Faculty Bibliography

OBJECTIVE:The present study aimed to assess preoperative levels of patient anxiety and pain before root canal treatment, and to explore variables that may affect these levels. METHODS:Ninety-five patients presenting for an endodontic visit were recruited for the study. A questionnaire was administered. Visual analog scales were used to record levels of pain and anxiety. Data was tabulated, and analysis was performed using the Pearson Chi-Squire test with continuity correction, and the level of significance was set at 0.05 (P=0.05). RESULTS:Anxiety was detected more frequently in females (60%) than in males (33%) (P=0.016). Sixty-two percent of patients who were waiting for a new treatment were anxious, compared to 39% of those who were returning to continue treatment (P=0.049). Sixty-nine percent of patients in pain reported being anxious (P=0.015). Patients aged 18-30 years reported more pain than those older than 30 years (P=0.023). Forty-three percent of new patients reported being in pain, whereas only 20% of patients returning for a treatment reported pain (P=0.027). CONCLUSION/CONCLUSIONS:Anxiety associated with root canal treatment is prevalent, and it was reported primarily by young females who were presenting for a new treatment. Pain and anxiety are highly inter-related, and they are usually reduced after the first endodontic session.

This article demonstrates a methodological approach to diagnosing a periapical radiolucency that could not be diagnosed using only basic clinical and radiographic findings. The patient was a 59-year-old Hispanic female with a small tender mass on the lower gingiva associated with tooth #25. Radiographic appearance demonstrated a well-defined radiolucent lesion at the apices of the mandibular incisors. The patient had no significant medical history. Cone-beam computed tomography (CBCT) showed bony expansion of the buccal plate. Differential diagnosis included non-endodontic unilocular radiolucent lesions in the anterior mandibular region. Biopsy findings were consistent with periapical cemento-osseous dysplasia (PCOD). In conclusion, clinical appearance of PCOD varies from non-expansile and asymptomatic to being expansile and sometimes symptomatic. In the latter cases, it may be necessary to use additional diagnostic tools to confirm the diagnosis.

BACKGROUND AND AIM: Many studies have examined the nature of tissue formed in the canals of immature necrotic teeth, following revascularization in animals and humans. While speculations have been made that regeneration of the pulp tissue might take place in the canal, the tissue has been found to be cementum-like, bone-like, and periodontal ligament-like. The purpose of this study was to histologically examine the tissue in the root canals in immature dog teeth that had been artificially infected and then revascularized. METHODS: Two 4- to 5-month-old mongrel dogs with immature teeth were used in the study. In one dog, four maxillary and four mandibular anterior teeth, and in another dog, four maxillary and five mandibular anterior teeth were used in the experiment. Pulp infection was artificially induced in the immature teeth. Revascularization was performed on all teeth by disinfecting the root canals with sodium hypochlorite irrigation and triple antibiotic intracanal dressing, completed with induction of intracanal bleeding, and sealed with an MTA plug. The access cavity was restored with silver amalgam. The animals were sacrificed 3 months after revascularization procedures. The revascularized teeth and surrounding periodontal tissues were removed and prepared for histological examination. RESULTS: Besides cementum-like, bone-like, and periodontal ligament-like tissues formed in the canals, residual remaining pulp tissue was observed in two revascularized teeth. In four teeth, ingrowth of alveolar bone into the canals was seen; presence of bone in the root canals has the potential for ankylosis. CONCLUSIONS: Within the limitation of this study, it can be concluded that residual pulp tissue can remain in the canals after revascularization procedures of immature teeth with artificially induced pulp infection. This can lead to the misinterpretation that true pulpal regeneration has occurred. Ingrowth of apical bone into the root canals undergoing revascularization can interfere with normal tooth eruption if ankylosis occurs.

INTRODUCTION: Regenerative endodontic therapy is currently used to treat immature permanent teeth with necrotic pulp and/or apical periodontitis. However, mature teeth with necrotic pulp and apical periodontitis have also been treated using regenerative endodontic therapy. The treatment resulted in resolution of apical periodontitis, regression of clinical signs and symptoms but no apparent thickening of the canal walls, and/or continued root development. A recent study in an animal model showed that the tissues formed in the canals of mature teeth with apical periodontitis after regenerative endodontic therapy were cementumlike, bonelike, and periodontal ligament-like tissue with numerous blood vessels. These tissues are similar to the tissues observed in immature permanent teeth with apical periodontitis after regenerative endodontic therapy. METHODS: A 23-year-old woman had a history of traumatic injury to her upper anterior teeth when she was 8 years old. Subsequently, #8 developed pulp necrosis and an acute apical abscess and #7 symptomatic apical periodontitis. The apex of #8 was slightly open, and the apex of #7 was completely formed. Instead of nonsurgical root canal therapy, regenerative endodontic therapy was attempted, including complete chemomechanical debridement on #8 and #7. This was based on the premise that filling of disinfected root canals with the host's biological vital tissue might be better than filling with foreign materials. RESULTS: After regenerative endodontic therapy of #8 and #7, there was radiographic evidence of periapical osseous healing and regression of clinical signs and symptoms. The pulp cavity of #8 decreased in size, and the apex closed. The pulp cavity of #7 appeared to be obliterated by mineralized tissue. These indicated ingrowth of new vital tissue into the chemomechanically debrided canals. CONCLUSIONS: Regenerative endodontic therapy of mature teeth with apical periodontitis and apical abscess can result in the regression of clinical signs and/or symptoms and healing of apical periodontitis but no apparent thickening of the canal walls or continued root development. Filling of the disinfected canals with the host's vital tissue may be better than with foreign materials because vital tissue has innate and adaptive immune defense mechanisms.

INTRODUCTION: Histological studies of immature human permanent necrotic teeth with or without apical periodontitis after revascularization have not been reported. This case report describes the histological findings of tissue formed in the canal space of an immature permanent tooth #9 with irreversible pulpitis without apical periodontitis after revascularization. METHODS: An immature human permanent tooth #9 was fractured 3.5 weeks after revascularization and could not be retained. The tooth was extracted and prepared for routine histological and immunohistochemical evaluation in order to examine the nature of tissue formed in the root canal following the revascularization procedure. RESULTS: At 3.5 weeks after revascularization, more than one half of the canal was filled with loose connective tissue similar to the pulp tissue. A layer of flattened odontoblast-like cells lined along the predentin. Layers of epithelial-like cells, similar to the Hertwig's epithelial root sheath, surrounded the root apex. No hard tissue was formed in the canal. CONCLUSIONS: Based on the histological findings in the present case, regeneration of pulp-like tissue is possible after revascularization. In this case, both the apical papilla and the Hertwig's epithelial root sheath survived in an immature permanent tooth despite irreversible pulpitis but without apical periodontitis.

Chen MY-H, Chen K-L, Chen C-A, Tayebaty F, Rosenberg PA, Lin LM. Responses of immature permanent teeth with infected necrotic pulp tissue and apical periodontitis/abscess to revascularization procedures. International Endodontic Journal ABSTRACT: Aim To report several types of response of immature permanent teeth with infected necrotic pulp tissue and either apical periodontitis or abscess to revascularization procedures. Methodology Twenty immature permanent teeth with infected necrotic pulp tissue and either apical periodontitis or abscesses from 20 patients were included. The teeth were isolated with rubber dam, and pulp chambers was accessed through the crowns. The canals were gently irrigated with 5.25% sodium hypochlorite with minimal mechanical debridement. Calcium hydroxide was used as an inter-appointment intracanal medicament and placed into the coronal half of the canal space. After resolution of clinical signs and symptoms, bleeding was induced into the canal space from the periapical tissues using K-files. The coronal canal space was sealed with a mixture of mineral trioxide aggregate (MTA) and saline solution. The access cavity was filled with composite resin. These immature permanent teeth with infected necrotic pulp tissue and apical periodontitis/abscesses were followed up from 6 to 26 months. Results Five types of responses of these immature permanent teeth with infected necrotic pulp tissue and apical periodontitis/abscess to revascularization procedures were observed: type 1, increased thickening of the canal walls and continued root maturation; type 2, no significant continuation of root development with the root apex becoming blunt and closed; type 3, continued root development with the apical foramen remaining open; type 4, severe calcification (obliteration) of the canal space; type 5, a hard tissue barrier formed in the canal between the coronal MTA plug and the root apex. Conclusions Based on this case series, the outcome of continued root development was not as predictable as increased thickening of the canal walls in human immature permanent teeth with infected necrotic pulp tissue and apical periodontitis/abscess after revascularization procedures. Continued root development of revascularized immature permanent necrotic teeth depends on whether the Hertwig's epithelial root sheath survives in case of apical periodontitis/abscess. Severe pulp canal calcification (obliteration) by hard tissue formation might be a complication of internal replacement resorption or union between the intracanal hard tissue and the apical bone (ankylosis) in revascularized immature permanent necrotic teeth

Lin LM, Rosenberg PA. Repair and regeneration in endodontics. International Endodontic Journal. ABSTRACT: The ideal objective of treatment of established diseases, including irreversible pulpitis and apical periodontitis, is to achieve wound healing. Wound healing can result in repair or regeneration. The ultimate goal of wound healing is to restore the original architecture and biological function of the injured tissue or organ. Although humans are equipped with powerful innate and adaptive immune defence mechanisms, many intrinsic and extrinsic factors can affect wound healing. Complete regeneration following injury in humans can occur only in the pre-natal foetus within 24 weeks of gestation. Post-natal wounds including irreversible pulpitis or apical periodontitis always heal by repair or by a combination of repair and regeneration. Somatic cells, such as fibroblasts, macrophages, cementoblasts and osteoblasts, in the pulp and periapical tissues have limited potential for regeneration following injury and lack of telomerase. Wound healing of irreversible pulpitis and apical periodontitis requires recruitment and differentiation of progenitor/stem cells into tissue-committed somatic cells. Stem cell differentiation is regulated by intrinsic factors and extrinsic micro-environmental cues. Functionality of stem cells appears to show an age-related decline because of the change in intrinsic properties and diminished signals within the extrinsic local and systemic environment that modulate the function of stem cells or their progeny. Infection induces an immuno-inflammatory response and tissue destruction, which hinders the potential of tissue regeneration. Therefore, prevention, early detection and treatment of inflammation/infection of pulpal and periapical disease can enhance regeneration and minimize the repair of pulpal and periapical tissues after endodontic therapy

Tissue regeneration by using membrane barriers and bone grafting materials in periapical surgery is an example of tissue engineering technology. Membrane barriers and/or bone grafts are often used to enhance periapical new bone formation. However, the periapical tissues also consist of the periodontal ligament (PDL) and cementum. For regeneration of the periapical tissues after periapical surgery, one of the important requirements is recruitment and differentiation of progenitor/stem cells into committed pre-osteoblasts, pre-PDL cells, and pre-cementoblasts. Homing of progenitor/stem cells into the wounded periapical tissues is regulated by factors such as stromal cell-derived factor 1, growth factors/cytokines, and by microenvironmental cues such as adhesion molecules and extracellular matrix and associated noncollagenous molecules. Tissue regeneration after injury appears to recapitulate the pathway of normal embryonic tissue development. Multiple tissue regeneration involves a complex interaction between different cells, extracellular matrix, growth/differentiation factors, and microenvironmental cues. Little is known concerning the biologic mechanisms that regulate temporal and spatial relationship between alveolar bone, PDL, and cementum regeneration during periapical wound healing. Simply applying a membrane barrier and/or bone graft during periapical surgery might not result in complete regeneration of the periapical tissues. It has not been clearly demonstrated that these biomaterials are capable of recruiting progenitor/stem cells and inducing these undifferentiated mesenchymal cells to differentiate into PDL cells and cementoblasts after periapical surgery