Effect of ultrasonic and sonic activation of root canal sealers on the push-out bond strength and interfacial adaptation to root canal dentine.

AIM: To evaluate the effect of ultrasonic and sonic activation of two root canal sealers on interfacial adaptation and push-out bond strength (BS) to root canal dentine. METHODOLOGY: The root canals of seventy-eight roots of maxillary canines were prepared with NiTi rotary instruments under irrigation with 2.5% NaOCl and 17% EDTA. Canals were filled by lateral condensation of gutta-percha and AH Plus (n = 39) or MTA Fillapex (n = 39). Three subgroups (n = 13) were formed according to sealer activation: no activation (NA), sonic activation (SA, 20 s) and ultrasonic activation (US, 20 s). In three specimens of each subgroup, 0.1% rhodamine B was added to the sealer. Three 1-mm-thick slices were obtained from each root third. The first and second were used for push-out BS test and the third for a qualitative analysis of interfacial adaptation (gaps) and voids by confocal laser scanning microscopy (CLSM). Intratubular penetration of rhodamine B-labelled sealer was also assessed by CLSM. Data were analysed by two-way anova and Tukey's test (α = 0.05). RESULTS: AH Plus (2.58 ± 1.21) had higher push-out BS than MTA Fillapex (1.45 ± 0.71) (P = 0.000). UA (2.64 ± 1.44) had higher BS (P = 0.000) than NA (1.58 ± 0.73) and SA (1.83 ± 0.85), which did not differ significantly from each other (P = 0.3303). The coronal third had higher BS (2.48 ± 1.49) than the middle (2.08 ± 0.94) (P = 0.0003) and apical (1.48 ± 0.58) (P = 0.00) thirds. For both sealers, UA was associated with a more homogeneous filling material with better interfacial adaptation and greater quantity, density and length of tags in dentinal tubules. When UA was used, the tags had similar quantity, density and length to those formed without activation, but interfacial gaps and voids were observed. CONCLUSION: Ultrasonic activation was associated with higher BS values, deeper intratubular penetration and greater interfacial adaptation to root dentine than sonic activation and no activation techniques, AH Plus had higher BS values than MTA Fillapex irrespective of the type of activation.

Ex vivo evaluation of four final irrigation protocols on the removal of hard-tissue debris from the mesial root canal system of mandibular first molars.

AIM: To evaluate the efficacy of four final irrigation protocols on the reduction of hard-tissue debris accumulated within the mesial root canal system of mandibular first molars using micro-CT analysis. METHODOLOGY: Forty mesial roots of mandibular molars with a single and continuous isthmus connecting the mesiobuccal and mesiolingual canals (Vertucci's Type I configuration) were selected and scanned at a resolution of 8.6 µm. Canals were enlarged sequentially using WaveOne Small and Primary instruments activated in reciprocating motion without intracanal irrigation to allow debris to accumulate within the mesial root canal system. Then, specimens were anatomically matched and distributed into four groups (n = 10), according to the final irrigation protocol: apical positive pressure (APP), passive ultrasonic irrigation (PUI), Self-adjusting File (SAF) and XP-endo Finisher (XPF). The final irrigation procedures were performed over 2 min using a total of 5.5 mL of 2.5% NaOCl per canal. Reconstructed data sets were coregistered, and the mean percentage reduction of accumulated hard-tissue debris after the final irrigation procedures was compared statistically between groups using the anovapost hoc Tukey test with a significance level set at 5%. RESULTS: Reduction of accumulated hard-tissue debris was observed in all groups after the final irrigation protocol. Overall, PUI and XPF groups had higher mean percentage reductions of accumulated hard-tissue debris (94.1% and 89.7%, respectively) than APP and SAF groups (45.7% and 41.3%, respectively) (P < 0.05). No significant differences were found when comparing the results of PUI and XPF groups (P > 0.05) or APP and SAF groups (P > 0.05). CONCLUSIONS: The PUI technique and XP-endo Finisher instrument were associated with significantly lower levels of AHTD compared with conventional irrigation and the modified SAF system protocol in mesial root canals of mandibular molars.

Use of a dissolved oxygen microsensor for assessing the viability and thickness of microbial biofilm on root surfaces.

AIM: To evaluate the use of a dissolved oxygen microsensor (DOMS) for assessing the viability and thickness of microbial biofilms on the apical external surface of contaminated human tooth roots. METHODOLOGY: Apical biofilm formation was evaluated in 15 roots contaminated in vitro with a polymicrobial mixture of Staphylococcus aureus, Enterococcus faecalis, Pseudomonas aeruginosa and Candida albicans for 7, 21 and 60 days and in three freshly extracted roots with associated radiographically visible periapical lesions. In each root, the thickness and viability (measured by the amount of dissolved oxygen) of biofilm formed on the apical 2 mm were examined with the DOMS. Scanning electron microscopy (SEM) was used as an auxiliary analysis to confirm the existence of the biofilms detected by the DOMS. RESULTS: The DOMS detected dissolved oxygen on the biofilms formed on the three residual roots up to thickness of 375 µm, 480 µm and 1650 µm. In the 15 roots contaminated in vitro, the DOMS detected dissolved oxygen in six specimens up to thicknesses from 75 to 250 µm, and the intensity of the metabolic activity (biofilm thickness) was directly proportional to the contamination time. SEM confirmed the presence of biofilm in all roots. CONCLUSION: The dissolved oxygen microsensor allowed the measurement of the amount of dissolved oxygen in the biofilm, which is indicative of the intensity of the microbial metabolic activity (viability), correlating the results with biofilm thickness. The DOMS was effective in freshly extracted roots, but had limitations in roots contaminated in vitro after short periods (7 and 21 days) of contamination.

Impact of remaining zinc oxide-eugenol-based sealer on the bond strength of a resinous sealer to dentine after root canal retreatment.

AIM: To evaluate the bond strength of a resin-based sealer (AH Plus) to root canal dentine after the removal of a zinc oxide-eugenol-based sealer (Endofill), using different retreatment techniques. METHODOLOGY: The root canals of sixty-four maxillary incisors were prepared with ProTaper and filled with Endofill/gutta-percha. After thermocycling, the roots were randomly assigned according to the retreatment technique (n = 16): (A) ProTaper, (B) ProTaper/xylol, (C) ultrasound and (D) ultrasound/xylol and according to whether an operating microscope (OM) was used or not (n = 8): GI- direct vision (DV) and GII- indirect through the OM. Eight additional roots were instrumented and filled with AH Plus/gutta-percha (control). Roots were sectioned to obtain 1-mm-thick slices. Slices were used in the push-out test and in confocal microscopy. Data were submitted to anova and Tukey test (α = 0.05). RESULTS: The specimens filled under the OM (2.50 ± 0.90) had higher bond strength values of sealer to root canal walls (P < 0.05). The control group had superior mean adhesion values (4.75 ± 1.47) that were significantly different from the others (P < 0.05). Ultrasound/xylol (2.53 ± 1.00) was superior to ultrasound (2.23 ± 0.72) (P < 0.05), ProTaper (2.20 ± 0.69), ProTaper/Xylol (2.12 ± 0.65), which were similar (P > 0.05). Bond strength was different in all thirds (P < 0.05) and decreased in the following sequence: cervical (3.19 ± 1.18), middle (2.58 ± 1.21) and apical (1.87 ± 0.68). Confocal analysis revealed residues of Endofill in dentinal tubules when the removal protocol was carried out with ProTaper, but not from ultrasound combined with xylol. CONCLUSIONS: The OM was associated with higher bond strength values for filling material to root canals. The zinc oxide-eugenol-based sealer negatively affected the bond strength of AH Plus to root canal walls, regardless of the retreatment technique.

Confocal microscopy assessment of filling material remaining on root canal walls after retreatment.

AIM: The percentage of Endofill remaining on canal walls after retreatment with different techniques was evaluated using confocal microscopy and qualitative analysis of the interface between the filling material/dentine. METHODOLOGY: Sixty-four root canals of incisors were prepared with ProTaper, filled with gutta-percha and Endofill mixed with 0.1% rhodamine B. The roots were thermocycled and distributed into groups according to the method of evaluation: GI - direct viewing (DV) and GII - operating microscope (OM) and according to the removal technique: A) ProTaper retreatment (PR), B) PR/xylol, C) ultrasound and D) ultrasound/xylol. The root canals were then refilled with gutta-percha and AH Plus with 0.1% fluorescein and sectioned at 2, 4 and 6 mm from the apex. The percentage of remaining Endofill was analysed by confocal microscopy. Additionally, 16 roots were prepared with a ProTaper F5 instrument and were filled with Endofill + 0.1% rhodamine B/gutta-percha (negative control group) (n = 8), and the positive control group (n = 8) were filled with AH Plus with 0.1% fluorescein/gutta-percha. RESULTS: Three-way anova demonstrated differences in the method of evaluation, removal techniques and their interaction (P < 0.05). OM (26.15 ± 12.16%) had a smaller percentage of remaining sealer than DV (32.77 ± 14.47%). The Tukey's test revealed that ultrasound/xylol (15.77 ± 7.15%) led to lower percentages of remaining sealer, significantly different from the PR group (35.25 ± 13.63%), PR/xylol (33.03 ± 11.64%) and ultrasound (33.79 ± 11.71%), which were similar (P > 0.05). Qualitative analysis detected that ultrasound had lower remaining Endofill than PR, particularly when combined with xylol. Operating microscope resulted in lower residual sealer, regardless of the removal technique. CONCLUSIONS: None of the protocols was associated with complete removal of the filling material; however, the use of ultrasound/xylol under an OM provided better results.

Immunophenotypic characterization and distribution of dendritic cells in odontogenic cystic lesions.

OBJECTIVE: To analyze the expression and distribution patterns of mature dendritic cells (mDCs) and immature DCs (imDCs) in radicular cysts (RCs), dentigerous cysts (DtCs), and keratocystic odontogenic tumors (KCOTs). MATERIALS AND METHODS: Forty-nine odontogenic cystic lesions (OCLs) (RCs, n = 20; DtCs, n = 15; KCOTs, n = 14) were assessed using the following markers: S100, CD1a and CD207 for imDCs; and CD83 for mDCs. RESULTS: Almost all cases were S100, CD1a, and CD207 positive, whereas 63% were CD83 positive. RCs presented greater number of immunostained cells, followed by DtCs, and KCOTs. The number of S100+ cells was greater than both CD1a+ and CD207+ cells (P < 0.001), which showed approximately similar amounts, followed by lower number of CD83+ cells (P < 0.001) in each OCL type. Different from S100+ cells, both CD1a+ and CD207+ cells on the epithelium (P < 0.05) and CD83+ cells on the capsule (P < 0.05) were preferentially observed. In RCs, significant correlation was found between the thickness epithelium with S100+ and CD1a+ cells, and between the degree of inflammation with CD83+ cells. CONCLUSIONS: Dendritic cell populations in OCLs can be phenotypically heterogeneous, and it could represent distinct lineages and/or functional stages. It is suggested that besides DC-mediated immune cell interactions, DC-mediated tissue differentiation and maintenance in OCLs should also be considered.

Parathyroid hormone/parathyroid hormone-related peptide receptor 1 expression in odontogenic cystic lesions.

AIM: To evaluate parathyroid hormone/parathyroid hormone-related peptide receptor 1 (PTHR1) expression in odontogenic cystic lesions and to compare immunoexpression between the lesions. METHODOLOGY: Thirty-five radicular cysts, 22 dentigerous cysts and 17 keratocystic odontogenic tumours were evaluated. Immunohistochemical reactions against PHTR1 were carried out in 3-µm histological sections, and the expression and the intensity of PTHR1 expression were evaluated. For statistical analysis, the Fisher exact test was used, with a significance of 5%. RESULTS: The intensity of expression in the epithelial lining was significantly weaker in the radicular cyst (P = 0.007). However, in the fibrous capsule, the radicular cyst presented higher positivity for PTHR1 (P = 0.04). CONCLUSIONS: The probable co-expression of PTHrP and PTHR1 in odontogenic cystic lesions may eventually have an autocrine and/or paracrine stimulus in the epithelial and mesenchymal cells, inducing proliferation and lesion growth.

Effect of intracanal irrigants on the bond strength of epoxy resin-based and methacrylate resin-based sealers to root canal walls.

AIM: To assess the bond strength of Epiphany and AH Plus sealers to root canal walls using a push-out test after use of several endodontic irrigants. METHODOLOGY: Roots of 100 maxillary canines were sectioned horizontally 5 mm below the cemento-enamel junction to provide 4-mm-thick dentine disks that were embedded in acrylic resin and had their root canals prepared with a tapered bur (larger diameter=2.70 mm; smaller diameter=2.30 mm; length = 4 mm). The specimens were randomly assigned to five groups (n=20) according to the dentine surface treatment: I - 1% NaOCl (30 min); II - 1% NaOCl (30 min) + 17% EDTA (5 min); III - 17% EDTA (30 min); IV - 24% EDTA gel (30 min); V - 2% chlorhexidine gluconate (CHX) gel (30 min). In each group, two specimens were prepared for scanning electron microscopy to examine the surface of root canal dentine after use of each irrigant. The other 18 specimens were filled with AH plus (n = 9) or Epiphany (n=9) and subjected to a push-out test in an Instron machine. Data (in MPa) were subjected to statistical analysis by two-way anova and post-hoc Tukey-Kramer test (P < 0.05). RESULTS: AH Plus had a significantly higher bond strength (8.74 ± 2.75) than Epiphany (6.74 ± 3.97) (P < 0.05). One per cent NaOCl/17% EDTA was associated with significantly higher bond strength values (10.88 ± 3.05) than the other irrigants (P < 0.05). Seventeen per cent EDTA (8.75 ± 1.75), 24% EDTA gel (7.48 ± 3.48) and 2% CHX gel (7.89 ± 3.41) had intermediate values that were not significantly different from each other (P > 0.05). One per cent NaOCl was associated with the lowest mean values (3.70 ± 0.86) (P < 0.05). The interaction between surface treatment and sealer revealed significantly higher bond strength for 24% EDTA gel with AH Plus, 2% CHX gel with AH Plus and 1%NaOCl/17%EDTA with Epiphany (P < 0.05). CONCLUSION: Except for 1% NaOCl, the removal of smear layer with the other irrigants increased the bond strength of AH Plus to intracanal dentine. The use of 1% NaOCl for 30 min with 17% EDTA as final irrigant for 5 min increased the bond strength of Epiphany.

Push-out strength of root fillings with or without thermomechanical compaction.

AIM: To evaluate the influence of thermomechanical compaction (Tagger's hybrid technique - THT) on the push-out strength of several root filling materials to root dentine. METHODOLOGY: Root canals of eighty roots in human canines were prepared with the ProTaper system and filled with one of the following materials, using either lateral compaction (LC) (n = 40) or THT (n = 40): AH Plus/gutta-percha (GP) (n = 10), Sealer 26/GP (n = 10), Epiphany SE/Resilon (n = 10) and Epiphany SE/GP (n = 10). Three 2-mm-thick dentine slices were obtained from each third of each root. The root filling in the first slice was subjected to a push-out test to evaluate the bond strength of the materials to intraradicular dentine. Data (in MPa) were analysed using anova and post hoc Tukey's test (P < 0.05). Failure mode was determined at × 25 magnification. The other two slices were prepared for scanning electron microscopy (SEM) to examine the surface of the filling materials. RESULTS: Lateral compaction (1.34 ± 1.14 MPa) was associated with a significantly higher bond strength (P < 0.05) than the THT (0.97 ± 0.88 MPa). AH Plus/GP (2.23 ± 0.83 MPa) and Sealer 26/GP (1.86 ± 0.50 MPa) had significantly higher bond strengths than the other materials and differed significantly from each other (P < 0.05). There was a significant difference (P < 0.05) between the coronal (1.36 ± 1.15 MPa), middle (1.14 ± 1.05 MPa) and apical thirds (0.95 ± 0.83 MPa). Considering the technique and root filling material interaction, AH Plus/GP-LC was associated with the highest mean values (2.65 ± 0.66 MPa) (P < 0.05). Sealer 26/GP-LC (2.10 ± 0.46 MPa), AH Plus/GP-THT (1.81 ± 0.78 MPa) and Sealer 26/GP-TH (1.63 ± 0.44 MPa) had intermediate values that were not significantly different from each other (P > 0.05). Epiphany SE was associated with the lowest mean values (3.70 ± 0.86 MPa) (P < 0.05), regardless of the root filling technique and type of solid material (cone). Adhesive failures predominated in the specimens filled with Epiphany SE, whilst mixed and cohesive failures were more frequent in those filled with AH Plus and Sealer 26, regardless of the root filling technique. SEM analysis revealed that LC produced a dense and well-compacted filling whilst the use of a hybrid thermomechanical technique resulted in the solid material (GP or Resilon) intermingled within sealer to form a nonhomogenous mass. CONCLUSION: Lateral compaction was associated with higher bond strengths of the materials to intraradicular dentine than a hybrid technique using thermomechanical compaction. The greatest push-out strengths were obtained when the canals were filled with LC of AH Plus and GP cones.

Quantitative 3D profilometry and SEM analysis of the adaptation of root-end filling materials placed under an optical microscope.

AIM: To evaluate by 3D profilometry and scanning electron microscopy (SEM), the marginal adaptation of mineral trioxide aggregate (MTA) and Sealer 26 placed in root-end cavities with direct vision or under an optical microscope. METHODOLOGY: The root ends of 52 root filled canine teeth were filled with MTA or Sealer 26 under direct vision or optical microscope (n=13). In each group, eight specimens were analysed by profilometry for measurement of the area and depth of gaps. In the other five specimens, gap area was measured using SEM to verify marginal adaptation and surface characteristic. Data were analysed by parametric (anova and Tukey) and non-parametric (Kruskal-Wallis and Dunn) tests. RESULTS: The assessment of the adaptation of both materials to dentine was not influenced by the mode of visualization, which was confirmed by both profilometry and SEM observations. The voids measured with profilometry for Sealer 26 under direct vision were significantly wider and deeper than those for MTA under direct vision (P<0.05). In SEM, significantly larger gap areas were observed with Sealer 26 (P<0.05). CONCLUSION: Root-end cavities filled with MTA had smaller gaps and better marginal adaptation than Sealer 26.

Histological evaluation of the effectiveness of increased apical enlargement for cleaning the apical third of curved canals.

OBJECTIVE: To evaluate the influence of apical size on cleaning of the apical third of curved canals prepared with rotary instruments. METHODOLOGY: Forty-four mesiobuccal canals of maxillary molars teeth were instrumented to different apical sizes (30, 0.02; 35, 0.02; 40, 0.02; 45, 0.02) using a crown-down technique. After canal preparation, the apical thirds of the roots were submitted to histological processing and examination. The specimens were analysed at 40× magnification and the images were submitted to morphometric analysis with an integration grid to evaluate the percentage of debris and uninstrumented root canal walls. The action of the instruments on the root canal walls was assessed based on the surface regularity, abrupt change on the continuity of root canal walls, and partial or total pre-dentine removal. The results were statistically compared using one-way anova with post hoc Tukey test. Pearson's correlation was performed to identify potential correlations between values. RESULTS: The percentage of uninstrumented root canal dentine was higher when apical enlargement was performed with instruments 30, 0.02 taper (55.64 ± 4.62%) and 35, 0.02 taper (49.03 ± 5.70%) than with instruments 40, 0.02 taper (38.08 ± 10.44%) and 45, 0.02 taper (32.65 ± 8.51%) (P < 0.05). More debris were observed when apical enlargement was performed with instruments 30, 0.02 taper (34.62 ± 9.49%) and 35, 0.02 taper (25.33 ± 7.37%) (P < 0.05). There was a significant correlation between the amount of remaining debris and the perimeter of uninstrumented root canal dentine (r = 0.9130, P < 0.001). CONCLUSION: No apical enlargement size allowed the root canal walls to be prepared completely. Apical third cleanliness could be predicted by instrument diameter.

Push-out strength of methacrylate resin-based sealers to root canal walls.

AIM: To assess the push-out strength of Epiphany SE, Epiphany and Hybrid Root SEAL to the dentine walls of root canals. METHODOLOGY: Sixty roots of canines were prepared and distributed to six groups (n = 10) according to the filling material: GI - Epiphany SE, GII - Epiphany primer and sealer, GIII - Epiphany primer, sealer and resinous solvent, GIV - Clearfil DC Bond and Epiphany sealer, GV - Clearfil, Epiphany sealer and solvent and GVI - Hybrid Root SEAL. Resilon cones were used in all groups. Roots were sectioned transversally to obtain three slices from each third. One slice was subjected to the push-out test (MPa), and results were analysed by anova and Tukey's test (P < 0.05). The other two slices were prepared for scanning electron microscopy (SEM). Failure mode was also analysed. RESULTS: A statistically significant difference (P <0.05) occurred between Hybrid Root SEAL (5.27 +/- 2.07) and the other materials, GI (0.40 +/- 0.23), GII (0.78 +/- 0.45), GIII (0.57 +/- 0.28), GIV (0.40 +/- 0.24) and GV (0.50 +/- 0.41), which did not differ significantly from each other (P > 0.05). Adhesive failures predominated in groups I, II, IV and V, whilst mixed and cohesive failures were the most frequent in groups III and VI, respectively. There were gaps in the adhesive interface of GI and GII, continuity areas of the filling material with dentine in GIV and GV and good adaptation of the interface of GVI. CONCLUSION: Hybrid Root SEAL had greater push-out strength to root canal dentine than Epiphany SE and Epiphany. The use of primer, solvent and adhesive system did not influence the adhesion of Epiphany.

Diagnosis and treatment of odontogenic cutaneous sinus tracts of endodontic origin: three case studies.

AIM: To describe three cases of extraoral sinus tracts, related to infected teeth, which were initially misdiagnosed as skin lesions and inappropriately treated. SUMMARY: The extraoral sinus tracts were initially misdiagnosed as skin lesions. Dermatological surgery was performed and antibiotics prescribed but the lesions did not resolve. Then, a dental cause was sought, and identified. Endodontic intervention resulted in resolution of the problem, confirming the initial misdiagnosis. KEY LEARNING POINTS: Dermatologists and other medical practitioners should be aware that dental extraoral sinus tracts can be confused with skin lesions. A dental aetiology, as part of a differential diagnosis, should be kept in mind with oro-facial skin lesions. If an extraoral sinus tract is of endodontic origin, then elimination of infection through effective endodontic treatment will lead to resolution of the sinus tract. Early correct diagnosis can prevent unnecessary and ineffective antibiotic therapy and/or surgical intervention.

Evaluation of several protocols for the application of ultrasound during the removal of cast intraradicular posts cemented with zinc phosphate cement.

AIM: To evaluate several protocols for the application of ultrasound during removal of cast posts with varying core configurations cemented with zinc phosphate. METHODOLOGY: Sixty maxillary canines were distributed into three groups (n = 20): group 1 - core with 5 mm diameter/height and post diameter of 1.3 mm; groups 2 and 3 - core with the same diameter as the post (1.3 mm) and heights of 5 mm and 3 mm, respectively. Posts/cores were cemented using a standard technique with zinc phosphate cement. Each group was divided into two subgroups according to the ultrasonic vibration mode: point vibration - ultrasonic vibration applied to the core surface for 5 s, on each face totalling 25 s; alternate vibration - intermittent application of ultrasonic vibration for 10 s to the labial and lingual surfaces, 10 s to the mesial and distal surfaces and 5 s to the incisal surface, totalling 25 s. The specimens were submitted to the tensile test using an Instron machine (1 mm min(-1)) and results were analysed by anova and t-test. The failure type was also analysed. RESULTS: Statistical analysis showed significant differences between groups relating to the core preparations (P < 0.05). The lowest mean values of traction force were obtained for group 3 (46.1 +/- 7.7 N), followed by group 2 (89.0 +/- 2.7 N) and group 1 (160.4 +/- 7.5 N). Regarding ultrasonic vibration, the lowest mean was observed with alternate vibration (81.1 +/- 10.1 N), which was significantly lower than the point vibration (115.9 +/- 9.5 N) (P < 0.05). Cohesive failure occurred in all cases. CONCLUSION: A reduction in core diameter/height and intermittent ultrasonic application improved the removal of cast posts cemented with zinc phosphate.

A comparative study of physicochemical properties of AH Plus, Epiphany, and Epiphany SE root canal sealers.

AIM: To assess the physicochemical properties and the surface morphology of AH Plus, Epiphany, and Epiphany SE root canal sealers. METHODOLOGY: Five samples of each material were employed for each test according to ANSI/ADA specification 57. The samples were assigned to four groups: (i) AH Plus; (ii) Epiphany; (iii) Epiphany + Thinning Resin; (iv) Epiphany SE. The distilled water used during the solubility test was submitted to spectrometry to verify the release of calcium ions. The morphologies of the external surface and the cross-section of the samples were analysed by means of a scanning electron microscope (SEM). Statistical analysis was performed by using One-Way ANOVA and post hoc Tukey-Kramer tests with the null hypothesis set as 5%. RESULTS: Setting time, flow and radiopacity results were in accordance with ANSI/ADA requirements whereas the dimensional change of all sealers and solubility of Epiphany did not fulfil ANSI/ADA protocols. AH Plus and Epiphany SE were similar in terms of flow, radiopacity, solubility and dimensional change. The spectrometry test revealed significant calcium ion release from Epiphany with and without the thinning resin. SEM analysis revealed essentially a homogeneous surface with compact layer and some rough areas. CONCLUSIONS: Setting time, flow, and radiopacity tests conformed to ANSI/ADA standardization. The dimensional change in all groups and the solubility of Epiphany were greater than values considered acceptable, with higher amounts of calcium ion release. Epiphany SE revealed more organized, compacted, and homogeneous polymers in a reduced resin matrix when compared with the other groups.

Temperature variation at the external root surface during 980-nm diode laser irradiation in the root canal.

OBJECTIVE: To assess the temperature variation in the cervical, middle and apical thirds of root external wall, caused by 980-nm diode laser irradiation with different parameters. METHODS: The roots of 90 canines, had their canals instrumented and were randomly distributed into 3 groups (n=30) according to the laser potency (1.5 W, 3.0 W and 5.0 W). Each group was subdivided into 3 (n=10) according to the frequency (CM, 100 Hz and 1000 Hz), and each subgroup divided into 2 (n=5): dried canal or filled with distilled water. The maximum temperature values were collected by 3 thermocouples located at each third of the root external wall and recorded by digital thermometers. RESULTS: The groups irradiated in the continuous mode (CM) presented the highest values (11.82+/-5.78), regardless of the canals were dry or not, which were statistically different (p<0.01) from those obtained with 100 Hz (6.22+/-3.64) and 1000 Hz (6.00+/-3.36), which presented no statistical difference between them (p>0.01). The groups irradiated with 5.0 W presented the greatest temperature variation (12.15+/-5.14), followed by 3.0 W (7.88+/-3.92) and 1.5 W (4.02+/-2.16), differing between them (p<0.01). The cervical third of the root presented the highest temperature rises (9.68+/-5.80), followed by the middle (7.66+/-4.87) and apical (6.70+/-4.23), with statistical difference among them (p<0.01). After 30s from the end of irradiation, all the specimens presented temperature variation lower than 10 degrees C. CONCLUSIONS: Application of 980-nm diode laser in the root, at 1.5 W in all operating modes, and 3.0 W, in the pulsed mode, for 20s, can safely be used in endodontic treatment, irrespective of the presence of humidity.

Bond strength of AH Plus and Epiphany sealers on root dentine irradiated with 980 nm diode laser.

AIM: To evaluate the bond strength of AH Plus and Epiphany sealers to human root canal dentine irradiated with a 980 nm diode laser at different power and frequency parameters, using the push-out test. METHODOLOGY: Sixty canine roots were sectioned below the cementoenamel junction to provide 4-mm-thick dentine discs that had their root canals prepared with a tapered bur and irrigated with sodium hypochlorite, ethylenediaminetetraacetic acid and distilled water. The specimens were assigned to five groups (n = 12): one control (no laser) and four experimental groups that were submitted to 980 nm diode laser irradiation at different power (1.5 and 3.0 W) and frequency (continuous wave and 100 Hz) parameters. Half of specimens in each group had their canals filled with AH Plus sealer and half with Epiphany. The push-out test was performed and data (MPa) were analysed statistically by anova and Tukey's test (P < 0.05). The specimens were split longitudinally and examined under SEM to assess the failure modes after sealer displacement. RESULTS: The specimens irradiated with the diode laser and filled with AH Plus had significantly higher bond strength values (8.69 +/- 2.44) than those irradiated and filled with Epiphany (3.28 +/- 1.58) and the nonirradiated controls (3.86 +/- 0.60). The specimens filled with Epiphany did not differ significantly to each other or to the control (1.75 +/- 0.69). There was a predominance of adhesive failures at Epiphany-dentine interface (77%) and mixed failures at AH Plus-dentine interface (67%). CONCLUSIONS: The 980 nm diode laser irradiation of root canal dentine increased the bond strength of AH Plus sealer, but did not affect the adhesion of Epiphany sealer.

Clinical and histological evaluation of granuloma gravidarum: case report.

Granuloma gravidarum is a benign lesion of the oral mucosa which occurs during pregnancy. This case report presents the clinical and histological evaluation and treatment of a granuloma gravidarum in a patient in the 9th month of pregnancy.

Primary xanthoma of the mandible.

Bone xanthomas are rare and are usually are associated with endocrine or metabolic diseases, mainly lipid disorders. In the absence of systemic diseases, the lesion is called a primary xanthoma. Primary mandibular xanthomas are extremely rare. The aim of this report is to describe the clinical and radiographic findings of a primary mandibular xanthoma, discussing the epidemiological features, pathogenesis and differential diagnosis. A 25-year-old man was referred for evaluation of a left mandibular lesion detected in a routine radiographic exam. Radiographically, there was a diffuse, unilocular and radiolucent lesion, with irregular margins located adjacent to the surface from the distal root of the left mandibular third molar. The lesion was excised under local anaesthesia. Microscopically, there were several cells with a foamy and granular cytoplasm and central small, round nuclei, similar to xanthomatous macrophages. No lipid disorders were diagnosed. According to these features, the diagnosis of primary mandibular xanthoma was established. In conclusion, xanthomas of the jaws are rare and all seem to be primary and occur exclusively in the mandible.