Evaluation of dentoalveolar changes following maxillary incisor intrusion with one vs two anterior miniscrews in subjects with gummy smile: a randomized clinical trial

Abstract

Objectives: To examine dentoalveolar changes following intrusion of maxillary incisors with one or two anterior miniscrews in subjects with gummy smile and deep bite.

Materials and methods: Forty-three subjects were selected and divided into two groups: group I (22 subjects: 15 women, 7 men; mean age 30 ± 10 years) received one miniscrew between the upper central incisors, and group II (21 subjects: 16 women, 5 men; mean age 30 ± 10 years) received two miniscrews between the canines and lateral incisors. Dentoalveolar parameters, including amount of intrusion, root resorption, incisor inclination, alveolar bone thickness, and buccal alveolar crest height (cementoenamel junction to labial alveolar crest), were evaluated using cone-beam computed tomography scans obtained before and after intrusion. The intergroup comparison was analyzed using a paired t-test and unpaired t-test to determine significant changes within and between groups.

Results: The amount of intrusion was significantly greater in group II than in group I (P < .05). No statistically significant differences were found between groups I and II for changes in incisor inclination, labial bone thickness, and buccal alveolar crest height (P > .05).

Conclusions: Maxillary central and lateral incisor intrusion was significantly greater in subjects treated with two miniscrews. Root resorption of the maxillary central incisors was notably greater in subjects with one miniscrew, while maxillary lateral incisor resorption was greater in subjects treated with two miniscrews.

Keywords: 3-dimensional diagnosis and treatment planning; Intrusion; Microimplant; Miniscrew; Randomized clinical trial.

Figure 1

CONSORT flow diagram.

Figure 2

Guiding pointer used for correct miniscrew placement.

Figure 3

Use of guiding pointer in group II. (A) Guiding pointers. (B) Periapical radiograph with guiding pointers. (C) Periapical radiograph with miniscrews. (D) Two miniscrews loaded for intrusion with elastic chain.

Figure 4

Preintrusion (T0) intraoral photographs, group I. (A) Right buccal. (B) Frontal. (C) Left buccal.

Figure 5

Preintrusion (T0) intraoral photographs, group II. (A) Right buccal. (B) Frontal. (C) Left buccal.

Figure 6

CBCT orientation of three planes of space.

Figure 7

CBCT measurements: (A) vertical incisor position, (B) incisor inclination, (C) incisor total length, (D) labial and palatal bone thickness.

Figure 8

Clinical assessment of gummy smile correction following intrusion. (A) Preintrusion. (B) Postintrusion.