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Biomedical subjects

P M Cahen

Publications and source records attributed to P M Cahen.

At least 19 recordsLinked to original sources
PubMed1999

Use of the generalised linear model with Poisson distribution to compare caries indices.

In dental epidemiological studies, an analysis of variance assuming a normal distribution is commonly used to compare caries indices, which are often not normally distributed. As these indices represent discontinuous data, it would be preferable to use the negative binomial or the Poisson distribution. In this study, in order to compare the DMFS indices of adults working in the confectionery manufacturing industry in France, the results of the generalised linear model obtained using the normal and the Poisson distribution with identity or log built-in link function were compared. The negative binomial distribution was not used because it is very often unavailable in the most used statistical software. Analysis of the caries indices showed that the use of the normal distribution could lead to an incorrect interpretation of the data. Therefore it is concluded that the generalised linear model with Poisson distribution and over dispersion is to be preferred when comparing caries levels.

Adult↗
PubMed1996

Caries prevalence and salt fluoridation among 9-year-old schoolchildren in Strasbourg, France.

The 9-year-old group (236 children) of an epidemiological study carried out in 1991 in Strasbourg on children aged 6 to 15 years was selected with the aim of determining if the caries prevalence reduction observed could be related to the use of salt fluoridation (FS) introduced in France in 1987. From these 236 children, 143 answered a questionnaire which showed that 36 of them were fluoridated salt users and 107 were not. The dft index was significantly lower in the FS consumers which showed 35.5% dft reduction compared to the non-FS-consuming children. When using the Generalized Linear Model, this reduction was significant (P = 0.03). Although lower in the FS group, the DMFT and DMFS indices showed no statistical significant difference. It appeared that 72.2% of the users took simultaneously fluoride tablets but no dental fluorosis was observed. The use of fluoride tablets had a significant effect on the DMFS (P = 10(-2)). The children who consumed FS used more frequently fluoridated mouthrinses (P = 10(-3)) and had more frequent professional application of fluoridated gel and varnishes than non-consumers (P = 0.02). The DMFS index increased with the number of meals (P = 10(-6)), which was the most significant variable entered into the Generalized Linear Model. The children who brushed their teeth once a day had a DMFS value 2.6 times higher than those who brushed regularly three times a day (P = 10(-3)). The DMFS value was 4.4 times higher among the children who brushed their teeth irregularly when compared with those who brushed three times a day (P = 10(-2)).

Cariostatic Agents↗
PubMed1993

Caries prevalence in 6- to 15-year-old French children based on the 1987 and 1991 national surveys.

The caries prevalence in a multi-stage probability sample of 18,786 children representative of all French children 6-15 years of age was studied in 1991 and compared with the results of a similar survey made in 1987. A significant decline in dental caries in France became evident. This decline, observed in primary as well as in permanent teeth, was of variable magnitude among the different age groups. At the age of 6, 48.6% of the children were totally caries-free in 1991. At the age of 12, the DMFT and DMFS indices were 2.59 and 4.72, respectively, representing a corresponding decrease of 38% and 37%. In 1991, more caries-affected teeth or surfaces were filled, whereas fewer caries-affected teeth or surfaces were untreated. Females and children living in rural areas had a higher caries prevalence in both surveys. Pit-and-fissure lesions were the predominant caries types. Dental fluorosis was very uncommon; 96.1% of the 18,786 children examined in 1991 were totally free of any such lesions. Average plaque and calculus indices were similar in 1987 and in 1991, but a decrease of 25% was observed in the average gingival indices. Although the relative contributions of various preventive factors leading to this caries reduction are not clear, it should be noted that use of fluoridated salt (250 mg/kg KF) started in January, 1987. The sale of fluoridated dentifrices and the use of fluoride tablets and sugar substitutes increased during the period from 1987 to 1991.

Adolescent↗
PubMed1992

Urinary fluoride excretion in children using potassium fluoride containing salt or sodium fluoride supplements.

With the introduction of fluoridated domestic salt in France in 1986, questions have arisen with respect to its efficacy in caries prevention. It has been of interest to compare the urinary excretion of fluoride in children who consume fluoridated salt to that in children who take fluoride tablets. Ninety-three schoolchildren, 10-14 years of age, participated in the study and were divided into four groups: group I consumed fluoridated salt with every meal; group II ate at a school restaurant once a day and consequently consumed fluoridated salt at only their evening meal, as fluoridated salt is not authorized for use in collective restaurants; group III consisted of children taking fluoride tablets (1.0 mg F/day) exclusively, and group IV did not receive any systemic administration of fluoride for prevention and constituted a low-fluoride control group. Total 24-hour urine samples were collected from all subjects. The average daily urinary flow rates varied from 0.51 to 0.68 ml/min, but showed no statistically significant differences among the groups. The average urinary fluoride concentrations were 0.60, 0.30, 0.99, and 0.28 mg/l, respectively, for groups I-IV. The mean 24-hour urinary fluoride concentrations and excretion rates for children who consumed fluoridated salt at all meals (group I) were not statistically different from those using tables (group III). There were also no statistically significant differences between groups II and IV. The differences between urinary fluoride concentrations and excretion rates of groups I and III, as compared with group IV, were statistically significant.

Administration, Oral↗
PubMed1991

Effects of complete denture wearing on temporomandibular joints: a histomorphometric study.

At autopsy, 54 human temporomandibular joints were distributed in three groups. The first group was made up of 14 joints of dentate subjects (mean age = 51 years). The second group was composed of 12 temporomandibular joints of totally edentulous patients who had lost their teeth for at least 10 years (mean age = 82 years). The third group was composed of 28 joints of edentulous patients who had been wearing complete dentures for at least 20 years (mean age = 66 years). Sagittal serial decalcified sections were studied by light microscopy and was submitted to histomorphometry. Group 1 was characterized by a deep mandibular fossa with well-marked cortical layers of the temporal bones and the condyles. The fibrocartilages were multilayered and the articular disks had biconcave outlines. In group 2 a flattening of the mandibular fossa was observed, with a thinning of the cortical and spongy bones. The fibrocartilages were thin and not multilayered. In group 3, the structure of joints was similar to that of group 1. The mean values of the surfaces, thicknesses, and lengths of the measured parameters were systematically highest in group 1, whereas these mean values in group 3 were similar to or had a tendency to be close to the means of group 1. In contrast, the mean values of group 2 were always the lowest. It can be concluded that complete dentures had a favorable protective effect on temporomandibular joint structures.

Adult↗
PubMed1990

[Preventive dentistry in France].

In France, oral prevention has recently progressed in various aspects of dental caries prophylaxis which is reviewed in this paper. A better knowledge of dental caries prevalence has been obtained at a national level and the French Government authorized in October 1985 salt fluoridation for a period of 5 years which in addition to other means of caries prevention such as fluoridated toothpastes and various local and topical procedures has increased the potentials of fluoride use in France. In addition a larger use of fissure sealants has been encouraged. It is hoped that the introduction of salt fluoridation in France will reduce the caries incidence to a DMFT not more than 3 for the 12 year old children thus fulfilling the WHO goals for oral health in the year 2000.

Adolescent↗
PubMed1989

Periodontal treatment needs in populations of high- and low-fluoride areas of Morocco.

The purpose of this study was to determine the periodontal status and treatment needs, using the CPITN index, in a population aged 7 to 60 years residing in the fluorosis area of Khouribga and the non-fluorosis area of Beni-Mellal, Morocco. A total of 2378 subjects was studied. In the youngest age groups, more subjects and sextants from Khouribga than from Beni-Mellal were free of periodontal diseases. Conversely, in Beni-Mellal, subjects in the youngest age groups presented a higher mean number of sextants with calculus than those from Khouribga. In combining the 2 areas, 1.3% of the 2319 dentate subjects examined needed no treatment and 98.7% needed at least oral hygiene instructions (TN1). The present study, based on the CPITN index, demonstrated in both areas a high prevalence of gingivitis, and a relatively low prevalence of deep pocketing, occurring on the average in less than half a sextant in the total populations.

Adolescent↗
PubMed1989

National survey of caries prevalence in 6-15-year-old children in France.

The prevalence of dental caries in France is not known on a nationwide basis, despite the fact that a number of epidemiological studies have been conducted in various parts of the country. The aim of the present study was to provide a national baseline examination of the dental health of children in 1987 since, beginning in November, 1986, the sale of fluoridated salt began in France. A multi-stage probability sample of 19,366 children was selected as representative of the 6-to-15-year-old population. The sample covered all the 95 departments of France. Teams of well-calibrated examiners were constituted in each of the sixteen Faculties of Dental Surgery of France. The prevalence of caries for each age group was determined by means of DMFT, DMFS, dft, and dfs indices. Periodontal conditions were assessed by means of the Plaque Index (Silness and Löe, 1964), the Calculus Index (Marthaler, 1966), and the Gingival Index (Löe and Silness, 1963). Calculation of the mean DMFT index showed, respectively, 0.5 and 1.0 new carious teeth per year under and over the age of 11. The mean values of the DMFT index at ages 6, 12, and 15 were, respectively, 0.5, 4.2, and 6.9. Under the age of 11, the mean DMFS index increased by one between each successive age group and by nearly two over the age of 11. The mean values of the DMFS index at ages 6, 12, and 15 were, respectively, 0.8, 7.6, and 13.0. The percentage of caries-free children decreased from 32.2% at age 6 to 7.9% at age 15.

Adolescent↗
PubMed1989

The effects of airborne fluorides on oral conditions in Morocco.

The purpose of this study was to determine the prevalence and severity of dental caries and dental fluorosis, as well as various other oral conditions, in 2378 subjects (ages seven to 60) living in the fluoridated area of Khouribga and the non-fluoridated area of Beni Mellal, Morocco. The community index of dental fluorosis (CFI) ranged from 1.99 to 2.80 in the high-fluoride area: Over 90% of the population was affected, and more than one-third of the subjects showed moderate dental fluorosis. However, in Beni Mellal, more than 96% of the dentate subjects examined were free of dental fluorosis, and the CFI of 0.02 was considered not significant. Significant differences were observed between the two areas with respect to caries prevalence. DMFT and DMFS indices were markedly lower in the fluorosis area of Khouribga. The oral conditions of subjects appeared to be better in Khouribga, where the gingival and calculus indices were significantly lower than in Beni Mellal. The analyses of covariance showed no significant differences in plaque accumulation (PI) between the Khouribga and Beni Mellal samples. However, a close statistical correlation was found between PI and GI in Beni Mellal and Khouribga.

Adolescent↗
PubMed1989

[Sampling procedures of a national survey on the orodental status of 6-15-year-old children in France].

The multistage sampling procedure for the study of dental caries prevalence of 6 to 15 year old children of France consisted of 2 stratification variables and several levels of sampling. The geographical stratification controlled the distribution of the selected sample for the whole French territory. The second stratification variable consisted of the differentiation of urban and rural zones. The sampling rate was 1/400 and each schoolchild had the same probability of being selected. This rate gave samples of about 2,000 children for each age group, giving an adequate precision for the DMFT, DMFS and dft indices. This multistage sampling procedure was unbiased.

Adolescent↗
PubMed1989

[The orodental status of the French population 6-15 years of age].

A representative sample of 19,366 schoolchildren of France, aged 6 to 15 years, was randomly selected. Examiner teams from each of the 16 Faculties of Dental Surgery of France were trained together to be well calibrated. The dental caries prevalence was determined in each age group using the dft, dfs, DMFT and DMFS indices. The periodontal conditions were measured using the plaque index (Silness and Löe, 1964), the calculus index (Marthaler, 1966) and the gingival index (Löe and Silness, 1963). The mean DMFT index increased from 0.5 at age 6 to 6.9 at age 15 years. This index increased by 0.5 from one age group to the next until age 10, and from 1.0 from age 11 to age 15. The DMFS index increased from 0.8 to 13.0 between 6 and 15 years of age. In each age group, the numbers of carious and untreated surfaces were very similar to the number of filled surfaces. The percentage of children with caries-free permanent teeth decreased from 78.5% to 8.2% between 6 and 15 years of age. A direct relation was observed between the caries indices and the socio-economic category of the parents. The senior management and private professions presented the lowest indices.

Adolescent↗
PubMed1989

[Epidemiologic investigations on caries prevalence among schoolchildren in Brittany (France)].

1421 randomly selected 6- to 15-year-old Breton children were examined in 1987 in order to assess the prevalence of caries in permanent teeth. Methods proposed by Turlot & Cahen (1989) were used. At 6, 85.9% of all children were caries-free and at 15, only 5.3%. At 14, DMFT and DMFS rates reached 6.46 and 12.36, respectively. The differences of scores stated between boys and girls and between children from urban and rural regions were not statistically significant. Pits and fissures were more frequently affected than approximal and smooth surfaces. Since 1986, fluoridated domestic salt is available in France. Thus, the present investigation will serve to study the effects of this recently adopted preventive measure.

Adolescent↗
PubMed1988

Approximal caries diagnosis in epidemiological studies: transillumination or bitewing radiographs?

The aim of this study was to compare the results obtained by transillumination and bitewing radiography in the diagnosis of caries affecting approximal surfaces of molar and premolar teeth for epidemiological surveys. 3960 posterior approximal surfaces on the right side of 330 patients aged 5 to 35 years were examined using a transillumination probe with a 1.5 mm diameters light source (Oralum, Rocky Mountain, Denver, Colorado) and bitewing radiographs using a portable dental apparatus (Elin, Wien, 60kV, 15mA. Transillumination detected 89% of the carious lesions reaching dentine diagnosed on radiographs and no statistically significant differences were observed in the diagnosis yield of the two systems. However, transillumination detected only 45% of these lesions diagnosed from bitewings as being confined to the enamel. Transillumination also made it possible to detect approximal caries into dentine in teeth covered by orthodontic bands. Thus comparative study gives experimental support to the use of transillumination in large epidemiological studies. The transillumination method is however not suitable for epidemiological trials including caries confined to the enamel.

Adolescent↗
PubMed1988

[Epidemiological study of the oro-dental status of the children of the Alsace and the Franche-Comté].

Within a national epidemiological study conducted in France by the 16 Faculties of Dentistry, 946 school-children aged 6 to 15 years were randomly selected and examined in East of France. The Dental Faculty of Strasbourg studied the following departments: Doubs, Jura, Bas-Rhin, Haut-Rhin and Territoire de Belfort. Twenty per cent of the 12 year old children had a DMFT of 0, whereas by the age of 15 this percentage felt to 7%. The mean DMFT and DMFS of the 12 year old children were respectively of 4.6 and 8.7. The mean plaque index varied from 1.2 to 1.5 for all age groups. The mean calculus index increased progressively with age from 0.1 to 0.6. The mean gingival index was almost constant until the age of 8 (0.6 to 0.8). It reached 1.2 at 9 and remained unchanged until 15.

Adolescent↗
PubMed1987

Comparative study of oral conditions in schoolchildren of Strasbourg, France, 1974-85.

A representative sample of 1650 children randomly selected in the 6-15-yr-old schoolchild population of Strasbourg was examined by well-calibrated examiners. The prevalence of caries was determined with the DMFT, DMFS and dft indices using bitewing radiographs. Plaque, calculus and gingival indices were also determined. The results obtained were compared with the initial study of 1974 performed in Strasbourg using the same epidemiologic methods. Whereas no important variations were observed in caries prevalence of primary teeth, a significant reduction of caries activity was observed in DMFT and DMFS indices in all age groups. There was a reduction of these two indices of respectively 32% and 33% in the 12-yr-old children. The reduction was the most significant on approximal surface lesions. A statistically significant decrease of the calculus and gingival indices was also observed between 1974 and 1984. A less significant decrease was observed for the plaque index.

Adolescent↗