Now Reading
Concerns regarding the published article “Effect of dopaminergic agonist group of drugs in treatment of sleep bruxism: A systematic review” by Bhattacharjee et al

Concerns regarding the published article “Effect of dopaminergic agonist group of drugs in treatment of sleep bruxism: A systematic review” by Bhattacharjee et al

Concerns regarding the published article “Effect of dopaminergic agonist group of drugs in treatment of sleep bruxism: A systematic review” by Bhattacharjee et al

Journal of Prosthetic Dentistry, 2021-07-01, Volume 126, Issue 1, Pages 134-135, Copyright © 2021 Editorial Council for the Journal of Prosthetic Dentistry

With great interest, we have read the recently published systematic review on the effect of dopaminergic agonists in the treatment of sleep bruxism by Bhattacharjee et al. The authors are to be applauded for their thorough assessment of the available literature on this intriguing and highly relevant topic. Although we fully agree with the authors’ conclusion that owing to limited evidence and conflicting results, no significant conclusions can be drawn, we do have some concerns that we would like to bring forward to the readership of your journal. Our concerns are related to a noted lack of precision in the citing of references and the scoring of risk of bias.

First, the authors are not very precise in their choices and usage of some of their references. The authors start their introduction with a definition of sleep bruxism. Thereby, they refer to the International Classification of Sleep Disorders, third edition (ICSD-3). However, we would like to point out that the ICSD-3 adopted the definition that was previously proposed by an international group of bruxism experts. Similarly, the authors cite the definition published in the Guidelines for Orofacial Pain, sixth edition, which again is the definition proposed by Lobbezoo et al. In our opinion, it would have been the habitual mode to refer to the original publication of the bruxism definition as well. In addition to this definition issue, the authors state that “Previously, occlusal interferences and malocclusion were believed to be major factors responsible for sleep bruxism.” To support that statement, the authors refer, among others, to a publication by Lobbezoo et al, while in that article, the authors conclude that “… orofacial morphology of sleep bruxers does not differ from that of nonbruxers.” Hence, this is a typical example of incorrect usage of a reference.

Second, the authors have misjudged the risk of bias of 2 of their included studies. , They used the Cochrane Collaboration’s tool for assessing risk of bias in a randomized trial. , That tool assesses the risk of bias in several domains, among which random sequence generation and concealment of allocation sequence. The risk of bias per domain is scored as “low risk of bias,” “some concerns” (that is, unclear risk of bias owing to lack of information, uncertainty, and so on), or “high risk of bias.” In the study by Lobbezoo et al, , it was stated that “The order of administration was reversed in half the patients.” This does, however, not mean that randomization and concealment were not applied. In fact, computer-generated block randomization was used to establish the allocation sequence, which was concealed by an independent coworker. It is correct that this information on random sequence generation and allocation sequence concealment is lacking in the study by Lobbezoo et al. , However, this should have yielded “some concerns” scores instead of “high risk of bias” scores as carried out by Bhattacharjee et al. Consequently, the overall risk-of-bias judgment should have been “some concerns” as well, not “high risk of bias.” Apart from that, the authors could also have decided to contact us in which case we would have explained our modus operandi . Clearly, contacting authors for additional information is not feasible in large-scale systematic reviews, but in this case, only a single author needed to be approached. This rather common practice (we have received several of such requests over the years) would have led to a low overall risk-of-bias score for both articles.

See Also

In short, while Bhattacharjee et al. selected and elaborated an important and highly relevant topic, we have tried to illustrate in this letter that precision in the choices and usage of references as well as in risk-of-bias scoring is essential to do justice to the involved publications.


  • 1. Bhattacharjee B., Saneja R., Bhatnagar A., Gupta P.: Effect of dopaminergic agonist group of drugs in treatment of sleep bruxism: A systematic review. J Prosthet Dent 2021;
  • 2. American Academy of Sleep Medicine: International Classification of Sleep Disorders.3rd ed.2014.American Academy of Sleep MedicineWestchesterpp. 303-311.
  • 3. Lobbezoo F., Ahlberg J., Glaros A.G., Kato T., Koyano K., Lavigne G.J., et. al.: Bruxism defined and graded: An international consensus. J Oral Rehabil 2013; 40: pp. 2-4.
  • 4. De Leeuw R., Klasser G.D.: Orofacial Pain. Guidelines for Assessment, Diagnosis, and Management.6th ed.2008.Quintessence Publishing Co, Inc.Chicago, ILpp. 229.
  • 5. Lobbezoo F., Rompré P.H., Soucy J.P., Iafrancesco C., Turkewicz J., Montplaisir J.Y., et. al.: Lack of associations between occlusal and cephalometric measures, side imbalance in striatal D2 receptor binding, and sleep-related oromotor activities. J Orofacial Pain 2001; 15: pp. 64-71.
  • 6. Lobbezoo F., Lavigne G.J., Tanguay R., Montplaisir J.Y.: The effect of the catecholamine precursor L-dopa on sleep bruxism: A controlled clinical trial. Mov Disord 1997; 12: pp. 73-78.
  • 7. Lobbezoo F., Soucy J.P., Hartman N.G., Montplaisir J.Y., Lavigne G.J.: Effects of the dopamine D2 receptor agonist bromocriptine on sleep bruxism: Report of two single-patient clinical trials. J Dent Res 1997; 76: pp. 1611-1615.
  • 8. Higgins J.P.T., Altman D.G., Gøtzsche P.C., Jüni P., Moher D., Oxman A.D., et. al.: The Cochrane Collaboration’s tool for assessing risk of bias in randomised trials. BMJ 2011; 343: pp. d5928.
  • 9. Higgins J.P.T., Savović J., Page M.J., Elbers R.G., Sterne J.A.C.: Chapter 8: Assessing risk of bias in a randomized trial.Higgins J.P.T.Thomas J.Chandler J.Cumpston M.Li T.Page M.J. et. al.Cochrane Handbook for Systematic Reviews of Interventions version 6.2 (updated February 2021).2021.CochraneLondon, United Kingdom:
View Comments (0)

Leave a Reply