Labial and palatal alveolar bone changes during maxillary incisor retraction at the Universitas Sumatera Utara Dental Hospital

Abstract

Background: The fundamental concept of tooth movement during orthodontic treatment is the occurrence of bone remodelling accompanied by tooth movement in equal proportions. The thickness of the alveolar bone, which supports incisors, is important in estimating the direction of tooth movement. Purpose: The study aimed to measure labial and palatal alveolar bone thickness changes after maxillary incisor retraction using lateral cephalograms. Methods: Cephalograms of 40 patients (18.58 ± 4.2 years) with skeletal Class I bimaxillary protrusion after maxillary first premolar extraction for insisivus retraction had been taken before (T0) and after (T1) orthodontic treatment. Changes in alveolar bone thickness were measured in linear and angular directions and then analysed with Spearman correlative analysis. Then the samples were separated into two groups based on the type of tooth movement (tipping and torque), and then the data were analysed using Wilcoxon analysis to see differences in the bone thickness (p<0.05). Results: There was a significant difference in the apical palate (p<0.05) and a relationship between retraction and alveolar bone thickness in the midroot area. In the angular direction, there was no significant difference and relationship; however, there was a significant difference in the labial crestal in the tipping group. In the torque group, the difference in bone thickness occurred in the crestal and apical palatal areas. Conclusion: The retraction and the type of tooth movement difference influence the alveolar bone thickness.

Effect of force direction and masticatory force towards orthodontic tooth movement in rats

“…PD5M was the same as on day 10 in both groups with and without mastication, confirming the direction factor of the palatal spring type against the palatal bone's thickness to be the cause. 17 In the same experiment, the osteoblast was not decreased from day 5 to day 10, but the osteoclast number did. The situation of the current experiment was simulant to the OTM, which was not decreased from day 5 to day 10.…”

“…10 The OTM group distance was significantly greater in the labial than in palatal coil spring types, suggesting that the palatal coil force moves the incisor to the distal and palatal direction against wider palatal cortical bone than the labial spring against the thinner distal cortical alveolar bone. 17 Some bite raisers recently used for opening the bite freed the teeth from mastication force and unlocking the bite. Bite raisers treat special cases of malocclusion that impact the three planes of space, opening the occlusion for transverse or anteroposterior correction, preventing unwanted movement of certain teeth, and preventing function switching (due to premature contact).…”

Bone Remodeling of Maxilla after Retraction of Incisors during Orthodontic Treatment with Extraction of Premolars Based on CBCT Study: A Systematic Review

“…In this situation, the tooth violates the bone boundary, remaining partially beyond its reach. The morphology of periodontal tissues, differences in bone density, inclination and position of teeth, and direction and magnitude of orthodontic force determine the type of bone reaction [ 4 , 5 , 6 , 7 ].…”