Validation of three-dimensional digital model superimpositions based on palatal structures in patients with maximum anterior tooth retraction following premolar extraction

Abstract

Objective: This study aimed to evaluate the superimposition accuracy of digital modes for measuring tooth movement in patients requiring anterior retraction after premolar extraction based on the proposed reference regions. Methods: Forty patients treated with bilateral maxillary first premolar extraction were divided into two groups: moderate retraction (< 7.0 mm) and maximum retraction (≥ 7.0 mm). Central incisor displacement was measured using cephalometric superimpositions and three-dimensional (3D) digital superimpositions with the 3rd or 4th ruga as the reference point. The Wilcoxon signed-rank test and linear regression analyses were performed to test the significance of the differences and relationships between the two measurement techniques. Results: In the moderate retraction group, the central incisor anteroposterior displacement values did not differ significantly between 3D digital and cephalometric superimpositions. However, in the maximum-retraction group, significant differences were observed between the anteroposterior displacement evaluated by the 3rd ruga superimposition and cephalometric methods (p < 0.05). Conclusions: This study demonstrated that 3D digital superimpositions were clinically as reliable as cephalometric superimpositions in assessing tooth movements in patients requiring moderate retraction. However, the reference point should be carefully examined in patients who require maximum retraction.

Superimposition of virtual models using palatal rugae and maximum habitual intercuspation

“…However, although the literature is vast in works that used reference points and regions in the maxilla, they differ regarding which region presents more stability, and none had been designated as gold standard. 15 …”

“… 7 Some studies suggested concomitant palatal rugae alterations in the anterior and lateral end area following tooth movement, especially in patients who underwent tooth extraction. 15 , 16 …”

“…The areas in the maxilla that seems to be the most stable for superimposition are the medial thirds of the third palatine rugae, including a 5 mm area dorsal to it, 16 and a region that includes the entire rugae, with lateral margins located within 5 mm of the gingival margins, and a distal margin that does not extend beyond the first molars. 4 , 10 , 15 , 17 …”

“…However, although the literature is vast in works that used reference points and regions in the maxilla, they differ regarding which region presents more stability, and none had been designated as gold standard. 15 Different palatal regions have been suggested as parameters for superimposition, and the reference area used has considerable effect on the superimposition result, as well as on the number of reference landmarks. 7 Some studies suggested concomitant palatal rugae alterations in the anterior and lateral end area following tooth movement, especially in patients who underwent tooth extraction.…”

“…7 Some studies suggested concomitant palatal rugae alterations in the anterior and lateral end area following tooth movement, especially in patients who underwent tooth extraction. 15,16 Holz IS, Carvalho FAR, Almeida RCC -Superimposition of virtual models using palatal rugae and maximum habitual intercuspation 7 Dental Press J Orthod. 2024;29(2):e24spe2…”