Note: The Hahn Tapered Implant System is now known as the Glidewell HT Implant System

Dental practitioners will inevitably encounter patients who have received previous endodontic treatment that is failing. Success rates for endodontic treatment have been reported at 77.8 percent after two years, 71.8 percent after four years, and 62.9 percent after six years.¹ In cases of failed root canal treatment accompanied by a periapical lesion, reported success rates for further endodontic therapy have ranged from 27.8 to 80 percent.^2,3 In many of these cases, depending on the lesion size and the reason for failure, the best treatment option is to extract the tooth and replace it with an implant.

In this case study, there was clinical presentation of a short root, a large endodontic post, Class I mobility and a large periapical lesion. Conventional retreatment was not feasible due to the post, and implant therapy is a more successful mode of treatment than periapical surgery in cases of persistent periapical lesions or failed root canal treatment.^4,5 In light of this, the next decision to make was whether immediate or delayed implant placement was indicated after extracting the tooth and grafting the site.⁶

The patient presented with chief complaints of discomfort and a “pimple” that had formed above the maxillary left lateral incisor (Figs. 1a, 1b). Upon intraoral examination, the patient exhibited a small fistula apically in the area of tooth #10. Radiographic evaluation revealed that the tooth had received endodontic treatment, including a post and core procedure and a PFM restoration. A large periapical lesion approximately 7 mm in diameter was noted (Fig. 2).

The following treatment options were discussed with the patient:

1. Endodontic retreatment of the tooth and fabrication of a new crown.

2. Extraction of the tooth and restoration of the edentulous space with a removable partial appliance.

3. Extraction of the tooth and restoration with a fixed bridge.

4. Extraction of the tooth followed by immediate or delayed placement of an implant.

The patient selected option No. 4 and was advised that, following tooth extraction, the decision of whether to proceed with immediate or delayed implant placement would depend on the size of the resultant lesion and the ability to gain sufficient primary stability.

The patient was started on amoxicillin three days prior to surgery and would continue for seven days after. Profound anesthesia was attained utilizing a labial and palatal infiltrate of 4 percent Septocaine^® (Septodont; Lancaster, Pa.). Because it was unknown whether an implant could be placed at the time of surgery, a conservative flapless approach was utilized. To preserve soft tissue and facilitate an atraumatic extraction, a Spade Proximator™ (Karl Schumacher; Linden, N.J.) was used to loosen and separate the root from the PDL fibers (Fig. 3). A pair of sharp-beaked forceps was used to remove the tooth while preserving the hard- and soft-tissue architecture (Fig. 4).

A serrated curette was used to degranulate the socket and bony lesion. While excavating cystic tissue from the lesion, a large labial defect was identified. In light of this finding, the decision was made to carry out a full-thickness periodontal flap. To minimize any potential cosmetic issues, a sulcular incision with a release along the distal line angle of tooth #11 was performed. After flap reflection, the size of the lesion was evaluated.

Complete degranulation was performed first with a curette and finished with a No. 8 round bur on a slow-speed handpiece. It is crucial to success to make sure that all potentially bacteria-infected bone is removed. If bacteria from the periapical lesion has the opportunity to colonize the new implant site, the outcome can be compromised, with enterococcus faecalis as a common culprit in these types of cases.⁷

Once healthy, bleeding bone was exposed, the lesion left only a 5 mm bridge of bone labially at the crest (Fig. 5). However, sufficient bone was evident to facilitate immediate implant placement with the proper selection and use of allograft material, a collagen membrane and a 3.0-mm–diameter implant.

A high-speed handpiece with a long surgical carbide fissure bur was used to enter the palatal aspect of the lamina dura at about 3/4 of the depth of the socket. Once a purchase point was established, a 1.5 mm twist drill was used to create an osteotomy at the proper trajectory (Fig. 6). The pilot hole was opened up with a 2.4/1.5 mm twist drill, and a 2.8/2.4 mm x 13 mm twist drill established the final trajectory and osteotomy depth. This facilitated positioning for the implant beyond the apex of the socket, with the platform slightly subcrestal (Fig. 7). The full-thickness flap allowed visualization of the final osteotomy within the labial defect (Fig. 8).

When working with a patient in deciding the best long-term solution for a failing tooth, many factors must be taken into account and sometimes the final treatment direction cannot be determined until the time of surgery. Immediate placement of dental implants in extraction sites is a proven method with a high success rate.⁸ Even when a large defect is present, in many cases properly selected allograft material and modern implant design allow for predictable bone regeneration while the immediately placed implant integrates and the extraction site heals. When carried out correctly, this type of treatment can shave months off a treatment plan and provide high satisfaction for both the practitioner and patient.