scholarly journals Debonding Time and Dental Pulp Temperature With the Er, Cr: YSGG Laser for Debonding Feldespathic and Lithium Disilicate Veneers

2019 ◽  
Vol 10 (3) ◽  
pp. 211-214 ◽  
Author(s):  
Marzieh Alikhasi ◽  
Abbas Monzavi ◽  
Hooman Ebrahimi ◽  
Maryam Pirmoradian ◽  
Ahmadreza Shamshiri ◽  
...  
Keyword(s):  
Glass Ceramic ◽  
Temperature Increase ◽  
Lithium Disilicate ◽  
Ceramic Materials ◽  
Resin Cement ◽  
P Value ◽  
Significance Level ◽  
Ysgg Laser ◽  
Significant Difference ◽  
Pulp Temperature

Introduction: The removal of ceramic veneers is a time-consuming procedure in a dental office. Little research has been done in alternative removal techniques for ceramic veneers. The objective of this study was to evaluate the removal of feldspathic and lithium disilicate reinforced glass ceramic veneers by Er, Cr: YSGG and to measure debonding time and pulpal temperature increase during veneer removal. Methods: Fifty-seven bovine incisor teeth were prepared and divided into 3 groups. Ceramic specimens with a thickness of 0.7mm, a width of 4mm and a length of 8 mm were fabricated from feldspathic ceramic, lithium disilicate reinforced glass ceramic HT (high translucency) and lithium disilicate reinforced glass ceramic MO (medium opacity) (19 for each group). Specimens were cemented on the labial surface of incisors using resin cement. The Er, Cr: YSGG laser was applied to each specimen at 2.5 W and 25 Hz. Debonding time was measured for each specimen, and the intrapulpal temperature was detected in 3 specimens for each group. Data were analyzed via one-way analysis of variance (ANOVA) at significance level of 0.05 (α = 0.05). Results: Mean debonding time was 103.68 (26.76), 106.58 (47.22) and 103.84 (32.90) seconds for feldspathic, lithium disilicate MO, and lithium disilicate HT respectively. There was no significant statistical difference among the groups (P value = 0.96). The intrapulpal temperature increase was less than 1°C in all groups. Conclusion: Er, Cr: YSGG can successfully be used to efficiently debond feldspathic and lithium disilicate reinforced glass ceramic veneers. There was no significant difference for debonding time among these ceramic materials. During ceramic laminate veneer removal by laser irradiation, no irritating temperature rise was detected.

Influence of Ceramic Thickness and Ceramic Materials on Fracture Resistance of Posterior Partial Coverage Restorations

2015 ◽  
Vol 40 (2) ◽  
pp. 211-217 ◽  
Author(s):  
EM Bakeman ◽  
N Rego ◽  
Y Chaiyabutr ◽  
JC Kois
Keyword(s):  
Glass Ceramic ◽  
Fracture Resistance ◽  
Testing Machine ◽  
Lithium Disilicate ◽  
Ceramic Materials ◽  
Tooth Structure ◽  
Partial Coverage ◽  
Significant Difference ◽  
Ceramic Thickness ◽  
Ceramic Restorations

SUMMARY This study evaluated the influence of ceramic thickness and ceramic materials on fracture resistance of posterior partial coverage ceramic restorations. Forty extracted molars were allocated into four groups (n=10) to test for two variables: 1) the thickness of ceramic (1 mm or 2 mm) and 2) the ceramic materials (a lithium disilicate glass-ceramic [IPS e.max] or leucite-reinforced glass ceramic [IPS Empress]). All ceramic restorations were luted with resin cement (Variolink II) on the prepared teeth. These luted specimens were loaded to failure in a universal testing machine, in the compression mode, with a crosshead speed of 1.0 mm/min. The data were analyzed using two-way analysis of variance and the Tukey Honestly Significantly Different multiple comparison test (α =0.05). The fracture resistance revealed a significant effect for materials (p<0.001); however, the thickness of ceramic was not significant (p=0.074), and the interaction between the thickness of ceramic and the materials was not significant (p=0.406). Mean (standard deviation) fracture resistance values were as follows: a 2-mm thickness of a lithium disilicate bonded to tooth structure (2505 [401] N) revealed a significantly higher fracture resistance than did a 1-mm thickness of leucite-reinforced (1569 [452] N) and a 2-mm thickness of leucite-reinforced ceramic bonded to tooth structure (1716 [436] N) (p<0.05). There was no significant difference in fracture resistance values between a lithium disilicate ceramic at 1-mm thickness (2105 [567] N) and at 2-mm thickness. Using a lithium disilicate glass ceramic for partial coverage restoration significantly improved fracture resistance compared to using a leucite-reinforced glass ceramic. The thickness of ceramic had no significant effect on fracture resistance when the ceramics were bonded to the underlying tooth structure.

Effect of Storage Time on Bond Strength Performance of Multimode Adhesives to Indirect Resin Composite and Lithium Disilicate Glass Ceramic

2016 ◽  
Vol 41 (5) ◽  
pp. 541-551 ◽  
Author(s):  
P Makishi ◽  
CB André ◽  
JP Lyra e Silva ◽  
R Bacelar-Sá ◽  
L Correr-Sobrinho ◽  
...  
Keyword(s):  
Bond Strength ◽  
Glass Ceramic ◽  
Resin Composite ◽  
Water Storage ◽  
Lithium Disilicate ◽  
Resin Cement ◽  
Control Group ◽  
Strength Performance ◽  
Significant Difference ◽  
One Year

SUMMARY Purpose: To investigate the bond strength performance of multimode adhesives (MMAs) to indirect resin composite and lithium disilicate glass ceramic after 24 hours or one year of water storage. Methods and Materials: Thirty flat and polished plates of indirect resin composite (Epricord) and thirty lithium disilicate glass ceramic plates (IPS e.max Press) were prepared. Surfaces were pretreated using sandblasting (indirect resin composite) or hydrofluoric acid (glass-based ceramic). Specimens were bonded with one of two MMAs (Scotchbond Universal [SBU] or All-Bond Universal [ABU]) or ceramic primer and hydrophobic bonding (RelyX Ceramic Primer and Adper Scotchbond Multi-Purpose Bond) as a control (n=10). Resin cement cylinders (0.75 mm in diameter × 0.5 mm in height) were bonded to both substrate surfaces using the respective adhesives. After 24 hours or one year of water storage, bonding performance was measured by microshear bond strength (MSBS) testing. Results were analyzed using three-way ANOVA with Bonferroni post hoc tests (α=0.05). Results: For indirect resin composite, significantly higher MSBS values were found for ABU after 24 hours (ABU > SBU = control); however, no significant difference among the adhesives was observed after one year (p>0.05). For glass-based ceramic, significantly different bond strengths were observed among the adhesives after 24 hours (control = ABU > SBU) and one year (control > SBU = ABU; p<0.05). Conclusions: Both MMAs tested can be considered effective alternatives for bonding to sandblasted indirect resin composite after aging, as they showed similar bond performance to that of the control group. However, separate bottles of silane bonding resin showed higher MSBS values and more durable bonding for etched glass–based ceramic.

scholarly journals Influence of the conditioning technique of a lithium disilicate vitroceramic

RSBO ◽  
2018 ◽  
Vol 15 (1) ◽  
pp. 20-06
Author(s):  
Gisele Maria Correr Nolasco ◽  
Genine Moreira de Freitas Guimarães ◽  
Ricardo Bressan ◽  
Rafaella Ronchi ◽  
Carla Castiglia Gonzaga1 ◽  
...  
Keyword(s):  
Bond Strength ◽  
Shear Test ◽  
Clinical Success ◽  
Testing Machine ◽  
Lithium Disilicate ◽  
Resin Cement ◽  
Ceramic Surface ◽  
Significance Level ◽  
Conditioning Process ◽  
Significant Difference

Lithium disilicate reinforced glass ceramics are materials that require good adhesion to ensure clinical success. Objective: To evaluate the bond strength of resin cements to lithium-disilicateenhanced vitroceramics using different cleaning techniques of recently conditioned ceramics. Material and methods: Twelve ceramic discs (IPS Empress II) were made and inserted into PVC pipes using acrylic resin. The ceramic surface was designed and submitted to a 10% hydrofluoric acid conditioning process for 20s. Then, the specimens were divided into 3 groups (n = 16) according to the cleaning techniques of recently conditioned ceramics: 1) control - conventional technique (no cleaning after the conditioning process); 2) application of 37% phosphoric acid for 20s; 3) 90% ethyl alcohol bath in a ultrasound tub for 4 min. After cleaning, the silane agent was applied for 1 minute and silicon matrices (1 mm in diameter x 1 mm in height) were made for further application of the resin cement (Vitique, DMG), which was handled according to the manufacturer’s instructions. Four cylinders were prepared on each ceramic surface. The specimens were stored in distilled water for 48 hours and subjected to the micro-shear test in a universal testing machine. After the micro-shear test, a failure analysis of the specimens was performed. Data were submitted to ANOVA (analysis of variance for a criterion) with a significance level of 5%. Results: There was no significant difference between groups (p > 0.05). Conclusion: the cleaning technique of the recently conditioned ceramics does not interfere with the resin/cement bond strength values.

scholarly journals Influence of the conditioning technique of a lithium disilicate vitroceramic

RSBO ◽  
2018 ◽  
Vol 1 (1) ◽  
pp. 20
Author(s):  
Gisele Maria Correr Nolasco ◽  
Genine Moreira de Freitas Guimarães ◽  
Ricardo Bressan ◽  
Rafaella Ronchi ◽  
Carla Castiglia Gonzaga ◽  
...  
Keyword(s):  
Bond Strength ◽  
Shear Test ◽  
Clinical Success ◽  
Testing Machine ◽  
Lithium Disilicate ◽  
Resin Cement ◽  
Ceramic Surface ◽  
Significance Level ◽  
Conditioning Process ◽  
Significant Difference

Introduction: Lithium disilicate reinforced glass ceramics are materials that require good adhesion to ensure clinical success. Objective: To evaluate the bond strength of resin cements to lithium-disilicateenhanced vitroceramics using different cleaning techniques of recently conditioned ceramics. Material and methods: Twelve ceramic discs (IPS Empress II) were made and inserted into PVC pipes using acrylic resin. The ceramic surface was designed and submitted to a 10% hydrofluoric acid conditioning process for 20s. Then, the specimenswere divided into 3 groups (n = 16) according to the cleaning techniques of recently conditioned ceramics: 1) control - conventional technique (no cleaning after the conditioning process); 2) application of 37% phosphoric acid for 20s; 3) 90% ethyl alcohol bath in a ultrasound tub for 4 min. After cleaning, the silane agent was applied for 1 minute and silicon matrices (1 mm in diameter x 1 mm in height) were made for further application of the resin cement (Vitique, DMG), which was handled according to the manufacturer’s instructions. Four cylinders were prepared on each ceramic surface. The specimens were storedin distilled water for 48 hours and subjected to the micro-shear test in a universal testing machine. After the micro-shear test, a failure analysis of the specimens was performed. Data were submitted to ANOVA (analysis of variance for a criterion) with a significance level of 5%. Results: There was no significant difference between groups (p > 0.05). Conclusion: the cleaning technique of the recently conditioned ceramics does not interfere with the resin/cement bond strength values

scholarly journals An Analysis of the Relationship Between Job Satisfaction and Employee Engagement

2017 ◽  
Vol 55 (2) ◽  
pp. 243-262 ◽  
Author(s):  
Anton Vorina ◽  
Miro Simonič ◽  
Maria Vlasova
Keyword(s):  
Job Satisfaction ◽  
Employee Engagement ◽  
Business Performance ◽  
Modern World ◽  
P Value ◽  
Significance Level ◽  
The Public ◽  
Significant Difference ◽  
And Gender ◽  
The Relationship

AbstractThis paper examines the relationship between employee engagement and job satisfaction. People spend most of their time at work, and their motivation is considered to be an important factor for job performance. Enthusiastic employees, who focus their efforts on achieving their companies′ goals are a key competitive advantage in the modern world. The effect of employee engagement on business performance has been studied by various experts. They found out the similar conclusion: “the more enthusiastic the workers are, the better operating results they achieve for the company”. An occasional sample of 594 respondents who are employed in the public and non-public sector in Slovenia was used for the purpose of this study. The main goal of the research is to determine whether (and how) the employee engagement influences job satisfaction. A written survey was conducted from 4 January 2016 to 14 March 2016. IBM SPSS 20 was used for the statistical analysis. The results confirm that the relationship between employee engagement and job satisfaction is positive and statistically significant (5 % significance level), based on the linear regression F (1, 583) =296.14, p-value = 0.000, R-square = 0.337. The results also show that there is no statistically significant difference between employee engagement and gender and there is no statistically significant difference between job satisfaction and gender.

scholarly journals Studi Komparasi Penerapan Model Guided Discovery Learning dan Inquiry Learning terhadap Retensi Matematika

2019 ◽  
Vol 19 (3) ◽  
pp. 524
Author(s):  
Lilik Masfiyah ◽  
Rufi'i Rufi'i ◽  
Harwanto Harwanto
Keyword(s):  
Inquiry Learning ◽  
Learning Model ◽  
Discovery Learning ◽  
P Value ◽  
Retention Data ◽  
Guided Discovery ◽  
Significance Level ◽  
Significant Difference ◽  
Written Test ◽  
Academic Year

This study aimed to examine the differences in mathematics retention of grade V Primary school between students who were taught using guided discovery learning model and inquiry learning model. The method in this study was a quasy experimnetal method. The population in this study was all students in grade V at SDN Pongangan and SDN Sukomulyo in 2018/2019 academic year which in total were 202 students. Samples were selected by purposive random sampling. The sample was divided into two group which are experiment 1 and experiment 2. The instrument used to collect mathematics retention data was a written test. The Data was analysed using descriptive statistic analysis and t-test. The results of data analysis at 0,05 significance level and df = 130 showed that t-count (2,276) > t-tabel (1,978) and also p-value (2-tailed) 0,024 < 0,05. So, it mean that there was a significant difference in mathematics retention between students who were taught using guided discovery learning model and inquiry learning model.

scholarly journals Effect of Nd:YAG Laser with/without Graphite Coating on Bonding of Lithium Disilicate Glass-Ceramic to Human Dentin

2021 ◽  
Vol 2021 ◽  
pp. 1-7
Author(s):  
Amjad Abu Hasna ◽  
Stephanie Semmelmann ◽  
Fernanda Alves Feitosa ◽  
Danilo De Souza Andrade ◽  
Franklin R Tay ◽  
...  
Keyword(s):  
Bond Strength ◽  
Glass Ceramic ◽  
Nd:Yag Laser ◽  
Testing Machine ◽  
Glass Ceramics ◽  
Lithium Disilicate ◽  
Resin Cement ◽  
Cylindrical Shape ◽  
Universal Testing ◽  
Human Dentin

This study evaluated the effect of different surface treatments on the tensile bond strength between lithium disilicate glass-ceramics, resin cement, and dentin. Fifty truncated cone-shape glass-ceramics were divided into five groups (n = 10): G1, control: 10% hydrofluoric acid (HF); G2, Nd:YAG laser + silane; G3, Sil + Nd:YAG laser; G4, graphite + Nd:YAG laser + Sil; and G5, graphite + Sil + Nd:YAG laser. Fifty human third-molars were cut to cylindrical shape and polished to standardize the bonding surfaces. The glass-ceramic specimens were bonded to dentin with a dual-cured resin cement and stored in distilled water for 24 h at 37ºC. Tensile testing was performed on a universal testing machine (10 Kgf load cell at 1 mm/min) until failure. The bond strength values (mean ± SD) in MPa were G1 (9.4 ± 2.3), G2 (9.7 ± 2.0), G3 (6.7 ± 1.9), G4 (4.6 ± 1.1), and G5 (1.2 ± 0.3). Nd:YAG laser and HF improve the bond strength between lithium disilicate glass-ceramics, resin cement, and dentin. The application of a graphite layer prior to Nd:YAG laser irradiation negatively affects this bonding and presented inferior results.

scholarly journals LED and Halogen Light Transmission through a CAD/CAM Lithium Disilicate Glass-Ceramic

2015 ◽  
Vol 26 (6) ◽  
pp. 648-653 ◽  
Author(s):  
Carolina Nemesio de Barros Pereira ◽  
Cláudia Silami de Magalhães ◽  
Bruno Daleprane ◽  
Rogéli Tibúrcio Ribeiro da Cunha Peixoto ◽  
Raquel da Conceição Ferreira ◽  
...  
Keyword(s):  
Regression Model ◽  
Glass Ceramic ◽  
Light Transmission ◽  
Light Attenuation ◽  
Lithium Disilicate ◽  
Strong Negative Correlation ◽  
Halogen Light ◽  
Significant Difference ◽  
Cad Cam ◽  
Ceramic Thickness

The effect of thickness, shade and translucency of CAD/CAM lithium disilicate glass-ceramic on light transmission of light-emitting diode (LED) and quartz-tungsten-halogen units (QTH) were evaluated. Ceramic IPS e.max CAD shades A1, A2, A3, A3.5, high (HT) and low (LT) translucency were cut (1, 2, 3, 4 and 5 mm). Light sources emission spectra were determined. Light intensity incident and transmitted through each ceramic sample was measured to determine light transmission percentage (TP). Statistical analysis used a linear regression model. There was significant interaction between light source and ceramic translucency (p=0.008) and strong negative correlation (R=-0.845, p<0.001) between ceramic thickness and TP. Increasing one unit in thickness led to 3.17 reduction in TP. There was no significant difference in TP (p=0.124) between shades A1 (ß1=0) and A2 (ß1=-0.45) but significant reduction occurred for A3 (ß1=-0.83) and A3.5 (ß1=-2.18). The interaction QTH/HT provided higher TP (ß1=0) than LED/HT (ß1=-2.92), QTH/LT (ß1=-3.75) and LED/LT (ß1=-5.58). Light transmission was more effective using halogen source and high-translucency ceramics, decreased as the ceramic thickness increased and was higher for the lighter shades, A1 and A2. From the regression model (R2=0.85), an equation was obtained to estimate TP value using each variable ß1 found. A maximum TP of 25% for QTH and 20% for LED was found, suggesting that ceramic light attenuation could compromise light cured and dual cure resin cements polymerization.

scholarly journals The Effect of Hydrofluoric Acid Concentration and Heat on the Bonding to Lithium Disilicate Glass Ceramic

2016 ◽  
Vol 27 (6) ◽  
pp. 727-733 ◽  
Author(s):  
Daniel Sundfeld ◽  
Lourenço Correr-Sobrinho ◽  
Núbia Inocêncya Pavesi Pini ◽  
Ana Rosa Costa ◽  
Renato Herman Sundfeld ◽  
...  
Keyword(s):  
Bond Strength ◽  
Glass Ceramic ◽  
Hydrofluoric Acid ◽  
Lithium Disilicate ◽  
Resin Cement ◽  
Glassy Matrix ◽  
Etching Time ◽  
Sem Images ◽  
Matrix Removal ◽  
Post Hoc

Abstract The aim of this study was to evaluate the effects of hydrofluoric acid (HF) concentration and previous heat treatment (PHT) on the surface morphology and micro-shear bond strength (mSBS) of a lithium disilicate glass ceramic (EMX) to resin cement. One hundred four EMX specimens were randomly assigned to two groups (n=52) according to the HF concentration: 5% and 10%. A new random distribution was made according to the PHTs (n=13): control (no PHT); previously heated HF (70 °C); previously heated EMX surface (85 °C); the combination of heated HF + heated EMX surface. The etching time was set at 20 s. All EMX blocks were silanated and received a thin layer of an unfilled resin. Five resin cement cylinders were made on each EMX surface using Tygon tubes as matrices, and then stored for 24 h at 37 °C. One random etched EMX sample from each group was analyzed using field-emission scanning electron microscopy (FE-SEM). The data were subjected to two-way ANOVA and multiple comparisons were performed using the Tukey post hoc test (a=0.05). For the control groups, 5% HF showed statistically lower mSBS values when compared to 10% HF (p<0.05). PHT increased the mSBS values for 5% HF, yielding statistically similar results to non-PHT 10% HF (p<0.05). FE-SEM images showed increased glassy matrix removal when PHT was applied to HF 5%, but not to the same degree as for 10% HF. PHT has the potential to improve the bond strength of 5% HF concentration on lithium disilicate glass ceramic.

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