A Comparitive Evaluation of the Marginal Adaptation of Zirconium Coping and Nickel–Chromium Coping Using Shoulder Finish Line Design: An Invitro Study

ABSTRACT Objective: To evaluate the marginal gap (MG) and absolute marginal discrepancy (MD) of full ceramic crowns with two finish line designs, shoulder and chamfer, using microcomputed tomography (micro-CT) before and after cementation. Materials and Methods: Sixty extracted human maxillary premolar teeth were divided into two groups based on the finish line design: Group I: 90° shoulder and Group II: 135° chamfer. The specimens were further grouped based on the type of full ceramic crown they received: Group A: Feldspathic Cerec inLab ceramic system, Group B: Cerec inLab aluminum oxide ceramic system and Group C: Lithium disilicate press ceramic system. Before cementation, five crowns from each group were scanned using micro-CT in two sections, sagittal and coronal, to determine the MG and MD values for four regions of the crown (sagittal buccal, sagittal lingual, coronal mesial and coronal distal). After cementation and thermal cycling, the scanning was repeated. Measurements were obtained from 10 points for each region, 80 points totally, to evaluate the MG and MD values. Files were processed using NRecon and CTAn software. Results were statistically analyzed using one- and two-way ANOVA and Tukey HSD tests (P = 0.05). Results: Full ceramic systems showed clinically acceptable marginal adaptation values. The Feldspathic Cerec inLab ceramic system generally presented the lowest variance, except in the MG values of the coronal mesial region. The MG and MD values of all ceramics increased significantly after cementation, except in the shoulder preparation design (sagittal buccal region) for MG and in the chamfer preparation design (sagittal lingual region) for MD values. Conclusions: Full-ceramic crowns showed clinically acceptable marginal adaptation values. The Feldspathic Cerec inLab ceramic system (Vitablocs Mark II) generally presented the lowest variance when compared with the other ceramics, except for the MG values on the mesial surface of the coronal section.

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EFFECT OF FINISH LINE DESIGN AND THERMO-MECHANICAL AGING ON THE FRACTURE RESISTANCE OF TWO TYPES OF MONOLITHIC ZIRCONIA CROWNS

Egyptian Dental Journal ◽

10.21608/edj.2017.76461 ◽

2017 ◽

Vol 63 (4) ◽

pp. 3947-3953

Author(s):

Khaled Haggag ◽

Mohammed Hosny ◽

Muhammad Abbas ◽

Hussein Ramadan

Keyword(s):

Fracture Resistance ◽

Finish Line ◽

Zirconia Crowns ◽

Monolithic Zirconia ◽

Line Design ◽

Mechanical Aging

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Marginal Integrity of CAD/CAM Ceramic Crowns Using Two Different Finish Line Designs

Medical Principles and Practice ◽

10.1159/000516833 ◽

2021 ◽

Author(s):

Jaber Hussain Akbar ◽

Ridwaan Omar ◽

Yacoub Al Tarakmah

Keyword(s):

Dental Treatment ◽

Statistical Significance ◽

United States Public Health ◽

Finish Line ◽

Marginal Integrity ◽

Computer Aided ◽

Cad Cam ◽

Group A ◽

Group B ◽

Line Design

Statement of problem- Research on evaluation of crowns made by the latest CAD/CAM systems for their marginal adaptation is scarce. Purpose- 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 two different finish line preparation designs: Chamfer and Shoulder. Material and methods- Typhodont teeth were equally divided into two groups, group A and B. The teeth were prepared for full coverage crowns with a shoulder (group A) and chamfer finish line design (group B). An experienced prosthodontist prepared all crown preparations. Evaluation of six sites per sample was completed by two calibrated, experienced prosthodontists using the modified United States 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 two crowns in group A and one crown in group B were clinically unacceptable. There was no statistical significance (p=0.282) between the two groups regarding finish-line design. Conclusions- CEREC system provides clinically acceptable crowns and can safely be utilized in dental treatment. Therefore, Contemporary Dental Computer-Aided Design/Computer-Aided Manufacturing (CAD/CAM) restorations should be considered as a safe treatment modality by dental professionals.

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Marginal Adaptation of Cerec 3 CAD/CAM Composite Crowns Using Two Different Finish Line Preparation Designs

Journal of Prosthodontics ◽

10.1111/j.1532-849x.2006.00095.x ◽

2006 ◽

Vol 15 (3) ◽

pp. 155-163 ◽

Cited By ~ 43

Author(s):

Jaber Hussain Akbar ◽

Cynthia S. Petrie ◽

Mary P. Walker ◽

Karen Williams ◽

J. David Eick

Keyword(s):

Marginal Adaptation ◽

Finish Line ◽

Cad Cam

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Comparison of microleakage between different restorative materials to restore marginal gap at crown margin

PeerJ ◽

10.7717/peerj.10823 ◽

2021 ◽

Vol 9 ◽

pp. e10823

Author(s):

Satheesh B. Haralur ◽

Ghaseb Ahmed AL Ghaseb ◽

Norah Ali Alqahtani ◽

Bader Alqahtani

Keyword(s):

Structural Defect ◽

Structural Defects ◽

Glass Ionomer ◽

Marginal Gap ◽

Finish Line ◽

Nickel Chromium ◽

Carious Lesions ◽

Luting Cement ◽

Molar Teeth ◽

Defect Dimension

Background An occurrence of secondary caries around the indirect restoration margin is reported to remain a leading cause of failures. Objective This study aimed to test the interfacial microleakage of conventional glass-ionomer (CGI), resin-modified glass ionomer (RMGI) and Nano-hybrid composite (CR) restorations at a full veneer margin crown. Methods Ninety human extracted molar teeth were divided into three groups (n = 30). Each group was subdivided into three subgroups (n = 10) according to the extent of the structural defects; The structural defect in G1 had a depth of 1.5 mm, width and length at 2 mm and 1 mm intrusion within the crown cervical margin. The corresponding structural defect dimension values for G2 were 2, 5, 4 and 2 mm with defects extending onto the root structure. Meanwhile, G3: structural deficiency of 2 mm depth, 3 mm width and 3 mm length and with 1.5 mm extension into the prepared teeth. These structural defects in each subgroup were restored with CGI, RMGI and CR. Artificial carious lesion formation was induced at the cervical finish line with a demineralizing solution. The artificial carious lesions were restored as per the group distribution. Subsequently, teeth samples were prepared and cemented with Nickel-chromium full coverage restorations utilizing glass-ionomer luting cement. Teeth samples were thermocycled, isolated with nail varnish, and immersed in 0.1% methylene blue for 24 h. The teeth samples were sectioned longitudinally, dye penetration was evaluated with a stereomicroscope. The data were analyzed with Kruskal–Wallis and Mann–Whitney U tests. Results CGI-G1 recorded the highest micro-leakage score at 1.450; while CR-G3 recorded the least score (0.350). At a cementum-restoration interface, CR-G1 (0.850) documented the lowest micro-leakage; RMGI-G3 had a greater value at 1.700. Conclusions The hybrid CR could be effectively used to restore the restoration of a marginal gap around crown margins.

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Bond Strength and Microleakage of Different Designs of Occlusal Veeners

NeuroQuantology ◽

10.14704/nq.2021.19.1.nq21009 ◽

2021 ◽

Vol 19 (1) ◽

pp. 62-66

Author(s):

Mohamed G. Hussein ◽

Cherif A. Mohsen

Keyword(s):

Standard Deviation ◽

Bond Strength ◽

Fracture Strength ◽

Lithium Disilicate ◽

Mean Value ◽

P Value ◽

Finish Line ◽

Nonsignificant Difference ◽

Diamond Saw ◽

Line Design

The purpose of this study was to investigate fracture strength of different lithium disilicate occlusal veneers designs with different tooth preparations. Material and method: Fifty-six extracted human mandibular molars were collected with relatively comparable size and standardization done by diamond saw and it will receive. 6mm lithium disilicate occlusal veneers. Specimens will be divided into two main groups, each of these groups contains 28 samples (group A&B), the first group represents occlusal veneers with 1.0 ml with radial shoulder finish line design includes axial surfaces for a2 ml length, while the second group represents occlusal veneers preparation without finish line. Each main group will be subdivided into 2 subtypes groups (A1, A2, B1, B2), each subtype group contains 14 samples, the first subtype group will receive a buccal groove, while the second subgroup will be without grooves. Each subgroup will be divided into 2 classes (7 samples) according to the type of test it will be subjected to: microleakage, bond strength. Results: The fracture strength is (mean value+ standard deviation) in plain occlusal reduction without vs with buccal groove(890.36±42.51N), (865.69±36.79N). The fracture strength is (mean value ± standard deviation) in occlusal reduction with radial shoulder, without or with buccal groove (835.36±42.51N), (820.69±36.79N), with nonsignificant difference p value <0.05. Conclusions: All tested occlusal veneer designs proved to withstand normal and parafunctional masticatory forces with non-significant statistical difference.

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