A Philosophy for Restoring Virgin Caries
This paper demonstrates and discusses the clinical relevance for the use of direct gold, especially in restoring virgin caries in the modern restorative dental practice. In addition, this article is intented to highlight the advantages for oral health of placing restorative materials with the highest probability of long-term success. Also, this paper demonstrates the use of the latest formula of direct gold (E-Z Gold), developed by Dr Lloyd Baum of Loma Linda, CA, USA, and how this new product has made it practical to include direct gold restorations as an integral part of an active restorative practice.SUMMARY
INTRODUCTION
Direct gold techniques were developed at a time when bonding techniques, resin composites, glass ionomers or even high copper alloys were not available. In fact, for much of the “golden” years of direct gold restorative dentistry, the high-speed handpiece did not exist. However, the procedures developed for the placement of gold have proven to be as valid today as they were when the techniques were conceived. The reason these techniques have stood the test of time is that they are based in science, along with an understanding of the material and the environment into which the material is to be placed.
The reasons for a declining interest in these techniques have nothing to do with the fact that gold foil restorative procedures are sound, evidenced-based dentistry but with influences outside of the ethical dental practice. In addition, the development of newer materials offers a different paradigm for dentistry. The problem arises when a dentist uses a material to the exclusion of any other restorative materials, for example, “This is a metal-free office.”
There is ample evidence in the literature showing that, when used with proper technique and in the appropriate environment, composite restorations are serviceable for the least amount of time, alloy next, then gold restorations serving the longest, with direct gold having the longest serviceable life of all.1–6 In addition, there is anecdotal evidence by dentists who have practiced long enough to observe first-hand gold foil restorations such as the one featured in Figure 1. The patient had finally chewed a hole in the foil after 65 years of service; the repair, not the replacement of the foil, is shown in Figure 2. A dental student placed the original restoration 65 years ago. It begs the question how many foils has the reader performed in school that are still in service today? If the answer is none, the reader is most likely of the generation that went through dental school after this fine restorative technique was removed from the curriculum.
Citation: Operative Dentistry 33, 5; 10.2341/08-GF2
Citation: Operative Dentistry 33, 5; 10.2341/08-GF2
METHODS AND MATERIALS
A demonstration of restorative procedures, the material choices selected for restoring lesions in teeth with virgin caries and a small second generation restoration is presented.
The following materials were used in the cases presented.
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E-Z Gold, produced by Dr Lloyd Baum, Loma Linda, CA, USA (909–796–2152)6
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GC Fuji IX glass ionomer
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Shofu polishing points FG brownies, greenies and super greenies
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Suter Dental (800–368–8376) hand instruments
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Brasseler (800–841–4522) finishing burs, serrated steel saw blade and diamond finishing strips
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3M ESPE, SofLex finishing disc
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McShirley electro mallet
Obtaining an electro mallet will be difficult, since there are no known commercial manufacturers of this product today. However, numerous dentists who graduated from dental school in the 1960s and early 1970s have an electro mallet collecting dust in their closets. One option is to ask someone of that generation if he or she has a mallet that they would like to donate. You will be as surprised as the author just how many dentists are glad to give you their instrument.
In all cases, following local anesthetic and proper isolation with a rubber dam, the teeth were prepared utilizing preparations based on GV Black's principles of cavity design. The preparation of direct gold restorations requires attention to detail. Any discrepancies in the outline, form or cavosurface margins that are ragged will show up as obvious errors with a direct gold restoration. Sharp internal line angles and flat pulpal and axial walls allow for control of the line of force when compacting gold into the cavity prep.16 The preparations were completed utilizing a 169 taper straight fissure bur in a high-speed handpiece and appropriate hand instruments.
Following caries removal and rough cavity prep, lesions deeper than 1.5 mm into the dentin were based with GC Fuji IX glass ionomer. Glass ionomers are adhesive, they release fluoride and have thermal-expansion coefficients similar to tooth structure2 (p 408). In addition, GI forms an excellent foundation for the malleting process. Therefore, it is the opinion of this author that a GI is the base of choice under gold foil restorations, where a base is indicated.
After complete curing of the glass ionomer, if one is used, an ideal prep is prepared, with the outline form remaining as concretive as possible, keeping the foil protected from direct occlusal forces. For larger preps (preps where one or two pellets of gold cannot be wedged between two opposing walls), copal varnish is applied to the pulpal floor to help stabilize the first couple of E-Z gold pellets until enough initial gold can be placed to effectively wedge the gold into the cavity preparation. There are two principles involved in the compaction of direct cohesive gold. They are the welding process that occurs when a noble metal coheres to itself, combined with the wedging from careful compacting of the gold into the cavity prep1 (p 922).
E-Z Gold is placed using a combination of firm hand condensation with an Oregon #1 or similar condenser first, followed by mechanical condensation for each layer of gold. Mechanical condensation in these cases was preformed utilizing a McShirley electro mallet. Malleting, utilizing the traditional hand mallet process, also works well. Whatever malleting process is used, the condensation strokes should be overlapped and directed into the walls and corners of the preparation. This, in effect, pushes the gold into a micro fit with the cavity walls. Following complete condensation, the gold is finished by first raking the gold from the tooth using a sharp cleoid/discoid hand instrument and firm pressure. The initial shaping and carving is done by using FG finishing burs and a sandpaper disc mounted in a low speed handpiece utilizing air and/or water coolant at all times. The final finish was completed utilizing FG Shofu points with copious water coolant. The final polishing with mounted points has the effect of rounding out the occlusal surface, creating a smooth flowing final restoration that, in the opinion of the author, flows better with the overall contour of the tooth and is less reflective.
Figures 3–6 demonstrate a preparation for virgin Class I occlusal pits in #29 and placement of E-Z gold. In this case, the preparations were completed with a 169 straight taper bur, E-Z gold placed without a liner, then finished. This is the ideal restoration for this situation. First, cosmetics should not be an issue, especially if the patient understands the consequences to the tooth—that of placing a shorter lifespan restoration. The time to complete a restoration, similar to the one demonstrated, should be approximately 30 minutes; thus, the cost to the patient is not significantly more than other materials. Both restorations are protected from direct occlusion. In addition, this patient is in her twenties and has good periodontal support and a low caries rate. A foil was placed into the occlusal pit of tooth #28 at a subsequent appointment. However, all three restorations could have very easily been done at the same time, utilizing the fast build-up rate of E-Z gold.
Citation: Operative Dentistry 33, 5; 10.2341/08-GF2
Citation: Operative Dentistry 33, 5; 10.2341/08-GF2
Citation: Operative Dentistry 33, 5; 10.2341/08-GF2
Citation: Operative Dentistry 33, 5; 10.2341/08-GF2
Figures 7–10 demonstrate a foil restoration for tooth #13. In this case, due to virgin caries and the age of the patient, a gold foil restoration is the restoration of choice. No liner was placed, because caries removal did not require more that 1.0 mm of penetration into dentin. Due to the close marginal fit of gold foil, the patient should not experience sensitivity. A flat pulpal floor and sharp internal angles insure the control of the foil during placement and the subsequent malleting process.
Citation: Operative Dentistry 33, 5; 10.2341/08-GF2
Citation: Operative Dentistry 33, 5; 10.2341/08-GF2
Citation: Operative Dentistry 33, 5; 10.2341/08-GF2
Citation: Operative Dentistry 33, 5; 10.2341/08-GF2
Figures 11–15 show the basing-out of a foil. In this case, the virgin caries are deep in the mesial pit of #14. A base of GC Fuji IX was placed and allowed to self-cure before the final preparation was completed. The final finish was completed with Shofu polishing points on a high-speed handpiece with copious water coolant.
Citation: Operative Dentistry 33, 5; 10.2341/08-GF2
Citation: Operative Dentistry 33, 5; 10.2341/08-GF2
Citation: Operative Dentistry 33, 5; 10.2341/08-GF2
Citation: Operative Dentistry 33, 5; 10.2341/08-GF2
Citation: Operative Dentistry 33, 5; 10.2341/08-GF2
Figures 16–20 present a case where incipient caries places tooth #12 at risk. As can be seen in Figure 17, caries has already penetrated near the DEJ. The final preparation was completed with a 169 smooth taper bur, including, in this case, opening the mesial fissure. For the final restoration, E-Z gold was condensed and finished (Figures 19–20).
Citation: Operative Dentistry 33, 5; 10.2341/08-GF2
Citation: Operative Dentistry 33, 5; 10.2341/08-GF2
Citation: Operative Dentistry 33, 5; 10.2341/08-GF2
Citation: Operative Dentistry 33, 5; 10.2341/08-GF2
Citation: Operative Dentistry 33, 5; 10.2341/08-GF2
Figures 21–26 demonstrate the restoration of tooth #31. In this case, tooth #31 has initial caries well into the dentin. A glass ionomer base was placed (Figure 23) prior to placement of E-Z gold. The patient was in her middle twenties with a low carious rate and excellent oral hygiene. This is an example of caries formation under a resin sealant that had been done well. Figure 26 demonstrates the “flow” of a well-finished gold foil. The surface of the foil is in harmony with the surrounding tooth structure and has no flat surfaces to reflect light or show unusual wear over time.
Citation: Operative Dentistry 33, 5; 10.2341/08-GF2
Citation: Operative Dentistry 33, 5; 10.2341/08-GF2
Citation: Operative Dentistry 33, 5; 10.2341/08-GF2
Citation: Operative Dentistry 33, 5; 10.2341/08-GF2
Citation: Operative Dentistry 33, 5; 10.2341/08-GF2
Citation: Operative Dentistry 33, 5; 10.2341/08-GF2
Figures 27–32 demonstrate an incipient lesion at the point of carious breakthrough into dentin. Diagnosis was a distinct catch with a sharp explorer in the mesial pit of tooth #13. In this case, a simple direct E-Z gold restoration was completed. There is no liner or base, only E-Z gold. The patient, who is in his early twenties, will likely have this restoration well into his fifties or sixties before any additional treatment is indicated. Again, the finished surface is in harmony with the surrounding tooth structure.
Citation: Operative Dentistry 33, 5; 10.2341/08-GF2
Citation: Operative Dentistry 33, 5; 10.2341/08-GF2
Citation: Operative Dentistry 33, 5; 10.2341/08-GF2
Citation: Operative Dentistry 33, 5; 10.2341/08-GF2
Citation: Operative Dentistry 33, 5; 10.2341/08-GF2
Citation: Operative Dentistry 33, 5; 10.2341/08-GF2
In the future, the porcelain crown on the adjacent tooth (#14) will be more of a problem for this young patient than the small foil on tooth #13.
This patient arrived in the author's office with the crown on tooth #14 in place. The crown was well done. However, during routine examination, there was no caries found in the patient's mouth other than on tooth #13. Upon questioning, the patient related no pain or sensitivity in tooth #14 and there was no previous restoration. Asked why the tooth was crowned, the patient's reply was the “dentist said I needed it.”
Figures 33–38 demonstrate a second-generation restoration of a lower bicuspid. In this case, recurrent caries under the old alloy was deep into the dentin, requiring placement of a GI base (Figure 34). The contact area was opened using a wooden wedge. This allows good access for gold condensation into the buccal and lingual proximal surfaces. Gold condensation is started in starting points cut within the proximal box at the buccal-axial and lingo-axial line angles. The adjacent tooth is used as the matrix in this case (Figure 35).
Citation: Operative Dentistry 33, 5; 10.2341/08-GF2
Citation: Operative Dentistry 33, 5; 10.2341/08-GF2
Citation: Operative Dentistry 33, 5; 10.2341/08-GF2
The proximal box is filled first. When the gold reaches the level of the pulpal floor, the gold is extended over into the Class I part of the prep and the complete cavity is filled with gold (Figure 36).
Citation: Operative Dentistry 33, 5; 10.2341/08-GF2
With the wooden wedge still in place, a serrated steel saw blade (Brasseler #9816) is used to cut through the contact. Then, diamond strips (30 and 15 micron, Brasseler) are used to polish and contour the interproximal gold. The wooden wedge is removed prior to final finishing of the proximal contact in order to set the contact with the proper pressure. By not using a matrix band, there is always more than enough gold to create an excellent contact with the adjacent tooth (Figure 37). Final finishing and polishing of the restoration is completed using a SofLex finishing disc (3M ESPE) and Shofu FG mounted polishing points and brownies-super greenies with copious water coolant (Figure 38).
Citation: Operative Dentistry 33, 5; 10.2341/08-GF2
Citation: Operative Dentistry 33, 5; 10.2341/08-GF2
DISCUSSION
Today, with the mantra of cosmetic dentistry driving the selection of restorative materials, the use of gold for the restoration of teeth in this country is becoming a dying art. This is due, in part, to gold restorative techniques being no longer required in the licensure examination process. This has led dental schools, by-and-large, to either remove the discipline from curriculums, substantially curtailing student exposure or offer it as an elective, left to be chosen by those who “do not know what they do not know” (Guest Editorial, Operative Dentistry, 33–3).
If the purpose of dental education is to teach one to pass a dental licensure examination, all dental schools in this country are doing a good job. If, on the other hand, the purpose of dental education is to inspire to the higher goal of being a doctor of oral health, then cosmetic dentistry should be a vital part, but not the driving force for restoring teeth. The title of doctor implies the ability to teach and to heal. Therefore, the ability to teach patients how to maintain good oral health for a lifetime and the ability to restore teeth for a lifetime of function then becomes the driving force within the discipline of operative dentistry. Using this precept as a core value of patient care, the longevity of restorative materials then becomes a major factor in considering what materials to use when restoring a carious tooth.
Take the examples of the incipient lesions shown in Figures 16 and 27. There are several choices for treatment in these two cases. One option is to do nothing. The problem with waiting to intervene is that this would allow decay to invade the dentin of the tooth to a greater depth, creating the potential for a much larger initial restoration. An inexperienced dentist or an unsupervised auxiliary might want to seal the teeth with either a resin composite or possibly a glass ionomer. The problem with this approach is that there is caries already present, and sealing it under the resin or GI would allow for further breakdown of the tooth, most likely at an accelerated rate. This approach also would lead to a much larger initial restoration in a shortened period of time.
The teeth could be immediately restored using a fourth-or fifth-generation resin composite, most likely the treatment of the masses today. The problem with this solution is that, within five-to-eight years, the composite restoration will fail due to microleakage around the margin, then a larger restoration with more tooth loss would be needed in a relatively short time from initial restoration of the teeth. Due to the young age of the patients, the teeth would be committed to a cycle of continuous restorations at an accelerated rate, relatively early in the lives of the patients.
The teeth could be restored with a conservative alloy. This would be the author's second choice. A first generation restoration with alloy would remain serviceable most likely for 20–30 years. The problem again would be what would need to be done when the restorations failed, with recurrent caries and tooth fracture caused by the expansion rate of the alloy over time.
The problem with any of these approaches is they do not take into consideration the longevity of the first generation restoration and the consequences of a continuous cycle of restorations over a longer period of time for a younger patient. The choice of restorative material for the first restoration in a tooth, especially in a patient who is in his or her teens or twenties, will be a major determining factor if that tooth will keep an internal restoration for the life expectancy of the patient, will end up with full coverage or possibly be replaced with a prosthetic device. Serviceability of a restoration without damage to the tooth is achievable if the initial restorative material has a coefficient of expansion that is very close to tooth structure, has marginal integrity where leakage is not likely to occur, is corrosion proof, has hardness similar to tooth structure and is very biologically compatible. When annealed gold is worked hardened, the tensile strength is increased to 32,000 psi, the yield strength to 30,000 psi and the Brinell hardness to 58.8
However, if the initial restorative material is selected based on color, cost, convince or a caviler attitude of attending to the “expensive stuff” first, the consequences to the tooth and the patient of a failed restoration in a relatively short period is grave. In the cases of the first time restorations shown, the treatment of choice is to place gold foil. Gold foil, properly placed, has the potential to block further restorative procedures for an inordinately long time, thus virtually insuring the patient of having the teeth intact at the end of his or her lifetime.
If maintaining good oral health with healthy teeth for a lifetime is a core principle within the reader's practice, then the ability to place all restorative materials with proper technique, within appropriate environments and in consultation with the patient would naturally follow. In this context, consultation with the patient means giving choices based on a clear understanding of the possible outcomes for the various choices. This type of patient management brings into focus the dentist's ability to inform and perform. It has been the experience of the author over 30 years of practice that, when a patient understands the physical properties and outcome expectations of all restorative options, cosmetics tend to be lower on the list of concerns.
Therefore, following this line of thinking, dental education should include comprehensive training in the art and science of placing all available restorative materials, including gold foil, with an emphasis on selecting materials that optimally meet the need and the environment into which it is to be placed. A comprehensive dental education program based on a “needs based” approach would include decision-making based in science, ethics and outcomes assessments. This would help the new dentist avoid the pitfalls of a “wants”-based practice. In addition, by learning the techniques required to place direct gold restorations, the student will benefit from an enhancement of abilities in all disciplines.
CONCLUSIONS
It is hoped that this presentation will cause readers to reevaluate how they decide what material to use for restoring teeth, especially virgin caries on the younger patient. Decisions based primarily on the color of a restorative material could place patients in a compromised position concerning their oral health in the future. However, if the patient is given restorative options that have high probabilities of success for 30 years and beyond and is also given the information needed to make informed decisions about their own oral health, the doctor might be surprised how many times the patient will choose health over vanity.
In the opinion of this author, this country is at a crossroads, with the potential to have a new generation of people who may not have all their teeth throughout their lifetime. This potential crisis has the consequence of relating to failed restorations and a seemingly broad shift in the paradigm from excellence to production. It is time to think about looking back to go forward to improve oral health in this country. A few dentists alone cannot stop the tide of mediocrity. It will take the concentrated efforts of dental educators, the American Dental Association, the private practicing community and government, all working together to not only teach the next generation of dentists to be competent but to inspire these young professionals to excellence based in science and ethical outcomes of treatment.
Sixty-five year old foil with wear and occlusal perforation.
Repair of the restoration in Figure 1.
Occlusal caries in the mesial and distal fossae of tooth #29.
Caries removal in mesial pit.
Direct gold restoration in tooth #29.
Direct gold restoration in tooth #29.
Occlusal caries in tooth #13.
Cavity preparation in tooth #13.
Direct gold restoration in tooth #13.
Completed restoration in tooth #13.
Occlusal caries in tooth #14.
Caries removal in tooth #14.
Glass ionomer cement placed as base in tooth #14.
Direct gold restoration in tooth #14.
Direct gold restoration in tooth #14.
Occlusal caries in tooth #12.
Occlusal caries removed, mesial involvement revealed.
Completed preparation in tooth #12.
Completed restoration.
Direct gold restoration in tooth #12.
Isolation of tooth #31.
Caries removal in tooth #31.
Glass ionomer base placed in tooth #31.
Condensation of gold.
Completed restoration.
Direct gold restoration in tooth #31.
Insipient carious lesion, occlusal tooth #13.
Conservative caries removal.
Completed condensation of direct gold.
Completed restoration.
Direct gold restoration in tooth #13.
Direct gold restoration in tooth #13.
Defective alloy with mesial caries in tooth #29.
Caries removed and glass ionomer base in place.
Condensation of gold into mesial box.
Completed condensation of direct gold.
Completed restoration.
Direct gold restoration in tooth #29.
Contributor Notes
Dan B Henry, DDS, FACD, FICD, Pensacola, FL, USA