scholarly journals Influence of bleaching and desensitizing gel on bond strength of orthodontic brackets

2015 ◽  
Vol 20 (2) ◽  
pp. 49-54 ◽  
Author(s):  
Fernanda Alves Rodrigues Britto ◽  
Adriana Simoni Lucato ◽  
Heloisa Cristina Valdrighi ◽  
Sílvia Amélia Scudeler Vedovello

OBJECTIVE: The objective of this study was to assess, in vitro, the influence of bleaching gel and the use of desensitizing agent over bond strength of ceramic brackets bonded to bovine enamel. METHODS: One hundred bovine incisors were selected and randomly divided into five groups (n = 20): Group 1, control group (without bleaching); Group 2, bleached with 35% hydrogen peroxide; Group 3, bleached with 35% hydrogen peroxide (three applications, 15 minutes each) and desensitizing agent applied for 10 minutes; Group 4, bleached with 35% hydrogen peroxide for 40 minutes; Group 5, bleached with 35% hydrogen peroxide for 40 minutes with desensitizing agent applied for 10 minutes. Brackets were bonded 7 days after bleaching and submitted to shear bond strength test after 24 hours at a compression rate of 1 mm/minute. After fracture, the adhesive remnant index (ARI) was assessed under stereoscopic at 40 x magnification. Shear strength data (MPa) were submitted to one-way ANOVA and Tukey's test with significance level set at 5%. RESULTS: Group 5 (29.33 MPa) showed significantly higher bond strength than Group 1 (19.19 MPa), Group 2 (20.59 MPa) and Group 4 (23.25 MPa), but with no difference in comparison to Group 3. There was no significant difference among the other groups. The adhesive remnant index showed predominance of score 3, that is, all resin remained adhered to enamel for all groups. CONCLUSION: Bleaching with 35% hydrogen peroxide with calcium associated with desensitizing agent application produced higher bond strength values of brackets bonded to bovine enamel.

2012 ◽  
Vol 3 (2) ◽  
pp. 166-170
Author(s):  
Carla Zogheib ◽  
Etienne Medioni

ABSTRACT Forty-eight extracted maxillary anterior teeth instrumented with ProTaper system to apical preparations 0.25, 0.40 and 0.60 mm (n = 16 each) were divided into six groups for filling as following: Group 1: Apical preparation 25/100 + gutta-percha/AH Plus sealer, group 2: Apical preparation 25/100 + Resilon/Real Seal, group 3: Apical preparation 40/100 + gutta-percha/AH plus sealer, group 4: Apical preparation 40/100 + Resilon/Real Seal, group 5: Apical preparation 60/100 + gutta-percha/AH plus, group 6: Apical preparation 60/100 + Resilon/Real Seal. All teeth were filled using the warm vertical technique. Horizontal sections at 1, 2 and 3 mm from the apex were observed by SEM under 200 × magnification. Sections were digitally photographed under a stereomicroscope and the images were transferred to a compatible PC for image analysis. The surface area of voids were calculated and compared at all levels; using the Kruskal-Wallis test with Sidak correction and Mann-Whitney U test (p > 0.05). Comparisons within each group (gutta-percha/AH plus and Resilon/Real Seal) showed the presence of voids but there was no significant difference between any level of sectioning for apical preparations of 25 and 40 (p > 0.05). The only difference was in the groups prepared to size 60 and filled with Resilon/ Real Seal which showed significantly more voids than the group filled with gutta-percha/AH plus and especially at the 3 mm level. Conclusion The system Resilon/Real Seal did not achieve better results in terms of sealing ability in the apical third when compared to the conventional gutta-percha/AH plus sealing system. How to cite this article Zogheib C, Naaman A, Medioni E. Evaluation of Apical Filling after Warm Vertical Compaction using Two Different Endodontic Materials: Resilon® and Gutta-Percha. World J Dent 2012;3(2):166-170.


1987 ◽  
Vol 253 (5) ◽  
pp. E503-E507 ◽  
Author(s):  
T. Matsumoto ◽  
K. Ikeda ◽  
K. Morita ◽  
S. Fukumoto ◽  
H. Takahashi ◽  
...  

To clarify whether extracellular Ca2+ modulates renal 25-hydroxyvitamin D3 [25(OH)D3]-1 alpha-hydroxylase, thyroparathyroidectomized rats were infused with 15 mM CaCl2, 20 mM EGTA, and/or 2.5 U/h parathyroid hormone (PTH), and blood Ca2+, serum 1,25-dihydroxyvitamin D [1,25(OH)2D], and renal 1 alpha-hydroxylase activity were determined. Rats with CaCl2, EGTA, or PTH infusion (group 1) exhibited low blood Ca2+, serum 1,25(OH)2D, and 1 alpha-hydroxylase activities. Infusion of CaCl2 alone (group 2) caused a significant increase in blood Ca2+ and a reduction in serum 1,25(OH)2D and 1 alpha-hydroxylase compared with group 1. Administration of PTH alone (group 3) markedly elevated blood Ca2+, serum 1,25(OH)2D, and 1 alpha-hydroxylase activity. When EGTA was infused along with PTH (group 4), blood Ca2+ was significantly reduced compared with group 3, and serum 1,25(OH)2D and renal 1 alpha-hydroxylase were further elevated. In contrast, when CaCl2 was infused with PTH (group 5), blood Ca2+ was higher than that in group 3, and serum 1,25(OH)2D and 1 alpha-hydroxylase activities were significantly reduced compared with group 3. No significant difference in serum inorganic phosphate or urinary cAMP excretion was observed by CaCl2 or EGTA infusion in both PTH-treated and nontreated rats. These results demonstrate that extracellular Ca2+ modulates the responsiveness of renal 1 alpha-hydroxylase to PTH as well as the base-line activity of the enzyme in the absence of PTH. These effects of extracellular Ca2+ on renal 1 alpha-hydroxylase may serve to offer an efficient way of regulating 1,25(OH)2D production and serum 1,25(OH)2D concentration by altering the responsiveness of 1 alpha-hydroxylase to PTH and possibly other stimulations depending on the demand for Ca2+.(ABSTRACT TRUNCATED AT 250 WORDS)


2007 ◽  
Vol 8 (7) ◽  
pp. 62-69 ◽  
Author(s):  
Emre Ozel ◽  
Idil Dikbas ◽  
Jale Tanalp ◽  
Temel Koksal ◽  
Mustafa Ersoy

Abstract Aim The purpose of this study was to evaluate the fracture resistance of endodontically treated maxillary central incisors restored with quartz fiber posts, composite cores, and crowns when different types of ferrule designs were incorporated. Methods and Materials Sixty maxillary incisors were divided into six groups: Group 1 (control): teeth with root canal treatments having a full crown prosthesis; Group 2: teeth with a 2 mm circumferential ferrule; Group 3: teeth with a 2 mm ferrule only in the vestibular region; Group 4: teeth with a 2 mm ferrule only in the palatal region; Group 5: teeth with a 2 mm ferrule in the vestibular and palatal region, having cavities in both proximal areas; and Group 6: teeth with no ferrule. The teeth in the experimental groups were restored with quartz fiber posts-composite cores and full metallic crowns. All experimental teeth were subjected to an increasing compressive force with a crosshead speed of 1 mm/min, until fracture occurred. Results The median fracture values of groups were as follows: Group 1: 574.4 N, Group 2: 472.4 N, Group 3: 474.3 N, Group 4: 480.7 N, Group 5: 463.1 N, and Group 6: 297.9 N. A statistically significant difference was found between Group 1 and Group 6 (p< 0.01). Conclusion It was concluded different ferrule designs did not have any influence on the fracture resistance of teeth with fiber posts. The results of this study indicate fiber posts can safely be used for their reinforcing properties. Furthermore, there is no significant change in the resistance of teeth with fiber posts regardless of which ferrule design is incorporated. The property of these types of posts is an additional advantage in clinical practice. Citation Dikbas I, Tanalp J, Ozel E, Koksal T, Ersoy M. Evaluation of the Effect of Different Ferrule Designs on the Fracture Resistance of Endodontically Treated Maxillary Central Incisors Incorporating Fiber Posts, Composite Cores and Crown Restorations. J Contemp Dent Pract 2007 November; (8)7:062-069.


2002 ◽  
Vol 126 (3) ◽  
pp. 290-295 ◽  
Author(s):  
Binoy Chandy ◽  
Fleurette Abreo ◽  
Raja Nassar ◽  
Fred J. Stucker ◽  
Cherie-Ann Nathan

OBJECTIVE: eIF4E (4E) is elevated in 100% of head and neck squamous cell carcinoma (HNSCC) and in premalignant lesions of the larynx. However, it is not elevated in normal mucosa. In this study, we hypothesize that 4E is not significantly elevated in inflammation unlike its expression in premalignant lesions of the oral cavity. STUDY DESIGN: Biopsies from the oral cavity were divided into 5 groups: (1) normal mucosa, (2) chronic inflammation, (3) mild dysplasia from leukoplakic lesions, (4) mild dysplasia in surgical margins of patients with HNSCC, and (5) HNSCC. Immunohistochemical qualitative analysis was then performed. RESULTS: None of the 15 specimens in group 1 and 100% of the 15 specimens in group 5 expressed 4E. Of the 29 specimens in group 2 only 4/29 (13%) overexpressed 4E compared with 10/31 (32%) in group 3 and 9/21 (42%) in group 4. There was a significant difference between groups 2 and 3 and groups 2 and 4 ( P < 0.0001 and P < 0.003 respectively) but no significant difference between groups 1 and 2 ( P = 0.13) and between groups 3 and 4 ( P = 0.30). CONCLUSION: 4E is not significantly elevated in inflammation of the oral cavity thus fulfilling one of the criteria that biomarkers require to be useful in a clinical setting.


Author(s):  
Michele Méndez Velázquez

Aim: Sodium hypochlorite is the most common solution in the Endodontics field, however, NaOCl concentrations of commercial brands which are prepared for this purpose differ from their actual concentration. The aim of this study was to compare the physicochemical properties of dental and household hypochlorites. Materials and Methods: The solutions were divided in the following groups: Control: Clorarex 6%, Group 1: Viarzoni-T 5.25%, Group 2: Endo Chlord 3%, Group 3: Chlor- XTRA 6%, Group 4: Viarzoni-T (diluted from 5.25%), Group 5: Cloralex (diluted from 6%), Group 6: Chlor- Xtra (diluted from 6%). pH and temperature were measured by means of potentiometer, dilution test was performed using bovine tissue and exposed to each solution. For cytotoxicity assay, erythrocytes were exposed to each solution and stained with Sternheimer-Malbin solution. Results: Dissolution times showed a significant difference since the shortest time was Cloralex (6.6 ± 2.09). The solution with the highest alkalinity in the original concentration was Endo Chlord for dental use (11.7 ± 2.2). The solution with the highest alkalinity in the original concentration was Endo Chlord for dental use (11.7 ± 2.2) but it also was the solution with less cytotoxicity. Conclusion: Viarzoni-T was the only solution without any dissolving capacity, Cloralex, ChorlXtra and EndoChlord were capable of dissolving bovine pulp tissue effectively, reducing their concentration of Cloralex and ChlorXtra did not reduce the pH, but all solutions showed a cytotoxic effect on erythrocites.


2006 ◽  
Vol 7 (4) ◽  
pp. 9-16 ◽  
Author(s):  
Hend Al-Nahedh ◽  
Nasrien Ateyah

Abstract Aim Despite the improvements to compomer materials, the bond strength of these materials remains inferior to .composite/resin bonding. systems and limits their clinical use. The purpose of this study was to evaluate the effect of acidic conditioning with phosphoric acid and Prompt L-Pop (PLP) on the shear bond strength of two compomers Dyract AP (DAP) and Composan Glass (CG) to dentin. Methods and Materials Sixty extracted bovine teeth were used to test the shear bond strength of two compomers to flat dentin labial surfaces. The dentin specimens were randomly assigned to six groups of ten specimens each: Group 1: DAP and Prime & Bond NT (PBNT); Group 2: DAP/PBNT with a 15 second dentin etch prior to bonding; Group 3: DAP placed with PLP adhesive; Group 4: CG and Compobond NE (CBNE); Group 5: CG/CBNE with a 15 second dentin etch; and Group 6: CG placed with PLP adhesive. The specimens were stored at 37°C with 100% humidity for 24 hours then mounted and sheared using an Instron Universal Testing Machine at a cross head speed of 0.5 mm/min. The results were recorded in Mega Pascals (MPa). The sheared specimens were examined under a light microscope, and the type of failure (adhesive, cohesive, or mixed) was recorded. Results The mean dentin shear bond strength value (MPa) for the groups was: Group 1 (11.6±3.9); Group 2 (13.2±3.3); Group 3 (12.4±2.0); Group 4 (13.0±4.3); Group 5 (19.3±3.7); and Group 6 (13.1±3.0). One way analysis of variance (ANOVA) and Tukey HSD post-hoc tests detected a significantly higher bond strength (P ≤ 0.003) for group 5. For groups 1, 3, 4, and 6, the mode of failure was mostly adhesive. When acid etching of dentin was performed (groups 2 and 5), cohesive fracture within dentin was the predominant mode of failure. Acid etching and the use of PLP significantly reduced the number of adhesive fractures and reduced variability in the shear bond strength results. Conclusions Acid etching significantly increased the shear bond strength of CG to dentin but did not affect DAP. The application of PLP resulted in a shear bond strength not statistically different from PBNT or CPNE. CG bond to dentin is improved with acid etching using phosphoric acid. However, PLP provided no significant improvement in the shear bond strength of DAP and CG. Citation Al-Nahedh H, Ateyah N. Effect of Different Bonding Conditions on the Shear Bond Strength of Two Compomers to Bovine Dentin. J Contemp Dent Pract 2006 September;(7)4:009-016.


2017 ◽  
Vol 7 ◽  
pp. 273-278
Author(s):  
Gaurang H. Chaudhary ◽  
Gianina Salton Mattevi ◽  
Peter Thiuri Gakunga

Objectives The aim of this study was to compare the shear bond strength (SBS) of brackets systems with four different base technologies. Materials and Methods Maxillary first premolars were randomly divided into four groups of thirty specimens each: (1) Master Series™ conventional twin, (2) T3™ self-ligating, (3) Victory series™ conventional twin, and (4) H4™ self-ligating brackets. Maxillary first premolars were bracketed using an acid-etch composite system, and the SBS measured using an Instron Universal Testing Machine at a crosshead speed of 2 mm/min. The ANOVA and Tukey’s multiple comparison tests were performed with significance predetermined at P ≤ 0.05. Results The overall mean bond strengths were 8.49 ± 2.93, 10.85 ± 3.34, 9.42 ± 2.97, and 9.73 ± 2.62 for the Groups 1, 2, 3, and 4 brackets, respectively. One-way ANOVA test gave an F = 3.182 with a P = 0.026. The Group 1 and Group 2 were observed to have statistically significant difference with a P = 0.014. Conclusions The T3 self-ligating one-piece design with microetched Quadra Grip™ base brackets had the highest bond strength. The SBS difference between Group 2, Group 3, and Group 4 was not significant, but the difference between Group 2 and Group 1 was statistically significant.


VASA ◽  
2020 ◽  
Vol 49 (4) ◽  
pp. 281-284
Author(s):  
Atıf Yolgosteren ◽  
Gencehan Kumtepe ◽  
Melda Payaslioglu ◽  
Cuneyt Ozakin

Summary. Background: Prosthetic vascular graft infection (PVGI) is a complication with high mortality. Cyanoacrylate (CA) is an adhesive which has been used in a number of surgical procedures. In this in-vivo study, we aimed to evaluate the relationship between PVGI and CA. Materials and methods: Thirty-two rats were equally divided into four groups. Pouch was formed on back of rats until deep fascia. In group 1, vascular graft with polyethyleneterephthalate (PET) was placed into pouch. In group 2, MRSA strain with a density of 1 ml 0.5 MacFarland was injected into pouch. In group 3, 1 cm 2 vascular graft with PET piece was placed into pouch and MRSA strain with a density of 1 ml 0.5 MacFarland was injected. In group 4, 1 cm 2 vascular graft with PET piece impregnated with N-butyl cyanoacrylate-based adhesive was placed and MRSA strain with a density of 1 ml 0.5 MacFarland was injected. All rats were scarified in 96th hour, culture samples were taken where intervention was performed and were evaluated microbiologically. Bacteria reproducing in each group were numerically evaluated based on colony-forming unit (CFU/ml) and compared by taking their average. Results: MRSA reproduction of 0 CFU/ml in group 1, of 1410 CFU/ml in group 2, of 180 200 CFU/ml in group 3 and of 625 300 CFU/ml in group 4 was present. A statistically significant difference was present between group 1 and group 4 (p < 0.01), between group 2 and group 4 (p < 0.01), between group 3 and group 4 (p < 0.05). In terms of reproduction, no statistically significant difference was found in group 1, group 2, group 3 in themselves. Conclusions: We observed that the rate of infection increased in the cyanoacyrylate group where cyanoacrylate was used. We think that surgeon should be more careful in using CA in vascular surgery.


2019 ◽  
Vol 17 (4) ◽  
pp. 354-364
Author(s):  
Hassan Al-Thani ◽  
Moamena El-Matbouly ◽  
Maryam Al-Sulaiti ◽  
Noora Al-Thani ◽  
Mohammad Asim ◽  
...  

Background: We hypothesized that perioperative HbA1c influenced the pattern and outcomes of Lower Extremity Amputation (LEA). Methods: A retrospective analysis was conducted for all patients who underwent LEA between 2000 and 2013. Patients were categorized into 5 groups according to their perioperative HbA1c values [Group 1 (<6.5%), Group 2 (6.5-7.4%), Group 3 (7.5-8.4%), Group 4 (8.5-9.4%) and Group 5 (≥9.5%)]. We identified 848 patients with LEA; perioperative HbA1c levels were available in 547 cases (Group 1: 18.8%, Group 2: 17.7%, Group 3: 15.0%, Group 4: 13.5% and Group 5: 34.9%). Major amputation was performed in 35%, 32%, 22%, 10.8% and 13.6%, respectively. Results: The overall mortality was 36.5%; of that one quarter occurred during the index hospitalization. Mortality was higher in Group 1 (57.4%) compared with Groups 2-5 (46.9%, 38.3%, 36.1% and 31.2%, respectively, p=0.001). Cox regression analysis showed that poor glycemic control (Group 4 and 5) had lower risk of mortality post-LEA [hazard ratio 0.57 (95% CI 0.35-0.93) and hazard ratio 0.46 (95% CI 0.31-0.69)]; this mortality risk persisted even after adjustment for age and sex but was statistically insignificant. The rate of LEA was greater among poor glycemic control patients; however, the mortality was higher among patients with tight control. Conclusion: The effects of HbA1c on the immediate and long-term LEA outcomes and its therapeutic implications need further investigation.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yu Liu ◽  
Jing Li ◽  
Wanyu Zhang ◽  
Yihong Guo

AbstractOestradiol, an important hormone in follicular development and endometrial receptivity, is closely related to clinical outcomes of fresh in vitro fertilization-embryo transfer (IVF-ET) cycles. A supraphysiologic E2 level is inevitable during controlled ovarian hyper-stimulation (COH), and its effect on the outcome of IVF-ET is controversial. The aim of this retrospective study is to evaluate the association between elevated serum oestradiol (E2) levels on the day of human chorionic gonadotrophin (hCG) administration and neonatal birthweight after IVF-ET cycles. The data of 3659 infertile patients with fresh IVF-ET cycles were analysed retrospectively between August 2009 and February 2017 in First Hospital of Zhengzhou University. Patients were categorized by serum E2 levels on the day of hCG administration into six groups: group 1 (serum E2 levels ≤ 1000 pg/mL, n = 230), group 2 (serum E2 levels between 1001 and 2000 pg/mL, n = 524), group 3 (serum E2 levels between 2001 and 3000 pg/mL, n = 783), group 4 (serum E2 levels between 3001 and 4000 pg/mL, n = 721), group 5 (serum E2 levels between 4001 and 5000 pg/mL, n = 548 ), and group 6 (serum E2 levels > 5000 pg/mL, n = 852). Univariate linear regression was used to evaluate the independent correlation between each factor and outcome index. Multiple logistic regression was used to adjust for confounding factors. The LBW rates were as follows: 3.0% (group 1), 2.9% (group 2), 1.9% (group 3), 2.9% (group 4), 2.9% (group 5), and 2.0% (group 6) (P = 0.629), respectively. There were no statistically significant differences in the incidences of neonatal LBW among the six groups. We did not detect an association between peak serum E2 level during ovarian stimulation and neonatal birthweight after IVF-ET. The results of this retrospective cohort study showed that serum E2 peak levels during ovarian stimulation were not associated with birth weight during IVF cycles. In addition, no association was found between higher E2 levels and increased LBW risk. Our observations suggest that the hyper-oestrogenic milieu during COS does not seem to have adverse effects on the birthweight of offspring after IVF. Although this study provides some reference, the obstetric-related factors were not included due to historical reasons. The impact of the high estrogen environment during COS on the birth weight of IVF offspring still needs future research.


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