scholarly journals Influence of the Number of Bleaching Sessions on Fracture Resistance and Dentin Microhardness of Endodontically Treated Teeth

2017 ◽  
Vol 8 (1) ◽  
pp. 5-9
Author(s):  
Matheus Coelho Bandeca ◽  
Milton C Kuga ◽  
Keren CF Jordão-Basso ◽  
Mateus R Tonetto ◽  
Suellen L Lima ◽  
...  

ABSTRACT Objectives To evaluate the effects of number of bleaching sessions on fracture resistance and dentin microhardness in endodontically treated teeth using 15% hydrogen peroxide with titanium dioxide nanoparticles (15HPTiO2) associated to light emitting diode (LED)—laser system. Materials and methods Forty human incisors were endodontically treated and divided according to the number of bleaching sessions (n = 10, each group): G1 — no treatment G2 — one; G3 — two; and G4 — three sessions. The 15HPTiO2 was applied within the pulp chamber and on the buccal surface, then photoactivated using LED—laser. All experimental specimens were restored with ionomer glass cement between each session and in the final treatment. Specimens were then subjected to the fracture resistance test (kN), using an electromechanical machine. To the dentin microhardness evaluation, 40 crown extracted endodontically treated human teeth were longitudinally sectioned, divided into groups as previously described (n = 10), and submitted to similar bleaching protocol. Dentin microhardness was evaluated before and after the final dental bleaching session in each group using Knoop indentator. Data were analyzed by analysis of variance (ANOVA) and Tukey tests (p = 0.05). Results The fracture resistance values were similar among all groups (p > 0.05). The number of dental bleaching sessions had a negative influence on the microhardness dentin, because G4 > G3 > G2 > G1 (p < 0.05). Conclusion The number of bleaching sessions using 15% hydrogen peroxide with titanium dioxide nanoparticles associated to LED—laser system had no influence on the fracture resistance of the endodontically treated teeth crowns, but promoted a reduction in dentin microhardness. How to cite this article Garrido LDMA, Kuga MC, Kalatzis- Sousa NG, Dantas AAR, Tonetto MR, Leonardo RDT, Jordão- Basso KCF, Lima SL, Borges AH, Bandeca MC. Influence of the Number of Bleaching Sessions on Fracture Resistance and Dentin Microhardness of Endodontically Treated Teeth. World J Dent 2017;8(1):5-9.

2014 ◽  
Vol 43 (3) ◽  
pp. 153-157
Author(s):  
Keren Cristina JORDÃO-BASSO ◽  
Carolina ANDOLFATTO ◽  
Milton Carlos KUGA ◽  
Gisselle Moraima CHÁVEZ-ANDRADE ◽  
Norberto Batista de FARIA-JÚNIOR ◽  
...  

Objective: The aim of this study was evaluate the fracture resistance of endodontically-treated teeth after bleaching treatment using 15% hydrogen peroxide plus titanium dioxide nanoparticles (15HPTiO2) photoactivated by LED-laser, in comparison with protocols using 35% hydrogen peroxide (35HP), 37% carbamide peroxide (37CP) or sodium perborate (SP). Material and method: After endodontic treatment, fifty bovine extracted incisors were divided into five groups (n = 10): G1- without bleaching; G2- 35HP; G3- 37CP; G4- 15HPTiO2 photoactivated by LED-laser and G5- SP. In G2 and G4, the bleaching protocol was applied in 4 sessions, with a 7 day interval between each session. In G3 and G5, the materials were kept in the pulp chamber for 21 days, but replaced every 7 days. After 21 days, the crowns were subjected to compressive load at a cross head speed of 0.5 mm/min, applied at 135° to the long axis of the root using an eletromechanical testing machine, until fracture. The data were submitted to ANOVA and Tukey tests (p = 0.05). Result: The bleaching treatment in endodontically-treated teeth with 15HP plus TiO2 nanoparticles and photoactivated by LED-laser caused reduction of the fracture resistance similarly provided by 35HP, 37CP or SP (p>0.05). All bleaching treatments reduced the fracture resistance compared to unbleached teeth (p<0.05). Conclusion: All bleaching protocols reduced the fracture resistance of endodontically-treated teeth, but there were no differences between each other.


2014 ◽  
Vol 15 (2) ◽  
pp. 186-189 ◽  
Author(s):  
Renato de Toledo Leonardo ◽  
Edson Alves de Campos ◽  
Katia Cristina Keine ◽  
Milton Carlos Kuga ◽  
Flávia Angélica Guiotti ◽  
...  

ABSTRACT Aim The aim of this study was to evaluate the fracture resistance of teeth submitted to several internal bleaching protocols using 35% hydrogen peroxide (35HP), 37% carbamide peroxide (37CP), 15% hydrogen peroxide with titanium dioxide nanoparticles (15HPTiO2) photoactivated by LED-laser or sodium perborate (SP). Materials and methods After endodontic treatment, fifty bovine extracted teeth were divided into five groups (n = 10): G1—unbleached; G2—35HP; G3—37CP; G4—15HPTiO2 photoactivated by LED-laser and G5—SP. In the G2 and G4, the bleaching protocol was applied in 4 sessions, with 7 days intervals between each session. In the G3 and G5, the materials were kept in the pulp teeth for 21 days, but replaced every 7 days. After 21 days, the teeth were subjected to compressive load at a cross head speed of 0.5 mm/min, applied at 135° to the long axis of the root using an eletromechanical testing machine, until teeth fracture. The data were submitted to ANOVA and Tukey tests (á = 5%). Results The 35HP, 37CP, 15HPTiO2 and SP showed similar fracture resistance teeth reduction (p > 0.05). All bleaching treatments reduced the fracture resistance compared to unbleached teeth (p < 0.05). Conclusion All bleaching protocols reduced the fracture resistance of endodontically-treated teeth, but there were no differences between each other. Clinical significance There are several internal bleaching protocols using hydrogen peroxide in different concentrations and activation methods. This study evaluated its effects on fracture resistance in endodontically-treated teeth. How to cite this article de Toledo Leonardo R, Kuga MC, Guiotti FA, Andolfatto C, de Faria-Júnior NB, de Campos EA, Keine KC, Dantas AAR. Fracture Resistance of Teeth Submitted to Several Internal Bleaching Protocols. J Contemp Dent Pract 2014;15(2):186-189.


2014 ◽  
Vol 2 (1) ◽  
pp. 13
Author(s):  
Francisco Carlos Bontorim ◽  
Milton Carlos Kuga ◽  
Sabrina Spinelli Cioffi ◽  
Marcus Vinicius Reis Só ◽  
Gisele Faria ◽  
...  

PURPOSE: This study evaluated the effect of 10% sodium ascorbate (10SA), in gel (10SAg) or aqueous solution (10SAs) formulations, on fracture resistance of endodontically treated tooth submitted to dental bleaching procedures with 15% hydrogen peroxide associated with titanium dioxide (15HP-TiO2) nanoparticles and photoactivated by LED-laser. MATERIAL AND METHODS: Forty maxillary premolars were endodontically-treated and embedded in acrylic resin up to the cement-enamel junction. The specimens were divided into four groups (n=10): G1 (negative control): no bleaching, coronal access restored with composite resin; G2 (positive control): three dental bleaching  sessions using 15HP-TiO2 and LED-laser photoactivation and restored with composite resin (positive control); G3 (10SAg): similar procedures to G2, but applied  10SA, in gel formulation, for 24 hours before restoration; G4 (10SAs): similar procedures to G3, but applied  10SA, in aqueous solution formulation.  The 15HP-TiO2 was applied on buccal and lingual surfaces of the crown tooth and inside the pulp chamber and photoactivated by LED-laser. Between each bleaching session, the teeth were maintained in artificial saliva, at 37oC, for 7 days. In sequence, the teeth were submitted to fracture resistance testing using an eletromechanical machine test. The data was analyzed using Kruskal Wallis test (p = 0.05) RESULTS: There are no differences significant among the groups in relation to fracture resistance of endodontically treated teeth (p>0.05). CONCLUSIONS: The use of 10% sodium ascorbate, in gel or aqueous solution formulations, did not interfered on the fracture resistance teeth after dental bleaching using 15HP-TiO2 and LED-laser photoactivation.


2017 ◽  
Vol 18 (11) ◽  
pp. 1051-1055 ◽  
Author(s):  
Matheus Coelho Bandeca ◽  
Milton C Kuga ◽  
Keren CF Jordão-Basso ◽  
Mateus R Tonetto ◽  
Marina OG Galloza ◽  
...  

ABSTRACT Introduction The aim of this study was to evaluate the effects of bleaching gel using 35% hydrogen peroxide (HP), associated with red carmine pigment (RC), in the 3:1 or 1:1 ratio, on fracture resistance and dentin microhardness of endodontically treated teeth. Materials and methods A total of 40 lower incisors were endodontically treated and divided into four groups (n = 10), according to the bleaching protocol: G1 (HP3), 35% HP + RC (3:1); G2 (HP1), 35% HP + RC (1:1); G3 (positive), 38% HP; and G4 (negative), unbleached. Four dental bleaching sessions were performed. The dental crowns were restored after the last session and submitted to the fracture resistance test. Totally, 60 specimens from the endodontically treated lower incisor crowns were prepared to evaluate the effects on dentin microhardness. The analysis was measured (in Knoop) prior to and after the last dental bleaching session using similar bleaching protocols. Results G2 presented the lowest fracture resistance (p < 0.05). The other groups were similar to each other (p > 0.05). No difference was observed in the reduction of dentin microhardness among the groups (p > 0.05). Conclusion A 1:1 ratio (bleaching gel:pigment) caused a significant fracture resistance reduction in relation to the other protocols. No effect on the dentin microhardness reduction was observed. Clinical significance The pigment addition to the bleaching agent accelerates the bleaching chemical reaction. However, no studies have evaluated the ideal proportion to optimize tooth bleaching. How to cite this article Galloza MOG, Jordão-Basso KCF, Bandeca MC, Costa SO, Borges AH, Tonetto MR, Tirintan FC, Keine KC, Kuga MC. Effects of the Ratio between Pigment and Bleaching Gel on the Fracture Resistance and Dentin Microhardness of endodontically treated Teeth. J Contemp Dent Pract 2017;18(11):1051-1055.


2020 ◽  
Vol 82 (10) ◽  
pp. 2019-2028 ◽  
Author(s):  
Tobias Schnabel ◽  
Simon Mehling ◽  
Jörg Londong ◽  
Christian Springer

Abstract Supported titanium dioxide catalysts were used in a photocatalytic flat cell reactor to remove organic micropollutants from real wastewater. Catalysts based on stainless steel mesh with a porous coating made of titanium dioxide nanoparticles with predominantly anatase modification were used. The influence of the retention time, and light output, and the effect of hydrogen peroxide on the degradation were examined. The kinetics of the degradation of the parent substances was determined by liquid chromatography-tandem mass spectrometry. As a result, first-order degradation kinetics could be confirmed for all substances. The irradiance had no linear influence on the degradation of the compounds. Hydrogen peroxides were added to the wastewater to be treated, as electron acceptors and boosters, and alone had no great oxidative effect on the parent substances. The combination of photocatalysis with the addition of hydrogen peroxide as an electron acceptor had great synergetic effects which can reduce the required energy of the process through a short retention time. The process is suitable for the removal of micropollutants from wastewater.


2009 ◽  
Vol 27 (6) ◽  
pp. 913-919 ◽  
Author(s):  
Ilene Cristine Rosia Cesar ◽  
Luís Eduardo Silva Soares ◽  
Leandro Procópio Alves ◽  
Airton Abrahão Martin ◽  
Egberto Munin ◽  
...  

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