Assessment of Marginal Adaptation Before and After Thermo-Mechanical Loading and Volumetric Shrinkage: Bulk Fill versus Conventional Composite / Evaluación de la Adaptación Marginal Antes y Después de la Carga Termomecánica y la Contracción Volumétrica: Relleno Bulk-Fill- versus Compuesto Convencional

ABSTRACT: The objective of the study was to evaluate marginal adaptation of Class II mesial-occlusal-distal (MOD) restorations before and after thermo-mechanical loading and volumetric shrinkage of the bulk-fill vs conventional composite resin. For marginal adaptation assessment, 24 Class II MOD cavities with cervical margins extending 1.0 mm below (distal) and 1.0 mm beyond (mesial) the cement-enamel junction were prepared in extracted human molars. The teeth were filled as follows: Group A - bulk-fill with SureFil SDR flow (first increment, 4 mm; second increment, 2 mm); Group B - bulk-fill with SureFil SDR flow as a base (first increment, 4 mm) and covered with the conventional nanohybrid composite Esthet-X HD (second increment, 2 mm); and Group C - incrementally filled with Esthet-X HD. Marginal adaptation was evaluated by scanning electron microscopy before and after thermomechanical loading (240,000 loading cycles and simultaneous 600 thermal cycles). To evaluate volumetric polymerization shrinkage, a semi-spherical mold was filled with the tested composites and placed in an AccuVol device after light curing. Both before and after loading, marginal adaptation in cervical dentin was superior (p < 0.05) for Groups A and B compared with Group C. In cervical enamel, Group B showed better marginal adaptation than Group C, and Group A presented intermediary results, between Groups B and C. Furthermore, bulk-fill flow resulted in greater shrinkage than Esthet-X HD. A significant improvement of marginal adaptation was observed when bulkfill flow was used instead of conventional composite resin both before and after thermomechanical loading. However, the bulk-fill flow presented higher volumetric polymerization shrinkage than the conventional composite.

RESUMEN: El objetivo de este trabajo consistió en evaluar la adaptación marginal de las restauraciones mesiales-oclusales-distales (MOD) de Clase II antes y después de la carga termo-mecánica y la contracción volumétrica de la carga compuesta de resina "bulk-fill" en comparación con resina convencional. Para la evaluación de adaptación, se prepararon 24 cavidades MOD de Clase II en molares humanos extraídos, los que se restauraron de la siguiente manera: Grupo A: restaurado con resina fluida Bulk-Fill SureFilSDR (primer incremento, 4 mm; segundo incremento, 2 mm); Grupo B: restaurado con resina fluida Bulk-Fill SureFil SDR (primer incremento, 4 mm) y cubierto con resina compuesta nanohíbrida Esthet-X HD (segundo incremento, 2 mm); y Grupo C - rellenado incrementalmente con Esthet-X HD. La adaptación marginal se evaluó mediante microscopía electrónica de barrido antes y después de la carga termomecánica (240.000 ciclos de carga y 600 ciclos térmicos simultáneos). Para evaluar la contracción volumétrica de la polimerización, se llenó un molde semiesférico con los compuestos probados y se colocó en un dispositivo AccuVol después del fotopolimerización. Tanto antes como después de la carga, la adaptación marginal en la dentina cervical fue superior (p <0,05) para los grupos A y B en comparación con el grupo C. En el esmalte cervical, el grupo B mostró una mejor adaptación marginal que el grupo C, y el grupo A presentó resultados intermedios, entre Grupos B y C. Se observó una mejora significativa de la adaptación marginal al utilizar la resina fluida Bulk-Fill en lugar de resina compuesta convencional tanto antes como después de la carga termomecánica. Sin embargo, la resina fluida 'Bulk-Fill' presentó una mayor contracción volumétrica de polimerización que el compuesto convencional.

Técnicas para reduzir os efeitos da contração de polimerização das resinas compostas fotoativadas / Techniques for reducing the effects of polymerization shrinkage of composites photoactivated resins

Introdução: uma complicação inerente a todas as resinas compostas é o stress gerado pela contração de polimerização. As resinas compostas da atualidade, após a polimerização, perdem entre 2% a 3% de todo o seu volume. Essa perda pode acarretar em alterações fortemente comprometedoras a nível micro e macroscópico. Objetivo: abordar a importância do uso de técnicas e manobras clínicas, que visam diminuir a contração de polimerização das resinas compostas, reduzindo seus efeitos na cavidade, para que se tenha um procedimento restaurador com elevado índice de sucesso clínico e boa aceitação pelos pacientes. Material e Métodos: foi realizada uma revisão da literatura por meio de uma busca bibliográfica nas seguintes bases de pesquisa online: PUBMED/MEDLINE, LILACS, BBO e SCIENCE DIRECT, através do rastreio de artigos relevantes publicados entre o período de 2000 a 2015. Resultados: comparando as formas de ativação dos compósitos, os compósitos fotopolimerizáveis possuem um menor escoamento e maior stress de contração se comparados a compósitos com ativação química, isso se dá devido à fotoativação que se destaca por ser uma reação rápida quando comparada a outros métodos, não dispondo de tempo para a resina se acomodar na cavidade e ter uma boa interação com o sistema adesivo previamente aplicado, levando a grande parte dos problemas clínicos das restaurações. Conclusão: questionamentos sobre os efeitos da contração de polimerização, ainda não foram completamente elucidados no meio científico, por isso algumas técnicas como a escolha de fotopolimerizadores a LED, manutenção da fase pré gel, manutenção do Fator C e técnica de inserção incremental, podem ser usadas para minimizar os efeitos dessa contração nas restaurações feitas com resina, afim de reduzir insucessos como, sensibilidade pós operatória, infiltração marginal e riscos de agressão pulpar levando a uma maior longevidade dos procedimentos restauradores com materiais resinosos. (AU)

Introduction: a complication inherent in all composite resins is the stress generated by the polymerization contraction. The present composite resins, after polymerization, lose between 2% and 3% of their entire volume. This loss can lead to strongly compromising micro and macroscopic changes. Objective: to address the importance of using technical and clinical maneuvers, which aim to reduce polymerization shrinkage of composite resins, reducing its effects in the cavity, in order to have a restorative procedure with high clinical success rate and good patient acceptance. Material and Methods: a review of the literature through a literature search in the following search online databases was performed: PubMed/MEDLINE, LILACS, BBO and SCIENCE DIRECT, through the screening of relevant articles published between 2000 to 2015. Results: comparing both activation of composites, the dental composites have a lower flow and higher stress of contraction compared to composites with chemical activation, this is the due to photoactivation that stands out for being a quick reaction when compared to other methods, not providing time for the resin to settle in well and have a good interaction with the previously applied adhesive system, leading to much of the clinical problems of restorations. Conclusion: questions about the effects of polymerization shrinkage have not been fully elucidated in the scientific community, so some techniques such as the choice of curing lights to LED, the pre gel phase maintenance, maintenance of Factor C and incremental insertion technique can It is used to minimize the effects of this contraction in restorations made with resin in order to reduce failures as post-operative sensitivity, microleakage and pulp assault risks leading to increased longevity of restorative procedures with resinous materials. (AU)

Influence of concentration, time and method of application of citric acid and sodium citrate in root conditioning

OBJECTIVES: The aim of this study was to establish the parameters of concentration, time and mode of application of citric acid and sodium citrate in relation to root conditioning. MATERIAL AND METHODS: A total of 495 samples were obtained and equally distributed among 11 groups (5 for testing different concentrations of citric acid, 5 for testing different concentrations of sodium citrate and 1 control group). After laboratorial processing, the samples were analyzed under scanning electron microscopy. A previously calibrated and blind examiner evaluated micrographs of the samples. Non-parametric statistical analysis was performed to analyze the data obtained. RESULTS: Brushing 25% citric acid for 3 min, promoted greater exposure of collagen fibers in comparison with the brushing of 1% citric acid for 1 minute and its topical application at 1% for 3 min. Sodium citrate exposed collagen fibers in a few number of samples. CONCLUSION: Despite the lack of statistical significance, better results for collagen exposure were obtained with brushing application of 25% citric acid for 3 min than with other application parameter. Sodium citrate produced a few number of samples with collagen exposure, so it is not indicated for root conditioning.

In-vivo evaluation of microleakage of nano-filled resin composite using two different restorative techniques

The study was carried out to evaluate and compare dentine margin microleakage of nano-filled resin composite restorations placed with a RMGIC using the co-cure technique and those placed with an 'all-in-one' self-etch DBA. In premolar teeth, that had to be extracted for orthodontic reasons, two proximal boxes with gingival margins placed in dentine were prepared. Restorations were inserted using co-cure method with RMGIC plus a nano-filled resin composite in one proximal box, and self-etch DBA plus nano-filled resin composite in other proximal box. After two weeks, teeth were extracted and was sectioned mesio-distally. The dye leakage length was measured using a stereomicroscope. The mean value of microleakage for co-cure technique was found to be lesser than that for all-in-one dentine bonding agent. Co-cure technique was found significantly superior to all-in-one DBA in its sealing ability at gingival margin

Uso de Ponta Diamantada Cvdentus para Preparo Cavitário em Dentes Decíduos: Estudo In Vivo / The Use of CVD Diamond Burs for Cavity Preparations in Primary Teeth: In Vivo Study

Objetivo: Comparar o uso de brocas convencionais usadas em micromotor e pontas diamantadas CVDentUS®para remoção de tecido cariado e realização do preparo cavitário, além de avaliar o comportamento das crianças durante o tratamento odontológico.Método: Foram selecionados para amostra 22 crianças de 36 a 60 meses, com atividade de cárie, apresentando no mínimo um molar decíduo com lesão de cárie ativa na superfície oclusal. Das 22 crianças, 60 molares decíduos com lesões de cárie incipiente fizeram parte da amostra selecionada para o estudo. A remoção do tecido cariado, o preparo cavitário e a restauração foram realizados em uma única sessão, sem anestesia local e sob isolamento relativo. Para a realização do preparo cavitário foram empregados dois tipos de sistemas: uma ponta diamantada CVDentUS®ou uma broca carbide. O critério de escolha do instrumental a ser utilizado em cada dente selecionado foi aleatório. Finalizado o preparo cavitário, os dentes foram restaurados com cimento de ionômero de vidro convencional. Para determinar o desempenho clínico de cada sistema, após cada sessão, os parâmetros visualização da área de trabalho (VAT), acesso á cavidade (AC), remoção do tecido cariado (RTC), e ruído e vibração (RV) foram avaliados pelo operador através dos escores: 1 û ruim, 2 û regular e 3 ûbom. Após o término de cada sessão, o comportamento das crianças (C) também foi avaliado.Resultados: Não houve diferença estatisticamente significante para o critério AC, entre os dois sistemas (p= 0,1033). Para os demais critérios, o CVDentUS® foi superior na VAT (p= 0,0001) e no RV (p= 0,0001), enquanto o Micromotor foi superior no RTC (p= 0,0265) e no C (p= 0,0169).Conclusão: O sistema CVDentUS® parece ser uma alternativa promissora, no entanto, são necessários estudos com amostras maiores para confirmar as características satisfatórias do sistema CVDentUS®

Objective: This study aims to compare the use of conventional handpiece and diamond burs CVDentus® system (CVD) for cavity preparation in children, evaluating their clinical performance and behavior during dental treatment. Method: The sample was selected with 22 children from 36 to 60 months with incipient caries on the occlusal surface of primary teeth. Of the 22 children, 60 primary molars with incipient caries lesions were part of the sample. The caries removal, cavity preparation and restoration were performed in a single session, without local anesthesia and under relative isolation. For the cavity preparation was used two types of systems: CVD or carbide bur. The teeth were restored with glass ionomer cement conventional after completed cavity preparation. The clinical performance of each system was determined, after each session, through the scores: 1 - poor 2 - and 3 regular û good to accessing the cavity, working area view, noise and vibration and removal of carious tissue. After the each session, the behavior of children was also analyzed. Results: No significant statistical difference was identified for accessing the cavity between the two systems (CVDentus® system and handpiece) (p = 0.1033). The CVD regarding the working area view (p = 0.0001), noise and vibration (p = 0.0001) was better than the handpiece, whilst the handpiece was better than CVDentus® system for removal of carious tissue (p = 0.0265) and behavior of the child (p = 0.0169). Conclusion: The CVD seems to be a promising alternative, however, further studies are needed in order to clarify aspects in the CVDentus® system

Perforaciones de las paredes radiculares en la preparación de las cavidades para alojar pernos metálicos en pacientes que acudieron a la Cátedra Integrada de la Facultad de Odontología de la Universidad Nacional de Asunción entre los años 2006 al 2009 / Perforations of the root walls in the preparation of the cavities to accommodate metal bolts in patients who attended the integrated Chair of the Faculty of Dentistry, National University of Asunción between 2006 to 2009

La perforación radicular se define como una lesión que comunica la cavidad pulpar con el ligamento periodontal o tejido óseo circundante que puede tener origen iatrogénico o patológico. En general las perforaciones iatrogénicas son provocadas durante la praxis del cirujano dentista; mientras que las patológicas proceden de caries y reabsorciones dentales. El objetivo de este estudio fue determinar la frecuencia de perforaciones de las paredes radiculares en preparaciones cavitarías para alojar pernos metálicos en pacientes que acudieron a la Cátedra de Clínica Integrada de la Facultad de Odontología de la Universidad Nacional de Asunción entre los años 2006 al 2009, por medio de un estudio observacional descriptivo de corte transversal, temporalmente retrospectivo. Los datos fueron extraídos de las fichas y radiografías panorámicas de los pacientes tratados de dicha cátedra. No teniendo conocimiento, hasta la fecha, de investigaciones sobre el tema de nuestro medio, se planteó este estudio en el que se encontró que 9 (8,3%) de 108 dientes con postes radiculares presentaban perforaciones, estando localizadas el 88,9% de las mismas en el tercio medio. En cuanto al tipo de poste según su fabricación, el 55,6% de los postes de las piezas dentarias peroradas eran coladas y 7 de ellos (78%) tenían más de un tercio de diámetro radicular en cervical. Se destaca la importancia del estudio radiográfico antes, durante y después de las preparaciones para alojar pernos metálicos a fin de evitar esta complicación, el fracaso de las restauraciones final y el mantenimiento de la pieza dentaria en la cavidad bucal.

Microleakage in conservative cavities varying the preparation method and surface treatment

OBJECTIVE: To assess microleakage in conservative class V cavities prepared with aluminum-oxide air abrasion or turbine and restored with self-etching or etch-and-rinse adhesive systems. Materials and Methods: Forty premolars were randomly assigned to 4 groups (I and II: air abrasion; III and IV: turbine) and class V cavities were prepared on the buccal surfaces. Conditioning approaches were: groups I/III - 37 percent phosphoric acid; groups II/IV - self-priming etchant (Tyrian-SPE). Cavities were restored with One Step Plus/Filtek Z250. After finishing, specimens were thermocycled, immersed in 50 percent silver nitrate, and serially sectioned. Microleakage at the occlusal and cervical interfaces was measured in mm and calculated by a software. Data were subjected to ANOVA and Tukey's test (α=0.05). RESULTS: Marginal seal provided by air abrasion was similar to high-speed handpiece, except for group I. There was SIGNIFICANT difference between enamel and dentin/cementum margins for to group I and II: air abrasion. The etch-and-rinse adhesive system promoted a better marginal seal. At enamel and dentin/cementum margins, the highest microleakage values were found in cavities treated with the self-etching adhesive system. At dentin/cementum margins, high-speed handpiece preparations associated with etch-and-rinse system provided the least dye penetration. CONCLUSION: Marginal seal of cavities prepared with aluminum-oxide air abrasion was different from that of conventionally prepared cavities, and the etch-and-rinse system promoted higher marginal seal at both enamel and dentin margins.

Effectiveness of intraoral suction systems and aspirating tips for evacuation of aluminum oxide particles during use of air-abrasion

Aim: The purpose of this study was to compare the effectiveness of a high-volume evacuation and a conventional intraoral suction system and aspirating tips for capturing aluminum oxide particles during use of an air-abrasion device. Methods: A phantom head was fixed at the dental chair head with secured a metallic device with 5 horizontal shafts, corresponding to operator’s clock related working positions, and one vertical shaft to simulate the operator’s nasal cavity. Petri plates were fixed to the shafts at distances of 20, 40 and 60 cm from the center of the oral cavity of the phantom head to collect the aluminum oxide particles spread over during air abrasion. The dust was aspirated with two types of suction tips used with both suction systems: a conventional saliva ejector and a saliva ejector customized by the adaptation of a 55-mm-diameter funnel. Results: The amount of particles showed that the greatest abrasive particle deposition occurred at a distance of 20 cm from the center of the oral cavity of the phantom head at 9 o’clock operatory position with the conventional saliva ejector attached to high-volume evacuation system. Conclusions: The greatest deposition of aluminum oxide particles occurred at the shortest distance between the operator and the center of the oral cavity, while using the high-volume evacuation system associated to the conventional suction tip.

Human teeth versus bovine teeth: cutting effectiveness of diamond burs

Aim: In this study, a mass-loss method was used to verify whether bovine enamel has the same wear pattern as human enamel in cutting efficiency tests of diamond burs. Methods: Seventy-two teeth were used: 36 human molars (HT) and 36 bovine mandibular central incisors (BT). The enamel of the teeth was cut using diamond bur #1092 attached to a high-speed handpiece under controlled pressure (50-80 g). Each bur (n=12) cut for a total of 72 min, divided into 6 periods of12 min each (12-min, 24-min, 36-min, 48-min, 60-min, and 72-min). The amount of enamel removed was determined by the difference between pre- and post-cut tooth masses. Results:The mean amounts (g) of enamel removed were: HT- 12-min=0.11; 24-min=0.12; 36-min=0.11; 48-min=0.11; 60-min=0.10; 72-min=0.12; BT- 12-min=0.12; 24-min=0.15; 36-min=0.15; 48-min=0.13; 60-min=0.16; 72-min=0.14. Data were analyzed using ANOVA followed by Tukey’s test, and the results showed statistically significant differences between human and bovine teeth (p<0.001) and among the cutting periods (p<0.001).Conclusions: It was concluded that the cutting efficiency of the burs was different between the tested substrates, and that bovine enamel underwent greater mass loss than did human enamel.

Influência da espessura de dentina, da constrição apical e do diâmetro do forame apical na precisão de leitura com localizadores foraminais eletrônicos / Influence of dentin thickness, apical constriction and diameter of the apical foramen in the accuracy of readings with electronic apex locators

Este trabalho teve como objetivo avaliar a influência da espessura de dentina radicular apical, da constrição apical e do diâmetro do forame apical na precisão de leituras realizadas com os localizadores foraminais eletrônicos Mini Apex Locator e Root ZX II®. Foram utilizados 30 incisivos inferiores permanentes unirradiculados de humanos, extraídos, com raízes íntegras e ápices completamente formados e portadores de um único canal. Por meio de um paquímetro, as espessuras radiculares dos dentes foram medidas, no sentido mésio-distal a 1,0 e a 4,0mm aquém do forame apical. Após a abertura coronária, uma lima tipo K no 10, munida de limitador de penetração, foi introduzida no canal radicular até que sua extremidade pudesse ser visualizada na altura do forame, com o auxílio de um microscópio óptico com aumento de 7,8X. Dessa medida, subtraiu-se 1,0mm, estabelecendo-se o comprimento de trabalho. A dilatação do canal radicular foi feita, inicialmente, com brocas de Gates Glidden, em ordem numérica decrescente, da número 5 até a número1, até 4,0mm aquém do forame apical. Os dentes foram fixados em um modelo experimental especialmente desenvolvido para permitir a medição com os localizadores foraminais eletrônicos. Tal modelo era constituído por dois segmentos de PVC: um de menor calibre, com diâmetro correspondente a meia polegada por 2,0cm de comprimento, com as duas extremidades abertas e outro, de maior calibre, com uma das extremidades fechada e com diâmetro interno equivalente ao diâmetro externo do primeiro segmento (3/4 de polegada). No segmento de maior diâmetro, foi feito um orifício lateral que permitiu o posicionamento do eletrodo labial do localizador foraminal eletrônico e, para a medição, no seu interior, foi colocado alginato e, então, encaixado o componente de menor diâmetro, fazendo com que o ápice radicular ficasse imerso no alginato. Foram realizadas as leituras com os localizadores, iniciando-se com a lima tipo K no 10 e seguindo-se...

This study evaluated the influence of the apical root dentin thickness, apical constriction and diameter of the apical foramen in the accuracy of readings obtained using the electronic apex locators Mini Apex Locator and Root ZX II ®. The study was conducted on 30 extracted human single-rooted permanent mandibular incisors, with intact and completely formed roots and presenting a single canal. The root thickness of the teeth was measured with a pachymeter in mesiodistal direction, at 1.0 and 4.0mm from the apical foramen. After coronal opening, a 10 K file with a stop was introduced in the root canal until its end could be observed at the level of the apical foramen, with aid of a light microscope with 7.8X magnification. One millimeter was subtracted from this measurement for establishment of the working length. Enlargement of the root canal was initially performed using Gates Glidden burs, in decreasing order, from number 5 to number 1, up to 4.0mm beyond the apical foramen. The teeth were fixated in an experimental model especially designed to allow the measurement with the electronic apex locators. This model was composed of two PVC segments: one smaller, with diameter corresponding to half inch with 2.0cm length, with both ends open; and the other, with larger diameter, with one end closed and internal diameter similar to the external diameter of the first segment (3/4 inch). In the segment with greater diameter, a lateral orifice was made to allow positioning of the lip electrode of the electronic apex locator. For the measurement, alginate was poured and the component with smaller diameter was fitted, so as the root apex was immersed in alginate. Readings were performed using the electronic apex locators, initiating with a 10 K file and following the sequence of instrumentation and measurement up to 130 K file. The 10 K file was used in all diameters. After this stage, the root canals were overinstrumented, i.e. the file tip was introduced until 1.0mm...

Influência da espessura de dentina, da constrição apical e do diâmetro do forame apical na precisão de leitura com localizadores foraminais eletrônicos / Influence of dentin thickness, apical constriction and diameter of the apical foramen in the accuracy of readings with electronic apex locators

Este trabalho teve como objetivo avaliar a influência da espessura de dentina radicular apical, da constrição apical e do diâmetro do forame apical na precisão de leituras realizadas com os localizadores foraminais eletrônicos Mini Apex Locator e Root ZX II®. Foram utilizados 30 incisivos inferiores permanentes unirradiculados de humanos, extraídos, com raízes íntegras e ápices completamente formados e portadores de um único canal. Por meio de um paquímetro, as espessuras radiculares dos dentes foram medidas, no sentido mésio-distal a 1,0 e a 4,0mm aquém do forame apical. Após a abertura coronária, uma lima tipo K no 10, munida de limitador de penetração, foi introduzida no canal radicular até que sua extremidade pudesse ser visualizada na altura do forame, com o auxílio de um microscópio óptico com aumento de 7,8X. Dessa medida, subtraiu-se 1,0mm, estabelecendo-se o comprimento de trabalho. A dilatação do canal radicular foi feita, inicialmente, com brocas de Gates Glidden, em ordem numérica decrescente, da número 5 até a número1, até 4,0mm aquém do forame apical. Os dentes foram fixados em um modelo experimental especialmente desenvolvido para permitir a medição com os localizadores foraminais eletrônicos. Tal modelo era constituído por dois segmentos de PVC: um de menor calibre, com diâmetro correspondente a meia polegada por 2,0cm de comprimento, com as duas extremidades abertas e outro, de maior calibre, com uma das extremidades fechada e com diâmetro interno equivalente ao diâmetro externo do primeiro segmento (3/4 de polegada). No segmento de maior diâmetro, foi feito um orifício lateral que permitiu o posicionamento do eletrodo labial do localizador foraminal eletrônico e, para a medição, no seu interior, foi colocado alginato e, então, encaixado o componente de menor diâmetro, fazendo com que o ápice radicular ficasse imerso no alginato. Foram realizadas as leituras com os localizadores, iniciando-se com a lima tipo K no 10 e seguindo-se...

This study evaluated the influence of the apical root dentin thickness, apical constriction and diameter of the apical foramen in the accuracy of readings obtained using the electronic apex locators Mini Apex Locator and Root ZX II ®. The study was conducted on 30 extracted human single-rooted permanent mandibular incisors, with intact and completely formed roots and presenting a single canal. The root thickness of the teeth was measured with a pachymeter in mesiodistal direction, at 1.0 and 4.0mm from the apical foramen. After coronal opening, a 10 K file with a stop was introduced in the root canal until its end could be observed at the level of the apical foramen, with aid of a light microscope with 7.8X magnification. One millimeter was subtracted from this measurement for establishment of the working length. Enlargement of the root canal was initially performed using Gates Glidden burs, in decreasing order, from number 5 to number 1, up to 4.0mm beyond the apical foramen. The teeth were fixated in an experimental model especially designed to allow the measurement with the electronic apex locators. This model was composed of two PVC segments: one smaller, with diameter corresponding to half inch with 2.0cm length, with both ends open; and the other, with larger diameter, with one end closed and internal diameter similar to the external diameter of the first segment (3/4 inch). In the segment with greater diameter, a lateral orifice was made to allow positioning of the lip electrode of the electronic apex locator. For the measurement, alginate was poured and the component with smaller diameter was fitted, so as the root apex was immersed in alginate. Readings were performed using the electronic apex locators, initiating with a 10 K file and following the sequence of instrumentation and measurement up to 130 K file. The 10 K file was used in all diameters. After this stage, the root canals were overinstrumented, i.e. the file tip was introduced until 1.0mm...

Influence of adhesive system and bevel preparation on fracture strength of teeth restored with composite resin

The aim of this study was to evaluate the fracture strength of teeth with different cavosurface margin cavity preparations and restored with composite resin and different adhesive systems. Eighty premolars were randomly divided in 8 groups, as follow: G1- sound teeth; G2- MOD preparation (no restoration); G3- Adper Single Bond without bevel preparation (butt joint); G4- Adper Single Bond with bevel preparation; G5- Adper Single Bond with chamfer preparation; G6- Clearfil SE Bond without bevel (butt joint); G7- Clearfil SE Bond with bevel preparation; G8- Clearfil SE Bond with chamfer preparation. The adhesive systems were applied according to manufacturers’ instructions. Composite resin (Filtek Z250) was incrementally placed in all cavities. After 24 h, the specimens were tested in a universal testing machine at a crosshead speed of 0.5 mm/min. Data were analyzed statistically by ANOVA and Tukey’s test (fracture strength) and Fisher’s exact test (fracture pattern). The confidence level was set at 95 percent for all tests. Prepared and non-restored teeth showed the worst performance and G4 exhibited the highest fracture strength among all groups (p<0.05). In conclusion, all restorative treatments were able to recover the fracture strength of non-restored teeth to levels similar to those of sound teeth. Using a total-etch adhesive system with bevel preparation significantly improved the resistance to fracture.

O objetivo deste estudo foi determinar, in vitro, a resistência à fratura de pré-molares superiores com diferentes preparos do ângulo cavossuperficial e restaurados com resina composta com distintos sistemas adesivos. Foram selecionados 80 dentes, divididos em 8 grupos: G1- hígidos; G2- preparos M.O.D.; G3- Single Bond sem bisel; G4- Single Bond com bisel reto; G5- Single Bond com bisel chanfrado; G6- Clearfil SE Bond sem bisel; G7- Clearfil SE Bond com bisel reto e G8- Clearfil SE Bond com bisel chanfrado. Os grupos 3-8 foram restaurados com resina composta Z250, pela técnica incremental. Os corpos-de-prova foram submetidos ao teste de resistência à fratura em máquina universal de ensaios, a uma velocidade de 0,5 mm/min. Os dados foram analisados estatisticamente pelos testes ANOVA, Tukey e exato de Fisher (α=0,05). O grupo 2 apresentou resistência inferior aos demais e o grupo 4 mostrou-se mais resistente à fratura do que os demais grupos (p<0,05). Concluiu-se que o bisel reto foi o preparo mais efetivo quando associado a adesivos dentinários com condicionamento ácido prévio. Ambos adesivos dentinários usados foram capazes de devolver a resistência perdida com o preparo cavitário.

Avaliação da qualidade de margem de preparos cavitários realizados com diferentes técnicas e instrumentos / Margin quality of cavity preparations with different techniques and instruments

Há mais de 50 anos, a Odontologia usa a mesma tecnologia para a preparação de cavidades, que é a alta velocidade com ponta diamantada e brocas carbides. Novos estudos e novas técnicas têm sido proporcionada para que haja uma opção a mais para esse procedimento no tratamento para os pacientes. Surgiram, então, novas tecnologias no mercado odontológico para eliminação mecânica da cárie e preparação de cavidades, como alta pressão de ar associado a jato de areia, aparelho de Laser, contra- ângulo multiplicador e ultrassom associado a pontas diamantadas. Mas por serem tecnologias novas, há ainda necessidade de pesquisas para a constatação de que realmente poderão vir a ser técnicas alternativas ou até substituir a tecnologia clássica que vem sendo utilizada com bons resultados. Assim, o propósito desta pesquisa foi avaliar, através de microscopia eletrônica de varredura (MEV), as margens cavitárias com e sem acabamento, realizadas com pontas diamantadas e CVDentus, associadas a diferentes tipos de dispositivos e mecanismo de ação. Os resultados encontrados mostraram não haver diferenças estatisticamente significantes (p < 0.05) entre as condições testadas, nas comparações individuais, com exceção dos grupos G4 x G7 (Alta velocidade+ Ponta Diamantada Preparo + Baixa Rotação + Ponta Diamantada para acabamento x Ultrassom + CVDentus Preparo 50% + Contra-ângulo). Concluiu-se que todas as formas de acabamento das margens cavitárias, testadas nesta pesquisa, são confiáveis e podem ser utilizadas. O uso do aparelho de ultrassom deve ser recomendado nas potências variando entre 50% a 75% para preparos cavitários.

For more than 40 years, dentistry has used the same technology for cavity preparation, high-speed rotation systems with diamond burs. New studies and techniques have been performed to develop a new treatment option for patients. Thus, new technologies have been possible such as high pressure sandblasting systems, laser devices, multiplying low-speed rotation, and finally, the ultra-sound with diamond burs. However, whether these new technologies can be an alternative or substitute for old practices with standard results is not known. The aim of this study was to evaluate by SEM cavity preparation margins with and without finishing, made by diamond burs and the CVDentus system associated to different devices and action forms. The results showed no statistically significant differences (p < .05) among the tested conditions on individual comparisons, except for GIV x GVII (highspeed rotation plus diamond bur + low-speed rotation plus diamond finishing bur x ultra-sound plus CVDentus 50% power plus low-speed rotation). It was concluded that all finishing modes on margin cavities are reliable and can be used in clinical practice. The use of the ultra-sound device can be recommended within 50-75% power for cavity preparations.

Pulpal temperature increase with high-speed handpiece, Er-YAG laser and ultrasound tips

The aim of this study was to compare intrapulpal temperature increase produced by high-speed handpiece, Er:YAG laser and CVDentus ultrasound tips during cavity preparation. Thirty bovine mandibular incisors with an enamel/dentin thickness of 4 mm at buccal surface had their roots amputated and were allocated to the following groups (n=10): Group I- high-speed handpiece; Group II- noncontact Er:YAG laser (250 mJ/4Hz); and Group III- CVDentus ultrasouns tips. All devices were used with water cooling. Class V cavities were prepared to a depth of 3.5 mm, measured with a periodontal probe. A type T thermocouple was placed inside the pulp chamber to determine the temperature increase (°C), which was recorded by a data acquisition system ADS 2000 IP (Lynx Technology) linked to a notebook computer. Data were analyzed statistically by oneway ANOVA and Tukey’s test (p=0.05). The mean temperature rises were: 1.10°C (±0.56) for Group I, 0.84°C (±0.55) for Group II, and 3.00°C (± 1.34) for Group III. There were no statistically significant differences (p>0.05) between Groups I and II, but both of them differed significantly from Group III (p<0.05). In conclusion, the use of Er:YAG laser and high-speed handpiece for cavity preparation resulted in similar temperature increase. Although ultrasound tips generated significantly higher intrapulpal temperature increase, it remained below the critical value of 5.5°C and may be considered safe for use.

Comparasion of two minimally invasive methods on the longevity of glass ionomer cement restorations: short-term results of a pilot study

The purpose of this study was to evaluate the clinical performance of glass ionomer cement (GIC) restorations comparing two minimally invasive methods in permanent teeth after 12 months. Fifty pregnant women (second trimester of pregnancy), mean age 22 ± 5.30 years, were treated by two previously trained operators. The treatment approaches tested were: chemomechanical method (CarisolvTM; MediTeam) and atraumatic restorative treatment (ART). A split-mouth study design was used in which the two treatments were randomly placed in 50 matched pairs of permanent teeth. The chemomechanical method (CM) was the test group and the ART was the control group. The treatments were performed in Public Health Centers. The tested restorative material was a high-strength GIC (Ketac Molar; 3M/ESPE). The restorations were placed according to the ART guidelines. Two calibrated independent examiners evaluated the restorations in accordance with ART criteria. The inter-examiner kappa was 0.97. Data were analyzed using 95 percent confidence interval on the binomial distribution and Fisher's exact test at 5 percent significance level. In a 12-month follow-up, 86 percent of the restorations were evaluated. In the test group (CM), 100 percent (CI=93.3-100 percent) of the restorations were considered successful. In the control group (ART) 97.6 percent (CI=87.4-99.9 percent) of the restorations were considered successful and 2.4 percent unsuccessful (marginal defect >0.5 mm). There was no statistically significant difference between the 12-mounth success rate for both groups (Fisher's exact test: P=0.49) and between the two operators (Fisher's exact test: P=1.00). Both minimally invasive methods, chemomechanical method and ART, showed a similar clinical performance after 12 months of follow up.

Avaliação morfológica do desgaste de instrumentos rotatórios e sua influência no selamento marginal de restaurações de resina composta: análise in vivo e in vitro / Morphologic evaluation of burs grinding and its influence on marginal sealing of composite resin restorations: an in vivo and vitro study

O objetivo desse estudo foi avaliar o desgaste de instrumentos rotatórios utilizados no preparo de Classe II in vivo e in vitro e sua influência no selamento marginal de restaurações de resina composta. Foram selecionados vinte pré-molares indicados para exodontia por motivos ortodônticos para cada estudo. Dividiram-se quatro grupos com cinco dentes cada, nos quais foram realizados preparos nas faces mesial e distal com duas pontas diamantadas convencionais, uma diamantada Chemical Vapor Deposition (CVD) e uma de carbeto de tungstênio. As cavidades foram restauradas com o sistema Scotchbond Multiuso Plus / Z100. Para o estudo in vivo, após 30 dias, foram feitas as exodontias e imersão em corante Rodhamina B a 0,2% (24 horas). Para o estudo in vitro, os espécimes foram termociclados (5e 55ºC - 1000 ciclos) e imersos no mesmo corante. Os espécimes foram secionados e avaliados em estereomicroscópio para avaliação da infiltração marginal, com atribuição de escores de zero a quatro. Realizou-se análise em microscopia eletrônica de varredura para visualização do desgaste das pontas e antes e após a confecção dos preparos. A aplicação do teste de Kruskal-Wallis (5%) não revelou diferença significante entre os grupos para os testes in vitro e in vivo. O teste de Mann Whitney demonstrou que os valores de infiltração marginal in vivo foram significantemente menores do que in vitro. Concluiu-se que não houve diferença significante na infiltração marginal das restaurações, independente do instrumento rotatório e que o teste in vivo levou a menor infiltração comparada ao teste in vitro. As pontas de diamante natural e a carbeto de tungstênio sofreram alterações severas com o uso e a ponta de diamante CVD apresentou menor evidência visual quanto ao desgaste.

Use of diagnodent® for diagnosis of non-cavitated occlusal dentin caries

The purpose of this study was to evaluate the use of a laser fluorescence device for detection of occlusal caries in permanent teeth. One hundred and ninety-nine non-cavitated teeth from 26 patients aged 10 to 13 years were selected. After dental prophylaxis, two previously calibrated dentists examined the teeth. Visual inspection, radiographic examination and laser measurements were performed under standardized conditions. The validation method was cavity preparation with a small cone-shaped diamond bur, when the two examiners agreed about the presence of dentin caries. It was found that the laser detection method produced high values of sensitivity (0.93) and specificity (0.75) and a moderate positive predictive value (0.63). The laser device showed the lowest value of likelihood ratio (3.68). Kappa coefficient showed good repeatability for all methods. Although the laser device had an acceptable performance, this equipment should be used as an adjunct method to visual inspection to avoid false positive results.

Effectiveness of high speed instrument and air abrasion on different dental substrates

The aim of this study was to compare the effectiveness of high speed (HS) and air abrasion (AA) instruments on groups of teeth (deciduous, permanent, bovine), in terms of preparation time, topography and presence of smear layer. Each group consisted of 5 teeth that had their buccal/lingual surfaces prepared by using either HS or AA. All procedures were standardized and timed. The teeth were then sectioned and prepared for evaluation of both the topography and the presence of smear layer by scanning electron microscopy. As regards preparation time, HS yielded preparations 1.5 times quicker than AA did on the three types of dental substrates (Wilcoxon test, p < 0.05). In both techniques (Kruskal-Wallis Test, p < 0.05) the preparation time was influenced by the dental substrate, particularly in deciduous teeth (Mann-Whitney test with Bonferoni's correction, p < 0.017), which required a longer preparation time. In the descriptive analysis of the topography, no difference was found between the substrates. Nonetheless, the different instruments used determined distinctive topographies. Both techniques produced a smear layer (÷2 McNemar, p > 0.05) in all substrates, but with different formations. In conclusion, the HS instrument was found to be more rapid than the AA. No difference was found between the three dental substrates as regards both the topography and the presence of smear layer. The differences found in the present study were only in relation to the effects of each instrument used.

Cavity preparation machine for the standardization of in vitro preparations

Several in vitro studies employ the confection of cavity preparations that are difficult to standardize by means of manual high speed handpieces. This study presents the development of a cavity preparation machine designed to standardize in vitro cavity preparations. A metal base of 25 mm x 25 mm x 4 mm (length x width x height) was coupled to a small mobile table which was designed to be able to move by means of two precision micrometers (0.01-mm accuracy) in the horizontal directions (right-left, and back-front). A high speed handpiece was coupled to a metallic connecting rod which had an accurate dial indicator enabling control of the vertical movement. The high speed handpiece is also able to move 180° around its longitudinal axis and 360° around its transversal axis. The suggested cavity preparation machine precisely helps in the standardization of cavity preparations for in vitro studies.

Various methods of caries removal in children: a comparative clinical study.

An in vivo study comparing the different methods of caries removal was done in children of age group 6-9 years. Among these patients a total number of 150 carious deciduous teeth were selected. Caries removal was done by hand instruments, airotor and carisolv. The efficacy, time taken and pain experienced by the patient during caries removal was evaluated. The results showed that airotor was the most efficient method (mean value 0.38), while carisolv was the least painful (mean value 0.080) and the most time consuming method (534.8 seconds).