Effect of light-curing units on gap formation and microleakage of class II composite restorations

Aim: This in vitro study evaluated gap width formation and marginal microleakage in Class IIcomposite restorations light-cured with three different light-curing units. Methods: Standardizedcavities in the proximal surfaces of 36 human third molars were made with margins located belowthe cementoenamel junction. Cavities were restored with Filtek P60 (3M ESPE), inserted with aphotocondenser tip and light-cured with three different methods: GI - Optilux401 (halogen); GII –ColtoluxLED (LED) and GIII –UltraLumeLED5 (LED). After finishing the restorations, teeth weresubjected to a thermal cycling regimen of 500 cycles (5oC ± 2oC and 55oC ± 2oC), totalizing 500cycles. Thereafter, the teeth were sectioned in a buccolingual direction and in the center of therestorations. Half of the specimens (18) were used to evaluate marginal microleakage, by measuringof dye penetration in cross-sectioned specimens, and the other half was used to analyzed the gapformation width by SEM observations (1000X). Data were submitted to Kruskal-Wallis (α=0.05).Results: The mean values of gap width (μm) were: GI 3.28±3.34; GII 1.48±1.89 and GIII3.11±3.45, and microleakage was not affected by the light-curing units. Conclusions: Therewere no differences between the light-curing methods in gap formation and marginal microleakage.

In vitro and in vivo analyses of the effects of desensitizing agents on dentin permeability and dentinal tubule occlusion.

This study was done to assess the influence of the topical application of two different desensitizing agents on dentin permeability and dentinal tubule occlusion. Twenty-one rats provided 84 teeth: 36 for the in vitro and 48 for the in vivo investigation. The following agents were tested: Group 1, 2% potassium nitrate plus 2% sodium fluoride gel; Group 2, 5% sodium fluoride varnish; Group 3, 3% hydroxyethylcellulose gel (control). Cervical cavities were prepared and EDTA was applied to expose the dentinal tubules. After each treatment, Evans blue dye was applied to the teeth. Dentin permeability, scanning electron microscope (SEM) sections, and energy dispersive X-ray (EDX) were analyzed. One-way ANOVA was used to compare the data. There were significant differences (P < 0.05) among groups for dentin permeability, number of tubules/mm(2), tubule area and tubular diameter. Groups 1 and 2 (both in vitro and in vivo) showed open and partially occluded tubules. Group 3 had the most open tubules. EDX revealed similar composition for both experimental conditions. Within the limits of the study, 2% nitrate potassium plus 2% sodium fluoride gel and 5% fluoride varnish decreased the dentin permeability, resulting in partial tubular occlusion.

Uso de inhibidores de metaloproteinasas en la terapia periodontal / Use of metaloproteinasas inhibitors in periodontal therapy

Las metaloproteinasas de la matriz (MMPs) son una familia de enzimas proteolíticas metalodependientes que promueven la degradación de los componentes de la matriz extracelular,siendo una de las principales responsables por la degradación de colágeno durante la destrucción de los tejidos periodontales. El desequilibrio entre la degradación y la producción de colágeno debido a los altos niveles de MMPs en los tejidos periodontales inflamados, promueve la pérdida de inserción periodontal. Las enzimas liberadas degradan el colágeno que forma la base estructuraldel periodonto, promoviendo así la destrucción tisular. La actividad de las MMPs en el substrato de la matriz extracelular es regulada por la transcripción y activación de las proenzimas inactivas, la interacción con componentes específicos de la matriz extracelular y principalmente por los inhibidores tisulares endógenos de metaloproteinasas (TIMPs). En la terapia periodontal han sido administradas dosis subantimicrobianas de doxiciclina como coadyuvante al raspaje y alisado radicular, debido a sus propiedades de inhibición en la actividad de las MMPs. En este estudio,fueron revisados aspectos importantes de las MMPs, discutiéndose el papel de los TIMPs y de los inhibidores sintéticos de metaloproteinasas, el uso de dosis subantimicrobianas de doxiciclina,así como de antiinflamatorios no esteroideos (AINES) en la terapia periodontal. Ya que las MMPs participan activamente del proceso destructivo de la enfermedad periodontal, es importante el uso de inhibidores sintéticos de estas enzimas en la terapia periodontal con la finalidad de minimizar la destrucción del periodonto.

Matrix metalloproteinases (MMPs) are a family of proteolytic enzymes that promote degradation of extracellular matrix components, one of the main responsible for the degradation of collagen during the destruction of periodontal tissues. A disturbed balance between degradation and production of collagen, due to high levels of MMPs in periodontal tissues, promotes periodontal attachment loss. Released enzymes degrade collagen that forms the structural basis of the periodontium, thereby promoting tissue destruction. The activity of MMPs in the substrate of the extracellular matrix is regulated by the transcription and activation of inactive pro-enzymes, interaction with specific components of the extracellular matrix and especially by endogenous tissue inhibitors of MMPs (TIMPs). In periodontal therapy have been administered low-dose doxycycline (LDD) therapy as an adjunct to scaling and root planning, because for the properties of inhibiting the activity of MMPs. In this study, important aspectsof the MMPs were reviewed, discussing the role of TIMPs and synthetic inhibitors of metalloproteinases, the use of LDD, as well as non-steroidal anti-inflammatory drugs in periodontal therapy. Since the MMPs are actively involved in the destructive process of periodontal disease, it is important the use of synthetic inhibitors of these enzymes in periodontal therapy with the aim of minimizing the destruction of the periodontium.

Repair of furcal perforation with mineral trioxide aggregate: long-term follow-up of 2 cases.

Previous studies have demonstrated the efficacy of mineral trioxide aggregate (MTA) in repair of furcal perforation. In this article, the use of MTA in treating 2 cases of furcal perforation (accidental and caries-related) and subsequent long-term follow-up are described.

Estudo clínico do uso coadjuvante de clorexidina ou de metronidazol na forma de gel durante a instrumentação subgengival / Chlorhexidine and metronidazole gel during subgingival instrumentation: a randomized clinical trial

O objetivo deste trabalho foi avaliar o uso coadjuvante de um gel de clorexidina a 1 por cento, gel de metronidazol a 10 por cento ou gel placebo, aplicados no meio subgengival antes e imediatamente após os procedimentos de raspagem e alisamento radicular em 10 pacientes com doenças periodontal. Índice de placa, sangramento à sondagem, profundidade clínica a sondagem e nível de inserçäo clínico foram avaliados no início do experimento (tempo 0) e após 1, 3 e 6 meses. Os resultados demonstraram reduções estatisticamente significantes em todos os parâmetros clínicos avaliados em relaçäo ao tempo 0, porém sem diferenças entre os grupos experimentais. Desta forma, os produtos avaliados näo promovem benefícios adicionais em relaçäo à terapia mecânica convencional, quando empregados no meio subgengival. Novas formas farmacêuticas devem ser estudadas, no sentido de proporcionar a liberaçäo controlada dos agentes antimicrobianos, mantendo-se níveis elevados da droga por períodos prolongados no interior da bolsa periodontal

Home care: the next frontier of pediatric practice.

An overview of pediatric home care issues reveals the breadth and scope of services available to permit pediatricians to provide care at home. This care option has undergone explosive growth and represents one of the fastest-growing health expenditures. Paradoxically, direct physician involvement in the home has been limited during this expansion because of the way home care has been designed and organized with inadequate reimbursement for physician participation, and lack of awareness by, and education of, physicians concerning their roles and responsibilities. The rationale for physician involvement in home care includes the need for determination and reevaluation of the medical necessity of home care services. Future changes in health care delivery and payment will encourage even more consideration of alternative care sites. Physician participation in program and protocol design will facilitate and encourage the appropriate use of the home as a care setting. For the pediatrician to know about home care requires the development of a curriculum to be implemented in academic centers for physicians-in-training and in professional associations for continuing medical education. This curriculum should enable physicians to become primary participants in home care and should lead to research opportunities to evaluate the benefits of home care.

Clinical evaluation of the macroduct sweat collection system and conductivity analyzer in the diagnosis of cystic fibrosis.

The purposes of this study were to compare sweat tests used in diagnosing cystic fibrosis (CF), as performed with the Macroduct collection system, with those utilizing the more laborious quantitative pilocarpine iontophoresis test (QPIT), and to ascertain the efficacy of the Sweat-Chek conductivity analyzer in eliminating some possibly unnecessary chloride analyses. A Macroduct sweat test was performed on one arm and a QPIT on the other on 1090 patients, 93 of whom had CF. Of these, 514 patients (43 with CF) also had a conductivity determination on the Macroduct sweat sample. All subjects were referred to the laboratory of one of us (K.B.H.) for sweat testing. Of the QPIT samples, 0.7% were inadequate, as were 6.1% of those from the Macroduct system. When sodium and chloride concentrations from the two tests were compared, the standard errors of the estimate were 3.90 and 3.85, respectively. Agreement within 8 mEq/L could then be expected with 95% confidence limits. With use of the Sweat-Chek analyzer, no patient with CF was found to have a conductivity of less than 90 mmol/L, whereas 430 (91%) of the non-CF subjects had a conductivity of less than 50 mmol/L. None of those 430 subjects had a sweat chloride value > 32 mmol/L. We conclude that the Macroduct collection system provides results equally as satisfactory as those provided by the QPIT and that the Sweat-Chek analyzer frequently eliminates the necessity of measuring chloride concentrations.