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Jurado CA, Afrashtehfar KI, Robles M, Alaqeely RS, Alsayed HD, Lindquist TJ, Alhotan A. Effect of preparation design and endodontic access on fracture resistance of zirconia overlays in mandibular molars: An in vitro study. J Prosthodont 2024. [PMID: 38734932 DOI: 10.1111/jopr.13865] [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] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2023] [Accepted: 04/17/2024] [Indexed: 05/13/2024] Open
Abstract
PURPOSE To evaluate the fracture resistance of zirconia overlays, considering various preparation designs and the presence of endodontic access. MATERIALS AND METHODS Ninety translucent zirconia (5Y-PSZ) overlay restorations were divided into six groups (n = 15/group) based on different preparation designs, with and without endodontic access: chamfer margin 4 mm above the gingival level without (group 1) and with endodontic access (group 2); margin 2 mm above the gingival level without (group 3) and with endodontic access (group 4); overlay with no chamfer margin without (group 5) and with endodontic access (group 6). Restorations were bonded to mandibular first molar resin dies, and the groups with endodontic access were sealed with flowable resin composite. All restorations underwent 100,000 cycles of thermal cycling between 5°C and 55°C, followed by loading until fracture. Maximum load and fracture resistance were recorded. ANOVA with Tukey post-hoc tests were used for statistical comparison (α < 0.05). RESULTS Fracture resistance significantly varied among overlay designs with and without endodontic access (p < 0.001), except for the no-margin overlays (groups 5 and 6). Overlays with a 2 mm margin above the gingival margin with endodontic access (group 4) exhibited significantly higher fracture resistance compared to both the 4-mm supragingival (group 2) and no-margin (group 6) designs, even when compared to their respective intact groups (groups 1 and 5). There were no significant differences between the no-margin and 4-mm supragingival overlays. CONCLUSION The more extensive zirconia overlay for mandibular molars is the first choice since the 2 mm margin above the gingival level design withstood considerable loads even after undergoing endodontic access. A no-margin overlay is preferred over the 4-mm supragingival design as it preserves more tooth structure and there was no outcome difference, irrespective of endodontic access. Caution is warranted in interpreting these findings due to the in vitro nature of the study.
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Affiliation(s)
- Carlos A Jurado
- Operative Dentistry Division, Department of General Dentistry, University of Tennessee Health Science Center College of Dentistry, Memphis, Tennessee, USA
| | - Kelvin I Afrashtehfar
- Department of Reconstructive Dentistry and Gerodontology (RekGero), School of Dental Medicine, University of Bern, Bern, Switzerland
- Evidence-Based Practice Unit (EBPU), Clinical Sciences Department, College of Dentistry, Ajman University, Ajman City, UAE
- Prosthodontics Private Practice, Dental Clinics, Abu Dhabi, UAE
- Artificial Intelligence Research Center (AIRC), Ajman University, Dubai, UAE
| | - Manuel Robles
- Department of Restorative Dentistry, Universidad del Valle De Mexico, Hermosillo, Sonora, Mexico
| | - Razan S Alaqeely
- Department of Periodontics, College of Dentistry, King Saud University, Riyadh, Saudi Arabia
| | - Hussain D Alsayed
- Department of Prosthetic Dental Sciences, College of Dentistry, King Saudi University, Riyadh, Saudi Arabia
| | - Terry J Lindquist
- Department of Prosthodontics, The University of Iowa College of Dentistry and Dental Clinics, Iowa City, Iowa, USA
| | - Abdulaziz Alhotan
- Dental Health Department, College of Applied Medical Sciences, King Saud University, Riyadh, Saudi Arabia
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Jurado CA, Amarillas-Gastelum C, Tonin BSH, Nielson G, Afrashtehfar KI, Fischer NG. Traditional versus conservative endodontic access impact on fracture resistance of chairside CAD-CAM lithium disilicate anterior crowns: An in vitro study. J Prosthodont 2023; 32:728-734. [PMID: 36471494 DOI: 10.1111/jopr.13625] [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] [Subscribe] [Scholar Register] [Received: 10/01/2022] [Revised: 11/04/2022] [Accepted: 11/26/2022] [Indexed: 12/12/2022] Open
Abstract
PURPOSE To evaluate the effect of traditional and conservative endodontic access hole preparation on fracture resistance of chairside computer-aided design and computer-aided manufacturing (CAD-CAM) lithium disilicate maxillary right central incisor crowns. MATERIALS AND METHODS Fifty-seven milled lithium disilicate maxillary right central incisor crowns were designed and fabricated with a chairside CAD-CAM system (Planmeca Romexis, Planmeca). The abutment preparation had a 1.0 mm incisal reduction and 1.0 mm chamfer finish. The restorations were bonded with resin cement to printed resin dies (n = 19 per group) and were treated and divided into three groups, (1) no endodontic access, (2) traditional triangular endodontic access, and (3) conservative ovoidal endodontic access. The endodontic access of the crowns was sealed with flowable resin composite. Restorations were subjected to 10,000 cycles of thermal cycling between 5° and 55°C. Then, restorations were loaded and exposed to compressive loading force, and the crack initiation (CI) and complete fracture (CF) were recorded. SEM micrographs of broken specimens on the printed dies were captured. ANOVA test and Bonferroni's correction were used for statistical comparison. RESULTS The fracture resistance among the three groups varied. Crowns with no endodontic access displayed significantly (p < 0.001) higher resistance [CI: 1025 (121) N; CF 1134 (127) N], followed by crowns with conservative ovoidal endodontic access [CI: 924 (60) N; CF: 1000 (72) N. Crowns with traditional triangular endodontic access showed the significantly (p < 0.001) lowest fracture resistance [CI: 635 (82) N; CF: 709 (75) N]. CONCLUSION The fracture resistance of chairside CAD-CAM lithium disilicate maxillary anterior crowns is influenced by the type of endodontic access provided. Conservative ovoidal endodontic access provides crowns with higher fracture resistance than traditional triangular endodontic access. Crowns with no endodontic access provided the highest resistance than other types of endodontic access.
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Affiliation(s)
- Carlos A Jurado
- Texas Tech University Health Sciences Center El Paso Woody L. Hunt School of Dental Medicine, El Paso, Texas
| | | | - Bruna Santos Honório Tonin
- Department of Dental Materials and Prosthetics, University of Sao Paulo School of Dentistry of Ribeirao Preto, Ribeirao Preto, Brazil
| | - Gentry Nielson
- Texas Tech University Health Sciences Center El Paso Woody L. Hunt School of Dental Medicine, El Paso, Texas
| | - Kelvin I Afrashtehfar
- Clinical Sciences Department, Ajman University Dental College, Ajman City, United Arab Emirates
- Department of Reconstructive Dentistry and Gerodontology, School of Dental Medicine, University of Bern, Berne, Switzerland
| | - Nicholas G Fischer
- Minnesota Dental Research Center for Biomaterials and Biomechanics, University of Minnesota School of Dentistry, Minneapolis, Minnesota
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Mauney Iii DK, Versluis A, Tantbirojn D, Cosby HT, Phebus JG. File Breakage in Conventional Versus Contracted Endodontic Cavities. Eur Endod J 2023; 8:262-267. [PMID: 38219039 PMCID: PMC10500211 DOI: 10.14744/eej.2023.41033] [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] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Revised: 05/24/2023] [Accepted: 05/25/2023] [Indexed: 01/15/2024] Open
Abstract
OBJECTIVE To compare rotations to failure and tip separation length of a nickel-titanium (Ni-Ti) rotary in- strument within a simulated mesio-buccal canal of a mandibular molar with a conventional or contracted endodontic cavity. METHODS Two identical lithium disilicate #30 crowns were milled. A conventional or contracted endodontic cavity was prepared. A custom glass tube was fabricated with taper and length replicating a mesio-buccal canal, including buccal and lingual curvature, and placed at the mesio-buccal orifice of each crown, held in a silicone mold. Instrumentation was simulated using 30/.04 Ni-Ti rotary files following manufacturer recommended 1.8 Nm torque and 500 RPM (n=20 per access type). Instrumentation was video recorded to determine time (sec- onds) and rotations to failure. The length of broken tips was measured. The experimental data were compared using a t-test (significance level 0.05). Stresses in the instruments were examined using finite element analysis. RESULTS Number of rotations to failure (mean±standard deviation) was 599±126 for conventional and 465±65 and for contracted access; tip separation lengths (mean±standard deviation) were 3.99±0.29 for conventional and 4.90±1.02 mm for contracted access. Number of rotations to failure and tip separation lengths were signifi- cantly different between the two access openings (p<0.001). Finite element analysis confirmed higher file curva- ture and accompanying higher stress levels with contracted access and the maximum stress further from the tip. CONCLUSION Within the limitations of this study, the contracted access caused earlier failure of the Ni-Ti in- strument with longer tip separation lengths than the conventional access due to higher stresses towards the middle section of the instrument. (EEJ-2022-11-143).
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Affiliation(s)
- Donald K. Mauney Iii
- Department of Endodontics, University of Tennessee Health Science Center, College of Dentistry, Tennessee, USA
| | - Antheunis Versluis
- Department of Bioscience Research, University of Tennessee Health Science Center, College of Dentistry, Tennessee, USA
| | - Daranee Tantbirojn
- Department of General Dentistry, University of Tennessee Health Science Center, College of Dentistry, Tennessee, USA
| | - Harry T. Cosby
- Department of Endodontics, University of Tennessee Health Science Center, College of Dentistry, Tennessee, USA
| | - Jeffrey G. Phebus
- Department of Endodontics, University of Tennessee Health Science Center, College of Dentistry, Tennessee, USA
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Abusteit OE, Hosney S, ElSheshtawy AS, Zapata RO. Outcome of Endodontic Treatment through Existing Full Coverage Restorations: An Endodontic Practice Case Series. J Endod 2021; 48:388-395. [PMID: 34843799 DOI: 10.1016/j.joen.2021.11.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2021] [Revised: 10/31/2021] [Accepted: 11/20/2021] [Indexed: 12/30/2022]
Abstract
INTRODUCTION This case series assessed the outcome of nonsurgical endodontic treatment completed through retained full coverage restorations (FCRs) in a board-certified endodontist private practice. The number of cases completed by the first author was 153. METHODS All cases were performed following a standardized protocol for treatment and restoration depending on the type of FCR. Number of cases that showed up for 2- to 4-year follow-up was 127, with 83% recall rate. The age range of patients was 33-95 years, with mean age of 54.734 years. The mean recall time was 2.448 years. FCRs and their distribution were as follows: 4 anterior teeth, 14 premolars, and 109 molars. There were 103 nonsurgical root canal treatments and 24 retreatments. Patients who presented for recall had 74 porcelain fused to metal crowns, 17 zirconia crowns, 15 abutments of porcelain fused to metal bridges, 14 lithium disilicate crowns, 5 gold crowns, 1 full metal crown, and 1 gold onlay. RESULTS There were no endodontically related failures. Six cases failed; 3 were due to vertical root fractures, 1 was due to horizontal root fracture, and 2 were due to extensive recurrent caries causing restorative failure. The percentage of healed cases following the American Association of Endodontists outcome criteria adopted in 2004 with intact retained FCR was 95.3%. CONCLUSIONS The results suggest predictable favorable outcomes for nonsurgical endodontic treatment through FCR following the proposed protocol for diagnosis, treatment, and restoration.
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Affiliation(s)
- Omar E Abusteit
- Division of Endodontics, School of Dentistry, University of Minnesota, Minneapolis, Minnesota.
| | - Sherif Hosney
- Division of Prosthodontics, College of Dentistry, University of Florida, Gainesville, Florida
| | - Ahmed S ElSheshtawy
- Department of Endodontics, Faculty of Dentistry, Cairo University, Cairo, Egypt
| | - Ronald Ordinola Zapata
- Division of Endodontics, School of Dentistry, University of Minnesota, Minneapolis, Minnesota
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Schubert J, Kirkpatrick T, Roberts H. The effect of endodontic access preparation on the failure load resistance of a 3Y-TZP monolithic zirconia crown. AUST ENDOD J 2021; 48:138-143. [PMID: 34258848 DOI: 10.1111/aej.12544] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Revised: 06/20/2021] [Accepted: 06/30/2021] [Indexed: 11/29/2022]
Abstract
The effect of endodontic access preparation on the failure load resistance of 3Y-TZP zirconia crowns was accomplished by preparing human molars and luting monolithic zirconia crowns with a self-adhesive resin cement. Besides the intact control, teeth received endodontic access preparations and then grouped (n = 12) into a positive control (no access repair), dentin core replacement only and complete access repair groups. Specimens were axially tested until failure with results of no significant difference between the failure load of intact controls and the complete access repair group. However, the positive control and dentin replacement only groups failed at significantly lower loads. Under the conditions of this study, there was no significant failure load difference between 3Y-TZP monolithic zirconia crowns with repaired endodontic access preparations to that evidenced by an unprepared control. Although this evidence is encouraging, caution is advised and definitive recommendations cannot be made until verified by clinical studies.
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Affiliation(s)
| | | | - Howard Roberts
- University of Kentucky College of Dentistry, Lexington, Kentucky, USA
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Simon JC, Kwok JW, Vinculado F, Fried D. Computer-Controlled CO 2 Laser Ablation System for Cone-beam Computed Tomography and Digital Image Guided Endodontic Access: A Pilot Study. J Endod 2021; 47:1445-1452. [PMID: 34119563 PMCID: PMC8867881 DOI: 10.1016/j.joen.2021.06.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [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: 03/30/2021] [Revised: 06/03/2021] [Accepted: 06/05/2021] [Indexed: 11/25/2022]
Abstract
Introduction: Ideal endodontic access provides unobstructed entry to the pulp chamber and visualization of the canal orifices while preserving the maximum amount of tooth structure. The aim of this study was to implement the use of lasers to accurately and predictably access teeth to follow the principles of minimally invasive endodontics. Methods: Traditional, conservative, ultraconservative, bridge, truss, and orifice-directed accesses were performed. A computer-controlled 9.3-μm CO2 laser ablation system was assembled and coupled with custom software capable of combining cone-beam computed tomographic (CBCT) volumetric data with spatially calibrated digital images of teeth to provide an augmented reality environment for designing and preparing endodontic accesses. Twenty (N = 20) sound posterior teeth with fully developed root canal systems were imaged with CBCT scans and accessed via laser ablation in vitro. Results: All 20 (20/20) teeth were successfully accessed without iatrogenic errors. Volumetric renderings from post-access CBCT scans were used to verify the access and determine accuracy qualitatively. The volumetric measurements of hard tissue removed were as follows: traditional = 39.41 mm3, conservative = 9.76 mm3, ultraconservative = 7.1 mm3, bridge = 11.53 mm3, truss = 19.21 mm3, and orifice directed = 16.86 mm3. Conclusions: Digital image guidance based on feature recognition and registration with CBCT data is a viable method to address the challenge of dynamic navigation for accessing the pulp chamber. Modern lasers with high pulse repetition rates integrated with computer-controlled scanning systems are suitable for the efficient cutting of dental hard tissues.
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Affiliation(s)
- Jacob C Simon
- Department of Preventive and Restorative Dental Sciences, University of California San Francisco, San Francisco, California.
| | - Jason W Kwok
- Department of Endodontology, University of Connecticut, Farmington, Connecticut
| | - Frank Vinculado
- Department of Preventive and Restorative Dental Sciences, University of California San Francisco, San Francisco, California
| | - Daniel Fried
- Department of Preventive and Restorative Dental Sciences, University of California San Francisco, San Francisco, California
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Tsotsis P, Dunlap C, Scott R, Arias A, Peters OA. A survey of current trends in root canal treatment: access cavity design and cleaning and shaping practices. AUST ENDOD J 2020; 47:27-33. [PMID: 33030288 DOI: 10.1111/aej.12449] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Accepted: 09/16/2020] [Indexed: 01/26/2023]
Abstract
The purpose of this study was to evaluate current trends in access cavity design and cleaning and shaping among endodontists. A survey was e-mailed to active members of the American Association of Endodontists. Data showed that most respondents used traditional (57%) or conservative (43%) access cavities; less than 1% reported using ultraconservative access cavities. A glide path was created by 93% of respondents; NaOCl was used as lubricant by 51% of respondents, while 28% used RC Prep, 9% used liquid EDTA, 7% used Glyde, and 2% did not use any lubricant. Most respondents used NaOCl at 5.25% or higher concentration. Smear layer was removed by 92% of endodontists. Apical gauging was mostly accomplished with hand files. Clinical preferences varied among surveyed endodontists and among different age groups. Currently, very few endodontists use ultraconservative access preparations. There was large variation among the respondents suggesting a possible need for quality guidelines.
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Affiliation(s)
- Polymnia Tsotsis
- Department of Endodontics, Arthur A. Dugoni School of Dentistry, University of the Pacific, San Francisco, California, USA
| | - Craig Dunlap
- Department of Endodontics, Arthur A. Dugoni School of Dentistry, University of the Pacific, San Francisco, California, USA
| | - Raymond Scott
- Department of Endodontics, Arthur A. Dugoni School of Dentistry, University of the Pacific, San Francisco, California, USA
| | - Ana Arias
- Department of Conservative Dentistry, School of Dentistry, Complutense University, Madrid, Spain
| | - Ove A Peters
- Department of Endodontics, Arthur A. Dugoni School of Dentistry, University of the Pacific, San Francisco, California, USA.,School of Dentistry, University of Queensland, Herston, Queensland, Australia
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