Written by Martha Cortes, DDS Sunday, 31 August 2008 19:00
Neuromuscular, bioesthetic, and functionally guided dentistry have not reinvented the wheel of cosmetic dentistry; however, with other occlusal theories they have helped to restore occlusion (function) to its proper place within the field of cosmetic dentistry. Too many dentists doing cosmetic dentistry today forget that function must be built into a new smile to obtain a successful long-term result. Cosmetic dentistry for the most part uses the patient’s habitual occlusion as a template upon which the new smile is built. However, the habitual bite many times is deteriorated and often is not highly functional.
THE IMPORTANCE OF FUNCTION
|Figure 1. Original smile, half face. Note only maxillary teeth are visible.|
By understanding this alone, the cosmetic dentist can make great strides as a practitioner. Cosmetic dentistry should not be viewed solely as an aesthetic enhancement of the teeth and smile; it depends upon the functional condition of the oral cavity and the cranium. Form and function are inherently tied together and cannot be separated. Therefore, any imbalance in the oral cavity will affect the cosmetic work by debonding and/or breakage of the prosthetics and/or the teeth.
Eighty percent of patients that I?have seen who want cosmetic dentistry have some form of occlusal disease. These patients in general are asymptomatic; however, certain signs may indicate underlying problems, such as a large submental crease, a collapsed lip line, and/or a jutting lower lip. There also can be a collapse of the lower one third of the face, which indicates a vertical discrepancy between the upper and lower teeth. I have seen beautiful cases where both arches were cosmetically en-hanced and the patient did not have any problems when smiling brightly. However, when the patient is fully closed, the lower arch is barely visible, as the length of the upper arch overshadows it. This indicates that the Shimbashi measurement is not sufficient to support a cosmetic overhaul, as the teeth—especially in the lower arch—are too short. (Note: The Shimbashi measurement is the distance from the dentinoenamel junction (DEJ) of tooth No. 9 to the DEJ of tooth No. 24 when the patient’s mouth is fully closed without any manual manipulation.)
EXAMINING THE PATIENT FOR SIGNS OF OCCLUSAL DISEASE
We need to look for signs to indicate quickly whether a cosmetic case has critical functional components as well. Finding answers to the following questions will help you clarify your patient’s condition:
- Is the Shimbashi measurement less then 17.0 mm?
- Are the patient’s eyes and ears parallel to the horizontal plane of the earth?
- Is the maxilla’s midline dramatically different than the facial midline?
- Are the posterior teeth flat and without occlusal stops?
- Is the patient’s maximum opening range of motion less then 35.0 mm?
- Is the range of motion for lateral excursions less then 10.0 mm?
- Is the facial midline aligned or is it dramatically off?
- Does the mandible deviate away from the patient’s midline during opening and closing?
Depending on the findings when asking these questions, if there is an indication of occlusal problems, the bite needs to be tested further. This may initially involve a sonogram, jaw tracking (computer analysis of jaw opening and closing movements), and a transcranial x-ray during the consultation. More testing is done once the case is accepted and before any major work is done.
By examining, diagnostically evaluating, testing the bite (occlusion), and ensuring its functionality before the operative phase begins, one can ensure that the prosthetics placed will have an optimal prognosis. Otherwise, prosthetics can fail prematurely or the patient’s bite can worsen—often dramatically and with acute and/or chronic pain. Cosmetic dentistry has the great po-tential of treating the oral cavity in its entirety, rather than just beautifying it. It can restore function and stem the loss of vital teeth and supporting structure that is part of aging, poor hygiene, infection, and/or poor dentistry.
The oral cavity and the body are very adaptive; however, this does not mean that any and all occlusal/functional changes are healthy because the body has adapted to them. The body is built to survive at all costs and will sacrifice function and anatomy to do so. In addition, the habitual bite has not evolved. Rather, it is the result of entropy and disorder. Order has been lost to aging, poor hygiene, infection, and/or poor dentistry. In essence, the functional-cosmetic dentist reintroduces order and eliminates disorder from the habitual bite (and the oral cavity) by correcting the bite.
CHANGING THE PHILOSOPHY FOR AESTHETIC TREATMENT
A philosophy of cosmetic dentistry that promotes purely cosmetic concerns without thought to functional considerations will simply procure a quick and immediately pleasing result. It is not concerned with the consequences of building a smile on a foundation that has formed as the result of negative forces. If the foundation is weak and structurally uneven, newly placed cosmetic work will not last as assumed. If the teeth are severely worn and broken down, the lost vertical anatomy must be restored to distribute the forces of occlusion evenly and in an axial direction, perpendicular to the teeth. Otherwise, pathologic loading forces will continue to destroy the teeth and any new restorations.
BUILDING AN AESTHETIC CASE ON A SOLID FOUNDATION
Figure 2. Original smile, right retracted.
|Figure 3. Original smile, left retracted.|
In addition, before any teeth are restored and the occlusion is corrected, all infection must be eliminated from the oral cavity. Otherwise, we are again building on a weak foundation (Figures 2 and 3). Infection can be eliminated many different ways, but one of the best ones is laser technology. I have been using lasers for the past 14 years, successfully eliminating infection and the biofilms that make infection so resilient against antibiotics, antimicrobials, and other disinfectants. A laser is site-specific, and as a result it can precisely target the area of infection, unlike antibiotics and anti-microbials, and eliminate biofilm protection. However, one must know how to use laser technology as well as which laser to use.
Lasers are similar in how they produce light, but they vary by using different wavelengths. This can produce different results, thereby making one type of laser system better than another for certain or unique applications. As such, in functional cosmetic dentistry, it is better to have a variety of lasers to treat specific conditions as needed and to speed up the process. If one is in a general practice, a simple diode laser should be enough. If, for instance, a patient has periodontitis and wants to have his or her smile restored, the periodontal disease can easily be treated with an Nd:YAG laser (Periolase MVP-7 [Millennium Dental Technologies]) with minimal discomfort and a quick recovery. This allows the dentist to begin the restorative/aesthetic phase of treatment soon after the laser treatment is completed. (Conventional periodontal treatment without a laser requires approximately 3 months for healing, and sometimes the aesthetic results of the surgery are less than desirable). The laser can also be used to eliminate bacteria, biofilm, and infection. At the same time, the doctor can sculpt the gingival tissue (with little or no recession postoperatively) for a more harmonious smile design. If the patient requires endodontic or caries treatment, an Er,Cr:YSGG 2,780-nm laser (BIOLASE) would be a better choice.
Figure 4. Original intraoral maxillary arch.
|Figure 5. Post CEREC and interim fixed orthotic of phase one.|
Kathy, a woman in her late 50s, presented for a cosmetic makeover and periodontal treatment with a laser. The patient had caries and calculus throughout, moderate periodontitis, general bone loss throughout, and failed root canals (Figure 4). All her second and third molars were missing. She did not visit the dentist regularly, and had veneers that were 31-years-old and had fractured multiple times. They were repaired and/or rebonded many times. Caries surrounded the margins of all the veneers.
Although plenty of posterior space was available bilaterally, the lower anteriors were extremely crowded. They displayed substantial wear, and teeth Nos. 23 to 25 displayed severe lingual inclination. Tooth No. 24 was in a severely labialized position with a mucogingival attachment problem, the mandibular arch was narrow, and the remaining posterior teeth were lingually tipped. The teeth of the lower arch were severely maloccluded and malaligned, the maxillary anteriors were splayed, and the upper right and left arches canted (on different planes) upward and away from the centrals (Figure 5). This indicated that the malocclusion was not solely in the mandibular portion of the jaw, but also in the cranial portion, which could cause physiological problems. An old, 3-unit PFM bridge between tooth Nos. 3 and 5 had almost no anatomy. Metal was exposed on tooth No. 5, and a fracture was evident on tooth No. 3. On the opposite end, teeth Nos. 13 and 14 had been endodontically treated, and recurrent caries were evident.
The patient was a successful businesswoman and wanted her smile to match her accomplishments. Unfortunately, she was also slightly phobic of the dental profession and had neglected her teeth. Initially, the patient only wanted cosmetic work that would enhance her maxillary teeth to the molars as well as some of the lower anteriors. She would compensate for the remaining teeth by masking them with the way she smiled, as she already was accustomed to doing. She was happy to leave her occlusion alone, as she wanted the work to be done as quickly as possible. However, since she did not have any posterior support due to missing teeth, her case required proper treatment planning with an eye to function as well as aesthetics, or the prosthetics would not last.
In general, since the teeth were severely worn and broken down, it would be impossible to use the habitual bite as a template for the new smile. The patient’s present Shim-bashi measurement was only 12.7 mm. According to the width of her central incisor, the Shimbashi measurement should have been around 18.0 mm. It was evident that her bite had collapsed. Without proper occlusal support, she would eventually lose more teeth and/or bone if the disharmony was not corrected. Despite the fact that she wanted the work done as quickly as possible, she finally agreed to restore her mouth functionally when she realized aesthetic work alone may not last because of the occlusal and anatomical imbalances of a traumatic bite.
The patient was first treated with general laser therapy of all gum tissue. By utilizing Laser Assisted New Attachment Procedure (LANAP), there would be little or no loss of gingival tissue, which is an extremely important consideration in a complete smile makeover case. The Periolase MVP-7 is specifically designed around the LANAP technique. This technique destroys bacteria and biofilms on contact while initiating periodontal regeneration. Tooth No. 29, a fractured root canal tooth, was extracted and osseously treated via laser.
Teeth Nos. 13, 14, and 19 were retreated endodontically using both the Waterlase MD Er,Cr:YSGG (BIOLASE) and Periolase MVP-7 Nd:YAG laser; any metal posts were removed and replaced with a nonmetallic one. Teeth Nos. 14 and 30 were built up prior to restoration with ceramic using a CEREC 3 in-office CAD/CAM system (Sirona). All caries were removed using an electric hand-piece and disinfected using the Waterlase MD laser (Note: This laser system is specifically designed for hard tissue). Dental lasers allow for precision, excellent hemostasis, and homeostasis in an environment where antisepsis and bactericidal effects are part of their intrinsic function.
The maxilla was protrusively occluded, and the mandible was retrusively occluded on this patient. However, she was not a genuine class II patient, as the teeth negatively adapted to the general and overall breakdown. Since the patient had both an extreme overbite-overjet without posterior support, the upper anteriors had migrated forward and out, and the lower anteriors had migrated back and in, with the exception of one tooth. The K7 Evaluation System (Myotronics) was instrumental in the analysis and design of this case. Electromyography indicated a lack of muscle activity throughout functional movements due to the flattening and lack of sufficient occlusal surfaces on both arches. Restoratively the patient was returned to a class I occlusion within a short time period.
|Figure 6. Maxillary posterior fixed orthotic with combination anterior interim provisionals.||Figure 7. Restored smile. Very open, natural smile.|
The patient would receive an orthotic device 6 weeks prior to restoration to relax the negative occlusal forces and to achieve a correct vertical dimension while gradually correcting the bite (Figure 6). A comprehensive K7 analysis was performed prior to any orthotic work. Also, the K7 was used during orthotic therapy to ensure that treatment was heading in the right direction. During occlusal adjustments of the orthotic, a Myotronics TENs unit was used to help find and restore the proper muscular resting position, ensuring that the temporal mandibular joints would not be strained in the new vertical dimension of occlusion.
In order to restore this particular patient functionally, all her teeth had to be prepped and crowned. Most patients do not require such extensive work to correct the occlusion. The patient received 2 new Lava (3M ESPE) bridges for teeth Nos. 3 to 5 and teeth Nos. 28 to 30. She also received 18 individual all-ceramic crowns (Softspar [Jeneric/Pentron]). Anteriorly, the vertical dimension of occlusion was increased by a little more than 5.0 mm (Figure 7).
|Figure 8. May 2008, full face.|
This case was successfully treated using a cosmetic-functional approach. When the patient smiled prior to treatment, the lower arch was practically invisible as the upper anteriors blocked its view. Now both arches are clearly visible when smiling due to the increased vertical throughout, giving a lift to the face and smile. As a consequence the smile became brighter and wider, giving full expression to the person behind the smile. Three years after this case was completed, the patient is stable without any signs of deterioration or decrease in the vertical dimension. There also has been no debonding and/or breakage of the restorations or teeth. The TMJ complex is healthy as well (Figure 8).
The patient today is very happy with the aesthetics and function of her full-mouth smile makeover. Ever since she has been able to chew her food properly and smile and laugh without covering up with her hand or lips, she knows what good occlusal health means. Kathy, now in her early 60s, is determined to keep her teeth healthy and beautiful for the next 30 years.
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