Table 2.

Findings of included articles

Author	Diagnostic method of white spot lesion/study selection criteria	Outcomes	Significant correlations	Interpretation	Limitations	Key findings related to the research question
1. Azeem M and Hamid W (2017)[9]	Quantitative light-induced fluorescence was taken before and directly after clear aligner treatment	1. PRIMARY OUTCOME To assess the incidence of WSL formation in the subjects treated with clear aligner therapy	1. The overall incidence of new WSLs was 2.85% for all the assessed teeth	A total of 1.28% of the patients were affected by at least one new WSL	limited sample size, lack of blinding, lack of control group, and lack of comparison with fixed appliances.	Orthodontic treatment with clear aligner therapy showed a low incidence of newly developed WSLs
2. Alshatti et al.(2017)[13]	Visual evaluation of pre and post-treatment digital photographs, measurement of lesion done only on the maxillary lateral incisor	1. PRIMARY OUTCOME To measure and compare the incidence of WSLs in the three different groups using a modified version of the “Gorelick White Spot Lesion Index” 2. SECONDARY OUTCOMES a. To measure and compare the severity of WSLs using ImageJ software b. To evaluate correlation between Gingival, Plaque, and Bleeding Indices and WSLs.	1. For Group 1, 2 and 3, 29%, 44%, 47.4% of the patients developed WSL at T2, respectively. For Group 1, 2, 3, the percentage of patients who change from lesion-free at T0 to having lesion (s) at T2 were 41.18%, 63.64%, and 52.94%, respectively. 2. Surface Area (SA) change from T0 to T2 in Group 1, 2 and 3 was of 0.066±0.092, 0.110±0.095, and 0.093±0.112 respectively with P<0.05. The P value was 0.2763 (> 0.05) for differences in surface area (size) of WSLs among the groups. 3. Lesion size change and the changes in gingival architecture, appearance of plaque, and bleeding pattern were 0.087, 0.167 and 0.0032 with Pvalue of 0.51, 0.21 and 0.98, respectively (all P>0.05).	1. No significant difference in the incidence of WSL between the types of appliances. 2. WSL size the change were all significant within each group but not significant among the groups. 3. Despite the increase in the gingival index, plaque index, and bleeding on probing index status, there was no correlation between them and the change in the dimension of WSLs.	Lack of a standardized protocol of image taking technique.	There was no difference in the incidence and the severity of white spot lesions among clear aligners, self-ligating brackets, and conventional brackets.
3. Buschang et al. (2019)[14]	Visual evaluation of pre- and post- treatment photographs by two investigators	1. PRIMARY OUTCOME To Evaluate the incidence of WSLs among CA and FA groups. 2. SECONDARY OUTCOMES	1. 1.2% CA and 25.7% FA developed WSLs (P<0.001) 2. Total number of WSLs that developed=3 in CA and 174 in FA (P<0.001)	1. Patients treated with aligners showed less incidence and risk of developing WSLs than patients treated with traditional braces. 2. Patients with poor pre-treatment OH developed more WSLs than were those with good OH.	1. Less sensitivity of diagnosing WSLs. 2. Patient withdrawl- 85% of the aligner cases and 48% of the fixed cases	Patients treated with aligners showed less incidence and risk of developing WSLs than patients treated with traditional braces.
		a. To Evaluate Risk factors for the development of WSLs. b. To Evaluate the Incidence of WSLs between both arches and all teeth.	3. Fair (3.4 times) or poor (6.5 times) pre-treatment OH, worsening of OH during treatment (1.6 times more), pre-existing WSLs [8.5 times more likely (P<0.001)], and longer treatment duration (1.6 times more for>2 years) significantly (P<0.05) increased the risk of developing WSLs in FA group. 4. The incidence of WSLs for the maxillary canines, lateral incisors, central incisors, was 7.3%, 6%, 2.9%, respectively. The incidence of WSLs for mandibular canines, laterals incisors, and central incisors, was 7.1%, 2.6%, 2.2% respectively	3. The low incidence of WSLs in patients with removable aligners can be attributed to the shorter treatment durations and better hygiene. 4. Greater incidence of WSLs for the maxillary than for the mandibular teeth, and it was greater for the canines than for the incisors.	3. The pre-treatment differences in OH could have been counteracted by the pre-treatment differences in fluorosis. 4. Group differences in pre-treatment complexity and treatment results were not controlled
4. Karad et al. (2019)[15]	Not applicable	Not applicable	Not applicable	1. Expert opinion- If oral hygiene is adequately maintained, which is possible in the case of aligners, WSL formation can be reduced. 2. Expert opinion- CaSP has been found to be an effective remineralizing agent compared with other agents in a majority of studies; however, these studies were conducted in vitro.	1. Narrative review with no level of evidence given for the included studies	Orthodontic treatment with CA was associated with a low incidence of newly developed WSLs with a major role in patient education, motivation, and compliance in maintaining oral hygiene.
5. Albhaisi et al (2020)[16]	Quantitative light-induced fluorescence- QLF images were judged visually for signs of decalcificatio. The QLF images were analyzed using customized software (QA2 version 1.18)	1. PRIMARY OUTCOME To evaluate the mean amount of fluorescence loss (⧍F%) reflecting the mineral loss in percent.	1. Significant difference between the mean amount of fluorescence loss of 0.4% for the CA group (P=0.283) and 1.2% for the FA group (P=0.013). 2. Significant difference in the number of newly developed lesions between the two groups (P=0.039), the incidence in FA group=8.25 and in CA group=6.21	1. Increase in tooth demineralization was seen in both groups, but significantly more in the FA group. 2. More incidence of WSLs was seen in patients with FA than CA.	1. No long-term evaluation of enamel demineralization due to the short duration of study. 2. No sex-based comparison as most participants were female.	More incidence of WSLs was seen in FA (8.25) when compared with CA (6.21)
		2. SECONDARY OUTCOMES a. To Evaluate the Number of newly developed lesions b. the deepest point in the lesion (⧍Max), c. Lesion area (pixels) d. plaque surface area (⧍R30)	3. The lesion area was significantly higher (P<0.001) in the CA group at T1. 4. FA group exhibited significantly more plaque at T1 than T0 (P<0.001) and more than the CA group at T1 (P<0.001).	3. Larger lesion areas with less mineral loss were found in the CA group than in the FA group. 4. More plaque deposition in the FA group at T1 than T0.