The development of carious lesions around brackets and bands used in fixed orthodontics is a common side effect of orthodontic treatment. This is likely due to the increased biofilm accumulation around the fixed appliances. Initial carious lesions can become evident in a short period, with some developing within a month of treatment initiation.1
The reported prevalence and incidence of caries initial carious lesions varies considerably across studies from 27% to 97%. A recent systematic review and meta-analysis evaluated the prevalence and incidence rates of initial carious lesions associated with orthodontic treatment.1
The Review
A total of 21 studies were included in the systematic review, with all except two of those included in the meta-analysis. Studies included were characterized as randomized and non-randomized clinical trials of interventions, cohort studies, and cross-sectional studies.1
Studies ranged from 1990 through May of 2023, with inclusion criteria that the study reported the prevalence or incidence of initial carious lesions during or after orthodontic treatment with fixed appliances.1
The methods described in the studies selected to identify initial carious lesions included inspection/visual/clinical and/or dental radiographs. In two studies, light-induced fluorescence was used.1
Sample sizes ranged from 20 to 202 participants. Seven studies only included adolescents.1
The Results
The result indicated that, on average, more than half the participants developed initial carious lesions during or after orthodontic treatment, with an average of participants developing two new lesions and one-sixth of the surfaces becoming affected.1
The contribution of age to the higher prevalence of lesions was inconsistent. A higher prevalence of lesions was reported for participants ages 11 to 15 (62.8%) when compared with those aged 16 to 24 (47.7%). However, the meta-analysis did not find a statistically significant association between age and number of initial carious lesions.1
The duration of orthodontic treatment was associated with an increase in initial carious lesions. A higher prevalence has been described for participants over 20 years of age as the length of orthodontic treatment may increase.1
Multiple etiologies were identified in the onset and progression of initial carious lesions associated with fixed orthodontic appliances. The presence of bacterial biofilm increased fivefold during orthodontic treatment. This was attributed to the difficulty in maintaining good oral hygiene. However, the biofilm present was not directly proportionate to caries risk. The risk only increased in the presence of cariogenic bacteria.1
The lateral incisors and maxillary canines were the most common sites for developing initial carious lesions. Other areas of increased incidence include the maxillary and mandibular premolars and first molars. This was attributed to a couple of factors: 1) the small area of tooth surface between the bracket and gingiva enhanced biofilm retention, and 2) different salivary exposure in affected versus unaffected areas.1
Only a few studies in the review evaluated homecare as a risk factor for developing initial carious lesions. All studies assessing homecare determined that increased frequency of daily toothbrushing and/or good oral hygiene was associated with a decreased incidence of initial carious lesions.1
Conclusion
The authors stated, “The prevalence and incidence rates of ICLs [initial carious lesions] in subjects undergoing orthodontic treatment are quite high and raise some concerns in terms of risk assessment of orthodontic treatment. ICLs represent an alarming challenge for both patients and professionals. Effective caries prevention strategies during treatment need to be considered and implemented where appropriate.”1
Prevention strategies proposed include professional fluoride application and biofilm management strategies. Professionally applied fluoride varnish every two to three months significantly reduced the development of initial carious lesions, while fluoride rinses only reduced the incidence slightly. Prescription fluoride toothpaste (5,000 ppm) or fluoride-releasing bonding or sealants also successfully reduced the incidence of initial carious lesions.1
Since patient compliance is a large part of success, the only mitigating factor dental professionals have control over is the application of fluoride treatments. Therefore, along with biofilm management strategies, professional fluoride products should be an integral part of orthodontic treatment.1
Fixed orthodontic appliances can raise the risk of biofilm accumulation and tooth decay. This makes it essential to account for all other risk factors to accurately gauge the impact of orthodontic treatment on the formation of initial carious lesions.1
Future studies on initial carious lesion incidence should carefully screen patients for caries risk factors before and during fixed orthodontic treatment, utilizing standardized assessment tools.1
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Reference
1. Salerno, C., Grazia Cagetti, M., Cirio, S., et al. Distribution of Initial Caries Lesions in Relation to Fixed Orthodontic Therapy. A Systematic Review and Meta-Analysis. Eur J Orthod. 2024; 46(2): cjae008. https://pmc.ncbi.nlm.nih.gov/articles/PMC10883713/
