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Nasir MQ, kadhim AJ. Marginal adaptation of different monolithic zirconia crowns with horizontal and vertical finish lines: A comparative in vitro study. J Dent Res Dent Clin Dent Prospects 2023; 17:235-241. [PMID: 38584994 PMCID: PMC10998165 DOI: 10.34172/joddd.2023.40589] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2023] [Accepted: 10/25/2023] [Indexed: 04/09/2024] Open
Abstract
Background This study evaluated the influence of different tooth preparation techniques and zirconia materials on marginal adaptation. Methods Forty-eight healthy human maxillary first premolars were divided into two primary groups based on preparation design: group A (chamfer) and group B (vertical). Within each main group, there were three subgroups, comprising eight teeth each, distinguished by the type of zirconia material employed (Zircad LT, MT, and Prime by Ivoclar Vivadent). All the samples were prepared by the same operator using a dental surveyor. Intraoral scanning was performed on the prepared teeth. SironaInLab CAD 20.0 software was used to design crowns, which were subsequently generated using a 5-axis milling machine. The crowns were cemented to their respective teeth with self-adhesive resin cement. Marginal gap measurements were taken in micrometers (μm) before and after cementation at 16 sites per sample using a digital microscope at×230 magnification. The collected data were evaluated using statistical analysis using the independent t-test, paired t-test, and ANOVA at an 0.05 significance level. Results The vertical preparation group exhibited the smallest marginal gap, while the chamfer group displayed the largest. This disparity was statistically significant (P<0.05) for pre- and post-cementation measurements across all materials. There were no significant differences between the different monolithic zirconia crowns. Conclusion The vertical preparation design illustrated significantly better marginal adaptation than the chamfer preparation design. Comparisons between materials showed comparable marginal gaps. The mean values of the marginal gaps in all groups increased significantly after cementation.
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Affiliation(s)
- Mohammed Qasim Nasir
- Department of Restorative and Aesthetic Dentistry, College of Dentistry, University of Baghdad, Baghdad, Iraq
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Abstract
OBJECTIVE This study aimed to evaluate the effect of different chamfer preparations on the load capacity of reattached fractured incisors under lingual loading. METHODS Eighty #8 typodonts were randomly assigned to four groups (n = 20 each). They were sectioned to simulate crown fracture, and reattached with a self-etch adhesive and a resin composite. The preparation for each group was: (1) no chamfer; (2) buccal chamfer; (3) lingual chamfer; and (4) circumferential chamfer. Forty-eight human lower incisors were grouped and prepared similarly (n = 12 each). These teeth were tested for their load capacity under a lingual load on a universal testing machine. Finite element models were used to examine the stresses on the reattached surfaces to help interpret the experimental results. RESULTS The buccal chamfer did not increase the load capacity when compared with the no-chamfer group. Lingual and circumferential chamfers respectively increased the fracture load by 36.9% and 32.3% in typodonts, and 78.5% and 33.3% in human incisors. The increase was statistically significant (p < 0.05). A higher fracture load tended to be accompanied by a larger area of deflected cohesive fracture. Finite element analysis showed that lingual and circumferential chamfers reduced the fracture-causing tensile stress at the lingual margin of the reattachment interface by approximately 70% and 60%, respectively, in human upper incisors. SIGNIFICANCE It was the joint design, and not the size of the bond area, that affected the load capacity of reattached incisors. Among the preparations considered, only those with a lingual chamfer could increase the load capacity of reattached incisors under a lingual load.
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Affiliation(s)
- Lu Zhang
- The State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) & Key Laboratory of Oral Biomedicine Ministry of Education, School & Hospital of Stomatology, Wuhan University, Wuhan, China; Minnesota Dental Research Center for Biomaterials and Biomechanics (MDRCBB), School of Dentistry, University of Minnesota, MN, USA
| | - Ning Ye
- Minnesota Dental Research Center for Biomaterials and Biomechanics (MDRCBB), School of Dentistry, University of Minnesota, MN, USA
| | - Wondwosen A Aregawi
- Minnesota Dental Research Center for Biomaterials and Biomechanics (MDRCBB), School of Dentistry, University of Minnesota, MN, USA
| | - Alex Fok
- Minnesota Dental Research Center for Biomaterials and Biomechanics (MDRCBB), School of Dentistry, University of Minnesota, MN, USA.
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Akbar JH, Omar R, Al-Tarakmah Y. Marginal Integrity of CAD/CAM Ceramic Crowns Using Two Different Finish Line Designs. Med Princ Pract 2021; 30:443-447. [PMID: 33902029 PMCID: PMC8562050 DOI: 10.1159/000516833] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Accepted: 04/25/2021] [Indexed: 11/19/2022] Open
Abstract
OBJECTIVE Research on evaluation of crowns made by the latest contemporary dental computer-aided design/computer-aided manufacturing (CAD/CAM) systems for their marginal adaptation is scarce. The purpose of this in vitro study was to evaluate the marginal integrity of crowns fabricated by the latest Chairside Economical Restorations of Esthetic Ceramic (CEREC) system using 2 different finish line preparation designs: chamfer and shoulder. MATERIALS AND METHODS Typodont teeth were divided equally into 2 groups, A and B. The teeth were prepared for full coverage crowns with a shoulder (group A) and chamfer (group B) finish line design. An experienced prosthodontist prepared all crown preparations. Evaluation of 6 sites per sample was completed by 2 calibrated, experienced prosthodontists using the modified US Public Health Services (USPHS) criteria. The descriptive statistics and Z-test were used to evaluate the results. RESULTS A total of 180 teeth were included in the study (90 teeth in each group). Only 2 crowns in group A and 1 crown in group B were clinically unacceptable. There was no statistical significance (p = 0.282) between the 2 groups regarding finish line design. CONCLUSIONS The CEREC system provides clinically acceptable crowns and can safely be utilized in dental treatment. Therefore, CAD/CAM restorations could be considered as a safe treatment modality by dental professionals.
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Bommanagoudar J, Chandrashekhar S, Sharma S, Jain H. Comparison of Enamel Preparations - Bevel, Chamfer and Stair Step Chamfer on Fracture Resistance of Nano Filled Resin Composites Using Bulk Pack Technique - An In Vitro Study. Open Access Maced J Med Sci 2019; 7:4089-4093. [PMID: 32165958 PMCID: PMC7061382 DOI: 10.3889/oamjms.2019.853] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2019] [Revised: 11/04/2019] [Accepted: 11/05/2020] [Indexed: 11/25/2022] Open
Abstract
AIM: To evaluate and compare the effect of enamel preparation designs bevel, chamfer and stair-step chamfer on the fracture resistance of nanocomposite. METHODS: The sample group of this study consisted of 72 non-carious permanent maxillary central incisors. The sample is divided into four groups of 18 each. Group, I control Group II bevel preparation, Group III chamfer preparation, group IV stair step chamfer preparation. After the specific preparation, each tooth is filled with nanocomposite using bulk pack technique. The teeth were subjected to fracture resistance test under Universal testing machine and then were examined under a stereomicroscope to evaluate the type of bond failure. The results were subjected to statistical analysis. RESULTS: Results of the One-Way ANOVA revealed a significant difference in the mean peak failure load values of the four different groups. (P < 0.001) Tukey’s Post-Hoc comparison test revealed that there was a significant difference in the mean peak failure load values of the bevel and chamfer preparation. But there was no significant difference between chamfer and stair-step chamfer preparation designs. CONCLUSION: Stair-step chamfer preparation demonstrated comparable values to Chamfer preparation but also involved the removal of less amount of tooth structure adjacent to the fractured edge and good esthetic technique.
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Affiliation(s)
- Jyothi Bommanagoudar
- Department of Pedodontics and Preventive Dentistry, SMBT Dental College and Hospital, Sanagmner, Maharashtra 422608, India
| | - Shashidhar Chandrashekhar
- Conservative Dentistry and Endodontics, SMBT Dental College and Hospital, PAHER University Rajasthan, Sangamner, Maharashtra, India
| | - Shilpa Sharma
- Department of Oral Medicine and Radiology, SMBT Dental College and Hospital, Sanagmner, Maharashtra 422608, India
| | - Hiten Jain
- Department of Public Health Dentistry, SMBT Dental College and Hospital, Sanagmner, Maharashtra 422608, India
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Pahlevan A, Mirzaee M, Yassine E, Ranjbar Omrany L, Hasani Tabatabaee M, Kermanshah H, Arami S, Abbasi M. Enamel thickness after preparation of tooth for porcelain laminate. J Dent (Tehran) 2014; 11:428-32. [PMID: 25584054 PMCID: PMC4283744] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Subscribe] [Scholar Register] [Received: 02/02/2014] [Accepted: 06/07/2014] [Indexed: 11/02/2022]
Abstract
OBJECTIVE In this investigation the thickness of enamel in the gingival, middle, and incisal thirds of the labial surface of the anterior teeth were measured regarding preparation of the teeth for porcelain laminate veneers. MATERIALS AND METHODS Part one, 20 extracted intact human maxillary central and lateral incisors ten of each were selected. The teeth were imbedded in autopolimerize acrylic resin. Cross section was preformed through the midline of the incisal, middle and cervical one-third of the labial surface of the teeth. The samples were observed under reflected stereomicroscope and the thickness of enamel was recorded. Part II, the effect of different types of preparation on dentin exposure was evaluated. Thirty maxillary central incisor teeth were randomly divided into two groups: A: Knife-edge preparation. B: Chamfer preparation. All samples were embedded in autopolimerize acrylic resin using a silicon mold. The samples were cut through the midline of the teeth. The surface of the samples were polished and enamel and dentin were observed under the stereomicroscope. RESULTS Data were analyzed by ANOVA-one way test. The results of this study showed that the least enamel thickness in the central incisor was 345 and in lateral incisor is 235 μ this thickness is related to the one-third labial cervical area. Maximum thickness in maxillary central and lateral incisors in the one-third labial incisal surface was 1260 μ and 1220μ, respectively. In the second part of the study, the tendency of dentinal exposure was shown with the chamfer preparation, but no dentinal exposure was found in the knife-edge preparation. The differences between groups were significant (p<0.05). CONCLUSION The knowledge of enamel thickness in different part of labial surface is very important. The thickness of enamel in the gingival area does not permit a chamfer preparation. The knife edge preparation is preferable in gingival area.
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Affiliation(s)
- Ayoub Pahlevan
- Associate Professor, Dental Research Center Dentistry Research Institute, Department of Operative Dentistry, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran
| | - Mansoreh Mirzaee
- Assistant Professor, Dental Research Center Dentistry Research Institute, Department of Operative Dentistry, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran,Corresponding author: M Mirzaei, Department of Dental Research Center Dentistry Research Institute, Department of Operative Dentistry, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran,
| | - Esmaeil Yassine
- Professor, Dental Research Center Dentistry Research Institute, Department of Operative Dentistry, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran
| | - Ladan Ranjbar Omrany
- Assistant Professor, Dental Research Center Dentistry Research Institute, Department of Operative Dentistry, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran
| | - Masumeh Hasani Tabatabaee
- Associate Professor, Dental Research Center Dentistry Research Institute, Department of Operative Dentistry, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran
| | - Hamid Kermanshah
- Associate Professor, Dental Research Center Dentistry Research Institute, Department of Operative Dentistry, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran
| | - Sakineh Arami
- Assistant Professor, Dental Research Center Dentistry Research Institute, Department of Operative Dentistry, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran
| | - Mehdy Abbasi
- Assistant Professor, Dental Research Center Dentistry Research Institute, Department of Operative Dentistry, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran
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