Dental implants developing peri-apical disease: a case report

Implant peri-apical pathology has been referred to as apical peri-implantitis, retrograde peri-implantitis, or peri-apical implantitis. Implant peri-apical pathology was described by McAllister et al¹ as an injury that occurs in the apical portion of an implant causing failure of osseo-integration. Sussman and Moss² defined it as an infectious–inflammatory process of the tissues surrounding the implant apex.

The aetiology of peri-implant disease remains controversial. Some have suggested that it might be caused by bacterial contamination of the implant during the surgical procedure itself. Others have postulated that it might be caused by a resurgent peri-apical infection in that area, or possibly due to a retained root tip, or by infection spreading from the peri-apical lesion of an adjacent tooth.³ Other suggested explanations for implants developing localized peri-apical pathology have included overheating at the tip of the final drill and/or overloading of the bone.³

The reported incidence of apical radiolucencies around implants ranges from 0.26% to 7.8%, and it has been reported that the incidence may be reduced by increasing the distance between the implant and the adjacent tooth. Furthermore, increasing the duration from root canal treatment of an adjacent tooth and implant placement may also reduce the incidence.^4,5 Peri-implant lesions can appear inactive and asymptomatic clinically, which may not correlate with the radiographic appearance of the lesion. Examples of inactive lesions appearing radiographically include when the osteotomy site prepared is longer than the implant fixture placed, when the implant is placed in close proximity to a pre-existing bone deficiency due to scar tissue or a bony crypt left from an area of granulation tissue.^1,5 Radiolucent lesions can also be caused by overheating the bone when preparing the osteotomy site. Moreover, active lesions are usually associated with symptoms, and caused by bacterial contamination. This can occur during insertion, or as a result of placing an implant into an area of infected granulation tissue or cystic lesions.⁷

Shah et al⁶ proposed a classification system for peri-apical implantitis based on the radiographic assessment of the extent of apical bone loss, measured from the apex of the implant to the most coronal point of extension. This is expressed as a percentage of the radiographic length of the implant in bone.

• Class I: Mild (<25% bone loss);
• Class 2: Moderate (25–50% bone loss);
• Class 3: Advanced (>50% bone loss).

Figure 1 shows an example of class 2 (moderate) peri-apical implantitis with 25–50% bone loss around the apical part of the implant with coronal bone being unaffected. Figure 2 is an example of a class 3 (advanced) peri-apical implantitis lesion, according to Shah et al,⁶ with more than 50% of the bone missing from around the apical portion of the implant. Figures 1 and 2 were taken of the same case 6 months apart and show the rapid progression of peri-apical implantitis, from moderate to advanced. Unfortunately, this patient refused the offer of apical surgery, despite being shown clear evidence of the bone loss and progression of the lesion. Detailed clinical notes documented the discussions and treatment recommendations, but the clinical team had to accept that the patient was exercising her autonomy in refusing the proposed surgical treatment (Montgomery consent).

This article illustrates a case with moderate peri-apical implantitis in the maxillary arch, which was treated successfully with apical surgery.

History

This case report illustrates a 51-year-old female who attended a trauma clinic 6 days after falling down some stairs and traumatizing her upper left central incisor (UL1). She complained of pain and mobility from this tooth, as well as an inability to bite using her front teeth. Medically, she had well-controlled type II diabetes and was taking metformin. She also experienced intermittent psoriasis, and was a non-smoker. Clinical examination revealed a fractured UL1 with grade III mobility. The tooth was discoloured (Figure 3) with a palatal access cavity sealed with a plastic restoration. The patient reported that it had been root filled many years previously.

Generally, her dentition was well cared for, and her periodontal health was good with basic periodontal examination codes of 0s and 1s. A peri-apical radiograph of the UL1 (Figure 4) revealed:

• Good bone levels;
• Root filling obturated to the apex and well condensed without voids;
• Radiolucency on the distal surface of the crown;
• Loss of continuity of crown-root profile on the mesial-cervical surface.

Based on the history, detailed clinical examination and the radiographic presentation, a diagnosis of a crown-root fracture in the UL1 was made. The patient was informed of the poor prognosis for this tooth. The various different treatment options were then discussed in detail, with reference to the short and long-term challenges, as well as the problem posed by her pre-existing midline diastema.

After lengthy discussion, she was consented to acute trauma management followed by replacement with a single tooth implant-retained crown. Owing to her low lip line, the decision was made to place an immediate implant.

The left maxillary central and lateral incisors (UL1 and UL2) were splinted temporarily using rectangular wire and composite resin (Figure 5), to facilitate taking alginate impressions for an immediate denture to be constructed. This was designed as a gum-fitted, horseshoe-shaped acrylic denture.

At the subsequent appointment, the UL1 was extracted atraumatically with the aid of a luxator. The socket was debrided and prepared for a Neoss implant (Neoss, Harrogate) (4 x 15 mm) to be placed, which was followed by the placement of a cover screw. The immediate partial denture was fitted, and the patient was given post-operative instructions including how to clean the denture effectively.

The peri-apical radiograph of the UL1 implant (Figure 6) revealed:

• Good mesio-distal positioning.
• Socket space coronally between the implant and the alveolar wall.

One month after the extraction and placement of the implant, the patient reported swelling associated with the implant in the upper left central incisor region (UL1). She attended her local emergency department where she was prescribed antibiotics. She was reviewed 3 days later in the specialist clinic and there was no sign of any swelling. The UL1 implant appeared stable and the patient was reassured and given further oral hygiene instruction.

Four months after implant placement, the implant was exposed under local anaesthesia and an impression was taken using a polyether material with an impression coping in an open stock tray. A 5-mm healing abutment was placed and the patient was advised on how to clean around it. A shade was taken, and the denture was modified to accommodate the healing abutment.

Four weeks later, the soft tissues had healed, and the patient reported that she had no problems (Figure 7). The screw-retained implant crown was tried in under local anaesthesia and the patient was happy with the appearance. The crown was then secured to 40 Nm², and the access cavity was filled with polytetrafluoroethylene (PTFE) tape and composite resin.

The patient was reviewed 6 months later, and remained happy with her UL1 implant-retained crown (Figures 8 and 9).

The peri-apical radiograph taken of the UL1 implant at the 6-month review appointment (Figure 10) revealed:

• Coronal bone deficiency around the UL1 implant.
• A possible diffuse peri-apical radiolucency around the distal aspect of the implant.

At the 1-year implant review, the patient complained of a constant, low-level, nagging pain, which she described as being similar to the pain she had experienced after the root canal treatment of the UL1. This had started over the past few months and, although analgesics were not necessary, the symptoms were slowly increasing in intensity. Clinically, the UL1 implant crown was secure and firm. There was no periodontal pocketing or bleeding on probing. She indicated that palpation of the soft tissues felt ‘different’ around the UL1 implant compared to the UR1, but was not painful.

The peri-apical radiograph revealed an increase in the size and the radiolucency of the apical lesion associated with the UL1 implant (Figure 11). In order to aid planning, a cone beam computed tomography (CBCT) scan was requested. The CBCT report stated that the UL1 implant had a 9 mm, well-defined radiolucency around the apical half of the implant, with reactive sclerosis of the surrounding bone. The buccal cortex had been perforated, and the radiolucency was close to the nasopalatine canal (Figure 12).

The various management options available were discussed in detail, including the unpredictability of the outcome of surgery. The patient consented to surgical exploration of the lesion associated with the UL1 implant, and enucleation of the pathology at the apex of the implant.

A full-thickness flap was raised over both maxillary central incisors with two relieving incisions exposing the dehiscence of bone over the UL1 implant apex (Figure 13). Without removing any further bone, the soft tissue lesion was enucleated and sent for histopathological analysis. The exposed bony crypt around the apical 8 mm of the implant is shown in Figure 14.

Ultrasonic debridement of the apical part of the implant was carried out, followed by etching with 37% phosphoric acid for 60 seconds. The thixotropic gel was aspirated carefully, and then followed by copious irrigation with saline.

Bio-Gide (Geistlich, Manchester) was placed over the dehiscence, and the flap was closed using resorbable sutures. The patient was prescribed a course of 500 mg amoxicillin antibiotics to be taken three times a day for 5 days.

Follow up and histopathology report

The histopathology report of the lesion revealed fibrous tissue containing a diffuse mixed chronic inflammatory cell infiltrate. The periphery had remodelled bone present, but with no epithelium, and a diagnosis of peri-apical implantitis was made.

At the 6-month review following surgery, the patient was asymptomatic, and a peri-apical radiograph revealed that the peri-apical radiolucency around the implant had reduced in size and there was some evidence of bony infill (Figure 15). At the 18-month review following surgery, the patient remained asymptomatic and there was evidence of complete bony healing on the peri-apical radiograph (Figure 16).

Discussion

In theory, the advantages of immediate implants, compared to delayed placement, include reduced bone resorption of the extraction socket, better aesthetics and shortening of the total treatment period.⁸ Placing implants immediately is becoming more common in an attempt to preserve the labial bone.⁹ They are, however, only suitable in appropriate cases.

The failure rate for immediate implants has been reported as being as low as 0.5–1.4% at 2 years, although it is possible that these results may be skewed by selection and reporting bias.¹⁰ A retrospective study looking at 1022 implants found that the survival rates were 93.8% for immediate implants and 93.2% for delayed placement implants.¹¹ A systematic review by Lee et al¹² predicted the survival of immediate implants in infected sites to be 96.2% at 5 years. Interestingly, another systematic review found that peri-apical infection was a good predictive marker of peri-implant disease and implant failure.⁹

A review of the literature advises debridement of the extraction socket to remove granulomatous tissue before placing the implant, but some advocate the use of antibiotics and bone grafting.³

Important attention to detail with the technical aspects of placing implants involves avoiding the introduction of bacteria into the osteotomy site, water cooling to prevent overheating the bone, and light torquing forces. However, it cannot be guaranteed that all bacteria are eradicated from the apical pathology of the extracted tooth.³

In this case report, the UL1 had been root treated many years previously. The peri-apical radiograph that was taken for the initial assessment did not appear to demonstrate an apical radiolucency. However, a study by Green et al¹³ found that five of 19 (26%) endodontically treated teeth from cadavers, which did not show obvious apical radiolucency on the peri-apical radiograph, showed histological signs of inflammation. Albeit a small laboratory study by Green et al,¹³ it is possible to speculate that there might have been some degree of chronic apical inflammation still present in this case at the time of implant placement, which might have contributed to the development of the peri-apical implantitis.

Despite the fact that the implant appeared to be placed in a good position relative to the crestal bone (Figure 6), the bone healed to the second thread on the implant as seen in the radiograph of the implant crown 6 months after fitting (Figure 10). Fortunately, this did not present an aesthetic problem to the patient, and the bone level remained stable 18 months after the peri-implant surgery (Figure 16).

This case report demonstrates the successful surgical management of peri-apical implantitis to be very similar in terms of surgical approach to carrying out root end surgery on an endodontically treated tooth. It is the opinion of the authors that if left, the area might well have continued to progress and thereby result in failure of the implant.

Regular radiographic follow up of patients who have had implants placed to monitor for peri-apical and coronal bone loss is, therefore, very important. Localized apical pathology, and consequent radiographic changes, can develop later around dental implants. The evidence suggests that the pathology is bacterial in origin, but the aetiology may well be multifactorial with many possible contributing factors.

Clinicians who place immediate implants should be aware of these known risks, and educate patients of the material risks and benefits of having, or not having, different treatment options. This ensures the patient has given informed consent, in line with the Montgomery ruling on clinical and medicolegal practice.¹⁴