IRANIAN JOURNAL OF ORTHODONTICS
Year:2018 | Volume:13 | Issue:2|Papers Count:8

Background: Splinting anterior teeth is a way to fix them after orthodontics treatments. Occlusal trauma from functional or parafunctional forces can cause stress increase and movements of teeth especially while having bone loss. Methods: Six anterior teeth with different bone levels were designed in SolidWorks (2010), the models were then transferred to ANSYSWorkbench 12. 1. The models were loaded with 187 N force on the incisal edges of two incisors. Results: Stress on canine was 0. 45 MPa in normal bone height and increased to 0. 60 MPa in five millimeters of anterior teeth bone loss. Labial displacement was less in normal alveolar bone height while it was increased in all those teeth with five millimeter of bone loss. Conclusions: Splinting distribute the forces between teeth and the stress production on canine increase while it splinted with low level bone incisors. Anterior teeth also showed tipping movements in reply to increased forces.

Background: Evaluating patient’ s soft tissue profile is one of the most imperative components for orthodontic diagnosis and treatment planning. Objectives: The purpose of this study was to determine the soft-tissue cephalometric standards for Yemeni adults. Methods: The material composed of the lateral cephalometric radiographs of one hundred ninety-four Yemeni adults (105 females and 89 males) aged between 18 and 25 years, selected from dental students in Sana’ a University. Each film was traced and analyzed using variable linear and angular measurement. Results: Statistical significant differences were reported among genders in H-angle and N’-Pr-Pg’ , whereas, N’-Sn-Pg’ , nasolabial and mentolabial angles showed no significant differences. Conclusions: The results of Yemeni cephalometric analyses showed ethnic differences in soft tissue findings. Considering the soft tissues pattern of each population will guarantee improved results of treatment to establish the best possible facial harmony.

Background: The purpose of the present study was to evaluate the influence of asthma on the degree of apical root resorption in patients treated orthodontically. Methods: Sample comprised 683 patients treated orthodontically; 240 with asthma and 443 who did not present any kind of respiratory allergy or asthma. The Levander and Malmgren score was used for the evaluation of the degree of root resorption. This evaluation was performed in the initial and final periapical radiographs of the maxillary and mandibular incisors of all patients in the sample. Then, the sample was divided as follows: Group 1: 614 patients presenting mild or no root resorption with scores 0, 1 and 2, with mean initial age of 14. 37 years, final age of 16. 44 years and treatment time of 2. 07 years; group 2: 69 patients who had moderate to severe root resorption with scores 3 and 4, with mean initial age of 15. 09 years, final age of 17. 81 years and treatment time of 2. 72 years. Results: The results revealed that asthma was not a statistically significant factor for severe root resorption. The group with severe root resorption showed higher initial and final age, and longer treatment time than the group with mild root resorption. In addition, performing extractions is a risk factor for the occurrence of severe root resorption. Conclusions: Asthma is not a risk factor for the occurrence of severe root resorption after orthodontic treatment.

Background: To evaluate orthodontic treatment need (OTN) in a juvenile populace, utilizing the Index of Orthodontic Treatment Need (IOTN), including sexual orientation contrasts evaluation. Methods: The example involved 2250 young people, 13. 1-17. 4 years of age (mean age, 14 years and 6 months). The examinations were done on the study models and all encompassing radiographs taken from every subject. The dental health (DHC) and aesthetic (AC) segments of the IOTN were applied as an evaluation measure of the requirement for orthodontic treatment. The agreement (kappa measurements) was ascertained to examine the understanding between the DHC and the AC of the IOTN. Results: Utilizing the DHC of the IOTN, the extent of subjects assessed to have an incredible or extremely extraordinary treatment need was 28. 7%, and 16. 7% were in need (grades 8-10) as indicated by the AC (IOTN). No sexual orientation contrasts were noted, with the exception of no need class of the IOTN (more successive in young men) as per the DHC (chi-square: 6. 83, df: 1, P = 0. 01). There was a moderate agreement between the DHC and the AC of the IOTN (kappa = 0. 49, 95% CI, 0. 47-0. 63). Conclusions: Using the IOTN, approximately a third of theadolescent school children werebeing found to be qualified for treatment in open programs.

Objectives: Aim of this study was to do a comparative post-treatment assessment, using three superimposition methods (Ricketts, Pancherz and Centrographic), in patients with Angle’ s Class II Division 1 malocclusion and functional retrusion of mandible following twin block appliance therapy. Methods: In this retrospective cross sectional study, pre and post-treatment lateral cephalometric radiographs of 33 cases were analyzed and compared using Ricketts, Pancherz and Centrographic superimpositionmethods. Changes were evaluated quantitatively for all three methods using a reference grid. The anteroposterior position of upper and lower centroids with respect to the centroid plane was evaluated. Results: Paired samples t-tests and intraclass correlation coefficient revealed excellent reliability of Ricketts, Pancherz and Centrographic superimposition techniques for all parameters. An advancement of 4. 14 + 2. 24 and 4. 18 + 2. 26 in Pancherz, 4. 30 + 2. 14 and 4. 38 + 2. 18 in Ricketts and 4. 36 + 2. 19 and 4. 50 + 2. 19 in Centrographic superimposition methods was shown by point B and pogonion respectively. The observed advancement of Point B and restriction of mesial movement of upper first molar (U6) was statistically significant for Centrographic method as compared to Pancherz. Advancement of lower centroid was seen in all cases with 72. 7% in level with centroid plane and 24. 2% within 1mm of it. Conclusions: All three superimposition methods (Ricketts, Pancherz and Centrographic) proved equally reliable in assessing treatment changes following twin block therapy. Forward movement of lower centroid was observed in 100% of the cases indicating true mandibular advancement following twin block appliance therapy in Skeletal Class II Division 1 malocclusions.

Background: Rapid maxillary expansion (RME) is an important method for correcting maxillary transverse deficiency. Objectives: The aim of this study was to assess the variations of the palatal plane in the anteroposterior and vertical directions after RME observed under cone-beam computed tomography. Methods: The images using the cone-beam computed tomography were obtained from the skull of 15 patients (10 males, 5 females) with ages from 7 to 14 years, at the specialization course in orthodontics of the School of Dentistry at UFBA before (T0) and after (T1) RME using the Haas-type expander. The sagittal slices were obtained with Dolphin imaging program, premium version 11. 0, in order to visualize the most anterior and posterior extremities of the maxillary bone and the following points: Sella (S), nasion (N), anterior nasal spine (ANS) and posterior nasal spine (PNS). The distances between points S and PNS (L1) and between N and ANS (L2) and the angles formed by the intersection of line SN with the palatal plane (angle 1) and line SN with line N-ANS (angle 2) were measured. Results: The values obtained were statistically analyzed using Students t-test. At the time intervals assessed, no statistically significant difference was found in the linear measurements L1 and L2 (P = 0. 296 and P = 0. 674, respectively). No statistical significance was found when assessing angles 1 and 2 (P = 0. 673 and P = 0. 589, respectively). Conclusions: RME using the Haas-type expander does not cause any alterations in the vertical or sagittal position of the maxilla.

Introduction: Macrodontia or Megadontia or Megalodontia is simple enlargement of all tooth structures. Most of the literature regarding this condition belongs to 1970’ s and 80’ s and very recent clinical case reports in different ethinic groups are lacking. The etiology of unilateral versus bilateral macrodontia of premolars is unexplained till date. The prevalence of macrodontia of premolars in mandible is higher than in the maxilla. Isolated macrodontia of second premolars has beenknownbymanysynonyms like “ Macrodont molariform premolars” and “ Megadonts” . Case Presentation: A 16 year old male adolescence patient had reported with a complain of forwardly placed upper front teeth. Routine clinical examination revealed a uniquely-appearing second premolar on the right side of the mandibular arch. The surface area of the crown was two to three times greater than that of normal premolars. There was crowding of the lower anterior teeth with labial placement of lower canines. The intraoral periapical radiograph showed a huge premolar tooth with a single, short, stunted and tapering root. The Model analysis favours expansion of the mandibular arch and extraction of the premolar teeth in maxillary arch for contraction of the arch. Conclusions: For proper space management, any developmental anamoly involving the shape of the tooth such as a macro premolar or an erupted odontome has to be extracted as early as possible, as part of the orthodontic treatment plan and fixed appliance therapy initiated. Treatment of macropremolars is a challenging task for the orthodontist, as it requires accurate space analysis and space management.

Large variation exists amongst patients with regards to treatment outcomes following functional appliance treatment in growing children. Various factors have been assessed with regard to this variation, but evidence is scarce. Recent studies suggest that the initial condition of the masticatory muscles may be one of the factors that influences treatment and post-treatment functional appliance outcomes. Children with weaker masticatory muscles show greater dentoalveolar change, as witnessed by incisor compensation and molar movement. Following functional appliance treatment, children who show greater dentoalveolar treatment change may also be those with a more likely post-treatment sagittal relapse. The gonial angle may also be a variable determining treatment outcomes with functional appliances in that more incisor compensation and a greater likelihood for relapse is evident in those with a more open gonial angle. The gonial process is the site of muscle attachment for the masseter and median pterygoid muscles, and the thickness and force of these muscles can have an effect on the process and its contribution to mandibular morphology. By extrapolation, cephalometric analysis of the gonial angle can perhaps provide insight into the amount of incisor proclination expected to be observed during and after functional appliance treatment.