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Biomedical subjects

P E Cleaton-Jones

Publications and source records attributed to P E Cleaton-Jones.

At least 19 recordsLinked to original sources
PubMed2003

Mutans streptococci strains prevalence before and after cavity preparation during Atraumatic Restorative Treatment.

Critics argue that all carious dentine is not removed from the hand-prepared cavity during the Atraumatic Restorative Treatment (ART) procedure, and that the caries process is soon resumed. The aim of this study was to determine the effectiveness of ART in removing carious tissue, by investigating the numbers of mutans streptococci and lactobacilli, with emphasis on the prevalence of Streptococcus mutans and Streptococcus sobrinus strains before, and after ART treatment of dental caries. Two microbiology samples were collected. The first sample was removed from the centre of the carious lesion at the enamel-dentine junction, and the second was collected from the centre of the hard cavity wall above the pulp, after the soft infected dentine had been manually removed. A total of 71 mutans streptococci isolates from 31 children and 40 carious teeth were subcultured, biochemically characterised and genotyped by the arbitrarily primed polymerase chain reaction (AP-PCR). Results showed a significant decrease in TVC (P<0.0001), mutans streptococci (P < 0.0001) and lactobacilli (P = 0.0002) after cavity preparation. AP-PCR identified S. mutans strains that were undetectable during biotyping, and divided clinical isolates into two main clusters. In all, 63% (45/71) of isolates from the carious lesions comprised S. mutans strains. After cavity preparation, this was reduced to 35% (25/71), of which 30% (21/71) were S. mutans and the remaining 6% (4/71) S. sobrinus strains. The number of mutans streptococci strains was below detectable levels in 19 of the prepared cavities. The significant decrease in bacteria after manual cavity preparation demonstrates the reliability of a standardized ART technique, yet the presence of S. mutans strains shows that the effectiveness of the ART procedure can vary during treatment and between dental practitioners.

Child↗
PubMed2003

Clinical, histological and microbiological study of hand-excavated carious dentine in extracted permanent teeth.

Changes in cultivable flora in dentine samples collected before and after hand excavation were examined in association with clinical status of the cavity surface, light microscopy and scanning electron microscopy (SEM). Thirty-five extracted permanent molar teeth with an occlusal caries lesion were excavated with hand instruments according to the atraumatic restorative treatment (ART) approach. Excavation pressure, dentine colour and consistency were recorded at the dentine-enamel junction (DEJ) prior to carious dentine removal and at the cavity floor after the final excavation; a microbiological sample of dentine was taken at both stages. Twelve restored teeth; six with positive and six with negative bacterial growth on the second sample, were selected for light microscopy and SEM. The hand-excavation removed tooth structure was soft, irreversibly damaged, dark and highly infected. Hand excavation reached dentine of increased hardness with a more normal colour to provide a sound structural base for restoration. Light and SEM examination of the cavity floor showed infected dentinal tubules in all 12 teeth examined. Linear logistic analysis showed a statistical association between light-yellow dentine on the cavity floor and an absence of bacterial growth (P = 0.006). This short-term in vitro study showed that caries-producing bacteria remained in dentine close to the cavity floor in 26/35 teeth despite clinical observations that indicated a suitably prepared cavity floor.

Bacteria↗
PubMed2002

Accurate diagnosis of occlusal carious lesions--a stereo microscope evaluation of clinical diagnosis.

This study was undertaken to validate the caries status of 214 teeth by serial sectioning and microscopy after caries diagnosis using four methods. Two hundred and fourteen extracted human teeth with varying degrees of caries were mounted in the jaws of nine training manikins. All tooth surfaces were examined and recorded for caries by four dentists using bitewing radiographs, fibre-optic transillumination (FOTI), mirror alone and a mirror and sharp probe on two separate occasions. Thereafter the teeth were serially sectioned and assessed microscopically for depth of caries lesion on a graded score of 0-7. This report assessed the diagnostic outcome of 2,183 observations for occlusal surfaces. Sound diagnoses predominated over unsound until caries was present in the inner half of dentine. Specificity was between 90% and 95% and sensitivity 26% and 50% depending on which diagnostic method was used and where the sound/unsound threshold was set. Negative and positive predictive values were similarly influenced and varied between 53% and 80% and 73% and 90%, respectively. Probit analysis showed no significant differences (P < 0.05) between examiners and diagnostic methods. Diagnosis of occlusal caries undertaken in an in vitro simulated clinical situation is inaccurate until the caries lesion extends deep into the dentine no matter which of the four methods was used.

Chi-Square Distribution↗
PubMed2002

Airway status in civilian maxillofacial gunshot injuries in Johannesburg, South Africa.

BACKGROUND: Airway management of the maxillofacial gunshot injury constitutes a critical decision and an area that requires review in the context of civilian injuries. Most of our knowledge is extrapolated from military experience, which constitutes a different trauma patient group. This paper reports a retrospective survey of airway status in relation to maxillofacial gunshot injuries. The objective is to correlate clinical findings with treatment decisions. METHODS: A survey was done of 11,622 archived maxillofacial surgery records (1987-1992) in the three academic hospitals in Johannesburg. RESULTS: There were 211 maxillofacial gunshot injuries, for which 92 patient records had sufficient detail for inclusion in the analysis. The typical patient was a black male aged 20-29 years, shot with a low-velocity bullet of 0.38 calibre, admitted to hospital the day of the injury, operated on within 4 days, and discharged 4 days later. The airway was threatened in 20/92 cases at admission; 12/20 cases were treated with oro-or nasotracheal intubation, and 9/12 later had elective tracheostomies; 8/20 needed immediate surgical airways, 5 tracheostomies and 3 cricothyroldotomies (all later converted to tracheostomies). Three of thirty-seven patients with normal airways on admission later required emergency tracheostomy. CONCLUSIONS: An abnormal airway was significantly more likely after a high-velocity injury, and when the tongue, floor of mouth, midline or bilateral facial skeletal bones were involved.

Adult↗
PubMed2001

Surface roughness of aesthetic restorative materials: an in vitro comparison.

The purpose of this study was to compare the surface roughness of three types of aesthetic restorative material. Six standard samples of two brands of each type of material were prepared namely: hybrid composites (Prodigy, Z100), compomers (Compoglass F, Hytac Aplitip) and glass ionomer cements (Photac-Fil, Vitremer) in a perspex mould (N = 36). Upper and lower surfaces were covered with Mylar strips which, in turn, were covered with glass slides and compressed to express excess material. After light curing, specimens were stored in distilled water for 14 days. Thereafter, one side of each specimen was polished sequentially with medium, fine and super fine Soflex discs (treatment). Untreated surfaces served as controls. All surfaces were examined with Talysurf and the surface roughness (Ra) of each specimen was recorded. Three measurements were made of each specimen. A 4-way ANOVA and Tukey's Studentised range test were used to analyse the data. Statistically significant effects were found for both type of material (P = 0.0001) and for treatment process (P = 0.0065). Among unpolished specimens: Compoglass F is significantly rougher than Vitremer, Z100, Prodigy and Hytac Aplitip, and compomers are significantly rougher than hybrids. Among polished specimens: Photac-Fil is significantly rougher than Z100 but does not differ from Compoglass F, Vitremer, Prodigy and Hytac Aplitip, and glass ionomers are also significantly rougher than hybrids. The smoothest surface is obtained when curing materials against a Mylar strip.

Analysis of Variance↗
PubMed2000

Energy and macronutrient intake in relation to dental caries incidence in urban black South African preschool children in 1991 and 1995: the Birth-to-Ten study.

OBJECTIVE: To study energy and macronutrient intake in relation to dental caries incidence among urban black South African children at the ages of 1 and 5 years. DESIGN AND SUBJECTS: Food frequency questionnaires and WHO caries diagnostic criteria were used. The study sample of 1639 urban black children with nutrition and dental information from the 1991 and/or 1995 Birth-to-Ten (BTT) Study interceptions comprised true longitudinal (n = 259) and cross-sectional (n = 1216 for 1991 and n = 164 for 1995) subjects. For the longitudinal group true dmfs (decayed, missing, filled surfaces) incidence and average intakes of energy and macronutrients between 1991 and 1995 were calculated. SETTING: South Africa. RESULTS: Median macronutrient intakes were not significantly different between the cross-sectional and longitudinal samples. Dental caries prevalences at age 1 were 1.2% and 1.5% for the cross-sectional and longitudinal samples, respectively. By age 5 these values were 60.4% and 62.2%, respectively. The median dmfs score at age 1 was 0. At 5 years this was 2 for all children and 5 for those with caries. Statistical analysis for trend at age 5 showed a significant increase in caries prevalence with increasing energy, carbohydrate and added sugar in the cross-sectional sample only. The only significant changes in dmfs scores were seen for energy and added sugar for the whole sample. The r values between log(dmfs incidence + 0.3) and the average nutrient log variables were low, and a general linear models analysis showed no statistically significant effects on log(dmfs incidence + 0.3) of any of the log nutrient variables. CONCLUSIONS: For the relationship between macronutrient intake and caries (prevalence and incidence), a cross-sectional and true longitudinal study gave similar results.

Black or African American↗
PubMed2000

Temperatures in and around mandibular fractures.

This study measured the temperature in and around mandibular fractures in 20 anaesthetized patients. A fine calibrated thermocouple attached to a digital thermometer was used to measure temperature at the bone surface margin of a mandibular fracture and 5 and 10 mm from the fracture; within the fracture against the bone at 5, 7 and 10 mm depths and at the base of 7 mm deep biopsy cavities 5 and 10 mm distant from the fracture line immediately after biopsy, then 1 and 2 min later. On the surface the temperature was approximately 1 degrees C warmer than at the 5 and 10 mm sites distant from the fracture. Temperature reduced at the 1 and 2 min readings after the biopsy cavity cutting. This study confirmed that the surface temperature is lower than internal bone temperatures.

Adult↗
PubMed1999

Long-term histologic changes in the dental pulp after posterior segmental osteotomies.

OBJECTIVE: The purpose of this study was to examine pulp tissue for 18 months after segmental osteotomy in nonhuman primates. STUDY DESIGN: In this long-term experimental study, subapical, posterior, maxillary, and mandibular osteotomies were done in 26 baboons (Papio ursinus). Baboons were killed humanely immediately after operation and at 3, 6, 12, and 18 months, when tissues were perfusion-fixed. Longitudinal step-serial sections of dental pulps were examined. RESULTS: There was a loss of the odontoblast layer as early as 3 months after surgery. Inflammatory cell infiltrate was most marked in the early postoperative stages, and the formation of osteodentin and secondary dentin was evident after 6 months. Foci of necrosis were present in the 3-month and 6-month groups but were replaced by pulp fibrosis in the 12-month and 18-month groups. All these changes were more frequent in experimental than control teeth. CONCLUSIONS: The histologic changes seen should not affect the prognosis of teeth in subapical osteotomy segments if clinicians are careful not to damage root apices and do regular, careful, clinical, and radiographic follow-up examinations. Because many pulps healed spontaneously in the study teeth, endodontic treatment should be delayed until it is clearly needed.

Animals↗
PubMed1999

Mutans streptococci and other caries-associated acidogenic bacteria in five-year-old children in South Africa.

Correlations between mutans streptococci and caries are inconsistent; some studies show that early caries may occur with other bacterial species possessing the ability to survive, interact and compete with mutans streptococci. This study looked at the relationship between mutans streptococci, Lactobacillus, Actinomyces and Veillonella in saliva and plaque collected from four tooth sites in two ethnic groups, with and without caries. All samples were collected and cultured onto selective media. Colonies were enumerated and identified using biochemical tests. Pearson correlations showed low yet statistically significant correlations between plaque mutans streptococci counts and the number of decayed surfaces (ds) and decayed, missing and filled surfaces (dmfs) of primary teeth in blacks and in coloreds (historical race classification). Salivary mutans streptococci counts correlated with ds and dmfs in coloreds. No relationship was found between ds, dmfs and Lactobacillus, Actinomyces or Veillonella numbers. Significant associations were evident between plaque mutans streptococci and Veillonella and Lactobacillus in black children with caries and between plaque mutans streptococci and Actinomyces and Lactobacillus and Veillonella in colored children. Hence, oral microbes are in constant flux but have interrelationships in children with caries.

Actinomyces↗
PubMed1999

Small tidal volume ventilation using a zero deadspace tracheal tube.

The zero deadspace tracheal tube (ZEDS-TT) is a double-lumen endobronchial tube with a truncated bronchial limb. Functionally it is unrelated to the familiar endobronchial tube used in lung isolation surgery. It is placed in the same position as a regular tracheal tube and, by means of special connectors, one limb is used for inspiration and the other for expiration, thereby greatly reducing anatomical and apparatus deadspace. In this study, we have compared respiratory and ventilatory effects of reduction of tidal volume (VT) via a single-lumen tracheal tube and the ZEDS-TT during controlled ventilation with a Siemens Elema 900C Servo ventilator. Eleven consenting adult patients (ASA I and II) undergoing elective peripheral surgery were studied. Starting at a VT value of 10 ml kg-1, data were recorded for each tube type. VT was reduced by 2.5 ml kg-1 every 10 min and stabilized data recorded. Minute volume was kept constant by increasing ventilatory frequency at each reduction in VT. We found that the ZEDS-TT produced a significant reduction in PaCO2 and airway pressure for any VT used, while maintaining oxygenation.

Adult↗
PubMed1999

Trauma to primary teeth of South African pre-school children.

A clinical survey of 1466 children of typical South African communities showed a prevalence rate of primary tooth trauma of 15%. Trauma was least common at age 1-2 years (10.7%) and most common at 4-5 years (20.6%). The commonest trauma seen was fracture of enamel only (71.8%) followed by fracture of dentine (11.2%), tooth loss (8.2%) and discolouration without other sign of injury (5.6%).

Age Distribution↗
PubMed1999

Assessment of periodontal status and treatment needs of a disabled population using the CPITN.

The Community Periodontal Index of Treatment Needs (CPITN) was used to assess the periodontal status of 213 handicapped persons attending seven institutions in Johannesburg. Fewer than 2% had healthy mouths, 8% had bleeding only, followed by calculus (46%), shallow pockets (40%) and deep pockets (4%). The mean number of sextants with bleeding or higher score was 5.9. Oral hygiene instruction was indicated for 98% and prophylaxis for 90% of the participants. The CPITN was easily used in the disabled population but may overestimate treatment need in view of the current understanding that periodontal disease does not automatically progress from a low CPITN level to the next. A more appropriate measure of treatment need in handicapped persons is required.

Adolescent↗
PubMed1998

Vascularity of the dental pulp after segmental osteotomy in the chacma baboon (Papio ursinus).

OBJECTIVE: To assess the vascularity of the dental pulp after segmental operations with and without interpositional autogenous bone grafting. DESIGN: Experimental study. SETTING: University Department, South Africa. ANIMALS: 26 chacma baboons. INTERVENTIONS: Maxillary and mandibular posterior segmental osteotomies were perfused with barium sulphate 3, 6, 12 and 18 months postoperatively. The animals were killed at 3, 6, 12 and 18 months after surgery and perfused with barium sulphate. Barium-filled vessels were counted in histological sections from 189 control and experimental teeth. MAIN OUTCOME MEASURE: Number of blood vessels. RESULTS: Blood vessel counts in mandibular teeth in osteotomy segments ranged from 0 to 1.15 compared with 2.27 to 4.58 in control teeth, while in maxillary teeth counts ranged from 0.54 to 2.22 for experimental teeth and 3.3 to 4.65 for controls. For both jaws, the numbers of vessels in experimental teeth gradually increased between 3 and 18 months but remained less than those in control teeth. Numbers of blood vessels were similar in graft and no-graft groups but both were less than half the counts in control teeth. CONCLUSION: Blood flow is present in the teeth at all times after posterior segmental osteotomy but there is a risk of ischaemia.

Animals↗
PubMed1998

Energy, macro- and micronutrient intake of 5-year-old urban black South African children in 1984 and 1995.

Food habits change over time. This paper reports results of nutritional studies among 5-year-old urban black children in 1984 and 1995 in the Johannesburg/Soweto area. The objective was to compare energy, macro- and micronutrient intake of 5-year-old urban black South African children. Dietary intake was assessed by detailed dietary histories in 1984 and food frequency questionnaires in 1995, conducted by trained interviewers. The intake of energy, macro- and most micronutrients was higher in 1995 than in 1984, except for vitamin A, ascorbic acid, copper and iron. Fat intake increased from 52 g/day in 1984 to 95 g/day in 1995. Only biotin and vitamin D fell below 67% of the recommended dietary allowances (RDA) for 4- to 6-year-olds, but mean intakes concealed the high percentage of children that had intakes below the RDA in 1984 and 1995. Urban black 5-year-old South African children consumed a low-fat (30% of total energy), high-carbohydrate (61% of total energy) diet in 1984, but a typical westernised diet by 1995 (fat 41% and carbohydrate 52% of total energy). With these changes, current reliable nutrition information is needed to assess the existing and future health needs of all South Africans.

Child↗
PubMed1998

Electrothermal bonding: shear bond strength of orthodontic brackets after two weeks.

Electrothermal bonding is based on acceleration of the setting reaction of a bonding: resin by the selective application of heat to the orthodontic bracket through the passage of a low voltage electric current. The purpose of this study was to compare the shear bond strength of nine resins comprising chemically-cured, light-cured, and glass ionomer types, 14 days after electrothermal and conventional bonding. Mean shear and bond strengths ranged from a low of 7.4 MPa for Sequence (electrothermally bonded) to a high of 15.4 MPa Concise (control). There was no statistically significant difference between the electrothermal and conventional bonding methods. All the resins produced bond strengths adequate for clinical orthodontics at 14 days.

Bisphenol A-Glycidyl Methacrylate↗
PubMed1998

Dental caries in African preschool children: social factors as disease markers.

OBJECTIVE: This study investigated the associations between dental caries prevalence and severity and social factors in 3- to 5-year-old African children. METHODS: Dental caries was diagnosed in natural light using WHO criteria, minors, and explorers. Socioeconomic information was obtained by questionnaire. RESULTS: The percentages of 3-, 4-, and 5-year-olds with any caries experience were 47 percent, 58 percent, and 63 percent, respectively. Mean dmfs scores (SD) were 2.2(3.6), 3.0(3.8), and 3.7(4.1), respectively. Family education was associated with caries prevalence (P = .03) and severity (P = .008) in a multivariable regression model. CONCLUSION: In the indigenous African group studied, family education is a disease marker to target in future caries risk evaluations.

Child, Preschool↗
PubMed1998

Transcutaneous electrical nerve stimulation in the treatment of myofascial pain dysfunction.

The effect of transcutaneous electrical nerve stimulation (TENS) plus conservative therapy (ibuprofen, bite plate, self-physiotherapy) on myofascial pain dysfunction (MPD) was determined. A single-blind trial as done in 10 patients with MPD with subthreshold TENS (frequency 35 Hz, pulse width 100 milliseconds, modulation 50%) compared with sham TENS at 8 visits over 14 weeks. Pain was assessed on a visual analogue scale before and after TENS at each visit and the data were analysed with the analysis of variance (ANOVA) for repeated measures. A highly significant effect was seen for time (F = 4.80, P = 0.0003) but not for TENS. Subthreshold TENS did not increase the symptom relief produced by conservative treatment with the protocol used.

Analysis of Variance↗