An update on the prevention and treatment of peri-implant diseases

Managing peri-implant diseases, which are linked to considerable morbidity, poses significant challenges. The latest clinical practice guidelines¹ seek to identify optimal interventions for maintaining peri-implant tissue health, aiming to prolong the complication-free survival of dental implants used in tooth replacement. Peri-implant diseases, driven by peri-implant biofilms, manifest as inflammatory conditions affecting peri-implant tissues, with two distinct conditions: peri-implant mucositis and peri-implantitis. Peri-implant diseases, especially peri-implantitis, present a growing public health concern owing to their rising prevalence and adverse outcomes, such as implant and prosthesis loss, leading to substantial dental care costs and have an overall economic impact.

Peri-implant mucositis, as defined by Heitz-Mayfield and Salvi,² is an inflammatory condition affecting the peri-implant mucosa without concurrent marginal bone loss. Clinically, it manifests as bleeding upon gentle probing, accompanied by potential signs of inflammation, such as erythema, swelling and/or suppuration. The condition is associated with increased probing depth, attributed to oedema or diminished probing resistance. Disruption of host-microbial homeostasis at the implant–mucosa interface is the underlying cause, making it a reversible condition when assessed through host biomarkers. Contributing factors include biofilm accumulation, smoking, and radiation therapy.³

In contrast, peri-implantitis is identified as a pathological condition linked to peri-implant biofilms, presenting in tissues surrounding dental implants and characterized by inflammation in the peri-implant mucosa and progressive loss of supporting bone. Clinical signs at peri-implantitis sites include inflammation, bleeding on probing (BOP), suppuration, increased probing depths (PDs), and/or recession of the mucosal margin. Radiographic evidence reveals bone loss compared to previous examinations.³

The primary causative factor in the initiation and progression of peri-implantitis is the accumulation of a biofilm on the implant surface. Notable risk factors encompass a history of severe periodontitis, insufficient plaque control, the absence of consistent post-implant therapy supportive care (SPIC), the presence of submucosal cement post-prosthetic restoration, or implant positioning impeding oral hygiene, the lack of peri-implant keratinized mucosa (PIKM), occlusal overload, as well as systemic risk factors, including smoking and diabetes. Other factors including the presence of titanium particles in peri-implant tissues, bone compression necrosis, overheating, micromotion, or biocorrosion have been documented;⁴ however, further research is required to precisely define their roles.⁴

This review outlines the case definitions and diagnoses for peri-mucositis and peri-implantitis as per the 2017 WWP classification and summarizes the EFP S3-level clinical practice guidelines.³

Periodontitis versus peri-implantitis

Researchers have looked into the pathophysiology of peri-implant diseases by drawing parallels with periodontal diseases. Analogies between peri-implant mucositis and biofilm-induced gingivitis, as well as between peri-implantitis and periodontitis, have been explored. It is important to note that peri-implant tissues differ from periodontal tissues, lacking cementum and a periodontal ligament, comprising only alveolar bone and peri-implant mucosa.

Distinct characteristics of the peri-implant mucosa include a longer epithelial attachment, the absence of connective tissue fibres in the supra-crestal area, and reduced vascularization. Robust evidence from both animal and human studies supports peri-implant biofilms as the primary aetiological factor for peri-implant mucositis.³ These biofilms develop on hard, non-shedding surfaces, mirroring the formation of dental plaque biofilms on natural teeth.^5,6 Histologically, peri-implant mucositis mirrors gingivitis, presenting as a well-defined inflammatory lesion adjacent to the junctional/pocket epithelium. It is richly infiltrated by vascular structures, plasma cells and lymphocytes, but does not extend apically to the junctional/pocket epithelium or into the supra-crestal area.^2,3

As with gingivitis, evidence exists to support the contention that peri-implant mucositis is treatable, and can be successfully managed by careful control of the peri-implant biofilm. However, if allowed to persist, peri-implantitis develops, as peri-implantitis is always preceded by peri-mucositis.^2,3

The primary cause of peri-implantitis is the accumulation of peri-implant biofilm, evidenced by human observational studies linking poor biofilm control and non-adherence to maintenance care to an increased risk of incident peri-implantitis.³ Peri-implantitis lesions are larger and usually circumferential, compared to peri-implant mucositis or periodontitis, with higher proportions of neutrophils and B cells, resembling immune-inflammatory infiltrates seen in periodontitis. The specific bacteria or pro-inflammatory cytokine profiles associated with these distinctive histological features are yet to be conclusively determined.^3,4,7

Prevalence of peri-implantitis and peri-mucositis

A systematic review conducted during the XI European Workshop in Periodontology in 2014 revealed a patient-level prevalence estimate of 43% for peri-implant mucositis and 22% for peri-implantitis.⁸ Another review, incorporating 47 studies, reported a prevalence of 46.8% for peri-implant mucositis and 19.8% for peri-implantitis.⁹ A more recent study showed that the prevalence of peri-implantitis was 19.5% at the patient level and 12.5% at the implant level, and it remains highly variable even following restriction to the clinical case definition.¹⁰ Perhaps we should only be using the definition proposed in the 2017 World Workshop on the classification of periodontal and peri-implant diseases and conditions (Table 1).

Peri-implant mucositis, if promptly addressed, can be successfully treated; however, neglected cases may progress to peri-implantitis, a condition believed to follow a non-linear accelerating pattern, advancing more rapidly than typical periodontitis lesions.^3,4 The progression of peri-implantitis is likely to result in the eventual loss of the affected implant and the implant-supported prosthesis. While the impact of peri-implant diseases on quality of life is not extensively documented, one study found no discernible impact on oral health-related quality of life for either peri-implantitis or its surgical treatment.¹¹

The S3-level guideline

The guideline seeks to establish optimal interventions for preserving peri-implant tissue health, enhancing the long-term success of dental implants in replacing missing teeth. It provides evidence-based recommendations for the prevention and treatment of peri-implant diseases, intending to improve the quality of interventions globally. The objectives include enhancing preventive and therapeutic approaches, reducing dental implant loss from peri-implantitis, and, ultimately, minimizing medical and dental costs while enhancing patient quality of life. Developed by the European Federation of Periodontology (EFP), it relies on 12 systematic reviews to support its development.¹ The guideline categorizes interventions based on distinct stages of peri-implant tissue management, aligning with various phases of implant therapy:

• Patients awaiting dental implant rehabilitation (pre-operative);
• Patients undergoing dental implant rehabilitation (peri-operative);
• Patients with existing dental implant/s (post-operative).

Diagnosis of peri-implant diseases

Successful implant-supported rehabilitation requires regular assessment to facilitate early diagnosis of peri-implant diseases. This is evident in the case definitions for peri-implant health, peri-implant mucositis, and peri-implantitis established by the 2018 World Workshop on the Classification of Periodontal and Peri-Implant Diseases and Conditions (Table 2).^{2–4,12–14}

Specific care pathways according to diagnosis of peri-implant condition

It is important to correctly diagnose peri-implantitis and peri-implant mucositis because they are treated differently. Peri-implant mucositis is treatable and can be prevented by taking the same steps as those used to prevent peri-implant diseases in general. Treating peri-implant mucositis is also the best way to prevent peri-implantitis. The goal of the S3-level guidelines is to keep dental implants and the prostheses they support healthy and functioning by preventing and treating peri-implantitis.¹ However, once peri-implantitis has developed, it is not possible to fully restore the tissue around the implant, even if the inflammation is controlled.

Pre-operative interventions

Owing to the high prevalence of peri-implant diseases, any patient receiving dental implants should be considered at risk of developing some form of peri-implant disease. Upon exposure of the dental implant/abutment complex to the oral environment and subsequent prosthetic loading, biofilm accumulation can trigger inflammation, potentially causing peri-implant diseases. Hence, preventive measures should begin during treatment planning and persist through implant placement and prosthetic rehabilitation. Pre-operative interventions must address established risk factors, including smoking, diabetes, untreated periodontitis and inadequate oral hygiene practices, to mitigate peri-implant disease development. Primordial prevention essentially aims to prevent the establishment of risk factors rather than addressing them after they have developed. Interventions for primordial prevention are for patients awaiting dental implant rehabilitation and therefore, before implant placement. The interventions include improving glycaemic control in people with diabetes, educating the patient about the importance of their adherence to SPIC (supportive peri-implant care) visits and home care, provision of regular supportive care, cessation of cigarette smoking (including e-cigarettes), improved oral hygiene and reducing bruxing/parafunctional habits and periodontal therapy to eliminate gingivitis and achieve periodontal stability (Table 3).

Peri-operative interventions

This includes interventions before dental implant placement that are carried out during surgical implant placement and during implant-supported prosthesis design/preparation/placement. Scientific literature highlights the common occurrence of ‘dental implants placed under less-than-ideal circumstances’ in routine dental practice, potentially leading to an increased prevalence of peri-implantitis.^3,4 Prosthetic factors are also identified as contributors to the risk of peri-implant disease onset and progression.⁴ The 2017 Workshop on the classification of periodontal and peri-implant diseases acknowledged limited evidence linking peri-implantitis to factors such as post-restorative submucosal cement presence and poorly positioned implants hindering oral hygiene and maintenance.³

In light of these findings, preventing peri-implant diseases should be a focal point for the following (Table 4):

• Implant treatment planning, ensuring prosthetically driven implant placement, and addressing local factors that may hinder ideal placement;
• Designing and installing prosthetic reconstructions, considering local risk factors that may impede oral hygiene access or, if feasible, opting for screw-retained, rather than cement-retained restorations.

Post-operative interventions

Following the exposure of dental implants to the oral environment and the loading of prosthetic restorations, the management of peri-implant tissues should be guided by their clinical condition. Given the high reported incidence of peri-implant diseases, patients should promptly enroll in a supportive peri-implant care (SPIC) programme. SPIC programmes should incorporate primary prevention interventions, such as professional removal of supra- and subgingival plaque biofilm, oral hygiene motivation and coaching, and early detection of pathological conditions.

For a summary for interventions to follow please see Table 5, which is adapted from the S3-level guidelines.¹

Treatment for peri-mucositis

Interventions for the management of peri-implant mucositis focus on the control of biofilm, which can be self-administered or professionally delivered. Treatment outcomes should be evaluated after 2–3 months, and re-treatment is recommended if the relevant endpoints have not been achieved. These endpoints reflect the re-establishment of peri-implant health, which is essentially identical to the primary prevention of peri-implant diseases and the secondary prevention of peri-implant mucositis. Furthermore, since the treatment of peri-implant mucositis is central to the prevention of the onset of peri-implantitis,¹⁵ this treatment is in fact the most important preventive intervention for peri-implantitis and, as such, represents the main component of professional interventions during SPIC (Table 6).

Treatment for peri-implantitis

Managing peri-implantitis is a relatively recent focus in research and clinical practice. While there are key distinctions between peri-implantitis and periodontitis, the treatment foundation for peri-implantitis draws from successful periodontitis approaches. Hence, adopting a stepwise approach, akin to periodontal therapy,¹⁴ aligns with proposed interventions for periodontitis.

The primary aim of the non-surgical phase in peri-implantitis treatment is to regulate peri-implant biofilms and inflammation, emphasizing sub-marginal instrumentation. Additionally, interventions targeting supramarginal biofilm control and risk factor management are integral to this phase. Following treatment, it is crucial to monitor progress in inflammation and suppuration control, reassessing outcomes. While clear endpoints for therapy have been established in periodontitis treatment, evidence supporting the success of steps 1 and 2 in peri-implantitis treatment is limited.¹⁶

Upon confirming a diagnosis of peri-implantitis, it is imperative to acknowledge two key points:

• Peri-implantitis is an irreversible condition; thus, even successful peri-implantitis therapy results in the assignment of a ‘stable’ peri-implantitis diagnosis to the particular implant;
• The outcomes of peri-implantitis treatment are contingent upon various factors, including implant fixture and prosthetic characteristics, mucogingival factors, other patient factors, local conditions, disease severity, and bone defect configuration. Consequently, tailored interventions addressing one or several of these factors are employed in its management, as documented in systematic reviews. The effectiveness of these interventions exhibits variability in treatment outcomes.

According to the following care pathways, peri-implantitis management should involve the following sequential steps (Figure 1):

• Upon diagnosis, determine whether the affected implant is treatable;
• If treatable, initiate non-surgical therapy, involving submarginal instrumentation;
• After non-surgical therapy, reassess clinical outcomes based on predetermined success criteria. If the success criteria are met, enroll the patient in a SPIC programme. If the success criteria are not met, and the implant is still deemed maintainable, proceed with the surgical step.
• The surgical phase of peri-implantitis treatment must always include submarginal instrumentation after raising a surgical flap. Additional implant surface decontamination with titanium brushes may be considered.
• After surgery, evaluate clinical outcomes and ensure compliance with predefined success criteria. If the success criteria are met, enroll the patient in a secondary prevention SPIC programme. If the success criteria are not met, and the implant is still deemed maintainable, recommend re-treatment of the implant.

Non-surgical management of peri-implantitis

EFP recommends prioritizing implant/prosthesis retention in peri-implantitis treatment, starting with a non-surgical step, followed by re-evaluation.

In the non-surgical step of peri-implantitis treatment, the recommended interventions include (Table 7):

• Oral hygiene instructions and motivation;
• Risk-factor control;
• Prosthesis cleaning/removal/modification, addressing biofilm retentive factors and evaluating prosthesis components when necessary and feasible;
• Supramarginal and sub-marginal instrumentation;
• Concomitant periodontal therapy as needed;
• The endpoints of successful non-surgical therapy of peri-implantitis, assessed 6–12 weeks after therapy. At the implant level: PD ≤5mm, and no BOP at more than one point, and no suppuration Additional treatment including re-instrumentation, surgical intervention or supportive Peri-Implant Care (SPIC) may be recommended if the above endpoints are not achieved.

Surgical management of peri-implantitis

The surgical approach in peri-implantitis management aims to enhance access to the implant for effective surface decontamination, ultimately resolving the inflammatory lesion. Surgical intervention targets sites displaying persistent pathology after non-surgical therapy, specifically deep pockets with bleeding on probing or suppuration. A typical surgical procedure involves flap elevation, removal of inflamed tissue, and implant surface cleaning/decontamination, typically employing saline-soaked gauze and curettes for mineralized deposit removal. Additional procedures may encompass managing peri-implant osseous defects through reconstructive approaches for intra-osseous defects ≥3 mm, and employing alternative techniques for implant surface decontamination, such as the use of titanium brushes.

Currently, there is insufficient evidence for the use of local antibiotics as adjuncts in the surgical management of peri-implantitis.¹ Additionally, the S3 guidelines do not recommend the use of systemic antibiotics in the surgical treatment of peri-implantitis.

Effective self-performed oral hygiene is crucial for successful surgical peri-implantitis treatment. Surgery is not advised for patients unable to maintain satisfactory oral hygiene independently. Treatment success hinges on the patient's consistent commitment to proper oral care practices.

It is recommended that dental teams offering implant therapy also possess the professional expertise to manage peri-implantitis. Since surgical treatment of peri-implantitis is complex, it is recommended that the surgery is provided by dentists with specific training or by specialists.

Endpoints for successful surgical therapy of peri-implantitis (Table 8):

• At implant level: ≤1 point of bleeding on probing, absence of suppuration on probing, PD ≤5 mm, and no progressive bone loss compared to pre-treatment levels;
• Recommended timeline: record clinical parameters 6 months post-treatment, with radiographs at 12 months;
• Long-term evaluation criteria: include complication-free survival of the implant and implant-supported prosthesis, along with patient satisfaction (e.g. aesthetic appreciation).

Conclusion and key messages

Appropriate interventions for the preservation and/or restoration of peri-implant tissue health should be considered before, during and after the placement of dental implants. Risk-factor assessment and control, as well as the diagnosis and monitoring of the health/disease status of the peri-implant tissues, are essential in selecting the appropriate care pathway for each patient. Successful, long-term maintenance of peri-implant tissue health encompasses behavioural modification, health monitoring, appropriate preventive interventions, and, when necessary, careful treatment planning and execution.

Peri-implant tissue health, peri-implant mucositis, and peri-implantitis form a continuum, with changes driven by inflammation following microbial biofilm accumulation. Controlling inflammation through the removal of plaque biofilm is key to the preservation of health, and prevention and treatment of peri-implant diseases.

Preventive and treatment interventions are organized into specific needs-based care pathways. Prevention aims to achieve and maintain peri-implant tissues and thus promote peri-implant health. This is achieved by enabling adequate self-performed and professionally delivered oral hygiene measures, which need to be customized according to the design of implant-supported restorations.

SPIC is an essential component in the management of peri-implant diseases. It is critical for preserving peri-implant tissue health and preventing disease onset, and must be offered to every patient who receives dental implants.

The aim of SPIC is to arrest the inflammatory processes within the peri-implant tissues and to control local and systemic risk factors that may perpetuate them. Disruption of the locally accumulating microbial biofilms is a key target.

Treatment of peri-implant mucositis is considered a key strategy in preventing the onset of peri-implantitis. Treatment of peri-implantitis is performed sequentially, and encompasses an initial non-surgical step, followed by a surgical step, depending on the outcomes of the initial treatment. SPIC should always be instituted, particularly upon completion of peri-implantitis treatment.

In conclusion, adopting a step-wise and minimally invasive approach is paramount in the management of peri-implant diseases. Emphasizing good oral hygiene practices, prioritizing the preservation and restoration of peri-implant health whenever feasible, and diligently identifying and mitigating risks before, during and after implant placement are key principles for successful outcomes. By incorporating these strategies, clinicians can enhance patient care and contribute to the long-term success and health of dental implants.