Morphometric evaluation of the alveolar bone around central incisors during surgical orthodontic treatment of high‐angle skeletal class III malocclusion

Abstract

ObjectivesTo evaluate morphometric characteristics of alveolar bone around the incisors of high‐angle skeletal class III patients receiving surgical orthodontic treatment.Setting and Sample PopulationThirty high‐angle skeletal class III patients (mean age, 20.94 ± 3.25 years) underwent cone‐beam computed tomography before treatment (T0), after pre‐surgical orthodontic treatment (T1) and after treatment (T2).Materials and MethodsThe vertical bone level (VBL), alveolar bone thickness (ABT), alveolar bone area (ABA) and position of upper and lower central incisors (UCIs and LCIs) were evaluated. The ABT included five levels (4, 6, 8 mm from the cemento‐enamel junction, midroot and root apex level). One‐way repeated measures ANOVA with Bonferroni's multiple‐comparison test and matched t test was performed to compare variables.ResultsBefore treatment, the average labial ABT was approximately 1 mm in UCIs and 0.38 ~ 0.79 mm in LCIs, and the VBL of the LCIs was over 2 mm. After treatment, the VBL increased by 2.19 ± 1.96 mm (P < .001) on the lingual side of UCIs and 2.78 ± 2.29 mm and 3.09 ± 2.52 mm on the labial and lingual sides of LCIs, respectively (all P < .001). ABT at every level decreased significantly, decreasing by 1.66 ± 1.93 mm at the 8 mm level of UCIs and 1.06 ± 1.01 mm at the apex of LCIs (P < .001). The lingual ABA of UCIs and LCIs decreased by over 50% (P < .001).ConclusionsIn high‐angle skeletal class III patients, the condition of alveolar bone around UCIs and LCIs was extremely poor before treatment. Further alveolar bone resorption occurred during surgical orthodontic treatment. More attention should be paid to the movement of anterior teeth in cases of severe alveolar bone loss.

Bone Remodeling during Orthodontic Movement of Lower Incisors—Narrative Review

“…What is more interesting, the thickness of the alveolar bone was reduced after proclination (total bone thickness) [ 23 ] and retraction (lingual and buccal) of lower anterior teeth [ 35 , 36 ]. The results were similar for adults patients [ 26 , 28 , 31 , 32 , 33 , 34 ]. The only “gain” in the measured variable was for buccal thickness of mandibular incisor in bimaxillary protrusion patients treated with extraction therapy [ 29 , 30 ].…”

“…High-angle, class III patients are characterized by extremely thin alveolar bone in the anterior part of the mandible. During the presurgical phase of treatment, Ma et al reported 1.57 mm of buccal and 2.82 mm of lingual vertical bone loss, as well as 7.11 ± 5.16 mm 2 alveolar bone area loss on the lingual side [ 34 ].…”

“…Moreover, incisors are subjected to significant forward movement before surgery. The bone loss, in terms of height and thickness, occurs not only before surgery [ 26 , 34 ] but continues until the completion of treatment [ 34 ]. Buccal thickness did not change in Yao et al [ 26 ] and Lee et al [ 28 ]; however, this can be explained by the measurement method used.…”

“…Few studies objectively measured the range of tooth movement [ 24 , 37 ]. Also, the change in inclination of incisors measured on lateral cephalometric images [ 23 , 27 , 34 , 35 , 36 ] did not provide information regarding changes for each incisor individually. Few studies evaluated the change in inclination for each tooth in CBCT or digital dental models [ 23 , 25 , 26 , 28 , 31 , 32 , 33 ].…”

Comparison of alveolar bone width and sagittal tooth angulation of maxillary central incisors in Class I and Class III canine relationships: a retrospective study using CBCT

“…In hyperdivergent women, available palatal bone may be smaller than normal in the middle and posterior areas [ 31 ]. Moreover, the alveolar bone thickness around incisors can also be originally or developmentally thinner in skeletal class III malocclusion patients [ 32 ]. In this study, maxillary central incisor’ palatal alveolar bone with Class III canine relationship were significantly thinner at both mid-root and apical level, which may be accounted for by the palatal hypoplasia associated with Class III skeletal deformity as described in previous studies.…”