Biomedical subjects
Publications and source records attributed to F Mackay.
Lateral skull cephalograms from 50 patients who subsequently had surgical correction of their Class III malocclusion were analysed using a complete linkage cluster analysis based on skull shape. Five subgroups were identified and are described. All subjects had a degree of mandibular prognathism while only 14 per cent had maxillary retrognathism. An increased lower face height was found in 58 per cent.
Fine-mesh based brackets were bonded to plastic cylinders using four different adhesives. Adhesive thickness was controlled using a bonding jig. The bond was then tested to failure using a shear force. Each adhesive had its own minimum thickness, probably related to its viscosity. Increasing the thickness of the adhesiveness to 0.26 mm, using a stainless steel spacer had minimal effect on their mean shear bond strength.
The results of two audit projects carried out in a District Orthodontic Unit are described. Although prospective data collection was the goal, it was found that this method yielded little information as the data collection forms were poorly filled in. The main problem was a lack of definition of terms and inadequate discussion between clinical and clerical staff. A retrospective audit using five clearly defined fields was more successful. It is very important that there is provision to verify the data collected. The time commitment for clinical staff should not be underestimated.
This study compares the results of cephalometric analyses using manual and interactive computer graphics methods. Results are statistically in favour of the interactive computer system. This study provides a basis for ongoing research into alternative methods of cephalometric analyses, such as digitization and automatic landmark identification using sophisticated computer vision systems.
During the 10-year period 1978-87 there were 48 outbreaks of food poisoning in Scottish hospitals affecting a total of 2287 persons of whom 12 died. This compared with 50 outbreaks during the previous 5 years (1973-77) when over 1500 persons and 7 deaths were recorded. Although the incidence of outbreaks has decreased the average number of persons affected in outbreaks has increased. A marked reduction was seen in the incidence of outbreaks due to Clostridium perfringens, in contrast to foodborne salmonellosis which remains a problem. Thirty-four hospitals, of which 10 reported two or more outbreaks, were involved. The type of hospitals most frequently affected were general (14), psychiatric (13), geriatric (9) and hospitals for the mentally subnormal (7). Meat, including poultry meat, was incriminated in over 90% of outbreaks where a food vehicle was identified. In modern or re-equipped kitchens cooking in advance with subsequent reheating is being progressively discontinued as more food is being cooked on the day of consumption, a practice which may readily explain the decreasing incidence of outbreaks due to Cl. perfringens. Bacterial cross-contamination from poultry-meat and other raw foods, compounded by inadequate temperature control, however, continues to be a problem in some hospitals. It is too early as yet to determine whether the removal of Crown immunity will have any effect on the future incidence of hospital 'food poisoning'.