Compromised Hard- and Soft-Tissue Architecture: Immediate Implant Placement and Provisionalization in the Esthetic Zone

Daniel D. Gober, DDS; Markus L. Weitz, DDS; and Randi J. Korn, DMD

Immediate implant placement and provisionalization have been shown to have cumulative survival rates comparable with those of implants placed in healed sites.^1-3 Recently, Tarnow et al⁴ demonstrated that for teeth in the esthetic zone, immediate implant placement with a bone graft and contoured provisional crown results in the smallest amount of facial-palatal contour change (less than 1 mm). Careful case selection is crucial to achieving short- and long-term success. Therefore, caution should be exercised for a tooth that presents with a compromised soft- and hard-tissue architecture. In such a case, it may be preferable to select an early or delayed protocol to augment the hard and soft tissue of the site prior to implant placement.^5,6

These nonimmediate protocols, however, present many disadvantages.⁷ The number of surgical visits is increased along with the postoperative recovery time and patient morbidity. Treatment time can be as long as 6 months. In addition, the patient’s provisionalization options are limited to either a fixed bonded restoration, which is difficult to retain in place for an extended period, or an interim removable prosthesis, which is uncomfortable and can impair healing of the surgical site if it applies transmucosal pressure.

By applying the principles elucidated in the current literature, immediate implant placement and provisionalization can even be performed for a tooth in the esthetic zone with existing soft- and hard-tissue deficiencies. The following report describes a case with a severely reduced but healthy periodontium for a tooth planned for extraction. Immediate implant placement and provisionalization with a technique utilizing the extracted tooth with simultaneous hard- and soft-tissue augmentation was performed in one visit. Following 12 weeks of healing, implant osseointegration, soft-tissue augmentation, and emergence profile development were achieved, which ultimately facilitated the delivery of a healthy, functional, and esthetic final restoration.

Case Report

Presentation

A 68-year-old Caucasian woman presented with a chief complaint: “My front tooth has become so loose [that] it feels like it is about to fall out of my mouth” (Figure 1). She had a history of periodontal treatment and had been compliant with a 3-month periodontal maintenance schedule for the past 10 years. Although she had noticed this problem for several years, she no longer had comfortable functioning with the tooth’s current degree of mobility.

Clinical evaluation revealed that tooth No. 9 was extruded and facially positioned. Probing depths measured between 2 mm and 3 mm, with up to 7 mm of recession and no attached keratinized tissue. The tooth demonstrated Miller class 3 mobility with detectable fremitus. Radiographically, severe bone loss was noted near the tooth and only a few millimeters of bone was present from the apex of the tooth to the nasal floor (Figure 2). The adjacent teeth presented with probing depths measuring 2 mm to 3 mm, recession up to 4 mm, and Miller class 1 mobility. Although the patient had a low smile line,⁸ she was unhappy with the marginal gingival discrepancy between her central incisors.

Treatment Planning and Procedure

Despite the dental team’s recommendation to comprehensively examine and treatment plan her whole dentition, she requested to treat only this particular tooth at this time. Treatment options were offered based on whether to maintain or extract the tooth. The patient elected extraction and implant replacement.

A cone-beam computed tomography (CBCT) scan was taken of the area and revealed a thin buccal plate with a crest located 2 mm apical to the palatal bone crest. The nasopalatine canal was identified 4 mm palatal to the palatal socket wall, and approximately 4 mm of bone was apical to the socket below the nasal floor (Figure 3). The patient was informed that, due to the deficient soft and hard tissue, neither immediate implant placement nor immediate provisionalization was guaranteed. A bone graft and soft-tissue graft would be required to augment the hard and soft tissue and coronally position the facial margin. The patient stated that she understood all the findings and consented to the proposed treatment plan.

As the dental team had instructed, the patient premedicated with 2 g amoxicillin and 600 mg ibuprofen 1 hour prior to the procedure. Following administration of local anesthesia, atraumatic extraction was performed by severing the remaining soft-tissue attachment with a periotome and delivering the tooth with extraction forceps. The socket was debrided with a surgical curette and irrigated with a saline solution. Careful exploration of the socket with a periodontal probe revealed that the remaining buccal plate was intact with no fenestration or dehiscence and its crest was located approximately 3 mm from the free gingival margin.

Using a precision drill, the implant osteotomy was initiated at the junction of the mesial and palatal walls. Twist drills were used to progressively enlarge and widen the osteotomy as per the manufacturer’s recommendations. Attention was given to ensure the osteotomy remained along the palatal wall so that a horizontal dimension would remain between the buccal surface of the implant and buccal plate. A finger was placed on the facial tissue during site preparation so that any inadvertent perforation of the buccal plate would be detected. The angulation of the drill within the osteotomy was constantly checked to assure that the access would exit just palatal to the future incisal edge to accommodate a screw-retained option. In addition, before continuing with each successive drill, sufficient resistance to movement of the drill within the osteotomy was confirmed.

Following osteotomy preparation, a 4.2-mm x 10-mm Touareg™ S implant fixture (Adin Dental Implant Systems, adin-implants.com) was placed with more than 35 Ncm of torque. The head of the implant was placed slightly below the palatal crest and level with the buccal alveolar crest. The implant body was in contact with the mesial and palatal walls but was exposed to the socket space on the distal and facial (Figure 4). A periapical radiograph was taken and suggested that the nasal floor may have been perforated during implant placement (Figure 5). A CBCT scan was taken to confirm the position of the implant within the socket relative to the nasal floor (Figure 6). A slight perforation was noted but determined to be of no consequence, and the implant was left in its current position.⁹

Following implant placement, a subepithelial connective tissue graft was harvested from the right palate using a single-incision palatal harvest technique and tucked into a facial pouch, which was elevated without surface incisions to augment the soft-tissue volume at the site.¹⁰ Deproteinized bovine-bone mineral particulate graft (Bio-Oss™, Geistlich Pharma North America, Inc., geistlich-na.com) was placed in the horizontal defect dimension and the remaining socket space to preserve the ridge dimension and minimize buccal plate resorption. Because a slight tension on the facial tissue was observed, a surface vestibular incision was made down to the periosteum to relieve any tension and allow for passive adaptation of the soft-tissue margin. (Figure 7)

Following hard- and soft-tissue grafting around the implant, immediate provisionalization commenced utilizing an extracted-tooth provisional-crown (ETPC) technique. A prefabricated hexagonal temporary metal abutment was secured to the implant by hand and a component prefabricated polymethylmethacrylate (PMMA) sleeve was placed over the abutment (Figure 8). The extracted tooth was cut horizontally with a carbide bur 2 mm apical to the clinical cemento-enamel junction separating the crown from the root. The crown portion was hollowed out, and the inside was etched with phosphoric acid. The ETPC was filled with acrylic, seated onto the abutment, and allowed to set for 5 minutes, facilitating the “pickup” of the PMMA sleeve within the ETPC. Once set, the ETPC was removed along with the PMMA sleeve inside it, leaving the abutment in place.

The ETPC was placed on an abutment replica, and acrylic was added to the subgingival portion to create an emergence profile that was circular at the subcritical level and slightly concave at the critical level, which would allow for coronal positioning of the soft-tissue margin¹¹ (Figure 9). The subgingival portion of the ETPC was smoothed and polished to promote adhesion of the peri-implant tissue.¹² The ETPC was tried back on to the abutment, and the occlusion was adjusted until all centric, excursive, and protrusive contacts were eliminated.

To avoid excess cement from extruding subgingivally, the abutment analog was also used to aid in the cementation. The ETPC was loaded with zinc oxide non-eugenol cement (TempBond® NE, Kerr Dental, kerrdental.com) and completely seated onto the abutment analog to express excess cement and ensure only a thin uniform layer of cement lined the inside of the PMMA sleeve. The ETPC was removed from the analog and placed onto the temporary implant abutment and allowed to set. A radiograph was also taken to confirm that no excess cement was present. A mattress suture was used to coronally advance and stabilize the facial soft-tissue margin against the ETPC (Figure 10). The patient was given a prescription of amoxicillin 500 mg three times a day for 7 days and diflusinal 500 mg twice a day for the first 3 days postoperatively and was instructed to avoid biting with the ETPC.

The patient reported minimal postoperative swelling and discomfort at the implant site. At the 1-week postoperative visit, the site was healing within normal limits. No signs of delayed healing or infection were present. Slight edema of the tissue margin consistent with 1 week of healing of a connective tissue graft was observed. The patient was instructed to continue to avoid biting with the tooth and to keep the area plaque free by locally applying chlorhexidine 0.12%.

After 3 months, the patient returned for evaluation of implant osseointegration and soft-tissue healing. The ETPC and temporary abutment were removed, and secondary stability of the implant was confirmed with a reverse-torque test up to 20 Ncm.¹³ The peri-implant soft tissue had stabilized coronally and was now even with the adjacent central incisor (Figure 11). The soft-tissue profile appeared thicker, with an increase in attached keratinized tissue. A periapical radiograph demonstrated bone healing around the implant and bone fill of the socket spaces (Figure 12). An occlusal view of the peri-implant tissue showed the ridge contour had been reestablished and an anatomic emergence profile had developed around the ETPC (Figure 13). The patient returned to her restorative dentist for the final abutment and crown fabrication. A cement-retained porcelain-fused-to-metal implant-supported crown was fabricated, and the incisal edges of the other maxillary teeth were recontoured to improve esthetics (Figure 14). Bone and soft-tissue levels remained stable after 1.5 years and probing depths around the implant were limited to 1 mm to 2 mm with no bleeding on probing (Figure 15). The patient was satisfied with the final result.

Discussion

Previous authors have helped to define a predictable surgical and prosthetic protocol for anterior single-tooth immediate implant placement and provisionalization loading in cases with a normal periodontium and a completely intact residual buccal plate of bone.^1,4,14-19 According to previous classification of extraction sockets, immediate placement should be considered only in a type 1 or type A extraction site. Otherwise, an early or delayed approach is recommended.^5,6 Buser et al²⁰ described an early approach in which the socket is left to heal for 4 to 6 weeks to gain gingival coverage of the socket and have more soft tissue for further bone augmentation. A delayed approach would include bone grafting and implant placement following 3 to 6 months of healing.¹ Orthodontic extrusion could also be employed to coronally position the hard and soft tissue of the site prior to implant placement.⁶ All these approaches require multiple surgical visits, additional treatment time, and inconvenient provisionalization options.

Proper implant positioning relative to the socket is dependent on multiple factors. Slight palatal placement of the implant within the socket leaving a horizontal defect dimension or “gap distance” is recommended to compensate for some horizontal ridge resorption that can occur. This is also to ensure proper buccolingual implant positioning and avoid future exposure of implant threads. Slight palatal placement of the implant requires careful preparation along the palatal wall in an apical direction to prevent perforation of the buccal wall with the apex of the implant.^{4,14,18,19-21}

Whether the placement of a graft material into the horizontal defect dimension is necessary remains the subject of study. Wang et al²² demonstrated that as much as 80% of maxillary anterior teeth was present with a facial plate of bone less than 1 mm. This suggests post-extraction resorption is more likely in this region because the facial plate loses half of its blood supply when the periodontal ligament is severed with extraction.²³ Most authors recommend the placement of a graft material into the buccal defect dimension as a means of limiting post-extraction remodeling and resorption of the buccal bone.^14,17,24 Success has been achieved even without the placement of a graft material.²⁵ In addition, the placement of a connective tissue graft with a tunnel technique at the time of placement has been shown to augment the facial soft-tissue profile and is recommended to reduce any changes in soft-tissue contour following immediate implant placement.¹⁶ In this case, deproteinized bovine-bone mineral particulate was used to fill the horizontal defect dimension and remaining socket spaces around the implant. A connective tissue graft was used successfully to augment the facial soft-tissue volume and contour and to increase the zone of attached keratinized tissue.

When immediate implant placement and provisionalization is planned, primary stability of at least 35 Ncm must be achieved so that movement of the implant is avoided during osseointegration.¹ When ample bone height and width is available around an extraction socket, a longer or wider implant can be used to attain high insertion torque. In the case described above, limited bone height precluded an implant length greater than 10 mm. A wide-body implant was not selected because it would have forced the facial surface of the implant to be placed outside the parameters of the alveolar housing possibly resulting in exposure of the facial threads of the implant following healing.¹⁴ Despite these limitations, adequate insertion torque was achieved with a 4.2-mm x 10-mm implant due to the choice of implant used. The implant was selected based on its design, which facilitates increased insertion torque. It is designed with wide self-cutting threads of varying pitch around a tapered core on which the threads become increasingly wider toward the apex of the implant. This enhances the degree of bone compression during implant insertion and increases the amount of primary stability.²⁶ Immediate provisionalization of the implant was completed with confidence, commensurate with the noted stability and insertion torque.

The benefits of immediate provisionalization include more than just the convenience of a fixed interim restoration. The placement of a provisional restoration or an anatomic healing abutment has been shown to preserve anatomic emergence profile and prevent recession of the facial gingival margin.⁴ Reusing the natural tooth as the provisional can help to create a soft-tissue profile that approximates the contours found around natural teeth.²⁷ The contour of the emergence profile of the provisional plays a key role in the maintenance of the soft-tissue architecture depending on the position of the implant.²⁸ When soft-tissue augmentation is desired or the implant is placed in a labial position, an emergence profile that is concave is recommended to allow room for more tissue volume. When excess tissue is present or if the implant head is placed too palatal, an emergence profile that is convex is recommended to push the soft tissue labially and prevent the margin from lying too coronally.²⁸ When preservation of the existing architecture is desired, the anatomic contour is recommended as a means of supporting and stabilizing the soft-tissue margin. In the case described above, the subcritical contour was designed to be circular to replicate the cross-section of the tooth at that level. The critical contour was slightly concave to encourage an increase in the soft-tissue volume and coronal positioning of the gingival margin. This successfully facilitated reestablishment of the ridge contour and maintenance of an emergence profile so that an esthetically pleasing and hygienic final restoration could be delivered.

When cementing a cement-retained implant restoration, the choice of cement and the cementation technique employed are of critical importance to peri-implant tissue health. A cement that is radiopaque should be used so that any excess can be visualized radiographically and removed if necessary. The cement should also be able to reduce planktonic or biofilm growth of the oral pathogenic bacteria to minimize the chances of developing peri-implant disease. A eugenol-free zinc oxide cement has been shown to meet these criteria.^29,30 In addition, a cementation technique designed to minimize the amount of excess cement extruding while seating the crown was employed to prevent the possibility of a foreign-body reaction and ultimately sacrifice peri-implant tissue health.³¹

Conclusion

Within the limitations of a case report, the present article demonstrates that immediate implant placement and provisionalization can be employed successfully even in a compromised situation. By applying the principles illustrated in the existing body of literature, clinicians can offer patients the option of immediate placement and provisionalization in situations that may have been avoided previously. Instead of being forced to resort to protocols that include an increased number of surgical visits, longer healing time, and increased patient morbidity, patients can benefit from the gratification of immediate placement and provisionalization and still receive an esthetic and functional implant-supported restoration.

ABOUT THE AUTHORS

Daniel D. Gober, DDS
Private Practice, Cedarhurst, New York

Markus L. Weitz, DDS
Private Practice, Cedarhurst, New York

Randi J. Korn, DMD
Private Practice, Plantation, Florida

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