Roots Of Mandibular First Premolars Research Articles

Cytotoxic, migration, and angiogenic effects of intracanal irrigants on cells involved in revascularization of immature teeth

ObjectiveTo evaluate protocols of root canal irrigation and dentin pretreatment in a cell culture model simulating immature teeth. Cytotoxic, migration, and angiogenic effects of Sodium hypochlorite associated with EDTA (NaOCl/EDTA), NaOCl associated with Smear Clear (NaOCl/SC), and QMix were compared. DesignThree roots of mandibular first premolars had their length and root canal diameter standardized. Root canals were irrigated, and the resulting solutions were diluted in culture medium. Sulforhodamine B (SRB) assay was performed with apical papilla cells and with endothelial cells (HUVECs) to assess cytotoxicity. Polarity index and migration assays of apical papilla cells and sprouting of HUVECs were evaluated. Data were analyzed by ANOVA and Tukey post-hoc tests (p < .05). ResultsIn apical papilla cells, NaOCl/SC and QMix promoted higher cytotoxicity, decreased fraction of elongated cells, and had lower migration speed and shorter migration distance of cells compared to NaOCl/EDTA. Also, HUVECs treated with NaOCl/SC and QMix showed decreased tubule formation in comparison with NaOCl/EDTA. ConclusionsNaOCl/SC and QMix showed unfavorable biological responses of cells involved in revascularization in comparison to NaOCl/EDTA. Further studies with other intracanal irrigants should be performed to improve the balance of root canal disinfection with biological responses.

Prevalence and morphology of multiple roots, root canals and C-shaped canals in mandibular premolars from cone-beam computed tomography images in a Thai population

Background/purposeVariations in root and root canal morphology of mandibular premolars of Thais has not been reported, and understanding these variations enhances endodontic success. The purpose was to investigate prevalence and morphology of multiple roots, root canals and C-shaped canals in mandibular premolars in a Thai population from cone-bean computed tomography (CBCT) images. Materials and methodsA total of 349 first mandibular premolars and 416 second premolars from CBCT images with 0.125-mm voxel size and 60 × 60 mm field of view were evaluated. Number of roots, root canals, and C-shaped canals were recorded and statistically analyzed using chi-square test. Root canal configurations were defined according to the Vertucci's classification. Levels and distances of separated multiple canals were reported. ResultsMultiple roots in mandibular first premolars were found at 5.73% while none of second premolars had. Multiple root canals were found in the first premolars at 19.48% and the second premolars at 3.85%. C-shaped canals (C1/C2) were found in the first premolars at 3.72% and the second premolars at 0.48%. All parameters in the first premolars were significantly higher than in the second premolars (p < 0.01). The majority of multiple root canals were defined as Vertucci's type V (1–2 canals). Multiple root canals were frequently separated at the middle level of roots about 6.5–7.0 mm from the cementoenamel junction. ConclusionPrevalence of multiple roots/root canals and C-shaped canals in mandibular first premolars were significantly higher than in mandibular second premolars. Level of separation in multiple root canals was frequently at the mid-root level.

Root and Canal Morphology of Mandibular Premolar Teeth in a Kuwaiti Subpopulation: A CBCT Clinical Study.

Objective:To study the root and root canal morphology of mandibular premolars in a Kuwaiti subpopulation using cone-beam computed tomography (CBCT).Methods:152 CBCT images were obtained from the radiology department archives of four dental centers in Kuwait. A total of 476 mandibular premolar teeth were analyzed by two observers. The number of roots, root canal configuration types and canal curvature measurements were examined. The relationship between sex, tooth position, and incidence of an additional canal were compared using the chi-square test, and the level of significance was set at 0.05 (P=0.05).Results:The number of roots in mandibular first premolars was one in 73.9%, two in 24.9%, three and four in 1.2%. On the other hand, the number of roots in mandibular second premolars was one in 79.2% and two in 20.8%. Based on Vertucci’s classification system, 18.7% of the teeth were type II followed by type VI (14.3%). The majority of the examined teeth were straight (74.8%) and the incidence of distal root angulation was about 21%. Canal configurations not included in the Vertucci classification were reported in 102 teeth (21.4%). Variability was significantly higher in the second premolars compared to first premolar (P<0.05).Conclusion:The Kuwaiti population has complex root canal morphology in mandibular premolar teeth.

Comparison of Apically Extruded Debris during Retreatment Procedure by Two Types of Endodontic Instruments

Abstract Introduction: During root canal treatment, canal debris is inadvertently extruded through the apex during shaping and cleaning. This happens not only during the routine endodontic cases, but also during the retreatment cases. Objective: This study analyzed in vitro the amount of debris extruded through the foramen using two instrumentation techniques during endodontic retreatment. Materials and methods: Sixty roots of mandibular first premolars were selected, instrumented with anatomical diameter up to size number 40 International Organization for Standardization (ISO) file, and then obturated with gutta-percha and zinc-oxide eugenol sealer by lateral condensation. They were then divided into two groups of 30 each. The first group was instrumented with ISO K-files for gutta-percha removal and the second group was instrumented with Protaper retreatment files and gutta-percha was removed. All teeth were irrigated with distilled water. The debris extruded through the foramen were collected and weighed by an analytical balance. Results: Group II had the lowest average for material extrusion through the foramen followed by group I. When Tukey test for statistical analysis was applied, significant differences among groups were found (p = 0.02). Conclusion: It can be concluded that Protaper retreatment files produce significantly less debris as compared with K-files.