Cleaning Ability of Irrigants and Orange Oil Solvent Combination in the Removal of Root Canal Filling Materials.

OBJECTIVE: This study investigated the influence of different irrigants and the use of orange oil solvent in the removal of filling materials during root canal retreatment. METHODS: Forty maxillary premolars were shaped using the ProTaper System up to file F3 (size 30, 0.09 taper) and filled by Tagger's hybrid technique using the AH Plus. Samples were randomly assigned to four groups (n=10) according to the irrigating protocol during endodontic retreatment with the ProTaper Universal Re-treatment System: G1, 2% chlorhexidine (CHX) gel; G2, 2% CHX gel with an orange oil solvent; G3, 5% sodium hypochlorite (NaOCl); and G4, 5% NaOCl with an orange oil solvent. Afterwards, the samples were longitu-dinally split into two halves, and the root wall images were prepared by scanning electron microscopy. Two pre-calibrated evaluators analyzed the images using a filling materials remnants score system. Data were statistically analyzed using the Kruskal-Wallis and Dunn's tests (p<0.05). RESULTS: All samples had residual filling materials in the root canal walls after instrumentation. According to the presence of the filling material remnants in the total area of samples, the groups were ranked in the follow-ing order: G2=G4>G1=G3. No statistical differences were found when the CHX and NaOCl were used (p>0.05). Groups in which a solvent was used showed a less effective cleaning ability (p<0.05). The use of NaOCl with solvent presented the highest amounts of filling materials remnants in the critical apical area (p<0.05). CONCLUSION: The use of orange oil with NaOCl or CHX does not improve the removal of residual root canal filling materials.

Evaluation of ionic degradation and slot corrosion of metallic brackets by the action of different dentifrices.

OBJECTIVE: To evaluate the in vitro ionic degradation and slot base corrosion of metallic brackets subjected to brushing with dentifrices, through analysis of chemical composition by Energy Dispersive Spectroscopy (EDS) and qualitative analysis by Scanning Electron Microscopy (SEM). METHODS: Thirty eight brackets were selected and randomly divided into four experimental groups (n = 7). Two groups (n = 5) worked as positive and negative controls. Simulated orthodontic braces were assembled using 0.019 x 0.025-in stainless steel wires and elastomeric rings. The groups were divided according to surface treatment: G1 (Máxima Proteção Anticáries®); G2 (Total 12®); G3 (Sensitive®); G4 (Branqueador®); Positive control (artificial saliva) and Negative control (no treatment). Twenty eight brushing cycles were performed and evaluations were made before (T0) and after (T1) experiment. RESULTS: The Wilcoxon test showed no difference in ionic concentrations of titanium (Ti), chromium (Cr), iron (Fe) and nickel (Ni) between groups. G2 presented significant reduction (p < 0.05) in the concentration of aluminium ion (Al). Groups G3 and G4 presented significant increase (p < 0.05) in the concentration of aluminium ion. The SEM analysis showed increased characteristics indicative of corrosion on groups G2, G3 and G4. CONCLUSION: The EDS analysis revealed that control groups and G1 did not suffer alterations on the chemical composition. G2 presented degradation in the amount of Al ion. G3 and G4 suffered increase in the concentration of Al. The immersion in artificial saliva and the dentifrice Máxima Proteção Anticáries® did not alter the surface polishing. The dentifrices Total 12®, Sensitive® and Branqueador® altered the surface polishing.

Cyclic fatigue resistance of rotary NiTi instruments after simulated clinical use in curved root canals.

The aim of this study was to assess cyclic fatigue resistance in rotary nickel-titanium instruments after simulated clinical use in curved root canals (40-degree, 5-mm radius curve). Thirty-six RaCe rotary NiTi files, size #5, taper 0.04, were divided into 3 groups: Groups A, B and C with one, three and five cycles of use, respectively. Time to failure was recorded with a stopwatch in seconds and subsequently converted to number of cycles to fracture. The data were analyzed statistically by ANOVA and Tukey's test (α=0.05). Five sets of clinically used files (group C) reached significantly lower cycle-numbers before fracture (mean=197.5 cycles) when compared with one set of clinically used files (mean=309.2) and three sets (mean=287.5). Results showed that the number of simulated clinical uses of RaCe instruments for shaping curved canals affects adversely the fatigue resistance of these instruments after five uses.

Lateral radiographic technique: an alternative approach for anterior teeth.

AIM: To describe the lateral radiographic technique, its use and indication. BACKGROUND: The clinician's difficulty in performing the correct diagnosis for some endodontic situations sometimes leads to a compromised treatment of some teeth. Considering this, an alternative radiographic technique for anterior teeth (lateral radiographic technique - LRT) may be used to help endodontic diagnosis. TECHNIQUE: This technique use a periapical radiographic film or sensor that is placed vertically in the anterior portion of maxilla or mandible and with the beam passing perpendicular to the radiographic film its possible to evaluate the possibility of a fenestration on the buccal cortical bone plate; differentiate overextension and overfilling; indentify root fractures; confirm the presence and location of an instrument in the root canal system; and assess the treatment of root perforations. CONCLUSION: LRT is an easy and cheap technique that can be used to help in anterior teeth diagnosis. CLINICAL SIGNIFICANCE: Considering that LRT is easy to perform and available at low cost, it could be utilized more by clinicians in the dental office in order to quickly assist in diagnosis. As a complimentary radiographic examination for anterior teeth, it could become a useful supplement to aid the clinical practice.

Efficacy of sodium hypochlorite, ethylenediaminetetraacetic acid, citric acid and phosphoric acid in calcium hydroxide removal from the root canal: a microscopic cleanliness evaluation.

Rooted molars were subjected to standardized canal instrumentation to a master apical file (MAF). The samples were dressed with Ca(OH)(2), and after 7 days, teeth were reopened and Ca(OH)(2) medication was removed by 1 of 4 different experimental procedures: 2.5% sodium hypochlorite (NaOCl) (n = 10); 17% EDTA-T (n = 10); 10% citric acid (n = 10); or 37% phosphoric acid (n = 10). This was followed by reinstrumentation with MAF plus 15 mL saline solution. The roots were prepared for scanning electron microscopic analysis of the cervical, middle, and apical thirds. Statistical analysis was performed with the Kruskal-Wallis test. EDTA-T and phosphoric acid gave the best results in the apical third, with significant statistical differences compared with other groups. NaOCl gave the worst results. Irrigation with 17% EDTA-T and 37% phosphoric acid is more effective than sodium hypochlorite and citric acid in the removal of calcium hydroxide from the apical third.

Sealing ability promoted by three different endodontic sealers.

INTRODUCTION: The aim of this study was to evaluate the apical and coronal seal of endodontic filling promoted by the combined use of Sealer 26/gutta-percha, Endofill/gutta-percha and Resilon/ Epiphany. MATERIALS AND METHODS: A total of 38 extracted human canine teeth were selected; 10 teeth for each test group and 4 for each control group. After conducting conventional endodontic treatment, the teeth were immersed in saline solution for thirty days, and subsequently sealed and stored in India ink for seven days. They were then cleaned and evaluated for infiltration by stereoscopic microscope. The data were statistically analyzed by ANOVA and Bonferroni tests. RESULTS: The results showed no significant differences between the three groups of filling materials used. CONCLUSION: Within the limitations of this in vitro study, no material showed superiority in their apical and coronal seal.