Navigating root canal outcomes From conceptual frameworks to advancing therapies for apical periodontitis

Apical periodontitis (AP) remains a major determinant of endodontic treatment outcome and a potential contributor to systemic inflammation. This thesis investigates how emerging technologies, materials, and minimally invasive concepts influence the management and prognosis of teeth affected by AP.
Chapter 1 presents a narrative review on outcome assessment, emphasizing the lack of standardized definitions and methods across studies. It highlights the need for unified outcome measures, as proposed by the AAE and ESE, to improve the comparability of clinical data. Chapter 2 reports a systematic review assessing the use of CBCT in outcome evaluation. Despite its diagnostic precision, CBCT did not consistently identify reliable prognostic factors or superior success rates compared with periapical radiographs, underscoring the importance of balanced clinical application.
Subsequent chapters examined procedural factors influencing success. Chapters 4–6 explored canal preparation, irrigation, and sealer extrusion. Optimal apical enlargement (ISO ≥30, taper 0.04) was identified for effective disinfection. A first-in-human trial of a novel irrigant (RISA) demonstrated encouraging clinical outcomes (87.5% success). Sealer extrusion did not compromise healing, though outcomes differed between primary (95.8%) and retreatment cases (75%).
Chapters 7–8 investigated minimally invasive and selective retreatment approaches. Selective retreatment achieved comparable healing to full retreatment with greater cost-effectiveness, supporting a patient-centered alternative to conventional retreatment.
Overall, this thesis provides evidence-based insights to optimize clinical decision-making in endodontics, emphasizing biologically driven, conservative, and cost-effective strategies for managing apical periodontitis.