فهرست مطالب

Iranian Journal of Orthodontics
Volume:9 Issue: 1, Mar 2014

  • تاریخ انتشار: 1394/10/23
  • تعداد عناوین: 8
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  • Massoud Seifi, Negin, Sadat Matini* Page 1
    Aim
    The purpose of the present study was to systematically review the literature on the success and failure of the miniscrews.
    Materials And Methods
    Titles and abstracts in Medline Databases (PubMed) were screened by 2 reviewers. First result contains 273 articles, after search filters they have reached to 9 articles. All articles were discussed by 2 reviewers and disagreements were solved.
    Results
    The total success rate were available in all 9 studies and ranged from 70.3% to 96%. The number of treated patients were ranged from 15 to 141and also the number of miniscrews ranged from 44 to 260. The success and failure rates of miniscrews in these 9 studies had no significant correlation with gender. Statistic methods are different among these clinical trials.
    Conclusion
    It seems that weak consensus exist between bulk of data obtained from different clinical trials. Gender has been mentioned as a predisposing factor for success/failure rate and some article reported more success for male, some for female, and some no difference. Immediate loading has more success rate according to some investigations but many investigators suggest a healing period and delayed loading. Diameter and length of miniscrews and their dispersion factor is another source of inconsistency among authors. Diameters start from (in millimeter) 1.2, 1.3, 1.6-1.8 to 2 mm and length starts from (in millimeter) 5, 6,7,8 to 10 mm and different success rate is reported for these parameters. Even success/failure rate is described differently among clinicians and it start from stability during first one week, extends to six month and two year. In addition, some authors believe that because of the pool of subjects (large sample with important elements) in retrospective studies, appropriate statistics are “Kaplan-Meier survival curves” based on rigorous clinical success\failure criteria instead of success\failure rate.
    Keywords: Miniscrews, Mini, screw, Miniscrew, Success, Miniscrew, failure, Orthodontic Anchorage procedure
  • S. Naghinejad Ahmadi, M. Kochoei Pages 8-12
    Aim
    Orthodontic mini-implants have been incorporated into orthodontic treatment modalities. Adequate bone at mini-implant placement site can influence the success or failure of anchorage. The aim of the present study was to determine the thickness of bone in the maxillary mid-palatal area at predetermined points for the placement of orthodontic mini-implants using Cone Beam CT technique in order to evaluate the relationship of these values with the facial height.
    Materials And Methods
    A total of 161 patients, consisting of males (39.32%) and females (60.86%), were evaluated in the present study; 38% of the subjects had normal facial height, 29% had short face and 33% had long face. In order to determine which patient belonged to which facial height category, i.e. normal, long or short, two angular and linear evaluations were used: the angle between S-N and Go-Me lines and the S-Go/N-Me ratio. Twenty points were evaluated in all the samples. First the incisive foramen was located. The para-coronal cross-sections were prepared at distances of 4, 8, 16 and 24 mm from the distal wall of the incisive foramen and on each cross-section the mid-sagittal and para-sagittal areas were determined bilaterally at 3- and 6-mm distances (a total of 5 points). The thicknesses of the bone were determined at the predetermined points.
    Results
    Statistical analysis did not show significant differences between three different facial height groups at none of the 20 points.
    Conclusion
    The present study did not find any relationship between palatal bone thickness and facial height. Further studies with larger sample size are necessary to evaluate the relationship between the thickness of bone and facial height.
    Keywords: Anchorage, Cone beam CT, Facial height, Cortical Bone thickness
  • Mk. Soltani, A. Miresmaeili, B. Javanshir*, M. Akbarzadeh Pages 13-20
    Background and Aim
    functional appliances with various designs have been introduced in the treatment of Class II malocclusions. The aim of this study was to evaluate dentoskeletal effects of a modified bionator (FA) and Twin Block (TB) functional appliance in treatment of skeletal Class II malocclusion.Method and material: in this retrospective study 30 treated cl II patients with overjet greater than 4 mm have been selected from each of two private offices. in each office either FA or TB were used. Pre-treatment and post-treatment lateral cephalograms were digitized and traced with Dolphin Imaging software. ANCOVA and paired T test were used for analysis with SPSS software (19).
    Results
    FA group consisted of 17 girls and 13 boys(mean age: 9.53± 1.1),TB group consisted of 12 boys and 18 girls(mean age: 10.26 ±.944). ANB angle and overjet were reduced significantly in both groups.(p=.000) Mandibular body length demonstrated a significant increase in both groups.(3.06±4.98mm with TB and 3.03±5.52mm with FA).In Both appliances significant retrusion of upper lip occurred as a result of decrease in overjet (TB=002,FA=.000).No statistical significant difference were found between two appliances.
    Conclusions
    Treatment with both appliances resulted in correction of Class II discrepancy, reduction of overjet, and retrusion of upper lip. No significant dento-skeletal differences were observed between the 2 appliances
    Keywords: angle cl II malocclusion, activator appliances, cephalometry, treatment
  • A. V.Jumle, N. Toshniwal Pages 21-25
    Aim
    The aim of this study was to intercept the Class II Div 1 malocclusion with 3 dimensional defects early in mixed dentition to reduce its severity, so to avoid the psychological trauma, in this poor non-compliant patient, which would also be cost effective.
    Method
    A combination appliance, which would consider all 3 dimension, be cost effective and which would not depend on patient for compliance was a need for this patient. So an innovative approach of using a maxillary expansion plate with the incline plate as that of twin block but which can be cemented to the arch and prism shaped composite blocks as that of Planas Direct Tract on the mandibular second deciduous molar was designed. As soon as the appliance was bonded, profile was improved.Results and
    Conclusion
    At the end of 8 months of active treatment, there was improvement in transverse, sagittal and vertical dimension with the satisfaction of the patient and the parent. The fabricated combination appliance, proved successful for intercepting the condition, satisfying the patient and parent by improving psychological condition along with the Class II condition. It was decided to name the appliance as 3D RDC CORRECTOR [3 dimensional (institution name) corrector].
  • N. Hosseini, H. Azadikhah, S. Yassaie, M. Tayyebi Pages 26-30
    Background And Aim
    cross bite is an Abnormal relationship between one or more teeth and their corresponding antagonist tooth so that the buccolingual or labiolingual relationship is opposite. Given the high prevalence and impact of these disorders, diagnosis and early treatment of this problem is very important. The aim of this study is to determine the prevalence of anterior and posterior cross bite for girls and boys who were 7-10 years old in Yazd,Iran.
    Materials And Methods
    This cross-sectional study on 400 students aged 7-10 was carried out using clinical examination. Examinations were performed by the dentist and the presence or absence of crossbite and occlusal relationship was evaluated in the mixed dentition.
    Results
    The prevalence of anterior cross bite is 11%, 12.9% of girls and 9% of boys and prevalence of posterior cross bite was 3.5%, 4.5% in girls and 2.5% in boys. prevalence of anterior cross-bite at age 9 was 11.9% and posterior cross bite at age 10 was 7.1% which are the highest rates reported. In mouth breathing children 35.7 % and 21.4%, had anterior and posterior cross bite respectively.The anterior and posterior cross bite was more in Class II malocclusion than any other malocclusion.Among the cases investigated,mouth breathing and malocclusion have correlation with crossbites.
    Conclusion
    Given the prevalence of anterior and posterior cross bite, mothers should be awared on the prevention and control of these disorders and also periodic examinations of children To prevent complications in future.
    Keywords: crossbite, malocclusion, child
  • M. Kachoie, B. Divband, M. Khatamian, A. Nourian Pages 31-36
    Introduction
    NiTi wires which are considered the ideal alloys used during the alignment and leveling stage of comprehensive orthodontic treatment exhibit very high frictional resistance. Therefore, overcoming such resistance to sliding results in a rapid tooth movement and proper anchorage control. Recently, coating the wires with nanoparticles has been introduced to decrease resistance to sliding. The aim of this invitro study was to evaluate effect of ZnO nanoparticles on resistance to sliding of nickel titanium orthodontic wires.
    Materials And Methods
    40 straight pieces of 0.016-inch NiTi wires were evaluated in two groups with and without spherical ZnO nanoparticle coating, along with 40 standard system 0.018 stainless steel brackets. ZnO nanoparticles were deposited on NiTi wires and analyzed by SEM. A universal testing machine was used to determine friction between the wires and brackets at an angle of 5°. Student’s t-test were used for data analysis.
    Results
    The SEM results confirmed the homogeneous deposition of ZnO nanoparticles on NiTi wires. At 5º angle between the wires and brackets the means of frictional forces were 1.2475±0.13 and 1.5075±0.12 N with and without ZnO nanoparticle deposits on the wires, respectively, revealing a significant decrease of 17.24% in frictional forces in coated wires (P<0.001).
    Conclusion
    Based on the results of this study, ZnO nanoparticle coating reduces the resistance to sliding of nickel titanium orthodontic wires.
    Keywords: ZnO nanoparticles, resistance to sliding, NiTi wires, orthodontic brackets
  • T. Hosseinzadeh Nik, E. Sadat Emdadian Razavi, A. Modarresi, M. Mollaei Pages 37-42
    Introduction
    A possible treatment option for non-growing patients with vertical maxillary excess (VME), is superior repositioning of maxilla with or without mandibular surgery. After maxillary impaction, mandible rotates around a center. A common assumption at the time of cephalometric prediction, is taking condyle as an unchangeable center of rotation. Any error in determination of center of mandibular autorotation (CMA) may lead to improper jaw positioning and unaesthetic results.
    Materials And Methods
    In this study, before and after cephalometric radiographs from fourteen orthognathic patients with maxillary impaction were evaluated.
    Results
    showed that center of mandibular autorotation are not similar in different patients, partly because of individualized craniofacial morphology. Therefore, precise determination of center of mandibular autorotation is necessary for obtaining ideal results.
    Keywords: Le Fort I, Superior repositioning, mandibular autorotation, center of rotation
  • S. Yassaei, F. Eslami, R. Ghafouri Fard Pages 43-49
    Aim
    Considering the importance of stability on the orthodontic treatment outcomes, the instability may cause dentoskeletal and soft tissue changes in patients after the treatment. The aim of this study was to evaluate dentoskeletal and facial soft tissue relapse in class II patients whom have been treated with functional appliances.
    Materials and Methods
    23 patients with Class II Division 1 malocclusion who had received treatment with Farmand functional appliance and had at least two years of post treatment follow up, were evaluated using cephalometric analysis for dentoskeletal and soft tissue changes. The lateral cephalometric radiographs of the patients immediately after the treatment (T1) and two years follow up (T2) were traced and statistical analysis was performed to obtain the amount of occurred relapse between T1 and T2.
    Results
    The mean decrease of ANB angle between T1 and T2 was 0.73 º, which was not statistically significant. Overall, the mean changes of skeletal and dental variables (FMA, GOGN-SN, U1 to SN, U1 to FH and IMPA) in T1 and T2 were not statistically significant. For the soft tissue variables, the mean increase of the nasolabial and mentolabial angle in T1 and T2 were not significant. The mean changes of Z and H angles in T1 and T2 were 0.53º and 0.63 º, which were not statistically significant.
    Conclusion
    Dentoskeletal and soft tissue facial changes that occurred during treatment with Farmand functional appliance remained stable at least 2 years after treatment.
    Keywords: Functional appliance, class II divison 1, Malocclusion, relapse