Failures in periodontal therapy

Introduction

Periodontal therapy refers to the comprehensive treatment aimed at preventing, managing, and reversing periodontal disease, which affects the supporting structures of the teeth, including the gums, periodontal ligament, and alveolar bone. The primary goal of periodontal therapy is to halt the progression of disease, prevent tooth loss, and restore the health and function of the periodontium. The success of periodontal therapy is often measured by clinical parameters such as pocket depth reduction, clinical attachment level (CAL) gain, and reduction of inflammation. Long-term tooth retention and stabilization of periodontal tissues are also critical indicators of success. However, periodontal therapy is not without challenges. The presence of deep pockets, furcation involvements, and non-compliance with maintenance can lead to treatment failure and disease recurrence. In the following discussion we shall read in detail about various factors responsible for the failure of periodontal treatment.

Parameters of success of periodontal therapy

The parameters of success in periodontal therapy are crucial for assessing the effectiveness of treatment, preventing disease progression, and ensuring long-term stability of periodontal health (Reference available in book). These parameters are based on clinical, radiographic, and patient-reported outcomes and are essential in determining whether the therapy has met its objectives. Following are the parameters which determine the success of periodontal therapy,

Reduction in probing pocket depth (PPD)

Probing pocket depth refers to the depth of the space between the tooth and the surrounding gingival tissue, measured with a periodontal probe. Successful therapy typically results in a reduction of pocket depths to less than 4 mm in most sites, indicating a decrease in inflammation and the reattachment of periodontal tissues (Reference available in book). Deeper pockets (>6 mm) are more prone to disease recurrence, and achieving a stable reduction is key to preventing further progression.

Clinical attachment level (CAL) gain

Clinical attachment level measures the position of the periodontal attachment in relation to a fixed point on the tooth, typically the cementoenamel junction (CEJ). A successful outcome is defined by a gain in clinical attachment, indicating that the periodontal tissues have healed and reattached following treatment. An increase in CAL is particularly important in regenerative therapies, where the goal is to restore the lost attachment.

Bleeding on probing (BOP)

Bleeding on probing is a key indicator of inflammation in the periodontal tissues. The absence of BOP after therapy is considered a reliable marker of periodontal health and indicates a successful resolution of inflammation. Persistent BOP after treatment suggests the presence of ongoing inflammation or incomplete disease control.

Radiographic evidence of bone regeneration

In cases of periodontal bone loss, radiographs are used to assess changes in alveolar bone levels. Successful therapy may result in bone regeneration, particularly following regenerative procedures like bone grafts or guided tissue regeneration (GTR). Stabilization of bone levels and the absence of further bone loss are also indicators of a positive outcome (Reference available in book).

Stability of tooth mobility

Tooth mobility is often associated with periodontal bone loss and tissue destruction. A reduction in tooth mobility following treatment indicates improved periodontal support and is an essential factor in the long-term stability of the tooth. Successful therapy should aim to stabilize or reduce excessive mobility, especially in compromised teeth.

Absence of suppuration

Suppuration or pus discharge from periodontal pockets indicates active infection and tissue destruction. The absence of suppuration is a positive sign of infection control and tissue healing after therapy.

Patient comfort and absence of symptoms

Periodontal therapy should aim to alleviate patient symptoms such as pain, discomfort, and gingival swelling. Successful outcomes are marked by the patient reporting an absence of pain, gingival bleeding, and improvement in oral function (e.g., chewing and speaking). Patient satisfaction and quality of life improvements are increasingly recognized as important parameters of success.

Long-term tooth retention

A fundamental goal of periodontal therapy is to preserve natural teeth. Long-term tooth retention, especially in periodontally compromised patients, is a critical measure of therapeutic success. Teeth that remain functional and stable without the need for extraction due to periodontal reasons are indicators of successful therapy.

Improvement in plaque control

Successful therapy should lead to improved oral hygiene practices and better plaque control, as evidenced by the reduction in plaque scores during follow-up assessments. Plaque is a major etiological factor in periodontal disease, and its control is essential for preventing recurrence.

Reduction or absence of gingival recession

In some cases, periodontal therapy can lead to gingival recession due to shrinkage of inflamed tissues. While some degree of recession may occur, minimizing it or avoiding further recession is considered a success. Tissue stability without further recession post-therapy indicates a favorable outcome.

Lack of disease recurrence

Periodontal maintenance is crucial for preventing the recurrence of disease. Successful therapy is demonstrated by stable periodontal conditions during follow-up visits with no new sites of inflammation, attachment loss, or pocket formation. Recurrence of disease indicates failure in maintaining long-term success.

Successful outcome of regenerative procedures

For regenerative treatments, such as bone grafting or guided tissue regeneration (GTR), the success parameters include evidence of new bone formation and periodontal ligament regeneration and clinical stability of regenerated tissues without signs of relapse or breakdown.

Patient compliance and cooperation

Although not a direct clinical parameter, patient adherence to recommended oral hygiene practices and follow-up visits is critical to the success of periodontal therapy. High levels of patient compliance with home care and maintenance protocols are associated with better long-term outcomes.

Definition of treatment failure in periodontal therapy

Treatment failure in periodontal therapy refers to the inability of therapeutic interventions; whether surgical, non-surgical, or regenerative, to achieve or maintain the desired clinical outcomes. These outcomes typically include pocket depth reduction, clinical attachment gain, inflammation resolution, and long-term stability of the periodontium. Treatment failure may be partial, with some goals unmet, or complete, where disease progression continues, leading to further periodontal destruction and possibly tooth loss. There are multiple clinical signs and symptoms of failure of periodontal treatment. Failure to reduce pocket depths to a manageable level (typically ≤ 4 mm) despite therapy indicates ongoing disease activity and risk for future periodontal breakdown. Persistent deep pockets (≥ 5-6 mm) are a key indicator of unsuccessful therapy, as they harbor anaerobic bacteria that perpetuate inflammation. Failure to achieve clinical attachment level (CAL) gain (a primary marker of tissue reattachment) is indicative of treatment failure, especially after regenerative or surgical procedures aimed at tissue regeneration (Reference available in book). Persistent bleeding on probing (BOP) is a sign of unresolved inflammation in the periodontal tissues, suggesting inadequate infection control and potential for further tissue destruction. Ongoing pus discharge from periodontal pockets is a clinical sign of infection, indicating that the disease is still active despite therapy (Reference available in book).

Radiographic evidence of continued bone loss post-therapy signals treatment failure, particularly in cases of regenerative surgery where bone growth was the intended outcome. Recurrence of periodontitis after initial stabilization suggests treatment failure, often due to inadequate long-term maintenance or poor patient compliance. Recurrent disease may manifest as new pocket formation, bone loss, and clinical attachment loss. The ultimate failure in periodontal therapy is tooth loss, which may result from untreated or unresolved periodontal disease, despite therapeutic efforts to preserve the tooth (Reference available in book).

Clinical implications of periodontal treatment failure

The implications of periodontal treatment failure are significant for both oral and systemic health. Treatment failure often leads to the progression of periodontitis, characterized by deeper periodontal pockets, further attachment loss, and increased bone resorption. If left untreated, advanced periodontal disease can lead to severe periodontal breakdown, requiring more invasive surgical interventions or leading to tooth extraction. One of the most serious outcomes of untreated or poorly managed periodontal disease is tooth loss. Teeth with severe attachment loss, mobility, and persistent inflammation may become non-restorable, necessitating extraction. Edentulism can significantly impact a patient’s ability to chew, speak, and maintain proper nutrition, leading to diminished quality of life.

Periodontal treatment failure may lead to gingival recession, increased tooth mobility, and loss of bone support, which can compromise both function and aesthetics. Aesthetic concerns such as exposed roots, elongated teeth, or uneven gingival contours can affect the patient’s confidence and quality of life. Along with this, chronic inflammation resulting from unresolved periodontal disease has been linked to systemic conditions such as cardiovascular disease, diabetes, and adverse pregnancy outcomes (Reference available in book). Treatment failure, therefore, poses risks beyond the oral cavity. Inflammatory mediators from periodontitis, such as cytokines and prostaglandins, can contribute to systemic inflammation, exacerbating conditions like diabetes and atherosclerosis.

Factors contributing to periodontal treatment failure

Several factors can contribute to the failure of periodontal therapy, ranging from patient-related issues to systemic conditions and treatment inadequacies. Understanding these factors is crucial for clinicians to minimize treatment failures and improve long-term outcomes. Below are the major factors contributing to periodontal treatment failure:

Poor patient compliance

One of the most significant factors in treatment failure is poor patient compliance with oral hygiene instructions. Effective plaque control is essential for the success of both non-surgical and surgical periodontal therapy. Failure to maintain proper oral hygiene can lead to plaque accumulation, gingival inflammation, and recurrence of disease. Along with this, patients who do not adhere to recommended periodontal maintenance intervals (every 3-6 months) are at higher risk of disease recurrence. Regular maintenance visits allow for early detection of any disease relapse and help in reinforcing oral hygiene practices (Reference available in book).

Smoking

Smoking is one of the most critical risk factors for periodontal disease progression and treatment failure. Smokers have reduced healing capacity, increased susceptibility to infections, and a poorer response to both non-surgical and surgical therapy. Smoking impairs the body’s immune response and reduces blood flow to the gingival tissues, which compromises healing and tissue regeneration.

Systemic health conditions

Poorly controlled diabetes negatively affects periodontal health and contributes to treatment failure. Diabetic patients experience delayed wound healing, increased inflammation, and higher susceptibility to infection, making it harder to achieve successful treatment outcomes. Conditions like osteoporosis may reduce the density of alveolar bone, making it more susceptible to resorption and periodontitis. This can hinder the success of regenerative procedures like bone grafting. Patients with compromised immune systems, such as those undergoing cancer treatment or living with HIV, may experience poor healing and an increased risk of periodontal disease progression (Reference available in book).

Inadequate initial therapy

Suboptimal Debridement: Inadequate removal of plaque and calculus during scaling and root planing (SRP) or during surgical procedures can leave bacterial deposits that continue to stimulate inflammation and disease progression (Reference available in book). If deeper pockets are not adequately addressed, particularly in furcation areas or where access is difficult, the persistence of these pockets can lead to recurrent disease. Over-reliance on systemic or local antibiotics without proper mechanical debridement may result in temporary improvement, but disease recurrence is likely once the antibiotics are discontinued (Reference available in book).

Ineffective surgical techniques

Poor surgical technique, including improper flap design or tissue management during periodontal surgery, can result in poor wound healing, excessive gingival recession, or incomplete pocket reduction. Regenerative procedures such as guided tissue regeneration (GTR) or bone grafting may fail if the materials used are suboptimal, if the defect morphology is unfavorable, or if the patient’s biology does not support regeneration. If post-operative care is inadequate and inflammation is not well controlled, surgical results may deteriorate.

Presence of un-modifiable risk factors

Some patients have a genetic predisposition to aggressive forms of periodontitis, making them more susceptible to disease progression despite appropriate therapy. Certain anatomical factors, such as deep pockets, furcation involvement, and bone morphology, make it difficult to completely eliminate the periodontal infection. These factors increase the likelihood of treatment failure, especially in cases of advanced periodontal destruction (Reference available in book).

Inaccurate diagnosis and treatment planning

Failure to properly diagnose the type and extent of periodontal disease can result in inappropriate treatment strategies. For example, treating aggressive periodontitis with only non-surgical measures can lead to treatment failure, as more aggressive interventions may be required. Not taking systemic health conditions into account during treatment planning can lead to suboptimal outcomes. For example, failure to manage diabetes during periodontal therapy can result in poor healing and disease progression.

Incomplete control of local factors

Leftover calculus deposits on root surfaces can serve as a nidus for bacterial plaque, perpetuating inflammation and attachment loss even after therapy. Poorly contoured restorations or malocclusions can create areas of plaque stagnation, increasing the risk of treatment failure. These local factors must be corrected to ensure successful periodontal therapy (Reference available in book). Teeth with furcation involvements (where the roots of molars diverge) are particularly challenging to treat, as they are harder to clean and maintain. Persistent pockets in these areas often lead to treatment failure.

Psychosocial factors

Psychological stress has been shown to negatively affect the immune system, impairing the body’s ability to fight periodontal infections and heal after treatment. Patients with depression or other mental health conditions may struggle with maintaining oral hygiene or attending regular dental appointments, increasing the risk of periodontal treatment failure.

Sub-optimal healing responses

Some patients exhibit a hyperactive immune response, resulting in exaggerated inflammation and tissue destruction even after successful removal of local irritants. Such overreactions can hinder tissue healing and lead to recurrence of disease. Patients with conditions that impair wound healing, such as vascular diseases or those on medications like corticosteroids, may experience slower or incomplete healing after therapy, leading to poorer outcomes (Reference available in book).

Re-infection or contamination

If plaque control is insufficient, periodontal pockets may become re-infected by pathogenic bacteria, leading to disease recurrence. This can occur in cases where patients fail to maintain adequate home care after therapy or where systemic antibiotic therapy is not coupled with mechanical cleaning. Periodontal pathogens from untreated areas of the mouth or other dental structures can reinfect previously treated areas, contributing to treatment failure.

Financial constraints

Periodontal therapy, especially surgical and regenerative procedures, can be costly. Patients may be unable to afford the complete range of treatments needed for optimal results, opting instead for limited or inadequate interventions, which increases the likelihood of treatment failure. Financial constraints may also prevent patients from attending regular periodontal maintenance visits, which are crucial for the long-term success of therapy.

Evidence-based approach to periodontal failures

An evidence-based approach to addressing periodontal failures involves utilizing the best available scientific research, clinical expertise, and patient values to diagnose, manage, and mitigate the factors contributing to unsuccessful periodontal therapy. By incorporating high-quality evidence from clinical trials, systematic reviews, and guidelines, clinicians can improve the chances of treatment success and reduce the recurrence of periodontal disease. The key components of an evidence-based approach to periodontal failures include the following,

Risk assessment and diagnosis

A thorough risk assessment and accurate diagnosis form the foundation of effective periodontal treatment. Identifying the patient’s risk factors such as systemic diseases, smoking, and poor oral hygiene is crucial in tailoring an evidence-based treatment plan. Periodontal charting, radiographic analysis, and microbial testing help identify the extent and nature of the disease. Tools like the Periodontal Risk Assessment (PRA) or Risk Calculator are designed to predict treatment outcomes and assess the likelihood of disease recurrence based on individual risk factors. Clinicians must evaluate systemic factors (e.g., diabetes, smoking, immune disorders) that can affect periodontal therapy success. Studies show that poorly controlled diabetes and smoking significantly reduce the success of periodontal treatment (Reference available in book).

Non-surgical periodontal therapy (NSPT)

Non-surgical periodontal therapy, such as scaling and root planing (SRP), is the first line of treatment in periodontal disease. Clinical trials show that SRP alone is often sufficient in reducing probing pocket depths (PPD) and improving clinical attachment levels (CAL) in cases of mild to moderate periodontitis. For cases where non-surgical therapy is inadequate, adjunctive antimicrobial treatments, such as local delivery of antibiotics or systemic antibiotics, may be used to improve outcomes (Reference available in book). However, their use should be limited to specific cases, as overuse can lead to antibiotic resistance. Laser-assisted periodontal therapy has shown some promising results in improving healing outcomes by promoting debridement and reducing bacterial load. However, the evidence remains mixed, and its effectiveness depends on proper case selection.

Surgical periodontal therapy (SPT)

For patients who fail to respond to non-surgical treatments, evidence-based guidelines recommend surgical interventions, which are more invasive but can offer more definitive results. Surgical approaches such as flap surgery, bone grafting, and guided tissue regeneration (GTR) are commonly employed to address deeper periodontal pockets, bone loss, and gingival recession. Evidence supports the use of these techniques, particularly in regenerative therapy, for achieving long-term clinical attachment gain and reducing pocket depths. Studies have shown that the use of biologic agents like enamel matrix derivatives (EMD), platelet-rich plasma (PRP), or growth factors can enhance healing and regeneration when used alongside surgical interventions (Reference available in book). Open-flap surgery is often used to access deep periodontal pockets and ensure complete debridement. Clinical studies demonstrate the effectiveness of flap surgery in reducing probing depths and improving periodontal stability.

Regenerative therapy

Regenerative procedures aim to restore lost periodontal structures, including bone, cementum, and periodontal ligament. Bone grafts and barrier membranes are used in regenerative surgery to promote bone formation and guide tissue regeneration. Meta-analyses indicate that guided bone regeneration (GBR) and GTR result in greater bone fill and clinical attachment gain compared to non-surgical methods. Systematic reviews confirm that guided tissue regeneration (GTR) is highly effective in regenerating periodontal structures, especially in intrabony defects, furcation defects, and recession defects (Reference available in book). The use of bioactive materials (e.g., EMD) enhances these results.

Management of refractory periodontitis

Refractory periodontitis refers to cases where the disease continues to progress despite thorough and appropriate periodontal treatment. Recent evidence suggests that microbial testing and host modulation therapy can help identify patients at risk of refractory periodontitis. Sub-antimicrobial doses of doxycycline (SDD) and nonsteroidal anti-inflammatory drugs (NSAIDs) may help manage inflammation in these cases. Although systemic antibiotics are not recommended as a routine part of periodontal therapy, evidence supports their use in cases of refractory or aggressive periodontitis when specific bacterial pathogens are involved.

Maintenance therapy

An essential component of an evidence-based periodontal care plan is periodontal maintenance therapy (PMT), which helps prevent disease recurrence and prolong the success of the initial therapy. Clinical evidence supports the importance of periodontal maintenance at intervals of 3-6 months, depending on the patient’s risk profile. Maintenance visits include professional cleaning, monitoring of periodontal pockets, and reinforcement of oral hygiene instructions. High-risk patients (e.g., smokers, diabetics) should have tailored maintenance programs based on their individual risk factors. Meta-analyses show that regular PMT significantly reduces the likelihood of disease recurrence compared to less frequent visits (Reference available in book). Patient behavior is a critical factor in the success of periodontal therapy. Evidence shows that patients who adhere to oral hygiene practices and regular follow-up visits have better long-term outcomes. Effective plaque control is essential for the success of periodontal therapy. Studies indicate that providing patients with detailed instructions and tools, such as interproximal brushes and electric toothbrushes, can improve clinical outcomes (Reference available in book). Smoking cessation programs are an evidence-based adjunct to periodontal treatment. Research has shown that quitting smoking improves the response to periodontal therapy and enhances healing (Reference available in book).

Addressing systemic health

Integrating systemic health management into periodontal care is essential. Evidence suggests that controlling systemic conditions such as diabetes and cardiovascular disease can significantly improve periodontal treatment outcomes. Numerous studies show that well-controlled diabetics have similar periodontal outcomes to non-diabetics. In contrast, poorly controlled diabetes is associated with higher treatment failure rates. Periodontal treatment has been shown to reduce systemic inflammation markers, such as C-reactive protein (CRP) and interleukin-6 (IL-6), which are linked to cardiovascular diseases.

Conclusion

Treatment failure in periodontal therapy has profound clinical implications, ranging from continued periodontal destruction and tooth loss to systemic health risks and diminished quality of life. A comprehensive understanding of the factors contributing to failure, combined with meticulous treatment planning, patient education, and long-term maintenance, is crucial for minimizing failure and ensuring successful outcomes. An evidence-based approach to managing periodontal therapy failures involves comprehensive diagnosis, personalized treatment planning, the integration of non-surgical and surgical therapies, and consistent patient management and education. By relying on the latest research and clinical evidence, clinicians can improve treatment outcomes, prevent disease recurrence, and ensure long-term periodontal health.

References

References are available in the hardcopy of the website “Periobasics: A textbook of Periodontics and Implantology”.