A novel approach to bite force measurements in a porcine model in vivo.

A novel device for a bite force measurement system in a porcine model is described. A single polyethylene layer was vacuum-formed into a splint, and a force sensor was fitted on to the splint occlusal surface and seated with a silicone layer. This design enabled the measurement of bite forces on selected teeth in a large animal model with either natural dentition or single implant crowns and could be used in assessing information on biomechanical adaptation of the bone-implant interface to masticatory loads. Preliminary recordings of force values obtained during mastication in the premolar region (200-560 N) and various limiting factors of the technical design are discussed.

Surgical wafers: a comparative study.

A comparative study of occlusal wafers for orthognathic surgery made for 185 orthognathic surgery patients with the mean age of 24.4+/-4.3 years is presented. This study is intended to highlight any wafer-associated surgical problems, which determine wafer design. Various types of occlusal wafers were used during the period of this review, but in most of the cases a simple quick-cure acrylic wafer was found to be most satisfactory. However, some difficult patients with cleft palates or neuromuscular disorders may require wafers of a novel design and material.

Clinical and histological features of a group of patients with sporadic non-A, non-B hepatitis.

Twelve serologically proven cases of non-A, non-B (NANB) hepatitis have been described. The clinical course was mild in 11 patients. One patient, however, presented in portal systemic encephalopathy and required steroid treatment. Nine of the 12 patients continued to exhibit raised transaminase (AST) activities six or more months after the onset of the acute hepatitis. In these immunoglobulin concentrations were normal and autoantibodies were not present in significant titre. Four patients had evidence of previous hepatitis B infection, suggesting that the route of transmission of NANB might be similar to that of hepatitis B virus. A further four patients gave a history which suggests a possible parenteral mode of transmission. Liver biopsies were carried out both in the acute (8 cases) and chronic (6 cases) phases of the disease. Histological findings in liver biopsies covered the whole spectrum of acute and chronic hepatitis and 1 patient had cirrhosis. One notable feature in these biopsies was the presence of fatty changes.

Fatal Stevens-Johnson syndrome associated with Fansidar and chloroquine.

A fatal case of Stevens-Johnson syndrome associated with Fansidar and chloroquine is reported in a 5-year-old boy.

The role of the occlusal wafer in orthognathic surgery; a comparison of thick and thin intermediate osteotomy wafers.

The aim of this study was to compare two types of osteotomy wafers, derived from model surgery on a semi-adjustable anatomical articulator. The thick wafer was fabricated before autorotation of the mandibular cast and the thin after the autorotation. Twenty-five patients, 19 female and 6 male, who had osteotomies with a maxillary impaction as part of a bimaxillary correction were included in this study. Thick and thin wafers were fabricated and the surgeons were requested to compare both wafers, intra-operatively. Valid results were received for 19 cases, in 14 (74%) the surgeons concluded that both wafers located the maxilla in the same position. In 5 cases (26%) there was up to 2 mm difference in the maxillary position. These were cases when the impaction was > 6 mm, however, chi 2 and Fisher's exact test showed that the difference in impaction between the two groups was not significant (p = 0.06).

The reproducibility of the head position for a laser scan using a novel morphometric analysis for orthognathic surgery.

The aim of this study was to evaluate the reproducibility of the head position for a three-dimensional soft tissue laser scan (lasergraph) using thin-plate splines, for orthognathic surgery planning and follow-up. 60 laser scans of five subjects (12 scans per subject) were obtained at specified intervals. The head was positioned in the lateral view using a spirit level, an engineering device for setting horizontal surfaces, to adjust the Frankfort horizontal plane parallel to the ground. The projection of a narrow beam of longitudinal laser light was used to adjust the axial plane for the frontal view. These scanned images (lasergraphs) were digitised and the co-ordinates of the landmarks recorded. The digitised laser scans were compared using thin-plate splines analysis. The mean difference between the scans due to variations in head position was 0.0135 +/- 0.0109 g x cm2/ sec2 in the lateral view and 0.0090 +/- 0.0054 g x cm2/sec2 in the frontal view. This represents an overall distortion error of less than 2% when following up the surgical change of a typical bimaxillary osteotomy case with 6 mm maxillary advancement and 3 mm mandibular set-back. It is concluded that facial laser scans (lasergraphs) with the Frankfort horizontal plane set using a head rest and spirit level, and the axial plane set using projection of a vertical laser light on the facial midline, are highly reproducible.

A comparative study of two arbitrary face-bow transfer systems for orthognathic surgery planning.

The relative reproducibility of two widely used arbitrary face-bow transfer systems, the Denar Slidematic and the Dentatus type AEB, was assessed for use in orthognathic surgery planning. A novel method was also developed to determine any variation in three-dimensional spatial position and orientation of the maxillary cast. This envelope of movement enabled realistic comparisons to be made for each face-bow system, operator, and skeletal type. The overall face-bow/articulator procedure showed poor reproducibility. However, the Denar Slidematic face-bow was better (P < 0.001) than the Dentatus type AEB standard face-bow, and the errors were higher in the anteroposterior and lateral directions than the vertical direction. There was no significant difference between operators for each system.

Providing support for emergency service staff.

This paper provides a comprehensive review of the literature focusing on post-traumatic stress disorder related to the experience of involvement in major incidents. The structure, role and function of the staff support team set up by the South Tees Occupational Health Psychology Service is described.

Debriefing victims of violence.

Public sector unions have been warning for some time about the effects of violent incidents on their members. OH clinical psychologist, Martin Bamber (right), believes that psychological debriefing can help victims of workplace violence and prevent long term problems.

Orthognathic model surgery by using of a passive Robot Arm.

PURPOSE: The possibility of using a passive Robot Arm (3D method) in model surgery and comparing with manual technique model surgery. PATIENTS AND METHODS: Seventeen patients undergoing orthognathic surgery gave consent for this study. Model surgery was performed by using a manual technique and using the Robot Arm. The model surgery that was performed by using the manual technique named group A and the one performed by the Robot Arm named group B. Patients' maxillary casts were measured before and after model surgery, and results were compared with those for the original treatment plan in the horizontal (X-axis), vertical (Y-axis), and transverse (Z-axis) planes. RESULTS: Statistical analysis using Mann-Whitney U test for X- and Y-axis and independent sample t test for Z-axis have shown significant differences between both groups in X-axis (P = .026) and Y-axis (P = .021) but not in Z-axis (P = .762). CONCLUSIONS: Model surgery performed with a Robot Arm is more accurate in all dimensions X, Y, and Z than the manual model surgery.

Reasons for leaving among psychiatric nurses: a two-year prospective study.

Recruiting and retaining nursing staff has been increasingly identified by nurse managers and the media as a problem of 'crisis' proportions, but until recently there has been very little systematic research into what factors influence the nurse to leave. The present study addressed this issue and asks: 'Why do nurses leave?' and 'What happens to them once they do leave?' This study was a follow-up to an earlier one by Bamber and aimed to generate new information which would either support or reject the findings of the earlier study.

An investigation of occupational stress among nurse tutors.

The quality of education which students of nursing receive relates very much to the qualities of the teacher, their knowledge, skills, motivation etc. This study examines stress factors affecting nurse teachers. The Occupational Stress Indicator (1) was used to pinpoint the sources of stress and its effects upon nurse tutors working for a district health authority within the NHS. Individual qualities and current coping strategies being used were also identified. The findings are listed in the results section of this article, which concludes by looking at further coping strategies that could be adopted to assist stress management among nurse tutors. Improving the job satisfaction of nurse teachers, by reducing stress levels has important implications for nursing practice because of the links between effective education and the provision of a sound knowledge base for nurses involved in patient care.

The optical surface scan as an alternative to the cephalograph for soft tissue analysis for orthognathic surgery.

The aim of this study was to compare cephalographs and optical surface scanner images (lasergraphs) by measuring the lipincisor relationship, the nasolabial angle, nasal tip projection, the nasofacial angle, the nasomental angle, and the labiomental angle in pre- and postoperative orthognathic surgery patients. The results showed that the methods were comparable, but the optical surface scan (lasergraph) could be used to greater advantage for pre- and postoperative assessment of soft tissue changes with orthognathic surgery, because of its clarity and 3-dimensional potential.

Toxic shock: clinical presentation and management. I.

A case of toxic shock syndrome in an 18 year old girl is described, evincing most of the features typical of this disease.

A validation of two orthognathic model surgery techniques.

In order to create an evidence-based orthognathic surgery planning protocol, an investigation of two popular model surgery techniques, the Lockwood keyspacer and the Eastman anatomically-orientated system was carried. This determined (a) the accuracy of positioning of the maxillary cast according to the prescribed treatment plan and (b) the relocation of the maxilla after a simulated Le Fort I down fracture osteotomy using the intermediate wafer as a guide. Fifteen patients-five Class II division 1, five Class II division 2, and five Class III-were included in the study. All the measurements were taken with Erickson's vertically mounted electronic caliper and variations from the treatment plan were analysed. The mean model surgery positioning errors +/- SD (mm) were: (i) vertical plane-Lockwood -0*8 +/- 1*6 and Eastman 0*00 +/- 1*0 (P = 0*0001); (ii) anteroposterior plane-Lockwood 1*2 +/- 1*8 and Eastman -0*1 +/- 1*4 (P = 0*05); and (iii) transverse plane-Lockwood 0*9 +/- 0*9 and Eastman 1*0 +/- 0*9 (P = 0*34). After the simulated osteotomy, the mean errors +/- SD were: (i) vertical plane-Lockwood -0*5 +/- 1*5 and Eastman 0*3 +/- 1*1 (P = 0*001); (ii) in anteroposterior plane-Lockwood 0*8 +/- 2*0 and Eastman 0*7 +/- 1*0 (P = 0*89); and (iii) transverse plane-Lockwood 0*8 +/- 0*6 and Eastman 0*7 +/- 0*5 (P = 0*83). The Eastman technique was relatively better especially in the vertical plane. The variations from the treatment plan were on the whole anatomically small, but in some cases could be clinically significant.