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Biomedical subjects

F P Ashley

Publications and source records attributed to F P Ashley.

At least 19 recordsLinked to original sources
PubMed1994

Preliminary characterisation of antigens recognised by monoclonal antibodies raised to Porphyromonas gingivalis and by sera from patients with periodontitis.

A panel of 15 monoclonal antibodies (MAbs) was raised to Porphyromonas gingivalis and used to characterise the antigens which they recognise by ELISA, immunofluorescence (IF), Western blotting and patient serum inhibition studies. All the MAbs were specific for P. gingivalis and did not recognise 24 other species. Eight MAbs gave bright ring-like staining patterns against the majority of serotypes of P. gingivalis tested by IF. The antibodies could be grouped into 5 different antigen recognition profiles on Western blotting, and ELISA indicated that 8 of them bound to a capsular extract. Five antibodies bound to antigenic determinants recognised by sera from patients with periodonitis and 4 of these (1A1, 2B/H9, 3B1, 7D5) bound to a P. gingivalis 47kDa protease preparation on Western blotting. These antibodies are potentially useful for the purification and characterisation of biologically active components of P. gingivalis that are recognised by sera from patients with periodontitis.

Adult↗
PubMed1992

The relationship between 48-h dental plaque accumulation in young human adults and the concentrations of hypothiocyanite, 'free' and 'total' lysozyme, lactoferrin and secretory immunoglobulin A in saliva.

Samples of resting and stimulated whole saliva and stimulated parotid saliva were collected from 40 young adults. One week later, after 48 h on a standardized diet without oral hygiene, all available plaque was collected for dry weighing. An inverse relationship was found between the 'free' lysozyme concentration in stimulated parotid saliva and plaque dry weight (r = -0.46, p less than 0.01). There were no other statistically significant correlation coefficients between concentrations of individual salivary constituents and plaque dry weight. However, cluster analysis of constituents in resting whole saliva revealed three groups of subjects with different salivary profiles, and in particular with different concentrations of both IgA and hypothiocyanite. Subsequent analysis revealed differences in plaque dry weight between the groups, demonstrating the potential biological significance of cluster membership based on salivary factors.

Adult↗
PubMed1991

Relationship between calcium and inorganic phosphorus concentrations of both resting and stimulated saliva and dental plaque in children and young adults.

Calcium and inorganic phosphorus concentrations of both resting and paraffin-wax stimulated whole saliva and dental plaque were estimated in 39 young adults and 98 children aged 12-14 yr. Plaque was collected from the adults after 48 h without tooth-brushing and consumption of a standardized diet. Plaque was collected from the children without any dietary or oral hygiene restrictions. The results from the study with children provided consistent evidence for a statistically significant relationship between salivary and plaque concentrations of both calcium and inorganic phosphorus. However, multiple regression indicated that only the concentrations in the stimulated secretion were directly associated with concentrations in plaque. The apparent relationship between concentrations in resting saliva and plaque was due to correlation between resting and stimulated saliva. These relationships were less apparent in the young adults, in whom the controlled conditions resulted in a narrower range of mineral concentrations in dental plaque.

Adolescent↗
PubMed1991

Mouthbreathing, lip seal and upper lip coverage and their relationship with gingival inflammation in 11-14 year-old schoolchildren.

The gingival health of 201 schoolchildren aged 11-14 years was assessed at 6 sites on all the incisor and first molar teeth by recording separately the presence or absence of redness and bleeding on probing. Crowding of the incisor teeth was recorded as labio-lingual displacement and mesio-distal overlap. A 2nd examiner recorded the presence or absence of plaque at these sites and assessed mouthbreathing, lipseal and upper lip coverage of the maxillary incisors. Mouthbreathing, increased lip separation and decreased upper lip coverage at rest were all associated with higher levels of plaque and gingival inflammation. Multivariate analysis indicated that this association was statistically significant for mouthbreathing and lip coverage but increased lip separation was not independently related to plaque and gingivitis. The relationship of mouthbreathing and decreased upper lip coverage with gingivitis was most evident in the upper anterior segment and was still evident after covariate analysis to take account of variations due to gender, overcrowding and amount of plaque. However, allowance for these factors also suggested that the influence of mouthbreathing was restricted to palatal sites, whereas lip coverage influenced gingival inflammation at both palatal and labial sites.

Adolescent↗
PubMed1990

The relationship between the biochemical composition of dental plaque from both approximal and free smooth surfaces of teeth and subsequent 3-year caries increment in adolescents.

The biochemical composition of both types of plaque and the subsequent caries increment were investigated in 39 males aged 11-12 years at the time of plaque collection. The calcium concentration of free smooth-surface plaque was inversely related to both total and approximal 3-year DFS increment (p less than 0.01). A relationship between calcium concentrations in approximal plaque and subsequent caries was restricted to the 3-year increment on approximal surfaces (p less than 0.05). There was evidence for a direct relationship between caries increment and both magnesium and organic phosphorus concentrations in plaque on the free smooth surfaces only (p less than 0.05). In contrast, a direct relationship between total caries increment and both total and intracellular carbohydrate concentrations reached statistical significance for approximal plaque only (p less than 0.05). Regression analysis indicated that the combination of the calcium and inorganic phosphorus concentrations of free smooth-surface plaque and the intracellular carbohydrate concentrations of approximal plaque explained 40% of the variation in subsequent caries increment.

Adolescent↗
PubMed1990

Relationships between the biochemical composition of both free smooth surface and approximal plaque and salivary composition and a 24-hour retrospective dietary history of sugar intake in adolescents.

The relationships between the composition of both free smooth surface and approximal plaque and salivary composition and sugar intake assessed from a retrospective 24-hour dietary history were investigated. The inorganic phosphorus concentrations of both types of plaque collected from the permanent dentition were directly related to concentrations in stimulated whole saliva of 45 males aged 12-13 years. The calcium, inorganic phosphorus, water-soluble carbohydrate and protein concentrations of free smooth surface plaque were related to both the time since the last reported sugar intake and the amount of sugar and number of sugar intakes consumed in the previous 24 h as assessed from the retrospective diet histories of 75 females aged 14-15 years. A similar relationship with the reported time since sugar was observed for the calcium and carbohydrate concentrations in approximal plaque, but an association with the reported 24-hour sugar intake was not observed. Fewer statistically significant correlation coefficients were observed between the composition of both types of plaque and the reported sugar intake in the male subjects. The results indicate that the composition of both types of plaque are related to the composition of saliva and the time elapsed since the last sugar intake, but the relationship between the composition of plaque and sugar intake may differ between free smooth surface and approximal plaque.

Adolescent↗
PubMed1989

Identification of caries risk in schoolchildren: salivary buffering capacity and bacterial counts, sugar intake and caries experience as predictors of 2-year and 3-year caries increment.

Six variables which are capable of measurement at the chairside were assessed for their ability to identify children who would experience high caries increments during the subsequent 2 or 3-year period. The predictor variables measured in 84 urban schoolchildren, aged 11-12 years at baseline, were: baseline caries experience, salivary buffering power, counts of salivary Streptococcus mutans and lactobacilli, and two estimates of between-meal sugar intake. All the predictor variables showed statistically significant correlations with either 2-year or 3-year caries increment. Approximately 25% of subjects were identified as high risk individuals on the basis of a 2-year DFS increment of 5 and above, or a 3-year increment of 8 and above. None of the predictor variables achieved the target predictive value of 80%, either individually or in combination. The combination of Streptococcus mutans counts and buffering capacity measurements at baseline correctly identified low risk during the 3-year period in 78% of individuals (specificity), but only identified 12 out of 19 individuals (63%) at high risk (sensitivity), giving a predictive value of 75%. The predictive value for baseline caries experience was 66%. The results of the present study indicate that the salivary diagnostic tests have potential, but need further development before they can be used with confidence in clinical practice.

Buffers↗
PubMed1989

The occurrence of Actinobacillus actinomycetemcomitans, Bacteroides gingivalis, Bacteroides intermedius and spirochaetes in the subgingival microflora in relation to the early onset of periodontitis in a group of adolescents.

Subgingival samples were obtained from mesial and distal surfaces of first molars in 100 subjects aged 14 years at baseline. Sites were monitored at 6-monthly intervals for clinical loss of attachment. Six subjects showed greater than 1 mm loss of attachment at one site 18-24 months later. Further samples were obtained from these sites together with a comparison sample from the contralateral site and equivalent sites in a matched control subject. Actinobacillus actinomycetemcomitans was more frequently isolated from sites following loss of attachment, but it was also found in one comparison site and one control subject. Bacteroides gingivalis was found in only one subject at a site which subsequently experienced loss of attachment. A higher median proportion of spirochaetes was observed in sites after diagnosis of loss of attachment. The median proportion of Bacteroides intermedius was higher at both the baseline and 12-month examinations in subjects who subsequently lost attachment. Further work is required to substantiate the differences which preceded diagnosis of loss of attachment.

Actinobacillus↗
PubMed1988

Collection and biochemical analysis of human dental plaque from the approximal tooth surfaces and comparison with plaque from free smooth surfaces.

The composition of approximal plaque was compared with that normally collected from the free smooth surfaces in investigation of 45 males aged 11-14 years and 75 females aged 13 years. Statistically significant differences in calcium, inorganic and organic phosphorus, magnesium, fluoride and carbohydrate were observed between free smooth-surface and approximal plaque. The concentrations were always lower in the approximal sample, ranging from 55 to 70 per cent of those in free smooth-surface plaque. A subsequent comparison in 12 students indicated that the concentration of total lipids in approximal plaque was about twice that of free smooth-surface plaque, a difference which could explain the quantitative disparity in total composition between the two types of plaque in the studies with children. The differences are consistent with approximal plaque having reduced access to a range of environmental factors due to diffusion limitation in its deeper layers.

Adolescent↗
PubMed1988

Assessment of bone loss in periodontitis from panoramic radiographs.

Bone loss in chronic periodontitis was assessed from panoramic radiographs by direct measurement from the cemento-enamel junction (CEJ) and by measuring the proportion of the tooth length supported by bone. Mesial and distal bone levels of all available teeth were assessed for 50 patients aged 30-39 years referred for periodontal treatment. 85% and 74% of surfaces were measurable by the proportional and direct techniques, respectively. 27% of surfaces had no bone loss according to the proportional score, whereas 22% had a CEJ to alveolar bone distance of less than 2 mm. In addition, over half the surfaces with a proportional bone loss score of zero had a CEJ to alveolar bone distance of 2 mm or more, and for each proportional bone loss score, there was considerable overlap in the CEJ to alveolar bone distances recorded. The validity of the CEJ to alveolar bone measurements was established by comparison with direct measurements at periodontal surgery. The results support the use of direct measurement from the CEJ to alveolar bone rather than the assessment of the proportion of the tooth length within the bone when investigating bone loss from panoramic radiographs. This population of 30-40-year-old periodontal patients had a mean of 50% of sites with a CEJ to alveolar bone distance of 3 mm or more, and at such sites, there was a mean additional bone loss of 2.1 mm.

Adult↗
PubMed1988

The effects of experimental variations in dietary sugar intake and oral hygiene on the biochemical composition and pH of free smooth-surface and approximal plaque.

The biochemical compositions of free smooth-surface and approximal plaque were compared after 48 hours in the presence and absence of twice-daily toothbrushing and during ingestion of either high- or low-sugar diets in ten young adults. In addition, the effect of a single sugar intake on the pH of both types of plaque was investigated. The results confirmed previously reported differences in biochemical composition between free smooth-surface and approximal plaque, the concentrations of inorganic ions and carbohydrate fractions being generally lower in the approximal sample after all experimental regimens. The concentrations of calcium and phosphorus were doubled on the low-sugar diet compared with the high-sugar diet in both types of plaque. A significant decrease in carbohydrate concentrations was observed in free smooth-surface plaque in subjects on the low-sugar diet, but not in approximal plaque. Little variation was observed in the biochemical composition which could be attributed to the presence or absence of toothbrushing. The pH in free smooth-surface plaque was lower than that in approximal plaque five minutes after a sugar intake, but the situation was reversed two hours later. The results indicate that differences in composition and pH between free smooth-surface and approximal plaque are associated with reduced access to salivary and dietary influences due to diffusion limitation in the deeper layers of plaque.

Carbohydrates↗
PubMed1987

The effect on healing of the application of citric acid during replaced flap surgery.

The aim of this double-blind controlled clinical trial was to assess the effect on healing following conditioning the root surface with citric acid during replaced flap surgery. Healing was assessed in 18 pairs of sites in 12 patients before surgery and after 3 months; healing was also assessed in 13 pairs of these sites in 10 of the patients after 9 months. During surgery, the root surface at 1 site from each pair was treated with citric acid pH 0.6 for 3 min and the contralateral site was exposed to sterile saline. Healing was assessed by measuring attachment levels, probing depths and recession; in addition, gingival crevicular fluid flow was measured, as was the degree of bleeding on probing. The mean gain of attachment (mm) in the acid and control groups were 1.0 and 1.2, respectively, at 3 months and 1.1 and 0.9 respectively, at 9 months. The results of this study indicate, both clinically and statistically, that the difference in healing between the acid and the non-acid sites is not significant. Thus no additional benefit is shown by using citric acid in conjunction with replaced flap surgery on anterior teeth.

Adult↗
PubMed1986

Assessment of the WHO partial recording approach in identification of individuals highly susceptible to periodontitis.

The use of the WHO partial recording approach (CPITN) in the identification of 20-30-yr-old individuals with high past or present susceptibility to periodontitis was investigated in two studies in a factory population. Comparison with a traditional assessment in 149 subjects indicated that the probing depths and bleeding scores of the partial recording sites correlated well with the other sites which were less prone to periodontal disease than the CPITN sites, and that all the 23 subjects with deep pockets would have been identified by the use of the CPITN sites alone. However, when 75 of the subjects were re-examined using the partial recording sites, assessment of loss of clinical attachment levels indicated that only 16 of the 33 subjects who had loss of 2 mm or more clinical attachment at two or more sites had deep pockets, indicating that in this group assessment using pocket depth measurement alone seriously underestimated the proportion of individuals with a high past or present susceptibility to periodontitis.

Adult↗