60 research outputs found
Remineralising effects of fluoride varnishes containing calcium phosphate on artificial root caries lesions with adjunctive application of proanthocyanidin
Objectives: To evaluate the remineralising effects of fluoride (F) varnishes containing bioavailable calcium-phosphate compound (Ca-P) based remineralisation systems and 5000 ppm F toothpaste (FTP) on root caries lesions (RCLs) and the potential effects of proanthocyanidin (PA) for the treatments of RCLs when used as an adjunct to F regimens. Methods: Demineralised root dentine and a pH-cycling model were used to mimic RCLs and the oral environment. Remineralising effects of MI VarnishTM (MIV) containing casein phosphopeptide–amorphous calcium phosphate (CPP-ACP) and Clinpro™ White Varnish (CPWV) containing tri-calcium phosphate (TCP) along with FTP and PA were evaluated regarding the birefringence, elemental composition, mechanical properties and mineral density of remineralised dentine with DuraphatTM as a comparison. Results: MIV, CPWV and DuraphatTM promoted the incorporation of F into RCLs and increased mineral density but did not change microhardness of root dentine significantly. Surface microhardness increased significantly when MIV or CPWV was used with 5000 ppm FTP. Application of PA with F regimens significantly increased subsurface mineral density. When PA was applied with MIV or CPWV along with FTP, the highest ion uptake and relative mineral gain (%ΔZ) was achieved, and significant increase of microhardness was up to 30 μm depth. Generally, MIV was associated with a higher mineral content gain than CPWV. Significance: Treatment of carious root surfaces remains challenging due to the complex pathological processes and difficulty in restoring the highly organised structure of root dentine. Treatment strategies targeting both remineralisation and preservation of the dentinal organic matrix have the potential to improve the fluoride-mediated remineralisation approaches
The effects of intramuscular tenotomy on the lengthening characteristics of tibialis posterior: high versus low intramuscular tenotomy
BACKGROUND: Lengthening of soft-tissue contractures is frequently required in children with a wide variety of congenital and acquired deformities. However, little is known about the biomechanics of surgical procedures which are commonly used in contracture surgery, or if variations in technique may have a bearing on surgical outcomes. We investigated the hypothesis that the site of intramuscular tenotomy (IMT) within the muscle-tendon-unit (MTU) of the tibialis posterior (TP) would affect the lengthening characteristics. METHODS: We performed a randomized trial on paired cadaver tibialis posterior muscle-tendon-units (TP-MTUs). By random allocation, one of each pair of formalin-preserved TP-MTUs received a high IMT, and the other a low IMT. These were individually tensile-tested with an Instron(®) machine under controlled conditions. A graph of load (Newtons) versus displacement (millimetres) was generated for each pair of tests. The differences in lengthening and load at failure for each pair of TP-MTUs were noted and compared using paired t tests. RESULTS: We found 48% greater lengthening for low IMT compared to high IMT for a given load (P = 0.004, two tailed t test). Load at failure was also significantly lower for the low IMT. These findings confirm our hypothesis that the site of the tenotomy affects the amount of lengthening achieved. This may contribute to the reported variability in clinical outcome. CONCLUSIONS: Understanding the relationship between tenotomy site and lengthening may allow surgeons to vary the site of the tenotomy in order to achieve pre-determined surgical goals. It may be possible to control the surgical "dose" by altering the position of the intramuscular tenotomy within the muscle-tendon-unit
The National Lung Matrix Trial: translating the biology of stratification in advanced non-small-cell lung cancer
© The Author 2015.Background: The management of NSCLC has been transformed by stratified medicine. The National Lung Matrix Trial (NLMT) is a UK-wide study exploring the activity of rationally selected biomarker/targeted therapy combinations. Patients and methods: The Cancer Research UK (CRUK) Stratified Medicine Programme 2 is undertaking the large volume national molecular pre-screening which integrates with the NLMT. At study initiation, there are eight drugs being used to target 18 molecular cohorts. The aim is to determine whether there is sufficient signal of activity in any drug-biomarker combination to warrant further investigation. A Bayesian adaptive design that gives a more realistic approach to decision making and flexibility to make conclusions without fixing the sample size was chosen. The screening platform is an adaptable 28-gene Nextera next-generation sequencing platform designed by Illumina, covering the range of molecular abnormalities being targeted. The adaptive design allows new biomarker-drug combination cohorts to be incorporated by substantial amendment. The pre-clinical justification for each biomarker-drug combination has been rigorously assessed creating molecular exclusion rules and a trumping strategy in patients harbouring concomitant actionable genetic abnormalities. Discrete routes of pathway activation or inactivation determined by cancer genome aberrations are treated as separate cohorts. Key translational analyses include the deep genomic analysis of pre- and post-treatment biopsies, the establishment of patient-derived xenograft models and longitudinal ctDNA collection, in order to define predictive biomarkers, mechanisms of resistance and early markers of response and relapse. Conclusion: The SMP2 platform will provide large scale genetic screening to inform entry into the NLMT, a trial explicitly aimed at discovering novel actionable cohorts in NSCLC
The Global Assessment of School Functioning (GASF): Criterion validity and interrater reliability
The Global Assessment of School Functioning (GASF) provides a robust estimate of a student\u27s overall level of functioning within the school environment. It is intended to capture a global metric reflecting academic, social and general behavioral functioning within the school. It is a modification of the Global Assessment of Functioning and reflects functioning across academics, interpersonal relationships, school behavior, and school participation. It was developed to allow school personnel a means to communicate the general level of student functioning without re- verting to specific issues or immediate concerns. This paper reports on the scale\u27s criterion validity and interrater reliability. Confirmations of the scale structure and descriptors were obtained using subject matter experts, who confirmed descriptor\u27s criterion validity. Vignettes were developed and then rated by 64 educators to establish interrater reliability. Strong intraclass correlations (ICC) were obtained supporting the GASF reliability (single measure absolute agreement ICC = 0.998, 95th percentile confidence interval = 0.994 to 1.00). With appropriate use, this tool has value for all school personnel as a general indicator of student functioning and as a point of student reference in school team considerations. Anecdotal evidence indicates it can be used for overall progress monitoring as well
NMR Studies of the T1z Relaxation Times of the PMSN Ferroelectric
93Nb MAS studies in the solid solution Lead Magnesium Scandium Niobate (xPMSN)have been performed to probe the microscopic nature of relaxor ferroelectricity. Using the x=0.6 concentration of PMSN, saturation recovery pulse sequence experiments were performed at various temperatures to study the longitudinal relaxation times in the system. A series of both one dimensional and two dimensional experiments were used to probe the system to determine specific features, in particular relaxation times T1z.
Using the one dimensional single quantum experiments, the four largest peaks in the spectrum were analyzed, and it was seen that there is little temperature dependence in the frequencies of the peaks, but significant temperature dependence in their relaxation times T1z. Looking at these temperature dependences allows us to conclude that the relaxor behavior is significantly dependent on the local dynamics of the ions in the crystal units.
The two dimensional triple quantum MAS experiments were performed in an attempt to improve spectral resolution, allowing us to look at the behavior of a wider peak that could not be clearly resolved in 1D spectral analysis. With the decreased signal to noise in the 2D spectra, only two peaks could be analyzed with statistical confidence. However, it was seen that these peaks were significantly separated and longer and more accurate relaxation times were obtained at 300 Kelvin
An investigation of the psychometric properties of the Global Assessment of School Functioning
Schools are increasingly held accountable for student academic and behavioral performance, and showing efficacy of these treatment efforts. The primary metric for reporting academic progress, state endorsed standardized tests, does not take into account or effectively measure discrete skills or behavioral improvement. This necessitates the development of tools efficient in quantifying students’ school-based behaviors. Mental health practitioners achieve this metric utilizing the Global Assessment of Functioning (GAF). The Global Assessment of School Functioning (GASF) is being developed to be an efficient scale used by teachers for similar means. The aim of the present study is to examine the utility of the GASF in capturing overall school functioning. This study was broken into two phases. Teacher consultants assessed content validity and validated vignettes that would be used to assess inter-rater reliability. School personnel then rated five vignettes using the GASF and responded to questions regarding their perceptions of the instrument. Correlational statistics suggested that school personnel were able to rate vignettes with substantial reliability (.877). Responses to questions relating to the raters competency and training and the raters overall impressions of the technical quality of the GASF were positive. The culminating analysis from the data presented in this study suggest that the GASF warrants further study to determine its technical properties and utility as a rating scale that school personnel can use to benchmark and progress monitor student behavior
The Biomechanical Profile of an Osseo-Integrated Rectangular Block Implant: A Pilot In Vivo Strain Analysis
Aim: To load-test the osseo-integrated rectangular block implant (RBI), measure the generated cortical peri-implant strains, and relate these findings to known human physiological parameters. Materials and methods: Two RBIs were placed into the posterior mandibular saddle in a mature greyhound dog and allowed to osseo-integrate. The half mandible (implants in situ) was mounted in a servohydraulic system. Four triple-stacked rosette gauges were placed cortically (mesial, distal, buccal, and lingual). A modified ISO-14801 protocol was used (1000 N, 300, 2 Hz, 1 h) and the generated principal strains (ep, eq) and their angular orientations (F), were calculated. Results: (1) Bucco-lingual “horizontal” dimension: dominant “horizontal” compressive stresses were on the lingual aspect and “horizontal” tensile stresses on the buccal aspect. The buccal cortex was elastically tensile-stretched, while the lingual cortex was elastically compressed. (2) Bucco-lingual “vertical” dimension: dominant vertical torsional stresses were oriented buccally and apically, with an overall buccally inclined torsional effect. This was also evidenced on the lingual aspect, where there remained high torsional rotation elements (high F and e2). (3) Mesio-distal “horizontal” dimension: dominant torsional stresses oriented as a distal-lingual “counter-clockwise” rotation. Conclusions: The applied off-axial loads generated a heterogeneous pattern of bucco-lingual and mesio-distal cortical strains, both vertically and horizontally. The short dimensioned osseo-integrated RBI design appeared to biomechanically withstand the applied loads and to maintain the strains generated to levels that were within physiological limits. More studies and statistical analyses are needed to confirm these findings
Dentin bonding performance using Weibull statistics and evaluation of acid-base resistant zone formation of recently introduced adhesives
Effects of Bleaching Agents and Tooth Mousse™ on Human Enamel Hardness
Objective: The aim of this laboratory study was to investigate the effect of three commercial bleaching agents and Tooth MousseTM containing 10% w/w casein phosphopeptide–amorphous calcium phosphate on the hardness of tooth enamel.
Methods: Sixteen human enamel specimens were exposed to one of three commercial bleaching agents with or without subsequent exposure to Tooth MousseTM. Nanoindentation was used to measure the hardness and reduced modulus before and after treatments.
Results: When bleaching materials were applied for a short period of time following the manufacturers’ instructions, there was an increase in enamel hardness and reduced modulus for some bleaching groups, with no statistically significant difference from the baseline values. After extended bleaching periods a statistically significant decrease in enamel hardness and reduced modulus was found and after applying Tooth MousseTM post-bleaching, the hardness and reduced modulus returned to close to baseline values.
Conclusion: The application of bleaching agents for an extended period of time significantly decreases enamel hardness and the reduced modulus. The application of Tooth MousseTM after bleaching was able to reestablish the baseline enamel hardness and reduced modulus, decreasing the adverse effects of bleaching enamel
Casein Phosphopeptide-Amorphous Calcium Phosphate Reduces <i>Streptococcus mutans</i> Biofilm Development on Glass Ionomer Cement and Disrupts Established Biofilms - Fig 3
<p>Representative images of <i>S</i>. <i>mutans</i> biofilm formation on Fuji VII GIC (A) and Fuji VII EP GIC (B) after 16 h growth in a flow cell system.</p
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