Mohsen Shirazi; Armin Soudi; Pedram Baghaeian; Yasamin Farajzadeh Jalali
Abstract
Background: The aim of this study was to investigate the crystal structure of mineral part in the Compact and Cancellous bones in different areas of alveolar bones.
Methods: In this study, 7 alveolar bone samples were prepared from buccal and distal plates of the jaws of three patients, and 4 samples ...
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Background: The aim of this study was to investigate the crystal structure of mineral part in the Compact and Cancellous bones in different areas of alveolar bones.
Methods: In this study, 7 alveolar bone samples were prepared from buccal and distal plates of the jaws of three patients, and 4 samples from Cortical and Cancellous bone of two other patients' palate. After converting all the samples into powder, the samples were examined by using the X-RD method. Diffractogram of 1-7 samples were compared with each other and Diffractogram of 8-11 samples also were compared with each other too. Results: Comparing two corresponding points in the jaws the crystallinity degree in the mandible is higher than the maxilla. In comparison of two corresponding points in the maxilla and mandible degree of crystallinity and the crystalline hydroxyapatite on the right has been more than on the left. The amount of crystalline hydroxyapatite phase in females is more than males and crystallinity degree of this phase in males is more than females, and in younger people, the hydroxyapatite crystalline phase is more than others and crystallinity of this phase in older subjects is higher than others.
Conclusions: Tooth movement, despite the influence of the same forces, is faster on left side than the right side and is faster on maxilla than mandible. Tooth movement is faster in younger people than in older subjects.
Nasrin Farhadian; Amirfarhang Miresmaeili; Vahid Mollabashi
Abstract
Introduction: Complications to force eruption of impacted teeth may arise from several reasons including ankylosis, dilaceration, and/or some barriers in the eruption pathway. Treatment time prolongation without obvious clinical progress gradually decreases the patient compliance. In this paper we present ...
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Introduction: Complications to force eruption of impacted teeth may arise from several reasons including ankylosis, dilaceration, and/or some barriers in the eruption pathway. Treatment time prolongation without obvious clinical progress gradually decreases the patient compliance. In this paper we present a non-conventional method to forced eruption of an impacted maxillary canine.
Case Presentation: A-21-year old girl presented with missing of teeth No 17, 12, 22, 27, 38, 37, 47, 48 and labially impaction of both maxillary canine was prepared for treatment through apically position flap for exposure of the both canines. Using standard edgewise 0.18 appliance and conventional elastic traction the right maxillary canine erupted to its normal position after about 18 months but the other tooth had not responded favorably to this technique. There was no signs of ankylosis, a titanium bone screw was placed in the labial cortical bone and mesial of the malposed canine. A spring is made of 0.017” × 0.025” SS wire with two helixes that delivered about 100 g force and 400 gr.mm activation moment to labial bracket on malposed canine crown. The force exerted on mini implant will be balanced with a force and moment on malposed tooth very similar to type IV Burston classification. After about 5 months the tooth had reached to its final occlusal position.
Conclusions: The appliance used for this patient brought the impacted canine into the arch without any more force on the neighbor teeth. Two point contact of the spring arm by bending the wire over the head of the mini implant made it possible to apply buccolingual crown torque.
Esfandiar Akhavan Niaki; Javad Chalipa; Ahmad Reza Dehpour; M Khalili; Arezoo Ghahari
Abstract
Aim: The appearance of osteoclasts is the first step in orthodontic tooth movement. During orthodontic force application, the periodontal ligament (PDL) undergoes hyalinization. This tissue damage prevents the tooth from moving until the adjacent bone and necrotic tissue are removed by osteoclasts. There ...
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Aim: The appearance of osteoclasts is the first step in orthodontic tooth movement. During orthodontic force application, the periodontal ligament (PDL) undergoes hyalinization. This tissue damage prevents the tooth from moving until the adjacent bone and necrotic tissue are removed by osteoclasts. There is a range of forces that produce the maximum rate of tooth movement. The purpose of this study was to compare the effect of different orthodontic forces on osteoclast numbers.Materials and Methods: Forty rats were randomly divided to 4 experimental groups. Appliance exerted 25gr in light, 40gr in moderate and 60gr in heavy group. There was not any appliance in control group. Animals were sacrified after 14 days and tissue samples were prepared. The mesial and distal surfaces of first upper molar and adjacent alveolar bone were studied. Osteoclast numbers, cementoclast numbers, root length, root resorption, depth and length of resorptive cavities, PDL. width in coronal-middle-apical, apical and coronal inflammation, bone resorption, necrotic bone and tooth movement were evaluated. Mesial and distal surfaces were also compared.Results: In menial osteoclast numbers, depth of resorptive cavities, bone resorption, necrotic bone, PDL width and in distal apical inflammation, bone resorption, necrotic bone and PDL width were significant. Tooth movement was significantly different between all groups. (P<0.05)Conclusion: This data suggest that osteoclasts numbers are increased when force is increased. The magnitude of the orthodontic force is believed to be an important factor, not only for the magnitude of the tooth movement but also for any tissue damage.
