Effect of antibodies on chemiluminescence and on killing of Streptococcus sobrinus by polymorphonuclear leukocytes

The effect of a polyclonal antiserum and OMVU10, a monoclonal antibody reactive with Antigen B of Streptococcus sobrinus , on the interaction of polymorphonuclear leukocytes with S. sobrinus was studied, using chemiluminescence and bacterial killing assays. Increased stimulation of neutrophils as measured in the chemiluminescence assays was established when S. sobrinus was preincubated with polyclonal antiserum or when polyclonal antiserum was added to the reaction mixture. Higher counts were measured in comparison to preimmune serum. After 90 min, 52% of S. sobrinus preincubated with polyclonal antiserum was killed. Killing was also increased when polyclonal antiserum was added to the reaction mixture in comparison to the controls. No killing was found when bacteria were preincubated with OMVU10 or when OMVU10 was added to the reaction mixture in comparison to Clone 24, a control antibody.     

Xerostomia: evaluation of a symptom with increasing significance

Xerostomia is the subjective sensation of oral dryness. Although it is most commonly associated with salivary gland dysfunction, it may also occur with normal gland activity. Xerostomia may be an early symptom of several morbid systemic conditions with important implications for the medical and dental management of patients. Oral dryness also has negative effects on an individual's emotional well-being and quality of life. The complaint of xerostomia necessitates a complete evaluation of a patient's general health, salivary gland function, and oral motor and sensory abilities. The salivary gland assessment includes symptom review, analysis of glandular secretions, scintiscanning, and minor labial gland biopsy. No single component is sufficient to adequately diagnose the presence, extent, or cause of salivary dysfunction. Treatment of a dry mouth, to date, is mainly palliative in nature, with the intent of preserving oral structures and functions. Better therapies are essential in the management of xerostomia, whatever the cause. The importance of xerostomia as a symptom is increasingly recognized in medicine and dentistry. The dentist is commonly the first health professional to hear this complaint and may be critical in directing a full and appropriate evaluation.     

Three-dimensional finite-element model of the human temporomandibular joint disc during prolonged clenching

In the temporomandibular joint (TMJ), overloading induced by prolonged clenching appears to be important in the cascade of events leading to disc displacement. In this study, the effect of disc displacement on joint stresses during prolonged clenching was studied. For this purpose, finite-element models of the TMJ, with and without disc displacement, were used. Muscle forces were used as a loading condition for stress analysis during a time-period of 10 min. The TMJ disc and connective tissue were characterized as a linear viscoelastic material. In the asymptomatic model, large stresses were found in the central and lateral part of the disc through clenching. In the retrodiscal tissue, stress relaxation occurred during the first 2 min of clenching. In the symptomatic model, large stresses were observed in the posterior part of the disc and in the retrodiscal tissue, and the stress level was kept constant through clenching. This indicates that during prolonged clenching the disc functions well in the asymptomatic joint, meanwhile the retrodiscal tissue in the symptomatic joint is subject to excessive stress. As this structure is less suitable for bearing large stresses, tissue damage may occur. In addition, storage of excessive strain energy might lead to breakage of the tissue.     

Rectal ketamine and midazolam for premedication in pediatric dentistry

Rectally administered midazolam (0.30 mg/kg) and ketamine (5 mg/kg) were compared for preanesthetic medication in children undergoing dental extractions. Sixty patients between the ages 2 and 9 years were randomly allocated to three groups in this double-blind study. In one group of patients who received ketamine rectally, intravenous midazolam (0.05 mg/kg) also was administered immediately after induction of anesthesia. The results from this trial show that 30 minutes after rectal administration of the two drugs, good anxiolysis, sedation, and cooperation were obtained in most patients. Although midazolam appeared to be marginally more efficacious than ketamine in the majority of assessments made and seemed to have less adverse effects, no statistically significant differences could be shown. Ketamine showed a slight decrease and midazolam a slight increase in average blood pressures after premedication. These blood pressure differences were, however, considered to be of little clinical importance.     

Dynamic shear properties of the temporomandibular joint disc

Shear stress might be an important factor associated with fatigue failure and damage of the temporomandibular joint disc. Little information, however, is available on the dynamic behavior of the disc in shear. Since the disc is an anisotropic and viscoelastic structure, in the present study the dependency of the dynamic shear behavior on the direction and frequency of loading was examined. Ten porcine discs were used for dynamic shear tests. Shear stress was applied in both anteroposterior (A-P test) and mediolateral (M-L test) directions. The dynamic moduli increased as the loading frequency increased. The dynamic elasticity was significantly larger in the A-P test than in the M-L test, although the dynamic viscosity was similar in both tests. The present results suggest that non-linearities, compression/shear coupling, and intrinsic viscoelasticity affect the shear material behavior of the disc, which might have important implications for the transmission of load in the temporomandibular joint.     

The CICERO system for CAD/CAM fabrication of full-ceramic crowns

The CICERO method of crown fabrication consists of optically digitizing a gypsum die, designing the crown layer buildup, and subsequently pressing, sintering, and milling consecutive layers of a shaded high-strength alumina-based core material, a layer of dentin porcelain, and a final layer of incisal porcelain. Final finishing is performed in the dental laboratory. The CICERO method allows efficient production of all-ceramic restorations without compromising esthetics or function. This article reviews the process involved in the fabrication of a CICERO crown.     

Prognosis of caries increment with past caries experience variables

This study aimed to select past caries experience variables as caries predictors and to compare their prognostic accuracy with the variables used in a method of caries prognosis developed in a Swiss child population. The data used for the analyses originated from an 8-year longitudinal study starting in 1980 on caries of 7.5-year-old Dutch children. Stepwise logistic regression analyses provided predictor variables. The newly introduced variables D23fi, D(123)i and D23pifi were interchangeable and the most powerful caries predictors. For the sake of uniformity and ease of application, D23fi (number of fissures of the permanent first molar with non-cavitated or cavitated caries lesions) was chosen as the first variable in the logistic regression equations. The gain in accuracy of the second and third predictor variables (number of sound primary molars and the number of buccal and lingual smooth surfaces of the permanent first molar with non-cavitated or cavitated caries) in the regression equations was limited. The D1 condition of surfaces could be omitted from the prediction models. The present forced three-predictor-regression equations for 7.5-, 9.5- and 11.5-year-old children were evaluated to assess their prognostic performance by using the area under the ROC curve as a measure of prognostic quality. For the present regression equations, the area under the ROC curve was 81-87%, which was higher compared to the Swiss regression equations for caries prognosis.     

Adhesion of Porphyromonas gingivalis strains to cultured epithelial cells from patients with a history of chronic adult periodontitis or from patients less susceptible to periodontitis

BACKGROUND: The present study aimed to explain the interindividual variation in periodontitis susceptibility by differences in the initial adhesion rate of Porphyromonas gingivalis to the pocket epithelium of these individuals, and/or by inter-P. gingivalis strain differences in association capacity (adhesion and internalization). METHODS: Adhesion assays were performed on epithelial monolayers (cultured in vitro from pocket epithelium belonging to patients who were less or more susceptible to chronic adult periodontitis) using 11 genetically different clinical strains of P. gingivalis. RESULTS: Both the disease category (less susceptible versus susceptible) and the interstrain variation were found to have a significant effect (both P <0.05) on the initial bacterial association. The chronic adult periodontitis group showed significantly more association of P. gingivalis when compared to less susceptible patients (4.2 x 10(6) versus 3.5 x 10(6)). Also, the interstrain variation was significant, with strains Pg 4 and 5 representing the least and best associating bacteria (1.8 x 10(6) colony forming units for Pg 4, 9 x 10(6) for Pg 5). CONCLUSIONS: These results indicate that periodontitis susceptibility is influenced by both the interindividual differences in pocket epithelium (allowing more adhesion of P. gingivalis) or by the strain type by which the patient is infected (intra-species differences in adhesion capacity).     

CT diagnosis of synovial chondromatosis of the temporomandibular joint

Synovial chondromatosis of the temporomandibular joint (TMJ) is a very rare condition. It is characterised by the presence of loose bodies in the joint space. Clinical signs, histopathological findings and radiography play an important role in the diagnostic process. Conventional X-rays have shown to be of limited value, for they fail to depict the intra-articular loose bodies in a significant amount of cases. Axial as well as coronal computer tomography (CT) is extremely useful in detecting loose bodies in the temporomandibular joint (TMJ). In this report we present and discuss a further case, and the use of CT in the diagnosis of TMJ-synovial chondromatosis is illustrated.