Scientific misconduct in a breast-cancer chemotherapy trial: response of University of the Witwatersrand.
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Antineoplastic Combined Chemotherapy Protocols↗
Biomedical subjects
P Cleaton-Jones
Publications and source records attributed to P Cleaton-Jones.
Surveillance of primary dentition caries in Germiston, South Africa, 1981-97.
OBJECTIVE: This 17-year-long study examined trends of dental caries rates in the primary dentition of 6843 preschool children in a South African city. METHODS: Calibrated dentists did repeated cross-sectional epidemiological surveys of dental caries in 2- to 5-year-old nursery school children using WHO diagnostic criteria between 1981 and 1997. RESULTS: Both the percentage of children with dmft>0 and mean dmft increased between 1981 and 1989 and have slowly declined ever since in the absence of organised prevention to produce a secular trend of decreasing caries rates. The dt/dmft percentage ranged between 60% and 100% except in 1991 when it dropped to 40% and the ft/dmft percentage component rose proportionally, probably due to an economic effect. CONCLUSIONS: The percentage of children with dmft>0 and mean dmft decreased over the study period at all ages, the reason for which is unknown but is speculated to be due to a change in mutans streptococci strains.
Black or African American↗
Oral health in Hlabisa, KwaZulu/Natal--a rural school and community based survey.
AIMS: To investigate rates of dental caries and periodontal disease, available dental services and resources and perceived needs in a rural South African community. DESIGN: A cross-sectional field study including situational analysis and focus group discussions. SETTING: KwaZulu/Natal, South Africa. PARTICIPANTS: A total of 520 children, adolescents and adults. METHODS: WHO caries scores and periodontal CPI score were determined through clinical examinations in five age groups, 5-6 years, 12 y, 15 y, 35-54 y, 55 y+. Focus groups included ten 15-year-old children and ten adults. RESULTS: Caries prevalences and (mean scores) were 5-6 y 64% (dmft 3.0), 12 y 24% (DMFT 0.4), 15 y 27% (DMFT 0.8), 35-54 69% (DFT 2.6) and 55 y+ 80% (DFT 2.7). Most caries was untreated and where present, treatment had been extraction. Dental caries rates were low and except for 5-6 y were within WHO targets for the year 2000. Periodontal disease prevalence was high but would respond to improved oral hygiene. Knowledge of oral health was rudimentary. CONCLUSIONS: A district-wide oral health promotion programme is required preceded by research to define effective health education messages. Access to simple but effective preventive and curative services would seem reasonable. In view of the lack of resources ART is suggested as caries treatment.
Adolescent↗
Nutritional status and dental caries in a large sample of 4- and 5-year-old South African children.
BACKGROUND: Evidence from studies involving small samples of children in Africa, India and South America suggests a higher dental caries rate in malnourished children. A comparison was done to evaluate wasting and stunting and their association with dental caries in four samples of South African children. DESIGN: Cross-sectional study based on random sampling of birth records of two age bands. METHODS: A total of 2,728 4- and 5-year-old South African children from one rural community and three urban communities were examined for nutritional status and dental caries. RESULTS: In the total sample prevalences of wasting were mild (28%), moderate (4%) and severe (2%). For stunting the prevalences were mild (13%), moderate (3%) and severe (1%). For both conditions rural children showed higher proportions than the other groups. Statistical analysis showed statistically significant differences for wasting and stunting between the study groups. No significant association was found between the prevalence of caries and stunting or wasting, but an association was noted between wasting and decayed, missing and filled (dmf) surfaces (P = 0.003). CONCLUSIONS: In the series of children studied, nutritional status was not found to be clinically relevant to dental caries prevalence and experience.
Child Nutrition Disorders↗
Dental caries trends in Africa.
OBJECTIVES: To determine trends in published dental caries rates in Africa. METHODS: A systematic review of published information 1967-1997 was done on-line with the key words dental caries and the name of each of the 35 countries in sub-Saharan mainland Africa. For inclusion in the analysis WHO methods had to have been used for 5- to 6-, 11- to 13-, 14- to 15- and 35- to 44-year-old indigenous Africans. RESULTS: Of 327 papers published in the study period 69 were proper epidemiological studies and 45 fulfilled inclusion criteria. The groupings of caries prevalence and severity were evaluated. In two, significant declines in caries severity were seen for 5- to 6- and 35- to 44-year-olds. Of the remaining eight groupings there were non-significant decreases in five and increases in three. CONCLUSIONS: The study showed a predominantly downward trend in dental caries which was statistically significant for DMFT at age 5 to 6 years and for DMFT at 35 to 44 years.
Adolescent↗
Relative displacement resistance of standard and low-profile bone plates in experimental mandibular angle fractures.
OBJECTIVE: The purpose of the study was to compare the resistance to displacement of low-profile and standard titanium bone plate with an experimental mandibular angle fracture model. STUDY DESIGN: A jig was used to produce standard horizontally and vertically unfavorable mandibular angle fractures in 24 healthy baboon hemimandibles. Each hemimandible was immobilized with either a standard or a low-profile titanium bone plate with a Champy unicortical technique. The resistance to displacement was measured in a tensile-testing machine, and results were analyzed with a three-way analysis of variance. RESULTS: Mean (SD) forces required to displace the fractures were standard plate 68.7 (22.8) kg and low-profile plate 46.5 (24.6) kg. CONCLUSIONS: The standard plates provided significantly more resistance to displacement, and 75% of the low-profile plates fractured through a screwhole.
Animals↗
A histological and quantitative histomorphometric study of apexification of nonvital permanent incisors of vervet monkeys after repeated root filling with a calcium hydroxide paste.
The purpose of this study was to compare the effect of a monthly refilling of the root canals with calcium hydroxide paste with a single packing or replacement of the paste at 3 months on the apexification of nonvital maxillary incisors of vervet monkeys. Forty-eight maxillary incisors from 12 monkeys were used following radiographic determination that root development was incomplete. The pulps were extirpated under general anesthesia and the root canals filed and cleaned. The root canals were filled with a commercial calcium hydroxide paste, Calxyl, and a temporary cavity filling placed. Twelve teeth were left without further treatment. The calcium hydroxide paste was replaced in 12 teeth after a 3-month interval, and in the remaining 24 teeth the calcium hydroxide root filling was replaced five times at monthly intervals. The monkeys were killed after 6 months, and blocks of the teeth and surrounding tissues were embedded, decalcified and 6 microns serial sections prepared and stained. The sections were studied histologically to evaluate 11 parameters. Significant differences were found in the amount of calcium hydroxide at the apices, the presence of new cementum on the roots and the degree of inflammation, all of which were better in the monthly refill group. Histomorphometric measurements to evaluate the obturation of the open apices and the volume of new primary osteocementum showed no significant difference between the three groups. It was suggested that after the initial root filling with calcium hydroxide there was nothing to be gained by repeated root filling either monthly or after 3 months, for at least 6 months.
Analysis of Variance↗
The plaque acidogenic response to carbohydrates of children from three ethnic groups in South Africa.
The plaque acidogenic response of children from three ethnic groups in South Africa to four different carbohydrates was investigated using the plaque sampling method. A total of 30, 12-year-old children, ten black, ten 'coloured' and ten white, completed this study. The foods tested were 10 per cent sucrose solution, maize porridge, strawberry flavoured yoghurt and banana. The blacks produced an intermediate plaque pH response to sucrose compared with the 'coloureds' and whites but the smallest response for the other carbohydrate challenges. It was concluded that a difference exists in the plaque acidogenic response to carbohydrate between the three ethnic groups and that this may in part account for differences in caries prevalences.
Acids↗
A comparison of three electrodes for the measurement of pH in small volumes.
An ion-sensitive field effect transistor (ISFET, Sentron, Sentron, Inc.) electrode was compared with a glass combination micro-electrode (MI-410, Micro-electrodes, Inc.) and a solid-state metal wire oxide pH sensor (Beetrode, World Precision Instruments, Inc.) with a liquid junction reference electrode (MERE1, World Precision Instruments, Inc.). The electrodes were assessed for linearity, reproducibility, accuracy, drift from the initial calibration between pH 4 and pH 7 and the time taken to record a stable reading. The ISFET was used to determine the pH in dental plaque samples (1 mg suspended in 20 microliters). The pH values correlated with the hydrogen ion concentration for all the electrodes (r = 0.98). The MI-410 fractured before this evaluation was completed. Coefficients of variation were 0.65% (pH 4) and 0.08% (pH 7) for the ISFET and 4.69% (pH 4) and 3.46% (pH 7) for the Beetrode. Both electrodes gave readings that differed significantly from the initial calibration, but the drift was greater for the Beetrode (F = 7.93; p = 0.0005) than the ISFET (F = 1.89; p = 0.1519). However, this drift was smaller than the change in pH as measured in dental plaque samples. The Beetrode gave a stable reading after 3.39 +/- 0.83 s and the ISFET after 2.2 +/- 0.76 s, while the MI-410 required at least 20 s. The ISFET type electrode is suitable for use in small volumes such as plaque suspensions, is easier to operate and yields results closer to the initial calibration than the Beetrode and is more robust than the MI-410 and the Beetrode.
Analysis of Variance↗
Tooth surface and pulp chamber temperatures developed during electrothermal bonding.
The rationale of electrothermal bonding is based on the premise that when an electric current is passed across the beaks of tweezers holding a stainless steel orthodontic bracket, heat will be generated by virtue of the electrical resistance of the steel bracket. This study was carried out to evaluate the temperatures generated on the tooth surface at the bracket/tooth interface and within the pulp chamber during electrothermal bonding. Temperatures were recorded with 5 and 7.5 A current levels applied as a 1 second pulse with time intervals between pulses of 1, 2, 3, and 4 seconds. The data showed that after three pulses with a 5 A current, the temperature on the tooth surface ranged between 43.3 degrees C (4 second intervals) to 53.6 degrees C (1 second intervals). By using a 7.5 A current, the temperature ranged from 77.5 degrees C (4 second intervals) to 85.9 degrees C (1 second intervals). The pulp chamber temperatures were evaluated in vitro for a mandibular incisor, the maxillary central and lateral incisors, a canine, a premolar, and a molar. The pulp chamber temperature of a mandibular incisor responded most, whereas that of premolars and molars responded least to temperature changes on the labial surface. The increase in mandibular incisor pulp chamber temperature after three pulses was 2.1 degrees C for 5 A and 2.8 degrees C for 7.5 A current while for a premolar the increase ranged from 0.9 degree C to 1.6 degrees C. On the basis of current evidence the increase in pulp chamber temperatures during electrothermal bonding may be considered to be clinically safe.
Bicuspid↗
Epidemiological profile of graduates of the Wits Dental Faculty 1927-1995.
The Wits dental school was first proposed in 1921 but had no premises until a private dental clinic was taken over in 1924 by the University, the same year that the Bachelor of Dental Surgery regulations were agreed to. In 1925 the first dental students registered and a year later, in 1926, the first seven lecturers in dental surgery were appointed. Since the first two graduates in 1927, 1916 dentists have graduated from the school as have 63 oral hygienists. Of the dentists 116 are female and 127 are black, Chinese, coloured or Indian. Regarding postgraduate qualifications, 346 have been awarded by the University on behalf of the dental school. This paper describes patterns in numbers of graduates, proportions registered in South Africa and contrasts registered South African dental school graduates with registered graduates from outside the country. It is clear that the Wits dental school has made a major contribution to South African society.
Dentists↗
Diseases and lesions associated with third molars. Review of 1001 cases.
This study reports on a retrospective survey of 1001 panoramic radiographs in a dental school population of persons with impacted third molars. The objective was to determine the association between pathologic conditions visible on radiographs and third molar teeth. In the series 2872 impacted third molars were examined. The most common problem seen radiolucencies. Other than caries, occurrence rates were low. Statistically significant differences in occurrences rates were seen within and between jaws for various pathologic conditions. The low rates did not offer support for the likely presence of pathologic conditions to be an indication for third molar removal.
Adolescent↗
Dental caries in Namibia--the first national survey.
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Adolescent↗
Variations in oral temperature.
This study investigated the temperature of healthy oral mucosa and underlying bone. Using a fine thermocouple and digital thermometer, four groups of temperatures were measured: (i) adjacent to unerupted third molars before and after surgical removal (n = 51); (ii) at the same site in patients not undergoing surgery (n = 30); and (iii) at the buccal incisor mucosa (n = 30). In each group sublingual temperatures were measured in order to calculate the temperature differential between measurement site and sublingual temperature to compensate for variations between sites and individuals. In the final group (iv) (n = 10) sublingual temperature was recorded in a closed mouth. Mean alveolar bone temperature was 5 degrees C cooler than overlying mucosa, and mean post-operative mucosal temperature was some 2.5 degrees C cooler than before operation (t = 2.32, P < 0.001). Sublingual temperature, in a closed mouth, remained relatively constant. In an open mouth, in both anterior and posterior regions, there were statistically significant decreases in sublingual temperature and in mucosal temperature differentials. Significant differences were also found between temperature differentials calculated using sublingual temperature measured at baseline and after 10 min. This indicates that sublingual temperature should be measured just prior to measuring a mucosal site.
Adolescent↗
Dental caries and social factors in 12-year-old South African children.
Dental caries prevalence (percentage caries-free) and experience (DMFS) were recorded, in 414 12-yr-old Indian and 401 white children living in adjacent urban communities with the same fluoride concentration in the drinking water (0.21-0.33 ppm) using WHO (11) criteria. Details of social factors: education level, family income, home space and occupants and parental occupation were obtained by questionnaire. Dental caries was significantly worse in the Indian children with regard to numbers caries-free (30%--white and 40%--Indian) and DMFS mean (sd) (3.65 (3.98) and 2.66 (3.49) working group, respectively). Social class, white or blue collar, family income and room to person ratio were significantly associated with dental caries in the white children but there were no significant associations in the Indian children. Multiple regression analysis showed race and sex to be significant factors.
Chi-Square Distribution↗
Salivary lactobacilli explain dental caries better than salivary mutants streptococci in 4-5-year-old children.
The present comparative study was undertaken to determine which of the bacteria, lactobacilli (lbc) and mutans streptococci (ms), in saliva better explains the variation of caries in 2728 South African 4-5-yr-old children. Caries was diagnosed according to WHO criteria. For lbc, the Dentocult system was used. The number of ms in stimulated saliva was counted on MSB agar plates. For correction of confounding factors, data on the frequency of intake of sweets were derived from extensive interviews. Oral hygiene was determined according to the simplified debris index of Greene & Vermillion. Simple correlation analyses between dmfs and bacterial counts were done for the total material and for three caries intervals by calculating Spearman's and Pearson's coefficients of correlation. Multivariate regression analyses were done on all intervals to correct for the confounding effects of regular intake of sweets, presence of salivary ms or lbc, and oral hygiene. Of the children, 68% had detectable lbc in the saliva, and 74% had ms. Except for children with more than 6 dmfs, the explanatory values, i.e., percentage of variation in dmfs explained, were higher for the lbc than for ms. Before correction, the values for the total material were 15 vs 6%; for children with caries, 7 vs 5%; for those with 1-6 dmfs, 5 vs 0.4%; and for those with more than 6 dmfs, 0.3 vs 2%. All r-values were reduced after correction, indicating that the confounders explain some of the correlation between dmfs and bacterial count.(ABSTRACT TRUNCATED AT 250 WORDS)
Child, Preschool↗
Associations of dental caries with salivary mutans streptococci and acid producing bacteria in 5-year-old children from KwaZulu and Namibia.
Two hundred and eighty-five, 5-year-old children from rural and urban KwaZulu and Namibia were examined for dental caries, salivary mutans streptococci and salivary acid producing bacteria. The findings showed statistically significant correlations between salivary mutans streptococci counts and ds and dmfs scores in all groups of children, the highest values being in Namibian children. Salivary acid forming bacteria had low correlations with few statistically significant groups. While salivary mutans streptococci counts may be a useful caries screening method in children of this age, salivary acid forming bacterial counts appear unsuitable.
Acids↗
Prevalence of dental caries in 4- to 5-year-old children partly explained by presence of salivary mutans streptococci.
The correlation between dental caries and the number of oral mutans group streptococci (ms) present has been shown to be weak. The aim of this investigation was to study associations between caries experience (decayed, missing, and filled surfaces [dmfs]) and the number of ms in stimulated saliva, with emphasis on the level of disease and the confounding effect of regular intake of sweets, the presence of salivary lactobacilli, and oral hygiene. In some 2,700 4- to 5-year-old South African children of different ethnic origins, caries was diagnosed on the basis of World Health Organization criteria and saliva samples were analyzed for ms after cultivation on mitis salivarius-bacitracin agar and for lactobacilli by using the Dentocult kit. Oral hygiene was scored on the basis of the Greene and Vermillion simplified debris index, while data on intake of sweets were derived from extensive interviews. Pearson's coefficient of correlation was computed, and multiple regression analysis was performed to correct for confounding factors. The distribution of the children in the eight caries classes was strongly associated with the ms class (P < 0.001), with those in the lower ms classes generally having low dmfs scores and those in the higher ms classes having dmfs scores distributed over the whole range. The r value for the two variables was 0.25 for the total material; this was reduced to 0.18 by correction for confounding factors. The corresponding values for children with caries were 0.21 and 0.17, for those in the 1 to 6 dmfs interval they were 0.07 and 0.03, and for those in the 7 to 81 dmfs interval they were 0.16 and 0.14. The data imply that the explanatory values for ms, those for the lower caries interval not counted, ranged from 6 to 2%. The unexpected results for children with caries might be due to their distribution pattern. It is concluded that there is a need for reevaluation of ms as a risk factor in dental caries.
Candy↗