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Biomedical subjects

P Cleaton-Jones

Publications and source records attributed to P Cleaton-Jones.

At least 19 recordsLinked to original sources
PubMed1992

Biocompatibility testing of a silicone maxillofacial prosthetic elastomer: soft tissue study in primates.

Little information exists on the biocompatibility of maxillofacial prosthetic materials. Cosmesil material is a purpose-designed facial prosthetic elastomer that has an established clinical profile in humans but results of biocompatibility testing have not been published. Cosmesil, acrylic resin (positive control), black surgical gutta-percha (negative control), and Silastic 382 material (Dow Corning, Midland, Mich.) (reference control) were processed as custom-designed implants. The implants were inserted into five chacma baboons for a 12-week period in intraosseous, subperiosteal, submucosal, and intramuscular sites. The histologic assessment was based on a modified form of the FDI-ISO Technical Report 7405 for subcutaneous implants. An evaluation was made of capsule formation and inflammatory response. The statistical analysis involved a three-way ANOVA and a Tukey-Kramer Student range test. The critical level of statistical significance chosen was p less than 0.05. The study found that gutta-percha provoked a statistically significantly thicker capsule and a severe inflammatory response. Acrylic resin, Cosmesil material, and Silastic 382 material produced capsule formations and an inflammatory response that did not differ significantly. Cosmesil material is not manufactured as an implant material, but from the present findings it is considered acceptably biocompatible for its intended use where there may be contact with internal tissue spaces that are contiguous to external surfaces.

Acrylic Resins↗
PubMed1991

Correlations between caries prevalence and potential etiologic factors in large samples of 4-5-yr-old children.

A data base containing information on dental caries, oral hygiene, gingival state, Streptococcus mutans and lactobacillus counts, and salivary flow rate and buffer capacity in some 2800 4-5-yr-old South African children was created in 1984. The children were equally distributed in four groups; rural black, urban black, urban Indian, and urban white. In this study, the data were used for simple linear correlations between all the factors including caries as well as stepwise multiple regression analyses between caries prevalence and the independent factors in each of the four groups. The highest r value obtained in the single correlations was 0.56 for dmfs/lactobacillus count in the white group. The overall pattern of the groups did not vary much. In the stepwise multiple regression analyses, lactobacilli entered first in all groups. S. mutans and oral hygiene interchanged as Nos. 2 and 3, and gingival state or buffer capacity came out as No. 4. The highest percentage of caries variability explained by these regressions was 25%, in the urban black group, while the lowest was 12%, in the indian group. It was concluded that our generally accepted etiologic factors are unsatisfactory to explain variation in caries in observational studies, which among other things might be ascribed to the inadequate way these factors generally are measured or estimated.

Black or African American↗
PubMed1991

Use of DI-S and CPITN as predictors in dental caries studies in the primary dentition.

The DI-S (simplified oral debris index), CPITN (Community Periodontal Index of Treatment Needs) and dmfs (dental caries experience in the primary dentition were recorded in 395 5-year-old black children living in rural and urban areas of Southern Africa. The DI-S and CPITN were grouped, independently and together, to examine their use as simple field methods of predicting dental caries. For each grouping the sensitivity, specificity and positive and negative predictor values were calculated. A CPITN grouping of 0 or of two or more sextants with bleeding, provided the most convenient specificity, sensitivity and predictor values. It is recommended that this simple method should now be used in prospective studies of caries activity.

Black or African American↗
PubMed1990

Pulp response to a composite resin inserted in deep cavities with and without a surface seal.

The objective of the present investigation was to observe pulp response to a composite material (Occlusin) placed in deep cavities with and without a zinc oxide-eugenol covering. Deep cavities were prepared in 116 teeth of four young baboons and divided into four groups. In group 1, Occlusin material was placed directly into the cavity, without etching, to approximately half the depth, cured, and covered to the surface with zinc oxide-eugenol. In group 2, the cavities were etched, a bonding agent was applied, and Occlusin material was used and cured in two increments to fill the cavities up to the surface. In group 3, the composite resin was placed in two increments as in group 2, but without etching and bonding; and in group 4 (control), the cavities were filled up to the surface with zinc oxide-eugenol. Follow-up times were 5, 30, and 90 days. Light microscopy revealed that, although some differences were observed, a good pulp response was evident in all groups.

Acid Etching, Dental↗
PubMed1990

Pulp revascularization in reimplanted immature monkey incisors--predictability and the effect of antibiotic systemic prophylaxis.

In 32 monkeys 105 immature maxillary incisors were extracted and reimplanted either immediately or after 30 or 60 min wet or dry storage. Of the monkeys, 17 (group I) did not receive and 15 (group II) received prophylactic treatment with 4 mg/kg doxycycline before extraction and 2 mg/kg for 5 d after reimplantation. The observation time varied from 6 to 8 weeks. After being histologically processed, the material was evaluated with respect to the amount of vital tissue and presence of micro-organisms in the pulpal lumen. A comparison revealed no difference in the results between the groups. The results were therefore pooled and statistically analysed with respect to the significance of apical foramen width, extra-alveolar time, wet or dry storage and presence of micro-organisms in the pulpal lumen for the occurrence of complete pulp revascularization (CPR). The overall frequency of CPR was 18%. Log-linear analyses (SAS, 1985) of the material as a whole or of separate parameters consistently revealed a relationship between presence of micro-organisms and absence of CPR (P = 0.0001). A higher frequency of CPR and a lower frequency of micro-organisms (P = 0.05) was found only for the group of immediately reimplanted teeth. The presence of micro-organisms could be explained for 61 teeth. In 27 of these, blood clots containing bacteria in the apical portion of pulpal lumen indicated contamination during the extra-alveolar time, while in 34, the micro-organisms originated from plaque covered mechanical damage in the cervical part of the root surface.

Animals↗
PubMed1990

Effect of topical application of doxycycline on pulp revascularization and periodontal healing in reimplanted monkey incisors.

Maxillary incisors in 47 monkeys, 54 in the experimental group (I) and 117 in the control group (II), were extracted and reimplanted, either immediately or after 30 or 60 min wet or dry storage. Incisors in the experimental group I were additionally kept 5 min in a suspension of 1 mg doxycycline in 20 ml physiologic saline, freshly prepared for each of the 15 animals before reimplantation. The observation time varied from 6 to 8 weeks. The teeth were removed in tissue blocks, histologically processed and evaluated for occurrence of complete pulp revascularization (CPR), presence of the micro-organisms in the pulpal lumen and ankylosis or inflammatory root resorption. Then the results were statistically evaluated, using log-linear analyses and chi-square tests (SAS, 1985) for the comparisons between group I and group II. These analyses revealed that topical application of doxycycline increased the frequency of complete pulp revascularization (P less than 0.002) and decreased the frequency of micro-organisms in the pulpal lumen (P less than 0.001). Furthermore, the frequencies of ankylosis (P less than 0.05) and inflammatory root resorption (P less than 0.001) were also decreased compared with the control group of teeth. It was concluded that the effect of topical treatment with doxycycline was most probably exerted on the micro-organisms that contaminated root surface during the extra-alveolar time; contamination of necrotic pulp tissue from the mechanical damage in the cervical part of the root surface was not affected.

Animals↗
PubMed1990

Comparison of three fluorosis indices in a Namibian community with twice optimum fluoride in the drinking water.

In Otjiwarongo, a town in Namibia with twice the optimum fluoride in the drinking water (1.56 ppm) the Dean (Dean, Arnold and Elvove, 1942), Thylstrup and Fejerskov (Thylstrup and Fejerskov, 1978) and TSIF (Horowitz et al, 1984) indices of fluorosis were compared in permanent teeth of the children aged 11 y living in the region. Fluorosis severety was skewed in all instances to lower scores within each index. With the Thylstrup and Fejerskov and TSIF indices it was possible to compare fluorosis by individual teeth; the former was significantly more sensitive in diagnosis (56 per cent vs 50 per cent prevalence). It is recommended that the aims of a fluorosis investigation be carefully detailed before selecting the fluorosis index to be used. If detailed information on individual teeth related to fluoride ingestion is needed the Thylstrup and Fejerskov index is recommended, especially in areas with raised fluoride intakes where it is anticipated that the fluorosis levels will be mainly in the low levels of severity.

Chi-Square Distribution↗
PubMed1990

Community Periodontal Index of Treatment Needs (CPITN) in KwaZulu and Namibia in 11-year-old children in 1988.

A sample of 603 11-year-old children from four low fluoride (less than 0.15 ppm) and one higher fluoride (1.56 ppm) communities in Namibia and KwaZulu were examined in 1988 using the CPITN. In a rural low fluoride community in Namibia only 6 per cent of children had healthy mouths compared with 42-58 per cent in the other communities. The main periodontal lesion seen was gingival bleeding (19-47 per cent) followed by calculus (6-47 per cent). There is a need for both oral hygiene improvement and simple intervention.

Child↗
PubMed1990

Social class, parents' education and dental caries in 3- to 5-year-old children.

The caries prevalence of 1273-, 4- and 5-y-old white children was determined with mirror and probe under natural light at mother and child clinics. The social class of the family, the educational level of the mother and that of the father were determined from a questionnaire filled in by the accompanying adult at the time of examination. Both social class and parent's education had a statistically significant influence on the caries prevalence: those in the lower social classes and with parents without tertiary education had a much higher prevalence of caries.

Child, Preschool↗
PubMed1990

Permanent dentition caries in KwaZulu and Namibia 11-year-olds.

The permanent dentitions of 11-year-old children in Namibia (n = 295) and KwaZulu (n = 308) living in rural and urban areas were examined using WHO caries diagnostic criteria. In low fluoride areas (less than 0.15 ppmF) significantly more caries was present in rural compared to urban KwaZulu but the prevalences in rural and urban Namibia were similar although significantly higher than in an area with 1.56ppmF in the drinking water. There was significantly more caries in rural Namibia than KwaZulu but the urban prevalences in both regions were similar. It is suggested that the urban findings are useful predictors for the needs of 11-year-old black children but local baseline surveys should be undertaken before considering dental programmes, treatment or preventive, for different rural communities in South Africa.

Child↗
PubMed1989

Dental caries at five and twelve years in a South African Indian community: a longitudinal study.

In 1979, 515 of 767 available Indian children born in Lenasia in 1974 were examined and their dental caries status was described. In 1986, 515 of the original 715 were re-examined in order to determine the pattern of dental caries in the primary and permanent dentitions of the same individuals. In contrast to studies in the literature in which treatment records have been used, both investigations were formal epidemiological field studies using calibrated examiners and WHO (1971) caries diagnostic criteria. A firm association was found between caries in the primary and permanent dentitions (r = 0.34).

Child↗
PubMed1989

Dental caries diagnosis calibration for clinical field surveys.

A method to calibrate examiners for field studies of dental caries was investigated. A total of 200 carious teeth were mounted in 40 plaster blocks so that 920 surfaces were available for examination with a curved probe, using WHO criteria. The results of two examinations of the teeth 1 week apart by 3 experienced and 4 new examiners and 1 year apart by two experienced examiners were compared. The intra-examiner and inter-examiner reproducibility was high for the experienced examiners; between experienced and new examiners the reproducibility fluctuated. Scanning electron microscopic examination of the tips of probes indicated that the sharpness was only slightly decreased within their usual frequency of use. The calibration system used is recommended for the training of examiners for dental caries field studies.

Adult↗
PubMed1989

Depth and area of dental erosions, and dental caries, in bulimic women.

Dental caries and the severity (depth) and area of erosions of tooth substance were studied in 11 bulimic subjects and 22 matched controls. Erosions were seen in 69% of the bulimics' teeth and in only 7% of the controls' (p less than 0.001). Depth of penetration was greater in the bulimics, extending even into the pulp, and the area of erosion was also larger. Scores for dental caries were higher in bulimics (mean DMFS 27.9, median 36) than in controls (mean DMFS 19.1, median 13.5), although the difference was not statistically significant. This study suggests that when erosions are present on the lingual surfaces of maxillary anterior teeth, as well as on the buccal surfaces of maxillary canines, premolars, and maxillary incisors, a diagnosis of bulimia is likely. Patients with these signs should be referred for medical help.

Adult↗
PubMed1988

Caries prevalence and severity in the primary dentition and Streptococcus mutans levels in the saliva of preschoolchildren in South Africa.

The caries prevalence (dmft) and severity (css) in 3-, 4-, and 5-yr-old children in South Africa were examined. Four levels of S. mutans in the saliva of 228 of these children was estimated by the spatula method. In all three age groups a statistically higher dmft and css was found with a S. mutans level of greater than 10(6) CFU/ml in saliva than at lower concentrations. At age 5 ANOVA showed significant differences between dmft and css at all S. mutans levels. A high concentration of S. mutans in the saliva may be an indicator of the high risk child at an early age.

Child, Preschool↗
PubMed1988

Cariogenicity of traditional African foodstuffs (maize, beans, sorghum, brown bread) on rat caries.

The cariogenicity of the following traditional African foods was tested in a rat model system: cooked maize and beans, cooked maize and spinach, uncooked and cooked sorghum, both plus 20% sucrose and brown bread, as well as a control (wheat starch plus 50% sucrose). Plaque extent was low in all the test groups and caries incidence was almost zero in all groups except for the cooked wheat starch and 50% sucrose group. Comparison to earlier results suggests a possible cariostatic effect of sorghum but not for the other traditional foods.

Animals↗
PubMed1987

Head holder for panoramic dental radiography.

A radiolucent head holder for the Pancentric Panorex dental x-ray machine is constructed and evaluated. Features include a wooden pointer to orient the head in the midsagittal plane, movable components adjustable into a number of fixed positions and a spirit level on an ear rod fitting.

Equipment Design↗