Marginal sealing of relocated cervical margins of mesio-occluso-distal overlays.

We investigated the effect of cervical marginal relocation (CMR) on marginal sealing with two different viscosity resin composites, before adhesive cementation of composite computer-aided design/computer-assisted manufacture mesio-occluso-distal (MOD) overlays. Standardized MOD cavities prepared in 39 human molars were randomly assigned to three groups. The proximal margins on the mesial side were located 1 mm below the cementoenamel junction. On the distal side of the tooth, the margins were located 1 mm above the cementoenamel junction. In Groups 1 and 2, mesial proximal boxes were elevated with a hybrid composite (GC Essentia MD) and a flowable composite (GC G-ænial Universal Flo), respectively. CMR was not performed in Group 3. The overlays were adhesively cemented, and interfacial leakage was quantified by scoring the depth of silver nitrate penetration along the adhesive interfaces. Leakage score at the dentin-CMR composite interface did not significantly differ between the two tested composites but was significantly lower for Group 3. In all groups, scores were significantly higher at the dentin interface than at the enamel interface. These results indicate that the performance of flowable and microhybrid resin composites, as indicated by marginal sealing ability, is comparable for CMR

Adherence to Mediterranean diet, physical activity level, and severity of periodontitis: Results from a university-based cross-sectional study

Background: The aim of this study was to evaluate the association between adherence to Mediterranean diet (MD) and physical activity (PA) level with the periodontal status of a University-based cohort of individuals. Methods: A total of 235 individuals were included in the study. MD adherence and PA level were registered through validated questionnaires, together with a full periodontal examination. Crude and adjusted odds ratios (ORs) [95% confidence interval] were calculated to evaluate the association between MD adherence, PA level, and periodontitis severity. A final logistic multivariate regression model was built to evaluate the impact of the combination between low MD adherence and low PA level on the prevalence of Stage III/IV periodontitis. Results: The adjusted ORs for Stage III/IV periodontitis were 1.65 [0.84 to 3.28; P = 0.42] for low PA and 5.63 [3.21 to 9.84; P = 0.00] for low MD adherence. The final logistic multivariate regression model resulted in OR = 10.23 [4.01, 26.09; P = 0.00] of having Stage III/IV periodontitis in individuals with low MD adherence and low PA. Conclusions: Individuals conducting a lifestyle characterized by the combination of low MD adherence and lack of regular exercise had 10 times the odds to have severe forms of periodontitis. © 2022 The Author

Different Post Placement Strategies for the Restoration of Endodontically Treated Maxillary Premolars with Two Roots: Single Post vs Double Post

Aim and objective: The present study compared the fracture strength and failure pattern of endodontically treated, bi-rooted, maxillary premolars with different number of coronal walls and postendodontic restoration (one vs double post). Materials and methods: 105 premolars were divided into 3 groups according to the number of residual walls: control group (intact teeth; n= 15), group 1 (3 residual walls; n = 45), group 2 (2 residual walls; n = 45). Each test group was then divided into 3 subgroups (n = 15 each) according to postendodontic restoration: no post (A), 1 post (B) or 2 posts (C). A load was applied parallel to the longitudinal axis of the teeth, thus simulating physiological occlusion. ANOVA and Tukey’s tests were used to detect fracture strength differences among groups, while Chisquare test was used to check differences in fracture pattern. Results: No significant differences were observed between control group (intact teeth) and groups A1 (p = 0.999), B1 (p = 0.997) and C1 (p = 1.000); statistically significant differences were detected between control group and groups A2 (p < 0.001), B2 (p < 0.001) and C2 (p < 0.05). Different post placement techniques were non-significantly associated with fracture pattern in both groups 1 (p = 0.666) and 2 (p = 0.143) while, irrespective of the number of posts, the presence of the post was significantly associated with the fracture pattern in teeth with two residual walls. The double-post technique did not further improve the fracture resistance of hardly damaged endodontically treated maxillary bi-rooted premolars compared to single-post technique. Therefore, the insertion of a single post in the palatal canal could be a safer and more conservative choice. Clinical significance: The double-post technique did not further improve the fracture resistance of severely structurally compromised endodontically treated maxillary premolars with two roots compared to the single-post technique. Therefore, the safer and less invasive treatment is the placement of a single post in the palatal canal

EFFECTS OF THE ADDITION OF SUGARS ON THE THERMOSTABILITY OF BETANIN FROM Beta vulgaris L.

O impacto da adição de açúcares na estabilidade das betaninas de Beta vulgaris L. (beterraba) durante o tratamento térmico entre 50 e 80°C e pH 5 foi investigado. A degradação das betaninas pura e adicionada de 10% de sacarose e 40% de frutose seguiu modelo de cinética de primeira ordem e conforme aumento da temperatura, houve aumento dos valores da constante de degradação térmica (Kd), redução na meia-vida e nos valores do tempo de redução decimal (D). Termodinamicamente, apresentando valores de variação de entalpia (ΔH) mais altos (entre 99,66 e 99,41 kJ mol-1) que o extrato com a adição de sacarose (entre 85,27 e 85,03 kJ mol-1) e controle (entre 78,85 e 78,61 kJ mol-1), a incorporação de frutose foi mais promissora no aumento da estabilidade do extrato de betaninas. Os valores positivos para a variação da energia livre de Gibbs (ΔG) indicaram que a reação de degradação das betaninas foi não-espontânea e os baixos valores da variação de entropia (ΔS) para o extrato com frutose (entre 0,02 e 0,03 J mol-1K-1) indicaram que o estado do material estava próximo ao seu equilíbrio termodinâmic

Comparison of the surface tension of 5.25% sodium hypochlorite solution with three new sodium hypochlorite-based endodontic irrigants

Aim To investigate the surface tension characteristics of 5.25% sodium hypochlorite and three recently introduced sodium hypochlorite solutions, which had been modified to reduce their surface tension: ChlorXtra, Hypoclean A and Hypoclean B. Methodology Freshly produced MilliQ water was used as a reference liquid. All measurements of surface tension were taken by the Wilhelmy plate technique, using a Cahn DCA-322 Dynamic Contact Angle Analyzer at the temperature of 22°C. A glow-discharge cleaned glass slide was immersed in 5 mL of the test liquid in a beaker cleaned with hot chromic acid, rinsed with MilliQ water and finally air plasma-cleaned in a glow-discharge reactor. The force on the glass slide was recorded continuously by the instrument software as the beaker was raised and withdrawn at the constant speed of 40 micron/s, until at least 1 cm of the glass slide was immersed. The typical accuracy was 0.5 mJ m ) had the highest surface tension values (P < 0.01) compared to ChlorXtra (33.14 mJ m ). Hypoclean A had the lowest surface tension (P < 0.01). Conclusions The new 5.25% sodium hypochlorite solutions modified with surfactants, Hypoclean A and Hypoclean B, had surface tension values that were significantly lower (P < 0.01) than Chlor-Xtra and 5.25% NaOCl. Because of their low surface tension and increased contact with dentinal walls, these new irrigants have the potential to penetrate more readily into uninstrumented areas of root canal system as well as allow a more rapid exchange with fresh solution, enabling greater antimicrobial effectiveness and enhanced pulp tissue dissolution ability

In vivo and in vitro permeability of one-step self-etch adhesives

Adhesive dentistry should effectively restore the peripheral seal of dentin after enamel removal. We hypothesize that non-rinsing, simplified, one-step self-etch adhesives are effective for minimizing dentin permeability after tooth preparation procedures. Crown preparations in vital human teeth were sealed with Adper Prompt, Xeno III, iBond, or One-Up Bond F. Epoxy resin replicas were produced from polyvinyl siloxane impressions for SEM examination. Dentin surfaces from extracted human teeth were bonded with these adhesives and connected to a fluid-transport model for permeability measurements and TEM examination. Dentinal fluid droplets were observed from adhesive surfaces in resin replicas of in vivo specimens. In vitro fluid conductance of dentin bonded with one-step self-etch adhesives was either similar to or greater than that of smear-layer-covered dentin. TEM revealed water trees within the adhesives that facilitate water movement across the polymerized, highly permeable adhesives. Both in vitro and in vivo results did not support the proposed hypothesis.published_or_final_versio

Influence of different scanning techniques on in vitro performance of CAD-CAM-fabricated fiber posts

This study assessed push-out strength, cement layer thickness, and interfacial nanoleakage of luted fiber posts fabricated with computer-aided design/computer-assisted manufacture (CAD/CAM) technology after use of 1 of 3 scanning techniques, namely, direct scanning of the post space (DS), scanning of a polyether impression of the post space (IS), and scanning of a plaster model of the post space (MS). Thirty premolars were randomly assigned to three groups corresponding to the scanning technique. Posts were computer-designed and milled from experimental fiber-reinforced composite blocks. The mean (±SD) values for push-out strength and cement thickness were 17.1 ± 7.7 MPa and 162 ± 24 μm, respectively, for DS, 10.7 ± 4.6 MPa and 187 ± 50 μm for IS, and 12.0 ± 7.2 MPa and 258 ± 78 μm for MS specimens. Median (interquartile range) interfacial nanoleakage scores were 3 (2-4) for DS, 2.5 (2-4) for IS, and 3 (2-4) for MS. Post retention was better for fiber posts fabricated by DS technique than for those fabricated by IS and MS. Cement thickness did not differ between DS and IS specimens, but the cement layer was significantly thicker in the MS group than in the other two groups. Scanning technique did not affect sealing ability, as the three groups had comparable nanoleakage values

Post-Retained Single Crowns versus Fixed Dental Prostheses: A 7-Year Prospective Clinical Study

Biomechanical integrity of endodontically treated teeth (ETT) is often compromised. Degree of hard tissue loss and type of final prosthetic restoration should be carefully considered when making a treatment plan. The objective of this prospective clinical trial was to assess the influence of the type of prosthetic restoration as well as the degree of hard tissue loss on 7-y clinical performance of ETT restored with fiber posts. Two groups (n = 60) were defined depending on the type of prosthetic restoration needed: 1) single unit porcelain-fused-to-metal (PFM) crowns (SCs) and 2) 3- to 4-unit PFM fixed dental prostheses (FDPs), with 1 healthy and 1 endodontically treated and fiber post-restored abutment. Within each group, samples were divided into 2 subgroups (n = 30) according to the amount of residual coronal tissues after abutment buildup and final preparation: A) >50% of coronal residual structure or B) equal to or <50% of coronal residual structure. The clinical outcome was assessed based on clinical and intraoral radiographic examinations at the recalls after 6, 12, 24, 36, 48, and 84 mo. Data were analyzed by Kaplan-Meier log-rank test and Cox regression analysis (P < 0.05). The overall 7-y survival rate of ETT restored with fiber post and either SCs or FDPs was 69.2%. The highest 84-mo survival rate was recorded in group 1A (90%), whereas teeth in group 2B exhibited the lowest performance (56.7% survival rate). The log-rank test detected statistically significant differences in survival rates among the groups (P = 0.048). Cox regression analysis revealed that the amount of residual coronal structure (P = 0.041; hazard ratio [HR], 2.026; 95% confidence interval [CI] for HR, 1.031–3.982) and the interaction between the type of prosthetic restoration and the amount of residual coronal structure (P = 0.024; HR, 1.372; 95% CI for HR, 1.042–1.806) were statistically significant factors for survival (ClinicalTrials.gov NCT01532947)