Antiviral, antibacterial and vitamin C-synergized radical-scavenging activity of Sasa senanensis Rehder extract.

Sasa senanensis Rehder extract (SE) showed slightly higher cytotoxicity against human squamous cell carcinoma cell lines and human glioblastoma cell lines, as compared with human oral normal cells (gingival fibroblast, pulp cell, periodontal ligament fibroblast), and was more cytotoxic to human myelogenous and T-cell leukemia cell lines. SE showed a bacteriostatic effect on Fusobacterium nucleatum and Prevotella intermedia, but almost completely eliminated hydrogen sulfide (H2S) and methyl mercaptan (CH3SH) produced by these bacteria. SE protected human T-cell leukemia MT-4 cells from the cytopathic effect of human immunodeficiency virus (HIV) infection, and its anti-HIV activity was much higher than that of tannins and flavonoids, comparable with that of natural and synthetic lignins. SE also protected the MDCK cells from the cytopathic effect of influenza virus infection. SE synergistically enhanced the superoxide anion and hydroxyl radical-scavenging activity of vitamin C. The present study suggests the functionality of SE as a complementary alternative medicine.

Determination of genes involved in the early process of molar root development initiation in rat by modified subtractive hybridization.

Rat molars and incisors have different root patterning mechanisms: the former form a multirooted pattern while the latter form a single-rooted analogue. But the genetic signals that control root patterning are poorly understood. In this study, to identify the special molecular signals which may lead to the molar root development, we firstly observed that at embryonic day 19 the molar and the incisor began differentially developing: the molar formed double-layered cells of the root sheath while the incisor formed a cervical loop. By using the subtractive hybridization method, we successfully constructed a subtraction cDNA library of the rat molar and incisor tissues. Differentially expressed gene clones were evaluated by dot-blot and sequencing. Sel1l, Nfic, Edar, GATA6, and some novel genes were found differentially expressed, which were strongly related the tooth root patterning. It is anticipated that further study of genes identified will provide insights into their specific roles in the tooth root patterning.

In vitro study of the effects of fluoride-releasing dental materials on remineralization in an enamel erosion model.

OBJECTIVES: This study was conducted to compare the remineralization effects of five regimens on the loss of fluorescence intensity, surface microhardness, roughness and microstructure of bovine enamel after remineralization. We hope that these results can provide some basis for the clinical application of these materials. METHODS: One hundred bovine incisors were prepared and divided into the following five groups, which were treated with distinct dental materials: (1) Clinpro™ XT varnish (CV), (2) F-varnish (FV), (3) Tooth Mousse (TM), (4) Fuji III LC(®) light-cured glass ionomer pit and fissure sealant (FJ) and (5) Base Cement(®) glass polyalkenoate cement (BC). Subsequently, they were detected using four different methods: quantitative light-induced fluorescence, microhardness, surface 3D topography and scanning electron microscopy (SEM). RESULTS: The loss of fluorescence intensity of CV, BC and FJ groups showed significant decreases after remineralization (p<0.05). The microhardness values of the BC group were significantly higher than those of the other groups (p<0.05) after 6 weeks of remineralization. The CV group's surface roughness was significantly lower than those of the other groups after 6 weeks of remineralization (p<0.05). Regarding microstructure values, the FV group showed many round particles deposited in the bovine enamel after remineralization. However, the other four groups mainly showed needle-like crystals. CONCLUSIONS: Glass ionomer cement (GIC)-based dental materials can promote more remineralization of the artificial enamel lesions than can NaF-based dental materials. Resin-modified GIC materials (e.g., CV and FJ) have the potential for more controlled and sustained release of remineralized agents. The effect of TM requires further study.

Effect of three fluoride compounds on the growth of oral normal and tumor cells.

AIM: Comparative study of the growth inhibition by different types of fluoride compounds used in dentistry has been limited. We investigated the effects of sodium fluoride (NaF), diammine silver fluoride [Ag(NH3)2F] and 5-fluorouracil (5-FU) on the growth of eleven human normal and tumor cells in total. MATERIALS AND METHODS: Viable cell number was determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Apoptosis induction was evaluated by caspase-3 activation and DNA fragmentation. Fluoride was determined using a fluoride-specific electrode. RESULTS: All compounds had little or no growth stimulating effect (hormesis) on all cells. Ag(NH3)2F exhibited the highest cytotoxicity towards both normal and tumor cells. 5-FU had the selective cytostatic activity towards oral squamous cell carcinoma cell lines, whereas NaF was selectively cytotoxic towards glioblastoma cell lines. None of the compounds induced internucleosomal DNA fragmentation and only 5-FU induced slight activation of caspase-3 in an oral squamous cell carcinoma cell line (HSC-2). Cytotoxicity of fluoride compounds was not reduced by superoxide dismutase and catalase, reducing the possibility of the involvement of reactive oxygen species in the mechanism of action. Approximately 0.01-0.09% initially added NaF was recovered from the cells, whereas the cellular uptake of Ag(NH3)2F and 5-FU was below the detection limit. CONCLUSION: Cytotoxicity of fluoride compounds may not be directly linked to their tumor specificity nor to their apoptosis-inducing activity.

Al and Fe levels in mixed saliva of children related to elution behavior from teeth and restorations.

OBJECTIVES: The levels of trace elements in mixed saliva were not well-defined. This study was performed to determine Al and Fe concentrations in mixed saliva of children and to investigate the relationship between these levels and dental caries. METHODS: Among 562 collected mixed saliva specimens, 514 and 548 samples for analyses of Al and Fe levels were obtained, respectively. The Al and Fe concentrations were determined using flameless atomic absorption spectrometry. RESULTS: The Al and Fe concentrations in children without a history of caries were 0.093±0.136 and 0.121±0.128 µg/mL, respectively. The Fe level depended on sex. The Fe level in girls who experienced caries was significantly higher than that without caries history. The Al and Fe levels were significantly higher in children with treated caries than children without caries history. The Fe concentrations were affected by restoration type. Composite resin increased the Fe level significantly especially in girls, and the Fe level was also higher in boys treated with both composite resin and metal restorations. In children without caries history, the Al level was inversely proportional to the number of deciduous teeth and increased with the number of permanent teeth. In contrast, the Fe level showed the reverse tendency. CONCLUSIONS: The Fe level in mixed saliva of children was influenced by the restoration type. It was suggested that Al was eluted more from sound permanent teeth than sound deciduous teeth, while Fe was eluted in the opposite manner.

Diurnal changes in salivary amino acid concentrations.

It has been suggested that the features of saliva (e.g. fluidity, secretion and amino acid concentration) reflect physiological and psychological state of primates as well as subprimates, however, studies which revealed the relationship between the circadian rhythm and the concentrations of salivary amino acids have been limited. In order to better understand their physiological role, diurnal changes of salivary amino acids were investigated in three undergraduate students. Salivary amino acids were recovered after deproteinization with 5% trichloroacetic acid and determined by an amino acid analyzer. Most amino acids, except for methionine, cysteine and asparagine, were detected in the saliva. The intake of lunch or amino acid supplement transiently increased the salivary amino acids, and in the latter case, the amino acid levels returned to baseline within 10 minutes. Physical exercise also slightly elevated the salivary amino acid levels. During the university examination period, the secretion of saliva was slightly, but not significantly, increased, accompanied by the elevation of glycine, alanine, ornithine, histidine and threonine, and the decline of lysine, leucine, aspartic acid and hydroxyproline. Salivary amino acid levels may be useful to evaluate stressful conditions.

Clinical, pathological and genetic evaluations of Chinese patients with autosomal-dominant hypophosphatasia.

OBJECTIVES: Hypophosphatasia (HPP) is an inherited disorder characterised by defective bone and tooth mineralisation and deficient serum and bone alkaline phosphatase activity, and it results from mutations in alkaline phosphatase (ALPL) encoding tissue-nonspecific alkaline phosphatase (TNAP). The objective of the present work was to explore the correlations between genotype and phenotype in a Chinese family affected by autosomal-dominant HPP. DESIGN: We examined all individuals of a HPP family by clinical and radiographic examinations as well as laboratory assays. Furthermore, a prematurely exfoliated tooth was observed histopathologically. Based on the clinical and pathological manifestations, the causative gene ALPL was selected for further analysis and screened for mutations. RESULTS: The proband presented the characteristic clinical features of childhood HPP such as rachitic skeletal changes, early loss of primary teeth, and short root anomalies of the permanent teeth. Histopathological evaluation of a tooth revealed a "shell" structure, severe mineralisation defects of dentin, and an absence of cementum. The patient's mother and grandfather were clinically diagnosed with adult HPP. The family showed autosomal-dominant moderate hypophosphatasia. DNA sequencing and analysis revealed a novel missense mutation (c.251A>T) in exon4 of ALPL. This mutation (p.E84V) is located in the secondary structure of TNAP's homodimer interface, and it was predicted to have a dominant negative effect. CONCLUSION: Our findings suggest the missense transversion (c.251A>T, p.E84V) should be responsible for the HPP phenotype in this Chinese family.

Multiple biological complex of alkaline extract of the leaves of Sasa senanensis Rehder.

Previous studies have shown anti-inflammatory potential of alkaline extract of the leaves of Sasa senanensis Rehder (SE). The aim of the present study was to clarity the molecular entity of SE, using various fractionation methods. SE inhibited the production of nitric oxide (NO), but not tumour necrosis factor-α by lipopolysaccharide (LPS)-stimulated mouse macrophage-like cells. Lignin carbohydrate complex prepared from SE inhibited the NO production to a comparable extent with SE, whereas chlorophyllin was more active. On successive extraction with organic solvents, nearly 90% of SE components, including chlorophyllin, were recovered from the aqueous layer. Anti-HIV activity of SE was comparable with that of lignin-carbohydrate complex, and much higher than that of chlorophyllin and n-butanol extract fractions. The CYP3A inhibitory activity of SE was significantly lower than that of grapefruit juice and chlorophyllin. Oral administration of SE slightly reduced the number of oral bacteria. When SE was applied to HPLC, nearly 70% of SE components were eluted as a single peak. These data suggest that multiple components of SE may be associated with each other in the native state or after extraction with alkaline solution.

Influence of the location of the parotid duct orifice on oral clearance.

OBJECTIVES: To determine the location of the parotid duct orifice in relation to the maxillary molars and its influence on oral clearance on the buccal surfaces of the maxillary molars. METHODS: A 2-mm hole was made at the centre of an adhesive therapeutic agent for aphthous stomatitis and the agent was placed on the mucosa so that the hole matched the parotid duct orifice. To locate the orifice, an impression of the buccal tooth surfaces and mucosa around the agent was taken with the teeth in centric occlusion. To evaluate the oral clearance rate, 12 subjects who displayed the parotid duct orifice within 1S.D. of the mean values obtained from the original 35 subjects were selected. 1% agar containing 1 mol/l potassium chloride was placed into three cylinders positioned horizontally, 6mm apart, in an acrylic holder centred over the mean duct location. The diffusion chambers were taken from the mouth at selected time intervals and the gel transferred quantitatively to flasks containing 300 ml of 100 ppm NaCl, which was assayed for potassium by atomic absorption spectrophotometry. Half-times for clearance were calculated. RESULTS: The mean location of the parotid duct orifice was -0.4 mm (range -7.5 to +6.1 mm) mesial to the contact surface between the maxillary first and second molars (where negative values indicate mesial and positive values distal) and 7.2 mm (range +3.8 to +10.4 mm) above a line touching the buccal cusps of the upper molars. The clearance half-time values were shortest for the central cylinder whether salivary flow was unstimulated or stimulated and when flow was unstimulated the clearance half-time was shorter for the mesial than the distal cylinder. CONCLUSION: The degree of individual variation in the location of the parotid duct orifice is great and its exact location will markedly affect oral clearance at different positions on the buccal surfaces of the upper molars.

An elderly case of type 2 diabetes which developed in association with oral and esophageal candidiasis.

A 75-year-old woman who had been healthy except for mild glycemia and lipidemia discovered three and a half months before admission experienced severe dysphagia secondary to oral and esophageal candidiasis. She eventually developed diabetic hyperosmolar syndrome and ketoacidosis. Since anti-GAD antibody was negative and her diabetes was controlled with a moderate dose of insulin, we made a diagnosis of type 2 diabetes. Her only risk factors for candidiasis were hyperglycemia, age, and continuous denture use. The fact that her diabetes developed in association with oral candidiasis supports the hypothesis that there is a bidirectional interrelationship between diabetes and oral infection.

Basic study on vibrations during tooth preparations caused by high-speed drilling and Er:YAG laser irradiation.

BACKGROUND AND OBJECTIVES: An Er:YAG laser effectively removes dental hard substance, and causes less pain during tooth preparations than high-speed drilling. This laser was introduced to eliminate the noise, vibration, pressure, and heat associated with the high-speed drilling. However, the difference in tooth vibration caused by the Er:YAG laser and the high-speed drill is unclear. Therefore, the aim of this study was to evaluate tooth vibration obtained with the Er:YAG laser and high-speed drill. STUDY DESIGN/MATERIALS AND METHODS: Each of the five extracted permanent upper first premolars were built up in a plaster box. In this study, a silicone impression material was selected to simulate periodontal tissue. The vibration speed was measured by using a laser Doppler vibrometer. RESULTS: The Er:YAG laser irradiation energy was 50, 100, 145, 199, 300, and 350 mJ. As irradiation energy increased, vibration of the tooth also rose; a high-correlation coefficient was observed between them. We found that only a small amount of the tooth vibration occurred with the Er:YAG laser preparations. The mean vibration speed and standard deviation with the laser were 166 +/- 28 microm/second when the output energy was 145 mJ, whereas those with the high-speed drill were 65 +/- 48 mm/second. The frequency characteristic approached 230 Hz and 5 kHz, respectively. CONCLUSIONS: These results show that the high-speed drilling causes greater tooth vibration and has a frequency spectrum near the high sensitivity of hearing compared to the Er:YAG laser. This suggests a potential factor in provoking pain and displeasure during tooth preparation. Future study to examine the relationship of pain and amount of tooth vibration will be planned.