Intrapulpal Concentration of Hydrogen Peroxide of Teeth Restored With Bulk Fill and Conventional Bioactive Composites.

This study evaluated intrapulpal concentration and hydrogen peroxide (HP) penetration at the interface of teeth restored with bioactive composites, using conventional or bulk-fill composites. Cylindrical cavities were prepared on the buccal surface of bovine incisor crowns (n=20) and restored with: resin modified glass-ionomer (RMGI, Riva Light Cure, SDI), non-bioactive bulk-fill composite (FB, Filtek Bulk, 3M Oral Care), non-bioactive conventional composite (FZ, Filtek Z350, 3M Oral Care), bioactive bulk-fill composite (AC, Activa BioActive, Pulpedent), and bioactive conventional composite (BII, Beautifil II, Shofu). After 5,000 thermal cycles, restorations (n=10) were exposed to high (35% HP [4 applications of 8 min/session-4 sessions]) or low (9.5% HP [30 min/day-14 days]) concentration bleaching protocols. After the last bleaching application, the HP intrapulpal concentration was determined. Additional teeth were restored, pigmented with rhodamine B solution, and HP penetration around the interface was observed under laser scanning confocal fluorescence microscopy (LSCFM, n=3). The presence of gaps at the interface was observed on replicas of the cross-sectioned samples under scanning electron microscopy (SEM, n=5). Data were submitted to one-way (gap analysis) and twoway analysis of variance (ANOVA; HP intrapulpal concentration) and Tukey test (α=0.05). The LSCFM images were qualitatively analyzed. The restored teeth submitted to 35% HP presented higher HP intrapulpal concentration than teeth submitted to 9.5% HP (p<0.05). No differences in HP intrapulpal concentration was observed among groups (p>0.05) when exposed to 9.5% HP. Lower HP intrapulpal concentration was observed for teeth restored with RMGI exposed to HP 35%, when compared with teeth restored with nonbioactive conventional (FZ; p=0.004) and bulk-fill composites (FB; p=0.01). No gap formation was observed at the outer enamel adhesive interface for all restorative materials. LSCFM images showed that 35% HP promoted greater degradation of rhodamine B at the enamel, except for RMGI. In this context, RMGI promoted lower HP intrapulpal concentration than non-bioactive conventional and bulk-fill composites.

Stress distribution and displacement of three different types of micro-implant assisted rapid maxillary expansion (MARME): a three-dimensional finite element study.

BACKGROUND/OBJECTIVE: Until 2010, adults underwent surgical treatment for maxillary expansion; however, with the advent of micro-implant-assisted rapid maxillary expansion (MARME), the availability of less invasive treatment options has increased. Nevertheless, individuals with severe transverse maxillary deficiency do not benefit from this therapy. This has aroused interest in creating a new device that allows the benefit of maxillary expansion for these individuals. The aim of this study was to evaluate the efficacy of three MARME models according to tension points, force distribution, and areas of concentration in the craniofacial complex when transverse forces are applied using finite element analysis. MATERIALS AND METHODS: Digital modeling of the three MARME models was performed. Model A comprised five components: one body screw expander and four adjustable arms with rings for mini-implant insertion. These arms have an individualized height adjustment that allows MARME positioning according to the patient's palatal anatomy, thereby preventing body screw expander collision with the lateral mucosa in severe cases of maxillary deficiency. Model B was a maxillary expander with screw rings joined to the body, and model C was similar to model B, except that model C had open rings for the insertion of the mini-implants. Through the MEF (Ansys software), the stresses, distribution, and area of concentration of the stresses were evaluated when transverse forces of 7.85 N were applied. RESULTS: The three models maintained the following pattern: model C presented weak stress peaks with limited distribution and lower concentration area, model B obtained median stress peaks with better distribution when compared to that of model C, and model A showed better stress distribution and larger concentration area. In model A, tensions were located in the lateral lamina of the pterygoid process, which is an important site for maxillary expansion. The limitation of the present study was that it did not include the periodontal tissues and muscles in the finite element method evaluation. CONCLUSIONS: Model A showed the best stress distribution conditions. In cases of severe atresia, model A seems to be an excellent option.

In Vitro Evaluation of Surface Properties and Wear Resistance of Conventional and Bulk-fill Resin-based Composites After Brushing With a Dentifrice.

OBJECTIVES: This study evaluated the effect of toothbrushing with a dentifrice on gloss, roughness profile, surface roughness, and wear of conventional and bulk-fill resin-based composites. METHODS AND MATERIALS: Gloss and surface roughness of resin-based composites (RBCs; Admira Fusion X-tra, Aura Bulk Fill, Filtek Bulk Fill Flowable, Filtek Bulk Fill Posterior Restorative, Filtek Supreme Ultra, Herculite Ultra, Mosaic Enamel, SDR flow+, Sonic Fill 2, Tetric EvoFlow Bulk Fill and Tetric EvoCeram Bulk Fill) were analyzed before and after brushing; the roughness profile and wear were also determined after toothbrushing. Representative three-dimensional images of the surface loss and images comparing the unbrushed and brushed surfaces were also compared. Analysis of variance and Tukey post hoc tests were applied (α=0.05) to the gloss, surface roughness, roughness profile, and surface loss data. Pearson's correlation test was used to determine the correlation between gloss and surface roughness, surface loss and percentage of gloss decrease after brushing, and surface loss and surface roughness after brushing. RESULTS: For all RBCs tested after 20,000 brushing cycles, the gloss was reduced and the surface roughness increased (p<0.05). However, the roughness profile and the amount of surface loss were dependent on the RBC brand. Admira Fusion X-tra, Aura, Tetric EvoCeram Bulk Fill, and Tetric EvoFlow Bulk Fill showed the deepest areas of wear (p<0.05). A significant negative correlation was found between gloss and surface roughness, and a weak correlation was found between the decrease in gloss and the extent of surface loss, and any increase in surface roughness and the surface loss. CONCLUSIONS: Toothbrushing with a dentifrice reduced the gloss, increased the surface roughness, and caused loss at the surface of all the RBCs tested. Considering all the properties tested, Mosaic Enamel exhibited excellent gloss retention and a low roughness profile and wear, while Admira Fusion X-tra exhibited the greatest decrease in gloss, the highest roughness profile, and the most wear.

Stability of the Light Output, Oral Cavity Tip Accessibility in Posterior Region and Emission Spectrum of Light-Curing Units.

OBJECTIVES: This study evaluated the light output from six light-emitting diode dental curing lights after 25 consecutive light exposures without recharging the battery, tip accessibility in the posterior region, and light beam spread from light-curing units. METHODS: Irradiance, spectral peak, and radiant exposure were measured with the battery fully charged (Bluephase Style, ESPE Cordless, Elipar S10, Demi Ultra, Valo Cordless, and Radii-Cal) and monitored for 25 light exposures (each lasting 10 seconds). The tip diameter was measured to identify the beam size and the ability of the six light-curing units to irradiate all areas of the lower second molar in the standard output setting. RESULTS: Four curing lights delivered a single peak wavelength from 454 to 462 nm, and two (Bluephase Style and Valo Cordless) delivered multiple emission peaks (at 410 and 458 nm and 400, 450, and 460 nm, respectively). The irradiance and radiant exposure always decreased after 25 exposures by 2% to 8%, depending on the light unit; however, only ESPE Cordless, Valo Cordless, and Radii-Cal presented a statistical difference between the first and the last exposure. The tip diameter ranged from 6.77 mm to 9.40 mm. The Radii-Cal delivered the lowest radiant exposure and irradiance. This light was also unable to access all the teeth with the tip parallel to the occlusal surface of the tooth. CONCLUSION: Not all of the blue-emitting lights deliver the same emission spectra, and some curing lights delivered a lower irradiance (as much as 8% lower) after the 25th exposure.

Effect of Storage Time on Bond Strength Performance of Multimode Adhesives to Indirect Resin Composite and Lithium Disilicate Glass Ceramic.

PURPOSE: To investigate the bond strength performance of multimode adhesives (MMAs) to indirect resin composite and lithium disilicate glass ceramic after 24 hours or one year of water storage. METHODS AND MATERIALS: Thirty flat and polished plates of indirect resin composite (Epricord) and thirty lithium disilicate glass ceramic plates (IPS e.max Press) were prepared. Surfaces were pretreated using sandblasting (indirect resin composite) or hydrofluoric acid (glass-based ceramic). Specimens were bonded with one of two MMAs (Scotchbond Universal [SBU] or All-Bond Universal [ABU]) or ceramic primer and hydrophobic bonding (RelyX Ceramic Primer and Adper Scotchbond Multi-Purpose Bond) as a control (n=10). Resin cement cylinders (0.75 mm in diameter × 0.5 mm in height) were bonded to both substrate surfaces using the respective adhesives. After 24 hours or one year of water storage, bonding performance was measured by microshear bond strength (MSBS) testing. Results were analyzed using three-way ANOVA with Bonferroni post hoc tests (α=0.05). RESULTS: For indirect resin composite, significantly higher MSBS values were found for ABU after 24 hours (ABU > SBU = control); however, no significant difference among the adhesives was observed after one year (p>0.05). For glass-based ceramic, significantly different bond strengths were observed among the adhesives after 24 hours (control = ABU > SBU) and one year (control > SBU = ABU; p<0.05). CONCLUSIONS: Both MMAs tested can be considered effective alternatives for bonding to sandblasted indirect resin composite after aging, as they showed similar bond performance to that of the control group. However, separate bottles of silane bonding resin showed higher MSBS values and more durable bonding for etched glass-based ceramic.

Effect of Storage Time on Bond Strength and Nanoleakage Expression of Universal Adhesives Bonded to Dentin and Etched Enamel.

PURPOSE: To investigate bond strength and nanoleakage expression of universal adhesives (UA) bonded to dentin and etched enamel. METHODS: Extracted human third molars were sectioned and ground to obtain flat surfaces of dentin (n = 36) and enamel (n = 48). Dentin and etched enamel surfaces were bonded with one of two UAs, All-Bond Universal (ABU) or Scotchbond Universal (SBU); or a two-step self-etching adhesive, Clearfil SE Bond (CSEB). A hydrophobic bonding resin, Adper Scotchbond Multi-Purpose Bond (ASMP Bond) was applied only on etched enamel. Following each bonding procedure, resin composite blocks were built up incrementally. The specimens were sectioned and subjected to microtensile bond strength (MTBS) testing after 24 hours or one year water storage, or immersed into ammoniacal silver nitrate solution after aging with 10,000 thermocycles and observed using scanning electron microscopy. The percentage distribution of silver particles at the adhesive/tooth interface was calculated using digital image-analysis software. RESULTS: The MTBS (CSEB = SBU > ABU, for dentin; and CSEB > ABU = SBU = ASMP Bond, for etched enamel) differed significantly between the adhesives after 24 hours. After one year, MTBS values were reduced significantly within the same adhesive for both substrates (analysis of variance, Bonferroni post hoc, p<0.05), and no significant differences were found among the adhesives for etched enamel. Silver particles could be detected within the adhesive/dentin interface of all specimens tested. Kruskal-Wallis mean ranks for nanoleakage in ABU, SBU, and CSEB were 16.9, 18.5 and 11, respectively (p>0.05). CONCLUSIONS: In the short term, MTBS values were material and dental-substrate dependent. After aging, a decrease in bonding effectiveness was observed in all materials, with nanoleakage at the adhesive/dentin interface. The bonding of the UAs was equal or inferior to that of the conventional restorative systems when applied to either substrate and after either storage period.

Pacemaker endocarditis caused by Propionibacterium acnes in an adult patient with Ebstein's anomaly: a report of a rare case.

We report a rare case of a Brazilian adult woman with Ebstein's Anomaly who presented with pacemaker endocarditis caused by Propionibacterium acnes. Ebstein's Anomaly is a rare congenital malformation of the heart. Infective endocarditis is defined as an infection of heart valves, of the mural endocardium, of a septal defect, or of a cardiac electronic implantable device. Propionibacterium acnes is a skin commensal bacterium, that is usually considered as a contaminant, but can, on rare occasions, cause serious infections including endocarditis of prosthetic valves, native valves and cardiac electronic implantable devices. Diagnosis was made after nearly two years of investigation by identification of the organism by the MALDI-TOF technique and transoesophageal echocardiogram. The patient was successfully treated with daptomycin and device removal. She remains free of endocarditis after 32 months of follow-up.

Photoinduced deprotection and ZnO patterning of hydroxyl-terminated siloxane-based monolayers.

Trimethoxy-[11-(2-nitrobenzyloxy)undecyl]silane (1) and trimethoxy-[17-(2-nitrobenzyloxy)heptadecyl]silane (2) have been used for the covalent assembly of siloxane-based photopatternable monolayers. Exposing the monolayers to UV light (312 +/- 10 nm) results in the generation of reactive hydroxyl-terminated monolayers without affecting the film quality. The new monolayers, deprotection chemistry, and the effect of photoinduced headgroup lift-off on the monolayer microstructure have been studied in detail by a full complement of physicochemical techniques, including optical (UV-vis) spectroscopy, ellipsometry, aqueous contact angle (CA) measurements, X-ray photoelectron spectroscopy (XPS), synchrotron X-ray reflectivity (XRR), and atomic force microscopy (AFM and AFM-force spectroscopy). AFM-force spectroscopy was used to analyze hydrogen-bond interactions as a function of the nature of the solid-liquid interface. AFM-force spectroscopy indicates a hydrogen-bond energy for photodeprotected monolayers of 8.2 kJ mol(-1) (approximately 2 kcal mol(-1)). Scanning electron microscopy (SEM) revealed that treatment of photopatterned monolayers with ZnEt2 solutions resulted in well-defined approximately 2 microm x 2 microm features of 10 A thick ZnO layers.

A computational foray into the formation and reactivity of metallabenzenes.

Various metallabenzene complexes, analogues of benzene where one CH unit has been replaced by an organometallic fragment, have been reported in the literature. A detailed theoretical investigation on the chemistry of these complexes is presented here. This includes an evaluation of their aromaticity, the mechanisms of formation of osmium, iridium, and platinum metallabenzene complexes, and one intriguing aspect of their chemistry, the formation of cyclopentadienyl (Cp) complexes. X-ray photoelectron spectroscopy (XPS) measurements on two osmabenzene examples are also presented. In addition, diffuse functions for use with the SDD and SDB-cc-pVDZ basis set-RECP combinations are presented for the transition metals.