Peer Assessment Rating (PAR) index outcomes for orthodontic and orthognathic surgery patients.

The Peer Assessment Rating (PAR) index is commonly used to evaluate occlusal outcomes after orthodontic treatment. We compared the PAR outcomes of 40 consecutively treated orthodontic patients and 40 orthognathic patients to evaluate the standard of care given. A patient-centred questionnaire was used to examine patients' perceptions of the benefits of orthognathic treatment. PAR scores of orthodontic and orthognathic patients improved by a mean of 77% and 74%, respectively, after treatment indicating that excellent to good occlusal results were achieved for both groups. A high quality occlusal outcome is important for all patients as good intercuspation at the end of treatment is thought to improve stability. Most orthognathic patients reported improvements in their dental and facial appearance and thought that the treatment had been beneficial.

Are societal judgments being incorporated into the uncertainty factors used in toxicological risk assessment?

The aim of this paper is to show that the uncertainty factors used in toxic risk assessment to develop exposure standards do contain societal judgments as well as technical judgments. The process generally used today originated in the 1950s, when a deterministic approach to risk was the norm. Technical judgments are required concerning the nature and the quality of the evidence used in the risk assessment. Judgments taken are essentially cautious. This caution may not matter when measured exposure is significantly below the standard and may be accepted when exposure occurs only following an approval process based on "gate keeping." More sophisticated judgments are required when actual exposure may exceed this type of standard or when risk needs to be compared with benefit. These circumstances can occur with patient exposure to human medicines and with occupational exposure to chemicals. Under these circumstances more explicitly considered societal judgments concerning what constitute "broadly acceptable" and "tolerable" risk criteria, and hence what are appropriate uncertainty factors, are required. The outcomes of those societal judgments are likely to vary according to the circumstances surrounding the exposure and have led to smaller uncertainty factors being considered appropriate for occupational exposure, when compared with widespread public exposure.

Assessment of toxicity for major hazards: some concepts and problems.

Approaches to the assessment of the toxic effects which may arise from chemical Major Hazards are examined. The definitions of hazard and risk and the types of toxicity data required for risk analysis are investigated with particular reference to the quality of the data and models available.