The purpose of this study was to investigate the amount of residual monomer in a composite resin after light-curing with different sources, light intensities and spectra of radiation. The resin specimens (4 mm in diameter; 2 mm thick) (n=5) were inserted in Plexglass matrixes and light-cured with a halogen lamp, LED and PAC units for 40, 40 and 5 s, respectively. The polymerized specimens were ground and 25 mg of each specimen were immersed in 8 mL 96% ethanol for 24 h to extract the residual monomer. The amount of residual monomer was determined by the standard straight line method. The light spectrum of the different LCUs was shot and processed through researches of the absorbation of the standard solutions at a level of lambda=275 nm and their extracts. Data were analyzed statistically by variational dispersion analysis and Tukey-Kramer test at 5% significance level. It was observed that, the halogen lamp produced the smallest amount of monomer under sufficient light intensity. The spectrum of light radiation of PAC was within the limits of 450- 490 nm and was of extremely high intensity. This imposes the use of short-limited light impulses, but also might lead to deterioration quality of polymerization. The LED unit had the best spectral radiation. An increase of light intensity was proved necessary.
Dental fluorosis changes the colour and/or structure of enamel, leading to an unaesthetic appearance. One of the main goals in the treatment is aesthetic improvement of the affected teeth. Two clinical cases of patients with white spot fluorosis lesions on frontal teeth are presented. All treated teeth are infiltrated with low-viscous light-curing resin (ICON, DMG). A significant improvement in the aesthetic appearance of all the treated tooth surfaces is visible immediately after resin infiltration, and in most of the teeth - a complete disappearance of the white spots. Resin infiltration is an alternative micro-invasive approach for treatment of white spot lesions of different origin. It allows a quick and natural recovery of the affected teeth.
Citation: Georgiev KG, Filipov IA, Dobrev IN. In vivo collection and SEM identifi cation of oral biofi lm using indirect composite prototype restorations. Clinical and laboratory study. Folia Med (Plovdiv) 2018;60(2):300-7.Background: The oral ecosystem is a dynamic environment inhabited by more than 700 microbial taxa. Recent studies report that multispecies oral biofi lms develop on the surface of resin composites leading to degradation of its organic matrix and altered structural stability of the restoration. Aim: To examine the effi cacy of a novel clinical approach to investigating in vivo formed biofi lms on resin composite surfaces.
Materials and methods:The clinical protocol of this study implemented indirect composite molar restorations (from resin material Filtek Z250, 3M ESPE) as intraoral biofi lm carriers (test devices). We recruited for the experiment 5 consenting adult subjects with indications for indirect molar restoration. For each subject we fabricated 4 indirect restorations, 3 of which dedicated to diff erent intraoral duration -3, 7, and 14 days. All composite carriers were fi xed temporarily for the intended time period and consecutively replaced. The detached carriers were prepared for microscope analysis at each time interval. The fourth composite carrier was used as the defi nitive restoration. Results: The timeline of the biofi lm formation and the microbial morphology were associated with previous studies of in vivo bacterial colonisation. A correlation between the plaque formation cycle and the DMFt indices of the subjects was established.
Conclusions:The implementation of indirect composite restorations as intraoral biofi lm carrier off ers valuable contribution to the real time investigation of in vivo biofi lm accumulation.
BACKGROUND
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