Placement of endosseous implant in infected alveolar socket with large fenestration defect: A comparative case report.

Placement of endosseous implants into infected bone is often deferred or avoided due to fear of failure. However, with the development of guided bone regeneration [GBR], some implantologists have reported successful implant placement in infected sockets, even those with fenestration defects. We had the opportunity to compare the osseointegration of an immediate implant placed in an infected site associated with a large buccal fenestration created by the removal of a root stump with that of a delayed implant placed 5 years after extraction. Both implants were placed in the same patient, in the same dental quadrant by the same implantologist. GBR was used with the fenestration defect being filled with demineralized bone graft* and covered with collagen membrane**. Both implants were osseointegrated and functional when followed up after 12 months.

INTRODUCTION

Immediate implant placement at a site with infection or bone deficiency or fenestration is usually avoided since the prognosis may be poor. However, lately there have been several publications that report the successful usage of guided bone regeneration (GBR) in such cases with suboptimal bone health. A systematic review of literature of such cases, published in 2010, summarizing data from published animal experiments, case reports, case series and prospective studies concludes that similar success rates have been reported for implants placed into infected sites compared to implants placed in non-infected sites.[1] Conclusions drawn from the results of recent comparative studies also suggest that the presence of chronic infection, periapical or periodontal, does not modify osseointegration.[2] A systematic review (2010)[3] of clinical outcomes of GBR procedures to correct peri-implant dehiscences and fenestrations associated with implant placement summarizes that in the majority of cases, a complete or an almost complete coverage of the initial defect was obtained and the overall survival rate was 95%.[3] Even though such studies are encouraging, placement of implants in such precarious conditions where the bone is both insufficient and infected, is still considered a risk. In this case report we have reported a case in which two implants were placed in the same quadrant of a patient who had a retained root stump in one of the edentulous spaces. Moreover, the removal of the root stump buccally resulted in a large fenestration defect. An implant was immediately placed into the debrided infected site. Another implant of the same design was placed in the other edentulous space, with sufficient bone density, from which the tooth had been removed 5 years back. We had the opportunity to compare the osseointegration of both these implants using clinical parameters.

CASE REPORT

History and preoperative assessment

A 29-year-old male patient was referred to the Department of Periodontology and Oral Implantology, with complaints of missing teeth in the left lower posterior region. History revealed that following a road-traffic accident, 34 and 36 had been extracted 5 years back. On intraoral examination, 34 and 36 were found to be missing [Figure 1a and 1b]. The patient complained of occasional, mild pain in the region. Radiographic [Figure 2] and computer tomographic (CT) examination of the edentulous spaces revealed a radio-opaque mass surrounded with radiolucency in the 34 region distal to 33. It was diagnosed as a retained root stump by the radiologist. CT [Figure 3] revealed that the root stump was placed more buccally and had good bone coverage coronal to it. The patient was given the option of extraction followed by implant placement. Pros and cons of the procedure were explained to the patient and informed consent was obtained. Preoperative evaluation included study of diagnostic casts, photographs, periapical radiograph and CT for assessment of implant size, position of implant and anatomical landmarks.

Figure 1a

Pre-operative intraoral appearance - missing 34 and 36 b: Pre-operative intraoral appearance - missing 34 and 36

Figure 1b

Pre-operative intraoral appearance - missing 34 and 36

Figure 2

Pre-operative IOPA of 34 region showing retained root fragment

Figure 3

Pre-operative CT image showing retained root fragment

Procedure

After administration of local anesthesia [2% Lignocaine 1:80000 adrenaline], a crestal incision was placed in the edentulous 34 region; vertical relieving incision was placed in relation to 33. A full-thickness mucoperiosteal flap was elevated and reflected. Implant site was marked with round bur. A 2-mm pilot drill osteotomy was done to the depth of 3 mm. On encountering an obstruction on drilling beyond 3 mm, the region was marked and the root stump carefully removed [Figure 4] through a buccal approach [Figure 5]. The socket was then thoroughly debrided and curetted to eliminate all the visible granulation and infected tissues [Figure 6]. Consequently, a restrained peripheral intrasocket ostectomy of the alveolar bone was performed using bone scoop to ascertain absolute eradication of all infected soft and hard tissues with special attention to the periapical region. The surgical site was vigorously irrigated with a sterile solution. Sequential implant drilling was done for the site to receive a 4.2x10-mm length implant***. Implant was placed with a torque wrench with adequate primary stability. The implant had a large buccal fenestration of 5 mm [Figure 7]. The void was filled with bone graft [Figure 8] and GTR collagen membrane** was placed and stabilized coronally with the implant cover screw [Figure 9] and sutures to stabilize the membrane apically. Flap repositioned and sutured with simple interrupted sutures using non-absorbable catgut material. Primary closure was achieved. Immediate postoperative radiograph was taken to confirm position of both implants [Figure 10]. Temporary restoration was provided using an adhesive resin bridge. Antibiotics and analgesics were prescribed for 5 days. Patient was placed on regular maintenance protocol.

Figure 4

Removed root fragment

Figure 5

Buccal entry for removing the root fragment

Figure 6

After removal of the root fragment, the granulation tissue is curetted and ostectomy done to remove infected bone

Figure 7

Implant place - large fenestration defect

Figure 8

Filling the defect with DMBM

Figure 9

Collagen membrane tacked coronally using the implant cover screw and apically using resorbable sutures

Figure 10

Immediate post-operative IOPA showing both implants

A similar implant was placed uneventfully in the 36 region also, following standard protocols.

Postoperative Assessment

Four months after placement, the implants were exposed by a minimal crestal incision and mounted with healing caps, and 1 month later the implants were mounted with the permanent abutments [Figure 11] and loaded with the final restoration. At the 1-year follow-up examination [Figure 12], both implants were functioning and were fully osseointegrated [Figure 13]. Clinical parameters probing depth, modified plaque index, modified bleeding index, marginal gingiva level and keratinized mucosa and marginal bone levels were evaluated. No significant difference was noted between the two implant restorations. The receptacle dentoalveolar sockets showed good healing.

Figure 12

Post-operative clinical appearence of the loaded implants after 12 months

Figure 13

Post-operative radiographic appearence of the loaded implants after 12 months

DISCUSSION

Several authors[4-9] have reported that implants inserted in deficient alveolar ridges with intrabony defects, even infected extraction with fenestration defects could be successfully treated with grafts along with barrier membranes. Reporting a series of 30 implants immediately placed into debrided infected sites in 20 patients, Cassap et al. concludes that successful immediate implantation in debrided infected alveoli depends on the complete removal of all contaminated tissue and the controlled regeneration of the alveolar defect. With this proposed clinical approach, experienced clinicians may consider immediate implants as a viable treatment option in patients presenting with dentoalveolar infections.[8]

A systematic review[3] of clinical outcomes of GBR procedures to correct peri-implant dehiscences and fenestrations concludes that despite obtaining favorable results, it was difficult to draw a significant conclusion as far as the more reliable grafting material and membrane barrier for the correction of dehiscence/fenestration defects are concerned, due to the limited sample of patients and the wide variety of grafting materials and membranes, used alone or in combination. However, they report that 20% of the non-resorbable membranes and 5% of the resorbable ones underwent exposure/infection.[3]

Additionally, resorbable membranes are preferred since non-resorbable membranes require a second procedure to remove the membrane and they show a high incidence of flap sloughing and membrane exposure, which often leads to infection and unfavorable results. Resorbable, collagen membranes are ideal since they do not require an additional procedure to remove the same. The collagen, physiologically metabolized macromolecule of the periodontal connective tissue, is cross-linked to control the amount of time it remains stable and functional. It is hydrophilic, chemotactic to fibroblasts, hemostatic, a weak immunogen and may also act as a scaffold for migrating cells. Collagen membranes are reported to offer minimal postoperative complications, a good healing rate and no incidence of material dehiscence, tissue perforation, sensitivity reactions, immune response, tissue sloughing, delayed healing or postoperative infection. Collagen is a useful and beneficial material for GBR because these membranes meet the criteria for membrane barrier techniques-creating a space, tissue integration, cell occlusivity, biocompatibility and clinical manageability.[10]

The standard protocol of placing a membrane uses miniscrews to pin the barrier membrane in a stable position.[7] In this case and in many other occasions, we have used sutures to stabilize the membrane apically and the cover screw of the implant to hold the membrane in place during healing. Suturing eliminates the fear of damage to adjacent teeth roots while placement, and tearing of thin covering flaps while draping over the protruding screw head.

CONCLUSION

All patients desire shorter waiting period until final restoration and fewer visits to the dentist therefore simultaneous implants are always desired. With the advent of GBR, even fenestration defects, infected bone and insufficient ridges do not deter the osseointegration of the implant if the protocols are strictly adhered to. The clinical outcome in this case suggests that there is no significant difference in the osseointegration of an immediate implant placed judiciously in an infected site associated with a large buccal fenestration created by the removal of a root stump when compared with that of the delayed implant placed in a healed alveolus, 5 years after extraction. Clinically, both implant sites demonstrated excellent periodontal health with relation to attached gingiva, interdental papilla and alveolar mucosa [Figure 11]. However, due to the lack of randomized clinical trials, it is still impossible to say with confidence that implants can be placed in all regions of infection and bone deficiency.

Figure 11

Abutment attached at 5 months

*DMBM Osseograft

**Healiguide collagen membrane

***Hi-Tec tapered threaded implant