title: Influence of eugenol-containing temporary restorations on bond strength of composite to dentin.
abstract: This study investigated the influence of eugenol-containing temporary restorations on bond strength of composite to dentin. Thirty-two freshly extracted human molars were embedded and horizontally sectioned at a level 2 mm from the central fossa to obtain a flat dentin surface. The teeth were randomly divided into four groups of eight teeth. Specimens in Group 1 (control) received no pre-treatment with any temporary restorations. Group 2 and 3 specimens were covered with IRM (eugenol-containing) mixed at powder: liquid (P:L) ratio of 10 g: 1 g and 10 g: 2 g, respectively. Specimens in Group 4 were covered with polycarboxylate cement (eugenol-free) mixed at a P:L ratio of 2.85 g: 1 g. The temporary restorations were mechanically removed with an ultrasonic scaler after one-week storage in distilled water at 37 degrees C. The dentin surfaces were cleaned with pumice-water slurry and treated with Scotchbond Multi-Purpose Plus bonding system according to manufacturer's instructions. Composite (Z100) columns (3 mm diameter, 2 mm high) were applied and shear bond testing was carried out after 24 hours storage in distilled water at 37 degrees C using an Instron Universal testing machine with a cross-head speed of 0.5 mm/minute. The mode of failure was examined using a stereomicroscope at X40 magnification. Results were analyzed using one-way ANOVA/Scheffes's post-hoc test at significance level 0.05. Ranking of bond strengths was as follows: Group 1 (22.58 MPa) > Group 2 (21.14 MPa) > Group 4 (15.35 MPa) > Group 3 (13.02 MPa). Group 3 had significantly lower bond strength than Groups 1 and 2. No significant difference in dentin bond strength was observed between the Group 1 (control) and Groups 2 and 4. Although the predominant mode of failure for Groups 1, 2 and 4 was cohesive in dentin, all specimens in Group 3 exhibited adhesive failure. Pre-treatment with polycarboxylate cement or IRM mixed at P:L ratio of 10 g: 1 g did not affect shear bond strength of composite to dentin. IRM mixed at a lower P:L ratio of 10 g: 2 g significantly decreased bond strength.
authors.affiliation: Department of Restorative Dentistry, Faculty of Dentistry, Centre for Biomedical Materials Applications and Technology, Faculty of Engineering, National University of Singapore, Singapore.
authors.forename: A U
authors.initials: AU
authors.lastname: Yap
authors.forename: K C
authors.initials: KC
authors.lastname: Shah
authors.forename: E T
authors.initials: ET
authors.lastname: Loh
authors.forename: S S
authors.initials: SS
authors.lastname: Sim
authors.forename: C C
authors.initials: CC
authors.lastname: Tan
mesh_terms: D000704:Analysis of Variance; D003188:Composite Resins; D001840:Dental Bonding; D019232:Dental Restoration Failure; D003794:Dental Restoration, Temporary; D003804:Dentin; D017220:Dentin-Bonding Agents; D005054:Eugenol; D005899:Glass Ionomer Cements; D006801:Humans; D008768:Methylmethacrylates; D008964:Molar, Third; D011897:Random Allocation; D019279:Resin Cements; D012822:Silicon Dioxide; D018709:Statistics, Nonparametric; D015035:Zinc Oxide-Eugenol Cement; D015040:Zirconium
chemical_list: D003188:Composite Resins; D017220:Dentin-Bonding Agents; D005899:Glass Ionomer Cements; D008768:Methylmethacrylates; D019279:Resin Cements; C425844:Scotchbond Multi-Purpose Plus; C083568:Z100 composite resin; D015035:Zinc Oxide-Eugenol Cement; C062270:Shofu Hybond; D005054:Eugenol; C031667:IRM cement; D012822:Silicon Dioxide; D015040:Zirconium