February 9, 2009 | Web Exclusive
Clinical 360°: Cosmetic/Restorative
Minimal prep, minimal results?
Dr. Gary Radz and our Team Lead discuss different philosophies and techniques regarding Minimally Invasive Dentistry.
By Drs. Gary Radz and Robert Lowe
The Set-Up
“When the term MID is mentioned to clinicians, their immediate thought is usually micro-engineered cavity preparations and maximum conservation of tooth structure. In fact, MID covers a wide variety of procedures, not just cavity preparation; and involves techniques that not only are very conservative in nature, but from the surgical side, offer faster healing times with greater comfort for the patient. This approach does not apply ‘across the board’ for all patients and all clinical situations. We still have to be the doctor! But when indicated, a minimally invasive approach can yield maximal results.”—Dr. Robert Lowe, Team Lead
Minimally Invasive Dentistry (MID) is a “hot topic” in dentistry today. Advances in diagnostics and technology have allowed the dental operators’ “microscopic world” to become even smaller! G.V. Black’s edict “Extension for Prevention” in most cases no longer applies, given the state of dental restorative materials available today that can be bonded predictably to tooth structure.
Since dentists, as a group, are generally very conservative by nature, it would seem that this minimally invasive approach to restorative treatment would be second nature. However, some voices in the profession present somewhat unrealistic views of just how conservative we can be clinically and still have a predictable, long-lasting result for the patient. This creates a state of confusion for many dentists who practice in the real world, delivering everyday care. So the question becomes: How minimally invasive can we be?
CASE IN PICTURES: SLIDESHOW
(Refer to slideshow for figures)
Dr. Lowe’s components
1. Operative dentistry
Cavity preparation has become more minimally invasive for a couple of reasons. First, early diagnosis is made easier with cavity detection devices, such as Kavo’s DIAGNOdent (kavoamerica.com), which identifies early decalcification beneath pits and fissures that may not necessarily “stick” with an explorer (blunt probe, after several trips to the autoclave). The doctor still must use clinical judgment as to whether intervention is indicated. However, many carious lesions can now be detected in their infancy. Should the lesion need to be prepared for a restoration, devices such as fissurotomy burs, or hard- and soft-tissue dental lasers, such as Biolase’s Waterlase MD (biolase.com), allow the operator to indeed be minimally invasive when preparing a cavity for restoration (Fig. 1). Even with fissurotomy burs, preparation into dentin requires local anesthesia for patient comfort. Waterlase MD, in many cases, allows the operator to prepare a cavity into dentin without the use of local anesthesia, thereby being even more minimally invasive than conventional operative therapy.
2. Esthetic periodontal/restorative procedures
Closed-flap crown lengthening for minor biologic width encroachment and/or facial esthetic crown lengthening to create symmetrical gingival levels now can be approached in a minimally invasive fashion, creating faster healing and treatment times for those types of cases with predictable results. The use of an all-tissue laser makes this possible. Esthetic gingivectomies that do not involve bony correction often can be done using the Waterlase MD without anesthesia (Fig. 2).
3. Removal of ceramic restorations
Until now, removal of ceramic restorations from the tooth for whatever reason often involved removal of more sound tooth structure because of the instrumentation used (e.g., diamond burs) to cut the restorations off. Using a laser, many of these types of ceramic restorations can be successfully removed without removal of additional tooth structure. All-tissue lasers can be used to separate the ceramic from the underlying cement layer. Often then, the cement can be polished off the tooth surface with a composite polishing point or cup leaving the original preparation unaltered (Figs. 3 and 4).
Dr. Radz’s components
Dr. Lowe has pointed out several areas where minimally invasive concepts have been proven to work as well as some areas of caution to be considered.
In many areas, Dr. Lowe and myself have similar practice philosophies. However, the following are further considerations in the area of minimally invasive dentistry.
1. Indirect posterior restorations
Minimally invasive dentistry concepts certainly can be applied to how we consider restoring posterior teeth that are significantly compromised.
The use of onlays rather than crowns allows us to minimize the removal of tooth structure, yet allows for the desired end result of replacing and strengthening a structurally compromised posterior tooth. Consider a molar with a large MO amalgam and a fractured ML cusp. It is commonplace, and not incorrect, to place a full coverage crown. But, if the distal half of this tooth is intact, uncompromised and shows no evidence of posterior decay, wouldn’t an MOL onlay be a much more minimally invasive procedure, yet still produce the desired end result? I believe such an onlay restoration would be a much more conservative option. Using modern ceramics or indirect composites, a highly esthetic and strong restoration would provide an excellent treatment alternative to the above hypothetical situation.
To further pursue the subject of onlays, the inclusion of gold onlays is appropriate when discussing minimally invasive procedures. Gold by its nature requires the least tooth reduction of any material used in dentistry. So although it cannot compete with the esthetics of porcelain or indirect composite, it certainly does compete (if not exceed) in the areas of longevity, strength, and predictability. In my practice, gold is always given as a treatment option for any indirect restoration to be placed on a molar.
2. Posterior single tooth replacement
In the situation of a single missing tooth, implants not only provide the ability to be minimally invasive, but in respect to tooth reduction, implants actually can be non-invasive.
Our current surgical abilities with sinus lifts and bone grafts allow us the ability to replace a single missing tooth in a majority of clinical situations. This ability not to involve adjacent teeth is a major advantage in our attempts to “do no harm,” yet provide the patient with a long-term clinical solution.
In cases where an implant is unable to be placed or a patient declines the implant option, we have the ability to create “hybrid” bridges. These hybrid bridges provide the patient with a fixed prosthetic solution without the need for full coverage of the abutment teeth. Many hybrid designs exist in dentistry. The more popular examples include the Maryland bridge, Encore bridge and the inlay bridge. Each of these require minimal, partial preparation of the abutment teeth, thus allowing a more conservative restoration.
3. Direct anterior restorations
Today’s modern composite materials have the ability to create highly esthetic results without the need for a porcelain restoration. With proper understanding of the composite materials and the correct layering of color/shade combinations it is possible to create a natural appearing direct composite restoration.
Whether due to disease or trauma, composites can be used to replace missing tooth structure in a predictable and cosmetic fashion. Oftentimes, the preparation for these restorations can be more conservative than the preparations for a indirect restoration. For many years, dentists have believed that to get great esthetics, they needed the assistance of their ceramist. Recent developments in composite technology should help change this thinking. Modern composite materials have the array of shades/opacities/translucencies available that can successfully mimic natural tooth structure. Additionally, the strength characteristics currently available allow for composite to be far more predictable in the anterior region.
Conclusion
It is clear from the many examples given here that the most important aspect of a “minimally invasive” approach to restorative dentistry involves treatment choices, such as bridge versus implant, crown versus onlay, or a minimal prep versus “no-prep” veneer, to name a few. Esthetic and functional predictability along with the conservation of natural tooth structure represents a “realistic” approach to “minimally invasive” philosophy.
The take-aways
With proper case selection, a MID approach can yield maximal results.
MID covers a wide variety of procedures, not just cavity preparation.
| Team Lead Dr. Robert Lowe
About the Author
Dr. Gary Radz maintains a private practice, Cosmetic Dentistry of Colorado, in Denver. A graduate of both AEGD and GPR residency programs, Dr. Radz has been an associate clinical instructor for several post graduate dental education institutions. Currently, he is an associate clinical professor at the University of Colorado School of Dentistry. For the last 14 years he has lectured internationally about materials and techniques used in cosmetic dentistry. He has published more than 125 articles and serves on the editorial board of eight dental publications, including the Journal of Cosmetic Dentistry. Dr. Radz serves as an evaluator for Reality Publishing and is a clinical consultant for numerous dental manufacturers. His photography has been published on the cover of five different dental journals and he has provided photography for educational and promotional purposes to dental manufacturers and dental laboratories. He may be contacted through his Web site, www.garyradz.com.
Other Team Member
| The products that appear in conjunction with this article are for illustrative or informational purposes only. Their inclusion does not denote endorsement by the author of this article. |
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