A clinical evaluation of polishing amalgams immediately after insertion: 18 month results.

Thirty-three patients, 7-13 years of age, demonstrated 96 pairs of contralateral occlusal fissure a_~d buccal and lingual pit cavities which were restored with a high-copper amMgam. One restoration of each pair was polished with a slurry of XXX Silex in an unwebbed rubber cup at eight minutes following trituration. The contralateral restoration was finished at least 24 hours after iasertion with pear-shaped finishing burs and polished with a slurry of XXX Silex, followed by a slurry of tin oxide. Each restoration was examined clinically for five criteria by three examiners and black and white photographs were taken at baseline and at each six-month recall.appointment for 18 months. Clinically, marginal adaptation worsened from baseline to 18 months with both methods of polishing, but there was no significant differences between the two methods. However, a significant difference in marginal adaptation was evident by photographic evaluation. The surface textureof eight-minute polished restorations at baseline was granular compared to the glossy surface of restorations polished at 24 hours, but by 18 months, the surface texture of the restorations poh’shed by the two methods was very similar. marginal adaptation, reduced surface tarnish and marginal corrosion, and smoother surfaces and margins which are less susceptible to plaque accumulations."5 At least a 24-hour delay following insertion has been considered as the minimum period for conventional-amalgams to attain adequate physical properties before such restorations could be polished effectively. The faster setting time and the earlier rate of development of high compressive strength of the newer "high copper" dental amalgams support the possibility that earlier finishing and polishing may be possible without significant detriment to the final restoration. 6s While few clinicians appear to dispute the merits of finishing and polishing of amalgam restorations, the most practical time following placement remains unresolved. It is the purpose of this investigation to compare clinically the effects of early polishing of "high copper" dental amalgam restorations at an interval of eight minutes following the trituration of the amalgam with those observed after finishing and polishing at the more conventional time of at least twenty-four hours. Perhaps the greatest challenge to the longevity of amalgam restorations is observed in children in the primary, mixed, and young permanent dentitions. During such periods, when dynamic changes in the developing occlusion and peaks in caries activity are characteristic, the majority of decayed primary and young permanent teeth are restored with amalgam. Failures of such amalgam restorations are generally due to faulty cavity design, improper manipulation of the amalgam, or inadequate physical properties of the amalgam which lend to poor marginal adaptation and significant potential for recurrent decay. Benefits reported for the well-finished and polished amalgam restoration include improved Methods and Materials Thirty-three patients, age 7-13 years, who demonstrated a total of 66 contralateral pairs of Class I occlusal cavities and 30 contralateral pairs involving buccal or lingual pits or grooves were selected. Mesio-occlusal and disto-occlusal surfaces on the maxillary molars were considered as separate pairs, but were designated for the same polishing variable in the study due to problems of isolation of the polishing agents in a small area. The restorations were designated for either immediate polishing at eight minutes or polishing at 24 hours after the start of trituration by following a randomized numerical chart for right or left and then adjusting for the last 98 EARLY POLISHING OF AMALGAMS: Corpron et al, pairs in order to obtain equal numbers of right and left immediate-polish pairs. Selected teeth were anesthetized with 2% Carbocaine (Mepivacaine) containing 1:20,000 Neo-Cobefrin vasoconstrictor, isolated with a rubber dam, and Class I occlusal preparations were performed by three operators with a #56 fissure bur utilizing a high speed handpiece. Deep caries were removed with the appropriate size round bur in a contra-angle slow speed handpiece. The cavity was refined with a #57 fissure bur in a slow speed. After debridement of the cavity, varnish was applied with a smallcotton pellet. The amalgam was triturated with an S.S. White Capmaster amalgamator? according to manufacturer’s specification for regular set Tytin amalgam b (800 mg}. Condensation of the amalgam was mainly accomplished with a 1.4 mm round condenser and overpacked with a 1.4 mm x 2.0 mm elliptical shaped condenser using hand pressure. Carving Procedure Immediately following condensation, the amalgam was burnished with a #21B anatomical burnisher c and carved with the cleoid end of a 7C cleoid/discoid carver d for good definition of the enamel-amalgam margin and occlusal pattern. A 5C cleoid/discoid carver ° and an S.S. White #3 explorer f were used for refinement and for removal of flash at the margin. All amalgams were packed and carved during an interval of eight minutes from the start of trituration of the amalgam. Polishing Technique Marginal adaptation, anatomic form, surface texture, occlusai morphology and recurrent caries were selected as the criteria to clinically compare the two methods of finishing and polishing utilized in this investigation. The first method of polishing was accomplished at the operative appointment eight minutes from the start of trituration of the amalgam for one restoration of each pair. A creamy paste of Silex XXXg and water on an unwebbed black rubber cup in a slow speed contra-angle handpiece was applied to the tooth for a period not to exceed one minute per surface. The second method was designated that the other contralaterally paired tooth be finished and polished after twenty-four hours. Pear-shaped finishing burs of decreasing size were run along the enamel-amalgam margin utilizing slow speed. Grooves were refined with a #0 round finishing bur by carrying the bur from the enamel-amalgam as.s. White Division of Pennwalt Corp., King of Prussia, PA. bS.S. White Dental Products International, Holmdel, NJ. c d eE. F. Wessler Manufacturing Co., Cleveland, OH. fS. S. White Division of Pennwalt Corp., Philadelphia, PA. gMoyco Industries, Inc., Philadelphia, PA. margin into the center of the amalgam. Any extremely small grooves were finished with a #0 flameshaped bur. The amalgams were then highly polished with a creamy paste of XXX Silex and water on an unwebbed black rubber cup with slow speed, followed by a creamy paste of tin oxide h and water. Evaluation Evaluation of the two techniques of finishing and polishing amalgam was accomplished by two methods. The first method of analysis was a clinical examination based upon a Modified Ryge Explorer examination?" A qualitative visual clinical assessment was made utilizing a #4 mirror and an S.S. White #3 explorer by the three independent evaluators. The criteria for evaluation included: margin adaptation, anatomic form, surface texture, occlusal morphology, and caries (Tables 1-3). The teeth were examined at the baseline examination (at Table 1. Criteria for quality evaluation. Marginal Adaptation (Dry) Restorative material is continuous with adjacent tooth structure -not detectable with a sharp explorer, passes in either direction Margin detectable by explorer examination only -along less than 50% of exposed margin Margin detectable by explorer examination only -along more than 50% of exposed margin Visible evidence of crevice formation into which the explorer will penetrate along less than 50% of exposed margin Visible evid6nce of crevice formation into which the explorer will penetrate along more than 50% of exposed margin Crevice formation with exposure of underlying dentin or base Health Modified Center Ra ring Criteria