Why do we differ in number sense? Evidence from a genetically sensitive investigation.

Basic intellectual abilities of quantity and numerosity estimation have been detected across animal species. Such abilities are referred to as 'number sense'. For human species, individual differences in number sense are detectable early in life, persist in later development, and relate to general intelligence. The origins of these individual differences are unknown. To address this question, we conducted the first large-scale genetically sensitive investigation of number sense, assessing numerosity discrimination abilities in 837 pairs of monozygotic and 1422 pairs of dizygotic 16-year-old twin pairs. Univariate genetic analysis of the twin data revealed that number sense is modestly heritable (32%), with individual differences being largely explained by non-shared environmental influences (68%) and no contribution from shared environmental factors. Sex-Limitation model fitting revealed no differences between males and females in the etiology of individual differences in number sense abilities. We also carried out Genome-wide Complex Trait Analysis (GCTA) that estimates the population variance explained by additive effects of DNA differences among unrelated individuals. For 1118 unrelated individuals in our sample with genotyping information on 1.7 million DNA markers, GCTA estimated zero heritability for number sense, unlike other cognitive abilities in the same twin study where the GCTA heritability estimates were about 25%. The low heritability of number sense, observed in this study, is consistent with the directional selection explanation whereby additive genetic variance for evolutionary important traits is reduced.

[Traditional practices and exploitation of medicinal plants in odontostomatology in Ivory Coast]. / Pratiques traditionnelles et valorisation des plantes médicinales en odonto-stomatologie en Côte d'Ivoire.

Traditional medicine of which is a part traditional odontology occupies an important place within the African societies. It often constitutes the first appeal (80 % of the population) because of the high cost of the care, the incapacity of the human and material resources but also the faiths of the populations. This reality makes valuation of the traditional odontology a necessity. This study comes within this framework. It's a contribution for a better knowledge of practices and plants used in traditional odontology in Ivory Coast. So, after a presentation of some traditional knowledge's and their fields of application, the authors review studies made on the efficiency of plants in the prevention of tooth decay and the treatment of some oral diseases. The objective of these researches is to elaborate effective and financially affordable traditional improved drugs.

[Prevalence of anemia in patients undergoing dental care. A survey of 168 patients in the dental offices of the National Institute of Public Health in Adjame (Abidjan)]. / Prevalence de l'anemie chez les patients en consultation dentaire. Enquête réalisée sur 168 patients du cabinet dentaire de l'Institut National de Santé Publique d'Adjamé.

The aim of this study is the assessment of anaemia importance in patients consulting the dentist. 168 patients, all kind, of the dental office of the National Institute of Public Health of Abidjan, from 3 years ago, whom haematological statute is unknown are selected. Each person, after filling out a survey paper, is submitted to dental and haematological investigations. As result, 33% of our patients have anaemia. 95% of them are women. Pupils represent 48% of the anaemic.

Oral health status of 12-year-old schoolchildren in the province of Kadiogo, Burkina Faso.

OBJECTIVE: To assess the oral health status of 12-year-old schoolchildren in Kadiogo province, Burkina Faso. DESIGN: A cross-sectional epidemiological study in which a trained dentist performed clinical examinations. SETTING: Twenty primary schools in Kadiogo Province. SUBJECTS: Three hundred randomly selected children. OUTCOME MEASURES: Oral health status was recorded according to WHO criteria. Demographic characteristics (gender, type of school and geographic location) were also recorded. RESULTS: The results showed that 50% of the subjects examined were caries-free. The mean DMFT was 1.72+/-0.12 with a significant difference between urban and rural areas (P<0.05). Decayed teeth were untreated in this population, only 7% of whom had a healthy periodontium. Statistically significant differences were observed according to gender (P<0.02) and area (P<0.04). In the whole sample, 81% presented no malocclusion and only two questionable cases of fluorosis were observed. The rate of need for periodontal treatment was 83 to 100% in rural areas; 21% of the children needed at least one extraction and approximately 50% required conservative care. CONCLUSIONS: The mean DMFT found in this study placed the Kadiogo province in the low DMFT category defined by WHO and within the global goal of Health for All by the Year 2000 at 12 years old. However, decayed teeth were untreated, and periodontal status was very poor. There is therefore a need for appropriate preventive measures.

[Survey of methods of cleaning, decontamination, disinfection and sterilization in dental health services in tropical areas]. / Enquête sur les méthodes de nettoyage, décontamination, désinfection et stérilisation dans des services dentaires en zone tropicale.

The International Aid for Ontology (IAO) carried out this survey of hygiene in the dental health services of 5 French-speaking African countries in 1994, in association with the Faculty of Pharmaceutical and Biological Sciences of Paris. This study received support from the World Health Organization (WHO), the French Ministry for Cooperation and the European Community and the Ivory Coast Oral and Dental Hygiene and Health Committee (CIHSBD). Twenty-nine dental services from Benin (3), Burkina Faso (6), Ivory Coast (12), Mali (5), Niger (3) participated in this survey which gives an insight into the daily hygiene routines of these services. The cleaning, decontamination, disinfection and sterilization procedures for premises, dental equipment, instruments, hands and disposable items were investigated. No individual protocols are reported. Bench tops were cleaned or disinfected daily in 73% of centers and floors were cleaned or disinfected daily in 59% of centers. Walls were cleaned once per week in 44% of the centers. Hands were always washed between patients, with 68% of dental surgeons using only solid or liquid cleansing soaps and the others using antiseptic or disinfectant solutions. The dentist's chair was cleaned or disinfected daily in 68% of centers, mostly with soap (43%) or diluted bleach (23%). Vacuum equipment was cleaned with soap (50%) or diluted bleach (57%), with some surgeries using a combination of the two. Hand pieces and turbines were cleaned and disinfected after each use with alcohol (35%) or diluted bleach (26%) and were sterilized in 9% of centers. Instruments were sterilized with a Poupinel (63%), unspecified sterilizer (26%), autoclave (7%) or low temperature disinfection procedure (4%). Instruments were regularly sterilized in all centers. Single-use disposable items were often reused: 88% of centers reused gloves, 64% anesthetic cartridges and 32% disposable needles. This survey demonstrates that dentists do attempt to achieve appropriate hygiene standards despite difficult practice conditions, exacerbated by supply problems. In all applications, hygiene involves a succession of closely-related, logical steps, which form an asepsis chain aimed at preventing the transmission of infection. Our survey shows that fundamental elements of hygiene require attention to achieve this aim. The cleaning, disinfection and sterilizing of floor surfaces and equipment should be improved and more widespread use made of disposable items. It is important to define the hygiene level required for particular treatments, taking into account the oral and dental micro flora and whether the equipment has been decontaminated, disinfected or sterilized. A piece of equipment is decontaminated if it has been mechanically cleaned and decontaminated. It is disinfected if these steps are followed by rinsing with sterile water, drying and conditioning. An item is described as sterilized if it is cleaned, decontaminated, rinsed, dried, conditioned and then sterilized. We found that a wide variety of chemicals were used to clean hands, surfaces and equipment. The nature and appropriate methods of use of these chemicals were not widely known. Understanding the chemical composition of these chemicals makes it possible to classify them into cleaning agents, detergents, decontaminating agents and disinfectants. The definition, choice and use of antiseptics and disinfectants should be strictly controlled. It is also vital that single-use disposable items are used only once and are never reused. Hygiene in the dental surgery is a chain of processes aimed at protecting the patient and the medical staff. There are many links in the chain, involving floor and surface hygiene, hand washing by dentists and dental assistants, washing of surgery linen and treatment of equipment. Dental practitioners should continually focus on ensuring that the chain of hygiene procedures is not broken, in their own interests as well as in those of their patients.

[Behavior linked to orodental health in 12-year-old students in the province of Kadiogo, Burkina Faso]. / Comportements liés à la santé bucco-dentaire des élèves de 12 ans de la province du Kadiogo, Burkina Faso.

The authors present the results of a study carried out within the context of a diagnosis of the state of dental health among 300 twelve years old students in school in the province of Kadiogo (Burkina Faso). The data collected by questionnaires explore the range of behaviours linked to dental health: dental hygiene, eating habits, use of fluoride and use of dental health services. Half of students report that they brush their teeth at least once a day. Among them, there are 2 girls out of three, and one boy out of two. For half of the children, their mothers are the main people who teach them how to brush their teeth. For three children out of four, a tooth brush and tooth paste are the most common methods. Roughly 17% understand the usefulness of fluoride and 70% have never heard of it. Four children out of five consume sugared drinks on a daily basis. 85% say they have never been to the dentist. The information collected could serve as a base for the development and implementation of health promotion and education programmes for dental health within schools.

[Supernumerary teeth and orthodontic treatment]. / Dents surnumeraires et traitement orthodontique.

According to the orthodontist supernumerary teeth on dental arches necessitate a special analysis of the occlusion to decide which to keep and which ones to pull out. Then he must solve the problem of the new occlusion to have. Thus in this study the authors, from their personal experiences of treatment of cases about supernumerary teeth go through the matter.

[The aging face in Black Africans]. / Senescence faciale chez le Negro-Africain.

The face is the part of the human body that most reflects external marks of time. The change of this region concerns the body support as well as the musculo-cutaneous surface. In this survey, we have described its evolution during the life, in the Black African, particularly on the esthetical plane.

[Enamel asiderosis and dental caries]. / Asiderose amelaire et carie dentaire.

This study investigated the effect of the Stephan 580 cariogenic diet on the iron containing enamel in rat teeth. Forty Wistar rats (male and female) weighing 120 g, were given the Stephan 580 cariogenic diet for 21 days and compared to another similar group of forty rats weighing 120 g, given the normal A03 non cariogenic diet. The results of Energy Dispersive x-ray Analysis for iron showed a lack of detection of iron in the carious enamel of rats fed with the Stephan 580 cariogenic diet. Iron was found only in the non-carious enamel of control rats. The Stephan 580 cariogenic diet induced enamel asiderosis in rat teeth.

[Complications of injuries to deciduous teeth]. / Complications des traumatismes des dents temporaires.

The traumatisms of the temporary teeth are very frequent. They are bound to the acquirement of the march, to the games, to the sport and to the accidents of the public way. Favoured by the presence one improved proalveoly, they constitute a dental emergency of makes some important risks of complications. Indeed, these traumatisms, in case of belated conference and/or of maladjusted treatment or conducted pain, could induce some complications and have some aesthetic and functional after effects on the dental germ underlying. Some of these complications observed in some patients are stakes in evidence by some iconographic illustrations.

[Replacement of deciduous incisors in children: psychological aspects]. / Remplacement des incisives temporaires chez l'enfant: intérêt psychologique.

The absence of the temporary incisors could be to a genetic illness or to some multiple premature extractions. These extractions are the aftermaths of the carious lesions or some traumatisms underwent by the temporary incisors. Beyond measure the loss of the space, the premature loss some temporary incisors very often assign the relational development of the child and disturb its psychological development and the aesthetic function. Across some cases clinics, the authors show that the replacement of the temporary incisors is the therapeutic ideal solution. Indeed, the child prosthesis, replacing the temporary absent incisors, solves the psychological, aesthetic and relational problems of the child.

[Comparison of the clinical detection and the biological detection of dental caries]. / Comparaison de la détection clinique et de la détection biologique de la carie dentaire.

Different methods can be used to detect dental caries. The comparison of the clinical detection by the use of explorer and mirror to the biological detection by the measurement of alkaline phosphatase activity (ALP) in 107 men of 19 to 25 years old was performed. Biological detection reveals more active caries(APL activity > 116 Ul/L) than the clinical one. Absence of caries activity is expressed by an ALP activity between 86 and 116 Ul/L. The Chi 2 test shows that alkaline phosphatase is a statistically significant marker of dental caries and more it reveals its carious activity.

[Oral health care practices in Abidjan]. / Itinéraire thérapeutique en Odonto-Stomatologie à Abidjan.

Abidjan, the economical capital of Ivory Coast has a CAO of 2.7 with index O practically nil. The professional density is one surgeon for 12.000 inhabitants. Abidjan population, despite the requirements in increasing care has not recourse to the dental surgeons for their assumption of responsibility. The general objective of our study is to describe the therapeutic itinerary in odonto-stomatology of the Abidjan population. We have realised a questionnaire survey beside of population sample. The results show that 25 per cent of our population gives up care despite the presence of pain or embarrassment. Our study has allowed highlighting all the other recourses to the care. Indeed, the people who give up the care have much other recourse which has be identified in order of importance: the modern and traditional self-medication. Let us note in our study, that the choice of dental surgeon knows a constant evolution from the first to the third recourse. The lack of financial means constitutes however the first obstacle at the accessibility to the oral care in Ivory Coast.

[Therapeutic possibilities for multiple caries in children]. / Possibilites therapeutiques des polycaries chez l'enfant.

The exaggerated consumption of sugars under its various associate shapes to an insufficiency of mouth and tooth hygiene could drag some tooth decays. These tooth decays, when they demonstrate, leads to a destruction of the temporary teeth, with for corollaries of the aesthetic and functional problems. The therapeutic are not always apparent especially when there is coexistence of coronary destruction to juxtapose to the gum without reaching pulp with some precocious a toothlessing. The authors, across some cases clinics treated to the breast of service of Paediatric Dentistry shows different types of therapeutic possibilities in function of the shapes clinics. He was about conservative treatments or of extraction, of prothesis restorations to the aide of the Crown order form, of infantile removable prosthesis and of composite prosthesis.

[Influence of food quality and quantity on children's teeth]. / Influence de la qualité et de la quantité de l'alimentation sur les dents chez l'enfant.

Sugar and tooth decays are bound closely. The mechanisms of destruction of the tooth from the glycolyse are known. The role played by the food in the development of the caries is unique. Foods sweetened of all ways, rich in sucrose are responsible of the intervening of the carious lesions. The transformation of the fermentable sugars in lactic with the absence of hygiene and the action conjugated of the bacteria leads to tooth decays in temporary and permanent denture that evolve very quickly in the absence of treatment. Reasons for which the authors put in evidence in this survey, the influence of the food sweetened on the teeth at the children while showing the cases of caries and its complications due to the excessive consumption of fermentable hydrates of carbon.

[Orodental diseases and school absences. Evaluation of a school population of 278 students. Preliminary study]. / Affections bucco-dentaires et absences scolaires. Evaluation sur une population scolaire de 278 élèves. Etude préliminaire.

In the framework of an important evaluation survey on absences at work position due to bucco-dental problems, a preliminary study in undertaken in school environment on a sample of 278 children attending examination classes from Abidjan three districts (Adjamé, Williamsville, Cocody). Results show that: 34.89% among children have been absent at least one time of which 19.78% for pulp pain, 22.66% of the sample have got a rest and for 14.02% among them, the rest was at least a day. These absences results in a waste in annual hourly volume from 2.69% to 8.08% of the annual hourly quota in terms of dispensed Cowes's in Ivory Coast primary schools. The results show that bucco-dental pathologies and their corresponding i.e. school absences have a repercussion on pupils attendance regularity at school and with no doubt on schools results. They indicate the necessity to put an emphasise on the prevention and the early treatments of these affections.

[Treatment of protruding upper incisors using the Hawley appliance]. / Le traitement de la proalveolie incisive superieure par la plaque de Hawley.

Early treatment of upper protrused incisors prevents these teeth from traumatism. The plate of HAWLEY, properly used, is recognised for the correction of this malocclusion.

[Ivorian typology: study of the crown dimensions of the first permanent molar]. / Typologie ivoirienne: etude des dimensions coronaires de la premiere molaire permanente.

A dental morphology study is of great importance because it allows norms to be established which are adapted to the Ivorian situation. After a study of the canal morphology, we became involved in a study of the canal dimensions of the first permanent molars amongst Ivorian children. As a part of the 260 mouldings taken from 67 boys and 63 girls, we measured the following diametres: the diametre masio-distal (O-M-D) taken between the edge of the mesial bone and the edge of the distal bone. the biggest vestibulo-lingual coronary diametre (OV-LC). the diametre of the vestibulo-lingual at the level of the occlusal table (OV-LC). The data collected allowed us to reach the following conclusions: the first secondary molar with a M-D diametre (10.64 mm) is more important than the M-D diametre of its homologeous upper (10.15). however there is no significant difference between the OV-LC diametre of the first maxillary molar and that of the first mandibular molar. concerning the M-D or V-L diametres, the difference between the left side of the maxillary as with the mandibular is negligble. It's worth noting that the first permanent molar is smaller for girls when compared to boys, as well as their M-D diametres compared to their V-L. A comparative study between the TALLEC and MARSEILLIER plates showed that: the first upper molar for Ivorian children has a M-D diametre practically identical to that of European children, however the V-L and OV-LC diametres are smaller. the first bottom molar slightly bigger in all M-D and V-L diametres in Ivorian children in comparison to European children.

[Cartography of fluoride in the Ivory Coast (partial study)]. / Cartographie du fluor en Cote D'Ivoire (etude partielle).

The authors report on a study done in the Côte d'Ivoire, about the amount of fluoride in drinking water. The cartography of fluoride shows amounts lower than 0.7 ppm. This small amount of fluoride partially explains the increase in the number of dental caries in the Côte d'Ivoire.

[Caries of the first permanent molar in Ivory Coast children]. / A propos de l'atteinte carieuse de la premiere molaire permanente-au sein d'une population infantile ivoirienne.

The authors study dental decay in the first permanent molar among school children in Dimbokro (Côte d'Ivoire). The study, carried out on 1050 children aged between 7 to 16, revealed a low CAO index but a frequency index greater than 50%.