Factors affecting the periapical healing process of endodontically treated teeth

Abstract

Tissue repair is an essential process that reestablishes tissue integrity and regular function. Nevertheless, different therapeutic factors and clinical conditions may interfere in this process of periapical healing. This review aims to discuss the important therapeutic factors associated with the clinical protocol used during root canal treatment and to highlight the systemic conditions associated with the periapical healing process of endodontically treated teeth. The antibacterial strategies indicated in the conventional treatment of an inflamed and infected pulp and the modulation of the host's immune response may assist in tissue repair, if wound healing has been hindered by infection. Systemic conditions, such as diabetes mellitus and hypertension, can also inhibit wound healing. The success of root canal treatment is affected by the correct choice of clinical protocol. These factors are dependent on the sanitization process (instrumentation, irrigant solution, irrigating strategies, and intracanal dressing), the apical limit of the root canal preparation and obturation, and the quality of the sealer. The challenges affecting the healing process of endodontically treated teeth include control of the inflammation of pulp or infectious processes and simultaneous neutralization of unpredictable provocations to the periapical tissue. Along with these factors, one must understand the local and general clinical conditions (systemic health of the patient) that affect the outcome of root canal treatment prediction.

Figure 1. (A) Presence of dystrophic calcification on the tube opening; (B) Presence of birefringent structures exposed by polarized light; they have been formed by the reaction between the calcium ions derived from the material and the carbonic gas released from the tissues (Sealapex, 30 days, Von Kossa and polarized light; 10×)

Figure 2. Process of obturation from the apical limit; a new cement sealing technique in the apical foramen, in close contact with Sealapex. Observe the normal organization of the periodontal ligament and alveolar bone close to the periapex (HE, 10×)

Figure 3. Obturation over the apical limit showing the absence of new cement sealing the apical foramen in close contact with Sealapex. Observe the partial disorganization of the periodontal ligament with the chronic inflammatory cells surrounding the extruded material and the alveolar bone distant from the periapex (HE, 10×)

Figure 4. Tissue response of the subcutaneous tissue on the 30^th day under normal (A, B, C) and diabetic (D, E, F) conditions. Use of Gray MTA Angelus^® (A) and MTA Fillapex^® (B): in both materials, a mild inflammatory response with the infiltration of macrophages and lymphocytes was evident (hematoxylin-eosin, 10× magnification); Sealapex^® (C): thick, fibrous capsule formation and a moderate inflammatory cell infiltration (hematoxylin-eosin, 10× magnification); Gray MTA Angelus^® (D): presence of a moderate inflammatory infiltration of macrophages and lymphocytes (hematoxylin-eosin, 10× magnification); MTA Fillapex^® (E): presence of a mild inflammatory infiltration of macrophages and lymphocytes after 30 days (hematoxylin-eosin, 10× magnification); Sealapex^® (F): thick, fibrous capsule formation and moderate inflammatory cell infiltration (hematoxylin-eosin, 10× magnification)