk of bias found in all studies. Even with a promising mechanism of action,,, xylitol in chewing gums has a very low level of evidence for reducing caries levels, and its recommendation for the purpose of caries prevention should be reviewed.
Most studies try to support the idea that xylitol can be a prevention strategy for caries by having a microbiologist's view of the disease., However, because it is complex in nature, it is not plausible to implement antimicrobial materials per se for the practice of prevention not based on behavior change through the principle of health education., The number of salivary S. mutans is not a proximal parameter for analyzing the risk of caries alone. In this context, the study conducted by Anttonen et al. shows an analysis of the survival of decay-free primary teeth after exposure to xylitol or sucrose. In assessing the outcome (prevention of caries), the authors divide the analysis segments according to the S. mutans count into the intervention groups, with the intention of establishing a prediction relationship between these variables. However, these microbial tests have limited applicability for predicting caries. In addition, this attitude does not take into account the current stage of knowledge about the etiology of caries in relation to the complexity of the biofilm involved.,
Salivary flow can be stimulated by chewing and the sweet taste of xylitol which is present in chewing gum. This characteristic increases the buffering capacity of saliva and consequently can help prevent tooth decay. However, according to Machiulskiene et al., the mechanical stimulus to chew, by itself, may be more important to prevent tooth decay than the use of xylitol. Another hypothesis shows a possible influence of xylitol in the de-remineralization process. For this mechanism, the hydrophilic molecule of xylitol is capable of forming complexes with calcium in saliva, which can stabilize the calcium phosphate systems present in the oral environment. Calcium saturation in saliva promotes a tendency to remineralize dental tissues by depositing this ion and controls the dissolution of calcified tissues, such as teeth. However, the high variability of xylitol doses present in the studies,,,, and the high frequency required to obtain a minimal preventive effect mean that this strategy has been discouraged in new well-conducted randomized clinical trials that could be included in this systematic review.
Considering that childhood is a stage subject to behavioral changes and skills acquisition, no study,,,, has extensively analyzed children's individual caries risk for inclusion in the sample. Neither has the analysis of such risk been used dynamically in subsequent assessments. Caries is a cumulative disease throughout life; thus, lesions on deciduous teeth, even when exfoliated, must be count in the final results to determinate on global increment caries experience. None of the five studies,,,, reported for sure how they treated caries data for exfoliated primary teeth. With a potential risk of bias, none of the studies report the treatment of these records in their analyses. Nevertheless, the diagnostic criteria and caries indexes adopted to obtain the outcome measures make such data heterogeneous and inaccurate since the caries lesions go beyond the understanding of a cavity.
The findings of this systematic review allow stating that the data available by means of clinical trials are insufficient to indicate chewing gum containing xylitol as a strategy to prevent caries in children. These results are antagonistic to the meta-analysis performed by Deshpande and Jadad. This is because the authors included in their analysis studies with different designs, different xylitol delivery vehicles, and association of xylitol with other polyols. Such generalizations assume biases that a more specific guiding question sought to define. Thus, new studies properly designed need to be carried out to fill this scientific gap; however, preventive strategies based on chemical substances not associated with behavior management, including diet and hygiene, will tend to fail due to the multifactorial nature of the caries disease.
| Conclusions|| |
The conflicting results, limitations, and inconsistencies of the studies allow us to establish that there is insufficient evidence to support the use of gums containing only xylitol for the prevention of caries in children. There is a need for rigorously conducted studies to establish doses and possible effects on incipient caries.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3]
[Table 1], [Table 2], [Table 3]