Digital guided veneer preparation: A dental technique.

This article describes a digital workflow for ceramic veneer preparation using computer-aided design and computer-aided manufacturing technology. A digital waxing was planned on the exocad software program to reestablish esthetic and functional parameters. Then, the digital guides for veneer preparation were designed by using the Meshmixer design software program to control the tooth structure removed during preparation to the minimal thickness necessary for the definitive restorations. The digital guides were printed in an additively manufactured clear resin and used in the preparation appointment, allowing a more conservative and controlled preparation.

Digital Impressions in Implant Dentistry: A Literature Review.

INTRODUCTION: Digital impressions in implant dentistry rely on many variables, and their accuracy, particularly in complete edentulous patients, is not well understood. Aim. The purpose of this literature review was to determine which factors may influence the accuracy of digital impressions in implant dentistry. Emphasized attention was given to the design of the intra-oral scan body (ISB) and scanning techniques. MATERIALS AND METHODS: A Medline, PubMed and EBSCO Host databases search, complemented by a hand search, was performed in order to select relevant reports regarding the appliance of digital impressions in implant dentistry. The search subject included but was not limited to accuracy of digital impressions in implant dentistry, digital scanning techniques, the design and material of the ISBs, and the depth and angulation of the implant. The related titles and abstracts were screened, and the remaining articles that fulfilled the inclusion criteria were selected for full-text readings. RESULTS: The literature search conducted for this review initially resulted in 108 articles, among which only 21 articles fulfilled the criteria for inclusion. Studies were evaluated according to five subjects: accuracy of digital impressions in implant dentistry; the design and material of the intra-oral scan bodies; scanning technique; the influence of implants depth/angulations on the digital impression and accuracy of different intra-oral scanner devices. CONCLUSIONS: The accuracy of digital impressions in implant dentistry depends on several aspects. The depth/angulation of the implant, the experience of the operator, the intra-oral scanner used, and environmental conditions may influence the accuracy of digital impressions in implant dentistry. However, it seems that ISBs' design and material, as well as scanning technique, have a major impact on the trueness and precision of digital impressions in implant dentistry. Future research is suggested for the better understanding of this subject, focusing on the optimization of the ISB design and scanning protocols.

Formation of biofilms by Staphylococcus aureus on stainless steel and glass surfaces and its resistance to some selected chemical sanitizers

The objectives of this work were to verify the capability of Staphylococcus aureus of forming bio-film on stainless steel and glass surfaces; to evaluate the efficiency of sodium dichloroisocyanurate, hydrogen peroxide and peracetic acid in inactivating Staphylococcus aureus cells adhered onto these surfaces; and to visualize biofilm development by scanning electron microscopy before and after sanitizer treatment. The surfaces studied consisted of 10x20mm chips immersed in Petri dishes containing BHI broth inoculated with S. aureus ATCC 25923. Biofilm formation was observed after 15-day incubation, when the cells were removed using the swab technique, followed by Baird Parker agar plating. Also, the efficiency of the chemical sanitizers on the chip surfaces was tested and the non-removed cells were counted on the Baird-Parker agar. After biofilm formation and use of sanitizers, the chips were respectively observed by scanning electronic microscopy following a pre-existing protocol. The obtained results showed biofilm formation on both surfaces, with bacterial count in the order of 10(7) CFU/cm² on and 10(8) CFU/cm² on stainless steel and glass surfaces, respectively. Peracetic acid was the most efficient in removing adhered cells, presenting 5.26 and 4.5 decimal reduction for adhered cells on stainless steel and glass surfaces, respectively.

Os objetivos deste trabalho foram verificar a capacidade de Staphylococcus aureus formar biofilme nas superfícies de aço inoxidável e vidro, avaliar a eficiência do dicloroisocianurato de sódio, peróxido de hidrogênio e ácido peracético na inativação de células de S. aureus aderidas e visualização por microscopia eletrônica de varredura, o desenvolvimento antes e depois do tratamento das superfícies com os sanificantes. As superfícies foram cupons 10x200mm imersos em placas de Petri contendo caldo BHI inoculado com cultura de Staphylococcus aureus ATCC 25923. A formação de biofilme foi observada após 15 dias de incubação, quando as células foram removidas pela técnica do suabe, seguiram-se diluições seriadas e plaqueamento em ágar Baird Parker. Testou-se a eficiência dos sanificantes nas superfícies dos cupons e as células não removidas foram enumeradas no ágar Baird Parker. Os cupons após formação do biofilme e cupons sanificados foram observados pela microscopia eletrônica de varredura seguindo um protocolo. Os resultados obtidos indicaram a formação de biofilme em ambas superfícies, com contagens bacterianas na ordem de 10(7) UFC/cm² e 10(8) UFC/cm² nas superfícies de aço inoxidável e vidro, respectivamente. Dentre os sanificantes estudados o ácido peracético apresentou uma eficiência maior na remoção das células aderidas, apresentado redução decimal de 5,26 e 4,5 para as células aderidas na superfície de vidro e aço inoxidável.

Avaliaçäo na precisäo da odontometria com o Justy II, localizador eletrônico de ápice / Evaluation of the precision in root canal length measuring with Justy II, electronic apex locator

Os autores apresentam uma avaliaçäo clínica do uso do aparelho eletrônico Justy II para determinaçäo da odontometria em 202 dentes tratados endodonticamente, perfazendo um total de 407 canais. O índice de acerto nas condutometrias com esse aparelho foi de 100 por cento

Efeito do cloreto de níquel sobre o desenvolvimento do germe dental de molares e do processo alveolar / Effect of nickel chloride on molar tooth germ and alveolar bone development

Camundongos fêmeas receberam injeção de 30 mg/kg de cloreto de níquel no 10° dia de gestação. Os animais foram sacrificados no 16° dia de gestação, ao nascimento e aos 3 dias de idade. As cabeças foram incluídas em parafina, de modo a fornecerem cortes frontais e corados para análise histológica. Os resultados mostraram, no 16° dia de gestação, semelhança nas estruturas morfológicas dos órgãos dentais dos animais controles e tratados e atraso na formação óssea do processo alveolar. Nos demais períodos de observação não houve diferenças observáveis tanto no desenvolvimento dos germes dentais quanto do processo alveolar entre os dois grupos de animais. Concluiu-se que o cloreto de níquel atrasa, reversivelmente, o desenvolvimento e a ossificação do processo alveolar, sem interferir no desenvolvimento dos germes dentais