Composite autogenous bone and demineralized bone matrices used to repair defects in the parietal bone of rabbits

We compared the amount of new bone produced by endochondral and intramembranous autogenous bone grafts in the presence of demineralized bone matrices (DBMs) prepared from intramembranous bone (DBM(IM)) or endochondral bone (DBM(EC)). Thirty-five bone defects were created in the parietal bone of 20 New Zealand White rabbits. In the experimental groups, 5 defects were grafted with endochondral bone, 5 with endochondral bone mixed with DBM(IM)) (EC-DBM(IM)), 5 with intramembranous bone mixed with DBM(IM)(IM-DBM(IM)) and 6 with endochondral bone mixed with DBM(EC)(EC-DBM(EC)). In the control groups, 10 defects were left alone (passive control) and 4 were grafted with rabbit skin collagen (active control). They were all killed on day 14 and the defects were prepared for histological study. Serial sections were cut across the whole defect. Quantitative analyses were made on 202 sections of the experimental groups by image analysis. A total of 414%, 708%, and 85% more new bone was formed in defects grafted with composite EC-DBM(IM), IM-DBM(IM)and EC-DBM(EC), respectively, than those grafted with endochondral bone alone (P<0.001). No bone was formed in either passive or active controls. In conclusion, demineralized bone matrices, particularly those derived from intramembranous bone, have extremely high osteoinductive properties and greatly improve the integration of autogenous bone grafts in the skull.     

Oral carriage of Candida species and coliforms in patients with burning mouth syndrome

The oral carriage of Candida species and coliforms in a healthy adult population and a group of patients with burning mouth syndrome (BMS) was investigated. The intra-oral prevalence of Candida species and coliforms was higher in the BMS group compared with the controls. The most frequent yeast isolated from the BMS group was Candida albicans while Enterobacter and Klebsiella species were the most prevalent coliforms. The possible reasons and the significance of the above findings are discussed.     

The role of dentistry in patients undergoing bone marrow transplantation

It is imperative that a comprehensive dental examination should be performed in all patients who are to undergo a bone marrow transplantation. Such assessments should be carried out prior to and after the transplantation procedure. This paper addresses the implications of marrow transplantation and the impact on dental treatment. The side-effects of transplantation chemotherapy, radiation treatment and graft versus host disease and their impact on the oral cavity are also discussed in this paper.     

Dental caries in adult and elderly Chinese

This paper reports on a study of dental caries conducted among 1744 urban and rural Chinese (from 20 to 80 years old), who were selected by means of a systematic stratified sampling procedure. The prevalence of one or more decayed or filled teeth ranged from 48 to 90% in urban residents, and from 51 to 97% in rural residents, depending on age. The mean number of decayed or filled teeth ranged from 1.2 (+/- 1.9) among 20-29-year-olds, to 6.2 (+/- 5.5) among 70+-year-olds, and was highest among rural residents. Among 20-29-year-olds, the main components of the DFT were enamel lesions and fillings. Among 30-49-year-olds, the DFT consisted mainly of enamel lesions and filled teeth, as well as teeth with lesions involving the pulpal tissues. In subjects over the age of 50 years, lesions involving pulpal tissues were the predominant type, followed by root-surface lesions. In subjects below the age of 50 years, most of the caries experience derived from coronal surfaces, particularly occlusal surfaces. Root-surface caries was predominantly a feature of persons aged 50 years and above. Despite a large number of surfaces being at risk of root-surface caries, less than 10% of the surfaces were so affected. Although cross-sectional in nature, these data indicate that when the oral hygiene standards are poor, caries lesions continue to develop and progress throughout life. With age, dental caries becomes a substantial oral health problem in this population of adult and elderly Chinese, despite the availability of some dental services.     

The development of an index of orthodontic treatment priority

The aim of this study was to develop a valid and reproducible index of orthodontic treatment priority. After reviewing the available literature, it was felt that this could be best achieved by using two separate components to record firstly the dental health and functional indications for treatment, and secondly the aesthetic impairment caused by the malocclusion. A modification of the index used by the Swedish Dental Health Board was used to record the need for orthodontic treatment on dental health and functional grounds. This index was modified by defining five grades, with precise dividing lines between each grade. An illustrated 10-point scale was used to assess independently the aesthetic treatment need of the patients. This scale was constructed using dental photographs of 12-year-olds collected during a large multi-disciplinary survey. Six non-dental judges rated these photographs on a visual analogue scale, and at equal intervals along the judged range, representative photographs were chosen. To test the index in use, two sample populations were defined; a group of patients referred for treatment, and a random sample of 11-12-year-old schoolchildren. Both samples were examined using the index and satisfactory levels of intra- and inter-examiner agreement were obtained.     

Endurance and recovery from a sustained isometric contraction in human jaw-elevating muscles

Ten males sustained maximal voluntary contractions (MVC) of the jaw elevators. Unilateral bite force and electromyographic (EMG) activity were recorded from the right masseter and temporalis. The experiment comprised three endurance trials, and each trial consisted of two sustained 100% MVC clenching tasks. Between the two tasks, the subjects took a randomly assigned rest of either 30, 120 or 300 s. Immediately after each task, they performed an additional brief 100% MVC to check for contractile failure. EMGs were taken from the beginning and end of each sustained 100% MVC and used to determine and compare the EMG centre frequency. The difference in endurance times between the first and second clenchings was greatest for the 30-s rest and progressively decreased as the rest period increased. The beginning EMG centre frequency was significantly greater than the end for each clenching. These findings strongly support the proposal that even though the jaw elevators are resistant to a contractile element failure, a contraction-induced pain is produced, which limits a sustained jaw-closing effort. Recovery from this effort pain is related to the post-contraction blood flow.     

The post-operative maxillary cyst. Experience with 23 cases

23 cases, diagnosed as post-operative maxillary cyst, from outside Japan are described. Clinical, radiographic and histopathological features are not dissimilar to those cases reported from Japan, and various parameters have been found to be helpful in diagnosis. This lesion is more common outside Japan than previously suggested, and this is probably largely due to faulty diagnosis.