Potential errors and misuse of statistics in studies on leakage in endodontics.

AIM: To assess the quality of the statistical methodology used in studies of leakage in Endodontics, and to compare the results found using appropriate versus inappropriate inferential statistical methods. METHODOLOGY: The search strategy used the descriptors 'root filling' 'microleakage', 'dye penetration', 'dye leakage', 'polymicrobial leakage' and 'fluid filtration' for the time interval 2001-2010 in journals within the categories 'Dentistry, Oral Surgery and Medicine' and 'Materials Science, Biomaterials' of the Journal Citation Report. All retrieved articles were reviewed to find potential pitfalls in statistical methodology that may be encountered during study design, data management or data analysis. RESULTS: The database included 209 papers. In all the studies reviewed, the statistical methods used were appropriate for the category attributed to the outcome variable, but in 41% of the cases, the chi-square test or parametric methods were inappropriately selected subsequently. In 2% of the papers, no statistical test was used. In 99% of cases, a statistically 'significant' or 'not significant' effect was reported as a main finding, whilst only 1% also presented an estimation of the magnitude of the effect. When the appropriate statistical methods were applied in the studies with originally inappropriate data analysis, the conclusions changed in 19% of the cases. CONCLUSIONS: Statistical deficiencies in leakage studies may affect their results and interpretation and might be one of the reasons for the poor agreement amongst the reported findings. Therefore, more effort should be made to standardize statistical methodology.

Retrospective long-term evaluation of autotransplantation of premolars to the central incisor region.

AIM: This retrospective case-series study aimed to examine the long-term outcomes of autogenously transplanted premolars. METHODOLOGY: Twelve patients in whom donor premolars were used to replace maxillary central incisors lost by trauma were clinically and radiologically monitored. Standardized clinical and radiographic records were systematically obtained during the follow-up period of 14 years, to determine the influence of specific clinical criteria on the overall success rate of transplantation. RESULTS: The success rate of premolar autotransplantation in the maxillary central incisor area was 80% after 14 years follow-up. The highest success rate occurred in those teeth transplanted with two-thirds of full root development. Complete pulp obliteration was positively related to autotransplant viability, followed by root formation in the bony crypt. CONCLUSIONS: Autotransplantation of donor teeth, at the stage of ½ to ¾ of their expected root length, can provide a successful treatment solution for over 14 years.

Influence of topographical features on the fluoride corrosion of Ni-Ti orthodontic archwires.

Different manufacturing processes of Ni-Ti archwires respond differently to corrosion due to the surface conditions involved. In this study, several topographical features and their influence upon fluoride corrosion were studied. Four topographies (smooth, dimple, scratch, and crack) according to the main surface defect were characterized (n = 40). Static corrosion tests were performed in artificial saliva with fluorated prophylactic gel (12500 ppm) for 28 days. The surface was characterized by SEM and laser confocal microscopy. Standard electrochemical corrosion (open circuit potential, corrosion potential and corrosion current density) was performed. Statistical analysis was carried out using the ANOVA test (α ≤ 0.05). An increase was observed in the surface defects and/or roughness of the cracked and scratched surfaces. These defects produced an important increase in corrosion behavior. The best surfaces for the orthodontic archwires were the smooth and dimpled surfaces, respectively. The increase in defects was independent of roughness. Manufacturing processes that produce surface cracks should be avoided in orthodontic applications.

Performance of laser fluorescence for detection of occlusal dentinal caries lesions in permanent molars: an in vivo study with total validation of the sample.

The objective of this in vivo study was to evaluate the performance of a laser fluorescence device in detecting dentinal caries in noncavitated occlusal surfaces. The sample included 102 first and second permanent molars, selected according to the criteria of Ekstrand et al. [Caries Res 1997;31:224-231]: 46 not suspected of having dentinal caries (score: 0-2) and 56 under suspicion (score: 3-4). Once measured by laser fluorescence, all were validated by fissurotomy (gold standard). To avoid ethical questions, the 46 teeth (score: 0-2) used were to serve as abutments for a fixed-fixed bridge. Visual inspection performed well, showing a sensitivity and specificity of 0.93 and 0.88, respectively. Laser fluorescence had an area under the receiver operating characteristic curve of A(z) = 0.85. The cutoff point with the highest sensitivity and specificity was 20, with a sensitivity and specificity of 0.89 and 0.75, respectively.

Adhesión bacteriana a biomateriales / Bacterial adhesion to biomaterials

En términos generales, para la adhesión bacteriana, influyen cuatro elementos: material, microorganismos, antimicrobianos y mecanismos de defensa. La influencia del material es más importante en los estadios iniciales de la adhesión, pudiendo influir el mismo material, su rugosidad o su energía superficial, si es que existe una influencia del material en la adhesión bacteriana, esta reside en las características de la película adquirida y en la especificidad de las proteínas adsorbidas salivares (receptores), que puedan ser condicionadas por la composición del material o por las características de superficie de este (AU)

In general terms, there are four elements which influence on bacterial adhesion: the material, the micro organisms, antimicrobials and defence mechanisms. The influence of the material is more relevant at the initial states of adhesion where the proper material, its roughness or its superficial energy can have some influence. If there is some influence of the material in the bacterial adhesion, it relies on the features of the acquired film and on the specificity of the adsorved salivary proteins (receptors), which can be influenced by the composition of the material or the characteristics of its surface (AU)

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

Objetivo: El objetivo de este estudio es describir cual es el comportamiento de la luz (..) (AU)

Introduccion: The target of this study is to describe light behavior through (..) (AU)