Avaliação in vitro de novos produtos na diminuição da permeabilidade dentinária antes e após desafios ácidos / In vitro evaluation of new products in regarding dentin permeability reduction before and after acid challenge model

Objetivo: avaliar in vitro a efetividade de aplicações sucessivas de diferentes produtos utilizados para o tratamento da hipersensibilidade dentinária cervical na redução da permeabilidade dentinária, assim como avaliar a resistência destes produtos a desafios ácidos. Material e métodos: foram utilizados 72 terceiros molares humanos íntegros para a preparação de 72 amostras, que foram ligadas a um sistema de pressão hidráulica para mensurar a permeabilidade dentinária após os seguintes passos: 1) preparação da amostra; 2) tratamento com ácido fosfórico a 37% durante 30 segundos; 3) cinco aplicações dos produtos testados; 4) primeiro desafio ácido; 5) segundo desafio ácido; e 6) terceiro desafio ácido. As amostras foram divididas aleatoriamente em seis grupos (n=12), de acordo com os tratamentos propostos: Desensibilize Nano P, Clinpro XT, dentifrício Colgate Sensitive Pró-Alívio, dentifrício Duraphat, dentifrício Sensodyne Repair e após restauração com resina composta (grupo-controle). Conclusão: que todos os produtos testados foram capazes de promover a redução da permeabilidade dentinária significativamente, sendo que os grupos Clinpro XT, Desensibilize Nano P e controle mantiveram esses níveis reduzidos estatisticamente até o terceiro desafio ácido, enquanto que os dentifrícios Duraphat, Sensodyne Repair e Colgate Sensitive Pró-Alívio mantiveram essas reduções estatisticamente significativas até o segundo desafio ácido.

Objective: to evaluate in vitro the effectiveness of successive applications of different products used for the treatment of cervical dentinal hypersensitivity, reducing dentin permeability, as well as to evaluate the resistance of these products, acids challenges. Material and methods: 72 intact human third molars were used for the preparation of 72 samples were bound to a hydraulic pressure system to measure the dentin after the following steps: 1) sample preparation; 2) treatment with 37% phosphoric acid for 30 seconds; 3) 5 applications of the products tested; 4) first challenge acid; 5) second challenge acid; 6) third challenge acid. The samples were randomly divided into 6 groups (n=12) according to the proposed treatments: Desensibilize Nano P, Clinpro XT, toothpaste Colgate Sensitive Pro-Relief, Duraphat toothpaste, toothpaste Sensodyne Repair and after restoration with composite resin (control group). Conclusion: all products tested were able to significantly promote the reduction of dentin, and the Clinpro XT groups Desensibilize Nano P and control these reduced levels remained statistically to the third challenge acid, while toothpaste Duraphat, Sensodyne Repair and Colgate Sensitive Pro-Relief kept these statistically significant reductions to the second challenge acid.

Role of topical drugs in treatment of oral mucosal diseases. A literature review.

Few topical formulations have been designed specifically to treat oral mucosal diseases. Local drug delivery may provide a more targeted and efficient option than systemic delivery for diseases of the oral mucosa. The permeability to the topical drugs differs according to the thickness of the epithelium and the extent of keratinization. The loss of the permeability barrier in the oral mucosa, due to ulceration or erosion, leads to rapid diffusion of the drug into tissues as compared to the intact areas of the mucosa. Oral mucosal delivery has the potential to treat many different conditions and diseases, such as oral cancer, mucositis, lichen planus, herpes simplex, candidiasis, recurrent aphthous stomatitis, vesiculo-bullous diseases, neuropathic pain and salivary dysfunction. Each therapy requires distinct penetration and drug retention profiles in order to optimize treatment and minimize side effects. In this paper, topical medications are discussed, as these are advantageous for the treatment of oral mucosal lesions with fewer side effects.

Oral local drug delivery and new perspectives in oral drug formulation.

Modern pharmaceutical science has provided us with a wide range of substances to be administered with a wide large variety of dosage forms. Local drug delivery systems have been used for a long time; in particular, for the local therapy of diseases affecting the oral cavity. Although these diseases are often extremely responsive to local therapy, the mouth often presents various difficulties in the application of topical compounds (owing to saliva and the mouth's different functions), resulting in a short retention time of dosage forms with a consequent low therapeutic efficacy. To resolve these limitations, research today concentrates on the development of bioadhesive formulations. This review focuses on the permeability features of oral mucosa, the rationale of oral local drug delivery, and new potential bioadhesive local delivery systems. Furthermore, the most promising mucoadhesive systems proposed to locally treat oral diseases are discussed.

Efeito de um sistema de liberação controlada de cloredixidina para o controle de placa e gengivite / Effect of chlorhexidine in a controlled release system for plaque control and gingivitis

Pacientes submetidos a tratamento com aparelhos fixos estão sujeitos a apresentar alterações periodontais significativas. Os acessórios ortodônticos adaptados às coroas dentárias dificultam a manutenção da higiene bucal ao criando um aumento significativo de superfícies retentivas, favorecendo o acúmulo do biofilme bacteriano. Caracterizando um desequilíbrio na microflora local contribuindo para o desenvolvimento de alterações periodontais. O objetivo deste estudo foi comparar a efetividade de um novo sistema de liberação controlada de clorexidina na formulação 0,6% e tratamento profilático no controle da placa e gengivite em pacientes ortodônticos. Este estudo foi constituído de 29 indivíduos provenientes de clínicas do Curso de Especialização em Ortodontia da Faculdade de Odontologia da Universidade Federal de Minas Gerais com diagnóstico de gengivite...

Influência de fármacos na movimentação dentária induzida / The influence of drugs on orthodontic tooth movement

A Ortodontia está fundamentada na habilidade do profissional em produzir umacontrolada movimentação dos dentes através do osso alveolar, a partir da aplicação da forçaortodôntica. Entretanto, a movimentação ortodôntica pode ser influenciada por vários fatores,dentre eles, o uso de medicamentos. Em vista do exposto, o objetivo deste trabalho foirealizar uma revisão narrativa da literatura sobre a influência de fármacos ou suplementos namovimentação dentária induzida. Como a maior parte dos trabalhos foi realizada com animaise não com humanos e há grande variabilidade entre as metodologias, não se pode afirmarcategoricamente sobre qualquer modificação na movimentação ortodôntica causada poralgum tipo de fármaco que o paciente utilize durante o tratamento ortodôntico. Vislumbra-se,futuramente, atuar na taxa da movimentação ortodôntica com o auxílio de medicamentos.

Orthodontics is based on the professional's ability to produce a controlledteeth movement in alveolar bone through the application of orthodontic force. However, theorthodontic movement may be influenced by several factors, including the use of medicines.Due to it, the aim of this study was to perform a narra tive literature review on the effectsof drugs on experimental tooth movement. As most experimental studies were done withanimais instead of humans and there is a great variability among the methodologies, stetementscannot yet be done about any change in tooth movement caused by some kind ofmedication took by patients during orthodontic treatment. We envision in the future actingon orthodontic tooth movement with the aid of drugs.

Effect of Nd:YAG laser and acidulated phosphate fluoride on bovine and human enamel submitted to erosion/abrasion or erosion only: an in vitro preliminary study.

OBJECTIVE: The aim of the present in vitro study was to evaluate, using two different methodologies, the effectiveness of pulsed Nd:YAG laser irradiation associated with topical acidulated phosphate fluoride (APF) for preventing enamel erosion and structure loss under regimes of erosion and abrasion or erosion only. BACKGROUND DATA: An increased incidence of noncarious lesions (erosion and abrasion) has been observed, consequently new preventative therapies have been proposed. MATERIALS AND METHODS: Two different methodologies were performed. For the first, 100 bovine crowns were submitted to four different treatments (n = 25): no treatment (control), 4 min application of APF, Nd:YAG laser irradiation (1 W, 100 mJ, 10 Hz, 141.5 J/cm(2)), and Nd:YAG laser irradiation + 4 min of APF. After the specimens were exposed to citric acid (2% w/v; 30 min), they were submitted to 5000 brushing cycles. Specimen mass was measured before and after the treatments. For the second methodology, 20 human crowns were embedded in acrylic resin and cut surfaces were exposed and polished. The specimens were divided into four groups (n = 10): no treatment (control), APF for 4 min, Nd:YAG laser irradiation (1 W, 100 mJ, 10 Hz, 125 J/cm(2)), and Nd:YAG laser irradiation + APF. The samples were then immersed in citric acid (2% w/v; 90 min). Vickers hardness was obtained before and after the treatments. RESULTS: The Nd:YAG laser irradiation + APF (bovine and human enamel) was more effective and yielded statistically significant results for surface microhardness and enamel wear. CONCLUSION: Nd:YAG laser irradiation associated with APF reduced bovine enamel wear and human enamel softening when samples were submitted to a regime of erosion and abrasion or erosion only in vitro.

Antimicrobial activity and local release characteristics of chlorhexidine diacetate loaded within the dental copolymer matrix, ethylene vinyl acetate.

In vitro results are presented for a novel oral drug-delivery system ultimately intended for treatment of oral infections in immunocompromised patients. Test samples of ethylene vinyl acetate copolymer (EVA) containing chlorhexidine diacetate (CDA) showed desirable antimicrobial properties and steady, slow release into aqueous and other media after an initial burst of drug release in the first day of liquid exposure. By washing away this initial burst, the proposed mouthguard device should be capable of sustained delivery of locally effective CDA concentrations far below systemically toxic levels. A prolonged room temperature shelf-life of at least 1 year, and effectivity against a wide range of oral bacteria and Candida species was demonstrated. Drug loaded films showed a top-to-bottom asymmetry in drug release, but good lateral homogeneity, and a linear relationship between initial CDA loading concentration (from 0.63 to 10 wt %) and days 3-14 release rates in a static aqueous environment. The EVA matrix containing CDA appears to possess many suitable properties for localized oral delivery of sustained antimicrobial activity.

Poly(ethylene-co-vinyl acetate) copolymer matrix for delivery of chlorhexidine and acyclovir drugs for use in the oral environment: effect of drug combination, copolymer composition and coating on the drug release rate.

OBJECTIVES: This study utilizes a bio-compatible ethylene vinyl acetate (EVA) copolymer to deliver drugs at therapeutic levels over extended periods of time. The release rate of an anti-fungal and an anti-microbial drug namely acyclovir (ACY) and chlorhexidine diacetate (CDA) from EVA was investigated individually and as a mixture. The effect of drug combination, the composition of the copolymer and the coating of the matrix with a different polymer on the rate of drug release are presented. METHOD: Polymer casting solutions were prepared by homogeneously dissolving EVA copolymer and the drugs in the ratio (40:1) in dichloromethane. The drugs ACY and CDA were used individually as well as in three different weight ratios maintaining the total drug concentration in the polymer at 2.5%. Different concentrations of vinyl acetate (VA) 28, 32 and 40% in the EVA matrix were used to study the release of either ACY or CDA alone while 40% VA was used for the release study of the individual drug as well as their mixtures. Thin square films of 3cmx3cm with a thickness of 0.7mm were cut from the dry sheet obtained by solvent evaporation. Coated films were prepared by dipping ACY and CDA drug-loaded EVA films (VA 40%) into EVA copolymer of VA 32% and then dried. All of the drug-loaded samples were extracted at 37 degrees C in 10ml distilled water that was replaced daily. The rate of individual drug release was measured by UV-spectrophotometer while the mixtures of drugs were measured by high performance liquid chromatography (HPLC). RESULTS: The release rate of ACY is higher than that of CDA both individually and in the ACY/CDA 50/50 mixture. In the other mixtures, the release of the drug is proportional to its concentration in the mixture. Total release of ACY is higher than CDA in most compositions. The effect of increasing the vinyl acetate content of the EVA matrix increased the drug release rate (p=0.02) while coating of films resulted in a decrease of the release rate of the drugs. SIGNIFICANCE: Measurements of the in vitro rate of drug release showed that there was a sustained release of drug at an almost constant concentration over extended period of time, thus providing a basis for oral treatment modality. We show that it is possible to alter the rate of drug release in the EVA matrix to a desired value by: (1) changing the composition of the EVA copolymer, (2) altering the mixtures of drugs and (3) coating the matrix with additional polymer. The use of mixtures of drugs that can enhance or decrease the rate of drug release may prove more effective in treating persistent oral infections in immunocompromised patients.