Biological Properties of the Aggregated Form of Chitosan Magnetic Nanoparticle.

BACKGROUND/AIM: Chitosan-coated iron oxide nanoparticles (Chi-NP) have gained attention because of their biocompatibility, biodegradability, low toxicity and targetability under magnetic field. In this study, we investigated various biological properties of Chi-NP. MATERIALS AND METHODS: Chi-NP was prepared by mixing magnetic NP with chitosan FL-80. Particle size was determined by scanning and transmission electron microscopes, cell viability by MTT assay, cell cycle distribution by cell sorter, synergism with anticancer drugs by combination index, PGE2 production in human gingival fibroblast was assayed by ELISA. RESULTS: The synthetic process of Chi-NP from FL-80 and magnetic NP increased the affinity to cells, up to the level attained by nanofibers. Upon contact with the culture medium, Chi-NP instantly formed aggregates and interfered with intracellular uptake. Aggregated Chi-NP did not show cytotoxicity, synergism with anticancer drugs, induce apoptosis (accumulation of subG1 cell population), protect the cells from X-ray-induced damage, nor affected both basal and IL-1ß-induced PGE2 production. CONCLUSION: Chi-NP is biologically inert and shows high affinity to cells, further confirming its superiority as a scaffold for drug delivery.

Treatment and posttreatment effects of mandibular cervical headgear followed by fixed appliances in Class III malocclusion.

INTRODUCTION: In this cephalometric investigation, we compared the treatment and posttreatment effects on patients undergoing an initial phase of mandibular cervical headgear (MCH) therapy followed later by comprehensive edgewise therapy with untreated Class III controls. METHODS: The treated sample consisted of 21 patients treated consecutively with MCH before the pubertal growth spurt (average age, 10 years 2 months at the beginning of treatment). At the final observation period (average age, 15 years 3 months), all patients were in decelerative growth phases as determined by the cervical vertebral maturation method. Active treatment and posttreatment effects were evaluated in the treated group with nonparametric statistical analysis for paired samples. The treated sample was compared with a nonparametric statistical test for independent samples with 20 untreated Class III subjects who were matched for malocclusion, sex, and stage of cervical vertebral maturation to the treatment group. RESULTS AND CONCLUSIONS: MCH therapy followed by fixed appliances was shown to be an effective treatment for the correction of skeletal Class III malocclusion at postpubertal observation. The favorable skeletal effects consisted mainly of smaller increases in mandibular length and advancement with respect to the controls, with the final outcome of significant improvements in the sagittal skeletal (+4 mm for the Wits appraisal) and dental (+2.7 mm for overjet, -4.4 mm for molar relationship) parameters. This treatment protocol also induced significant downward rotation of the mandible (2.8 degrees ).

Mandibular cervical headgear vs rapid maxillary expander and facemask for orthopedic treatment of Class III malocclusion.

OBJECTIVE: To compare the effectiveness of the rapid maxillary expander and facemask (RME/ FM) and mandibular cervical headgear (MCH) protocols when followed by fixed appliances and evaluated at a postpubertal observation in patients with dentoskeletal Class III malocclusion. MATERIALS AND METHODS: The sample treated with the RME/FM followed by fixed appliances included 32 patients (12 boys and 20 girls). The sample treated with the MCH followed by fixed appliances included 26 patients (eight boys and 18 girls). Cephalometric analysis was performed at T(1) (before treatment) and T(2) (after the first phase of orthopedic therapy and the second phase of fixed appliances). T(1)-T(2) changes were evaluated by means of t-tests. RESULTS: Midfacial length, mandibular length, and the sagittal position of the chin all showed significantly smaller increases in the MCH group than in the RME/FM group. The amount of increase in the overjet was also significantly smaller in the MCH group, whereas the amount of molar correction was greater. The upper incisors were significantly less proclined and the lower incisors were significantly less retroclined in the MCH group when compared with the RME/FM group. CONCLUSIONS: RME/FM therapy appears to be indicated in Class III patients with a component of maxillary retrusion, whereas MCH therapy is preferable in patients with mandibular prognathism.

Mandibular cervical headgear in orthopedic and orthodontic treatment of Class III cases.

AIM: To show craniofacial and dental changes to the mandibular dentition with the use of cervical headgear as well as the mechanics used in the early management of Class III malocclusions. METHODS: Clinical photos and cephalometric radiographs of 5 patients with different types of Class III malocclusion treated with mandibular cervical headgear are shown in this article. RESULTS: The use of the mandibular cervical headgear showed to be clinically effective in the treatment of different types of Class III malocclusions. The main effects of the appliance were posterior and anterior rotation of the mandible and distalization of the mandibular molars. CONCLUSION: The mandibular cervical headgear is a good alternative for the treatment of these cases and is well-accepted and tolerated by the patients.

Estudio cefalométrico de pacientes con maloclusión clase III tratados con tracción cervical inferior: Estudios e intervención retrospectivo / Retrospective cephalometric study of patients with class III malocclusions treated with mandibular headgear

El propósito del estudio fue evaluar cefalométricamente los cambios esqueléticos y dentales producidos en pacientes tratados tempranamente con tracción cervical mandibular seguidos de ortodoncia...