ABSTRACT
Statement of the Problem: The purpose of placing sealants is to inhibit caries by physical closure of the pits and fissures of teeth. A device named DIAGNOdent is useful in detecting occlusal caries by employing laser fluorescence [LF]. However, there are contradictory results in the influence of sealants on LF measurements
Purpose: The aim of this study is to investigate the effects of two different types of fissure sealants on LF measurements
Materials and Method: In this in vitro study, 86 extracted permanent third molars were divided randomly into two groups and clear or opaque sealant was applied on the occlusal surfaces. Two examiners performed pre- and post-seal fluorescence measurements twice with one week interval by employing DIAGNOdent device. Finally, measured values were evaluated through the statistical paired t-test by means of SPSS 17 software
Results: The mean value of LF measurements increased significantly due to the application of clear sealant [p= 0.001] while the statistical changes in this measurement was negligible after applying opaque sealant [p= 0.311]
Conclusion: Clear sealants increase the LF measured values but opaque sealants cause almost no changes. Therefore, DIAGNOdent device is not reliable for detecting caries beneath the clear sealant
ABSTRACT
A dressing often covers the wound to accelerate its healing. Hydrocolloid-type dressing to give better conditions for healing has been developed consisting of gelatin, pectin, water and hydrophilic polymer which promote healing. In recent years, much attention has been focused on the research and development of polymer hydrogels as biomaterials, such as contact lenses, wound dressing and drugdelivery systems. Hydrogels, as wound dressing were prepared with composite poly [N-vinyl-2-pyrolidone] [PVP] with several additives such as agar and polyethylenglycol [PEG] and by electron-beam. Electron beam was applied as a tool for initiation of crosslinking and sterilization of these materials. The effects of irradiation dose at the range of 10-40 KGy and various concentration of components on the characterizes of hydrogel such as gel content, degree of swelling [DS], equilibrium water content [EWC] and dehydration properties, transparency and microbial test were investigated. After irradiation, the achieved gel content of hydrogels was obtained higher than 25%. Gels' degree of swelling with different concentrations was changed from 35 to 20 at the range of irradiation dose of 10-40 KGy. Also, at the same range of irradiation and concentration, EWC of gels was found to be 98 to 94%. The dehydration results did not show variation with the tested parameters. Results showed that hydrogels membrane with composition PVP [10% w/w], agar and PEG [1-3%w/w] at the dose of 25 KGy had the amount of gel content 80-85%. Their DS and EWC were respectively obtained 30% and 96.5%. They were elastic, transparent, flexible, sterile and impermeable for bacteria. They absorbed a high capacity of water, attached to healthy skin, and they were easy to remove. It was concluded that the network was solely composed of crosslinked PVP plasticized by other compounds