Retention of composite resin restorations in class IV preparations.
Clinicians often utilized composite resin restorations in combination with different types of preparation to restore class IV fractures on anterior incisors. A new preparation technique called (stair-step chamfer technique) is investigated in this study to detect bond strength to tooth structure. Eighty-eight bovine teeth were divided into 4 groups. Group I had twenty-three samples with a 45 degree bevel that extended 2 millimeters beyond the fracture line. Group II had twenty-three samples with a circumferential chamfer, which extended 2 mm beyond the fracture line and half the enamel thickness in depth. Group III had twenty-three samples with a facial stair-step chamfer, which followed the anatomical contour and extended 2 mm beyond the fracture line with a lingual plain chamfer. Group IV had eighteen samples as controls, which were untreated teeth. The first three groups were prepared and restored with hybrid composite resin in conjunction with a single step bonding agent and as surface penetrating sealer, then tested for shear-bond strength on the Instron machine. The results were that there was no significant difference found between the treated teeth when tested for shear-bond strength. However, according to the site of the fracture, the stair-step chamfer technique gave significantly better results. It can be concluded that, the stir-step chamfer technique provides the clinician better environment to place a composite resin restoration resulting in good shear-bond strength and better esthetics.
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Hani
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Pediatric Dentistry Department, Tufts University School of Dental Medicine, Boston, MA 02111, USA.
D000134:Acid Etching, Dental; D000704:Analysis of Variance; D000818:Animals; D002417:Cattle; D016009:Chi-Square Distribution; D003188:Composite Resins / Q000737:chemistry*; D001840:Dental Bonding; D003737:Dental Cavity Preparation / Q000145:classification*; D003743:Dental Enamel / Q000293:injuries / Q000473:pathology; D003793:Dental Restoration, Permanent / Q000145:classification*; D017220:Dentin-Bonding Agents / Q000737:chemistry; D004955:Esthetics, Dental; D007180:Incisor / Q000293:injuries; D008689:Methacrylates / Q000737:chemistry; D013314:Stress, Mechanical; D014082:Tooth Fractures / Q000145:classification / Q000628:therapy
D003188:Composite Resins; D017220:Dentin-Bonding Agents; C420130:Excite cement; D008689:Methacrylates; C121818:Tetric ceram