We, in dentistry, still have choices to make. Probably, at no time has the profession been offered so many choices in patient treatment, especially as it relates to restorative dentistry. In any case, the quality of esthetic treatment is a major consideration in restorative treatment today.
Hopefully, white is not the only consideration. Until recently, gold was considered to be the esthetic restorative for posterior teeth, as it does not discolor the teeth and the color gold was considered less objectionable than other materials. As we have become more aware of esthetics in dentistry, we also have developed new techniques, even with gold, which do not destroy the beauty of a smile. There is renewed emphasis on intracoronal gold restorations, which can be placed by showing no metal or, in some cases, very little metal, by the proper design of cavity preparations.
We also show proper consideration of a badly destroyed tooth by placing tooth-colored crowns, rather than display so much metal. As new materials and concepts evolve, dentists have learned to perform very esthetic dentistry by using gold as a restorative. As mentioned, I would hope that other considerations, such as longevity of the restoration, would be considered, along with proper contour, proper contacts and maintenance of the occlusion. No material satisfies these requirements as well as gold.
Of all the attributes gold has to offer, the most valued is the longevity of gold restorations. However, I have seen countless patients whose teeth were restored with gold 40 or 50 years ago, many without further treatment than the original restorations.
When my oldest daughter was born, I took the occasion to restore my wife's teeth with gold, which had amalgam on all posterior surfaces. She was in the no-fluoride generation. Every tooth, except for a lower second molar that fractured a cusp, has remained as restored as it was originally done 60 years ago. Not a single tooth is submarginal, leaking in contour or has open margins or lacking proper contacts.
It is this type of experience that has caused me to list the following reasons to support the use of gold castings. The gold inlay or onlay is obviously not tooth-colored. However, the filling is usually not objectionable, because it is in the posterior part of the mouth, where it is not normally visible. It would seldom, if ever, be recommended for anterior teeth.
The teeth should be prepared in such a manner that the patient would not display gold as they speak or smile. Gold casting is more expensive than amalgam or composite restorations. It requires two appointments: one to prepare the cavity and a second to deliver. In addition, there is the expense of the laboratory fabrication between preparation and delivery.
The dentist must design a cavity preparation with no undercuts, allowing the casting to withdraw from the cavity, while fulfilling all the other requirements of a good preparation.
There are many different preparation designs, depending on the extent and position of the lesion on the tooth. Some things have made the process easier over the years, including significant improvements in impression materials, which enable extremely accurate reproduction of the preparation for the laboratory. The actual gold casting, which is an alloy that gives the most advantageous properties to the metal, is fabricated in the dental laboratory, providing the control necessary to obtain a very accurate fit.
The cost of the gold itself is a minor expense and, although more effort and time are necessary, the cost, when compared to the longevity of the restoration, suggests that it is not really more expensive for the patient in the long run. As with any dental procedure, the dentist must be trained to accomplish successful gold restorations.
Knowledge and understanding are required, so that the final restoration is accurate and fulfills all the requirements of providing long-term function and service. It is a fairly demanding procedure for the dentist and is definitely not for someone who is not willing to make the necessary effort. The gold casting will never break or fracture when properly prepared. Silver amalgam, due to its brittle nature, has a greater tendency to fail under load. Fracture does not seem to be a significant problem with resin composites.
The gold casting maintains marginal integrity even after many years of function. The composite filling, though tooth-colored, gradually erodes away, which may leave the enamel margins unsupported and prone to chipping and wear.
The favorable coefficient of expansion of the gold alloy, as compared to that of the tooth, is important. The tooth and restorative material shrink when exposed to cold and expand with exposure to heat. Since the temperature in the mouth varies from cold ice cream to hot coffee, it is important that the filling material expands and contracts to a similar extent as the tooth structure.
The gold casting can be placed so accurately in the tooth that the enamel at the margin of the cavity is supported, so that, as the patient functions, the enamel is protected from breakage.
It is as if the gold braces the enamel rods to prevent them from breaking down. Returning a tooth to its normal, healthy form is elementary for any restoration. This produces a restoration that allows proper function with opposing teeth and allows food to pass over the dentition in a normal chewing and grinding motion. The gold casting is made in the laboratory from an accurate replica of the preparation and adjacent and opposing teeth.
Since it is fabricated outside the mouth in a far more open environment, it is possible to create a final restoration that is as close as possible to ideal. There are obviously advantages to having a highly polished restoration. It is much easier to accomplish this in the laboratory, where we have much better access and visibility and are not dealing with oral tissues and fluids.
The polish surface is less likely to accumulate plaque and presents a more pleasing feel to the tongue. While it is true that gold is not likely to flow or change shape in the mouth, the improvements in high copper amalgams tend to make it less of a comparative factor than it was 30 years ago.
Saliva and other oral fluids will not penetrate the surface of a gold casting. On the other hand, resin composites are penetrated by oral fluids and occasionally absorb enough so that there is a putrid smell when they are removed.
Warren Johnson, DDS, who has mentored several of the Tucker study clubs, demonstrated the excellent margination that can be achieved with cast gold. Using an extracted tooth, he followed the Tucker technique to seat a gold inlay with zinc phosphate cement and then finish it Figure 7. He then took scanning electron microscope SEM images and measured the gap at the gold-tooth interface, which was Nm Figure 8 and Figure 9. The following case demonstrates how cast gold restorations can be esthetic when conservatively placed.
A year-old, female patient presented to the practice, frustrated because she did not like the appearance of her teeth. In addition, she was getting food caught between her teeth and was experiencing chipping Figure 10 through Figure She had undergone significant restorative dentistry in previous years and was frustrated by the constant need to replace these restorations because of decay, leakage, or fracture.
Having done some research prior to presenting, she was interested in finding a clinician who was proficient in restoring with gold because she had heard about its longevity. The patient indicated that she had reached a point in her personal dental experience where she was willing to put in the time and allocate the necessary finances to have restorations placed that were as permanent as possible.
Intraoral and radiographic examinations were performed, which revealed the presence of decay on the mesial-lingual aspects of teeth Nos. The patient was also experiencing food impaction between teeth Nos. Finally, there was a small chip on the lingual aspect of the porcelain crown on tooth No.
Different treatment options were discussed, including the advantages of gold castings and how they can be designed to avoid a significant display of gold. Although gold castings are not tooth-colored, cost more than other restorative materials, and require significant skill and technique from the operator, their advantages are considerable.
Gold castings will not break, fracture, exhibit marginal wear or discoloration, or abrade the opposing dentition. The patient was referred for orthodontic treatment in order to address the crowding of both the maxillary and mandibular teeth, increase overjet, and intrude teeth Nos. Prior to orthodontic treatment, the decay was removed, a temporary crown was placed on tooth No. The patient was questioned about her diet and then educated about related factors that could be contributing to the condition of her teeth.
In addition, she was prescribed a low abrasion tooth gel CTx4 Gel , CariFree to routinely use before bedtime and told to drink tap water after every meal or snack to help rinse the acids off of her teeth and raise the pH of her mouth. After 10 months of orthodontic treatment, the patient returned to the office for further consultation regarding restorative treatment.
A treatment plan was devised that would brighten and enhance her smile while also restoring her posterior teeth as permanently as possible. They looked noticeably whiter, and the patient was pleased with the result. Next, the focus shifted to treating her maxillary posterior teeth. Using the Tucker technique for cast gold restorations, taking special care to keep the occlusal outline forms inside of the cusps, the teeth were prepared for gold inlays with the exception of teeth Nos.
The Tucker technique for the placement of a quality cast gold restoration involves a specific series of steps that includes, "diagnosis, tooth preparation, impressions, models, wax-up, investing, casting, cementation, and finishing.
A flaw in any one of these steps or lack of attention to the finest detail would result in failure or an unsatisfactory result. The single step which contributes to a large number of failures, and that which requires a special effort from the operating dentist is the cavity preparation. The patient's upper left quadrant was prepared, and an impression was taken.
At the next appointment, after seating the restorations in the upper left quadrant, the upper right quadrant was prepared, and an impression was taken.
As demonstrated by the outlined preoperative photograph Figure 13 , some of the old composite restorations were fairly extensive; therefore, the goal was to prepare the previously restored teeth as conservatively as possible-including the isthmus width and gingival and axial depth-while satisfying all of the preparation requirements eg, draw, flare, resistance, retention, depth and creating a flowing outline for every restoration.
The resulting outline forms were kept inside of the cusps, and the preparations were not extended out to the visible areas of the teeth. Careful impressions and laboratory work resulted in the creation of some fine-fitting gold castings. After the seating of the inlays, all of the accessible margins were finished using a series of sandpaper discs ie, medium garnet, fine sand, fine cuttle.
The discs were slowly rolled across the margins from gold to tooth, reducing the level of the gold until it was on the same plane as the tooth structure and closing the marginal gap by burnishing and pulling the gold.
After the finishing was completed, final polishing was performed using a series of polishing powders to achieve a beautiful luster Figure When the finished upper-arch photograph is compared with the preoperative photograph, it can be visualized that the final outlines of the gold castings are very similar to those of the old composite restorations, which demonstrates that as much tooth structure as possible was conserved.
Finally, with attention to detail and a conservative composite bonding protocol, a predictable long-term esthetic result 12 was achieved for the patient's anterior teeth. Adding to these teeth ie, Nos. The patient expressed her satisfaction with the final result, which was a beautiful, pleasing smile with no gold on display.
In this case, a combination of conservative treatment protocols was employed to minimize the need for further tooth reduction and achieve the final result. The protocols included orthodontics to get the teeth in their proper positions, tray bleaching to brighten the remaining tooth structure before restorative procedures, composite bonding of the anterior teeth to enhance their esthetics, and finally, conservative cast gold restorations to restore the maxillary posterior teeth.
To satisfy the desires of this patient, the treatment plan was designed with both longevity and esthetics in mind, but which is more important? The answer is in the eye of the beholder. For some patients, longevity will trump esthetics or vice versa, but for other patients, they are equally important.
The only way to know for sure is to go beyond merely providing an exam and have a conversation with patients. Healthcare providers are obligated to perform thorough examinations and then discuss their findings with patients.
It is also their responsibility to educate patients about their needs and discuss possible treatment options for any significant issues.
By setting aside time to show patients intraoral photographs of their mouths, discussing treatment alternatives with before-and-after photographs, and giving them enough information that they can make educated decisions, clinicians enable patients to give informed consent on the treatment of their choosing. Tucker emphasized the discipline and attention to detail that it takes to prepare, seat, and finish a fine gold casting.
Through study clubs, his teachings, techniques, and cookbook approach to gold castings have been passed on to thousands of dentists who have applied them properly to achieve predictable, excellent results. Oftentimes, these skills, this discipline, and the conservative nature of gold castings carry over into other areas, improving a clinician's dentistry overall. In this regard, it could be argued that the training and skill of the operator has as much to do with the clinical longevity as the choice of restorative material.
The moral to this story, as John Kois, DMD, would say, is that "you have to show the patient the menu. Cast gold restorations deserve to be on the restorative material menu. Regarding the longevity of gold castings, Tucker notes that they "are usually relatively permanent. We often see gold restorations that have been in service for 40 or 50 years. The permanence of gold fillings is the most obvious reason for their use.
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