1
|
Ñaupari-Villasante R, de Freitas A, Hass V, Matos TP, Parreiras SO, Reis A, Gutiérrez MF, Loguercio AD. Prolonged polymerization of a universal adhesive in non-carious cervical lesions: 36-month double-blind randomized clinical trial. J Dent 2024; 142:104823. [PMID: 38145806 DOI: 10.1016/j.jdent.2023.104823] [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: 11/04/2023] [Revised: 12/18/2023] [Accepted: 12/22/2023] [Indexed: 12/27/2023] Open
Abstract
OBJECTIVE To evaluate the effect of prolonged (P) polymerization time of a universal adhesive system applied in etch-and-rinse (ER) or self-etch (SE) strategies on the clinical performance of restorations in non-carious cervical lesions (NCCLs), after 36 months of clinical service. METHODS A total of 140 restorations were randomly placed in 35 subjects according to the polymerization time groups: ER (10 s); ER-P (40 s); SE (10 s); and SE-P (40 s) at 1,200 mW/cm2. Composite resin was placed incrementally. The restorations were evaluated immediately and after 6, 12, 18, and 36 months using the FDI criteria. Data were analyzed using the Kaplan-Meier survival test for retention loss, and the Kruskal-Wallis' test for secondary outcomes (α = 0.05). RESULTS After 36 months, 19 restorations were lost: ER 6, ER-P 2, SE 9, SE-P 2. The retention rates were 82.3% for ER; 94.1 % for ER-P; 73.5 % for SE; and 94.1 % for SE-P, with a significant difference between ER vs. ER-P and SE vs. SE-P, as well as ER vs. SE-P and ER-P vs. SE (p < 0.0001). Minor defects were observed in 18 restorations for the marginal staining criteria: ER 5, ER-P 2, SE 8, SE-P 3; and in 33 restorations for the marginal adaptation criteria: ER 11, ER-P 4, SE 12, and SE-P 6 (p > 0.05). No restorations showed recurrence of caries or postoperative sensitivity. CONCLUSIONS A prolonged polymerization time of 40 s improves the clinical performance of the universal adhesive for both adhesive strategies evaluated, even after 36 months. CLINICAL SIGNIFICANCE Prolonging the polymerization time of a universal adhesive from 10 to 40 s has been shown to improve its clinical performance when used in NCCLs.
Collapse
Affiliation(s)
- Romina Ñaupari-Villasante
- Department of Restorative Dentistry, School of Dentistry, Ponta Grossa State University, Ponta Grossa, PR, Brazil
| | - André de Freitas
- Department of Restorative Dentistry, School of Dentistry, Ponta Grossa State University, Ponta Grossa, PR, Brazil
| | - Viviane Hass
- School of Dentistry, Oral and Craniofacial Sciences, University of Missouri-Kansas City, Kansas City, MO, USA
| | - Thalita P Matos
- Department of Restorative Dentistry, School of Dentistry, Tuiuti University of Paraná, Curitiba, PR, Brazil
| | - Sibelli O Parreiras
- Department of Restorative Dentistry, State University of Northern Paraná, Jacarezinho, PR, Brazil
| | - Alessandra Reis
- Department of Restorative Dentistry, School of Dentistry, Ponta Grossa State University, Ponta Grossa, PR, Brazil
| | - Mario F Gutiérrez
- Universidad de los Andes, Chile. Facultad de Odontología, Santiago, Chile; Department of Restorative Dentistry, Faculty of Dentistry, University of Chile, Santiago, Chile.
| | - Alessandro D Loguercio
- Department of Restorative Dentistry, School of Dentistry, Ponta Grossa State University, Ponta Grossa, PR, Brazil
| |
Collapse
|
2
|
Autonomous-Strengthening Adhesive Provides Hydrolysis-Resistance and Enhanced Mechanical Properties in Wet Conditions. Molecules 2022; 27:molecules27175505. [PMID: 36080272 PMCID: PMC9457668 DOI: 10.3390/molecules27175505] [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: 07/23/2022] [Revised: 08/18/2022] [Accepted: 08/24/2022] [Indexed: 11/17/2022] Open
Abstract
The low-viscosity adhesive that is used to bond composite restorative materials to the tooth is readily damaged by acids, enzymes, and oral fluids. Bacteria infiltrate the resulting gaps at the composite/tooth interface, demineralize the tooth, and further erode the adhesive. This paper presents the preparation and characterization of a low-crosslink-density hydrophilic adhesive that capitalizes on sol-gel reactions and free-radical polymerization to resist hydrolysis and provide enhanced mechanical properties in wet environments. Polymerization behavior, water sorption, and leachates were investigated. Dynamic mechanical analyses (DMA) were conducted using water-saturated adhesives to mimic load transfer in wet conditions. Data from all tests were analyzed using appropriate statistical tests (α = 0.05). The degree of conversion was comparable for experimental and control adhesives at 88.3 and 84.3%, respectively. HEMA leachate was significantly lower for the experimental (2.9 wt%) compared to control (7.2 wt%). After 3 days of aqueous aging, the storage and rubbery moduli and the glass transition temperature of the experimental adhesive (57.5MPa, 12.8MPa, and 38.7 °C, respectively) were significantly higher than control (7.4MPa, 4.3 MPa, and 25.9 °C, respectively). The results indicated that the autonomic sol-gel reaction continues in the wet environment, leading to intrinsic reinforcement of the polymer network, improved hydrolytic stability, and enhanced mechanical properties.
Collapse
|
3
|
Perote LCCC, Barcellos DC, Matuda AGN, Campos RP, Rosetti EP, Pucci CR. Influence of chlorhexidine, propolis, pulpal pressure simulation, and aging on dentin bond strength. Microsc Res Tech 2022; 85:3014-3024. [PMID: 35593488 DOI: 10.1002/jemt.24150] [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: 04/07/2021] [Revised: 03/09/2022] [Accepted: 05/01/2022] [Indexed: 11/05/2022]
Abstract
The present study evaluated the bond strength (μTBS) of dentin treated with chlorhexidine and propolis subjected to simulated pulpal pressure (SPP) and thermocycle aging. One hundred and twenty healthy human molars were sectioned to obtain 2 mm of dentin thickness and were divided into two groups (n = 60): SPP (15 cm H2 O) and no SPP (Control group). Dentin surfaces were conditioned with 37% phosphoric acid for 15 s and were divided according to the dentin treatment (n = 20): Control; Chlorhexidine gluconate (0.2% for 30 s) and Propolis (aqueous propolis extract for 30 s). Half of the specimens were submitted to 15,000 thermocycle aging (5 ± 2°C and 55 ± 2°C). The samples were sectioned into beams and submitted to μTBS. Data were analyzed by three-way ANOVA (SPP × Dentin treatment × Thermocycle aging) and the Tukey's tests (p < .001). With regard to the SPP, ANOVA revealed that the Control group (32.98 MPa) had significantly higher values of μTBS when compared to the SPP (29.19 MPa). With regard to Thermocycle aging, no aging (34.05 MPa) had significantly higher values of μTBS when compared to the aging (28.12 MPa). With regard to the dentin treatment, Propolis and Chlorhexidine did not statistically influence the results (p > .05). The SPP and thermocycle aging negatively influenced the bond strength between the dentin and resin; the 0.2% chlorhexidine digluconate and aqueous propolis extract solutions did not interfere in the bond strength between the resin and dentin. The use of chlorhexidine and propolis as a dental treatment may not influence the dentin bond strength, but SPP and thermocycle aging may damage the longitudinal dentin bond strength.
Collapse
Affiliation(s)
| | | | - Amanda Guedes Nogueira Matuda
- Department Restorative Dentistry, Institute of Science and technology, UNESP - Univ Estadual Paulista, São José dos Campos, SP, Brazil
| | - Raquel Pinto Campos
- Department Restorative Dentistry, Institute of Science and technology, UNESP - Univ Estadual Paulista, São José dos Campos, SP, Brazil
| | | | - César Rogério Pucci
- Department Restorative Dentistry, Institute of Science and technology, UNESP - Univ Estadual Paulista, São José dos Campos, SP, Brazil
| |
Collapse
|
4
|
Fehrenbach J, Isolan CP, Münchow EA. Is the presence of 10-MDP associated to higher bonding performance for self-etching adhesive systems? A meta-analysis of in vitro studies. Dent Mater 2021; 37:1463-1485. [PMID: 34456050 DOI: 10.1016/j.dental.2021.08.014] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Revised: 08/16/2021] [Accepted: 08/17/2021] [Indexed: 11/25/2022]
Abstract
OBJECTIVE The purpose of this systematic review and meta-analysis was to analyze the literature on the bond strength of self-etching (SE) adhesives containing 10-MDP or other acidic functional monomers, comparing the bonding performance of both compositions. METHODS This study is registered in PROSPERO (CRD42020175715) and it followed the PRISMA Statement. The literature search was performed in PubMed, Web of Science, SciELO, Scopus, LILACS, IBECS, and BBO from the starting coverage date through 30 June 2021. Study eligibility criteria consisted of in vitro studies that evaluated the bond strength (microtensile, microshear, tensile or shear testing) to sound dentin/enamel of a minimum of two distinct SE systems, with at least one material containing 10-MDP and one other being comprised of a distinct acidic composition. Statistical analyses were carried out with RevMan 5.3.5 and using random-effects models with the significance level at p < 0.05. Also, Bayesian network meta-analysis (NMA) was conducted using MetaInsight V3 tool. RESULTS From 740 relevant studies evaluated in full-text analysis, 210 were incorporated to the systematic review and 206 in meta-analysis. The majority of studies was classified as having medium risk of bias (56.7%), followed by low (35.2%) and high (8.1%) risk of bias. Data from a total of 64 adhesive systems were collected, which favored the 10-MDP-based group at both dentin (overall effect: 6.98; 95% CI: 5.61, 8.36; p < 0.00001) and enamel (overall effect: 2.79; 95% CI: 1.62, 3.96; p < 0.00001) substrates. Microtensile testing was more frequently used (73.4%) in the included studies. Adhesives based on 10-MDP showed greater bonding performance than adhesives comprised of monomers such as PENTA, 6-MHP, 4-META, 4-MET, pyrophosphate esters, mixed composition or monomers derived from sulfonic acid (p ≤ 0.01); whereas similar bond strength values were verified between 10-MDP-based materials and those containing PEM-F, acrylamide phosphates, 4-AET, MAC-10, or monomers derived from polyacrylic and phosphonic acids (p ≥ 0.05). Adhesives based on GPDM were the only ones that resulted in greater bonding potential than the 10-MDP-based group (p = 0.03). Dental bonds in dentin were favored with the application of 2-step 10-MDP-based adhesives; whereas in enamel the dental bonds were favored for both 2-steps versions of adhesives, regardless of the presence of 10-MDP. Indirect evidence from NMA revealed that 1-step 10-MDP-free and universal 10-MDP-free adhesives seemed to perform worst in dentin and enamel, respectively. SIGNIFICANCE Adhesives containing 10-MDP showed higher bonding performance than materials formulated with other acidic ingredients, although this result relied on the type of mechanical testing, type of the substrate, acidic composition of the adhesive, and the application category of the SE system. This review summarized the effects of the foregoing factors on the adhesion to dental substrates.
Collapse
Affiliation(s)
- Julia Fehrenbach
- Graduate Program in Dentistry, School of Dentistry, Federal University of Rio Grande do Sul, Rua Ramiro Barcelos, 2492, Santa Cecília, Porto Alegre, Brazil.
| | - Cristina Pereira Isolan
- Department of Restorative Dentistry, School of Dentistry, Federal University of Jequitinhonha and Mucuri Valleys, Rua da Glória, 187, Centro, Diamantina, Brazil.
| | - Eliseu Aldrighi Münchow
- Graduate Program in Dentistry, School of Dentistry, Federal University of Rio Grande do Sul, Rua Ramiro Barcelos, 2492, Santa Cecília, Porto Alegre, Brazil; Department of Conservative Dentistry, School of Dentistry, Federal University of Rio Grande do Sul, Rua Ramiro Barcelos, 2492, Porto Alegre, Brazil.
| |
Collapse
|
5
|
Dwiandhany WS, Abdou A, Tichy A, Yonekura K, Ikeda M, Hosaka K, Tagami J, Nakajima M. Additive effects of touch-activated polymerization and extended irradiation time on bonding of light-activated adhesives to root canal dentin. J Prosthet Dent 2021; 127:750-758. [PMID: 33431177 DOI: 10.1016/j.prosdent.2020.11.021] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Revised: 11/07/2020] [Accepted: 11/09/2020] [Indexed: 11/30/2022]
Abstract
STATEMENT OF PROBLEM The bonding of light-activated adhesives to root canal dentin with an additional touch-polymerization activator has been insufficiently examined. PURPOSE The purpose of this in vitro study was to investigate the effect of touch-polymerization activators and extended light-irradiation time on the microtensile bond strength (μTBS) of light-activated adhesives. MATERIAL AND METHODS Post cavities were prepared in 50 extracted mandibular premolars and bonded using Prime&Bond Universal (PBU); PBU+Self Cure Activator (SCA); Clearfil SE Bond 2 (SEB); SEB+Clearfil DC Activator (DCA); or Clearfil Universal Bond Quick ER (UBQ). After light-irradiation for 10 or 20 seconds, the post cavities were filled with dual-activated resin core materials. Eight beams were prepared per specimen and subjected to the μTBS test. The μTBS data were analyzed by using 3-way ANOVAs with the Bonferroni correction (α=.05). RESULTS The 3-way ANOVAs indicated that the use of touch-polymerization activators (SCA and DCA) significantly increased the μTBS of PBU and SEB in both the coronal (P=.015) and apical (P=.001) regions. The extension of light-irradiation time to 20 seconds significantly improved their μTBS in the apical region (P<.001), but not in the coronal region (P=.09). Light-irradiation for 20 seconds increased the μTBS of UBQ significantly in the coronal region (P=.014). CONCLUSIONS Touch-polymerization activators improved the bond strength of light-activated adhesives to root canal dentin, especially when combined with an extended light-irradiation time.
Collapse
Affiliation(s)
- Wahyuni S Dwiandhany
- Graduate student, Department of Cariology and Operative Dentistry, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan; Lecturer, Department of Conservative Dentistry, Faculty of Dentistry, Hasanuddin University, Makassar, South Sulawesi, Indonesia
| | - Ahmed Abdou
- Graduate student, Department of Cariology and Operative Dentistry, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan; Lecturer, Biomaterials Department, Faculty of Oral and Dental Medicine, Modern University for Technology and Information, Mokatam, Cairo, Egypt
| | - Antonin Tichy
- Graduate student, Department of Cariology and Operative Dentistry, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan; Graduate student, Institute of Dental Medicine, First Faculty of Medicine of the Charles University and General University Hospital in Prague, Prague, Czech Republic
| | - Kazuhide Yonekura
- Clinical Fellow, Operative Dentistry Clinic, Tokyo Medical and Dental University Dental Hospital, Tokyo, Japan
| | - Masaomi Ikeda
- Senior Lecturer, Department of Oral Prosthetic Engineering, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Keiichi Hosaka
- Assistant Professor, Department of Cariology and Operative Dentistry, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Junji Tagami
- Professor, Department of Cariology and Operative Dentistry, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Masatoshi Nakajima
- Junior Associate Professor, Department of Cariology and Operative Dentistry, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan.
| |
Collapse
|
6
|
Chen KK, Chen JH, Wu JH, Du JK. Influence of commercial adhesive with/without silane on the bond strength of resin-based composite repaired within twenty-four hours. J Dent Sci 2020; 16:877-884. [PMID: 34141101 PMCID: PMC8189866 DOI: 10.1016/j.jds.2020.12.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2020] [Revised: 12/20/2020] [Indexed: 11/29/2022] Open
Abstract
Background/purpose It is not clear whether the ground surface of resin-based composite (RBC) polymerized requires the application of an adhesive with/without a silane to improve bond strength. This study investigated the bond strength of RBC repaired within 24 h via the application of adhesive with/without a silane. Materials and methods Seventy RBC blocks were prepared and assigned to either 0 or 24 h repair stage. Each stage was divided into seven groups: a control group with no surface roughening or applied adhesive, a surface-roughened group with no applied adhesive, two surface-roughened groups treated with a G-aenial Bond adhesive and a BeautiBond Multi adhesive, two surface-roughened groups treated with the previously-mentioned adhesives as well as silane coupling agents, and one group treated with a Single Bond Universal silane-containing adhesive. Microtensile bond strength (μTBS) measurements were performed after the repaired RBC blocks of each group (n = 5) had been immersed in a 37 °C water bath for 24 h. The failure mode of each sample was determined, and the data were analyzed via one-way analysis of variance and Dunnett's test (p = 0.05). Results Regardless of the repair stage, the μTBS values of the adhesive-only and silane-adhesive groups did not differ significantly from those of the control group (p > 0.05). Only the no-adhesive groups exhibited a significantly time-dependent increase in adhesive failure rate. Conclusion Our results suggest that the application of adhesives either with or without silane can significantly increase the bond strength of repairs to RBCs polymerized within 24 h.
Collapse
Affiliation(s)
- Ker-Kong Chen
- School of Dentistry, College of Dental Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan
- Department of Dentistry, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan
| | - Jeng-Huey Chen
- School of Dentistry, College of Dental Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan
- Department of Dentistry, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan
| | - Ju-Hui Wu
- Department of Dentistry, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan
- Department of Oral Hygiene, College of Dental Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Je-Kang Du
- School of Dentistry, College of Dental Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan
- Department of Dentistry, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan
- Corresponding author. School of Dentistry, Kaohsiung Medical University, 100 Shih-Chuan 1st Road, San-Ming District, Kaohsiung, 807, Taiwan. Fax: + 886 7 3121510.
| |
Collapse
|
7
|
Spencer P, Ye Q, Song L, Parthasarathy R, Boone K, Misra A, Tamerler C. Threats to adhesive/dentin interfacial integrity and next generation bio-enabled multifunctional adhesives. J Biomed Mater Res B Appl Biomater 2019; 107:2673-2683. [PMID: 30895695 PMCID: PMC6754319 DOI: 10.1002/jbm.b.34358] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2018] [Revised: 02/07/2019] [Accepted: 02/20/2019] [Indexed: 12/27/2022]
Abstract
Nearly 100 million of the 170 million composite and amalgam restorations placed annually in the United States are replacements for failed restorations. The primary reason both composite and amalgam restorations fail is recurrent decay, for which composite restorations experience a 2.0-3.5-fold increase compared to amalgam. Recurrent decay is a pernicious problem-the standard treatment is replacement of defective composites with larger restorations that will also fail, initiating a cycle of ever-larger restorations that can lead to root canals, and eventually, to tooth loss. Unlike amalgam, composite lacks the inherent capability to seal discrepancies at the restorative material/tooth interface. The low-viscosity adhesive that bonds the composite to the tooth is intended to seal the interface, but the adhesive degrades, which can breach the composite/tooth margin. Bacteria and bacterial by-products such as acids and enzymes infiltrate the marginal gaps and the composite's inability to increase the interfacial pH facilitates cariogenic and aciduric bacterial outgrowth. Together, these characteristics encourage recurrent decay, pulpal damage, and composite failure. This review article examines key biological and physicochemical interactions involved in the failure of composite restorations and discusses innovative strategies to mitigate the negative effects of pathogens at the adhesive/dentin interface. © 2019 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B:2466-2475, 2019.
Collapse
Affiliation(s)
- Paulette Spencer
- Institute for Bioengineering Research, School of Engineering, University of Kansas, 1530 W. 15th Street, Lawrence, KS 66045-7609, USA
- Department of Mechanical Engineering, University of Kansas,1530 W. 15th Street, Lawrence, KS 66045-7609, USA
| | - Qiang Ye
- Institute for Bioengineering Research, School of Engineering, University of Kansas, 1530 W. 15th Street, Lawrence, KS 66045-7609, USA
| | - Linyong Song
- Institute for Bioengineering Research, School of Engineering, University of Kansas, 1530 W. 15th Street, Lawrence, KS 66045-7609, USA
| | - Ranganathan Parthasarathy
- Department of Civil Engineering, Tennessee State University, 3500 John A Merritt Blvd, Nashville, TN 37209, USA
| | - Kyle Boone
- Institute for Bioengineering Research, School of Engineering, University of Kansas, 1530 W. 15th Street, Lawrence, KS 66045-7609, USA
| | - Anil Misra
- Institute for Bioengineering Research, School of Engineering, University of Kansas, 1530 W. 15th Street, Lawrence, KS 66045-7609, USA
- Department of Civil Engineering, University of Kansas, 1530 W. 15th Street, Lawrence, KS 66045-7609, USA
| | - Candan Tamerler
- Institute for Bioengineering Research, School of Engineering, University of Kansas, 1530 W. 15th Street, Lawrence, KS 66045-7609, USA
- Department of Mechanical Engineering, University of Kansas,1530 W. 15th Street, Lawrence, KS 66045-7609, USA
| |
Collapse
|
8
|
Song L, Ye Q, Ge X, Misra A, Spencer P. Mimicking nature: Self-strengthening properties in a dental adhesive. Acta Biomater 2016; 35:138-52. [PMID: 26883773 DOI: 10.1016/j.actbio.2016.02.019] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2015] [Revised: 02/10/2016] [Accepted: 02/11/2016] [Indexed: 10/22/2022]
Abstract
Chemical and enzymatic hydrolysis provoke a cascade of events that undermine methacrylate-based adhesives and the bond formed at the tooth/composite interface. Infiltration of noxious agents, e.g. enzymes, bacteria, and so forth, into the spaces created by the defective bond will ultimately lead to failure of the composite restoration. This paper reports a novel, synthetic resin that provides enhanced hydrolytic stability as a result of intrinsic reinforcement of the polymer network. The behavior of this novel resin, which contains γ-methacryloxyproyl trimethoxysilane (MPS) as its Si-based compound, is reminiscent of self-strengthening properties found in nature. The efforts in this paper are focused on two essential aspects: the visible-light irradiation induced (photoacid-induced) sol-gel reaction and the mechanism leading to intrinsic self-strengthening. The FTIR band at 2840cm(-1) corresponding to CH3 symmetric stretch in -Si-O-CH3 was used to evaluate the sol-gel reaction. Results from the real-time FTIR indicated that the newly developed resin showed a limited sol-gel reaction (<5%) during visible-light irradiation, but after 48h dark storage, the reaction was over 65%. The condensation of methoxysilane mainly occurred under wet conditions. The storage moduli and glass transition temperature of the copolymers increased in wet conditions with the increasing MPS content. The cumulative amounts of leached species decreased significantly when the MPS-containing adhesive was used. The results suggest that the polymethacrylate-based network, which formed first as a result of free radical initiated polymerization, retarded the photoacid-induced sol-gel reaction. The sol-gel reaction provided a persistent, intrinsic reinforcement of the polymer network in both neutral and acidic conditions. This behavior led to enhanced mechanical properties of the dental adhesives under conditions that simulate the wet, oral environment. STATEMENT OF SIGNIFICANCE A self-strengthening dental adhesive system was developed through a dual curing process, which involves the free radical photopolymerization followed by slow hydrolysis and condensation (photoacid-induced sol-gel reaction) of alkoxylsilane groups. The concept of "living" photoacid-induced sol-gel reaction with visible-light irradiation was confirmed in the polymer. The sol-gel reaction was retarded by the polymethacrylate network, which was generated first; the network extended the life and retained the activity of silanol groups. The self-strengthening behavior was evaluated by monitoring the mechanical properties of the hybrid copolymers under wet conditions. The present research demonstrates the sol-gel reaction in highly crosslinked network as a potentially powerful strategy to prolong the functional lifetime of engineered biomaterials in wet environments.
Collapse
|
9
|
Genari B, Leitune VCB, Jornada DS, Camassola M, Pohlmann AR, Guterres SS, Samuel SMW, Collares FM. Effect of indomethacin-loaded nanocapsules incorporation in a dentin adhesive resin. Clin Oral Investig 2016; 21:437-446. [PMID: 27068412 DOI: 10.1007/s00784-016-1810-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2015] [Accepted: 03/23/2016] [Indexed: 12/01/2022]
Abstract
OBJECTIVES The aim of this study was to produce indomethacin-loaded nanocapsules (IndOH-NCs) and evaluate the influence of their incorporation into an adhesive resin. MATERIALS AND METHODS Indomethacin was encapsulated by the deposition of preformed polymer. IndOH-NCs were characterized by laser diffractometry, Fourier transformed infrared spectrometry, transmission electron microscopy (TEM), scanning electron microscopy, high-performance liquid chromatography (HPLC), and MTT assay. Nanocapsules (NCs) were incorporated into an adhesive in concentrations of 1, 2, 5, and 10 %. The addition was visualized by TEM and drug release was evaluated by HPLC until 120 h of immersion in simulated body fluid (SBF). Drug diffusion through dentin was tested using a Franz diffusion cell apparatus and quantified by HPLC. The degree of conversion (DC), softening in ethanol, and microtensile bond strength (μTBS) were evaluated to determine whether the nanocapsules influenced the adhesive. Data were analyzed using one-way ANOVA and Tukey's post hoc test for DC, softening in ethanol, μTBS, and cytotoxicity, and paired t test for comparison between the initial and final Knoop microhardness. RESULTS IndOH-NCs, with a spherical shape and a mean diameter of 165 nm, were incorporated into an adhesive. Indomethacin content was 7 mg drug/g powder. IndOH-NCs maintained high cell viability. At 120 h, an amount of 13.83 % of indomethacin was released, and after 7 days, 7.07 % of this drug was diffused through dentin for an adhesive containing 10 % of nanocapsules. No alteration in the DC, softening in ethanol, and μTBS resulted from NC addition. CONCLUSIONS IndOH-NCs may be incorporated into adhesive systems, without compromising properties, to add an anti-inflammatory drug controlled release for restorative procedures in deep cavities. CLINICAL SIGNIFICANCE Here is the first step toward the goal of providing agents to act at an inflammatory process of pulp tissue through dental adhesives via encapsulation of drug.
Collapse
Affiliation(s)
- Bruna Genari
- Dental Materials Laboratory, School of Dentistry, Federal University of Rio Grande do Sul, Ramiro Barcelos Street, Porto Alegre, RS, 2492, Brazil
| | - Vicente Castelo Branco Leitune
- Dental Materials Laboratory, School of Dentistry, Federal University of Rio Grande do Sul, Ramiro Barcelos Street, Porto Alegre, RS, 2492, Brazil
| | | | - Melissa Camassola
- Laboratory of stem cells and tissue engineering, Universidade Luterana do Brazil, Porto Alegre, RS, Brazil
| | - Adriana Raffin Pohlmann
- Pharmaceutical Sciences, Federal University of Rio Grande do Sul, Porto Alegre, RS, Brazil.,Institute of Chemistry, Federal University of Rio Grande do Sul, Porto Alegre, RS, Brazil
| | | | - Susana Maria Werner Samuel
- Dental Materials Laboratory, School of Dentistry, Federal University of Rio Grande do Sul, Ramiro Barcelos Street, Porto Alegre, RS, 2492, Brazil
| | - Fabrício Mezzomo Collares
- Dental Materials Laboratory, School of Dentistry, Federal University of Rio Grande do Sul, Ramiro Barcelos Street, Porto Alegre, RS, 2492, Brazil.
| |
Collapse
|