Onset and progression of dental erosion in a mouse model.

OBJECTIVE: Purpose of this research was to examine the onset, progression and wear rates of dental erosion in an established mouse model. 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.  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. 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.

Integrating Structured Digital Tools with the Traditional Hands-on Puzzle Method for Teaching Tooth Morphology: A Comparative Study of Educational Outcomes.

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.

Accumulation and removal of Streptococcus mutans biofilm on enamel and root surfaces in vitro.

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. 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). 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. 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.

Do Bicycle Helmets Protect Against Facial Fractures? An Observational Study From a Level 1 Trauma Centre.

This study investigates the impact of helmet use on the incidence of facial fractures in bicycle accidents. Analyzing data from hospitalized bicyclists between 2005 and 2016, the research focused on the correlation between helmet usage and various facial fractures. The study included 1256 bicyclists with known helmet use, among whom 277 individuals (22%) were identified with a total of 521 facial fractures. The findings revealed a significant reduction in the likelihood of facial fractures among helmeted cyclists compared with those without helmets (odds ratio, 0.65; confidence interval, 0.50-0.85; P=0.002). Specifically, the odds of sustaining fractures in the zygoma, orbit, nose, and maxilla were decreased by 47%, 46%, 43%, and 33%, respectively, among helmeted cyclists. However, helmet use did not significantly alter the odds of mandible fractures. Overall, the use of helmets in bicycling significantly lowered the risk of midface fractures but showed no notable effect on mandible fractures in severe cycling incidents.

Traditional Hands-On Puzzle Method versus Fully Digital Approach in Teaching Tooth Morphology: A Comparative Study of Educational Outcomes.

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.

Different Methods of Teaching and Learning Dental Morphology.

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.

The association between head injury and facial fracture treatment: an observational study of hospitalized bicyclists from a level 1 trauma centre.

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.

Association of Locus Xq26.1-27.3 with Erosive Tooth Wear Phenotypes in a Group of Adolescents.

Erosive tooth wear is a multifactorial condition of an increasing prevalence. There is a need for discovering individual genetic predisposition for the development of this condition. Considering that the chromosome X locus was previously shown to be associated with dental caries, the aim of the present study was to look for the association between this locus and erosive tooth wear when dietary habits are considered as a co-factor. Saliva samples, erosive wear experience data, and dietary information from 16- to 18-year-old dental patients (n = 705) were used. Genotyping analyses were performed, and thereafter, analyses considering diet and oral hygiene data, using logistic regression, with the assumption that erosive tooth wear is a complex gene-environment model. Genotypic analyses revealed an association between chromosome X marker rs1324156 and erosive tooth wear phenotype. Logistic regression analysis showed that, in the presence of less common allele of rs12687601 and rs1324156, erosive tooth wear more likely develops when associated with numerous dietary variables from the questionnaire. These results indicate that erosive tooth wear may be the result of gene-environment interactions.

Facial Fractures and Their Relation to Head and Cervical Spine Injuries in Hospitalized Bicyclists.

Bicyclists are vulnerable road users. The authors aimed to characterise facial fractures and their association with head and neck injuries in bicyclists admitted to a Scandinavian Level 1 trauma center with a catchment area of ~3 million inhabitants. Data from bicycle-related injuries in the period 2005 to 2016 were extracted from the Oslo University Hospital trauma registry. Variables included were age; sex; date of injury; abbreviated injury scale (AIS) codes for facial skeletal, head and neck injuries; and surgical procedure codes for treatment of facial fractures. Anatomical injury was classified according to AIS98. A total of 1543 patients with bicycle-related injuries were included. The median age was 40 years (quartiles 53, 25), and 1126 (73%) were men. Overall, 652 fractures were registered in 339 patients. Facial fractures were observed in all age groups; however, the proportion rose with increasing age. Bicyclists who suffered from facial fractures more often had a concomitant head injury (AIS head >1) than bicyclists without facial fractures (74% vs. 47%), and the odds ratio for facial fracture(s) in the orbit, maxilla and zygoma were significantly increased in patients with AIS head >1 compared to patients with AIS head=1. In addition, 17% of patients with facial fractures had a concomitant cervical spine injury versus 12% of patients without facial fractures. This results showed that facial fractures were common among injured bicyclists and associated with both head and cervical spine injury. Thus, a neurological evaluation of these patients are mandatory, and a multidisciplinary team including maxillofacial and neurosurgical competence is required to care for these patients.

Anatomical distribution of mandibular fractures from severe bicycling accidents: A 12-year experience from a Norwegian level 1 trauma center.

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.