Color stability of a nanofill composite: effect of different immersion media

OBJECTIVE: The aim of this in vitro study was to evaluate the color stability of a nanofill composite resin (Filtek Z350) in different immersion media. MATERIALS AND METHODS: Twelve resin-based composite specimens were prepared using a silicon cylindrical mold measuring ≅1mm of thickness and ≅ 10mm of diameter. Specimens were light-cured for 40 s from both sides using a LED Radii at 1400 mW/cm² and were randomized into 4 groups (n= 3) according to immersion media: coffee, yerba mate, grape juice or water (control solution). A digital spectrophotometer was used to evaluate the color changes at baseline and at 1-week after immersion in each solution. Specimens were stored in the different staining media for 4 h/day during 1 week. The color differences (DE) were analyzed by paired t-test and one-way ANOVA with complementary Tukey test (p;0.05) CONCLUSIONS: The findings of the present study suggest that the tested nanofill resin-based composite was susceptible to staining by substances present in the grape juice

Tetrahydrofuran as solvent in dental adhesive systems

O objetivo deste estudo será avaliar o desempenho do tetrahidrofurano (THF) como solvente na composição do primer de um adesivo odontológico experimental através da resistência de união à microtração em dentina após 24h e 6 meses de armazenamento em água. Sessenta incisivos bovinos serão distribuídos aleatoriamente em dez grupos, conforme o tipo de solvente: 1) THF, 2) acetona, 3) etanol, 4) água, 5) THF/água, 6) acetona/água, 7) etanol/água, 8) All Bond 2 (acetona/etanol/água), 9) Opti Bond FL (etanol/água) e 10) Scotch Bond (água). O desgaste na face vestibular dos dentes será realizado até exposição da dentina superficial com lixas de carbeto de silício sob refrigeração. Depois que a superfície dentinária for condicionada com gel de ácido fosfórico a 35% (15s) e lavada com água (30s), o excesso de água superficial será removido com papel absorvente. Nos grupos experimentais, o primer será aplicado sob agitação constante (30s) seguido de jato de ar por (10s) a distância de 10cm, a fim de auxiliar a evaporação do solvente. Uma camada de resina adesiva experimental será aplicada e fotoativada (20s). Os sistemas adesivos de marcas comerciais serão aplicados conforme instruções dos fabricantes. As restaurações serão realizadas com compósito restaurador pela técnica incremental. Os incrementos serão fotoativados individualmente a 1400mW/cm2. Após o período de 24 horas de armazenamento em água a 37ºC, as amostras serão seccionadas obtendo-se uma área de secção transversal de aproximadamente 0,5mm2. Metade dos corpos de prova será testada imediatamente e a outra metade será mantida sob as mesmas condições de armazenamento para avaliação após 6 meses.A resistência de união à microtração (MPa) será testada através de uma máquina universal de ensaios mecânicos (1,0mm/min/100N). As porções correspondentes à dentina serão analisadas por microscopia de luz (500X) e classificadas de acordo com o padrão de fratura em: CD) falhas coesivas em dentina, CC) falhas coesivas em compósito restaurador, A) falhas adesivas, M) falhas mistas ou FP) falhas prematuras. Significância estatística será considerada quando α=0.05The aim of this study is to evaluate the performance of tetrahydrofuran (THF) as solvent in the primer composition of an experimental adhesive system on the resin-dentin microtensile bond strength after 24h and 6 months of water storage. Sixty bovine incisors will be randomly separated into ten groups, according to the solvent type: 1) THF, 2) acetone, 3) ethanol, 4) water, 5) THF/water, 6)acetone/water, 7) ethanol/water, 8) All Bond 2 (acetone/ethanol/water), 9) Opti Bond FL (ethanol/water) e 10) Scotch Bond (water). Vestibular enamel will be removed to, expose the superficial dentin and further polished with grit silicon-carbide under irrigation. After acid etching with 35% phosphoric acid (15s), the surfaces will be rinsed with water (30s) and the excess of superficial water will be removed with absorbent paper. Each experimental primer will be applied with agitation (30s) followed by a gently air stream (10s) at a distance of 10cm to help solvent evaporation. One coat of an experimental adhesive resin will be applied and lightactivated (20s). The marketed available adhesive systems will be used according manufacturer instructions. Resin composite restorations will be constructed incrementally. Each layer of composite will be light-activated individually at 1400mW/cm2. After water storage for 24h at 37oC, the restored teeth will be sectioned to obtain sticks with a cross-sectional area of approximately 0.5mm2. Half of specimens will be tested after 24 hours and the other half will be maintained in the same storage conditions to be evaluated after 6 months. Microtensile bond strength (MPa) will be evaluated with an universal testing machine (1.0mm/min/100N). The half corresponding to dentin will be evaluated in a light microscope (500X) and classified as: CD) cohesive in dentin, CC) cohesive in resin composite, A) adhesive, M) mixed or PD) premature debonded. Statistical significance will be set at α=0.0

Clinical evaluation of the effects of two techniques isolation of the operative field on the performance of Class V restorations and periodontal condition

During restorative procedures, different isolation methods of the operative field can be used to promote moisture control and retraction of the gingival tissues. The aim of the present clinical trial was to evaluate the effects of two isolation techniques on the clinical performance of Class V restorations, as well on the periodontal conditions of restored sites. Patients presenting at least two noncarious cervical lesions (NCLs) were enrolled in this study. The NCLs were randomized into the following groups: (1) isolation performed with rubber dam and gingival retraction clamp and (2) isolation provided with cotton rolls and gingival retraction cord. Both techniques were used with a saliva suction device. All restorative procedures were performed using a selfetching adhesive system and a nanofilled composite resin according to the manufacturer s instructions. The clinical performance of restorations was recorded in terms of fracture and retention of restoration, marginal adaptation, marginal staining, postoperative hypersensitivity, and preservation of tooth vitality at 1 week and 6 months after placement.The periodontal condition of restored sites was evaluated based on the presence of supragingival plaque, gingival marginal bleeding, probing depth, and relative gingival recession. Thirty patients were enrolled in the study, yielding a total of 136 restorations (68 restorations per group). At the 6-month followup, one restoration from the rubber dam group and three restorations from the cotton roll group lost retention. In this period, the highest incidence of small marginal defects was observed in the group isolated with cotton rolls (p= 0.01). Both groups showed a statistically significant increase in supragingival plaque at six months after restoration placement (p 0.05). Within the limits of this study, it can be concluded that both isolation techniques resulted in equally clinically acceptable restorations without producing negative effects on periodontal tissuesDurante os procedimentos restauradores, diferentes métodos de isolamento do campo operatório podem ser utilizados a fim de promover controle de umidade e retração de tecidos gengivais. O objetivo do presente ensaio clinico foi avaliar os efeitos de duas técnicas de isolamento no desempenho clínico de restaurações Classe V, bem como na condição periodontal dos sítios restaurados. Pacientes apresentando, no mínimo, duas lesões cervicais não cariosas (LCNCs) foram selecionados para este estudo. As LCNCs foram randomizadas nos seguintes grupos: (1) isolamento com lençol de borracha e grampo retrator de gengiva e (2) isolamento com rolos de algodão e fio retrator de gengiva. Um sugador de saliva foi utilizado em ambas as técnicas. Todos os procedimentos restauradores foram executados com sistema adesivo autocondicionante e compósito restaurador nanoparticulado, seguindo as instruções dos fabricantes. O desempenho clinico das restaurações foi avaliado em termos de fratura e retenção da restauração, adaptação marginal, manchamento marginal, sensibilidade pós-operatória e preservação da vitalidade pulpar após 1 semana e 6 meses da inserção das restaurações.A condição periodontal dos sítios restaurados foi avaliada com base na presença de placa supragengival, sangramento gengival marginal, profundidade de sondagem e recessão gengival relativa. Trinta pacientes foram incluídos no estudo, resultando num total de 136 restaurações (68 restaurações por grupo). Após seis meses de acompanhamento, uma restauração do grupo isolado com lençol de borracha e três restaurações do grupo isolado com rolos de algodão perderam a retenção. Neste período, uma maior incidência de pequenos defeitos marginais foi observada no grupo que recebeu isolamento com rolos de algodão (p= 0.01). Ambos os grupos apresentaram um aumento significativo do acúmulo de placa supragengival após 6 meses da inserção das restaurações (p< 0.05). Porém, não foram detectadas diferenças estatisticamente significativas entre os dois grupos testados considerando os critérios utilizados para avaliação das restaurações e da condição periodontal (p> 0.05). Dentro das limitações deste estudo, foi possível concluir que ambas as técnicas de isolamento resultaram em restaurações clinicamente aceitáveis, sem produzir efeitos negativos nos tecidos periodontai

RESTAURACIÓN SEMIDIRECTA DE RESINA COMPUESTA: UNA ALTERNATIVA PARA DIENTES POSTERIORES - REPORTE DE CASO CLÍNICO

Las restauraciones semidirectas de resina compuesta para el tratamiento de dientes posteriores conextensa p&eacute;rdida de tejido dentario surgieron hace algunos a&ntilde;os como una alternativa de tratamientofrente a las restauraciones directas en resina, amalgama y restauraciones cer&aacute;micas. Utilizando unat&eacute;cnica que permita la confecci&oacute;n extraoral de la restauraci&oacute;n, es posible optimizar las condicionescl&iacute;nicas de trabajo y mejorar las propiedades finales del material restaurador. El presente trabajo tienepor objetivo reportar un caso cl&iacute;nico donde se utiliz&oacute; una restauraci&oacute;n semidirecta de resina compuestapara substituir una restauraci&oacute;n defectuosa de amalgama. En este trabajo se describen losprocedimientos cl&iacute;nicos realizados y se discuten las ventajas y desventajas asociadas a la t&eacute;cnicautilizada.ABSTRACT Semi-direct composite restorations to treat teeth with large tooth loss appeared recently as an alternativeto the direct restorations (amalgam and composite) and the ceramic restorations. Using an extraoraltechnique to produce the restoration will improve the clinical conditions and the mechanical properties.Here, we reported a case where a semi-direct composite restorations was employed to replace adefective large amalgam restoration. The report describes the clinical procedures and discuss theadvantages and disadvantages associated to the technique

Effectiveness of different carbamide peroxide concentrations used for tooth bleaching: an in vitro study

OBJECTIVES: This in vitro study evaluated the effectiveness of three carbamide peroxide concentrations used for tooth bleaching treatments. MATERIAL AND METHODS: Sixty bovine dental slabs (6x6x3 mm) were obtained, sequentially polished, submitted to artificial staining (baseline) and randomized into four groups (n=15), according to the bleaching agent concentration: distilled water (control), 10% (CP10), 16% (CP16) or 37% (CP37) carbamide peroxide. CP10 and CP16 were covered with 0.2 mL of the respective bleaching gels, which were applied on enamel surface for 4 h/day during two weeks. Samples of CP37 were covered with 0.2 mL of the bleaching gel for 20 min. The gel was light activated by two 40-s applications spaced by 10-min intervals. The gel was renewed and applied 3 times per clinical session. This cycle was repeated at 3 sessions with 5 days of interval between them. Tooth shade evaluations were done with a digital spectrophotometer at T0 (baseline), T1 (after 1-week of treatment) and T2 (1-week post-bleaching). Tooth shade means were statistically analyzed by Kruskal-Wallis and Friedman's tests and color parameters were analyzed by two-way ANOVA and Tukey's test (p<0.05). RESULTS: At T1 and T2 evaluations, tooth shade was significantly lighter than at baseline for all treatment groups, considering the color parameters &#916;L*, &#916;a*, &#916;b*, &#916;E* (p<0.001) or tooth shade means (p<0.001). CP37 group showed lower shade mean change than CP10 and CP16 at T1 (p<0.01), but this difference was not statistically significant at T2 (p&gt;0.05). CONCLUSIONS: One week after the end of the treatment, all carbamide peroxide concentrations tested produced similar tooth color improvement

The effect of investment materials on the color of feldspathic ceramics

Objectives: The aim of this study was to evaluate the influence of investment type on the color of feldspathic ceramics. Methods: Ceramic specimens were constructed using the refractory die technique, using four investments (i.e., Vitadurvest, Duravest, Duceralay Superfit, and Fortune) to observe their effect on the color of five commercially available ceramics (i.e., Super Porcelain EX-3, Vision Esthetic, Vintage Halo, IPS Classic, and Vitadur Alpha). The color analysis of the ceramics was performed with a colorimeter using the CIE L*a*b* color coordinates. Results: The investments produced significant alterations on a*, b*, and L* color parameters of the ceramics tested. The ceramic Vision Esthetic was influenced by the type of investment in all color parameters (P<.05). Two investments (Duravest and Fortune) produced alterations in color parameters with three of the five ceramics tested. Conclusions: The investment materials produced alterations on the ceramic color parameters, resulting in unacceptable chromatic alterations (ΔE*). (Eur J Dent 2011;5:433-440

A survey of oral and maxillofacial biopsies in children: a single-center retrospective study of 20 years in Pelotas-Brazil

Despite the large number of published cases about oral and maxillofacial pediatric lesions, the literature is scarce on epidemiological studies regarding the prevalence of these entities. This study retrieved oral and maxillofacial pediatric lesions from the Center of Diagnosis of Oral Diseases (CDDB) at the Dental School of the Federal University of Pelotas (UFPEL), comprising a 20-year period (1983-2002). From the total of 9,465 biopsies received in this period, 625 (6.6%) were from children aged 0 to 14 years. Regardless of the histopathological diagnosis, patient data referring to lesion location, sex and age were collected. Diagnoses were grouped in 13 categories. As much as 89% of the cases occurred in patients aged 7 to 14 years (53% in females and 47% in males). Mucocele (17.2%) was the most common type of lesion, followed by dentigerous cyst (8.6%). In the category of odontogenic tumors, odontoma was the most frequent lesion (64.2%). Malignant lesions were observed in a small section of the sample (1.2%). Generally, the results of the present study are in line with those reported in the literature concerning the most prevalent lesions in the pediatric population. Most lesions were benign, and malignant lesions were diagnosed in a very small part of the sample

Modeling Public Policies in Latin America and the Caribbean

This book contains a selection of studies discussed at the first and second Regional Meetings on Computable General Equilibrium, which were held, respectively, in Santiago, Chile on 13 and 14 April 2007 with the collaboration of the Centre for International Prospective Studies and Information (CEPII), and San Jose, Costa Rica, from 24 to 25 November 2008, with the collaboration of the Central American Institute of Business Administration (INCAE). They deal with issues such as trade policy, regional integration, trade in services, fiscal policy, the impact of food price surges and climate change; are based on comparable methodologies; and shed light on the implications of crucial policy alternatives that Latin American regional policymakers are currently facing. With this publication, ECLAC and IDB hope to disseminate the studies broadly among policymakers and to encourage new generations of modelers to further analytical work in this area.