1
|
Lim B, Kim D, Song JS, Kim S, Kim H, Shin Y. Influence of Post-Curing in Nitrogen-Saturated Condition on the Degree of Conversion and Color Stability of 3D-Printed Resin Crowns. Dent J (Basel) 2024; 12:68. [PMID: 38534292 DOI: 10.3390/dj12030068] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2024] [Revised: 02/19/2024] [Accepted: 03/04/2024] [Indexed: 03/28/2024] Open
Abstract
Post-curing is the process of applying extra light to complete the polymerization process of 3D printing. The mechanical properties of light-cured three-dimensional (3D) printed resin can be improved by decreasing the oxygen concentrations during post-curing, and nitrogen-saturated post-curing has been applied for this purpose. This study aimed to evaluate and compare the color stability of 3D-printed resin crowns that were post-cured in both normal air and nitrogen-saturated conditions. Crowns were fabricated with a 3D printer and post-cured in normal air (control group; air) or nitrogen-saturated conditions (experimental group; nitrogen). The specimens in each group were subdivided into four subgroups, each exposed to different discoloration agents: distilled water, coffee, wine, and curry. Post-immersion color changes were measured using a digital spectrophotometer and analyzed using repeated-measures ANOVA. Fourier transform infrared (FT-IR) spectroscopy evaluated the degree of conversion of resin over immersion times for both post-curing conditions. Upon comparing the effects of post-curing conditions, a significant difference between the control and experimental groups in terms of immersion time in the wine and curry subgroups was found. FT-IR analysis showed a significant difference in the degree of conversion between the air and nitrogen groups from 10 to 300 s. These findings suggest that nitrogen-saturated post-curing can potentially enhance the conversion rate of 3D-printed resin crowns, thereby improving their color stability.
Collapse
Affiliation(s)
- Bohyun Lim
- Department of Conservative Dentistry, College of Dentistry, Yonsei University, Seoul 03722, Republic of Korea
| | - Dohyun Kim
- Department of Conservative Dentistry, College of Dentistry, Yonsei University, Seoul 03722, Republic of Korea
| | - Je Seon Song
- Department of Pediatric Dentistry, College of Dentistry, Yonsei University, Seoul 03722, Republic of Korea
| | - Sunil Kim
- Department of Conservative Dentistry, College of Dentistry, Yonsei University, Seoul 03722, Republic of Korea
| | - Hoon Kim
- Research Institute of Agriculture and Life Sciences, College of Agriculture & Life Sciences, Seoul National University, Seoul 08826, Republic of Korea
| | - Yooseok Shin
- Department of Conservative Dentistry, College of Dentistry, Yonsei University, Seoul 03722, Republic of Korea
| |
Collapse
|
2
|
Peres TS, de Quirino Oliveira HL, Mendoza LCL, Ribeiro MTH, Carlo HL, Price RB, Soares CJ. Effect of four different mono and multi-wave light-curing units on the Knoop hardness of veneer resin composites. Dent Mater 2024; 40:80-89. [PMID: 37919111 DOI: 10.1016/j.dental.2023.10.019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Accepted: 10/20/2023] [Indexed: 11/04/2023]
Abstract
OBJECTIVES To evaluate the effect of mono and multi-wave light-curing units (LCUs) on the Knoop hardness of resin-based composites (RBC) that use different photoinitiators. METHODS Central incisor-shaped specimens 12 mm long, 9 mm wide, and 1.5 mm thick were made from 2 RBCs that use different photoinitiators: Tetric N-Ceram (Ivoclar Vivadent) - and Vittra APS (FGM), both A2E shade. They were light-cured with 4 different LCUs: two claimed to be multi-wave - VALO Grand (Ultradent) and Emitter Now Duo (Schuster); and two were monowave - Radii Xpert (SDI) and Elipar DeepCure-L (3 M Oral Care) using 2 different light exposure protocols: one 40 s exposure centered over the specimen; and two 20 s light exposures that delivered light from two positions to better cover the entire tooth. 16 groups with 10 specimens in each group were made. The Knoop hardness (KH, kg/mm2) was measured at the top and bottom of the specimen in the center and at the cervical, incisal, mesial, and distal peripheral regions. The active tip diameters (mm) and spectral radiant powers (mW/nm) of the LCUs were measured with and without the interposition of the RBC, as well as the radiant exposure beam profiles (J/cm²) delivered to the top of the RBCs. The data was analyzed using Three-way ANOVA and Tukey's tests (α = 0.05). RESULTS The VALO Grand (1029 mW) emitted twice the power of the Radii Xpert (500 mW). The KH values of VI and TN resin composite specimens were significantly affected by the LCU used (p < .001), the measurement location (p < .001), and the surface of the specimen (p < .001). LCUs with wider tip diameters produced greater Knoop hardness values at the peripheries of the 12 mm of long, 9 mm wide specimens. In general, the VALO Grand produced the highest KH values, followed by Elipar DeepCure-L, then by Radii Xpert. The Emitter Now Duo LCU produced the lowest values. Exposing the veneers from two locations reduced the differences between the LCUs and the effect of the measurement location. Only the VALO Grand could fully cover the composite veneer with light when the two locations were used. SIGNIFICANCE The light tip must cover the entire restoration to photocure the RBC beneath the light tip.
Collapse
Affiliation(s)
- Thiago Silva Peres
- School of Dentistry, UFU - Universidade Federal de Uberlândia, Uberlândia, MG, Brazil
| | | | | | | | - Hugo Lemes Carlo
- Dentistry Department, School of Dentistry, UFU - Universidade Federal de Uberlândia, MG, Brazil
| | - Richard Bengt Price
- Dental Clinical Sciences Department and School of Biomedical Engineering, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Carlos José Soares
- Dentistry Department, School of Dentistry, UFU - Universidade Federal de Uberlândia, MG, Brazil.
| |
Collapse
|
3
|
Bukhary DM, Al-Zain AO, Alshali RZ, Bukhary DM, Abdalla AN, Youssef AR. Effects of nanohybrid, flowable, resin-based composites on fibroblast viability using different light-curing units. J Prosthodont 2022. [PMID: 36018062 DOI: 10.1111/jopr.13599] [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: 01/13/2022] [Accepted: 08/14/2022] [Indexed: 11/27/2022] Open
Abstract
PURPOSE To investigate the in vitro cytotoxic effects of Bis-GMA-containing and Bis-GMA-free flowable resin-based composites (RBCs) on primary human gingival fibroblast cells (hGFc) using direct and indirect curing methods and three different light-curing units (LCUs) MATERIALS AND METHODS: Cells were isolated and cultured in vitro in 24-well plates. The plates were divided into treatment (cells with RBC), control (cells only), and blank (media only) groups. In the treatment groups, two types of nanohybrid flowable RBCs were used: Bis-GMA-free and Bis-GMA groups. Each treatment group was subdivided according to the curing method, i.e., direct curing (RBC was injected into the wells and cured directly on the attached cells) and indirect curing (the samples were pre-cured outside of the well plate and then added to the well plate with cells). To vary the LCU, the subgroups were further divided into three groups: multiple-emission peak light-emitting diode, single-emission peak light-emitting diode, and quartz-tungsten-halogen units. Curing was conducted for 20 s. The hGFc cytotoxicity was evaluated via 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) assay after 24, 48, and 72 h of culturing RESULTS: The MTT assay results showed that both RBCs were significantly cytotoxic toward hGFc compared to the control group (p < 0.0001). The Bis-GMA group was significantly more cytotoxic to the cells compared to the Bis-GMA-free group. In addition, the curing method and time interval affected cell viability regardless of the LCU used CONCLUSION: The Bis-GMA flowable RBC and direct curing method had the highest cytotoxic effects on hGFc regardless of the LCU used. Careful selection of flowable RBCs and proper curing techniques are required to decrease the cytotoxic effects on hGFc and improve the clinical handling of oral tissues. This article is protected by copyright. All rights reserved.
Collapse
Affiliation(s)
- Dalea M Bukhary
- Oral and Maxillofacial Prosthodontics Department, Faculty of Dentistry, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Afnan O Al-Zain
- Restorative Dentistry Department, Faculty of Dentistry, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Ruwaida Z Alshali
- Oral and Maxillofacial Prosthodontics Department, Faculty of Dentistry, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Deena M Bukhary
- Department of Pharmaceutics, College of Pharmacy, Umm Al-Qura University, Makkah, Saudi Arabia
| | - Ashraf N Abdalla
- Department of Pharmacology and Toxicology, College of Pharmacy, Umm Al-Qura University, Makkah, Saudi Arabia.,Department of Pharmacology and Toxicology, Medicinal and Aromatic plants research institute, National center for research, Khartoum, 2404, Sudan
| | - Abdel-Rahman Youssef
- Division of Basic Medical Science, Department of Basic and Clinical Oral Sciences, Faculty of Dentistry, Umm Al-Qura University, Makkah, Saudi Arabia.,Department of Microbiology and Immunology, Faculty of Medicine, Suez Canal University, Ismailia, Egypt
| |
Collapse
|
4
|
Oh S, Kim HJ, Kim HJ, Antonson SA, Kim SY. Influence of irradiation distance on the mechanical performances of resin composites polymerized with high-irradiance light curing units. Biomater Res 2022; 26:18. [PMID: 35596228 PMCID: PMC9123695 DOI: 10.1186/s40824-022-00267-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2022] [Accepted: 05/10/2022] [Indexed: 11/10/2022] Open
Abstract
Background The aim of this study was to evaluate the influence of increased irradiation distance on the flexural strength (FS), dentin micro-shear bond strength (μSBS), and the degree of conversion (DC) of bulk-fill flowable, conventional flowable, and packable resin composites. Methods The resin composites tested were Surefil® SDR™ (SDR), Filtek Z350 XT Flowable Restorative A2 shade (Z3F), and Filtek Z350 XT Universal Restorative A2 shade (Z3P). Specimens were cured at four irradiation distances (0, 2, 4, and 8 mm) with an Elipar DeepCure-S LED curing light for 20 s. FS tests were performed (n = 15) using bar-shaped specimens (8 mm × 2 mm × 2 mm) of the resin composites. μSBS tests were performed on the occlusal surfaces of extracted third molars from humans that were ground to expose dentin (n = 15). DC was measured by using Raman spectroscopy on the top and bottom surfaces of disk specimens (2-mm thick) (n = 3). To further investigate whether extended irradiation times could compensate for reduced irradiance, additional Z3P specimens were prepared, which were light-cured at 8-mm distances for 40 and 60 s and subjected to FS tests, μSBS tests, and Raman spectroscopy. Both two-way and one-way ANOVA were used for statistical analyses. Results Both FS and DC of Z3P specimens cured at an 8-mm distance were significantly lower than those cured at shorter distances (p < 0.05), whereas the FS and DC of the Z3F and SDR specimens were not significantly influenced by increasing distances. The μSBSs of the three types of resin composites reduced with increasing irradiation distances. The FS, μSBS, and DC of the Z3P specimen light-cured at 8 mm for 40 s were comparable to those of the Z3P specimen cured at 0 mm for 20 s. Conclusions Increasing the irradiation distance to 8 mm can have a deleterious influence on mechanical performances, including the FS, DC, and dentin μSBS, of the resin composites polymerized with high-irradiance light curing units.
Collapse
Affiliation(s)
- Soram Oh
- Department of Conservative Dentistry, School of Dentistry, Kyung Hee University, 1 Hoe-gi-dong, Dongdaemoon-gu, Seoul, 02447, Korea
| | - Hyun Ju Kim
- Department of Periodontics, Seoul National University Dental Hospital, 101 Daehakno, Jongno-gu, Seoul, 03080, Korea
| | - Hyun-Jung Kim
- Department of Conservative Dentistry, Kyung Hee University Dental Hospital, 1 Hoe-gi-dong, Dongdaemoon-gu, Seoul, 02447, Korea
| | - Sibel A Antonson
- Department of Oral Science and Translational Research, College of Dental Medicine, Nova Southeastern University, 3200 S. University Dr., Fort Lauderdale, FL, 33328, USA
| | - Sun-Young Kim
- Department of Conservative Dentistry and Dental Research Institute, School of Dentistry, Seoul National University, 101 Daehakno, Jongno-gu, Seoul, 03080, Korea.
| |
Collapse
|
5
|
Effects of aging and light-curing unit type on the volume and internal porosity of bulk-fill resin composite restoration. Saudi Dent J 2022; 34:243-248. [PMID: 35935721 PMCID: PMC9346940 DOI: 10.1016/j.sdentj.2022.01.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Revised: 01/04/2022] [Accepted: 01/12/2022] [Indexed: 11/23/2022] Open
|
6
|
Balhaddad AA, Garcia IM, Maktabi H, Ibrahim MS, Alkhubaizi Q, Strassler H, Collares FM, Melo MAS. Errors in light-emitting diodes positioning when curing bulk fill and incremental composites: impact on properties after aging. Restor Dent Endod 2021; 46:e51. [PMID: 34909415 PMCID: PMC8636082 DOI: 10.5395/rde.2021.46.e51] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Revised: 06/10/2021] [Accepted: 06/15/2021] [Indexed: 11/29/2022] Open
Abstract
Objectives This study aimed to evaluate the effect of improper positioning single-peak and multi-peak lights on color change, microhardness of bottom and top, and surface topography of bulk fill and incremental composites after artificial aging for 1 year. Materials and Methods Bulk fill and incremental composites were cured using multi-peak and single-peak light-emitting diode (LED) following 4 clinical conditions: (1) optimal condition (no angulation or tip displacement), (2) tip-displacement (2 mm), (3) slight tip angulation (α = 20°) and (4) moderate tip angulation (α = 35°). After 1-year of water aging, the specimens were analyzed for color changes (ΔE), Vickers hardness, surface topography (Ra, Rt, and Rv), and scanning electron microscopy. Results For samples cured by single-peak LED, the improper positioning significantly increases the color change compared to the optimal position regardless of the type of composite (p < 0.001). For multi-peak LED, the type of resin composite and the curing condition displayed a significant effect on ΔE (p < 0.001). For both LEDs, the Vickers hardness and bottom/top ratio of Vickers hardness were affected by the type of composite and the curing condition (p < 0.01). Conclusions The bulk fill composite presented greater resistance to wear, higher color stability, and better microhardness than the incremental composite when subjected to improper curing. The multi-peak LED improves curing under improper conditions compared to single-peak LED. Prevention of errors when curing composites requires the attention of all personnel involved in the patient's care once the clinical relevance of the appropriate polymerization reflects on reliable long-term outcomes.
Collapse
Affiliation(s)
- Abdulrahman A Balhaddad
- Ph.D Program Dental Biomedical Sciences, University of Maryland School of Dentistry, Baltimore, MD, USA
| | - Isadora M Garcia
- Ph.D Program Dental Biomedical Sciences, University of Maryland School of Dentistry, Baltimore, MD, USA
| | - Haifa Maktabi
- Division of Operative Dentistry, Department of General Dentistry, University of Maryland School of Dentistry, Baltimore, MD, USA
| | - Maria Salem Ibrahim
- Ph.D Program Dental Biomedical Sciences, University of Maryland School of Dentistry, Baltimore, MD, USA
| | - Qoot Alkhubaizi
- Advanced Education in General Dentistry Division, Department of General Dentistry, University of Maryland School of Dentistry, Baltimore, MD, USA
| | - Howard Strassler
- Division of Operative Dentistry, Department of General Dentistry, University of Maryland School of Dentistry, Baltimore, MD, USA
| | - Fabrício M Collares
- Department of Dental Materials, School of Dentistry, Federal University of Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Mary Anne S Melo
- Ph.D Program Dental Biomedical Sciences, University of Maryland School of Dentistry, Baltimore, MD, USA.,Division of Operative Dentistry, Department of General Dentistry, University of Maryland School of Dentistry, Baltimore, MD, USA
| |
Collapse
|
7
|
Cardoso IO, Machado AC, Fernandes LDO, Soares PV, Raposo LHA. Influence of Tip Diameter and Light Spectrum of Curing Units on the Properties of Bulk-Fill Resin Composites. Eur J Dent 2021; 16:360-366. [PMID: 34905778 PMCID: PMC9339921 DOI: 10.1055/s-0041-1735799] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Abstract
Objective
The aim of this study was to evaluate the influence of different light-curing units (LCUs) with distinct tip diameters and light spectra for activating bulk-fill resins.
Materials and Methods
The specimens (
n
= 10) were made from a conventional composite (Amaris, VOCO) and bulk-fill resins (Aura Bulk Fill, SDI; Filtek One, 3M ESPE; Tetric Bulk Fill, Ivoclar Vivadent) with two diameters, 7 or 10 mm, × 2 mm thickness. Following 24 hours of specimen preparation, the degree of conversion (DC) was evaluated using the Fourier-transform infrared unit. Knoop hardness (KHN) readings were performed on the center and periphery of the specimens. Data were assessed for homoscedasticity and submitted to one-way and three-way analysis of variance followed by the Tukey's and Dunnett's tests, depending on the analysis performed (α = 0.05).
Results
LCUs and specimen diameter significantly affected the DC. The
Tetric Bulk Fill
provided increased DC results when light-cured with
Valo
(54.8 and 53.5%, for 7 and 10 mm, respectively) compared with
Radii Xpert
(52.1 and 52.9%, for 7 and 10 mm, respectively). No significant differences in KHN results were noted for the conventional resin composite (
Amaris
) compared with LCUs (
p
= 0.213) or disc diameters (
p
= 0.587), but the center of the specimen exhibited superior KHN (
p
≤ 0.001) than the periphery.
Conclusion
The light spectrum of the multipeak LCU (
Valo
) significantly increased the DC and KHN of the bulk-fill resin composite with additional initiator to camphorquinone (
Tetric Bulk Fill
) compared with the monowave LCU (
Radii Xpert
). The tip size of the LCUs influenced the performance of some of the resin composites tested.
Collapse
Affiliation(s)
- Igor Oliveiros Cardoso
- Department of Occlusion, Fixed Prosthodontics and Dental Materials, School of Dentistry, Federal University of Uberlândia, Uberlândia, Brazil
| | | | - Luísa de Oliveira Fernandes
- Department of Occlusion, Fixed Prosthodontics and Dental Materials, School of Dentistry, Federal University of Uberlândia, Uberlândia, Brazil
| | - Paulo Vinícius Soares
- Department of Operative Dentistry and Dental Materials, School of Dentistry, Federal University of Uberlândia, Uberlândia, Brazil
| | - Luís Henrique Araújo Raposo
- Department of Occlusion, Fixed Prosthodontics and Dental Materials, School of Dentistry, Federal University of Uberlândia, Uberlândia, Brazil
| |
Collapse
|
8
|
Balhaddad AA, Marghalani AA, Raderman MA, Miginsky E, Massey W, Strassler H, Anne Melo M. Hands-on training based on quantifying radiant exposure improves how dental students cure composites: Skill retention at 2-year follow-up. EUROPEAN JOURNAL OF DENTAL EDUCATION : OFFICIAL JOURNAL OF THE ASSOCIATION FOR DENTAL EDUCATION IN EUROPE 2021; 25:582-591. [PMID: 33220151 DOI: 10.1111/eje.12635] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Revised: 11/18/2020] [Accepted: 11/18/2020] [Indexed: 05/27/2023]
Abstract
INTRODUCTION The durability and longevity of composite restoration are much dependent on the accurate delivery of the energy required to polymerise the material. This study aimed to investigate the extent to which undergraduate dental students acquire and retain light-curing skills following hands-on training. MATERIALS AND METHODS Hands-on training comprises faculty tutoring for critical aspects of the light-curing procedure, such as distance and angulation of the light-curing tip. Assessments of the students' ability to deliver a specified radiant exposure to class III and I simulated RBCs using a dental simulator (MARC-PS® ) at three different time points after the training. Data were analysed using repeated measure ANOVA. RESULTS Immediately after the training, students' performance on curing was improved (p < .05). Overall, the radiant exposure increased after training, but the students lost some of the benefits with time. For curing in the anterior section (anterior sensor-class III), the mean radiant exposure values increased by approximately 20% after the training. After 2 years, the values were 15% greater than baseline values. For curing in the posterior section (posterior sensor-class I), the mean radiant exposure values increased by approximately 150% after the training. A significant decrease (p < .05) was observed; however, the radiant exposure values were still 82% greater than the baseline after 2 years. CONCLUSION A hands-on training dedicated to light-curing procedures facilitated acquisition and retention up to a 2-year follow-up of skill on how light cure composite inside the mouth. The training was more relevant for curing in posterior areas, where orientation can significantly impact light-curing. A hands-on training where the radiant exposure can be measure gave objective measurement metrics to guide the curing performance. This approach is an effective means of teaching practical skills to dental students.
Collapse
Affiliation(s)
- Abdulrahman A Balhaddad
- Dental Biomedical Science PhD Program, University of Maryland School of Dentistry, Baltimore, MD, USA
- Department of Restorative Dental Sciences, College of Dentistry, Imam Abdulrahman Bin Faisal University, Dammam, Saudi Arabia
| | - Abdullah A Marghalani
- Department of Preventive Dentistry, Faculty of Dentistry, Um Al-Qura University, Makkah, Saudi Arabia
- Division of Pediatric Dentistry, Department of Orthodontics and Pediatric Dentistry, University of Maryland School of Dentistry, Baltimore, MD, USA
| | - Michael A Raderman
- Division of Operative Dentistry, Department of General Dentistry, University of Maryland School of Dentistry, Baltimore, MD, USA
| | - Elaine Miginsky
- Division of Operative Dentistry, Department of General Dentistry, University of Maryland School of Dentistry, Baltimore, MD, USA
| | - Ward Massey
- Division of Operative Dentistry, Department of General Dentistry, University of Maryland School of Dentistry, Baltimore, MD, USA
| | - Howard Strassler
- Division of Operative Dentistry, Department of General Dentistry, University of Maryland School of Dentistry, Baltimore, MD, USA
| | - Mary Anne Melo
- Dental Biomedical Science PhD Program, University of Maryland School of Dentistry, Baltimore, MD, USA
- Division of Operative Dentistry, Department of General Dentistry, University of Maryland School of Dentistry, Baltimore, MD, USA
| |
Collapse
|
9
|
Improper Light Curing of Bulkfill Composite Drives Surface Changes and Increases S. mutans Biofilm Growth as a Pathway for Higher Risk of Recurrent Caries around Restorations. Dent J (Basel) 2021; 9:dj9080083. [PMID: 34435995 PMCID: PMC8394739 DOI: 10.3390/dj9080083] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Revised: 07/15/2021] [Accepted: 07/26/2021] [Indexed: 01/10/2023] Open
Abstract
How dentists cure a resin-based material has deleterious effects on the material's properties and its interaction with surrounding dental tissues. Biofilm accumulation has been implicated in the pathogenesis of carious lesions around dental restorations, with its composition manifesting expressed dysbiosis in patients suffering from dental caries. To evaluate the influence of varying radiant exposure on the degree of conversion (DC%), Streptococcus mutans biofilm growth, and surface roughness of bulk-fill composites under different light-curing conditions. Two light-curing units (LCU) at 600 and 1000 mW/cm2 were used to simulate curing conditions with different angulations (∢20° and ∢35°) or 2 mm-distance displacements of the LCU tip. The radiant exposure (RE) was assessed, and the composites were analyzed for DC%. Biofilm formation was induced over the bulk-fill composites and analyzed via colony-forming units counting and scanning electron microscopy (SEM). The surface roughness was analyzed via a profilometer and SEM after biofilm formation. Curing conditions with different angulation or displacement decreased RE compared to the "optimal condition". The moderately (∢35°) angulated LCU tip and low (600 mW/cm2) radiant emittance significantly reduced the DC% (p < 0.05). The difference in DC% between the top and bottom of the composites ranged from 8 to 11% for 600 mW/cm2 and 10 to 20% for 1000 mW/cm2. Greater S. mutans biofilm and surface changes were found in composites with non-optimal RE delivery (e.g., tip displacement and angulation) (p < 0.05). Inadequate polymerization of bulk-fill composites was associated with more biofilm accumulation and surface topography changes. Overall, non-optimally performed curing procedures reduced the amount of delivered RE, which led to low DC%, more biofilm formation, and higher surface roughness. The improper light-curing of bulk-fill composites compromises their physicochemical and biological properties, which could lead to inferior clinical performance and reduced restorative treatments' longevity.
Collapse
|
10
|
Al-Zain AO, Al-Osaimi TM. Effectiveness of Using an Instructional Video in Teaching Light-Curing Technique. ADVANCES IN MEDICAL EDUCATION AND PRACTICE 2021; 12:289-302. [PMID: 33824613 PMCID: PMC8018569 DOI: 10.2147/amep.s298556] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Accepted: 03/05/2021] [Indexed: 05/14/2023]
Abstract
PURPOSE To investigate dental students' ability to deliver satisfactory amounts of irradiance and radiant exposure to simulated cavities by teaching the light-curing technique using instructional video compared to verbal instructions. METHODS Students attended the didactic light-curing lecture explaining the light-curing technique. Participants were divided into two groups (n=60). Each participant light-cured a class III and a class I simulated cavities with sensors built-in a Managing Accurate Resin Curing-Patient Simulator (MARC-PS) system, using a multiple-emission-peak light-emitting-diode unit. Each student either 1) watched an instructional video (V) showing the light-curing technique, or 2) received individual verbal instruction (I). The light-curing performance, in terms of the mean irradiance and radiant exposure, was recorded. Each student performed light-curing again on the simulated cavities. Students' feedback for the corresponding teaching method was collected. Comparisons between before and after each instructional method were analyzed using the Wilcoxon signed-rank test. Comparisons between both instructional methods were analyzed using a Mann-Whitney U-test (α=0.05). RESULTS The students' light-curing performance improved after both methods, as observed on the MARC-PS laptop monitor. The mean irradiance values were anterior-V=1280.6 (183.2), anterior-I=1318.0 (143.5), posterior-V=1337.5 (181.1), posterior-I=1317.6 (248.2) mW/cm2. The mean radiant exposure values were for anterior-V=13.5 (2.7), anterior-I=13.3 (1.6), posterior-V=13.7 (1.9), posterior-I=13.7 (2.5) J/cm2. No significant difference was found between both instruction methods. Students reported that each method was effective. CONCLUSION Using V was comparable to I and an effective tool for teaching the light-curing technique per the students' ability to deliver sufficient amounts of irradiance and radiant exposure to simulated cavities.
Collapse
Affiliation(s)
- Afnan O Al-Zain
- Restorative Dentistry Department, Faculty of Dentistry, King Abdulaziz University, Jeddah, Saudi Arabia
- Correspondence: Afnan O Al-Zain Restorative Dentistry Department, King Abdulaziz University Faculty of Dentistry, P.O. Box 80209, Jeddah, 21589, Saudi ArabiaTel +966539116467Fax +9666403316 Email
| | - Tasneem M Al-Osaimi
- Restorative Dentistry Department, Faculty of Dentistry, King Abdulaziz University, Jeddah, Saudi Arabia
| |
Collapse
|
11
|
Al-Zain AO, Al-Ghamdi ZA, Basahal MM, Al-Bukhary RM, Münchow E. Performance of Multiple Light-curing Units used by Dental Students. Open Dent J 2020. [DOI: 10.2174/1874210602014010671] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Aim:
To investigate the performance of multiple Light-curing Units (LCUs) of different manufacturers used in a dental student clinical setting.
Background:
Manufacturers claim that the irradiance values of the LCUs stay stable over time. However, this may not be accurate among the different units.
Objective:
This study investigated the performance in terms of the irradiance, radiant exposure, and DOC of multiple LCUs of different types used in a dental student clinical setting.
Methods:
Four different LCU were investigated (n=5 units/LCU manufacturer): three Light-Emitting-Diodes (LED) units (Demi Ultra, Mini LED, and E-Morlit) and one quartz-tungsten-halogen (QTH) (PolyluxII). Irradiance and radiant exposure were collected [Managing Accurate Resin Curing-Patient Simulator (MARC-PS)](n=5 readings/unit/tooth). Depth of Cure (DOC) was performed (ISO 4049:2009standards) using a micro-hybrid composite (n=5/unit). Data were analyzed using Kruskal-Wallis and ANOVA followed by Student-Newman-Keuls and Tukey post hoc methods, respectively (α=0.05).
Results:
Using the MARC-PS anterior and posterior teeth sensors, respectively, the mean irradiance for Demi Ultra was (1625.7±38.8) and (1250.4±25.2); Mini LED (1381.1±37.8) and (1058.1±27.3); E-Morlit (1831.1±294.7) and (1545.2±176.0); and Polylux II (932.4±368.5) and (840.4±353.4)mW/cm2. The radiant exposure range was 16-38 J/cm2 for all LCUs. LCUs’ mean DOC ranged from 2.9 to 3.1 mm. Significant differences in irradiance and radiant exposure values were detected among the multiple units and manufacturers. Significant differences in DOC values among the Demi Ultra and Polylux II units were detected. DOC met the standards except for onePolylux II unit.
Conclusion:
The irradiance and radiant exposure values were not the same among the different units, regardless of the manufacturers’ claim of the irradiance values stability over time. Polymerization was not compromised except for one QTH unit per the DOC measurements. Itis highly recommended to closely monitor LCUs used in dental student clinical areas due to the high demand in this type of setting.
Collapse
|
12
|
Effect of the addition of functionalized TiO 2 nanotubes and nanoparticles on properties of experimental resin composites. Dent Mater 2020; 36:1544-1556. [PMID: 33012518 DOI: 10.1016/j.dental.2020.09.013] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2020] [Revised: 06/29/2020] [Accepted: 09/10/2020] [Indexed: 12/14/2022]
Abstract
OBJECTIVE To evaluate the influence of the addition of functionalized and non-functionalized TiO2 nanostructures on properties of a resin composite. METHODS TiO2 nanostructures were synthesized and functionalized, using 3-(aminopropyl)triethoxysilane (APTMS) and 3-(trimethoxysilyl)propyl methacrylate (TSMPM). Characterizations were performed with XRD, EDS, TEM, and TGA. Resin composites containing Bis-GMA/TEGDMA, CQ, DABE, and barium-aluminum silicate glass were produced according to TiO2 nanostructure (nanotube or nanoparticle), concentration (0.3 or 0.9 wt%), and functionalization (APTMS or TSMPM). The resin composite without nanostructures was used as control. The amount of fillers was kept constant at 78.3 wt% for all materials. The degree of conversion (DC - at 0 h and 24 h), maximum polymerization rate (Rpmax), and Knoop microhardness (KHN before and after ethanol softening) were evaluated. Data were analyzed with two-way ANOVA with repeated measures and Tukey's HSD (α = 0.05). RESULTS TGA results demonstrated that functionalizations were effective for both nanostructures. For DC, resin composites, time and interaction effect were significant (p < 0.001). Higher DC was found for 0.3-wt%-functionalized-nanotubes at 24 h. For nanoparticles, only 0.9-wt%-non-functionalized and 0.3-wt%-APTMS-functionalized showed DC similar to the control and all other groups showed higher DC (p < 0.05). Rpmax was higher for 0.3-wt%-APTMS-nanotubes, which corresponded to higher DC after 24 h. The lowest Rpmax occurred for 0.9-wt%-TSMPM-nanotubes, which showed smaller DC at 0 h. For KHN, resin composites, ethanol softening and interaction effect were significant (p < 0.001). KHN decreased after ethanol softening all groups, except for 0.3-wt%-TSMPM-nanotubes, 0.9-wt%-TSMPM-nanotubes, and 0.3-wt%-non-functionalized-nanoparticles. CONCLUSION The resin with 0.3-wt%-TSMPM-nanotubes showed higher DC after 24 h, while being the most stable material after the ethanol softening. SIGNIFICANCE The addition of functionalized TiO2 nanostructures in resin-based materials may improve the properties of the material.
Collapse
|
13
|
Al-Zain AO, Platt JA. Effect of light-curing distance and curing time on composite microflexural strength. Dent Mater J 2020; 40:202-208. [PMID: 32999258 DOI: 10.4012/dmj.2020-002] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
This study investigated the influence of curing distance on µ-flexural strength (µ-FS) of a nano-hybrid composite, cured using the manufacturer-recommended curing time (MCT), compared to a consistent radiant exposure (CRE) using three different light-curing units (LCUs). Beams (6×2×1 mm) were cured using the MCT or CRE with a quartz-tungsten-halogen (QTH); a single-emission-peak light-emitting-diode (SLED), or a multiple-emission-peak light-emitting-diode (MLED) LCU. Specimens were cured at 0-, 2- or 8-mm distances (n=10) and the bottom irradiance and CRE were measured using a Managing Accurate Resin Curing-Resin Calibrator spectrometer. µ-FS testing was performed, and data analyzed using two-way ANOVA and Tukey multiple comparison tests (α=0.05). Mean bottom irradiance was (25.4-99.7 mW/cm2) and CRE (0.31-1.11 J/cm2). µ-FS was 422.1-516.6 MPa (MCT) and 440.4-490.4 MPa (CRE). Comparing CRE to MCT showed that µ-FS significantly decreased using the CRE at 2-mm (QTH) or the MCT at 2- and 8-mm (SLED). µ-FS may be significantly impacted by the curing protocol.
Collapse
Affiliation(s)
- Afnan O Al-Zain
- Operative and Esthetic Dentistry Division, Restorative Dentistry Department, Faculty of Dentistry, King Abdulaziz University
| | - Jeffrey A Platt
- Department of Biomedical Sciences and Comprehensive Care, Indiana University School of Dentistry, Indiana University Purdue University Indianapolis
| |
Collapse
|
14
|
Misinterpretation of ISO 4049 standard recommendations: Impact on Young's modulus and conversion degree of dental composites. J Mech Behav Biomed Mater 2020; 110:103947. [DOI: 10.1016/j.jmbbm.2020.103947] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2020] [Revised: 06/16/2020] [Accepted: 06/21/2020] [Indexed: 11/19/2022]
|
15
|
Al-Zain AO, Marghalani HY. Influence of Light-curing Distances on Microflexural Strength of Two Resin-based Composites. Oper Dent 2020; 45:297-305. [DOI: 10.2341/19-001-l] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
SUMMARY
Objective:
Our objective was to investigate the influence of different curing distances on microflexural strength and the microflexural modulus of two resin-based composites.
Methods:
Two nanohybrid composites were used; Filtek Z250 (Z250) and Tetric EvoCeram (TEC). Rectangular specimens were prepared (2-mm wide × 1-mm deep × 6-mm long) light cured according to the manufacturer's instructions at 0-mm, 2-mm, and 8-mm distances (n=10) and were stored wet at 37°C for 24 hours. A microflexural strength test was performed using a universal testing machine at a crosshead speed of 1 mm/min. The microflexural strength and microflexural modulus data were analyzed using a two-way analysis of variance followed by a Tukey multiple comparison post hoc test (α=0.05).
Results:
The TEC composite had a significantly higher microflexural strength at an 8-mm distance compared with the 0-mm distance. The Z250 composite expressed significantly higher microflexural strength, at 2-mm and 8-mm compared with the 0-mm distance. TEC showed a significantly higher microflexural modulus at an 8-mm distance compared with the 0-mm and 2-mm distances. Z250 also exhibited a significantly higher microflexural modulus at the 2-mm distance, compared with the 8-mm distance. In total, Z250 presented a significantly higher microflexural strength and modulus compared with TEC.
Conclusion:
Curing the explored composites at 2-mm or 8-mm distances from the specimen surface did not have a significant influence on microflexural strength but did significantly affect the microflexural modulus.
Collapse
Affiliation(s)
- AO Al-Zain
- Afnan O Al-Zain, BDS, MSD, PhD, Diploma of Professional Development in Teaching and Learning, Operative and Esthetic Dentistry Division, Restorative Dentistry Department, Faculty of Dentistry, King Abdulaziz University, Jeddah, Saudi Arabia
| | - HY Marghalani
- Hanadi Y Marghalani, BDS, MSc, PhD, DRBBA-Research Group, Operative and Esthetic Dentistry Division, Restorative Dentistry Department, Faculty of Dentistry, King Abdulaziz University, Jeddah, Saudi Arabia
| |
Collapse
|