Articles Vol. 67 No. CĐ5-NCKH 04/05/2026

ASSESSMENT OF ARCH SIZE CHANGES USING SOFTWARE ON ORAL SCAN MODELS IN ORTHODONTIC PATIENTS UNDERGOING MINIMAL MOLAR TOOTH EXTRACTION

Truong Hoang Le Thuy1,2, Vu Quoc Vuong3,4, Nguyen Quang Minh5,6, Nguyen Vu Anh5,6, Vo Truong Nhu Ngoc3,4
1 Faculty of Dentistry, Hong Bang International University
2 Khoa Răng Hàm Mặt, Trường Đại học Quốc tế Hồng Bàng
3 Nhu Ngoc Dental Clinic
4 Nha khoa Như Ngọc
5 Faculty of Dentistry, Vietnam National University of Medicine and Pharmacy, Hanoi
6 Khoa Răng Hàm Mặt, Trường Đại học Y Dược, Đại học Quốc Gia Hà Nội
DOI: 10.52163/yhc.v67iCD5.5015
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Keywords
Orthodontics, premolar extraction, 3D scanner, dental arch dimensions, canine interproximal width, molar interproximal width.
Abstract

Objective: To quantitatively assess the changes in dental arch dimensions in orthodontic patients who underwent extraction of premolar teeth, using analysis software on digital dental models generated by an intraoral 3D scanner system.

Methods: A retrospective study was conducted on 27 patients who completed orthodontic treatment at Nhu Ngoc Dental Clinic. The 3D scan data of both upper and lower arches (.STL files) before treatment (T0) and after treatment (T1) were measured using digital software to compare the following dimensions: canine interproximal width, molar interproximal width, arch length, and arch perimeter.

Results: The study observed a significant reduction in arch length and perimeter after orthodontic treatment (p < 0.05). However, the inter-canine width tended to remain stable, indicating that the dental arch was not narrowed in the anterior region. In contrast, the inter-molar width significantly decreased due to the loss of physiological anchorage.

Conclusion: Premolar extraction in orthodontic treatment primarily affects the anterior-posterior arch dimensions and the posterior region's width. However, the canine interproximal width is preserved, contributing to maintaining the aesthetic of the smile.

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