Smear layer removal from root canal system

Sir, I read with great interest the article entitled “Endodontic smear layer removal using conventional and endodontic microbrush device: A scanning electron microscope and profilometer study” by Nallathambi et al., which has been published in your esteemed journal (Saudi Endodontic Journal 2017; 7(2):102-9). It was a clinically relevant study, comparing the different irrigation techniques in removal of smear layer from root canal system. However, I feel there are few major drawbacks in this study which can skew the results. Few of my thoughts which I would like to share are as follows: The results of the study demonstrated that in the control group which was not instrumented; smear layer was found to be maximum compared to the test groups. This is really surprising. When the root canals were not instrumented in the control group, how can smear layer be formed?[1] It has been well proven in endodontic literature that the use of a chelating agent/acid is mandatory for the removal of smear layer along with NaOCl.[2,3] In this study, the removal of canal wall smear layer was evaluated without using any chelating agents. The methodology employed in this study does not simulate the clinical scenario at all Time of root canal irrigation, type of needle used, and the depth of needle insertion into the root canal are some of the important factors which determine the efficacy of an irrigation technique in removal of smear layer. These factors were not taken into consideration in this study In this study, only one examiner evaluated the smear layer scores. Ideally, two or three independent operators who are blinded to the study groups should score the standard error of measurement images, and their reliability should be evaluated.[4] Hence, authors can incorporate all these above-mentioned parameters and perform further similar studies to appreciate for the better performance of the microendo brush in the removal of the canal wall smear layer. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.