PURPOSE:This in vitro study aimed to evaluate: (1) the effects of staining agent type and denture tooth material type on the color stability of newly developed milled and 3D-printed denture tooth materials compared with conventional polymethylmethacrylate (PMMA) denture teeth and (2) the effect of denture cleanser on the color stability of these materials. MATERIALS AND METHODS:A total of 200 disc specimens (4 mm thick, 10 mm diameter; shade A1) were fabricated from five denture tooth materials (n = 40 each): conventional PMMA (HP-Jet), milled CAD-CAM resins (Ivotion [SM-I], Candulor [SM-C]), and 3D-printed resins (Flexcera [AM-F], Straumann [AM-S]). Each group underwent two sequential procedures: staining followed by cleaning. Specimens were immersed in one of four staining solutions-deionized water (control), orange juice, coffee, or red wine-for a standardized period (n = 10 per solution/material). Color was measured at baseline, post-staining, and post-cleaning using a calibrated spectroradiometer. Color changes (ΔE00) were calculated using the CIEDE2000 formula. Cleaning was performed using denture cleaning tablets per the manufacturer's instructions. Statistical analysis included two-way ANOVA with interaction and Tukey post hoc tests for staining and material effects, and repeated-measures comparisons with Šídák adjustment for the effect of cleaning (α = 0.05). RESULTS:Both material type and staining agent significantly influenced color change (p < 0.05). Most groups showed perceptible but clinically acceptable discoloration (ΔE00 > 1.2 and < 2.7). SM-C and AM-F exposed to orange juice exhibited minimal changes (ΔE00 < 1.2). AM-F stained with red wine showed the highest color change (ΔE00 = 4.49 ± 0.73), exceeding clinical thresholds. No significant differences were observed among materials stained with orange juice or coffee (p > 0.05). Cleaning significantly reduced ΔE00 values (p < 0.05), especially for most of the wine-stained specimens, with several groups achieving post-cleaning ΔE00 < 1.2. CONCLUSIONS:The color stability of denture tooth materials is influenced by both resin type and staining agent. While most materials demonstrated perceptible yet clinically acceptable discoloration, red wine caused significant staining, particularly in 3D-printed AM-F. Cleaning was effective in reducing discoloration, often restoring color to imperceptible levels.

STATEMENT OF PROBLEM:Research on the mechanical performance, particularly the fracture resistance, of recently introduced glass-composite and hybrid ceramic resin materials used with additive manufacturing (AM) and subtractive manufacturing (SM) techniques, and indicated for definitive restorations, remains limited. PURPOSE:The purpose of this in vitro study was to evaluate and compare the fracture resistance of AM or SM crowns in different resin-based materials through fatigue cyclic loading and load-to-fracture testing. MATERIAL AND METHODS:A standardized maxillary molar preparation was used to fabricate a zirconia master die, which was then scanned and reproduced in resin using a digital light processing (DLP) 3-dimensional (3D) printer. Two resins for AM (Pro Resins Crown X and Flexcera Smile Ultra+) and 2 resins for SM (Shofu HC and Brilliant Crios), all containing inorganic fillers (glass or ceramic), were used to fabricate identical computer-aided design (CAD) crowns (n=15). These crowns were then cemented using a standard protocol. Specimens underwent fatigue cyclic loading via 1.2 million cycles at 49 N, followed by the load-to-fracture test using a universal testing machine. Statistical analysis included 1-way ANOVA and the Tukey post hoc test (α=.05). RESULTS:All crowns withstood cyclic loading. A statistically significant difference in fracture load was observed across different crowns manufactured by using different resin-manufacturing technology pairs (P<.001). SM-S group exhibited the lowest fracture resistance (2184 ±660.2 N), whereas the other 3 groups exceeded 2500 N, with no significant differences among them (P>.05). CONCLUSIONS:AM crowns demonstrated fracture resistance comparable to SM crowns during and after fatigue cyclic loading and load-to-fracture tests. All crowns showed fracture resistance loads higher than previously reported clinically acceptable load values, supporting their potential for clinical use.

STATEMENT OF PROBLEM:Speed sintering techniques have been introduced to shorten the sintering time of zirconia ceramics, yet their impact on multilayered zirconia properties remains understudied. PURPOSE:The purpose of this in vitro study was to assess the effect of speed sintering on the optical properties and the mechanical flexural strength of multilayered zirconia materials. MATERIAL AND METHODS:A total of 360 disks (Ø14 ±2 mm ×1.2 ±0.02 mm) were fabricated by following the International Organization for Standardization (ISO) 6872:2015 standard using 2 types of Vita A2 shade multilayered zirconia materials: IPS e.max ZirCAD Prime (ZP) and IPS e.max ZirCAD Prime Esthetic (ZPE). Each material comprised translucent (Tr), gradient l (Gr), and dentin (De) layers, with 60 disks per layer. Half were sintered using a standard sintering protocol and half using a speed sintering protocol. Biaxial flexural strength was accessed using a universal testing machine equipped with the Blue Hill Universal software program by following the ISO 6872:2015 standard, with 20 disks per subgroup. The spectrophotometric analysis of optical properties (contrast ratio [CR], translucency parameter [TP], and total transmittance [Tt%]) was performed using a dual-beam spectrophotometer (Ultrascan VIS) in accordance with the ISO 7491:2000 standard, with 10 disks per subgroup. The comparison of the optical properties and the mechanical flexural strength between the speed and standard protocol was analyzed using an unpaired t test (α=.05). RESULTS:Speed sintering reduced biaxial flexural strength in all ZP layers (P<.05) and in ZPE-Gr (P<.05). A statistically significant difference in the CR was observed in the ZP-Tr, ZP-Gr, and ZPE-Gr layers (P<.05). The TP of the ZP-Gr, ZP-De, and ZPE-Gr layers was significantly lower when using the speed sintering protocol. Tt% was significantly lower with speed sintering for both materials (P<.05). CONCLUSIONS:Speed sintering statistically changed both the optical (CR, TP, Tt%) and mechanical (flexural strength) properties of multilayered zirconia materials, but the differences may not be clinically relevant.

PURPOSE:To assess the fabrication trueness, precision, and internal fit of additively manufactured (AM) and subtractively manufactured (SM) resin-based definitive crowns. MATERIALS AND METHODS:A maxillary right first molar complete-coverage crown was designed and fabricated using 2 additively manufactured [Pro Resins Crown X (AM-S); Straumann USA LLC and Flexcera Smile Ultra+ (AM-F); Desktop Health] and 2 subtractively manufactured [Shofu HC (SM-S); SHOFU Dental Corp and Brilliant Crios (SM-C); Coltene/Whaledent AG] resins (n = 15). The crowns were scanned using an intraoral scanner (IOS) and then seated onto the abutment tooth and rescanned. Fabrication trueness was evaluated by superimposing test data (TD) over the reference crown and computing the root mean square (RMS, µm) error for overall, intaglio, and margin surfaces. Internal fit was evaluated by measuring the average gap distance between the crown and abutment tooth (µm) using a modified triple scan protocol (TSP) for overall, occlusal, and axial surfaces. One-way ANOVA followed by post hoc Tukey's comparison tests was used to analyze the data (α = 0.05). RESULTS:Significant differences were observed among the resin-based crown materials for trueness (RMS), precision deviation, and internal fit (p < 0.001). AM-F had the lowest intaglio RMS value. Margin RMS values for AM-F and AM-S were significantly lower than those for SM-C and SM-S (p < 0.001). SM-C and SM-S showed superior occlusal fit compared to AM-F and AM-S (p < 0.001). CONCLUSIONS:The type of CAD-CAM manufacturing method-additive or subtractive-significantly influenced the trueness and internal fit of resin-based definitive crowns.

This study evaluated the color stability of digitally fabricated complete dentures compared to conventional ones. Forty-five specimens were fabricated using 3 different manufacturing methods (injection mold, one-piece milling, and two-piece 3D printing and milling techniques), with 15 specimens per group. After implementing a standardized polishing protocol, each group was randomly subdivided into three subgroups (n = 5) and immersed in distilled water, coffee, and red wine for seven days at a controlled temperature of 37 °C. Color changes in denture teeth and base materials were evaluated utilizing VITA Easyshade and ImageJ software before and after immersion. Subsequently, all specimens underwent a manufacturer-recommended denture cleansing regimen for seven days, followed by a repeated staining cycle. Two-way ANOVA and Tukey post-hoc tests were used for statistical analysis (α = 0.05), while the prevalence of denture tooth shade change was reported descriptively. The finding revealed that coffee caused more discoloration than red wine. Milled specimens showed better color stability against red wine than conventionally fabricated dentures. While initial staining was noted, the cleaning protocol successfully restored the original colors. This pattern persisted with repeated staining, highlighting the importance of material selection and maintenance in maintaining denture aesthetics. Exposure to coffee and red wine leads to noticeable color changes in both denture teeth and base materials. The degree of staining depends on the specific material composition, highlighting the importance of selecting stain-resistant materials for better long-term color stability.

Purpose: To assess the flexural strength (FS), surface roughness, and color stability of additive manufactured (AM) and subtractive manufactured (SM) denture teeth materials, as well as the effect of thermocycling on these properties. Materials and Methods: Eighty strips (20/material type; 64x10x3.3 mm) and 60 discs (15/material type; 12x4 mm) were fabricated from four different denture teeth materials (Straumann, Flexcera, Ivoclar, and Candulor). The specimens were divided into two subgroups (nonthermal cycled and 5000 thermal cycled,10 per subgroup), and subjected to a 3-point test for FS using a universal testing machine at a crosshead speed of 5.0 mm/min. Surface roughness (R-a, mu m) and color differences (Delta E-00) of disc specimens were measured before and after thermocycling using a noncontact optical profilometer and a spectrophotometer, respectively. The CIEDE2000 formula was used to calculate the color differences (Delta E-00) before and after thermocycling. Data were analyzed using 2-way ANOVA followed by post hoc multiple comparison tests (alpha = 0.05). Results: There was no significant difference in flexural strength between nonthermal cycled SM materials (p = 0.15), which were significantly higher than AM materials (p < 0.001). The flexural strength values of all tested materials were significantly reduced after thermocycling (p < 0.05). The material type had a significant effect on the R-a values (p < 0.001), whereas thermocycling did not (p = 0.81). After thermocycling, all materials exhibited color changes lower than the clinical perceptible threshold (Delta E-00 = 2.7). Conclusions: Thermocycling decreased the FS of denture teeth materials manufactured with AM and SM, but did not affect the surface roughness. The FS values of SM groups were significantly higher than AM materials, irrespective of thermocycling. No clinically significant color changes of the denture teeth material were noted.

Purpose: This study aimed to investigate the tensile bond strength between soft relining materials and different denture base materials. Materials and Methods: The study was conducted in accordance with ISO 23401:2023. A total of 288 rectangular specimens (10L x 10H x 20W mm) were fabricated from various denture base materials, including a heat-compression polymethylmethacrylate (PMMA), two types of milled PMAA, and three types of 3D-printed resins, with bonding using two chairside soft reline materials (Coe-Soft and Lynal). Specimens were placed in distilled water for 24 h before applying tensile force at a 5 mm/min crosshead speed. The tensile bond strength values (MPa) were calculated at maximum tensile force (N) before failure. Two-way ANOVA and post hoc multiple comparison tests were used to assess the effect of denture base and soft reline materials on the tensile bond strength (alpha = 0.05). Results: A significant difference in the tensile bond strength was found among the different types of denture base materials (p < 0.001), regardless of relining material type. Lynal-relined milled IvoBase demonstrated the highest tensile bond strength (0.5 +/- 0.06 MPa), followed by Lynal-relined milled Lucitone (0.44 +/- 0.03 MPa), both of which are clinically acceptable as they are equal or greater 0.44 MPa. The lowest tensile bond strength was detected in Lynal-relined 3D printed FotoDent (0.09 +/- 0.02 MPa). Lynal exhibited significantly higher tensile bond strength (p < 0.05) than Coe-Soft soft reline material when bonded to PMMA bases; however, there was no significant difference between Lynal and Coe-Soft when bonded to 3D-printed base materials (p > 0.05). Conclusions: The tensile bond strength between soft relining materials and denture bases is material-dependent, influenced by both the type of denture base material and the type of soft relining material used.

PURPOSE:To evaluate fracture load values of five types of interim CAD/CAM crowns with and without thermocycling.MATERIALS AND METHODS:A complete coverage crown was designed on a mandibular first molar with a uniform 1.5-mm axial and occlusal reduction, and the STL file was exported to manufacture 100 crowns using five materials (20 crowns per material): ZCAD Temp Esthetic (SM-ZCAD; Harvest Dental); Telio CAD (SM-TCAD); P pro Crown and Bridge (AM-PPRO); E-Dent 400 C&B MHF (AM-EDENT); and DENTCA Crown & Bridge (AM-DENTCA). Each group was then divided into two subgroups: before and after thermocycling (10 cornws per subgroup). The STL file of the mandibular first molar die was used to manufacture 100 resin dies. Each die was assigned to one interim crown. Interim crowns were then luted to their assigned die using a temporary luting agent. The fracture strength of crowns was then assessed using a universal testing machine at a crosshead speed of 2 mm/minute. Two-way ANOVA followed by Tukey multiple comparations post-hoc tests were used to assess the effect of material choice and thermocycling process on the fracture strength of interim crowns (α = .05).RESULTS:Material choice and the thermocycling process exerted a significant (P < .001) impact on the fracture strength of interim crowns. However, the interaction between these two factors did not yield a statistically significant effect (P = .176).CONCLUSIONS:Within the limitations of this study, the type of interim materials and thermocycling process have a significant impact on the fracture strength of interim crowns.

STATEMENT OF PROBLEM:The impact of thermal cycling on the flexure strength of contemporary denture base materials remains inadequately understood despite its crucial role in determining the long-term performance of complete dentures. PURPOSE:The purpose of this in vitro study was to evaluate the flexural strength of different CAD-CAM denture base materials and the effects of thermal cycling. MATERIAL AND METHODS:A total of 120 rectangular specimens were fabricated from 6 denture base materials according to the International Organization for Standardization (ISO) 20795-1:2013 standard: a heat-compressed PMMA ([Lucitone 199 [C-L199]), 2 brands of milled material (Ivotion Base [M-IB] and Lucitone Digital Fit [M-LDF]), and 3 types of 3- dimensionally (3D) printed material (Lucitone Digital Print [P-LDP], Flexcera Base [P-FB], and FotoDent Dentures [P-FD]). Specimens were divided into 2 subgroups of 10; half underwent thermocycling, half did not. Thermally cycled specimens were immersed in distilled water at 37 °C for 2 days, followed by 5000 thermal cycles at 5 and 55 ºC, with a dwell time of 30 seconds. They were then subjected to a 3-point flexural strength test. Two-way ANOVA, followed by post hoc Tukey multiple comparison tests were used to assess the effect of material type and the thermal cycling process on the flexural strength of denture base materials (α=.05). RESULTS:All materials met the ISO standard of 65 MPa flexural strength, except for thermal cycled P-FB. A significant difference (P<.05) in flexure strength value was found among various denture base materials without thermal cycling (M-LDF>M-IB≈P-FD≈P-LDP>C-L199≈ P-FB) and with thermal cycling (M-LDF> M-IB≈P-FD>P-LDP≈C-L199>P-FB). The flexural strength of tested materials was reduced significantly (P<.05) with thermal cycling. CONCLUSIONS:Three-dimensionally printed denture base materials have a flexural strength value similar to or less than that of milled denture base materials. Thermal cycling impacts the flexural strength of denture base materials.

Purpose: This study compared the fracture strength of single lithium disilicate implant-supported crowns fabricated on two-piece abutments with various materials: ceramic-reinforced PEEK, zirconia, and lithium disilicate. Materials and Methods: Thirty-six implants were embedded in acrylic cylinders. A two-piece abutment and a crown were designed following a pre-operation scan for a maxillary left central incisor. The designed crown was used to fabricate 36 lithium disilicate crowns. The designed abutment was used to manufacture 36 abutments from 3 materials, 12 each: (A) zirconia; (B) lithium disilicate; and (C) ceramic-reinforced PEEK. Abutments were surface treated and bonded on the titanium base abutments with resin cement. Then, lithium disilicate crowns were bonded on the assigned abutments. Specimens were then subjected to dynamic loading for 1,200,000 cycles. The fracture strength (N) of the assembly was assessed using a universal testing machine. One-way ANOVA followed by multiple comparison tests was used to evaluate the effect of abutment material on the fracture strength of single implant-supported restorations at a significance of .05. Results: The average fracture strength for the groups with zirconia, PEEK, and lithium disilicate two-piece abutments were 1362N +/- 218N, 1235N +/- 115N, and 1472N +/- 171N, respectively. There was a significant (p < 0.05) difference in fracture strength among the groups. The lithium disilicate group had significantly higher fracture strength (p = 0.0058) than the group with PEEK; however, there was no significant (p > 0.05) difference between the other groups. Conclusions: Two-piece abutments restored with lithium disilicate crowns investigated in the study have the potential to withstand the average physiological occlusal forces in the anterior region.

WRKY transcription factors (TF) control a variety of biological processes in higher plants, including abiotic and biotic stress responses. WRKY genes have been identified and functionally characterized in many plant species during the past ten years, but despite this progress, few investigations have focused on this TF family in licorice (Glycyrrhiza uralensis Fisch.). This study identified 72 WRKY genes from the licorice genome and classified them into three groups. The gene structure analysis indicated that the GuWRKY genes contain from one to eight introns, with the majority having two introns and three exons. Conserved motif analysis identified the conserved WRKY domain in most GuWRKYs. Further analysis of the promoter region revealed that almost all GuWRKYs had plant hormone- or stress-responsive cis-regulatory elements, with differences in the number of elements among the groups. The role of 10 selected GuWRKYs in regulating abiotic stress responses was further explored via quantitative real-time PCR (qRT-PCR) after low-temperature (4 degrees C), salt (150 mmol center dot L-1 NaCl), drought (15% polyethylene glycol 6000) treatments at 3, 6, 12, and 24 h. Thus, our study of the WRKY gene family in licorice provides a basis for further research on the structure and function of WRKY genes.

PURPOSE:To assess the shade match ability of four varieties of all-ceramic crowns to a neighboring bilayered lithium disilicate crown. MATERIAL AND METHODS:A dentiform was used to fabricate a bilayered lithium disilicate crown on the maxillary right central incisor, following the anatomy and shade of a selected natural tooth. Two crowns (one full-contour, one cutback) were then designed on a prepared maxillary left central incisor, following the contour of the neighboring crown. The designed crowns were used to manufacture monolithic lithium disilicate, bilayered lithium disilicate, bilayered zirconia, and monolithic zirconia crowns, 10 each. An intraoral scanner and a spectrophotometer were used to assess the frequency of matched shades and to calculate the color difference (ΔE) between the two central incisors at the incisal, middle, and cervical thirds. Kruskal-Wallis and two-way ANOVA were used to compare the frequency of matched shades and ΔE values, respectively (α = 0.05). RESULTS:There was no significant (p > 0.05) difference in frequencies of matched shades for each group at the three sites; except bilayered lithium disilicate crowns. Bilayered lithium disilicate crowns had significantly (p < 0.05) higher match frequency than monolithic zirconia at the middle third. The ΔE value was not significantly (p > 0.05) different among the groups at the cervical third. However, monolithic zirconia had significantly (p < 0.05) higher ΔE values than bilayered lithium disilicate and zirconia at the incisal and middle thirds. CONCLUSIONS:Bilayered lithium disilicate and zirconia appeared to most closely match the shade of an existing bilayered lithium disilicate crown.

Abstract Oral mucosal colonization by C. albicans (Ca) is benign in healthy people but progresses to deeper infection known as oropharyngeal candidiasis (OPC) that may become disseminated when combined with immunosuppression. Cortisone-induced immunosuppression is a well-known risk factor for OPC, however the mechanism by which it permits infection is poorly understood. Neutrophils are the primary early sentinels preventing invasive fungal growth, and here we identify that in vivo neutrophil functional complexes known as swarms are crucial for preventing Ca invasion which are disrupted by cortisone. Neutrophil swarm function required leukotriene B4 receptor 1 (BLT1) expression, and swarms were further characterized by peripheral association of polymorphonuclear myeloid-derived suppressor cells (PMN-MDSCs) showing that OPC recruits PMN-MDSCs to this site of infection. Furthermore, PMN-MDSCs associated with Ca hyphae had no direct antifungal effect but showed prolonged survival times and increased autophagy. Thus in vivo neutrophil swarms are complex structures with spatially associated PMN-MDSCs that likely contribute immunoregulatory functions to resolve OPC. These swarm structures have an important function in preventing deep invasion by Ca within the oral mucosa and represent a mechanism for increased disease severity under immune deficient clinical settings.

STATEMENT OF PROBLEM:Custom-made angled LOCATOR abutments have been used to compensate for the angulation of implants placed to support removable prostheses; however, their retention forces and the impact of mastication loading on retention have yet to be well addressed.PURPOSE:The purpose of this in vitro study was to evaluate the retention force of custom-made LOCATOR abutments for implants placed at 0-, 15-, and 30-degree angulations with prefabricated abutments and to investigate the effect of mastication load on retention.MATERIAL AND METHODS:Implant analogs were placed at the first molars of 40 maxillary typodonts, and 40 LOCATOR abutments were fabricated. Twenty implant analogs were placed at 0 degrees, 10 of which received prefabricated LOCATOR abutments and 10 of which received custom abutments. The remaining 20 implant analogs were placed at 15- and 30-degree angulations (n=10), and custom LOCATOR abutments were fabricated on them. A denture analog was digitally designed and manufactured from polymethyl methacrylate (PMMA) billets. Metal housings were then picked up using PMMA. The specimens were subjected to 2 rounds of 120 000 cycles of mastication loading. Retention force was assessed before and after each round of mastication loading using a universal testing machine. The wear of nylon inserts before and after mastication loading was accessed with a digital stereomicroscope. A 2-way ANOVA followed by the Tukey HSD test was used to determine the impacts of LOCATOR abutment type and times of mastication loading on the retention forces of the denture base (α=.05).RESULTS:No significant difference in retention forces was found between prefabricated LOCATOR and custom abutments (placed at 0-, 15-, and 30-degree angulations) regardless of mastication loading (P>.05). The retentive force values of all groups increased significantly after the first round of mastication loading and decreased significantly to the initial level after the second round of mastication loading (P<.05).CONCLUSIONS:Mastication loading impacted the retention force of both prefabricated and custom LOCATOR abutments; however, no significant difference in retention forces was found among various types of abutments.

This study assessed the effect of Bacillus megaterium on seedling growth of Glycyrrhiza uralensis Fisch. under control and phosphorus (P) deficiency conditions. The results showed that P deficiency improved 1) G. uralensis root growth, 2) superoxide dismutase, catalase, and peroxidase activities, 3) inorganic P, starch, and soluble sugar contents in roots, 4) dissipated energy flux per reaction center, trapped energy flux per reaction center, and absorption flux per reaction center, and 5) net photosynthetic rate, stomatal conductance, transpiration rate, maximum fluorescence intensity after dark adaptation, and variable fluorescence. However, P deficiency significantly decreased chlorophyll and carotenoid contents in G. uralensis, but enhanced chlorophyll and carotenoid contents in B. megaterium. Our findings on the regulatory mechanisms of B. megaterium in response to P starvation hold promise for improving the success of G. uralensis cultivation. Keywords: Bacillus megaterium; Glycyrrhiza uralensis Fisch; Phosphorus deficiency; Chlorophyll fluorescence; Antioxidant enzymes superoxide; Non-structural carbohydrate

Purpose This in vitro study aimed to compare flexural strength, surface roughness, and biofilm formation of ceramic-reinforced polyetheretherketone (PEEK) with conventionally heat-compressed and milled polymethylmethacrylate (PMMA) denture base materials.Materials and Methods Thirty strips (6.4 mm x 10 mm x 3 mm) and 30 discs (10 mm x 1 mm) were fabricated from a heat-compressed PMMA, milled PMMA, and ceramic-reinforced PEEK, 10 each. One surface of each sample was polished to mimic the laboratory procedure for denture base materials. Strips were then subjected to a three-point bend test using a universal testing machine at a crosshead speed of 5.0 mm/min. An optical profilometer was used to assess the Ra value (mm) of the discs on polished and unpolished sides. Biofilm formation behavior was analyzed by measuring the colony-forming unit (CFU)/mL of Candida albicans on the unpolished surface of the discs. One-way ANOVA followed by Tukey multiple comparison tests were used to compare the flexural strength, Ra value, and biofilm formation of the studied materials (a = 0.05).Results Ceramic-reinforced PEEK showed significantly higher flexural strength (178.2 +/- 3.2 MPa) than milled PMMA (89.6 +/- 0.8 MPa; p < 0.001) and heat-compressed PMMA (67.3 +/- 5.3 MPa; p < 0.001). Ceramic-reinforced PEEK exhibited a significantly higher Ra value than the other groups on unpolished sides; however, the polishing process significantly reduced the Ra values of all studied groups (p < 0.05). There was no significant difference in C. albicans adhesion among the groups (p < 0.05).Conclusion The flexural strength of tested materials was within acceptable limits for clinical use as a denture base material. Ceramic-reinforced PEEK had the highest surface roughness; however, its similarity in biofilm formation to other groups indicates its clinical acceptability as denture base material.

STATEMENT OF PROBLEM:Novel 3-dimensionally printed resin and milled polymethyl methacrylate materials have been marketed for computer-aided design and computer-aided manufacturing (CAD-CAM) denture base fabrication. However, information on the flexural strength of digitally fabricated denture base material is limited, and little is known about how they are affected by a hard-reline procedure. PURPOSE:The purpose of this in vitro study was to assess the flexural strength of 6 digitally manufactured denture base materials and to assess the effect of a hard-reline procedure on their flexural strength. MATERIAL AND METHODS:A total of 140 strips of denture base material were fabricated from a conventional heat-polymerized polymethyl methacrylate (L199), 3 brands of milled polymethyl methacrylate (IBC, DSL, and ADH), and 3 brands of 3D-printed resin (DFD, ADB, and DrFD) (n=20). Ten specimens in each group did not receive any treatment, and 10 were relined with a hard-reline material (ProBase Cold Trial Kit). Specimens were then subjected to a 3-point flexural strength test using a universal testing machine at a crosshead speed of 5.0 mm/min. A 1-way ANOVA test followed by the Tukey multiple comparison test was used to detect the difference in flexural strength and the strain at fracture of the different types of denture base materials (α=.05). The comparison of flexural strength between with and without hard-reline was analyzed using an unpaired t test (α=.05). RESULTS:All materials, with or without the hard-reline, met the International Organization for Standardization (ISO) 20 795-1:2013 standard for flexural strength (65 MPa). The milled materials (DSL>IBC≈ADH) showed higher flexural strength than the 3D-printed or conventional materials (DrFD>DFD≈ADB≈L199) without a hard-reline. No statistical difference in flexural strength was found among the hard-relined denture base materials (P=.164). All 3 milled materials showed reduced flexural strength after relining, while the relined conventional (L199) and 3D-printed materials (DFD and ADB) showed notably higher flexural strength; printed DrFD showed no significant difference (P=.066). In terms of strain at fracture, the milled materials displayed higher values than those of the conventional or 3D-printed materials (P<.05). CONCLUSIONS:All digitally fabricated denture base materials were within acceptable limits for clinical use, even after hard relining. Flexural strength was highly dependent on the type of material. Hard relining affected the flexural strength of most of the digitally fabricated denture base materials.

富组蛋白是存在于人类唾液中的一种抗菌肽,可作为宿主非免疫防御系统的重要组成部分.富组蛋白5作为最有效的抗菌肽之一,与口腔念珠菌病、牙周病、龋病等多种口腔疾病相关联,其具有参与抗真菌、抑制细菌生长与定植、抑制宿主蛋白酶和细菌蛋白酶等生物学活性,但作用机制尚不十分明确.因此,对唾液富组蛋白5的研究具有重要意义.文章就唾液富组蛋白5应用于口腔疾病的研究进展做一综述.

Purpose The purpose of the study was to assess participants' and presenters' perceptions of a live web-based lecture series in comparison to traditional in-person lectures. Materials and Methods A virtual lecture series was organized by the---from March 25th until June 3rd of 2020. Twenty-five postgraduate prosthodontics programs and 81 presenters participated. Two surveys were developed and distributed to the audience (N = 330) and the presenters (N = 81). Follow-up emails were sent one week, three weeks, and four weeks after the initial email survey to encourage its completion. The data were analyzed descriptively. One-way ANOVA (p = 0.05), followed by a post hoc test, were used to compare the response percentages among the different generations of presenters and participants. Results Fifty-two percent of participants, and 65% of presenters, completed the survey. More than 96% of participants and presenters were satisfied with the lecture series. Seventy-nine percent of audience members felt that the live web-based lectures were as effective as traditional classroom lectures, or more effective; 32% of presenters agreed. Millennial audience members had significantly (p = 0.0028) more negative responses than the other generations. Conclusion Participants have more positive perceptions of web-based lectures than presenters.

PURPOSE  To compare the fracture strength of three-unit provisional partial fixed dental prostheses (FDPs) fabricated by an indirect-direct technique from poly(methylmethacrylate) (PMMA) through digital and conventional workflows, and FDPs fabricated by a direct technique using Bisacryl (BisA) and externally reinforced BisA. MATERIALS AND METHODS  Forty partially edentulous typodonts with a missing mandibular left first molar and standard preparations on mandibular left second premolar and molar were used to fabricate three-unit provisional FDPs. Two materials and two techniques were used to fabricate a total of forty provisional FDPs: 1) BisA; 2) BisA reinforced with glass fiber strips [BisA-GFR]; 3) conventionally fabricated PMMA shell relined with PMMA [C-PMMA]; 4) CAD/CAM fabricated PMMA shell relined with PMMA [CAD/CAM-PMMA]. Provisional FDPs were then luted onto the preparations using a temporary cement. Specimens were mounted onto a chewing simulator; 20,000 cycles of 70N forces were applied under 25o C distilled water. Specimens were then loaded to fracture using a universal testing machine (The Dillion Quantrol TC2i; Mecmesin) with a crosshead speed of 2mm/min. One-way ANOVA, followed by Tukey post-hoc test, was used to assess the effect of production technique on the fracture strength of the provisional FPDs (α=0.5). RESULTS  Mean fracture strengths recorded for the CAD/CAM-PMMA, C-PMMA, BisA, and BisA-GFR groups were 520 N, 448 N, 245 N, and 169 N, respectively. PMMA groups had significantly (p<.0001; F=24.40) higher fracture strength compared to Bisacryl groups. CONCLUSION  When high occlusal forces are expected, provisional FDPs fabricated with PMMA using the indirect-direct technique are recommended, irrespective of CAD/CAM or conventional workflow. This article is protected by copyright. All rights reserved.