| 1. |
- Fagrell, Tobias G., et al.
(författare)
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Bacterial invasion of dentinal tubules beneath apparently intact but hypomineralized enamel in molar teeth with molar incisor hypomineralization
- 2008
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Ingår i: International Journal of Paediatric Dentistry. - 0960-7439 .- 1365-263X. ; 18:5, s. 333-340
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: The most common problems for a patient with molar incisor hypomineralization (MIH) are the collapse of enamel and cavitations, loss of fillings, and secondary caries, but most of all, severe hypersensitivity. OBJECTIVE: The aim of this paper was therefore to histologically study possible bacterial invasion of dentinal tubules beneath apparently intact, but hypomineralized enamel in permanent molars with MIH. MATERIAL AND METHODS: Five extracted permanent first molars diagnosed with MIH were fixated, demineralized, and sagittally serially sectioned in a bucco-lingual direction in a microtome with a thickness of 4-5 microm. Sections were stained with a modified Brown and Benn staining for bacteria, unstained sections were analysed in field emission SEM. RESULTS: Stained sections from the cuspal areas, below the hypomineralized enamel, the staining indicated the presence of bacteria in the dentinal tubules. The HTX staining showed that the pulp in sections without any findings was normal and free from bacteria or infiltrates from inflammatory cells. In sections where bacteria were found in the cuspal areas or deeper in the dentin, a zone of reparative dentin was found, and in sections from one tooth, the coronal pulp showed an inflammatory reaction with inflammatory cells. In sections adjacent to those without any bacterial staining, the SEM analyses revealed empty dentinal tubules without any odontoblast processes or signs of bacteria. When odontoblast processes were found, the dentinal tubules were filled with bacteria located on the surface of the odontoblast processes. In some areas, a large number of tubules were found with bacteria. No bacteria were found close to the pulp. The odontoblast processes appeared larger in areas where bacteria were found. CONCLUSIONS: The presence of bacteria in the dentinal tubules and inflammatory reactions in the pulp indicate that oral bacteria may penetrate through the hypomineralized enamel into the dentin, thus possibly contribute to hypersensitivity of teeth with MIH.
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| 2. |
- Fagrell, Tobias G, et al.
(författare)
-
Bacterial invasion of dentinal tubules beneath apparently intact but hypomineralized enamel in molar teeth with molar incisor hypomineralization.
- 2008
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Ingår i: International journal of paediatric dentistry / the British Paedodontic Society [and] the International Association of Dentistry for Children. - : Wiley-Blackwell Publishing Ltd. - 1365-263X .- 0960-7439. ; 18:5, s. 333-40
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: The most common problems for a patient with molar incisor hypomineralization (MIH) are the collapse of enamel and cavitations, loss of fillings, and secondary caries, but most of all, severe hypersensitivity. OBJECTIVE: The aim of this paper was therefore to histologically study possible bacterial invasion of dentinal tubules beneath apparently intact, but hypomineralized enamel in permanent molars with MIH. MATERIAL AND METHODS: Five extracted permanent first molars diagnosed with MIH were fixated, demineralized, and sagittally serially sectioned in a bucco-lingual direction in a microtome with a thickness of 4-5 microm. Sections were stained with a modified Brown and Benn staining for bacteria, unstained sections were analysed in field emission SEM. RESULTS: Stained sections from the cuspal areas, below the hypomineralized enamel, the staining indicated the presence of bacteria in the dentinal tubules. The HTX staining showed that the pulp in sections without any findings was normal and free from bacteria or infiltrates from inflammatory cells. In sections where bacteria were found in the cuspal areas or deeper in the dentin, a zone of reparative dentin was found, and in sections from one tooth, the coronal pulp showed an inflammatory reaction with inflammatory cells. In sections adjacent to those without any bacterial staining, the SEM analyses revealed empty dentinal tubules without any odontoblast processes or signs of bacteria. When odontoblast processes were found, the dentinal tubules were filled with bacteria located on the surface of the odontoblast processes. In some areas, a large number of tubules were found with bacteria. No bacteria were found close to the pulp. The odontoblast processes appeared larger in areas where bacteria were found. CONCLUSIONS: The presence of bacteria in the dentinal tubules and inflammatory reactions in the pulp indicate that oral bacteria may penetrate through the hypomineralized enamel into the dentin, thus possibly contribute to hypersensitivity of teeth with MIH.
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| 3. |
- Fagrell, Tobias G, et al.
(författare)
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Chemical, mechanical and morphological properties of hypomineralized enamel of permanent first molars.
- 2010
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Ingår i: Acta odontologica Scandinavica. - : Informa UK Limited. - 1502-3850 .- 0001-6357. ; 68:4, s. 215-22
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Tidskriftsartikel (refereegranskat)abstract
- The microstructure of hypomineralized enamel in permanent teeth has been described in several studies as less distinct prism sheaths and disorganized enamel with lack of organization of the enamel crystals. The mechanical properties, hardness and modulus of elasticity of the hypomineralized enamel have lower values compared with normal. The aim of this study was to examine normal and hypomineralized enamel using scanning electron microscopy (SEM), hardness measurements and X-ray microanalysis (XRMA).
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| 4. |
- Fagrell, Tobias G, et al.
(författare)
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Effect of ozone treatment on different cariogenic microorganisms in vitro.
- 2008
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Ingår i: Swedish dental journal. - : Swedish Dental Association. - 0347-9994. ; 32:3, s. 139-47
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Tidskriftsartikel (refereegranskat)abstract
- Ozone treatment has been presented and discussed in the literature, as one of the "new" ways to treat dental caries. The aim of this paper was to study the in vitro effect of ozone on some common oral microorganisms related to dental caries using scanning electron microscopy (SEM). The effect of ozone was tested on three different strains of mutans streptococci and one Lactobacillus strain. After exposure of bacteria to ozone treatment for 0 to 60 sec, cultivation on different chair side strips and agar plates took place. Preparation and performance of scanning electron analyses in a field emission scanning electron microscope at 10 kV was then carried out. It was found that gaseous ozone treatment for 20 seconds or more was effective to kill the different microorganisms in vitro. Treatment of 20, 40 and 60 seconds of ozone prevented the bacteria to grow on the different media. Treatment times shorter than 20 seconds resulted in varying results with a limited effect on bacterial growth for treatments of 5-10 sec, respectively. The difference between ozone-treated and untreated specimens was macroscopically readily discernable. None of the strains treated with ozone for 60 seconds showed any bacterial growth. Only samples with untreated bacteria could be found in the SEM analyses in form of large and high colonies. This study presents a clear result of the bactericide effect of ozon (in vitro) on four different strains of bacteria associated with dental caries.
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| 5. |
- Fagrell, Tobias G, et al.
(författare)
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Onset of molar incisor hypomineralization (MIH).
- 2013
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Ingår i: Swedish dental journal. - 0347-9994. ; 37:2, s. 61-70
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Tidskriftsartikel (refereegranskat)abstract
- The etiological factors and timing of the onset of molar incisor hypomineralization (MIH) are still not clear. The aim of this study was to examine ground radial and sagittal sections from teeth diagnosed with MIH using light microscopy, polarized light microscopy and X-ray micro-computed tomography (XMCT) and to estimate the onset and timing of the MIH and to relate the hypomineralized enamel to the incremental lines. Thirteen extracted permanent first molars diagnosed MIH, were analyzed with light microscopy and XMCT. The hypomineralized areas were mainly located in the mesio-buccal cusps, starting at the enamel-dentin-junction and continuing towards the enamel surface. In a relative gray scale analysis the values decreased from the EDJ towards the enamel surface. The findings indicate that the ameloblasts in the hypomineralized enamel are capable of forming an enamel of normal thickness, but with a substantial reduction of their capacity for maturation of enamel. Chronologically, it is estimated that the timing of the disturbance is at a period during the first 6-7 months of age.
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| 6. |
- Fagrell, Tobias G, et al.
(författare)
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Aetiology of severe demarcated enamel opacities--an evaluation based on prospective medical and social data from 17,000 children.
- 2011
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Ingår i: Swedish dental journal. - : Swedish Dental Journal (Sveriges Tandlakarforbund). - 0347-9994. ; 35:2, s. 57-67
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Tidskriftsartikel (refereegranskat)abstract
- During the 1970s dentists reported an increasing prevalence of a "new" type of enamel disturbance.The disturbance was very specific, with areas of demarcated hypomineralised enamel, and was mostly found in permanent first molars and incisors. Several studies have tried to reveal the aetiology behind the enamel disturbance but sofar no clear factors correlated have been found. The aim of the present study was to evaluate aetiological factors to severe demarcated opacities (SDO) in first permanent molars in a large cohort of children enrolled in the "All Babies in Southeast Sweden" (ABIS) project. ABIS is a prospective study of all children in five Swedish counties born between Oct 1, 1997 and Oct 1, 1999, in all about 17,000 children.They have been followed from birth with recording of a large number of factors on nutrition, diseases, medication, infections, social situation etc. With help from 89 Public Dental Service clinics in the same area preliminary examinations of the children, born between Oct 1,1997 and Oct 1,1999, reported 595 children with severe demarcated opacities (SDO) in first molars.These children and a randomly selected age matched group of 1,200 children were further invited to be examined by specialists in paediatric dentistry. At these examinations 224 severe cases were identified as well as 253 children completely without enamel disturbances among children registered in ABIS.These two groups were analysed according to any correlation between SDO and variables in the ABIS databank. The analyses showed no association between SDO and pre-, peri-, and neonatal data. However, we found a positive association between SDO and breastfeeding for more than 6 months (OR 1.9; 95% CI 1.1-3.2), late introduction of gruel (OR 1.9; 95% CI 1.1-2.9), and late introduction of infant formula (OR 1.8; 95% CI 1.2-2.9). A combination of these three variables increased the risk to develop SDO by more than five times (OR 5.1; 95% CI 1.6-15.7). No significant associations were found to other environmental, developmental, or medical factors. We conclude that nutritional conditions during first 6 months of life may influence the risk to develop severe demarcated opacities in first permanent molars.
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| 7. |
- Fagrell, Tobias G
(författare)
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Molar Incisor Hypomineralization
- 2011
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Overall aim: The general objective of this thesis was to enhance the understanding of Molar Incisor Hypomineralization (MIH) in areas of the histological, chemical and mechanical properties of the hypomineralized enamel, objective and subjective clinical symptoms in relation to bacteria findings. Further, to estimate a time for onset of the disturbance and investigate possible etiological factors. Material & Methods: 22 teeth diagnosed with MIH were used in the histological and chemical studies. A number of analytical methods were used; Light microscopy, Polarized light microscopy, Scanning electron microscopy, X-ray microanalysis, Vickers hardness test and X-ray Micro Computed Tomography. Decalcified sections were stained with bacterial staining. An ozone device was tested for the ability to kill strains of oral bacteria. In collaboration with the prospective ABIS study, 17.000 individuals were examined and possible etiological causes of severe demarcated opacities were tested. Results & Conclusions: The hypomineralized enamel was mainly located in the buccal enamel of the teeth and had a high degree of porosity extending from enamel-dentin-junction with a distinct border to the normal cervical enamel. Teeth diagnosed MIH had lower hardness values in hypomineralized enamel and differences in the chemical composition. Bacteria were observed in the enamel and deep into the dentin. Ozone treatment for 20 seconds or more was effective to kill oral microorganisms. Significant relations were found between MIH in first molars and breast feeding more than 6 months, late introduction to gruel and infant formula (later than 6 months). The onset for the hypomineralized enamel was estimated to around 200 days from start of the enamel mineralization.
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