IS OLD STILL GOLD?

IS OLD STILL GOLD??? – Gold foil restorations

The quest to search the ideal restorative material has been a challenge for the researchers and academicians in the fraternity of restorative dentistry. With the rapid advancement in the bio material science and bio technology, most of the material properties have drastically improved in the recent years. Among the available restorative materials, direct filling gold is the oldest filling material that is still used in restorative dentistry. The concept of using metal as restorative material has arisen from the identification of mechanical demands of the oral apparatus. The vision to utilize the noble metals for the replacement of lost tooth structure stemmed from perfect harmony of its biological and mechanical properties excluding esthetics. While most of metals can be welded and alloyed at a temperature above the room temperature, the pure gold can be cold welded and made to adhere to each other at room temperature. This property coupled with strain hardening by which the strength and hardness of the material is increased as it is cold worked or welded makes direct filling gold unique. Since it is very ductile and malleable, the gold can be worked well against the walls of the cavity, creating excellent marginal adaptation of the restoration. However placing a gold foil restoration requires highly demanding and skilled operator. A well done direct gold restoration can last ones lifetime (1), in the properly selected cases.

Introduction:

Current status of gold foil: In spite of many favorable properties, the placement of gold foil restorations is at decline, both in the university based practice and in private practice globally. In India, it is almost none. In an excellent review by Gerald.D.Stibbs(1987)(2), he critically evaluated the reasons for this decline. The reasons stated by Gerald.D.Stibbs in universities/dental schools are: 1. Lack of emphasis of direct gold restoration in dental curriculum. 2. Lack of trained staff in direct gold restorations. 3. Change in overall attitude to settle for less than the best restoration. He further states that the same decline in private practice is because of the change in the current philosophy of practice. The olden days practice was based on more value based treatment with the concept of “need based practice” as the pivotal point. The need of the patient was given maximum importance and the same was delivered by the dentist and was equally accepted by the patients. But the present day private practitioner is more with a philosophy of “want based practice”. This change in demand by the patients, propelled by legal and insurance coverage factor has led the dental operators to deliver the treatment of what the patient wants than what is actually needed.

In the minimally invasive era…

Tooth colored material with both optical and physical properties similar to that of tooth structure is the current emphasis of research. The metallic restorations including direct filling gold definitely can not satisfy the esthetic demands. However there is no cost effective esthetic material that can last functionally and durably as direct filling gold for small lesions. Hence, when indicated for selected posterior teeth where the esthetic demand has been created iotrogenically, direct filling gold will be the prudent choice of material.

In the esthetic era…

Is there sufficient evidence to support and use direct filling gold as restorative material? The concept of evidence based dentistry has surfaced the past decade and most of the evidence based studies regarding longevity and holistic analysis of restorative material is from 1990. the material science researches is at snail pace for the direct filling gold. Even then, it has recent improvement with EZ gold and various types of precipitated gold. Most of the research regarding gold foil was done from 1900 till 1985. Where the direct filling gold restoration has stood the test of time , as G.V.Black pointed out in 1908,there is no restorative material as good as gold foil to take the full advantage of the modulus of elasticity of the dentine. The research in the arena of gold foil and other metallic restoration are not very aggressive because most of present researches are supported and funded by the manufacturers.(3) university based researches, other non profit funding agencies are very minimal and in the current scenario. Research based by manufacturers will definitely eclipse around the demand and the want of the patients. In the light of evidence based dentistry, the direct filling gold does not have any evidence to support; even then it has proclaimed itself to be one of the most durable materials from 1900 -1980!!

In the era of repair and replacement…

With the current evidence and in depth knowledge and understanding of restoration cycle, the concept of repair has gained acceptance than replacement. The ignored fact is that it may not be required to replace or repair a restoration if its durable with good marginal integrity.(4). Gold foil stands best with its marginal integrity and with current advancement, of mat and precipitated gold, it is possible to carry out an exact replica of both cast gold and direct filling gold restoration with the gold foil.

In this evidence based era…

One of the foremost thought of the restorative dentistry is that “now are we justified by doing gold foil restoration in this era, where conservation of tooth structure is the mantra? “Conservation of tooth structure in the context of minimally invasive technique is a very much misunderstood concept. Any modality to conserve the tooth structure should be viewed in association with the longevity of the restoration. The hidden factor often overlooked in the longevity of the restoration is the “restoration cycle”. Restoration cycle means that how regularly it is required to replace the restoration during ones lifetime. It has been proved that every time a restoration is replaced ,there is always an inadvertent removal of tooth structure. Also, this is more to do for the tooth colored restoration. Hence, if a restoration which is more durable because of the material per se, is likely to be the most conservative treatment plan than a restoration which can be restored with minimal cavity preparation but will last only for few years. In this ranking, direct filling gold is the most durable material that is available in the restorative material sciences. In fact, the cavity preparation is very minimal and can last long for small pits and fissures and proximal lesions.

With the current evidence and in depth knowledge and understanding of restoration cycle, the concept of repair has gained acceptance than replacement. The ignored fact is that it may not be required to replace or repair a restoration if its durable with good marginal integrity.(4). Gold foil stands best with its marginal integrity and with current advancement, of mat and precipitated gold, it is possible to carry out an exact replica of both cast gold and direct filling gold restoration with the gold foil.

Conclusion:

Even though gold foil restoration and the materials are very much favorable, the evidence to recommended its use is not available since the research has been stand still for the past 2 decades on one of the best restorative material. Also, unlike other restorative techniques, the gold foil restoration which has not been done to the highest degree of perfection, the same very best material can be the very worst restoration! The option to utilize gold foil as the best restoration or worst restoration totally rests on the shoulder of the operator!! Unless a conservative dentist takes a conscious attempt to tame and master this wonderful material and technique for many indicated lesions, the patient will be deprived of the very best treatment because of the fallacy of the conservative dentist.