Browsing by Subject "Tooth Movement"

Now showing 1 - 5 of 5
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    Effects of vibration forces on maxillary expansion and orthodontic tooth movement
    (2015) Aldosari, Mohammad Abdullah M.; Liu, Sean Shih-Yao; Chen, Jie; Katona, Thomas R.; Ghoneima, Ahmed A. M.; Chu, Tien-Min Gabriel
    Vibration forces (VF) have been shown to alter the formative and resorptive activities of bone. Studies have investigated the use of VF in applications such as the treatment of osteoporosis, bone fracture healing and implant osteointegration with favorable results. In dentistry, orthodontic tooth movement and maxillary suture expansion are common procedures typically requiring prolonged treatment durations with high relapse rates. We hypothesized that local, intermittent VF applications can enhance bone formation during rapid maxillary expansion and accelerate orthodontic tooth movement. Moreover, we also investigated expression of periostin/OSF-2, an adhesion molecule implicated in the formation of bone during maxillary suture expansion. Our results showed that intermittent VF significantly increased bone volume density of the expended palatal bone but limited the amount of palatal expansion and mineral apposition rate at the suture margins. Also, intermittent VF forces did not show statistically significant acceleration of orthodontic tooth movement but significantly enhanced bone volume density of the interradicular bone after tooth movement. Maxillary expansion was also shown to induce the expression of periostin which was proportional to the magnitude of the expansion force with increased bone mineral deposition.
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    Hounsfield unit change in root and alveolar bone during canine retraction
    (Elsevier, 2015-04) Jiang, Feifei; Liu, Sean S.-Y.; Xia, Zeyang; Li, Shuning; Chen, Jie; Kula, Katherine S.; Eckert, George; Department of Orthodontics and Oral Facial Genetics, IU School of Dentistry
    INTRODUCTION: The objective of this study was to determine the Hounsfield unit (HU) changes in the alveolar bone and root surfaces during controlled canine retractions. METHODS: Eighteen maxillary canine retraction patients were selected for this split-mouth design clinical trial. The canines in each patient were randomly assigned to receive either translation or controlled tipping treatment. Pretreatment and posttreatment cone-beam computed tomography scans of each patient were used to determine tooth movement direction and HU changes. The alveolar bone and root surface were divided into 108 divisions, respectively. The HUs in each division were measured. Mixed-model analysis of variance was applied to test the HU change distribution at the P <0.05 significance level. RESULTS: The HU changes varied with the directions relative to the canine movement. The HU reductions occurred at the root surfaces. Larger reductions occurred in the divisions that were perpendicular to the moving direction. However, HUs decreased in the alveolar bone in the moving direction. The highest HU reduction was at the coronal level. CONCLUSIONS: HU reduction occurs on the root surface in the direction perpendicular to tooth movement and in the alveolar bone in the direction of tooth movement when a canine is retracted.
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    Mechanical environment change in root, periodontal ligament, and alveolar bone in response to two canine retraction treatment strategies
    (Wiley Blackwell (Blackwell Publishing), 2015-04) Jiang, F.; Xia, Z.; Li, S.; Eckert, G.; Chen, J.; Department of Engineering Technology, School of Engineering and Technology
    OBJECTIVE: To investigate the initial mechanical environment (ME) changes in root surface, periodontal ligament (PDL), and alveolar bone due to two treatment strategies, low or high moment-to-force ratio (M/F). SETTING AND SAMPLE POPULATION: Indiana University-Purdue University Indianapolis. Eighteen patients who underwent maxillary bilateral canine retraction. MATERIAL AND METHOD: Finite element models of the maxillary canines from the patients were built based on their cone beam computed tomography scans. For each patient, the canine on one side had a specially designed T-loop spring with the M/F higher than the other side. Four stress invariants (1st principal/dilatational/3rd principal/von Mises stress) in the tissues were calculated. The stresses were compared with the bone mineral density (BMD) changes reported previously for linking the ME change to bone modeling/remodeling activities. The correlation was tested by the mixed-model anova. RESULTS: The alveolar bone in the direction of tooth movement is primarily in tension, while the PDL is in compression; the stresses in the opposite direction have a reversed pattern. The M/F primarily affects the stress in root. Three stress invariants (1st principal/3rd principal/dilatational stress) in the tooth movement direction have moderate correlations with BMD loss. CONCLUSIONS: The stress invariants may be used to characterize what the osteocytes sense when ME changes. Their distributions in the tissues are significantly different, meaning the cells experience different stimuli. The higher bone activities along the direction of tooth movement may be related to the initial volumetric increase and decrease in the alveolar bone.
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    Three-dimensional canine displacement patterns in response to translation and controlled tipping retraction strategies
    (The Angle Orthodontist, 2015-01) Li, Shuning; Xia, Zeyang; Liu, Sean Shih-Yao; Eckert, George; Chen, Jie; Department of Mechanical Engineering, School of Engineering and Technology
    OBJECTIVE: To validate whether applying a well-defined initial three-dimensional (3D) load can create consistently expected tooth movement in patients. MATERIALS AND METHODS: Twenty-one patients who needed bilateral canine retraction to close extraction space were selected for this split-mouth clinical trial. After initial alignment and leveling, two canines in each patient were randomly assigned to receive either translation (TR) or controlled tipping (CT) load. The load was delivered by segmental T-loops designed to give specific initial moment/force ratios to the canines in each treatment interval (TI), verified with an orthodontic force tester. Maxillary dental casts were made before canine retraction and after each TI. The casts were digitized with a 3D laser scanner. The digital models were superimposed on the palatal rugae region. The 3D canine displacements and the displacement patterns in terms of TR, CT, and torque were calculated for each TI. RESULTS: The method can reliably detect a TR displacement greater than 0.3 mm and a rotation greater than 1.5°. Ninety-two TIs had displacements that were greater than 0.3 mm and were used for further analysis. Most displacements were oriented within ±45° from the distal direction. The displacement pattern in terms of TR or CT was not uniquely controlled by the initial moment/force ratio. CONCLUSIONS: The initial load system is not the only key factor controlling tooth movement. Using a segmental T-loop with a well-controlled load system, large variations in canine displacement can be expected clinically.
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    Three-dimensional image analysis for quantification of tooth movements and landmark changes
    (2013-12-11) Li, Shuning; Chen, Jie; Christopher, Lauren; Bajaj, Anil K.; Katona, Thomas R.; Adams, Douglas E.; Anderson, David C. (David Carleton), 1948-
    Quantification of treatment outcomes (tooth displacement and bony changes) is the key to advance orthodontic research and improve clinical practices. Traditionally, treatment outcome were quantified by using two-dimensional (2D) cephalometric analysis. However, there are problems inherent in 2D analysis, such as tracing errors and inability to detect side-effects. Thus, a reliable three-dimensional (3D) image analysis method for treatment outcome quantification is of high interest. Systematic 3D image analysis methods were developed for digital dental cast models and Cone-Beam Computed Tomography (CBCT) models. A typical analysis procedure includes image reconstruction, landmarks identification, coordinate system setup, superimposition, and displacement or change calculation. The specified procedures for maxillary teeth displacements and anatomical landmarks movements were presented and validated. The validation results showed that these procedures were accurate and reliable enough for clinical applications. The 3D methods were first applied to a human canine retraction clinical study. The purposes of this study were to quantify canines and anchorage tooth movements, and to compare two commonly used canine retraction strategies, controlled tipping and translation. The canine results showed that (1) canine movements were linear with time; (2) the initial load system was not the only factor that controlled the canine movement pattern; and (3) control tipping was significantly faster than translation. The anchorage tooth results showed that (1) anchorage losses occurred even with transpalatal arch (TPA); (2) there was no significant difference in anchorage loss between the two treatment strategies; and (3) compared with removable TPA, fixed TPA appliance can significantly reduce the amount of anchorage loss in the mesial-distal direction. The second clinical application for the 3D methods was a mandibular growth clinical trial. The purposes of this study were to quantify skeletal landmark movements, and compare two widely used appliances, Herbst and MARA. The results showed that (1) the Herbst appliance caused mandibular forward movement with backward rotation; and (2) the treatment effects had no significant differences by using either Herbst or MARA appliances. The two clinical applications validated the methods developed in this study to quantify orthodontic treatment outcomes. They also demonstrated the benefits of using the 3D methods to quantify orthodontic treatment outcomes and to test fundamental hypotheses. These 3D methods can easily be extended to other clinical cases. This study will benefit orthodontic patients, clinicians and researchers.