Reduction of cusp deflection resulting from composite polymerization shrinkage, using a light-transmitting cone.
For investigation of whether the use of a transparent plastic cone (Light-tip) influenced cusp deflection, as compared with a conventional method (control), the following experiments were performed. Mesiodistocclusal (MOD) cavities were prepared in 10 extracted premolars, and stainless steel pins were placed on the cusps. The cavities were bonded with Scotchbond Multipurpose, and the distance between the pins was measured. Control restorations using P-50 were placed in three increments, each increment having been polymerized for 40 s. For placing the test restorations, the Light-tip was fitted to the end of the curing wand and pressed into the resin in the proximal box, and the curing light was turned on. The next increment filled the recess created after the removal of the cone in the resin, and curing was performed with the plastic cone in the occlusal box. The third increment was cured without the cone. Each tooth was used for four restorations. In 16 of 20 cases, a significantly decreased cuspal flexure was found when the cone was used. The flexure decreased 24%, as compared with control.
Ericson
D
D
Department of Cariology, Faculty of Dentistry, University of Lund, Malmö, Sweden.
Paulsson
L
L
Sowiak
H
H
Dérand
T
T
D001641:Bicuspid; D017438:Bisphenol A-Glycidyl Methacrylate; D003188:Composite Resins / Q000737:chemistry*; D003487:Cyanoacrylates / Q000737:chemistry; D001840:Dental Bonding / Q000295:instrumentation* / Q000379:methods; D003737:Dental Cavity Preparation; D003743:Dental Enamel / Q000033:anatomy & histology* / Q000502:physiology; D003793:Dental Restoration, Permanent; D017220:Dentin-Bonding Agents / Q000737:chemistry*; D006801:Humans; D008027:Light; D008434:Matrix Bands; D011108:Polymers / Q000737:chemistry; D019279:Resin Cements; D013193:Stainless Steel; D013314:Stress, Mechanical
D003188:Composite Resins; D003487:Cyanoacrylates; D017220:Dentin-Bonding Agents; D011108:Polymers; D019279:Resin Cements; C084018:Scotchbond Multi-Purpose; C065771:P50 composite resin; D013193:Stainless Steel; D017438:Bisphenol A-Glycidyl Methacrylate; C008424:methyl 2-cyanoacrylate