Conformación de conductos de doble curvatura con sistemas rotatorios de lima única / S-shape root canal shaping with one-file rotary systems

Objetivo. Comparar la modificación de conductos simulados con doble curvatura después de su preparación con 4 sistemas de lima única. Material y métodos. Se usaron 40 bloques de resina con conductos simulados de doble curvatura y divididos en 4 grupos (ni=10). Los bloques fueron preparados hasta una lima 25 usando los sistemas Reciproc (R25), Wave One Gold (Primary), One Shape y F360 (25). Se obtuvieron imágenes pre- y post-instrumentación y se superpusieron para su análisis. Se dividió la doble curvatura en 11 niveles. Se calculó la distancia desde la pared no instrumentada hasta la instrumentada. Para comparar el ensanchamiento del conducto en cada nivel se utilizó el test ANOVA, las comparaciones dos a dos se hicieron mediante el test de Tukey. El nivel de significación se estableció en p<0,05. Resultados. Todos los sistemas de lima única estudiados modifican de manera importante la curvatura apical. Wave One Gold ensanchó más en la pared interna de la curvatura apical, manteniendo un ensanchamiento más proporcional en la curvatura coronal; mientras que F360 removió más material desviando el conducto hacia la parte interna en ambas curvaturas, siendo estas diferencias estadísticamente significativas. Conclusiones. La morfología del conducto, tras instrumentación, se mantiene más fiel a la forma inicial en los sistemas Wave One Gold y One Shape

Objective. To compare the modification of simulated double curvature root canals after preparation with four single file systems. Material and methods. Forty resin blocks with simulated double curvature canals were divided into four groups (n=10), respectively instrumented to file size 25 using the Reciproc (R25), Wave One Gold (Primary), One Shape and F360 systems (25). Pre- and post-instrumentation images were obtained and overlapped for analysis. The double curvature was divided into 11 levels. The distance from the non-instrumented to the instrumented wall was calculated. Comparison of canal widening at each level was made using analysis of variance, with the Tukey test for two-by-two comparisons. Statistical significance was considered for p<0.05. Results. All the studied single file systems produced important modifications of the apical curvature. Wave One Gold resulted in greater internal wall widening in the apical curvature, with more proportional widening in the coronal curvature. In comparison, the F360 system removed more material, deviating the canal towards the internal portion in both curvatures - the differences being statistically significant. Conclusions. Canal morphology after instrumentation was seen to more closely reproduce the initial morphology when using the Wave One Gold and One Shape systems

New culture media for the isolation of Streptococcus mutans and Lactobacillus in the saliva of head- and neck-irradiated patients.

UNLABELLED: The reduction in salivary flow in patients subjected to head and neck irradiation induces changes in the oral microflora and increases the risk of oral mucosal infections. The frequent presence of fungi, particularly Candida, in the oral environment of these patients complicates identification of the most important cariogenic bacteria with the commercial CRT Bacteria (Ivoclar Vivadent) culture media. Such identification is important for the application of chemical measures to control cariogenic bacteria in these patients, since it has been shown that simple fluoride application is unable to control caries in this population. OBJECTIVE: The aim of this study was to obtain a simple medium that inhibits Candida spp. growth and allows the specific growth of Streptococcus mutans and Lactobacillus spp. Thus, reliable counts of cariogenic species can be achieved. MATERIALS AND METHODS: Stimulated saliva samples from 30 head- and neck-radiotherapy patients were seeded in commercial CRT Bacteria culture medium and in two different media designed by our group: mitis salivarius bacitracin agar (MSBA), containing 5% potassium tellurite and fluconazole 64 microg/ml (MSBTPF) for the isolation of Streptococcus; and Man, Rogosa and Sharpe (MRS) agar, containing bacitracin 0.2 U/ml and fluconazole 32 microg/ml (MRSBF) for the isolation of Lactobacillus spp. RESULTS: Candida growth was inhibited 100% in the media developed in this study. In all the samples seeded, growing of colonies in MRSBF was identified as Lactobacillus, while in CRT Bacteria for Lactobacillus spp. this species was only isolated in 48.1% of the samples. S. mutans was identified in 71.4% of the colonies that grown in MSBTPF medium, while in CRT Bacteria for S. mutans, this species was only identified in 35% of the colonies obtained. CONCLUSION: The culture medium developed in the present study was able to inhibit the 100% of Candida spp. growth. These new media permit reliable counts of cariogenic bacteria in irradiated patients.