Effect of calcium hydroxide on pH changes of the external medium after intracoronal bleaching

Aim: This in vitro study evaluated the effect of calcium hydroxide on pH changes of the external medium after intracoronal bleaching. Materials and methods: A total of 50 extracted human premolars were prepared and filled with gutta-percha and endodontic sealer. The teeth were randomly divided into five groups according to the bleaching agents employed: (a) Sterile cotton pellet with distilled water (control group); (b) sodium perborate and distilled water; (c) sodium perborate and 10% carbamide peroxide; (d) sodium perborate and 35% hydrogen peroxide; (e) 35% hydrogen peroxide. The teeth were stored in vials containing distilled water and the pH values of the medium surrounding the teeth were analyzed. After 7-day storage, the bleaching agent was removed and replaced by calcium hydroxide, and the distilled water was changed, in which the teeth were kept stored for further 14 days. Measurement of pH of the external medium (distilled water) was performed 7 days after insertion of the bleaching agents, immediately, 7 and 14 days after insertion of the calcium hydroxide. Data were submitted to statistical analysis by the two-way ANOVA and Tukey,s test. Results: There were pH changes of the external medium at 7-day period after bleaching procedures. These results confirmed the diffusion of bleaching agents to the external medium. Conclusion: Calcium hydroxide increased the external medium pH and was effective for pH alkalinization after intracoronal bleaching. Clinical significance: Intracoronal bleaching of endodontically treated teeth may cause cervical root resorption. A possible explanation for this process is the passage of bleaching agents to the periodontal tissues yielding an inflammatory process. In an attempt to keep the neutrality of the periodontal pH, the calcium hydroxide has been recommended.Results of this study showed that this material should be always used after intracoronal bleaching.

A comparative study of the physical properties of conventional and Grander-modified adhesive systems

Purpose: The objective of this study was to evaluate the influence of the Grander technology in reducing the surface tension and contact angle of a self-etch adhesive system. Methods: Distilled water and Xeno III self-etch adhesive system (Dentsply) were modified by physical contact with the Flexible unit Grander system to revitalize water, for 48 hours, resulting in four groups: Group 1 - Xeno III under normal conditions; Group 2 - Xeno III modified by Grander; Group 3 - distilled water under normal conditions; Group 4 - distilled water system modified by the Grander system;. Surface tension and contact angle (dentin substrate and titanium plate) of the adhesive system and water in normal and Grander-modified conditions was measured with a goniometer. Data were analyzed by ANOVA and Tukey test (5%). Results: Grander technology reduced the surface tension of water but not of the adhesive system Xeno III. The contact angle property of the adhesive ystem was not affected. Conclusion: Grander technology did not interfere with the surface tension and contact angle physical properties of the Xeno III self-etch adhesive system. Copyright: © 2011 Gonçalves et al.;.

Influence of Nd:YAG Laser on the Bond Strength of Self-etching and Conventional Adhesive Systems to Dental Hard Tissues

Purpose: The aim of this study was to investigate the influence of Nd:YAG laser on the shear bond strength to enamel and dentin of total and self-etch adhesives when the laser was applied over the adhesives, before they were photopolymerized, in an attempt to create a new bonding layer by dentin-adhesive melting.Material and Methods: One-hundred twenty bovine incisors were ground to obtain flat surfaces. Specimens were divided into two substrate groups (n=60): substrate E (enamel) and substrate D (dentin). Each substrate group was subdivided into four groups (n=15), according to the surface treatment accomplished: X (Xeno III self-etching adhesive, control), XL (Xeno III + laser Nd:YAG irradiation at 140 mJ/10 Hz for 60 seconds + photopolymerization, experimental), S (acid etching + Single Bond conventional adhesive, Control), and SL (acid etching + Single Bond + laser Nd:YAG at 140 mJ/10 Hz for 60 seconds + photopolymerization, experimental). The bonding area was delimited with 3-mm-diameter adhesive tape for the bonding procedures. Cylinders of composite were fabricated on the bonding area using a Teflon matrix. The teeth were stored in water at 37 degrees C/48 h and submitted to shear testing at a crosshead speed of 0.5 mm/min in a universal testing machine. Results were analyzed with three-way analysis of variance (ANOVA; substrate, adhesive, and treatment) and Tukey tests (alpha=0.05). ANOVA revealed significant differences for the substrate, adhesive system, and type of treatment: lased or unlased (p<0.05). The mean shear bond strength values (MPa) for the enamel groups were X=20.2 +/- 5.61, XL=23.6 +/- 4.92, S=20.8 +/- 4.55, SL=22.1 +/- 5.14 and for the dentin groups were X=14.1 +/- 7.51, XL=22.2 +/- 6.45, S=11.2 +/- 5.77, SL=15.9 +/- 3.61. For dentin, Xeno III self-etch adhesive showed significantly higher shear bond strength compared with Single Bond total-etch adhesive; Nd:YAG laser irradiation showed significantly higher shear bond strength compared with control (unlased).Conclusion: Nd:YAG laser application prior to photopolymerization of adhesive systems significantly increased the bond strength to dentin.

Influence of Concentration and Activation on Hydrogen Peroxide Diffusion through Dental Tissues In Vitro

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Direct Spectrometry: A New Alternative for Measuring the Fluorescence of Composite Resins and Dental Tissues

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Grander system: A new technology to reduce surface tension of adhesive systems in dentistry

Background. Reduced surface tension of liquids results in higher surface wetting ability and diffusivity by the substrate. Objectives. The objective of this study was to evaluate the influence of the Grander Technology in reducing the surface tension of adhesive systems. Methods. Two adhesive systems (self-etch and total-etch) were modified by physical contact with the Grander system Flexible unit to revitalize water, for 48 h. Surface tension of adhesive systems and water in normal and grander-modified conditions was measured with a goniometer. Results. The results showed a reduction of surface tension for all conditions grander-modified between 3-15%. Conclusions. Grander Technology was effective in reducing the surface tension of the Single Bond and Clearfil SE Bond adhesive systems. Clinical significance. Grander technology was employed to restructure the molecular structure of water-based adhesive systems, which can increase their wetness capacity and therefore ensure a greater diffusibility.

Estudo comparativo da eficacia de dois adesivos dentinarios e um cimento de ionomero de vidro empregados na adesão do amalgama a dentina

Pós-graduação em Odontologia Restauradora - ICT

Avaliação laboratorial da resistência ao cisalhamento de discos de porcelana e de um polímero de vidro cimentados à dentina bovina com o emprego de cimentos adesivos

Pós-graduação em Odontologia Restauradora - ICT

Influence of whitening gel application protocol on dental color change

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

The dramatic works of Gerhart Hauptmann /

(Vol. 8 translated by Willa and Edwin Muir.)

1991 update to 1989 Maine occupational wages in manufacturing industries /

Researched and compiled by Merrill Huhtala.

Market orientation, innovation capability and business performance:insights from the global financial crisis

Purpose - The paper aims to examine the role of market orientation (MO) and innovation capability in determining business performance during an economic upturn and downturn. Design/methodology/approach - The data comprise two national-level surveys conducted in Finland in 2008, representing an economic boom, and in 2010 when the global economic crisis had hit the Finnish market. Partial least square path analysis is used to test the potential mediating effect of innovation capability on the relationship between MO and business performance during economic boom and bust. Findings - The results show that innovation capability fully mediates the performance effects of a MO during an economic upturn, whereas the mediation is only partial during a downturn. Innovation capability also mediates the relationship between a customer orientation and business performance during an upturn, whereas the mediating effect culminates in a competitor orientation during a downturn. Thus, the role of innovation capability as a mediator between the individual market-orientation components varies along the business cycle. Originality/value - This paper is one of the first studies that empirically examine the impact of the economic cycle on the relationship between strategic marketing concepts, such as MO or innovation capability, and the firm's business performance.

Hyväntekeväisyyteen lahjoittavien käyttäytyminen ja siihen vaikuttavat tekijät. Tapaus: Suomen Evankelisluterilainen Kansanlähetys ry

Hyväntekeväisyysorganisaatiot tarvitsevat toimintansa rahoittamiseen lahjoittajia. Yksityishenkilöiden lahjoittamiskäyttäytymisen ymmärtäminen ja tunteminen on tärkeää, ja auttaa hyväntekeväisyysorganisaatioita markkinointitoimenpiteiden ja varainhankinnan suunnittelussa. Tämän tutkimuksen tarkoituksena on kuvata hyväntekeväisyyteen lahjoittavien lahjoittamiskäyttäytymistä sekä arvojen ja sosio-demografisten ominaisuuksien vaikutusta siihen. Tarkempi tutkimuskysymys on: miten lahjoittajan arvot ja sosio-demografiset ominaisuudet vaikuttavat lahjoittamiskäyttäytymiseen? Tutkimuskysymys sisältää kolme osa-ongelmaa: 1) Miten lahjoittamiskäyttäytymistä voidaan kuvata? 2) Miten lahjoittajan arvot vaikuttavat lahjoittamiskäyttäytymiseen? 3) Miten lahjoittajan sosio-demografiset ominaisuudet vaikuttavat lahjoittamiskäyttäytymiseen? Tutkimuksen tapausorganisaationa on Suomen Evankelisluterilainen Kansanlähetys ry. Tutkimuksen teoreettinen viitekehys rakentuu Sargeantin lahjoittajien käyttäytymisen mallista (1999) ja Schwartzin arvoteoriasta (1992) sekä aiemmasta tutkimuksesta lahjoittamiskäyttäytymisestä, arvoista ja sosio-demografisista ominaisuuksista. Teoriaosan lopuksi esitellään tutkimusmalli. Tutkimuksessa selitettävänä tekijänä on lahjoittamiskäyttäytyminen, joka määriteltiin neljän dimension mukaan: lahjoituskohde, lahjoitettu määrä, lahjoittamistiheys ja lahjoittamistapa. Selittävinä tekijöinä tarkastellaan Schwartzin arvoteorian mukaisia 56 yksittäistä arvoa, jotka tiivistyvät tässä tutkimuksessa yhdeksäksi arvoulottuvuudeksi: Itseohjautuvuus, virikkeisyys, mielihyvä, suoriutuminen, valta, turvallisuus, yhdenmukaisuus/perinteet, hyväntahtoisuus ja universalismi. Lisäksi selittävinä tekijöinä tarkastellaan sosio-demografisista ominaisuuksista sukupuolta, ikää, tuloja ja koulutusta. Tutkimuksen empiirinen osuus perustuu kvantitatiiviseen tutkimukseen. Aineisto kerättiin sähköisenä kyselytutkimuksena, joka oli esillä Kansanlähetyksen verkkosivuilla: suuressamukana.fi ja sekl.fi. Aineisto analysoitiin kvantitatiivisin menetelmin, käyttäen muun muassa ristiintaulukointia, khiin neliö –testiä ja yksisuuntaista varianssianalyysiä. Tulosten mukaan lahjoittajan arvomaailmalla oli vaikutusta lahjoittamiskäyttäytymiseen. Lahjoittajien tärkeimpinä pitämät arvoulottuvuudet olivat hyväntahtoisuus, turvallisuus, universalismi ja yhdenmukaisuus/perinteet. Vähiten tärkeänä pidettiin valtaa ja mielihyvää. Eri kohteisiin lahjoittavien, eri määrän lahjoittavien ja eri tiheydellä lahjoittavien kesken oli eroja kahden tai kolmen arvoulottuvuuden suhteen. Sosio-demografisista tekijöistä sukupuolella ja koulutuksella ei ollut vaikutusta lahjoittamiskäyttäytymiseen, mutta iällä ja tuloilla oli