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Intracranial and Body Stereotactic Radiotherapy
Published in W. P. M. Mayles, A. E. Nahum, J.-C. Rosenwald, Handbook of Radiotherapy Physics, 2021
Jim Warrington, Vivian Cosgrove
For fractionated SRT treatments, there is a need for simple but accurately ‘relocatable' fixation of the patient. Such requirements led to a range of developments (Gill et al. 1991; Kooy et al. 1994a; Sweeney et al. 2001; AAPM 2005), from traditional thermoplastic masks to frames that locate onto the patient's upper dentition, as with the Gill-Thomas repeat localiser (Figure 40.6). The use of upper dentition moulds has since been incorporated into other commercial head fixation systems such as in Elekta relocatable frames. The accuracy of dental impression-based frames is obviously compromised by poor dentition. Commercial thermoplastic masks have become sufficiently refined to provide the next level of accurate relocation and are usually the system of choice when used in conjunction with integrated imaging systems in the treatment room.
Current Status and Role of Dental Polymeric Restorative Materials
Published in Mary Anne S. Melo, Designing Bioactive Polymeric Materials for Restorative Dentistry, 2020
Haohao Wang, Suping Wang, Xuedong Zhou, Jiyao Li, Libang He, Lei Cheng
Dental caries is known as the destruction of dental hard tissues by acidic by-products from bacterial metabolism of dietary carbohydrates (Selwitz et al. 2007). Despite the great efforts in caries prevention, it is still one significant public health problem globally, and dental restorations are the most commonly used approach to restore decayed teeth (Selwitz et al. 2007). Apart from that, restorations also play an essential role in clinical treatment, including tooth wear, dental trauma, and esthetic purposes. Although all kinds of restorative materials emerge in an endless stream, there are generally two common categories of restorative dental materials: direct and indirect materials, both have their specific indications for clinical use (AFFAIRS ACOS 2003). The former category includes most commonly used filling materials like amalgam, resin composites, glass ionomer cement (GIC), etc., which are placed directly into a tooth cavity and shaped intraorally. The indirect restorations are fabricated outside of the mouth via dental impressions of a prepared tooth, such as crowns, inlays and onlays, bridgework, and veneers (Loomans and Özcan 2016).
Calcium Phosphate and Bioactive Glasses
Published in Vincenzo Guarino, Marco Antonio Alvarez-Pérez, Current Advances in Oral and Craniofacial Tissue Engineering, 2020
Osmar A. Chanes-Cuevas, José L. Barrera-Bernai, Iñigo Gaitán-S., David Masuoka
The hemihydrated form of calcium sulfate is more commonly known by orthopedic surgeons as plaster of Paris (Fig. 4.1), a material used for splinting and plastering (Hak 2007). It has long been used to immobilize fracture areas, and has also been widely used as dental impression material (Tang et al. 2010).
Bardet-Biedl syndrome-7 (BBS7) shows treatment potential and a cone-rod dystrophy phenotype that recapitulates the non-human primate model
Published in Ophthalmic Genetics, 2021
Tomas S. Aleman, Erin C. O’Neil, Keli O’Connor, Yu You Jiang, Isabella A. Aleman, Jean Bennett, Jessica I. W. Morgan, Brian W. Toussaint
A custom adaptive optics scanning light ophthalmoscope (AOSLO) was also used in this study (41,42). Patients were aligned to the AOSLO using a dental impression. Wavefront sensing was done using an 848 nm superluminescent diode with a full-width at half-maximum bandwidth (FWHM) of 26 nm (Superlum, Ireland) and aberration correction was provided by a 97 actuator deformable mirror (Alpao SAS, France). Confocal and split-detection images were acquired at 17.85 frames per second over a 1° by 1° field of view using a superluminescent diode centered at 795 nm with FWHM of 15.3 nm (Superlum, Ireland) and a photomultiplier tube (PMT, Hamamatsu Corporation, Japan). The patient was instructed to fixate (using the imaged eye) at a target while the AOSLO image sequences were acquired along the temporal meridian. A custom strip-registration algorithm was used for intra-frame strip-based registration and dewarping of the AOSLO images (41,43,44). Reference frames for registration were chosen automatically from the image sequences and 50 frames were registered and averaged (45,46). Averaged images were then automatically montaged using a previously described algorithm(47). Regions of interest (ROI) were at the fovea and along the temporal meridian. Cones, rods, and RPE cells were identified within the ROIs in a semi-automated fashion, using a previously described algorithm, and densities were extracted from the cell locations (48,49).
Artefact of fixed orthodontic auxiliary appliance in craniofacial CT image
Published in Orthodontic Waves, 2021
Mahmud Mohammed, Norma Ab. Rahman, Ahmad Hadif Zaidin Samsudin
At present, CT systems include specific algorithms for reducing the metal artefact, most of them relying on iterative reconstruction, projection interpolation or filtering algorithms to minimize the intensity of the artefacts [15,16]. Sometimes, this metal artefact reduction technique does not help if the number of artefacts is extremely intense. Moreover, there is additionally a chance of loss of data from the diagnostic image because of using such kind of metal artefact reduction algorithm. Silicone shields made by dental impression material might be another effective way to reduce the metal artefact in CT images. Moreover, a chance of loss of data around the area covered by the silicon shields. This modern technique is more appropriate in reducing artefact from dental restoration and orthodontic bracket. If this method is implemented in possible combination with other CT algorithms for radically reducing the metal artefact, more actual CT images can be achieved, and it will be enormously helpful in future to deal the CT images with the metal artefact. Presently, Cone Beam Computed Tomography (CBCT) has replaced conventional CT imaging in the dentofacial region in most of the clinical situations in the dentistry. So, before reducing the artefacts, dose reduction should be considered.
Development and questionnaire-based evaluation of virtual dental clinic: a serious game for training dental students
Published in Medical Education Online, 2021
Ju-Hui Wu, Je-Kang Du, Chen-Yi Lee
Previous studies related to simulation in dental education mainly focused on the simulated training on psychomotor skills [10]. Serious game for improving the transition of declarative knowledge to procedural knowledge is a new attempt. Two studies [11,12] used randomised control trials to make comparisons between serious games (test group) and traditional learning style (control group) in dental education. Amer [11] reported on using a serious game for teaching dentine bonding and basic knowledge for composite resin filling in operative dentistry. Hannig et al. [12] assessed the effectiveness of Skills-O-Mat, a serious game for training in mixing alginate for dental impression, which is a mandatory skill for dental care. Overall, two key studies [11,12] in our knowledge, suggest that serious games are potentially effective learning tools for dental education, and the students were satisfied with the game-based learning approach. Both studies [11,12] were performed on first-year or second-year dental students to acquire basic science and skills. Games Research Applied to Public Health with Innovative Collaboration-II (GRAPHIC-II) [13] is a serious game for dental public health where students can practice critical thinking and decision-making skills regarding health promotion in a safe environment.