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- Tidehag, Per, et al.
(författare)
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Digital dentistry calls the change of ceramics and ceramic processes
- 2019
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Ingår i: Advances in Applied Ceramics. - : Informa UK Limited. - 1743-6753 .- 1743-6761. ; 118:1-2, s. 83-90
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Tidskriftsartikel (refereegranskat)abstract
- Since the start of the new digital impression-taking era which started around 2008 with the introduction of the 3M Lava COS, a slow transformation is gaining momentum and it looks as if this and next year will have a broad impact on the clinicians. From being merely a way of replacing impressions now the total digital workflow enters the industry. This means a whole new way of thinking and a new way to produce prosthetic work where a reproducible constant quality can be achieved. An obvious development of improved ceramic materials that simultaneously can satisfy the mechanical, bio- and aesthetic demands of the prostheses and the corresponding technologies for production that would work for the clinic digital workflow is out of the expertise of the dentists. This calls for a cross-disciplinary collaboration with the experts in the communities of ceramics and digital manufacturing.
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| 3. |
- Tidehag, Per, et al.
(författare)
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Accuracy of ceramic restorations made using an in-office optical scanning technique : an in vitro study
- 2014
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Ingår i: Operative dentistry. - : Operative Dentistry Inc, Indiana Univ School Dentistry. - 0361-7734 .- 1559-2863. ; 39:3, s. 308-316
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Tidskriftsartikel (refereegranskat)abstract
- The present in vitro study concerns determination of the pre-cementation gap width of all-ceramic crowns made using an in-office digital-impression technique and subsequent computer-aided design/computer-aided manufacturing (CAD/CAM) production. Two chairside video camera systems were used: the Lava Oral scanner and Cadent's iTero scanner. Digital scans were made of a first molar typodont tooth that was suitably prepared for an all-ceramic crown. The digital impressions were sent via the Internet to commercial dental laboratories, where the crowns were made. Also, an impression of the typodont tooth was made, poured, and scanned in order to evaluate the pre-cementation gap of crowns produced from scanning stone dies. These methods and systems were evaluated by creating replicas of the intermediate space using an addition-cured silicone, and the gap widths were determined using a measuring microscope. Hot-pressed leucite-reinforced glass-ceramic crowns were selected as a reference. The mean value for the marginal measuring points of the control was 170 μm, and the values for all the evaluated crowns ranged from 107 to 128 μm. Corresponding figures for the internal measuring points were 141-210 μm and 115-237 μm, respectively. Based on the findings in the present study, an in-office digital-impression technique can be used to fabricate CAD/CAM ceramic single crowns with a marginal and internal accuracy that is on the same level as that of a conventional hot-pressed glass-ceramic crown. In the present study, however, slight differences could be seen between the two types of ceramic crowns studied with respect to the internal fit obtained.
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| 4. |
- Isaksson, Hanna, et al.
(författare)
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High-fiber rye diet increases ileal excretion of energy and macronutrients compared with low-fiber wheat diet independent of meal frequency in ileostomy subjects
- 2013
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Ingår i: Food & Nutrition Research. - Järfälla : Co-Action Publishing. - 1654-6628 .- 1654-661X. ; 57, s. 18519-
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Tidskriftsartikel (refereegranskat)abstract
- Background: Whole-grain foods and cereal dietary fiber intake is associated with lower body weight. This may partly result from lower energy utilization of high-fiber diets. Objective: In the present study, the impact on ileal excretion of energy and macronutrients in response to a rye bread high-fiber diet compared to a refined wheat low-fiber diet was investigated. Furthermore, the effect of meal frequency on apparent absorption of nutrients was studied for the first time. Design: Ten participants that had undergone ileostomy consumed standardized iso-caloric diets, including low-fiber wheat bread (20 g dietary fiber per day) for 2 weeks followed by high-fiber rye bread (52 g dietary fiber per day) for 2 weeks. The diets were consumed in an ordinary (three meals per day) and a nibbling (seven meals per day) meal frequency in a cross-over design. Ileal effluents were collected during 24 h at the third day of each of the four dietary periods and analyzed for gross energy and nutrient contents. Results: The results showed that intake of rye bread high-fiber diet compared to the refined wheat low-fiber diet caused an increase in ileal excretion of energy and macronutrients. The effect was independent of meal frequency. This suggests that a high intake of rye may result in lower availability of macronutrients for small intestinal digestion and absorption. A regular intake of rye may therefore have implications for weight management.
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| 6. |
- Holm, Charlotta, et al.
(författare)
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Longevity and quality of FPDs: a retrospective study of restorations 30, 20, and 10 years after insertion.
- 2003
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Ingår i: International Journal of Prosthodontics. - 0893-2174. ; 16:3, s. 283-9
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: The aim of this retrospective study was to investigate the longevity and clinical performance of fixed partial dentures (FPD) 30, 20, and 10 years after insertion. MATERIALS AND METHODS: A total of 289 FPDs were inserted in 1966/67, 1976/77, and 1986/87. For patients with FPDs presumably still in function, an evaluation according to the CDA criteria was made. RESULTS: For 64 of the FPDs (22%), no information was available. Seventy-nine patients with 94 FPDs (33%) were clinically examined, and 44 of the FPDs (15%) were reported to be still in function by the patients' current clinicians. The remaining 87 FPDs (30%) were considered lost to follow-up. These FPDs had either been removed for various reasons--in most cases dental caries, lost retention, or fractured abutment teeth--or the patient could not be contacted. Eighty-four percent of the FPDs inserted in 1966/67 were still in function after 20 years, compared to 64% of those inserted in 1976/77. Apart from an increase in wear and discoloration, the oldest FPDs had excellent marginal fit and anatomic shape. CONCLUSION: The survival rate of 30-year-old FPDs was high; 53% remained in function after 30 years. Based on the CDA criteria, 78% of the restorations were rated satisfactory in all subgroups. The FPDs placed in 1966/67 obtained the highest ratings in color, anatomy, and margin integrity.
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| 9. |
- Tidehag, Per, 1959-
(författare)
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Iron absorption and iron status related to diet : an experimental and epidemiological study
- 1995
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The absorption of iron from the diet is a major determinant of the iron status of an individual. Accurate measures of iron absorption are thus essential in the determination of the effects of diet composition on iron absorption and status.The aim of these studies have firstly been to investigate different methods to measure iron absorption and effects of diet in both rats and humans. Secondly to describe variations in iron status in a general population and to relate the variations to diet.Experimental studies in rats: The most important factors determining the availability of iron from the diet to growing rats appears to be the concentration of iron in the diet and the iron status of the rats. The type of cereal |rain in the diet and the diet phytate and fiber concentrations were of far less importance. The absorption of Fe from test meals, the iron balance over a period of a few days and the blood hemoglobin and serum and liver iron concentrations were in good general agreement on the effects of diet and iron status on the bioavailability of iron from grain diets. The extent of coprophagy in rats is not affected by diet or iron status and did not affect iron absorption appreciably.Effect of dairy products on iron absorption in man: The effect of milk and fermented milk on iron absorption was studied in nine ileostomy subjects. We found no decrease in iron absorption during two three-week periods on a high calcium (milk) diet. The results of the present study differ from those studies in which the absorption of radioiron from test meals was measured, which have shown a pronounced effect of high calcium levels. We believe that these differences in results were caused by differences in experimental design and choice of measurement method. Our results support earlier findings that the iron status of the subject rather than the bioavailability of dietary iron is the major factor determining absorption of dietary non-heme iron.Measurement of iron absorption from single meals and daily diets in humans using radioiron: Ten ileostomy subjects were given the same composite diet for all three meals each day for five consecutive days (meal proportion ratio 1:2:4 for breakfast, lunch and dinner respectively). The iron absorption from a low-fiber diet measured from the morning meals (55Fe) was almost 80% higher than the average iron absorption measured from all meals (59Fe) during the last two days on this diet. The iron absorption from a high fiber diet eaten at breakfast was almost 50% higher than the daily average absorption. This suggests that all meals of the day should be labeled with radioiron and not just the morning meal.Population studies of diet and iron status: In a randomly selected population in Northern Sweden lower iron status was associated with a high intake of dairy products in women (25-44 yr.). The striking result was however that iron status was not related to other major variations in dietary intake, particularly intake of energy and iron. No correlation could be demonstrated between iron status measured as ferritin, serum iron or TIBC and the estimated intakes of calcium, fiber, ascorbic acid, meat, tea or coffee, all of which are known to be factors which influence the bioavailability of iron. On the population level, factors other than diet, e.g. menstruation and metabolic factors, were more important than diet as determinants of iron status.
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