Biomedical subjects

R Newcombe

Publications and source records attributed to R Newcombe.

At least 19 recordsLinked to original sources

PubMed1997

Microleakage of Diaket and amalgam in root-end cavities prepared using MicroMega sonic retro-prep tips.

The in vitro sealing ability of the root-canal sealer Diaket when used as a root-end filling material was compared with that of amalgam using linear micro-leakage of Indian ink. Eight groups of 20 extracted teeth each were formed, plus 12 control teeth as follows: 1) root-end resection of 45 degrees bevel, root-end cavity preparation with an 008 round bur, amalgam root-end filling; 2) 45 degrees bevel, bur, Diaket; 3) 45 degrees bevel, using a sonic retro-prep tip, amalgam; 4) 45 degrees bevel, sonic, Diaket; 5) no bevel, bur, amalgam; 6) no bevel, bur, Diaket; 7) no bevel, sonic, amalgam; 8) no bevel, sonic, Diaket. Root-end cavity depths of 3 mm were prepared. Specimens were immersed in Indian ink for 2 weeks. The teeth were demineralized, rendered transparent and linear dye penetration recorded. Results showed that Diaket provided a superior seal to amalgam irrespective of the root-end preparation. The degree of bevel of the resected root-end did not influence leakage. Sonic instrumentation resulted in a larger root-end cavity than with burs.

Apicoectomy↗

PubMed1997

The comparative effect of acidified sodium chlorite and chlorhexidine mouthrinses on plaque regrowth and salivary bacterial counts.

Acidified sodium chlorite (ASC) is recognised as a highly potent, broad spectrum antimicrobial system that has been successfully developed for uses in veterinary, food processing and medical device fields. The current studies aimed to investigate the persistence of antimicrobial action and plaque inhibitory properties of 3 ASC mouthrinses by comparison with positive control, chlorhexidine 0.12%, and placebo control, water, rinses. Both studies were randomised, double-blind, cross-over 5-cell designs balanced for carryover. The 1st study involved 15 healthy subjects who immediately before and at 30, 60, 180, 300 and 420 min after rinsing provided 2 ml saliva samples. The samples were immediately processed for total anaerobic bacterial counts recorded after 96 h incubation. Washout periods were a minimum of 3 days. The second study involved 20 healthy subjects who on day 1 of each study were rendered plaque free, suspended normal oral hygiene methods and commenced rinsing twice daily with the allocated rinse. On day 5, plaque was scored by index and area after disclosing with erythrosin. Washout periods were 2 1/2 days. The 3 ASC and chlorhexidine rinses produced similar reductions in salivary bacterial counts which remained significantly below the placebo control to 7 h. There were no significant differences between ASC and chlorhexidine rinses except at 30 and 60 min when significantly greater reductions were produced by 2 ASC rinses compared to the chlorhexidine rinse. Plaque indices and areas were considerably and significantly lower with the ASC and chlorhexidine rinses compared to the placebo rinse. There were no significant differences between plaque scores for the 3 ASC rinses and the chlorhexidine rinse, although for 2 ASC rinses plaque scores were lower than for the chlorhexidine rinse. The results indicate that the 3 ASC rinses have equivalent plaque inhibitory action to chlorhexidine as a rinse. Similar to chlorhexidine, the plaque inhibitory action of the rinses appears to be derived from a persistence of antimicrobial action in the mouth.

Anti-Infective Agents, Local↗

PubMed1997

A 4-day plaque regrowth study comparing an essential oil mouthrinse with a triclosan mouthrinse.

The adjunctive use of antiplaque mouthrinses with normal oral hygiene procedures may produce a significant beneficial effect on gingival health. At present, numerous products are available with various claims for efficacy. Although for many of these products, well-controlled studies have been carried out comparing the products, against a negative control or placebo, very few studies have been carried out directly comparing the efficacy of one commercial product with another. In this observer-blind, 4-day plaque regrowth, crossover study, the efficacy of a commercial triclosan mouthrinse was compared to that of an essential oil mouthrinse and 2 placebo controls. Starting from zero plaque at the commencement of each trial period, 32 volunteers used only the allocated rinses as the method of oral hygiene over 4 days, and on the 5th day returned for measurement of plaque index and area. The essential oil rinse produced a plaque reduction of 52% for plaque area and 17% for plaque index compared to its placebo, whilst the triclosan rinse produced a 45% reduction for plaque area and 12% reduction for plaque index against its placebo. Analysis of variance and construction of 95% confidence intervals showed that both active rinses significantly reduced plaque compared to their respective placebo. In addition, the essential oil rinse significantly reduced plaque compared to the triclosan rinse for plaque index but not for plaque area. The findings of this study would suggest that of the 2 rinses, the essential oil rinse would be expected to be more effective at reducing plaque formation in the longer term.

Adult↗

PubMed1997

Studies on stannous fluoride toothpaste and gel (2). Effects on salivary bacterial counts and plaque regrowth in vivo.

There has been a resurgence of interest in stannous fluoride (SF) products in particular to provide oral hygiene and gingival health benefits. The aim of this study was to assess the persistence of antimicrobial action of a number of SF formulations in the mouth and relate these to plaque inhibitory activity. The formulations were 2 SF toothpastes (SF1, SF2), 2 SF plus stannous pyrophosphate toothpastes (SFSP1, SFSP2), a SF gel (G), a NaF toothpaste (C) and saline (S) as control. Both studies involve 2 different groups of 21 healthy dentate volunteers. The studies were single, blind, randomised, crossover designs balanced for residual effects, with a minimum 2 1/2 day washout period. Salivary bacterial counts were determined before and to 7 h after a single rinse with the formulations. Plaque regrowth from a zero baseline (day 1) was measured by index and area on day 5, after 2x daily rinsing with slurries of the formulations or saline. For bacterial counts, highly significant treatment differences were found. Bacterial counts were variably reduced by all treatments to 30 min then showed a variable rate of return towards baseline. All test agents were significantly better than S at some timepoints. The order for greatest persistence of action downwards was; (1) SFSP2; (2) SFSP1, G, and SF1; (3) SF2; (4) C; (5) S. Highly significant differences in plaque regrowth between treatments were found with similar mean ordering of efficacy as for salivary bacterial counts from most effective downwards namely; (1) SFSP1 and SFSP2; (2) SF1; (3) SF2; G and C; (4) S. The results were consistent with a parallel study measuring tea staining in vitro, whereby formulations causing the most staining produced the greatest persistence of action and plaque inhibitory activity. This suggests the availability of stannous ions was important for the clinical effects. It is concluded that stannous ions can enhance the plaque inhibitory action of toothpaste via a persistent antimicrobial action.

Analysis of Variance↗

PubMed1997

A urine analysis method suitable for children's nappies.

BACKGROUND: Urinary tract infection in infancy continues to be underdiagnosed, despite its association with renal scarring and thus hypertension, renal failure, and other sequelae. Low ascertainment of urinary tract infections reflects the many difficulties in establishing a diagnosis, some of which could be eliminated by a simple, reliable method for preliminary investigation of children's urine. AIM: To assess the accuracy of a new, simple method for testing urine for nitrite and leucocyte esterase, which could be applied to children in primary care. METHODS: An in vitro study was carried out to compare the results of conventional urine analysis with urine analysis on urine soaked on to panty-liners, and with the laboratory investigation. Two urine analysis stick types were used (Boehringer Mannheim Nephur sticks and Bayer Multistix 8SG) and two brands of panty-liners. Analysis examined evidence of agreement and bias for different methods in addition to sensitivity, specificity, and negative predictive values for urine analysis. RESULTS: Pressing urine analysis test sticks on to panty-liners soaked with urine achieved consistent results compared with the results of conventional dipstick urine analysis. At a prevalence of 21.8%, sensitivity and negative predictive values of urine analysis for laboratory confirmed urinary tract infection were 94% and 98%, respectively, for Boehringer sticks, and 76% and 93%, respectively, for Bayer sticks. At prevalences of 5% and 1% (prevalences that could be expected in primary care) Bayer sticks had negative predictive values of 98.7% and 99.7%, respectively, and Boehringer sticks had values of 99.6% and 99.9%, respectively. CONCLUSIONS: Testing urine on panty-liners is accurate compared with conventional urine analysis. It may be possible to apply this method to testing unwell children presenting in primary care to identify those who require microbiological urine culture to confirm or eliminate a diagnosis of urinary tract infection.

Adolescent↗

PubMed1996

Cardiff puerperal mood and hormone study. III. Postnatal depression at 5 to 6 weeks postpartum, and its hormonal correlates across the peripartum period.

BACKGROUND: We assessed associations of mood at 5-6 weeks postpartum with peripartum saliva cortisol and progesterone profiles. METHOD: A prospective study involved 120 primiparous women free of major marital, socioeconomic and health problems, who collected saliva twice daily from 2 weeks before delivery to day 35 postpartum. This allowed intensive characterisation of cortisol and progesterone profiles. At the conclusion of the study, mood was assessed according to standard criteria. RESULTS: Seven women developed major depression according to DSM-III-R criteria. No associations emerged between progesterone and mood at 5 to 6 weeks. Lower levels of evening cortisol in the immediate peripartum period, were associated with postnatal depression. CONCLUSION: The study provides no support for the treatment strategy of progesterone augmentation following delivery, as a prophylactic against postnatal depression. The HPA axis and its associations with postnatal mood warrants further investigation.

Adolescent↗

PubMed1995

The comparative tea staining potential of phenolic, chlorhexidine and anti-adhesive mouthrinses.

Staining of teeth and mucous membranes is a well-known side-effect with chlorhexidine mouthrinses in which dietary chromogens play an important rôle. The purpose of this study was to determine whether a co-polymer anti-adhesive agent would prevent staining by a low concentration chlorhexidine solution. Additionally, the possibility that an essential oil/phenolic rinse product may cause staining was investigated. The rinses studied were the anti-adhesive alone and combined with 0.02% chlorhexidine and the essential oil/phenolic rinse. These were positioned against a positive control rise, 0.2% chlorhexidine, and a negative control rinse, water. The study was a single blind 5-treatment, randomised Latin square cross-over design, incorporating balance for carry-over effects. 15 volunteers participated and on Day 1 of each study period were rendered stain free by scaling and polishing of the teeth. Oral hygiene was suspended and 8 x per day subjects rinsed under supervision, firstly with the allocated formulation and then with 10 ml of warm black tea. On Day 4, tooth and tongue staining was scored by area and intensity (colour). A washout period of at least 3 1/2 days was permitted between treatment periods when oral hygiene was resumed. Before the study and during washouts, volunteers practised tongue brushing. Tooth and tongue staining was significantly increased with 0.2% chlorhexidine compared to the essential oil/phenolic rinse which in turn was significantly increased compared to the other 3 rinses. The antiadhesive/chlorhexidine rinse produced no more staining than the anti-adhesive or water rise. However, the parallel plaque regrowth study suggests this inhibition of staining resulted from the vitiation of the chlorhexidine activity by the antiadhesive. The methodology would appear a simple and quick way of assessing the propensity of mouthrinses to cause extrinsic staining.

Anti-Infective Agents, Local↗

PubMed1995

The comparative effects on plaque regrowth of phenolic chlorhexidine and anti-adhesive mouthrinses.

The inhibition of bacterial attachment to the tooth surface is one possible approach to plaque control. This study evaluated in vivo the plaque inhibitory action of a novel copolymer reported to have considerable antiadhesive properties in vitro. The study was a single blind, 5-treatment, randomised Latin square crossover design, incorporating balance for carry-over effects. The rinses were the antiadhesive (1%), the antiadhesive with 0.02% chlorhexidine, a 0.2% chlorhexidine rinse product, an essential oil/phenolic rinse product and water. 15 volunteers participated and on day 1 of each study period were rendered plaque-free, ceased toothcleaning and rinsed 2 x daily, under supervision, with the allocated formulation. On day 5, plaque was scored by index and area. Washout periods were 2 1/2 days. Alone or combined with chlorhexidine, the antiadhesive agent showed no effects greater than water. The chlorhexidine rinse was significantly more effective than the essential oil/phenolic rinse which in turn was significantly more effective than the other rinses.

Anti-Infective Agents, Local↗

PubMed1995

Radiological assessment of constipation.

A scoring system for faecal loading was constructed by two experienced observers using the abdominal radiographs of 20 children. Four other observers independently graded the radiographs using this system and there was a high degree of agreement between all six observers (p < 0.001), suggesting that radiological assessment of constipation can be standardised.

Adolescent↗

PubMed1994

The normalization of recreational drug use amongst young people in north-west England.

An anonymous self-report survey of drug use among a cohort of 776 14-15 year olds in North-West England was conducted at the end of 1991, aiming to estimate prevalence and profile users. Six in 10 reported being offered drugs, and 36 per cent to using drugs (20 per cent in the past month). Over half of those offered drugs had tried them. Lifetime prevalence was highest for cannabis (32 per cent), with five other drugs each being used by 10-14 per cent. Three groups identified were cannabis smokers, solvents sniffers, and stimulant/psychedelic (or dance drug) users. The population parameters of drug use were estimated at 33-40 per cent, suggesting up to 200,000 local young adults have used drugs. Most significantly, the proportion of young women being offered and using drugs and the prevalence of drug trying amongst young people in 'middle-class' schools, suggests a substantial social transformation is underway in respect of recreational drug use. The results of this survey confirm a general trend apparent in other British studies. As this cohort is tracked into the mid 1990s, the sociological implications will be significant.

Adolescent↗

PubMed1993

A 6-month home usage trial of a 1% chlorhexidine toothpaste (1). Effects on plaque, gingivitis, calculus and toothstaining.

Research and development has been aimed towards the development of toothpastes for oral hygiene and gingival health benefits. The most effective antiplaque agent to date, chlorhexidine, is difficult to formulate into active toothpaste products. Despite some encouraging findings for experimental chlorhexidine toothpastes, there are to date no commercially available products. Based on positive findings from an experimental gingivitis study, this investigation evaluated 2 chlorhexidine toothpastes, one with fluoride, as adjuncts to oral hygiene. The study was a double-blind controlled, parallel, balanced group design, extending over 6 months. A total of 297 volunteers commenced the study after screening for a minimum acceptance level of gingivitis. At baseline, 6, 12 and 24 weeks, stain, gingival, bleeding and plaque indices were recorded, together with a calculus index at 6, 12 and 24 weeks. After a baseline prophylaxis, volunteers used the allocated product 2 x per day, with no other oral hygiene instructions given. Plaque, gingival and bleeding scores improved in all 3 groups, but to an overall significantly greater extent in the active groups. However, staining and calculus indices were significantly increased in the active compared to the control group. If the local side-effects of chlorhexidine are considered to be acceptable, these chlorhexidine toothpastes could be recommended for the same clinical applications as other chlorhexidine products. The apparent compatibility of fluoride with chlorhexidine in the one product may be pertinent to caries prevention.

Adolescent↗

PubMed1993

Evaluation of a mouthrinse containing chlorhexidine and fluoride as an adjunct to oral hygiene.

Chlorhexidine and fluoride have valuable preventive roles in dental and oral diseases. There is also evidence that in caries prevention, together, they provide additive benefits. However, combined chlorhexidine/fluoride formulations have rarely been evaluated. The aim of this study was to determine whether a 0.12% chlorhexidine, 100 ppm F- mouthrinse provided adjunctive oral hygiene benefits compared to a minus active control rinse. The study was a randomised double-blind parallel design involving 102 subjects of whom 99 completed the 6 week experimental period. Subjects rinsed 2x per day for 1 min with 15 ml of the allocated rinse. Normal toothbrushing procedures were maintained throughout the study. At 6 weeks, plaque and gingivitis scores were significantly lower and the incremental reduction significantly larger in the active rinse group. However, as expected, toothstaining was significantly increased with the active rinse. It is apparent that this chlorhexidine/fluoride rinse could be used in those regimens recommended for other chlorhexidine formulations. The value of the formulation in caries prevention would seem worthy of further investigation.

Adolescent↗

PubMed1993

The effects of a chlorhexidine toothpaste on the development of plaque, gingivitis and tooth staining.

Chlorhexidine has found many uses in clinical dentistry as an antiplaque agent. To date, effective chlorhexidine-containing toothpastes have not been made available. This study was the first phase in the evaluation of a 1% chlorhexidine toothpaste, formulated to ensure a high availability of the contained antiseptic. The study was a 19-day, randomised double-blind placebo-controlled, crossover experiment al gingivitis clinical trial employing 14 healthy human volunteers. From a zero plaque and low gingivitis baseline, the development of plaque, gingivitis and dental staining was measured on days 12 and 19 of the 2 study periods. The toothpaste was used 2x a day as a slurry rinse with no other form of oral hygiene. The washout period was 21 days. The development of plaque and gingivitis was statistically and clinically highly significantly reduced during the use of the active compared to the placebo product. Conversely, dental staining was statistically and clinically significantly increased. The product deserves further evaluation for potential clinical use.

Adult↗

PubMed1993

The natural history of congenital myotonic dystrophy: mortality and long term clinical aspects.

Although the genetic basis of the congenital form of myotonic dystrophy has recently been clarified, data as to outcome in terms of life expectancy and morbidity are scanty. Life table data based on a cohort of 115 patients with a confirmed diagnosis of congenital myotonic dystrophy are presented. The data suggest a 25% chance of death before 18 months of age and a 50% chance of survival into the mid-30s. The profile of disease and complications among survivors is also charted.

Adolescent↗

PubMed1992

Glucocorticoids exacerbate kainic acid-induced extracellular accumulation of excitatory amino acids in the rat hippocampus.

Glucocorticoids (GCs) compromise the ability of hippocampal neurons to survive various insults, and do so, at least in part, by exacerbating steps in the glutamate/N-methyl-D-aspartate (NMDA)/calcium cascade of damage. As evidence, GCs impair uptake of glutamate by hippocampal astrocytes, the GC endangerment of the hippocampus is NMDA receptor dependent, and GCs exacerbate kainic acid (KA)-induced calcium mobilization. These observations predict that GCs should also exacerbate KA-induced accumulation of extracellular glutamate and aspartate. To test this, adrenalectomized rats were given replacement GCs in either the low or high physiological range. Three days later, rats were anesthetized and 1 mM KA was infused through a dialysis probe placed in the dorsal hippocampus. Extracellular amino acid concentrations in the dialysate were then assessed by HPLC. After KA infusion, high-GC rats (30 +/- 3 micrograms/dl) had significantly elevated concentrations of glutamate and aspartate compared with low-GC rats (all less than 0.95 micrograms/dl). The glutamate accumulation was due to GCs raising pre-KA concentrations, whereas the aspartate accumulation was due to GCs exacerbating the KA-induced rise. Glutamine concentrations were unaffected by KA, whereas the high-GC regimen elevated glutamine concentrations both before and after KA. Taurine concentrations rose after infusion of KA, but were unaffected by GC regime, whereas alanine concentrations were unaffected by either manipulation. Serine concentrations were unaffected by KA, but were depressed both before and after KA in high-GC rats.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acids↗

PubMed1992

The effects of antimicrobial acrylic strips on the subgingival microflora in chronic periodontitis.

This study investigated the effects of root planing and/or the placement of acrylic strips containing chlorhexidine, metronidazole or tetracycline on the composition and antimicrobial susceptibility of the subgingival flora in chronic periodontitis. 101 periodontal pockets from 73 patients were entered into 6 treatment groups which were, chlorhexidine, metronidazole or tetracycline strips, root planing, root planing followed by metronidazole strips and a control, no treatment group. Total anaerobic counts and anaerobe/aerobe ratios were estimated from samples taken before treatment and 1, 2, 4, 8 and 12 weeks after treatment. In addition, a more detailed analysis of the effects of the treatments on the subgingival flora was carried out on 12 pockets in 12 patients. Tetracycline strips, metronidazole strips and root planing and metronidazole strips were more effective than chlorhexidine strips in causing reductions in total anaerobic count and anaerobe/aerobe ratio. However, the changes in microbial parameters rebounded to approach baseline levels 4 weeks after treatment. Chlorhexidine caused no detectable changes in the composition of the subgingival microflora, while metronidazole had a variable effect. Tetracycline appeared to effect major shifts in the composition of the microflora of treated pockets but caused a marked selection of tetracycline-resistant organisms.

Acrylic Resins↗

PubMed1991

Thyrotropin response to thyrotropin-releasing hormone in elderly patients with and without acute illness.

The response of thyrotropin (TSH) to thyrotropin-releasing hormone (TRH) was measured in 70 clinically euthyroid elderly patients who were acutely ill and in 70 age- and sex-matched euthyroid controls who were free of acute disease. The incremental TSH response (delta TSH) was often blunted (less than 2 mU/l) in both groups, though more often in those with acute illness (30%) than in those without (19%). However, in patients from both groups who had a blunted delta TSH, there was often a substantial proportional rise in TSH. A substantial proportional TSH rise may be useful in differentiating between genuine thyroid disease and euthyroid sick syndrome in elderly patients with a blunted delta TSH.

Acute Disease↗

PubMed1991

The effect of some chlorhexidine-containing mouthrinses on salivary bacterial counts.

A number of chlorhexidine mouthwashes are available commercially which differ in formulation and regimen of use. As a comparative measure of antimicrobial persistence, this study evaluated the effect of 4 chlorhexidine mouthwash formulations on salivary bacterial counts after a single rinse. The study was a randomised single-examiner blind 5-way crossover investigation employing a panel of 10 young healthy human volunteers. The 0.12% and 0.2% commercial formulations when rinsed according to the respective manufacturers instructions produced similar large and prolonged reductions in salivary bacterial counts during the 7-h period. A 0.1% formulation also commercially available produced minimal effects on salivary bacterial counts and was little different to the saline rinse. A reformulated 0.1% rinse, not commercially available at the time of the study, produced significant salivary bacterial count reductions over the 7-h period albeit to a lesser degree of magnitude than to the 0.2% and 0.12% rinses. The results were consistent with comparative plaque inhibitory studies of the formulations and suggest that the method is a quick and simple way of screening products for antimicrobial and antiplaque potential.

Adult↗