Single Maxillary Anterior Tooth Restoration

Case to replace a non-restorable maxillary left canine illustrates a team approach.

Steven Present, DMD; Robert A. Levine, DDS

The loss of a tooth in the esthetic zone has a profound effect not only on the patient’s appearance, but also on function and speech. To quote the late Dr. Leonard Abrams, “There is a direct relationship between a person’s physical beauty and self esteem.” Therefore, the goal of successful esthetic implant therapy not only involves the replacement of the missing tooth, but also to restore the osseous contours and the gingival envelope to mimic the contralateral tooth as it emerges into the oral cavity through the transmucosal region. According to ITI Treatment Guide Consensus Statement C.¹ Standards for an Esthetic Fixed Implant Restoration: “An esthetic implant prosthesis was defined as one that is in harmony with the peri-oral facial tissues of the patient. The esthetic peri-implant tissues including health, height, volume, color, and contours, must be in harmony with the healthy surrounding dentition. The restoration should imitate the natural appearance of the missing dental unit(s) in color, form, texture, size and optical properties.”^1-5To best accomplish this and to better serve our patients, a team approach using the specialized talents and expertise of many individuals is required, all working together for a common goal. Generally, the restorative dentist formulates the preliminary treatment plan with sequencing. Other team members (periodontist, oral surgeon, orthodontist, endodontist, laboratory technicians, etc.) will add and revise. Then the final treatment plan is formulated and presented to the patient for approval. The following case to replace a nonrestorable maxillary left canine illustrates this team approach.^6,7

A 57-year-old woman presented for replacement of the upper left canine (tooth No. 11) with a dental implant. The tooth previously had root canal therapy but had fractured and was nonrestorable. As a result, the tooth was extracted in 2006. Her medical history was unremarkable. Clinical examination revealed missing teeth Nos. 1, 4, 5, 11, 15, 16, 19, and 30. There was a Class 1 occlusion with normal overjet and overbite. However, she had a left crossbite from teeth Nos. 10 through 14, a crossbite between teeth Nos. 7 and 27, and the lower molars had drifted mesially into the edentulous spaces from teeth Nos. 19 and 30. Tooth No. 12 previously had root canal therapy but was not restored with a crown.

The treatment plan consisted of:

• Orthodontic therapy.
• Periodontal evaluation with appropriate nonsurgical therapy.
• Implant surgical placement in tooth No. 11.
• Implant screw-retained provisional restoration to help in tissue “sculpting.”
• Completion of final crown on tooth No. 11, 3 months after provisionalization.
• Completion of tooth No. 12 crown.
• Future implant placement and restorations of teeth Nos. 19 and 30.
• Periodontal maintenance phase alternating between offices.

The patient did not want to wear a fixed orthodontic appliance. Invisalign^® (Align Technologies, https://www.invisalign.com) was chosen to provide the necessary correction. Treatment began with a series of 29 aligners. The appliances made the correction of the crossbite easier as the teeth were disarticulated during the entire process. A pontic was fabricated to fit in the space of tooth No. 11 as it was extracted before treatment. This satisfied the patient’s esthetic demands during treatment. After the initial set of trays, a refinement was required involving 10 additional aligners.

Presentation to the Periodontist’s Office

The patient presented upon referral from the restorative office for evaluation of site No. 11 for a single implant (Figure 1, Figure 2, Figure 3). As noted, her medical history was uneventful and there were no contraindications to surgical therapy. She was very compliant to her periodontal maintenance schedule with her previous general dentist, was a nonsmoker and did not admit to any parafuctional habits. Periodontal and occlusal examinations revealed posterior areas of 4 mm to 5 mm probing depths with bleeding upon probing. Teeth Nos. 19 and 30 were missing and future implants were discussed for these edentulous areas. The Angle classification was a Class 1 occlusion with 2-mm overbite and overjet. No significant mobilities were recorded. Site evaluation of tooth No. 11 revealed a moderate buccal concavity/ridge defect resulting from the natural loss of the facial hard tissue postextraction, which can be anticipated when a ridge preservation technique is not completed at the time of extraction.^8-12 An Implant Esthetic Risk Profile¹ was reviewed with the patient and a medium esthetic risk was determined. The following “finalized” team treatment plan was developed:

1. Nonsurgical periodontal therapy consisting of scaling/root planing with subgingival antibiotic placement in conjunction with 20-mg doxycycline therapy to help in healing soft and hard tissues with reduction of bleeding upon probing. This patient’s main periodontal risk factor for future implant loss would be her present periodontal disease if left untreated. In addition, the concerns with periodontal inflammation and its systemic health risks were also reviewed with the patient. The treatment and reduction of her pathologic periodontal pockets with generalized bleeding upon probing (inflammation) had systemic health benefits as well. The multipronged approach that was presented to the patient has been used successfully in the authors’ office for more than 10 years as part of phase 1 periodontal therapy.¹³
2. Anatomically correct surgical guide template fabricated by the restorative dentist to aid in 3-dimensional placement of the implant (Figure 4).^3,14
3. Implant surgical placement with evaluation for bone regenerative and reconstructive therapy (bone graft with membrane). When placing dental implants (especially in the esthetic zone) the treating “surgeon” needs to think and treat like a periodontal plastic surgeon. It requires wide knowledge of all phases of periodontal plastic surgery, ie, connective tissue grafting, reconstructive bone grafting surgery (guided bone regeneration/guided tissue regeneration), “gummy smile” correction, orthodontic extrusion/forced eruption, and osseous surgery since most esthetic zone cases require at least one or more of these procedures for a successful esthetic outcome.^9-16 Treating in the esthetic zone is an “advanced” or “complex” procedure according to the SAC Classification and should never be looked at as a “routine” or simple procedure.^17-22
4. Provisionalization of site No. 11 with timing based on initial torque values and need for guided bone regeneration/reconstructive soft and hard tissue surgery at the time of placement. The screw-retained provisional will act as the “blueprint” for the final crown. The patient would be wearing the provisional for at least 3 months.^2,4,9,23,24
5. Completion of the final crown on tooth No. 11 using a CAD/CAM fabricated zirconia abutment.
6. Periodontal maintenance every 3 months alternating between offices with future discussions for tooth replacement for site Nos. 19 and 30 with dental implants.²⁵

Implant Surgical Phase

The patient was treated using local anesthesia and was premedicated with a nonsteroidal anti-inflammatory drug, an antibiotic (amoxicillin) and a surgical rinse of CHG 0.12%. Incisions included a mid-crestal with mesial and distal vertical releasing which aided in reflection with a goal of papillary sparing so as to help prevent any postoperative recession of the adjacent natural teeth. The surgical guide template was positioned and used throughout the procedure to judge proper positioning of the implant in three dimensions. For tissue-level implants, a 2-mm to 3-mm distance is recommended from the mid-buccal of the guide template as is a 3-mm to 4-mm distance with a bone-level implant. The co-author (Levine) desires a 4-mm distance for bone-level implants which was used in this case. To create this necessary distance for an emergence profile of 4 mm, osseous crest reduction was required and was performed by scalloping the ridge with a high-speed round bur under copious sterile saline irrigation (Figure 5).

The oral plastic surgeon needs to look closely at the site once the implant is properly positioned with the aid of the surgical guide. The desire was also to re-create what the patient had lost in soft and hard tissue contours and to try to create symmetry with the contralateral tooth No. 6. Considering that there was no deficiency in the amount and thickness of attached keratinized gingiva at presentation for site No. 11, the surgeon needed to then determine based on the osseous present to the facial and/or lingual whether a soft or hard tissue graft or both are necessary. This decision is usually made after the implant has been placed or by evaluation of presurgical CT scans of the site.

The co-author, as part of the discussions with the patient preoperatively, routinely reviews the possibility of either or both procedures needed after implant placement and reevaluation of the site. The palatal soft tissue is routinely anesthetized on the same side of all esthetic zone implant procedures in anticipation of using the thick premolar palatal tissues as a donor site for connective tissue grafting. The desired osseous thickness was noted to be less than 0.5 mm on the facial and a bone graft was decided to be the choice of reconstructive surgery for the site. A slowly resorbing anorganic bone graft was mixed with sterile calcium sulphate powder (4:1 ratio) and was covered with a customized resorbable collagen membrane to aid in membrane-protected guided bone regeneration (Figure 6, Figure 7, Figure 8). The area was sutured with fine periodontal plastic surgical resorbable sutures (6-0 vicryl) which aids in excellent approximation of the vertical releasing incisions to help reduce the incidence of postoperative scarring of the incision lines. The surgeon needs to avoid any large diameter sutures (4-0, 3-0) in especially the vertical incision lines to prevent any unwanted scarring and trauma to the flap with its compromise of its blood supply. An undercontoured 6-mm bottleneck healing abutment was placed to prevent any pressure on the buccal flap. The bottleneck healing abutment also helps in primary closure of the vertical releasing incisions and easy access to the top of the implant (Figure 9). The patient went home after postoperative instructions were reviewed wearing her last Invisalign tray after adjusting the undersurface acrylic on tooth No. 11 to allow space for the soft tissues and the healing abutment (Figure 10).

At the 3-month postoperative appointment, the bottleneck healing abutment was removed, bone healing was tested without anesthesia with a reverse torque test of 35 Ncm using a RC implant carrier device and the manufacturer’s (Straumann) torque driver taking the torque slowly up to the 35 Ncm line and then reversed and removed. If the patient does not feel any discomfort or movement of the implant is not felt or viewed clinically the case is ready for prosthetic completion. Finally at this visit, topical anesthetic is placed into the site for 1 to 2 minutes and a 6X6 mm conical healing abutment is placed slowly to depth to “stretch” the tissues. Blanching of the soft tissues will usually occur and disappear in a couple of minutes (Figure 11). The patient had a previously coordinated appointment with her restorative dentist (Present) for provisionalization of the implant.

Prosthetic Phase

The development and appearance of the transmucosal region as the tooth emerges into the oral cavity can be the difference between treatment failure and success. It is important to use the provisional to sculpt the peri-coronal tissue to duplicate to the best of our abilities the contralateral canine. According to the ITI 3^rd Consensus Conference: “to optimize the esthetic outcomes, the use of provisional restorations with adequate emergence profiles is recommended to guide and shape the peri-implant tissue before definitive restoration.”^1,3,4 A primary goal in the development of the soft tissue contours is to have predictability and long-term stability. To achieve this we must give adequate time for maturation of the soft tissue prior to making our final impression.

Immediately after second-stage surgery, a screw-retained provisional was fabricated using a Straumann RC Temporary Meso Abutment (Figure 12 and Figure 13). A screw-retained provisional was used because it could be easily removed and the contours modified as the emergence profile was developed. In addition, there would be no danger of leaving residual subgingival cement which can significantly compromise wound healing. Finally, the provisional could be used to fabricate a custom impression coping. The provisional would be evaluated every 3 to 4 weeks for the next 3 months to evaluate the tissue contours, modify the provisional as needed, and to allow adequate time for the maturation of the soft tissue. At 4 weeks the provisional was evaluated and the contours modified to improve the pericoronal architecture (Figure 14). The patient returned again at 8 weeks and a small fistula was present near the apex of the implant. The implant was stable with no radiographic bone loss. It was determined that the fistula was likely originating from tooth No. 12, which had a previously treated root canal. The fistula was followed with a gutta-percha point, which approximated the apices of No. 12. She was referred for endodontic evaluation and re-treatment. After re-treatment, the fistula closed and the area healed uneventfully. The endodontist recommended 6 months before a definitive restoration was fabricated for No. 12. At 3 months the peri-coronal tissue was mature, the desired emergence profile had been established, and the patient was ready for the impression for the master cast.

To prevent the collapse of the peri-coronal tissue and accurately transfer the developed emergence profile established by our provisional restoration to the working model and communicate the clinical situation to the laboratory technician, a custom impression coping must be used. The technique to make a custom impression coping includes:

1. The provisional crown with the established emergence profile is removed from the mouth and the appropriate implant analog is attached.
2. The crown-analog structure is imbedded into PVS impression putty and wash to the depth of the cervical third of the clinical crown. The facial surface of the crown is marked on the impression putty (Figure 15).
3. Remove the provisional crown by unscrewing, leaving the analog embedded in the impression putty.
4. Attach an open-tray impression coping to the implant analog (Figure 16).
5. Apply pattern resin to the impression coping, filling the space completely (Figure 17).
6. Mark the facial aspect on the impression coping, remove, trim any flash, position the coping, and make the impression (Figure 18 and Figure 19).

After the impression, bite registration, and color mapping, the impression was sent to the laboratory for fabrication of an Ekton^® zirconium custom abutment, coping, and crown. The abutment was delivered torqued to 35 Ncm as per Straumann recommendations, and the screw access was sealed (Figure 24). The crown was cemented with Premier^® Implant Cement™ (Premier Dental Products, https://www.premusa.com) (Figure 20, Figure 21, Figure 22, Figure 23, Figure 24).

Conclusion

Osseointegration today has progressed to a point where it is taken for granted and the focus has shifted to esthetics. Patients not only expect a functional long-term restoration, but also one that is esthetic, gives the illusion of the missing dental units, and is in harmony with the peri-implant tissues. To better serve our patients and to optimize treatment outcomes, a team approach should be used where the talents and expertise of various specialists are used.^26-28

Acknowledgment

The authors would like to thank Paula Chernoff for her editing of the manuscript prior to publication.

Disclosure

Both Dr. Present and Dr. Levine are Fellows of The International Team for Implantology (ITI, Basel, Switzerland); both authors have received honoraria from Straumann and Dr. Levine also has received honoraria from Exactech and PiezoSurgery.

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About the Authors

Robert A. Levine, DDS
Private Practice
Pennsylvania Center for Dental Implants and Periodontics
Philadelphia, Pennsylvania

Clinical Professor of Periodontics and Implantology
Kornberg School of Dentistry
Temple University
Philadelphia, Pennsylvania

Clinical Associate Professor
Post-Graduate Periodontics, Perio-Prosthesis, and Implantology
University of Pennsylvania School of Dental Medicine
Philadelphia, Pennsylvania