title: Load-bearing capacity of direct four unit provisional composite bridges with fibre reinforcement.
abstract: The aim of the current in vitro study was to evaluate the load-bearing capacity of provisional four-unit bridges with and without two different types of glass-fibre reinforcement produced in a direct technique with a silicon template from the composite materials Protemp, Luxatemp and CronMix. From each composite material, 30 bridges were manufactured, 10 without fibre reinforcement, 10 with Stick/StickNet and 10 with everStick/everStickNet reinforcement. After artificial aging by thermocycling samples were cemented onto a master model and subjected to load testing in a universal testing machine. Mean force at fracture for the groups without fibre reinforcement varied from 486 to 612 N. Depending on the material combination, fibre reinforcement resulted in a slightly increased or a reduced mean load-bearing capacity, varying from 674 N for the combination of Protemp and Stick to 262 N for CronMix and everStick. Position of fibres within the resin pontic was found to have an important influence on load-bearing capacity of reinforced bridges. Scanning electron microscopic investigation showed good adhesion of everStick fibres to the pre-impregnation resin whereas bonding of Stick fibres to the embedding polymer was incomplete. In conclusion, fibre reinforcement with Stick or everStick did not improve the load-bearing capacity of direct provisional bridges made from Protemp, Luxatemp, or CronMix as the position of fibres could not be controlled during the direct manufacturing process. To increase the load-bearing capacity of the provisional bridges, an exact positioning of fibres at the tension side in the dental laboratory is necessary.
authors.affiliation: Department of Prosthetic Dentistry, Hannover Medical School, Hannover, Germany. eisenburger.michael@mh-hannover.de
authors.forename: M
authors.initials: M
authors.lastname: Eisenburger
authors.forename: J
authors.initials: J
authors.lastname: Riechers
authors.forename: L
authors.initials: L
authors.lastname: Borchers
authors.forename: M
authors.initials: M
authors.lastname: Stiesch-Scholz
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry; D000268:Adhesiveness; D017438:Bisphenol A-Glycidyl Methacrylate / Q000737:chemistry; D003188:Composite Resins / Q000737:chemistry*; D003799:Dental Stress Analysis / Q000379:methods; D003830:Denture, Partial, Fixed; D019544:Equipment Failure Analysis / Q000379:methods; D005898:Glass / Q000737:chemistry; D006801:Humans; D008422:Materials Testing / Q000379:methods; D008855:Microscopy, Electron, Scanning; D011474:Prosthesis Design; D016474:Weight-Bearing
chemical_list: D000180:Acrylic Resins; D003188:Composite Resins; C009753:fiberglass; C098586:luxatemp; D017438:Bisphenol A-Glycidyl Methacrylate; C069714:Protemp