14 July 2020

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Post-orthodontic white-spot lesions: are resin infiltration and microabrasion effective treatment?

Co-authors: A. Comba, F. Florenzano

Lorenzo Breschi

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The development of white spot lesions (WSLs) is one of the most common adverse effects of orthodontic treatment. During the orthodontic treatment the reduction of adequate oral hygiene due to the fixed appliances for a long period leads to the formation of WSLs. At least 50% of patients with fixed appliances develope one or more WSLs by the end of treatment. Therefore, during the orthodontic treatment enamel demineralization remains an issue, in particular because the progression of white spot lesions could affect the final esthetic outcome of the treatment. Nowadays, two different minimally invasive treatments are available on the market: resin infiltration and microabrasion. However, there are few clinical researches analyzing the pros and cons of the two treatment options.

The group of Xi Gu & al., from the University of Sichuan in Chengdu, China conducted a clinical study in order to evaluate differences in infiltration and microabrasion protocols outcomes. On one side, Resin infiltration, recently developed, aims to arrest carious lesions progression through the penetration of low-viscosity resin into the enamel depth. The resin creates a barrier inside the enamel substrate that avoid the penetration of acids and the arrests the progression of the demineralization. On the other side, Microabrasion could improve the appearance of teeth by eliminating the outer defective layer of the enamel. The protocol consists on the application of 6,6% hydrochloric acid associated with superficial enamel removal with 20- to 160- µm silicon carbide. At present, the long-term esthetic improvement of resin infiltration or microabrasion for in the treatment of WSLs is still unknown.  

Materials and Methods
 To evaluate the aesthetic results of the two treatment, the Chinese research group conducted a split mouth clinical study. The authors selected a total of 20 patients with 128 teeth presenting post-orthodontic WSLs. They employed a  simple randomized, split-mouth, positive controlled design to allocate patients to the resin infiltration or microabrasion group. Inclusion criteria were patients from 12 to 19 years old who had finished fixed orthodontic treatment with debonding more than 3 months before the inclusion in the study and with the presence of WSLs on the anterior teeth induced by brackets. The exclusion criteria imposed by Xi Gu & al. were the presence of cavitated lesions and enamel defects, such as enamel hypoplasia, fluorosis, and tetracycline staining on anterior teeth. The authors calculated the lesion area ratio (R value) between the area of a WSL and the labial surface of the corresponding tooth based on standardized clinical photographs. The color change (DE) of each tooth was measured with a Crystaleye spectrophotometer (Olympus, Tokyo, Japan). Every measurement was taken before treatment (T0) and at 1 week (T1), 6 months (T6), and 12 months (T12).  

Results
 The authors selected a total of 16 patients with 108 teeth, 54 for each group. The analysis of the obtained data showed a significant decrease in the R value and DE between T1 and T0 (P < .0001). In the infiltration group, the R value and DE had no significant changes over time from T1 to T12. In the microabrasion group, the R value and DE decreased significantly from T1 to T6. The R value of resin infiltration was lower when compared with microabrasion at every recall point (P< .001). The DE had no significant differences between the two groups at any timepoint.  

Conclusions
 Considering the results obtained by Xi Gu & al., it can be concluded that resin infiltration and microabrasion are to effective protocols to improve the esthetic appearance of WSLs and showed good results after 12 months follow-up. However, Resin infiltration showed a better esthetic improvement effect when compared with microabrasion after 12 months.                   

 For additional information: Esthetic improvements of postorthodontic white-spot lesions treated with resin infiltration and microabrasion: A split-mouth, randomized clinical trial.