Effect of incisal loading during orthodontic treatment in adults: A randomized control trial

Abstract

Objective: To measure the changes in tooth mobility, alveolar bone, and receptor activator of nuclear factor kappa-B ligand (RANKL)/osteoprotegerin (OPG) in the gingival crevicular fluid (GCF) during orthodontic treatment to regain incisal function in the presence and absence of biting exercises.

Materials and methods: Thirty-six females (42.3 ± 6.5 years old) with periodontally compromised upper incisors received orthodontic treatment to obtain ideal incisor relationships. Eighteen subjects in the experimental biting exercise group were instructed to bite a soft plastic roll for 5 min/d; the 18 control subjects were not given plastic rolls. Alveolar bone thickness, height, and density around the upper incisors were assessed at three root levels using cone-beam computed tomography. GCF was collected at the labial and palatal sites of the upper incisors at pretreatment (T0), end of treatment (T1), 1 month after T1 (T2), and 7 months after T1 (T3). RANKL/OPG was determined using enzyme-linked immunosorbent assays.

Results: Labial and palatal bone thickness significantly increased (>twofold) from T1 to T3 in the experimental group at all three root levels (all P < .05). Bone thickness correlated negatively with RANKL/OPG ratio between T1 and T2 ( P < .05). Tooth mobility, bone height, and density were not significantly different between T1 and T3.

Conclusions: Biting exercises significantly increased bone thickness but did not affect tooth mobility, bone height, or density. The RANKL/OPG ratio decreased 1 month after treatment (T2) and correlated with increased bone thickness. ( ClinicalTrials.in.th TCTR20170625001).

Keywords: Bone remodeling; Cone-beam computed tomography; Exercise therapy; Osteoprotegerin; Periodontal disease(s)/periodontitis; RANK ligand.

Figure 1

CONSORT 2010 flow diagram.

Figure 2

Measurement of (A) bone thickness and density at three levels, (B) bone thickness, (C) cortical and trabecular bone density, (D,E) bone height, and (F) root length on CBCT images.

Figure 3

Mean (±standard deviation) difference in alveolar bone thickness at (A) labial and (B) palatal sites between T1 and T3.

Figure 4

Mean (±standard deviation) RANKL/OPG ratio in GCF in control and experimental groups at (A) labial and (B) palatal sites between T0 and T3.

Figure 5

CBCT of treated teeth showing fenestration remaining in a patient from the control group (A) and absence of fenestration in a patient from the experimental group (B) at T1 to T3.