To: Editor, The Angle Orthodontist

Re: Evaluation of the use of low-level laser therapy in pain control in orthodontic patients: A randomized split-mouth clinical trial. The Angle Orthodontist. 2016; 86:193-198.

We read this paper with great interest. The article addressed many issues associated with the efficacy of application of low level laser (LLLT) in pain control and we appreciated the systematic manner in which the Randomized Clinical Trial was performed. We would like clarifications regarding some aspects of the study.

  • 1.

    The conclusion was that there was a significant reduction in pain in the exposed side of the patients when compared to the control/placebo side at all time intervals. Was this conclusion based on Table 3, since the VAS data in Tables 1 and 2 suggest otherwise? (The median VAS values for T1 and T2 reported in Tables 1 and 2 are higher in the exposed group than the placebo group which is contrary to the data in Table 3). Perhaps you can explain in more detail the values in the Tables.

  • 2.

    P values between T0 and T1 and T1 and T2 for Table 2 have been mentioned but did not discuss P values for the data in Table 1. Which time points were significantly different?

  • 3.

    Can you elaborate on how the maximum and minimum values given in Table 4 were arrived at? (the minimum value is uniformly −100 for all groups and time periods).

  • 4.

    It was mentioned that based on Table 4, there was a decrease in pain by 13.89% in the EG group and 44.39% increase in the PG. But the numerical data in Table 3 suggests an increase in both the groups. Furthermore, are you referring to a reduction in pain intensity or the proportion of patients in whom pain was reduced?

  • 5.

    The study involved placement of separators on the right side initially and then on the left side one week later. Since patients had already had the experience previously, do you think that the patient's response to the pain at the second exposure would be different?

  • 6.

    Was the presence of third molars and its influence on the tightness of contacts evaluated as a possible confounding factor? Could this have affected the pain intensity?

Once again we appreciate this interesting paper investigating the efficacy of application of LLLT in pain control.