| 1. |
- Sahlstrand, Pia, et al.
(författare)
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Timing of mineralization of homologues permanent teeth - an evaluation of the dental maturation in panoramic radiographs.
- 2013
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Ingår i: Swedish Dental Journal. - 0347-9994. ; 37:3, s. 111-119
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Tidskriftsartikel (refereegranskat)abstract
- Clinically the condition Molar Incisor Hypomineralization (MIH), varies considerably between individuals, where any number of molars, from one to all four permanent first molars, may be affected with different degrees of hypomineralized enamel within the same dentition. An explanation to these variations could be that the start of the enamel mineralization differs between homologues teeth. The aim of this study was to compare the dental development between homologues teeth in digital panoramic radiographs (PRs), from children aged 7 to 11 years, using the Gleiser and Hunt method on second and third molars and to calculate the crown/root ratio for the mandibular premolars. 77 PRs, from individuals between 7.3 and 11.0 years of age, were studied. Differences in developmental stages between homologues teeth (second and third molars) were studied. In 72 of these PRs, the crown/root ratio of mandibular premolars was also compared. In 31 of the PRs, a difference in development was found between the right and left maxillary second molar. In 22 PRs, a difference in development between the right and left mandibular second molar was found. In 17 of the PRs, a difference in development was found between the right and left maxillary third molars. In 26 PRs, a difference in-between the right and left mandibular third molar was found. In 72 PRs, the crown/root ratio of mandibular premolars was measured and differences were found. All these differences were significant. A possible explanation to the variations in expressivity of MIH may be a result of differences in the start of mineralization between homologues teeth.
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| 2. |
- Bjarnason, Sibilia, et al.
(författare)
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Bonded resin sealant on smooth surface dental enamel--an in vitro study.
- 2003
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Ingår i: Swedish dental journal. - 0347-9994. ; 27:4, s. 167-74
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to in vitro evaluate the micro leakage of a fissure sealant on sound and demineralized enamel using thermo cycling. The effect of the sealing procedure on sound and demineralized enamel were assessed on human premolars that were divided into one Control group and two Test groups. The Control group served as a baseline reference for the subsequent test procedures. The crowns of five teeth were covered with wax leaving three separate windows on the buccal surfaces. The enamel in one window was acid-etched, in the second window demineralized, and in the third window demineralized and subsequently acid-etched. In Test group 1, containing ten teeth, a defined enamel area on the buccal surfaces was acid-etched and sealed. The sealed area and a border of sound enamel around it were subjected to the demineralizing procedure. In Test group 2, a defined enamel window of 13 teeth was demineralized and subsequently etched and sealed. The sealed area and a border of surrounding enamel were subjected to a new cycle of demineralization. The longitudinal, bucco-lingual sections were examined in polarized light. When placed on acid-etched surfaces, the resin adhered firmly to the enamel with no evidence of demineralization or enlargement of previously demineralized areas underneath the sealants.
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| 3. |
- Gumaelius, Lena, et al.
(författare)
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Outreach initiatives operated by universities for increasing interest in science and technology
- 2016
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Ingår i: European Journal of Engineering Education. - : Taylor & Francis Group. - 0304-3797 .- 1469-5898. ; , s. 1-34
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Tidskriftsartikel (refereegranskat)abstract
- Since the 1990s, the low number of students choosing to study science and technology in higher education has been on the societal agenda and many initiatives have been launched to promote awareness regarding career options. The initiatives particularly focus on increasing enrolment in the engineering programmes. This article describes and compares eight European initiatives that have been established and operated by universities (and in some cases through collaboration with other actors in society). Each initiative is summarised in a short essay that discusses motivation, organisation, pedagogical approach, and activities. The initiatives are characterised by comparing the driving forces behind their creation, how the initiative activities relate to the activities at the university, size based on the number of participants and cost per participant and pedagogical framework. There seem to be two main tracks for building outreach activities, one where outreach activities are based on the university's normal activities, and one where outreach activities are designed specifically for the visiting students.
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| 4. |
- Norén, Agneta, 1954-
(författare)
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Metabolic regulation of nitrogenase in Rhodospirillum rubrum : studies on DRAG and DRAT, the regulatory proteins of dinitrogenase reductase
- 1998
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Nitrogen fixation is catalyzed by nitrogenase, in an ATP-dependent reaction where dinitrogen is reduced to ammonium. Nitrogenase is a protein complex consisting of two proteins; dinitrogenase and dinitrogenase reductase and the reaction is only carried out by prokaryotes. In the photosynthetic bacterium, Rhodospirillum rubrum, nitrogen fixation is regulated at both a genetic and a metabolic level. The metabolic regulation is excerted through post-translational modification of dinitrogenase reductase, causing inactivation of the enzyme when so called switch-off effectors are added. The post-translational modification has been shown to be an ADP-ribosylation on Arg-101 of dinitrogenase reductase. The regulatory proteins are; dinitrogenase reductase ADP-ribosyl transferase (DRAT), catalyzing modification and dinitrogenase reductase activating glycohydrolase (DRAG) catalyzing demodification. Both DRAG and DRAT are subjected to post-translational regulation in the cell. The internal signals for this regulation are still not identified and have been the focus of this thesis.By changing the concentration of NAD+ in R.rubrum a reversible decrease in nitrogenase activity could be observed. This decrease in activity was shown to be correlated to a post-translational modification of dinitrogenase reductase by SDS-PAGE and Western blot. The modification is catalyzed by DRAT since studies on a DRAT- mutant show no response at all to additional NAD+. Shortening the switch-off period by addition of NADH generating compounds, confirmed that a change in NAD+ /NADH ratio affects the duration of the switch-off period. Using in vivo fluorometry to study the effect of changes in the NAD+ concentration when nitrogenous switch-off effectors were added, showed that ammonium and glutamine momentarily change the concentration of NAD+. On the basis of these results we suggest that the signal pathway for DRAT activation involves changes in the concentration of NAD+.The membrane associated DRAG is shown to be released by treating the chromatophores with MgGDP, similar treatment with MgGTP, MgATP or MgADP did not result in such a release. Upto 40% of DRAG activity can be found in the supernatant compared to 0.5 M NaCl treated membranes. The chromatophore membranes are shown to have GTPase activity with and without DRAG associated to the membranes indicating the presence of a GTP hydrolyzing protein in the chromatophore membrane. Crosslinking studies demonstrated a high molecular weight complex, that crossreacted with DRAG antibodies.The regulation of DRAG is suggested by us to be mediated by the chromatophore membrane possibly involving a protein complex with GTPase activity. DRAG is suggested to be active in its soluble form and inactive when bound to the membranes.
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| 5. |
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| 6. |
- Oldin, Anna, et al.
(författare)
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Individual risk factors associated with general unintentional injuries and the relationship to traumatic dental injuries among children aged 0-15 years in the Swedish BITA study
- 2016
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Ingår i: Dental Traumatology. - : Wiley. - 1600-4469. ; 32:4, s. 296-305
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Tidskriftsartikel (refereegranskat)abstract
- AimTo investigate general unintentional injuries (GUI) and traumatic dental injuries (TDI) in relation to behavioral and psychosocial strengths and difficulties among Swedish children aged 0-17 years, and to investigate general unintentional injuries in relation to temperament and socioeconomic status among the same children. Subjects and methodsThe study included 2363 children in four different age cohorts aged 3, 7, 11, and 15 years at the study start. Twelve Public Dental Service clinics in Sweden participated, representing different types of demographic areas, both rural and urban. Data were collected from parents and children through an interview, questionnaires, and dental records. ResultsTwenty-four percentage (24%) of the children had experienced a serious general unintentional injury (GUI) at some point during their lifetime up until 3 months prior to the study start. Children who were regarded by their parents as being injured more often than other children also had occasions with general unintentional injuries to a greater extent. Most general unintentional injuries occurred at home. Children with incidents of general unintentional injuries had occasions with TDI to a greater extent than children without general unintentional injury. Children, whose mothers had 11 years of school/education or less, were involved in more general unintentional injuries during the 3-month period prior to the study start, compared to children of mothers with higher education level. ConclusionsChildren with general unintentional injuries had more traumatic dental injuries. Children who were assessed by their parents as being injured more often than other children also had occasions with general unintentional injuries to a greater extent. Temperament, behavioral and psychosocial strengths and difficulties had different impacts at different ages for experiencing a general unintentional injury.
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| 7. |
- Oldin, Anna, et al.
(författare)
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Temperamental and socioeconomic factors associated with traumatic dental injuries among children aged 0-17 years in the Swedish BITA study
- 2015
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Ingår i: Dental Traumatology. - : Wiley. - 1600-4469. ; 31:5, s. 361-367
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Tidskriftsartikel (refereegranskat)abstract
- Aim: The aim of the study was to identify individual risk factors for traumatic dental injuries (TDI) among Swedish children aged 0-17 years. The studied risk factors were temperamental reactivity of the child, family structure, parent's country of birth, and the socioeconomic status of the family represented by parental education and occupation. Subjects and methods: The study included 2363 children in four different age cohorts at 12 public dental service clinics in Sweden, representing different types of demographic areas, both rural and urban. Data were collected from parents and children through an interview and questionnaires. Results: The more social and active children in the two older age cohorts showed less occasions of TDI. Having one parent/guardian protected the child from dental injury just as well as two parents/guardians. Parents born outside of the Nordic countries showed children with less TDI. Low parental education was related to more occasions of TDI among the children. Conclusions: This study has increased the knowledge on certain individual risk factors for TDI. To prevent dental injuries, information could be given to families and children at risk.
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| 8. |
- Oldin, Anna, et al.
(författare)
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Traumatic dental injuries among children aged 0–17 years in the BITA study – A longitudinal Swedish multicenter study
- 2015
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Ingår i: Dental Traumatology. - : Wiley. - 1600-4469 .- 1600-9657. ; 31:1, s. 9-17
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Tidskriftsartikel (refereegranskat)abstract
- Abstract BACKGROUND/AIM: To prevent traumatic dental injuries (TDI), there is a need for vital information. This information could be reached using certain specific variables. The aim of this study, therefore, was to investigate TDI in different age groups, their etiology, and differences by gender, in Swedish children aged 0-17 years. SUBJECTS AND METHODS: The study included 2363 children in four different age cohorts from 12 Public Dental Service clinics in Sweden. The design was a 5-year longitudinal study including yearly clinical examinations, retrospective and prospective data compiled from dental records and interviews regarding TDI. RESULTS: The prevalence for TDI was 37.6% (889) with no gender differences. Boys suffered more injuries during the spring and fall compared to girls. The incidence of 2.8% varied between the age groups where preschool children presented the highest incidence. No changes in prevalence for TDI were found for the years included in the study. The most common reason for TDI was Falling (42.1%). The frequencies for the etiological factors varied between the ages. CONCLUSIONS: The TDI prevalence showed to be stable at a high level in spite of great efforts in Sweden and worldwide to reduce it. Knowledge in why, where, and when TDI appears is therefore essential for dental personnel who will work to reduce TDI.
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| 9. |
- Robertson, Agneta, 1954, et al.
(författare)
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A retrospective evaluation of traumatized permanent teeth.
- 1997
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Ingår i: International journal of paediatric dentistry / the British Paedodontic Society [and] the International Association of Dentistry for Children. - 0960-7439. ; 7:4, s. 217-26
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Tidskriftsartikel (refereegranskat)abstract
- The purpose of this retrospective study (15 years follow-up) was to evaluate the long-term results of treatment to injured teeth following acute trauma. A total of 198 patients with 488 injured teeth were available for analysis. Uncomplicated crown fractures were restored with composite restorations in 106 teeth. 19% of the restorations had been replaced more than 10 times and at the final examination approximately 25% were rated as unacceptable, i.e. needing clinical treatment. Fixed prosthetic therapy had been provided for 106 teeth and endodontic treatment had been provided in 114. Colour changes appearing at late stage suggested obliteration, necrosis or endodontically treated teeth. Anterior composite restorations have been considered acceptable as semi-permanent restorations in patients of early school age (7-15 years), and may have been an advance on what was possible previously, but results of this clinical study suggest that they still do have major shortcomings. There remains a need for a simple, conservative method of restoring aesthetics to fractured and discoloured anterior teeth for clinical use in young patients of late school age.
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| 10. |
- Robertson, Agneta, 1954, et al.
(författare)
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Incidence of pulp necrosis subsequent to pulp canal obliteration from trauma of permanent incisors.
- 1996
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Ingår i: Journal of endodontics. - 0099-2399. ; 22:10, s. 557-60
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Tidskriftsartikel (refereegranskat)abstract
- Little long-term data are available on the frequency by which pulp canal obliteration (PCO) subsequent to trauma leads to pulp necrosis (PN). In this study, 82 concussed, subluxated, extruded, laterally luxated, and intruded permanent incisors presenting with PCO were followed for a period of 7 to 22 yr (mean 16 yr). At final clinical examination, 51% of the observed teeth responded normally to electric pulp testing (EPT). An additional 40% of the teeth although not responding to EPT were clinically and radiographically within normal limits. Yellow discoloration was a frequent finding. During the observation period, periapical bone lesions suggesting PN developed in seven teeth (8.5%). Twenty-yr pulp survival rate was 84%, as determined from life-table calculations. There was no higher frequency of PN in obliterated teeth subjected to caries, new trauma, orthodontic treatment, or complete crown coverage than intact teeth. Although the incidence of PN in teeth displaying PCO seems to increase over the course of time, prophylactic endodontic intervention on a routine basis does not seem justified.
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