Background:No studies have been reported on the frequency and aetiology of facial injuries due to MVAs in Queensland. This study aims to investigate the incidence, aetiology, age and sex distribution of facial injuries resulting from MVAs for a period of three years. Method: Cases were identified from the Motor Accident Insurance Commission, Queensland. Information including the type of injury sustained, the time, age and role of the patient in the accident were recorded and analysed. Results: There was an average maxillofacial injury incidence of 4.8/100,000 per year, 53.5 per cent in males and 46.5 per cent in females. A peak incidence was found for both sexes aged 18 to 22 years. In males, 57 per cent of facial injuries occurred in this age group compared to 41 per cent in females. Conclusions: Maxillofacial injuries as a result of MVAs are still relatively high regardless of the legislation for compulsory seatbelt use. Recent advances in seatbelt systems have the potential to reduce the risk of head and face impacts. The airbag is also well established as an effective means of preventing serious head and face injury. However, more research is required to further reduce the incidence of maxillofacial injuries as a result of MVAs.

The measured values of specific traits of occlusion may be subject to significant change due to growth and maturation of the dentofacial structures. Some traits may show improvement while others may show deterioration. Rarely is there an opportunity to examine a sample of occlusions 25 years after the acquisition of the original set of records. This study examines the changes in traits of occlusion in a sample of 46 subjects who were originally examined between 1971-1973 and for whom records were again obtained in 1998. Methods: The 46 patients were a sub-group of a previously selected randomised school-based sample and study models obtained in 1971-1973 were still available. New models for each patient were obtained in 1998. Of the 46 subjects, only eight had received orthodontic treatment. Results: Assessments of the changes in specific traits were made using the methods proposed in the Harry L Draker, California Modification (HLD Cal Mod) index. This simple index was chosen because the main component traits were well defined and, when analysed separately, reflected changes with time. The total index score gave a broad indication of the global changes in the individual's occlusion. The five basic traits of the HLD index include overjet, overbite, openbite, mandibular protrusion and labio-lingual spread. Three additional traits (ectopic eruption, anterior crowding and posterior crossbite) are used in the HLD Cal Mod index. These traits provided a useful reflection of occlusal changes with time. Measurements were made with reference to specifications and the details outlined in the HLD Cal Mod protocol. The results revealed an increase in total index scores over time with a significant increase in lower labio-lingual spread associated with an increased score in anterior crowding. Overjet and overbite, however, displayed a significant decrease with time. Conclusions: These findings are in keeping with previous studies and highlight the importance of time as a significant issue in the assessment of occlusion.

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