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Biomedical subjects

David Watts

Publications and source records attributed to David Watts.

9 recordsLinked to original sources
PubMed2006

3D-marginal adaptation versus setting shrinkage in light-cured microhybrid resin composites.

PURPOSE: To comparatively evaluate the 3D-marginal adaptation to dentine versus shrinkage strain of two light-cured microhybrid resin composites. METHODS: Dentine cavities (Ø: 2 mm; h: 1 mm; n=2x4) were prepared, filled with a single layer of EsthetX and Premise resin composites, respectively, without any adhesive cavity pre-treatment, and light-cured for 40s at 750 mW/cm2. All the specimens were imaged by computerized X-ray microtomography. Sequential sections (n=11) at 8.09 pixel size were taken at top, middle and bottom sites of each restoration relative to the axial wall and the interfacial micro-void volume fraction (%VF) was calculated. Shrinkage strain (%S) and strain rate (%SR) of the composites were measured by the bonded-disc method (n=4). The results of %VF per material and restoration site were subjected to statistical analysis by 2-way ANOVA and Tukey's test, whereas the results of %S and %SR were analysed by t-test (p=0.05). Regression analysis was performed to determine correlations between %PF and %S, %S(R). RESULTS: The results of %VF at top (t), middle (m) and bottom (b) restoration sites were (%, mean+/-S.D.): EsthetX 0.84+/-0.11 (t), 0.80+/-0.32 (m), 6.74+/-5.12 (b), Premise 0.99+/-0.24 (t), 0.92+/-0.38 (m), 1.72+/-0.97 (b). The results of %S were (%, mean+/-S.D.): EsthetX 2.60+/-0.29, Premise 1.91+/-0.10 and of %SR were (%, mean+/-S.D.): EsthetX 1.47+/-0.04, Premise 1.18+/-0.02. %VF(b) of EsthetX showed the highest values within and between the testing groups (p<0.05). %S and %S(R) values of EsthetX were significantly higher from Premise (p<0.05). Strong positive correlations were documented between %VF(b)-%S (r=0.843) and %VF(b)-%SR (r=0.943). CLINICAL SIGNIFICANCE: The results confirmed a positive correlation between setting shrinkage and interfacial gap volume at bottom sites of light-cured microhybrid composite restoration due to differential shrinkage. Shrinkage strain rate seems to be a more sensitive factor in determining percentage volume of interfacial porosity at bottom restoration sites.

Analysis of Variance↗
PubMed2006

Outcomes after supratherapeutic escitalopram ingestions.

Escitalopram (ESC) is a new selective serotonin reuptake inhibitor (SSRI) used in the treatment of depression. There are limited data regarding accidental and intentional ESC exposure. We conducted a retrospective chart review of isolated ESC ingestions reported to our regional poison center during 2003-2004. Twenty-eight patients met inclusion criteria. The average patient age was 28.1 years (range 2-75 years) and the average amount of ESC ingested was 62.5 mg (range 5-300 mg from 19 cases). The most common formulation ingested was the 20-mg tablet. There were eight accidental ingestions and 20 intentional overdoses. Six of the eight accidental ingestions were observed at home with follow-up in 24 h, and no adverse outcomes were reported. The other two accidental overdoses were observed in the Emergency Department (ED) and discharged home with no adverse events reported. Nineteen of the intentional overdoses were observed in the ED for approximately 4-6 h and discharged home or to an inpatient psychiatry ward. One of the intentional overdose patients was admitted for persistent lethargy, but had a good outcome. ESC toxicity can theoretically be life threatening, but no patients in our series had adverse sequealae after accidental or intentional overdose.

Adolescent↗
PubMed2005

Surface characterization of modern resin composites: a multitechnique approach.

PURPOSE: To characterize the surface properties of some modern resin composites employing a series of physicochemical methods. METHODS: Specimens from three microhybrid (Palfique Estellite-PE, Z250 Filtek-ZF, Tetric Ceram-TC) and one nanofilled (Supreme Filtek-SF) conventionally photo-cured resin composites polished with Soflex disks were studied for the following properties: Surface chemical composition and degree of C=C conversion (FTIR), surface energetics (contact angles), surface texture (AFM), surface roughness (AFM, stylus profilometry) and gloss (60 degrees-, 20 degrees-angle specular gloss). RESULTS: Polar and non polar molecular groups were identified in all products including NH and CONH (SF, ZF, TC). SF and ZF demonstrated higher conversion than PE and TC (P< 0.05). No significant differences (P> 0.05) were found in critical surface tension, total work of adhesion and its polar and dispersion components, the latter being the highest in all products. AFM showed the smoothest surface texture in PE. The ranking of Sa, Sq, Ra and Rz roughness parameters was PE ZF>TC, P< 0.05) were more sensitive than 60 degree-angle measurements (PE, SF>TC, P< 0.05) in revealing gloss differences. A positive correlation was found between Sa and Ra and a negative one between Sa and 20 degree-angle gloss.

Adhesiveness↗
PubMed2003

Azathioprine and anti-TNF alpha therapies in Crohn's disease: a review of pharmacology, clinical efficacy and safety.

Crohn's disease (CD), a chronic relapsing inflammatory condition of the intestines, is a common cause of gastrointestinal morbidity in young people. Although the aetiology of CD is unknown, host, genetic and environmental influences are clearly important. Glucocorticoids remain the mainstay of treatment for active CD, however only two-third of patients will respond and side effects are considerable. Surgery is often undesirable or impracticable and therefore alternative medical strategies have been sought. In recent years, there has been much interest in two areas of IBD therapy-the use of established immunomodulators, and the development of novel biological therapies. In this review, we have selected two areas of particular controversy-the use of purine analogues (azathioprine (AZA) and 6-mercaptopurine (6-MP)) and the introduction of anti-tumour necrosis factor alpha (TNFalpha) therapy and have examined the data for efficacy, safety and tolerability of these medications.

Animals↗
PubMed2002

An institutional experience with laparoscopic gastric bypass complications seen in the first year compared with open gastric bypass complications during the same period.

BACKGROUND: Complication rates for laparoscopic bariatric surgery remain in evolution. METHODS: Single institution review of the initial year's experience with laparoscopic gastric bypass compared with open gastric bypass complications for the same period. RESULTS: There were 20 laparoscopic and 52 open gastric bypass procedures. Five laparoscopic patients had major complications. There were 4 anastomotic leaks. Nine open bypass patients had major complications, with 2 leaks. Leak rate was 20% for the laparoscopic group and 4% for the open group. All leaks in both groups led to substantial morbidity. There were two deaths, one in each group. The laparoscopic death was from postleak sepsis. CONCLUSIONS: Gastric bypass, whether done open or laparoscopically, has significant surgical risk. Complication profiles differed between the two groups. Anastomotic leaks were significantly more frequent in the laparoscopic group, probably related to the learning curve. There is a continued need for open surgery in many bariatric patients.

Adult↗