Quantitative light-induced fluorescence assessment of white spots following semi-rapid maxillary expansion.

Background: This study aimed to investigate if the semi-rapid maxillary expansion (SRME) can cause white spot lesion (WSL) formation using quantitative light-induced fluorescence digital (QLF-D).

Methods: The SRME group comprised 15 patients (9 girls, 6 boys; 13.5 ± 1 years) who had transverse maxillary deficiency and underwent expansion with full-coverage expanders. The screw of the expanders in the SRME group was activated twice a day for the first week. After decementation at the end of the first week, the screw activation protocol was changed to 3 turns/ week. In the SRME group, the QLF-D images were captured before starting treatment and 3.18 ± 0.32 months later when the expansion treatment was completed. The control group consisted of 15 subjects (8 girls, 7 boys; mean age 14.2 ± 1.9 years) who never had orthodontic treatment. The images of the control group were obtained with 3 months interval. The images were analyzed in terms of demineralization using analysis software.

Results: The left central incisor was the only tooth that was affected by WSL formation in the SRME group after expansion. The left central incisor tooth's fluorescence levels were decreased and the lesion area increased significantly (p < 0.05). No significant mineralization changes occurred in the control group (p > 0.05).

Conclusions: SRME resulted in WSL formation in the left central incisor, while other teeth were not affected by demineralization. Although providing adequate oral hygiene is easier during SRME due to the removable appliance, the orthodontist should still be aware that it may cause demineralization.