Determination of the accuracy of implant reconstruction and dose delivery in brachytherapy in The Netherlands and Belgium

Purpose: To gain insight into the accuracy of brachytherapy treatments, the accuracy of implant reconstruction and dose delivery was investigated in 33 radiotherapy institutions in The Netherlands and Belgium. Materials and methods: The accuracy of the implant reconstruction method was determined using a cubic phantom containing 25 spheres at well-known positions. Reconstruction measurements were obtained on 41 brachytherapy localizers, 33 of which were simulators. The reconstructed distances between the spheres were compared with the true distances. The accuracy of the dose delivery was determined for high dose rate (HDR), pulsed dose rate (PDR) and low dose rate (LDR) afterloading systems using a polymethyl methacrylate cylindrical phantom containing a NE 2571 ionization chamber in its centre. The institutions were asked to deliver a prescribed dose at the centre of the phantom. The measured dose was compared with the prescribed dose. Results: The average reconstruction accuracy was -0.07 mm (±0.4 mm, 1 SD) for 41 localizers. The average deviation of the measured dose from the prescribed dose was +0.9% (±1.3%, 1 SD) for 21 HDR afterloading systems, +1.0% (±2.3%, 1 SD) for 12 PDR afterloaders, and +1.8% (±2.5%, 1 SD) for 15 LDR afterloaders. Conclusions: This comparison showed a good accuracy of brachytherapy implant reconstruction and dose delivery in The Netherlands and Belgium

Foetal, neonatal and child vitamin D status and enamel hypomineralization

Objectives: Recent literature suggested that higher vitamin D concentrations in childhood are associated with a lower prevalence of molar incisor hypomineralization (MIH). As tooth development already starts in utero, we aimed to study whether vitamin D status during foetal, postnatal and childhood periods is associated with the presence of hypomineralized second primary molars (HSPMs) and/or MIH at the age of six. Methods: Our study was embedded in the Generation R Study, a population-based, prospective cohort from foetal life onwards in Rotterdam, the Netherlands. HSPMs and MIH were scored from intraoral photographs of the children at their age of six. Serum 25(OH)D concentrations were measured at three points in time, which resulted in three different samples; mid-gestational in mothers' blood (n = 4750), in umbilical cord blood (n = 3406) and in children's blood at the age of 6 years (n = 3983). Results: The children had a mean (±SD) age of 6.2 (±0.5) years at the moment of taking the intraoral photographs. After adjustment for confounders, no association was found between foetal 25(OH)D concentrations and the presence of HSPMs (OR 1.02 per 10 nmol/L higher 25(OH)D, 95% CI: 0.98-1.07) or MIH (OR 1.05 per 10 nmol/L increase, 95% CI: 0.98-1.12) in 6-year-olds. A higher 25(OH)D concentration in umbilical cord blood resulted in neither lower odds of having HSPM (OR 1.05, 95% CI: 0.98-1.13) nor lower odds of having MIH (OR 0.95, 95% CI: 0.84-1.07) by the age of six. Finally, we did not find higher 25(OH)D concentrations at the age of six to be associated with a significant change in the odds of having HSPM (OR 0.97, 95% CI: 0.92-1.02) or MIH (OR 1.07, 95% CI: 0.98-1.16). Conclusions: 25(OH)D concentrations in prenatal, early postnatal and later postnatal life are not associated with the presence of HPSMs or wi

Deciduous molar hypomineralisation, its nature and nurture

Vijf tot negen procent van de Nederlandse kinderen heeft kaaskiezen in het melkgebit, blijkt uit onderzoek van Marlies Elfrink. Kaaskiezen ontstaan door een stoornis in het in het mineraalgehalte van het tandglazuur. De kiezen hebben de kleur van kaas en zijn gevoeliger dan andere kiezen, omdat de buitenste laag zwakker is. Elfrink toont aan dat kinderen met kaaskiezen meer gaatjes hebben dan leeftijdsgenoten zonder kaaskiezen. Ook hebben deze kinderen een grotere kans op kaaskiezen in het blijvende gebit dan leeftijdgenoten met gezonde kiezen. Aan de hand van de onderzoeksresultaten kunnen behandelplannen voor kinderen met kaaskiezen worden verbeterd. Omdat deze kinderen meer kans hebben op blijvende kaaskiezen, is extra aandacht van de tandarts nodig op het moment dat de eerste blijvende kiezen doorkomen

Molaren Inzisiven Hypomineralisation und Milchmolaren Hypomineralisation - klinisches Erscheinungsbild, Prävalenz und deren Ursachen - Molar Incisor Hypomineralisation and Deciduous Molar Hypomineralisation - clinical appearance, prevalence and determinants for its occurrence

Background: Molar Incisor Hypomineralisation (MIH) and Deciduous Molar Hypomineralisation (DMH) are frequently occurring dental problems in children. Children with MIH have demarcated opacities in their erupting first permanent molars often in combination with demarcated opacities in their permanent incisors. Children with DMH have comparable demarcated opacities in their second primary molars. The hypomineralised enamel contains less mineral, often resulting in an easy post eruptive enamel loss with rapid caries progression. Results: The prevalence of MIH and DMH varies between birth-years and countries and even between cities. The most recent prevalence of MIH in Germany is 9.9 %, the prevalence of DMH has not been described yet in Germany. The aetiology of MIH and DMH is still unclear. Many possible determinants have been described in literature. The determinants for DMH can be found earlier in life than the determinants for MIH, but they show overlap. This can be related to the dental development. Children with DMH have an increased risk of having MIH. Conclusion: Early diagnosis of DMH and MIH is important, so extra attention can be paid to these children by dentists and their team in the period of eruption of the second primary molars and first permanent molars

Hypomineralized second primary molars: Prevalence data in Dutch 5-year-olds

The aim of this cross-sectional observational study was to report on the prevalence of hypomineralizations in second primary molars in 5-year-old Dutch children. In the study 386 (45% girls) 5-year-old Dutch children, all insured by a Health Insurance Fund, participated. Scoring criteria for molar incisor hypomineralization molars were adapted to score second primary molars. The prevalence of hypomineralized second primary molars (HSPM) was 4.9% at child level and 3.6% at tooth level. Most HSPMs (87%) showed demarcated opacities, followed by posteruptive enamel loss (40%). Copyright © 2008 S. Karger AG