By Tom Orent, DDS
I've often mused about the "virtual shutdown" of my practice if someone suddenly were to remove all of my computer chips. We really are that dependent upon technology today. What's the most important advance in the last decade? What do we really depend on ... so much so that we would be immobilized without it? Computer chips drive our practice-management systems. Do without them? Not easily, but we could get by with calculators, paper appointment books, and ledger cards.
How about intraoral camera systems? I'd really hate to give them up! But we'd make do. Air abrasion, digital X-rays, computer-assisted imaging (CAD), CCD chips in operatory microscopes, advanced technology PAC lights ellipse the list is endless. I use each of the above every day. Yet, for every single one of these incredible advances - although I would hate to do without them - there are alternatives. These alternatives would allow me to deliver the same quality of care, but with a whole lot more effort.
However, the impact dental adhesives have had on my practice outweighs the combined impact of all the other technology combined! I no longer can picture my practice without adhesives - 99 percent of my single-unit (and up to three-unit) fixed-bridgework dentistry depends upon adhesive dentistry. Back in 1985, I started experimenting with adhesive-bonded, full-porcelain crowns. I remember a friend of mine (a prosthodontist) warning me to be careful about going out on a limb with adhesives. What if the crowns all broke or fell out? I also remember how incredibly beautiful they were in comparison to the porcelain-fused-to-metal restorations (PFMs) of the day - and they didn't break or fall out any more or less than PFMs. In fact, the advances in adhesives over the last decade have made this the most exciting time in the history of dentistry.
What are the advantages of adhesive dentistry? Here are a few areas that come to my mind.
The esthetic beauty of all-porcelain adhesive dentistry is the number one factor persuading me to do little else ... in almost any circumstances. The warnings of yesteryear are no longer valid. Certainly, the patient should be educated regarding the slightly higher likelihood of failure by fracture of porcelain vs. all-gold - but it is just that, slightly higher. I personally would rather have any of my teeth retreated, if needed, than go back to any all-gold restorations. I proudly wear 16 posterior units of Empress and Concept restorations. The esthetics of what we can accomplish today is nothing short of astounding.
I don't think twice about telling folks that we can recreate the natural beauty of almost any dentition today. A few years ago, I received a call from a patient in emotional distress. Her 20-year-old son, Eddie, had just fractured his two front teeth pretty badly. He was playing hockey at a local arena. One of his opponents came up from behind him and pushed him face-first into the ice. From what she described, it was like the classic "Coke bottle fracture." I was thrilled to be part of a profession that allowed me to confidently tell the mother not to worry. I could assure her that the final outcome of treatment would restore her son's natural smile and beauty. In fact, I was confident (and told her so) that when we finished, no one would be able to tell that anything at all had been done!
Eddie arrived at the office with his maxillary central incisors absent. They had been lost on the ice in the accident. Periapical radiographs helped us to determine that there were no additional injuries. All was normal, except the gross oblique fractures barely shy of the pulp. The teeth were prepared using the fracture lines as my incisal reduction (I don't usually go that far toward the pulp, so we were all set for clearance.) The remaining portions were prepared labially and with sufficient dogleg or elbows interproximally to hide the margins. Impressions were taken, temporaries were fabricated, and one very happy mother and son headed home to make up lost sleep. The final result was spectacular - it was impossible for anyone to tell that anything had ever been done. Even the finest ceramist in the world (and I've worked with several of them) would have had difficulty matching the esthetics we achieved if their talents were restricted to the use of porcelain and gold. Of course, major additional tooth reduction was averted thanks to adhesive dentistry.
Eddie's case was typical of the majority of adhesive dentistry - conservative. We routinely save entire walls of teeth, cusps, and other supporting anatomy that, without adhesive dentistry, would very likely have been doomed to preparation - in the name of retention.
Of course, adhesive dentistry isn't limited to laboratory-fabricated restorations. Air-abrasion "microdentistry" has opened up a whole new world in dental practice. Occlusal pit, fissure, and groove caries are routinely discovered today by dentists using a number of diagnostic alternatives. These alternatives in clude air abrasion to clean out the grooves for easy inspection; fissurotomy burs that allow minimally invasive wid ening of debris, stain and bacteria-laden fissures; and KaVo's DIAGNOdent - a computer-assisted, laser diagnostic tool that helps the doctor identify areas of pit, fissure, and groove caries objectively. (It also helps the patient see that caries exists in otherwise asymptomatic "healthy-looking" teeth.)
Regardless of how we come to the conclusion that caries exists, we are able to remove it ultraconservatively and replace the damaged tooth structure with remarkably miniscule adhesive-retained composite restorations.
In the early days of adhesive dentistry, we did not have extremely high levels of confidence in retention. Today, even my most severely damaged full-reconstruction cases can be achieved thanks to the modern miracle of dental adhesives.
These cases are not restricted to areas of limited function. A few years ago, a young female attorney presented at my office for care. Her dentition had been devastated by the constant acidic assault associated with binging and purging. Although she had overcome her emotional problems and ceased the damaging habits, the condition of her teeth were a reminder of the severe punishment she'd unleashed upon herself.
Her anterior teeth were completely devoid of enamel on the lingual surfaces. The rest of the mouth was not much better. Since all of her teeth were damaged, a full-mouth reconstruction was required. The anterior maxillary devastation was such that it required six endodontic treatments. The day we placed the anterior Empress, this young lady cried like a baby. Her parents had urged her to seek dental care (and helped her with it financially as well). She told me that she could hardly wait to show her mother.
Through the American Academy of Cosmetic Dentistry's "Give Back a Smile" program, I met a young lady who, due to domestic abuse, had lost all six of her maxillary anterior teeth down to the gum line. Her posterior teeth were not far behind - only a few remained unscathed. We now are in the process of rebuilding her entire mouth with the help of adhesive dentistry.
Porcelain-fused-to-metal restorations in evitably foster adjacent chronic periodontal problems. Upon examining a pa tient with PFMs, you'll routinely discover mar ginal redness, bleeding, and poc keting to varying degrees ellipse all associated with the existence of the PFMs. It is difficult (though not impossible) to achieve imperceptible margins with PFMs. That insult to the biologic space/pocket is routinely the source of chronic periodontal infection. We could place all PFMs supragingival and alleviate the likelihood of periodontal problems. Of course, the esthetic concerns associated with PFMs supragingivally will, in most cases, rule this out as an option.
With the advent of bonded porcelain restorations, we no longer are concerned with the esthetics of an exposed margin. In fact, it's just the opposite. We routinely will place all margins supragingival with rare exception. Extremely natural esthetics can be achieved with bonded porcelain, regardless of the location of the margins. Ironically, it's the bonded porcelain restorations that most often can help us achieve seamless margins - margins that could likely live compatibly within the biologic space if necessary.
This is one area of frequent concern for many practitioners. A high number of the "Ask the Gems Guy" e-mails request information on decreasing post-operative sensitivity following adhesive dentistry. Two of my favorite leaders teaching the theory and technique necessary for high levels of success in adhesive dentistry are Dr. Bill Dickerson (www.lvilive.com) and Dr. Bill Strupp (www.strupp.com). Both go into great detail on methods of decreasing sensitivity.
If proper techniques are followed, post-operative sensitivity should rarely be a problem. Rather than try to reteach their courses, I'll touch on just a few of the more common reasons for sensitivity and how to avoid these pitfalls. This is by no means a comprehensive discussion of sensitivity. A comprehensive discussion routinely requires a significant portion of a full day's lecture.
Voids: If, when placing direct resin restorations, voids are left between the prepared dentin and the composite, there will very likely be sensitivity and potential catastrophic failure of the restoration. The simplest way to alleviate the possibility of incorporating voids under the restorations is to use a flowable composite as your first layer over the adhesive. There are differing opinions on the best way to perform this technique. Some doctors will place a thin layer of flowable composite, cure it, and then place the direct-fill resins. Others have suggested that the above technique lends itself to voids, simply higher up into the restoration. Those doctors will place the flowable composite, followed by the regular restorative composite, without curing the flowable layer first. This forces the "packable" composite into the flowable and likely minimizes or eliminates the chance of voids anywhere within that area.
Incomplete cure: More than once, I've heard about Dr. Gordon Christensen greeting hands-on course participants at the door and checking their curing lights with a radiometer! In doing this, he found that most lights didn't perform to the standards he thought they should. The reasons for these performance failures include composite or other debris stuck on the tip, dirty filters, and bulbs that have gone past their prime life. Similar to amalgam fillings, curing light bulbs will appear to be working long after they've lost the ability to perform properly.
A radiometer or disc test can be used to make certain your curing lights are up to par. A simple disc check can be done by placing the curing tip against the end of a tube of composite and curing for your routine allotted time. After curing, dispense the composite and wipe away the uncured resin from the cured piece at the end. Although not highly scientific, you'll get a rough feel for the depth of cure at which complete failure occurs.
Dr. Michael Miller suggested in Reality magazine (an excellent source for the latest objective test results of cosmetic materials and devices) that we should triple the manufacturer's recommended cure times to be certain we've completed the necessary cure.
Inadvertent etching of root surfaces: Root surfaces often are assaulted by aberrantly placed etchant or during the washing of the etchant, as we try to rinse it away. In either case, post-operative root sensitivity is a common problem, but it can be avoided by exercising caution in the placement of the etch. However, even if we are careful in the placement of the etch, it still is possible that some etch will reach the roots during washing. Dr. Strupp suggests Superseal, which chemically binds potassium oxylate to the root surfaces. We use Superseal on all margins and root surfaces (even the root surfaces of the adjacent teeth) at the end of every adhesive dental restoration.
Implosion stress fractures: We know that resin will shrink toward the light source. Care and advanced thought should be given to the methods we use for layering and curing composite. Place increments along a single wall and cure through that wall to pull the resin in toward the light. The seemingly simplest of composite restorations - the occlusal composite - often can cause the most problems. Since the resin is surrounded on all sides by enamel, care must be taken to avoid placing a large enough increment of resin that contacts all walls simultaneously. If done incorrectly, the light will cause a rapid implosion fracture as the resin shrinks and pulls all the enamel/dentin walls in toward the center.
A discussion of adhesive dentistry would be incomplete without a warning regarding incompatibilities. In the early days of dental adhesives, systems were few and simplicity was the byword of the day. We were told that all adhesive bonding systems were compatible with pretty much any restorative resin we chose. Today, we know that is not the case. In fact, if we are not careful to research which restorative resins work best with each dentin bonding system, we may end up with anything from slightly decreased bond strengths to catastrophic failure.
Although my dentin-bonding system of choice is a fifth-generation system — Prime and Bond NT — I also use a fourth-generation system - Bisco All-Bond II - when placing composite-core buildups under crowns and onlays. Why? Den-Mat Core Paste (my choice for core buildups) is incompatible with fifth-generation dentin-bonding systems. In fact, many of the fifth-generation systems are less than adequate when used to bond auto-cure (paste a/paste b) resins. CRA published an excellent review of resin compatibilities in the summer of 2000. Consider reviewing their findings and comparing them to the combinations you are currently using in your office.
Focus on esthetics
The advent of adhesive dentistry has truly revolutionized the practice of our modern-day art. Esthetics rivaling nature's best conservation of natural structure more than ever before possible - as well as greater biocompatibility and virtual elimination of sensitivity - makes this a glorious time to be a practicing dentist. If you have yet to embrace the world of adhesive dentistry, consider making this facet of practice your focus for advanced continuing education. You, your team - and especially your patients - deserve the incredible rewards associated with the modern-day miracle of adhesive dentistry.
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