Project description:The repeatability of a non-invasive digital protocol proposed to evaluate the three-dimensional (3D) position of the occlusal plane in the face is assessed. Dental virtual models and soft tissue facial morphology of 20 adult subjects were digitally integrated using a 3D stereophotogrammetric imaging system. The digital 3D coordinates of facial and dental landmarks were obtained by two different operators. Camper's (facial) and occlusal (dental) planes were individuated, and their 3D relationships were measured. The repeatability of the protocol was investigated and showed no significant differences in repeated digitizations. The angle between occlusal and Camper's planes was smaller than 2° in the frontal and horizontal projections. In the sagittal projection, the angle was observed to be, on average, 4.9°. The determined occlusal plane pitch, roll and yaw values show good agreement with previously published data obtained by different protocols. The current non-invasive method was repeatable, without inter-operator differences and can facilitate assessment of healthy subjects.
Project description:<h4>Background</h4>Hypsodont equine cheek teeth possess large dental crowns, resting partly in the bony alveolus. Over a horse's life cheek teeth erupt continuously to compensate for occlusal wear of 3-4 mm per year. Parts of the crown initially resting in the bony alveolus become progressively exposed at the occlusal surface with time. Hitherto, it is unclear whether the typical structure of the equine occlusal surface, composed of a complex arrangement of enamel, dentin and cementum, remains constant or undergoes structural changes with age. Therefore, we tested the hypothesis that the occlusal surface composition does not remain constant by a quantitative analysis of the dental substances at multiple levels along the dental crown of equine cheek teeth.<h4>Methods</h4>Micro-computed tomography scans of 20 upper cheek teeth and 16 lower cheek teeth from 19 domestic horses were morphologically analysed using imaging and measurement software. Area for individual dental substances was measured at different levels from the apex to the occlusal surface. The data was statistically analysed to detect changes in the area of individual substance along the dental crown. The area of peripheral cementum was measured separately for levels inside and outside the bony alveolus.<h4>Results</h4>In both, upper and lower cheek teeth, enamel area decreased in an apical direction, while dentine area increased. Peripheral Cementum increased dramatically in the occlusal/coronal extra-alveolar position.<h4>Conclusion</h4>With increasing age the occlusal surface content of dentine increases while the content of enamel decreases. These changes are considered relevant for the detailed explanation of forage disruption in horses as well as for the recommendation of concepts in equine dentistry.
Project description:This study was performed to 1) quantify dentists' treatment thresholds for occlusal primary caries; 2) determine if the patient's age affects dentists' decisions to surgically treat these carious lesions; and 3) test the hypothesis that patients', dentists', and practices' characteristics are significantly associated with surgical enamel intervention.The study used a cross-sectional design consisting of a questionnaire survey in Japan. This study queried dentists working in outpatient dental practices who were affiliated with the Dental Practice-Based Research Network Japan (JDPBRN), which aims to allow dentists to investigate research questions and share experiences and expertise (n=282). Participants were asked whether they would surgically intervene in a series of cases depicting occlusal caries. Each case included a photograph of an occlusal surface displaying typical characteristics of caries penetration and written descriptions of adult and pediatric patients at high caries risk.In a case of a carious lesion within inner enamel, the proportion of dentists who indicated surgical intervention was significantly higher in adult patients (48%) when compared with pediatric patients (34%; p<0.01). Logistic regression analysis showed that using a dental explorer for the diagnosis of primary occlusal caries, type of practice, practice busyness, and percentage of patients who self-pay were significantly associated with dentists' decisions to intervene surgically into the inner enamel carious lesion.These findings demonstrate that more than one-third of participants chose to intervene surgically into inner enamel carious lesions, and patients' age affects dentists' decisions about when to intervene surgically (clinicaltrials.gov registration number NCT01680848).
Project description:We present a two-dimensional (2D) snapshot multispectral imager that utilizes the optical transmission characteristics of nanohole arrays (NHAs) in a gold film to resolve a mixture of input colors into multiple spectral bands. The multispectral device consists of blocks of NHAs, wherein each NHA has a unique periodicity that results in transmission resonances and minima in the visible and near-infrared regions. The multispectral device was illuminated over a wide spectral range, and the transmission was spectrally unmixed using a least-squares estimation algorithm. A NHA-based multispectral imaging system was built and tested in both reflection and transmission modes. The NHA-based multispectral imager was capable of extracting 2D multispectral images representative of four independent bands within the spectral range of 662 nm to 832 nm for a variety of targets. The multispectral device can potentially be integrated into a variety of imaging sensor systems.
Project description:Dental caries is a major oral disease resulting from a complex interaction between the commensal microbiota, host susceptibility (heredity, immunity, diseases, etc.) and environmental factors (diet, dental hygiene, etc.). To predict the patient's risk of new carious lesions or progression of existing lesions, the Caries Risk Assessment (CRA) takes account of clinical, biological and behavioural factors. Thus, the CRA can predict whether the patient is at high or low risk of developing caries. The practitioner can thus set up a follow-up adapted to the risk of the patient. However, although bacteria are the main etiological factor of carious lesions, the CRA does not consider bacterial quantification or just focus on the level of S. mutans in the saliva. As the majority of cavities are interproximal in adolescence, the aim of this trial is to identify and quantify the interdental microbiota of adolescents aged from 15 to 17 years with low or high carious risk. So, the quantification of new biomarkers associated with carious lesion could be added to the CRA to improve it.
Project description:We demonstrate noninvasive structural and microvascular contrast imaging of different human skin diseases in vivo using an intensity difference analysis of OCT tomograms. The high-speed swept source OCT system operates at 1310 nm with 220 kHz A-scan rate. It provides an extended focus by employing a Bessel beam. The studied lesions were two cases of dermatitis and two cases of basal cell carcinoma. The lesions show characteristic vascular patterns that are significantly different from healthy skin. In case of inflammation, vessels are dilated and perfusion is increased. In case of basal cell carcinoma, the angiogram shows a denser network of unorganized vessels with large vessels close to the skin surface. Those results indicate that assessing vascular changes yields complementary information with important insight into the metabolic demand.
Project description:<h4>Objectives</h4>A practical approach to three-dimensional (3D) intraoral imaging would have many potential applications in clinical dentistry. <i>Stationary</i> intraoral tomosynthesis (sIOT) is an experimental 3D imaging technology that holds promise. The purpose of this study was to explore <i>synthetic</i> radiography as a tool to improve the clinical utility of the images generated by an sIOT scan.<h4>Methods</h4>Extracted tooth specimens containing either caries adjacent to restorations (CAR) or vertical root fractures (VRF) were imaged by sIOT and standard dental radiography devices. Qualitative assessments were used to compare the conspicuity of these pathologies in the standard radiographs and in a set of multi-view <i>synthetic</i> radiographs generated from the information collected by sIOT.<h4>Results</h4>The sIOT-based <i>synthetic</i> 2D radiographs contained less artefact than the image slices in the reconstructed 3D stack, which is the conventional approach to displaying information from a tomosynthesis scan. As a single sIOT scan can be used to generate <i>synthetic</i> radiographs from multiple viewing angles, the interproximal space was less likely to be obscured in the <i>synthetic</i> images compared to the standard radiograph. Additionally, the multi-view <i>synthetic</i> radiographs can potentially improve the display of CAR and VRFs as compared to a single standard radiograph.<h4>Conclusions</h4>This preliminary experience combining <i>synthetic</i> radiography and sIOT in extracted tooth models is encouraging and supports the ongoing study of this promising approach to 3D intraoral imaging with many potential applications.
Project description:This study was conducted to assess caries treatment thresholds among Japanese dentists and to identify characteristics associated with their decision to intervene surgically in proximal caries lesions within the enamel. Participants (n = 189) were shown radiographic images depicting interproximal caries and asked to indicate the lesion depth at which they would surgically intervene in both high- and low-caries-risk scenarios. Differences in treatment thresholds were then assessed via chi-square tests, and associations between the decision to intervene and dentist, practice, and patient characteristics were analyzed via logistic regression. The proportion of dentists who indicated surgical intervention into enamel was significantly higher in the high-caries-risk scenario (73.8%, N = 138) than in the low-caries-risk scenario (46.5%, N = 87) (p < 0.001). In multivariate analyses for a high-caries-risk scenario, gender of dentist, city population, type of practice, conducting caries-risk assessment, and administering diet counseling were significant factors associated with surgical enamel intervention. However, for a low-caries-risk scenario, city population, type of practice, and use of a dental explorer were the factors significantly associated with surgical enamel intervention. These findings demonstrate that restorative treatment thresholds for interproximal primary caries differ by caries risk. Most participants would restore lesions within the enamel for high-caries-risk individuals.
Project description:Existing multispectral imagers mostly use available array sensors to separately measure 2D data slices in a 3D spatial-spectral data cube. Thus they suffer from low photon efficiency, limited spectrum range and high cost. To address these issues, we propose to conduct multispectral imaging using a single bucket detector, to take full advantage of its high sensitivity, wide spectrum range, low cost, small size and light weight. Technically, utilizing the detector's fast response, a scene's 3D spatial-spectral information is multiplexed into a dense 1D measurement sequence and then demultiplexed computationally under the single pixel imaging scheme. A proof-of-concept setup is built to capture multispectral data of 64 pixels?×?64 pixels?×?10 wavelength bands ranging from 450?nm to 650?nm, with the acquisition time being 1?minute. The imaging scheme holds great potentials for various low light and airborne applications, and can be easily manufactured as production-volume portable multispectral imagers.