Numerical investigation of cavitation in periodontal Pockets: Insights for enhancing cleaning efficiency.

Ultrasonic dental scalers are indispensable instruments for efficient dental cleaning through the generation of cavitation. To gain valuable insights and enhance the cavitation cleaning effects, a numerical investigation is conducted using the finite element method via ABAQUS. Numerical results are compared with the experimental cavitation image for a scaler undergoes vibrations near a wall. We then analyse how the amplitude, frequency, and cross-sectional shape of the scaler affect cavitation generation. Numerical results indicate that cavitation is more pronounced for a scaler oscillating near a nearly rigid boundary than a soft boundary. It increases with the vibration amplitude because of higher ultrasonic energy transferring to the liquid and generating stronger pressure waves. The resonant frequency of the scaler coincides with the maximum cavitation and scaler tip amplitude. Reducing the dimension of the cross-section of the scaler in its oscillation direction increases both the scaler tip amplitude and the cavitation generated. This finding offers a potential design approach for enhancing the scaler cavitation and its cleaning effects. These insights provide practical guidance for optimising dental scaler settings, which can improve oral hygiene and prevent complications related to dental implants.

Online videos: The hidden curriculum.

INTRODUCTION: Dental undergraduates will access the Internet searching for learning materials to complement their training; however, open access content is not generally recommended by dental schools. This study aimed to evaluate how dental students are using online video content. MATERIALS AND METHODS: Students from eight Universities (Athens, Birmingham, Brescia, Cardiff, Melbourne, Paris, Sao Paulo and Valdivia) representing three continents were invited to complete a survey on their access and learning from online videos. RESULTS: International students behave similarly when studying dental content online. Of 515 respondents, 94.6% use the Internet as a learning tool. It was observed that videos are not frequently recommended during didactic lectures (9.6%). But many students (79.9%) will use YouTube for their learning which includes clinical procedures. Students will check online content before performing procedures for the first time (74.8%), to understand what was explained in class (65.9%) or read in books (59.5%), to relearn clinical techniques (64.7%) and to visualise rare procedures (49.8%). More than half of the students do not fully trust the accuracy or the reliability of online content. This does not prevent students from watching and sharing dental videos with classmates (64.4%). The content watched is not shared with teachers (23.3%) even when it contradicts what was learnt in the school (38.2%). CONCLUSION: This study concludes that students regularly integrate open access digital resources into learning portfolios but are hesitant to inform their teachers about their viewing habits. Students wish to receive critical skills on how to evaluate the material they encounter outside their traditional learning space.

Using quizzes to provide an effective and more enjoyable dental education: A pilot study.

INTRODUCTION: Increasingly, dental education is using digital strategies to deliver teaching; however, not all of these learning materials are engaging and effective. AIM: To evaluate the perception and knowledge retention of undergraduate dental students after using two different digital learning tools: quizzes and PDF. METHODS: Thirty-three students from a Dental School in the United Kingdom took part in the research. They received learning material derived from the Prosthodontic (Kennedy classification) or Paediatric dentistry content (Tooth classification). The same content was delivered in two different formats: quiz game (n = 17) and PDF file (n = 16). The PDF file had ten images and their classifications, whilst the quiz had the same images with a question about the classification, along with alternatives (single best answer). RESULTS: All students gave similar performances on the knowledge assessment; however, their perception about the learning material differed. Students using quizzes (88%) agreed that they were fun and an interesting way of learning, while only 37.5% had this opinion about PDF material (p = .002). When using quizzes, learners were more motivated and confident. They would frequently recommend quizzes to other colleagues; however, the use of PDF was not suggested as frequently (p = .039). As a learning strategy, 100% of the students using quizzes wanted more of the same to study other dental subjects. This was not the case with the PDF format (p = .005). CONCLUSION: Despite quizzes and PDF files resulting in a similar understanding of dental subjects, learners prefer quizzes to supplement their studies. Educators should consider using this interactive digital tool to engage students, instead of PDF files.

A critical review of qualitative research publications in dental implants from 2006 to 2020.

OBJECTIVES: This critical review is aimed to investigate the current status of qualitative research in dental implant research and to explore the quality of available information. MATERIAL AND METHODS: A systematic search was done on the journal databases to identify dental implant research articles that used qualitative methodology during 2006 and 2020. The resulting articles were appraised against the checklist offered by the Critical Appraisal Skills programme (CASP) tool. Also, the theories evolved from the research were reviewed to understand the value of this methodology in dental implant research. RESULTS: Twenty-five (25) articles out of the 8,421 original results were identified as using qualitative methodology. The researchers have sought to identify the views of patients about tooth loss, dental implants, and the information they receive from dental professionals, and views of the dentists about dental implant practice. The review found that there were few inconsistencies in the quality of such research especially the qualitative data analysis. CONCLUSIONS: The quantity of qualitative research in dental implants remains low; however, the quality has improved in the past two decades. Despite these improvements, there is still a lack of research in understanding both patients' and dentists' views on dental implant procedures and management.

Challenges in dental implant provision and its management in general dental practice.

OBJECTIVES: Dental implants have become a well-publicised treatment modality in dentistry. Implants are generally placed in the private sector by dentists who have undertaken further learning. The continued maintenance of implants falls within the duty of care for the general dental practitioner. The objective of this qualitative study is to investigate the current status of dental implants in general dental practice, and to explore the dentists view on dental implant education at both undergraduate and postgraduate level. METHODS: In-depth interviews as a qualitative methodology was used in the study. The participants were recruited through theoretical sampling guided by saturation of information. Based on this, 22 general dental practitioners practicing in the UK were interviewed. Transcribed interview data were coded with NVIVO software and then analysed using a thematic framework analysis method. RESULTS: General dentists from different educational backgrounds, experience levels participated in the study. They highlighted that the guidelines and protocols when dealing with implants were unclear and expressed their unwillingness to treat patients who had their specialised dental treatment performed elsewhere. CONCLUSION: Expensive dental implant treatment is not being followed up by the general dental practitioner due to a wide range of barriers. Unclear care paths will lead to a likely increase in problems following implant placement. CLINICAL SIGNIFICANCE: General Dentists' views of dental implants in general practice and their expectations from education providers are explored and show the need for improved education.

Simulation training for ceramic crown preparation in the dental setting using a virtual educational system.

OBJECTIVES: The aim was to evaluate the effectiveness of a pre-clinical training of ceramic crown preparation using the Virtual Educational System for Dentistry. MATERIAL AND METHODS: Fifty-seven dental students were recruited to prepare a ceramic crown under the guidance of the Real-time Dental Training and Evaluation System (RDTES) in order to collect pre-learning data. They participated in the online virtual learning course independently on the Virtual Learning Network Platform (VLNP). One week later, the students were invited to complete their post-learning crown preparation with the RDTES. A questionnaire survey explored students' perceived benefits or drawbacks of the virtual educational system. Students were allocated into Group A (n = 15), B (n = 24) and C (n = 18) based on their pre-learning performance. Differences of assessment results amongst different groups were evaluated by ANOVA and Kruskal-Wallis tests. The pre- and post-learning assessment results in all groups were compared using paired t tests or Wilcoxon signed rank tests. RESULTS: The error scores for four assessment items (instrument selection, preparation section, preparation reduction, preparation surface and profile) and total score of outcome assessment after the virtual learning were significantly different with those before the virtual learning (P < 0.05). There were significant interactions between time and student group in the mean scores of process and outcome assessments (P < 0.001), except for the assessment item "damage of adjacent teeth." CONCLUSION: The application of a Virtual Educational System for Dentistry with the VLNP and RDTES in pre-clinical operative training helps students improve their clinical skills.

Games in dental education: playing to learn or learning to play?

Learners are motivated when using games and they have been successfully introduced in many healthcare subjects such as medicine and nursing. The development of games in dentistry has not kept pace with their uptake both as a popular pastime and their implementation in other subjects. Games in the learning space have many advantages. Several scenarios can be gamified in pre-clinical and clinical practice creating an enjoyable learning experience for both undergraduate and postgraduate students. The aim of this article is to enthuse educators on the potential of games and offer practical suggestions on how to implement them in their teaching.

The availability of open-access videos offered by dental schools.

BACKGROUND: The Internet has become an established learning tool in dental education where students can access online videos on a range of dental subjects. However, finding reliable peer-reviewed content is not straightforward. AIM: To evaluate the video content offered by UK and Republic of Ireland (RoI) Dental Schools on their YouTube channels and public websites. METHODS: Free videos offered on UK and RoI Dental schools websites and YouTube channels were watched and set according to its purpose, as educational or non-educational. The number of views, length, category and date of publication were analysed. RESULTS: A total of 627 videos offered by dental courses were evaluated. Videos were available on 83% of the websites, but only 9% was educational content. Dental courses YouTube channels received more than 2.3 million views, but less than 5% of the material offered is educational. Instructional videos found on the websites (3.2 min) were shorter than those found on YouTube (8.5 min) (P = .03). The majority of the videos, provided by Universities, were not educational and focused on promoting the dental courses. Most websites have demonstrated a password-protected area where quality content may be offered. CONCLUSION: Students wishing to watch instructional videos will find limited educational content provided by UK and RoI dental courses. Therefore, they are likely to access course-related material elsewhere on the Internet that may not be necessarily peer-reviewed.

Mobile learning in dentistry: challenges and opportunities.

Introduction The impact of smartphone technology is changing the approach to learning and teaching in clinical dental education. The aim of this study was to understand the challenges, opportunities and attitudes that both dental undergraduate students in an English dental school and tutors experience when using electronic learning.Materials and methods Six faculty members and 20 students agreed to take part in semi- structured interviews. Topic question guides for the student interviews focused on searching for information and how they used mobile learning. Questions also asked about the barriers encountered when accessing information on the internet, their perspective on the term 'evidence-based' information, and their use of mobile apps. The question topic guide for faculty was similar, with an emphasis on their attitudes to the introduction of such technology in dental education.Results Both groups reported active use of mobile learning tools. However, students are in need of training and further guidance when searching for, evaluating and synthesising evidence-based information online. Likewise, tutors need to become familliar with e-learning tools so that they may better support their students.Conclusion The results from the study show that participants need training workshops to ensure that students are not only accessing evidence-based information, but can differentiate between evidence-based and non-evidence-based information apps. The tutors in this study also require information on how to provide their students with advice on using mobile technology. Institutions involved with clinical dentistry should acknowledge such challenges.

Fake news and dental education.

Fake news is used to spread disinformation on many subjects with the aim of distorting the truth. There has been a rise of fake news stories in dentistry such as homemade whitening products and misinformed information on how to strengthen your teeth. Such stories populate YouTube and other social media. Evidence-based dentistry does not provide all the answers, so patients and health professions readily seek out information that confirms their own views on the subject. There are tools available that may be used to verify the accuracy of such information and help to dispel fake news. The ideal way to deal with the influence of fake news is to empower individuals to publish and create an environment of 'real news'.

Who is providing dental education content via YouTube?

Introduction Online video sharing platforms are regularly visited by dental students. However, they may be accessing non-peer-reviewed content which is not officially recommended by their dental school's curriculum.Aims To evaluate the reliability of dental education content found on YouTube.Methods A YouTube search for dental procedures content was conducted using the keywords 'restorative dentistry', 'paediatric dentistry', 'orthodontics' and 'oral surgery'. The first ten results of each search were set according to its publisher. The number of views, length, category, retention index and date of publication were analysed.Results Around 70% of the videos were published under education/science categories. These 40 videos received 25 million visitors and showed an average length of 9.22 min (± 8.19). Universities provided only 5% of the content. Older videos had more views per month (p <0.05) and a better interaction index (p >0.05). Most users preferred the long videos (p <0.05) and the interaction index was better for those older videos (p <0.01). Short videos had 70% user retention, while ten-minute-long videos had 21%.Conclusions Most of the content found did not match the reliability criteria. Universities should consider how their students use YouTube and look to incorporate their findings into their curriculum. Content length and more recent dental videos will influence student retention and learning.

Femtosecond laser ablation of dentin and enamel for fast and more precise dental cavity preparation.

PURPOSE: The purpose of the present work was to achieve fast and more precise ablation in dentin and enamel by using a commercial femtosecond laser system with high repetition rate, whilst avoiding any collateral irreversible damages in the hard tissue and pulp area. METHODS: We used fluence of the incident laser pulses which was marginally higher than the ablation threshold for dentin and enamel. The study was based on the hypothesis that femtosecond laser operating with a repetition rate in the range of 100-500 kHz can controllably ablate dental tissue obtaining sufficiently high removal rate whilst avoiding any collateral irreversible damages in the hard tissue and pulp area. RESULTS: The ablation yielded the formation of 1 mm3 craters with well-defined precise vertical cavity sides and edges. Advantageous high porosity and numerous interconnected pores were introduced in the ablated zones. Thermal load and hence collateral thermo-mechanical damages were avoided and the crystalline structure of the tooth constituent hydroxyapatite was preserved. CONCLUSION: The ultrafast femtosecond laser used in our work hold the promise of a significant drilling ability without collateral thermomechanical effects. It achieves high processing efficiency, overcomes disadvantages of other laser systems reported and can be used to develop an instrument for cavity preparation based on fast and precise ablation. Our further aim is to exceed the speed of traditional drilling instruments and thus to reduce the treatment time which in turn will bring comfort to the patient.

Evidence-Based Dentistry in Everyday Practice.

This article informs readers of a method of implementing evidence-based dentistry in practice. Following these steps, practitioners should be able to use this skill in an efficient manner. The importance of evidence-based dentistry and its relevance to situations encountered in everyday practice is also highlighted. Clinical relevance: This article highlights a series of steps to be followed by practitioners to ensure that treatment provided is supported by the most recent, good quality evidence.

The deposition and imaging of silica sub-micron particles in dentine.

OBJECTIVES: Sub-micron particles may assist in the delivery of compounds into dentine tubules. The surface interactions of the particles with dentine may prevent them from entering the tubules. The aim of this study is to investigate whether silica particles, treated with surfactants improves dentine tubules occlusion using both artificial and human tooth models METHODS: Spherical silica particles (size 130-810nm) bearing an encapsulated ruthenium luminescent complex were coated with the following surfactants: Zonyl(®) FSA, Triton(®) X-100 and Tween20(®). The particles were prepared as 0.004% w/v and 0.04% w/v solutions with deionized water and were applied to the surface of; (1) in vitro model of PET ThinCert™ cell culture inserts; (2) 0.1mm thick sections of human molar teeth. RESULTS: Scanning electron and confocal fluorescence microscopy images show that particles without any coating and with TritonX-100 coating had the highest aggregation. Particles with Tween-20 are less aggregated on the surface and show inclusion in the tubules. Particles coated with fluorosurfactant Zonyl show a preference for aggregation at the tubule. With the ThinCert™ membranes high aggregation within the artificial tubules was increased by particle concentration. CONCLUSIONS: The use of silica sub-micron particles on hard dental tissues is dependent on the modification of the surface chemistry of both the particle and the dentine and the employment of the fluorοsurfactant may improve tubule occlusion. The use of ThinCerts™ membrane is useful in vitro model to mimic dentinal tubules and observe the ability of particles to occlude small channels. CLINICAL SIGNIFICANCE: The use of silica sub-micron particles on hard dentine tissues is dependent on the modification of the surface coating of the particles. This may influence how particles are incorporated in potential delivery vehicles applied to the dentine surface with the employment of a fluorosurfactant showing promise.

AWARE-AWAreness during REsuscitation-a prospective study.

BACKGROUND: Cardiac arrest (CA) survivors experience cognitive deficits including post-traumatic stress disorder (PTSD). It is unclear whether these are related to cognitive/mental experiences and awareness during CPR. Despite anecdotal reports the broad range of cognitive/mental experiences and awareness associated with CPR has not been systematically studied. METHODS: The incidence and validity of awareness together with the range, characteristics and themes relating to memories/cognitive processes during CA was investigated through a 4 year multi-center observational study using a three stage quantitative and qualitative interview system. The feasibility of objectively testing the accuracy of claims of visual and auditory awareness was examined using specific tests. The outcome measures were (1) awareness/memories during CA and (2) objective verification of claims of awareness using specific tests. RESULTS: Among 2060 CA events, 140 survivors completed stage 1 interviews, while 101 of 140 patients completed stage 2 interviews. 46% had memories with 7 major cognitive themes: fear; animals/plants; bright light; violence/persecution; deja-vu; family; recalling events post-CA and 9% had NDEs, while 2% described awareness with explicit recall of 'seeing' and 'hearing' actual events related to their resuscitation. One had a verifiable period of conscious awareness during which time cerebral function was not expected. CONCLUSIONS: CA survivors commonly experience a broad range of cognitive themes, with 2% exhibiting full awareness. This supports other recent studies that have indicated consciousness may be present despite clinically undetectable consciousness. This together with fearful experiences may contribute to PTSD and other cognitive deficits post CA.

X-ray scattering evaluation of ultrastructural changes in human dental tissues with thermal treatment.

Micro- and ultrastructural analysis of burned skeletal remains is crucial for obtaining a reliable estimation of cremation temperature. Earlier studies mainly focused on heat-induced changes in bone tissue, while this study extends this research to human dental tissues using a novel quantitative analytical approach. Twelve tooth sections were burned at 400-900°C (30-min exposure, increments of 100°C). Subsequent combined small- and wide-angle X-ray scattering (SAXS/WAXS) experiments were performed at the Diamond Light Source synchrotron facility, where 28 scattering patterns were collected within each tooth section. In comparison with the control sample, an increase in mean crystal thickness was found in burned dentine (2.8-fold) and enamel (1.4-fold), however at a smaller rate than reported earlier for bone tissue (5-10.7-fold). The results provide a structural reference for traditional X-ray scattering methods and emphasize the need to investigate bone and dental tissues separately to obtain a reliable estimation of cremation temperature.

Multiscale modelling and diffraction-based characterization of elastic behaviour of human dentine.

Human dentine is a hierarchical mineralized tissue with a two-level composite structure, with tubules being the prominent structural feature at a microlevel, and collagen fibres decorated with hydroxyapatite (HAp) crystallite platelets dominating the nanoscale. Few studies have focused on this two-level structure of human dentine, where the response to mechanical loading is thought to be affected not only by the tubule volume fraction at the microscale, but also by the shape and orientation distribution of mineral crystallites, and their nanoscale spatial arrangement and alignment. In this paper, in situ elastic strain evolution within HAp in dentine subjected to uniaxial compressive loading along both longitudinal and transverse directions was characterized simultaneously by two synchrotron X-ray scattering techniques: small- and wide-angle X-ray scattering (SAXS and WAXS, respectively). WAXS allows the evaluation of the apparent modulus linking the external load to the internal HAp crystallite strain, while the nanoscale HAp distribution and arrangement can be quantified by SAXS. We proposed an improved multiscale Eshelby inclusion model that takes into account the two-level hierarchical structure, and validated it with a multidirectional experimental strain evaluation. The agreement between the simulation and measurement indicates that the multiscale hierarchical model developed here accurately reflects the structural arrangement and mechanical response of human dentine. This study benefits the comprehensive understanding of the mechanical behaviour of hierarchical biomaterials. The knowledge of the mechanical properties related to the hierarchical structure is essential for the understanding and predicting the effects of structural alterations that may occur due to disease or treatment on the performance of dental tissues and their artificial replacements.

Humeral epiphyseal shape in the felidae: the influence of phylogeny, allometry, and locomotion.

Bone morphology of the cats (Mammalia: Felidae) is influenced by many factors, including locomotor mode, body size, hunting methods, prey size and phylogeny. Here, we investigate the shape of the proximal and distal humeral epiphyses in extant species of the felids, based on two-dimensional landmark configurations. Geometric morphometric techniques were used to describe shape differences in the context of phylogeny, allometry and locomotion. The influence of these factors on epiphyseal shape was assessed using Principal Component Analysis, Linear Discriminant functions and multivariate regression. Phylogenetic Generalised Least Squares was used to examine the association between size or locomotion and humeral epiphyseal shape, after taking a phylogenetic error term into account. Results show marked differences in epiphyseal shape between felid lineages, with a relatively large phylogenetic influence. Additionally, the adaptive influences of size and locomotion are demonstrated, and their influence is independent of phylogeny in most, but not all, cases. Several features of epiphyseal shape are common to the largest terrestrial felids, including a relative reduction in the surface area of the humeral head and increased robusticity of structures that provide attachment for joint-stabilising muscles, including the medial epicondyle and the greater and lesser tubercles. This increased robusticity is a functional response to the increased loading forces placed on the joints due to large body mass.

Recovering incomplete data using Statistical Multiple Imputations (SMI): a case study in environmental chemistry.

This paper presents a statistical technique that can be applied to environmental chemistry data where missing values and limit of detection levels prevent the application of statistics. A working example is taken from an environmental leaching study that was set up to determine if there were significant differences in levels of leached arsenic (As), chromium (Cr) and copper (Cu) between lysimeters containing preservative treated wood waste and those containing untreated wood. Fourteen lysimeters were setup and left in natural conditions for 21 weeks. The resultant leachate was analysed by ICP-OES to determine the As, Cr and Cu concentrations. However, due to the variation inherent in each lysimeter combined with the limits of detection offered by ICP-OES, the collected quantitative data was somewhat incomplete. Initial data analysis was hampered by the number of 'missing values' in the data. To recover the dataset, the statistical tool of Statistical Multiple Imputation (SMI) was applied, and the data was re-analysed successfully. It was demonstrated that using SMI did not affect the variance in the data, but facilitated analysis of the complete dataset.

Combining self-modeling curve resolution methods and partial least squares to develop a quantitative reaction monitoring method with minimal reference data.

An example of combining self-modeling curve resolution (SMCR) methods and partial least squares (PLS) to construct a quantitative model using minimal reference data is presented. The objective was to construct a quantitative calibration model to allow real-time in situ ultraviolet-attenuated total reflection (UV/ATR) measurements to determine the end-point during a chlorination reaction. Time restrictions for development combined with difficult reaction sampling conditions required the method to be developed using only a few key reference measurements. Utilizing evolving factor analysis (EFA) and the orthogonal projection approach (OPA), initial estimates of the concentration and spectral profiles for the intermediate and product were obtained. Further optimization by multivariate curve resolution-alternating least squares (MCR-ALS) led to refined estimates of the concentration profiles. A PLS2 model was then constructed using the calculated concentration profiles and the preprocessed UV spectra. Using a standard PLS model compatible with the spectrometer's standard process software facilitated real-time predictions for new batches. This method was applied to five 45 liter batches in a large-scale laboratory facility. The method successfully predicted the product concentration of batch 1 but exhibited larger prediction error for subsequent batches. The largest prediction error was attained during batch 3, for which a final concentration of 0.22 mole L(-1) was predicted, while the true measured value was 0.271 mole L(-1) (an error of 18.8%). However, the qualitative real-time profiles proved to be extremely useful as they allowed the end-point to be determined without sampling or performing off-line analysis. Furthermore, the concentration profile of the intermediate species, which could not be observed by the offline method, could also be observed in real-time and gave further confidence that the process was approaching the end-point. Another benefit of real-time reaction profiles was encountered during the manufacture when the formation of product in batch 3 appeared to be progressing slower than was observed in previous batches. This prompted a check of the batch temperature and it was found to be 10 degrees C lower than the required set-point. The temperature was corrected and the batch successfully reached completion in the expected time.