Effects of basic fibroblast growth factor on cultured rat and human submandibular salivary gland cells

Basic fibroblast growth factor (bFGF) is a strong mitogen for most mesoderm- and ectoderm-derived cells. Although bFGF exists in rat and human salivary glands, its physiological role in those glands is unknown. In this study, the effects of bFGF were investigated in monolayer culture of normal rat and human submandibular gland cells. Epithelial cells from rat and human submandibular glands were cultivated with the aid of 3T3 cells as a feeder layer. The effects of different concentrations of bFGF on the second passage of these cultured cells were examined. In both the rat and human cells, the percentage of bromodeoxyuridine (BrdU)-positive cells gradually increased up to 50 ng/ml, and then increased sharply at 100 ng/ml. However, at concentrations higher than 100 ng/ml, the percentages of BrdU-positive cells reached a plateau. In both rat and human cells, total cell numbers at 100 ng/ml bFGF were significantly higher than those of the control group from culture day 4. On the other hand, the morphology of the cultured cells showed no difference either with or without bFGF. These results indicate that a major effect of bFGF on salivary gland epithelial cells is to act as a mitogenic stimulus.     

Ultrastructural differentiation in the distal ends of ameloblasts from the presecretory zone to the early secretory zone

Morphological differentiation of the distal ends of ameloblasts (AMs) from the late presecretory to early secretory zones of the rat upper incisor was studied by electron microscopy. Preameloblasts (PAs) showed a high columnar shape, with the nucleus located in the basal portion. The Golgi apparatus occupied the supranuclear region with type-1 vesicles, and microvilli were present at the distal cell membrane. Coarse-textured material was observed inside the type-1 vesicles and in the lateral intercellular spaces as well as along the distal cell membrane, whereas fine-textured material was found along the distal cell membrane. Near the region of initial enamel formation, large matrix islands were found in the lateral intercellular space. A thin electron-dense layer was observed on the dentin surface. This layer might have occurred as a result of diffusion after degradation of the coarse- or fine-textured material into a finer substance in the extracellular spaces. In the region of initial enamel formation, the distal cell membrane of AMs was flat, but shallow and narrow membrane invaginations were associated with the cell membrane close to the matrix islands. In the region of inner enamel formation, a cone-shaped Tomes' process was formed between large matrix islands which had developed in the intercellular spaces between the lateral portions of the distal ends of AMs. It was considered that the membrane invaginations which had existed at the distal end of PAs moved lower toward the distal terminal bar, thereafter becoming microvilli.     

Correction of recurrent dislocation of the mandible in elderly patients by the Dautrey procedure

Twelve patients with recurrent mandibular dislocation, 11 of whom were over 50 years old, were treated by the Dautrey procedure using a temporal approach. None experienced recurrence or developed complications such as restriction of mouth-opening, paresis of the facial nerve, or pain in the temporomandibular joint during a follow-up period that ranged from 1.5 to 8 years.     

Effects of Nd:YAG and CO2 laser treatment and ultrasonic scaling on periodontal pockets of chronic periodontitis patients

BACKGROUND: The aim of the present study was to compare the effectiveness of Nd:YAG and CO2 laser treatment to that of ultrasonic scaling used as monotherapies by examining clinical parameters, subgingival microflora, and interleukin-1 beta (IL-1beta) in gingival crevicular fluid (GCF). METHODS: Eighteen patients, each of whom had 2 or more sites with probing depth measuring > 5 mm, were included this clinical trial. The 41 sites were randomly assigned treatment with either Nd:YAG laser alone (n = 14, 100 mj, 20 pps, 2.0 W, 120 seconds), CO2 laser alone (n = 13, 2.0 W, 120 seconds), or ultrasonic scaling alone (n = 14, maximum power, 120 seconds). At baseline and at 1, 4, and 12 weeks, clinical measurements (plaque index, PI; gingival index, GI; probing depth, PD; clinical attachment level, CAL; and bleeding on probing, BOP) were performed and subgingival plaque and GCF sampled. A quantitative analysis of Porphyromonas gingivalis was carried out using real-time polymerase chain reaction (PCR) procedures. The amounts of IL-1beta were estimated by an enzyme-linked immunosorbent assay (ELISA). RESULTS: Decreased inflammation and PD were observed in all 3 groups after treatment. A microbiological analysis indicated significant decreases in P. gingivalis in the Nd:YAG and scaling groups at 1, 4, and 12 weeks compared to baseline (P < 0.05). The amount of GCF significantly decreased in the Nd:YAG and scaling groups at 12 weeks. The amount of IL-1beta increased in the CO2 group from baseline to 1 week (P < 0.05). The Nd:YAG group tended to show a decrease in IL-1beta from 1 to 12 weeks, although these data were not statistically significant. CONCLUSIONS: Our data suggest that Nd:YAG laser and ultrasonic scaling treatments showed significant improvements regarding the clinical parameters and subgingival microflora compared to the baseline, but no significant difference was observed between the 3 groups.     

Porphyromonas gingivalis promotes murine abdominal aortic aneurysms via matrix metalloproteinase-2 induction

Aoyama N, Suzuki J, Wang D, Ogawa M, Kobayashi N, Hanatani T, Takeuchi Y, Izumi Y, Isobe M. Porphyromonas gingivalis promotes murine abdominal aortic aneurysms via matrix metalloproteinase‐2 induction. J Periodont Res 2011; 46: 176–183. © 2010 John Wiley & Sons A/S Background and Objective: Abdominal aortic aneurysm (AAA) is a common and lethal disorder, and MMPs are highly expressed in AAA lesions. Large numbers of periodontopathic bacteria have been reported to be present in specimens obtained from the aortic walls of patients with an AAA. The purpose of this study was to analyze the influence of periodontopathic bacteria on AAA dilatation. Material and Methods: AAAs were produced in mice by the periaortic application of 0.25 m CaCl₂, and NaCl was used as a control. The mice were inoculated once weekly with live Porphyromonas gingivalis, live Aggregatibacter actinomycetemcomitans or vehicle. Results: Four weeks after the periaortic application of either CaCl₂ or NaCl, a significant increase was observed in the aortic diameter of P. gingivalis‐challenged mice compared with the vehicle control mice (p < 0.05), whereas there was no statistically significant increase in the aortic diameter of the A. actinomycetemcomitans‐challenged mice. Immunohistochemical analysis found significantly higher numbers of CD8‐positive and MOMA2‐positive cells and significantly higher levels of MMP‐2 in the aneurysmal samples of P. gingivalis‐challenged mice compared with control mice. Live P. gingivalis promoted a significant proliferation of splenocytes in comparison with P. gingivalis‐lipopolysaccharide and live A. actinomycetemcomitans (p < 0.05). Conclusion: These findings demonstrate that challenge with P. gingivalis, but not with A. actinomycetemcomitans, can accelerate, or even initiate, the progression of experimental AAA through the increased expression of MMPs.     

Conscious survey of dental patients. 1. Questionnaire related to general dentistry (in the case of the new patients of the Nippon Dental University Hospital)

Increased information on dentistry in the mass media in recent years may have caused changes in patients' attitudes toward dental care. To better understand patient' attitudes, we conducted a questionnaire survey of patients on the first visit to our hospital. Of 384 responses, 196 were eligible for statistical analysis. The following findings were obtained. 1. Among the motives for visiting a dental clinic, "Manifestation of pain or symptoms" was given by majority (85.7%) of respondents, followed by "detection of abnormality" (20.4%). The percentage of patients wanting treatment of "any part suggested by the dentist" was highest (35.7%), followed by those expecting "treatment including cleaning" (30.1%). The above results indicate that patients still tend to visit a clinical after subjective symptoms appear and leave the content of treatment to the dentist. However, an increasing number of patients appear to be concerned with their oral condition and visit a clinic before manifestation of symptoms. 2. Among factors in selecting their dentist, "expertise" obtained the highest percentage, 87.2%, followed by "providing prompt treatment" (38.8%) and "trying to avoid pain" (32.1%), in that order. Dissatisfaction with dentists was described as "no explanation of treatment" in 57.1%, "lack of sympathetic attitude" in 38.3% and "easily resorts to tooth extraction" in 35.4%. These results suggest that patients expect good human relations with their dentists, sufficient explanations of treatments and sympathetic consideration, as well as expertise. 3. The majority of patients (85.7%) hoped to receive instructions on oral hygiene and to be increased interest in information above prophylaxis. Meeting their needs will remain a future issue for dentists.     

A comparative study on the responses of blood vessels of oral mucosa to thermal stimulation in dentulous and edentulous subjects

The purpose of this experiment was to clarify the characteristic changes of vasculature in edentulous alveolar mucosa and the effect of wearing a complete denture during sleep. Thermal stimulations were applied to the oral mucosa of five normal subjects and five completely edentulous patients and the responses of blood vessels were observed using both Impedance Plethysmography (IMP) and Reflection Photoelectric Plethysmography (RPP). Quantitative comparisons were made between edentulous patients and dentulous normal subjects, and between patients wearing complete dentures during sleep and those who do not. The following results were obtained. 1) The responses of blood vessels were divided into four groups. Type 1 showed dilatation in IMP and RPP. Type 2 showed dilatation but had late initial rising in IMP. Type 3 showed initial contraction in either or both IMP and RPP, and followed by dilatation few seconds later. Type 4 showed no changes in RPP but dilatation in IMP. 2) There was definite difference between edentulous and dentulous subjects in the frequency of exhibition of each type. Especially for the edentulous patients type 4 was observed in all stimulation temperature. 3) For the dentulous subjects there were more cases showing responses of RPP in digital apex than those do not. This was most conspicuous at the 50 degrees C stimulation. However for the edentulous patients there were about equal number of each cases. 4) The responses of blood vessels for both dentulous and edentulous subjects became greater and blood volume increased both with time at each temperature and as the stimulation temperature were raised. However the increase in the response was greater for the edentulous patients when the stimulation temperature was raised from 0 degrees C to 50 degrees C. 5) The responses of blood vessels became greater after two weeks when complete dentures were worn during sleep at night. And when dentures were not worn during sleep the responses decreased to a level lower than what it used to be after three weeks. 6) From the above results it was suggested that oral mucosa of the edentulous patients were losing their sensitivity due to wearing complete dentures and were not receiving as much effect of the contractile control from body as the dentulous subjects. It was also suggested that wearing denture during sleep at night cause inflammation of oral mucosa and increase the metabolism of tissue in edentulous patients.