The Use of CAPTEK for Full Coverage Restorative Dentistry
By Edward Feinberg, DMD©
Criteria for Successful Restorations
The success of any type of restoration depends on several factors:
1. A definitive diagnosis that correctly identifies the patient's problem.
2. A sound treatment protocol that solves the problem, satisfies the patient's needs and desires, and offers a contingency plan in the event something goes wrong.
3. A solid technique that is predictable, repeatable and reliable.
4. Structurally sound restorations that promote patient comfort, periodontal health and neuromuscular harmony.
5. Longevity with preservation of the abutment teeth for replacement restorations. Dentistry is not lifetime. The body changes and materials wear, and at a certain point new restorations may be required to compensate for these changes.
There is no doubt that success according to these criteria can be obtained with any type of restorative treatment depending upon the individual that is selected. A young, healthy individual can usually withstand any treatment for a period of time. However, as the body ages or becomes subject to disease it is less able to tolerate insults. A case in point is the homeless alcoholic living in filth that lives to be 90 years old. One would be hard-pressed to recommend this lifestyle because the percentage of 90 year olds who live this way is very low.
The true test of any treatment is the percentage of success across the board--where older patients predisposed to dental and systemic disease are included as well as young, healthy ones. X-Ray documentation and follow-up every two years is an important measure of change how well a restorative treatment has succeeded.
Types of Restorations
There are several types of restorations that have enjoyed documented success according to these criteria.
A. Gold/Acrylic Veneers
The first full coverage restoration in dentistry--gold with or without acrylic veneers--enjoyed a high degree of longevity, biocompatibility and a low incidence of breakage. Gold is still perhaps the finest restorative material in terms of fit, accuracy, and longevity. However, it is very unaesthetic in today's youth-oriented culture, and no one wants gold in his or her smile. Although easily repairable, acrylic is lifeless in appearance and prone to discoloration and wear.
Figs. 1-4: This case--anterior porcelain-fused-to-metal and posterior acrylic veneers--was completed in 1974. The dentistry has lasted in health for almost 30 years. Note how the dentistry mirrors the bone in the finished X-Rays. This architecture is ideal for maintaining health, and there has been very little change in the X-Rays since the case was completed.
B. Porcelain Fused to Metal (PFM)
Porcelain fused to metal restorations were much more esthetic restorations than acrylic veneers. Although it was not nearly as prone to discoloration as acrylic veneers, it was much more prone to breakage, and more difficult to repair intra-orally. The fit of porcelain fused to metal was different than that of gold restorations. The metal for porcelain is an alloy of metals, because firing porcelain requires temperatures above the melting point of pure gold. This alloy is much more rigid and less forgiving than gold. Acrylic veneers could spring over a full shoulder without harm to the acrylic veneer. Often the only preparation of the root surface that was necessary was curettage with hand or low speed instrument. Porcelain-fused to metal restorations can not snap over a full shoulder without flaking of the marginal porcelain. These restorations musts fit passively . Rounding of the edge where the shoulder meets the edge and removal of undercuts in the preparation is a must. The PFM precious and semi-precious alloys require at least .5mm thickness to support opaque and porcelain (dentin plus enamel), which does not communicate adequate translucency for maximum esthetics. Although nonprecious alloys can be made thinner, they do not bond chemically to porcelain, cannot be accurately cast so that they fit the dies without reaming the inside, and are difficult to solder.
C. Porcelain Jackets
Porcelain jackets were the first truly esthetic restoration. Because they contain no metal at all, the color and translucency closely approximate the beauty of ideal natural teeth. Color modifiers for the cementing medium are required to achieve the desired shade. The original porcelain jackets were much stronger than today's porcelain jackets. They contained an aluminous core that required a special high-fusing muffle. This type of porcelain is no longer manufactured, and today's porcelain jackets are created out of porcelain that is really designed for porcelain-fused-to-metal restorations. The biggest disadvantage, however, is that the porcelain jacket is a butt-joint restoration. In other words, the porcelain jacket cannot have an apron to adequately seal the prepared tooth structure. Because the porcelain jacket is usually confined to the anterior section of the mouth (the most accessible for cleansing), there is good clinical success.
Fig. 5-7: This case was done with porcelain jackets in 1977. Note how the teeth were prepared with full shoulders and how the gingiva was reshaped for restorations that are ideal shape and form. This type of porcelain jacket is no longer on the market.
D. Renaissance
In the early 1980's a new material was developed that combined the best of the porcelain jacket and the porcelain-fused-to-metal restora
tion. Invented by from Israel, the new material--called Renaissance--conferred the advantage of lifelike translucency characteristic of porcelain jackets without the necessity of color modifiers for the cementing medium. The Renaissance Jacket was an umbrella of gold and platinum foil that was burnished and swaged on the die and heated to solder the pleats and solidify the copings. In the days of acrylic veneers, there were no dipping waxes, and conventional wax pulled away from the die leaving gaps. To compensate, gold or platinum foil was burnished and swaged on the die. The result was extremely accurate adaptation to the die and ideal fit. Renaissance was a direct technique that did not require investing and casting, so it was perhaps the most accurately fitting restoration ever devised. Thousands of Renaissance jackets created during a 20 year period exhibited a remarkable low incidence of breakage--far lower than PFM restorations. [The Renaissance material was recently removed from the marketplace and replaced with CAPTEK , a material of similar composition].
Figs. 8-10: This case was done in 1984 with Renaissance jackets. Note how the jackets restored ideal, shape and form to an ideal plane of occlusion.
Fig. 11-17: These lower anterior teeth were created with Renaissance jackets in 1999. Renaissance jackets had the advantages of finished thickness of .7-2mm; excellent strength; good color clarity; accurate fit; and fast, easy fabrication. These qualities are ideal for lower anterior restorations. Note how the models were first waxed on the model to determine that endodontics and gingival/osseous reshaping were necessary to restore the teeth to an ideal shape, form and alignment. Note how the jackets in the X-Rays mirror the underlying bone. Renaissance is no longer on the market.
Prevention Against Recurrent Decay
One of the biggest advantages of Renaissance was the ability to adequately seal the tooth structure. No porcelain jacket or ceramic restoration can seal the tooth structure properly because they are butt-joint restorations. On a microscopic level there is always an opening between the restoration and the prepared tooth structure
--an opening that is certainly large enough for a bacteria. An individual who is prone to decay is likely to end up with recurrent decay around butt-joint restorations. There is today too much confidence placed in bonding materials to adequately seal this interface. The problem of recurrent decay is greatly minimized with proper tooth preparation and restorative techniques. The basic fundamentals of tooth preparation are full shoulder preparations; a three dimensional approach that includes the tooth, the ginigva and the bone; and accurate impressions and models.
The full shoulder preparation has superior advantages that make it the preparation of choice for all full coverage restorations regardless of the restorative material selected. (The only exception is the fractured tooth that would require excessive osseous surgery to restore with a full shoulder) These advantages include:
(a) A Definite Finishing Line. With a full shoulder preparation, the margins are easily identified.
(b) Repeatable Fit. Castings with aprons created for full shoulder preparations with accurate impressions and models fit, rather than "go on" . It is easy to discern if they are seated properly and the restorations are so retentive that they are typically worn for a trial period with Vaseline ointment or Trial (a thin rubber-like material from Opotow).
(c) Decreased Sensitivity. A good full shoulder preparation is not over-tapered in the area of the axial walls, so irritation of the pulpal horns is avoided. The shoulder allows accurate temporaries that eliminate sensitivity and gingival irritation between visits.
(d) Ease of Parallelism. The full shoulder preparations can be made parallel for maximum retention and allow passive fit of splinted restorations.
(e) Distribution of Stress. The shoulder absorbs some of the forces that previously were concentrated on the occlusal surface. These forces are now closer to the supporting structures and equally distributed around the tooth. The simple act of placing a shoulder on a weak tooth causes it to tighten up. The shoulder stabilizes the foundation, and for this reason virtually all buildings are built on the shoulder concept--not the chamfer concept.
Prepar
ation of the apron is an important key to success of the restoration. Often the shoulder preparation includes a bevel to which the restoration is extended. The approach is no better than the butt-joint design, however. The finishing line--regardless of the operator' skill--is never a straight line. Under a microscope it appears as a jagged edge. The restoration finished to the end of the bevel is unlikely to cover all of the microscopic jagged edges, especially with all of the error introduced by the indirect fabrication of models and castings. Decay causing bacteria can easily find a home in a microscopic jagged edge of cut tooth structure--especially in an individual prone to decay. To a bacteria the uncovered jagged edges are like the Grand Canyon.
To prevent this scenario, the apron should be prepared with a pseudo-bevel. The sharp interface where the shoulder meets the apron is rounded with a large flame shaped diamond (that cannot go very far below the gingival). If there is a white cap of enamel at this interface, it should be removed, since it could flake off with the try-in of castings. Any undercuts should also be removed with this high speed diamond. The rest of the root surface is prepared with curettage and a large diamond in a low speed handpiece to remove any tartar and loose enamel rods. Curettage is facilitated by easy access around the preparation and is the best treatment for periodontal health.
The margin of the restoration is brought as close to the bone as possible without impinging on the attachment apparatus. It is extended beyond any readable or unreadable bevel onto uncut tooth structure.The overlap of the casting on the root surface is well tolerated as long as the margins are thin and fit properly with no gaps. In fact the enamel overlies the dentin in the very same manner! The casting seals the tooth in the same manner as a mason jar cover, which is the best means of preserving food from bacterial spoilage known to mankind. Tens of thousands of full coverage restorations prepared in this manner since the 1930s have demonstrated an exceedingly low percentage of decay no matter what the restorative material. The crown with a full-shoulder and long apron also exhibits superior retention, and is, in fact, routinely worn with Vaseline ointment or rubber (Opotow trial). Even wearing these restorations for long periods of time on a temporary basis does not appear to significantly increase the incidence of decay.
It is important to recognize that because all ceramic (butt-joint) restorations cannot be cast accurately enough and thin enough for aprons, they cannot offer the superior advantages of fit and protection against decay.
Examining a New Treatment
Any new treatment should satisfy important criteria before being routinely used on patients. Both the patient and the Doctor can be hurt by careless experimentation. When the price of gold skyrocketed in the 1980's, for example, nonprecious materials seemed very attractive. These materials had the advantages of being inexpensive and exhibiting great strength in sections as thin as .1mm. After fabrication of more than 100 units of nonprecious restorative dentistry, it became apparent that the porcelain did not really fuse to the metal, it did not cast accurately (every casting had to be reamed to fit the die) and it was difficult to solder properly. All of these units had to be remade--a tremendous waste of time and money for both Doctor and patient.
Trying something new is important for learning and for ultimately providing better patient care, but the decision to try something new should be based on these criteria:
(a) First, it does no harm. The Hippocratic Oath always applies. It is important to select the right type of patient and to know that no harm will be done in the event of failure.
(b) It conforms to accepted principles of health.
(c) It has scientific evidence for its efficacy. The CAPTEK website--www.captek.com has a list of scientific articles from the past years that discuss the benefits of the CAPTEK material.
(d) Reputable individuals recommend its use.
Fig. 18: Scientific articles documenting the efficacy of CAPTEK
Any new material that is tried must be evaluated against current standards and compared honestly.
Fig. 19-34: This patient's original crown with the post attached came out. A new direct post was made for this tooth. Notice that the post portion is made first, then an ion crown form is filled with red duralay and inserted to ideal position over the post. The clinical crown is prepared with depth guides in the same manner as a regular tooth. This technique ensures that the post will be properly designed for an ideal restoration. A porcelain to metal jacket was made for this tooth first. Then a CAPTEK coping was made using the same models. Notice the CAPTEK crown is much thinner and conveys more translucency than the PFM crown.
The CAPTEK Material
The CAPTEK restoration fulfills all of these criteria. It is essentially the same chemistry as Renaissance (predominantly gold and platinum), which has had overwhelming success. Like Gold, PFM and Renaissance restorations, CAPTEK can be fabricated with a long apron for superior fit and protection against decay. Studies show that it is highly biocompatible and promotes health, and the material has been used with success for over 10 years.
CAPTEK Fabrication
Fig. 35-42: Briefly, The original dies are duplicated with the CAPSIL Duplicating Silicone Material. [This impression material is extremely accurate and it can also be used to make duplicate epoxy dies or make dies of underlay copings for the fabrication of overlay restorations.] The impression is poured with the refractory die investment to make the refractory dies. The CAPTEK P and G materials are applied to the refractory dies and fired in the oven to produce the CAPTEK copings. These copings are extremely strong. They should fit the original dies perfectly. If they are loose, they can be swaged to the original die for perfect fit. As with any investment, tightness of the castings may be improved by adjusting the liquid rations.
How does CAPTEK compare with other Restorations?
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(A) Beauty: CAPTEK is one of the most aesthetic restorations around. It can be made much thinner than PFM restorations and slightly thinner than its Renaissance cousin. Unlike Renaissance, which had a silver appearance, |
| CAPTEK has a rich golden color thatcontributes warmth to the porcelain. (Captek vs Renaissance Fig. 55) -> |
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| Unlike all ceramic restorations, CAPTEK colors are not affected by the color of the cementing medium. With proper tooth preparation, CAPTEK restorations provide the operator with complete control over tooth shape, size and color. |
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(B) Strength: CAPTEK restorations are strong, and--like Renaissance--there is a low incidence of porcelain breakage. The CAPTEK copings, however, are much stronger than the Renaissance copings. They can be used as transfer copings for the master impressions. By contrast, Renaissance copings were easily bent and had to be opaqued or painted with acrylic prior to use as transfer copings. CAPTEK copings can also be splinted to other copings or to pontics with adequate strength.
Fig. 43 -46: Note that CAPTEK is strong enough to resist strong occlusal forces. This patient has a strong bite, marked occlusal wear, and very little room for the restoration. Endodontics was not done on this tooth. Note how the margins mirror the bone in the X-Ray.
(C) Fit: Renaissance copings had the best fit possible because they were fabricated with a direct technique--swaging directly on a die before processing. The Renaissance technique was the simplest and required the fewest materials. CAPTEK, by contrast is fabricated by an indirect process that requires a refractory investment die before processing. With duplication of dies there is always the likelihood that can be introduced. Indeed CAPTEK copings may fit more loosely than Renaissance copings. However, CAPTEK copings can be swaged on the original die to ensure similar fit. Altering the water/liquid ratio of the investment can also yield tighter copings if they are too loose.
(D) Health: CAPTEK copings are precious, inert and biocompatible. Studies show that the CAPTEK material promotes health by reducing the adherence of plaque and bacteria.
Fig. 47-51: CAPTEK restoration of a lateral incisor. Note that the CAPTEK coping is used as a transfer coping for the master impression.
Fig. 52-56: The CAPTEK Coping can be used as a transfer coping for a bite tray impression. Note how the margins of the CAPTEK coping relate to the bone in the finished X-Ray.
Fig 57-62: Sometimes a bite tray can't be used. In this case acrylic is placed over the CAPTEK coping and the patient closes. A quarter section rubber impression is taken on the lower and a quarter section alginate impression is taken on the upper. The acrylic acts as a seat for the CAPTEK coping and facilitates mounting of the models.
Summary
For more than ten years, the CAPTEK Restoration has been one of the most aesthetic full coverage restorative materials available to dental practitioners. The CAPTEK material can be configured as thin as .1mm and affords the operator complete control over the shape, size and color of the restoration. Although the laboratory procedures are indirect and time consuming, CAPTEK copings can be configured to provide excellent fit, retention, and protection from recurrent decay. Studies have shown that CAPTEK copings reduce the accumulation of bacterial plaque and contribute to periodontal health. CAPTEK restorations also have substantial strength and demonstrate a remarkably low incidence of breakage.
©Copyright 2003 by Edward Feinberg, DMD
