April 1, 2003
by Lynn Jones, DDS
Beautiful porcelains and strong bonding materials have made excellent cosmetic dentistry possible, but the true artistry is in the smile design and one of the most important elements of good smile design is the gingival contour. In order to achieve a beautiful smile design the contours of the teeth and gingiva must be harmonious with the patient’s lips and face. Gingival recontouring can be very simple and predictable if it is well planned and is respectful of the biologic width. This article will demonstrate how to accomplish a successful relationship between the tissues and restorations.
Cosmetic dentistry has traditionally focused on the teeth. In 1985 Dr. Frank Spear discussed the concept of the aesthetic contribution of the gingival contours to the dental reconstruction in his seminars. Soon dentists all over the country began thinking in terms of pink and white when planning for a cosmetic reconstruction. Paying attention to the aesthetics of the negative spaces is as important for a successful result as looking at the teeth themselves. With this redirected area of focus comes a different set of challenges which include determining how far up the root we can place the margins, the impact that has on biologic width, papillae, aesthetics, overall stability and ultimately the long term health of the tooth.
Determining the desired level of the gingival margin is based on several elements. The first criterion is the aesthetics of the smile. From the basic principles of smile design as presented in Dr. Gerard Chiche’s text and others, the incisal edges of the upper anterior teeth should form an arcing line that is parallel with the inner edge of the smiling lower lip, if the lip is symmetrical. The same is true for the gingival margins of the upper anterior teeth and the upper lip (Figs. 1a & b). This is especially true for the approximately 80% of the population that does display some gingiva.1
A tissue irregularity can be a devastating flaw in an otherwise beautiful smile (Figs. 1e, f, g & h). Even if the teeth look attractive, asymmetry, awkwardly proportioned teeth or an excessively “gummy” smile can significantly distract from the harmony of the smile.2
Several gingival configurations are aesthetically pleasing. Ideally the maxillary canines and central incisors should have their gingival apices at the same level and the lateral incisors should touch or fall slightly below the imaginary line connecting the apices of the canines and the central incisors (Figs. 1a & b).
An acceptable alternative, especially in class II patients, is the ‘V’ formation where two imaginary lines connecting the apices of the anterior teeth come to a ‘V’ between the two central incisors (Fig. 1c). Minimal gingival display is considered to be more aesthetic than excessive gingival display (Fig. 1f) or no gum display (Fig. 1d). Ideally the inferior border of the upper lip when smiling should rest at the level of the apices of the six maxillary anterior teeth. A range of up to three millimeters above the gingival zenith is considered aesthetically pleasing.3
Another factor to consider when planning the gingival height is the desired location of the incisal edge of the central incisors. In most cases this would be at or below an imaginary line that is half way between the upper border of the upper lip and the lower border of the lower lip, and resting on or above the inner border of the lower lip in a relaxed smile.
The average central incisor length is generally ten to twelve millimeters.4 These proportions should ideally balance out so the majority of the smile displays tooth, a very small part is the display of gingiva and less than half of the smile displays dark space. Ultimately, even with all these rules and measurements the overriding decision should be based on whether the smile looks right.
BIOLOGIC WIDTH AND OTHER CONCERNS
For the purpose of this article biologic width is defined as the minimum amount of space required between the alveolar crest and the crown margin for a healthy periodontal attachment. The average biologic width is approximately 3.5mm5-7,10 with some exceptions.
Tissue recontouring must be respectful of biologic width and the amount of support the tooth has based on root size and shape. It is also important to be aware of bone loss and dehiscences. Before planning any kind of crown lengthening procedure it is essential to review the radiographs. Post orthodontic root resorption, short, spindly roots or misaligned roots may be a contraindication to crown lengthening. It can be very difficult to get an aesthetic result with spindly roots because the shape of the gingival scallop becomes very narrow and almost pointed with an unnaturally wide based papillae.
Conversely teeth that have converging root proximity will have a very small papilla or none at all. A dehiscence is a contraindication for crown lengthening but very difficult if not impossible to detect on the radiograph. The best way to find a dehiscence is with periodontal sounding. Teeth with periodontal pockets and bone loss are contraindicated because it is impossible to control the amount of recession after the procedure has been completed.5,6
The most frequent challenge is the biologic width of the periodontium. It looks wonderful to go in with the electro-surgery unit or a laser and reshape the soft tissue exposing another 2 or 3mm of crown length. The tissue will look beautiful and healthy. Sulcus readings will be nonexistent and the height to width ratio on the tooth will look great. The result seems almost too good to be true. And it is. Within 3 weeks to 3 years the tissue will begin to proliferate and predictably attempt to reestablish the necessary 3.5mm of biologic width.
If a crown margin is in the way when this happens the tissue will become puffy red and tender with a tendency to bleed profusely if it is touched. The aesthetic result can be disastrous (Fig. 2). Consequently it is necessary to carefully plan ahead for a “gum lift” and have a simple method for performing not only the gingivectomy but also the osseous surgery to reestablish the biologic width.
PREDICTABLE CROWN LENGTHENING SIMPLIFIED
In earlier cases using a “gum lift” technique, the desired amount of crown lengthening was indicated on a model of the patient’s teeth. A vacuum surgical template was made to transfer the information onto the soft tissue. The surgeon marked the gingival outline indicated by the vacuum template and used that as the guide to perform the gingivectomy and the osseous surgery at the same time.
This method had some drawbacks because the accuracy of communication was somewhat deficient. The surgeon did not know exactly how the teeth would be shaped and where the exact location of the crown margins would be. This often led to the need for a follow up surgery to do minor touch ups. In addition, patients did not like it because it meant that they had to live with unattractive teeth that were often sensitive for months until the teeth could be prepared and provisionals fabricated.
It was a bit of an improvement to make a mock up over the teeth with acrylic or composite. This gave better information about the desired final outcome and led to better accuracy in the surgical phase but it still meant that the patient had to endure three additional months with unattractive and sensitive teeth.
Clients were demanding something better and it just seemed there had to be an easier way. This led to discussions with the periodontist who felt that she could predictably build a case to a biologic width of 3.5mm at the time of surgery and that the tissue level would remain where she placed it.5,7
The possibility of surgically placing gingival margins so predictably suddenly opened new doors. It meant that if the restorative dentist worked out the smile design, performed the gingivectomies, prepared the teeth, took the impressions and placed the temporaries to ideal contours, the patient could leave looking the way they had hoped and imagined. Seven to 10 days later the patient could go to the periodontist to have
the tissue flapped and the osseous margins placed 3.5mm from the margin of the temporaries (Fig. 3). At the end of 6 to 10 weeks the final restorations could then be seated.8 That would mean a happy patient because s/he always looked good from the very first appointment and the final gingival contours could be “perfect” after only one procedure with the periodontist.
Stephen Covey says in Seven Habits of Highly Effective People, “Start with the end in mind.” Although he is not a dentist I think his rule applies. Once you have a picture of what you want to accomplish you can work backwards to figure out how you are going to get there.
In my hands the simplest way to design the smile is with computer imaging. Although imaging is flat and does not handle color well it is effective for determining the relative sizes and shapes of the anterior teeth. The advantage of imaging is that it is easy for the patient to try on different looks (Figs. 4a & b).
Imaging is the ideal tool for aesthetically determining how high to position the gingival margin. When imaging, it is essential to keep the teeth lined up over the roots where they will be when the case is completed. Imaging is an excellent tool for communication with the laboratory and the surgeon when planning the case.
Other methods for planning the case include mock-ups on the teeth or wax ups on study models. All methods have advantages and drawbacks. Well-done mock-ups take more time and are especially time consuming for complex cases. Because they are formed right over the top of unprepared teeth they work best when larger sized teeth are desired.
The mock-up can even be made with a tiny flange right up over the gingiva to demonstrate the desired position of the gingival margin. This information can then be captured on photos and study models. Wax-ups can then be made into mock-ups; similar to the way they are made into provisionals. They will take less time but are more expensive. All three methods accomplish the smile design; imaging is just a smaller investment up front and gives the patient several choices. When the case moves into actual treatment the imaging can be sent to the laboratory for a highly refined wax-up.
The image selected by the patient was sent to the laboratory with the study models. Photographs of the retracted, smiling and full-face views assisted the laboratory with the desired gingival levels and overall contours. The imaged photo served as a guide for the laboratory technician to achieve the desired tooth form and comparative gingival heights. The gingival levels were confirmed with lines drawn on the models
Case 1 (Fig. 5) presented with hyperplastic gingiva and poor fitting crowns that violated biologic width. The swelling was noticeable and very disfiguring to her smile. She was so embarrassed by the swollen and overgrown tissue that she could not smile and had a very difficult time showing us her teeth. The over growth had occurred shortly after the placement of some previous cosmetic dentistry. She reported that everything was fine when she had the temporaries but when the final crowns were placed the tissue started to swell.
The bone levels appeared to be normal and the 4 to 6mm probing depths when compared to the radiographs all appeared to be pseudo-pockets, probably a result of the hyperplasia.
After determining the desired gingival position with computer imaging and the feasibility of crown lengthening, the design for a surgical stent was selected. In this case a cosmetic crown lengthening up to 4mm but just short of the crest of the alveolar bone was indicated. Because the desired gingival margin did not extend apically beyond the crest of the alveolar bone and the bone levels were normal it was possible to establish the gingival margins with a gingivectomy using electrosurgery.
Normally for cosmetic crown lengthening the gingivectomies would be on the facial surface only, but in this case the margins violated biologic width on the lingual surfaces necessitating circumferential gingivectomies (Figs. 6a & b).
The mounted models, patient photos and imaging were sent to the laboratory for diagnostic wax ups of teeth 7 through 10 (Fig. 7). The incisal edges were contoured similar to the image design. Desired tissue levels were communicated to the lab in millimeters apical to the existing free gingival margin. The laboratory waxed the teeth right over the gingiva to the desired apical levels of the final porcelain and scored the new margins into the stone to make them easier to read (Fig. 8).
The patient was shown how to brush and floss thoroughly and advised to do it every day. Because of the severe inflammation she was also prescribed a 30-day course of Periostat while the models were being waxed up for the provisional restorations.
A stone model was made to duplicate the diagnostic wax-up because hot vacuum-formed matrices melt the wax on the model when they are being made. It also protects the wax from excessive wear and tear if additional duplications are needed. A Sil-tech putty matrix was then made directly on the wax for accurate detail (Fig. 9). This putty matrix is usually the one used for making the prototype restorations because of its detail and accuracy. The clear vacuum matrix is not as accurate but it is useful for measuring preparation reductions, and tissue levels (Fig. 10).
At the preparation appointment, after the patient had been anaesthetized, the teeth were sounded by forcing the periodontal probe through the periodontal attachment down to the osseous crest to determine its level and the location of the CEJ. The tip of the probe was angled towards the tooth to feel the surface and prevent slipping past the bone (Fig. 11). The distance from the crown margins to the alveolus was determined to be an average of 2.5mm. All depths were noted in the patient’s chart.
In my experience most teeth sound at between 3 to 3.5mm on the facial surface using a marquis probe. Higher numbers may mean a long epithelial attachment, periodontal pockets, delayed passive eruption or as in this case, hyperplastic tissue. Lower numbers on the other hand could indicate a reduced biologic width.10
On the day of preparation, the gingivectomies were performed immediately after the soundings were recorded. The gingivectomies were performed to within 0.5mm of the alveolar crest with a Macan Electrosurgery unit using a straight wire tip set on 4. This machine was calibrated to cut and coagulate with no charring at this level. An internal bevel and small wire tip was used to minimize postoperative discomfort (Fig. 12).
The tip of the unit was kept away from the bone to prevent osteonecrosis. Light steady strokes were made at about the same speed as writing a note with a pen. Each pass with the tip was allowed at least 15 seconds of rest before repeating in the same spot in order to prevent an excessive accumulation of heat.
After the gingival recontouring was completed the teeth were prepared for the porcelain restorations (Fig. 13). All margins were prepared to within 0.5mm of the gingival margin. A gap between the preparation and the bone is necessary to allow room for easy to read impressions and for finishing the margins of the provisionals.
The Impergum/Permadyne impressions were taken before the temporaries were made. Retraction was not necessary because there was very little bleeding with the electrosurgery and all of the prepared restorative margins were exposed with the gingivectomy. The few remaining bleeding points were cauterized with the with the electrosurgery tip prior to the impression.
Once accurate impressions were made, the temporaries were made by filling the Sil-tech matrix with shade A-1 Protemp. The matrix was placed over all of the tooth preparations using the unprepared teeth and the palate for stops. With this technique margins will have overhangs because the position of the margin in wax was estimated through the stone gingiva on the model.
All of the teeth were prepared to draw with one another so that the provisional slipped right off of the
preparations in a single piece similar to a bridge. This indirect method allowed access for trimming and working out the aesthetics of the marginal contours. The temporary was also removable so the tooth preparations could be checked periodically during the three-month healing process.
The gingival embrasures in the temporaries were enlarged for easy access so that the patient was encouraged to follow through on her home care. At this stage we were emphatic about oral hygiene and cautioned that we would not deliver porcelain in the presence of any bleeding. The margins were trimmed to fit exactly without any overhangs so the tissue would heal properly.
After the gingivectomies and tooth preparations, the tissue began to heal rapidly. Within a week the patient was ready for the osseous recontouring. She was referred back to the periodontist (Figs. 4c, d & e).
At this stage all the periodontist had to do was reflect a facial flap leaving the papillae intact and recontour the osseous margins 3.5mm from the margins of the provisional restorations. Then when she sutured the flap into place she placed the soft tissue margin back to the edge of the preparations, which is a fixed and clearly marked line in the patient’s dentition. This method eliminates virtually all of the guesswork for the periodontist. The aesthetic goals are perfectly clear (Fig. 14).
The final restorations are placed at the end of the three-month healing period. At this time the patient’s smile is stabilized with aesthetically pleasing provisional restorations allowing the newly positioned biological width to mature (Figs. 15a & b).
The patient satisfaction with this simplified direct approach to combination porcelain restorations and gingival recontouring is very high. They get to see their desired results immediately. The predictability and aesthetic control maintained during all phases of treatment make this procedure less stressful and more satisfying to deliver. This builds trust with your patient and subsequently leads to more referrals.
For the most successful outcome it is essential to plan the procedure with the referral to the periodontist already in place before any of the actual tooth and tissue preparation begins. The gingival tissue looks so healthy after two weeks of healing that the patient and even some periodontists may deem the osseous procedure unnecessary.
This, however, is the best time to perform the procedure to obtain the most predictable outcome. The tissue is healthy and there is no bleeding. Also in the unlikely case that any post-surgical recession does occur, it is a small matter to remove the provisional and drop the margin of the preparation a little bit to cover the exposed root before taking the impression. If the osseous procedure was postponed until after the porcelain was seated, the same situation might involve remaking the porcelain.
Getting the best results depends on excellent communications with all of the members of your team. If the periodontist is unfamiliar with this technique make sure that he or she understands your intentions and treatment goals. A good periodontist will appreciate your leadership, your clear directions and the desire to achieve the highest standard of excellence.
Dr. Lynn Jones is an accredited member of the American Academy of Cosmetic Dentistry. She is the founder and director of “Aesthetics, a Live Patient Continuum” for the University of Washington, Department of Continuing Dental Education. Dr. Jones maintains a full-time cosmetic and reconstructive dental practice in Bellevue, WA.
Author’s Note: To facilitate clarity of this article, figures 11, 14, 15a & b have been inserted from another case for illustrative purposes.
Oral Health welcomes this original article.
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