Overview
Internal resorption is a rare pathological condition characterized by the progressive resorption of tooth dentin from within, often originating from the dental pulp or periodontal ligament. This condition can complicate endodontic treatment and poses a significant threat to tooth retention and overall dental health. It predominantly affects adults but can occur at any age, with females slightly more frequently reported in some studies. Understanding and timely diagnosis of internal resorption are crucial in day-to-day practice to prevent tooth loss and ensure optimal patient outcomes 1.Pathophysiology
Internal resorption typically initiates from the dental pulp or occasionally from the periodontal ligament, driven by an unknown stimulus that triggers odontoclastic activity. The process involves the activation of odontoclasts, which are specialized cells responsible for bone and dentin resorption. These cells migrate from the periodontal ligament or pulp into the dentin, where they secrete enzymes such as tartrate-resistant acid phosphatase (TRAP) and matrix metalloproteinases (MMPs), leading to the degradation of the dentin matrix. The resorption often progresses along the root canal or circumferentially around the root, potentially extending into the periodontal ligament and alveolar bone. The exact triggers for this odontoclastic activation remain unclear but may involve trauma, inflammation, or hormonal influences. Early detection and intervention are critical to halt the resorptive process and preserve the tooth structure 1.Epidemiology
The incidence of internal resorption is relatively low compared to other dental conditions, making precise prevalence figures challenging to establish. Studies suggest it predominantly affects adults, with no significant gender predilection noted in some reports, though slight female predominance has been observed in others. The condition can occur in any tooth but is more frequently reported in anterior teeth, particularly incisors and canines. Geographic and specific risk factors are not well-defined, but certain predisposing factors such as trauma, previous endodontic procedures, and pulpal necrosis have been implicated. Trends over time suggest a stable incidence, though advancements in diagnostic imaging like cone-beam computed tomography (CBCT) have likely improved detection rates 1.Clinical Presentation
Internal resorption often presents insidiously, with patients typically experiencing minimal symptoms in the early stages. Common clinical signs include tooth sensitivity, especially to thermal changes, and occasionally pain or discomfort. Radiographically, the hallmark features are well-defined, often round or oval radiolucencies within the root dentin, which may progressively enlarge and extend towards the root apex or periodontal ligament. Advanced cases may show external root resorption or periapical pathology. Red-flag features include rapid progression of the lesion, significant tooth mobility, and involvement of multiple roots, which necessitate urgent evaluation and intervention 1.Diagnosis
The diagnosis of internal resorption relies on a combination of clinical examination and advanced imaging techniques. Clinicians should initiate the diagnostic process with a thorough history and clinical examination, focusing on symptoms and signs of tooth involvement. Essential diagnostic tools include:Periapical Radiography: Initial screening tool, though limited in detail.
Cone-Beam Computed Tomography (CBCT): Provides detailed three-dimensional imaging crucial for characterizing the extent and nature of the resorption 1.Specific Criteria for Diagnosis:
Radiographic Features: Presence of well-defined, internal radiolucencies within the root dentin.
Lesion Characteristics: Lesions typically originate from the pulp chamber or root canal and extend circumferentially or longitudinally.
CBCT Analysis: Use for precise measurement of lesion dimensions, location, and involvement of root structure.
Differential Diagnosis: Rule out external cervical resorption, cemento-osseous dysplasia, and other internal resorptive conditions through comparative imaging and clinical correlation 12.Differential Diagnosis
External Cervical Resorption: Distinguished by external surface involvement visible on radiographs, unlike the internal nature of internal resorption.
Cemento-Osseous Dysplasia: Typically presents with mixed radiolucent and radiopaque areas, often in specific populations like middle-aged women, and lacks the internal dentin resorption pattern 2.Management
Initial Management
Conservative Approach: For early-stage lesions, non-surgical endodontic treatment aimed at eliminating pulpal infection and inflammation may be attempted.
- Root Canal Therapy: Thorough cleaning and shaping of the root canal system, followed by obturation with gutta-percha and sealer.
- Antibiotics: Consideration for systemic antibiotics if there is evidence of significant periapical infection (e.g., amoxicillin 500 mg TID for 7 days) 1.Advanced Management
Surgical Intervention: Required for extensive lesions that threaten tooth viability.
- Apical Surgery: Root-end resection and retrograde filling if internal resorption extends to the apex.
- Resective Surgery: Removal of resorptive dentin and placement of bone grafts or barrier membranes to promote healing (e.g., guided tissue regeneration techniques).
- Tooth Retention Strategies: Use of internal posts or splinting if tooth retention is deemed necessary 1.Refractory Cases
Referral to Specialist: For cases unresponsive to initial treatments, referral to an endodontist or oral surgeon is advised.
- Advanced Imaging and Planning: Further CBCT scans for detailed planning.
- Multidisciplinary Approach: Collaboration with periodontists or maxillofacial surgeons for complex cases 1.Complications
Tooth Loss: Progression of resorption leading to compromised tooth structure and eventual extraction.
Periapical Pathosis: Development of periapical abscesses or cysts secondary to untreated internal resorption.
Root Fracture: Weakened root structure increasing susceptibility to fractures.
Management Triggers: Prompt referral and intervention are crucial when observing rapid lesion progression, significant mobility, or signs of infection 1.Prognosis & Follow-up
The prognosis of internal resorption varies based on the extent and stage at diagnosis. Early detection and appropriate management generally yield favorable outcomes, with successful preservation of the tooth in many cases. Key prognostic indicators include:
Lesion Size and Extent: Smaller, less extensive lesions have better prognoses.
Treatment Response: Positive response to initial endodontic therapy and surgical interventions.Recommended Follow-up Intervals:
Initial Follow-up: 3-6 months post-treatment to assess healing and lesion stability.
Subsequent Follow-ups: Annually or as clinically indicated, with periodic CBCT scans to monitor lesion progression or recurrence 1.Special Populations
Pediatric Patients: Internal resorption is rare but can occur post-traumatic injuries. Management focuses on conservative approaches initially, with close monitoring due to ongoing tooth development.
Elderly Patients: Increased risk of complications due to compromised healing capacity; multidisciplinary care involving endodontists and periodontists is often necessary.
Specific Comorbidities: Patients with systemic conditions affecting bone metabolism (e.g., osteoporosis) may require tailored treatment plans to enhance bone stability and healing 1.Key Recommendations
Utilize CBCT for Diagnosis: Employ cone-beam computed tomography for detailed assessment of internal resorption to guide treatment planning (Evidence: Strong 1).
Early Intervention is Critical: Initiate treatment promptly upon diagnosis to prevent further resorption and preserve tooth viability (Evidence: Moderate 1).
Surgical Intervention for Advanced Lesions: Consider surgical resective techniques for extensive internal resorption that threatens tooth retention (Evidence: Moderate 1).
Regular Follow-up Monitoring: Schedule periodic radiographic evaluations (e.g., CBCT every 6-12 months) to monitor lesion stability and treatment outcomes (Evidence: Moderate 1).
Refer Complex Cases: Refer patients with refractory or complex internal resorption to specialists for advanced management (Evidence: Expert opinion 1).
Combine Endodontic and Surgical Approaches: Integrate root canal therapy with surgical interventions as needed for comprehensive management (Evidence: Moderate 1).
Consider Antibiotics for Infected Lesions: Use systemic antibiotics in cases with signs of periapical infection to manage associated inflammation (Evidence: Moderate 1).
Evaluate Tooth Retention Strategies: Assess the need for internal posts or splinting in cases where tooth retention is crucial (Evidence: Expert opinion 1).
Monitor for Complications: Regularly screen for potential complications such as tooth loss, periapical disease, and root fractures (Evidence: Moderate 1).
Tailor Management for Special Populations: Adapt treatment plans considering age, comorbidities, and specific patient needs (Evidence: Expert opinion 1).References
1 DeLuca S, Amato R, Finkelman M, Ptak D. Internal Resorption: A Retrospective Cone-Beam Computed Tomography Analysis of 50 Cases With Outcome Assessment. International endodontic journal 2026. link
2 de Sousa SEM, Monteiro LPB, de Castro RF, de Lima Dias Junior LC, de Almeida Rodrigues P, da Silva Brandão JM. Diagnostic Accuracy of Cone-Beam Computed Tomography and Periapical Radiography in Detecting External Cervical Resorption: A Systematic Review and Meta-Analysis. Australian endodontic journal : the journal of the Australian Society of Endodontology Inc 2026. link
3 Reis TMS, Ferrari DR, Junqueira RB, Peyneau PD, Villoria EM, Visconti MA et al.. Features of external root resorption as predictors of disease progression: A CBCT cross-sectional study. Odontology 2026. link
4 Berglundh T, Thilander B, Sagne S. Tissue characteristics of root resorption areas in transplanted maxillary canines. Acta odontologica Scandinavica 1997. link