The mechanical behaviour of human mandibles studied by electronic speckle pattern interferometry.
An understanding of the mechanical behaviour of the human mandible during mastication may be useful in several specific medical fields that examine the maxillofacial area. In this research, the Electronic Speckle Pattern Interferometry Optical Technique was applied to study a dry mandible under external stress. Two images of the mandible, i.e. an image of the relaxed mandible and another of the mandible under stress, were processed using this technique and provided information concerning the most stressed areas of the bone. The advantage of interferometric analysis is that it can be carried out in real time on a mandible to which progressively greater stress has been applied. This research may be of value in maxillofacial surgery, for example, in the diagnosis and treatment of fractured mandibles, and in oral surgery and orthodontics, where it can provide information concerning stress dispersion when an osteointegrated implant or orthodontic appliance is placed in the mouth. One of the most important conclusions to be drawn from the experiments of tension, compression, and in- and out-of-plane deformations is that the capability of the mandible to bend is superior to its capability to stretch. Several quantitative results support this conclusion. (+info)
Infectious health care workers: should patients be told?
The risk of transmission of HIV or hepatitis B from infectious health care workers to patients is low. However, inadvertent exposure causes great concern amongst patients of an infected health care worker. The patients of a Scottish dentist diagnosed hepatitis B e antigen positive were informed by letter of their exposure. A sample of patients was sent a postal questionnaire. Most (56%) respondents reported feeling anxious on receiving the letter but almost all (93%) thought patients should always be informed following treatment by an infectious health care worker, although the risk was very small. We discuss clinical and ethical factors relating to informing patients following exposure to an infectious health care worker. We suggest that a balance should be struck between patients' wishes to know of risks to which they have been exposed, however small, and the professional view that when risks are negligible, patients need not be informed. (+info)
In situ self hardening bioactive composite for bone and dental surgery.
A new biomaterial is presented which consists of a cellulose derivative--silanised hydroxyethylcellulose (HEC-SIL) and biphasic calcium phosphate (BCP). Rheological properties of the polymer itself and its mixture with BCP are pH-dependent. At pH 10-12 HEC-SIL is liquid and undergoes quick gellation at pH < 9. Similarly, the paste of HEC-SIL and BCP is fluid and injectable at higher pH and solidifies in biological solutions. The rate of this solidification can be easily controlled by the degree of substitution of hydroxyethylcellulose with silicoalkoxy groups. (+info)
Work-related noise hazards in the dental surgery.
The paper discusses sources and characteristics of noise in the dental surgery as well as the mechanism of noise-induced hearing loss. Analysis of the influence of office noise on the hearing of dental doctors has been carried out and the significance of nonoccupational factors noted. Suggestions have been offered on how to reduce noise levels in the surgery. (+info)
Assessing competence in surgical dentistry.
The growing demand for assessment in all aspects of surgical competencies will inevitably embrace the whole of dental surgery. The aim of this paper is to review the literature and discuss some of the issues that will have to be addressed as objective assessment of the surgical dentists' skills is introduced. The paper reviews what is meant by competence and how we assess it, with particular emphasis on practical and technical skills. Specific methodologies for assessing competence are described including, as illustrations, two means of assessing the removal of lower wisdom teeth. The evaluation of competence in the workplace is discussed together with the difficulty in assessing important attributes such as attitude. It concludes that the assessment of competence is a valuable tool in its own right and a means of demonstrating to the public the continuing commitment of the profession to the highest possible standards. However assessment will be very time consuming and to be worth while we must ensure that it is done in a way that produces clear and unambiguous benefits and solves real problems. (+info)
Effects of a computerized treatment simulation on patient expectations for orthognathic surgery.
One hundred forty-six patients, ranging in age from 15 to 50 and presenting with a moderate to severe dentofacial disharmony requiring orthodontics and orthognathic surgery, were randomly assigned to 2 preparation strategy groups: standard presurgical consultation with or without a computerized treatment simulation presentation. The demographic profiles of the 2 groups were similar. Viewing a treatment simulation did not have a significant effect on the anticipation of social/interpersonal or general health problems in the first month after surgery. These 2 areas of concern were significantly related to psychological well-being. Psychologically distressed patients, whether or not they saw a simulation, expected significantly more problems in social/interpersonal relations and in general health during the first month after surgery. A treatment simulation presentation did affect patients' overall expectations of problems in the first month after surgery and their concerns about symptom recovery. However, the impact of the presentation was related to the patient's psychological well-being. In the standard presurgical consultation group, the average anticipated level of overall problems and discomfort during recovery was significantly higher for patients who reported elevated psychological distress than for those who did not. In the treatment simulation group, the average level of concern was similar for those patients who reported distress and those who did not. Preparation strategy was not significantly related to the long-term expectation of improvement after treatment. Long-term expectation of treatment improvement was related to psychological distress and gender. Men tended to report similar expectations regardless of psychological well-being, while women who were distressed anticipated significantly more improvement overall, in self-image, and in general health after treatment than women who were not distressed. (+info)
Clinical and computerized assessment of mandibular asymmetry.
The aim of this study was to investigate assessment of mandibular asymmetry by clinicians and to evaluate a new computerized system. Eight experienced clinicians (four maxillofacial surgeons and four orthodontists) assessed 12 standardized facial photographs of patients selected to provide a range, from normality to marked mandibular asymmetry. Photographs were taken under standardized conditions; analysis of photographs repeated after one month showed close agreement. The computerized system used four different methods for quantifying asymmetry based on right/left differences in perimeter, area, compactness, and centre of area ratios. Good agreement (kappa = 0.77) was achieved by the clinicians in assessing the likelihood of treatment need; however, when assessing an 'acceptable' level of asymmetry, agreement was moderate (kappa = 0.46). Differences in perimeter ratios did not compare well with clinical assessment, but those for both area and compactness showed 100 per cent sensitivity and specificity to clinical assessment at ratio differences of 0.05 and 0.03 (deviation from 1), respectively. A centre of area difference ratio greater than 1 showed 75 per cent sensitivity and 85 per cent specificity to clinical assessment. These parameters could prove useful in quantifying change in asymmetries brought about by growth, treatment, or any subsequent relapse. (+info)
Use of simulation technology in dental education.
Simulation is becoming very beneficial in the area of health care education. Dentistry has used various types of simulation in preclinical education for some time. This article discusses the impact of the current simulation laboratories on dental education and reviews advanced technology simulation that has recently become available or is in the developmental stage. The abilities of advanced technology simulation, its advantages and disadvantages, and its potential to affect dental education are addressed. (+info)