The Dynamics of Periapical Lesions in Endodontically Treated Teeth: Rationale for a Clinical Intervention

 

 

 

 

 

By Drs. Tomer Goldberger, Eyal Rosen and Igor Tsesis

Introduction

In various cross-sectional studies a high prevalence of apical periodontitis (AP) in endodontically treated teeth has been reported ranging from 40%–61% (1–3). Bacteria persisting in the root canal system is generally the main reason for the persistence of AP following endodontic treatment (4–9).

Management of the teeth with persistent AP may include nonsurgical endodontic retreatment, surgical endodontic treatment, or tooth extraction (10-11). However, in certain cases it may be considered leaving the tooth without intervention and adopt a long-term follow-up protocol (12). In medicine this approach is defined as a “watchful waiting”, that means closely watching a patient’s condition but not giving treatment unless symptoms appear or change (13). In case of AP, this approach may be considered due to the slowly progress of the diseases and in cases when the risks of treatment are greater than the possible benefits. What may be the consequences of treating or not treating an existing apical pathology is a crucial question, which constitutes the core of the clinical decision-making process endodontics (14).

The long-term dynamics of periapical lesions in endodontically treated teeth and possible influencing factors are not fully elucidated, thus presenting a real clinical dilemma regarding the need for an intervention.

Quality of Coronal Restoration

It is commonly believed that the outcome of root canal treatment is mostly associated with the technical quality of the root filling. Extra attention has been paid to coronal leakage as a potential cause of endodontic failure (15-16). In a study of 1010 endodontically treated teeth, Ray and Trope (17) found that the quality of the coronal restoration had a greater impact on the periradicular status than the quality of the endodontic treatment. Although some studies showed that well-prepared and filled root canals can resist bacterial penetration even without intact coronal restoration (18), other studies stressed the importance of adequate coronal restoration for periapical healing (17, 19).

Quality of Root Canal Filling

The quality of root canal filling is associated with the adequate treatment of roots. It is usually evaluated radiographically and defined as adequate in case all canals were obturated, no voids were present, and the root canal filling ended between 0 and 2 mm short of the radiographic apex. (20) The mail goal of the root canal filling is to establish a bacteria tight seal of the root canal so that oral bacteria cannot reach the periapical tissues and cause disease. Tronstad el al (17) found that if the root canal was not properly obturated, the quality of the coronal restoration had no bearing on the outcome of the endodontic treatment.

Over the years, numerous cross-sectional studies were followed in many other countries which evaluated the influence of the quality of root canal fillings and coronal restorations on the periradicular status of root canal–treated teeth. Those studies had various results; most of them concluded that the periradicular status depended equally on the quality of the root canal filling and the coronal restoration. (21-23)

The Dynamics of Periapical Lesions in Endodontically Treated Teeth That Are Left without Intervention

In a retrospective cohort study (24) consisted of 74 patients with a total of 200 endodontically treated coronally restored teeth having periapical lesions. The dynamics of the included periapical lesions was evaluated based on the periapical index (PAI) score changes between 2 consecutive periapical surveys of at least a 4-year interval. The influence of various factors on lesion dynamics was statistically evaluated. Fifty-seven (28.5%) lesions remained unchanged, 103 (51.5%) lesions worsened (PAI score increased), and 40 (20%) lesions improved (PAI score decreased). Poor root canal filling and poor restoration were the only factors found to adversely affect the long-term dynamics of the periapical lesions (P < .05).

Figure 1. Periapical Index (PAI) Change Between the Two Consecutive Status Surveys

Figure 2: PAI Change in Relation to Root Canal Filling Quality and to Coronal Restoration Quality

Take-Home Message

Poor root canal filling and poor restoration may adversely affect the long-term dynamics of periapical lesions that are left without intervention in endodontically treated teeth. Therefore, in cases of poor root canal filling or poor restoration, further intervention may be indicated. However, in cases when the root canal treatment and the coronal restoration are considered adequate, the teeth with suspected AP may be left without intervention and the “watchful waiting” approach may be adopted.

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Drs. Goldberger, Rosen and Tsesis are from the Department of Endodontics, Maurice and Gabriela Goldschleger School of Dental Medicine, Sackler Faculty of Medicine, Tel Aviv University, Israel. Dr. Rosen is also of the Center for Nanoscience and Nanotechnology, Tel Aviv University, Israel.