Cone beam computed tomography evaluation of distance from cementoenamel junction to alveolar crest before and after nonextraction orthodontic treatment

Abstract

Objective: To evaluate the distance between the cementoenamel junction and the alveolar bone crest before and after orthodontic treatment using cone beam computed tomography (CBCT). Materials and Methods: The sample comprised 30 patients with Angle Class I malocclusion and mild to moderate crowding. The study database comprised dental CBCT scans obtained before and after orthodontic treatment. The distance between the cementoenamel junction to the bone crest of the buccal (n 5 720) and lingual (n 5 720) surfaces was measured in 24 teeth for each patient using a specific software tool (Xoran version 3.1.62). The Wilcoxon test was used for statistical analysis, and the level of significance was set at P , .05. Results: The distance between the cementoenamel junction and the bone crest increased in 822 (57%) of the 1440 surfaces after orthodontic treatment. The buccal surface of the lower central incisors had the greatest frequency of increased distance (75%), and the lingual surface of lateral incisors had the lowest (40%). The distance between the cementoenamel junction and the alveolar bone crest was greater than 2 mm (alveolar bone dehiscence) in 162 (11%) of the 1440 surfaces before orthodontic treatment and in 279 (19%) after treatment. Conclusion: The distance from the cementoenamel junction to the bone crest changed after orthodontic treatment; the distance was greater than 2 mm in 11% of the surfaces before treatment and in 19% after treatment. (Angle

Bone dehiscence formation during orthodontic tooth movement through atrophic alveolar ridges

“…(Table 1; Figure 4) Buccal bone loss from 0.2 to 0.8 mm was reported in the orthodontic treatment of adults not involving atrophic areas. 13,18,22 Although the present study evaluated mainly lower first and second premolars, descriptive and dispersion graphs indicated a variable response of buccal and lingual bone loss in all types of tooth movement (Table 5; Figures 5 and 6). Isolated statistical comparisons per tooth type were limited in the study due to the sample characteristics and size.…”

“…Davies et al 15 considered a bone defect to be present with at least 4 mm of bone loss, while Leung et al 16 considered 3 mm of bone loss to be a dehiscence. Prevalence of dehiscence has varied significantly among studies 13,[17][18][19][20] due to variability in methods and samples (8.19%, 19 40.4%, 20 50%, 11,18 and 71.61% 21 ). Nevertheless, there is consensus that the prevalence of dehiscence increases with age.…”

“…13,22,23 Orthodontic treatment is also a factor affecting dehiscence prevalence. 11,13,18 Jäger et al 13 observed that, before treatment, 20% exhibited such bone defects, increasing to 90% of the patients with at least one tooth with dehiscence after orthodontic intervention.…”

“…6 On the contrary, CBCT reconstructions allow three-dimensional evaluation of both crestal height and thickness. 6,11,13,[16][17][18] It has been reported that when the cortical plate is thinner than 0.5 mm, a false-positive diagnosis for dehiscence might be generated. 24 CBCT reconstruction was reported to only have about 70% accuracy for distinguishing between the presence and absence of this condition.…”

“…25 It is well known that the smaller the voxel size, the richer the imaging details. [16][17][18]25,26 Menezes et al 26 suggested that there was adequate precision for crestal bone measurements only when the voxel size was 0.3 mm or smaller. Also it is well known that the smaller the voxel size, the higher the ionizing radiation.…”