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Purpose: The study was intended to create a uniform zirconia layer even on the surface of complex structures via atomic layer deposition (ALD). The impact of crystalline zirconia deposited by ALD on bacterial adhesion and osteoblast viability was assessed via surface treatment of dental implants., Methods: Amorphous zirconia was deposited using an atomic layer deposition reactor (Atomic Classic, CN1, Hwaseong, Korea) on titanium discs. Heating the samples at 400°C resulted in crystallization. Samples were divided into three groups: the control group, the group carrying amorphous ALD-zirconia (Z group), and the heat-treated group following zirconia ALD deposition (ZH group).The surface of each sample was analyzed, followed by the assessment of adhesion of Streptococcus mutans and Porphyromonas gingivalis , and viability and differentiation of MC3T3-E1 cells., Results: The adhesion of S. mutans and P. gingivalis was significantly reduced in the Z and ZH groups compared with the control group (P < 0.05). The viability of MC3T3-E1 cells was significantly increased in the ZH group compared with the control group (P < 0.001), while no significant differences were observed in the Z group (P > 0.05). Differentiation of MC3T3-E1 cells showed a marginally significant increase in the ZH group compared with the control group (P < 0.1), while no significant differences were found in the Z group (P > 0.1)., Conclusion: Compared with the pure titanium group, the groups that were coated with zirconia via ALD showed a decreased adhesion of S. mutans during the early stages of biofilm formation and P. gingivalis adhesion inducing peri-implantitis, and an increase in MC3T3-E1 cell viability and differentiation. The findings indicate the possibility of treating the implant surface to reduce peri-implantitis and improve osseointegration., Competing Interests: The authors report no conflicts of interest in this work., (© 2021 Jo et al.)

Statement of Problem: Although many systems are used to polish zirconia, a comparison of the performance of zirconia and feldspathic porcelain polishing systems is lacking., Purpose: The purpose of this in vitro study was to compare the effects of 3 polishing systems on surface roughness, zirconia phase transformation, and durability of the polishing systems when applied to zirconia and feldspathic porcelain., Material and Methods: Three polishing systems were evaluated: Z1, a zirconia polishing system; Z2, a zirconia polishing system, and F1, a feldspathic porcelain polishing system. Three ceramic systems were evaluated: PR and ZM zirconia specimens (diameter 15 mm, height 2 mm; 23 specimens each) and CB feldspathic porcelain specimens of the same size (15 specimens). A rough surface was created on the 3 types of specimens (15 specimens each) to model an occlusal adjustment under the same conditions. Polishing was carried out with the 3 polishing systems for 2 minutes each. Surface roughness was measured with a 3-dimensional (3D) optical profiler. The surface was also observed with a scanning electron microscopy. X-ray diffraction analysis was performed for 8 PR or ZM zirconia specimens polished by using the Z1 and Z2 systems for 8 minutes to evaluate the phase transformation of zirconia before, during, and after polishing. These specimens were compared and analyzed for phase transformation that might have occurred during the polishing of the specimens. After finishing the surface roughness experiment and the phase transformation experiment, the volumes of the polishers were measured with a 3D volume scanner and compared with those before the experiments to evaluate the durability of the polishing system. A statistical analysis of all data was performed using 2-way ANOVA and the Tukey honest significant difference test (α=.05)., Results: The 2 zirconia polishing systems (Z1, Z2) created a significantly (P<.001) smoother surface, regardless of the type of specimens used for polishing, than the feldspathic porcelain polishing system (F1). When polishing treatment was carried out on zirconia specimens for 8 minutes, the maximum percentages of monoclinic phase increased by 0.03% in the Z1 system and by 0.09% in the Z2 system. The volume change for the durability evaluation of the polishing system was 13.35 and 29.37% in the Z1 system, 2.05 and 5.92% in the Z2 system, and 3.60 and 4.95% in the F1 system, respectively., Conclusions: Zirconia polishing systems created a smoother surface on zirconia than the feldspathic porcelain polishing system. No significant changes in the phase transformation of zirconia were found before and after polishing. Each polishing system showed different levels of wear resistance., (Copyright © 2016 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

Objectives: Molecular mechanism of the pathogenicity of Enterococcus faecalis (E. faecalis), a suspected endodontic pathogen, has not yet been adequately elucidated due to limited information on its virulence factors. Here we report the identification of in vivo expressed antigens of E. faecalis by using a novel immunoscreening technique called change-mediated antigen technology (CMAT) and an experimental animal model of endodontic infection., Materials and Methods: Among 4,500 E. coli recombinant clones screened, 19 positive clones reacted reproducibly with hyperimmune sera obtained from rabbits immunized with E. faecalis cells isolated from an experimental endodontic infection. DNA sequences from 16 of these in vivo-induced (IVI) genes were determined., Results: Identified protein antigens of E. faecalis included enzymes involved in housekeeping functions, copper resistance protein, putative outer membrane proteins, and proteins of unknown function., Conclusions: In vivo expressed antigens of E. faecalis could be identified by using a novel immune-screening technique CMAT and an experimental animal model of endodontic infection. Detailed analysis of these IVI genes will lead to a better understanding of the molecular mechanisms involved in the endodontic infection of E. faecalis.

Statement of Problem: Although the application of zirconia in esthetic prostheses has increased, the shear bond strength (SBS) between colored zirconia and resin cement has not been investigated., Purpose: The purpose of this study was to compare the SBS between resin cement and colored zirconia made with metal chlorides., Material and Methods: Sixty-four zirconia specimens were divided into 2 groups: one in which the specimens were bonded with resin cement, including 4-META (4-methacryloxyethyl trimellitic anhydride), and one in which the specimens were bonded with resin cement (SEcure, Sun Medical) after being processed with zirconia primer (Zirconia Liner), including 4-META. Each group was then divided into 4 subgroups depending on the coloring liquid. The subgroups were noncolored (control), commercial coloring liquid VITA In-Ceram 2000 YZ LL1, aqueous chromium chloride solution 0.1 wt%, and aqueous molybdenum chloride solution 0.1 wt%. Composite resin cylinders (Filtek Z250, 3M ESPE) were fabricated and bonded to the surface of the zirconia specimen with resin cement (SEcure). All specimens were stored in 37°C distilled water for 24 hours, and the SBS was measured with a universal testing machine. All data were analyzed statistically with 2-way ANOVA and tested post hoc with the Tukey test (α=.05)., Results: Significant differences were observed among the SBS values of the colored zirconia depending on the coloring liquid (P<.001) and whether they were processed with zirconia primer (P<.001). The SBS between colored zirconia and resin cement was significantly higher than that of noncolored zirconia and resin cement in groups processed with zirconia primer (P<.05). Colored zirconia immersed in aqueous molybdenum chloride solution showed a significantly higher SBS., Conclusions: Coloring liquid enhanced the SBS between resin cement and zirconia processed with zirconia primer. In particular, colored zirconia immersed in aqueous molybdenum chloride solution showed the highest SBS., (Copyright © 2015 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

Statement of Problem: Little clinical information exists on the antagonist wear of anatomic contour zirconia crowns., Purpose: The purpose of this in vitro study was to evaluate the 2-body wear of antagonists for 3 computer-aided design and computer-aided manufacturing (CAD/CAM) anatomic contour zirconia ceramics and veneering porcelain when opposing natural human enamel., Material and Methods: Zirkonzahn Y-TZP (polished zirconia, zirconia with staining, zirconia with staining and glazing), Acucera Y-TZP, Wieland Y-TZP, and Noritake feldspathic ceramic were tested (6 groups). Eight disk-shaped specimens 15 mm in diameter and 5 mm thick were prepared for each group. Forty-eight specimens were fabricated for a wear test against maxillary premolars without caries or previous restorations with 240 000 masticatory cycles in a masticatory simulator. Before the experiment, the surface roughness of each ceramic was measured with a nanosurface 3-dimensional (3D) optical profiler. The surface of the specimens was observed at 50× and 1000× magnification with a field emission scanning electron microscope (FE-SEM) before and after the experiment. The data obtained were statistically analyzed by 1-way ANOVA and the Tukey test for post hoc analysis (α=.05)., Results: The SEM observations of each group revealed fine bubbles and porous surfaces in the Noritake feldspathic ceramic group, whereas the polished Zirkonzahn Y-TZP group, Acucera Y-TZP group, and Wieland Y-TZP group had smooth surfaces. The surface roughness of Zirkonzahn Y-TZP after staining and glazing was significantly greater than that of any other groups (P<.01). The tooth opposing the polished Zirkonzahn Y-TZP group demonstrated the least wear (1.11 ± 0.51 mm³), while Zirkonzahn Y-TZP with staining and glazing produced the greatest enamel wear (3.07 ± 0.98 mm³) among the zirconia groups. The Noritake feldspathic ceramic group showed significantly more antagonistic tooth wear than other groups (P<.05)., Conclusions: The antagonist wear of 3 CAD/CAM anatomic contour zirconia ceramics was significantly less than the Noritake veneering ceramic because the surface character of Y-TZP is relatively uniform and homogeneous. Zirkonzahn Y-TZP with staining and glazing was significantly more abrasive than the other zirconia specimens tested. However, it was less abrasive than the Noritake veneering ceramic., (Copyright © 2014 Editorial Council for the Journal of Prosthetic Dentistry. Published by Mosby, Inc. All rights reserved.)

Statement of Problem: Airborne-particle abrasion of the inner and outer surfaces of an yttria-stabilized tetragonal zirconia polycrystal (Y-TZP) core is used in an attempt to enhance the bond strength between the core and the veneering porcelain and to increase the surface area for cementation. However, airborne-particle abrasion introduces surface flaws that act as stress concentrators that may compromise the mechanical strength of the ceramic., Purpose: The purpose of this study was to investigate the effect of airborne-particle abrasion and heat treatment on the microstructure, biaxial flexural strength, and reliability of Y-TZP zirconia ceramics before veneering and cementation., Material and Methods: Forty-eight disks (15 mm in diameter, 0.5 mm in thickness) of Y-TZP were divided into 6 groups. Three treatments (untreated, airborne-particle abrasion, and heat treatment after airborne-particle abrasion) were applied to the upper surfaces, and 2 treatments (untreated and airborne-particle abrasion) were applied to the lower surfaces to mimic the preparation for veneering and cementation. For airborne-particle abrasion, 110 μm Al2O3 particles were used. The maximum load at fracture was calculated with a biaxial flexural strength test. The upper surfaces were facing the loading piston, and the lower surfaces were facing the supporting jig during testing. Results were analyzed with 2-way ANOVA (α=.05). The treated and fractured surfaces were observed with a scanning electron microscope. The relative content of the monoclinic phase was quantified with an x-ray diffraction analysis., Results: The group with airborne-particle abraded lower surfaces showed significantly higher flexural strength than the untreated group (P<.001). The SEM images of the airborne-particle abraded zirconia specimens showed rough and irregular surfaces. The fracture initiated from the tension side, which was opposite to the applied load., Conclusions: Within the limits of this in vitro study, the results showed that airborne-particle abrasion of the lower surfaces increases the flexural strength of Y-TZP zirconia., (Copyright © 2013 The Editorial Council of the Journal of Prosthetic Dentistry. Published by Mosby, Inc. All rights reserved.)

This study evaluated whether the combination of biodegradable β-tricalcium phosphate (β-TCP) scaffolds with recombinant human bone morphogenetic protein-2 (rhBMP-2) or platelet-rich plasma (PRP) could accelerate bone formation and increase bone height using a rabbit non-through cranial bone defect model. Four non-through cylindrical bone defects with a diameter of 8-mm were surgically created on the cranium of rabbits. β-TCP scaffolds in the presence and absence of impregnated rhBMP-2 or PRP were placed into the defects. At 8 and 16 weeks after implantation, samples were dissected and fixed for analysis by microcomputed tomography and histology. Only defects with rhBMP-2 impregnated β-TCP scaffolds showed significantly enhanced bone formation compared to non-impregnated β-TCP scaffolds (P < 0.05). Although new bone was higher than adjacent bone at 8 weeks after implantation, vertical bone augmentation was not observed at 16 weeks after implantation, probably due to scaffold resorption occurring concurrently with new bone formation.

A patient developed contact mucositis after being treated with a titanium nitride implant abutment. Patch testing disclosed a positive reaction to titanium nitride. After removal of the titanium nitride-coated abutment and placement of an uncoated abutment, all signs and symptoms disappeared. This clinical report suggests that titanium nitride-coated abutments may be a potential allergen in some patients., (Copyright © 2012 The Editorial Council of the Journal of Prosthetic Dentistry. Published by Mosby, Inc. All rights reserved.)

Statement of Problem: Titanium is an alternative tooth restorative material because of a its biocompatibility and mechanical properties. However, there is little information on the marginal accuracy of a complete titanium crown with different margin configurations., Purpose: This study examined the effect of fabrication method and margin configuration on the marginal and internal fit of complete titanium crowns., Material and Methods: An acrylic resin maxillary first molar was prepared with shoulder (buccal), chamfer (palatal), and knife edge (proximal) margin configurations. Forty crowns were produced and then divided into 2 groups according to the manufacturing method (casting method or CAD/CAM technique) (n=20). Each crown was luted to the original stone die with zinc phosphate cement. The margin of the crown, center point of the axial wall, and occlusal area were measured with a 3-dimensional measuring microscope. An independent t-test (internal gap) and repeated measures 2-way ANOVA (marginal gap) were used for statistical analysis (α=.05)., Results: The mean marginal gap of the cast group was significantly smaller than that of the CAD/CAM group (P<.001). The margin configuration affected the measured marginal discrepancy (P<.001). In both groups, the mean marginal gap of the chamfer and shoulder margin was significantly smaller than that of the knife-edge margin (P<.001)., Conclusions: Castings-produced titanium crowns with a better marginal fit than the CAD/CAM technique. The knife-edge margin exhibited the greatest marginal discrepancy., (Copyright © 2011 The Editorial Council of the Journal of Prosthetic Dentistry. Published by Mosby, Inc. All rights reserved.)

Statement of Problem: Various surface treatments of zirconia have been recommended for veneering ceramics. However, it has not been determined which of these treatments produces the highest bond strength., Purpose: This study examined the effects of various surface treatments on the shear bond strength of zirconia and veneering ceramic., Material and Methods: Square-shaped (5 × 10 × 10 mm) zirconia (Everest) specimens were divided into 4 groups (n=8) according to surface treatment as follows: group C, grinding with #320 diamond disc (control); group A, airborne-particle abrasion with 110 μm Al(2)O(3); group L, application of liner (Cerabien); and group AL, airborne-particle abrasion with 110 μm Al(2)O(3) and application of liner. A cylinder of veneering ceramic (2.4 mm in diameter and 3 mm in height) (Cerabien) was fabricated and fired on the zirconia specimens. The shear bond strength was tested using a universal testing machine. The data were analyzed statistically using a 1-way ANOVA and Tukey's multiple comparisons test (α=.05). The interface and fractured surfaces of the specimens were also evaluated by field emission scanning electron microscopy (FE-SEM)., Results: The mean and SD values for the shear bond strength of the groups ranged from 27.87 ± 3.59 MPa (for group L) to 36.63 ± 2.96 MPa (for group A). The 1-way ANOVA revealed a significant difference between groups (P=.001). The airborne-particle abrasion group showed significantly higher bond strength than liner applied groups (L, AL) (P<.05). The SEM revealed that liner-applied groups (L, AL) showed primarily adhesive failure. Complete delamination and microspaces were also observed in the liner-applied groups., Conclusions: The mean in vitro shear bond strength of veneering ceramic on zirconia treated with airborne-particle abrasion was significantly higher than that subjected to liner-applied treatments., (Copyright © 2011 The Editorial Council of the Journal of Prosthetic Dentistry. Published by Mosby, Inc. All rights reserved.)

Statement of Problem: It is difficult to achieve a reliable bond between the titanium copings and veneering porcelain of restorations., Purpose: The purpose of this study was to investigate the effect of various treatments on the fracture load of bonded titanium and porcelain components of crown restorations., Material and Methods: In this study, the surfaces of titanium copings (n=6) were either airborne-particle abraded with Al(2)O(3) particles, sputter coated with gold, or coated with TiN. Gold ceramic crowns served as the control group (n=6). The effects of these treatments on the fracture load of bonded titanium and low-fusing porcelain were investigated. A universal testing machine was used to determine the fracture load (N) of the crowns. All data were compared using 1-way ANOVA and the post hoc multiple range Tukey test (α=.05). In addition, the metal ceramic interfaces were examined by scanning electron microscopy (SEM) and energy dispersive x-ray spectroscopy (EDS)., Results: The gold-coated titanium (1035 +/-41 N) and TiN-coated titanium (969 +/-93 N) had significantly higher fracture loads (P<.001) than the airborne-particle-abraded titanium ceramic crowns (865+/-44 N). The gold-coated and TiN-coated titanium specimens demonstrated fracture loads similar to that of gold ceramic crowns (1026 +/-50 N) [corrected]. SEM/EDS showed that after the crowns fractured, the gold control group and gold- and TiN-coated titanium specimens had more adherent porcelain on their surfaces than the uncoated titanium that was airborne-particle abraded with Al(2)O(3) particles., Conclusions: The in vitro fracture load of titanium crowns coated with gold or titanium nitride and bonded to low-fusing porcelain is comparable to that of gold ceramic crowns, and higher than loads observed with uncoated titanium airborne-particle abraded with Al(2)O(3) particles., (Copyright © 2011 The Editorial Council of the Journal of Prosthetic Dentistry. Published by Mosby, Inc. All rights reserved.)

This study compared the shear bond strength and failure types of a polymethyl methacrylate (PMMA) denture base resin to commercially pure (CP) titanium, Ti-6Al-4V alloy, and cobalt-chromium alloy using a metal surface conditioner. The PMMA denture base resin (5 x 5 x 5 mm(3)) was cured onto disks, 10 mm in diameter and 2.5-mm thick. The shear bond strength of the PMMA resin with the surface conditioner was significantly higher than that without (P < .05). There was no significant difference between the types of metal. The conditioned specimens showed mixed failures, whereas the nonconditioned specimens exhibited only adhesive failure at the metal-resin interface.

A novel protocol for the synthesis of biocompatible and degradation controlled poly(lactic-co-glycolic acid) grafted hyaluronic acid (HA-PLGA) was successfully developed for periodontal barrier applications. HA was chemically modified with adipic acid dihydrazide (ADH) in the mixed solvent of water and ethanol, which resulted in a high degree of HA modification up to 85 mol.%. The stability of HA-ADH to enzymatic degradation by hyaluronidase increased with ADH content in HA-ADH. When the ADH content in HA-ADH was higher than 80 mol.%, HA-ADH became soluble in dimethyl sulfoxide and could be grafted to the activated PLGA with N,N'-dicyclohexyl carbodiimide and N-hydroxysuccinimide. The resulting HA-PLGA was used for the preparation of biphasic periodontal barrier membranes in chloroform. According to in vitro hydrolytic degradation tests in phosphate buffered saline, HA-PLGA/PLGA blend film with a weight ratio of 1/2 degraded relatively slowly compared to PLGA film and HA coated PLGA film. Four different samples of a control, OSSIX(TM) membrane, PLGA film, and HA-PLGA/PLGA film were assessed as periodontal barrier membranes for the calvarial critical size bone defects in SD rats. Histological and histomorphometric analyses revealed that HA-PLGA/PLGA film resulted in the most effective bone regeneration compared to other samples with a regenerated bone area of 63.1% covering the bone defect area.