X-ray microanalysis of dentine in primary teeth diagnosed Dentinogenesis Imperfecta type II.

AIM: To analyse the elemental composition of dentine in primary teeth from children diagnosed with Dentinogenesis Imperfecta type II (DI) and from normal sound primary teeth using X-ray microanalysis. MATERIALS AND METHODS: X-ray microanalysis of the elements C, O, Na, Mg, P, Cl, K and Ca were performed in the dentine of five normal primary teeth and in seven primary teeth diagnosed DI. The analysis was made in a low magnification in 10 points from the enamel-dentine junction/root surface toward the pulp. The data was also evaluated with an inductive analysis. RESULTS: Lower values for C were found in DI-dentine compared with normal dentine. Na had significantly higher values in DI-dentine while Mg had significantly lower values. The inductive analysis revealed that Na and Mg were the most important elements for discriminating DI-dentine from normal dentine. CONCLUSIONS: Dentine in primary teeth from patients diagnosed with Dentinogenesis Imperfecta type II analysed with XRMA have lower values of C and Mg and higher values of O and Na compared with normal primary dentine.

Oral health and oral health risk behaviour in children with and without externalising behaviour problems.

AIM: This was to study children with early detected externalising behaviour problems compared to matched controls regarding oral health, oral health risk behaviour and the parental evaluation of the child's oral health and dental care. METHODS: Children aged 10-13 years and with externalising behaviour problems, were compared to matched controls. Behavioural characteristics were based on the Strength and Difficulties Questionnaire. The children and their parents completed questionnaires regarding dental fear, tooth brushing, dietary habits and evaluation of oral health and dental care. Data on dental caries risk assessments, caries, behaviour management problems and dental trauma were obtained from dental files. RESULTS: There were no differences in caries prevalence in children with early detected externalising behaviour problems, compared to controls. However, the former group consumed more sweet drinks when thirsty and brushed their teeth fewer than twice daily; they also had more dental trauma in both dentitions and a higher risk range for dental fear, compared to controls. CONCLUSIONS: This study points out potential oral health risk factors in children with early-detected externalising behaviour problems. Although no difference in caries prevalence was observed, externalising behaviour may affect oral health. Therefore, dental professionals should support the families and the children to preserve dental health by offering increased prophylactic measures. There were no differences between children with externalising behaviour problems, compared with controls, regarding the parent evaluation of their child's dental health. However, more parents in the study group evaluated the dental care as poor or not functioning.

Behavioural characteristics in externalising children with low and elevated risk for dental caries.

AIM: To compare two groups of children with externalising behaviour problems, having low and elevated caries risk, respectively. Those parameters were assessed in relation to behavioural characteristics and family structure, and to compare the caries risk assessment and gender differences in relation to children in general in the Region of Västra Götaland, Sweden. METHODS: Families (228) with children, aged 10-13 years, participating in parent training programmes, were recruited. Parents provided information through questionnaires regarding parental knowledge and monitoring, family warmth and conflict and family structure. Children's behavioural characteristics, based on the Strength and Difficulties Questionnaire and the Disruptive Behaviour Disorder rating scale, were used as outcome. Data about caries risk assessment were obtained from dental records. RESULTS: Children in the elevated caries risk group showed higher mean values for conduct problems as well as impulsivity. Parents of the children in the elevated caries risk group reported more parental solicitation and less family conflicts. Children with an elevated caries risk lived more often in households with more than two children and had more often a father from a non-Nordic country. CONCLUSION: There were statistically significant more children with an elevated caries risk in the study group compared to children in general in the Region of Västra Götaland, both totally and within gender. Differences were observed with regard to behavioural characteristics in externalising children with an elevated risk for caries. Increased knowledge regarding behavioural characteristics in externalising children is an important parameter to be considered in caries risk assessment.

Deviations of inorganic and organic carbon content in hypomineralised enamel.

OBJECTIVES: The purpose of this study was to discriminate hypomineralised enamel of permanent first molars from normal enamel by means of spectroscopic methods. METHODS: The present study was conducted using Multi spot Raman Fourier Transform Spectroscopy, Diffuse Reflectance Infrared Fourier Transform Spectroscopy (FTIR) and X-ray diffraction (XRD). RESULTS: Raman spectroscopy indicated significantly more B-type carbonate and hydrocarbons in hypomineralised enamel diagnosed as MIH (Molar Incisor Hypomineralisation). From XRD analysis, no changes in crystallinity of the enamel apatite could be found. CONCLUSIONS: Using multi spot Raman-spectroscopy, a significant molecular discrimination between normal and hypomineralised enamel could be made. CLINICAL SIGNIFICANCE: Detailed surface studies are needed in order to achieve better restorative materials, specifically designed for restoration of hypomineralised enamel, and are also needed in order to understand and predict the clinical consequences of hypomineralised enamel with the condition MIH.

Slab coupled optical fiber sensor calibration.

This paper presents a method for calibrating slab coupled optical fiber sensors (SCOS). An automated system is presented for selecting the optimal laser wavelength for use in SCOS interrogation. The wavelength calibration technique uses a computer sound card for both the creation of the applied electric field and the signal detection. The method used to determine the ratio between the measured SCOS signal and the applied electric field is also described along with a demonstration of the calibrated SCOS involving measuring the dielectric breakdown of air.

Demineralization of enamel in primary second molars related to properties of the enamel.

Enamel structure is of importance in demineralization. Differences in porosity in enamel effect the rate of demineralization, seen between permanent and deciduous teeth. Individual differences have been shown in the mean mineral concentration values in enamel, the role of this in demineralization is not thoroughly investigated. The aim of this study was to study variations of depths of artificial lesions of demineralization and to analyze the depth in relation to variations in the chemical and mineral composition of the enamel. A demineralized lesion was created in second primary molars from 18 individuals. Depths of lesions were then related to individual chemical content of the enamel. Enamel responded to demineralization with different lesion depths and this was correlated to the chemical composition. The carbon content in sound enamel was shown to be higher where lesions developed deeper. The lesion was deeper when the degree of porosity of the enamel was higher.

Morphological and chemical characterization of tooth enamel exposed to alkaline agents.

OBJECTIVES: In this study, morphological and chemical changes in teeth enamel exposed to alkaline agents, with or without surfactants, have been investigated. In addition, chemical effects of the organic surface layer, i.e. plaque and pellicle, were also investigated. METHODS: The present study was conducted using several techniques: Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and scanning electron microscopy (SEM). RESULTS: From XPS-measurements, it was found that exposure to alkaline solutions resulted in a massive removal of carbon from the tooth surface, and that the addition of surfactants increased the rate under present conditions. Based on the results from the FTIR-analysis, no substitution reactions between phosphate, carbonate and hydroxide ions in the enamel apatite could be detected. From a minor SEM-analysis, degradation and loss of substance of the enamel surface was found for the exposed samples. From XRD-analysis, no changes in crystallinity of the enamel apatite could be found between the samples. CONCLUSIONS: The findings in this study show that exposure to alkaline solutions results in a degradation of enamel surfaces very dissimilar from acidic erosion. No significant erosion or chemical substitution of the apatite crystals themselves could be discerned. However, significant loss of organic carbon at the enamel surface was found in all exposed samples. The degradation of the protective organic layer at the enamel surface may profoundly increase the risk for caries and dental erosion from acidic foods and beverages.

Scanning electron micrograph analysis of hypomineralized enamel in permanent first molars.

UNLABELLED: First molars with cream- to yellow-coloured demarcated opacities of the enamel, often in combination with severe loss of substance, are common in many child populations. The aetiology is obscure. AIM AND METHOD: The aim of this study was to study the ultrastructure of the enamel of 10 affected teeth by means of scanning electron microscopy (SEM) in order to gain a better understanding of the clinical appearance and treatment problems of this condition, and to find some clues to its aetiology. RESULTS: The basic enamel structure with enamel rods and interrod zones was found in porous parts of the enamel, as well as in normal parts, but the packing of the hydroxylapatite crystals seemed to be looser and less well organized in the porous parts. The border between normal and hypomineralized enamel was usually distinct, and followed the direction of the rods. The preserved basic structure indicates normal function of the ameloblasts during their secretion phase, but impaired function during their maturation stage. CONCLUSION: Considering the poor etch profile, it seems reasonable to recommend removal of all affected enamel surrounding the cavity, if possible, and to use a glass ionomer filling with its chemical bonding to tooth substrate, when restoring first molars with remaining affected enamel.

Oral manifestations in 22q11 deletion syndrome.

OBJECTIVES: The aims of this study were to investigate and describe oral manifestations in 22q11 deletion syndrome, and to relate the findings to medical conditions. DESIGN: Cross-sectional. SAMPLE AND METHODS: Fifty-three consecutive patients from Sweden referred to the Sahlgrenska University Hospital during a 3-year period were included, median age 8 yrs (range 2-43; mean age 11.09). All but six patients were children 3-19-years-old. The patients were examined concerning oral mucosa, dental anomalies, dental caries, occlusal development, and eruption of the teeth. The clinical findings were compared to medical data and case history. RESULTS: Dental anomalies were registered in high numbers. Enamel hypoplasia was found in 16 patients. In 13 cases this was documented in primary teeth, of which 10 patients had symmetrical and chronological defects. Enamel hypomineralization was found in 23 patients and was equally common in both primary and permanent teeth. The use of computerized inductive analyses revealed that enamel hypoplasia was associated with medical conditions like preterm birth and congenital heart malformation while hypomineralization was associated with more diffuse conditions like frequent infections. Hypodontia was registered in seven patients, while eight had aberrant tooth shape, and nine patients presented delayed tooth eruption. The patients had an average of 4.6 carious or filled teeth and the oral health was assessed as impaired in 15 patients who had severe dental caries (5-18 carious teeth or multiple active incipient caries lesions). CONCLUSIONS: In 22q11 deletion syndrome the oral cavity is affected by anomalies in dental enamel, tooth shape, numbers of teeth, and eruption. Dental health problems due to caries are common. This is of special importance as patients with 22q11 deletion syndrome frequently present with congenital heart malformations and immunological problems.

The prevalence of demarcated opacities in permanent first molars in a group of Swedish children.

The permanent teeth of 516 7- and 8-year-old Swedish children from a low-fluoride area were examined for developmental enamel defects. Special attention was paid to demarcated opacities in permanent first molars and permanent incisors (MIH). The examination was done in their schools, using a portable light, a mirror, and a probe. The modified DDE index of 1992 was used for recording the enamel defects, supplemented with a further classification into severe, moderate, and mild defects. Demarcated opacities in permanent first molars were present in 18.4% of the children. The mean number of hypomineralized teeth of the affected children was 3.2 (standard deviation, 1.8), of which 2.4 were first molars. Of the children 6.5% had severe defects, 5% had moderate defects, whereas 7% had only mildly hypomineralized teeth. In conclusion, hypomineralized first molars appeared to be common and require considerable treatment in the Swedish child population.

Etiologic factors influencing the prevalence of demarcated opacities in permanent first molars in a group of Swedish children.

The aim of this study was to determine possible etiological factors for a developmental enamel defect, i.e. demarcated opacities, affecting the permanent first molars. A questionnaire about possible etiological factors of enamel developmental defects was filled in by the parents of 8-yr-old children (n=516) prior to a dental examination of permanent teeth. Demarcated opacities of permanent first molars had been found in 18.4% of the children in a previous study of these children. Fifteen % had more than one tooth affected indicating systemic causation. Questions were asked about mother's health and medication during pregnancy, birth complications, health and medication of the child during the first 3 yr of life, breast-feeding, heredity, and fluoride supplements. The affected children, especially the boys, were reported to have had more health problems, in particular asthma (but only 4 cases), during the first year of life. Use of antibiotics was also more common among the affected children, but owing to a strong co-variance with health problems these factors could not be separated. Breast-feeding history was similar in children with and without enamel defects. The etiology of hypomineralized first molars is not yet fully understood, but based on the results of this retrospective study, health problems in infancy, especially respiratory diseases, seem to be involved.

Knowledge-based system for structured examination, diagnosis and therapy in treatment of traumatised teeth.

Dental trauma in children and adolescents is a common problem, and the prevalence of these injuries has increased in the last 10-20 years. A dental injury should always be considered an emergency and, thus, be treated immediately to relieve pain, facilitate reduction of displaced teeth, reconstruct lost hard tissue, and improve prognosis. Rational therapy depends upon a correct diagnosis, which can be achieved with the aid of various examination techniques. It must be understood that an incomplete examination can lead to inaccurate diagnosis and less successful treatment. Good knowledge of traumatology and models of treatments can also reduce stress and anxiety for both the patient and the dental team. Knowledge-based Systems (KBS) are a practical implementation of Artificial Intelligence. In complex domains which humans find difficult to understand, KBS can assist in making decisions and can also add knowledge. The aim of this paper is to describe the structure of a knowledge-based system for structured examination, diagnosis and therapy for traumatised primary and permanent teeth. A commercially available program was used as developmental tool for the programming (XpertRule, Attar, London, UK). The paper presents a model for a computerised decision support system for traumatology.

Analysis of caries status development in relation to socio-economic variables using a case-based system.

The aim of this study was to detect, using case-based reasoning (CBR) induction methods in time series analysis, how measurable socio-economical adjustments were related to the caries status development. The study concerned the year classes leaving the organised dental care for the time period 1987-95, and had received dental care at the Public Dental Service of Göteborg. The results, as presented by a caries incidence index, indicated that at least one socioeconomical factor, individuals seeking employment, was of importance for the caries status development, a factor with an increase of considerable proportions since 1990. The findings indicated that the other socio-economic variables used did not have the same importance for the caries status development. One feasible explanation is that these factors reflect more upon the social family situation than the economical. If the caries status reflects the social situation of the individual more than the economical, this argument will elucidate the reasoning. Using CBR for the analysis of relationships between oral disease and parameters possibly influencing health development has proven to be a valuable tool and complement to more traditional statistical methods. The analysis can make relationships explicit through the hierarchic knowledge trees and also show redundant information, attributes not appearing in the trees.

Effects of compensation method on physician behaviors.

OBJECTIVE: To examine physician and leader perceptions of the relationship between physician compensation and the productivity of physicians practicing in medical groups. STUDY DESIGN: Key informant interviews identified subjects' perceptions of factors influencing physician productivity and the behavioral effects of individual financial incentives. Interview transcripts were analyzed by a team of physicians, economists, and other researchers. STUDY POPULATION: Physicians, medical leaders, and group practice administrators (n = 114) representing 46 medical group practices in California, Oregon, Washington, and Wisconsin were interviewed. RESULTS: Five major themes emerged: (1) Most physicians reported that financial incentives did not substantially affect their own behavior, except for productivity. However, they suggested that specific compensation models do lead to certain seemingly undesirable physician behaviors. (2) By contrast, medical group leaders reported that financial incentives do affect a variety of physician behaviors. (3) Four productivity drivers emerged: financial incentives, demand-side factors, systems and infrastructure, and other individual or group attributes. (4) Physician compensation systems are evolving toward a blend of production-based and production-neutral incentives, plus new metrics aligned with the demands of managed care. (5) Culture, size, and specialty mix are significant determinants of group physician compensation systems. CONCLUSIONS: Compensation method is perceived to be a significant influence on physician productivity, particularly among group practice leaders. The changing context of medical practice represents another powerful "macro" lever on physician behavior.

Secondary ion mass spectrometry and X-ray microanalysis of hypomineralized enamel in human permanent first molars.

A common finding in Swedish children is hypomineralization in first molars of unknown cause. Little is known about the chemical composition of the disturbed enamel. The aim here was to analyse the concentration gradients for F, Cl, Na, Mg, K and Sr in hypomineralized enamel from 17 permanent molars by means of secondary ion mass spectrometry, to complete this analysis with an examination of the main matrix elements O, P and Ca by means of X-ray microanalysis, and to compare them with normal enamel. Hypomineralized enamel had a higher content of carbon and the calcium as well as the phosphorus concentration was lower than in normal enamel. The mean Ca/P ratio in hypomineralized areas was significantly lower (1.4) than in the adjacent normal enamel (1.8). The F content was highly variable in impaired enamel and higher than in normal, but close to the surface there was most often no difference between the two. Contents of Mg and K were slightly higher in hypomineralized areas, especially towards the surface. Also Na had a somewhat higher content toward the surface in defective enamel. Cl and Sr contents had negligible or no diversity in relation to the degree of mineralization.

Personal sampling in parallel with open-face filter cassettes and IOM samplers for inhalable dust--implications for occupational exposure limits.

Parallel personal sampling was carried out with the open-face filter cassette and the IOM sampler for inhalable dust for nine types of organic dust. Parallel samples numbering 749 were obtained from 152 plants. Extremely large values and outliers were disregarded, and the remaining data for each type of dust were divided into subsets according to type of product or work task, and analyzed with the aid of linear regression. The coefficient of regression for each subset ranged between 0.2 and 0.7. Hypothetical occupational exposure limits (OELs) for inhalable dust were calculated based on the linear relation obtained between the dust concentrations measured with the open-face filter cassette and the IOM sampler. The fraction of person days with time-weighted average (TWA) concentrations exceeding the calculated hypothetical OELs for inhalable dust was obtained from the distribution of measured TWA inhalable dust concentrations. Based on the results of this study and the difference in sampling efficiency for large particles between the two samplers, it was concluded that the numerical value of the OEL for inhalable dust may be set at approximately twice the numerical value of the corresponding limit value for "total dust." Additional consideration of recently discovered health effects, and technical and economical factors may result in other numerical values of future OELs for inhalable dust.

Long-term prognosis of crown-fractured permanent incisors. The effect of stage of root development and associated luxation injury.

OBJECTIVES: The aim of the present study was to investigate pulp healing responses following crown fracture with and without pulp exposure as well as with and without associated luxation injury and in relation to stage of root development. PATIENT MATERIAL AND METHODS: The long-term prognosis was examined for 455 permanent teeth with crown fractures, 352 (246 with associated luxation injury) without pulpal involvement and 103 (69 with associated luxation injury) with pulp exposures. Initial treatment for all patients was provided by on-call oral surgeons at the emergency service, University Hospital (Rigshospitalet), Copenhagen. In fractures without pulpal involvement, dentin was covered by a hard-setting calcium hydroxide cement (Dycal), marginal enamel acid-etched (phosphoric acid gel), then covered with a temporary crown and bridge material. In the case of pulp exposure, pulp capping or partial pulpotomy was performed. Thereafter treatment was identical to the first group. Patients were then referred to their own dentist for resin composite restoration. RESULTS: Patients were monitored for normal pulp healing or healing complications for up to 17 years after injury (x = 2.3 years, range 0.2-17.0 years, SD + 2.7). Pulp healing was registered and classified into pulp survival with no radiographic change (PS), pulp canal obliteration (PCO) and pulp necrosis (PN). Healing was related to the following clinical factors: stage of root development at the time of injury, associated damage to the periodontium at time of injury (luxation) and time interval from injury until initial treatment. Crown fractures with or without pulp exposure and no concomitant luxation injury showed PS in 99%, PCO in 1% and PN in 0%. Crown fractures with concomitant luxation showed PS in 70%, PCO in 5% and PN in 25%. An associated damage to the periodontal ligament significantly increased the likelihood of pulp necrosis from 0% to 28% (P < 0.001) in teeth with only enamel and dentin exposure and from 0% to 14% (P < 0.001) in teeth with pulp exposure. CONCLUSIONS: In the case of concomitant luxation injuries, the stage of root development played an important role in the risk of pulp necrosis after crown fracture. However, the primary factor related to pulp healing events after crown fracture appears to be compromised pulp circulation due to concomitant luxation injuries.

Enamel hypomineralization of permanent first molars: a morphological study and survey of possible aetiological factors.

OBJECTIVES: The aim of this study was to investigate the morphological appearance of severe hypomineralized enamel of permanent first molars by means of polarized light microscopy, and to estimate the possible time, severity and longevity of the insult. Furthermore, the aim was to survey some commonly implicated aetiological factors in order to gain knowledge about possible pathogenesis of the enamel disturbances which could be compared with future epidemiological studies. SAMPLE AND METHODS: Seventy-three teeth, which had been extracted due to severe hypomineralizations of the enamel, were collected and serially cut longitudinally in a bucco-lingual direction. The sections were examined in polarized light, dry and embedded in water. The children were also examined with respect to the demarcated opacities of other permanent teeth than those that were extracted. The parents were asked about their health during the mother's pregnancy, the time of gestation, birth weight and any complications. They were also asked about the child's health during the first 2 years of its life, the length of time of breast-feeding and also about fluoride supplements. RESULTS: The hypomineralized areas extended cervically from the cusps, comprising about half of the buccal and lingual sides. The cervical borders to normal enamel were well defined and mainly followed the lines of Hunter-Schreger. The hypomineralized zones were covered by thin well-mineralized enamel. The majority of the children had demarcated opacities of all their first molars and also of some permanent incisors. No obvious correlation to the anamnestic data could be found. CONCLUSIONS: The hypomineralized enamel in the investigated teeth demonstrated areas of porosity of varying degrees. The yellow/brown defects were more porous than the white-cream and extended through the whole enamel layer, while the white-cream opacities were situated in the inner parts of the enamel. There had probably been an interacting disturbance of short duration of systemic origin of the activity of the ameloblast during the first 2 years of the child's life, resulting in chronological dispersed hypomineralized demarcated opacities in the developing teeth.

Evaluation of three years of dental care of adolescents in the Public Dental Service in west Sweden.

107 individuals, randomly selected from the County of Göteborg and Bohuslän, all born in 1970 were followed regarding the dental care received 1987-1989. The records of each individual from the actual time were collected and information on diagnosis and treatment measures was gathered. Radiographs from the actual time were studied by one of the authors. Sixty-two per cent of the adolescents had been examined and treated all 3 years. Six percent had not been seen at all. The sample was divided into three groups depending on the patient's DFSa value at the examination the first year. This classification appeared to correlate well with caries development in the following years. One-fourth of the sample was responsible for the major part of the non-attendance and late cancellations. The dental health of these subjects was below average, and non-attendance seemed to be a further risk factor. The preventive measures undertaken during the study appeared to correlate poorly with the actual situation of the patient and the presence or absence of potential risk factors.

Machine learning methods applied on dental fear and behavior management problems in children.

The etiologies of dental fear and dental behavior management problems in children were investigated in a database of information on 2,257 Swedish children 4-6 and 9-11 years old. The analyses were performed using computerized inductive techniques within the field of artificial intelligence. The database held information regarding dental fear levels and behavior management problems, which were defined as outcomes, i.e. dependent variables. The attributes, i.e. independent variables, included data on dental health and dental treatments, information about parental dental fear, general anxiety, socioeconomic variables, etc. The data contained both numerical and discrete variables. The analyses were performed using an inductive analysis program (XpertRule Analyser, Attar Software Ltd, Lancashire, UK) that presents the results in a hierarchic diagram called a knowledge tree. The importance of the different attributes is represented by their position in this diagram. The results show that inductive methods are well suited for analyzing multifactorial and complex relationships in large data sets, and are thus a useful complement to multivariate statistical techniques. The knowledge trees for the two outcomes, dental fear and behavior management problems, were very different from each other, suggesting that the two phenomena are not equivalent. Dental fear was found to be more related to non-dental variables, whereas dental behavior management problems seemed connected to dental variables.