Journal of Prosthodontics-Implant Esthetic and Reconstructive Dentistry最新文献

{"title":"Effect of finishing and polishing techniques on the fit accuracy and dimensions of conventional and CAD-CAM removable partial denture frameworks.","authors":"Majed S Altoman, Pooya Soltanzadeh, Montry S Suprono, Thrya S Gadah, Mathew T Kattadiyil","doi":"10.1111/jopr.13950","DOIUrl":"https://doi.org/10.1111/jopr.13950","url":null,"abstract":"<p><strong>Purpose: </strong>The purpose of this study was to compare the effects of finishing and polishing techniques on the fit accuracy, metal loss, and surface roughness of conventional versus CAD-CAM removable partial denture (RPD) frameworks.</p><p><strong>Materials and methods: </strong>A 3D-printed maxillary Kennedy class III modification I model served as the master cast. Forty impressions (20 conventional and 20 digital) were divided into four groups: lost-wax technique (Group I: LWT), CAD-printed (Group II: CAD-RP), CAD-printed from a stone cast (Group III: CAD-RPS), and lost-wax technique from resin-printed models (Group IV: LWTR). Various finishing and polishing techniques were applied, followed by digital scanning for fit accuracy assessment using surface matching software. Metal thickness loss and surface roughness were evaluated pre- and post-finishing and polishing. The Kruskal-Wallis test followed by the Scheffe post-hoc test were conducted to evaluate the fit accuracy between groups (α = 0.05).</p><p><strong>Results: </strong>Color mapping revealed significant differences (p < 0.001) between conventionally casted RPD frameworks and 3D-printed groups post-finishing and polishing. The most significant gap was observed with the guide plates from printed RPD frameworks. The D-Lyte technique resulted in less metal loss compared to the conventional finishing and polishing technique (p < 0.001).</p><p><strong>Conclusion: </strong>Within the limitations of this study, conventionally processed RPD groups exhibited better overall fit accuracy post-finishing and polishing. Both conventional cast and 3D-printed RPD frameworks showed clinically acceptable fit accuracy. The D-Lyte technique presented less metal loss and smoother surfaces compared to other groups, suggesting it as a viable alternative.</p>","PeriodicalId":49152,"journal":{"name":"Journal of Prosthodontics-Implant Esthetic and Reconstructive Dentistry","volume":null,"pages":null},"PeriodicalIF":3.4,"publicationDate":"2024-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142299355","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Comparative evaluation of the effects of laser and chemical denture disinfectants on the surface characteristics of CAD-CAM and conventional denture resins: An in vitro experimental study.","authors":"Rania Moussa, Passent Ellakany, Shaimaa M Fouda, Mai Salah El-Din","doi":"10.1111/jopr.13952","DOIUrl":"https://doi.org/10.1111/jopr.13952","url":null,"abstract":"<p><strong>Purpose: </strong>The purpose of this study was to assess the effect of Ga-Al-Ar diode, Nd:YAG lasers, and chemical disinfectants (NaOCl, vinegar, and Corega) on surface roughness (Ra) and hardness (VHN) of polymethylmethacrylate (PMMA), thermoplastic polyamide, milled and 3D-printed denture base resins.</p><p><strong>Materials and methods: </strong>About 432 specimens of PMMA, thermoplastic polyamide, milled, and 3D-printed resins were divided into six subgroups (n = 18): distilled water (control:C), Ga-Al-Ar diode laser (L1), Nd:YAG laser (L2), 1% sodium hypochlorite (NaOCl), vinegar (AA), and Corega (CR). Each specimen's Ra and VHN were measured. Surface topography assessment was done using scanning electron microscopy (SEM). Analysis was done using ANOVA and post hoc Tukey's test (p = 0.05).</p><p><strong>Results: </strong>A significant difference was noted in Ra and VHN as affected by denture base materials, surface disinfectants, and their interaction (p < 0.001). Results showed a significant increase in Ra of PMMA with NaOCL (p < 0.001), AA (p = 0.005), and CR (p = 0.009), thermoplastic polyamide with L1 (p = 0.012), L2 (p = 0.015), NaOCL AA, and CR (p < 0.001 each), milled resin with AA NaOCL, and CR (p < 0.001 each), and 3D-printed resin with L1, NaOCl, AA (p < 0.001 each), and CR (p = 0.008). The VHN increased in PMMA with NaOCL (p < 0.001), AA (p = 0.044), and CR (p < 0.001), thermoplastic polyamide with L1 (p = 0.037), milled resin with L1, L2, and CR (p < 0.001 each), and 3D-printed resin with L1, NaOCl (p < 0.001 each), and decreased with CR (p = 0.007).</p><p><strong>Conclusion: </strong>The tested properties showed variations affected by denture base material and surface disinfectants. Laser treatments induced smoother surfaces than chemical disinfectants. Laser improved the surface hardness of CAD-CAM resins, while chemical immersion improved that of PMMA.</p>","PeriodicalId":49152,"journal":{"name":"Journal of Prosthodontics-Implant Esthetic and Reconstructive Dentistry","volume":null,"pages":null},"PeriodicalIF":3.4,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142299328","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Comparison of full-arch mandibular reconstruction with dental implants using completely splinted or segmentally splinted prostheses with two different occlusal schemes: A finite-element analysis.","authors":"Sarah Abrishamkar, Amirhossein Fathi, Mahsa Ghorbani, Ramin Mosharraf","doi":"10.1111/jopr.13954","DOIUrl":"https://doi.org/10.1111/jopr.13954","url":null,"abstract":"<p><strong>Purpose: </strong>This study aimed to comparatively analyze full-arch mandibular reconstruction using dental implants. It focused on two distinct prosthesis configurations: completely splinted and segmentally splinted. These configurations were evaluated under two different occlusal schemes-group function and canine guidance-utilizing finite element analysis (FEA).</p><p><strong>Materials and methods: </strong>The methodology involved developing three-dimensional finite element models from computed tomography data acquired from an edentulous patient. Six dental implants were utilized to complete the mandibular reconstruction. Prosthetic reconstruction was conducted with completely and segmentally splinted prostheses, each employing group function and canine guidance occlusal schemes. Consequently, four distinct models were analyzed. Following meshing, a 200 N load was applied at a 30-degree angle. Subsequent evaluation encompassed stress, strain distribution, and the overall deformation of the implants, crowns, and underlying bone structure assessment.</p><p><strong>Results: </strong>The group function occlusal scheme generally exhibited lower stress values than the canine guidance occlusal scheme, with three-piece prostheses demonstrating even lower stress levels than one-piece prostheses. Conversely, the canine guidance occlusal scheme exhibited higher stress values overall.</p><p><strong>Conclusion: </strong>The findings of this study may assist clinicians in selecting the most effective occlusal scheme and prosthetic configuration for implant-supported mandibular restorations, potentially enhancing treatment outcomes and reducing the risk of mechanical complications. In summary, results indicated that group function loading, irrespective of prosthesis type, offers more uniform load distribution and lower stress values, making it a preferable choice over canine guidance. Within the group function occlusal scheme, three-piece prostheses demonstrated lower stress values than one-piece prostheses, but the clinical significance of this difference appears to be minimal.</p>","PeriodicalId":49152,"journal":{"name":"Journal of Prosthodontics-Implant Esthetic and Reconstructive Dentistry","volume":null,"pages":null},"PeriodicalIF":3.4,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142299329","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effects of post‐curing light intensity on the trueness, compressive strength, and resin polymerization characteristics of 3D‐printed 3‐unit fixed dental prostheses","authors":"Citra Dewi Sahrir, Wei‐Shao Lin, Chin‐Wei Wang, Wei‐Chun Lin","doi":"10.1111/jopr.13951","DOIUrl":"https://doi.org/10.1111/jopr.13951","url":null,"abstract":"PurposeTo investigate the effect of different post‐curing light intensities on the trueness, compressive strength, and resin polymerization of 3D‐printed 3‐unit fixed dental prostheses (FPD).Materials and MethodsA total of 60 specimens were prepared to support a 3‐unit FDP with a deep chamfer marginal design, utilizing computer‐aided design and computer‐aided manufacturing (CAD‐CAM) technology. Light‐polymerizing FDP resin with varying light intensities (105, 210, 420, and 840 mW/cm<jats:sup>2</jats:sup>) was employed for 10 min. Subsequently, trueness assessment, fracture load testing, scanning electron microscopy (SEM) surface examination, and Fourier‐Transform Infrared (FTIR) analysis were conducted. A one‐way analysis of variance (ANOVA) was performed to ascertain the differences between the experimental groups (<jats:italic>p</jats:italic> &lt; 0.05).ResultsThe group exposed to 210 mW/cm<jats:sup>2</jats:sup> showed the highest trueness (57.6 ± 2.1 µm), while the 840 mW/cm<jats:sup>2</jats:sup> group had the highest deviation (79.3 ± 2.7 µm) (<jats:italic>p</jats:italic> &lt; 0.001). Significant differences in fracture resistance were found between groups (<jats:italic>p</jats:italic> &lt; 0.001), with mean fracture strengths of 1149.77 ± 67.81 N, 1264.92 ± 39.06 N, 1331.34 ± 53.62 N, and 1439.93 ± 34.58 N for light intensities of 105, 210, 420, and 840 mW/cm<jats:sup>2</jats:sup>, respectively (<jats:italic>p</jats:italic> &lt; 0.001). The resin polymerization analysis shows a peak intensity surge at 3579 cm<jats:sup>−1</jats:sup> for O‐H and C‐H stretching vibrations, except in samples exposed to 105 mw/cm<jats:sup>2</jats:sup> light, with the lowest peak at 2890 cm<jats:sup>−1</jats:sup>. The performance of resin polymerization is most significant under the condition of 840 mW/cm<jats:sup>2</jats:sup>.ConclusionThe light intensity of 210 mW/cm<jats:sup>2</jats:sup> exhibited the highest trueness, while the 840 mW/cm<jats:sup>2</jats:sup> group showed the highest deviation. However, the light intensity of 840 mW/cm<jats:sup>2</jats:sup> demonstrated the highest compressive strength. Furthermore, polymerization occurred at all post‐treatment light intensities except 105 mW/cm<jats:sup>2</jats:sup>. These findings indicate that while low‐intensity usage offers greater trueness, high‐intensity usage provides better compressive strength and polymerization. Therefore, 210 mW/cm<jats:sup>2</jats:sup> could be the recommended solution for post‐curing.","PeriodicalId":49152,"journal":{"name":"Journal of Prosthodontics-Implant Esthetic and Reconstructive Dentistry","volume":null,"pages":null},"PeriodicalIF":4.0,"publicationDate":"2024-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142248335","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Vertical marginal gap and internal fit of virgilite-based lithium disilicate glass ceramic veneers with different preparation designs.","authors":"Amr Rizk, Ahmed Abdou, Amira Mohammad Samy, Nouran Mahmoud, Sarah Omar","doi":"10.1111/jopr.13937","DOIUrl":"https://doi.org/10.1111/jopr.13937","url":null,"abstract":"<p><strong>Purpose: </strong>To evaluate and compare internal fit and marginal adaptation of conventional lithium disilicate (LDS) glass ceramics and LDS containing virgilite computer-aided design and manufacturing (CAD-CAM) blocks before and after aging.</p><p><strong>Materials and methods: </strong>Seventy-two epoxy replicated dies from two prepared maxillary right central incisors acrylic typodont were divided into two groups of different preparation designs (n = 36): Group I, incisal butt-joint, and Group P, incisal overlap. Each group was further subdivided into two equal groups according to ceramic material (n = 18): Group E, IPS e.max CAD, and Group T, Tessera advanced lithium disilicate (ALD) CAD-CAM blocks. The replica technique was used to assess the internal fit using a stereomicroscope at 45× magnification. Laminate veneers were cemented to their corresponding epoxy dies, then the vertical marginal gap was evaluated before and after thermal cycling. Repeated measures analysis of variance (ANOVA) were used for marginal fit data and 2-way ANOVA for internal fit measurements (α = 0.05).</p><p><strong>Results: </strong>For internal fit, there were no significant differences between tested groups. For vertical marginal gap results, two-way ANOVA showed that only aging had a significant effect on the vertical marginal gap (p < 0.001), while different CAD-CAM materials and preparation designs did not affect the vertical marginal gap.</p><p><strong>Conclusions: </strong>The vertical marginal gap and internal fits of IPS e.max CAD and CEREC Tessera CAD for both preparation designs were comparable. Aging significantly affected the vertical marginal gap of the laminate veneers of both materials and both preparation designs; however, all were within clinically acceptable ranges before and after aging.</p>","PeriodicalId":49152,"journal":{"name":"Journal of Prosthodontics-Implant Esthetic and Reconstructive Dentistry","volume":null,"pages":null},"PeriodicalIF":3.4,"publicationDate":"2024-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142156454","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effect of cleaning solution on surface properties of 3D-printed denture materials.","authors":"Marina Rodrigues Santi, Nadima Khodor, Michael Sekula, David Donatelli, Grace Mendonça De Souza","doi":"10.1111/jopr.13936","DOIUrl":"https://doi.org/10.1111/jopr.13936","url":null,"abstract":"<p><strong>Purpose: </strong>To evaluate the effect of cleaning solutions on surface properties of 3D-printed resins.</p><p><strong>Materials and methods: </strong>Seven different resin materials for denture base and teeth were used in the form of 280 half-disks. Samples were randomly assigned to two cleaning groups (FD, FreshDent; PO, Polydent), with daily 2- or 3-min immersion followed by water storage, repeated for 30 days. Samples were then cleaned in an ultrasonic bath with water and analyzed for surface roughness (Keyence, VHX-7000N) and hardness (Shimadzu, HMV-2 series). The pH of cleaning solutions was analyzed over 5-min and the surface morphology of specimens was analyzed via scanning electron microscopy (SEM). Statistical analysis used two-way ANOVA (α = 0.05).</p><p><strong>Results: </strong>Surface roughness of base materials was significantly affected (p < 0.001), whereas roughness of teeth materials was not. As for hardness, there was a significant interaction between materials and cleaning solution for both, base (p < 0.001) and teeth (p < 0.001). For teeth materials, PO significantly increased Denture's (Dentca) hardness and decreased that of Rodin's (Pac Dent), while PO significantly increased Rodin's Base (Pac Dent) hardness. The hardness of Flexcera Ultra (Envision Tec), Glidewell (Glidewell), Lucitone (Dentsply Sirona), and NextDent (NextDent) teeth and base materials were not affected by the cleaning solution. Overall, the pH of FD averaged 7.3 and PO averaged 6.6. All the SEM images indicated surface irregularities after immersion in either FD or PO.</p><p><strong>Conclusions: </strong>One-month of storage and cyclic cleaning of 3D- printed resins did not affect surface roughness but had a significant impact on hardness. The cleaning solutions' effect was not homogeneous among materials.</p>","PeriodicalId":49152,"journal":{"name":"Journal of Prosthodontics-Implant Esthetic and Reconstructive Dentistry","volume":null,"pages":null},"PeriodicalIF":3.4,"publicationDate":"2024-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142134204","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Influence of CAD-CAM manufacturing methods on the accuracy and mechanical properties of implant-supported prostheses: A systematic review.","authors":"Passent Ellakany, Marwa Madi, Amira H Elwan, Turki Alshehri, Hussain Aljubran, Nourhan M Aly","doi":"10.1111/jopr.13933","DOIUrl":"https://doi.org/10.1111/jopr.13933","url":null,"abstract":"<p><strong>Purpose: </strong>This systematic review aimed to provide comprehensive insights on the accuracy, fit, and mechanical characteristics of implant-supported computer-aided design and computer-aided manufacturing (CAD-CAM) prostheses, with a focus on milled and 3D-printed approaches.</p><p><strong>Methods: </strong>The research question focused on implant-supported dental prostheses, comparing different manufacturing techniques (conventional, milled, and 3D-printed) to determine the different factors affecting the mechanical properties and fit of the CAD-CAM implant-supported prosthesis. The eligibility criteria encompassed studies involving implant-supported restorations, clear reporting of manufacturing techniques, and English-language publications from the last decade. The search was conducted across three main databases, MEDLINE, Scopus, and Web of Science in September 2023. Publication details, study characteristics, and methodological details of each included study were described.</p><p><strong>Results: </strong>Of the initial 1964 articles, 581 met the inclusion criteria, and 104 studies were included in the final qualitative analysis. The majority of studies were conducted in the United States, Turkey, and Brazil. Fourteen studies evaluated accuracy parameters, while four studies focused on mechanical characteristics. The studies revealed variability in mechanical properties and marginal and internal fit, with fabrication methods impacting the structural integrity and stress distribution of the prostheses.</p><p><strong>Conclusions: </strong>The findings suggest that digital manufacturing workflows, both milling and 3D printing, yield acceptable properties for implant-supported restorations with minimal variations in fit and accuracy. Notably, 3D printing and hybrid techniques demonstrate advantages in specific aspects like marginal fit and stress distribution. However, the milled prosthesis provided superior results in flexural strength and fracture resistance compared to conventional methods. Further research is needed to confirm these findings in clinical settings.</p>","PeriodicalId":49152,"journal":{"name":"Journal of Prosthodontics-Implant Esthetic and Reconstructive Dentistry","volume":null,"pages":null},"PeriodicalIF":3.4,"publicationDate":"2024-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142134205","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Microstructural and flexural strength of various CAD-CAM lithium disilicate ceramics.","authors":"Joissi Ferrari Zaniboni, Amanda Soares Silva, Aryvelto Miranda Silva, João Felipe Besegato, Oscar Fernando Muñoz-Chávez, Edson Alves de Campos","doi":"10.1111/jopr.13938","DOIUrl":"https://doi.org/10.1111/jopr.13938","url":null,"abstract":"<p><strong>Purpose: </strong>To analyze the microstructural and mechanical properties of various commercial trademarks of lithium disilicate ceramics for CAD-CAM systems.</p><p><strong>Materials and methods: </strong>Specimens of different lithium disilicate ceramics were obtained and randomized into 5 groups (n = 14): EM: e.max CAD; RT: Rosetta SM; EV: Evolith; PM: Smile-Lithium CAD; and, HS: HaHaSmile. The microstructural analysis was performed by X-ray diffraction (XRD) and scanning electron microscopy (SEM); for flexural strength, the three-point bending flexure test was used. XRD and SEM data were qualitatively evaluated. Data from flexural strength were assessed with one-way ANOVA test (α = 0.05) and Weibull analysis.</p><p><strong>Results: </strong>High peaks corresponding to the lithium metasilicate and lithium disilicate pattern with similar intensities were observed in all ceramics in the XRD analysis. SEM images showed similar patterns of crystalline structure in the EM and RT ceramics, while the other three groups presented different crystal morphologies than the previous ones and were similar to each other. No differences were found in flexural strength among the groups (p = 0.28).</p><p><strong>Conclusions: </strong>The CAD-CAM lithium disilicate ceramics showed comparable crystalline intensities. The microstructure of the EM and RT ceramics were different from the other groups. Flexural strength was similar among all ceramics.</p>","PeriodicalId":49152,"journal":{"name":"Journal of Prosthodontics-Implant Esthetic and Reconstructive Dentistry","volume":null,"pages":null},"PeriodicalIF":3.4,"publicationDate":"2024-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142134206","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effect of artificial aging on fracture toughness and hardness of 3D-printed and milled 3Y-TZP zirconia.","authors":"Abdulaziz Alhotan, Burak Yilmaz, Anna Weber, Rua Babaier, Christoph Bourauel, Ahmed Mahmoud Fouda","doi":"10.1111/jopr.13943","DOIUrl":"https://doi.org/10.1111/jopr.13943","url":null,"abstract":"<p><strong>Purpose: </strong>This study aimed to evaluate the impact of artificial aging on the fracture toughness and hardness of three-dimensional (3D)-printed and computer-aided design and computer-aided manufacturing (CAD-CAM) milled 3 mol% yttria-stabilized tetragonal zirconia polycrystals (3Y-TZP).</p><p><strong>Materials and methods: </strong>Forty bar-shaped specimens (45 × 4 × 3 mm) were prepared using two manufacturing technologies: 3D printing (LithaCon 3Y 210, Lithoz GmbH, Vienna, Austria; n = 20) and milling (Initial Zirconia ST, GC, Japan; n = 20) of 3Y-TZP. The chevron-notch beam method was used to assess the fracture toughness according to ISO 24370. Specimens from each 3Y-TZP group were divided into two subgroups (n = 10) based on the artificial aging process (autoclaving): nonaged and aged. Nonaged specimens were stored at room temperature, while aged specimens underwent autoclave aging at 134°C under 2 bar-pressure for 5 h. Subsequently, the specimens were immersed in absolute 99% ethanol using an ultrasonic cleaner for 5 min. Each specimen was preloaded by subjecting it to a 4-point loading test, with a force of up to 200 N applied for three cycles. Further 4-point loading was conducted at a rate of 0.5 mm/min under controlled temperature and humidity conditions until fracture occurred. The maximum force (F_max) was recorded and the chevron notch was examined at 30 × magnification under an optical microscope for measurements before the fracture toughness (K_Ic) was calculated. Microhardness testing was also performed to measure the Vickers hardness number (VHN). A scanning electron microscope (SEM) coupled with an energy dispersive X-ray unit (EDX) was used to examine surface topography and chemical composition. X-ray diffraction (XRD) was conducted to identify crystalline structure. Data were statistically analyzed using two-way ANOVA and Student's t-test with a significance level of 0.05.</p><p><strong>Results: </strong>The nonaged 3D-printed 3Y-TZP group exhibited a significantly higher fracture toughness value (6.07 MPa m^1/2) than the milled 3Y-TZP groups (p < 0.001). After autoclave aging, the 3D-printed 3Y-TZP group maintained significantly higher fracture toughness (p < 0.001) compared to the milled 3Y-TZP group. However, no significant differences in hardness values (p = 0.096) were observed between the aged and nonaged groups within each manufacturing process (3D-printed and milled) independently.</p><p><strong>Conclusion: </strong>The findings revealed that the new 3D-printed 3Y-TZP produced by the lithography-based ceramic manufacturing (LCM) technology exhibited superior fracture toughness after autoclave aging compared to the milled 3Y-TZP. While no significant differences in hardness were observed between the aged groups, the 3D-printed material demonstrated greater resistance to fracture, indicating enhanced mechanical stability.</p>","PeriodicalId":49152,"journal":{"name":"Journal of Prosthodontics-Implant Esthetic and Reconstructive Dentistry","volume":null,"pages":null},"PeriodicalIF":3.4,"publicationDate":"2024-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142127125","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Comparison of stress distribution around splinted and nonsplinted implants with different crown height space in posterior mandible: A finite element analysis study.","authors":"Hamiyet Güngör Erdoğan, Mert Keleş, Burak Yılmaz","doi":"10.1111/jopr.13935","DOIUrl":"https://doi.org/10.1111/jopr.13935","url":null,"abstract":"<p><strong>Purpose: </strong>The purpose of this finite element analysis (FEA) study was to analyze the stress distribution on prosthetic components of splinted and nonsplinted prostheses, bone, and implants with different crown height space (CHS).</p><p><strong>Materials and methods: </strong>Mandibular posterior segment was modeled with no resorption at the second premolar site and various amounts of resorption (0, 3, 6, and 9 mm) at the first molar site. Two adjacent implants (Straumann bone level implants, 4.1 mm×8 mm) were placed; at the second premolar site, the crown height was 8 mm and at the first molar site, the crown height varied (8, 11, 14, and 17 mm), depending on the amount of resorption. Both splinted and nonsplinted crowns were designed. Vertical and oblique loads of 400 N were applied to the crowns. von Mises stress was used to evaluate the stress distribution in the implant complex and maximum principal stress was used to evaluate the stress in the bone.</p><p><strong>Results: </strong>When oblique forces were applied, the highest von Mises stresses were observed for nonsplinted crowns in the 17 mm CHS group. The maximum principal and minimum principal stresses observed in bone under oblique loading increased with increased CHS for nonsplinted restorations.</p><p><strong>Conclusions: </strong>Crown height affected the amount of stress in bone and implant components. When the crown height difference between two adjacent implants increases, splinting may be crucial.</p>","PeriodicalId":49152,"journal":{"name":"Journal of Prosthodontics-Implant Esthetic and Reconstructive Dentistry","volume":null,"pages":null},"PeriodicalIF":3.4,"publicationDate":"2024-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142127124","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}