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Mancuso E, Mazzitelli C, Maravic T, Pitta J, Mengozzi A, Comba A, Baldi A, Scotti N, Mazzoni A, Fehmer V, Sailer I, Breschi L. The influence of finishing lines and margin location on enamel and dentin removal for indirect partial restorations: A micro-CT quantitative evaluation. J Dent 2022; 127:104334. [PMID: 36257512 DOI: 10.1016/j.jdent.2022.104334] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Revised: 10/11/2022] [Accepted: 10/14/2022] [Indexed: 11/21/2022] Open
Abstract
OBJECTIVES This in vitro research aimed to quantitatively evaluate the enamel and dentin tissue removal and the residual adhesion surface area (RAS) after different margin designs and locations for indirect partial restorations (IPR). METHODS A human molar was scanned using a Micro-CT and the STL file obtained was used to 3D-print 50 resin-tooth replicas. IPR standardized preparations were performed. The specimens were randomly assigned to 5 groups (n = 10), according to preparation and margin location to the dental equator (DE): 1) Rounded shoulder above the DE (SA); 2) Hollow chamfer above the DE (CA); 3) Butt joint above the DE (BJ); 4) Rounded shoulder below the DE (SB); 5) Chamfer below the DE (CB). Then, the tooth replicas were scanned and each STL file was aligned and superimposed to the original STL model file. Data of enamel and dentin volume removal and RAS were assessed and statistically analyzed (one-way ANOVA and Kruskal-Wallis tests for the two dental substrates respectively). Significance was set at p<0.05. RESULTS Differences in dental tissue reductions were related to the margin location. Above the equator, SA, CA, and BJ performed comparably (p>0.05). Below the equator, CB was significantly more conservative in enamel reduction than SB (p<0.05) and showed the highest enamel adhesive surface exposure among the tested preparations (p<0.05). CONCLUSIONS When the preparation margin is placed above DE, BJ determines a greater exposure of dentin, reducing the adhesive surface in enamel. Below DE, SB seems to be more aggressive in terms of tissue removal compared to CB. CLINICAL SIGNIFICANCE The results of this in vitro study suggest that in teeth requiring partial restoration with the margin below the dental equator, a chamfer preparation would be more conservative than a shoulder preparation. When above the equator, preparations with flat designs would expose more dentine providing a worse substrate for adhesion.
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Affiliation(s)
- Edoardo Mancuso
- Department of Biomedical and Neuromotor Science (DIBINEM), Alma Mater University of Bologna, via S. Vitale 59, 40125 Bologna, Italy
| | - Claudia Mazzitelli
- Department of Biomedical and Neuromotor Science (DIBINEM), Alma Mater University of Bologna, via S. Vitale 59, 40125 Bologna, Italy
| | - Tatjana Maravic
- Department of Biomedical and Neuromotor Science (DIBINEM), Alma Mater University of Bologna, via S. Vitale 59, 40125 Bologna, Italy
| | - João Pitta
- Division of Fixed Prosthodontics and Biomaterials, University Clinics for Dental Medicine, University of Geneva, Geneva, Switzerland
| | - Alessandro Mengozzi
- Department of Biomedical and Neuromotor Science (DIBINEM), Alma Mater University of Bologna, via S. Vitale 59, 40125 Bologna, Italy
| | - Allegra Comba
- Department of Surgical Sciences, Dental School Lingotto, University of Turin, Via Nizza 230, 10126 Turin, Italy
| | - Andrea Baldi
- Department of Surgical Sciences, Dental School Lingotto, University of Turin, Via Nizza 230, 10126 Turin, Italy
| | - Nicola Scotti
- Department of Surgical Sciences, Dental School Lingotto, University of Turin, Via Nizza 230, 10126 Turin, Italy
| | - Annalisa Mazzoni
- Department of Biomedical and Neuromotor Science (DIBINEM), Alma Mater University of Bologna, via S. Vitale 59, 40125 Bologna, Italy
| | - Vincent Fehmer
- Division of Fixed Prosthodontics and Biomaterials, University Clinics for Dental Medicine, University of Geneva, Geneva, Switzerland
| | - Irena Sailer
- Division of Fixed Prosthodontics and Biomaterials, University Clinics for Dental Medicine, University of Geneva, Geneva, Switzerland
| | - Lorenzo Breschi
- Department of Biomedical and Neuromotor Science (DIBINEM), Alma Mater University of Bologna, via S. Vitale 59, 40125 Bologna, Italy.
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Restoring Teeth with an Advanced Lithium Disilicate Ceramic: A Case Report and 1-Year Follow-Up. Case Rep Dent 2022; 2022:6872542. [PMID: 36157203 PMCID: PMC9507783 DOI: 10.1155/2022/6872542] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Revised: 07/15/2022] [Accepted: 07/22/2022] [Indexed: 11/17/2022] Open
Abstract
Advancements in materials science and bonding protocols as well as new manufacturing methods foster the development of novel ceramic materials to meet the increased demands for highly aesthetic, biocompatible, and long-lasting restorations in fixed prosthodontics. This case report highlights the minimally invasive rehabilitation with a new advanced lithium disilicate (ALD) ceramic block. It is reinforced with virgilite crystals in managing esthetic demand of patient besides having a high flexural strength. According to the manufacturer, the material provides a biaxial strength measured at >700 MPa and improved optical properties. The remarkable speed sintering time of approx. 4.5 minutes makes processing very fast. Time efficiency, predictability, and economically interesting treatment options are of great importance in current dentistry and can be well implemented in CAD/CAM dentistry. The newly introduced ALD ceramic for the “Chairside Economical Restoration of Esthetic Ceramics”/“CEramic REConstruction” (CEREC) system produces an esthetically pleasing and clinically excellent restoration. The shorter processing time combined with high flexural strength will optimize the chairside workflow. New treatment indication options for lithium disilicate ceramics will expand. Although more evidence from long-term clinical studies is needed to verify the clinical performance and manufacturer recommendations regarding indication, preparation and cementation must be followed very strictly. In the present case report, restorations were indicated for seven posterior teeth, which were prepared, scanned, designed with CEREC-Primescan SW 5.1.3, and fabricated with MCX5. The monolithic restorations were placed adhesively. The rehabilitation with the ALD blocks resulted in an aesthetically pleasing, functional outcome that improved overall treatment time and increased patient and practitioner satisfaction, which remained stable over a one-year follow-up period.
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Seidel A, Belli R, Breidebach N, Wichmann M, Matta RE. The occlusal wear of ceramic fixed dental prostheses: 3-Year results in a randomized controlled clinical trial with split-mouth design. J Dent 2020; 103:103500. [DOI: 10.1016/j.jdent.2020.103500] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Revised: 09/23/2020] [Accepted: 10/10/2020] [Indexed: 10/23/2022] Open
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Falahchai M, Babaee Hemmati Y, Neshandar Asli H, Neshandar Asli M. Marginal adaptation of zirconia‐reinforced lithium silicate overlays with different preparation designs. J ESTHET RESTOR DENT 2020; 32:823-830. [DOI: 10.1111/jerd.12642] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Revised: 07/21/2020] [Accepted: 07/30/2020] [Indexed: 12/01/2022]
Affiliation(s)
- Mehran Falahchai
- Dental Sciences Research Center, Department of Prosthodontics School of Dentistry, Guilan University of Medical Sciences Rasht Iran
| | - Yasamin Babaee Hemmati
- Dental Sciences Research Center, Department of Orthodontics School of Dentistry, Guilan University of Medical Sciences Rasht Iran
| | - Hamid Neshandar Asli
- Dental Sciences Research Center, Department of Prosthodontics School of Dentistry, Guilan University of Medical Sciences Rasht Iran
| | - Marzieh Neshandar Asli
- Undergraduate student, Dental School Anzali Campus, Guilan University of Medical Sciences Rasht Iran
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Falahchai M, Babaee Hemmati Y, Neshandar Asli H, Rezaei E. Effect of Tooth Preparation Design on Fracture Resistance of Zirconia‐Reinforced Lithium Silicate Overlays. J Prosthodont 2020; 29:617-622. [DOI: 10.1111/jopr.13160] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/05/2020] [Indexed: 11/28/2022] Open
Affiliation(s)
- Mehran Falahchai
- Dental Sciences Research Center, Department of Prosthodontics, School of DentistryGuilan University of Medical Sciences Rasht Iran
| | - Yasamin Babaee Hemmati
- Dental Sciences Research Center, Department of Orthodontics, School of DentistryGuilan University of Medical Sciences Rasht Iran
| | - Hamid Neshandar Asli
- Dental Sciences Research Center, Department of Prosthodontics, School of DentistryGuilan University of Medical Sciences Rasht Iran
| | - Elnaz Rezaei
- Dental Sciences Research Center, Department of Prosthodontics, School of DentistryGuilan University of Medical Sciences Rasht Iran
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Influence of bonding surface and bonding methods on the fracture resistance and survival rate of full-coverage occlusal veneers made from lithium disilicate ceramic after cyclic loading. Dent Mater 2019; 35:1351-1359. [PMID: 31351579 DOI: 10.1016/j.dental.2019.07.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2018] [Revised: 05/27/2019] [Accepted: 07/01/2019] [Indexed: 11/23/2022]
Abstract
OBJECTIVES The purpose of this laboratory study was to evaluate the influence of bonding method and type of dental bonding surface on fracture resistance and survival rate of resin bonded occlusal veneers made from lithium disilicate ceramic after cyclic loading. METHODS Fourty-eight extracted molars were divided into three groups (N=16) depending on the preparation: within enamel, within dentin/enamel or within enamel/composite resin filling. Lithium disilicate occlussal veneers were fabricated with a fissure-cusp thickness of 0.3-0.6mm. Restorations were etched (5% HF), silanated and adhesively luted using a dual-curing luting composite resin. Test groups were divided into two subgroups, one using a only a self-etching primer, the other additionally etching the enamel with phosphoric acid. After water storage (37°C; 21d) and thermocycling (7500 cycles; 5-55°C), specimens were subjected to dynamic loading in a chewing simulator (600,000 cycles; 10kg/2Hz). Surviving specimens were loaded until fracture using a universal testing machine. RESULTS All specimens survived artificial aging, several specimens showed some damage. ANOVA revealed that enamel etching provided statistically significantly (p≤0.05) higher fracture resistance than self-etching when bonding to enamel and dentin. Self-etching provided statistically significant (p≤0.05) higher fracture resistance for the enamel-composite group than for the enamel group. Enamel etching provided statistically significant (p≤0.05) higher fracture resistance for the enamel and dentin group than for groups enamel and enamel-composite. SIGNIFICANCE Etching enamel improved the fracture resistance of occlusal veneers when bonding to dentin and enamel and increased the survival rate when bonding to enamel.
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Helal MA, Wang Z. Biomechanical Assessment of Restored Mandibular Molar by Endocrown in Comparison to a Glass Fiber Post‐Retained Conventional Crown: 3D Finite Element Analysis. J Prosthodont 2017; 28:988-996. [PMID: 29067737 DOI: 10.1111/jopr.12690] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/02/2017] [Indexed: 11/27/2022] Open
Affiliation(s)
- Mohammed Abu Helal
- Prosthodontic Department, Henan Provincial People's HospitalPeople's Hospital of Zhengzhou University Zhengzhou China
| | - Zhigang Wang
- Prosthodontic Department, Henan Provincial People's HospitalPeople's Hospital of Zhengzhou University Zhengzhou China
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Sasse M, Krummel A, Klosa K, Kern M. Influence of restoration thickness and dental bonding surface on the fracture resistance of full-coverage occlusal veneers made from lithium disilicate ceramic. Dent Mater 2015; 31:907-15. [DOI: 10.1016/j.dental.2015.04.017] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2014] [Revised: 03/04/2015] [Accepted: 04/28/2015] [Indexed: 10/23/2022]
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SARIDAG S, SARI T, OZYESIL AG, ARI AYDINBELGE H. Fracture resistance of endodontically treated teeth restored with ceramic inlays and different base materials. Dent Mater J 2015; 34:175-80. [DOI: 10.4012/dmj.2014-069] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Affiliation(s)
- Serkan SARIDAG
- Department of Prosthodontics, Faculty of Dentistry, Kocaeli University
| | - Tugrul SARI
- Department of Prosthodontics, Faculty of Dentistry, Bezmialem Vakıf University
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Boitelle P, Mawussi B, Tapie L, Fromentin O. A systematic review of CAD/CAM fit restoration evaluations. J Oral Rehabil 2014; 41:853-74. [DOI: 10.1111/joor.12205] [Citation(s) in RCA: 138] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/29/2014] [Indexed: 11/27/2022]
Affiliation(s)
- P. Boitelle
- Prosthodontic Department; Faculty of Dentistry; University Lille Nord de France; Lille France
- Biomaterials and Interfaces Research Unit (URB2i - EA 4462); Faculty of Dentistry; Paris Descartes Sorbonne Paris Cité; Montrouge France
| | - B. Mawussi
- Biomaterials and Interfaces Research Unit (URB2i - EA 4462); Faculty of Dentistry; Paris Descartes Sorbonne Paris Cité; Montrouge France
- Faculty of Mechanical Engineering Paris 13 University; Sorbonne Paris Cité; Saint Denis France
| | - L. Tapie
- Biomaterials and Interfaces Research Unit (URB2i - EA 4462); Faculty of Dentistry; Paris Descartes Sorbonne Paris Cité; Montrouge France
- Faculty of Mechanical Engineering Paris 13 University; Sorbonne Paris Cité; Saint Denis France
| | - O. Fromentin
- Biomaterials and Interfaces Research Unit (URB2i - EA 4462); Faculty of Dentistry; Paris Descartes Sorbonne Paris Cité; Montrouge France
- Prosthodontic Department; Faculty of Dentistry; Paris Diderot; Sorbonne Paris Cité - Hospital Rothschild (AP-HP); Paris France
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3D-Finite element analysis of molars restored with endocrowns and posts during masticatory simulation. Dent Mater 2013; 29:e309-17. [DOI: 10.1016/j.dental.2013.09.014] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2013] [Revised: 07/03/2013] [Accepted: 09/25/2013] [Indexed: 11/18/2022]
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Saridag S, Sevimay M, Pekkan G. Fracture resistance of teeth restored with all-ceramic inlays and onlays: an in vitro study. Oper Dent 2013; 38:626-34. [PMID: 23391033 DOI: 10.2341/12-211-l] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Fracture resistance of inlays and onlays may be influenced by the quantity of the dental structure removed and the restorative materials used. The purpose of this in vitro study was to evaluate the effects of two different cavity preparation designs and all-ceramic restorative materials on the fracture resistance of the tooth-restoration complex. Fifty mandibular third molar teeth were randomly divided into the following five groups: group 1: intact teeth (control); group 2: inlay preparations, lithium-disilicate glass-ceramic (IPS e.max Press, Ivoclar Vivadent AG, Schaan, Liechtenstein); group 3: inlay preparations, zirconia ceramic (ICE Zirkon, Zirkonzahn SRL, Gais, Italy); group 4: onlay preparations, lithium-disilicate glass-ceramic (IPS e.max Press); and group 5: onlay preparations, zirconia ceramic (ICE Zirkon). The inlay and onlay restorations were adhesively cemented with dual polymerizing resin cement (Variolink II, Ivoclar Vivadent AG). After thermal cycling (5° to 55°C × 5000 cycles), specimens were subjected to a compressive load until fracture at a crosshead speed of 0.5 mm/min. Statistical analyses were performed using one-way analysis of variance and Tukey HSD tests. The fracture strength values were significantly higher in the inlay group (2646.7 ± 360.4) restored with lithium-disilicate glass-ceramic than those of the onlay group (1673.6 ± 677) restored with lithium-disilicate glass-ceramic. The fracture strength values of teeth restored with inlays using zirconia ceramic (2849 ± 328) and onlays with zirconia ceramic (2796.3 ± 337.3) were similar to those of the intact teeth (2905.3 ± 398.8). In the IPS e.max Press groups, as the preparation amount was increased (from inlay to onlay preparation), the fracture resistance was decreased. In the ICE Zirkon ceramic groups, the preparation type did not affect the fracture resistance results.
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Dejak B, Młotkowski A, Langot C. Three-dimensional finite element analysis of molars with thin-walled prosthetic crowns made of various materials. Dent Mater 2012; 28:433-41. [DOI: 10.1016/j.dental.2011.11.019] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2011] [Revised: 11/24/2011] [Accepted: 11/24/2011] [Indexed: 10/14/2022]
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Thompson MC, Thompson KM, Swain M. The all-ceramic, inlay supported fixed partial denture. Part 1. Ceramic inlay preparation design: a literature review. Aust Dent J 2010; 55:120-7; quiz 231. [DOI: 10.1111/j.1834-7819.2010.01214.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Guess PC, Strub JR, Steinhart N, Wolkewitz M, Stappert CF. All-ceramic partial coverage restorations—Midterm results of a 5-year prospective clinical splitmouth study. J Dent 2009; 37:627-37. [DOI: 10.1016/j.jdent.2009.04.006] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2009] [Revised: 04/12/2009] [Accepted: 04/19/2009] [Indexed: 10/20/2022] Open
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Stappert CF, Chitmongkolsuk S, Silva NR, Att W, Strub JR. Effect of mouth-motion fatigue and thermal cycling on the marginal accuracy of partial coverage restorations made of various dental materials. Dent Mater 2008; 24:1248-57. [DOI: 10.1016/j.dental.2008.02.005] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2007] [Revised: 02/05/2008] [Accepted: 02/08/2008] [Indexed: 10/22/2022]
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Soares CJ, Martins LRM, Fonseca RB, Correr-Sobrinho L, Fernandes Neto AJ. Influence of cavity preparation design on fracture resistance of posterior Leucite-reinforced ceramic restorations. J Prosthet Dent 2006; 95:421-9. [PMID: 16765154 DOI: 10.1016/j.prosdent.2006.03.022] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
STATEMENT OF PROBLEM Controversy exists concerning the preferred cavity design for posterior ceramic restorations to improve their resistance to fracture under occlusal load. PURPOSE The aim of this study was to assess the resistance to fracture of leucite-reinforced ceramic restorations placed on molars with different cavity preparation designs. MATERIAL AND METHODS Ninety noncarious molars were selected, stored in 0.2% thymol solution, and divided into 9 groups (n = 10): IT, intact teeth; CsI, conservative inlay; ExI, extensive inlay; CsO/mb, conservative onlay with mesio-buccal cusp coverage; ExO/mb, entensive onlay with mesio-buccal cusp coverage; CsO/b, conservative onlay with buccal cusp coverage; ExO/b, entensive onlay with buccal cusp coverage; CsO/t, conservative onlay with total cusp coverage; ExO/t, extensive onlay with total cusp coverage. Teeth were restored with a Leucite-reinforced ceramic (Cergogold). The fracture resistance (N) was assessed under compressive load in a universal testing machine. The data were analyzed with 1-way and 2-way analyses of variance, followed by the Tukey HSD test (alpha = .05). Fracture modes were recorded, based on the degree of tooth structure and restoration damage. RESULTS One-way analysis showed that intact teeth had the highest fracture resistance values. Two-way analyses showed no significant differences for the isthmus extention factor, but showed a significant difference for the preparation design type of fracture (P = .03), and also for the interaction between both factors (P = .013). The fracture mode observed in all groups tended to involve only restorations. CONCLUSION Within the limitations of this study, it was observed that cuspal coverage does not increase fracture resistance of the posterior tooth-restoration complex restored with leucite-reinforced ceramics.
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Affiliation(s)
- Carlos Jose Soares
- School of Dentistry, Federal University of Uberlandia, Minas Gerais, Brazil.
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Bitter K, Paris S, Hartwig C, Neumann K, Kielbassa AM. Shear Bond Strengths of Different Substrates Bonded to Lithium Disilicate Ceramics. Dent Mater J 2006; 25:493-502. [PMID: 17076319 DOI: 10.4012/dmj.25.493] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The aim of this study was to evaluate the shear bond strengths of pre- and untreated resin core materials to lithium disilicate ceramics. Bond strengths to dental hard tissues served as controls. Ceramic cubes (IPS-Empress II) were luted either with a one-step (Variolink II/Excite DSC) or multiple-step total etching bonding system (Tetric Flow/Syntac Classic) to ground surfaces of human enamel, dentin, and resin core materials (Clearfil Core, Multicore). Resin core materials were additionally pretreated with hydrofluoric acid (HF) or were silica-coated (CoJet System). Shear bond strengths were determined after 24-hour water storage (n=10) and thermocycling (TC) (n=10; 2000 cycles, 5-55 degrees C, 30 seconds). Bond strengths to enamel, dentin, and silica-coated composites were significantly higher compared to untreated and HF-pretreated composites (p<0.05; Tukey B). Indeed, silica coating of the composite resins significantly increased the bond strength to ceramics (p<0.05; Tukey B). Due to the lower bond strength values of ceramics to untreated composite resins (as compared to enamel and dentin), any indication for a resin core build-up prior to the preparation of a ceramic restoration should be considered carefully.
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Affiliation(s)
- Kerstin Bitter
- Department of Operative Dentistry and Periodontology, University School of Dental Medicine, Charité-Universitätsmedizin Berlin, Germany.
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Abstract
STATEMENT OF PROBLEM All-ceramic molar onlays continue to have higher failures from bulk fracture than similar cast metal onlays. PURPOSE The purpose of this retrospective study was to compare long-term failure rates and causes for posterior sintered feldspathic ceramic (Mirage) onlays placed with and without metal substructure reinforcement. MATERIAL AND METHODS Nineteen onlays were placed with and 78 without metal reinforcement in 50 older adolescent and adult patients treated by 2 prosthodontists in a private practice. All onlays opposed occluding tooth surfaces. Clinical judgment determined the type of onlay placed. Observational factors included patients, clinicians, onlay sites, and failure modes. Acrylic resin maxillary splints were generally provided for patients with multiple onlays or parafunctional habits. Thirty-six dies were also available for comparison of the occlusal thickness and taper of intact and failed molar onlays. The chi-square test or Fisher exact test, Student t test, and life table survival statistics were used to evaluate the data (alpha=.05). RESULTS Over 6 years, failures occurred in 21.1% of onlays placed with metal reinforcement and in 26.9% without metal reinforcement. Cumulative survival estimates (+/- standard error) were 62.4% +/- 14.7% and 60.5% +/- 6.3%, respectively (P=.84). Bulk fracture occurred in 16.5% of molars, independent of metal reinforcement (P=1.00). Overall, 11.4% of premolar and 33.9% of molar onlays failed. Irreversible pulpitis occurred in 6.2% of all teeth. From the dies, there were no clear relationships between either the thickness of occlusal ceramic material or the internal preparation taper and molar onlay failures, for onlays placed with or without metal reinforcement. CONCLUSION Sintered ceramic onlays placed with and without metal reinforcement showed a similar incidence of bulk fracture in molars. Preparations for both types of onlays were similar.
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