فهرست مطالب

  • Volume:11 Issue: 1, 2016
  • تاریخ انتشار: 1395/05/11
  • تعداد عناوین: 8
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  • Zahra Dalili Kajan, Navid Karimi Nasab, Jalil Khademi, Faegheh Gholinia, Zeinab Taheri, Mona Hajighadimi Page 1
    Background
    Proper defining of normal landmarks in lateral cephalograms is important for establishing proper orthodontic treatment plan.
    Objectives
    To evaluate the agreement of dental students to identify normal landmarks (NLs) in digital lateral cephalograms and cone beam computed tomography (CBCT) images.
    Patients and
    Methods
    In this study, lateral cephalograms and CBCT images of 11 orthodontic patients were selected. Three fourth-year dental students were asked to identify 19 NLs after calibrating digital lateral cephalograms and 3D CBCT images. Then, the distances of each landmark from the superior and anterior edges of the images were measured for each observer.
    Results
    The observers’ errors fell within a range of -1.03 to 2.74 in two-dimensional cephalometry and a range of -0.88 to 2.31 in 3D CBCT, showing a 95% limit of agreement. According to the intraclass correlation coefficient (ICC) comparison made by our student observers, only 5% of interobserver assessment in CBCT and 20% in lateral cephalometry showed poor reliability. These same observers showed more agreement when identifying NLs on soft tissue as compared to hard tissue structures and also in detecting NLs located in the midsagittal region rather than on lateral sides in both modalities. Their differences in agreement in detecting midsagittal NLs rather than on lateral sides were statistically significant (P = 0.0001).
    Conclusions
    The training of cephalometric tracing in orthodontic course based on 3D skull models and imaginary methods was deemed successful in increasing the ability of dental students to determine the precise location of NLs, even on CBCT images.
    Keywords: Anatomic Landmark, Cephalometry, Cone Beam Computed Tomography
  • Mashallah Khanehmasjedi, Mohammad Ali Naseri, Samaneh Khanehmasjedi Page 2
    Objectives
    The present study was carried out to compare the shear bond strength of metallic brackets bonded with single Bond and Assure bonding agents under dry and saliva contamination conditions.
    Materials And Methods
    A total 60 sound premolar teeth were selected for the purpose of this in vitro study and stainless steel brackets were bonded on enamel surfaces with single bond and assure bonding agents under a dry condition or with salivary contamination. The shear bond strength values of the brackets were measured in a universal testing machine. The adhesive remnant index (ARI) scores were determined after debonding of the brackets under a stereomicroscope. One-way ANOVA was used to analyze bond strength. Two-by-two comparisons were made with post hoc Tukey tests (P
    Results
    The bond strength values of brackets to tooth structure were 9.29 ± 8.56 and 21.25 ± 8.93 MPa with the use of Assure resin bonding agent under saliva contamination and dry conditions, respectively. These values were 10.13 ± 6.69 and 14.09 ± 6.6 MPa, respectively, under the same conditions with the use of single bond adhesive. Contamination with saliva resulted in a significant decrease in the bond strength of brackets to tooth structure with the application of Assure adhesive resin (P
    Conclusions
    Application of single bond and assure bonding agents resulted in adequate bond strength of brackets to tooth structures. Contamination with saliva significantly decreased the bond strength of Assure bonding agent compared to dry conditions.
    Keywords: Shear Bond Strength, Assure Universal Bonding Resin, Single Bond Adhesive Resin
  • Navid Naseri, Pedram Baghaeian, Maryam Javaherimahd, Fatemeh Gorjizadeh Page 3
    Background
    It has been proved that, there's craniofacial asymmetry but much of this skeletal asymmetries are clinically ignorable. This asymmetry may exist in teeth size arranged in right and left sides of human mouth too. Orthodontists should pay attention to bilateral tooth asymmetry in treatment planning stage.
    Objectives
    This study was conducted to demonstrate whether the difference between size of left and right side teeth is actual.
    Materials And Methods
    A total of 200 plaster dental molds were used which were collected from a private practice in Tehran. A caliper with accuracy of 0.01 mm was used for measuring teeth and most teeth were measured twice and the average value was considered as the teeth size. In all cases, the Vernier calipers jaws were moved along the teeth longitudinal axis and the biggest width was measured in the contact point area.
    Results
    In average 83.16% of left and right teeth in upper jaw and 83.66% of left and right teeth in the lower jaw were not symmetrical and teeth in the upper and lower jaws were completely similar 16.84% and 16.34%, respectively.
    Conclusions
    The result of the study showed that nearly 83% of teeth in maxilla and mandible are asymmetric in mesiodistal width. Mandibular second molar and canine showed the highest and lowest bilateral asymmetry respectively.
    Keywords: Asymmetry, Tooth Size, Mesiodistal Width
  • Sidra Butt, Imtiaz Ahmed Page 4
    Background
    The forensic anthropologists have been vastly studied the dimorphism in teeth, hair, pelvis, skull and in bone sizes.
    Objectives
    To investigate the gender dimorphic potential of cephalometric parameters.
    Materials And Methods
    Thirteen angular and twenty-one linear lateral cephalometric measurements were analyzed on randomly selected manual tracings of sixty-nine male and sixty-nine female cephalograms between the ages twenty to fifty years.
    Results
    91.3% males correctly classified in the data, on the basis of discriminant function we made, similarly, 97.1% females were correctly classified in their specific group by the help of this discriminant function. The percentage of skulls correctly classified with this function was 94.2%.
    Conclusions
    94.2% of original grouped cases correctly classified. For higher results extensive research with large sample size and both linear and angular cranial dimorphic traits for gender identification is proposed.
    Keywords: Skull Dimorphism, Dental Radiology, Imaging, Lateral Cephalogram, Discriminant Function, Forensic Dentistry
  • Atefe Saffar Shahroudi Page 5
    Objectives
    The aim of this study was to assess the effects of different orthodontic vertical loop height and design on its force characteristics at different amount of loop activation by means of finite element method (FEM) analysis.
    Materials And Methods
    Four 3D FEM models were designed of double vertical open loop (DVOL) and double vertical helical open loop (DVHOL) each of them in two heights of 6 mm and 7 mm. The loops were modeled in SolidWorks 2006 and then transferred to ANSYS Workbench. The loops were activated in buccolingual direction for 0.1, 0.3, 0.5, 0.7 and 1 mm simulating an activated multi-loop arch wire to align a posterior tooth which is erupted with buccal or lingual inclination. The force delivered at each amount of activation for the four loop designs were measured and compared.
    Results
    The results of this study showed that the minimum amount of force was delivered by double vertical helical open loop with the height of 7 mm at the activation of 0.1 mm which was about 1.06E-01 N. The maximum amount of force was 2.2199 N which was delivered by double vertical open loop with height of 6mm at 1 mm activation. At each amount of activation the value of exerted force followed this order: DVOL 6 mm > DVOL 7 mm > DVHOL 6 mm > DVHOL 7 mm.
    Conclusions
    According to this FEM study, considering its limitations, adding a helix in a double vertical open loop as well as increasing the height of loop can reduce the value of delivered force.
    Keywords: Loop Height, Loop Design, Force, Finite Element Analysis
  • K. Hero Breuning Page 6
    In this review, new developments as has been recently published such as digital dental models, virtual treatment planning, intra oral scanning, merging of the intraoral scan and the CBCT and finally the use of custom orthodontic brackets and computer bend wires will be discussed.
    Keywords: Orthodontics, 3D Imaging, Intra Oral Scanning, CBCT, Digital Planning, SETUP
  • Ahmad Sodagar, Elham Sadat Emadian Razavi, Homa Farhadifard Page 7
    Introduction
    A bilateral scissors-bite is an uncommon malocclusion and its treatment is difficult. At younger age, it can be treated non-surgically.
    Case Presentation
    This case report describes successful treatment of a class II division 2 malocclusion with bilateral scissors-bite by fixed appliance. Treatment was completed with the aid of a modified lingual arch, constricted transpalatal arch and repeated arch coordinations.
    Conclusions
    After treatment, the patient had normal overjet, normal overbite and functional occlusion. Scissors-bite was eliminated. The patient will refer for advancement genioplasty at the proper age for more facial harmony.
    Keywords: Scissors-Bite, Lingual Arch, Fixed Appliance
  • Farhad Sobouti, Fatemeh Namvar, Sepideh Dadgar Page 8
    Context: In recent years, lasers have numerous applications in orthodontics as an important field of dentistry. The purpose of this article is to review some of the major applications of laser in the field of soft tissue management in orthodontics.
    Evidence Acquisition: No single laser wavelength can be used to optimally treat all dental diseases. However, the needs of the orthodontic clinician are unique and selection of the most appropriate laser for orthodontic applications is essential to achieve optimal results.
    Results
    Light emitted from diode lasers is poorly absorbed by dental hard tissues, these lasers can be safely used for soft tissue surgery applications, including gingival recontouring, crown lengthening, removal of hypertrophic tissue and frenectomies close to the enamel, dentine and cement. Considering beam safety, most of the lasers used for medical and dental purposes are in the Class IV category, so it is necessary to take appropriate safety measures.
    Conclusions
    In the near future, with the clarification of laser exposure protocols and a decrease in device cost and, Dental lasers may play an increasingly important role in soft tissue management during orthodontic treatment.
    Keywords: Laser, Orthodontics