Does laser diode irradiation improve the degree of conversion of simplified dentin bonding systems?

Abstract Simplified dentin-bonding systems are clinically employed for most adhesive procedures, and they are prone to hydrolytic degradation. Objective This study aimed to investigate the effect of laser diode irradiation on the degree of conversion (DC), water sorption (WS), and water solubility (WSB) of these bonding systems in an attempt to improve their physico-mechanical resistance. Material and Methods Two bonding agents were tested: a two-step total-etch system [Adper™ Single Bond 2, 3M ESPE (SB)] and a universal system [Adper™ Single Bond Universal, 3M ESPE (SU)]. Square-shaped specimens were prepared and assigned into 4 groups (n=5): SB and SU (control groups - no laser irradiation) and SB-L and SU-L [SB and SU laser (L) - irradiated groups]. DC was assessed using Fourier transform infrared spectroscopy with attenuated total reflectance. Additional uncured resin samples (≈3.0 µL, n=5) of each adhesive were also scanned for final DC calculation. For WS/WSB tests, similar specimens (n=10) were prepared and measured by monitoring the mass changes after dehydration/water storage cycles. For both tests, adhesive fluids were dropped into standardized Teflon molds (6.0×6.0×1.0 mm), irradiated with a 970-nm laser diode, and then polymerized with an LED-curing unit (1 W/cm2). Results Laser irradiation immediately before photopolymerization increased the DC (%) of the tested adhesives: SB-L>SB>SU-L>SU. For WS/WSB (μg/mm3), only the dentin bonding system (DBS) was a significant factor (p<0.05): SB>SU. Conclusion Irradiation with a laser diode improved the degree of conversion of all tested simplified dentin bonding systems, with no impact on water sorption and solubility.

Evaluation of temperature increase during in-office bleaching

ABSTRACT The use of light sources in the bleaching process reduces the time required and promotes satisfactory results. However, these light sources can cause an increase in the pulp temperature. Objective The purpose of the present study was to measure the increase in intrapulpal temperature induced by different light-activated bleaching procedures with and without the use of a bleaching gel. Material and Methods A human maxillary central incisor was sectioned 2 mm below the cementoenamel junction. A K-type thermocouple probe was introduced into the pulp chamber. A 35% hydrogen peroxide bleaching gel was applied to the vestibular tooth surface. The light units used were a conventional halogen, a hybrid light (only LED and LED/Laser), a high intensity LED, and a green LED light. Temperature increase values were compared by two-way ANOVA and Tukey´s tests (p<0.05). Results There were statistically significant differences in temperature increases between the different light sources used and between the same light sources with and without the use of a bleaching gel. The presence of a bleaching gel generated an increase in intra-pulpal temperature in groups activated with halogen light, hybrid light, and high intensity LED. Compared to the other light sources, the conventional halogen lamp applied over the bleaching gel induced a significant increase in temperature (3.83±0.41°C). The green LED unit with and without gel application did not produce any significant intrapulpal temperature variations. Conclusion In the present study, the conventional halogen lamp caused the highest increase in intrapulpal temperature, and the green LED caused the least. There was an increase in temperature with all lights tested and the maximum temperature remained below the critical level (5.5°C). The addition of a bleaching gel led to a higher increase in intrapulpal temperatures.

Remoção de pigmentação melânica gengival por meio de dermoabrasão û relato de caso / Elimination of gingival melanin pigmentation through dermabrasion û case report

A pigmentação melânica gengival é uma condição clínica mais prevalente em indivíduos da raça negra e oriental, consistindo frequentemente em um problema estético. Embora a recidiva seja imprevisível, vários tratamentos são propostos, entre eles a mucodermoabrasão com diferentes instrumentos. O objetivo do presente relato de caso clínico foi demonstrar duas técnicas para resolução desses casos: emprego dos gengivótomos e de uma ponta de cerâmica em alta rotação.

Gingival melanin pigmentation is a clinical condition, more prevalent in oriental and black people, and may generate esthetical problems. Despite the fact that recurrence is unpredictable, different treatments are proposed, such as epithelial abrasion with different instruments. The objective of the present case report is to show two different techniques for resolution of such cases: use of Kirkland periodontal knife, and abrasive ceramic burs in high speed.

Endocrown: a conservative approach / Endocrown: uma abordagem conservadora

The purpose of this clinical case description article was to present the planning sequence, indication, treatment and performance to obtain a crown of the Endocrown type. This clinical case description article illustrates a therapeutic option for functional and esthetic rehabilitation of a devitalized mandibular molar, presenting a small amount of remaining coronal tooth structure, by means of cementing a pure porcelain crown of the Endocrowntype (Adhesive Endodontic Crown). A 39-year-oldwoman presented to the Graduate clinic of the Bauru Dental School (FOB), University of São Paulo (USP),with the complaint that tooth #36 had an extensive and unsatisfactory composite resin restoration. The lithium disilicate-based system of monolithic porcelain was used with the lost wax technique. This therapy promoted the stability and retention of the indirect restoration, without the need for performing reconstruction of the above mentioned tooth, either by means of a cast metal core or reconstruction with intracanal post, there by reducing the treatment time. After the tooth preparation, the provisional restoration was done with acrylic resin to determine if the retention and stability of the remaining tooth was adequate to receive the indirect. The characteristics of the internal and external walls of the dental remnants, cervical termination, impression-taking, laboratory stages and adhesive cementation will be discussed. The major advantage of indicating an endocrown is the use of the dental remnants it self, particularly the pulp chamber, to promote retention and stability in cases without adequate height for performing complete dental and crown reconstruction...

O objetivo deste artigo de descrição de caso clínico foi apresentar a sequência de planejamento, indicação, tratamento e execução de uma coroa do tipo Endocrown (Coroa Endodôntica Adesiva).Este artigo ilustra uma opção terapêutica para reabilitação funcional e estética de um molar inferior desvitalizado, apresentando uma pequena quantidade de remanescente coronário, por meio da cimentação de uma coroa pura de porcelana do tipo Endocrown. Uma mulher de 39 anos de idade, apresentou-se à clínica de Pós-Graduação da Faculdade de Odontologia de Bauru (FOB) da Universidade de São Paulo(USP), com a queixa de uma extensa e insatisfatória restauração de resina composta no dente 36. O sistema monolítico de porcelana à base de dissilicato de lítio foi utilizado com a técnica da cera perdida.Esta técnica promoveu a estabilidade e a retenção da restauração indireta, sem a necessidade de realizara reconstrução do dente 36, quer por meio de um núcleo metálico fundido ou reconstrução com pino intra canal, reduzindo assim o tempo de tratamento.Após o preparo do dente, realizou-se a restauração provisória com resina acrílica e verificou-se se a retenção e estabilidade do remanescente dentário era adequada para receber a restauração do tipo Endocrown. As características das paredes internas e externas do preparo do remanescente dentário,término cervical, moldagem, etapas laboratoriais e de cimentação são discutidas. A principal vantagem da indicação de uma coroa do tipo Endocrown é a utilização do próprio remanescente dentário,particularmente a câmara pulpar, para promover a retenção e estabilidade em casos onde não haja altura adequada para a reconstrução coronária...

Curing depth of a silorane-based resin composite

Introduction: The silorane-based resin appears aiming to minimize the effects of polymerization shrinkage, but other properties must be studied. Objective: To evaluate the polymerization depth of two composites with different organic matrix. Material and methods: 80 cylindrical specimens were prepared using a metallic matrix, with three layers (top, middle and bottom), 1 mm high and 5 mm in diameter. The specimens were divided into eight groups (n = 10) according to the composite resins: Filtek P90 (3M/ESPE); Filtek Z250 (3M/ESPE), light-cured with a LED device with different irradiance and times (600mW/cm2 x 40s, 1000mW/cm2 x 40s, 1000mW/cm2 x 20s; 1400mW/cm2 x 20s). The irradiance was controlled by placing plastic rings coupled to the device's tip. Immediately after polymerization, the specimens' layers were separated and five Knoop microhardness readings (initial hardness) were performed on each one of the four layers (0, 1, 2, and 3 mm). After 7 day storage in water at 37ºC, new readings were performed (final microhardness). The data were analyzed by four-way ANOVA (resin, energy density, depth and time) and Tukey test (α = 0.05). Results: The microhardness decreased with the depth increasing both in the initial and 7 day readings. The hardness increased with the highest power densities. The resin P90 had lower hardness values. Conclusion: The silorane-based resin showed Knoop microhardness values significant smaller than those of methacrylate-based resin in almost all evaluated parameters. However, both presented similar behaviors in relation to the curing depth.

Tratamento estético de diastemas múltiplos com facetas pelo sistema CAD-CAM / Aesthetic rehabilitation of multiple diastemas using veneers produced through CAD-CAM system

Facetas minimamente invasivas, também conhecidas como ôlentes de contatoõ, têm sido consideradas uma alternativa interessante para tratar problemas estéticos nos dentes anteriores. O presente relato de caso descreve passo a passo o tratamento de diastemas múltiplos com facetas minimamente invasivas, e discute tópicos importantes relacionados a este assunto quanto a indicações, materiais utilizados e longevidade destes tipos de restaurações...

Minimally invasive veneers, also known as ôcontact lensesõ, are being considered an interesting alternative for aesthetic rehabilitation of anterior teeth. This case report describes, step by the step the treatment of multiple diastemas with minimally invasive veneers, and addresses important issues related to this topic concerning indications, materials and longevity of these type of restorations...

Intra pulp chamber temperature variation caused by Nd: YAG and Diode LASER irradiation / Variação da temperatura intracâmara pulpar provocada pela irradiação com laser de Diodo e Nd: YAG

A irradiação com LASER de Neodímio (Nd:YAG) e de Diodo sobre sistemas adesivos pode aumentar a resistência de união em dentina, no entanto a existe a preocupação com a variação de temperatura intracâmara pulpar. O objetivo deste trabalho foi avaliar a variação da temperatura intracâmara pulpar após a aplicação dos sistemas adesivos e subsequente a irradiação com LASER de diodo e Nd:YAG. Material e Métodos: Este estudo apresentou um desenho experimental fatorial com dois fatores: LASER em dois níveis (Diodo [D] e Nd:YAG [N]) e sistema adesivo em quatro níveis (Adper™ Scotchbond™ Multi-Purpose [MP], Adper™ SingleBond 2 [SB], Clearfil™ SE Bond [CSE] e Adper™ Easy One [EO]). A variável de resposta quantitativa foi a variação da temperatura (∆t) em ºC .Utilizou-se 40 dentes bovinos, separados em 8 grupos (n=5), a superfície vestibular foi desgastada até 1 mm de espessura. Depois da aplicação de cada sistema adesivo, mas previamente a fotopolimerização, os espécimes eram irradiados com LASER de diodo e Nd:YAG com parâmetro padronizados. A ∆t foi obtida com um termopar inserido intracâmara pulpar. Os valores obtidos foram submetidos ao teste ANOVA a 2 critérios seguido de Tukey para comparações individuais(p<0,05). Resultados: A média e o desvio padrão da ∆t obtidos foram: N-MP: 12.60 (± 2.51), N-SB: 10.40 (± 5.03), N-CSE: 11.80 (± 5.12) e N-EO: 10.20 (± 2.39), D-MP: 4.4 (± 1.82), D-SB: 5.20 (± 1.54), D-CSE: 4.60 (± 1.14), D-EO: 3.60 (± 1.52). Conclusão: O tipo de sistema adesivo não foi significante no aquecimento gerado pela irradiação com LASER, mas o LASER de Nd:YAG pode fornecer um potencial maior para causar danos a pulpar...

Neodymium (Nd:YAG) and Diode LASER irradiation on adhesive systems canincrease bond strength to dentin, however, concerns about the temperature variation inside pulp chamber still remain. The aim of this study was to evaluate the intra pulp chamber temperature variation caused by irradiation with Nd:YAG or Diode LASER on different adhesive systems. Material and Methods: This study presented experimental design with two factors: LASER on two levels (Diode [D] and Nd:YAG [N]) and adhesive system on four levels (Adper™ Scotchbond™ Multi-Purpose [MP], Adper™ SingleBond 2 [SB], Clearfil™ SE Bond [CSE] and Adper™ Easy One [EO]). The quantitative response variable was the temperature variation (∆t) in ºC. Forty bovine teeth, distributed into 8 groups (n = 5), had the buccal surface flattened up to1 mm thickness of dentin. After the application of each adhesive system, but previously to the light curing, specimens were irradiated with Nd:YAG or Diode LASER with standardized parameters. The ∆t was obtained through a thermocouple inserted into pulp chamber. The values of ∆t were submitted to two-way ANOVA, followed by Tukey (p < 0.05) for individual comparisons. Results: The means (± standard deviation) of ∆t were: N-MP: 12.60 (± 2.51), N-SB: 10.40 (± 5.03), N-CSE: 11.80 (± 5.12) and N-EO: 10.20 (± 2.39), D-MP: 4.4 (± 1.82), D-SB: 5.20 (± 1.54), D-CSE: 4.60 (± 1.14), D-EO: 3.60 (± 1.52). Conclusion: The type of adhesive system was not significant in temperature changes generated by LASER irradiation, but Nd:YAG LASER may provide a higher potential to cause pulp damage...

Diode laser irradiation increases microtensile bond strength of dentin

Laser irradiation after the immediate application of dentin bonding systems (DBSs) and prior to their polymerization has been proposed to increase bond strength. The objective of this study was to evaluate the effect of diode laser irradiation (λ = 970 nm) on simplified DBSs through microtensile bond strength tests. Forty healthy human molars were randomly distributed among four groups (n = 10) according to DBSs used [Adper™ SingleBond 2 (SB) and Adper™ EasyOne (EO)], and the respective groups were irradiated with a diode laser (SB-L and EO-L). After bonding procedures and composite resin build-ups, teeth were stored in deionized water for 7 days and then sectioned to obtain stick-shaped specimens (1.0 mm2). The microtensile test was performed at 0.5 mm/min, yielding bond strength values in MPa, which were evaluated by two-way ANOVA followed by Tukey’s test (p < 0.05) for individual comparisons. For both adhesive systems, diode laser irradiation promoted significant increases in bond strength values (SB: 33.49 ± 6.77; SB-L: 43.69 ± 8.15; EO: 19.67 ± 5.86; EO-L: 29.87 ± 6.98). These results suggest that diode laser irradiation is a promising technique for achieving better performance of adhesive systems on dentin.

How erosive drinks and enzyme inhibitors impact bond strength to dentin

Concern has been raised about the bonding of restorative procedures to an erosive lesion, given the change in organic and inorganic composition and structure of this substrate. This in vitro study evaluated the effect of erosive drinks and an enzyme inhibitor (2% chlorhexidine digluconate – 2% CHX) on bond strength to dentin. Sixty sound human third molars were selected, and the occlusal enamel was flattened, exposing the dentin surface. The specimens were randomly divided into three groups: AS-Artificial saliva (control group), RC- Regular Cola and ZC- Zero Cola. Twenty specimens were immersed in their respective solution for 1 minute, 3 times a day, over the course of 5 days. After acid etching and before bonding with Adper Single Bond 2, half of the samples of each group (n = 10) were treated with 2% CHX, whereas the other half (n = 10) were not, forming the control group (CONV). All the specimens were restored with Filtek Z250 composite resin filled in Tygon tubes (0.48 mm2), yielding six microcylinders for microshear bond strength testing. Three composite resin microcylinders of each specimen were tested after 1 month, and the remaining microcylinders were tested after 6 months. Failure modes were determined using a stereomicroscope (40x). The data were statistically analyzed by three-way ANOVA and Tukey tests (α = 0.05). Overall bonding was reduced after 6 months, regardless of treatment. The 2% CHX enhanced bond strength after 1 month only in the ZC group, and did not enhance bonding performance to demineralized dentin by erosive protocol after 6 months in any group.

Surface roughness and wear of resin cements after toothbrush abrasion

Increased surface roughness and wear of resin cements may cause failure of indirect restorations. The aim of this study was to evaluate quantitatively the surface roughness change and the vertical wear of four resin cements subjected to mechanical toothbrushing abrasion. Ten rectangular specimens (15 × 5 × 4 mm) were fabricated according to manufacturer instructions for each group (n = 10): Nexus 3, Kerr (NX3); RelyX ARC, 3M ESPE (ARC); RelyX U100, 3M ESPE (U100); and Variolink II, Ivoclar/Vivadent (VL2). Initial roughness (Ra, µm) was obtained through 5 readings with a roughness meter. Specimens were then subjected to toothbrushing abrasion (100,000 cycles), and further evaluation was conducted for final roughness. Vertical wear (µm) was quantified by 3 readings of the real profile between control and brushed surfaces. Data were subjected to analysis of variance, followed by Tukey’s test (p < 0.05). The Pearson correlation test was performed between the surface roughness change and wear (p < 0.05). The mean values of initial/final roughness (Ra, µm)/wear (µm) were as follows: NX3 (0.078/0.127/23.175); ARC (0.086/0.246/20.263); U100 (0.296/0.589/16.952); and VL2 (0.313/0.512/22.876). Toothbrushing abrasion increased surface roughness and wear of all resin cements tested, although no correlation was found between those variables. Vertical wear was similar among groups; however, it was considered high and may lead to gap formation in indirect restorations.

Orthodontic treatment finishing with minimally invasive resin composite veneers / Finalização de tratamento ortodôntico facetas de resina composta minimamente invasivas

Anatomic alterations caused by incisal guide wear, even when small, can cause the aspect of an aged smile. The objective of this clinical case is to reporta highly conservative esthetic treatment performed through the association of in-office bleaching andresin composite veneers. In-office bleaching was performed with 35% hydrogen peroxide, and in the following week, minimal invasive resin composite veneers were installed on the upper incisors and canines. In the next appointment, finishing and polishing were performed with abrasive discs and silicon carbide brushes. The results were considered highly satisfactory, establishing a younger aspectof the patient’s smile. Resin composite veneers are still an excellent alternative for esthetic reanatomizationof anterior teeth, capable of generating optimal results with low costs and time...

Alterações anatômicas causadas pelo desgaste da guia incisal, mesmo quando pequeno, podem causar um aspecto de um sorriso envelhecido. O objetivo deste caso clínico é reportar uma tratamento estético altamente conservativo realizado por meio da associação de clareamento em consultório e facetas de resina composta. O clareamento em consultório foi realizado com peróxido de hidrogênio a 35%,e na semana seguinte, facetas de resina composta minimamente invasivas foram instaladas nos incisivos e caninos superiores. Na próxima consulta, acabamento e polimento foram realizados com discos abrasivos e escova de carbeto de silício. Os resultados foram considerados altamente satisfatórios, estabelecendo um aspecto jovial ao sorriso da paciente. Facetas de resinas compostas são ainda uma excelente alternativa para reanatomização estética dos dentes anteriores, capazes de gerar resultados ótimos com baixo custo e tempo...

Multidisciplinary esthetic approach for multiple anterior diastema: 36-month clinical performance / Abordagem estética multidisciplinar para múltiplos diastemas anteriores: desempenho clínico de 36 meses

The presence of diastema, between anterior teeth, distorts a pleasing smile by concentrating the observer’s attention on the spaces. The patient’s needs and expectations must be considered in the process of treatment planning to ensure satisfaction with the treatment out comes. There are many forms of therapy that can be used for diastema closure. A carefully developed diagnosis, which includes a determination of the causal element sand advanced treatment planning, allows the mostappropriate treatment to be selected for each case. The aim of this paper is to present a multidisciplinary approach as a solution to multiple diastemata in the anterior region using gingival tissue recontouring and direct adhesive restorations, with minimumwear of the dental structure, after the orthodontic intervention, discussing the minimal intervention toobtain imperceptive and aesthetic final restoration. Thirty-six months after the treatment was carriedout, the final aesthetic was maintained with all dental element details and gingival tissue harmony, without recurrence of periodontal pockets and the preservation of the tooth color and shape...

A presença de diastemas, entre dentes anteriores, distorce um sorriso agradável, concentrando a atenção do observador para os espaços. As necessidades e expectativas do paciente devem ser consideradas no processo de planejamento para garantir a satisfação no resultado do tratamento. Existem muitas formas de tratamento que podem ser utilizadas para o fechamento de diastemas. Um diagnóstico desenvolvido cuidadosamente, que inclui a determinação dos elementos causais e planejamento avançado do tratamento, permite as eleção do tratamento mais adequado para cada caso. O objetivo deste artigo é apresentar uma abordagem multidisciplinar como solução para diastemas multiplos na região anterior usando o recontorno gengival e restaurações adesivas diretas, com mínimo desgaste da estrutura dental, após a intervenção ortodôntica discutindo a intervenção mínima para a obtenção de restaurações finais estéticas e imperceptiveis. Trinta e seis meses após o tratamento foi avaliado, a estética final foi mantida com os detalhes do elemento dental e harmonia tecido gengival, sem recorrência de bolsas periodontais e preservando a cor e forma dos dentes...

Influence of temporary cement in the tensile strenght of fullcrowns cemented with resin cement / Influência do cimento temporário na resistência à tração de coroas totais cimentadas com cimento resinoso

Objetivo: Este estudo avaliou a influência do eugenol residual a resistência à tração na cimentação decoroas cerômero, usando cimento resinoso. Material e Métodos: Trinta e nove terceiros molares foram preparados para coroa total. Para cada dente preparado uma restauração provisória e uma coroa de cerômero foram feitas. Os dentes foram divididos em três grupos de acordo com o cimento provisório (n = 13): [GTB]Temp de Bond; [GTBNE] Temp NE Bond e [GDY] Dycal. Após a cimentação temporária, os dentes foram mantidos em água destilada por uma semana e, em seguida, submetidos ao teste de tração em uma máquina universal de ensaios (EMIC DL 500), usando uma célula de carga 200 kgf em 0,5 mm/min. Após o teste, os dentes foram limpos e receberam a cimentação adesiva final das coroas de cerômero. Em seguida, as amostras foram mantidas em água destilada (37 ºC) durante uma semana e, em seguida, foi realizado o teste de resistência à tração, também a 0,5 mm/ min. A comparação entre grupos foi realizada por análise de variância (ANOVA)seguida pelo teste de Tukey (p < 0,05). Resultados: Os resultados (kgf) de cimentação provisória para grupos GTB, GTBNE e GDY foram respectivamente: 2,75 ± (1.35b), 3,43 ± (1.66ab), e 4,48 ± (1.11a).Os resultados da cimentação adesiva (Kgf) eram respectivamente: 42,71 ± (15.33b), 57,59 ± (15.66a),e 54,75 ± (15.28ab). Conclusão: Concluiu-se que o cimento temporário, contendo eugenol apresentou influência negativa sobre a resistência à remoção de coroas cimentados com cimento de resinoso. Além disso, o dycal apresentou melhor resistência à remoção.

Objectives: This study evaluated the influenceof residual eugenol on the tensile strength in the ceromer crowns cementation, using resin cement. Material and Methods: Thirty-nine third molarswere prepared for a full crown. For each prepared tooth one provisional and one ceromer crown were made. The teeth were divided into three groups according the temporary cement (n = 13): [GT]Temp Bond; [GTBNE] Temp Bond NE and [GDY]Dycal. After temporary cementation, the teeth were kept in distilled water for one week and then submitted to traction test in a universal testing machine (EMIC DL 500), using a 200 Kgf loadcell at 0.5 mm/min. After the test, the teeth werecleaned and received the final adhesive cementationof ceromer crowns. Next, the specimens were keptin distilled water (37 0C) for a week and then the tensile strength test was performed, also at 0.5 mm/min. The comparison among groups was carriedout by variance analysis (ANOVA) followed by theTukey test (p ≤ 0.05). Results: The results (Kgf)of provisional cementation for groups GTB, GTBNEand GDY were respectively: 2.75 ± (1.35b), 3.43± (1.66ab), and 4.48 ± (1.11a). The results of the adhesive cementation (Kgf) were respectively:42.71 ± (15.33b), 57.59 ± (15.66a), and 54.75 ±(15.28ab). Conclusion: It was concluded that the temporary cement containing eugenol presented negative influence on the removal resistance of crowns cemented with resin cement. Furthermore,dycal presented best result for removal resistance.

Abordagem multidisciplinar na restauração de um dente posterior extensamente destruído - relato de caso / Extensive posterior tooth restoration with a multidisciplinary approach - case report

Entre os tipos mais frequentes de restaurações dentárias, destacam-se as restaurações dos tipos compostas e/ou complexas em dentes posteriores, sendo comum a perda de uma ou mais cúspides, necessitando de uma abordagem multidisciplinar. No contexto atual da Odontologia minimamente invasiva, as resinas compostas têm destaque importante, pois possibilitam a substituição de restaurações insatisfatórias sem sacrificar excessivamente as estruturas dentárias sadias. Esta característica importante permite a realização de restaurações extensas em dentes desvitalizados. Este relato de caso clínico objetiva descrever uma técnica restauradora de um dente posterior envolvendo uma abordagem multidisciplinar (periodontia, endodontia e dentística restauradora), apresentando e discutindo a sequência dos procedimentos adotados. Neste caso clínico foi realizada uma cirurgia periodontal com intuito de possibilitar a posterior restauração direta em resina composta, associada a um retentor intrarradicular reforçado com fibra de vidro. Dessa forma, com a evolução das técnicas e materiais disponíveis para os clínicos gerais e especialistas, esta abordagem possibilita a devolução da estética e da função em um pequeno número de sessões clínicas, com custo reduzido quando comparado aos tratamentos restauradores indiretos.

Complex or composite posterior teeth restorations are among the most common types, and the loss of one or more cuspids is very frequent and often requires a multidisciplinary approach. Within the context of minimally invasive Dentistry, composite resins are widely used since they allow the replacement of unsatisfactory restorations, avoiding excessive wear of the healthy tooth structure. This enables extensive restorations in devitalized teeth. This report aims to describe a restoration technique applied on a posterior tooth through multidisciplinary approach (periodontics, endodontics and restorative dentistry), presenting and discussing the adopted procedures. In this clinical case, a periodontal surgery was performed in order to allow the subsequent direct composite resin restoration associated with an intra-radicular fiber post. Thus, with the evolution of techniques and materials available to the general practitioner and specialists, direct restorations allow aesthetical and functional restoration with a small number of clinical sessions with a lower cost when compared to indirect restorations.

Evaluation of dentinal permeability reduction provided by different desensitizing treatments

problem at dental offices and new approaches may be developed. Objectives: The authors studied different desensitizing treatments and their efficacy in reducing dentinal permeability and dentinal tubules opening. Material and methods: One hundred bovine incisors roots had their buccal surface flattened and treated by 3 applications of each desensitizing agent, following the respective groups (n = 10). After treated, 7 specimens of each group were prepared for a 0.5% basic fuchsin permeability test and the other 3 specimens were prepared to SEM qualitative analysis. The permeability test specimens were sectioned with a diamond saw in order to evaluate the stained and unstained areas. Kruskall Wallis statistical analysis was performed (p < 0.05). Results: Colgate Pró-Alívio paste and toothpaste, diode and Nd:YAG Lasers, GHF, Sensi Active, Oxagel and 2% Desensibilize promoted a significant permeability reduction when compared with the respective control groups (p < 0.05). Comparing the mean permeability differences between the different groups after the treatments, Oxagel and Nd:YAG were better than 0.2% Desensibilize group. Conclusion: None of the treatments may be considered 100% effective in treating dentinal hypersensitivity since a partial reduction of the permeability was observed.

Use of restorative materials for direct and indirect restorations in posterior teeth by Brazilian dentists

Introduction: Often, dentists perform procedures aiming at more esthetical than long-term clinical performance of restorations. Objective: To evaluate the prevalence of use of different direct and indirect restorative materials in posterior teeth. Material and methods: In 2004, a questionnaire was applied to 486 dentists living at five geographical regions of Brazil. The dentists answered a questionnaire containing four questions, in which they reported the most widely used restorative material for direct (amalgam, composite resin, and glass ionomer) and indirect restorations (gold, silver, and copper/aluminum alloys, indirect resin composites, and ceramics) and specified the reason for using the material type selected. Results: In 2004, amalgam was the direct restorative material most used by dentists at almost all regions, except from South region, where resin composite was the most used. Esthetics was the main reason stated for the use of resin composites. As for indirect restorations, metallic restorations were the most used in Northeast (77.8%). No differences were found regarding the material type use between metallic and aesthetic materials at North, Southeast and Center-West regions. At South region, esthetic restorations were the most used. Conclusion: Despite the limitations of this present study, direct and indirect metallic restorations were the most common materials in 2004.

Influence of Volume and Activation Mode on Polymerization Shrinkage Forces of Resin Cements

The concern with the polymerization shrinkage of restorative resin composites also applies to resin cements. The aim of this study was to evaluate the influence of volume and polymerization mode on forces generated during polymerization shrinkage (FGPS) of resin cements. Two light-cured resin cements - Variolink II (VL; Ivoclar Vivadent) and Nexus 3 (NX; Kerr) - and two self-cured resin cements - Multilink (ML; Ivoclar Vivadent) and Cement Post (CP; Angelus) - were inserted between two rectangular steel bases (6x2 mm) with distance set at 0.1, 0.3 and 0.5 mm, establishing a variation of volume. These steel bases were attached to a universal test machine with 50 kg load cell and forces (N) were registered for 10 min. Values of maximum forces generated by each material were subjected to two-way ANOVA and Tukey's test for individual comparisons (α=0.05). VL, NX and CP developed increasing FGPS as the volume of material increased, while ML presented the opposite behavior. It may be concluded that higher volume increases FGPS even with a concomitant decrease of C-factor, unless the resin cements present lower force generation rates as a function of time in combination with a low C-factor, resulting in stress relief and consequently lower values of FGPS.

Preocupação com a contração de polimerização de resinas compostas restauradoras também tem sido associada aos cimentos resinosos. O objetivo deste artigo foi avaliar a influência do volume e do modo de polimerização sobre as forças geradas durante a contração de polimerização (FGPS) de cimentos resinosos. Dois cimentos de ativação dual: Variolink II (VL - Ivoclar Vivadent) e Nexus 3 (NX - Kerr) e dois de ativação química: Multilink (ML - Ivoclar Vivadent) e Cement Post (CP - Angelus) foram inseridos entre as duas bases de aço retangulares (6x2 mm) com a distância ajustada em 0,1, 0,3 e 0,5 mm, estabelecendo uma variação no volume. Estas bases de aço foram fixadas a uma máquina de teste universal (Emic DL 500, com célula de carga de 50 kg) e as forças (N) foram registradas por 10 min. Os valores máximos de tensões geradas por cada material foram submetidas à ANOVA a dois critérios, seguido do teste de Tukey (p<0,05) para comparações individuais. VL, NX e CP desenvolveram maiores FGPS quando o volume de material aumentou, enquanto ML apresentou o comportamento inverso. Maiores volumes aumentam as FGPS mesmo com redução concomitante do Fator-C, a menos que o cimento resinoso apresente uma baixa taxa de geração de força em função do tempo associado a um baixo Fator-C, o que resulta em alívio das tensões e consequentemente menores valores de FGPS.

The influence of "C-factor" and light activation technique on polymerization contraction forces of resin composite

OBJECTIVES: This study evaluated the influence of the cavity configuration factor ("C-Factor") and light activation technique on polymerization contraction forces of a Bis-GMA-based composite resin (Charisma, Heraeus Kulzer). MATERIAL AND METHODS: Three different pairs of steel moving bases were connected to a universal testing machine (emic DL 500): groups A and B - 2x2 mm (CF=0.33), groups C and D - 3x2 mm (CF=0.66), groups e and F - 6x2 mm (CF=1.5). After adjustment of the height between the pair of bases so that the resin had a volume of 12 mm³ in all groups, the material was inserted and polymerized by two different methods: pulse delay (100 mW/cm² for 5 s, 40 s interval, 600 mW/cm² for 20 s) and continuous pulse (600 mW/cm² for 20 s). Each configuration was light cured with both techniques. Tensions generated during polymerization were recorded by 120 s. The values were expressed in curves (Force(N) x Time(s)) and averages compared by statistical analysis (ANOVA and Tukey's test, p<0.05). RESULTS: For the 2x2 and 3x2 bases, with a reduced C-Factor, significant differences were found between the light curing methods. For 6x2 base, with high C-Factor, the light curing method did not influence the contraction forces of the composite resin. CONCLUSIONS: Pulse delay technique can determine less stress on tooth/restoration interface of adhesive restorations only when a reduced C-Factor is present.

Impact of filler size and distribution on roughness and wear of composite resin after simulated toothbrushing

OBJECTIVES: Nanofilled composite resins are claimed to provide superior mechanical properties compared with microhybrid resins. Thus, the aim of this study was to compare nanofilled with microhybrid composite resins. The null hypothesis was that the size and the distribution of fillers do not influence the mechanical properties of surface roughness and wear after simulated toothbrushing test. MATERIAL AND METHODS: Ten rectangular specimens (15 mm x 5 mm x 4 mm) of Filtek Z250 (FZ2), Admira (A), TPH3 (T),Esthet-X (EX), Estelite Sigma (ES), Concept Advanced (C), Grandio (G) and Filtek Z350 (F) were prepared according to manufacturer's instructions. Half of each top surface was protected with nail polish as control surface (not brushed) while the other half was assessed with five random readings using a roughness tester (Ra). Following, the specimens were abraded by simulated toothbrushing with soft toothbrushes and slurry comprised of 2:1 water and dentifrice (w/w). 100,000 strokes were performed and the brushed surfaces were reanalyzed. Nail polish layers were removed from the specimens so that the roughness (Ra) and the wear could be assessed with three random readings (µm). Data were analyzed by ANOVA and Tukey's multiple-comparison test (α=0.05). RESULTS: Overall outcomes indicated that composite resins showed a significant increase in roughness after simulated toothbrushing, except for Grandio, which presented a smoother surface. Generally, wear ofnanofilled resins was significantly lower compared with microhybrid resins. CONCLUSIONS: As restorative materials suffer alterations under mechanical challenges, such as toothbrushing, the use of nanofilled materials seem to be more resistant than microhybrid composite resins, being less prone to be rougher and worn.

Comparative clinical study of the effectiveness of different dental bleaching methods - two year follow-up

This study evaluated color change, stability, and tooth sensitivity in patients submitted to different bleaching techniques. MATERIAL AND METHODS: In this study, 48 patients were divided into five groups. A half-mouth design was conducted to compare two in-office bleaching techniques (with and without light activation): G1: 35% hydrogen peroxide (HP) (Lase Peroxide - DMC Equipments, São Carlos, SP, Brazil) + hybrid light (HL) (LED/Diode Laser, Whitening Lase II DMC Equipments, São Carlos, SP, Brazil); G2: 35% HP; G3: 38% HP (X-traBoost - Ultradent, South Jordan UT, USA) + HL; G4: 38% HP; and G5: 15% carbamide peroxide (CP) (Opalescence PF - Ultradent, South Jordan UT, USA). For G1 and G3, HP was applied on the enamel surface for 3 consecutive applications activated by HL. Each application included 3x3' HL activations with 1' between each interval; for G2 and G4, HP was applied 3x15' with 15' between intervals; and for G5, 15% CP was applied for 120'/10 days at home. A spectrophotometer was used to measure color change before the treatment and after 24 h, 1 week, 1, 6, 12, 18 and 24 months. A VAS questionnaire was used to evaluate tooth sensitivity before the treatment, immediately following treatment, 24 h after and finally 1 week after. RESULTS: Statistical analysis did not reveal any significant differences between in-office bleaching with or without HL activation related to effectiveness; nevertheless the time required was less with HL. Statistical differences were observed between the results after 24 h, 1 week and 1, 6, 12, 18 and 24 months (intergroup). Immediately, in-office bleaching increased tooth sensitivity. The groups activated with HL required less application time with gel. CONCLUSION: All techniques and bleaching agents used were effective and demonstrated similar behaviors.