A comparison of two dentin bonding agents in primary and permanent teeth.

The shear bond strengths of 2 dentin bonding techniques were tested on primary and permanent teeth. No significant differences were noted between the mean bond strengths for primary and permanent teeth or between the Scotchbond® Dental Adhesive System and a method utilizing ferric oxalate, NTG-GMA, and PMDM. Microscopic examination revealed that the majority of bond failures occurred at the dentin-resin interface. Methods and Materials Twenty noncarious human primary molars and 20 noncarious human maxillary third molars were embedded in copper tubes which had been filled with improved dental stone. The teeth were placed in the stone so that the clinical crowns remained exposed. An engraver pantograph a was used to expose flat surfaces of dentin on the buccal, lingual, distal, and mesial surfaces of the teeth (Fig 1). Three of the surfaces of each tooth were selected for resin application by a random allocation method. Three techniques were investigated as dentinal adhesives including: (1) a control consisting of an unfilled composite resin b applied to untreated dentin; (2) Bowen’s method using ferric oxalate, NTG-GMA, and PMDM; 1,2 and (3) the Scotchbond c dental adhesive. The ferric oxalate, NTG-GMA, and PMDM solutions used in the Bowen technique were prepared as Model P1-3 -Gorton Machine Corp: Racine, WI. Silux Enamel Bond resin -3M Dental Products: St Paul, MN. Scotchbond Dental Adhesive System -3M Dental Products: St Paul, MN. suggested by Bowen et al. 3 The solutions were stored in amber-colored glass bottles until used. The control resin was applied to dentin which had been cleaned using a pumice-water slurry. The ~erric oxalate, NTG-GMA, and PMDM solutions used in the Bowen technique were applied to the dentin, surfaces following the technique suggested by Bowen et al. 3,4 (Table 1). The Scotchbond adhesive was applied to dentin surfaces which had been cleaned using a pumice-water slurry according to the manufacturer’s directions. Following applications of each dentinal bonding material (and after cleaning in the case of the control resin) a large elastic separator d was placed on the dentin surface and filled with a light-cured composite resin b (universal shade) to form a resin "button." The resin button was polymerized for 20 sec using a standard light source, e Bond strengths of the materials were determined in the shear mode using a testing machined A 500kg load cell was used in the testing machine with a 10-kg full scale range and a crosshead speed of 0.15 cm/min. Microscopic examination was used to evaluate several of the specimens before and after preparation of the dentin surfaces and following shear testing. Upon completion of the initial data collection, new information became available concerning the preparation of the chemicals used in the Bowen technique. New solutions of ferric oxalate, NTG-GMA, and PMDM were prepared based on the new recommendations of Bowen and Cobb5 as follows: (1) ferric oxa GAC International: Commack, NY. * Prisrna Lite, Model PR-1 -LD Caulk Co: Milford, DE. f Instron Universal Testing Machine -Instron Corp: Canton, MA. 144 DENTIN BONDING AGENTS/COMPARISON: Eagan et al. FIG 1. Engraver pantograph exposing flat surfaces of dentin on the buccal, lingual, distal, and mesial surfaces on a tooth embedded in stone in a copper tube. TABLE 1. Technique for Application of Ferric Oxalate, NTCCMA, and PMDM 1. Apply a drop of ferric oxalate solution for 60 sec. 2. Distilled water rinse for 10 sec. 3. Blow surface with air for 10 sec. 4. Apply 1 drop NTG-GMA for 10 sec. 5. Remove excess solution with a cotton swab. 6. Apply 1 drop acetone for 10 sec. 7. Remove excess solution with a cotton swab. 8. Blow surface with air for 10 sec. 9. Apply a drop of PMDM solution for 60 sec. 10. Blow surface with air for 10 sec. 11. Place composite material and polymerize. alate was prepared under safelight conditions; (2) the NTG-GMA acetone solution was stored anaerobically; and (3) the NTG-GMA solution was used the day following its preparation. Unused proximal surfaces on the 10 permanent molars that had been used in the first experiment were reprepared on the engraver pantograph so as to expose fresh dentin surfaces. The new solutions of ferric oxalate, NTG-GMA, and PMDM were applied to the dentin surfaces and a resin button was placed following the same technique used in the first study. These specimens then were subjected to shear testing as previously described.