| 1. |
- Farzad, Payam, 1973, et al.
(författare)
-
Integration of dental implants in conjunction with edta-conditioned dentin grafts: An experimental study
- 2021
-
Ingår i: Dentistry Journal. - : MDPI AG. - 2304-6767. ; 9:6
-
Tidskriftsartikel (refereegranskat)abstract
- This study was undertaken to investigate the integration of titanium micro-implants installed in conjunction with previously dentin-grafted areas and to study the morphological appearance, mineral content, and healing pattern of xenogenic EDTA-conditioned dentin blocks and granules grafted to cavities in the tibial bone of rabbits. Demineralized and non-demineralized dentin blocks and granules from human premolars were implanted into cavities prepared on the lateral aspects of the tibias of rabbits. After a healing period of six months, micro-implants were installed at each surgical site. Histological examinations were carried out after 24 weeks. Characterization of the EDTA-conditioned dentin blocks was performed by means of light microscopy, dental X-rays, scanning electron microscopy, and energy dispersive X-ray analysis (EDX). No implants were found to be integrated in direct contact with the dentin particles or blocks. On the EDTA-conditioned dentin surface, the organic marker elements C and N dominated, as revealed by EDX. The hydroxyapatite constituents Ca and P were almost absent on the dentin surface. No statistically significant difference was observed between the EDTA-conditioned and non-demineralized dentin, as revealed by BIC and BA. The bone-inductive capacity of the dentin material seemed limited, although demineralization by means of EDTA indicated higher BIC and BA values in conjunction with the installed implants in the area. A 12 h EDTA treatment did not fully decalcify the grafts, as revealed by X-ray analysis. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.
|
|
| 2. |
- Larsson, Dennis, et al.
(författare)
-
Antagonistic effects of 24R,25-dihydroxyvitamin D3 and 25-hydroxyvitamin D3 on L-type Ca2+ channels and Na+/Ca2+ exchange in enterocytes from Atlantic cod (Gadus morhua).
- 2002
-
Ingår i: Journal of Molecular Endocrinology. - : Bioscientifica. - 0952-5041 .- 1479-6813. ; 28:1, s. 53-68
-
Tidskriftsartikel (refereegranskat)abstract
- There is mounting evidence that vitamin D and its metabolites play important roles in regulating plasma calcium concentrations in teleost fish as in other vertebrates. The aims of the present study were to elucidate the possible cellular target mechanisms for the rapid actions of 24R,25(OH)(2)D(3), 25(OH)D(3) and 1,25(OH)(2)D(3) in Atlantic cod enterocytes at physiological doses, and to establish the concentration and thus the physiological range of circulating 24R,25(OH)(2)D(3), 25(OH)D(3) and 1,25(OH)(2)D(3) in the Atlantic cod. The plasma concentrations of 25(OH)D(3), 1,25(OH)(2)D(3) and 24R,25(OH)(2)D(3) were 15.3 +/- 2.7nM, 125.1 +/- 12.3pM and 10.1 +/- 23.5nM respectively. Exposure of enterocytes to 10mM calcium (Ca(2+)) evoked an increase in intracellular Ca(2+) concentrations ([Ca(2+)](i)). This increase was suppressed by 24R,25(OH)(2)D(3) dose-dependently, with an EC(50) of 4.9nM and a maximal inhibition of 60%. 24R,25(OH)(2)D(3) (20nM) abolished an increase in [Ca(2+)](i) (approximately 252%) in the control enterocytes exposed to 10microM S(-)-BAYK-8644, suggesting that the hormone acts by inhibiting Ca(2+) entry through L-type voltage-gated Ca(2+) channels. Administration of 20nM 24R,25(OH)(2)D(3) to enterocytes in the absence of extracellular Ca(2+) increased [Ca(2+)](i) by approximately 20%, indicating a release of Ca(2+) from intracellular stores. Administration of 25(OH)D(3) (20nM) resulted in a biphasic change in the enterocyte [Ca(2+)](i): within 1--5s, it decreased to 87 +/- 12nM below its mean basal [Ca(2+)](i) (334 +/- 13nM), followed by a rapid recovery of [Ca(2+)](i) to a new level, 10% lower than the initial [Ca(2+)](i). The rapid decrease, the recovery rate and the final [Ca(2+)](i) were all affected dose-dependently by 25(OH)D(3), with EC(50) values of 8.5, 17.0 and 18.9nM respectively. Furthermore, the effects of 25(OH)D(3) were sensitive to sodium (Na(+)), bepridil (10microM) and nifedipine (5 microM), suggesting that 25(OH)D(3) regulates the activity of both basolateral membrane-associated Na(+)/Ca(2+) exchangers and brush border membrane-associated L-type Ca(2+) channels. Administration of 25(OH)D(3) (10nM) to enterocytes in the absence of extracellular Ca(2+) increased [Ca(2+)](i) by approximately 18%, indicating a release of Ca(2+) from intracellular stores. 1,25(OH)(2)D(3) also affected enterocyte [Ca(2+)](i) in a biphasic manner: the rapid decrease, the recovery rate, and the mean final [Ca(2+)](i) were all affected dose-dependently, with EC(50) values of 8.3, 24.5 and 7.7nM respectively. The high EC(50) values for 1,25(OH)(2)D(3) compared with circulating concentrations of 1,25(OH)(2)D(3) (130pM) suggest that this effect is pharmacological, rather than of physiological relevance in enterocyte Ca(2+) homeostasis of the Atlantic cod. It is concluded that 24R,25(OH)(2)D(3) has a physiological role in decreasing intestinal Ca(2+) uptake via inactivation of L-type Ca(2+) channels, whereas the physiological role of 25(OH)D(3) is to increase enterocyte Ca(2+) transport via activation of Na(+)/Ca(2+) exchangers, concurrent with activation of L-type Ca(2+) channels.
|
|
| 3. |
- Lundquist, Patrik, 1969, et al.
(författare)
-
Na+/Ca2+ exchanger isoforms of rat odontoblasts and osteoblasts.
- 2000
-
Ingår i: Calcified Tissue International. - 0171-967X. ; 67:1, s. 60-7
-
Tidskriftsartikel (refereegranskat)abstract
- In odontoblasts as well as osteoblasts, a number of mechanisms for the inflow and extrusion of Ca2+ have been demonstrated. The entrance of Ca2+ ions into odontoblasts occurs mainly through voltage-gated calcium channels. Extrusion of Ca2+ is found to be an ATP-dependent process and, in addition, Na+/Ca2+-antiports exist, which are provoked by extracellular Na+. The aim of this study was to identify the Na+/Ca2+-antiport isoforms expressed in dentinogenically active rat incisor odontoblasts and to make a comparison with different osteoblastic cells. Using RT-PCR and RNAse protection assay, we demonstrated the expression of three different isoforms, NaCa 3, 7, and 10, of the NCX1-encoded antiport in odontoblasts and osteoblastic cells. When incubated in the presence of Na+, dissected rat incisor odontoblasts as well as the osteoblastic cells extruded Ca2+ ions, as detected by chlorotetracycline and Fura-2 fluorometry, thus supporting a physiological role for the detected isoform expression. Odontoblasts and rat calvarial osteoblasts, as well as osteoblast-like cell lines UMR-106.01 and Saos-2, were shown to exhibit identical phenotypes of Na+/Ca2+-antiport isoform expression, different from the expression patterns of other tissues. The significance of this specific expression pattern is unknown, but there is a possibility that it is in some way related to the unique demands on these cell types to produce mineralized connective tissue.
|
|
| 4. |
- Örtengren, Ulf, 1959, et al.
(författare)
-
Influence of pH and time on organic substance release from a model dental composite: a fluorescence spectrophotometry and gas chromatography/mass spectrometry analysis.
- 2004
-
Ingår i: European journal of oral sciences. - : Wiley. - 0909-8836 .- 1600-0722. ; 112:6, s. 530-7
-
Tidskriftsartikel (refereegranskat)abstract
- In this study we assessed the influence of pH and time on the degradation and elution of organic substances from the composite resin material, Z-100. To accomplish this, fluorescence spectrophotometry was evaluated as an appropriate technique for the identification of six organic substances (methacrylic acid, methyl methacrylate, hydroquinone, ethylene glycol dimethacrylate, triethylene glycol dimethacrylate and 4,4'-isopropylidenediphenol) that were eluted from resin composite material stored for 24 h or 6 months at pH 4.0, 6.0 or 8.0. In addition, complementary analyses (solid-phase microextraction/gas chromatography/mass spectrometry) were carried out to identify and quantify the substances. The main substances leached from the resin composite were methacrylic acid, triethylene glycol dimethacrylate and hydroquinone. It was concluded that fluorescence spectrophotometry seems to be a suitable, non-destructive technique for the qualitative analysis of eluted organic components. Critical combinations of time and pH allowed the elution of several organic substances, predominantly methacrylic acid, triethylene glycol dimethacrylate and hydroquinone, from the model resin composite, Z-100.
|
|
| 5. |
- Alamadi, E., et al.
(författare)
-
A comparative study of cone beam computed tomography and conventional radiography in diagnosing the extent of root resorptions
- 2017
-
Ingår i: Progress in Orthodontics. - : Springer Science and Business Media LLC. - 2196-1042. ; 18, s. 1-8
-
Tidskriftsartikel (refereegranskat)abstract
- Root resorptions are assessed and diagnosed using different radiographical techniques. A comparison of the ability to assess resorptions on two-dimensional (2D) and three-dimensional (3D) radiographs is, hitherto, lacking. The aims of this study were to evaluate the accuracy of 2D (periapical radiographs, PA and panoramic radiograph, PAN) and 3D (cone beam computed tomography, CBCT) radiographic techniques in measuring slanted root resorptions compared to the true resorptions, a histological gold standard, in addition to a comparison of all the radiographic techniques to each other. Radiographs (CBCT, PA, and PAN), in addition to histological sections, of extracted deciduous canines from thirty-four patients were analyzed. Linear measurements of the most and least resorbed side of the root, i.e., "slanted" resorptions, were measured using an analyzing software (Facad A (R)). For classification of slanted root resorptions, a modified Malmgren index was used. PAN underestimated the root length on both the least and most resorbed side. Small resorptions, i.e., low modified Malmgren scores, were more difficult to record and were only assessed accurately using CBCT. The root resorption scores were underestimated using PA and PAN. In assessment of linear measures, PAN differed significantly from both CBCT and PA. CBCT is the most accurate technique when measuring and scoring slanted root resorptions.
|
|
| 6. |
- Almosa, N. A., et al.
(författare)
-
Caries risk profiles in orthodontic patients: A 4-year follow-up study using the Cariogram model in governmental vs. private clinics
- 2018
-
Ingår i: Saudi Dental Journal. - : Elsevier BV. - 1013-9052. ; 30:2, s. 166-174
-
Tidskriftsartikel (refereegranskat)abstract
- Objectives: To (1) analyze caries-related factors and (2) evaluate caries risk using the Cariogram model for governmental and private orthodontic patients at de-bonding and 4 years after de-bonding. Materials and methods: Forty orthodontic patients with mean age of 26.4 years were recruited from a governmental (G) group (n = 20) and private (P) group (n = 20) and were examined at de-bonding (T1) and 4 years after de-bonding (T2). The examination included a questionnaire, plaque scoring, caries examination, bitewing radiographs, and assessment of salivary secretion rate, buffering capacity and cariogenic microorganisms. The data were entered into the Cariogram program to illustrate the caries risk profiles. Results: The chance to avoid new cavities was higher in P-group compared to G-group at T1 (58% and 31%, respectively) (P < 0.01) and T2 (77% and 52%, respectively) (P < 0.001). Plaque index was significantly higher in G-group, and fluoride was used significantly more in P-group at T1 and T2 (P < 0.05). The chance to avoid new cavities was higher at T2 compared to T1 (64% and 44%, respectively) (P < 0.001). Saliva secretion rate and buffer capacity were significantly increased, and the plaque index was significantly decreased at T2 compared to T1 (P < 0.01). Conclusion: According to the Cariogram, orthodontic patients were less likely to avoid new cavities at de-bonding and 4 years after de-bonding in government clinics compared to private clinics, and the caries risk significantly decreased 4 years after orthodontic treatment for all patients, regardless of the location of treatment. (C) 2018 The Authors. Production and hosting by Elsevier B.V. on behalf of King Saud University.
|
|
| 7. |
- Almosa, Naif Abdullah, 1981, et al.
(författare)
-
Diagnosing the severity of buccal caries lesions in governmental and private orthodontic patients at debonding, using the ICDAS-II and the DIAGNOdent Pen.
- 2014
-
Ingår i: The Angle orthodontist. - : The Angle Orthodontist (EH Angle Education & Research Foundation). - 1945-7103 .- 0003-3219. ; 84:3, s. 430-436
-
Tidskriftsartikel (refereegranskat)abstract
- Abstract Objectives: To clinically evaluate the prevalence of buccal caries and white spot lesions (WSLs) at debonding in governmental and private orthodontic patients, using the International Caries Detection and Assessment System (ICDAS-II) and the DIAGNOdent Pen, and to study the correlation between the two methods. Materials and Methods: A cross-sectional study was carried out on the nonextracted premolars and anterior teeth of 89 orthodontic patients. They were recruited into two groups based on the treatment center they attended: governmental group (G; n = 45) and private group (P; n = 44). Immediately after debonding, the examination of buccal caries and WSLs on premolars and anterior teeth was carried out using the ICDAS-II and the DIAGNOdent Pen. Cross-tabulation was applied to study the correlation between the ICDAS-II index and the DIAGNOdent Pen by calculating the Spearman correlation coefficient. Results: The G group showed a significantly higher (P < .0001) prevalence of WSLs and/or buccal caries compared to that of the P group based on evaluation by the two methods. Based on ICDAS-II, 43% of the patients in the P group and 9% in the G group were free from any WSLs. In the G group, 22% of the patients had ≥16 lesions, whereas there were none for the P group. The Spearman correlation coefficient between the two methods was .71. Conclusions: The prevalence of caries and/or WSLs at debonding was significantly higher in the G group compared to the P group. The clinical index (ICDAS-II) showed a good correlation with the DIAGNOdent Pen.
|
|
| 8. |
- Almosa, Naif Abdullah, 1981, et al.
(författare)
-
Diagnosing the severity of buccal caries lesions in orthodontic patients at de-bonding using digital photographs.
- 2014
-
Ingår i: Acta odontologica Scandinavica. - : Informa UK Limited. - 1502-3850 .- 0001-6357. ; 72:6, s. 474-480
-
Tidskriftsartikel (refereegranskat)abstract
- Abstract Objective. The aims of this study were (1) to evaluate the severity of buccal caries lesions according to the International Caries Detection and Assessment System (ICDAS) criteria via scoring buccal caries lesions on digital photographs at the time of de-bonding and (2) to compare this method with clinical examination. Materials and methods. In total, 89 patients treated with upper and lower fixed appliances were clinically examined immediately after de-bonding by the first author and buccal caries were scored according to the ICDAS-II. Close-up digital photographs were taken of 245 teeth with different buccal caries lesion scores according to the ICDAS-II. Thirteen postgraduate orthodontics students independently scored the buccal caries lesions in the digital photographs using the modified clinical criteria (ICDAS-II). Intra- and inter-examiner reliabilities were evaluated by calculating the weighted kappa. To evaluate the validity of diagnosing the severity of buccal caries lesions using digital photographs compared to clinical examination, Spearman's correlation coefficient was calculated. Results. Intra-examiner reliability and the reliability between each examiner and the clinical examination showed moderate-to-excellent agreement, with kappa values of 0.52-0.83. Scoring buccal caries lesions via clinical examinations and scoring via photographs were well correlated according to the modified ICDAS-II criteria (Spearman's correlation coefficient, 0.76). Conclusions. Thus, scoring buccal caries lesions on digital photographs according to ICDAS-II criteria is a reliable and valid method for assessing the severity of buccal caries lesions.
|
|
| 9. |
- Bäckman, B, et al.
(författare)
-
The absence of correlations between a clinical classification and ultrastructural findings in amelogenesis imperfecta.
- 1993
-
Ingår i: Acta odontologica Scandinavica. - 0001-6357. ; 51:2, s. 79-89
-
Tidskriftsartikel (refereegranskat)abstract
- This study was performed to examine whether a clinical classification of different phenotypes of amelogenesis imperfecta could be discernible at the ultrastructural level. Seventeen primary teeth from 16 children with hypomineralization, hypomaturation, or hypoplastic variants of the disease were collected for histologic studies of the enamel by means of polarized light microscopy, scanning electron microscopy (SEM), and secondary ion mass spectrometry (SIMS). Polarization microscopy showed that the enamel was hypomineralized; in six teeth a wavy configuration of the enamel prisms also appeared. Three histomorphologic main types could be discerned. In 10 of the teeth extensive hypomineralization of the bulk of the enamel was found. One tooth had an unusually thick enamel with only a thin normally mineralized surface layer. SIMS images showed less pronounced signals from Ca2+ and Na+ but with stronger signals from Cl- and CN-, representing the organic component of enamel. The SEM images showed an irregular prism pattern with marked interprismatic areas. Irrespective of the clinical appearance or the hereditary pattern the main findings were hypomineralized enamel with or without wavy bands. Neither of the analytical methods used in this paper distinguishes between the clinical phenotypes of amelogenesis imperfecta.
|
|
| 10. |
- Granath, Johanna, et al.
(författare)
-
Interproximal grinding (disking) of caries in primary molars, attiudes and the extent utilized in a Swedish County
- 2018
-
Ingår i: Acta Odontologica Scandinavica. - : Informa UK Limited. - 0001-6357 .- 1502-3850. ; 76:6, s. 394-400
-
Tidskriftsartikel (refereegranskat)abstract
- Objective: To assess the occurrence of interproximal grinding as a caries therapy in primary molars, to what degree grinding replaced conventional restorative caries therapy, to what extent anaesthesia was used while grinding and to assess open comments about attitudes about grinding. Materials and methods: A questionnaire was sent to 108 public dental service clinics with questions concerning the use of grinding as a therapy and alternative to restorative treatment, the use of anaesthesia prior to conventional caries therapy and grinding, respectively. In addition, a content analysis of open comments about grinding was performed. Results: Grinding had been performed in 96% of the clinics. Two-thirds of the dentists used grinding as an alternative to conventional restorative treatment at some point. Most dentists used anaesthesia prior to restorative therapy. Prior to grinding, the frequency of anaesthesia was lower (median 5.0) than for conventional restorative therapy (median 8.7) (p < .001). The open comment analysis revealed complex reasons for the use of grinding. Conclusions: Grinding has been widely practiced in parts of Sweden, is presently a technique employed by a multitude of dentists, and that anaesthesia is used less frequently prior to grinding, in comparison to conventional restorative therapy. Dentist considered grinding as a treatment option in specific situations.
|
|
