Abstract
Low-level laser therapy (LLLT) may have an effect on the pain associated with orthodontic treatment. The aim of this study was to evaluate the effect of LLLT on pain and somatosensory sensitization induced by orthodontic treatment. Forty individuals (12–33 years old; mean ± standard deviations: 20.8 ± 5.9 years) scheduled to receive orthodontic treatment were randomly divided into a laser group (LG) or a placebo group (PG) (1:1). The LG received LLLT (810-nm gallium-aluminium-arsenic diode laser in continuous mode with the power set at 400 mW, 2 J·cm–2) at 0 h, 2 h, 24 h, 4 d, and 7 d after treatment, and the PG received inactive treatment at the same time points. In both groups, the non-treated side served as a control. A numerical rating scale (NRS) of pain, pressure pain thresholds (PPTs), cold detection thresholds (CDTs), warmth detection thresholds (WDTs), cold pain thresholds (CPTs), and heat pain thresholds (HPTs) were tested on both sides at the gingiva and canine tooth and on the hand. The data were analysed by a repeated measures analysis of variance (ANOVA). The NRS pain scores were significantly lower in the LG group (P = 0.01). The CDTs, CPTs, WDTs, HPTs, and PPTs at the gingiva and the PPTs at the canine tooth were significantly less sensitive on the treatment side of the LG compared with that of the PG (P < 0.033). The parameters tested also showed significantly less sensitivity on the non-treatment side of the LG compared to that of the PG (P < 0.043). There were no differences between the groups for any quantitative sensory testing (QST) measures of the hand. The application of LLLT appears to reduce the pain and sensitivity of the tooth and gingiva associated with orthodontic treatment and may have contralateral effects within the trigeminal system but no generalized QST effects. Thus, the present study indicated a significant analgesia effect of LLLT application during orthodontic treatment. Further clinical applications are suggested.
Highlights
The most common problems for patients during orthodontic treatment are pain and discomfort evoked by the appliances and mechanical loading.[1,2,3,4,5,6] It has been reported that ~90% of orthodontic patients will experience pain during orthodontic treatment.[7]
There were no significant differences between the laser group (LG) and placebo group (PG) at baseline for cold detection threshold (CDT) (ANOVA; F = 1.57, df = 1, P = 0.215), cold pain threshold (CPT) (ANOVA; F = 0.26, df = 1, P = 0.223), warmth detection threshold (WDT) (ANOVA; F = 0.28, df = 1, P = 0.597), heat pain threshold (HPT) (ANOVA; F = 0.13, df = 1, P = 0.721), pressure pain threshold (PPT) at the gingiva (ANOVA; F = 1.03, df = 1, P = 0.315), or pressure pain threshold (PPT) at the canine tooth (ANOVA; F = 0.916, df = 1, P = 0.347)
quantitative sensory testing (QST) at the hand There were no significant differences between the LG and PG for the CDT (ANOVA; F = 0.005, df = 1, P = 0.945), WDT (ANOVA; F = 0.33, df = 1, P = 0.572), CPT (ANOVA; F = 0.03, df = 1, P = 0.864), HPT (ANOVA; F = 0.001, df = 1, P = 0.976) and PPT (ANOVA; F = 1.25, df = 1, P = 0.274)
Summary
The most common problems for patients during orthodontic treatment are pain and discomfort evoked by the appliances and mechanical loading.[1,2,3,4,5,6] It has been reported that ~90% of orthodontic patients will experience pain during orthodontic treatment.[7]. The pain usually begins within 4 h after the force is applied, reaches a peak after ~24 h, and dissipates by day 7.11,12 The intensity of the pain during orthodontic treatment is sometimes reported to be even stronger than the pain related to dental extractions.[13]
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