ABSTRACT
Statement of the Problem: Stainless steel brackets release metallic ions following the process of corrosion in the oral environment. These released ions have potential adverse effects on health, friction between wire and bracket, staining, strength of brackets. Choosing a bracket with favorable corrosive properties; therefore, should be a goal of every practitioner
Purpose: The goal of this study is to compare the amount of corrosion among five different brands of brackets using inductively coupled plasma [ICP] mass spectrometry
Materials and Method: Five different brands of brackets [Dentaurum, 3M, Ortho Organizer, Cobas and O.R.G] were chosen and ten brackets were selected from each brand. A piece of stainless steel wire was ligated to each bracket. The bracket-archwire complex was then immersed in artificial saliva. Subsequently, the samples were analyzed using an ICP device and the levels of iron, chromium, nickel, and manganese ions were measured
Results: The findings of this study demonstrated that iron was released the most from the tested brackets, followed by nickel. We also found that the Cobas bracket had the most ion release among the tested brackets [p< 0.05], while Ortho Organizer and ORG performed favorably. There was no significant difference between Dentaurum and 3M [p> 0.05]
Conclusion: Based on the results, Ortho Organizer and ORG brackets are suggested in terms of resistance to corrosion
ABSTRACT
Objective: Adaptation of the pharyngeal airway space does occur after different surgical strategies of class III patients including mandibular setback, maxillary advancement and bimaxillary surgery. The aim of this study is to conduct a detailed cephalometric evaluation of the alterations taking place in the morphology of the pharyngeal airway space after treatment of class III skeletal deformity via different surgical procedures [i.e. mandibular setback, maxillary advancement, bimaxillary surgery] in both males and females
Methods: This study is a before-after cross sectional retrospective research. One hundred and twenty consecutive patients who were diagnosed as having skeletal class III deformity. All patients included in this study were adults who had completed their growth and had cephalograms within a month prior to operation [T1] and 1 month to 9 months post-surgery [T2] taken in the natural head position. Patients were divided according to the type of surgery undertaken in three groups: group 1 [bimaxillary], group 2 [mandibular setback] and group 3 [maxillary advancement] surgeries. Posterior airway size was evaluated at both T1 and T2 in each group. The results were compared by paired t and one-way ANOVA tests
Results: Airway size decreased significantly in group 1 and 2 [p<0.05] but increased in group 3[p<0.05]
Conclusion: Airway dimension and morphology as well as head and neck posture changed significantly in different surgical treatments of class III deformity
ABSTRACT
Statement of the Problem: The validity of the Index of Complexity, Outcome and Need [ICON] which is an orthodontic index developed and introduced in 2000 should be studied in different ethnic groups
Purpose: The aim of this study was to perform an analysis on the ICON and to verify whether this index is valid for assessing both the need and complexity of orthodontic treatment in Iran
Materials and Method: Five orthodontists were asked to score pre-treatment diagnostic records of 100 patients with a uniform distribution of different types of malocclusions determined by Dental Health Component of the Index of Treatment Need. A calibrated examiner also assessed the need for orthodontic treatment and complexity of the cases based on the ICON index as well as the Index of Orthodontic Treatment Need [IOTN]. 10 days later, 25% of the cases were re-scored by the panel of experts and the calibrated orthodontist
Results: The weighted kappa revealed the inter-examiner reliability of the experts to be 0.63 and 0.51 for the need and complexity components, respectively. ROC curve was used to assess the validity of the index. A new cut-off point was adjusted at 35 in lieu of 43 as the suggested cut-off point. This cut-off point showed the highest level of sensitivity and specificity in our society for orthodontic treatment need [0.77 and 0.78, respectively], but it failed to define definite ranges for the complexity of treatment
Conclusion: ICON is a valid index in assessing the need for treatment in Iran when the cut-off point is adjusted to 35. As for complexity of treatment, the index is not validated for our society. It seems that ICON is a well-suited substitute for the IOTN index
ABSTRACT
Skeletal class III malocclusions are considered as one of the most complex and difficult orthodontic problems to diagnose and treat. Facial appearance and occlusion problems make the patients to seek treatment as soon as possible. The purpose of this study was to evaluate the outcomes of early treatment with facemask compared to the patients who had no treatment. For this retrospective study, 38 growing patients [mean age, 8.5 years old] with class III dentoskeletal malocclusion were divided into 2 groups. 23 patients were treated with facemask and 15 patients who did not receive any treatment were assigned as control group. Lateral cephalograms were taken before and after treatment and dentoskeletal changes were estimated. Data were analyzed using Wilcoxon signed ranks test. The results revealed statistically significant forward displacement of maxillary bone and upper incisors [P<0.001], and downward-backward rotation of mandible in facemask group [P<0.001]. Increased lower facial height was seen in both treatment and untreated groups. However, in untreated group some measurements revealed forward displacement of maxillary complex as well. It seems that in class III patients, facemask therapy is a suitable choice for early treatment especially in patients with maxillary deficiency. Moreover, specific attention to the type of patient's skeletal discrepancy is necessary in treatment planning and appliance selection
Subject(s)
Humans , Male , Female , Child , Cephalometry , Masks , Retrospective StudiesABSTRACT
Programming for a successful operation and accurate prediction of the outcome of orthognathic surgery result in correction of occlusal and skeletal relations and improve the facial esthetics and function of patients. This retrospective study sought to assess the soft tissue changes following subcondylar and bilateral sagittal split osteotomy [BSSO] to retrude mandible in patients with mandibular prognathism. This retrospective experimental study evaluated 35 patients with mandibular prognathism and a mean age of 25.5 years [range 18.8 to 30.9 yrs]. Cephalometric variables were measured on lateral cephalograms of patients before and after surgery and recorded. A total of 12 patients had undergone BSSO while 23 subjects had received subcondylar surgery. Cephalometric variables were analyzed using paired t- and independent t-tests. The study results demonstrated that the mean changes in cephalometric soft tissue variables of Ls-Pr [P<0.05], Li-Id [P<0.01] and G-Sn/Sn-Me [P<0.05] after BSSO were significantly higher that the rates in Subcondylar surgery group. However, the mean changes in soft tissue variables of SLs-A [P<0.05], a2 facial angle [P<0.05] and LFH [P<0.001] in subcondylar surgery group were significantly higher than the rates in BSSO group. In patients that had undergone subcondylar surgery, the lower facial height and the mentocervical angle had increased which is indicative of a shift towards a straight facial profile after this type of surgery. This study showed that a greater improvement in profile is achieved after BSSO compared to subcondylar surgery according to the current esthetic parameters