Selective excavation and ozone therapy: new frontier of mini-invasive caries treatment in MIH paediatric patients. A case report.

BACKGROUND: The term hypomineralisation of molars and incisors (MIH), introduced in 2001 by Weerheijm et al., describes a clinical state of hypomineralisation of permanent molars with frequent involvement of the incisors. MIH is considered a global dental problem with a prevalence ranging from 2.4% to 40.2% in the entire world paediatric population. The continuous increase in the prevalence of enamel anomalies, including MIH, indicates the need to define new intervention protocols based on the technological advances that are revolutionising paediatric dentistry. The use of ozone associated with the selective and minimally invasive excavation of the dental tissue combines the antibacterial properties of the gas with an ultra-conservative approach aimed at the maximum conservation of the dental tissue. The operative protocol described can be an important tool in the prevention and treatment of MIH. The aim of this work is to illustrate an operative clinical protocol based on the combined use of selective excavation and ozone for the treatment of carious lesions in paediatric patients with MIH.

Prevalence, distribution, characteristics and associated factors of molar-incisor hypo-mineralisation among Libyan schoolchildren: a cross-sectional survey.

BACKGROUND AND AIM: This study aimed to assess the prevalence and clinical status of molar incisor hypomineralisation (MIH) and other enamel defects and associated factors in Libyan children. METHODS: A cross-sectional survey of a randomly selected sample of 8- to 10-year-old Libyan school children was conducted in the city of Benghazi, Libya in 2019. The children were assessed for the presence of MIH and enamel defects according to EAPD evaluation criteria. The survey was supplemented by a questionnaire, completed by parents, about potential associated factors occurring before, around and after birth. Association with risk indicators was assessed using chi-square and Mann-Whitney U tests. RESULTS: One thousand forty-seven children returned complete questionnaires and attended the clinical examination, with 87% response rate. MIH was the most common form of enamel defects, affecting 162 (15.5%) children. The average number of MIH affected teeth was 3.54 (SD = 1.82). There were no statistically significant associations between the prevalence of MIH and health or demographic characteristics except for the history of early childhood health problems (P = 0.047). CONCLUSIONS: In Libyan children, MIH appeared to be the most prevalent type of enamel defects affecting 15.5% of the participants. Although not statistically significant, MIH appeared to be associated with prenatal, perinatal and post-natal challenges.

Valkyries: Was gender equality high in the Scandinavian periphery since Viking times? Evidence from enamel hypoplasia and height ratios.

Scandinavian countries currently have very high values of female autonomy. Was this already the case in Viking Times? In this study, we trace the roots of gender equality in the Scandinavian periphery over the past two millennia. We evaluate and recommend a new measure of early gender equality: relative enamel hypoplasia values of males and females. This new indicator allows us to trace relative health and nutritional equality, using archaeological evidence. We find that Scandinavian women in the rural periphery already had relatively good health and nutritional values during the Viking era and the medieval period thereafter. The corresponding value is 0.8 equality advantage for Scandinavian women, whereas in the rest of Europe most values fall in a band around 1.2 ratio units. This suggests that the currently high gender equality had a precedence during the Middle Ages.

Fluoride/vitamin D tablet supplementation in infants-effects on dental health after 10 years.

OBJECTIVE: We examined whether fluoride/vitamin D supplementation in the first year of life is associated with caries or molar incisor hypomineralization (MIH) at 10 years of age. METHODS: The study population consisted of 406 children for whom information on fluoride/vitamin D supplementation during the first year of life was available. Dental examination at the age of 10 included caries and MIH registration. The results of logistic regression models were adjusted for gender, age, BMI, parental education, and equivalent income. RESULTS: Children receiving supplementation during the entire first year of life had a significantly lower probability of having caries-related restorations in primary teeth in comparison to those who received supplementation for less than 6 months (fluoride supplementation: odds ratio (OR) for d3-4mfs 2.47 (1.32-4.63), for fs 2.70 (1.43-5.10); vitamin D supplementation: OR for d3-4mfs 2.08 (1.00-4.32), fs 2.50 (1.19-5.25)). The majority of logistic regression analyses indicated no association between supplementation and MIH. CONCLUSIONS: It was found a consistent significant caries-preventive effect in the primary dentition of children who received fluoride (256/372)/vitamin D supplementation (274/376) in all 12 months over the first year of life; no effects were observed for permanent dentition. The high parental interest in supplementation is linked to an imbalance of the study groups. Furthermore, tooth brushing frequency, use of fluoride toothpastes and/or other oral hygiene products were not recorded during the observation period which may also confound the results. CLINICAL RELEVANCE: Fluoride/vitamin D supplementation can be used in children for preventing caries in the primary dentition.

Comparación de la prevalencia de hipomineralización molar incisiva en niños con diferente cobertura asistencial en las ciudades de Buenos Aires (Argentina) y Montevideo (Uruguay) / Comparison of the prevalence of molar incisor hypomineralization among children with different health care coverage in the cities of Buenos Aires (Argentina) and Montevideo (Uruguay)

El objetivo fue comparar la frecuencia de la hipomineralización molar incisiva (HMI) entre niños con diferente cobertura de salud en Buenos Aires y Montevideo. Se diseñó un estudio transversal, observacional y descriptivo con los nacidos entre 1993-2003, asististidos en las Cátedras de Odontología Integral Niños (Universidad de Buenos Aires) y de Odontopediatría (Universidad de la República) y en cinco clínicas privadas, entre abril y diciembre 2010. Se conformaron dos grupos: A (Buenos Aires; n=1.090) y B (Montevideo; n=626). El diagnóstico clínico fue realizado por examinadores calibrados (Kappa: 0,94) con los criterios de Mathu-Muju y Wright. Los resultados mostraron una prevalencia de HMI en A del 16,1% y en B del 12,3% (p=0,03), con diferencias significativas entre los sectores público y privado en ambos grupos (A p=0,0008; B p=0,0004) y una correlación positiva entre la HMI y el año de nacimiento (A p=0,001; B p=0,005) Los resultados permiten concluir que la HMI es una patología emergente y su prevalencia se relaciona al año de nacimiento y al acceso al cuidado de salud.

The aim of this study was to compare the prevalence of molar incisor hypomineralization (MIH) among children with different health care coverage in Buenos Aires and Montevideo. An observational, cross-sectional and descriptive study was designed, considering children born from 1993-2003 who were seen in the Chairs of Comprehensive Children's Dentistry (Universidad de Buenos Aires) and of Pediatric Dentistry (Universidad de la República) and at five private dental offices between April and December 2010. Two groups were defined: A (Buenos Aires; n=1,090) and B (Montevideo; n=626). The clinical diagnosis was carried out with calibrated examiners (Kappa: 0.94) using the Mathu-Muju and Wright criteria. The prevalence of MIH was found to be 16.1% in A and 12.3% in B (p=0.03), with statistically significant differences between the public and private care sectors in both groups (A p=0.0008; B p=0.0004) and a positive correlation between MIH and year of birth (A p=0.001; B p=0.005). The results show that MIH is an emerging pathology and that MIH prevalence is related to year of birth and access to health care.

The possible correlation between dental enamel hypoplasia and a historic natural disaster in the Roman population of Herculaneum (79 AD - central Italy).

Dental enamel hypoplasia is usually read as a sign of a systematic growth disturbance during childhood. Following the analysis of human teeth from Herculaneum (79 AD, Central Italy), the authors focused on linear enamel hypoplasia (LEH) manifestations in order to delineate a possible correlation between their frequency and distribution and the earthquake that occurred in 62 AD, which is well documented in historical literature. The human remains from Herculaneum were buried at the same time as the Vesuvius eruption and represent an exceptional snapshot of life in the Roman Imperial Age. The Goodman and Rose method (1990) was used for attributing an "age at the moment of stress" for every skeleton in order to delineate the epidemiology of the enamel hypoplasia. When LEH frequency was analysed by age, two different age groups showed relevant patterns of hypoplasia: the first peak was evident in individuals between 14 and 20 years who were younger than 6 years at the time of the 62 AD earthquake, and a second peak was noted in adults of 30 +/- 5 years old, which suggests the presence of another stressful event that occurred 10 years before the earthquake, around 53 AD. The bimodal distribution of enamel hypoplasia could be the consequence of two different historical periods characterized by instability in the food supply, unhygienic conditions, and epidemic episodes; our data suggest that the first peak could be related to a decline in health status as an effect of the 62 AD earthquake. The relationship between recent natural disasters and variations in health status in modern populations is well documented in scientific literature. Our research represents the first attempt to correlate the status of health to an earthquake of known date in an archaeological population.

Morbidity in the marshes: using spatial epidemiology to investigate skeletal evidence for Malaria in Anglo-Saxon England (AD 410-1050).

Concerns over climate change and its potential impact on infectious disease prevalence have contributed to a resurging interest in malaria in the past. A wealth of historical evidence indicates that malaria, specifically Plasmodium vivax, was endemic in the wetlands of England from the 16th century onwards. While it is thought that malaria was introduced to Britain during the Roman occupation (AD first to fifth centuries), the lack of written mortality records prior to the post-medieval period makes it difficult to evaluate either the presence or impact of the disease. The analysis of human skeletal remains from archaeological contexts is the only potential means of examining P. vivax in the past. Malaria does not result in unequivocal pathological lesions in the human skeleton; however, it results in hemolytic anemia, which can contribute to the skeletal condition cribra orbitalia. Using geographical information systems (GIS), we conducted a spatial analysis of the prevalence of cribra orbitalia from 46 sites (5,802 individuals) in relation to geographical variables, historically recorded distribution patterns of indigenous malaria and the habitat of its mosquito vector Anopheles atroparvus. Overall, those individuals living in low-lying and Fenland regions exhibited higher levels of cribra orbitalia than those in nonmarshy locales. No corresponding relationship existed with enamel hypoplasia. We conclude that P. vivax malaria, in conjunction with other comorbidities, is likely to be responsible for the pattern observed. Studies of climate and infectious disease in the past are important for modeling future health in relation to climate change predictions.

Prevalence of molar-incisor hypomineralization (MIH) in children seeking dental care at the School of Dentistry of the university of Buenos Aires (Argentina) and University of La Republica (Uruguay)

Los datos sobre prevalencia de MIH en Latinoamérica son escasos. Los objetivos de este trabajo son comparar la prevalencia de MIH en niños que demandaron atención en las Cátedras de Odontología Integral Niños de la Universidad de Buenos Aires (FOUBA) y de Odontopediatría de la Universidadde la República (UdelaR) y analizar en ambas unidades académicas la distribución según la variable año de nacimiento, sexo, edad, número de piezas afectadas y máxima severidaden molares e incisivos. 9 docentes de ambas facultades (Kappa= 0.94) evaluaron durante el periodo lectivo del año 2010 a todos los niños nacidos entre 1993 y 2003 que presentabanerupcionados los 4 primeros molares y los 8 incisivos permanentes y que concurrieron espontáneamente a ambasunidades académicas para su atención odontológica integral. Después de una profilaxis, las piezas fueron clínicamente evaluadas con luz del foco, previamente secadas, registrando en planillas diseñadas para tal fin, sexo, año de nacimiento, institución de pertenencia, presencia de MIH, número de incisivosy molares afectados y máximo grado de severidad. La severidad se cuantificó a través de su aspecto en: Normal (0), Blanco crema (1), Amarillo marrón (2) y Pérdida de esmalte (3). Se conformaron dos grupos: UBA: A (n=512) y UdelaR: B (n=463). Los datos obtenidos fueron analizados estadísticamente utilizando porcentajes con sus correspondientes intervalos de confianza del 95 por ciento para la descripción de la prevalencia y otras variables cualitativas; Test Exacto de Fisher para la comparación de las proporciones y Test de Welch para la comparación de las edades. Resultados: Fueron evaluados 975 niños, edad media: 11.6 ± 2,67 años. No se observaron diferencias significativas entre los grupos en relación a las variables edad (p=0.95) y sexo (p=0.30). La prevalencia de MIH del total de la muestra fue de 6.56 por ciento, sin diferencias significativas entre A y B (p= 0.76).

Prevalence of molar-incisor hypomineralization (MIH) in children seeking dental care at the School of Dentistry of the university of Buenos Aires (Argentina) and University of La Republica (Uruguay)

Los datos sobre prevalencia de MIH en Latinoamérica son escasos. Los objetivos de este trabajo son comparar la prevalencia de MIH en niños que demandaron atención en las Cátedras de Odontología Integral Niños de la Universidad de Buenos Aires (FOUBA) y de Odontopediatría de la Universidadde la República (UdelaR) y analizar en ambas unidades académicas la distribución según la variable año de nacimiento, sexo, edad, número de piezas afectadas y máxima severidaden molares e incisivos. 9 docentes de ambas facultades (Kappa= 0.94) evaluaron durante el periodo lectivo del año 2010 a todos los niños nacidos entre 1993 y 2003 que presentabanerupcionados los 4 primeros molares y los 8 incisivos permanentes y que concurrieron espontáneamente a ambasunidades académicas para su atención odontológica integral. Después de una profilaxis, las piezas fueron clínicamente evaluadas con luz del foco, previamente secadas, registrando en planillas diseñadas para tal fin, sexo, año de nacimiento, institución de pertenencia, presencia de MIH, número de incisivosy molares afectados y máximo grado de severidad. La severidad se cuantificó a través de su aspecto en: Normal (0), Blanco crema (1), Amarillo marrón (2) y Pérdida de esmalte (3). Se conformaron dos grupos: UBA: A (n=512) y UdelaR: B (n=463). Los datos obtenidos fueron analizados estadísticamente utilizando porcentajes con sus correspondientes intervalos de confianza del 95 por ciento para la descripción de la prevalencia y otras variables cualitativas; Test Exacto de Fisher para la comparación de las proporciones y Test de Welch para la comparación de las edades. Resultados: Fueron evaluados 975 niños, edad media: 11.6 ± 2,67 años. No se observaron diferencias significativas entre los grupos en relación a las variables edad (p=0.95) y sexo (p=0.30). La prevalencia de MIH del total de la muestra fue de 6.56 por ciento, sin diferencias significativas entre A y B (p= 0.76).(AU)

Prevalence of molar incisor hypomineralization in the city of Buenos Aires

La prevalencia de la hipomineralización molar incisva (MIH) es en nuestro país aún desconocida. Los objetivos de este estudio fueron: estimar la prevalencia de MIH en un grupo de niños que demandaron atención en la Ciudad Autónoma de Buenos Aires; analizar su distribución de acuerdo al año de nacimiento, y comparar prevalencia y severidad de acuerdo a la accesibilidad a los servicios de salud. Se diseñó un estudio prospectivo, observacional, transversal y descriptivo, sobre la población infantil que demandó atención en la Cátedra de Odontología Integral Niños y en 3 consultorios odontopediátricos de los miembros del equipo de trabajo, ubicados en la ciudad de Buenos Aires (Kappa 0.933 0.911-0.952), en el período comprendido entre abril y agosto de 2010. Fueron incluidos todos los niños nacidos entre 1993 y 2003 que presentaban erupcionados los 4 primeros molares y los 8 incisivos permanentes. Después de una profilaxis, las piezas fueron clínicamente evaluadas con luz del foco, previamente secadas, registrando en planillas diseñadas para tal fin, sexo, fecha de nacimiento, tipo de acceso a la atención, presencia de MIH, número de incisivos y molares afectados y máximo grado de severidad registrado en cada pieza. Para el análisis de los datos se utilizaron porcentajes, test exacto de Fisher y regresión lineal. Fueron evaluados 1098 niños de 11.3 años (11.08-11.39). La prevalencia obtenida fue del 15.9 por ciento (13.8-18.2). Con respecto al año de nacimiento se observó una correlación positiva y altamente significativa (p<0.0001). El grupo A (modalidad prepago) quedó conformado por 586 niños y el B (hospital público universitario) por N=512. En A, la prevalencia de MIH fue deld 24.40 por ciento y en B de 6,44 por ciento (p<0,0001). El 37 por ciento (32.2-42) de los molares afectados de A y el 13.7 por ciento (6.7-23.8) de B presentaban lesiones de grado 3, con pérdida de esmalte (p0,0001). En este estudio, la MIH se presentó como una patología frecuente.

Oral and physiological paleohealth in cold adapted peoples: Northeast Asia, Hokkaido.

This paper examines variables useful in reconstructing oral (caries, antemortem tooth loss, alveolar defects) and physiological (cribra orbitalia, linear enamel hypoplasia) well-being in two bioarchaeological assemblages from Hokkaido, Japan: Okhotsk (n = 37 individuals) and Jomon (n = 60). Findings are compared and contrasted with each other, with published series from Honshu Japan, and samples from climatically near-equivalent Alaska. It was found that more meaningful comparisons of Hokkaido paleohealth could be made with Alaskan material, rather than the more southerly Jomon. Results were ambiguous with respect to physiological well-being. Low levels of LEH in the cold-adapted samples suggest operating in arctic and subarctic environments with marine-based subsistence regimes is not physiologically expensive. However, the relatively high levels of cribra orbitalia in Hokkaido, relative to Alaska, suggest the picture is not straightforward: the reasons for elevated cribra orbitalia in Hokkaido are unclear. The subarctic and arctic samples formed three broadly similar groupings in terms of oral health profiles: (1) Aleuts and Eskimo; (2) Ipiutak and Tigara; (3) Hokkaido Jomon, Okhotsk, and Kodiak Island. Differences between these groupings could be explained with a combination of sample demographics and subsistence orientations. The extremely high frequency of caries in one sample, caribou hunting Ipiutak, may have been influenced by factors such as low levels of dietary magnesium and potentially cariogenic foodstuffs, such as preparations of caribou stomach contents. It was concluded that oral health profiles are potentially sensitive to differences in subsistence strategies among cold-adapted hunter-gatherers, although they lack predictive value.

Dental remains from the Grotte du Renne at Arcy-sur-Cure (Yonne).

Human remains associated with the earliest Upper Paleolithic industries are sparse. What is preserved is often fragmentary, making it difficult to accurately assign them to a particular species. For some time it has been generally accepted that Neandertals were responsible for the Châtelperronian and anatomically modern humans for the early Aurignacian industries. However, the recent re-dating of several of the more-complete modern human fossils associated with the early Aurignacian (e.g., Vogelherd) has led some to question the identity of the makers and the context of these early Upper Paleolithic industries. The Grotte du Renne at Arcy-sur-Cure, France has yielded many hominin remains, from Mousterian, Châtelperronian, Aurignacian, and Gravettian layers. Previously, a child's temporal bone from the Châtelperronian Layer Xb was recognized as belonging to a Neandertal; however, most of the teeth from Châtelperronian layers VIII-X remain unpublished. We describe the dental remains from the Châtelperronian layers, place them in a comparative (Mousterian Neandertal and Upper Paleolithic modern human) context, and evaluate their taxonomic status. The teeth (n = 29) represent a minimum of six individuals aged from birth to adult. The permanent dental sample (n = 15) from the Châtelperronian layers of Arcy-sur-Cure exhibits traits (e.g., lower molar mid-trigonid crest) that occur more frequently in Neandertals than in Upper Paleolithic modern humans. Furthermore, several teeth show trait combinations, including Cusp 6/mid-trigonid crest/anterior fovea in the lower second molar, that are rare or absent in Upper Paleolithic modern humans. The deciduous teeth (n = 14) significantly increase the sample of known deciduous hominin teeth and are more similar to Mousterian Neandertals from Europe and Asia than to Upper Paleolithic modern humans. Thus, the preponderance of dental evidence from the Grotte du Renne strongly supports that Neandertals were responsible for the Châtelperronian industry at Arcy-sur-Cure.

Health of infants in an Imperial Roman skeletal sample: perspective from dental microstructure.

This study examines general health in the first year of life of a population of 127 subadults from the Imperial Roman necropolis of Isola Sacra (2nd-3rd century ACE). Health status was determined by analyzing 274 deciduous teeth from these children for Wilson bands (also known as accentuated striae), microscopic defects caused by a disruption to normal enamel development arising from some generalized external stressor. While macroscopic enamel defects, or hypoplasias, have long been used as proxies of general population health, we believe that this is the first population-wide study of microscopic defects in deciduous teeth. We used microstructural markers of enamel to attach very precise chronologies to Wilson band formation that allowed us to calculate maximum prevalence (MAP) and smoothed maximum prevalence (SMAP) distributions to portray what we believe to be a realistic risk profile for a past population of children. There appear to be two periods of high prevalence, the first beginning around age 2 months and continuing through month 5, and the second higher period beginning around month 6 and continuing through month 9. These results are discussed in light of historical records of Roman childhood rearing practices.

Enamel hypoplasias and physiological stress in the Sima de los Huesos Middle Pleistocene hominins.

This study presents an analysis of linear enamel hypoplasias (LEH) and plane-form defects (PFD) in the hominine dental sample from the Sima de los Huesos (SH) Middle Pleistocene site in Atapuerca (Spain). The SH sample comprises 475 teeth, 467 permanent and 8 deciduous, belonging to a minimum of 28 individuals. The method for recording PFD and LEH is discussed, as well as the definition of LEH. The prevalence of LEH and PFD in SH permanent dentition (unilateral total count) is 4.6% (13/280). Only one deciduous tooth (lower dc) showed an enamel disruption. Prevalence by individual ranges from 18.7-30%. The most likely explanation for the relatively low LEH and PFD prevalence in the SH sample suggests that the SH population exhibited a low level of developmental stress. The age at occurrence of LEH and PFD was determined by counting the number of perikymata between each lesion and the cervix of the tooth. Assuming a periodicity of nine days for the incremental lines, the majority of LEH in the SH sample occurred during the third year of life and may be related to the metabolic stress associated with weaning.

Prevalence and the duration of linear enamel hypoplasia: a comparative study of Neandertals and Inuit foragers.

As a dental indicator of generalized physiological stress, enamel hypoplasia has been the subject of several Neandertal studies. While previous studies generally have found high frequencies of enamel hypoplasia in Neandertals, the significance of this finding varies with frequencies of enamel hypoplasia in comparative samples. The present investigation was undertaken to ascertain if the enamel hypoplasia evidence in Neandertals suggests a high level of physiological stress relative to a modern human foraging group, represented here by an archaeological sample of Inuit from Point Hope, Alaska. Unlike previous studies, this study focused specifically on linear enamel hypoplasia (LEH), emphasizing systemic over localized causes of this defect by considering LEH to be present in an individual only if LEH defects occur on two anterior teeth with overlapping crown formation periods. Moreover, this study is the first to evaluate the average growth disruption duration represented by these defects in Neandertals and a comparative foraging group. In the prevalence analysis, 7/18 Neandertal individuals (from Krapina and southern France) and 21/56 Neandertal anterior teeth were affected by LEH, or 38.9% and 37.5% respectively. These values do not differ significantly from those of the Inuit sample in which 8/21, or 38.1% of individuals, and 32/111, or 28.8% of anterior teeth were affected. For the growth disruption duration analysis, 22 defects representing separate episodes of growth disruption in Neandertals were compared with 22 defects in the Inuit group using three indicators of duration: the number of perikymata (growth increments) in the occlusal walls of LEH defects, the total number of perikymata within them, and defect width. Only one indicator, the total number of perikymata within defects, differed significantly between the Inuit and Neandertal groups (an average of 13.4 vs. 7.3 perikymata), suggesting that if there is any difference between them, the Inuit defects may actually represent longer growth disruptions than the Neandertal defects. Thus, while stress indicators other than linear enamel hypoplasia may eventually show that Neandertal populations were more stressed than those of modern foragers, the evidence from linear enamel hypoplasia does not lend support to this idea.

The role of early dietary habits in dental caries development.

Early Childhood Caries (ECC) is a serious dental condition that occurs during the first three years of life and is associated with the early intake of sugary foods, drinks, or snacks. There is now evidence that early malnutrition episodes could lead to delay in the eruption of primary teeth and possibly to increased caries prevalence. Significant correlations are present between the intakes of carbohydrates, proteins, and fats during infancy and several years later in life. Infants' dietary intake is also significantly correlated with the dietary intake of their mothers. Supplementing milk with vitamins during the first several years of life leads to reduction in the prevalence of linear enamel hypoplasia, a condition that may be associated with future development of dental caries. There are equivocal findings concerning the value of using dietary habits to predict caries incidence during the first three years of life. There is a need for development of educational, nutritional, and prevention programs targeting mothers and infants and for research on effective methods to prevent Early Childhood Caries.

Environmental causes of enamel defects.

A large number of causes of enamel defects, both environmental and genetic, have been described. However, many of these are derived from case histories and studies of individual conditions. What is needed now is a systematic investigation of the problem. The first requirement in exploring the aetiology further is the standardization of both the clinical diagnosis and the descriptive terminology. This has been provided by the Fédération Dentaire Internationale Developmental Defects of Enamel Index. Comparing studies using standardized methods, including this index, has highlighted areas for closer investigation. The total prevalence of enamel defects in a population needs to be established as a baseline for studies on aetiology. Sixty-eight per cent of 1518 school children in London have enamel defects in the permanent dentition, with 10.5% having 10 or more teeth affected and 14.6% having hypoplasia, i.e. missing enamel. These findings are in contrast to the 37% with hypoplasia found in a group of third to fifth century Romano-Britons from Dorset, England, suggesting further consideration of possible environmental and genetic differences between the two populations. An overall long-term study of dental development in low birth weight children has shown significantly more (P < 0.001) enamel defects related to major health problems during the neonatal period. By using standardized, reproducible criteria in prevalence studies to gain an overview of the problem and then studying specific groups or conditions, it is possible to identify general and specific factors in the aetiology of enamel defects and investigate further the varying role of genetic and environmental effects.

Enamel defects in primary canines related to traditional treatment of teething problems in Sudan.

In parts of Sudan and some other countries, teething is thought to be the cause of severe health problems in infants, and a traditional treatment involves lancing the alveolar process over the unerupted canines with a heated needle, a procedure known as 'haifat'. Three hundred and ninety-eight children aged 4-8 years were examined for the presence of enamel defects on primary canines, and their parents or guardians were questioned regarding past teething problems and their treatment. Two hundred and fifty-eight (65%) of the children had experienced health problems that had been attributed to teething, and 89 (22%) had been subjected to 'haifat'. 'Haifat' had been practised by all socio-economic groups, but was most prevalent in the lower groups. Enamel defects on the buccal surface of the primary canines were found in 25 (28%) of the children in the 'haifat' group and in 25 (8%) of the other children.

Factors affecting the distribution of enamel hypoplasias within the human permanent dentition.

Frequencies and morphological and chronological distributions of enamel hypoplasias are presented by tooth type (permanent I1 to M2s), based on a sample of 30 prehistoric Amerindians with complete and unworn dentitions. There is nearly a tenfold variation in frequency of defects by tooth, ranging from 0.13 per mandibular second molar to 1.27 per maxillary central incisor. The six anterior teeth average between 0.70 and 1.27 defects/tooth, whereas the eight posterior teeth average between 0.43 and 0.13 defects/tooth. Earlier developing teeth, such as incisors, have earlier peak frequencies of defects (2.0-2.5 years), while later developing teeth, such as second molars, have subsequent peak frequencies (5.0-6.0 years). These variations are relevant when comparing hypoplasia data based on different teeth. Differences in hypoplasia frequencies among teeth are not solely due to variation in time of crown development, as is usually reported. Rather, there is evidence for biological gradients in susceptibility to ameloblastic disruption. Anterior teeth are more hypoplastic than posterior teeth. More developmentally stable "polar" teeth are more hypoplastic than surrounding teeth. Polar teeth may be more susceptible to hypoplasias because their developmental timing is less easily disrupted. In all teeth, hypoplasias are most common in the middle and cervical thirds. Crown development and morphological factors, such as enamel prism length and direction, may influence the development and expression of enamel surface defects.

Distribution of enamel defects and the association with respiratory distress in very low birthweight infants.

Although dental defects have long been observed among surviving pre-term infants, only few systematic studies address this problem. In a clinic limited to recall of infants of very low birthweight (less than 1.5 kg), enamel hypoplasia of primary incisors was found in 14/67 (21%) children, and enamel opacities were found in an additional 31% of the children. In contrast, enamel hypoplasia and opacities were found in 4% and 22%, respectively, of a control group of 46 normal birthweight children. The difference was significant (p less than 0.05) for the hypoplasia but not for the opacities. Primary incisor enamel hypoplasia was more commonly noted in maxillary central incisors than in lateral incisors (X2 = 28.0, p less than 0.01). Furthermore, hypoplasia was more common in maxillary incisors than in mandibular incisors (X2 = 48.4, p less than 0.01). In infants with dental defects, there was no significant correlation with pregnancy risk factors, gestational age, birthweight, septicemia, first-week caloric intake, serum bilirubin, or calcium. Infants with enamel hypoplasia were more likely, however, to have severe respiratory distress syndrome (X2 = 7.2, p less than 0.01), than infants with unaltered enamel. Central incisor edge involvement may indicate post-natal processes and/or a systemic disturbance extending back to the middle trimester of pregnancy.