To: Editor, The Angle Orthodontist Re: Efficacy of injectable platelet-rich plasma in reducing alveolar bone resorption following rapid maxillary expansion: A cone-beam computed tomography assessment in a randomized split-mouth controlled trial. Eyad B. Alomari; Kinda Sultan. Angle Orthod. 2019; 89: 705–712.

Thank you for publishing this interesting study. However, we would like further clarification regarding some aspects of the study.

  1. What were the criteria used to classify the patients as having clinical maxillary transverse deficiency? Were the criteria dental or skeletal and how were they measured?

  2. How much variation was there among patients in the amount of expansion that was required? The mean amount that was attained was not specified in the paper. It is known that post-expansion alveolar bone defects and the buccolingual inclination of the posterior teeth vary with the amount of expansion attained. Can you evaluate whether there was an association among these factors in the study patients?

  3. Can you elaborate further on the PRP fold, dosage, exact location, technique (intraligamentary or submucosal) and amount (volume) of injection per site, as these were not described in detail in the paper.

We would appreciate your further comments on the details of the study.