Publikasjoner
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Brox, Julie Marie Haabeth; Tulek, Amela; Khan, Qalbi; Sehic, Amer; Stein, Linda & Breivik, Anne
[Vis alle 8 forfattere av denne artikkelen]
(2026).
Erosive tooth wear – knowledge and treatment preferences among dental hygienists.
Acta Odontologica Scandinavica.
ISSN 0001-6357.
85,
s. 332–341.
doi:
10.2340/aos.v85.46261.
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Objective: Erosive tooth wear (ETW) is generally recognized as a widespread condition and a rising concern within the oral healthcare system. This study aimed to investigate dental hygienists` experiences and treatment methods regarding ETW in young adults.
Material and methods: A questionnaire was sent to 1,084 Norwegian dental hygienists working in both public and private dental services. In total, 313 responded (response rate 28.9%). After excluding 47 respondents who did not meet the inclusion criteria of working with young adults (15–30 years), 266 dental hygienists were included in the final analyses (24.5% of those invited).
Results: In total, 96% of the study population of 266 dental hygienists reported recording ETW in the register, with the public dental service doing so more frequently than the private sector. Sports drinks, energy drinks and soft drinks were believed to be the primary risk indicators of ETW, analogously across groups. Furthermore, there was consensus that the most frequently performed preventive measures were dietary guidance and self-administration of fluoride rinse and/or tablets.
Conclusions: Overall, this study suggests that, in our sample, dental hygienists possess substantial knowledge of ETW and hold strong views on potential improvements in their work as healthcare professionals.
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Thune, Noora Helene; Kristensen, Anna Tostrup; Hammer, Hugo Lewi; Khan, Qalbi; Utheim, Tor Paaske & Sehic, Amer
(2026).
Evaluating digital resources as a supplement to traditional anatomy teaching in dental education.
Frontiers in Dental Medicine.
7.
doi:
10.3389/fdmed.2026.1781318.
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Kristoffersen, Camilla Sofia Miranda; Ziesler, Camilla Elise Øxnevad; Thune, Noora Helene; Kristensen, Anna Tostrup; Utheim, Tor Paaske & Hammer, Hugo Lewi
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(2026).
Histogenetics in Teaching the Complexity of Developmental Biology to Dental Students: A Study Merging Traditional and Current Approaches.
Dentistry Journal.
14(3).
doi:
10.3390/dj14030177.
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Kristensen, Anna Tostrup; Thune, Noora Helene; Khan, Qalbi; Utheim, Tor Paaske; Hammer, Hugo Lewi & Sehic, Amer
(2026).
Student perspectives on integrating basic and clinical dental sciences: insights from three dental schools in Norway.
Frontiers in Dental Medicine.
7.
doi:
10.3389/fdmed.2026.1746468.
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Thune, Noora Helene; Kristensen, Anna Tostrup; Khan, Qalbi; Utheim, Tor Paaske; Hammer, Hugo Lewi & Sehic, Amer
(2025).
Retention of skull anatomy knowledge in dental education: a comparative study.
Frontiers in Dental Medicine.
6,
s. 1–9.
doi:
10.3389/fdmed.2025.1596610.
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There is limited evidence regarding the retention of essential basic science knowledge among dental students and professionals. Understanding the anatomy of the skull, osteology, is crucial as it provides the structural framework essential for comprehending head anatomy, where various soft tissue components are organized. This study aims to evaluate and compare the retention of osteological knowledge across different stages of dental education and professional practice. Specific anatomical structures on selected skull bones and the complete cranium, taught at the pre-clinical level and including clinically and radiographically significant landmarks, were marked for assessment. The study evaluated the ability of second year and f ifth year undergraduate dental students, as well as postgraduate students at various stages of specialist training in different dental fields, to independently identify these marked anatomical structures. The study demonstrated significantly higher identification accuracy among second year students compared to fifth year and postgraduate students (p<0.05). Second year students achieved over 90% accuracy for individual skull bones, with slightly lower accuracy for the entire cranium (85.9%). Fifth year students showed markedly lower retention, with accuracy below 50%, ranging from 20.8% (cranium) to 48.3% (mandible). Postgraduate students performed similarly to f ifth year students, notably with only 11.8% accuracy for the sphenoid bone. Significant differences in accuracy were observed among postgraduate specialties (p <0.05), with oral surgery and oral medicine specialists achieving the highest accuracy (81.2% for the mandible). However, no significant correlation between years of experience and accuracy was observed among the postgraduate groups (p=0.45). Our results indicate that clinically and radiologically relevant anatomical knowledge is better retained over time, while overall osteological knowledge significantly declines. This highlights the need for strategies beyond initial learning to enhance long-term retention. Integrating clinical, radiological, and surface anatomy into continuing dental education could substantially improve knowledge retention. Furthermore, our f indings suggest potential benefits from increased vertical integration and encourage broader discussion regarding the traditional separation between pre-clinical and clinical training phases.
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Døving, Mats; Galteland, Pål; Næss, Ingar; Sehic, Amer; Dalby, Marius & Utheim, Tor Paaske
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(2025).
Craniofacial Soft Tissue Injuries: An Observational Study of Bicycling Injuries from a Level 1 Trauma Center.
The Journal of craniofacial surgery (Print).
ISSN 1049-2275.
36(8),
s. 2696–2700.
doi:
10.1097/SCS.0000000000011409.
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Craniofacial injuries in bicycling accidents are common, yet limited information exists on associated soft tissue injuries. This study aims to investigate the prevalence and anatomic patterns of such injuries, and their association with helmet use and craniofacial fractures. The study included 1543 patients with bicycle injuries from a level 1 trauma center. Retrospective chart review was conducted for patients with craniofacial soft tissue injuries. Craniofacial soft tissue injuries were identified in 646 cyclists (41.9%). Odds of injury increased with years of age [aOR 1.02 (1.01–1.02), P<0.001], and women were at a higher risk compared with men [aOR 1.35 (1.05–1.75), P=0.02]. Injuries were distributed across the scalp (19%), upper third (56%), midface (69%), and lower third (32%) of the face. Helmets were used by 38% of the patients with soft tissue injuries. Helmet use reduced the odds of craniofacial soft tissue injuries overall [aOR 0.49 (0.39–0.62), P<0.001], scalp injuries [aOR 0.17 (0.10–0.28), P<0.001], and upper facial injuries [aOR 0.41 (0.31–0.54), P<0.001]. Conversely, helmet use increased the odds of lower facial injuries [aOR 1.48 (1.07–2.05), P=0.018]. Strong associations were found between lower face soft tissue injuries and mandible fractures [aOR 29.27 (15.50–55.30), P<0.001] and between soft tissue injuries of the midface and nasal bone fractures [aOR 22.70 (12.52–41.16), P<0.001]. Thus, craniofacial soft tissue injuries in cyclists are influenced by age, sex, and helmet use. Helmet use is associated with decreased odds of soft tissue injury of the upper face but with increased odds of soft tissue injury of the lower facial third.
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Brox, Julie Marie Haabeth; Tulek, Amela; Sehic, Amer; Mulic, Aida Gacic; Utheim, Tor Paaske & Khan, Qalbi
(2025).
Comparative analysis of the protective effects of fluoride compounds on dental erosion in mouse model.
BMC Oral Health.
25(1),
s. 1–10.
doi:
10.1186/s12903-025-05767-z.
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Background Dental erosion development is affected by various factors such as types and amounts of acids, drinking habits and lifestyle choices. To prevent the onset and progression, identification of early erosive lesions as well as increased knowledge of the preventive treatment possibilities is of the importance. The aim of this study is to compare the protective effects of various fluoride compounds against dental erosion utilizing an established mouse model. Methods Three groups of ten young CD-1 mice were provided cola drink ad libitum during six weeks. Fluoride solutions containing metal components, TiF₄ (0.5 mol/l, pH 1.2, 9500 ppm F) and SnF₂ (0.5 mol/l, pH 2.6, 9500 ppm F), and a non-metal fluoride, NaF (0.5 mol/l, pH 8, 9500 ppm F) were applied to the molars under sedation twice a week. Additionally, one positive (acidic drink) and one negative (distilled water) control group were included. Mandibular molars were thereafter dissected and analyzed using scanning electron microscopy (SEM). The first molars were transversely ground, observed by SEM, and tooth height and dental hard tissue loss were measured. Further, pulp structure was described. Results The application of metal fluorides, TiF₄ and SnF₂, resulted in the formation of a protective coating layer on the molars. The overall protective effects of fluoride compounds on the development of dental erosion were evident in increasing succession from NaF, TiF₄ to SnF₂. Molars applied NaF showed a 6% reduction in tooth tissue loss compared to the untreated positive control molars. TiF₄ and SnF₂ treated molars continued to display decreased tooth tissue loss by 37% and 67%, respectively. Conclusions The metal fluorides offer superior protection against dental erosion compared to the traditional fluoride compound. The results particularly emphasize the protective effect of SnF₂, which was most effective in preserving enamel structure and minimizing dentin exposure. This suggests that SnF₂ could be an effective option for preventing dental erosions.
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Brox, Julie Marie Haabeth; Tulek, Amela; Sehic, Amer; Mulic, Aida Gacic; Utheim, Tor Paaske & Khan, Qalbi
(2025).
The Protective Effects of Silver Fluoride Solution and Fluoride Varnish on Dental Erosion—An In Vivo Study.
Dentistry Journal.
13(2).
doi:
10.3390/dj13020046.
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Breivik, Anne; Mulic, Aida Gacic; Sehic, Amer; Valen, Håkon; Kopperud, Simen E. & Stein, Linda Maria
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(2024).
Accumulation and removal of Streptococcus mutans biofilm on enamel and roosurfaces in vitro.
Biomaterial Investigations in Dentistry.
11,
s. 76–82.
doi:
10.2340/biid.v11.41059.
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Objective: This study aimed to quantitatively investigate the accumulation of Streptococcus mutans biofilm on enamel and root surfaces and assess the amount of biofilm removal using (1) experimental toothpaste and (2) water, in a closed system of flow chamber.<p> <p<Methods: Eight sound premolars were embedded in epoxy resin and polished with silicon carbide grinding papers to display enamel and root surfaces. To mimic biofilm, cultures of Streptococcus mutans were prepared and grown on the tooth surfaces over night before they were exposed to either 2 liters of Milli Q water or 2 liters of 40% experimental toothpaste in the flow chamber. The amount of biofilm was measured and quantified in Fluorescence microscopy. Mean fluorescence values were recorded and analysed using Microsoft® Excel® (MS Excel 2016). <p>Results: The ability to grow biofilm was equally present at both the enamel and root surfaces. The use of water and 40% experimental toothpaste showed a significant reduction of areas covered with biofilm on both enamel and root dentin in comparison to untreated surfaces (p < 0.01). Significantly more biofilm was removed from enamel compared to root surfaces when treated with either water and toothpaste (p < 0.01). Slightly less biofilm was removed by the use of water compared to toothpaste on both enamel and root dentin surfaces, although the differences were not statistically significant. <p>Conclusion: The results indicate that less biofilm is removed from the root surfaces than enamel by the use of water and 40% experimental toothpaste in flow chamber. Assessing oral biofilm accumulation and monitoring biofilm formation on enamel and root dentin surfaces give oral health professionals important directions that could strenghten the significance of dental caries prevention. Improving older individuals’ oral hygiene practices should therefore be considered an important measure to prevent root caries.
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Sehic, Amer & Khan, Qalbi
(2024).
Traditional Hands-On Puzzle Method versus Fully Digital Approach in Teaching Tooth Morphology: A Comparative Study of Educational Outcomes.
Dentistry Journal.
12(6).
doi:
10.3390/dj12060162.
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Objective: Tooth morphology education is a critical component of dental curricula, providing a foundational understanding of the intricate structural anatomy of teeth. This study evaluates the learning outcomes in relation to tooth morphology of two student cohorts from different academic terms, comparing the traditional ‘tooth puzzle’ method to an alternative fully digital approach. Materials and Methods: Two groups of Master of Dentistry students were retrospectively analyzed. The control group (55 students) was taught via the ‘tooth puzzle’ method in 2021, while the experimental group (55 students) underwent a fully digital course in 2020 due to COVID-19 restrictions. Both groups completed a digital examination involving the identification of 40 teeth, presented as images and videos. Results: In the control group of 55 students, nearly half (49.1%) achieved faultless results, while 65.5% had at most two faults, and 74.5% had no more than four faults. The group had a total of 163 faults, averaging 3.0 per student, with only one student (1.8%) failing the test. In stark contrast, the experimental group had no students without faults, 9.1% had four or fewer faults, and a significant 61.8% made 10 or more faults, with 29.1% failing their first test attempt by exceeding 12 faults. Overall, the experimental group registered 582 faults, averaging 10.6 per student. Conclusions: The ‘tooth puzzle’ method, with its interactive and tactile elements, proved more effective in teaching tooth morphology than the digital-only approach. The increased number of faults and failed tests in the experimental group suggest that while digital tools offer meaningful support in learning tooth morphology, their main advantage is seen when coupled with traditional hands-on techniques, not unassisted and independently.
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Galteland, Pål; Døving, Mats; Næss, Ingar; Sehic, Amer; Utheim, Tor Paaske & Eken, Torsten
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(2024).
The association between head injury and facial fracture treatment: an observational study of hospitalized bicyclists from a level 1 trauma centre.
Acta Neurochirurgica.
ISSN 0001-6268.
166(1).
doi:
10.1007/s00701-024-06019-9.
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Purpose To compare the types of facial fractures and their treatment in bicyclists admitted to a level 1 trauma centre with major and minor-moderate head injury. Methods Retrospective analysis of data from bicycle-related injuries in the period 2005–2016 extracted from the Oslo University Hospital trauma registry. Results A total of 967 bicyclists with head injuries classified according to the Abbreviated Injury Scale (AIS) were included. The group suffering minor-moderate head injury (AIS Head 1–2) included 518 bicyclists, while 449 bicyclists had major head injury (AIS Head 3–6). The mean patient age was 40.2 years (range 3–91 years) and 701 patients (72%) were men. A total of 521 facial fractures were registered in 262 patients (on average 2 facial fractures per bicyclist). Bicyclists with major head injury exhibited increased odds for facial fractures compared to bicyclists with minor-moderate head injury (sex and age adjusted odds ratio (OR) 2.75, 95% confidence interval (CI) 2.03–3.72, p < 0.001. More specifically, there was increased odds for all midface fractures, but no difference for mandible fractures. There was also increased odds for orbital reconstruction in cyclist with major head injury compared to bicyclist with minor-moderate head injury (adjusted OR 3.34, 95% CI 1.30–8.60, p = 0.012). Conclusion Bicyclists with more severe head injuries had increased odds for midface fractures and surgical correction of orbital fractures. During trauma triage, the head and the face should be considered as one unit.
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Markholm, Caroline Elisabeth; Overskott, Helene Lindén; Sehic, Amer; Utheim, Tor Paaske & Khan, Qalbi
(2024).
Integrating Structured Digital Tools with the Traditional Hands-on Puzzle Method for Teaching Tooth Morphology: A Comparative Study of Educational Outcomes.
Dentistry Journal.
12(8).
doi:
10.3390/dj12080270.
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The study of tooth morphology is a critical component of the dental curriculum, highlighting the importance for dental students to acquire comprehensive and detailed knowledge of the complex structure of teeth. This study compared the educational outcomes of two student cohorts in a tooth morphology course, using traditional methods for the control group and additional digital video-based resources for the experimental group. We hypothesized that early integration of digital resources would significantly reduce the learning time. We retrospectively analyzed two groups of Master of Dentistry students. The control group (42 students) was taught using the traditional ‘tooth puzzle’ method, while the experimental group (42 students) supplemented traditional teaching with digital video-based tools developed by our department. Both groups’ curricula culminated in a practical post-course test requiring the identification of 40 teeth, along with a mid-course test to track the students’ learning progression. The number and type of incorrectly identified teeth were recorded. The mid-course test showed significant performance differences. The control group had a median (Q1, Q3) value of faults of 12.0 (7.8, 20.5), whereas the respective value for the experimental group was 4.0 (0.0, 8.0) (p < 0.001). In the control group, none achieved faultless results, with only two students (4.8%) having at most two faults, and six students (14.3%) having no more than four faults. The control group averaged 13.5 faults per student, with 19 students (45.2%) failing the test. Conversely, the experimental group showed improved performance: 12 students (28.6%) had no faults, and 25 students (59.5%) had four or fewer faults. The experimental group averaged 5.2 faults per student, with only four students (9.5%) failing. By the end of the course, both groups achieved commendable results on the practical tooth identification test. The experimental group slightly outperformed the control group, though the difference was not significant. The median (Q1, Q3) values were 0.0 (0.0, 2.5) and 1.0 (0.0, 4.5) for the experimental and control groups, respectively (p = 0.372). The students using both traditional and structured digital video-based tools showed greater learning advancement than those using only the traditional ‘tooth puzzle’ method.
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Overskott, Helene Lindén; Markholm, Caroline Elisabeth; Sehic, Amer & Khan, Qalbi
(2024).
Different Methods of Teaching and Learning Dental Morphology.
Dentistry Journal.
12(4).
doi:
10.3390/dj12040114.
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Dental anatomy education is traditionally structured into theoretical and practical modules to foster both cognitive and psychomotor development. The theoretical module typically involves didactic lectures where educators elucidate dental structures using visual aids. In contrast, practical modules utilize three-dimensional illustrations, extracted and plastic teeth, and tooth carving exercises on wax or soap blocks, chosen for their cost, ease of handling, and fidelity in replication. However, the efficacy of these traditional methods is increasingly questioned. The criticism in this concern is that oversized carving materials may distort students’ understanding of anatomical proportions, potentially affecting the development of necessary skills for clinical practice. Lecture-driven instruction, on the other hand, is also criticized for its limitations in fostering interactive learning, resulting in a gap between pre-clinical instruction and practical patient care. In this study, we review the various educational strategies that have emerged to enhance traditional dental anatomy pedagogy by describing the effectiveness of conventional didactic lectures, wax carving exercises, the use of real and artificial teeth, the flipped classroom model, and e-learning tools. Our review aims to assess each method’s contribution to improving clinical applicability and educational outcomes in dental anatomy, with a focus on developing pedagogical frameworks that align with contemporary educational needs and the evolving landscape of dental practice. We suggest that the optimal approach for teaching tooth morphology would be to integrate the digital benefits of the flipped classroom model with the practical, hands-on experience of using extracted human teeth. To address the challenges presented by this integration, the creation and standardization of three-dimensional tooth morphology educational tools, complemented with concise instructional videos for a flipped classroom setting, appears to be a highly effective strategy.
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Brox, Julie Marie Haabeth; Tulek, Amela; Sehic, Amer; Mulic, Aida Gacic; Utheim, Tor Paaske & Khan, Qalbi
(2024).
Onset and progression of dental erosion in a mouse model.
Acta Odontologica Scandinavica.
ISSN 0001-6357.
83,
s. 453–460.
doi:
10.2340/aos.v83.41193.
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Objective: Purpose of this research was to examine the onset, progression and wear rates of dental erosion in an established mouse model.<p> <p>Material and methods: Dental erosion in mice was experimentally induced, and the acidic effects of cola drink on their teeth after 2, 4 and 6-weeks were closely analysed by scanning electron microscopy. The tooth height and enamel or dentin loss were established. <p> <p>Results: The dental erosion on the molars showed clear progression from 2 to 6 weeks. By the 2-week mark, a significant portion of enamel was already eroded, revealing the dentin on the lingual cusps. When adjusted for attritional wear, molars exposed to cola for 2 weeks showed a 35% drop in lingual tooth height compared to controls (533 μm vs. 818 μm). At 4 and 6 weeks, the cola-exposed group continued to display decreased lingual tooth heights by 40% (476 μm vs. 799 μm) and 43% (440 μm vs. 767 μm), respectively.<p> <p>Conclusion: This study revealed significant acidic effects of cola drink on mouse molars as early as 2 weeks. These findings highlight the challenge of monitoring dental erosion clinically and underscore the importance of early preventive and intervention measures.
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Mulic, Aida Gacic; Vieira, Alexandre R.; Bezamat, Mariana; Søvik, Jenny Bogstad; Sehic, Amer & Tulek, Amela
(2023).
Association of Locus Xq26.1-27.3 with Erosive Tooth Wear Phenotypes in a Group of Adolescents.
Caries Research.
ISSN 0008-6568.
57(1),
s. 59–66.
doi:
10.1159/000529015.
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Døving, Mats; Næss, Ingar; Galteland, Pål; Ramm-Pettersen, Jon-Terje; Dalby, Marius & Utheim, Tor Paaske
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(2022).
Anatomical distribution of mandibular fractures from severe bicycling accidents: A 12-year experience from a Norwegian level 1 trauma center.
Dental Traumatology.
ISSN 1600-4469.
38(5),
s. 424–430.
doi:
10.1111/edt.12756.
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Background/Aim The mandible makes up a substantial part of the lower face, and is susceptible to injury. Even in helmeted cyclists, accidents may lead to fractures of the mandible because conventional helmets provide little protection to the lower part of the face. In addition, some studies indicate that helmets may lead to an increased risk of mandibular fractures. Thus, the aim of this study was to examine the anatomic distribution of mandibular fractures in injured cyclists and to assess if helmet use influenced the fracture locations. Material and Methods Data from a Norwegian Level 1 trauma center were collected in the Oslo University Hospital Trauma Registry over a 12-year period. Of 1543 injured cyclists, the electronic patient charts of 62 cyclists with fractures of the mandible were retrospectively evaluated in detail. Demographic data, helmet use, and fracture type were assessed. Results Sixty-two patients (4%) had fractures of the mandible, and women had an increased risk (OR 2.49, 95% CI 1.49–4.16, p < .001). The most common fracture site was the mandibular body, followed by the condyle. Isolated mandibular fractures occurred in 45% of the patients and 55% had other concomitant facial fractures. There were 42% of the patients with fractures in multiple sites of the mandible, and 42% had a concomitant dentoalveolar injury. Half of the cyclists were wearing a helmet at the time of the accident and 39% were not. There was no significant difference in fracture distribution between the helmeted and non-helmeted groups. Conclusions Fracture of the mandibular body was the most prevalent mandibular fracture type following bicycle accidents. Women had an increased risk of mandibular fractures compared with men, whereas helmet wearing did not affect the anatomical fracture site.
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Schmalfuss, Andreas Jörn; Sehic, Amer & Brusevold, Ingvild Johnsen
(2021).
Effects of antibiotics on the developing enamel in neonatal mice.
European Archives of Paediatric Dentistry.
ISSN 1818-6300.
s. 1–10.
doi:
10.1007/s40368-021-00677-4.
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Purpose Identifying factors causing Molar-Incisor Hypomineralization (MIH) is an ongoing challenge. Preterm infants, routinely treated with antibiotics in cases of suspected sepsis, are more commonly afected by dental developmental defects. This study aimed to investigate the efects of gentamycin and ampicillin on the developing enamel in neonatal CD-1 mice in vivo.<p> <p>Methods Neonatal mice were randomized into a study (n=36) and a control (n=35) group. Antibiotics were injected intravenously for 4 days. All mice were sacrifced after 15–18 days. Micro-CT was used to analyse the mineral density (MD) of the enamel and the proportion of the enamel object volume (vol%) in frst molars and incisors.<p> <p>Results We demonstrated a signifcantly lower vol% enamel in the maxillary (30.9% vs. 32.7%; p=0.004) and mandibular (32.5% vs. 34.6%; p=0.015) molars in the study group than in the controls. The incisors were divided into segments upon analysis. We demonstrated both lower vol% and lower MD of the enamel in most segments in treated individuals compared to controls (p<0.05).<p> <p>Conclusion The reduced MD and vol% in the molars and incisors are likely to have been caused by the antibiotics given during tooth development. The presented analysis of teeth in neonatal mice with micro-CT could be a valid model for further research on dental developmental defects.
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Tulek, Amela; Mulic, Aida; Runningen, Maria; Diesen, Jannike Lillemo; Utheim, Tor Paaske & Khan, Qalbi
[Vis alle 7 forfattere av denne artikkelen]
(2021).
Genetic Aspects of Dental Erosive Wear and Dental Caries.
International Journal of Dentistry.
ISSN 1687-8728.
2021.
doi:
10.1155/2021/5566733.
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Objectives. &e present review aims to give an overview of the literature focusing on novel genetic aspects of dental erosion and dental caries. Once the tooth erupts into the oral cavity, the regenerative capability of enamel is fundamentally limited due to the loss of dental epithelium during eruption. &e susceptibility or resistance to dental erosion and caries is presumably a result of environmental, phenotypic, and/or genetic influence. Even though it is evident that individuals frequently exposing their teeth to acid and sugar are at high risk of developing dental erosion and caries, the findings exclusively based on these factors are elusive. Data resources and study selection. &e present review was based on data collected from the National Library of Medicine database with different combinations of the following terms: “tooth,” “dental,” “dentin,” “enamel,” “erosion,” “erosive wear,” “caries,” “decay,” “gene,” and “genetic.” A total of forty-six studies met the inclusion criteria. Data were extracted by one reviewer and verified by another. Conclusion. &e high prevalence of erosion and caries among certain groups, and observations that not all individuals appearing to be at risk develop these lesions, has sparked research on identifying genetic effects to these conditions. A connection of genome-wide and candidate gene studies has increased considerably in the literature. &is review reveals largely varying success among studies, demonstrating the difficulties of developing the study with adequate sample sizes and durable phenotype definitions that permit enough statistical power to identify genetic contributors.
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Tulek, Amela; Mulic, Aida; Høgset, Martine; Utheim, Tor Paaske & Sehic, Amer
(2021).
Therapeutic Strategies for Dry Mouth Management with Emphasis on Electrostimulation as a Treatment Option.
International Journal of Dentistry.
ISSN 1687-8728.
2021.
doi:
10.1155/2021/6043488.
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Objectives.
Xerostomia is a subjective sensation of dry mouth. It is commonly associated with salivary gland hypofunction. Both changes in the composition of the saliva and a reduction in the quantity secreted may be an objective finding of dry mouth. Although there are no currently available cures for the conditions resulting in dry mouth, there are several treatment options that give hope for
patients who suffer from xerostomia. Individuals with some residual salivary gland function, which are contraindicated to pharmacological therapies, would benefit the most from identifying novel, alternative effective methods for stimulating production of saliva. The aim of this study was to give an overview of the latest and most relevant data related to treatment modalities for the management of dry mouth conditions.
Data Resources and Study Selection.
The present review was prepared by searching the National Library of Medicine database using the relevant medical terms and their combinations. A total of thirty-three studies met the inclusion criteria. Data were extracted by one author and verified by another.
Conclusion.
A number of patients showed positive treatment outcomes, and the adverse effects of both electrical stimulation (ES) and acupuncture have been reported as mild and transient. In patients who have undergone radiotherapy, acupuncture is shown to increase salivation. However, in patients with Sjogren’s syndrome, the effects of ES devices seem to be elusive. Moreover, due to the instability of the findings in relation to longevity of clinical effect, patient satisfaction, quality of life, and clinical effectiveness of such treatments, the results remain vague.
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Døving, Mats; Galteland, Pål; Eken, Torsten; Sehic, Amer; Utheim, Tor Paaske & Skaga, Nils Oddvar
[Vis alle 8 forfattere av denne artikkelen]
(2020).
Dentoalveolar injuries, bicycling accidents and helmet use in patients referred to a Norwegian Trauma Centre: A 12‐year prospective study.
Dental Traumatology.
ISSN 1600-4469.
s. 1–7.
doi:
10.1111/edt.12627.
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Background/Aim Despite its many benefits, bicycling carries the risk of accidents. Although numerous studies have reported the effect of helmet use on traumatic brain injury, it remains unclear if, and to what extent, helmet use reduces the risk of facial injuries. This is particularly true in regard to injuries of the lower face. In addition, there is limited evidence of the effect of helmet use on dentoalveolar injuries. Thus, the aim of this study was to determine the frequency and distribution of dentoalveolar injuries in bicycling accidents and to explore the influence of helmet use. Material and Methods A total of 1543 bicyclists were included from the trauma registry of a Norwegian tertiary trauma center over a 12‐year period. Data were collected prospectively, including patient characteristics, type of injury, and helmet use. The prevalence of dentoalveolar injuries was assessed in conjunction with helmet use and facial fractures. Results Twenty‐five percent of the patients had maxillofacial injuries, and 18% of those with facial fractures exhibited concomitant dentoalveolar injuries. The most common type of dentoalveolar injury was tooth fracture (39%). The most frequent location of facial fractures with combined dentoalveolar injuries was the maxilla, which had fractured in 32 patients. Women had a higher risk of sustaining dentoalveolar injuries compared to men (odds ratio 1.50, 95% confidence interval 1.02‐2.22). There were 1257 patients (81%) who had reliable registration of helmet use; 54% of these wore a helmet, while 46% did not. Helmet users had an increased risk of dentoalveolar injuries compared to non‐helmeted bicyclists (adjusted odds ratio 1.54, 95% confidence interval 1.02‐2.31). Conclusions Dentoalveolar injuries are fairly common in trauma patients admitted to a trauma center following bicycling accidents. Bicycling helmets are associated with an increased risk of dentoalveolar injuries.
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Enayati, Sam; Chang, Karen; Achour, Hamida; Cho, Kin-Sang; Xu, Fuyi & Guo, Shuai
[Vis alle 14 forfattere av denne artikkelen]
(2020).
Electrical Stimulation Induces Retinal Müller Cell Proliferation and Their Progenitor Cell Potential.
Cells.
9:781(3),
s. 1–18.
doi:
10.3390/cells9030781.
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Non-invasive electrical stimulation (ES) is increasingly applied to improve vision in
untreatable eye conditions, such as retinitis pigmentosa and age-related macular degeneration. Our
previous study suggested that ES promoted retinal function and the proliferation of progenitor-like
glial cells in mice with inherited photoreceptor degeneration; however, the underlying mechanism
remains obscure. Müller cells (MCs) are thought to be dormant residential progenitor cells that possess
a high potential for retinal neuron repair and functional plasticity. Here, we showed that ES with a
ramp waveform of 20 Hz and 300 µA of current was effective at inducing mouse MC proliferation and
enhancing their expression of progenitor cell markers, such as Crx (cone–rod homeobox) and Wnt7,
as well as their production of trophic factors, including ciliary neurotrophic factor. RNA sequencing
revealed that calcium signaling pathway activation was a key event, with a false discovery rate of
5.33 × 10−8
(p = 1.78 × 10−10) in ES-mediated gene profiling changes. Moreover, the calcium channel
blocker, nifedipine, abolished the observed effects of ES on MC proliferation and progenitor cell gene
induction, supporting a central role of ES-induced Ca2+ signaling in the MC changes. Our results
suggest that low-current ES may present a convenient tool for manipulating MC behavior toward
neuroregeneration and repair.
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Tulek, Amela; Mulic, Aida; Stenhagen, Kjersti Refsholt; Galtung, Hilde; Saeed, Muhammad & Utheim, Tor Paaske
[Vis alle 9 forfattere av denne artikkelen]
(2020).
Dental Erosion in Mice with Impaired Salivary Gland Function.
Acta Odontologica Scandinavica.
ISSN 0001-6357.
78,
s. 1–11.
doi:
10.1080/00016357.2020.1734234.
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Objective: Salivary flow rate exerts an essential impact on the development and progression of dental erosion. In this work, the experimental dental erosion in non-obese diabetic (NOD) mice with reduced salivary flow rate was induced, and the erosive effect of acidic drinks on their dentition was studied. Material and methods: Three acidic drinks (sports drink, cola light drink and sugar containing cola drink) were given to adult NOD mice (groups: N = 11) as the only drink for 6 weeks. Two control groups were included; wild type and NOD control (groups: N = 9). Experimental and control (water) teeth were dissected out and observed by scanning electron microscopy (SEM). Mandibular first molars were subsequently embedded in Epon, ground transversely, observed again by SEM, and the enamel thickness and tooth height were measured. Results: Mandibular molars were considerably more eroded than maxillary molars. The erosive process started at the top of the cusps and subsequently extended in the cervical, mesio-distal, and pulpal direction. Erosive lesions were evident in increased succession from sports drink, cola light to cola drink exposed mandibular molars, with the lingual tooth height being approximately 23%, 26%, and 37% lower, respectively, compared to the control. The lingual enamel was approximately 48% thinner in sports drink molars and 62% thinner in cola light molars. In cola drink molars, the lingual enamel was totally eroded, and significant erosion of dentine was evident. Conclusion: Reduced salivary flow, together with a high consumption of acidic drinks, results in severe erosion of NOD mice molars.
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Utheim, Øygunn Aass; Pasovic, Lara; Ræder, Sten; Eidet, Jon Roger; Fostad, Ida & Sehic, Amer
[Vis alle 11 forfattere av denne artikkelen]
(2019).
Effects of explant size on epithelial outgrowth, thickness, stratification, ultrastructure and phenotype of cultured limbal epithelial cells.
PLOS ONE.
14:e0212524(3),
s. 1–22.
doi:
10.1371/journal.pone.0212524.
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Purpose
Transplantation of limbal stem cells is a promising therapy for limbal stem cell deficiency. Limbal cells can be harvested from either a healthy part of the patient’s eye or the eye of a donor. Small explants are less likely to inflict injury to the donor site. We investigated the effects of limbal explant size on multiple characteristics known to be important for transplant function.
Methods
Human limbal epithelial cells were expanded from large versus small explants (3 versus 1 mm of the corneal circumference) for 3 weeks and characterized by light microscopy, immunohistochemistry, and transmission electron microscopy. Epithelial thickness, stratification, outgrowth, ultrastructure and phenotype were assessed.
Results
Epithelial thickness and stratification were similar between the groups. Outgrowth size correlated positively with explant size (r = 0.37; P = 0.01), whereas fold growth correlated negatively with explant size (r = –0.55; P < 0.0001). Percentage of cells expressing the limbal epithelial cell marker K19 was higher in cells derived from large explants (99.1±1.2%) compared to cells derived from small explants (93.2±13.6%, P = 0.024). The percentage of cells expressing ABCG2, integrin β1, p63, and p63α that are markers suggestive of an immature phenotype; Keratin 3, Connexin 43, and E-Cadherin that are markers of differentiation; and Ki67 and PCNA that indicate cell proliferation were equal in both groups. Desmosome and hemidesmosome densities were equal between the groups.
Conclusion
For donor- and culture conditions used in the present study, large explants are preferable to small in terms of outgrowth area. As regards limbal epithelial cell thickness, stratification, mechanical strength, and the attainment of a predominantly immature phenotype, both large and small explants are sufficient.
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Utheim, Øygunn Aass; Lyberg, Torstein; Eidet, Jon Roger; Ræder, Sten; Sehic, Amer & Roald, Borghild
[Vis alle 10 forfattere av denne artikkelen]
(2018).
Effect of transportation on cultured limbal epithelial sheets for worldwide treatment of limbal stem cell deficiency.
Scientific Reports.
8:10502,
s. 1–12.
doi:
10.1038/s41598-018-28553-0.
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Limbal stem cell deficiency can be treated with transplantation of cultured human limbal epithelial cells (LEC). It can be advantageous to produce LEC in centralized labs and thereafter ship them to eye clinics. The present study used transport simulations of LEC to determine if vigorous shaking during transport altered the viability, morphology and phenotype during a 4 day-long storage of LEC with a previously described serum-free storage method. Inserts with LEC cultured on amniotic membranes were sutured to caps inside air-tight containers with generous amounts of 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid (HEPES)-buffered minimal essential medium (MEM). The containers were distributed among the following testing conditions: 6 hours with full containers, 36 hours with full containers, 36 hours with container three quarters full of medium, and 36 hours with container full of medium containing a shear-protecting agent (Pluronic-F68). Compared to stored, but non-transported controls, no statistically significant changes in viability and immunohistochemical staining were observed. The epithelial sheets remained intact. However, an air-liquid interface in the containers reduced the number of desmosomes and hemi-desmosomes compared to the controls. In conclusion, cultured LEC sheets appear to endure vigorous shaking for at least 36 hours if the container is full.
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Utheim, Tor Paaske; Utheim, Øygunn Aass; Salvanos, Panagiotis; Jackson, Catherine; Schrader, Stefan & Geerling, Gerd
[Vis alle 7 forfattere av denne artikkelen]
(2018).
Concise review: Altered versus unaltered amniotic membrane as a substrate for limbal epithelial cells.
Stem Cells Translational Medicine.
ISSN 2157-6564.
7(5),
s. 415–427.
doi:
10.1002/sctm.17-0257.
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Limbal stem cell deficiency (LSCD) can result from a variety of corneal disorders, including chemical and thermal burns, infections, and autoimmune diseases. The symptoms of LSCD may include irritation, epiphora, blepharospasms, photophobia, pain, and decreased vision. There are a number of treatment options, ranging from nonsurgical treatments for mild LSCD to various forms of surgery that involve different cell types cultured on various substrates. Ex vivo expansion of limbal epithelial cells (LEC) involves the culture of LEC harvested either from the patient, a living relative, or a cadaver on a substrate in the laboratory. Following the transfer of the cultured cell sheet onto the cornea of patients suffering from LSCD, a successful outcome can be expected in approximately three out of four patients. The phenotype of the cultured cells has proven to be a key predictor of success. The choice of culture substrate is known to affect the phenotype. Several studies have shown that amniotic membrane (AM) can be used as a substrate for expansion of LEC for subsequent transplantation in the treatment of LSCD. There is currently a debate over whether AM should be denuded (i.e., de‐epithelialized) prior to LEC culture, or whether this substrate should remain intact. In addition, crosslinking of the AM has been used to increase the thermal and mechanical stability, optical transparency, and resistance to collagenase digestion of AM. In the present review, we discuss the rationale for using altered versus unaltered AM as a culture substrate for LEC.
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Risnes, Steinar; Khan, Qalbi; Hadler-Olsen, Elin Synnøve & Sehic, Amer
(2018).
Tooth identification puzzle: A method of teaching and learning tooth morphology.
European journal of dental education.
ISSN 1396-5883.
s. 1–6.
doi:
10.1111/eje.12403.
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Tulek, Amela; Saeed, Muhammad; Mulic, Aida; Stenhagen, Kjersti Refsholt; Utheim, Tor Paaske & Galtung, Hilde
[Vis alle 10 forfattere av denne artikkelen]
(2018).
New animal model of extrinsic dental erosion-Erosive effect on the mouse molar teeth.
Archives of Oral Biology.
ISSN 0003-9969.
96,
s. 137–145.
doi:
10.1016/j.archoralbio.2018.08.013.
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Objective
Consumption of acidic food and drinks is considered as important risk factor for development of dental erosion. There are several in vitro and in situ studies focusing on the risk indicators and preventive treatment, however, the need for a standardized animal model has been emphasised for many years. The aim was to establish an animal model of extrinsic dental erosion, which may serve as a standard for future studies to improve our understanding of the erosion.
Design
Two acidic drinks, sports drink and cola drink, were given to young mice for six weeks. Experimental and control (water) molars and incisors were dissected out and observed by scanning electron microscopy (SEM). Mandibular first molars were subsequently ground transversely and observed again by SEM. The tooth height and enamel thickness were measured on the SEM images.
Results
The lingual surface of the mandibular molars was most eroded after consumption of acidic drinks. The cola drink exhibited higher erosive effect on mandibular molars compared to sports drink. The lingual tooth height, compared to control, was about 34% and 18% lower in the cola drink and sports drink molars, respectively. Compared to the control molars, the lingual enamel was about 23% thinner in the sports drink molars and totally eroded on the certain lingual areas of the cola drink molars.
Conclusions
This new animal model of extrinsic dental erosion and the presented method with ground molars observed in SEM are suitable for further studies, which will gain deeper insights into the erosive disease.
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Nirvani, Minou; Khuu, Cuong; Tulek, Amela; Utheim, Tor Paaske; Sand, Lars Peter & Snead, Malcolm L.
[Vis alle 7 forfattere av denne artikkelen]
(2018).
Transcriptomic analysis of MicroRNA expression in enamel-producing cells.
Gene.
ISSN 0378-1119.
doi:
10.1016/j.gene.2018.11.089.
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There is little evidence for the involvement of microRNAs (miRNAs) in the regulation of circadian rhythms during enamel development. Few studies have used ameloblast-like cell line LS8 to study the circadian rhythm of gene activities related to enamel formation. However, the transcriptomic analysis of miRNA expression in LS8 cells has not been established yet. In this study, we analyze the oscillations of miRNAs in LS8 cells during one-day cycle of 24 h by next generation deep sequencing. After removal of low quality reads, contaminants, and ligation products, we obtained a high number of clean reads in all 12 samples from four different time points. The length distribution analysis indicated that 77.5% of clean reads were between 21 and 24 nucleotides (nt), of which 35.81% reads exhibited a length of 22 nt. In total, we identified 1471 miRNAs in LS8 cells throughout all four time-points. 1330 (90.41%) miRNAs were identified as known miRNA sequences, whereas 139 (9.59%) were unannotated and classified as novel miRNA sequences. The differential expression analysis showed that 191 known miRNAs exhibited significantly (P-value < 0.01) different levels of expression across three time-points investigated (T6, T12, and T18) compared to T0. Verification of sequencing data using qRT-PCR on six selected miRNAs suggested good correlation between the two methods. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis revealed significant enrichment of predicted target genes of differentially expressed miRNAs. The present study shows that miRNAs are highly expressed in LS8 cells and that a significant number of them oscillate during one-day cycle of 24 h. This is the first transcriptomic analysis of miRNAs in ameloblast-like cell line LS8 that can be potentially used to further characterize the epigenetic regulation of miRNAs during enamel formation.
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Nirvani, Minou; Khuu, Cuong; Utheim, Tor Paaske; Sand, Lars Peter & Sehic, Amer
(2017).
Circadian clock and oral cancer (Review).
Molecular and Clinical Oncology.
ISSN 2049-9450.
doi:
10.3892/mco.2017.1518.
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Sehic, Amer; Tulek, Amela; Khuu, Cuong; Nirvani, Minou; Sand, Lars Peter & Utheim, Tor Paaske
(2017).
Regulatory roles of MicroRNSa in human dental tissues.
Gene.
ISSN 0378-1119.
s. 9–18.
doi:
10.1016/j.gene.2016.10.009.
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Sehic, Amer; Tulek, Amela; Khuu, Cuong; Nirvani, Minou; Sand, Lars Peter & Utheim, Tor Paaske
(2017).
Regulatory roles of microRNAs in human dental tissues.
Gene.
ISSN 0378-1119.
596,
s. 9–18.
doi:
10.1016/j.gene.2016.10.009.
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Utheim, Tor Paaske; Islam, Rakibul; Fostad, Ida Grunnan; Eidet, Jon Roger; Sehic, Amer & Olstad, Ole Kristoffer
[Vis alle 10 forfattere av denne artikkelen]
(2016).
Storage temperature alters the expression of differentiation-related genes in cultured oral keratinocytes.
PLOS ONE.
11(3).
doi:
10.1371/journal.pone.0152526.
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Purpose:
Storage of cultured human oral keratinocytes (HOK) allows for transportation of cultured transplants to eye clinics worldwide. In a previous study, one-week storage of cultured HOK was found to be superior with regard to viability and morphology at 12°C compared to 4°C and 37°C. To understand more of how storage temperature affects cell phenotype, gene expression of HOK before and after storage at 4°C, 12°C, and 37°C was assessed.
Materials and Methods:
Cultured HOK were stored in HEPES- and sodium bicarbonate-buffered Minimum Essential Medium at 4°C, 12°C, and 37°C for one week. Total RNA was isolated and the gene expression profile was determined using DNA microarrays and analyzed with Partek Genomics Suite software and Ingenuity Pathway Analysis. Differentially expressed genes (fold change > 1.5 and P < 0.05) were identified by one-way ANOVA. Key genes were validated using qPCR.
Results:
Gene expression of cultures stored at 4°C and 12°C clustered close to the unstored control cultures. Cultures stored at 37°C displayed substantial change in gene expression compared to the other groups. In comparison with 12°C, 2,981 genes were differentially expressed at 37°C. In contrast, only 67 genes were differentially expressed between the unstored control and the cells stored at 12°C. The 12°C and 37°C culture groups differed most significantly with regard to the expression of differentiation markers. The Hedgehog signaling pathway was significantly downregulated at 37°C compared to 12°C.
Conclusion:
HOK cultures stored at 37°C showed considerably larger changes in gene expression compared to unstored cells than cultured HOK stored at 4°C and 12°C. The changes observed at 37°C consisted of differentiation of the cells towards a squamous epithelium-specific phenotype. Storing cultured ocular surface transplants at 37°C is therefore not recommended. This is particularly interesting as 37°C is the standard incubation temperature used for cell culture.
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Khuu, Cuong; Utheim, Tor Paaske & Sehic, Amer
(2016).
The three paralogous microRNA clusters in development and disease - miR-17-92, miR-106a-363, and miR-106b-25.
Scientifica.
2016.
doi:
10.1155/2016/1379643.
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MicroRNAs (miRNAs) form a class of noncoding RNA genes whose products are small single-stranded RNAs that are involved in the regulation of translation and degradation of mRNAs. There is a fine balance between deregulation of normal developmental programs and tumor genesis. An increasing body of evidence suggests that altered expression of miRNAs is entailed in the pathogenesis of human cancers. Studies in mouse and human cells have identified the miR-17-92 cluster as a potential oncogene. The miR-17-92 cluster is often amplified or overexpressed in human cancers and has recently emerged as the prototypical oncogenic polycistron miRNA. The functional analysis of miR-17-92 is intricate by the existence of two paralogues: miR-106a-363 and miR-106b-25. During early evolution of vertebrates, it is likely that the three clusters commenced via a series of duplication and deletion occurrences. As miR-106a-363 and miR-106b-25 contain miRNAs that are very similar, and in some cases identical, to those encoded by miR-17-92, it is feasible that they regulate a similar set of genes and have overlapping functions. Further understanding of these three clusters and their functions will increase our knowledge about cancer progression. The present review discusses the characteristics and functions of these three miRNA clusters
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Utheim, Tor Paaske; Utheim, Øygunn Aass; Khan, Qalbi & Sehic, Amer
(2016).
Culture of Oral Mucosal Epithelial Cells for the Purpose of Treating Limbal Stem Cell Deficiency.
Journal of Functional Biomaterials.
doi:
10.3390/jfb7010005.
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The cornea is critical for normal vision as it allows allowing light transmission to the retina. The corneal epithelium is renewed by limbal epithelial cells (LEC), which are located in the periphery of the cornea, the limbus. Damage or disease involving LEC may lead to various clinical presentations of limbal stem cell deficiency (LSCD). Both severe pain and blindness may result. Transplantation of cultured autologous oral mucosal epithelial cell sheet (CAOMECS) represents the first use of a cultured non-limbal autologous cell type to treat this disease. Among non-limbal cell types, CAOMECS and conjunctival epithelial cells are the only laboratory cultured cell sources that have been explored in humans. Thus far, the expression of p63 is the only predictor of clinical outcome following transplantation to correct LSCD. The optimal culture method and substrate for CAOMECS is not established. The present review focuses on cell culture methods, with particular emphasis on substrates. Most culture protocols for CAOMECS used amniotic membrane as a substrate and included the xenogeneic components fetal bovine serum and murine 3T3 fibroblasts. However, it has been demonstrated that tissue-engineered epithelial cell sheet grafts can be successfully fabricated using temperature-responsive culture surfaces and autologous serum. In the studies using different substrates for culture of CAOMECS, the quantitative expression of p63 was generally poorly reported; thus, more research is warranted with quantification of phenotypic data. Further research is required to develop a culture system for CAOMECS that mimics the natural environment of oral/limbal/corneal epithelial cells without the need for undefined foreign materials such as serum and feeder cells.
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Utheim, Tor Paaske; Salvanos, Panagiotis; Utheim, Øygunn Aass; Ræder, Sten; Pasovic, Lara & Olstad, Ole Kristoffer
[Vis alle 8 forfattere av denne artikkelen]
(2016).
Transcriptome Analysis of Cultured Limbal Epithelial Cells on an Intact Amniotic Membrane following Hypothermic Storage in Optisol-GS.
Journal of Functional Biomaterials.
7(1).
doi:
10.3390/jfb7010004.
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The aim of the present study was to investigate the molecular mechanisms underlying activation of cell death pathways using genome-wide transcriptional analysis in human limbal epithelial cell (HLEC) cultures following conventional hypothermic storage in Optisol-GS. Three-week HLEC cultures were stored in Optisol-GS for 2, 4, and 7 days at 4 °C. Partek Genomics Suite software v.6.15.0422, (Partec Inc., St. Louis, MO, USA) was used to identify genes that showed significantly different (P < 0.05) levels of expression following hypothermic storage compared to non-stored cell sheets. There were few changes in gene expression after 2 days of storage, but several genes were differently regulated following 4 and 7 days of storage. The histone-coding genes HIST1H3A and HIST4H4 were among the most upregulated genes following 4 and 7 days of hypothermic storage. Bioinformatic analysis suggested that these two genes are involved in a functional network highly associated with cell death, necrosis, and transcription of RNA. HDAC1, encoding histone deacetylase 1, was the most downregulated gene after 7 days of storage. Together with other downregulated genes, it is suggested that HDAC1 is involved in a regulating network significantly associated with cellular function and maintenance, differentiation of cells, and DNA repair. Our data suggest that the upregulated expression of histone-coding genes together with downregulated genes affecting cell differentiation and DNA repair may be responsible for increased cell death following hypothermic storage of cultured HLEC. In summary, our results demonstrated that a higher number of genes changed with increasing storage time. Moreover, in general, larger differences in absolute gene expression values were observed with increasing storage time. Further understanding of these molecular mechanisms is important for optimization of storage technology for limbal epithelial sheets
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Sehic, Amer; Guo, Shuai; Cho, Kin-Sang; Corroya, Rima Maria; Chen, Dong Feng & Utheim, Tor Paaske
(2016).
Electrical stimulation as a means for improving vision.
American Journal of Pathology.
ISSN 0002-9440.
186(11),
s. 2783–2797.
doi:
10.1016/j.ajpath.2016.07.017.
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Abstract
Evolving research has provided evidence that noninvasive electrical stimulation (ES) of the eye may be a promising therapy for either preserving or restoring vision in several retinal and optic nerve diseases. In this review, we focus on minimally invasive strategies for the delivery of ES and accordingly summarize the current literature on transcorneal, transorbital, and transpalpebral ES in both animal experiments and clinical studies. Various mechanisms are believed to underlie the effects of ES, including increased production of neurotrophic agents, improved chorioretinal blood circulation, and inhibition of proinflammatory cytokines. Different animal models have demonstrated favorable effects of ES on both the retina and the optic nerve. Promising effects of ES have also been demonstrated in clinical studies; however, all current studies have a lack of randomization and/or a control group (sham). There is thus a pressing need for a deeper understanding of the underlying mechanisms that govern clinical success and optimization of stimulation parameters in animal studies. In addition, such research should be followed by large, prospective, clinical studies to explore the full potential of ES. Through this review, we aim to provide insight to guide future research on ES as a potential therapy for improving vision.
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Sidaly, Rivan; Schmalfuss, Andreas Jørn; Skaare, Anne B; Sehic, Amer; Stiris, Tom & Espelid, Ivar
(2016).
Five-minute Apgar score ≤ 5 and molar incisor hypomineralisation (MIH) - a case control study.
BMC Oral Health.
17:25.
doi:
10.1186/s12903-016-0253-5.
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Background: The aetiology of molar incisor hypomineralisation (MIH) is unclear. The asymmetric distribution of MIH in the dentition may indicate that an insult of short duration that affects ameloblasts at a vulnerable stage could be a causative factor. Apgar ≤ 5 at 5 min may indicate asphyxia (hypoxic-ischemic insult) during birth. It was hypnotised that low Apgar score during birth may cause MIH. The present study aimed to examine a possible association between Apgar ≤ 5 at 5 min and the occurrence of MIH. Method: Two study groups were selected for examination. The cases comprised 67 children aged 8–10 years born with Apgar score equal to or below 5 after 5 min. The control group comprised 157 age-matched healthy children. First permanent molars, second primary molars and all permanent incisors were examined in all children. Clinical examination was undertaken by two calibrated examiners and intraoral close-up photographs of the teeth were later evaluated by three calibrated and blinded clinicians. Demarcated opacities, post-eruptive breakdown, atypical restorations and extractions due to MIH, according to the criteria of the European Association of Paediatric Dentistry, were assessed. Results: The prevalence of MIH did not differ between the two groups. A chi-square test failed to confirm any statistically significant relationship between 5-min Apgar scores and MIH occurrence. In addition, there was no statistically significant relationship between the number of affected first permanent molars in cases and controls. Conclusion: There was no association between Apgar ≤ 5 at 5 min and the occurrence of MIH.
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Sehic, Amer; Khuu, Cuong; Utheim, Tor Paaske & Khan, Qalb-E-Saleem
(2015).
MicroRNAs and Tooth Development; Model for Organogenesis?
Journal of Dentistry and Oral Care.
ISSN 2379-1705.
1(2),
s. 1–3.
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Khan, Qalbi & Sehic, Amer
(2015).
Understanding Ameloblastomas Through Tooth Development.
Journal of Dentistry and Oral Care.
ISSN 2379-1705.
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Sehic, Amer; Khan, Qalbi; Khuu, Cuong; Minou, Nirvani & Paaske, Utheim Tor
(2015).
Genetic Control of Enamel Development.
Journal of Dentistry and Oral Care.
ISSN 2379-1705.
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Sehic, Amer; Khuu, Cuong; Utheim, Tor Paaske & Khan, Qalbi
(2015).
MicroRNAs and Tooth Development; Model for Organogenesis?
Journal of Dentistry and Oral Care.
ISSN 2379-1705.
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Khan, Qalb-E-Saleem & Sehic, Amer
(2015).
Understanding Ameloblastomas Through Tooth Development.
Journal of Dentistry and Oral Care.
ISSN 2379-1705.
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Sehic, Amer; Khan, Qalb-E-Saleem; Khuu, Cuong; Nirvani, Minou & Utheim, Tor Paaske
(2015).
Genetic Control of Enamel Development.
Journal of Dentistry and Oral Care.
ISSN 2379-1705.
1(3),
s. 1–3.
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Sehic, Amer; Utheim, Øygunn Aass; Ommundsen, Kristoffer & Utheim, Tor Paaske
(2015).
Pre-Clinical Cell-Based Therapy for Limbal Stem Cell Deficiency.
Journal of Functional Biomaterials.
6,
s. 863–888.
doi:
10.3390/jfb6030863.
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Qalb-E-Saleem, Khan Ahmed; Sehic, Amer; Khuu, Cuong; Risnes, Steinar & Osmundsen, Harald
(2013).
Expression of Clu and Tgfb1 during murine tooth development: effects of in-vivo transfection with anti-miR-214.
European Journal of Oral Sciences.
ISSN 0909-8836.
121(4),
s. 303–312.
doi:
10.1111/eos.12056.
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Expression of clusterin (Clu) in the murine first molar tooth germ was markedly increased at postnatal developmental stages. The time-course of expression of this gene paralleled those of other genes encoding proteins involved during the secretory phase of odontogenesis, as described previously. Immunohistochemical studies of clusterin in murine molar tooth germs suggested this protein to be located in outer enamel epithelium, regressing enamel organ, secretory ameloblasts, and the dental epithelium connecting the tooth to the oral epithelium at an early eruptive stage. Immunolabelling of transforming growth factor beta-1 (TGF-β1) revealed it to be located close to clusterin. The levels of expression of Clu and Tgfb1 were markedly decreased following in-vivo transfection with anti-miR-214. In contrast, the expression of several genes associated with regulation of growth and development were increased by this treatment. We suggest that clusterin has functions during secretory odontogenesis and the early eruptive phase. Bioinformatic analysis after treatment with anti-miR-214 suggested that, whilst cellular activities associated with tooth mineralization and eruption were inhibited, activities associated with an alternative developmental activity (i.e. biosynthesis of contractile proteins) appeared to be stimulated. These changes probably occur through regulation mediated by a common cluster of transcription factors and support suggestions that microRNAs (miRNAs) are highly significant as regulators of differentiation during odontogenesis.
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Sehic, Amer; Risnes, Steinar & Nirvani, Minou
(2013).
Incremental lines in mouse molar enamel.
Archives of Oral Biology.
ISSN 0003-9969.
58(10),
s. 1443–1449.
doi:
10.1016/j.archoralbio.2013.06.013.
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Objective
The purpose of the present study was to investigate the occurrence and periodicity of enamel incremental lines in mouse molars in an attempt to draw attention to some key questions about the rhythm in the activity of the secreting ameloblasts during formation of mouse molar enamel.
Methods
The mouse molars were ground, etched, and studied using scanning electron microscopy.
Results
Lines interpreted as incremental lines generally appeared as grooves of variable distinctness, and were only observed cervically, in the region about 50–250 μm from the enamel–cementum junction. The lines were most readily observable in the outer enamel and in the superficial prism-free layer, and were difficult to identify in the deeper parts of enamel, i.e. in the inner enamel with prism decussation. However, in areas where the enamel tended to be hypomineralized the incremental lines were observed as clearly continuous from outer into inner enamel. The incremental lines in mouse molar enamel exhibited an average periodicity of about 4 μm, and the distance between the lines decreased towards the enamel surface.
Conclusions
We conclude that incremental lines are to some extent visible in mouse molar enamel. Together with data from the literature and theoretical considerations, we suggest that they probably represent a daily rhythm in enamel formation. This study witnesses the layered apposition of mouse molar enamel and supports the theory that circadian clock probably regulates enamel development.
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Sehic, Amer; Risnes, Steinar; Khuu, Cuong; Qalb-E-Saleem, Khan Ahmed & Osmundsen, Harald
(2011).
Effects of in vivo transfection with anti-miR-214 on gene expression in murine molar tooth germ.
Physiological Genomics.
ISSN 1094-8341.
43(9),
s. 488–498.
doi:
10.1152/physiolgenomics.00248.2010.
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Sehic, Amer; Risnes, Steinar; Qalb-E-Saleem, Khan Ahmed; Khuu, Cuong & Osmundsen, Harald
(2010).
Gene expression and dental enamel structure in developing mouse incisor.
European Journal of Oral Sciences.
ISSN 0909-8836.
118(2),
s. 118–130.
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Qalb-E-Saleem, Khan Ahmed; Press, Charles McLean; Sehic, Amer; Landin, Maria Augusta Dos S Silva; Risnes, Steinar & Osmundsen, Harald
(2010).
Expression of prion gene and presence of prion protein during development of mouse molar tooth germ.
European Journal of Oral Sciences.
ISSN 0909-8836.
118(6),
s. 559–565.
doi:
10.1111/j.1600-0722.2010.00783.x.
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Sehic, Amer; Peterkova, Renata; Lesot, Hervé & Risnes, Steinar
(2009).
Distribution and structure of the initial dental enamel formed in incisors of young wild-type and Tabby mice.
European Journal of Oral Sciences.
ISSN 0909-8836.
117(6),
s. 644–654.
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Sehic, Amer; Khuu, Cuong; Risnes, Steinar & Osmundsen, Harald
(2009).
Differential gene expression profiling of the molar tooth germ in peroxisome proliferator-activated receptor-alpha (PPAR-alpha) knockout mouse and in wild-type mouse: molar tooth phenotype of PPAR-alpha knockout mouse.
European Journal of Oral Sciences.
ISSN 0909-8836.
117(2),
s. 93–104.
doi:
10.1111/j.1600-0722.2009.00615.x.
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Kristensen, Anna Tostrup; Thune, Noora Helene; Khan, Qalbi; Utheim, Tor Paaske & Sehic, Amer
(2024).
The Importance of Basic Sciences in Dental Education.
Dentistry Journal.
12(382).
doi:
10.3390/dj12120382.
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The rapid advancements in biomedical sciences, including genomics, microbiome research, and bioinformatics, underscore the need for dental education to evolve to meet future challenges in public oral health and healthcare delivery. The integration of basic sciences into dental curricula is crucial to ensure that dental professionals are thoroughly prepared in these fundamental areas. Despite the widespread agreement on the necessity of including basic medical sciences in dental education, challenges such as curricular congestion, faculty economics, and infrastructural limits persist, complicating the integration of new scientific knowledge. Furthermore, there remains a significant lack of research concerning the optimal extent, timing, and focus of these subjects, whether biochemical, medical, or dental. Additionally, there is a need to address prevailing conceptions about the irrelevance of basic sciences to the field of dentistry, which necessitates a focus on teaching methodologies and pedagogical strategies. Therefore, it is essential to advance educational research that prepares future educators to integrate basic sciences into dental education through evidence-based teaching methods. The dental curriculum, which encompasses fundamental sciences, laboratory exercises, and clinical practice, must overcome considerable pedagogical challenges to effectively incorporate and balance these basic sciences within its educational structure.
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Schmalfuss, Andreas Jörn; Sehic, Amer & Brusevold, Ingvild Johnsen
(2018).
Effects of high-dose antibiotics on developing enamel in neonate mice measured with micro-CT.
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Utheim, Tor Paaske; Utheim, Øygunn Aass; Eidet, Jon Roger; Ræder, Sten; Jackson, Catherine & Sehic, Amer
(2015).
Transplantasjon av hud til øyets overflate. Hva er status 122 år etter første transplantasjon?
Oftalmolog.
ISSN 0108-5344.
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Landin, Maria Augusta Dos S Silva; Ghadakchi, Shabestari Yashar; Sehic, Amer; Reseland, Janne Elin & Osmundsen, Harald
(2014).
MK-7 enhances expression of genes related to bone, enamel and dentin, and reduces the expression of genes related to apoptosis in developing murine molars.
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Khuu, Cuong; Jevnaker, Anne Marthe; Sehic, Amer; Bryne, Magne & Osmundsen, Harald
(2010).
High levels of miR-363*inhibit proliferation of oral carcinoma cell line E10.
European Journal of Cancer.
ISSN 0959-8049.
8(5),
s. 140–141.
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Sehic, Amer; Peterkova, Renata; Lesot, Hervé & Risnes, Steinar
(2010).
P32-distribution and structure of the initial dental enamel formed in incisors of young wild-type and Tabby mice.
Bull Group Int. Rech Sci. Stomatol. Odontol.
49,
s. 104–106.
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Klinge, Randi Furseth; Sehic, Amer; Risnes, Steinar & From, Sigurd Hjalmar
(2004).
The ultrastructure of the enamel of mouse mandibular arch tooth grafts implanted under the kidney capsule.Porceedings 13th European Microscopy Congress, Antwerp, Belgium.
Life Sciences.
ISSN 0024-3205.
III,
s. 449–450.
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Klinge, Randi Furseth; Sehic, Amer & From, Sigurd Hjalmar
(2004).
The structure of the dental tissues of mouse mandibular arch tooth grafts implanted under the kidney capsule.
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Publisert
11. nov. 2010 16:11
- Sist endret
18. mars 2025 12:31
