Sealer area associated with cold lateral condensation of gutta-percha and warm coated carrier filling systems in canals prepared with various rotary NiTi systems.

AIM: To compare the area of sealer surrounding root fillings completed by two coated carrier systems (Thermafil Obturator and System GT Obturator) and the cold lateral compaction technique, following root canal preparation with two different NiTi rotary systems (Profile ISO and System GT). METHODOLOGY: Sixty extracted human mandibular premolars were instrumented with ProFile ISO 0.06 taper and System GT instruments (n = 30 each). The teeth were divided into four subgroups (n = 15) for filling as following: group 1: ProFile + Thermafil Obturator, group 2: ProFile + Cold Lateral Compaction, group 3: System GT + GT Obturator, and group 4: System GT + Cold Lateral Compaction. In all groups the canals were prepared to a final size of 40, 0.06 taper in accordance with the manufacturer's instructions and Topseal was used as a sealer. Horizontal sections were obtained every 1 mm up to 12 mm from the apical foramen. Sections were digitally photographed under a stereomicroscope and the images were transferred to an IBM-compatible PC for image analysis. The cross-sectional area of the root canal and the area filled by sealer were calculated for each section and compared statistically both at all levels and by grouping the data as apical, middle and coronal segments; using the Kruskal-Wallis test with Bonferroni correction and chi-square tests (P = 0.05). RESULTS: In the apical third (1-4 mm), the GT Obturator (group 3) had significantly less area of sealer (P < 0.05), while the difference between groups 1 and 2 was not significant (P > 0.05). For the middle and coronal thirds, both coated-carrier systems had significantly less area of sealer compared with their laterally compacted counterparts (P < 0.05). CONCLUSIONS: With the combined use of ProFile + Thermafil Obturator and System GT + GT Obturator, significantly less area of sealer occurred than that achieved with both NiTi preparation systems followed by cold lateral compaction.

Comparison of the cytotoxic effects and smear layer removing capacity of oxidative potential water, NaOCl and EDTA.

UNLABELLED: This study compared the smear layer removing capability and cytotoxicity of NaOCl, EDTA and Oxidative Potential Water (OPW). Fifteen extracted single-rooted human upper incisors were examined in three groups. The root canals were enlarged to the apical foramen with K files to size #60 and irrigated with: (a) NaOCl followed by OPW, (b) OPW during and after instrumentation and (c) NaOCl followed by EDTA and NaOCl. The effect of these irrigants on the smear layer was evaluated using a scanning electron microscope. In vitro cytotoxicity of these irrigants was examined by MTT colorimetric assay. We found that the combination of NaOCl and OPW as well as the application of OPW alone, failed to remove the smear layer from the apical third, whereas the EDTA and NaOCl combination achieved complete removal. OPW, when used during and after instrumentation, removed the smear layer in the middle third more effectively than NaOCl followed by OPW. EDTA exerted more cytotoxic effects at all concentrations tested when compared with OPW and NaOCl. IN CONCLUSION: (a) OPW was less cytotoxic than other irrigants but did not effectively remove the smear layer, (b) treatment with EDTA followed by NaOCl efficiently removed of the smear layer, but their cytotoxicity should be considered during endodontic therapy.

Histopathological evaluation of the dental pulps in crown-fractured teeth.

Trauma is a common cause of pulpal damage. In traumatic injuries, the first priority is to protect the vitality of pulps. But the time between the trauma and treatment must be short to preserve vital, noninflamed pulps. The aim of this study was to investigate the histopathological changes in pulpal tissues at different time periods after crown fractures. Twenty-three teeth with enamel and dentin fractures, with and without pulp exposure were evaluated. The reasons for seeking dental treatment were aesthetic consideration, pain, or discomfort. The extirpated pulps were histologically prepared for microscopical evaluation. There was myelin degeneration surrounding the axons and edema in the early posttraumatic stages (17 h). In the later stages (4 to 20 days), the tissues showed varying degrees of inflammation, and neuronal degeneration such as intramyelin edema, aberrant myelin synthesis, and axonal swelling.

Histological and densitometric analysis of the effects of exogeneous heparin on rat pulp tissues.

In this study, the effects of heparin on dentinal resorption was investigated in rats. Animals were injected with 2 x 2 IU/g Na-Heparin subcutaneously for 33 days. Histopathological examination of the anterior teeth revealed capillary proliferation, congestion, and fibrosis in the pulp in addition to resorptive lacunae and degenerative bone spiculae in the peripheral bone tissue. Development of fibrosis in the pulp tissue was verified by densitometric analysis, which revealed a 30% increases in mean density after heparin administration. No resorption at all, however, was seen in dentin.

Serum and parotid saliva testosterone, calcium, magnesium, and zinc levels in males, with and without periodontitis.

Fourteen male patients with periodontitis and 10 patients free of periodontitis were included in the study. The concentrations of testosterone (T), calcium (Ca), magnesium (Mg), and zinc (Zn) were measured in serum and parotid saliva. Patients with periodontitis had increased Ca and decreased Zn serum levels, and they had decreased Ca and increased T levels in parotid saliva. Furthermore, there was a low correlation between parotid saliva T and Mg levels in the patients with periodontitis (r = 0.61, n = 14, t = 2.663, p less than 0.005), and there is an inverse relationship between serum and parotid saliva Mg levels (r = - 0.58, n = 14, t = 2.468, p less than 0.05).

A scanning electron microscope (SEM) study of the smear layer in root canals.

A Scanning Electron Microscope was used to study the so-called "smear layer" produced in biomechanically prepared root canals. Fine, freshly-extracted incisors were used and the canals instrumented with K-type files and irrigated with 5% NaOCI and 3% H2O2. The structure of the "smear layer" produced was investigated.