Biomechanical consideration in tooth-supported glass-ceramic restorations: A systematic review and meta-analysis of survival rates and irreparable failures.

STATEMENT OF PROBLEM: Knowledge on the biomechanical behavior of glass-ceramics, their survival rate over time, and their potential failures is essential for decision-making in clinical practice. Systematic reviews and meta-analysis of their survival rates and irreparable failures are lacking. PURPOSE: The purpose of this systematic review and meta-analysis was to evaluate the survival rates and irreparable failures of various monolithic glass-ceramic dental restorations to help determine biomechanical indications. MATERIAL AND METHODS: A comprehensive literature search was conducted across the PubMed, Scopus, Web of Science, and EMBASE databases based on the population, intervention, comparison, and outcome (PICO) question, risk of bias assessment, data extraction, subgroup analysis, and meta-analysis. Both randomized and nonrandomized clinical trials that reported survival rate and irreparable failure were screened. The risk, with a 95% confidence interval, was calculated by using the Mantel-Haenszel method. RESULTS: A total of 46 articles met the inclusion criteria: 8 for laminate veneers, 20 for partial coverage restorations, 11 for single crowns, and 6 for fixed partial dentures, encompassing 1715 participants rehabilitated with 4209 restorations. The estimated cumulative survival rate for partial coverage restorations was 90% over an average span of 6.2 years, with an irreparable failure occurrence of n=5.9. Laminate veneers had a survival rate of 90.2% over 6.5 years, with an irreparable failure occurrence of n=8.2. Single crowns had a survival rate of 96% over 4.6 years and an irreparable failure of n=2.7. Conversely, fixed partial dentures had a survival rate of 76.1% over 6.5 years with an irreparable failure of n=5.2. CONCLUSIONS: Glass-ceramic materials demonstrate relatively high survival rates, indicating that they provide a safe and reliable option for partial coverage restorations, laminate veneers, and single crowns. However, fixed partial dentures had a higher proportion of irreparable failures and a lower survival rate, and caution is required.

Recent advances in dental zirconia: 15 years of material and processing evolution.

OBJECTIVES: The objective was to discuss the research on zirconia published in the past 15 years to help the dental materials community understand the key properties of the types of zirconia and their clinical applications. METHODS: A literature search was performed in May/2023 using Web of Science Core Collection with the term "dental zirconia". The search returned 5102 articles, which were categorized into 31 groups according to the research topic. RESULTS: The current approach to improving the translucency of zirconia is to decrease the alumina content while increasing the yttria content. The resulting materials (4Y-, 5Y-, and above 5 mol% PSZs) may contain more than 50% of cubic phase, with a decrease in mechanical properties. The market trend for zirconia is the production of CAD/CAM disks containing more fracture resistant 3Y-TZP at the bottom layers and more translucent 5Y-PSZ at the top. Although flaws located between layers in multilayered blocks might represent a problem, newer generations of zirconia layered blocks appear to have solved this problem with novel powder compaction technology. Significant advancements in zirconia processing technologies have been made, but there is still plenty of room for improvement, especially in the fields of high-speed sintering and additive manufacturing. SIGNIFICANCE: The wide range of zirconia materials currently available in the market may cause confusion in materials selection. It is therefore imperative for dental clinicians and laboratory technicians to get the needed knowledge on zirconia material science, to follow manufacturers' instructions, and to optimize the design of the prosthetic restoration with a good understanding where to reinforce the structure with a tough and strong zirconia.

Harmonizing color measurements in dentistry using translucent tooth-colored materials.

BACKGROUND: Since color measurements are relative, the discrepancy among different instruments is alarmingly high. This multicenter study evaluated the effectiveness of instrument calibration and inter-instrument harmonization of different spectrophotometers with the same optical geometry using tooth-colored, translucent dental materials. METHODS: The coordinating center (CC) spectrophotometer was calibrated using the NPL Ceram Series II set. Two sets of 10 specimens, labeled 1 to 10 and I to X (10 mm in diameter and 1 mm thick), were tested at CC and three research sites (RS1, RS2, and RS3) using the same d/8° optical geometry spectrophotometers. Calibration factors were calculated for each material and site to obtain the average calibration factors for sets 1-10, set I-X, and the combination of both. The differences among the non-corrected and corrected reflection values were calculated using CIEDE2000 (DeltaE00) and CIELAB (DeltaEab) color difference formulas and were submitted to ANOVA and Tukey test (α = 0.05). RESULTS: A significant decrease of color differences between non-corrected as compared to corrected measurements was recorded for all CC-RS and RS-RS comparisons. The reduction of DeltaE00 values between non-corrected and corrected for CC-RS1, CC-RS2, and CC-RS3 were 83.1%, 77.2%, and 73.6%, respectively. The corresponding DeltaE00 values for RS1-RS2, RS1-RS3, and RS2-RS3 comparisons, indirectly compared in the experiment, were 84.2%, 82.8%, and 68.5%, respectively. There was a significant reduction of DeltaE00 and DeltaEab color difference for all combined RS pairs and each of three RS pairs, corrected with one of two specimen sets calibration factors separately. CONCLUSIONS: Calibration and harmonization of color measurements in dentistry using tooth-colored, translucent restorative materials significantly decreased measurement discrepancies between the coordinating center and research sites and among pairs of research sites.

Comparison of subcritical growth parameters of a Y-TZP obtained via cyclic or dynamic fatigue tests.

OBJECTIVE: The objective of this study was to 1) compare the stress corrosion coefficient (n) of a Y-TZP obtained by two fatigue tests: cyclic and dynamic and 2) evaluate the effect of frequency in the characteristic lifetime and the existence of interaction between the cyclic fatigue and slow crack growth. METHODS: A total of 145 Y-TZP specimens were produced in accordance with the manufacturer's instructions. These specimens, measuring 4.0 × 3.0 × 25.0 mm, were used for dynamic (n = 70) and cyclic fatigue tests (n = 75). The specimens were obtained from CAD/CAM blocks, sectioned, and sintered in a furnace at 1530 °C with a heating rate of 25 °C/min. They were tested in their "as-sintered" form without any additional surface treatment. The fatigue tests were conducted using a four-point bending to obtain the slow crack growth parameters (n). The cyclic fatigue test was also conducted in two frequencies (2 and 10 Hz), using stress levels between 350 and 600 MPa. Data from these tests were analyzed using ASTM C 1368-00 formulas and Weibull statistics. Scanning electron microscope (SEM) was used for fracture surface analysis to identify the origin of the fracture. Critical defect size was measured and used, along with flexural strength values, to estimate fracture toughness. Dynamic fatigue test data were used to obtain subcritical crack growth (SCG) parameters and perform Weibull statistical analysis. The cyclic fatigue data were used in the General Log-linear Model equation using the ALTA PRO software. Data were analyzed using one-way ANOVA followed by Tukey post-hoc tests and Student's t-test at a significance level of p ≤ 0.05. RESULTS: In the dynamic fatigue test, the values obtained for σfo and n were 667 and 54, respectively. This parameter indicates how the strength of the material diminishes over time due to internal cracks. The Weibull parameters obtained from the same test results were m = 7.9, σ0 = 968, 9 and σ5% = 767, which indicates the reliability of the material. The Weibull parameters obtained by cyclic fatigue were statistically similar for the two frequencies used, the m* was 0.17 (2 Hz) and 0.21 (10 Hz); characteristic lifetimes (η) were 1.93 × 106 and 40,768, respectively. The n values obtained by cyclic fatigue were 48 and 40 at frequencies of 2 and 10 Hz, respectively. There was no effect of the frequency, the stress level or the interaction of the two in the Y-TZP lifetime, when analysed by General Log Linear Model. SIGNIFICANCE: the n values obtained by cyclic and dynamic fatigue tests showed no statistically significant difference and the effect of frequency in the characteristic lifetime and the existence of interaction between the cyclic fatigue and subcritical growth were not observed in the tested specimens.

Development of Y-TZP/MWCNT-SiO2 nanocomposite for dental protheses.

Y-TZP/MWCNT-SiO2 nanocomposite was synthesized by co-precipitation and hydrothermal treatment methods. After the characterization of the MWCNT-SiO2 powder, specimens were obtained from the synthesized material Y-TZP/MWCNT-SiO2 by uniaxial pressing for a second characterization and later comparison of its optical and mechanical properties with the conventional Y-TZP. The MWCNT-SiO2 was presented in bundles of carbon nanotubes coated by silica (mean length: 5.10 ± 1.34 µm /D90: 6.9 µm). The composite manufactured was opaque (contrast ratio: 0.9929 ± 0.0012) and had a white color with a slightly difference from the conventional Y-TZP (ΔE00: 4.4 ± 2.2) color. The mechanical properties of Y-TZP/MWCNT-SiO2: vickers hardness (10.14 ± 1.27 GPa; p = 0.25) and fracture toughness (4.98 ± 0.30 MPa m1/2; p = 0.39), showed no significant difference from the conventional Y-TZP (hardness: 8.87 ± 0.89; fracture toughness: 4.98 ± 0.30 MPa m1/2). However, for flexural strength (p = 0.003), a lower value was obtained for Y-TZP/MWCNT-SiO2 (299.4 ± 30.5 MPa) when compared to the control Y-TZP (623.7 ± 108.8 MPa). The manufactured Y-TZP/MWCNT-SiO2 composite presented satisfactory optical properties, however the co-precipitation and hydrothermal treatment methods need to be optimized to avoid the formation of porosities and strong agglomerates, both from Y-TZP particles and MWCNT-SiO2 bundles, which lead to a significant decrease in the material flexural strength.

Special care in dental curriculum: A transversal axis for integrating oral health with systemic health.

AIMS: Distance between dentistry and medicine is a traditional and historical obstacle that affects multiple levels of the health system, especially the health policies to improve health service quality. Changes in dental education, especially involving the adoption of integrative health models in professional development, are considered essential for reducing this gap. We aimed to show a dental curriculum focused on special care as a tool for medicine-dentistry integration. METHODS: In this study, we present a new proposal for an undergraduate dental curriculum in which topics related to special care are addressed transversally and are the core for interdisciplinary integration of oral health with systemic health. We also describe how themes related to dental home care and hospital dentistry were included in this course as basic professional competencies. RESULTS AND CONCLUSION: This initiative is aligned with the global trend to adopt educational systems that contribute to the reduction of health care inequalities and improve health service quality.

Effect of intracanal diode laser irradiation on fracture resistance of roots restored with CAD/CAM posts

Aim: To evaluate the fracture resistance of roots restored with CAD/CAM-fabricated posts, receiving or not intracanal laser treatment, compared with glass fiber posts under mechanical cycling. Methods: Twenty-seven endodontically treated, single-rooted teeth were divided into 3 groups: group 1 (control), prefabricated glass fiber posts relined with resin composite; group 2, CAD/CAM-fabricated intraradicular posts using Resin Nano Ceramic (RNC) blocks; and group 3, CAD/CAM-fabricated intraradicular posts using RNC blocks in canals irradiated with a 940-nm diode laser (100 mJ, 300-um optic fiber, coronal-apical and apical-coronal helical movements, speed of 2 mm/second, 4 times each canal). After cementation of the coping, cyclic loading was applied at an angle of 135° to the long axis of the root, with a pulse load of 130 N, frequency of 2.2 Hz, and 150,000 pulses on the crown at a point located 2 mm below the incisal edge on the lingual aspect of the specimen. Every 50,000 cycles, the specimens were evaluated for root fracture occurring below or above the simulated bone crest. Results were analyzed by one-way ANOVA followed by Tukey's test (p<0.05). Results: Group 1 was the least resistant, while groups 2 and 3 were the most resistant. Group 1 differed significantly from groups 2 and 3 (p<0.01), but there was no difference between groups 2 and 3 (p<0.01). Conclusion: Treatment of the intracanal surface with diode laser had no influence on fracture resistance of roots restored with CAD/CAM-fabricated posts, but a longer cycling time is required to evaluate the real benefits of diode laser irradiation

Advances in Ceramics for Dental Applications.

The purpose of this study is to present current dental ceramic materials and processing methods. The clinical indication was emphasized on basis of the material's microstructure and composition. Studies of ceramic characterization were also discussed, as they impact the clinical indication and serve as a parameter for the development of new materials. The novel strategies were mostly found aiming to mimic the natural dental structures, provide mechanical reliability, and develop predictable restorations in terms of adaptation and design.

Do tooth-supported zirconia restorations present more technical failures related to fracture or loss of retention? Systematic review and meta-analysis.

OBJECTIVES: This systematic review was performed to determine the main cause of technical failure of tooth-supported zirconia crowns and fixed partial dentures (FPDs), categorizing them as fracture/chipping or loss of retention/decementation. MATERIALS AND METHODS: Electronic and manual searches were performed for randomized clinical trials, prospective clinical trials, and prospective cohort studies that reported the technical failure rates of zirconia restorations. The Cochrane Collaboration risk-of-bias tool and Newcastle-Ottawa scale were used to assess the quality of the studies. RESULTS: Fifty-two studies were included and most of them had unclear risk of bias. Considering all reported fractures/chipping, for veneered crowns with 1 to 3 years of follow-up, the relative risk (RR) of fracture in relation to loss or retention was 3.95 (95% CI 1.18-13.23; p = 0.03). For 4 to 6 years of follow-up, the RR was 5.44 (95% CI 1.41-20.92; p = 0.01). For veneered FPDs with 1 to 3 years of follow-up, the RR was 5.98 (95% CI 2.31-15.01; p = 0.0002). For 4 to 6 years of follow-up, the RR was 3.70 (95% CI 1.63-8.41; p = 0.002). For 7 years or more of follow-up, the RR was 3.45 (95% CI 1.84-6.46; p = 0.0001). When only framework fractures were considered, there were no significant differences for the RR in all follow-up periods (p > 0.05). CONCLUSIONS: Higher RR for fracture/chipping in relation to decementation for veneered zirconia crowns and FPDs at all follow-up times. For framework fractures, no difference was observed between the risk of failure of the restoration due to fracture or decementation. CLINICAL RELEVANCE: Zirconia crowns and FPDs showed relatively high success and survival rates. However, considering the technical failures, there is approximately four times higher chance of fracture/chipping than loss of retention for both single and multi-unit tooth-supported veneered zirconia restorations.

Effects of polyvinyl chloride film and oxygen-blocking gel on irradiance and depth of cure.

This study aimed to analyze the effects of polyvinyl chloride (PVC) film and oxygen-blocking gel (OBG) on the irradiance from an LED source and the depth of cure of a composite resin. Irradiance was measured with a curing radiometer, and curing depth was evaluated according to the methods described by the International Organization for Standardization (ISO 4049). Twelve experimental conditions were investigated in a 3 × 4 factorial design (n = 5 specimens per condition): no PVC film at the tip of the device, fitted PVC film, or misfit PVC film; and no OBG or a 1-, 2-, or 3-mm-thick layer of OBG. The data were analyzed using analysis of variance and Tukey tests (P < 0.05), and a linear regression test was performed between the variables (P < 0.05). The analyses showed that the variables under study influenced the irradiance (P < 0.05) but not the curing depth (P > 0.05). The 3 groups that did not have the PVC film and either did not have the OBG or had the OBG in a thickness of 1 or 2 mm were not significantly different from each other (P > 0.05) but presented the highest irradiance values among all the groups (P < 0.05). The use of the misfit PVC film with a 3-mm layer of OBG led to the lowest irradiance values (P < 0.05). The variables did not influence each other (P > 0.05). The results of this study indicated that the presence of PVC film, especially misfit film, reduced the irradiance. In addition, the greater the thickness of the OBG, the lower the irradiance. None of the PVC film barrier conditions or OBG thicknesses had an effect on the depth of cure.

Accuracy of different laboratory scanners for scanning of implant-supported full arch fixed prosthesis.

OBJECTIVE: This study evaluated the accuracy of different laboratory scanners (LS) for scanning of implant-supported full arch fixed prosthesis with different implant angulations. MATERIALS AND METHODS: Two maxillary models that are designed to receive an all-on-four implant retained prosthesis were fabricated then scanned using five different LS. The models were divided into two groups according to the angulation of the posterior implant (Group 1; 30° and group 2; 45°). Each group was then subdivided into five subgroups according to the type of LS, subgroup T; Medit T710, subgroup I; IneosX5, subgroup E; 3ShapeE4, subgroup A; Autoscan DS-Mix, and subgroup M; Ceramill Map600. An industrial 3D scanner was used as reference scanner, then each model was scanned with 5 LS 10 times. Trueness and precision were analyzed using Geomagic 3D analysis software. RESULTS: Both scanner type and implant angle had a significant effect on the trueness (p < 0.001). Significant interaction was found between the scanner type and implant angle (p < 0.001). For scanner type tukeys post hoc test revealed highest trueness with the 3Shape E4 (21.3 ± 2.1) and the medit T710 (22.6 ± 2.1) and least trueness with the shining 3D autoscan ds-mix (33.8 ± 3.0). Significantly better trueness was observed with the 30° than the 45° angle. Regarding precision, two-way ANOVA revealed significant effect of the scanner type only (p < 0.001). There were no significant differences between the 3Shape E4, medit T710, Ineos X5, and the Ceramill map600. However, all showed significantly higher precision values when compared to shining 3D autoscan ds-mix. CONCLUSIONS: All tested scanners showed results within the clinically acceptable range with 3ShapeE4 and Medit T710 showing the highest accuracy. CLINICAL SIGNIFICANCE: Tested scanners can be used for scanning of All-on-four implant supported prosthesis.

Ultra-translucent zirconia processing and aging effect on microstructural, optical, and mechanical properties.

OBJECTIVES: To evaluate the effect of the ceramic processing and aging method on the microstructure, optical, and mechanical properties of a third generation ultra-translucent zirconia, yttria partially stabilized zirconia (5Y-PSZ). METHODS: In-house discs were obtained through uniaxial and isostatic pressing an ultra-translucent Y-PSZ powder and sintering at 1450 °C for 2 h. As control, a commercial disc was milled from pre-sintered blocks fabricated with the same 5Y-PSZ powder through isostatic pressing and sintered under the same protocol. Discs were allocated into three groups according to aging condition as immediate (non-aged) and aged using autoclave or hydrothermal reactor at 134ºC for 20 h at 2.2 bar. Crystalline content and microstructure were evaluated using X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. Optical properties were determined using reflectance data to calculate the contrast ratio (CR) and translucency parameter (TP). Mechanical properties were assessed by Vickers hardness, fracture toughness and biaxial flexural strength tests. RESULTS: XRD spectra revealed a prevalence of cubic (70%) and tetragonal (30%) phases, and the SEM images showed a dense fully crystalline ceramic matrix for both materials. Crystalline content and microstructure of the in-house and commercial 5Y-PSZs were not affected by aging. As-sintered 5Y-PSZs demonstrated similar CR (~0.6) and TP (~18) values, as well as Vickers hardness (~14 GPa) and fracture toughness (~3.8 Mpa.m1/2), with no significant alteration after both aging methods. In-house and commercial Y-PSZs Weibull moduli ranged from 3.0 to 5.3. 5Y-PSZ processing methods resulted in similar characteristic strength after sintering (592-618 Mpa). While commercial 5Y-PSZ showed no significant influence of aging on strength, hydrothermal reactor aging significantly decreased the in-house Y-PSZ characteristic strength (474 Mpa). Both 5Y-PSZs demonstrated high reliability up to 300-Mpa strength missions, with no detrimental effect of aging (88-100%). SIGNIFICANCE: Irrespective of the processing method, ultra-translucent 5Y-PSZ showed high aging resistance and translucency stability, as well as strength corresponding to the indication up to short-span anterior prostheses.

Influence of the Length Ratio Between Second and Third Metatarsals After Modified Weil Osteotomy on Clinical Outcomes.

Metatarsalgia is a frequent foot disorder. The objective was to evaluate whether the length ratio between the second and the third metatarsals after Weil osteotomy influences clinical outcomes. This retrospective study included 37 patients (53 feet). Preoperative planning consisted of keeping the second metatarsal greater than or equal to the third metatarsal after Weil osteotomy of the second metatarsal or the second and third metatarsals. Based on postoperative weightbearing and digital AP radiographs after Weil osteotomy, we divided the patients into 2 groups: group 1, the second metatarsal was longer than or equal to the third metatarsal; and group 2, the second metatarsal was shorter than the third metatarsal. We investigated whether there were differences between the groups. In 35 (66%) feet, the second metatarsal was longer than or equal to the third metatarsal (group 1), and in 18 (34%) feet, the second metatarsal was shorter than the third metatarsal (group 2). Postoperative American Orthopaedic Foot and Ankle Society scores were 86.2 and 82.7, respectively (p = .32). Postoperative Visual Analog Scale scores were 1.26 and 1.67, respectively (p = .39). The sample showed 11.3% of transfer metatarsalgia to the third metatarsal. Group 1 had 9% of transfer metatarsalgia, whereas group 2 had 17% of transfer metatarsalgia (p = .40). The presence of a second metatarsal shorter than the third metatarsal, after Weil osteotomy of the second metatarsal or the second and third metatarsals, does not influence outcomes or incidence of transfer metatarsalgia to the third metatarsal.

Effect of processing methods on the chipping resistance of veneered zirconia.

OBJECTIVES: To evaluate the edge chipping resistance (ReA) and the fracture toughness (KC) of 3Y-TZP bilayers produced with the following materials/processing combinations: fluorapatite glass-ceramic applied on zirconia using the traditional layering and hot-pressing (press-on) techniques; feldspathic porcelain using rapid layer technology (RLT); and lithium disilicate glass-ceramic using CAD-on method. The influence of the cooling rate (slow and fast) was analyzed for layering and hot-pressing. METHODS: Bilayer bars (25x4x2 mm) were made following manufacturers' instructions. The edge chipping test was performed in an universal testing machine, using a coupled Vickers indenter. ReA was calculated dividing the critical load at fracture by the edge distance. Fracture toughness was calculated by a regression fit with a fixed slope of 1.5 correlating the critical chipping load regarding edge distance and also with indentation fracture (IF) method. Data were statistically analyzed using ANOVA and Tukey's test (α = 5%). RESULTS: ReA and KC was significantly higher for the CAD-on bilayers. RLT showed intermediate ReA means, and layering and hot-pressing techniques showed the lowest ReA values. For both processing methods there was no effect of the cooling protocol on the ReA and fracture toughness. CONCLUSIONS: There is a significant effect of the material/processing association on the edge chipping resistance and fracture toughness of the bilayers. There was no effect of the cooling protocol on the edge chipping resistance and fracture toughness for the specimens processed by both the layering and hot-pressing techniques.

Influence of different combinations of CAD-CAM crown and customized abutment materials on the force absorption capacity in implant supported restorations - In vitro study.

OBJECTIVES: To evaluate the force absorption capacity of implant supported restorations utilizing different CAD-CAM materials for the fabrication of crowns and customized abutments. METHODS: 80 titanium inserts were scanned to design customized abutments and crowns. The specimens were divided into four groups (n = 20/material): (Z): zirconia, (P): PEEK, (V): VITA Enamic, and (E): IPS e.max. Each group was subdivided into two subgroups according to customized abutment material: (Z) zirconia, and (P) for PEEK. For the assessment of force absorption, all specimens were loaded in a universal testing machine, applied loads curves were collected from the machine's software, and resulting loads curves were collected from forcemeter below the assembly. The slopes of all curves were analyzed using Two-way multivariate analysis of variance with pairwise comparisons using Tukey Post Hoc test (p < 0.05). RESULTS: The curve progression of the applied and resulting forces varied among the investigated materials for each specimen. For zirconia abutments, ZZ showed the highest slope values of the applied and resulting force curves, followed by EZ, VZ, and PZ demonstrating statistically significant differences (P < .001). As for PEEK abutments, ZP and EP showed the least slope values, followed by PP then VP demonstrating statistically significant differences (P < .001). For Zirconia and e.max crowns, using PEEK abutments significantly increased slope loss. As for PEEK and Vita Enamic crowns changing abutment material did not significantly affect slope loss. SIGNIFICANCE: Combining rigid crown materials with less rigid abutments might enhance their force absorption capacity. However, with less rigid crown materials a stiff substructure might be mandatory to preserve their force absorption behavior.

Effect of silica coating and laser treatment on the flexural strength, surface characteristics, and bond strength of a dental zirconia.

This study investigated the effect of irradiation with an erbium-doped yttrium aluminium garnet (Er:YAG) laser and coating with silica on the surface characteristics, bond strength, and flexural strength of dental zirconia. Three hundred and forty-three standard zirconia specimens were created, and 49 were assigned to each of seven surface treatment groups: (i) no treatment; Er:YAG laser (80 mJ/2 Hz) with pulse widths of 50 µs (ii), 100 µs (iii), 300 µs (iv), or 600 µs (v); or tribochemical silica coating at the partially sintered stage (vi) or after sintering was complete (vii). All specimens were sintered after the surface treatments, except for the group in which specimens were sintered before treatment. The study outcomes were roughness, surface loss, microshear bond strength (µSBS), and biaxial flexural strength (BFS). Mean roughness and surface loss values were significantly higher in specimens from irradiated groups than in those from silica-coated groups. Regarding µSBS, after aging, specimens from all experimental groups presented very low and similar µSBS values, irrespective of the surface treatment. Silica coating after sintering yielded the highest BFS (1149.5 ± 167.6 MPa), while coating partially sintered specimens with silica resulted a BFS (826.9 ± 60.9 MPa) similar to that of the untreated control group (794.9 ± 101.7 MPa). Laser treatments, irrespective of pulse width used, significantly decreased the BFS. In the group treated with laser at 300 µs pulse width, specimens exhibited the lowest BFS value (514.1 ± 71.5 MPa). Adhesion to zirconia was not stable after aging, regardless of the surface treatment implemented.

Alumina-toughened zirconia for dental applications: Physicochemical, mechanical, optical, and residual stress characterization after artificial aging.

To characterize the physicomechanical properties of an alumina-toughened zirconia (ATZ). ATZ synthesis consisted of the addition of alumina particles in an yttria-stabilized tetragonal zirconia polycrystals (3Y-TZP) matrix. Specimens were obtained by uniaxial and isostatic pressing ATZ and 3Y-TZP powders and sintering at 1600°C/1 h and 1550°C/1 h, respectively. Crystalline content and residual stress were evaluated using X-ray diffraction (XRD). Microstructure was characterized by scanning electron microscopy (SEM). Optical properties were determined by reflectance test. Mechanical properties were assessed by biaxial flexural strength test. All analyses were performed before and after aging (134°C, 20 h, 2 bar). XRD and SEM revealed a typical ATZ and 3Y-TZP crystalline content, chiefly tetragonal phase, with a dense polycrystalline matrix, though a smaller grain size for ATZ. Aging triggered a similar monoclinic transformation for both systems; however, ATZ exhibited higher residual compressive stresses than 3Y-TZP. While as-processed 3Y-TZP demonstrated significantly higher characteristic strength relative to ATZ, no significant difference was observed after aging (~215 MPa increase in the ATZ strength). ATZ presented significantly higher opacity relative to 3Y-TZP, although aging significantly increased the translucency of both systems (increase difference significantly higher in the 3Y-TZP compared to ATZ). ATZ physicomechanical properties support its applicability in the dental field, with a lower detrimental effect of aging relative to 3Y-TZP.

Influence of Er:YAG laser surface treatment on flexural and bond strengths to glass-infiltrated zirconia-reinforced ceramic.

To evaluate the effect of Er:YAG laser conditioning of a glass-infiltrated alumina-based zirconia-reinforced ceramic on its flexural strength and on bonding to a resin cement. Sixteen blocks (5 × 5 × 4 mm) and 50 discs (Ø 12 mm, 1 mm thickness) of In-Ceram Zirconia (ICZ) obtained from CAD-CAM blocks were infiltrated with glass. For the microtensile bond strength (µTBS) test, all blocks were treated with aluminum oxide (AOX) and divided into 4 groups (n = 4): G1 (AOX), no combined surface treatment; G2 (ROC), tribochemical silica-coating; G3 (EY200), Er:YAG laser 200 mJ/15 Hz; and G4 (EY250), Er:YAG laser 250 mJ/10 Hz. The ceramic blocks were silanated and cemented with a resin cement (Panavia F2.0/Kuraray) to composite resin blocks and subjected to the µTBS test. For the flexural strength evaluation, the discs were divided into 5 groups (n = 10) as described above, in addition to a control group (G5 - CTRL, mirror-polished without further treatment). Each surface treatment was submitted to qualitative evaluation under SEM. One-way ANOVA (α = 5%) revealed the highest bond strength value for EY200 with no significant difference from ROC. The groups AOX and EY250 showed similar µTBS values that were statistically lower than those of EY200. For flexural strength, ROC was the only group with significantly lower values when compared with the CTRL. The use of Er:YAG laser at 200 mJ/15 Hz can be considered an innovative and effective alternative for surface conditioning of ICZ since it did not reduce the flexural strength of the ceramic and improved the resin cement bond to this substrate.

Construção do guia de plantas medicinais de Florianópolis, SC, Brasil / Production of the guide to medicinal plants in Florianópolis, Santa Catarina, Brazil / Construcción de la guía de plantas medicinales de Florianópolis, Estado de Santa Catarina, Brasil

Há escassez relativa de experiências com plantas medicinais e de orientações para confecção de materiais didáticos sobre elas na Atenção Primária à Saúde (APS). Uma equipe interinstitucional (Universidade Federal de Santa Catarina e Secretaria Municipal de Saúde de Florianópolis) produziu um guia de plantas medicinais em Florianópolis, SC. O objetivo deste trabalho é apresentar essa experiência e o guia, que é voltado para profissionais da APS e que valorizou saberes científicos, populares e profissionais, evitando uma abordagem colonizadora do tema. Após alguns tópicos introdutórios, o guia apresenta 38 plantas medicinais comumente usadas em Florianópolis (nomes científicos e populares; partes usadas; fotos; características botânicas; uso popular; informações científicas; uso clínico; modo de usar; reações adversas e contraindicações; plantas na gestação; toxicidade; glossário; e referências). Espera-se contribuir para a construção de outros guias adaptados aos contextos locais e para a valorização do uso de plantas medicinais na APS. (AU)

Experiences with medicinal plants and guidance for producing educational resources about these plants for use in primary health care (PHC) are relatively scarce. A team from the Santa Catarina Federal University and Florianópolis City Council Department of Health produced the "Guide to Medicinal Plants in Florianópolis". This article presents this experience and the guide, which is aimed at PHC professionals and values scientific, traditional and professional knowledge, avoiding a colonizing approach to the topic. After presenting some introductory topics, the guide describes 38 medicinal plants commonly used in Florianópolis (scientific and common names, parts used, photo, botanical characteristics, common uses, scientific information, clinical use, adverse reactions and contraindications, plants during pregnancy, toxicity, glossary and references). It is hoped this guide will contribute to the production of other guides adapted to local contexts and recognition of the value of medicinal plants in PHC. (AU)

Hay una escasez relativa de experiencias con plantas medicinales y de orientaciones para la confección de materiales didácticos sobre ellas en la atención primaria de la salud (APS). Un equipo interinstitucional (Universidad Federal de Santa Catarina y Secretaría Municipal de Salud de Florianópolis) produjo una guía de plantas medicinales en Florianópolis, estado de Santa Catarina. El objetivo de este trabajo es presentar esa experiencia y la guía, dirigida a los profesionales de la APS y que valorizó saberes científicos populares y profesionales, evitando un abordaje colonizador del tema. Después de algunos tópicos de introducción, la guía presenta 38 plantas medicinales comúnmente utilizadas en Florianópolis (nombres científicos y populares, partes usadas, foto, características botánicas, uso popular, informaciones científicas, uso clínico, modo de usar, reacciones adversas y contraindicaciones, plantas en la gestación, toxicidad, glosario y referencias). Se espera contribuir para la construcción de otras guías adaptadas a los contextos locales y para la valorización del uso de plantas medicinales en la APS. (AU)

Effect of titania addition and sintering temperature on the microstructure, optical, mechanical and biological properties of the Y-TZP/TiO2 composite.

OBJECTIVE: The aims of this study were: 1) to evaluate the effect of sintering temperature on microstructure, density and flexural strength of a 3Y-TZP/TiO2 composite containing 12.5 wt% of TiO2 compared to 3Y-TZP specimens (control); 2) to compare 3Y-TZP with the experimental 3Y-TZP/TiO2 composite, both sintered at 1400 °C, with respect to the following parameters: optical properties, characteristic strength, Weibull modulus, fatigue behavior, induction of osteoblasts proliferation and differentiation (mineralization nodules formation). METHODS: The 3Y-TZP and 3Y-TZP/TiO2 powders were uniaxially pressed and sintered at 1200 °C, 1300 °C, 1400 °C or 1500 °C for one hour in a furnace. The microstructural analysis consisted of X-ray diffraction and scanning electron microscopy. The density was measured by the Archimedes' principle and the flexural strength was obtained by the biaxial flexure test. The optical properties were measured using a spectrophotometer operating in the visible light wavelength range. The step-stress accelerated life testing was performed by the pneumatic mechanical cycler and the biological behavior achieved by using osteoblast-like cells (Osteo-1 cell line). RESULTS: Tetragonal zirconia was identified in all groups and cubic zirconia was identified only at 3Y-TZP group. The addition of TiO2 decreased the values of density and flexural strength of the composite 3Y-TZP/TiO2 in relation to 3Y-TZP regardless of the sintering temperature. The color difference between the two materials was not significant regarding L*a*b* parameters. The composite showed higher probability of failure, and induced higher proliferation and differentiation than control. SIGNIFICANCE: The composite developed have good aesthetic and biologics properties. However, its microstructure and mechanical properties need to be improved for future dental implant applications.