Validation and spectrophotometric analysis of crown discoloration induced by root canal sealers.

OBJECTIVES: A major cause of crown discoloration is root canal sealer remnants in the pulp chamber, after root canal obturation. The aim of this study was the evaluation of the chromogenic effect of common and new-generation root canal sealers. The tested null hypothesis was that none of the sealers induced clinically perceptible crown discoloration, ex vivo (H(0): CIE color difference ∆Ε < 3.7). METHODS: The crowns of 80 intact, fully developed third mandibular molars were cross-sectioned 1 mm below the cementoenamel junction and stored in standard conditions (100 % humidity, 37 °C). The pulp chambers were chemomechanically debrided with hand files and sodium hypochlorite (NaOCl) and the specimens were randomly assigned into four experimental (1-4) and one control (5) groups. In the experimental groups, the internal axial walls of the pulp chambers were coated with sealers (Group 1; Roth 811, Group 2; AH26, Group 3; GuttaFlow, Group 4; Epiphany SE). The pulp chambers of the control group (Group 5) remained unfilled. The spectral reflectance lines of the crowns were recorded by a UV-Vis spectrophotometer. CIE total color differences [Formula: see text] were calculated after 1 week, 1 month, 3 months, and 6 months, respectively. A pilot study was also conducted for the validation of the experimental model. Two-way mixed ANOVA models were used for statistical data analysis. RESULTS: The experimental model presented values of ∆Ε < 1 unit and high positive correlation values, after repeated measurements (p < 0.05). Roth 811 sealer (Group 1) induced clinically perceptible crown discoloration (∆Ε > 3.7, p < 0.05) and presented statistically significant differences from Groups 2-5 in all examination intervals (p < 0.05). In Groups 2-5, clinically perceptible crown discoloration was not observed (∆Ε < 3.7, p < 0.05). CONCLUSIONS: Roth 811 sealer exhibited severe discoloration effects. Within the limitations of this study, it can be concluded that any sealer remnants should be removed from the pulp chamber after root canal obturation and before placement of a final restoration. CLINICAL RELEVANCE: The chromogenic potential may play an important role in selecting proper root canal sealers.

Transmigration of impacted canines: prevalence, management and implications on tooth structure and pulp vitality of adjacent teeth.

The aim of this study was to estimate the prevalence of transmigrant canines in a sample of panoramic radiographs of a random Greek population, to classify them and evaluate clinically and radiographically all the implications for adjacent teeth. Panoramic radiographs of 3,586 patients retrieved from eight private practices between 1998 and 2009, were examined. Panoramic radiographs with extracted canines were not included in this study. An impacted canine was considered to be transmigrant when at least part of its length had crossed the midline. Six radiographs exhibited transmigrant canines (0.17% of the total sample of panoramic radiographs), of which four were mandibular and two maxillary. Canine transmigration is a rare phenomenon in Greek population. The impact of transmigrant canines on adjacent teeth varied from inclination, calcific metamorphosis and root resorption to no effect. Orthodontic therapy was the treatment of choice for two of the cases, while in the remaining cases the patients were scheduled for periodic recalls. Clinical and radiographic evaluation and early diagnosis are crucial aids in proper treatment planning.

The effect of needle-insertion depth on the irrigant flow in the root canal: evaluation using an unsteady computational fluid dynamics model.

INTRODUCTION: The aim of this study was to evaluate the effect of needle-insertion depth on the irrigant flow inside a prepared root canal during final irrigation with a syringe and two different needle types using a Computational Fluid Dynamics (CFD) model. METHODS: A validated CFD model was used to simulate irrigant flow from either a side-vented or an open-ended flat 30-G needle positioned inside a prepared root canal (45 .06) at 1, 2, 3, 4, or 5 mm short of the working length (WL). Velocity, pressure, and shear stress in the root canal were evaluated. RESULTS: The flow pattern in the apical part of the root canal was similar among different needle positions. Major differences were observed between the two needle types. The side-vented needle achieved irrigant replacement to the WL only at the 1-mm position, whereas the open-ended flat needle was able to achieve complete replacement even when positioned at 2 mm short of the WL. The maximum shear stress decreased as needles moved away from the WL. The flat needle led to higher mean pressure at the apical foramen. Both needles showed a similar gradual decrease in apical pressure as the distance from the WL increased. CONCLUSIONS: Needle-insertion depth was found to affect the extent of irrigant replacement, the shear stress on the canal wall, and the pressure at the apical foramen for both needle types.

Ex vivo study of the efficiency of two techniques for the removal of mineral trioxide aggregate used as a root canal filling material.

The purpose of this study was to evaluate the removal efficiency of mineral trioxide aggregate (MTA) used as a root filling material. Ninety-three human teeth prepared with a step-back technique were randomly assigned to 2 groups and filled with vertically compacted MTA (group A) or MTA and a gutta-percha cone (group B). Fillings were removed by using ultrasonics and/or rotary nickel-titanium instruments. Roots were split into halves, and a 1 to 4 scoring system was used to assess the amount of residue. Data were analyzed with Kruskal-Wallis and Mann-Whitney tests. Remnants were found in all specimens. Rotary instruments were unable to penetrate canals in group A. The combination of rotary instruments and ultrasonics was superior in group B. Dark discoloration of most MTA fillings was evident. The results suggest that MTA cannot be completely removed from the root canal system by any of the methods examined.

Endodontic treatment in cases of allergic reaction to rubber dam.

The prevalence and severity of latex allergies have rapidly increased recently. This article presents two cases of patients with rubber latex allergy. The patient in case A was unaware of her sensitivity to latex and presented symptoms of contact dermatitis-stomatitis during endodontic treatment. The patient in case B reported latex allergy before the initiation of the treatment and a different approach was followed. Certain aspects of latex allergy related to the endodontic treatment are discussed. Moreover, a protocol is proposed for treatment of patients with latex hypersensitivity with safety.