Orbital infection arising from a primary tooth: a case report

Odontogenic infections may spread to the orbit by one or more of several paths. Such extension is potentially dangerous and may lead to loss of vision. A case of infection from a primary tooth, which extended to the retrobulbar area is presented in this report. Treatment included surgical drainage of the resulting subperiosteal orbital abscess through a Caldwell-Luc approach as well as aggressive antibiotic therapy. The importance of early suspicion of this entity and its potential sequelae are discussed.     

High-dose-rate mold brachytherapy of early gingival carcinoma: a clinical report

Two elderly edentulous patients with the diagnosis of early stage cancer of the upper gingiva were treated by customized dental mold brachytherapy. Locoregional tumor control was achieved in both patients. One patient is alive without any evidence of disease 36 months after treatment, the other patient died of distant metastasis shortly after brachytherapy. Brachytherapy, being easy to apply with short treatment time and good acute tolerance, is a good choice and effective modality for the management of early stage gingival cancer, particularly in elderly patients.     

Accuracy of implant impression splinted techniques: effect of splinting material

Three implant impression techniques, using 3 different splinting materials, were assessed for accuracy in a laboratory model that simulated clinical practice. For group A, an autopolymerizing acrylic resin was used to splint transfer copings. In group B, a dual-cure acrylic resin was used, and for group C, plaster, which was also the impression material, was used. A metal implant master cast with an implant master framework was made to accurately fit to the cast. This cast was the standard for all impressions. For each group, 15 impressions were made. Polyether impression material was used for groups A and B. The accuracy of the stone casts with the implant analogues was measured against the master framework, using strain gauges. A multiple analysis of variance with repeated measures was performed to test for significant differences among the 3 groups. Additional analyses of variance were carried out to locate the source of difference. The statistical analyses revealed that a significant difference existed between groups A and B and between groups B and C but not between groups A and C. Impression techniques using autopolymerizing acrylic resin or impression plaster as a splinting material were significantly more accurate than dual-cure acrylic resin. Plaster is the material of choice in completely edentulous patients, since it is much easier to manipulate, less time consuming, and less expensive.     

Managed Care in Dental Markets: Is the Experience of Medicine Relevant?

OBJECTIVE: This paper reports on factors that predict the market penetration and growth into the market of both medical and dental managed care, and the relationship between the two. METHODS: Using data from the National Association of Dental Plans, the Interstudy Competitive Edge HMO Census, and the Area Resource File from 1987-95, we created an analytic data base covering the dental HMO market, the medical HMO market, dentist and physician supply, and regional market characteristics. Simple correlation analysis and multivariate linear regression using ordinary least-squares techniques were used to predict medical HMO penetration and dental HMO penetration in each state during 1994 and 1995. RESULTS: The results show that although the penetration of dental HMOs has been modest when compared to medicine, its growth is predictable by the same factors, and closely follows the pattern found in medical markets. CONCLUSIONS: Despite the observed relationship between medical and dental HMO penetration rates, there are potential barriers to managed care in the case of dentistry that may explain the slower growth to date, and that may ultimately decide the extent of managed care penetration into the dental market.     

Inhibition of Actinomyces viscosus – Porphyromonas gingivalis coadhesion by trypsin and other proteins

Protease activity is associated with the coadhesion of Actinomyces viscosus and Porphyromonas gingivalis. To try to distinguish whether the recognition/adhesion or degradative functions of proteases are more crucial for coadhesion, we determined the effect of trypsin and other purchased proteases and proteins on coadhesion when they were incorporated in the coadhesion assay buffer or when A. viscosus cells were pretreated with trypsin. Coadhesion was measured by the decrease in turbidity caused by the absorption of A. viscosus cells from aqueous suspension by P. gingivalis-coated hexadecane droplets. Pretreatment of A. viscosus with trypsin had no obvious effect on the kinetics of coadhesion. Likewise, trypsinization of A. viscosus failed to aid or enhance coaggregation by chemically induced, trypsin activity-deficient mutants of B. gingivalis. In contrast, incorporating trypsin in the buffer during the coadhesion assay yielded a concentration-dependent inhibition of coadhesion greater than the inhibition found with the same concentration of other proteases. Coadhesion was also impaired to a greater extent by similar wt/vol concentrations of nonproteolytic proteins (bovine serum albumin (BSA), defatted BSA, gelatin, and casein), by antisera against whole P. gingivalis cells and fimbriae, by preimmune serum, and by the amino acid arginine but not lysine. These findings suggest that the role of proteases in coadhesion is not solely to enzymatically "prime" A. viscosus for more avid coadhesion and that their role as potential protein or peptide seeking adhesins should be considered.     

Epithelial expression of major histocompatibility complex (MHC) antigens in normal rat salivary and lacrimal glands.

The presence and distribution of MHC class I and class II antigens within these glands of Wistar and Lewis rats was studied using monoclonal antibodies and an indirect immunoperoxidase technique. In rats of both strains and sexes, MHC class 1 antigens were expressed by ductal epithelium in addition to vascular endothelium and other connective tissue elements. Except for a small proportion of secretory cells within lacrimal glands, acini were uniformly negative for class I antigen. MHC class II immune response-associated (Ia) antigens were expressed by stromal dendritic cells in all glands. Glandular expression of Ia was limited to submandibular glands of the two strains. In Lewis rats, staining was detected in some striated and collecting ducts, whereas positive glandular reactivity in Wistar rats was predominantly within the granular-cell tubules. Quantitative histomorphometric studies of Wistar submandibular glands, taken from 2.5-60-week-old male and female animals, demonstrated a close relationship between the extent of glandular Ia reactivity and postnatal granular-cell tubule development. These results indicate that whilst constitutive expression of Ia is a feature of rat submandibular epithelium, the glandular components involved are strain dependent.     

Nifedipine-induced gingival hyperplasia.

Gingival hyperplasia is an adverse reaction of nifedipine therapy. Oral manifestations of this condition include enlarged and painful gingiva accompanied by spontaneous bleeding. Nifedipine-induced gingival hyperplasia may be reversible once a proper drug substitution is made. Two cases of gingival hyperplasia resulting from nifedipine are described and the drug's possible mode of action is discussed.     

Responses of calcitonin gene-related peptide-immunopositive nerve fibres in the periodontal ligament of rat molars to experimental tooth movement.

Nerve fibres showing CGRP-immunoreactivity were exclusively distributed around blood vessels in the periodontal ligament of normal teeth. The CGRP-positive nerves as well as the vessels were more dense during tooth movement and reached a maximum density and intensity of immunoreaction after 3 days. After that, the immunoreactive nerves gradually disappeared, and returned to the control level by the 7th day. Some of the CGRP-nerves were adjacent to bone resorptive lacunae at 3 days when active remodelling of alveolar bone was taking place. These findings suggest that the distribution of CGRP-positive nerves is dynamically changed around the blood vessels in the periodontal ligament during tooth movement, and that CGRP might affect the regulation of blood flow in the ligament. CGRP is possibly involved in the tissue remodelling, directly or indirectly, in addition to its function as a neurotransmitter.