OPERATIVE DENTISTRY, 1980, 5,107-114.
Direct Golds in Dental Restorative Therapy
GERALD D STIBBS
433 Medical-Dental Building, Seattle, WA 98101, USA
GERALD D STIBBS, BS, DMD, conducts a private practice part time and is professor emeritus of restorative dentistry at the University of Washington. He is mentor of three gold foil study clubs-the George Ellsperman Gold Foil Seminar, the Vancouver Ferrier Study Club, and the Walter K Sproule Study Club. He is a member of the American Academy of Gold Foil Operators, the Academy of Operative Dentistry, the American Academy of Restorative Dentistry, an honorary member of the Canadian Academy of Restorative Dentistry and a fellow of the American College of Dentists.
Presented at the essay session of the annual meeting of the Academy of Operative Dentistry, Chicago, 14 February 1980.
In addressing the important subject of "Direct Golds in Dental Therapy," there is so much to tell that the greatest problem is deciding on the best approach. Some of you are highly competent, enthusiastic, direct gold users. What can I tell you! Others have an aversion to these materials, or have had limited or no exposure to the procedures involved. I cannot make expert direct gold operators of you in the few minutes at our disposal. What I hope to do is whet your appetite so you will progress from your present point, and become more competent, and more enthusiastic about the service you can render.
REDUCED EMPHASIS ON DIRECT GOLD
Admittedly, there is now less emphasis on the direct golds than there was some time ago. Why?
In many of the dental schools this material receives less attention because:
VALUE OF DIRECT GOLDS
In spite of these adverse influences and circumstances, the direct golds still constitute one of the best of the available restorative materials, if- if-
1. They are used where indicated.
2. They are manipulated properly.
3. The operator has, or is willing to acquire, the necessary expertise.
G V Black once wrote, "No other material can be so worked against the walls of a cavity as to make full use of the sustaining power of the elasticity of the dentin" (1908). That still holds true.
As you know, pure gold is one of the oldest restorative materials, yet it is still the standard-bearer, or the yardstick, or, in today's parlance, the meter stick. Other materials are compared with foil, the other forms of gold are compared with foil, so we should know how and where to use it. While I am a long-time disciple of foil in dentistry, I also recognize that, if foil is not used correctly, it is one of our least successful procedures. I extol its virtues, but I also caution against anyone thinking that going through the technic once or twice, or reading a few papers on the subject will make him adept or even semi competent in its use. As W I Ferrier used to say. "it does not come by a 'laying on of hands."'
HOW TO LEARN THE PROCEDURE
For the benefit of you who have received limited coaching in the procedure, or who have not given it any thought or attention recently, let me give you a few pros and cons and outline the state of the art. I want you who are interested to know that you are not alone. I encourage you to follow your Inclination to use this excellent restorative medium.
There is a wealth of material in the literature, if you will take the time to look if up. It is fascinating reading. To assist you, a short list of representative articles to initiate or further your search is given at the end of this article. I could not be all-inclusive and have undoubtedly omitted some excellent presentations- In those listed you will find reference to other fine reports.
Instruments and Supplies
The second step in learning this technic is to assemble a basic kit of instruments and supplies (a list is available from the author) and a small amount of each type of gold. Such an introductory package is available from the manufacturer, Williams Gold Refining Co (2978 Main St, Buffalo, NY 14214, USA; 800/8281538). By trial and error, determine which one, or ones, best suit your needs, and go from there.
The third, and preferred, approach is to join an operating study club and, with the aid and guidance of the mentor or preceptor, develop your skills under his supervision. It will be the greatest thing you can do for your dental advancement, for improvement of your restorative service, and to stimulate your sense of accomplishment.
Each of us who talks about, and uses, direct golds acknowledges prime stimulus from one or other of the great operators who preceded us. Some of these leaders have been rather regional in their Influence; others have had a nationwide or worldwide Impact. Each, in his own way, has given unstintingly of himself, and we are all indebted to them.
The principal obstacles to the use of direct golds are:
1. The operator's lack of training and consequent lack of enthusiasm and comfort with the technic.
2. The patient's aversion to an unsightly display of metal.
3. Many carriers of denial insurance plans do not accept the direct golds, and the nondental adjudicator thus arbitrarily excludes our superior preventive restorative medium.
4. Concern of some dentists that the present cost of gold will price foil and gold alloys out of the market.
These objections can be met by the operator becoming familiar with a good, sound technic. by having the proper armamentarium, and by knowing the possibilities of restoration outlines that minimize or eliminate the display of metal.
As to the third-party encroachment, we can keep working to enlighten the bureaucracy and in the meantime resume the good, old-fashioned, direct relationship of patient to dentist, and do what is best for the dental health, regardless of outside political and financial pressures.
As to the cost, it is still a minor consideration. For example, when gold sold for $35 an ounce, we bought foil for approximately $18 per 1/10th ounce. Since the average class 5 foil weighs about 0.05 pennyweight, and the average class 3 foil weighs about 0.06 pennyweight, they contained about 450 and 540 worth of gold, respectively. Today. even though the market fluctuates wildly, if we consider gold at $700 an ounce, our foil is priced around $140 per 1/10th ounce. The mat and powdered golds are priced at 4% to 1 0% over that. The gold in the same class 5 and 3 foils then would cost about $3.50 and $4.20, respectively. Hardly enough to talk ourselves out of using this excellent medium!
The indications for direct gold may be debated and may be different in different parts of the country. In general:
Now, getting to specifics, there are a few fundamental requisites to be considered if we are to produce successful, lifetime restorations:
Complying with these requisites is facilitated by:
In the cavity preparation, briefly the requisites are:
As for any restoration, the operating field is important. There are two essential factors to consider:
The dry field is best attained with rubber dam. Different operators have different preferences about the details of obtaining such a field. Some find the frame type of holder to be adequate; others prefer the control of cheeks, tongue and lips afforded by the headband type of holder. Ireland (1962) has said that the most time consuming thing about the rubber dam is convincing dentists that they should use it.
To achieve a clear operating field for a gingival third lesion, a few operators make a surgical flap of the gingiva; however, most use a mechanical retractor, which, if well designed as is the Ferrier No 212, and if carefully applied, is less traumatic to the tissues. The matter of design, modification, and application of the retractor, while not complicated, does require training and guidance. There are several good sources of information in the literature if the assistance of an operator familiar with the technic is not available. If not used properly, the clamps or refractors can do much harm.
To achieve access to a proximal lesion, and to have a restricted preparation for it, a mechanical separator is an essential aid. It, too, must be well designed and correctly applied for maximum safety and optimal access. The Ferrier pattern has been the best design available for many years. For a time the separators did not measure up to specifications and required considerable modifying and refining. Now a new manufacturer, Atmore International (Portland, OR 97225, USA), is producing three of the six patterns. In the literature there is information about the application of these instruments (Stibbs, 1967).
TYPES OF GOLD
There are enough types or forms of gold to satisfy every taste and whim. Each will do a fine job it handled properly. Some are better than others. Basically there are three forms: foil, crystalline, and granular.
Gold foil, or fibrous gold, is one of the oldest, if not the oldest form we have. It is rolled and beaten by fascinating procedures. Gold leaf, as used in gilding or ornamentation, is about 1/250,000 in (0.1 µm) thick. Our dental foil (the usual No 4) is six times that thick, or 1/40,000 in (0.6 µm). It is available in several types:
Crystalline, sponge, or mat gold. In use for many years, mat is a microcrystalline form, produced by electrodeposition, the crystals being dendritic or fern-like in shape about 0. 1 mm long. It can be used plain or sandwiched in gold foil to make it easier to handle, in which form it is designated as mat foil.
Granular, or powdered, gold. The first ones appeared in this country about 1960, having gone through a number of evolutionary forms. These irregularly shaped, precondensed pellets or clumps of particles (Biotil, Filoro, Karat) were prepared by one of three basic methods: comminution, chemical precipitation, or atomization from the molten state. With some of them a volatile liquid was provided to act as a carrying medium to convey the pellet to the cavity. In general they are diff Icult to control.
As to the manipulation of the direct golds, there are a few principles to keep in mind:
So, you must have a means of cleansing the surface of the gold, and you need to apply controlled force.
Annealing. The cleansing or annealing to remove the volatile protective coating may be done pellet by pellet over an open flame of pure alcohol or en masse on an annealing plate having an electric, gas, or alcohol source of heat. The annealing temperature ranges from 650-700 ºC (not Fahrenheit) depending on the method and length of time of heating (Smith, 1973).
The easiest way is to have the chairside assistant anneal the gold as it is needed, over an open flame, heating just until the gold becomes a dull red. Care to not overheat it is important. It the protective coating is not driven off, the gold will not cohere, one piece to another. It is then considered noncohesive. The noncohesive type is useful to line and protect peripheral cavity walls in class 1 and class 5 preparations, and to rapidly build the proximal portion of a class 2 restoration.
Compacting force. The source of force can be by hand pressure alone (which becomes very tiring), or by hand mallet (which is strongly favored by many operators), or by a mechanical device that is activated by spring (Snow), pneumatic pressure (Hollenback), or electronically (Electromallet).
The direction, amount, and pattern of application of the compacting force are all highly important.
Direction: It is essential to direct the compacting force into the cavity, utilizing the property of flow of gold under pressure, in the direction of the force. The handle of the condenser should be at about 45º to the wall of the cavity. The direction should never be out of the preparation.
Amount: We recall from our early reading of G V Black and others that with a condenser having a face of 1 mm², the optimal force is 15 lb. But our condensers are not that large, A round-faced condenser of 1 mm diameter (which is still too large) has an area of 0.8 mm², so it would require a compacting force of 12 lb. The usual 0.5 mm diameter condenser has a face area of 0.2 mm², so the required force is but 3 lb. For Goldent, some recommend hand pressure only, using a larger-faced condenser (0.016 x 0.045 mm = area 0.465 mm²) and a force of 6-8 lb.
The condensers vary widely in shape and size. They can be straight, curved, or angled; they can be round, square or rectangular; they can be smooth or serrated; they can be flat-faced or convex-faced. It is well to begin with a basic minimal set and add to that as needs arise.
Hodson has pointed out that the plastic flow of gold occurs for only short distances under the face of the condenser (Hodson, 1961). Areas not covered by the face of the condenser remain porous (Hodson & Stibbs, 1962). Condenser penetration is less than the thickness of the increment (Hodson, 1964). The welding depth is not over 0.2-0.3 mm. Final density is influenced greatly by the direction and the magnitude of the compaction force, and by the size and shape of the face of the condenser (Hodson & Stibbs, 1962). The quality of compaction depends strictly on the operator's manipulative technic (Hodson, 1964).
Pattern: It is important to step the condenser in a controlled pattern. Methodical backslapping or overlapping, one half the diameter of the condenser face, produces the finest specimens (Hodson, 1964). Not only will this ensure uniform compaction and a dense mass, but also It will achieve optimal flow of metal, and sealing of cavity walls.
Porosity is inherent in any compacted gold restoration. In foil, the porosities are of the .closed' or cell variety. In the granular or powdered golds, porosities are of the 'open' type and therefore are more dangerous if not controlled (Hodson, 1964).
Each type of gold requires some slight variation in technic. If mat or powdered gold 'is compacted in the same manner as foil, it is very easy to have incomplete sealing of cavity walls, and incomplete compaction of the gold. Better results are achieved with condensers with a slightly larger face and finer serrations when working with mat. The powdered or granular pellets need to be opened up in the cavity before compaction begins, to minimize voids in the mass.
Some find that these golds crumble too readily in transporting them to the cavity, and that they are difficult to manage. Some operators obtain a dense hard restoration using only mat or powdered gold; others find that if these forms are used it is easer to obtain a better surface and polish if they apply a surface lamination of cohesive foil to the compacted mass of mat or powdered gold.
Finishing. In the finishing of any of the direct golds, the principles that have been used for many years for foil apply to the other forms as well.
BLACK. G V (1908) Operative Dentistry. Vol 2, p 225. Chicago: Medico-Dental Publishing Co.
HODSON, J T (1961) Microstructure of gold foil and mat gold. Dental Progress, 2, 55-58.
HODSON, J T (1964) Current studies on the physical properties of the various forms of pure gold. Journal of the American Academy of Gold Foil Operators, 7, 5-16.
HODSON, J T & STIBBS, G D (1962) Structural density of compacted gold foil and mat gold. Journal of Dental Research, 41, 339-344.
IRELAND, L (1962) The rubber dam: its advantages and application. Texas Dental Journal. so, 6-1 5.
SMITH, L E (1973) Reliability of electric annealers for gold foil. Journal of the American Academy of Gold Foil Operators, 16, 48-52.
STIBBS, G D (1967) Mechanical separators, Ferrier design. Journal of Prosthetic Dentistry, 17, 603-612.
For Further Reading
FERRIER. W 1 (1941) Use of gold toil in general practice. Journal of the American Dental Association, 28, 691-700.
HOLLENBACK, G M (1 961) The most important dimension. Journal of the Southern California Dental Association, 29.46-49.
PRIME, J M (1934) The rationale of gold foil. Dental Cosmos, 76,745-751.
SMITH, B B (1 973) Should you consider gold toil for your patients? Dental Student, 51, 46-47.
STIBBS, G D (1979) More and better foils: forward by fundaments rather than back to basics. Operative Dentistry, 4, 20-23.
AMBROSE, E R (1965) Prepared instrument trays for Ferrier class V gold foil restorations Journal of the Canadian Dental Association, 31, 566-574.
CLINE, H M (1949) Gold foil-the class V restoration. Journal of the Canadian Dental Association, 15, 252-257.
CRAIG, F M (1967) Teamwork in gold foil restorations. Dental Assistant, 36 (11),16-18.
DIEPENHEIM, J (1964) Class III gold foil restorations for lower anterior teeth. Journal of Prosthetic Dentistry, 14,1133-1139.
ELLSPERMAN, G A (1958) Fundamental procedures in gold foil operations. Journal of ProsthetioDentistry.8,1019-1025,
GOING, R E (1969) Pin-retained gold foil. Journal of the American Dental Association, 78,323-327.
JONES, E M (1 939) Treatment of initial caries in the anterior teeth with gold toil. Journal of the American Dental Association, 26, 532-541.
KINGS, E W & CUNNINGHAM, P J (1970) The class V gold foil restoration. Australian Dental Journal, 15,79-85.
KRAMER, W S (1960) Gold foil in pedodontics. Journal of the American Academy of Gold Foil Operators, 3. 58-72.
THOMAS, J J. STANLEY, H R & GILMORE, H W (1969) The effect of gold foil condensation on the human dental pulp. Journal of the American Dental Association, 78, 788-794.
WOODBURY, C E (1932) Gold foil. Journal of the American Dental Association, 19, 58-61.
JEFFERY, A W (1957) Invisible class III gold foil restorations. Journal of the American Dental Association, 54,1-6.
SMITH, B B (1950) Permanent and esthetic anterior restoration. Journal of the American Dental Association, 40, 326-332,
BLACK, G V (1907) The nature of blows and the relation of size of plugger points to force as used in filling teeth. Dental Review, 21, 499-519.
CARLSON, K E (1907) The problem of condensation and specific gravity of gold fillings. Dental Review, 21, 523-530.
HOLLENBACK, G M (1963) The why and the wherefore of laminated gold. Journal of the Alabama Dental Association, 47,17-19.
KOSER, J R & INGRAHAM, R (1956) Mat gold foil with a veneer cohesive gold foil surface for class V restorations. Journal of the American Dental Association, 52, 714-727,
LUND, M R & BAUM, L (1 963) Powdered gold as a restorative material. Journal of Prosthetic Dentistry, 13,1151-1159.
MAHAN, J & CHARBENEAU, G T (1965) A study of certain mechanical properties and the density of condensed specimens made from various forms of pure gold. Journal of the American Academy of Gold Foil Operators, 8, 6-12.
MILLER, C H (1966) Condensing gold foil. Journal of the American Academy of Gold Foil Operators, 9, 6-15.
MYERS, L E (1957) Filling a class V cavity with a combination mat and cohesive gold toil. Journal of Prosthetic Dentistry, 7, 254-258.
PETERSON, H W (1941) A study of the annealing temperature of gold foil. Northwestern University Bulletin, 41, 9-15,
PHILLIPS, R W (1973) Direct filling gold and its manipulation. In Skinner's Science of Dental Materials. Phillips, R W. 7th edition. Philadelphia: W B Saunders.
RICHTER, W A & MAHLER, D B (1973) Physical properties vs clinical perto"arice of pure gold restorations. Journal of Prosthetic Dentistry, 29, 434-438.
SMITH, 0 E (1972) Condenser selection for pure gold compaction. Journal of the American Acedemy of Gold Foil Operators, 15, 53-65.
STEARNS, C H (1901) Kinetics of the mallet. Dental Review, 15, 321-324.
STEBNER, C M (1959) Correlation of physical properties and clinical aspects of gold foil as a restorative material. Dental Clinics of North America. 2, 20-30.
WEDELSTAEDT, E K (1907) Methods and principles of packing gold. Dental Review, 21, 896-904.
WELK, D A (1966) Physical properties of 24 karat gold restorative materials-a progress report Journal of the American Academy of Gold Foil Operators, 9, 26-36.
WILLIAMS, R V (1971) As the manufacturer views gold foil. Journal of the American Academy Of Gold Foil Operators, 14, 66-70.
WOLCOTT, R B & VERNETTI, J P (1 971) Sintered gold alloy for direct restorations. Journal of Prosthetic Dentistry. 25, 662-667
ADELSON, R & CUNNINGHAM, P R (1973) Fourhanded application of the rubber dam by the expanded duty auxiliary and a dental assistant. Journal of the American Academy of Gold Foil Operators, 16,15-22.
BRASS, G A (1 965) Gingival retraction for class V restorations. Journal of Prosthetic Dentistry, 15, 1109-1114-
DILTS, W E & WITTWER. J W (1971) A surgical technique for tissue control with class V restorations. Journal of the American Academy of Gold Foil Operators, 14, 71-76.
LAW, D E (1973) Rubber dam application for children. Journal of the American Academy of Gold Foil Operators, 16, 37-42.
*Digitized and made Web available by Dr. Von Hanks & Dr. John R. Sechena
*Any additions or corrections send to Dr Von Hanks & Dr. John R. Sechena