A clinical evaluation of polished and unpolished amalgam: 36-month results.

Twenty-six patients, 5-13 years of age, demonstrated 67 pairs of contralateral occlusal fissure and buccal, or lingual pit carious lesions which were restored with a spherical high-copper amalgam. One restoration of each pah" was allowed to remain as carved, while the other was finished and polished 24 hours after insertion. Each restoration was evaluated clinically by three independent examiners. Black and white photographs were taken at baseline, 6, 12, and 18 months for a comparative indirect evaluation. Clinically, margin adaptation became more detectable from baseline to 18 months for both restorations with no significant difference between the two methods of finishing, Photographically, marginal adaptation also deteriorated from baseline to 18 months, with significant difference from the previous evaluation at both 6 and 18 months, but no difference between the two methods. The surface texture was significantly different between the two methods at all recall evaluations. The development of high-copper dental amalgam has resulted in alloys with improved physical properties and handling characteristics as compared to conventional dental amalgams.1 These include improved marginal adaptation, increased resistance to surface corrosion, and lower static creep. It has been reported that marginal adaptation and resistance to surface corrosion have been enhanced by postinsertion finishing and polishing techniques.2-, The effects of finishing and polishing on marginal adaptation are disparate, commonly derived from laboratory studies which have reported that finished amalgam restorations demonstrated more regular margins compared to carvedonly restorations. However, following finishing and polishing, frequent marginal gaps have been reported between the amalgam and the enamel surface. 5-~ Richard E. Corpron, DDS, MS, PhD Susan H. Carron, DDS, MS The aim of this study was to compare high-copper amalgam restorations which were allowed to remain as carved with similar restorations that were finished and polished after a postinsertion period of at least 24 hours. Written criteria for marginal adaptation, anatomic form, surface texture, occlusal morphology, and caries were used to evaluate each restoration clinically. Marginal adaptation also was evaluated indirectly utilizing clinical photographs. Eighteen-month results are reported as part of a three-year clinical project. Methods and Materials Twenty-six patients (age 5-13 years) selected for this study demonstrated 50 contralateral pairs of permanent and primary molars with incipient occlusal caries, and 17 pairs with carious buccal or lingual pits. Following adminstration of local anesthesia and isolation of the appropriate teeth with a rubber dam, Class I cavities were prepared with a//56 fissure bur in a high-speed handpiece. Any deep caries was removed with an appropriate size round bur in a conventional-speed contra-angle handpiece. Pulp protection in deep cavity preparations was achieved using Dycal a as a liner, cavity varnishb to seal the dentin walls, and zinc phosphate cement basec to provide ideal cavity depth. The preparations were refined with a #56 bur at conventional speed. After debridement, a single coat of cavity varnishb was placed over all internal cavity walls and margins. Regular set Tytin amalgam in 800 mg Capsules a was triturated with an S.S. White Capmaster0 amalgamator for 6seconds and carried to the preparation, condensed and over-packed with a 1.4 x 2.0 mm elliptical condenser using hand pressure. The amalgam first was burnished " Dycal, L.D. Caulk Co.: Milford, Del. b Copalite, Cooley & Cooley, Ltd.: Houston, Texas. c Missy, Inc.: Clifton Forge, Va. a S.S. White Dental Products International: Holmdel, N.J. * S.S. White Division of Pennwalt Corp.: King of Prussia, Pa. PEDIATRIC DENTISTRY: Volume 5, Number 3 177 with a #21B anatomical burnisher~ and carved with a 7C discoid/cleoid carverf followed by a 5C carver.~ An S.S. White #3 explorers was used to refine and remove flash at the margins. All amalgams were packed and carved within 8 minutes of the start of trituration. From each pair, one restoration was selected randomly to be finished and polished after 24 hours while the other remained as carved. Initial finishing was done with a #6 or a #4 pear-shaped bur at conventional speed, and the grooves were refined with a #2 round finishing bur or a #0 flame-shaped bur. Each restoration selected was polished with a thin slurry of XXX Silex h at conventional speed and then a creamy mix of tin oxide. The amalgams were evaluated using modified criteria from Ryge9-12 for: marginal adaptation, anatomical form, surface texture, occlusal morphology, and caries ~2 at baseline and at each subsequent six-month recall appointment. Black and white photographs also were taken of each tooth at baseline and at six-month intervals using a camera with a 200 mm macrolens set at 1.5x. The black and white photographs then were enlarged to 6.4x for evaluation of marginal adaptation and flash. A modification of Mahler’s method of photographic evaluation for marginal adaptation13 was developed using six photographs of representative restorations, depictihg each of the modified criteria used for the clinical evaluation. 12 The amount of marginal overextension (flash) also was accessed photographically for each restoration.~2 A consensus was reached when at least two of the three examiners agreed independently on the same rating for each clinical and photographic evaluation. If no consensus occurred, the three examiners reviewed the clinical f E.F. Wessler Manufacturing Co.: Cleveland, Ohio. ~ S.S. White Division of Pennwalt Corp,: Philadelphia, Pa. h Moyco Industries, Inc.: Philadelphia, Pa. i Matheson, Coleman & Bell: Norwood, Ohio or photographic scoring in order to reach a consensus agreement. The values obtained from the ratings of the three examiners using the modified Ryge explorer examination were converted to corresponding ratings of the Dental Health Center rating scale. Interexaminer agreement was calculated for both methods to allow comparison.