We read with great interest the case report entitled “Long-term stability of maxillary group distalization with interradicular miniscrews in a patient with a Class II Division 2 malocclusion” (Kuroda S, Hichijo N, Sato M, Mino A, Tamamura N, Iwata M, et al. Am J Orthod Dentofacial Orthop 2016;149:912-22) in the June issue. We have a few questions.
First, the authors showed a pretreatment lateral cephalogram that shows very little space for the placement of miniscrews. The roots of the first quadrant maxillary second premolar and first molar seem to be converging toward each other (Fig 3, pretreatment lateral cephalogram). Were any special measures taken to diverge the roots of the maxillary second premolar and first molar? Was the space between the maxillary second premolar and first molar roots quantified before the maxillary arch distalization?
Second, the authors mentioned in the Discussion that the miniscrews were placed at the mesial alveolus of the first premolar, whereas in the Figure 5, A , they appear to be at the mesial alveolus of the first molar.
Third, they mentioned that the maxillary second premolar root could pass through the lingual side of the obliquely placed miniscrews. What was the angulation of the miniscrews in relation to the root surface? Was CBCT or any other method done for this patient to quantify the buccolingual thickness of the alveolar basal bone to prevent root contact with the maxillary second premolar?
Finally, the mandibular plane angle remained unchanged from pretreatment to posttreatment. Since both maxillary arch distalization and mandibular molar mesialization lead to an increased mandibular plane angle, were any special measures taken to prevent opening up the mandibular plane angle?
Thank you again for writing this interesting article.