[Clinical evaluation for coronectomy of the impacted mandibular third molars in close proximity to inferior alveolar nerve].

PURPOSE: To evaluate the outcome of coronectomy for management of impacted mandibular third molars in close proximity to inferior alveolar nerve (IAN). METHODS: Ten patients with impacted mandibular third molars which approached or was close to the inferior alveolar nerve diagnosed on panoramic film and cone-beam CT (CBCT) scan were included in the study. Coronectomy was conducted at the cemento-enamel junction, leaving the roots below the alveolar crest and primary closure was performed. After the root apex was pushed away from the inferior alveolar nerve, the impacted lower third molar was then removed. RESULTS: Ten patients had little post-operative pain and swelling, none of them had IAN injury or infection. Only 1 patient was failed to move the roots away from IAN and the roots were left in the alveolar socket, but without any symptoms and side effects during 1 year of follow-up. CONCLUSIONS: Coronectomy is effective in controlling inferior alveolar nerve injury following third molar surgery in radiographically evaluated high risk cases and it has very low incidence of complications.

Geometric analysis of root canals prepared by single twisted file in three different operation modes.

OBJECTIVE: The aim of this study was to evaluate and compare the effects of a single twisted file (TF) instrument in three different operation modes on the preparation of curved root canals in human molars and to explore a new possible method in canal shaping in the clinic setting. MATERIALS AND METHODS: A total of 105 selected root canals with an angle of curvature ranging from 20° to 35° were divided into the following three groups with 35 samples each according to the different operation mode in canal preparation: "continuous rotation-500" (CR, 500 rpm), reciprocating movement-300 (RM-300 rpm) and CR-300 rpm. Root canals were prepared by single file (a size 25/0.06 TF). The pre- and post-instrumented images of the sections were scanned using a cone-beam computed tomography scanner to measure the root transportation and centering ratio. The data were evaluated at 1.5 mm, 3.0 mm and 6.0 mm positions from the apex. The significance level was set at P < 0.05. RESULTS: The results showed a statistically significant difference in root transportation that was only found in cross-sections 3.0 mm from the anatomic apex between group "CR-500" and group "CR-300." In addition, a significant difference in centering ratio was found between group "RM-300" and group "CR-300." There was no significant difference in the two indices among the three groups at cross-sections 1.5 mm and 6 mm from the apex. CONCLUSIONS: Under the three conditions of this study, the continuous rotation mode has better shaping ability in root canal preparation than the RM mode when used with a TF single file (size 25/0.06).

Therapeutic potential of IFN-gamma-modified dendritic cells in acute and chronic experimental allergic encephalomyelitis.

Dendritic cells (DC) are antigen-presenting cells specialized to regulate immune responses. DC not only control immunity, but also maintain tolerance to self-antigens-two complementary functions that would ensure the integrity of the organism in an environment full of pathogens. Here we report that splenic DC that had been exposed in vitro to IFN-gamma (IFN-gamma-DC) exhibit therapeutic potential on acute experimental allergic encephalomyelitis (EAE) in Lewis rats, and on chronic-relapsing EAE in B6 and SJL/J mice. During incipient EAE [day 5 post-immunization (p.i.) in rats, day 7 p.i. in mice], IFN-gamma-DC were injected s.c. Severity of clinical signs of EAE was dramatically inhibited in animals injected with IFN-gamma-DC, showing normal magnetic resonance imaging (MRI) of the spinal cord and brain. In contrast, the EAE rats receiving PBS or naive DC had severe clinical signs with multiple and extensive MRI lesions in the spinal cord and brain. IFN-gamma-DC triggered an antigen-specific IFN-gamma production, and induced apoptosis of CD4(+) T cells possibly through DC expressing indoleamine 2,3-dioxygenase and/or an IFN-gamma-dependent pathway. As a result, infiltration of macrophages and CD4(+) T cells within the spinal cords was dramatically reduced in animals injected with IFN-gamma-DC as compared to animals injected with PBS or naive DC. This approach may represent a novel possibility of individualized immunotherapy using autologous, in vitro modified DC as a complement to conventional therapy in multiple sclerosis and other diseases with an autoimmune background.