Milena Kostić

Residual monomer content determination in some acrylic denture base materials and possibilities of its reduction

BACKGROUND/AIM Polymethyl methacrylate is used for producing a denture basis. It is a material made by the polymerization process of methyl methacrylate. Despite of the polymerization type, there is a certain amount of free methyl methacrylate (residual monomer) incorporated in the denture, which can cause irritation of the oral mucosa. The aim of this study was to determine the amount of residual monomer in four different denture base acrylic resins by liquid chromatography and the possibility of its reduction. METHODS After the polymerization, a postpolymerization treatment was performed in three different ways: in boiling water for thirty minutes, with 500 W microwaves for three minutes and in steam bath at 22 degrees C for one to thirty days. RESULTS The obtained results showed that the amount of residual monomer is significantly higher in cold polymerizing acrylates (9.1-11%). The amount of residual monomer after hot polymerization was in the tolerance range (0.59-0.86%). CONCLUSION The obtained results denote a low content of residual monomer in the samples which have undergone postpolymerization treatment. A lower percent of residual monomer is established in samples undergone a hot polymerization.

Мултицентричан идентитет Давида Албахарија, српско-канадског писца јеврејске вероисповести

Besides spatial dynamics, Albahari’s literary poetics is to a great extent defined by his religious affiliation. The article aims to show how Albahari’s different personal reference points (Serbia, Canada, Jewishness) build up the image of Albahari as an author comfortable in the emerging multicentric cultural economy.

Extraction and non-extraction therapy in class II/1 patients

Introduction: Class II malocclusion is characterized by distoclusion and is divided into two divisions depending on the inclination of the upper front teeth. The first division is characterized by protrusion of the upper front teeth. Treatment possibilities of class II/1 malocclusion depend on the skeletal form. Therapy of dentoalveolar types of class II/1 malocclusion is exclusively orthodontic. More emphasized skeletal forms of class II/1 malocclusion may require surgery apart from orthodontic therapy. Casse raport: In this paper, the extraction and nonextraction treatment of 13 years old patients - M.P.(boy) and I.T. (girl) was shown, respectively. The diagnosis was based on clinical and functional intraoral findings, analysis of dental casts, face photos, orthopatomogram and profile x-ray. Nonextraction therapy was suggested for a boy and extraction therapy for a girl, combined with the use of upper and lower fixed appliances. In the treatment, technique of straight arch, Dentaurum brackets, root prescriptions, slot 22 were used. In the male patient, there was a slight maxillary prognathism, mandibular retrognathism, anterior type of growth, protrusion of the upper incisors and retrusion of the lower ones. The body of maxilla was shorter by 4 mm with regard to the cranial base. In the female patient the extraction of the upper first premolars was performed because of maxillary prognathism, mandibular retrognathism, increased length of the body of maxilla, decreased length of the body of maxilla and severe protrusion of the upper frontal teeth. After the treatment, functional occlusion and improvement in facial aesthetics was achieved in both patients. Facial changes were more apparent in the patient who underwent the extraction treatment. After completion of treatment, it is necessary to maintain the obtained results.