Relined Fiberglass Post: Effect of Luting Length, Resin Cement, and Cyclic Loading on the Bond to Weakened Root Dentin

SUMMARY This study evaluated the effects of luting length of the post, the resin cement, and cyclic loading on pull-out bond strength of fiberglass posts relined with composite resin in weakened roots. The canals of 80 bovine incisors were endodontically treated and weakened with diamond burs. The teeth were randomly divided into eight groups (n=10) according to the luting procedures of the relined fiberglass post (RFP): In groups 1, 2, 3, and 4, the RFPs were luted with RelyX ARC, and in groups 5, 6, 7, and 8 they were luted with RelyX U200. In groups 1, 3, 5, and 7, the RFPs were luted at a length of 5 mm, and in groups 2, 4, 6, and 8 they were luted at a length of 10 mm. Specimens from groups 3, 4, 7, and 8 were submitted to cyclic loading. Specimens were subjected to a pull-out bond strength test in a universal testing machine. The results (MPa) were analyzed by three-way analysis of variance and the Tukey post hoc test (α=0.05). Six human upper anterior teeth were used to analyze the bond interface by confocal laser scanning microscopy (CLSM). The pull-out bond strength of RFPs luted with RelyX U200 was statistically higher than that of RelyX ARC. Cyclic loading influenced the bond strength only for the luting length of 5 mm. CLSM analysis revealed the formation of resin cement tags for both materials. Luting length is an important factor in retaining RFPs in weakened roots when they are subjected to cyclic loading, and RelyX U200 resulted in greater bond strengths to the root canal in comparison with RelyX ARC.

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Customized Fiber Post Improves the Bond Strength and Dentinal Penetrability of Resin Cementation System to Root Dentin

Operative Dentistry ◽

10.2341/20-117-l ◽

2021 ◽

Author(s):

TP Leandrin ◽

E Fernández ◽

RO Lima ◽

JF Besegato ◽

WG Escalante-Otárola ◽

...

Keyword(s):

Bond Strength ◽

Laser Scanning ◽

Resin Composite ◽

Resin Cement ◽

Laser Scanning Microscopy ◽

Mixed Data ◽

Confocal Laser ◽

Fiber Post ◽

Root Dentin ◽

Post Space

SUMMARY Objective: This study aimed to evaluate the effect of fiber post customization on the bond strength (24 hours and 6 months), resin cement thickness, and dentinal penetrability of Adper Scotchbond Multi-Purpose – RelyX ARC (AS-RA), RelyX U200 (R2), and Scotchbond Universal – RelyX Ultimate (SU-RU) cementation systems to root dentin from the cervical-, middle-, and apical-thirds of the post space. Methods: One hundred twenty bovine incisors were endodontically treated. After post space preparation, the roots were divided into six groups, according to the luting protocols (AS–RA, R2, SU– RU) and the type of fiber post [noncustomized post (NC) and customized post (C)]. Customization procedures were peformed using a resin composite (Z350 XT). 24 hours (n=60) or 6 months later (n=60), specimens from the cervical-, middle-, and apical-thirds of the post space were submitted to cementation system thickness measurement, bond strength evaluation, and dentinal penetrability analysis with Confocal Laser Scanning Microscopy (CLSM). Failure mode was classified as adhesive, cohesive, or mixed. Data were submitted to ANOVA and Tukey tests (α=0.05). Results: Cementation protocols with customized fiber posts presented the lowest cementation system thickness, regardless of the cementation system or post space-third (p<0.05), and the highest bond strength values (p<0.05), regardless of the third space (p>0.05), for both periods (24 hours or 6 months). The comparison of push-out bond strength values between 24 hours and 6 months showed a reduction in all groups for the cervical-third (p<0.05). For the middle-third, only noncustomized groups showed reduction (p<0.05). For the apical-third, no reduction was observed (p>0.05). Conclusions: Anatomical customization favored both the bond strength of cements to dentin and the dentinal penetrability, but with lower cementation system thickness, regardless of cement composition and adhesive strategy.

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Evaluation of Degree of Conversion, Resin-Dentin Bond Strength, and Durability of Polydopamine Incorporated Total Etch Adhesive System

Frontiers in Dentistry ◽

10.18502/fid.v17i35.5199 ◽

2021 ◽

Author(s):

Vandana James ◽

Manavalan Madhana Madhubala ◽

Shari S Devarajan ◽

Sekar Mahalaxmi ◽

Shanmugasundaram Sathyakumar

Keyword(s):

Bond Strength ◽

Laser Scanning ◽

Testing Machine ◽

Adhesive System ◽

Degree Of Conversion ◽

Laser Scanning Microscopy ◽

Confocal Laser ◽

Occlusal Surfaces ◽

Bonferroni Test ◽

Strength And Durability

Objectives: This study aimed to evaluate the degree of conversion (DC%), shear bond strength (SBS), bond durability, and the resin-dentin interface of polydopamine (PDA) incorporated total-etch adhesive system. Materials and Methods: Five percentage by weight (wt%) concentration of PDA incorporated adhesive was prepared and its polymerization was evaluated using Fourier-transform infrared spectroscopy. The results were compared with the DC% of conventional total-etch adhesive (Adper Single Bond 2) using independent t-test. Occlusal surfaces of 80 freshly extracted human premolars were sectioned to expose the dentin, which was acid-etched. The samples were divided into two groups (n=40) of total-etch adhesive and total-etch adhesive+PDA. Composite resin blocks were built up over the bonded surface and cured. Each group was subdivided into two subgroups (n=20) of immediate and post-aging evaluation. Samples were immersed in 10% sodium hypochlorite for five hours, and then, the SBS was evaluated using a universal testing machine at a crosshead speed of 1 mm/minute. The resin-dentin interface was evaluated using confocal laser scanning microscopy. Data were analyzed using two-way analysis of variance and post-hoc Bonferroni test. Results: DC% was not affected by the addition of 5% PDA to the adhesive (group 2). The SBS of group 2A was significantly higher than that of group 1A. There was no significant reduction of SBS in group 2B. The hybrid layer was less degraded after aging in group 2B compared to group 2A. Conclusions: PDA incorporated adhesive increased the immediate bond strength and durability without changing the DC%.

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Micromorphological analysis and bond strength comparison of two adhesives for different degrees of dental fluorosis

10.21203/rs.3.rs-16637/v3 ◽

2020 ◽

Author(s):

Shuangfeng Liu ◽

Yanxia Zhu ◽

Tana Gegen

Keyword(s):

Shear Strength ◽

Bond Strength ◽

Bonding Strength ◽

Laser Scanning ◽

Dental Fluorosis ◽

Laser Scanning Microscopy ◽

Confocal Laser ◽

Cohesive Failure ◽

Bonding System ◽

Significant Difference

Abstract The objective of this study was to analyze morphologically the all-etching bonding system and self-etching bonding system for enamel with different degrees of fluorosis and evaluate the bond strength of each system. Teeth that were indicated for extraction owing to orthodontic or periodontal problems were selected. According to Dean’s index and the Thylstrup-Fejerskov index, 180 extracted teeth were divided into three groups of mild, moderate, and severe dental fluorosis (DF), with 60 teeth in each group. The teeth in each group were randomly divided into two subgroups (n = 30), which were then subjected to the all-etching bonding system (Prime & Bond NT) and self-etching bonding system (SE-Bond). Each group of adhesives was used to bond Z350 universal resin (3M) to the etched dental enamel. Tensile and shear tests were conducted to determine the bond strength. Subsequently, the fractured specimens were investigated using scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM). The Prime & Bond NT was statistically significant for the tensile and shear strength of enamel with mild fluorosis (P < 0.05) but did not exhibit a significant difference for moderate and severe DF (P > 0.05). The SE-Bond was not statistically significant for the tensile and shear strength of mild, moderate, or severe DF (P > 0.05). The SEM and CLSM results reveal that the mild fluorosis enamel crystals were relatively dense, and a small amount of resin remained. The moderate fluorosis enamel crystals were loosely arranged, and the gaps were widened. The severe fluorosis enamel crystals were irregularly arranged. The disorder was aggravated, and the dentinal orifice was exposed by partial enamel exfoliation. The bonding strength of mild fluorosis enamel with the Prime & Bond NT was better than that with the SE-Bond, and cohesive failure was the most common mode of failure. Because there was no difference in the bonding strength of the SE-Bond for different degrees of DF, we recommend the use of the all-etching adhesive system in the clinical treatment of teeth with mild fluorosis.

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Triacrylamide-Based Adhesives Stabilize Bonds in Physiologic Conditions

Journal of Dental Research ◽

10.1177/00220345211061736 ◽

2022 ◽

pp. 002203452110617

Author(s):

F.S. de Lucena ◽

S.H. Lewis ◽

A.P.P. Fugolin ◽

A.Y. Furuse ◽

J.L. Ferracane ◽

...

Keyword(s):

Bond Strength ◽

Cross Sections ◽

Laser Scanning ◽

Adhesive System ◽

Laser Scanning Microscopy ◽

Confocal Laser ◽

Gap Formation ◽

Bond Stability ◽

Occlusal Surfaces ◽

Before And After

In this study, an acrylamide-based adhesive was combined with a thiourethane-based composite to improve bond stability and reduce polymerization stress, respectively, of simulated composite restorations. The stability testing was conducted under physiologic conditions, combining mechanical and bacterial challenges. Urethane dimethacrylate was combined with a newly synthesized triacrylamide (TMAAEA) or HEMA (2-hydroxyethyl-methacrylate; control) to produce a 2-step total-etch adhesive system. Methacrylate-based composites (70 wt% silanized filler) were formulated, containing thiourethane oligomers at 0 (control) or 20 wt%. Standardized preparations in human third molars were restored; then, epoxy replicas were obtained from the occlusal surfaces before and after 7-d storage in water or with Streptococcus mutans biofilm, which was tested after storage in an incubator (static) or the bioreactor (mechanical challenge). Images were obtained from the replicas (scanning electron microscopy) and cross sections of the samples (confocal laser scanning microscopy) and then analyzed to obtain measurements of gap, bacterial infiltration, and demineralization. Microtensile bond strength of specimens stored in water or biofilm was assessed in 1-mm2 stick specimens. Data were analyzed with analysis of variance and Tukey’s test (α = 0.05). HEMA-based materials had greater initial gap measurements, indicating more efficient bonding for the acrylamide materials. When tested in water, the triacrylamide-based adhesive had smaller gaps in the incubator or bioreactor. In the presence of biofilm, there was less difference among materials, but the acrylamide/thiourethane combination led to statistically lower gap formation in the bioreactor. HEMA and TMAAEA-based adhesives produced statistically similar microtensile bond strengths after being stored in water for 7 d, but after the same period with biofilm-challenged specimens, the TMAAEA-based adhesives were the only ones to retain the initial bond strength values. The use of a stable multiacrylamide-based adhesive led to the preservation of the resin-dentin bonded interface after a physiologically relevant challenge. Future studies will include a multispecies biofilm model.

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Analysis of Shear Bond Strength and Morphology of Er:YAG Laser-Recycled Ceramic Orthodontic Brackets

BioMed Research International ◽

10.1155/2016/7276287 ◽

2016 ◽

Vol 2016 ◽

pp. 1-6 ◽

Cited By ~ 1

Author(s):

Ruo-qiao Han ◽

Kai Yang ◽

Ling-fei Ji ◽

Chen Ling

Keyword(s):

Bond Strength ◽

Shear Bond Strength ◽

Laser Scanning ◽

Er:Yag Laser ◽

Statistical Significance ◽

Laser Scanning Microscopy ◽

Confocal Laser ◽

Control Group ◽

Test Machine ◽

Ceramic Brackets

Objective. The aim of this study was to compare the recycling of deboned ceramic brackets via an Er:YAG laser or via the traditional chairside processing methods of flaming and sandblasting; shear bond strength and morphological changes were evaluated in recycled brackets versus new brackets.Materials and Methods. 3M Clarity Self-Ligating Ceramic Brackets with a microcrystalline base were divided into groups subjected to flaming, sandblasting, or exposure to an Er:YAG laser. New ceramic brackets served as a control group. Shear bond strengths were determined with an Electroforce test machine and tested for statistical significance through analysis of variance. Morphological examinations of the recycled ceramic bracket bases were conducted with scanning electron microscopy and confocal laser scanning microscopy. Residue on the bracket base was analyzed with Raman spectroscopy.Results. Faded, dark adhesive was left on recycled bracket bases processed via flaming. Adhesive was thoroughly removed by both sandblasting and exposure to an Er:YAG laser. Compared with new brackets, shear bond strength was lower after sandblasting (p<0.05), but not after exposure to an Er:YAG laser. The Er:YAG laser caused no damage to the bracket.Conclusion. Er:YAG lasers effectively remove adhesive from the bases of ceramic brackets without damaging them; thus, this method may be preferred over other recycling methods.

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Bone Response to Cyclic Loading with Anodized Implants

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.342-343.117 ◽

2007 ◽

Vol 342-343 ◽

pp. 117-120

Author(s):

Byung Uk Lee ◽

Seong Joo Heo ◽

Jai Young Koak ◽

Seong Kyun Kim ◽

Yong Sik Kim ◽

...

Keyword(s):

Cyclic Loading ◽

Anodic Oxidation ◽

Laser Scanning ◽

Laser Scanning Microscopy ◽

Confocal Laser ◽

Machined Surface ◽

Alizarin Red ◽

Bone Response ◽

New Zealand White Rabbits ◽

Oxidation Surface

The purpose of this study was to evaluate the bone interface response to different surface using bone remodeling rate (BRR) under cyclic loading. The tibiae of 10 New Zealand white rabbits were used. Each tibia of rabbits received 2 implants, one with anodic oxidation surface and the other with machined surface. Dynamic loading, a cyclic load of 100 N with 100 cycles was applied for 2 weeks. All implants were divided into 4 groups according to surface treatment and loading; (1) machined surface, unloaded, (2) anodic oxidation surface, unloaded, (3) machined surface, loaded, and (4) anodic oxidation surface, loaded. To determine the rate of bone formation, a series of fluorochrome bone labeling materials (tetracycline, alizarin red, and calcein green) were administrated intramuscularly at 10, 11, 12 weeks. To study the formation time of new bone, ground sections were examined under confocal laser scanning microscopy. Resonance frequency analysis (RFA) values were measured at the time of first surgery, second surgery and sacrifice. From this study, it was concluded that implants with anodic oxidation surface had higher value than machined surface on RFA measurement and anodic oxidation surface has more resistance to loading than machined surface.

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Effect of Etching Procedures on the Adhesion of Biofilm-Coated Dentin

Materials ◽

10.3390/ma13122762 ◽

2020 ◽

Vol 13 (12) ◽

pp. 2762

Author(s):

Bo-Kyung Jeon ◽

Chang-Ha Lee ◽

A Reum Kim ◽

Seung Hyun Han ◽

Hyun-Jung Kim ◽

...

Keyword(s):

Bond Strength ◽

Biofilm Formation ◽

Laser Scanning ◽

Failure Modes ◽

Laser Scanning Microscopy ◽

Confocal Laser ◽

Acid Etching ◽

Dentin Surface ◽

Biofilm Removal ◽

Oral Biofilms

Oral biofilms coat all surfaces in the oral cavity including the exposed dentin surface. This study aimed to investigate biofilm removal by acid etching procedures and the effects of the residual biofilm on dentin surfaces on composite–dentin adhesion. Dentin discs were assigned to five groups: no biofilm formation (C); biofilm formation and no surface treatment (BF); biofilm formation and acid etching (BF-E); biofilm formation and acid etching followed by chlorhexidine soaking (BF-EC); and biofilm formation and rubbing with pumice, followed by acid etching (BF-RE). Biofilms were formed on saliva-precoated dentin discs by soaking the discs in Streptococcus mutans (S. mutans) suspension. Biofilm removal from the dentin surface was evaluated quantitatively and qualitatively by confocal laser scanning microscopy and scanning electron microscopy, respectively. To compare the bond strength of the biofilm-coated dentin discs with the surface treatments, specimens were assigned to four groups: no biofilm formation and acid etching (C-E); BF-E; BF-EC; and BF-RE. Assessments of the micro-shear bond strength and subsequent failure modes were performed. BF-E and BF-EC did not remove the biofilm, whereas BF-RE partially removed the biofilm attached to the dentin (p < 0.05). The bond strength of BF-RE was significantly higher than those of BF-E and BF-EC, but lower than that of C-E (p < 0.05). In conclusion, mechanical biofilm removal is recommended before etching procedures to enhance adhesion to the biofilm-coated dentin.

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Bacterial Colonization in the Marginal Region of Ceramic Restorations: Effects of Different Cement Removal Methods and Polishing

Operative Dentistry ◽

10.2341/15-206-l ◽

2016 ◽

Vol 41 (6) ◽

pp. 642-654 ◽

Cited By ~ 5

Author(s):

SMB Pereira ◽

LC Anami ◽

CA Pereira ◽

ROA Souza ◽

KZ Kantorski ◽

...

Keyword(s):

Laser Scanning ◽

Bacterial Colonization ◽

Resin Cement ◽

Laser Scanning Microscopy ◽

Confocal Laser ◽

Significant Difference ◽

Ceramic Blocks ◽

Cement Removal ◽

Ceramic Restorations ◽

Marginal Region

SUMMARY This study evaluated the effects of excess cement removal techniques, with or without subsequent polishing, on biofilm formation and micromorphology in the marginal region of the tooth/restoration. From bovine teeth, 96 dentin blocks (4 × 8 × 2 mm) were produced, molded, and reproduced in type IV gypsum, on which 96 pressed ceramic blocks (Vita PM9, Vita Zahnfabrik; 4 × 8 × 2 mm) were produced via the lost wax technique. The dentin blocks and their respective ceramic blocks were cemented with a self-adhesive resin cement (RelyX U200, 3M ESPE), and cement excess was removed from the margin using four different techniques, followed or not by polishing with silicone rubber tips: MBr, removal with microbrush and photoactivation; MBr-Pol, MBr + polishing; Br, removal with brush and photoactivation; Br-Pol, Br + polishing; Photo-Expl, 5 seconds of initial photoactivation, removal with explorer, and final curing; Photo-Expl-Pol, Photo-Expl + polishing; Photo-SB, 5 seconds of initial photoactivation, removal with scalpel, and final curing; and Photo-SB-Pol, Photo-SB + polishing. After 24 hours, the roughness in the marginal region was analyzed using a profilometer (three measurements on each sample). Micromorphological analyses of the region were performed by stereomicroscope and scanning electron microscopy (SEM). Then the samples were contaminated with sucrose broth standardized suspension with Streptococcus mutans, Staphylococcus aureus, and Candida albicans and incubated for a period of 48 hours. The samples were quantitatively analyzed for bacterial adherence in the marginal region by confocal laser scanning microscopy and counting of colony-forming units (CFUs/mL) and qualitatively analyzed using SEM. Roughness data (Ra) were submitted to two-way analysis of variance, Tukey test at a confidence level of 95%, and Student t-tests. CFU, biomass, and biothickness data were analyzed by Kruskal-Wallis, Mann-Whitney, and Dunn tests. The removing technique statistically influenced Ra (MBr, p=0.0019; Br, p=0.002; Photo-Expl, p=0.0262; Photo-SB, p=0.0196) when comparing the polished and unpolished groups. The MBr and MBr-Pol technique differed significantly for CFU/mL values (p=0.010). There was no significant difference in the amounts of biomass and biothickness comparing polished and unpolished groups and when all groups were compared (p>0.05). Different morphological patterns were observed (more regular surface for polished groups). We conclude that margin polishing after cementation of feldspar/pressed ceramic restorations is decisive for achieving smoother surfaces, as the excess cement around the edges can increase the surface roughness in these areas, influencing bacterial adhesion.

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Influence of Light-curing Parameters on Biofilm Development and Flexural Strength of a Silorane-based Composite

Operative Dentistry ◽

10.2341/14-279-l ◽

2016 ◽

Vol 41 (2) ◽

pp. 219-227 ◽

Cited By ~ 3

Author(s):

E Brambilla ◽

A Ionescu ◽

G Cazzaniga ◽

M Ottobelli

Keyword(s):

Flexural Strength ◽

Laser Scanning ◽

Testing Machine ◽

Laser Scanning Microscopy ◽

Confocal Laser ◽

Curing Time ◽

Two Samples ◽

Significant Difference ◽

Light Curing ◽

Biofilm Development

SUMMARYObjectives: The aim of this study was to evaluate the differences in biological and mechanical performances of a silorane-based and a methacrylate-based composite. Another aim was to assess the influence of light-curing time and light-curing intensity on in vitro biofilm formation and flexural strength of the two tested composites.Methods: Experiment 1: 432 specimens obtained from a silorane-based composite and from a standard methacrylate-based composite were divided into six groups and light-cured for 10, 20, 30, 40, 60, or 80 seconds, using one of two light-curing intensities, 400 mW/cm2 or 800 mW/cm2. At 24 hours, a monospecific Streptococcus mutans biofilm adherent to the surfaces of the samples was obtained. Then, a colorimetric technique (MTT assay) was used to evaluate the adherent viable biomass. Two samples per group were observed using confocal laser scanning microscopy. Analysis of variance (ANOVA) and Tukey tests were used to analyze the results (p<0.05). Experiment 2: 192 bar-shaped specimens were obtained and light-cured as in the previous experiment. A three-point bend test using a universal testing machine was performed to obtain flexural strength values. ANOVA and Tukey tests were used to analyze the results (p<0.05).Results: In experiment 1, a highly significant difference (p<0.0001) in biofilm development was shown between silorane-based and methacrylate-based composites. In fact, the silorane-based composite exhibited better biological performance. Significant differences were also found between the two light-curing intensities (p<0.018) and for curing times (p<0.0001): silorane-based composite light-cured for 80 seconds at 800 mW/cm2 light-curing intensity showed the lowest biofilm development. In experiment 2, a significant difference in flexural strength (p<0.0318) was only found between the different composites. Nevertheless, both resin composites showed flexural strength values in accordance with International Organization for Standardization guidelines even after 10 seconds of light-curing time.Conclusions: Silorane-based composite was less prone to biofilm development compared with a methacrylate-based composite. Acceptable flexural strength values for both composites were obtained after 10 seconds of light-curing time.

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Correlation between Bond Strength to Dentin and Sealers Penetration by Push-Out Test and CLSM Analysis

Brazilian Dental Journal ◽

10.1590/0103-6440201902766 ◽

2019 ◽

Vol 30 (6) ◽

pp. 555-562

Author(s):

Maybell Tedesco ◽

Marcelo Carvalho Chain ◽

Wilson Tadeu Felippe ◽

Ana Maria Hecke Alves ◽

Lucas da Fonseca Roberti Garcia ◽

...

Keyword(s):

Bond Strength ◽

Laser Scanning ◽

Regional Analysis ◽

Kendall Test ◽

Laser Scanning Microscopy ◽

Confocal Laser ◽

Dentinal Tubules ◽

Significant Difference ◽

Ah Plus ◽

Push Out

Abstract This study correlated the bond strength (BS) and dentin penetration of different sealers by push-out test and Confocal Laser Scanning Microscopy (CLSM) analysis. Forty-five root canals were prepared according to the crown-down technique and filled with gutta-percha associated to the following sealers (n=15): Endofill, AH Plus and MTA Fillapex. Five canals of each group were filled with the sealers added with 0.1% Rhodamine B dye. Next, the specimens were transversely sectioned and submitted to the push-out test (n=10) and CLSM analysis (n=5). The BS data showed the following means (MPa) and standard deviation: AH Plus (4.17±1.86); MTA Fillapex (3.13±1.96) and Endofill (2.10±1.03). Statistical analysis (two-way ANOVA, α=0.05) showed significant difference among sealers (p<0.001) and root canal thirds (p<0.001). The BS results of Endofill and MTA Fillapex were statistically similar (p>0.05), however, they were statistically different from AH Plus (p<0.001). The regional analysis of BS showed similarity between middle and apical thirds (p>0.05), and both were different from coronal portion (p<0.001). CLSM analysis verified tags formation in all groups and higher penetration of the specimens filled with AH Plus (p<0.05). The Kendall test (correlation between BS to dentin and sealer penetration into dentinal tubules) and the Pearson test (between failures pattern and sealer penetration into dentinal tubules) did not show correlation between the variables evaluated for all the tested sealers (p>0.05). AH Plus group had higher BS to dentin, and deeper tags formation than the other sealers. There was no significant correlation between BS and intratubular penetration of the tested sealers.

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