Annals of the Royal Australasian College of Dental Surgeons最新文献

Three-dimensional Le Fort I DO can be used to selectively widen, lengthen, and vertically reposition the maxilla, without bone grafts and with a good adaptation of the surrounding soft tissues. Therefore DO is a complementary tool for conventional orthodontics and orthognathic surgical techniques that address maxillary deficiency. It is the technique of choice for patients who require significant maxillary repositioning and have significant soft tissue limitations, such as scarring secondary to previous surgical procedures. The procedure can be performed in children prior to reaching skeletal maturity and also in adult patients. Finally, three-dimensional maxillary reconstruction by distraction of the Le Fort I segment offers an improved aesthetic outcome and less risk of deterioration of speech in comparison with traditional orthognathic techniques.

Maxillary deformities of cleft lip and palate (CLP) can be treated by either conventional osteotomies (CO) or distraction osteogenesis (DO). Which one is better for CLP patients suffering from a moderate extent of maxillary hypoplasia? The aim of the study was to evaluate the treatment outcomes of CO and compared with DO in correction of moderate maxillary hypoplasia. The results showed that CLP patients receiving DO were more anxious and depressed during the first three months but became happier in the long-term. The nasalance of DO and CO was found to be similar. However, on the skeletal stability, DO was shown to be significantly more stable when compared with CO in the horizontal plane within the first six months and in vertical plane during the first three months and between 1-2 year.

Background: Danshen is a traditional Chinese medicine used for treatment of cardiac diseases through improving blood circulation. The authors' laboratory compared the amount of new bone formed in collagen matrix with Danshen extract with that produced by bone graft and collagen matrix alone.

Methods: Eighteen bone defects, 5 mm x 10 mm were created in the parietal bone of nine New Zealand White rabbits. In the experimental group, six defects were grafted with a collagen matrix with Danshen extract. In the control groups, six defects were grafted with collagen matrix alone (active control) and six were left empty (passive control). The animals were killed on day 14 and the defects were dissected and prepared for histological assessment. Serial sections were cut across each defect. Quantitative analysis of new bone formation was made on 100 sections (50 sections for each group) using image analysis.

Results: A total of five times more new bone was present in defects grafted with Danshen extract in a collagen matrix than those grafted with collagen matrix alone. Very little new bone was formed in the passive control group.

Conclusions: Danshen extract in collagen matrix has the effect of increasing new bone formation locally and can be used for bone grafting especially in cases with compromised vascular responses.

The C-shaped canal system often is a challenge to optimal cleaning and shaping. This present study was aimed to determine the incidence of fused root patterns, which indicates the presence of a C-shaped canal system, in mandibular second molars of ethnic Chinese in Hong Kong. One thousand clinical and radiographic records of patients in a dental teaching hospital were randomly selected and screened. From the panoramic radiographs, 399 patients with a total of 769 mandibular second molars were suitable for analysis. Of these selected patients, 370 (92%) presented with both 37 and 47, of which 108 (29%) pairs showed the same fused root pattern. Of all 769 second molars examined, 203 (26%) presented with a radiographic Type I morphology, and 68 (9%) and 54 (7%) with Type II and III morphology, respectively. It was concluded that approximately 42% of fused-root mandibular second molars of Hong Kong Chinese patients might be associated with a C-shaped root canal system.

Over the last decade the development of adhesives has moved from the classic concept of three-step bonding towards the introduction of more user-friendly, simplified systems. Current adhesive systems can be grouped into three categories: etch and rinse adhesives, self-etch materials and glass ionomers. Published data indicate that the three-step etch and rinse systems form the gold standard in durability, with the two-step self-etch materials approaching that standard, and the glass ionomers, although clinically reliable, are limited by their physical properties. However, a major shortcoming of bonded restorations is their unreliable durability in vivo. One of the most important factors influencing bond durability is hydrolysis, which affects all adhesive systems. Two important aspects of this process involve water uptake in the adhesive resin and thinning or disappearance of collagen fibrils from within the hybrid zone. Techniques to improve the stability of the adhesive bond and prolong the clinical life of adhesive restorations are discussed.

External apical root resorption (EARR) is frequently associated with orthodontic treatment, however, the amount of root resorption is rarely of clinical significance. Severe EARR does, however, constitute a clinically significant problem. In contrast to the vast majority of the literature pertaining to EARR, the focus of this research project was restricted to only severe cases of EARR. The purpose of this study was to test whether frequently cited treatment-related variables played a significant role in the development of severe EARR. The difference between minor and severe EARR seems unlikely to be associated with the treatment that is received, but is instead inextricably linked to the genetic makeup of the patient.

Smoking is a risk factor for periodontitis but there are conflicting reports about the relationship between the severity of periodontitis and smoking behaviour, in part because self-reported smoking status may be inaccurate. Cotinine, a major metabolite of nicotine with a longer half-life (17 h versus 30 min), may be a more useful biochemical marker of smoking status. Smoking behaviour, plasma cotinine levels, and measures of periodontitis severity in 135 adults with moderate-advanced periodontitis were studied. Smokers had comparable periodontitis at a younger age than non-smokers. Smoking, as measured by cigarettes smoked per day and plasma cotinine levels, was significantly related to the severity of periodontitis.

A number of fallacies and even fads and rarely facts have arisen in regard to catering to the medically-complex/pharmacologically-challenged dental patient. Dentists face an ever-increasing problem in addressing the needs of their medically-complex patients, given the increase in their numbers, with the advances in medicine, and the aging of the population, notwithstanding, their increased dental needs. Dentists usually approach such patients with a mixture of fear and trepidation--as undergraduates they had little direct experience in treating such patients, and as graduates, they often end up referring to hospital institutions such complex patients. This fear and trepidation can only be but reinforced by the increasing litigiousness of our society. This presentation will attempt to demystify some of these so-called medical complexities, and address the fallacies and fads that have arisen in the provision of safe dental care to these patients, and offer the facts (nothing but the facts), as to the appropriate management of the medically-complex dental patient. In addition, how an approach based on the concepts of evidence-based medicine/dentistry can actually be of help and the resources available for the dentist in the management of this ever expanding group of patients will be demonstrated.