Effect of pomegranate solution alone or combined with chlorhexidine against oral multispecies biofilm.

AIM: Natural bioactive products have been tested as alternative antimicrobial agents. This study evaluated the effect of Punica granatum extract (PGE) on oral multispecies biofilms. METHODOLOGY: Lyophilized extracts from pomegranate peel were prepared, and the punicalagin content was assessed by ultra-performance liquid chromatography (UPLC). Oral multispecies biofilms from 2 donors were grown on four collagen-coated hydroxyapatite discs. After incubation for 7 days or 3 weeks, the biofilms were exposed to water (control), 2% CHX, 10% PGE, 20% PGE or 30% PGE for 3 min. The proportions of dead bacteria were assessed by the live/dead staining and confocal microscopy. After the analysis, the best PGE concentration (30%) was combined with CHX. The experimental phases were repeated using water, 2% CHX, 30% PGE and 30% PGE + 2% CHX. Five random areas of the biofilm on each disc were scanned, resulting in 20 scanned areas for each group. RESULTS: Regarding the biofilm volume, no differences were found amongst solutions (p = .111). The PGE solution killed bacteria effectively in 1-week, 2-week and 3-week-old-plaque biofilms, ranging from 37 to 55.3%, depending on the PGE concentration. The 30% PGE (a) (p = .0009) had greater antibiofilm effectiveness than 2% CHX (b), which killed bacteria in the 25.2 to 48.7% range. The 10% and 20% PGE had intermediate values (ab), without significant differences from 30% PGE (p = 1.002). Water (c) had the lowest proportion of dead bacteria (p < .00001) in a range of 5 to 6.7% and lower effectiveness in killing bacteria (p < .05). The PGE alone or mixed with 2% CHX had greater anti-biofilm effectiveness than CHX (p < .05). The old plaque biofilms were more resistant than the 7-day-old plaque (p < .05). CONCLUSIONS: The 30% PGE (alone or combined with CHX) exhibited a greater antibiofilm effect on oral multispecies biofilms grown on hydroxyapatite discs than 2% CHX.

Clinical performance of sealants under different humidity control conditions: a split-mouth 1-year randomized trial.

PURPOSE: Sealants are an effective method of prevention and treatment for early caries lesions. This study analyzed the 1-year clinical performance of resin-based and ionomeric sealants applied to permanent teeth under different humidity conditions. METHODS: The investigation was a triple-blind randomized clinical trial (RCT) with a four arms split-mouth design, divided according to the sealant protocol: (1) Resin-based sealant applied with rubber dam isolation, (2) Resin-based sealant applied with cotton rolls isolation, (3) Ionomeric sealant applied with rubber dam isolation and (4) Ionomeric sealant applied with cotton rolls isolation. Fifty-eight patients started the study (232 teeth), and 47 (188 teeth) remained until the 1-year recall. The modified USPHS criteria were used in the analyzes to investigate surface texture, retention and the presence of secondary caries lesions around the sealants; in the following periods: baseline, after 3, 6, 9, and 12 months by two calibrated examiners. Data were analyzed by the Mann-Whitney and Friedman tests. RESULTS: There was no difference between the types of sealants (p > 0.05). The type of humidity control influenced the superficial texture (p = 0.0012) and the retention of sealants (p = 0.0023). The sealant displacement was greater under cotton rolls isolation. Only one active caries lesion in enamel was found in the 9th month. CONCLUSION: It may be concluded that sealants effectively prevented caries, even when they were partially or totally lost, regardless of the material. The rubber dam isolation with a rubber dam promoted lower surface roughness and improved the retention rates. International Clinical Trials Registry Platform: #1111-1215-2832 (07/26/2018).

Influence of antimicrobial photodynamic therapy with different pre-irradiation times on children's dental biofilm: randomized clinical trial.

PURPOSE: Photodynamic therapy (PDT) is effective in reducing pathogenic microorganisms in the oral cavity and in preventing dental diseases. This study evaluated the pre-irradiation time using PDT (diode laser associated with 0.01% methylene blue) to decrease the number of microorganisms in the visible plaque in permanent teeth. METHODS: This randomized clinical trial included 108 homologous lower permanent first molars (36 and 46) with biofilm from 54 children aged six to 12 years. PDT was performed (0.01% methylene blue photosensitizer/therapeutic laser-InGaAIP), according to the following protocols: Group 1, biofilm collection of the distal area of the lingual surface of 36 µm before PDT; group 2, mesial area of the lingual surface of 36 µm 1 min after PDT; group 3, area of the lingual surface of 46 µm before PDT; and group 4, mesial area of the lingual surface of 46 µm 5 min after PDT. RESULTS: After statistical analysis, significant differences were observed between the groups (p = 0.000). In groups 2 and 4, the number of bacteria tended to decrease, with a more evident bacterial reduction in group 4. CONCLUSIONS: Pre-irradiation reduced the number of colony-forming units of mature bacterial biofilms in vivo. A time of 5 min resulted in a greater reduction in the number of colony-forming units. CLINICAL TRIAL REGISTRATION: ReBEC Identifier: RBR-6bqfp3; Date of Register: March 2nd, 2020. Retrospectively Registered.

Wear profile of canal wall surfaces and bond strength of endodontic sealers after in situ acid challenge.

AIM: To evaluate the wear of root wall surfaces, the bond strength of sealers to dentine and the demineralization around root filling materials after canals were exposed to acid challenge in situ. METHODOLOGY: Eighty-seven roots of mandibular incisors were selected. Thirty-two were used in the laboratory bond strength study (n = 8), and 55 in the in situ study (n = 11). Root canals were prepared biomechanically and then filled with gutta-percha and AH Plus, MTA Fillapex, Sealapex or Endofill. For 14 days, 11 participants used intra-oral devices with five sterilized roots (four experimental and one control - only canal prepared). Drops of sucrose were dripped onto roots allowing the accumulation of biofilm on canal surfaces. Roots were removed, sectioned and analysed for the following: bond strength of filling material using a push-out test and also wear profile and dentine demineralization using confocal microscopy. Bond strength (MPa) was evaluated by two-way anova and Tukey test (α = 0.05), and wear profile was assessed by Kruskal-Wallis and t-tests (α = 0.05). RESULTS: AH Plus had the highest bond strength values. Intermediate results were found in roots with MTA Fillapex and Endofill, whilst Sealapex had inferior results (P < 0.05). No significant differences were found amongst root thirds (P > 0.05). For wear profile, samples were associated with degradation of the filling materials after exposure to the oral environment (P < 0.05). Roots had signs of demineralization around the filling material when Sealapex and Endofill were used. CONCLUSIONS: Sealers were not able to prevent degradation of the adhesive interface and dentine. AH Plus and MTA Fillapex had superior bond strength to dentine and less intense demineralization around the root filling.

Effects of different lasers on organic/inorganic ratio of radicular dentin.

The aim of this study was to evaluate the chemical stability of endodontic-treated root dentin after different laser irradiations through Raman spectroscopy. Fifty maxillary canines were selected and prepared with K3 system. Roots were randomly distributed into five groups (n = 10) according to the surface treatment: GI (water), GII (NaOCl + EDTA), GIII (NaOCl + EDTA + 980 nm Diode laser), GIV (NaOCl + EDTA+ 1064 nm Nd: YAG laser) and GV (NaOCl + EDTA+ 2780 nm Er,Cr: YSGG laser). Lasers were applied for 20 s. Samples were bisected, and the organic and inorganic content of dentin was analyzed by Raman spectroscopy. Data were submitted to ANOVA and Tukey tests (p < 0.05). None of the surface treatments alter the inorganic content (cts) (p = 0.183). Roots irradiated with Er,Cr: YSGG laser had a reduced collagen content (GV-290.7 ± 41.7) compared with the water-treated roots (GI-328.3 ± 63.5) and those treated with NaOCl + EDTA (GII-333.9 ± 55.8). Roots irradiated with Er,Cr: YSGG laser also showed a higher inorganic/organic ratio (GV-9.5 ± 1.1) than roots treated with water (GI-7.7 ± 1.5), NaOCl + EDTA (GII-8.0 ± 1.4) and diode laser (GIII-8.2 ± 1.6). Both organic and inorganic contents increased from cervical to apical thirds in all groups. None of the surface treatments were able to promote changes in the inorganic content of the root dentin; treatment with NaOCl + EDTA combined with Er,Cr: YSGG altered collagen.

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.

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.

Microhardness and SEM after CO(2) laser irradiation or fluoride treatment in human and bovine enamel.

BACKGROUND: It remains uncertain as to whether or not CO(2) laser is able to hinder demineralization of enamel. The possibility to use bovine instead of human teeth on anticariogenic studies with laser has not yet been determined. PURPOSE: To compare the ability of CO(2) laser and fluoride to inhibit caries-like lesions in human enamel and to test whether a similar pattern of response would hold for bovine enamel. STUDY DESIGN: Ninety-six enamel slabs (2 × 2 × 4 mm) (48 from bovine and 48 from human teeth) were randomly distributed according to surface treatment (n = 12): CO(2) laser, 5% sodium fluoride varnish (FV), 1.23% acidulated phosphate fluoride (APF) gel, or no treatment (control). Specimens were subjected to a 14-day in vitro cariogenic challenge. Microhardness (SMH) was measured at 30 µm from the surface. For ultrastructural analysis, additional 20 slabs of each substrate (n = 5) received the same treatment described earlier and were analyzed by SEM. RESULTS: ANOVA and Tukey test ascertained that CO(2) laser promoted the least mineral loss (SMH = 252(a)). Treatment with FV resulted in the second highest values (207(b)), which was followed by APF (172(c)). Untreated specimens performed the worst (154(d)). SEM showed no qualitative difference between human and bovine teeth. APF and control groups exhibited surfaces covered by the smear layer. A granulate precipitate were verified on FV group and fusion of enamel crystals were observed on lased-specimens. CONCLUSIONS: CO(2) laser may control caries progression more efficiently than fluoride sources and bovine teeth may be a suitable substitute for human teeth in studies of this nature.

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.

Ultrastructural analysis of radicular dentine surface submitted to CO2 laser at different parameters.

BACKGROUND: There are no reported studies comparing different parameter settings of the CO(2) laser and irradiation direction considering their effect on the morphology of radicular dentine surface. PURPOSE: To evaluate the alterations of radicular dentine (cervical, middle, and apical thirds) irradiated with CO(2) laser at different potencies and irradiation directions. STUDY DESIGN: Roots of 35 canines were prepared and randomly distributed according to the laser potency: GI: no laser treatment (control) (n = 5); GII, 2 W (n = 10); GIII: 4 W (n = 10); GIV: 6 W (n = 10). Each group (excepting GI) was divided in two subgroups according to the irradiation distance (n = 5): (A) parallel and (B) perpendicular to the root canal walls. The roots were splited longitudinally and analyzed by scanning electron microscopy in a qualiquatitative way. The scores were submitted to Kruskal-Wallis and Dunn's tests. RESULTS: No significant statistical differences were observed among root canal thirds (P > 0.05). The specimens irradiated with 2 W were statistically different (P < 0.05) from those irradiated with 4 and 6 W, which were statistically similar between themselves (P > 0.05). With 2, 4, and 6 W at in parallel irradiation and 2 W in perpendicular direction, the surface showed a fissured aspect. With 4 W in perpendicular direction and 6 W in parallel and perpendicular direction, surface was modified by laser action and exhibited fused areas. CONCLUSIONS: The intensity of the effects is dependent on the laser-irradiation dosimetries. Alterations were more intense when higher parameters were used.

SEM analysis of enamel surface treated by Er:YAG laser: influence of irradiation distance.

BACKGROUND: Depending on the distance of laser tip to dental surface a specific morphological pattern should be expected. However, there have been limited reports that correlate the Er:YAG irradiation distance with dental morphology. PURPOSE: To assess the influence of Er:YAG laser irradiation distance on enamel morphology, by means of scanning electron microscopy (SEM). METHODS: Sixty human third molars were employed to obtain discs (approximately =1 mm thick) that were randomly assigned to six groups (n=10). Five groups received Er:YAG laser irradiation (80 mJ/2 Hz) for 20 s, according to the irradiation distance: 11, 12, 14, 16, or 17 mm and the control group was treated with 37% phosphoric acid for 15 s. The laser-irradiated discs were bisected. One hemi-disc was separated for superficial analysis without subsequent acid etching, and the other one, received the phosphoric acid for 15 s. Samples were prepared for SEM. RESULTS: Laser irradiation at 11 and 12 mm provided an evident ablation of enamel, with evident fissures and some fused areas. At 14, 16 and 17 mm the superficial topography was flatter than in the other distances. The subsequent acid etching on the lased-surface partially removed the disorganized tissue. CONCLUSIONS: Er:YAG laser in defocused mode promoted slight morphological alterations and seems more suitable for enamel conditioning than focused irradiation. The application of phosphoric acid on lased-enamel surface, regardless of the irradiation distance, decreased the superficial irregularities.

Validity and reproducibility of different combinations of methods for occlusal caries detection: an in vitro comparison.

This study assessed the validity and reproducibility of different combinations of occlusal caries detection methods: visual examination (VE), laser fluorescence (LF) and radiographic examination (RE). Intra- and interexaminer reproducibilities were also assessed. Forty-seven extracted human molars were used and 121 sites, either suspected or not to be carious, were chosen. Occlusal surfaces were examined by 8 volunteers, assigned to three groups according to their level of knowledge and clinical experience on dental practice: group I, undergraduate students; group II, postgraduate students; group III, professors. Three combinations of methods were tested: A: VE+LF, B: VE+RE, C: VE+LF+RE. The examiners scored the sites using ranking scales and chose a final score based on their clinical experience. The gold standard was determined by histological examination of the sites. In general, LF and RE yielded poorer results than the combinations of methods. For combination A, group III showed the highest sensitivity, while group II showed the highest specificity. For combination B, group II showed moderate sensitivity whereas groups I and III exhibited low sensitivities; all groups of examiners reached substantial specificity. For combination C, all groups exhibited moderate sensitivity and substantial specificity. Interexaminer reproducibility ranged from fair to moderate for combinations A and C, while for combination B kappa values indicated moderate interexaminer reproducibility. It may be concluded that individual exams presented inferior performance than the conjunction of them. Combination C (VE+LF+RE) resulted in the best accuracy for all groups. The knowledge background of the examiners influenced their ability to detect caries lesions and affected interexaminer reproducibility.