Microbial contamination of laboratory constructed removable orthodontic appliances

OBJECTIVES: This study aims to determine whether laboratory constructed removable orthodontic appliances are free from microbial contamination prior to clinical use and to evaluate the dental hospital cross-infection procedures to ensure that patient-derived contamination does not enter the construction process, thereby propagating a cycle of cross-contamination.MATERIALS AND METHODS: The construction process of removable orthodontic appliances from three individuals was evaluated at every stage, from impression to final delivery of the appliance using molecular microbiological techniques. The bacterial profiles at each stage of appliance construction were obtained using denaturing gradient gel electrophoresis, along with the bacterial profiles of the three participants' saliva. This enabled the bacterial profiles found at each stage of construction to be compared directly with the saliva of the person for whom the appliance was being constructed. Bacteria were identified at each stage using 16S rDNA PCR amplification and sequence phylogeny.RESULTS: There was no evidence of bacterial cross-contamination from patients to the laboratory. The current process of disinfection of impression appears to be adequate. Contamination was found on the final removable appliances (0.97 × 10(2)-1.52 × 10(3) cfu ml(-1)), and this contamination occurred from within the laboratory itself.CONCLUSIONS: Every effort is made to reduce potential cross-infection to patients and dental professionals. Newly constructed removable appliances were shown not to be free from contamination with bacteria prior to clinical use, but this contamination is environmental. Further studies would be required to determine the level of risk this poses to patients.CLINICAL SIGNIFICANCE: Dental professionals have a duty of care to minimise or eradicate potential risks of cross-infection to patients and other members of the team. To date, much less attention has been paid to contamination from the orthodontic laboratory, so contamination and infection risks are unknown.</p

The anatomical, biological and psychological impact of electromagnetic radiation of mobile phones on human health

Recently, an enormous expansion of mobile telephony has taken place both internationally as well as in our country. Nevertheless, only few studies have dealt with the characteristics of the emitted electromagnetic radiation, the strategies followed during antennas’ installation, the mode of action of the emitted radio-waves and finally their effect on the human body. The aim of this PhD thesis was to perform data collection and processing pertinent to symptoms and pathophysiological damages caused by the use of electromagnetic radiation coming from mobile phones on human populations of different ages. The survey involved a total of 1470 people of different ages (120 individuals aged 12-18, 600 aged 18-25 years, 400 subjects aged 25-60 years, and 350 people aged over 60 years), who answered a special questionnaire, designed for the evaluation of the effects of mobile phones on already diagnosed diseases or diseases that occurred later. The duration of talking time was also used as a parameter of evaluation. Several conclusions were excluded on the effects of non-ionizing radiation of mobile phones in anatomical, biological and psychological level in order to formulate recommendations for safe use of mobile phones in different age groups.Η κινητή τηλεφωνία γνώρισε τεράστια εξάπλωση τα τελευταία χρόνια τόσο διεθνώς όσο και στη χώρα μας. Παρόλα αυτά λίγες εργασίες έχουν ασχοληθεί με τα χαρακτηριστικά της εκπεμπόμενης ηλεκτρομαγνητικής ακτινοβολίας, τους τρόπους εγκατάστασης των κεραιών, τον τρόπο δράσης των ραδιοκυμάτων που εκπέμπονται από τα κινητά τηλέφωνα και την επίδραση αυτών στον ανθρώπινο οργανισμό. Σκοπός της παρούσας διδακτορικής διατριβής ήταν η συλλογή και επεξεργασία πληροφοριών που αφορούν σε συμπτώματα και βλάβες που πιθανά προκαλούνται από την χρήση της ηλεκτρομαγνητικής ακτινοβολίας σε ανθρώπινους πληθυσμούς διαφόρων ηλικιών. Στην έρευνα συμμετείχε ένα σύνολο 1470 ανθρώπων διαφόρων ηλικιών (120 άτομα ηλικίας 12-18 ετών, 600 άτομα ηλικίας 18-25 ετών, 400 άτομα ηλικίας 25-60 ετών, και 350 άτομα ηλικίας μεγαλύτερης των 60 ετών), οι οποίοι απάντησαν σε ειδικό ερωτηματολόγιο αξιολόγησης των επιδράσεων της χρήσης κινητής τηλεφωνίας σε ήδη διαγνωσμένες παθήσεις ή σε νέες παθήσεις αν αυτές προκλήθηκαν μεταγενέστερα. Στην έρευνα αξιολογήθηκε και η παράμετρος του χρόνου ομιλίας του κινητού τηλεφώνου. Εξήχθησαν συμπεράσματα σχετικά με τις επιπτώσεις της μη ιονίζουσας ακτινοβολίας των κινητών τηλεφώνων σε ανατομικό, βιολογικό και ψυχολογικό επίπεδο και διατυπώθηκαν προτάσεις για την ασφαλή χρήση της κινητής τηλεφωνίας στις διάφορες ηλικιακές ομάδες

PHYSICAL PROPERTIES OF SOME DENTAL MODELLING WAXES

IN THE PRESENT STUDY A KINETIC INVESTIGATION OF THE CHANGES IN SHAPE OF DENTAL MODELLING WAXES AFTER THEIR MANIPULATION IN VARIOUS TEMPERATURES IS CONDUCTED. THE POSSIBILITY OF CORRELATING THESE CHANGES TO THE PROPERTIES OF FLOW AND LINEAR THERMAL EXPANSION, WHICH WERE CALCULATED EXPERIMENTALLY WITHIN THE SAME TEMPERATURE RANGE, IS ALSO EXAMINED. THREE DENTAL MODELLING WAXES WERE USED, AS WELL AS BEESWAX AND A WAX COMPOSED IN THE LABORATORY. IT WAS FOUND THAT ALL THE MATERIALS, SUBJECTED TO THE KINETIC STUDY OF DEFORMATION HAD UNDERGONE SHAPE-CHANGES, ESPECIALLY AFTER HEATING AT 27 C AND 47 C. THE FLOW VALUES MEASURED ARE RELATED TO THE CORRESPONDING SHAPE CHANGES. ON THE CONTRARY THE LINEAR EXPANSION OF THE MATERIALS DO NOT SEEM TO AFFECT THEIR BEHAVIOUR DURING THE KINETIC DEFORMATION STUDY. AT LOW INITIAL TEMPERATURES (27 C) THE DISTORTION OF THE SAMPLES IS MOST PROBABLY THE RESULT OF THE RELEASE OF INTERNAL STRESSES INTRODUCED DURING THE MANIPULATION OF THE WAX.ΣΤΗΝ ΕΡΓΑΣΙΑ ΑΥΤΗ ΠΑΡΟΥΣΙΑΖΕΤΑΙ ΜΙΑ ΚΙΝΗΤΙΚΗ ΜΕΛΕΤΗ ΤΩΝ ΜΕΤΑΒΟΛΩΝ ΤΟΥ ΣΧΗΜΑΤΟΣ ΤΩΝ ΚΕΡΙΩΝ ΟΔΟΝΤΟΣΤΟΙΧΙΩΝ ΜΕΤΑ ΤΟ ΧΕΙΡΙΣΜΟ ΤΟΥΣ ΣΕ ΔΙΑΦΟΡΕΣ ΘΕΡΜΟΚΡΑΣΙΕΣ. ΕΞΕΤΑΖΕΤΑΙ ΕΠΙΣΗΣ Η ΕΝΔΕΧΟΜΕΝΗ ΣΥΣΧΕΤΙΣΗ ΑΥΤΩΝ ΤΩΝ ΜΕΤΑΒΟΛΩΝ ΜΕ ΤΙΣ ΤΙΜΕΣ ΤΩΝ ΙΔΙΟΤΗΤΩΝ ΤΗΣ ΡΕΥΣΤΟΤΗΤΑΣ ΚΑΙ ΤΗΣ ΓΡΑΜΜΙΚΗΣ ΔΙΑΣΤΟΛΗΣ, ΠΟΥ ΜΕΤΡΗΘΗΚΑΝ ΠΕΙΡΑΜΑΤΙΚΑ ΣΤΗΝ ΙΔΙΑ ΠΕΡΙΟΧΗ ΘΕΡΜΟΚΡΑΣΙΩΝ. ΕΚΤΟΣ ΑΠΟ ΚΕΡΙΑ ΟΔΟΝΤΟΣΤΟΙΧΙΩΝ ΤΟΥ ΕΜΠΟΡΙΟΥ, ΧΡΗΣΙΜΟΠΟΙΗΣΑΜΕ ΚΑΙ ΚΕΡΙ ΜΕΛΙΣΣΩΝ, ΚΑΘΩΣ ΚΑΙ ΚΕΡΙ ΠΟΥ ΠΑΡΑΣΚΕΥΑΣΑΜΕ ΣΤΟ ΕΡΓΑΣΤΗΡΙΟ ΟΔΟΝΤΙΚΗΣ ΚΑΙ ΑΝΩΤΕΡΑΣ ΠΡΟΣΘΕΤΙΚΗΣ ΤΟΥ ΑΠΘ. ΔΙΑΠΙΣΤΩΣΑΜΕ ΟΤΙ ΟΛΑ ΤΑ ΥΛΙΚΑ ΠΑΡΟΥΣΙΑΣΑΝ ΜΕΤΑΒΟΛΗ ΤΟΥ ΣΧΗΜΑΤΟΣ ΤΟΥΣ, ΕΙΔΙΚΑ ΜΕΤΑ ΑΠΟ ΘΕΡΜΑΝΣΗ ΣΕ ΘΕΡΜΟΚΡΑΣΙΑ 27 ΚΑΙ 47 C. ΟΙ ΤΙΜΕΣ ΡΕΥΣΤΟΤΗΤΑΣ ΠΟΥ ΠΑΡΟΥΣΙΑΣΑΝ ΤΑ ΥΛΙΚΑ ΜΠΟΡΟΥΣΑΝ ΠΡΑΓΜΑΤΙ ΝΑ ΣΥΣΧΕΤΙΣΘΟΥΝ ΜΕ ΤΙΣ ΑΝΤΙΣΤΟΙΧΕΣ ΤΙΜΕΣ ΠΑΡΑΜΟΡΦΩΣΗΣ. ΑΝΤΙΘΕΤΑ, Η ΜΕΛΕΤΗ ΤΩΝ ΓΡΑΜΜΙΚΩΝ ΜΕΤΑΒΟΛΩΝ ΕΔΕΙΞΕ ΟΤΙ ΑΥΤΕΣ ΔΕΝ ΕΠΗΡΕΑΖΟΥΝ ΤΗ ΣΥΜΠΕΡΙΦΟΡΑ ΤΩΝ ΥΛΙΚΩΝ ΚΑΤΑ ΤΗΝΚΙΝΗΤΙΚΗ ΤΗΣ ΠΑΡΑΜΟΡΦΩΣΗΣ. ΣΕ ΧΑΜΗΛΕΣ ΑΡΧΙΚΕΣ ΘΕΡΜΟΚΡΑΣΙΕΣ ΦΑΙΝΕΤΑΙ ΟΤΙ Η ΜΕΤΑΒΟΛΗ ΤΟΥ ΣΧΗΜΑΤΟΣ ΤΩΝ ΥΛΙΚΩΝ ΥΠΑΓΟΡΕΥΕΤΑΙ ΑΠΟ ΦΑΙΝΟΜΕΝΑ ΑΠΕΛΕΥΘΕΡΩΣΗΣ ΕΣΩΤΕΡΙΚΩΝ ΤΑΣΕΩΝ

The influence of mixing methods and disinfectant on the physical properties of alginate impression materials.

Item does not contain fulltextThe aims of this in vitro study were to quantify the effect of manual versus automatic mixing and of using a disinfectant on mechanical properties of three different alginate impression materials. Two of the three alginates tested were especially developed for orthodontic use: Orthotrace(R) and Orthofine(R) while the third was a conventional alginate CA37FS(R). Alginates were mixed by hand or automatically using a Cavex alginate mixer II(R). Mixing was performed at room temperature using tap water. The material was allowed to set in a water bath at 35 degrees C (+/-1 degrees C), simulating intra-oral setting conditions, and half of the samples were disinfected before testing. For each tested material, 10 standardized samples were used. The disinfectant used was the CavexImpreSafe(R) that has a bactericide, virucide, and fungicide function. The specimens were exposed for 3 minutes in a 3% solution and were then tested according to the ISO 1563: 1990 (E) standard specifications. Descriptive statistics and three-way analysis of variance were performed, and a 5% significance level was used for statistical analysis. Evaluation of tensile strength and elastic recovery of different alginate samples, hand versus automatical mixing or disinfected versus not disinfected, resulted in significant differences for all materials except for Orthofine(R). Considering detail reproduction, all three alginates evaluated reproduced the 50-mum line successfully without interruption. The mixing method can significantly affect the elastic recovery and tensile strength of the alginates tested while the effect of using a disinfectant is less explicit.1 juni 201