As orthodontists, we are continually confronted with the level of oral hygiene in our patients. The clinical implications of poor oral hygiene in orthodontic patients are wider. Some prior evidence indicated no beneficial effects of orthodontic treatment on periodontal health, but small detrimental effects. Hence, it may be interesting to know which type of orthodontic appliance could produce the least affliction to the periodontium. Although the authors of this study reasoned the need for the current randomized clinical trial based on earlier methodologic limitations, we find certain flaws still persisting. However, we have no intention to discount the efforts of the authors but would like clarifications on aspects that could help advance the research on this interesting topic and merit reproducibility of the research.
First, we acknowledge the authors for an authoritative conclusion with reference to clear aligners, even though the study was partially funded by Align Technology, thus minimizing any associated sponsorship bias. However, the authors failed to discuss sufficiently the results obtained with clear aligners when relating to previous investigations and missed citing an important previous work (randomized trial) published in the Journal of Orofacial Orthopedics in 2015 (and facilitated citation bias).
Randomized controlled trials are considered a requisite for higher levels of evidence-based dentistry in contemporary research. To reiterate, we do strongly agree, but are a little clueless with respect to the appropriateness of subjecting the current investigation to this protocol (randomized methodology). The ethical recruitment of patients requires clinical equipoise. The patient’s choice of appliance type (clear aligners, self-ligated braces, and elastomeric-ligated braces) could not be considered, and they were randomly allocated to 1 of the 3 groups, which could be a bias. A patient who prefers self-ligation brackets could be denied this type due to randomization. Also, concurrent control and strict eligibility criteria would merit a high-quality investigation. We would like to know why no control was used in this study. With regard to eligibility criteria, how did the authors manage to identify subjects with the ability to maintain oral hygiene? After all, maintaining oral hygiene is subjective and circumstantial. One important criterion could be to categorize the patients based on similar gingival subtypes to minimize individual variability.
We were terribly confused with regard to the sample numbers subjected to statistical analysis. As per the CONSORT diagram, the total who received allocated intervention was 61 (10 participants did not receive the allocated intervention after randomization of 71 eligible candidates). It was not clear how the participants who were lost to follow up (2 in the SLB group and 1 in the ELB group) managed to be subjected to the statistical computation. There were considerable errors noted in the Table I. Those who received the allocated intervention should be 61 (as per CONSORT) and not 68. We are doubtful if this could have influenced the rest of the parameters in Table I.
There were errors associated with misrepresentation of figure numbers (Figs 1 and 2) throughout the article.
The investigation could be considered more meaningful if the authors did attempt periodontal measurements in not just the maxillary second premolar but other teeth as well. Also, it is not clear whether left or right maxillary second molar or other surfaces were considered. However, there is no uniform consensus with reference to the choice of measurement site among the other investigations as well. Considering the critical importance of such investigations, we believe a more generalized approach including maximal possible sites for measurement should be appropriate.
Studies of this nature are closely dependent on many intricate details including the patient’s psychosocial makeup, the operator’s social engagement (communication and rapport) during patient attendance, and the operator’s technical competency (no flash resin surrounding the bracket base). Thus, to eliminate the heterogeneity and facilitate advancement of further research, a multi-operator (residents or faculty) scenario and orthodontists as examiners as noted in this investigation should be avoided. In our opinion, a reliable high-yield approach would be 1 operator (preferably an experienced clinician) for all the samples and 1 periodontist to record the measurements.
We strongly believe, more than randomization, the standardization of the above factors could merit a high-quality research to understand which orthodontic appliance is best for oral hygiene.