11
Immediate Implant Placement in Infected Tooth Sockets
Mahdi Kadkhodazadeh, Anahita Moscowchi, and Reza Amid
Introduction
Immediate dental implant placement (IIP) has become more or less routine in the hands of knowledgeable and experienced clinicians, making replacement of hopeless teeth with dental implants more appealing to patients. Originally, it was considered inappropriate to take the IIP approach at sites where teeth were lost due to periapical/endodontic or periodontal infections [1]. In such situations, it was felt that the affected teeth should first be extracted, and their sockets allowed to heal for several months with resolution of the infection to avoid complications such as failure to integrate or loss due to retrograde peri‐implantitis where full eradication of the responsible microorganisms had not been achieved. Unfortunately, taking this delayed implant placement approach resulted in extensive alveolar ridge shrinkage starting almost immediately following tooth extraction and often leaving inadequate bone for implant placement. This is particularly an issue in anterior maxilla where very thin (< 1 mm) buccal bone plates will disappear within 6–8 weeks, leaving ridge width woefully inadequate buccopalatally [2]. Fortunately, it has been discovered that when executed properly, IIPs can significantly reduce this ridge shrinkage. Additionally, it seems that asymptomatic chronic local infection is not a concern regarding IIP procedures [3–5]. Systematic literature reviews have indicated that immediate implants placed in chronically infected sites generally perform similarly to those placed in healed sites provided protocols including thorough debridement and systemic antimicrobials are employed [6, 7]. However, A meta‐analysis reported 116% increase in the risk of implant failure with a borderline statistical significance (risk ratio = 2.16, p = 0.058) [40]. Obviously though, sufficient native bone must remain to adequately stabilize the implant, which may be an issue if the infection has destroyed so much apical bone as to make this impossible.
Not all periapical lesions associated with hopeless teeth are caused by infection, as some may be attributed to non‐infectious conditions like odontogenic keratocysts or radiolucent lesions that arise due to previous apicoectomies without grafting with bone substitutes, but this chapter specifically focuses on infected sites.
Tooth‐related infections can be acute or chronic and of periodontic or endodontic origin. IIPs are generally considered inappropriate for acutely infected sites such as periapical and periodontal abscesses. However, if the presenting infection is subacute, asymptomatic and untreated, the associated bacteria can become dormant, and it is these types of infected sites that are often good cases for IIP.
There is a lack of definitive evidence regarding the types of microorganisms harbored in chronically infected extraction sockets, with most available data coming from studies of endodontic lesions. Bacteroid species that colonize periapical lesions can develop greater virulence and persistence by forming protective polysaccharide capsules. Tannerella forsythia, for example, is one such organism, and can lie dormant in bone after tooth extraction due to pulpal necrosis or failed endodontics [8]. However, a variety of other organisms can persist in periapical, sclerotic bone, despite apparent normal socket healing after tooth removal [9]. Later, these microbes may become reactivated following instrumentation for the placement of dental implants resulting in retrograde peri‐implant apical infection. Particularly difficult to eradicate are Actinomyces species [10], which may require extended antibiotic treatment for resolution. Such situations may have contributed to the findings of one recent meta‐analysis, which suggested that immediate implants placed in infected sites had three times the risk of failure as those placed in non‐infected sites [11]. Findings by Nelson and colleagues [9] are of relevance here. These investigators collected microbiological samples from 16 preimplant extraction sites, 56 healed post‐extraction osteotomies at fixture placement, and five failed implants. Tissue fluids and biopsied bone samples were analyzed by either anaerobic/aerobic culturing or DNA molecular techniques. A total of 11 (69%) of the 16 preimplant extraction sockets were positive for the presence of bacteria. In the 56 osteotomies created at sites that all had healed for at least 3 months post‐extraction, 21% revealed a positive culture. All five failed implants gave positive cultures, and it was evident from radiographs that all five had their apices located close to the former tooth root ends. The dominant bacterial species were Streptococcus (35%), Actinomyces (18%), Veillonella (12%), and Lactobacillus (12%). Gram‐positive species accounted for 71% of the bacteria, while 46% were obligate anaerobes. The investigators suggested that bacteria remained sequestered in the sclerotic cortices that had surrounded the former tooth apex infections, and based on these findings developed a microbiologically based surgical debridement strategy. They proposed that after an infected tooth is removed and all granulation tissue has been extirpated, a largish, slow‐speed, round bur with a long shaft should be used to remove any sclerotic apical bone with exposure of normal trabecular bone. This rotary debridement was continued until overt hemorrhage ceased and only punctuate point bleeding was evident clinically.
Naturally, the overall health of the host is an important consideration in regard to using IIPs, and certainly patients with poorly controlled diabetes with their compromised resistance to infection are not good candidates. Other poor candidates may be smokers, heavy alcohol consumers [12], severely obese individuals [13], those with chronic stress issues or using certain mood‐altering medications (e.g. selective serotonin reuptake inhibitors [14]) or patients with regular need of anti‐inflammatory medications such as glucocorticoids and non‐steroidal anti‐inflammatory drugs (NSAIDs) [12].
Numerous indices have been proposed to assess and categorize fresh extraction sockets. Typically, these classifications rely on evaluations of the condition of both hard and soft tissue morphologies as well as on patient health factors [15–17]. By making slight adjustments, these same indices can be used to categorize infected extraction sockets and their appropriate management (Table 11.1). Parameters such as source of infection, rate of progression, infection history, degree of infection extension, and severity of hard and soft tissue defects must be taken into account to accomplish this goal.
With regard to origin of the infection, periapical endodontic lesions are typically isolated, often making their sockets suitable for IIP treatment (Figure 11.1). In contrast, periodontal infection may be generalized, requiring extraction of multiple infected teeth to arrest the disease before any implant treatment can be considered (Figure 11.2). However, if such a patient has previously undergone successful periodontal treatment and is being well maintained but later presents with an isolated periodontally infected tooth requiring removal, IIP may be considered provided that the remaining bone will allow acceptable three‐dimensional implant positioning.
Table 11.1 Infected socket multifactorial classification.
| Criteria | Classification |
|---|---|
| Origin | Endodontic, periodontal, etc. |
| Progression | Acute, chronic |
| Extension | Periapical, radicular, interproximal, combined |
| General considerations for immediate implantation | Systemic health, bone metabolism, tissue healing capacity, primary stability, tissue phenotype, lip line |
Tooth replacement with IIP is a complex treatment and it is important for the clinician to decide whether it is appropriate. Addressing compromised sockets requires a high level of clinical expertise and a deep understanding of biology for effective management (Figure 11.3a–e). In these cases, adopting more conservative approaches like early or delayed implant placement protocols is recommended for less experienced clinicians. The XV European Workshop in Periodontology [18] highlighted the fact that periapical infection is not an absolute contraindication for an IIP. However, other key factors in the decision process include the condition of socket walls, the soft tissue quantity and phenotype, and the likelihood of being able to achieve adequate primary implant stability. Again, if not appropriate for IIP, the site could be considered for early (4–8 weeks post extraction) implantation with or without prior socket preservation grafting or even delayed placement again following such grafting. A review of 12 clinical trials revealed no significant difference in implant failure rates between immediate and early implants placed into intact tooth root sockets [19]. However, marginal bone loss in the early group was significantly lower (p = 0.001) than in the immediate group (by 0.14 mm). The clinical relevance of the difference seemed questionable.
Figure 11.1 (a) The patient presented with a history of trauma, which had resulted in a necrotic pulp at the maxillary right central incisor; although there had been significant bone destruction apically, thin but intact buccal bone remained. (b) Flapless extraction was achieved. (c) A bone‐level implant was inserted with xenogenoic bone substitute augmentation. (d) A radiograph of the final restoration after 7 months in function. (e) The corresponding clinical appearance.
Figure 11.2 (a–c) Replacing an infected tooth with an immediate implant is not appropriate in a patient with uncontrolled severe periodontitis.
Figure 11.3 (a) This patient’s left maxillary central incisor presented with an endodontic failure and root fracture. (b) A periapical lesion had developed causing a buccal bone perforation apically. (c) The extracted tooth and attached granulomas. (d) A bone‐level implant was placed 2 mm subcrestal with buccal augmentation using xenograft material. (e) A radiograph of the restored implant after approximately 8 months in function.
Another systematic review of 9 clinical studies involving 2281 fresh extraction sockets found no significant difference in the survival rates of immediately placed implants in infected versus non‐infected sockets (risk ratio 0.99) [20]. Similarly, there were no significant differences in marginal bone level, level of soft tissue margin, probing depth, or soft tissue bleeding. Additional data from five non‐randomized clinical trials and a meta‐analysis of three studies showed no significant difference between immediately placed implants in infected or non‐infected sockets regarding marginal bone levels, probing depths, level of soft tissue margins, and bleeding indices. A study of 86 patients who received 168 immediately placed implants found that the survival rates of those placed in extraction sockets with no infection, in sockets with chronic infection, or with acute infection were 98.8%, 100%, and 94.4%, respectively [21]. Therefore, it can be concluded that immediate implant placement can be a viable treatment option if the infected socket is completely debrided [22, 23]. In addition to clinical outcomes, analyzing the healing process around immediately placed implants in infected sockets using histological methods can yield valuable insights. An animal study on beagle dogs found no histological evidence of inflammation around implants placed in either previously infected or non‐infected sockets. Furthermore, after allowing sufficient time for healing (3 months in this study), there were no significant differences observed in buccal or lingual bone levels among the different groups studied (infected and non‐infected sockets, as well as implants manufactured with machining, sandblasted and acid‐etched, or sandblasted, acid‐etched and coated with a calcium solution) [24].
Treatment Steps
Extraction of Infected Teeth
Other chapters in this book have stressed the need for conservative approaches in extracting teeth planned for IIP. The presence of infection can either simplify or complicate this step. If the infection has caused partial loss of tooth support, extraction can be performed with less force. However, if thin buccal bone has been affected by the infection, the risk of bony wall fracture and loss increases making subsequent steps more complicated. Most clinicians prefer to extract teeth to be replaced with IIPs without elevating a flap unless it is required to remove broken root fragments. In cases where there is a history of infection, it is imperative to remove all the tooth, and techniques such as “socket shielding” that intentionally leave parts of the root in situ would not be advisable in the presence of infection (Figure 11.4a–h) [21, 25].
Using small surgical elevators and periotomes, together with magnification, can help to control the force applied during extraction and preserve adjacent tissues. Piezosurgery tips and ultrasonic instruments also can be helpful [22]. If the infection is confined to the apical region, and there is concern with maintaining papillae, an alternative approach for access and improved visualization in dealing with the infected defect could be to use a vestibular rather than a crestal incision and soft tissue reflection from above (Figure 11.5a–k).
Complete Debridement of Tooth Extraction Sockets
Often, apical granulomas at endodontically infected sites remain attached to the root apex following extraction. However, even in these cases, it is essential to provide intensive and careful curettage of the affected bone to increase the likelihood of complete eradication of the infection and associated inflammation. To address this issue, various instruments and techniques have been proposed. These include spoon‐shaped serrated curettes, titanium brushes, piezoelectric devices, repeated irrigation with sterile saline, or chemical disinfection with substances such as chlorhexidine or diluted 3% hydrogen peroxide solution (Figure 11.6). Other techniques involve the use of erbium or diode lasers [26] and antibacterial photodynamic therapy using a photosensitizer [27]. It has not been confirmed that there is an advantage to irrigating the socket with an antibiotic solution [6]. Additionally, no study has been conducted to compare the efficacy of any of these methods in eliminating residual infection using histological assessment. Currently, there are no clinically applicable methods to evaluate the adequacy of debridement achieved at infected sockets.
Platelet Concentrates in Infected Site Implantation
The use of autogenous growth factors in the form of leukocyte‐ and platelet‐rich fibrin (PRF) for socket preservation at extraction sockets can show significantly smaller reductions in bone height and buccolingual alveolar ridge diameter compared with control sockets [28]. However, the approach has not been found to provide consistent outcomes. Some case reports on the effective use of PRF with immediate implant insertion into extraction sites with periapical infection in the esthetic zone have been reported [29, 30], stressing the proliferative, anti‐inflammatory, and antibacterial effects of PRF in such situations. Others have reported statistically significant differences in implant stability at 1 week and 1 month when using PRF preparations [31], although not with immediate implants specifically [32, 33]. In vitro work has also shown significant reductions in bacterial counts from intentionally contaminated implant surfaces, most likely through the antimicrobial effect of platelets [34].
Figure 11.4 (a) The left central incisor presented with periapical infection and external root resorption. (b) The crown shape and soft tissue profile favored IIP. (c) Flapless tooth extraction was performed. (d) Immediate implant placement insertion. (e) The buccal gap was filled with xenograft hard tissue substitute material. (f) A xenogeneic soft tissue substitute was inserted into a pouch created buccally to thicken the marginal soft tissue. (g) The final restoration. (h) A radiograph of the restored implant.
Figure 11.5 (a) Both central incisors were deemed hopeless due to severe internal resorption. (b) After extraction, the sockets were debrided using a titanium brush. (c) A vestibular incision was used to expose the periapical lesion for debridement while maintaining the integrity of the marginal soft tissues. (d) Two implants were inserted leaving suitable gaps for grafting. (e) The collagen barrier material was trimmed to cover the defect and thicken the soft tissues. (f) After placing the barrier, the site was ready for hard tissue grafting using allogenic bone material, (g) The barrier was stabilized with pins to avoid its movement during healing. (h) The incision was sutured; note that the barrier material had been teased under the marginal tissues to thicken them and cover the implants for submerged healing. (i) A postoperative radiograph of the site. (j) The final clinical picture. (k) The corresponding radiographic image.
Source: Courtesy of Dr. Sadegh Mohammadreza.
Are Systemic Antibiotics Needed?
Many clinicians routinely prescribe systemic antibiotics after complex implant treatments, particularly for those that have included using biomaterials. Clinical evidence does not conclusively support the need for systemic antibiotic therapy in cases of immediate implantation into chronically infected sockets [35]. The absence of controlled trials demonstrating the clinical effectiveness of a specific treatment protocol has contributed to this uncertainty. A systematic review of 366 studies that assessed immediate implant placement found only eight studies eligible for inclusion in the final analysis. The results revealed that the survival rate of immediately placed implants without concomitant antibiotic therapy was slightly lower than when antibiotics were used (risk ratio 0.93) [36]. However, bone grafting, together with immediate implantation, is a greater risk factor as surgical wound complications after immediate implantation occur almost five times more frequently with IIP requiring bone grafting compared with implant placement in edentulous ridges without the need for bone grafting (26% versus 5%) [37].
Figure 11.6 In cases of failed endodontic treatment, mechanical debridement can be followed by irrigation with diluted hydrogen peroxide. The solution is left in the socket for 20–30 seconds to allow for the release and activity of free oxygen radicals that help eliminate the infection. Afterwards, the socket is rinsed several times with saline.
Table 11.2 Recommended dosage for prophylactic systemic antibiotic therapy for immediate implant placement.
| Antibiotic | Preoperative prophylaxis loading dose (1 hour before surgery) | Postoperative maintenance dose |
|---|---|---|
| Amoxicillina | 2–3 g | 500 mg/8‐hourly |
| Clindamycin | 600 mg | 150‐ or 300 mg/6‐hourly |
| Azithromycin | 500 mg | 250 mg/24‐hourly |
| Clarithromycin | 500 mg | 250 mg/12‐hourly |
| Metronidazole | 1 g | 500 mg/6‐hourly |
a Amoxicillin is the preferred choice, but patients with a penicillin allergy can receive alternative antibiotics as a substitute.
The lack of a standardized protocol for the timing, type, dosage, and duration of antibiotic therapy is another issue. Table 11.2 shows the antibiotic regimens used in some published clinical trials. Penicillin allergy is reported by approximately 10–20% of patients, meaning that various antibiotics are used as alternatives to amoxicillin. One clinical study indicated that immediately placed implants in patients who received amoxicillin prophylaxis had early failure in 6 of 630 cases (1%). In contrast, this rate was 6 of 57 cases (approximately 10%) where clindamycin was used, due to self‐reported penicillin allergy [38]. Either clindamycin does not provide adequate antibiotic coverage or it may impede the peri‐implant bone healing process. Thus, prescribing clindamycin is not recommended. The duration of antibiotic therapy, administering antibiotics as a single dose before treatment may not offer adequate protection. Therefore, continuing treatment for 5–7 days following surgery may help prevent infection and its negative impact on osseointegration. The European Society of Endodontology advocates for antibiotic administration in the form of an initial loading dose followed by maintenance doses for endodontic infections [22].
Assessment of Treatment Success
Immediate implant placement is a popular treatment option among both clinicians and patients as it reduces the overall duration of treatment, number of surgical interventions, and duration of edentulism. In general, tooth sockets can be divided into two categories: intact and compromised. Reviewing the literature reveals that comparable survival rates may be achieved for immediate implant placement in both intact and compromised sockets. However, it is important to approach such data with caution since there are few well‐controlled clinical trials with long‐term follow‐ups on this topic [22]. As a result, the existing data are insufficient to develop a comprehensive, efficient, and safe treatment protocol for immediate implant placement.
Complications
Residual apical infection left after tooth extraction can sometimes lead to retrograde peri‐implantitis (Figure 11.7a–g) [39]. As well, implant placement at 9–16 weeks post extraction of teeth removed due to failed endodontics without adequate debridement can result in retrograde peri‐implantitis due to biofilm persistence in necrotic bone (Figure 11.8).
Conclusions
Placing immediate implants in chronically infected tooth sockets is not an arbitrary contradiction. Even if the infection has caused considerable destruction of the alveolus, provided that the IIP can be adequately stabilized in a prosthetically favorable location, treatment may proceed. Following meticulous removal of all infected granulation tissue and removal of sclerotic apical bone, various grafting procedures can be used to reconstruct lost hard and soft tissues. If bone grafting is included, serious consideration should be given to including an appropriate systemic antibiotic regimen.
Figure 11.7 (a) Following immediate implant placement, a retrograde peri‐implantitis was observed at the right lateral incisor 2 years after treatment. (b) A vestibular flap was raised. (c) The peri‐implantitis infection was debrided with curettes. (d) A rotary titanium brush was used finalize the debridement. (e) After chemical and saline irrigations, the defect was grafted with particulate xenograft. (f) A collagen barrier covered the graft. (g) The flap was closed.
Figure 11.8 (a) Immediate implantation was used to replace the patient’s lateral incisor and canine teeth both with existing periapical lesions. (b) The patient presented with pain and fistula formation 2 months following surgery, and an orthopanthomograph suggested persistent infection. (c) Infection was confirmed using cone beam computed tomography.
Source: Courtesy of Dr. Fatemeh Abbasipour.
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