Current perspectives: calcium phosphate nanocoatings and nanocomposite coatings in dentistry.

The purpose of coatings on implants is to achieve some or all of the improvements in biocompatibility, bioactivity, and increased protection from the release of harmful or unnecessary metal ions. During the last decade, there has been substantially increased interest in nanomaterials in biomedical science and dentistry. Nanocomposites can be described as a combination of two or more nanomaterials. By this approach, it is possible to manipulate mechanical properties, such as strength and modulus of the composites, to become closer to those of natural bone. This is feasible with the help of secondary substitution phases. Currently, the most common composite materials used for clinical applications are those selected from a handful of available and well-characterized biocompatible ceramics and natural and synthetic polymers. This approach is currently being explored in the development of a new generation of nanocomposite coatings with a wider range of oral and dental applications to promote osseointegration. The aim of this review is to give a brief introduction into the new advances in calcium phosphate nanocoatings and their composites, with a range of materials such as bioglass, carbon nanotubes, silica, ceramic oxide, and other nanoparticles being investigated or used in dentistry.

Three-dimensional modelling and finite element analysis of the human mandible during clenching.

BACKGROUND: Until recently, very few papers have been published concerning the development, analysis and experimental verification of three-dimensional, finite element modelling of the human adult edentulous mandible. The purpose of this study was to improve the method of modelling by using computer-aided engineering (CAE) and computer-aided design (CAD) methods and to utilize the model in analyzing maxillofacial problems. METHODS: The model geometry was derived from position measurements taken from 28 diamond blade cut cross-sections of an average size human adult edentulous mandible and generated using a special sequencing method. Data on anatomical, structural, functional aspects and material properties were obtained from measurements and published data. The materials were idealized as transversely isotropic. The complete model consisted of 258 solid elements and 1635 nodes. RESULTS: The model was solved for displacements and stresses during clenching. In general, the observed displacement and stresses (tensile and compressive) were highest around the condylar region. Compressive stress was also observed around the premolar and molar bite points. CONCLUSION: This investigation has shown that the use of computer-aided modelling in conjunction with the finite element analysis could be effectively utilized in biomechanical analysis of the mandible. It could help to investigate many functional problems and could reduce the time of extensive experimentations.

Tongue cancer: do patients younger than 40 do worse?

BACKGROUND: Debate continues as to whether being young confers a worse prognosis for patients with squamous cell carcinoma of the tongue. Recent papers have provided conflicting views in this debate. In this study we aimed to investigate if young age at the time of diagnosis of squamous cell carcinoma of the tongue confers a worse prognosis. METHODS: Eligible patients were identified through the computer database of the Department of Radiation Oncology, Westmead Hospital, Sydney. All eligible patients were treated with radical intent. Using age 40 as a cut off multivariate and survival analysis was undertaken to compare age groups. RESULTS: Median age at diagnosis was 60 years (range, 19-86 years) in 84 males (65 per cent) and 45 females (35 per cent). Median follow-up time was 43 months (range, 2.3-203 months). Fifteen patients (12 per cent) were aged <40 years. On univariate analysis stage and age were significant determinants of disease-specific survival. There was no difference in overall survival between the young (<40 years) and middle-aged groups (40-60 years). However, the young and the middle aged were both more likely to survive than the older age group (>60 years). On multivariate analysis age remained a significant factor for determining disease-specific survival, with the older age group 2.9 times more likely to die than the younger groups. CONCLUSION: Young age (<40 years) did not portend to worse survival in comparison to older tongue cancer patients.

Spontaneous coping strategies to manage acute pain and anxiety during electrodiagnostic studies.

Electrodiagnostic studies produce both anxiety and pain, which can prevent adequate examination and limit the usefulness of test results. This study examined the spontaneous coping strategies used to manage the pain and anxiety experienced during electrodiagnostic testing. Fifty patients (26 women and 24 men) evaluated in our electrodiagnostic laboratory were administered visual analogue scale (VAS) pain and anxiety measures and the Spielberger State-Trait Anxiety Inventory (STAI) before the procedure. Immediately after the procedure, subjects reported pain, anxiety, and coping strategies used during electrodiagnostic testing using the VAS, the STAI, and a situation-specific version of the Coping Strategies Questionnaire (CSQ-S). The CSQ-S appears to be a valid and reliable measure of spontaneous coping strategies. Multiple-regression analyses revealed that frequent use of catastrophizing, diverting attention, and coping self-statement strategies was significantly and positively correlated with pain, whereas reinterpreting pain was significantly and negatively associated with pain. Judgments of control over pain were also significantly and negatively associated with anxiety experienced during electrodiagnostic studies. Physicians' ratings of pain and anxiety were highly correlated with patients' self-reports. This study suggests that ineffective coping strategies may enhance the pain and anxiety experienced during electromyography. Alternatively, teaching subjects active self-control skills and increasing patients' self-efficacy beliefs may help manage this situation-specific acute anxiety and, possibly, the associated pain.