Management of Retrograde Peri-implantitis: The Minimally Invasive Tunnel Approach

INTRODUCTION
Retrograde peri-implantitis, also referred to as an implant periapical lesion, can be described as a radiographic lesion around the apical portion of a dental implant that typically develops within the first few months after insertion.¹ This lesion, which was first described by McAllister et al,² has a rare reported prevalence. Reiser and Nevins³ reported 10 cases among 3,800 implants placed (0.26%), while Quirynen et al1 found 10 cases among 539 implants placed (1.6% of maxillary implants and 2.7% of mandibular implants).

This lesion can be classified as inactive or active, depending on clinical signs and symptoms of infections.³ The inactive form is asymptomatic and based on the presence of a radiolucency around the apex of the implant. This corresponds to an apical scar caused by vertical over-preparation or bone necrosis due to overheating during implant bed preparation. Treatment involves regular radiographic and clinical monitoring for changes. Active lesions are symptomatic, with clinical signs and symptoms that can include gingival reddening, pain, swelling, and presence of a fistulous tract. These lesions require surgical intervention.

Surgical Treatment Approaches
A number of surgical treatment approaches have been documented with success. Curettage of the lesion followed by irrigation with saline solution is a treatment modality that is often employed. Various chemotherapeutic agents have also been used by other clinicians, such as chlorhexidine or tetracycline paste; however, since most of the data is retrospective in nature and limited to case reports and series, evidence regarding the efficacy of one approach vs another is limited. Following surface decontamination, guided bone regeneration utilizing various bone replacement materials and membranes is often performed. Alternatively, other clinicians have documented success utilizing an apicoectomy approach,⁴ whereby the affected area of the implant is resected.

Figure 1. Preoperative radiograph.	Figure 2. Implant at insertion.	Figure 3. Three-month postoperative radiograph.

Traditionally, surgical procedures with bone augmentation techniques are performed with flap elevation, which often involves critically aesthetic papillary and facial tissue. This can result in gingival defects and scar formation,⁵ which underscores the need for a less invasive approach. Tunneling techniques have been reported with mixed success.^6,7 A more recent case series demonstrated success with a combination of xenograft and rhPDGF-BB, utilizing a tunnel approach8 that included treatment of previously exposed implant surfaces. Mean horizontal bone gain in these sites was 4.87 mm, although it was not disclosed whether these sites presented with periapical or gingival lesions.

The following case report demonstrates successful treatment of an implant periapical lesion in a highly aesthetic area where the soft-tissue contours were ideal. A minimally invasive tunnel approach avoided disturbance of the coronal gingiva via flap elevation or by compromising the blood supply via an apicoectomy-type flap.

CASE REPORT
Diagnosis and Treatment Planning
A 42-year-old African American male was referred by his general dentist to evaluate tooth No. 8 for extraction and implant placement. A comprehensive oral examination was done to assess his overall health. He presented with a 10-plus-mm palatal probing depth on a previously root canal treated tooth No. 8, along with a horizontal crown fracture (Figure 1). A vertical root fracture was diagnosed, and the tooth was treatment planned for extraction and immediate implant placement. A cone beam computed tomography (CBCT) scan was taken, and impressions were made for an interim partial denture. Immediate provisionalization would not be done in this case because the patient thought he would have difficulty in complying with the functional restrictions. In addition, he had no concerns with wearing a removable prosthesis while the implant integrated.

Clinical Protocol
One hour before surgery, the patient was premedicated with 2 g of amoxicillin and 600 mg of ibuprofen. The area was anesthetized via buccal and palatal infiltration with 4% articaine; 1:100,000 epinephrine (Septocaine [Septodont]).

The tooth was then atraumatically extracted with periotomes, elevators, and forceps. Next, the intact socket was debrided with surgical curettes, along with lavages of a 0.12% chlorhexidine rinse (Peridex [3M]) and saline solution. A 4.6 × 10.5 mm implant ( Tapered PLUS [BioHorizons]) was immediately placed in position to facilitate a screw retained restoration (Figure 2). The gap between the implant and socket was grafted with deproteinized bovine bone (MinerOss X [BioHorizons]), and a customized PEEK healing abutment was fabricated by adding composite resin (Filtek Supreme Ultra Flowable Restorative [3M]) to the abutment until light contact was made with the gingival tissues. The customized healing abutment was adjusted until flush with the gingival margin, and then the intaglio surface of the temporary prosthesis was relieved so as to not contact the abutment.

Figure 4. Fistula present at 5 months post-insertion.	Figure 5. A CBCT scan—note the coronal 3 mm of intact bone.
Figure 6. A single vertical incision and tunnel elevation.	Figure 7. Sutures after guided bone regeneration.
Figure 8. One-week post-op.	Figure 9. One-year post-op radiograph.

Figure 10. One-year post-op clinical view.

Three months after implant placement, a periapical radiograph (Figure 3) was taken. Healing was within normal limits, and the patient was referred to his general dentist. A screw-retained temporary crown was fabricated using a PEEK Temporary Cylinder (BioHorizons) and Protemp Temporization Material (3M), which was subgingivally contoured with a composite resin (Filtek Supreme Ultra Flowable Restorative).

Two months later, an asymptomatic fistula appeared on the facial aspect of the implant 4.0 mm apical to the gingival margin (Figure 4), and the patient was referred back for evaluation. Probing depths around the implant were 3.0 to 4.0 mm circumferentially, and the implant sulcus did not communicate with the fistula. A CBCT scan was taken; it demonstrated perforation of the apical two-thirds of the implant with intact coronal bone support (Figure 5).

The area was anesthetized via buccal and palatal infiltration with 4% articaine; 1:100,000 epinephrine (Septocaine). A vertical incision was made distal to the implant, and a full-thickness flap was elevated via a tunnel approach (Figure 6), which was extended 5.0 to 7.0 mm beyond the fixture apically and mesiodistally. Coronally, the elevation extended just beyond the fistula so as not to disturb the soft-tissue profile. The implant was then debrided with a piezo scaler (Satelec [ACTEON]) from the incision access, and multiple lavages of 0.12% chlorhexidine rinse and saline solution were administered. An Er,Cr:YSGG laser (Waterlase iPlus [BIOLASE]) was then used, with a radial firing laser tip (1.5 Hz, 40% Water, 40% air) being directed through the fistula and in a constant up and down motion to avoid overheating the implant surface and adjacent tissue. A collagen membrane (Cytoplast RTM [Osteogenics Biomedical]) was inserted into the flap, and deproteinized bovine bone (MinerOss X) was placed between the implant surface and membrane. Primary closure was achieved with single interrupted 4-0 Chromic gut sutures (Figure 7). Postoperative medications included amoxicillin, 500 mg TID for 7 days; ibuprofren, 600 mg q6h prn; and 0.12% chlorhexidine rinse to be used BID. The patient was seen for follow-up care, where healing was uneventful after one week (Figure 8). Minimal post-op discomfort was reported by the patient. After 6 months, the final crown was placed. A one-year follow up demonstrated stable soft tissue with no evidence of fistula recurrence and an absence of any clinical symptoms (Figures 9 and 10).

DISCUSSION
This article reports on the successful treatment of an active implant periapical lesion in a highly aesthetic area that was treated with a tunnel approach. This minimally invasive procedure maintained the facial soft profile and papillary areas, as a single incision was made distal to the defect and apical to the gingival margin. A guided bone regeneration procedure was then performed to cover the exposed implant surface.

Previous studies have documented successful treatment of implant periapical lesions utilizing a traditional flap approach and guided bone regeneration.^9-11 Many of these studies employed bone graft material in combination with a barrier membrane. Although the membrane serves to contain the graft material and exclude cells that can resorb the graft, it will also exclude potential osteoprogenitor cells that are present in the periosteum. The necessity of a barrier membrane in guided bone regeneration procedures has also been questioned.¹² Lee,⁸ using a similar technique to this article, demonstrated successful treatment without a barrier membrane placement. The author of this report decided to use a membrane in this case to avoid exfoliation of the graft particles through the soft tissue due to jagged edges that can occur on particulated xenogeneic bone. It has been the author’s experience that these particles can be visible through thin tissue, giving a lumpy, white appearance.

CLOSING COMMENTS
This case report demonstrated a minimally invasive technique to treat retrograde peri-implantitis in a highly aesthetic region. Fortunately, this type of lesion is relatively rare in occurrence; however, this makes larger, randomized studies, which would provide further evidence regarding the efficacy of this technique, unlikely.

References

1. Quirynen M, Vogels R, Alsaadi G, et al. Predisposing conditions for retrograde peri-implantitis, and treatment suggestions. Clin Oral Implants Res. 2005;16:599-608.
2. McAllister BS, Masters D, Meffert RM. Treatment of implants demonstrating periapical radiolucencies. Pract Periodontics Aesthet Dent. 1992;4:37-41.
3. Reiser GM, Nevins M. The implant periapical lesion: etiology, prevention, and treatment. Compend Contin Educ Dent. 1995;16:768-772.
4. Balshi SF, Wolfinger GJ, Balshi TJ. A retrospective evaluation of a treatment protocol for dental implant periapical lesions: long-term results of 39 implant apicoectomies. Int J Oral Maxillofac Implants. 2007;22:267-272.
5. Cosyn J, Sabzevar MM, De Bruyn H. Predictors of inter-proximal and midfacial recession following single implant treatment in the anterior maxilla: a multivariate analysis. J Clin Periodontol. 2012;39:895-903.
6. Block MS, Kent JN, Ardoin RC, et al. Mandibular augmentation in dogs with hydroxylapatite combined with demineralized bone. J Oral Maxillofac Surg. 1987;45:414-420.
7. Nevins ML, Camelo M, Nevins M, et al. Minimally invasive alveolar ridge augmentation procedure (tunneling technique) using rhPDGF-BB in combination with three matrices: a case series. Int J Periodontics Restorative Dent. 2009;29:371-383.
8. Lee EA. Subperiosteal minimally invasive aesthetic ridge augmentation technique (SMART): a new standard for bone reconstruction of the jaws. Int J Periodontics Restorative Dent. 2017;37:165-173.
9. Bretz WA, Matuck AN, de Oliveira G, et al. Treatment of retrograde peri-implantitis: clinical report. Implant Dent. 1997;6:287-290.
10. Chan HL, Wang HL, Bashutski JD, et al. Retrograde peri-implantitis: a case report introducing an approach to its management. J Periodontol. 2011;82:1080-1088.
11. Chang LC, Hsu CS, Lee YL. Successful medical treatment of an implant periapical lesion: a case report. Chang Gung Med J. 2011;34:109-114.
12. Gielkens PF, Bos RR, Raghoebar GM, et al. Is there evidence that barrier membranes prevent bone resorption in autologous bone grafts during the healing period? A systematic review. Int J Oral Maxillofac Implants. 2007;22:390-398.

Dr. Waasdorp received his dental degree from the University of Pennsylvania, where he graduated with honors in pharmacology and received National Board of Dentistry Parts I and II honors. He then completed a 3-year residency at the University of Maryland and specialized in periodontics and advanced implant dentistry. In his final year of residency, Dr. Waasdorp was selected as the recipient of the American Academy of Periodontology Lazarra Fellowship Award in Advanced Implant Surgery. This prestigious fellowship is awarded to the top periodontal resident in the country each year, in which the recipient engages in advanced implant surgical training along with teaching and research responsibilities. Dr. Waasdorp is in private practice in Bala Cynwyd, Pa, and is a clinical associate professor at the University of Pennsylvania. He can be reached at waasdorp@comcast.net.

Disclosure: Dr. Waasdorp reports no disclosures.

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