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

ASLI BAYSAL |

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

Low-shrinking composites. Are they reliable for bonding orthodontic retainers?

TANCAN UYSAL

Makale | 2011 | The Korean Association of Orthodontists

To evaluate the shear bond strength (SBS), fracture mode, wire pull out (WPO) resistance and microleakage between low-shrinking and conventional composites used as a lingual retainer adhesive. Methods: A total of 120 human mandibular incisor teeth, extracted for periodontal reasons, were collected. Sixty of them were separated into two groups. To determine the SBS, either Transbond-LR (3M-Unitek) or Silorane (3M-Espe) was applied to the lingual surface of the teeth by packing the material into standard cylindrical plastic matrices (Ultradent) to simulate the lingual retainer bonding area. To test WPO resistance, 20 samples were prep . . .ared for each composite where the wire was embedded in the composite materialand cured. Then tensile stress was applied until failure of the composite occurred. The remaining 60 teeth were divided into two groups and multi-stranded 0.0215-inch diameter wire was bonded with the same composites. Microleakage was evaluated by the dye penetration method. Statistical analyses were performed by Wilcoxon, Pearson chi-square, and Mann-Whitney-U tests at p > 0.05 level. Results: The SBS and WPO results were not statistically significant between the two groups. Significant differences were found between the groups in terms of fracture mode (p > 0.001). Greater percentages of the fractures showed mix type failure (85%) for Silorane and adhesive (60%) for Transbond-LR. Microleakage values were lower in low-shrinking composite than the control and this difference was found to be statistically significant (p > 0.001). Conclusions: Low-shrinking composite produced sufficient SBS, WPO and micro-leakage values on the etched enamel surfaces, when used as a lingual retainer composite Daha fazlası Daha az

Comparison of three different orthodontic wires for bonded lingual retainer fabrication

ASLI BAYSAL |

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

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

ASLI BAYSAL | İLKNUR VELİ | MEHMET İRFAN KARADEDE

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

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

ASLI BAYSAL | İLKNUR VELİ

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

Cone-beam computed tomography assessment of mandibular asymmetry in unilateral cleft lip and palate patients

İLKNUR VELİ

Makale | 2011 | The Korean Association of Orthodontists

Objective: To determine whether there is any difference between the cleft and non-cleft sides of the mandible in unilateral cleft lip and palate (UCLP) patients, or the right and left sides in control patients; and to determine if there is any difference between the mandibular asymmetry of UCLP patients and that of control patients. Methods: We examined cone-beam computed tomography (CBCT) scans of 15 patients with UCLP and 15 age- and gender-matched control patients. We evaluated 8 linear, 3 surface, and 3 volumetric measurements and compared the cleft/non-cleft sides of UCLP patients and the right/left sides of controls. Res . . .ults: There were no statistically significant gender differences in any linear, surface, or volumetric measurement. The single significant side-to-side difference in UCLP patients was a longer coronoid unit on the cleft side than on the non-cleft side (p = 0.046). Body volume was significantly lower in the UCLP group than in the control group (p = 0.008). Conclusions: In general, UCLP patients have symmetrical mandibles, although the coronoid unit length is significantly longer on the cleft side than on the non-cleft side. UCLP patients and controls differed only in body volume Daha fazlası Daha az

Effects of demineralizaton-inhibition procedures on the bond strength of brackets bonded to demineralized enamel surface

TANCAN UYSAL

Makale | 2012 | The Korean Association of Orthodontists

Objective: To study and compare the effects of different demineralizationinhibition methods on the shear bond strength (SBS) and fracture mode of an adhesive used to bond orthodontic brackets to demineralized enamel surfaces. Methods: Eighty freshly extracted, human maxillary premolars were divided into 4 equal groups and demineralized over the course of 21 days. Brackets were bonded to the demineralized enamel of teeth in Group 1. In Group 2, bonding was performed following resin infi ltration (ICON®, DMG, Hamburg, Germany). Before bonding, pre-treatment with acidulated phosphate fluoride (APF) or solutions containing casei . . .n phosphopeptide-amorphous calcium phosphate with 2% neutral sodium fluoride (CPP-ACP/wF) was performed in Groups 3 and 4, respectively. Th e SBS values of the brackets were measured and recorded following mechanical shearing of the bracket from the tooth surface. Th e adhesive remnant index (ARI) scores were determined aft er the brackets failed. Statistical comparisons were performed using one-way ANOVA, Tukey’s post-tests, and G-tests. Results: Significant differences were found in some of the intergroup comparisons of the SBS values (F = 39.287, p < 0.001). No signifi cant diff erences were found between the values for the APF-gel and control groups, whereas signifi cantly higher SBS values were recorded for the resin-infi ltrated and CPPACP/ wF-treated groups. Th e ARI scores were also signifi cantly diff erent among the 4 groups (p < 0.001). Conclusions: Tooth surfaces exposed to resin infi ltration and CPP-ACP/wF application showed higher debonding forces than the untreated, demineralized surfaces Daha fazlası Daha az

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