April 1, 2015
by Bob Margeas, DDS
Minimally invasive dentistry is a buzz word that means different things to many clinicians. One dentist may think a ¾ porcelain veneer is conservative, where another thinks it is too destructive of tooth structure. Over the last several years technological developments have allowed clinicians to be more respectful of tooth structure. GV Black’s classification of cavity preparation was based on the restorative needs of the material. It was necessary to create resistance form and retention form so the restoration would not fall out. More tooth structure was needed to be removed to produce converging walls and placement of retentive grooves.1,2 When Black proposed these principles and his classification system of cavity design, dentists were more focused on controlling caries and not on the scientific knowledge of the disease.3,4
Today, dentists should have as their clinical objectives: prevention, preservation, and integrity in making the right decision for their patients. The primary objective of the clinician is to prevent the placement of the initial restoration.5 The most minimally invasive procedures include remineralization, sealants, and preventive resin restorations that requires the least amount of tooth removal. The patient’s diet, oral hygiene, fluoride use and regular recare help reduce dental caries. This preventive approach provides the patient and clinician an opportunity to reevaluate the outcome of the preventative measures and possibly reduce the potential for invasive intervention. Furthermore, this process involves educating the patient and involving them in the treatment decisions, which may result in acceptance of appropriate preventive and restorative strategies in caries management, and improved patient compliance and oral health.6
When a decision is made that a restoration is necessary, the clinical objective is to preserve as much tooth structure during the preparation as possible. With the ability to bond to tooth structure, adhesive preparation designs should be based upon the conservation of tooth structure and utilizing adhesive restorative materials.7 The conservative concept of the adhesive tooth preparation requires a biologic approach,8 which represents a key component to adhesive dentistry.9 The adhesive restoration does not require as much volume to resist clinical fracture which enables a more conservative preparation design.10 This conservative approach hopefully minimizes the restoration and replacement cycle for the patient over their lifetime. It has been demonstrated that smaller restorations can have an increased clinical performance and lifespan.11
Being able to bond to tooth structure has changed the playing field of dentistry. Adhesive dentistry has allowed more conservation of tooth as stated earlier, but materials are being improved with more physical, mechanical and optical properties similar to tooth structure.12 Restoring the natural dentition with bonded composite or porcelain reinforces the natural tooth and restorations almost as if nothing was done to the tooth if the preparations are conservative and bonded, as shown by Pascal Magne, DDS.
Minimally invasive dentistry is an obligation we have to offer our patients. The following case will demonstrate what we try to do in our practice on an everyday basis. The procedure is not only conservative but done in a responsible manner. This will allow the patient to have the longest lasting restoration with minimal treatment necessary in the future.
A 25-year-old patient presented to my office for a consultation because of the spaces between her teeth. She had previous orthodontic treatment, which you would never have guessed by the final results obtained. There were no upper bicuspids present. The full mouth smile is in Figure 1. The retracted smile is in Figure 2. The patient had a previously placed bonded metal bridge from the upper right first molar to the upper right cuspid but it had fractured (Fig.3). There was also a small space mesial to the upper left first molar and distal to the cuspid (Fig.4). A diagnostic wax up was done so a lingual matrix could be used to guide our layering (Fig.5). Teflon tape was placed on the lateral incisors to prevent etch and adhesive from bonding the teeth together. The central incisors were first etched and a universal adhesive was placed on the teeth, air thinned and then light cured for 15 seconds (Fig.6). The two centrals were built up first at the same time utilizing a single shade technique (Fig.7). Matrices were used as an instrument to pull the material interproximally. The teeth were slightly shaped prior to starting the lateral incisors (Fig.8). All the teeth would be finished and polished as a group once the build ups were completed. Composite was placed in the lingual matrix and placed on the teeth again to aid in building the lateral incisor (Fig.9). Once all the buildups were completed finishing discs and burs were used to shape and polish the restorations (Fig.10). Interproximal finishing strips were used to make sure there were no rough areas (Fig.11). The final full smile is shown in Figure 12. The close up is in figure 13. Right and left lateral views are in Figures 14 and 15. After the anterior teeth were restored with composite resin the upper right molar was prepared due to recurrent decay and a cantilever zirconia bridge was cemented. To close the space between the upper left molar and cuspid a direct resin cantilever was bonded to the molar. Figure 16 shows the completed case at two years post op. A close up of the cantilever composite pontic is shown in Figure 17.OH
Bob Margeas is a Board Certified by the American Board of Operative Dentistry and is an adjunct professor in the department of operative dentistry at the University of Iowa College of Dentistry. He is on numerous editorial boards and lectures and performs hands-on courses internationally. He maintains a private practice in Des Moines, Iowa.
Oral Health welcomes this original article.
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