Laser-induced fluorescence in the diagnosis of pulp exposure and the influence of residual dentin thickness: An in vivo study.

PURPOSE: To clinically (a) determine whether laser-induced fluorescence (LIF) was able to assess pulp tissue health or disease in situations of pulp exposure; (b) evaluate the influence of different pulp tissue conditions upon LIF through dentin thicknesses of ≤1 mm; and (c) explore possible differences between the diagnostic performance of quantitative (q) and qualitative (ql) LIF. METHODS: 98 healthy subjects were scheduled for the treatment of caries. Three groups were established according to pulp tissue condition: Group A (n=30 teeth) (deep caries with healthy pulp tissue); Group B (n=30 teeth) (pulp necrosis); and Group C (n=30 teeth) (irreversible symptomatic acute pulpitis). The carious lesions were eliminated, and q and ql LIF measurements were made at two levels: measurement in dentin at < 1 mm from the pulp (A-D); and direct pulp exposure measurement (A-LP). In healthy pulp tissue at level A-LP, eight teeth with accidental pulp exposure were used. The Kruskal-Wallis test was used to evaluate the statistical significance of the differences in LIF readings among the three groups. The diagnostic performance of q and ql LIF in application to pulp tissue health or disease was assessed by calculating the sensitivity and specificity of the two tests at level A-LP. RESULTS: A significant correlation was observed between acute pulpitis and an increase in the q LIF values at level A-D (P= 0.004), but with no correlation to healthy pulp. Quantitative and qualitative LIF may be useful in diagnosing pulp tissue health or disease in situations of pulp exposure (A-LP).

Performance of laser fluorescence for the detection of enamel caries in non-cavitated occlusal surfaces: clinical study with total validation of the sample.

PURPOSE: To evaluate the clinical performance of a laser fluorescence device in detecting enamel caries in non-cavitated occlusal surfaces. METHODS: The sample included 96 first and second permanent molars, selected according to the criteria of Ekstrand: 44 not suspected of having dentin caries (score: 0-2) and 52 under suspicion (score: 3-4). Once measured by laser fluorescence, all teeth were validated by fissurotomy (gold standard). To avoid ethical questions, the 44 teeth (score: 0-2) used were to serve as abutments for a fixed dental prostheses. Following fissurotomy, the 52 teeth with suspected caries were treated with resin composite restorations. Kruskall-Wallis statistical analysis (P<0.05) was used. RESULTS: Laser fluorescence showed an area under the Receiver Operating Characteristic (ROC) curve of Az = 0.803 for enamel caries. The cut-off point with the highest sensitivity and specificity was 15, with a sensitivity and specificity of 0.97 and 0.63, respectively. Values under 10 indicated healthy teeth.

Statistical errors in microleakage studies in operative dentistry. A survey of the literature 2001-2009.

The aim of this study was to assess the literature on microleakage of direct restorations in operative dentistry indexed in the ISI Web of Science, in order to assess the robustness of the statistical methodology used. Our database included 226 scientific papers (published between 2001 and 2009 in 22 journals) from the journal citation report categories 'Dentistry, Oral Surgery and Medicine' and 'Materials Science, Biomaterials'. We reviewed all articles to find potential mistakes that are commonly made at different stages in the scientific research process. Microleakage was assessed quantitatively in 50 (22.2%) studies and qualitatively in 176 (77.8%) studies. In all studies reviewed the statistical methods used were appropriate for the category attributed to the outcome variable, but in 13% of the total, the chi-square test or parametric methods were inappropriately used afterwards. When the appropriate statistical methods were applied in studies that had originally employed inappropriate methods to analyse their data, and in which the authors provided raw data, an alteration of the conclusions was necessary in 15.4% of these re-analysed studies. This survey also showed that the statistical methodology applied varies considerably for similar experimental designs. This could have an effect on statistical results; hence, a more standardized methodology should be implemented.

Critical diameter of apical foramen and of file size using the Root ZX apex locator: an in vitro study.

INTRODUCTION: An evaluation was made of the accuracy of the Root ZX apex locator (J. Morita Corp, Tokyo, Japan) in widened foramina, considering the existing controversy over this issue in the literature. METHODS: Ten single-root teeth were embedded in an alginate mold. The foramina were widened from 0.6 mm to 1.0 mm. The measurements were taken with all possible file sizes ≥#10. The statistical accuracy of the Root ZX was calculated for the different diameters and for the influence of file size. RESULTS: The accuracy of the Root ZX apex locator with a range of error of ±0.5 mm was 87% in an apical foramen size of 0.6 mm and 84% using files size 45 or larger in an apical foramen size of 0.7 mm. With a tolerance of ±1 mm, the accuracy was 99% in an apical foramen size of 0.6 mm, 98% using files size 45 or larger in an apical foramen size of 0.7 mm, and 95% using files size 70 or larger in an apical foramen size of 0.8 mm. In the rest, accuracy was not certain. The measurements taken with smaller files were shorter. There were no cases of overestimation of the working length. CONCLUSIONS: The Root ZX apex locator was accurate for an apical size of 0.6 mm, independently of the file size; between 0.7 to 0.8 mm, we should adjust the files to the foramen, whereas above size 0.9 mm the locator is not accurate. The results show that the accuracy of this electronic apex locator is gradually lost as the foramen widens. Considering the stable conditions of in vitro studies, our findings advise caution in clinical application of the locator.

Developments in polymerization lamps.

Polymerization shrinkage of composite resins and the consequent stress generated at the composite-tooth interface continue to pose a serious clinical challenge. The development of high-intensity halogen lamps and the advent of curing units providing higher energy performance, such as laser lamps, plasma arc units, and, most recently, light-emitting diode (LED) curing units, have revolutionized polymerization lamp use and brought major changes in light-application techniques. A comprehensive review of the literature yielded the following conclusions: (1) the most reliable curing unit for any type of composite resin is the high-density halogen lamp, fitted with a programming device to enable both pulse-delay and soft-start techniques; (2) if any other type of curing unit is used, information must be available on the compatibility of the unit with the composite materials to be used; (3) polymerization lamp manufacturers need to focus on the ongoing development of LED technology; (4) further research is required to identify the most reliable light-application techniques.

Influence of apical constriction diameter on Root ZX apex locator precision.

Small-diameter hand files are systematically used to determine the initial working length and to establish patency of the root canal. In wide canals, electronic apex locator accuracy might be influenced by file size. This article reports on a study to assess the influence of apical constriction diameter on the precision of the Root ZX apex locator by using files of varying diameter on teeth with 3 different degrees of apical widening: 0.37, 0.62, and 1.02 mm. Ten extracted single-root teeth, stored in saline solution at 37 degrees C, were sectioned at the enamel-cement junction and embedded in an alginate mold. Initial working length (L0) was determined with a #10 Kerr file, and canals were irrigated with either 50% citric acid or 5.25% sodium hypochlorite. To assess the ability of the locator to identify the narrowest area of the root canal as constriction diameter increased, the canal was progressively widened by insertion of files of increasing diameter (10-100) at a point L0+1 mm. After each enlargement, the working length (L) was redetermined, with files from #10 (L10) up to the file used for widening. Comparison of statistical results was based on the difference between final working length and initial length (L10) for each apical width. Statistical analysis was carried out with analysis of variance test for comparison of means. Results showed that at apical constriction widths of 0.37 and 0.62 mm, there was no significant difference between initial working lengths as determined by a Kerr #10 file and final working lengths after widening with files of up to #60. In those teeth whose apical width had been increased to 1.02 mm, there was no statistically significant difference between initial and final working lengths as measured by files from #10-#25; however, significant differences were apparent between #10 and #30, #35, or #40 (P<.05), and the degree of significance increased considerably (P<.001) for files #45 or greater. These results suggest that Root ZX apex locator precision varies as a function of apical constriction diameter.

Comportamiento de la intesidad de la luz de las lámparas halógenas y leds a través de la resina compuesta / No disponible

Objetivo: Describir el comportamiento de la Intensidad de la Luz generada por lámparas Halógenas y LEDs a medida que atraviesan laresina compuesta. Material y metodo: Utilizamos dos lámparas LEDs con intensidades de radiación de 350 y 210 mW/cm2 y dos lámparas Halógenas con intensidades de radiación de 460 y 300 mW/cm2 . Realizamos mediciones de intensidad mediante radiómetros en muestras entre 0.5, 1,1.5, 2, 2.5 y 3 mm de espesor. Resultados: El descenso de la intensidad es proporcional a la Intensidad de Salida y similar para todas las lámparas, excepto para la LEDs de mW/cm2 que es algo mayor. Conclusiones: El comportamiento de la Intensidad de Radiación a distintos planos de profundidad es similar para las lámparas Halógenas y LEDs estudiadas (AU)

Objective: To describe behaviour of light intensity trough a composite resin when it is generated by an halogen lamp and a LED lamp. Material and method: We used two LED lamps with radiation intensities of 350 and 210 mW/cm2 and two halogen lamps with radiation intensities of 460 and 300 mW/cm2. With a radiometer we measure light radiation every 0.5mm between 0.5mm and 3mm depth. Results: decrease in light intensity was proportional to intensity output and similar in all lamps, except for the LED lamp with 350mW/cm2 output in which it is larger. Conclusion: Intensity radiation behaviour trough composite is similar for halogen lamps and LED´s (AU)