Measurements from conventional, digital and CT-derived cephalograms: a comparative study


Makale | 2012 | Australian Society of Orthodontists

Objective: The purpose of this retrospective radiographic study was to determine the reliability and reproducibility of skeletal and dental measurements of lateral cephalograms created from a computerised tomography (CT) scan compared with conventional and digital lateral cephalograms. Methods: CT and conventional lateral cephalograms of the same patients were obtained from university archives. The lateral cephalometric radiographs of 30 patients were manually traced. The radiographs were subsequently scanned and traced using Dolphin Imaging software version 11 (Dolphin Imaging, Chatsworth, CA, USA). The CT-created lateral ceph . . .alograms were also traced using the same software. Sixteen (10 angular and 6 linear) measurements were performed. Cephalometric measurements obtained from conventional, digital and CT-created cephalograms were statistically compared using repeated measures analysis of variance (ANOVA). Statistical significance was set at the p < 0.05 level of confidence. Results: The intra-rater reliability test for each method showed high values (r > 0.90) except for mandibular length which had a correlation of 0.82 for the CT-created cephalogram. Five measurements (N-A-Pog, N-S, ANS-PNS, Co-ANS and Co-Gn) were found to be significantly different between the CT-created and conventional cephalograms and three measurements (SNB, ANB, and /1-MP) were found to be significantly different between the CT-created and digital cephalograms. Conclusions: There are statistically-significant differences in measurements produced using a traditional manual analysis, a direct digital analysis or a 3D CT-derived cephalometric analysis of orthodontic patients. These differences are, on average, small but because of individual variation, may be of considerable clinical significance in some patients Daha fazlası Daha az

Dentoskeletal effects of Twin Block and Herbst appliances in patients with Class II division 1 mandibular retrognathy


Makale | 2014 | European Orthodontic Society

OBJECTIVE: The aim of this study is to evaluate dentoskeletal effects of Herbst and Twin Block (TB) appliance therapies in Skeletal Class II malocclusion. SUBJECTS AND METHODS: Herbst group consisted of 11 girls and 9 boys (mean age = 12.74±1.43 years), TB group comprised of 10 girls and 10 boys (mean age = 13.0±1.32 years), and control group included 9 girls and 11 boys (mean age = 12.17±1.47 years). Mean treatment/observation times were 15.81±5.96 months for Herbst, 16.20±7.54 months for TB, and 15.58±3.13 months for control group. Pre-treatment (T0) and post-treatment (T1) lateral cephalograms were traced using a modified Panc . . .herz’s cephalometric analysis. Inter-group differences were evaluated with one-way analysis of variance, and intra-group differences were assessed with paired samples t-test at the P < 0.05 level. RESULTS: In control group, all sagittal and vertical skeletal measurements increased as a result of continuing growth. However, skeletal discrepancy and overjet remained unchanged. After functional appliance therapy, greater increases were recorded in TB group for all mandibular skeletal measurements compared with those in control group. Upper dental arch distalization and lower incisor protrusion were significant in Herbst group, compared with control. All face height measurements increased after functional appliance therapy. IMPLICATIONS AND CONCLUSIONS: In TB group, the treatment effects were mainly due to mandibular skeletal changes. Both skeletal and dental changes contribute to Class II correction with Herbst appliance therapy. Herbst appliance may be especially useful in Skeletal Class II patients with maxillary dentoalveolar protrusion and mandibular dentoalveolar retrusion, whereas TB appliance may be preferred for skeletal mandibular retrognathy patients Daha fazlası Daha az

Comparison of three different orthodontic wires for bonded lingual retainer fabrication


Makale | 2012 | The Korean Association of Orthodontists

Objective We evaluated the detachment force, amount of deformation, fracture mode, and pull-out force of 3 different wires used for bonded lingual retainer fabrication. Methods We tested 0.0215-inch five-stranded wire (PentaOne, Masel; group I), 0.016 × 0.022-inch dead-soft eight-braided wire (Bond-A-Braid, Reliance; group II), and 0.0195-inch dead-soft coaxial wire (Respond, Ormco; group III). To test detachment force, deformation, and fracture mode, we embedded 94 lower incisor teeth in acrylic blocks in pairs. Retainer wires were bonded to the teeth and vertically directed force was applied to the wire. To test pull-out forc . . .e, wires were embedded in composite that was placed in a hole at the center of an acrylic block. Tensile force was applied along the long axis of the wire. Results Detachment force and mode of fracture were not different between groups. Deformation was significantly higher in groups II and III than in group I (p < 0.001). Mean pull-out force was significantly higher for group I compared to groups II and III (p < 0.001). Conclusions Detachment force and fracture mode were similar for all wires, but greater deformations were seen in dead-soft wires. Wire pull-out force was significantly higher for five-stranded coaxial wire than for the other wires tested. Five-stranded coaxial wires are suggested for use in bonded lingual retainers Daha fazlası Daha az

Ethnic differences in the soft tissue profiles of Turkish and European–American young adults with normal occlusions and well-balanced faces


Makale | 2012 | Oxford University Press on behalf of the European Orthodontic Society

The aim of this study was to evaluate soft tissue differences between Turkish and North American adults by comparing two sample populations with ideal occlusion and well-balanced faces. Lateral cephalometric radiographs of 117 Anatolian Turkish adults (65 female and 52 male, mean age: 23.9 ± 2.8 years) were compared with a sample of 116 adults of European–American ancestry (64 female and 52 male, mean age: 25.0 ± 6.8 years). The cephalometric analyses of Holdaway, Epker, and Legan and Burstone were performed using Dolphin Image Software 9.0. Thirty-two measurements (27 linear and 5 angular) were analysed. For statistical evaluation, . . . independent samples t-tests were performed. Distinct differences were found between the two samples in facial convexity, upper lip position and length, lower lip position, chin prominence, and chin thickness. Vertical proportional findings were similar between groups. Ethnic differences were found between Turkish and North American adults in the soft tissue profile. It is appropriate to consider these differences during routine diagnosis and treatment planning of a Turkish patient or an American patient of European ancestry Daha fazlası Daha az

Alveolar bone thickness and lower incisor position in skeletal Class I and Class II malocclusions assessed with cone-beam computed tomography


Makale | 2013 | The Korean Association of Orthodontists

Objective: To evaluate lower incisor position and bony support between patients with Class II average- and high-angle malocclusions and compare with the patients presenting Class I malocclusions. Methods: CBCT records of 79 patients were divided into 2 groups according to sagittal jaw relationships: Class I and II. Each group was further divided into average- and high-angle subgroups. Six angular and 6 linear measurements were performed. Independent samples t-test, Kruskal–Wallis, and Dunn post-hoc tests were performed for statistical comparisons. Results: Labial alveolar bone thickness was significantly higher in Cl . . .ass I group compared to Class II group (p = 0.003). Lingual alveolar bone angle (p = 0.004), lower incisor protrusion (p = 0.007) and proclination (p = 0.046) were greatest in Class II average-angle patients. Spongious bone was thinner (p = 0.016) and root apex was closer to the labial cortex in high-angle subgroups when compared to the Class II average-angle subgroup (p = 0.004). Conclusions: Mandibular anterior bony support and lower incisor position were different between average- and high-angle Class II patients. Clinicians should be aware that the range of lower incisor movement in high-angle Class II patients is limited compared to average- angle Class II patients Daha fazlası Daha az

Evaluation of root resorption following rapid maxillary expansion using cone-beam computed tomography


Makale | 2012 | The E. H. Angle Education and Research Foundation

Objective: To evaluate the root resorption after rapid maxillary expansion (RME) via cone-beam computed tomography (CBCT). Materials and Methods: Records of 25 patients who had undergone RME with tooth-borne banded expander were obtained from the archive of the orthodontic department. CBCT data were reconstructed with surface and volume rendering, and the volumetric images were manipulated to display the root surfaces from various orientations. On these three-dimensional images, permanent first molars and first and second premolars were segmented, and their roots were isolated. Volumes of roots were calculated. The difference . . . between pre-expansion and postexpansion root volumes was statistically evaluated with a paired-samples t-test. Also, the percentage of root volume loss was calculated for each root and statistically compared with each other with one-way analysis of variance at the P , .05 level. Results: The difference between the pre-expansion and postexpansion root volumes was statistically significant for all roots investigated. Maximum volume decrease was observed for the mesiobuccal root of first molar teeth (18.60 mm3). It was determined that the distobuccal root of first molar teeth was less affected from the expansion procedure (9.47 mm3). No statistically significant difference was found for the percentage of root volume loss. Conclusion: Following RME treatment, significant root volume loss was observed for all investigated posterior teeth. However, the percentage of volume loss was not statistically different among roots. (Angle Orthod. 2012;82:488–494. Daha fazlası Daha az

Evaluation of alveolar bone loss following rapid maxillary expansion using cone-beam computed tomography


Makale | 2013 | The Korean Association of Orthodontists

Objective: To evaluate the changes in cortical bone thickness, alveolar bone height, and the incidence of dehiscence and fenestration in the surrounding alveolar bone of posterior teeth after rapid maxillary expansion (RME) treatment using cone-beam computed tomography (CBCT). Methods: The CBCT records of 20 subjects (9 boys, mean age: 13.97 ± 1.17 years; 11 girls, mean age: 13.53 ± 2.12 year) that underwent RME were selected from the archives. CBCT scans had been taken before (T1) and after (T2) the RME. Moreover, 10 of the subjects had 6-month retention (T3) records. We used the CBCT data to evaluate the buccal and . . . palatal aspects of the canines, first and second premolars, and the first molars at 3 vertical levels. The cortical bone thickness and alveolar bone height at T1 and T2 were evaluated with the paired-samples t-test or the Wilcoxon signed-rank test. Repeated measure ANOVA or the Friedman test was used to evaluate the statistical significance at T1, T2, and T3. Statistical significance was set at p < 0.05. Results: The buccal cortical bone thickness decreased gradually from baseline to the end of the retention period. After expansion, the buccal alveolar bone height was reduced significantly; however, this change was not statistically significant after the 6-month retention period. During the course of the treatment, the incidence of dehiscence and fenestration increased and decreased, respectively. Conclusions: RME may have detrimental effects on the supporting alveolar bone, since the thickness and height of the buccal alveolar bone decreased during the retention period Daha fazlası Daha az

Do enamel microabrasion and casein phosphopeptide-amorphous calcium phosphate affect shear bond strength of orthodontic brackets bonded to a demineralized enamel surface?


Makale | 2012 | The E. H. Angle Education and Research Foundation

Objective: To evaluate and compare the effects of enamel microabrasion, casein phosphopeptide-amorphous calcium phosphate (CPP-ACP), and their combination on the shear bond strength (SBS) of orthodontic brackets bonded to demineralized enamel surface. Materials and Methods: One hundred human first premolar teeth were randomly allocated to one of five groups. Group I was considered as the control of other groups. For the remaining groups, demineralization was performed via solutions. In group II, brackets were directly bonded to the demineralized enamel surface. CPP-ACP was applied in group III, microabrasion was performed in grou . . .p IV, and both microabrasion and CPP-ACP application were performed in group V. The specimens were tested for SBS. Bond failures were scored according to the Adhesive Remnant Index (ARI). Analysis of variance and Tukey tests were used to compare the SBS of the groups. ARI scores of the groups were evaluated with a G-test. The statistical significance was set at P Daha fazlası Daha az

Changes in mandibular transversal arch dimensions after rapid maxillary expansion procedure assessed through cone-beam computed


Makale | 2011 | The Korean Association of Orthodontists

Objective: This study aimed at evaluating the changes in mandibular arch widths and buccolingual inclinations of mandibular posterior teeth after rapid maxillary expansion (RME). Methods: Baseline and post expansion cone-beam computed tomographic (CBCT) images of patients who initially had bilateral posterior cross-bite and underwent RME with a banded type expander were assessed in this study. The patients included 9 boys (mean age: 13.97 1.17 years) and 11 girls (mean age: 13.53 2.12 years). Images obtained 6 months after retention were available for 10 of these patients. Eighteen angular and 43 linear measurements were performed f . . .or the maxilla and mandible. The measurements were performed on frontally clipped images at the following time points; before expansion (T1), after expansion (T2), and after retention (T3). Statistical significance was assessed with paired sample t test at 0.05. Results: T1 T2 comparisons showed statistically significant post RME increases for all measurements; similarly, T2 T1 and T3 T1 comparisons showed statistically significant changes. The maxillary linear and angular measurements showed decreases after expansion, and mandibular linear and angular measurements increased after retention. Conclusion: All mandibular arch widths increased and mandibular posterior teeth were uprighted after RME procedure Daha fazlası Daha az

EMG PSD Measures in Orthodontic Appliances


Kitap Bölümü | 2011 | InTech

The human body consists of different systems which include the nervous system, the cardiovascular system, the musculoskeletal system, etc. Each system performs some kind of vital task and carries on many physiological processes. For example, the primary functions of the musculoskeletal system can be summarized as generating forces, producing motion, moving substance within the body, providing stabilization, and generating heat. Physiological processes are multifaceted fact and most of them manifest themselves as signals that reflect their nature and activities. These types of signals may be hormonal, physical or electrical. The gene . . .ral name of the electrical signals taken from the related organ or physiologic process with invasive or non-invasive methods is called Biomedical Signals. This signal is normally a function of time and is definable in terms of its amplitude, frequency and phase (Rangayyan, 2002). The electromyography (EMG) signal is a biomedical signal that detects the electrical potential generated by muscle cells when these cells contract, and also when the cells are at rest. Three types of muscle tissue can be identified. One of them is the skeletal muscle, and the others are the smooth muscle and the cardiac muscle. The EMG is applied to the study of skeletal muscle (Reaz et al., 2006). Skeletal muscles are comprised by nearly parallel cells and the muscle fibers which constitute the contractile structural units. Muscle fibers are activated by the central nervous system through electrical signals transmitted by motoneurons. A single motoneuron together with the muscle fibers that it contacts is called a motor unit which is the smallest functional subdivision of the neuromuscular system (Moritani, et al. 2004) The central nervous system controls the activation of motor units to optimize the interaction between our body and the surrounding environment. When the motor units are activated by the central nervous system, they produce an action potential trains of the active motor units add together to generate the interference EMG signal. Surface and needle electrodes have been used to detect EMG of muscles. Surface electrodes have been widely used to investigate neuromuscular functions because of their several advantages, for example, it is noninvasive, easy to adhere to the skin and to detect the total activities of the muscle and it was called Surface EMG (SEMG). Bu the real advantage of this technique is that it is more beneficial in studies, in which simultaneous movement of many muscles is examined in vast muscle groups. On the other hand, surface electrodes have disadvantages as well. Due to the broad area for receiving signals on respective muscl Daha fazlası Daha az

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