Glycogen synthetic and degradative activities by Actinomyces viscosus and Actinomyces naeslundii of root surface caries and noncaries sites

The relative glycogen synthetic and degradative activities of Actinomyces viscosus and Actinomyces naeslundii, freshly isolated from root surface caries and noncaries sites, were compared. The glycogen synthetic activity was measured by incubating glucose-(or sucrose-)grown resting cells with 100 mM glucose (or sucrose) and U-[14C]-glucose (or U-[14C]-sucrose) on a pH-stat maintained at 5.0, 6.0, and 7.0 for 1 h under anaerobic conditions. For the glycogen degradation assays, after the 1-hour incubation period, the cells were reincubated under similar conditions, but in the absence of external carbon sources. Carbohydrate utilization and total acid formation were also monitored. Both the glucose- and sucrose-grown cells of A. viscosus and A. naeslundii strains originating from root surface caries lesions synthesized approximately twice as much glycogen as the strains of noncaries origin. Although there were significant differences in the rates of glycogen synthesis, the rates of glycogen degradation were essentially the same for the Actinomyces strains from both caries and noncaries sites. However, the time required for glycogen degradation by the strains from caries sites was much longer. This study suggests that the abilities of A. viscosus and A. naeslundii originating from root surface caries lesions to synthesize large amounts of glycogen and to degrade this stored polymer slowly under conditions of starvation, particularly in an acidic environment, may be one of the factors contributing to the cariogenic potential of these organisms in root surface caries.     

CSF-1, RANKL and OPG regulate osteoclastogenesis during murine tooth eruption

During tooth eruption, osteoclast-mediated bone resorption predominates in alveolar bone along the occlusal surface rather than in bone basal to the tooth. CSF-1, RANKL and OPG, regulatory molecules essential for osteoclastogenesis, are expressed during eruption. However, it is unclear if these cytokines exhibit an expression pattern that correlates with sites of osteoclastogenesis in vivo. To address this issue, mouse mandibles, isolated from 1 to 14 days postnatal, were analysed for osteoclast activity using tartrate-resistant acid phosphatase (TRAP) staining as well as colony-stimulating factor-1 (CSF-1), receptor activator of nuclear factor-kappa B ligand (RANKL) and osteoprotegerin (OPG) mRNA expression using in situ hybridisation. Results showed that CSF-1, RANKL and OPG are expressed in a distinct temporal and spatial manner. In the occlusal region, osteoclast activity was maximal at day 5 and correlated with a relative high expression of CSF-1 and RANKL compared to OPG. In basal bone at this time point, osteoclast activity decreased despite persistent CSF-1 expression and was associated with increased expression of OPG compared to RANKL. By day 8, osteoclastogenesis declined and correlated with upregulation of OPG at the occlusal and basal regions, with this effect continuing throughout eruption. These findings suggest that the spatiotemporal pattern and relative abundance of CSF-1, RANKL and OPG during eruption are key determinants of site-specific osteoclast activity in bone surrounding the tooth. Targeting these cytokines to specific regions in alveolar bone may provide a mechanism for regulating osteoclastogenesis in dental disorders associated with altered tooth eruption.     

Concepts for the treatment of adolescent patients with missing permanent teeth

INTRODUCTION: Missing permanent teeth is observed with syndromes or is frequently hereditarily propagated in families. The treatment of these patients is a multi-task of specialists of oral surgery, orthodontics and prosthodontics. DISCUSSION: Despite functional and aesthetic considerations, the main problem of all treatment is that it had to be performed in a growing child. This article discusses the conventional and implant-driven concepts to treat patients from childhood to adolescence with selective or multiple missing permanent teeth.     

Immunhistochemische Untersuchung des Kollagen-Typ-I-Gehalts der Gingiva bei Dysostosis cleidocranialis

Background

Patients with cleidocranial dysplasia (CCD) present a thickend and fibrotic gingiva.

Purpose

To the best of our knowledge it was analysed for the first time, whether this is correlated with an increased rate of collagen I in oral mucosa.

Patients and methods

27 soft tissue biopsies of six CCD-patients and 17 tissue samples of 12 healthy persons were labled with a monoclonal antibody against collagen I and the bound antibodies were detected with alkaline phosphatase-anti-alkaline phophatase-kit. The histological slices were analysed by a digital image recognition software under a fully automated microscope and the rate of collagen I was converted into amounts of grey tones.

Results

The amount of grey tones reached from 11.909 to 15.319 in the CCD-group, and from 2752 to 12.556 in the control group. The U-Test of Mann, Whitney and Wilcoxon for two independent samples generated a rank sum of 91,50 for CCD-patients, and of 79,50 for the control group. The Z-value was 3,246, the p-value 0,005. “Fisher`s exact test” identified a p-value of 0,0003.

Conclusions

The rate of collagen I in the oral mucosa seems to be increased significantly in CCD. This could explain the typical thick and fibrotic consistency of the gingiva and could be one reason for the delayed or missing dentition.     

In vitro assessment of motility and proliferation of human osteogenic cells on different isolated extracellular matrix components compared with enamel matrix derivative by continuous single-cell observation

OBJECTIVES: The composition of the extracellular matrix (ECM) plays a substantial role in bone remodelling, fracture healing and osseointegration of dental implants by regulating proliferation, migration and finally differentiation of osteogenic cell populations. Emdogain, a composition of an enamel matrix derivative (EMD), has been introduced as a potential candidate to promote tissue regeneration. We investigated whether EMD could serve as a potential promoter of cell proliferation and motility as a dynamic cell response and compared the results with the ubiquitous single ECM components type I collagen and laminin. MATERIAL AND METHODS: In the investigation presented, we used a continuous observation method for the analysis of migratory and proliferative patterns of individual cells. We analyzed the response of four osteoblastic cell lines to specific extracellular ligands (type I collagen, laminin and EMD) over a period of 24 h compared with untreated glass surface and bovine serum albumin (BSA) as control groups. RESULTS: Type I collagen and laminin promoted cell motility significantly compared with the control groups and, in part, compared with EMD as well. The analysis of all 451 investigated cells revealed the following mean values for cell motiliy: untreated glass (n=99): 5.46+/-2.74 microm/h, BSA (n=89): 6.35+/-2.43 microm/h, type I collagen (n=108): 8.77+/-3.42 microm/h, laminin (n=74): 9.89+/-5.10 microm/h and EMD (n=81): 7.92+/-3.35 microm/h. Proliferation rates on the different surfaces were heterogenous for all investigated cell lines and varied from 0% to 50% within 24 h without a correlation to cell motility. CONCLUSION: In our study, EMD promotes cell motility better than the control groups. The two investigated single ECM components type I collagen and laminin promoted cell motility superior to EMD. This supports the hypothesis that EMD promotes a less mobile but more differentiated osteogenic phenotype.     

Undifferentiated pleomorphic sarcoma of the orbital region

Undifferentiated pleomorphic sarcoma (formerly known as malignant fibrous histiocytoma) has been established as an entity in the WHO-classification of soft tissue tumors since 2002. Before this the term "malignant fibrous histiocytoma" has been a collective term for soft tissue malignancies that had no distinct components and included most soft tissue sarcomas (40%). With the new classification they account for only about 5%, and tumors arising in the head and neck contribute only about 1-3% of all undifferentiated pleomorphic sarcomas. We report a rare case in which the orbital region was involved.     

Oral health impact in patients wearing removable prostheses: relations to somatization, pain sensitivity, and body consciousness

PURPOSE: Previous studies investigating associations between patient personality traits and complaints related to wearing dental prostheses have been inconclusive. From the perspective of cognitive behavioral theory, the current study investigated whether pain sensitivity, body consciousness, and somatization affected the oral health of patients wearing removable dentures. MATERIALS AND METHODS: Eighty-eight patients were supplied with removable partial and complete dentures. The Oral Health Impact Profile (OHIP), with six subscales measuring oral health impairment and disability during daily living, the Pain Sensitivity Index, the Private Body Consciousness scale, and the Somatization Scale of the SCL-90-R, were used. RESULTS: The variables pain sensitivity, body consciousness, and somatization correlated significantly with all six OHIP subscales in removable denture wearers. In multiple hierarchic regression analyses, patient personality accounted for 38.0% of functional limitation and 41.5% of physical pain. CONCLUSION: Pain sensitivity and bodily preoccupation might be important factors in explaining the subjective oral health effects of removable denture wearing.     

Reaction of sound and demineralised dentine to Carisolv in vivo and in vitro.

OBJECTIVES: The aim of the present study was to assess the structural reaction of intact dentine to Carisolv in vivo and in vitro. METHODS: For the in vivo study occlusal cavities were prepared in 48 caries-free molars in Wistar rats (age: three months) and Carisolv-solution was placed into the cavities of 24 M for 1, 10 and 20 min. Twenty four contralateral molars served as controls and were treated with an inert liquid containing purified water, carmellose and erythrosin for corresponding periods. For the in vitro study 24 rat molars were resected en bloc and fractured to expose an area of crown dentine area. Molars were demineralised with EDTA for eight weeks to expose the collagenous dentinal matrix. One half of the specimens was then coated with Carisolv-solution for 20 min. The other half served as a control and was coated with an inert solution for 20 min. RESULTS: In the in vivo specimens no signs of pulp cell damage were observed in the experimental group. The odontoblastic processes were destroyed in proximity to the floor of the cavity but were intact in the inner portion of dentinal tubules in experimental molars and a mechanical damage was noted in the control molars. In the in vitro specimens no structural discrepancy was detected between the experimental molars and the control molars in collagen fibrils of demineralised dentine. CONCLUSIONS: Carisolv causes destruction of cellular components of odontoblastic processes but does not attack healthy collagen fibrils.     

Efficiency of the polymer bur SmartPrep compared with conventional tungsten carbide bud bur in dentin caries excavation

SmartPrep is a rotating instrument for dentin caries excavation made from a special polymer. The manufacturer's product information stated that SmartPrep removes carious dentin selectively. This in vitro study compared the efficiency of SmartPrep with conventional tungsten carbide bud burs. Fifty extracted teeth were split in the center of a carious lesion. The 100 specimens were randomly divided into five groups. Five dentists were asked to excavate 10 teeth each: one half with SmartPrep and the corresponding half with conventional bud burs. The time needed for the caries excavation was measured. Subsequently, histological specimens were produced from all cavities and analyzed by light-microscope after Mallory-Azan-staining. The thickness of the remaining caries was measured (< 1 mm or > 1 mm). The time expended was analyzed using the paired t-test. The results were analyzed for the remaining caries and thickness of the carious layer for every tooth, using the non-parametric Wilcoxon test for combined random samples. A binary logistical regression was performed to determine the influence of the three variables (tooth, sections or bur) on the criteria "caries" or "carious layer thickness (> 1 mm)." The average time to excavate a cavity with SmartPrep was 208.1 seconds, and it was 228.32 seconds with conventional bud burs. The difference between the recorded times was not statistically significant (p > 0.05). In 37 of 50 teeth, the number of carious sections was higher in the SmartPrep group than in the bud bur group. In nine teeth, the quantity of carious sections was higher in the bud bur group than in the SmartPrep group. Four teeth showed no difference in the number of carious sections. The results were statistically significantly different (p < 0.001). In 30 teeth, the number of carious sections with a carious layer thicker than 1 mm was higher in the SmartPrep group compared with the bud bur group. In nine teeth, the number of carious sections was higher in the bud bur group than in the SmartPrep group. Eleven teeth showed no difference in thickness of the carious dentin layer. These results were statistically significantly different (p = 0.003). Binary logistical regression showed that only the variable "bur" (bud bur or SmartPrep) influenced the results concerning the criterion "caries" (p < 0.001).