Prediction of mechanical properties of the cancellous bone of the mandibular condyle

The mechanical properties of cancellous bone depend on the bone structure. The present study examined the extent to which the apparent stiffness of the cancellous bone of the human mandibular condyle can be predicted from its structure. Two models were compared. The first, a structure model, used structural parameters such as bone volume fraction and anisotropy to estimate the apparent stiffness. The second was a finite element model (FEM) of the cancellous bone. The bone structure was characterized by micro-computed tomography. The calculated stiffnesses of 24 bone samples were compared with measured stiffnesses. Both models could predict 89% of the variation in the measured stiffnesses. From the stiffness approximated by FEM in combination with the measured stiffness, the stiffness of the bone tissue was estimated to be 11.1 +/- 3.2 GPa. It was concluded that both models could predict the stiffness of cancellous bone with adequate accuracy.     

Isolation and characterization of aminopeptidase from Capnocytophaga granulosa ATCC 51502

There is evidence that enzymes from the genus Capnocytophaga play a role in dental calculus formation. Although most of the species in the genus produce aminopeptidases, there is a paucity of data on the purification and characterization of the enzyme, except in the case of Capnocytophaga gingivalis. The aim of this study was to purify aminopeptidase from culture supernatant of Capnocytophaga granulosa ATCC 51502, a new species of the genus. Purification was performed using ammonium sulfate fractionation and two chromatographic steps. The aminopeptidase was purified 158,433-fold with a yield of 12.0%. The enzyme appeared to be a trimer with a molecular mass of 270 kDa. The optimal pH of the aminopeptidase was 6.5 and its activity was completely inhibited by incubation at 50 degrees C for 10 min. The enzyme showed maximum specificity for basic amino acids (Arg and Lys) and also hydrolyzed noncharged amino acids (Met, Leu and Ala). Ca(2+), Zn(2+) and Fe(3+) activated the enzyme, while EDTA, Ag(+), Hg(+) and Cu(2+) inhibited it. These results suggest that aminopeptidase of C. granulosa is different from that of C. gingivalis but similar to aminopeptidase B.     

Extensive bleeding during surgical treatment for gingival overgrowth in a patient on haemodialysis--a case report and review of the literature

Before performing renal transplantation, a most important concern is to control any infection, including oral infections before transplantation. The bleeding diathesis of patients with uraemia is a significant clinical concern, especially when surgery is required. A 44-year-old female patient on haemodialysis was referred for evaluation of gingival overgrowth. The patient was planning a renal transplantation two months later. As the lesions were not considered successfully treatable before transplantation, a gingivectomy and teeth extraction was performed. In pre-operative examinations, an abnormal bleeding time was not detected and other coagulation tests were normal. Under general anaesthesia, 19 teeth were extracted and overgrown gingiva was removed. During the operation, extensive blood loss of 1650ml occurred and four units of concentrated red blood cells were transfused. This study suggests that patients with renal failure undergoing dental surgery require careful pre-surgical evaluation including assessment of their coagulation ability.     

Oral health status of 5 years and 12 years school going children in Chennai city--an epidemiological study

India, a developing country, faces many challenges in rendering oral health needs. The majority of Indian population resides in rural areas of which more than 40% constitute children. The purpose of this study was to assess the oral health status of 5 years and 12 years school going children in Chennai city. The study population consisted of 1200 school children of both the sexes (600 private and 600 corporation school children) in 30 schools, which had been selected randomly. The survey is based on WHO, 1999 Oral Health Assessment, which has been modified by including gingival assessment, enamel opacities/ hypoplasia for 5 years. Evaluation of the oral health status of these children revealed, dental caries is the most prevalent disease affecting permanent teeth, more than primary teeth and more in corporation than in private schools, thereby, correlating with the socioeconomic status. It may be concluded that the greatest need of dental health education is at an early age including proper instruction of oral hygiene practices and school based preventive programs, which would help in improving preventive dental behaviour and attitude which is beneficial for life time.     

Das Heerfordt-Syndrom — eine seltene Erstmanifestation der Sarkoidose

Sarcoidosis is a chronic, multisystem disorder of unknown cause characterized by noncaseating epithelioid granulomas. Infectious agents and genetic components have been discussed. Heerfordt’s syndrome with uveitis, enlargement of the parotid glands and optional paralysis of the Nn. facialis is a form of sarcoidosis. The diagnosis is confirmed by histology. Further analyses are fiberoptic bronchoscopy with bronchoalveolar lavage or the gallium-67 scan in combination with blood findings. The therapy of choice is glucocorticoids. We present a case report of Heerfordt’s syndrome and a review of the literature covering different aspects of sarcoidosis.     

External cervical resorption of a primary canine

Summary. The authors describe the case of a 3-year-old boy who presented with a mobile right maxillary primary canine. Clinical examination revealed this tooth to have an abnormally large crown, which appeared to have sustained a crown–root fracture. Periodontal probing depths of 5 mm were detected around the tooth. Radiographically, there was a marked constriction at the cementoenamel junction with associated alveolar rarefaction. Both upper primary canines were subsequently removed under general anaesthetic and the right canine was subject to histopathological investigation. A diagnosis of external cervical resorption was made. A review of the literature confirmed this to be a very unusual case presentation.     

Missing facial parts computed by a morphable model and transferred directly to a polyamide laser-sintered prosthesis: an innovation study

Mirroring of missing facial parts and rapid prototyping of templates have become widely used in the manufacture of prostheses. However, mirroring is not applicable for central facial defects, and the manufacture of a template still requires labour-intensive transformation into the final facial prosthesis. We have explored innovative techniques to meet these remaining challenges. We used a morphable model of a face for the reconstruction of missing facial parts that did not have mirror images, and skin-coloured polyamide laser sintering for direct manufacture of the prosthesis. From the knowledge gleaned from a data set of 200 coloured, three-dimensional scans, we generated a missing nose that was statistically compatible with the remaining parts of the patient's face. The planned prosthesis was manufactured directly from biocompatible skin-coloured polyamide powder by selective laser sintering, and the prosthesis planning system produced a normal-looking reconstruction. The polyamide will need adjustable colouring, and we must be able to combine it with a self-curing resin to fulfil the requirements of realistic permanent use.     

Foreign body ingestion in dental practice

Most foreign bodies pass through the gastrointestinal tract uneventfully. The majority of the reported literature describes the management of ingested blunt objects. However, ingestion of sharp objects can still occur with a higher rate of perforation corresponding to treatment dilemmas. We report a case of inadvertently ingested sharp foreign body by a special child, which was retrieved by endoscopic guided forceps. Urgent endoscopic assessment and retrieval of recently ingested sharp dental foreign body is indicated and routine use of preventive measures such as rubber dam, gauze throat screens or floss ligatures is suggested.     

CAD/CAM-produced surgical guides: Optimizing the treatment workflow

The increased availability of devices for 3D radiological diagnosis allows the more frequent use of CAD/CAM-produced surgical guides for implant placement. The conventional workflow requires a complex logistic chain which is time-consuming and costly. In a pilot study, the workflow of directly milled surgical guides was evaluated. These surgical guides were designed based on the fusion of an optical impression and the radiological data. The clinical use showed that the surgical guides could be accurately placed on the residual dentition without tipping movements. The conventional surgical guides were used as a control for the manual check of the deviation of the implant axis. The direct transfer of the digital planning data allows the fabrication of surgical guides in an external center without the need of physical transport, which reduces the logistic effort and expense of the central fabrication of surgical guides.