Induction of cellular hypersensitivity to oral microorganisms in guinea-pigs

The ability of oral microorganisms (Actinomyces viscosus, Bacteroides melaninogenicus, Veillonella alcalescens and Streptococcus mutans) to elicit cellular hypersensitivity in guinea-pigs was investigated by the macrophage migration inhibition test. All animals sensitized with these microorganisms, emulsified in oil adjuvant, yielded peritoneal cells which were significantly inhibited in migration by the homologous bacterial antigen. These microorganisms showed no cross-reactions and there was little quantitative difference in their ability to elicit cellular hypersensitivity.     

Relationship between bilateral condylar bone change and mandibular morphology: a study using morphometry

This study was undertaken to evaluate the relationship between bilateral condylar bone change (BCBC) and mandibular morphology. Thirty Japanese women with BCBC as diagnosed from computed tomographic scans were compared to 2 control groups: 26 Class I and 25 Class II Japanese women. All cephalograms were traced and scanned, and 14 homologous landmarks were digitized. Coordinates were used for cephalometric analysis, Procrustes analysis, Euclidean distance matrix analysis (EDMA), and thin-plate spline (TPS) analysis. Comparison of the cephalometric data for the BCBC and Class I groups revealed significant shrinkage in the condylar process and ramus height, in addition to a shorter body length. The centroid size showed that BCBC mean geometric forms were smaller than those of Class I and Class II. The landmark morphology of the BCBC group differed from both Class I and Class II, as shown by the residuals (P < .001). EDMA showed expansion of infradentale-pogonion (9.9%) and along the anterior slope height of the condyle (28.6%), while the posterior slope height decreased (21.6%). The vertical ramus height (gonioncondylion) also decreased by 11.8% in comparison to Class I. Compared to Class II, BCBC ramus height was shorter by 8.9%, condylar width decreased 13.7%, and the posterior condylar slope was 22% shorter. TPS analysis showed increased antegonial notching, a vertically expanded symphysis, and a collapsed and more horizontal condyle in the BCBC group. The combination of the above methods was very helpful in assessing mandibular morphology and showed that BCBC might be related not only to changes in the condyle, but may dictate changes in the rest of the mandible as well.     

Delayed formation of a lower second premolar

Delayed odontogenesis of a lower second premolar is presented in a case treated without extraction and focuses on the 7-year follow-up of the delayed tooth bud. The follow-up was initiated when the crown formation was diagnosed and was finished when the tooth erupted completely into the orthodontically provided space, which enabled the orthodontic leveling and alignment of the delayed premolar. The long follow-up indicates that delayed tooth buds may develop completely and normally.     

Cartilage formation by serial passaged cultured chondrocytes in a new scaffold: Hybrid 75:25 poly(L-lactide-ε-caprolactone) sponge

PURPOSE: This study was designed to determine whether multipled chondrocytes immersed in a new scaffold, 75:25 poly(L-lactide-epsilon-caprolactone) sponge coated with type I collagen (75-PLC scaffold), could be used to generate cartilage tissue in vivo and to evaluate the correlation between cartilage generation and the phenotype of the proliferated chondrocytes. MATERIALS AND METHODS: Rat chondrocytes were suspended in 75-PLC scaffold at a density of 1 x 10 7 cells/mL after proliferation in a monolayer for 1 (P1) to 4 passages (P4) and implanted in nude mice for 4 weeks. Cells were characterized by the expression of genes encoding type II collagen, aggrecan, and type I collagen by Northern hybridization, and consequently, the newly formed tissue was evaluated histologically. RESULTS: The expression of aggrecan messenger RNA gradually decreased with the passaged cultures; however, the expression of type I collagen messenger RNA increased with time. The cartilage formations in all specimens were found not only in P1 chondrocytes but also in P2 chondrocytes, although when P3 chondrocytes were grafted, approximately 50% of cartilage formation was still observed up to but not beyond P4. CONCLUSION: It is suggested that cartilage tissue is generated with cultured chondrocytes up to P2 but not beyond P4. Northern blot analysis is useful for the assessment of whether the cells are capable of regeneration.     

Correlation of haloperidol levels between submandibular saliva and brain in the rat

OBJECTIVE: The clinical usefulness of therapeutic drug monitoring (TDM) for haloperidol using blood samples has to be validated. Despite the potential advantage of TDM using saliva, there are few reports comparing drug levels in saliva and blood. Additionally, the relation between haloperidol levels in saliva and brain, the target organ of this drug, has not been reported. We compared haloperidol levels in rat submandibular saliva, plasma and brain. DESIGN: Haloperidol was administered through the femoral vein (0.25 mg/kg). Submandibular saliva was collected 30 min after drug administration. To stimulate secretion, the chorda (parasympathetic) and superior cervical ganglion (sympathetic) were electrically stimulated, and pilocarpine was administered. The concentration of haloperidol in saliva, plasma and brain homogenate was determined. RESULTS: Haloperidol levels in saliva elicited by any stimuli significantly correlated with levels in the brain and plasma. The correlation of haloperidol between saliva and brain was higher than that between plasma and brain. Immunohistochemistry showed that haloperidol was secreted from striated duct cells within the submandibular gland. CONCLUSION: These results suggested that haloperidol was specifically secreted from the striated duct system, and that salivary drug levels reflect the levels in the brain more precisely than plasma.     

Study on the fracture strength of root reconstructed with post and core: alveolar bone resorbed case

This study evaluated the influence of alveolar bone level on the fracture resistance of root restored with post and core. Forty-eight extracted human mandibular premolars were divided into six groups. Cast posts and cores were cemented (MN8 and MP8) or resin cores were built up with fiber posts and composite resin (FN8, FP8, FN4, and FP4). Post length was 8 mm (MN8, MP8, FN8, and FP8) or 4 mm (FN4 and FP4). Specimens were embedded 2 mm (MN8, FN8 and FN4) or 5 mm (MP8, FP8 and FP4) below cement-enamel junction. All specimens were loaded at 45 degrees to the long axis until fracture. With normal bone model, cast post and core (MN8) showed the highest fracture resistance (2262.4 N). However, in the resorbed bone model, there were no significant differences in fracture resistance between cast post and core and fiber post with composite resin.     

Effect of infection with Eikenella corrodens on the progression of ligature-induced periodontitis in rats

The periodontopathic ability of Eikenella corrodens 1073-R (EcR) on ligature-induced periodontal defects in immunosuppressed and non-immunosuppressed rats was studied bacteriologically and histologically. Silk ligatures were placed around the maxillary second molars of rats, and the rats were divided into eight groups. Four groups received cyclophosphamide (CY), an immunosuppressive agent, the day after ligature placement. On days 3 and 4, the oral cavities of the rats in all four groups were inoculated with 8 x 10(8) cells of live EcR. Rats were sacrificed on d 1, 3, 5, 8, 11 and 18. Alveolar bone resorption of ligated rats was enhanced by the implantation of EcR, although the number of total cultivable bacterial cells from ligated sites was not changed by the implantation of EcR. CY suppressed the number of white blood cells, inflammatory cellular infiltrates in gingival tissue, and repair of periodontal tissue, and enhanced bone destruction. The implantation of EcR in the ligature- and CY-treated rats also enhanced osteoclastic bone resorption. Without ligatures, high doses of CY or EcR inoculum did not result in periodontal destruction. These results indicate that it is possible to establish EcR in conventional rat flora with a ligature and that EcR causes osteoclastic bone resorption in this model.     

Local ofloxacin delivery using a controlled-release insert (PT-01) in the human periodontal pocket

PT-01, a controlled-release insert, was developed for topical chemotherapy in periodontal disease. It is a soluble insert that consists of fast-release and sustained-release parts containing ofloxacin (OFLX) as an antibacterial agent. In this study, the release profile of OFLX from PT-01 was investigated in vitro. Twelve adult volunteers were administered OFLX as PT-01 or as an aqueous solution into their periodontal pockets, OFLX concentrations in gingival crevicular fluid (GCF) were evaluated from the viewpoint of pharmacokinetics. The in vitro release profile of OFLX from PT-01 showed a biphasic pattern. The release rate of OFLX was relatively rapid in the early phase and slow thereafter. When OFLX aqueous solution was administered into periodontal pockets, the OFLX level in GCF rapidly decreased to be about 1/100 after 30 minutes. When PT-01 was inserted into the pockets, the OFLX level in GCF immediately reached a peak (about 12 mg/ml), and gradually decreased until the 3rd day, and maintained a constant level above 2 micrograms/ml, the effective minimum antibacterial concentration for periodontopathic microorganisms, from the 3rd to 7th day after insertion. No side-effects were observed in the volunteers who received the PT-01 insert. The above results suggest that PT-01 is a suitable pharmaceutical preparation for periodontal chemotherapy.