The influence of thickeners of food on the particle size of boluses: a consideration for swallowing Abstract The purpose of this study was to examine the influence of thickeners with different levels of thickness on the sizes of particles in food boluses. In medical and nursing care, thickeners are used to make food safe for patients with dysphagia. However, the effect of thickeners on the foods they are added to, especially during swallowing, is still unclear. The bolus particles of 20 healthy volunteers were photographed, and the digital images were used to estimate the sizes of particles in them. Eight test samples with thickeners with different levels of thickness were tested: six grades of thickened carrot juice with raw carrots in it, raw carrot with banana, and raw carrot alone. The particle homogeneity index (HI) and particle size index (SI) just before swallowing were calculated. The viscosities of the liquid part of the test samples were also measured. The number of mastication cycles across the test samples was not significantly different. However, significant differences were found in SI and HI across the test samples: the absolute values of SI and HI tended to rise as the thickness of the test sample increased. The viscosity of the liquid part of the test sample also increased as the thickness increased. The differences in the thickness of food had an influence on the bolus particle sizes just before swallowing.

Fatigue resistance of monolithic lithium disilicate occlusal veneers: a pilot study Abstract The use of thin lithium disilicate (LD) occlusal veneers is an effective method to increase the vertical dimension of occlusion in cases of tooth wear. However, doubt remains regarding the threshold thickness to be used in this restoration class. This study aims to evaluate the effect of ceramic thickness on the survival rate and failure pattern of LD molar veneer restorations using a simplified fatigue testing machine. Sixty sound, freshly extracted human molars were used. Three groups (n = 20) were randomly created with different ceramic thicknesses (0.5, 0.8, and 1.2 mm), and 60 LD IPS e.max Press LT occlusal veneers were fabricated. The ceramic restorations were luted with a resin cement. The stainless-steel rotating drum of the ball mill contained 10 zirconia (Y-TZP) and 10 stainless steel spheres, in 500 mL of distilled water at 37 ± 1 °C. Crack growth in the LD restorations was evaluated under a stereomicroscope following each fatigue testing run (12 60-min runs). Progressive damage was observed as a function of cycling time. Survival was significantly influenced by the restoration thickness (p = 0.002, log-rank test), with thicker restorations exhibiting a higher survival rate. Thinner restorations (0.5 mm) showed significantly lower survival rate than 0.8- and 1.2-mm restorations (p < 0.016); no significant difference was observed between the 0.8- and 1.2-mm restorations. A threshold value of 0.8 mm may represent an acceptable compromise between fatigue resistance and tooth reduction.

Dual Rinse ® HEDP increases the surface tension of NaOCl but may increase its dentin disinfection efficacy Abstract The aim of this study was to evaluate the surface tension and the antimicrobial activity in infected dentin of a NaOCl solution combined with an etidronate powder (Dual Rinse® HEDP), compared to pure NaOCl and the classic NaOCl + EDTA irrigating sequence, respectively. The surface tension of three irrigants was measured by Wilhelmy technique. To evaluate the antimicrobial activity of the solutions, 26 human teeth were contaminated for 5 days with E. faecalis. After bacterial contamination, ten samples were irrigated with NaOCl followed by EDTA, another ten with NaOCl/Dual Rinse® HEDP, and four were used as positive controls. Two specimens not contaminated were used as negative controls. After live/dead BacLight staining, samples were examined by CLSM for analyzing % of residual live and dead cells. Comparison of bacterial viability between and within groups was performed using the Mann–Whitney test for independent samples and the Wilcoxon signed-rank test, respectively. The mean surface tension of EDTA was significantly lower than that of the other irrigants tested (p < 0.001). Conversely, the surface tension of NaOCl/Dual Rinse® HEDP solution was significantly higher than that of all the other solutions (p < 0.001). Residual bacterial viability in the NaOCl/Dual Rinse® HEDP (1.71%) was significantly lower (p = 0.019) than in the NaOCl + EDTA group (3.77%). All of the experimental groups showed significantly lower proportion of viable bacterial cells than the positive control group (p < 0.01). Clinical relevance adding etidronate to NaOCl increases its antimicrobial effect in dentinal tubules even though increases its surface tension.

Surface nanoscale profile of WaveOne, WaveOne Gold, Reciproc, and Reciproc blue, before and after root canal preparation Abstract This study aimed to compare the surface topographies and nanoscale profiles of intact and used WaveOne, WaveOne Gold, Reciproc, and Reciproc blue nickel–titanium (NiTi) instruments. Sixteen NiTi instruments were evaluated; four from each one of WaveOne (25/0.08), WaveOne Gold (25/0.07), Reciproc (25/0.08), and Reciproc blue (25/0.08) files. Each instrument was used to prepare four curved canals. A three-dimensional nanoscale surface profiler was used to assess instrument surfaces before and after root canal instrumentation. The data were analyzed with one-way analysis of variance using SPSS 21.0 software and set significance at P < 0.05. There were significant differences in surface topography between NiTi instruments. Intact WaveOne and WaveOne Gold instruments had the highest values, followed by the Reciproc and Reciproc blue instruments (P < 0.05). Used WaveOne and WaveOne Gold instruments had the highest values, followed by Reciproc and Reciproc blue instruments (P < 0.05). Some indications of microcracks in qualitatively intact Reciproc blue files were observed, and minor surface cracks in used WaveOne Gold instruments were also observed. Used WaveOne, Reciproc, and Reciproc blue instruments exhibited cracks and microcavities. WaveOne Gold and Reciproc blue instruments had significantly higher levels of surface distortion after root canal instrumentation, and WaveOne exhibited the lowest level of surface deformation. Each of the Reciprocating instruments was safely used to prepare four canals without incident. The three-dimensional stylus profiler provided valuable assessments of the surface topographies of NiTi instruments.

Effects of metabolic syndrome on jawbones and bone metabolic markers in sucrose-fed rats Abstract The aim of this study was to investigate the effects of metabolic syndrome (MetS) on bone mineral density (BMD) and microstructure of jawbones, and circulating bone metabolic markers. MetS was induced in male Wistar rats by a 16-week high-sucrose drinking water diet. Mandibles were analyzed for BMD and microstructure by standard radiographs and X-ray diffraction. BMD of three different regions of mandible in MetS group was significantly lower compared to control group. The diffraction intensity of mandibular bone in MetS group was significantly decreased (8.2%) compared to control group; however, crystallite radiuses of mandibular bone samples in both groups were not significantly different. In MetS group, serum bone-specific tartrate-resistant acid phosphatase-5b (TRACP-5b) activity was significantly increased (47%), whereas bone-specific alkaline phosphatase (BALP) activity was significantly decreased (44%) compared to control group. The serum magnesium level in MetS rats (1.82 ± 0.27 mg dL−1) was lower than that of controls (2.11 ± 0.16 mg dL−1). Rats with MetS had significantly higher serum calcium level (9.70 ± 0.41 mg dL−1) than the controls (9.21 ± 0.50 mg dL−1). Overall data suggested that MetS is associated with a significant decrease in BMD and slight deterioration in microcrystallite structure of the jawbones. The changes in TRACP-5b and BALP activities and serum Ca2+ and Mg2+ concentrations also support these findings at a biochemical level.

Review: modulation of the oral microbiome by the host to promote ecological balance Abstract The indivisible relationship between the human host and its oral microbiome has been shaped throughout the millennia, by facing various changes that have forced the adaptation of oral microorganisms to new environmental conditions. In this constant crosstalk between the human host and its microbiome, a bidirectional relationship has been established. The microorganisms provide the host with functions it cannot perform on its own and at the same time the host provides its microbes with a suitable environment for their growth and development. These host factors can positively affect the microbiome, promoting diversity and balance between different species, resulting in a state of symbiosis and absence of pathology. In contrast, other host factors can negatively influence the composition of the oral microbiome and drive the interaction towards a dysbiotic state, where the balance tilts towards a harmful relationship between the host and its microbiome. The aim of this review is to describe the role host factors play in cultivating and maintaining a healthy oral ecology and discuss mechanisms that can prevent its drift towards dysbiosis.

Effects of intracoronal bleaching agents on the surface properties of mineral trioxide aggregate Abstract Bleaching agents may affect surface properties of mineral trioxide aggregate (MTA) as a coronal barrier. The purpose of this study was to investigate surface properties of MTA after exposure to intracoronal bleaching agents. MTA was set in acrylic molds with a 4 mm high central hole and a 6 mm diameter. Specimens were divided into four groups (n = 10); three groups were exposed to bleaching agents three times on every fourth day (carbamide peroxide—CP, hydrogen peroxide—HP, sodium perborate—SP) and a control group—C. The surface roughness and Vickers surface microhardness were measured. Differences between groups were analyzed using a Kruskal–Wallis test and intergroup comparisons were assessed with a Mann–Whitney U test with a Bonferroni correction (p < 0.0001). The microstructure and elemental composition were observed using a scanning electron microscope (SEM) and an energy-dispersive X-ray microanalysis (EDX) system. In terms of microhardness, the decrease in the HP group was significantly greater than that of the CP and SP groups; CP group significantly greater than that of the SP group, however, there was no significant difference between the SP and C groups. Surface roughness values were compared between groups, and no significant differences were observed between the CP and HP groups, and they exhibited significantly higher roughness values than the SP and C groups. SEM/EDX showed that the bleaching agents affected the elemental distribution. Bleaching agents adversely affected the surface roughness, surface microhardness and elemental distribution of MTA, with exposure to SP causing fewer changes on the surface properties than CP or HP.

Hydroxyapatite coating effect on the bond strength between CAD/CAM materials and a resin cement Abstract The purpose of this study was to evaluate the bond strength between CAD/CAM materials and a resin cement using hydroxyapatite coating as a surface treatment method. Different surface treatments (Control, no treatment-C; Sandblasting-SB; Hydrofluoric acid etching-HF; applying tooth desensitizer-TeM; applying topical crème-ToM, HAp coating with Pulse Laser Deposition technique-PLD) were applied to three different CAD/CAM materials (LAVA Ultimate, VITA Enamic, and Cerec Blocs). After surface treatments, a universal adhesive (Single Bond Universal, 3M ESPE) was applied and adhesive resin (Rely X Ultimate, 3M ESPE) were cemented on each material surface using plastic tubes (4 mm in diameter). The shear bond strength values were measured using a universal testing machine. Scanning electron microscope analysis were performed to evaluate failure modes and effects of surface treatments. Obtained data were statistically analyzed using two-way ANOVA and Tukey’s post hoc test (p = 0.05). The bond strength of PLD groups were significantly higher than other groups in resin-ceramics (p < 0.05). In Cerec Blocs, HF resulted significantly higher bond strength than other groups (p < 0.05). SEM analysis of surface treatment methods (except TeM and ToM) revealed an increase in surface alterations compared to control groups. Failure modes were dominantly adhesive in groups C, TeM, and ToM, whereas mostly mix or cohesive failures were observed in PLD, HF, and SB. Hydroxyapatite coating with PLD technique exhibited promising bond strength results for CAD/CAM resin-ceramics. HAp coating can be used as a replacement for hydrofluoric acid etching and sandblasting in CAD/CAM resin-ceramic materials to obtain better bond strength values.

Comparison of the antibacterial activity of calcium silicate- and epoxy resin-based endodontic sealers against Enterococcus faecalis biofilms: a confocal laser-scanning microscopy analysis Abstract This study assessed the antibacterial activity of BioRoot RCS in comparison with that of the Totalfill BC and AH Plus sealers against Enterococcus faecalis biofilms in dentinal tubules using confocal laser-scanning microscopy. Sixty-six root dentin halves were prepared and sterilized. Three sections were used to ensure sterilization. The remaining were inoculated with E. faecalis. Three specimens were examined to verify the viability of biofilms. The sixty specimens were randomly divided into four groups: AH Plus, BioRoot RCS, Totalfill BC sealer, and no sealer. The specimens were incubated for 1, 7, and 30 days. The specimens were stained and four corners of each disc were scanned. Statistical analysis was performed using two-way ANOVA and Tukey’s post hoc test. Almost half of the bacteria were dead in BioRoot RCS group on day 1 and in Totalfill BC group on day 7. All sealers killed significantly more bacteria than the control after 30 days (P < .05). On day 7, Totalfill BC showed a significantly higher percentage of dead bacteria than BioRoot RCS (P < .05). On day 30, the BioRoot RCS group registered the highest percentage of dead cells (61.75%), which was significantly higher than the percentages of the AH Plus and Totalfill BC groups (P < .05). Calcium silicate-based root canal sealers exerted antimicrobial effects against E. faecalis biofilms. The antibacterial activity of BioRoot RCS was significantly higher than that of the Totalfill BC and AH Plus sealers after 30 days of exposure.

Self-reported periodontitis and migraine: results from a multicenter, cross-sectional survey in Spain Abstract The aim of this study was to evaluate self-reported periodontitis (PD) prevalence in migraineurs as well as to investigate the association between both diseases. A cross-sectional survey was carried out including patients diagnosed with migraine attending 12 Spanish Headache Units. We determined diagnosis of PD administering a validated self-reported questionnaire. Socio-demographic, clinical and medical information, comorbidities, daily habits, migraine characteristics and medication were collected using a questionnaire. Of the 651 consecutive migraineurs included in the study, 393 suffered from chronic migraine (CM). Self-reported PD was detected in 327 patients with migraine (50.2%). Migraineurs with self-reported PD were significantly older and had a previous history of fibromyalgia, stress, anxiety, depression, and allodynia (all P < 0.001). Additionally, this group of patients consumed more topiramate (P = 0.008) and simple analgesics (P < 0.001) than patients with migraine and without self-reported PD. Also, they were less active physically and belonged to a low education level (both P < 0.001). Prevalence of self-reported PD was significantly higher in chronic migraineurs compared to those diagnosed with episodic migraine (EM) (53.9% vs. 44.6%, P = 0.019). Logistic regression analyses showed that self-reported PD was associated with CM (OR 1.456; 95% CI 1.062–1.997, P = 0.020). However, after adjusting for significant confounders, the association was attenuated (OR 1.100; 95% CI 0.784–1.543, P = 0.581). We concluded that self-reported PD was significantly more frequent in CM compared to EM. Self-reported PD was associated with the presence of CM, although some comorbidities shared by both diseases could have an effect on this association.