Letter to the Editor

To: Editor, The Angle Orthodontist

Re: Effect of injectable platelet-rich fibrin (i-PRF) on the rate of tooth movement: A randomized clinical trial; Emire Aybuke Erdur; Kuter Karakaslı; Elif Oncu; Bahadır Ozturk; Sema Hakkı, Angle Orthod. 2021;91:285-292.

We appreciate the extensive work of the authors on this evolving topic. We would like to pose a few questions regarding the study:

1. No attrition was reported in the study. Did all 20 patients attend all of the follow-up visits?

2. Was there any blinding of the investigators done to alleviate bias in treatment or measurements?

3. The collectible amount of GCF is 0.01mg in 3 minutes¹. Was it possible to collect 1ml of GCF by inserting the filter strip for 10 seconds?

4. Only about 0.2ml of local anesthetic solution is required per root to anesthetize a tooth by intraligamentary injection². Hence, was it possible to give 2ml of intraligamentary i-PRF?

Thank you for considering our questions and providing us more information on this topic.