APRIL 1977 VOL. XXXVI NO. 4 50¢ 36TH YEAR OF PUBLICATION \"'. II I -- I I 6W."'~~ ttttt , IIG, one of the most readable, award-winning dental " '" Ildlltt!!'I' I j magazines in America, comes to you, doctor, as a professional courtesy of your l'iconium Laboratory. 111111;111111111111111111111;11111111111111111111111111IIIIIIIillllllllllllllllllllili rUHYARO l DENTISTRY SCORES WITH BASEBALL 5. Kanai, S. - Structure studies of amalgam, - II. Effect 10. Teixeira, L. C. - Dental amalgam: effect of burnishing of burnishing on the margins of occlusal amalgam fillings. on the hardness of the margins. Thesis for the doctor Acta Odont. Scand., 24:47-53,1966. degree, 1973. 6. Jorgensen, K. D. and Saito, T. - Structure studies of 11. Central Regional Meeting of Operative Dentistry, Creigh­ amalgam-V. The marginal structure of occlusal amal­ ton University, Omaha, Nebraska, February 6-7,1975. ATechnique for Improving the Amalgam Restoration gam fillings. Acta Odont. Scand., 25:235-45, 1967. 12. Kato, S.; Okuse, K. and Fusayama, T. - The effect of 7. Wilson, R.T.; Phillips, R. W. and Norman, R. D. -In­ burnishing of the marginal seal of amalgam restorations. J. Prosth, Dent., 19:393-8, 1968. fluence of certain condensation procedures upon the by Gerald E. Denehy, D.D.S., M.S. mercury content of amalgam restoration. J. Dent. Res., 13. Svare, C. W., and Chan, K. C. - Effect of surface treat­ 36:458-61,1957. ment on the corrodibility of dental amalgam. 1. Dent. and Luiz C. Teixeira, C.D., D.C. 8. Fusayama, T. et al. - Surface roughness of amalgam Res., 51:44-47,1972. fillings made by various technics. J. Dent. Res., 46:lO19- 14. Charbeneau, G. T. - A suggested technic for polishing 21, 1967. amalgam restorations. J. Mich. Dent. Ass., 47 :320-5, A malgam burnishing could be defined as the rub­ tion, where regardless of the method of condensation, bing of the surfaces of a freshly placed amalgam with the mercury concentration is higher. (7) 9. Nakai, H.; Ishizaki, N. and Nihei, I. - The mircrostruc­ 1965. ture and hardness of dental amalgam. J. Osaka Dent. LEGEND: Figure 4 and 5 - A-amalgam; E-enamel; arrow a metal instrument to produce a smooth shiny finish. Burnishing may also be considered a part of the Univ., 4:131-49,1970. -cavosurface margin orig. mag. 100x. For many years this procedure has been considered finishing procedure. The rough surface left by the detrimental to the finished amalgam restoration. (1·3) carving instrument is smoothed by the burnisher. (8) (Copyright by The Journal of the Indiana Dental Association. Reprinted by permission.) Current research studies have shown, however, that A shine is imparted to the restoration and later polish­ burnishing, rather than producing adverse effects, ing procedures are greatly simplified. definitely improves the physical properties of the I MISS MY FAVO FOUR-LETTER WORD amalgam restoration. (4·5·6·8·10) This has led to ac­ What Are the Benefits of ceptance of the technique to a degree that operative hy H. Marie Davis Burnishing an Amalgam? educators from the seven midwestern dental schools The major results of burnishing an amalgam are represented at a recent Central Regional Meeting of I'll probably never hear it again. He just doesn't say Why does it take only minutes for an anesthetic to best exhibited at the margins of the restoration. De­ Operative Dentistry unanimously agreed that amal­ it any more. My dentist, that is. And I miss it so­ deaden the jaw, and hours for it to wear off? It's al­ crease in residual mercury and gamma2 phase result that wonderful welcome four-letter word. most impossible, upon leaving the dentist's office, to gam burnishing was beneficial and should be included in harder margins. (9·10) Marginal seal has been shown But things have changed markedly in the more-than­ replenish your lipstick without jabbing it into your in the amalgam technique taught at the schools. (11) to improve with burnishing, reducing marginal leak­ twenty years that have passed since I started going to checkbone, orup your nose. age. (12) Corrodibility of amalgam surfaces has been him. Now his assistant puts that damnable miniature What used to take my dentist an hour to do, now What Changes Occur in the Amalgam significantly lowered in studies involving burnished sump pump in my mouth and leaves it there to hiss takes only half that time, because of his acquiring an Restoration during Burnishing? amalgams. (13) Also as previously stated, burnishing and gurgle away, on about five cylinders. assistant, and his updated dental equipment. And Amalgam burnishing may be considered a continua­ greatly reduces the need for extensive polishing pro­ Every few minutes, he pauses, at which point his probably for other reasons not generally known to the cedures. (14) tion of the condensation process. The unreacted gam­ assistant squirts a stream of water around, then swoops lay public. ma phase alloy particles ( Ag3Sn) arc brought closer it out with the tiniest vacuum cleaner ever seen. Slurp, Nevertheless, I sorely miss the satisfaction of lean­ How Should an Amalgam Be Burnished? squish, yuk, gag. Again, only about 75 percent satis­ ing forward every few minutes and enjoying a good, together, diminishing the amount of microporosity fying. No, I don't expect to ever hear my favorite four­ thorough, mouth-emptying SPIT! and the relative residual mercury content. (4,5) De­ Burnishing of an amalgam is accomplished by the letter word again-SPIT. 4215 N.E. 82 Street creasing the relative content of mercury in the amal­ rubbing with firm pressure of a smooth metal instru­ To compound the problem, from the patient's point Seattle, Washington 98115 gam results in a decrease of the matrix which is ment in a back and forth movement over the surface of view, he has tossed out his old, comfortable, composed of a mixture of gamma! (Ag2Hgg) and of the amalgam restoration. Although any smooth straight-backed dental chair, and replaced it with a gamma2 (Sn7.S Hg) phases. (6) As a result there is a metal instrument will accomplish this purpose, the modern, gorgeous, pastel reclining piece of furniture. decrease in the least desirable phase, gamma2. This ones which function most efficiently conform closely He declines it beyond the point of horizontal. The is particularly important at the margins of the restora- to the contour of the surface area to be burnished. head is actually lower than the feet so that the saliva This includes small ball burnishers for the occlusal tends to run down my throat faster than his handy­ grooves (Fig. 1), larger ball burnishers for occlusal dandy little swooper·outer can cope with it. (And I About the authors cavosurface areas (Fig. 2), and football shaped or learned early to wear only pants suits, not dresses, to Dr. Teixeira is Visiting Professor at the Department of Oper­ pointed burnishers for the proximal, inclined planes my dental appointments.) ative Dentistry, University of Iowa, College of Dentistry. or embrasure areas (Fig. 3). The back and forth It's not all bad, though. These modern intrusions Received his undergraduate dental degree and his doctor de­ movements should be overlapping and should result in gree from the University of San Paulo School of Dentistry, into the field of dentistry, have permitted him to speed a smooth shiny appearing surface. up the process. I have been placed in one room, in­ Ribeirao Preto, SP, Brasil, where he is a part-time Assistant Professor at the Department of Restorative Dentistry, School jected with novacaine, and had the dentist fill another of Dentistry, USP, Ribeirao Preto, SP, Brasil. patient's tooth in an adjacent room, in the time it takes When Should Amalgams Be Burnished? Dr. Denehy received his undergraduate dental degree from Exact times for initiating the burnishing of an amal­ for my novacaine to take effect. Just sitting there, Lama Linda University, School of Dentistry and his M.S. knowing what is coming next, and hearing his piped-in from the University of Iowa. Dr. Denehy is an Associate gam have not been clearly defined in the literature and music system playing what might as well be "Nearer Professor at the Department of Operative Dentistry, Univer­ there is confusion in the minds of many operators. My God To Thee," only stimulates the saliva flow. sity of Iowa, College of Dentistry, Iowa City, Iowa. Research studies have used burnishing times ranging 10 ~IC APRil, 917 T 77 1 Fig. 1 Fig. 6 Fig. 4 Fig. 5 What Are the Precautions in 4. Upon completion of burnishing, the cavosurface Burnishing an Amalgam? margin areas should be examined for flash which should be removed. If the flash is extremely thin, Perhaps more important than the exact burnishing a damp cotton pellet may be used, otherwise a time, is the immediate effect of burnishing on the con­ carver will be necessary. After flash removal, the tour of the amalgam restoration. If firm burnishing area should again be burnished. The finished bur­ procedures are initiated too early while the amalgam nished restoration should exhibit a smooth shiny is still soft, it is extremely easy to break-down the con­ surface. (Fig. 6) tour of the amalgam restoration and end up with an undercontoured restoration. This results in ditching of 5. After rubber dam removal, the amalgam should be the cavosurface margins or acute amalgam margins checked for occlusal interferences and adjusted which are easily fractured. (Fig. 4) accordingly. Those areas carved for occlusal ad­ Undercarving of an amalgam with the concept that justment should be burnished again. (Fig. 7) burnishing will remove the excess often results in flash 6.