Esfandiar Akhavan Niaki; Masomeh Esmaily; Yasamin Farajzadeh Jalali
Abstract
Background: Bonding is the most commonly used technique to attach brackets to tooth surfaces.
Objectives: The aim of this study was to determine the effects of time and concentration of etching with phosphoric acid on shear bond strength (SBS) of orthodontic brackets after using 10-MDP containing adhesive.
Methods: ...
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Background: Bonding is the most commonly used technique to attach brackets to tooth surfaces.
Objectives: The aim of this study was to determine the effects of time and concentration of etching with phosphoric acid on shear bond strength (SBS) of orthodontic brackets after using 10-MDP containing adhesive.
Methods: Fifty intact premolars were randomly divided into 5 groups (n = 10). They were mounted in resin blocks. In control group a gel without phosphoric acid and in-group 2, 3, 4, and 5, phosphoric acid 37% for 5 or 15 seconds and phosphoric acid 15% for 5 or 15 seconds was used respectively. Clearfil SE Bond was used as an adhesive resin for all samples. After bonding of brackets, they were put under 300 thermocycling aging regime and after that the bracket/tooth SBS was measured by universal testing machine. The adhesive remnant index (ARI) was evaluated under a stereomicroscope. Data were statistically analyzed using two-way ANOVA and Kruskal-Wallis test. Results: The highest mean SBS belonged to the 15% phosphoric acid etching in 15 seconds while the lowest value was seen in 37% phosphoric acid etching in 5 seconds. The effect of etching time on SBS was not significant (P = 0.31) but the effect of concentration in SBS has been significant (P < 0.001). In terms of ARI, in application of 15% phosphoric acid, more than 50% of the resin remained on tooth surface. In application of 37% phosphoric acid, all the resin remained on tooth surface.
Conclusions: In using of Clearfil SE bond, containing 10-MDP, preparing enamel by 15% phosphoric acid had created strong enough SBS.
Ib Leth Nielsen
Abstract
Early treatment of Class II, Div. 1 malocclusion is a much debated approach and some evidenced based studies using a single appliance has concluded that this approach was mostly not worthwhile. This article will discuss the pros and cons of early treatment with functional appliances and present guidelines ...
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Early treatment of Class II, Div. 1 malocclusion is a much debated approach and some evidenced based studies using a single appliance has concluded that this approach was mostly not worthwhile. This article will discuss the pros and cons of early treatment with functional appliances and present guidelines for early treatment. The role of facial growth and dentoalveolar development, and growth intensity will be discussed as they relate to treatment outcome.
Soodeh Tahmasbi; Sattar Kabiri; Elham Mohammad Rabei
Abstract
Introduction: Tooth eruption is a complex procedure and many theories has been proposed to describe the nature of this process. Some studies, have shown that in contrast to traditional thoughts, root development is not necessary for tooth eruption and have been focused on the role of dental follicle. ...
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Introduction: Tooth eruption is a complex procedure and many theories has been proposed to describe the nature of this process. Some studies, have shown that in contrast to traditional thoughts, root development is not necessary for tooth eruption and have been focused on the role of dental follicle. Eruption of the permanent teeth with no or little root development has been reported in a few cases. Dentin dysplasia is a rare genetic disorder of the teeth that affect dentin formation. Dentin dysplasia type I or radicular dentin dysplasia is characterized by normal appearance of crowns, but severe tooth mobility. Radiographically, very short or absent roots, periapical lesions and spontaneous pulp obliteration are seen.
Case Presentation: This paper describes two patient with dentin dysplasia type I that despite of rootless tooth, normal eruption has occurred.
Conclusions: These cases are good example to support that eruption procedure is an independent event from root formation.
Sanaz Soheilifar; Mohammad Ali Momeni
Abstract
Background: According to the close proximity of hyoid bone with dentofacial structures and its muscular attachments, a probable relationship between it and different types of skeletal patterns is suspected.
Objectives: The aim of this study is compare the position of hyoid bone in skeletal class I and ...
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Background: According to the close proximity of hyoid bone with dentofacial structures and its muscular attachments, a probable relationship between it and different types of skeletal patterns is suspected.
Objectives: The aim of this study is compare the position of hyoid bone in skeletal class I and class II patients.
Methods: In this study 50 cephalograms were divided into two groups, skeletal class I (1 ≤ ANB ≤ 4) and skeletal class II (ANB > 4), with 24 and 26 patients in each group, respectively. Horizontal and vertical position of hyoid bone were evaluated. SPSS software and student t-test were used to analyze the data. Results: According to the results of our study, there is no statistically significant difference between the hyoid bone position in skeletal class I and skeletal class II patients.
Conclusions: Since the hyoid bone position is similar in skeletal class I and class II patients, the skeletal pattern is not the only determinant of the position of hyoid bone.
Tahereh Hosseinzadeh Nik; Toktam Jalayer; Amine Beymouri; Atefe Saffar Shahroudi; Armin Eftekhari
Abstract
Background: Third molar impaction is a major problem facing the dental profession and its impacts on the dentition has long been a major concern. Third molar is the most frequently impacted tooth. The prevalence of mandibular third molar impaction has been reported from 18 to 32 percent which varies ...
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Background: Third molar impaction is a major problem facing the dental profession and its impacts on the dentition has long been a major concern. Third molar is the most frequently impacted tooth. The prevalence of mandibular third molar impaction has been reported from 18 to 32 percent which varies between populations and races.
Objectives: This study was designed to determine the best retromolar space analysis from available methods with the highest correlation with mesio-distal width of mandibular third molar (MTM) in order to predict its eruption or impaction.
Patients and Methods: Measurements were carried out on digital panoramic radiographs of 98 Iranian patients. One hundred and seventy mandibular third molars were divided into 4 groups: impacted females, impacted males, erupted females and erupted males. Twenty eight points and 24 planes were marked on the radiographs: 11 points in relation to retromolar space analysis and the mesio-distal width of MTM; and 17 points in relation to some anatomic variables assumed to be related to MTM eruption or impaction. Using these landmarks, different methods were tested for analyzing the retromolar space and its relation to the width of the MTM. Student’s t-test was applied for comparison between erupted and impacted groups and ROC curve was drawn to determine the method with the highest specificity and sensitivity.
Results: Among the performed retromolar space analysis, the method that measured the distance between distal surface of second molar and the anterior border of ramus parallel to functional occlusal plane had the highest correlation with the MTM width. Also, the impact of some anatomic factors including posterior ramus height, upper body length, etc. on MTM eruption or impaction was observed.
Conclusions: Retromolar space analysis on panoramic radiographs can be a relatively precise predictor for mandibular third molar eruption or impaction. This study also supports the multifactorial concept about third molar impaction.
Amanda Carneiro da Cunha; Mariana Marquezan; Lincoln Issamu Nojima; Eduardo Franzotti Sant’Anna
Abstract
Background: Orthodontic mini-implants represent one of the most used anchorage systems in daily clinical practice and frequently, these anchorage devices have to be placed between the roots of adjacent teeth reflecting the need to limit its dimensions. Among other factors, it has been suggested that ...
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Background: Orthodontic mini-implants represent one of the most used anchorage systems in daily clinical practice and frequently, these anchorage devices have to be placed between the roots of adjacent teeth reflecting the need to limit its dimensions. Among other factors, it has been suggested that mini-implant’s geometry have a great impact on primary stability.
Objectives: The aim of this study was to evaluate the primary stability (PS) of commercially available orthodontic mini-implants (MI) of different geometrical designs.
Methods: Twenty self-drilling MI (1.6 mm × 8 mm) were allocated to two groups (n = 10) according to their geometric design: INP-1 and INP-2. Twenty sections (8 mm ø × 10 mm long) were taken from bovine pelve, immersed in saline solution and stored by freezing (-20°C). Geometric characteristics concerning shape, diameter, length, pitch, thread details (number, angle and depth), thread shape factor (TSF) and conicity were evaluated by using Scanning Electron Microscope (SEM) imaging and all the measurements were carried out with Image-Pro® Insight Software. PS was evaluated by insertion torque (IT) and Periotest (PTV). Intergroup comparisons were made by Student t test. The level of significance was 5%. Results: Increased IT values were observed for INP-1 (20.08 ± 3.28 N.cm) (P < 0.05), the group that presented the greatest conicity (33%) and highest thread depth (0.19 mm).
Conclusions: The wide geometric variability of MI indicates that MI design parameters affect its PS and it could be selected in order to improve its mechanical performance.
Soghra Yassaei; Hossein Aghili; Zahra Ebrahimi Nik; Hossein Abedi Ardakani
Abstract
Objectives: The aim of this study was to compare the maxillary sinus sizes in patients with maxillary excess and maxillary deficiency.
Methods: 120 cephalometric and panoramic radiographs of 12 - 25 years old patients were studied. These radiographs were derived from patients with maxillary deficiency, ...
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Objectives: The aim of this study was to compare the maxillary sinus sizes in patients with maxillary excess and maxillary deficiency.
Methods: 120 cephalometric and panoramic radiographs of 12 - 25 years old patients were studied. These radiographs were derived from patients with maxillary deficiency, normal, or excess. Each group consisted of 40 Patients, (20 females and 20 males). Different dimensions of maxillary sinus included maxillary sinus anterior posterior length (M.S.L), maxillary sinus height (M.S.H) and total maxillary sinus area (TMSA) were measured by digital lateral cephalometry and digital panoramic analysis. In AutoCAD program the lines were measured by mm and the area were measured (mm2). All input images into AutoCAD program converted to a unit scale to assess the minimal magnification error. Data were analyzed using t-test and ANOVA. Results: TMSA was highest in the maxillary deficiency group following by the maxillary normal and maxillary excess groups which the differences were statistically significant (P value = 0.008). However no significant differences were noticed by panoramic image measurements (P value = 0.285). The mean of MSH was significantly higher in the maxillary deficiency group compared with the maxillary normal and maxillary excess groups, both in lateral cephalometry (P value < 0.001) and panoramic images (P value = 0.034). Regarding the MSL no significant differences were seen among the study groups both in lateral cephalometry and panoramic images.
Conclusions: According to the result of this study TMSA and MSH were significantly higher in maxillary deficiency group in comparison with the maxillary normal and excess groups.
Giulia Gay; Serena Ravera; Tommaso Castroflorio; Francesco Garino; Giovanni Cugliari; Andrea Deregibus
Abstract
Background: Existing literature indicates that orthodontics patients are more likely to have severe apical root shortening, interesting mostly maxillary, followed by mandibular incisors.
Objectives: The aim of the present study was to investigate the incidence and severity of root resorption (RR) in ...
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Background: Existing literature indicates that orthodontics patients are more likely to have severe apical root shortening, interesting mostly maxillary, followed by mandibular incisors.
Objectives: The aim of the present study was to investigate the incidence and severity of root resorption (RR) in mandibular incisors of adult patients treated with aligners.
Methods: The study group consisted of 71 adult healthy patients (mean age 32.8 ± 12.7) treated with aligners (Invisalign®, Align Technologies, San Jose, CA, USA) for the intrusion of the lower incisors. Root and crown lengths of a total of 279 lower incisors were measured in panoramic radiographs at the beginning (T0) and at the end (T1) of aligner therapy. Individual root-crown-ratio (RCR) of each tooth and therefore the relative changes of RCR (rRCR) were determined. Results: 44% of the 279 measured teeth presented a reduction of the pre-treatment root length. A reduction in percentage of > 0% up to 10% was found in 26.76% (n = 76), a distinct reduction of > 10% up to 20% in 12.32% (n = 35) of the sample. 4.58% (n = 13) of the teeth were affected by a clinically relevant reduction (> 20%).
Conclusions: Orthodontic treatment with Invisalign® aligners could led to RR in cases in which intrusion of the lower incisors is planned. However, the incidence of RR is comparable to data described in case of application of light forces with fixed appliances, and considerably lower than what has been described for traditional comprehensive orthodontic treatments.
