Brazilian undergraduates' and dentists' knowledge on preventing, diagnosing and managing dentin hypersensitivity: A cross-sectional questionnaire study.

OBJECTIVES: To analyse the knowledge of dental undergraduates and dentists on the prevention, diagnosis and management of dentin hypersensitivity (DH); to compare their knowledge scores; and to understand the related variables using a regression model. METHODS: An original online questionnaire investigated the attitudes, self-reported knowledge ('how much they thought they knew') and real knowledge ('how much they really knew') of 132 students and 338 dentists. Data were analysed descriptively, both knowledge scores were compared using Mann-Whitney and Wilcoxon signed-rank tests and data were subjected to two multiple linear regression analyses considering real knowledge scores as the dependent variable (α < 0.05). RESULTS: The self-reported knowledge on DH was higher than the real knowledge for both students and dentists, but dentists presented the highest scores. Gingival recession and acidic diet were reported as the main predisposing factors for DH by undergraduates and dentists. Students normally managed DH with dietary and hygiene instructions followed by a desensitizing agent application, while dentists managed with occlusal adjustments. The mechanism of glutaraldehyde/HEMA and bioactive fillers on DH is widely unknown by students and dentists. The majority of the questioned individuals cannot differentiate DH from sensitivity of caries or molar-incisor hypomineralization. CONCLUSION: Both students and dentists overestimate their knowledge of DH, revealing deficiencies in prevention, diagnosis and management. Students' knowledge improves towards the end of the Dentistry course, while younger dentists and PhD holders are more knowledgeable. Institutions should implement ongoing DH education for undergraduates and conduct interventions for experienced professionals, especially older ones.

Analysis of color stability and degree of conversion of different types of resin composites.

Resin composites containing surface pre-reacted glass (S-PRG) have been introduced to reduce demineralization and improve remineralization of the tooth structure. However, water diffusion within the material is necessary for its action, which can impair its overall physicomechanical properties over time, including color stability. This study aimed to evaluate the color stability and related degree of conversion (DC) of four resin composites. Discs (6 x 4 mm, n = 5/group) of microhybrid (MH), nanofilled (NF), nanohybrid (NH), and S-PRG-based nanohybrid (S-PRG-NH) composites with two opacities (A2/A2E and A2O/A2D) were prepared. Color (CIELab and CIEDE2000) was evaluated with a spectrophotometer after aging in grape juice (2 x 10 min/10mL/7days). The DC was analyzed by using Fourier transform infrared spectroscopy before and after light-curing. Data were statistically analyzed by using two-way analysis of variance and post-hoc least significant difference tests (p<0.05). In the color stability analysis, the interaction between filler type and opacity was significant (CIELab, p = 0.0015; CIEDE2000, p = 0.0026). NH presented the highest color stability, which did not differ from that of MH. The greatest color alteration was observed for S-PRG-NH. S-PRG fillers also influenced DC (p < 0.05). The nanohybrid resin composite presented favorable overall performance, which is likely related to its more stable organic content. Notwithstanding the benefits of using S-PRG-based nanohybrid resins, mostly in aesthetic procedures, professionals should consider the susceptibility of such resins to color alteration, probably due to the water-based bioactive mechanism of action.

Analysis of color stability and degree of conversion of different types of resin composites

Abstract Resin composites containing surface pre-reacted glass (S-PRG) have been introduced to reduce demineralization and improve remineralization of the tooth structure. However, water diffusion within the material is necessary for its action, which can impair its overall physicomechanical properties over time, including color stability. This study aimed to evaluate the color stability and related degree of conversion (DC) of four resin composites. Discs (6 x 4 mm, n = 5/group) of microhybrid (MH), nanofilled (NF), nanohybrid (NH), and S-PRG-based nanohybrid (S-PRG-NH) composites with two opacities (A2/A2E and A2O/A2D) were prepared. Color (CIELab and CIEDE2000) was evaluated with a spectrophotometer after aging in grape juice (2 x 10 min/10mL/7days). The DC was analyzed by using Fourier transform infrared spectroscopy before and after light-curing. Data were statistically analyzed by using two-way analysis of variance and post-hoc least significant difference tests (p<0.05). In the color stability analysis, the interaction between filler type and opacity was significant (CIELab, p = 0.0015; CIEDE2000, p = 0.0026). NH presented the highest color stability, which did not differ from that of MH. The greatest color alteration was observed for S-PRG-NH. S-PRG fillers also influenced DC (p < 0.05). The nanohybrid resin composite presented favorable overall performance, which is likely related to its more stable organic content. Notwithstanding the benefits of using S-PRG-based nanohybrid resins, mostly in aesthetic procedures, professionals should consider the susceptibility of such resins to color alteration, probably due to the water-based bioactive mechanism of action.

Comparison of the Metabolic Profile between Unstimulated and Stimulated Saliva Samples from Pregnant Women with/without Obesity and Periodontitis.

This study aimed to compare the metabolic profile of unstimulated (US) and stimulated (SS) saliva samples from pregnant women with/without obesity and periodontitis. Ninety-six pregnant women were divided into: obesity + periodontitis (OP = 20); obesity/no periodontitis (OWP = 27); normal BMI + periodontitis (NP = 20); and normal BMI/no periodontitis (NWP = 29). US and SS samples were collected by expectoration and chewing of sterilized parafilm gum, respectively, and samples were individually analyzed by Proton Nuclear Magnetic Resonance (1H-NMR). Univariate (t test and correlations) and multivariate (Principal Component Analysis-PCA, and Partial Least Square-Discriminant Analysis-PLS-DA with Variance Importance Projection-VIP scores) and Metabolite Set Enrichment Analysis were done (p < 0.05). Metabolites commonly found in all groups in elevated concentration in US samples were 5-Aminopentoate, Acetic acid, Butyric acid, Propionic acid, Pyruvic acid, and Succinic acid. They were mainly related to the butyrate metabolism, citric acid cycle, amino sugar metabolism, fatty acids biosynthesis, pyruvate metabolism, glutamate metabolism, and Warburg effect. Metabolites commonly found in all groups that were in elevated concentration in SS samples were Citrulline, Fumaric acid, Histidine, N-acetyl glutamine, N-acetylneuraminic acid, para-hydroxyphenylacetic acid, Proline, Tyrosine. Although some differences were found between unstimulated and stimulated saliva samples from pregnant women with/without obesity and periodontitis, stimulated saliva collection seems adequate, demonstrating similar metabolic pathways to unstimulated saliva samples when groups are compared.

Solvation role of dimethyl sulfoxide on the interaction with dentin bonding systems after 30 months.

OBJECTIVES: To determine whether DMSO could serve as an effective pretreatment to improve the mechanical properties and minimize the degradation of the adhesive interface, through the degree of conversion (DC) and bond strength to dentin of different categories of dentin bonding systems (DBSs) after 30 months. METHODS: DMSO (0, 0.5, 1, 2, 5, 10 vol%) were incorporated into four categories of DBSs: Adper Scotchbond Multipurpose (MP), Adper Single Bond 2 (SB), Clearfil SE Bond (CSE) and Adper Scotchbond Universal (SU). DC was evaluated by Fourier transform infrared spectroscopy (FTIR). For microtensile bond strength test (µTBS), 1 % DMSO were applied on dentin as pretreatment before DBSs. For SU, both strategies were tested. Specimens for µTBS were tested after 24 h, 6 and 30 months. DC and µTBS data were subjected to two-way ANOVA and Tukey test (α < 0.05). RESULTS: Incorporating 5 %/10 % DMSO increased the DC of CSE. Controversially, when combined with SU, 2 % and 10 % DMSO jeopardized the DC. Regarding µTBS, 1 % DMSO pre-treatment increased the bond strength for MP, SB, SU-ER and SU-SE. After 30 months, MP, SU-ER and SU-SE showed a decrease compared to baseline but remained higher than the control. CLINICAL SIGNIFICANCE: DMSO pretreatment may be a useful strategy to improve the bond interface over time. Its incorporation seems to favor the non-solvated systems regarding DC while it seems to show long-term benefits for bond strength using 1 % DMSO for MP and SU systems.

The stamp technique for direct restoration in a ICDAS 4 carious lesion: A 4-year follow-up.

OBJECTIVE: This case report described the use of a stamping technique associated with a bulk fill composite to restore an ICDAS 4 carious lesion on a posterior tooth. The 4-year follow-up is also presented. CLINICAL CONSIDERATIONS: A 32-year-old patient presented a carious lesion on tooth 36 with an underlying dark shadow at the dentin seen from the noncavitated enamel occlusal surface, which was compatible with an ICDAS 4 carious lesion. The lesion was radiographically detected and the caries disease was treated with dietary and hygiene habits orientations. Before accessing the lesion and selectively removing the carious tissue, an occlusal stamp was made by applying a flowable resin composite to copy the anatomy of the noncavitated enamel surface. The cavity was restored using a bulk fill resin composite (Opus Bulk Fill, FGM) with 4-mm-thick increments. Before curing the last increment, a Teflon band was adapted at the uncured bulk fill composite surface and the occlusal stamp made with the flowable composite was pressed against it to reproduce the natural characteristics and initial occlusal anatomy. The top surface was light-activated for 40 s. After 4 years, small wear could be seen in the restoration, but still within clinically acceptable levels. CONCLUSION: The occlusal stamp technique allows reproduction of the natural anatomy of teeth affected by ICDAS 4 carious lesions with good clinical longevity over 4 years. CLINICAL SIGNIFICANCE: This case report presents the use of the stamp technique to restore a tooth affected by an ICDAS 4 lesion, in which a carious process reached the dentin and the enamel anatomy was still preserved. The bulk fill resin composite associated with the occlusal stamp was chosen to quickly restore the cavity with clinical predictability. Bulk fill composites allow the insertion of up to 4-mm-thick increments and offer lower shrinkage stress, good clinical longevity and a less time-consuming procedure in cases of posterior teeth, especially if associated with the stamp technique.

Knowledge and Attitudes on Preventing and Treating Dentin Hypersensitivity and Its Predicting Factors: A Cross-sectional Study with Brazilian Citizens.

OBJECTIVES: Most dental schools have included dentin hypersensitivity (DH) as part of their taught curriculum to educate undergraduates; however, it is possible that the public still does not recognize its symptoms and the factors that predispose to the onset of this condition. Thus, the aim of this study was to assess the knowledge of a Brazilian population regarding the prevention and treatment of DH and to identify what self-reported factors can serve as predictors of the frequency of DH. MATERIALS AND METHODS: An online questionnaire investigated the demographic characteristics, oral health self-perception and attitudes, and DH prevention and treatment measures of 226 participants. STATISTICAL ANALYSIS: Data were analyzed descriptively and by a multiple linear regression with DH frequency score as the dependent variable (α < 0.05). RESULTS: Total 61.1% of females (n = 138) and 38.9% of males (n = 88) (mean age: 35.1 ± 12.2 years) completed the questionnaire. The sample's mean DH frequency score (minimum 0; maximum 20) was 4.2 and classified as low, with 19.1% using desensitizing products and 22.1% reporting having noncarious cervical lesions (NCCLs). When experiencing DH episodes, 21.2% never and 30.1% rarely scheduled dental appointments. Regression analysis retrieved a significant final model (F [5,220] = 12.047; p < 0.001; R 2 = 0.215). CONCLUSION: This study identified that 36.7% and 18.6% of the sample were unaware that DH can be both prevented and treated, respectively. Moreover, the presence of NCCLs, frequency of daily toothbrushing, use of desensitizing products, presence of DH modulating factors, and the presence of parafunctional habits symptoms served as predictors of DH frequency.

Resin-based materials to control human dentin permeability under erosive conditions in vitro: A hydraulic conductance, confocal microscopy and FTIR study.

OBJECTIVES: To characterize the behavior of three different polymeric agents before and after an erosive challenge on dentin permeability, to analyze their degradation in both conditions, and to analyze their degree of conversion (DC). METHODS: The permeability of human dentin disks (1.0 ± 0.2 mm) was measured with smear layer, after its removal, after treatment (LpTreat) with Gluma Desensitizer, PRG Barrier Coat (PBC) or Icon infiltrant (n = 11/group) and after exposure to citric acid (LpEro) (6%, pH 2.1, 1 min). The specimens were analyzed under a Laser Scanning Confocal Microscope (n = 2/group) and the products' DC were calculated. Data were subjected to 2-way repeated measures ANOVA and post-hoc Bonferroni (permeability analysis), to paired t-test (for specimens treated with Icon) and to t-test (DC analysis) (α < 0.05). RESULTS: Icon showed the lowest LpTreat and LpEro values, while PBC and Gluma did not differ from each other under these conditions. Icon and PBC showed LpEro similar to a dentin with smear layer. Under the Laser Scanning Confocal Microscope, more deposits were noticeable on dentin after treating with PBC. Gluma presented the deepest penetration in dentin. The DC of PBC was the highest. SIGNIFICANCE: Icon caused the highest reduction on permeability values, followed by PBC and Gluma. PBC generated more deposits covering dentin and seemed to be more efficient after an erosive challenge. The association of a polymeric resin with inorganic ion-releasing fillers seem to be a great strategy to manage dentin hypersensitivity under erosive conditions.

S-PRG-based toothpastes compared to NaF toothpaste and NaF varnish on dentin permeability in vitro.

OBJECTIVES: To analyze the effect of 5 toothpastes containing different percentages of S-PRG fillers compared to NaF toothpaste and NaF varnish on the dentin hydraulic conductance (Lp). METHODOLOGY: Dentin disks (1.0±0.2 mm thickness) were cut from third molars, and their Lp values were evaluated using Flodec. The specimens were allocated into 7 groups (n=8). The minimum (smear layer) and the maximum (after acid etching) Lp values were recorded. Lp was also assessed after treatment with either a 0wt.%, 1wt.%, 5wt.%, 20wt.%, or 30wt.% S-PRG toothpaste, a NaF toothpaste, or a NaF varnish. Toothpastes were applied by brushing for 15 s, allowing it to settle for 1 min, and rinsing with deionized water. The NaF varnish was applied for 4 min and was removed with a probe. Specimens were exposed to citric acid (6%, pH 2.1, 1 min) and their final Lp was recorded. The pH of all products was recorded (n=3) and specimens from each group were analyzed by Laser Scanning Confocal Microscopy (LSCM). Data were subjected to 2-way repeated measures ANOVA and post-hoc Bonferroni (a=0.05). RESULTS: The highest Lp reduction was noticed for the 5wt.% S-PRG toothpaste, NaF toothpaste, and NaF varnish. However, the toothpastes containing 5wt.%, 20wt.%, and 30wt.% of S-PRG were similar to all toothpastes but differed from the NaF varnish. After erosion, all groups retrieved their maximum Lp values, except for the NaF varnish. The LSCM evidenced deposits on the surface of specimens treated with 5%, 20%, and 30% S-PRG-based toothpastes and NaF toothpaste. Even more deposits were observed for the NaF varnish. After the erosive challenge, the deposits were diminished in all groups. CONCLUSION: Toothpastes containing 5wt.%, 20wt.%, and 30wt.% of S-PRG fillers behaved similarly to a conventional NaF toothpaste, even after an erosive challenge. The NaF varnish promoted better reduction of the Lp, but its effect was also diminished after erosion.

MIH-Affected Teeth: Clinical Challenges from Diagnosis to Restorative Management.

Teeth affected by molar incisor hypomineralization (MIH) present micromorphologic changes and hypersensitivity, which increase the risk of developing caries lesions and affect bonding procedures. Considering that practitioners still misdiagnose teeth affected by MIH, there is an urge for more knowledge about this topic in order to propose a more adequate and conservative treatment. The purpose of this study was to report the clinical challenges regarding the restorative management of a patient with MIH. A 13-year-old girl sought dental treatment, complaining about hypersensitivity in posterior teeth. Under clinical exams, notable enamel alterations mainly affecting posterior teeth (including molars) presented particular characteristics frequently attributed to MIH, and visible stains on maxillary central incisors were present. Because the mineral and organic content of MIH-affected enamel differ from sound enamel, it may imply special care for bonding of a restorative material. Thus, in order to promote a minimally invasive approach, selective removal of carious tissue and restoration with microhybrid composite resin was conducted after application of a universal bonding system used as self-etching strategy. After a 2-year follow-up, the restorations presented good clinical performance and the patient had limited hypersensitivity discomfort, suggesting a promising performance.

Correlation between 2D and 3D measurements of cement space in CAD-CAM crowns.

STATEMENT OF PROBLEM: Although the 2D analysis of prosthesis cementation space has been popular, its correlation with volumetric comparison (3D data) of cement space is unclear. PURPOSE: The purpose of this in vitro study was to evaluate the cement space in computer-aided design and computer-aided manufacturing (CAD-CAM) crowns of different materials and correlate 2D measurements of cement space with their corresponding 3D values (volume of cement space) by using microcomputed tomography (µCT) analysis of regions of interest. MATERIAL AND METHODS: Ten molar crowns were milled in lithium disilicate (LD), resin nanoceramic (RN), and zirconia (Z) ceramics. Silicone replicas were produced and used as the analog cement layer and scanned with a desktop X-ray microfocus CT scanner. Twenty-eight slices were evaluated in 3 regions: marginal, axial, and occlusal (n=84 measurement points/specimen). After 3D reconstruction of the cement space, the volume was calculated. Data were statistically evaluated through 2-way ANOVA and Bonferroni test (α=.05). The Pearson correlation test was used to investigate the correlation between the 2D and 3D data. RESULTS: The volumes of the occlusal (LD 10 ±1 mm3; RN 9 ±1 mm3) and axial regions (LD 9 ±2 mm3; RN 8 ±1 mm3) were significantly higher than the volume of the marginal region for LD and RN specimens (LD 6 ±2 mm3; RN 4 ±1 mm3) (both P<.001). For the Z group, the axial region had the highest volume (19 ±2 mm3), followed by the volumes of the occlusal (15 ±1 mm3) and marginal regions (12 ±1 mm3). The Pearson correlation test determined a moderate positive correlation of the marginal area (r=0.606, P<.001) and of the axial region (r=0.588, P<.001). However, a moderate negative correlation was found between volume and thickness of the occlusal area (r=-0.437, P=.016). CONCLUSIONS: Z showed more volume of cement space, as well as thicker cement space than LD and RN. The µCT analysis is an efficient method of analyzing cement thickness and volume in ceramic crowns at the selected regions of interest. A moderate positive correlation was found between the 2D and 3D analyses for the axial and marginal regions of ceramic crowns.

Impact of rehabilitation with removable complete or partial dentures on masticatory efficiency and quality of life: A cross-sectional mapping study.

STATEMENT OF PROBLEM: Tooth loss directly affects mastication, cognitive function, and oral health-related quality of life (OHRQoL). Complete dentures (CDs) and removable partial dentures (RPDs) represent a common oral rehabilitation approach. However, studies addressing the impact of removable dentures on replacing missing teeth are lacking. PURPOSE: The purpose of this clinical study was to evaluate whether the OHRQoL, the jaw function limitation (JFL), and the masticatory efficiency of CD and RPD wearers are similar to those of patients with natural teeth and to evaluate whether wearing removable dentures can predict an effect on the OHRQoL, JFL, and masticatory efficiency of their wearers. MATERIAL AND METHODS: The Oral Health Impact Profile (OHIP-14) questionnaire and the JFL scale were used to measure OHRQoL and JFL. Masticatory efficiency was analyzed by using a subjective color-mixing index for the chewing gum bolus and shape index and an objective colorimetric analysis by using a software program ViewGum. Data were analyzed with Kruskal-Wallis and post hoc Dunn tests, followed by multiple linear regression (α=.05). RESULTS: The results from OHIP-14 evidenced that both denture groups presented a low impact on OHRQoL. JFL was higher for all denture wearers. For the subjective color-mixing analysis, the control and RPD groups presented better masticatory efficiency than CD wearers. Colorimetric analysis evidenced better masticatory efficiency for the control group, who differed from the CD and RPD groups. Wearing RPDs was a predictor of impaired JFL and OHRQoL, and the use of CDs was a predictor of impaired JFL and masticatory efficiency. CONCLUSIONS: Despite being rehabilitated, CD and RPD wearers still had impaired OHRQoL, JFL, and masticatory efficiency. Also, the use of these prostheses can predict a negative effect on these 3 variables.

S-PRG-based toothpastes compared to NaF toothpaste and NaF varnish on dentin permeability in vitro

Abstract Objectives To analyze the effect of 5 toothpastes containing different percentages of S-PRG fillers compared to NaF toothpaste and NaF varnish on the dentin hydraulic conductance (Lp). Methodology Dentin disks (1.0±0.2 mm thickness) were cut from third molars, and their Lp values were evaluated using Flodec. The specimens were allocated into 7 groups (n=8). The minimum (smear layer) and the maximum (after acid etching) Lp values were recorded. Lp was also assessed after treatment with either a 0wt.%, 1wt.%, 5wt.%, 20wt.%, or 30wt.% S-PRG toothpaste, a NaF toothpaste, or a NaF varnish. Toothpastes were applied by brushing for 15 s, allowing it to settle for 1 min, and rinsing with deionized water. The NaF varnish was applied for 4 min and was removed with a probe. Specimens were exposed to citric acid (6%, pH 2.1, 1 min) and their final Lp was recorded. The pH of all products was recorded (n=3) and specimens from each group were analyzed by Laser Scanning Confocal Microscopy (LSCM). Data were subjected to 2-way repeated measures ANOVA and post-hoc Bonferroni (a=0.05). Results The highest Lp reduction was noticed for the 5wt.% S-PRG toothpaste, NaF toothpaste, and NaF varnish. However, the toothpastes containing 5wt.%, 20wt.%, and 30wt.% of S-PRG were similar to all toothpastes but differed from the NaF varnish. After erosion, all groups retrieved their maximum Lp values, except for the NaF varnish. The LSCM evidenced deposits on the surface of specimens treated with 5%, 20%, and 30% S-PRG-based toothpastes and NaF toothpaste. Even more deposits were observed for the NaF varnish. After the erosive challenge, the deposits were diminished in all groups. Conclusion Toothpastes containing 5wt.%, 20wt.%, and 30wt.% of S-PRG fillers behaved similarly to a conventional NaF toothpaste, even after an erosive challenge. The NaF varnish promoted better reduction of the Lp, but its effect was also diminished after erosion.

Salivary cytokines levels, maternal periodontitis and infants' weight at birth: A cohort study in pregnant women with obesity.

INTRODUCTION: Obesity and pregnancy may have synergistic effects on maternal periodontal tissues. In contrast, maternal obesity and periodontitis are antagonistic factors for the babies' weight at birth. This study evaluated, during pregnancy (T1) and after delivery (T2), periodontal parameters and salivary levels of cytokines in women with obesity, and the association of these outcomes with the baby's weight at birth. METHODS: After matching by age, socioeconomic status and systemic health, the sample was composed of pregnant women with obesity (GO = 25; BMI ≥30 kg/m2) and normal BMI (GN = 25; BMI between 18.5 and 24.99 kg/m2), who were evaluated regarding: periodontal parameters; salivary levels of TNF-α, IL-1ß and leptin (Luminex® assay); and babies' weight at birth. Mann-Whitney, Friedman, ANOVA; chi-square and Cochran's Q tests were applied (p < 0.05). RESULTS: GO showed higher prevalence of periodontitis in T1 and T2 (p <0.001), with higher salivary levels of TNF-α (p = 0.003) and IL-1ß (p = 0.009) in T1. IL-1ß significantly decreased after delivery in GO. No intergroup differences for leptin levels were found, but both groups had a significant reduction of leptin levels between periods (p <0.001). GO had children with lower birth weight (p = 0.022), being classified as low (<2,500 g) or insufficient (2,500-2,999 g) weight. DISCUSSION: It is suggestive that the inflammatory pattern caused by obesity and periodontitis, mainly related to high levels of TNF-α, impair the babies' weight at birth, resulting in more frequency of low/insufficient weight at birth.

Obliterating potential of active products for dentin hypersensitivity treatment under an erosive challenge.

OBJECTIVES: To compare the effect of 5 desensitizing agents on the hydraulic conductance (Lp) of dentin and to analyze its surface under a Laser Scanning Confocal Microscope (LSCM) before and after an erosive challenge. METHODS: Lp was analyzed in the following sequence: in the presence of smear layer (pMin), after a 15-second acid etching (pMax), after treatment with a desensitizing agent (pTreat) and after a 1-minute erosive challenge (6% citric acid - pEro). Fifty 1.0 ± 0.2 mm-thick dentin disks were prepared from sound human third molars and were randomly distributed into 5 groups (n = 10): FG-Fluoride gel (control), SA-Sensiactive, PR-Sensitive Pro-Relief, NP-Desensibilize Nano-P and EV-Enamel Pro Varnish. Data were analyzed by two-way ANOVA and Tukey tests (α<0.05). Additional specimens were analyzed under a Laser Scanning Confocal Microscope (LSCM) and by Energy Dispersive X-ray Spectroscopy (EDS). RESULTS: All materials reduced the Lp in some extent, except for FG and EV. After the erosive challenge, SA was the only material effectively able to keep the same Lp of the post-treatment phase, while the other products showed lower resistance upon an erosive challenge. Under the LSCM, the SA and NP materials were more effective to obliterate the opened dentin tubules and demonstrated higher resistance upon an erosive challenge. The EDS analysis evidenced levels of Ca, O, P, Si, Na and S. CONCLUSIONS: Product containing potassium oxalate was the most effective in reducing Lp of dentin samples before and after an erosive challenge. Under a LSCM, products containing potassium oxalate or hydroxyapatite crystals seemed to be occluding the dentin tubules after an erosive challenge.

COVID-19 and its relation to pregnancy and neonates: a systematic review / COVID-19 e sua relação com a gravidez e neonatos: uma revisão sistemática

Abstract Objectives: this study systematically reviewed the literature in order to better understand the association among COVID-19, pregnancy and neonates. Methods: MEDLINE, EMBASE, Web of Science, BVS and SCOPUS were assessed, considering the terms: (covid 19 OR covid-19 OR novel coronavirus OR 2019 novel coronavirus OR 2019-nCoV OR sarscov 2 OR sars-cov-2 OR sarscov2 OR sars cov-2) AND (pregnancy OR pregnant OR pregnant women OR gestation OR gestational) AND (infant OR fetal OR neonatal). Thirty full-text were included (408 pregnant women, 11 non-pregnant women and 279 neonates). Results: fever (45.83%) and cough (31.61%) were the main symptoms of COVID-19 during the pregnancy. Low levels of lymphocytes (32.10%), elevated levels of C-reactive protein (32.35%); leukocytosis (29.41%); neutrophil (5.88%); and radiographic alterations on chest CT, x-ray or ultrasound (45.84%) were the main laboratorial findings. Cesarean delivery and preterm were registered in 239 and 49 cases, respectively. Ten neonates tested positive for SARS-CoV-2. Conclusion: when COVID-19 pneumonia affects women during pregnancy, the symptoms are similar to those experienced by non-pregnant women. In addition, there is still no plausible evidence suggesting vertical transmission of SARS-CoV-2 virus from mother to child.

Resumo Objetivos: este estudo revisou sistematicamente a literatura para melhor compreender a associação entre COVID-19, gravidez e neonatos. Métodos: MEDLINE, EMBASE, Web of Science, BVS e SCOPUS foram acessadas, considerando os termos: (covid 19 OR covid-19 OR novel coronavirus OR 2019 novel coronavirus OR 2019-nCoV OR sarscov 2 OR sars-cov-2 OR sarscov2 OR sars cov-2) AND (pregnancy OR pregnant OR pregnant women OR gestation OR gestational) AND (infant OR fetal OR neonatal). Trinta textos completos foram incluídos (408 gestantes, 11 mulheres nãogestantes e 279 recém-nascidos). Resultados: febre (45,83%) e tosse (31,61%) foram os principais sintomas da COVID-19 durante a gestação. Baixos níveis de linfócitos (32,10%), elevados níveis de proteínas Creativa (32,35%); leucocitose (29,41%); neutrófilo (5,88%); e alterações radiográficas sob tomografia computadorizada de tórax, radiografia ou ultrasom (45,84%) foram os principais achados laboratoriais. Parto por cesárea e prematuridade foram registrados em 239 e 49 casos, respectivamente. Dez recém-nascidos testaram positivo para o virus SARS-CoV-2. Conclusão: quando a pneumonia COVID-19 afeta mulheres durante a gravidez, os sintomas são semelhantes aos experimentados por mulheres não grávidas. Além disso, ainda não há evidências plausíveis que sugiram a transmissão vertical do vírus SARS-CoV-2 de mãe para filho.

Effect of TiF4 varnish after pre-treatment with proanthocyanidin or chlorhexidine on the progression of erosive dentin loss in the presence or absence of the demineralized organic matrix.

This study evaluated the protective effect of TiF4 varnish, after pre-treatment with proantocyanidin or chlorhexidine, on the progression of erosive dentin loss (EDL), under the presence or absence of the demineralized organic matrix (DOM). Bovine root dentin samples were eroded for 30 min (0.1% citric acid, pH 2.5) and the loss was measured by profilometry. Half of them were subjected to the DOM removal using collagenase for 4 days, while the other half remained immersed in water. The removal of DOM was checked by profilometry. Samples were divided into 24 groups (n = 15) according to the factors: 1- With or without DOM; 2- Pre-treatment with 0.012% chlorhexidine gel, 10% proanthocyanidin gel or untreated for 1 min; 3-Final Treatment with TiF4 varnish, NaF varnish, placebo varnish or untreated for 6 h. The samples were submitted to a pH cycling for 5 days: 0.1% citric acid (4 × 90s/day) and artificial saliva between the challenges. The final profile was obtained for the calculation of EDL (µm, three-way ANOVA/Tukey test). When DOM was preserved, the EDL was lower compared to the condition without DOM (7.08 ± 4.03 µm and 9.80 ± 3.79 µm, p < 0.001, respectively), regardless of the treatments. The pre-treatment had no influence on the progression of EDL (p = 0.637), while the final treatment (TiF4 varnish only, 6.77 ± 4.08 µm) was effective in reducing the progression of EDL (NaF varnish: 9.52 ± 4.02 µm; Placebo varnish: 8.64 ± 4.06 µm and no treatment: 8.80 ± 3.95 µm). It can be concluded that DOM has important protective effect on the progression of EDL. TiF4 was the unique treatment capable of reducing EDL progression, regardless of the pre-treatment of DOM.

Experimental self-etching resin infiltrants on the treatment of simulated carious white spot lesions.

OBJECTIVES: To evaluate the penetration depth (µm) of experimental resin infiltrants containing different percentages of triethylene glycol dimethacrylate (TEGDMA) and phosphoric acid 2-hydroxyethyl methacrylate ester (PAM) in artificial carious white spot lesions (WSL). METHODS: WSL were produced in 65 bovine flat enamel specimens by pH cycling protocol, which were treated with either Icon (control) or experimental acidic infiltrants based on different percentages of TEGDMA and PAM monomers (acidic), and their association or not with previous acid-etching with phosphoric acid. Ten readings using Confocal Laser Scanning Microscopy were conducted on each specimen and the penetration depth was calculated from the surface until the deepest point with the fluorescent dye Rhodamine B (0.02 mg/mL). The pH and the viscosity of the experimental infiltrants were also tested. Data were statistically analyzed with two-way ANOVA and Tukey tests (α < 0.05). RESULTS: The material factor and the interaction material*acid-etching were statistically significant. The lowest penetration depth was observed for the samples treated with the commercial infiltrant after etching with 15% hydrochloric acid. When specimens were pre-treated with PA, highest penetration was seen for specimens treated with 100% TEGDMA, which differed from all other groups. The lowest penetration was seen for those treated with 50:50 TEGDMA:PAM infiltrants. When specimens were not previously etched, highest penetration was seen for Icon, which differed only from those treated with 25% TEGDMA 75% PAM, where the lowest values were seen. The values of viscosity increased and the pH decreased with the addition of PAM in the infiltrant formulations. CONCLUSION: the association between TEGDMA and PAM seems to allow similar infiltration depth reached by Icon infiltrant without acid etching the enamel surface.

Nonmetal clasp dentures: What is the evidence about their use?

The aim was to discuss the indications, contraindications, advantages, and disadvantages of Nonmetal clasp dentures (NMCDs), as well as the most relevant properties of its constituent materials. A search was conducted using the keywords: "nonmetal clasp dentures," "thermoplastic resin," "flexible resin removable partial denture," "polyamide," and "nylon" in databases PubMed/Medline, Lilacs, SciELO, and textbooks between 1955 and 2020. Theses and texts without reliable sources of publication were excluded. Once the analysis instruments were determined, the data were analyzed and discussed. NMCDs present high flexibility, easy adaptation to the abutments, color compatibility and biocompatibility with the oral mucosa, and absence of visible metal clasps. However, they need laboratory relining, grinding, and polishing, do not have criteria for its planning, become rougher and stained over time, and are able to traumatize supporting tissues. The association with metal components seems to be an alternative to increase the success of NMCDs by combining esthetics and biomechanical principles of conventional removable partial dentures. The lack of long-term clinical studies makes the professionals to rely solely on previous experiences or on the manufacturers' recommendations. It suggested that NMCDs must be indicated with caution when not used temporarily.

Structural, chemical and optical characterizations of an experimental SiO2-Y-TZP ceramic produced by the uniaxial/isostatic pressing technique.

This study aimed to produce a new SiO2+Y-TZP ceramic via uniaxial/isostatic compression that was structurally and chemically characterized relating to its translucency and flexural strength. SiO2 and Y-TZP were mixed using a ball mill, pressed and sintered at 1150 °C. The optical and mechanical properties of the specimens were compared to lithium disilicate (LD) and zirconia-reinforced lithium silicate (ZLS) (Kruskal-Wallis, α = 0.05). The Fourier Transform Infrared Spectroscopy bands suggested an interaction between Si, O and Zr. Contrast ratio and translucency parameter of the experimental ceramic were higher and lower, (p = 0.000001) respectively, than those of the LD and ZLS. The experimental ceramic presented similar flexural strength to ZLS, but lower than LD (p < 0.0001). It can be concluded that this processing method is efficient to obtain a SiO2+Y-TZP ceramic and 1150 °C crystallizes SiO2 without inducing t-m transformation. The SiO2+Y-TZP ceramic presented lower translucency and higher masking ability than the commercially available glass-ceramics, but similar flexural strength to one glass-ceramics.