Dr. Raphael and colleagues raise a number of questions regarding the experience sampling methods we reported on in our article. While we find the questions interesting, we don’t feel they have merit. As noted by Dr. Raphael and colleagues, we did not attempt to measure "bruxism" specifically. Even a casual reader of the article will find that the focus was not on "daytime bruxism," but on parafunctions, defined in our article as tooth contact. We are not enamored of daytime bruxism as an area of study because the term is very poorly defined, the scope of behaviors associated with the term is likely to be large and there is terminological confusion of daytime bruxism with nocturnal bruxism.
We agree that measures used in dental research should be subject to ongoing validation. However, we are not convinced that the approach proposed by Dr. Raphael and colleagues (EMG measures or actigraphy) would yield useful data for validation experience sampling approaches. The ability of EMG measures or actigraphy to differentiate between types of daytime bruxism is difficult, at best, and will need to be performed in a controlled laboratory setting for the highest quality results. Studies performed in laboratories can be technically sophisticated, but they remove one of experience sampling’s greatest virtues: the ability to assess immediately behaviors in the natural environment.
Reactivity of measurement is always a concern when it comes to the measurement of human activities or states. Our approach was to consider which type of measurement was more reactive: the placement of an intraoral appliance in the mouth, attaching electrodes on the face, placing an actigraph capable of monitoring oral parafunctions on a subject or making a check-mark on a notecard-sized questionnaire? If reactivity is a concern with experience sampling, those concerns should be even greater with the approaches suggested by Dr. Raphael and colleagues.
JADA readers should be assured that we took several steps in the study to minimize bias and reactivity. Instructions to the individuals who participated in the study were provided by a research assistant blinded to their group assignment. The research assistant followed a script while giving instructions.
Finally, we and others1–2 have shown that EMG activity follows clear and predictable patterns when subjects are asked to make tooth contact at different levels of force. We’ve also recently completed a study showing that individual subjects show very little variability in EMG activity when asked to make tooth contact across different levels of force.
In short, our study was not about daytime bruxism, and the solutions proposed by Dr. Raphael and colleagues for examining the validity of experience sampling methods are problematic at best, do not solve the problem of reactivity and lack external validity.
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