title: The influence of tip geometry and distance on light-curing efficacy.
abstract: This study investigated the influence of the light guide shape on the polymerization efficacy of a light-activated resin-based composite cured with LED units as a function of the distance between the tip and the restoration. Two different LED units, each with different light guides and shapes, were used. Their ability to cure a single restorative material was investigated. The efficacy of the light-curing system was evaluated by measuring the depth of cure using the Acetone Shake test. Considering the ratio (R) between the entry diameter and the exit diameter of the light guide, the tips with a higher R-value proved to be more efficient if the tip and composite distance (D) was less than 5 mm, while for D > 5 mm, the tips with a lower R-value showed better results. The tip geometry of the tested light guide had a significant influence on the depth of cure of the tested resin composites. Therefore, depending on the distance, the more suitable light guide should be selected, based on the clinical situation. An R-value may be a better descriptor for the light guide shape than words such as "normal" or "turbo."
authors.affiliation: Department of Dental Materials, School of Dentistry, University of Siena, Siena, Italy. Gabriele.corciolani@gmail.com
authors.forename: Gabriele
authors.initials: G
authors.lastname: Corciolani
authors.forename: Alessandro
authors.initials: A
authors.lastname: Vichi
authors.forename: Carel Leon
authors.initials: CL
authors.lastname: Davidson
authors.forename: Marco
authors.initials: M
authors.lastname: Ferrari
mesh_terms: D003188:Composite Resins / Q000737:chemistry* / Q000528:radiation effects; D003764:Dental Materials / Q000737:chemistry* / Q000528:radiation effects; D003793:Dental Restoration, Permanent / Q000295:instrumentation*; D004867:Equipment Design; D006801:Humans; D008027:Light; D008029:Lighting / Q000295:instrumentation*; D008422:Materials Testing; D011108:Polymers / Q000737:chemistry / Q000528:radiation effects; D013053:Spectrophotometry; D013499:Surface Properties
chemical_list: D003188:Composite Resins; D003764:Dental Materials; C474035:Filtek Supreme; D011108:Polymers