Part of a new series in collaboration with AACD
Charting the Course of Success
A systematic, interdisciplinary approach planning for the loss of a hopeless maxillary central incisor
Achieving esthetic excellence in anterior dentition often requires restorative dentists to use an interdisciplinary approach in planning treatment for difficult cases. To ensure health, beauty, and function for patients with failing anterior teeth and high smile lines, it is incumbent upon restorative dentists to share their vision of desired treatment outcomes with the patient, specialists (eg, periodontist, orthodontist), and laboratory technician.
Over the past few decades, some patients have developed a heightened awareness of dental esthetics and are more adamant about wanting “to look better” than previous generations. For some of these patients with complex challenges (eg, compromised soft tissue, papilla and bone volume loss, space issues), the amount and length of treatments can be daunting. However, the ultimate results can be well worth it.
Spear and colleagues advocate beginning treatment planning with esthetics and proceeding to function, structure, and biology.1 According to this concept, if esthetics are not considered first, final outcomes may be compromised. Many other factors—eg, smile line, tooth proportions, tooth display—are also significant.2 Additionally, when planning to transform a patient’s smile, considering the gingival architecture that will “frame” the restorative treatment is important.
This article describes a well-planned, systematic, and interdisciplinary approach to “reverse-engineering” the treatment plan from goal to beginning, which enabled the team to achieve an excellent esthetic outcome.
Case Presentation
A 49-year-old woman reported a history of facial trauma resulting in a fracture and intrusion of tooth No. 8. She underwent orthodontic treatment as a child, but failed to use retention and ultimately continued to relapse. She experienced ongoing periodontal and occlusal disease and was treated intermittently by a periodontist and her general dentist. In 2009, she determined that her smile was becoming increasingly unattractive. There were black triangles between her teeth, and tooth No. 8 was mobile and had drifted facially (Figure 1 and Figure 2). Her goal was to minimize the number of teeth she would lose to periodontal disease and have “a pretty smile.”
Diagnosis and Treatment Planning
The patient understood she had bone and papilla loss. Adjunctive orthognathic surgery to address the mandibular retrognathia, convex soft tissue profile, and recessive chin were discussed but declined. Based on facially generated treatment planning, the following diagnostic sequence was used to develop a treatment plan: gather data during the examination (eg, history, temporomandibular joints [TMJs], muscles, dental, periodontal, photography); identify the current condition and desired outcome; and choose the treatment method.
To begin treatment planning with esthetics, starting with an appraisal of the maxillary central incisor relative to the upper lip has been advocated. Evaluating the incisal edge position of the maxillary central incisor relative to the upper lip at rest enables restorative dentists to determine what is acceptable. The average 30-year-old shows 3.3 mm of central incisor at rest.3 Using that criteria, the incisal edge display for this patient at rest was deemed adequate.
The next step to determine the esthetic relationship of maxillary anterior teeth is evaluating gingival levels. This patient presented a gummy smile and anterior teeth that were too short. She had a black triangle and gingival asymmetry between teeth Nos. 8 and 9. The gingival margins had to be moved apically after extruding No. 8 to bring down the bone and tissue.
The final three criteria for evaluation are tooth alignment and position, contour (proportion and outline form), and color. In this case, tooth position, gingival levels, and alignment were unacceptable, complicating treatment and involving the occlusion due to excessive display of the mandibular anterior teeth. The Curve of Spee also required leveling. To finalize the desired tooth arrangement, a diagnostic wax-up incorporating the patient’s specific tooth shape requests would be made.
To integrate the planned esthetic changes with this patient’s functioning occlusion, the TMJs and muscles were first evaluated. A nocturnal bruxism habit was reported and enamel wear was evident, but no significant temporomandibular disease symptoms were found.
Once esthetics and function were evaluated, tooth structure was examined. Anterior tooth proportions were unacceptable. Tooth biology was evaluated to facilitate biologic treatment planning and establish health between the teeth and tissue in the desired location. After referral to the periodontist, it was determined that tooth No. 8 was non-maintainable due to severe periodontal disease—formation of a chronic abscess. Additionally, maxillary molars were periodontally compromised and required treatment.
Therefore, the end goals of treatment included preserving tooth display at rest; maintaining the lower lip-to-incisal edge relationship (with the exception of tooth No. 8, which would be brought coronally into the incisal plane); preserving the occlusal plane in the maxillary arch; raising the gingival levels of all maxillary teeth except No. 8, which would be extruded; intruding the mandibular anterior sextant and leveling the mandibular occlusal plane; and controlling/eliminating periodontal disease. The following treatment sequence was formulated to accomplish these goals:
1. Scaling and root planing for initial periodontal therapy.
2. Comprehensive orthodontic treatment to intrude the lower incisors and “open” the deep overbite; extrude No. 8 to bring bone and soft tissue (papilla) coronally to improve future implant placement success and overall esthetic outcome; adjust the mesial-distal width of the No. 8 space to its correct proportional dimension; and coordinate occlusion for future prosthetic treatment (Figure 3 and Figure 4), including positioning of the gingival architecture of teeth Nos. 6 through 11.4-9
3. Microsurgical crown lengthening of teeth Nos. 4 through 13, with the exception of tooth No. 8, which would remain untouched (Figure 5).
4. Microsurgical immediate extraction, implant placement, bone graft, connective tissue graft, and fabrication of a screw-retained, custom provisional, in accordance with the SMILE Technique described by Shanelec and Tibbetts.10,11 This technique consisted of 36 sequential and distinct steps designed to produce excellent immediate esthetics and patient acceptance,11 and a final restoration fabricated by replicating the provisional emergence profile achieved during the immediate microsurgery.
Treatment Phase
Performing this critical treatment phase under high magnification, using a surgical microscope and following a methodical series of microsurgical and micro-restorative steps provided several advantages. These included a precise surgical procedure and enhanced motor skills; application of microsurgical instruments to reduce tissue trauma, resulting in little to no prolonged bleeding; excellent surgical field illumination; and precise implant site preparation. Also advantageous was exactly fabricating a highly polished, anatomically correct provisional with the implant platform precisely located at ≤ 5 mm below the crest of the papilla, thus consistently maintaining mesial and distal papilla height and reducing soft tissue irritation, as was emphasizing passive wound closure with exact primary apposition of wound edges.12 Additionally, these steps enabled transfer of the provisional subgingival contours onto a custom impression transfer coping, facilitating accurate communication with the laboratory technician for exact reproduction to the final digitally scanned custom zirconia abutment and crown.
Further, this process enabled fabrication of a custom impression coping and custom zirconia abutment to reflect the ideal subgingival profiles obtained with the SMILE provisional and final restorative treatment. Prior to the crown-lengthening surgery, the restorative dentist created study models for fabricating a wax-up to best communicate the desired length of the final restorations to the periodontist. The patient was also sent for digital imaging (Smileography™, smileography.net) of the desired final restoration proportions on a photograph of her face.
Two months after surgical implant placement (Branemark Mark IV, regular platform 4 x 18 mm implant, Nobel Biocare®, www.nobelbiocare.com) and abutment and crown provisionalization (Figure 6 through Figure 9), the patient was provided with custom whitening trays and 10% bleaching gel (Opalescence®, Ultradent Products, Inc., www.ultradent.com) to enhance the natural tooth color (Figure 10). She bleached for approximately 1 month.
Three months after implant placement, a fixture-level impression was taken using the custom impression coping fabricated from the silicone impression made of the subgingival profile of the SMILE provisional, which was taken at the time of surgery. A custom zirconia abutment and crown were then fabricated.
The temporary bridge spanning teeth Nos. 7 through 10 was sectioned. Once a temporary restoration is removed from around an implant, gingival tissues tend to collapse quickly over the implant platform. To capture the molded soft tissue and emergence profile developed with the provisional, a custom impression coping is used to resolve this problem. This was accomplished by screwing the implant provisional onto an implant analog and capturing the cervical portion of the provisional with a clear polyvinyl siloxane impression material. The subgingival impression created by the provisional crown was filled with a clear, flowable light-curing composite to transfer the soft-tissue emergence profile to the impression coping. A final impression using this customized impression coping was taken and sent to the laboratory for fabricating the zirconium abutment and provisional.
The laboratory fabricated a soft-tissue cast model duplicating the contours captured in the custom impression coping technique. The custom impression coping was scanned (Procera® scanner, Nobel Biocare) to create a custom zirconia abutment mimicking the contralateral central preparation. Care was taken to place the margins 0.5 mm subgingivally for easy cement removal, and a custom temporary was made to fit precisely to the abutment.
Once the zirconium abutment and new custom implant provisional were placed, the patient returned 2 weeks later to refine the margins of teeth Nos. 7, 9, and 10. An impression was taken of these teeth to create a strong and durable long-term laboratory-processed provisional.
The final restorations were fabricated 4 months later, the remaining teeth—Nos. 5, 6, 11, and 12—were prepared for veneers (Figure 11), and an impression was taken. The implant abutment remained in the mouth as a tooth preparation.
Model work was completed, and the technician selected lithium disilicate (IPS e.max®, Ivoclar Vivadent, www.ivoclarvivadent.com) for the final restorations. The temporary model was copied with laboratory silicone and used to inject wax over the prepared model. Because the patient desired a brighter smile, the technician used shade LTBL3.
The restorations were pressed, cut back, and stained in the incisal zone. This stain was fired at a low temperature, and a combination of incisal 2, opal 2, clear, and translucent incisal was overlaid on the internal stain. The restorations were contoured and textured with an assortment of diamonds (Komet USA, www.kometusa.com), then glazed, polished, and etched for delivery. The final restorations were cemented (Insure Clear Resin Cement, Cosmedent, www.cosmedent.com) (Figure 12), and a night guard was fabricated.
Discussion
A chief concern in this case was the hard and soft tissue deficiency in the esthetic zone, so one major interdisciplinary goal was regaining the balance and harmony of this patient’s smile, especially considering the loss of the hopeless maxillary central. To maintain gingival harmony, pre-extraction orthodontic extrusion of tooth No. 8 was planned. Slow orthodontic extrusion of a single tooth is utilized to re-establish the integrity of an alveolar ridge via increased bone volume for future implant placement. By controlling the orthodontic treatment phase, hard and soft tissues can be manipulated into a position that permits an esthetic restoration.
Moving a tooth by extrusion involves applying tractional forces in all periodontal ligament regions to stimulate marginal apposition of crestal bone. Because gingival tissue is attached to roots by connective tissue, the gingiva follows vertical movement of the root during the extrusion process. Similarly, the alveolus is attached to periodontal ligament roots and is, in turn, pulled along by root movement.
Extrusion is the easiest orthodontic movement because it closely resembles natural tooth eruption. Orthodontic extrusion forces coronal migration of the root and increases the bone ridge and quantity of attached gingiva, particularly when weak-to-moderate forces are applied. Note that when a single tooth implant is placed adjacent to natural teeth, the interproximal papilla levels are determined by the height of the interproximal bone on the adjacent natural teeth, not the interproximal bone on the implant.
Managing the soft tissue surrounding the implant can be challenging and complex. Microsurgery represents a movement toward minimally invasive dentistry. In this case, the periodontist used Shanelec’s technique of placing an immediate implant in the extraction socket under the microscope to reduce trauma, along with an immediately placed, screw-retained, highly polished, anatomically exact provisional to shape the tissue surrounding the implant. This provisional was important for shaping the peri-implant tissue to restore and enhance gingival esthetics. By shaping the provisional crown to closely duplicate the contours of the desired final restoration, an exceptional esthetic result could be achieved (Figure 13).
Conclusion
Despite the added time and expense, orthodontic extrusion remains a beneficial technique for patients with a high lip line and hopeless maxillary anterior teeth. In this case, orthodontic treatment consisted of 10 months of extrusion, with intermittent periods of retention. It was also critical for the interdisciplinary team and patient to be clear about treatment goals and what could be realistically achieved. This allowed the patient to make informed decisions about the desired outcomes and the financial and time commitments required for treatment plan completion. When planned correctly, highly challenging cases can produce very esthetic solutions for patients and rewarding experiences for teams.
About the Authors
Marilyn Calvo, DDS, AAACD
Smile Studio LA
Encino, California
Rick Alter, DDS
Buto and Alter Orthodontics
Oxnard, California
Adriana McGregor, DDS
Private Practice
Westlake Village, California
Erik Haupt, BA, AAACD
Haupt Dental Lab
Brea, California
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