title: Ultra-violet absorption by two ultra-violet activated sealants.
abstract: Since the ability of u.v. setting pit and fissure sealants to set in depth is dependent on the penetration of the u.v. radiation, the absorption coefficients of Nuva-seal and Alphaseal were determined at 365 nm, the wavelength of radiation used to polymerise both materials. Nuva-seal and Alphaseal had absorption coefficients of 0.165 mm-1 and 6.25 mm-1, respectively. The u.v. fluorescent dye present in Alphaseal contributed 2.5 mm-1 to its absorption coefficient and the remaining absorption was due to the 5% w/w catalyst concentration present, since the basic resin had no significant absorption. Therefore Nuva-seal may set adequately to the depths required of fissure sealants, but Alphaseal may not, unless a very high intensity u.v. source is used. A reduction in the catalyst concentration and the removal of the u.v. fluorescent dye might improve the setting characteristics of Alphaseal.
mesh_terms: D000327:Adsorption; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D004396:Coloring Agents; D003764:Dental Materials; D010895:Pit and Fissure Sealants; D011108:Polymers; D013499:Surface Properties; D014466:Ultraviolet Rays
chemical_list: D004396:Coloring Agents; D003764:Dental Materials; D010895:Pit and Fissure Sealants; D011108:Polymers