Mesial migration effect on root morphology of mandibular third molars.
(2006)
Journal - The Angle orthodontist (United States )
Abstract :
OBJECTIVE: To test the hypothesis that there is a relationship between forward mandibular third molar migration and root curvature of the mandibular third molars. MATERIALS AND METHODS: The study is comprised of 64 patients who had a history of unilateral mandibular first molar extraction before 16 years of age with no other missing teeth or prosthetic restorations in the mandible. The extraction space was fully or partly closed. The mean remaining space was 1.1 +/- 0.41 mm. The root angles for the mesial and distal roots of the mandibular third molars were measured on the panoramic radiographs by calculating the differences between the angle formed by the long axis drawn perpendicular to the occlusal plane of the crown of mandibular third molar and the central line of the lower one ninth of the root through the root apex. The differences between the extracted and nonextracted sides for mesial and distal roots were analyzed using a paired sample t-test. RESULTS: Both mesial and distal roots were approximately 8 degrees more vertical on the extraction sides than on the nonextraction sides. The differences were statistically significant. CONCLUSION: Mesial tooth migration of mandibular third molars reduces the amount of root curvature developing on this tooth.
| ISSN : | 0003-3219 |
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| Mesh Heading : | Adolescent Adult Female Humans Male Mandible Molar Molar, Third Odontometry Radiography, Panoramic Statistics, Nonparametric Tooth Extraction Tooth Movement Tooth Root surgery methods radiography |
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| Mesh Heading Relevant : | Mesial Movement of Teeth physiology growth & development |
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Nasal airway changes due to rapid maxillary expansion timing.
(2005)
Journal - The Angle orthodontist (United States )
Abstract :
The purpose of this study was to evaluate the effect of rapid maxillary expansion (RME) on nasal minimum cross-sectional area (MCA) using acoustic rhinometry (AR) in two groups of subjects who were treated before and after the pubertal growth spurt. The sample consisted of 29 patients with maxillary constriction and a control sample of 15 subjects. Both samples were divided into two groups according to individual skeletal maturation as assessed by the cervical vertebral maturation (CVM) method. Group I T (early-treated) consisted of 16 patients (eight girls and eight boys). Group I C (early-control) consisted of eight patients, and both groups had not reached the pubertal peak (CVM Stage 1-3). Group II T (late-treated) consisted of 13 patients (eight girls and five boys). Group II C (late-control) consisted of seven patients, and both groups were at a stage during or after the pubertal peak (CVM Stage 4-6). AR records were obtained for each treated subject before treatment (T1), after expansion (T2), and immediately after a three-month retention period (T3); only T1 and T3 records were obtained for controls. The overall increase in MCA was significantly greater in the early- and late-treated groups (group I T, group II T) as compared with the early and late controls. (group I C, group II C) (P < .05). The results of the present study suggest that even the overall (T1-T3) increase for MCA in group I T is greater (0.34 mm) than the increase for MCA in group II T (0.19 mm), but the difference was not significant (P > .05).
| ISSN : | 0003-3219 |
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| Mesh Heading : | Adolescent Age Factors Airway Resistance Cervical Vertebrae Child Female Humans Male Malocclusion Maxillofacial Development Nasal Cavity Nasal Obstruction Rhinometry, Acoustic Statistics, Nonparametric Treatment Outcome growth & development complications physiology etiology |
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| Mesh Heading Relevant : | Palatal Expansion Technique therapy anatomy & histology therapy |
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