Analysis of adhesive interface in root canals irradiated by Er,Cr:YSGG laser after luting a fiber post

This study evaluated the effect of Er,Cr:YSGG laser on the root canal dentin after luting a fiber post. Twenty‐four bovine teeth roots were prepared using NiTi instruments and filled with Sealer 26 and gutta‐percha. Post spaces were prepared and roots were distributed according to dentin treatment (n = 8): 2.5%NaOCl (group control), Er,Cr:YSGG laser (1.5 W, 20 Hz, 20 s) (group test 1) or 2.5%NaOCl + Er,Cr:YSGG laser (group test 2). Fiber posts were luted using adhesive cement (Rely X U200, 3M) and roots were prepared to confocal laser scanning microscopy (CLSM) and scanning electron microscope (SEM). The morphology of interface, thickness of cement, and the gaps and tags were analyzed. Non‐parametrical data for thickness of cement were submitted to Friedman and Kruskall–Wallis tests (α = 0.05) and parametrical data for gaps to ANOVA (α = 0.05). CLSM of the cement thickness and gaps revealed no significant difference in surface treatment (NaOCl, Er,Cr:YSGG laser and NaOCl + Er,Cr:YSGG laser) (p > .05) and canal thirds (cervical, middle, and apical) (p > 0.05). SEM showed tags and a residual layer of cement adhered to dentin, mainly in laser‐irradiated specimens. The pretreatment of root canal with Er,Cr:YSGG laser previously to luting the fiber post with a self‐adhesive cement did not influence the cement thickness and gaps but affected the dentin interaction.     

Induction of adaptive response <i>in utero </i>by ionizing radiation: A radiation quality dependent phenomenon

Investigation on possible induction of adaptive response (AR) by high-liner energy transfer (LET) particleradiation for protection against low-LET photon radiation-induced detrimental effects has not yet been performed inutero. This study verified if an AR could be induced by high-LET particle radiation from accelerated heavy ionsagainst low-LET X-ray radiation-induced detrimental effects on fetal mice. Total body irradiation of pregnantC57BL/6J mice were performed by delivering a priming dose ranging from 10 mGy to 320 mGy of particle radiationon gestation day 11 followed one day later by a challenge dose at 3500 mGy from X-ray radiation. The monoenergeticbeams of carbon, silicon and iron with the LET values of about 15, 55, and 200 KeV/μm, respectively, were examined.Significant suppression by the priming radiation of the detrimental effects (fetal death, malformation, or low bodyweight) was used as the endpoints for judgment of a successful AR induction on gestation day 18. Existence of ARwas not observed. On the other hand, the priming dose of high-LET particle radiation, in some cases, even increasedthe detrimental effects induced by the challenge dose from low-LET X-ray radiation. Although existence of ARinduced by high-LET radiation in cultured mammalian cells in vitro and in certain tissues of laboratory mice in vivowas demonstrated, the present study did not suggest that low dose of high-LET particle radiation could induce an ARin fetal mice inutero under the setup of our experimental system.     

Item response drift in the Family Affluence Scale: A study on three consecutive surveys of the Health Behaviour in School-aged Children (HBSC) survey

Comparable data on socio-economic position (SEP) is essential to international studies on health inequalities. The Health Behaviour in School-aged Children (HBSC) has used the Family Affluence Scale (FAS) on material assets. The present study used data collected from adolescents in eight countries in 2002, 2006 and 2010, and examined the construct validity of the FAS, by focusing on changes in item responses over time. The analyses reported the changes in means in item responses, and fitted models which estimated differential item functioning (DIF), and local dependency (LD) between items. DIF and LD were analysed by Graphical Log-Linear Rasch Models (GLLRMs), and changes in the measurement properties of the FAS over time and between countries were assessed. The results showed that the FAS items have changed their measurement properties between 2002 and 2010, and caution is warranted in studies comparing the FAS between different time points.