Although aluminum itself was reported to prevent dental caries, previous in vitro studies reported that the aluminum level in the whole saliva of children was independent of caries prevalence. Purposes of this study were to compare the elution levels of aluminum and calcium from deciduous enamel into acidic artificial saliva, and determine whether the degree of aluminum elution reflects individual caries risk. One hundred and eleven extracted human deciduous teeth were collected. Concentrations of aluminum and calcium eluted from sound regions of enamel into artificial saliva (pH 6.2 or 5.5) were determined using atomic absorption spectrophotometry. One hundred and four and 108 available data samples were obtained for aluminum and calcium evaluation, respectively, and were compared based on the sex, tooth type, caries history, and the number of the donor’s carious teeth at each pH. Calcium elution was not affected by the sex; however, more aluminum was eluted from boys’ than from girls’ teeth at pH 5.5. The aluminum release depended on the tooth type, and was significantly higher in incisors than in molars at a pH of 5.5. In relation to the caries history, aluminum (at pH 5.5) and calcium (at pH 6.2) dissolved more from sound regions of the enamel of caries-experienced teeth than from the enamel of teeth without caries experience. Moreover, aluminum markedly dissolved from enamel in artificial saliva at both pH 6.2 and 5.5 when the donor had more carious teeth, regardless of the presence or absence of caries experience in the sampled teeth. There is a possibility that the rate of aluminum elution from enamel into acidic fluid reflects individual caries sensitivity.

We previously reported that senior aged people display reduced stereognostic efficiency of the tongue compared to the young adults, and suggested the feasibility of getting over this situation applying the training protocol mentioned by us. The same important issue to the development of therapy for decreased function is study on prevention of aging-dependent functional decline. Early prevention of the oral stereognostic ability decrement might be the better option while investigation of the issues should be considered during the early onset of the conditions in aged patients. This study was conducted to understand the efficiency of tongue’s stereognostic characteristics for middle-aged people with a comparative understanding with young adults. This analysis related to tongue was conducted in 78 young adults (mean age: 24.5 years) and 33 middle-agers (mean age: 50.5 years). The method applied in this study contained 20 varied shaped test pieces in the oral cavity of the subjects. The observations revealed that most of the young adults were able to identify different shaped test pieces compare to the older participants (mean correct number of responses: 16.8 and 15.2, respectively; p<0.001). Depending on the shapes the test pieces were divided into six groups. It was found that misidentification of a piece by the young participants lead to selection of similar piece belonging to the same group. Selection of pieces from other group was almost nil. On the other hand, the older participants (middle-agers) also identified test pieces less often from separate groups. Differences in degree of decrease in the stereognostic ability between middle-agers and seniors whose ability was reported previously were also discussed.

The aim of the present study was to examine the tongue’s stereognostic ability of healthy subject in the absence of visual reference objects. The stereognostic ability of the tongue was assessed by placing 10 different test pieces in the mouth, and subjects were asked to draw the shape of each test piece in their mouths, and the drawings were scored. The average score was 15.6 of 30 possible points, and scores varied among individuals. For comparison, the stereognostic ability was also measured in the presence of visual references; subjects were asked to choose the corresponding shape to each test piece in their mouths among presented pictures of the test pieces. The mean number of correct answers was 9.2 of 10 possible numbers; the presence of visual references dramatically increased the correct response rate and decreased individual variability. To examine what were other tongue functions needed for stereognosis, two-point discrimination and motor ability of the tongue were also investigated. Two-point discrimination was assessed by touching one or two points with fixed distances to the tongue, and asking the subjects to identify how many points were contacted. To assess motor activity, the time to turn over a test piece in the mouth by the tongue was measured. The stereognostic ability of the tongue in the absence of visual references was not correlated significantly with two-point discrimination or the time to turn over a test piece. In conclusion, the assessment in the absence of visual references could detect individual differences in stereognostic ability of the tongue in more detail than the assessment in the presence of visual information. The assessment method without visual information would be helpful in the diagnosis and treatment of patients with dysphagia.

BACKGROUND:The purpose of this study was to use functional magnetic resonance imaging (fMRI) to quantify changes in brain activity during experimental occlusal interference.METHODS:Fourteen healthy volunteers performed a rhythmical tapping occlusion task with experimental occlusal interference of the right molar tooth at 0 mm (no occlusion), 0.5 mm, and 0.75 mm. The blood-oxygen-level dependent (BOLD) signal was quantified using statistical parametric mapping and compared between rest periods and task periods.RESULTS:In tapping tasks with experimental occlusal interference of 0.75 mm or 0.5 mm, there was clear activation of the contralateral teeth-related primary sensory cortex and Brodmann's area 46. At 0 and 30 minutes after removal of the experimental occlusal interference, the activation clearly appeared in the bilateral teeth-related primary sensory cortices and Brodmann's area 46. At 60 minutes after the removal of the experimental occlusal interference, the activation of Brodmann's area 46 had disappeared, and only the bilateral teeth-related primary sensory cortices were active.CONCLUSIONS:The present results suggest that adjustments for experimental occlusal interference can be objectively evaluated using fMRI. We expect that this method of evaluating adjustments in occlusal interference, combined with fMRI and the tapping task, could be applied clinically in the future.

We previously reported our investigation of the stereognostic ability of the tongue to recognize the shape and size of materials in the mouth and its clinical applications.In the present study, we observed brain activity while performing stereognostic discrimination using the tongue; the changes in levels of oxyhemoglobin (oxy-Hb), deoxyhemoglobin (deoxy-Hb), and total hemoglobin (total-Hb) in the frontal cortex area of 37 healthy individuals (18-75 years old) were measured using a functional near-infrared spectrometer with 45 channels.As an experimental task, the stereognostic test piece (TP) was placed on the center of the tongue dorsum, and subjects moved the TP for shape discrimination without letting it touch the teeth or gums.As a control task, subjects did not move the TP placed on the tongue.Stereognostic task-attributed changes in Hb levels were obtained by subtracting the Hb level of the control task from that of the experimental task.During the stereognostic task, oxy-Hb levels increased in the frontal cortex, including the prefrontal area, in most subjects.However, the results also demonstrated large individual variability.When the degree of change in Hb levels during the stereognostic task was mapped, it was found that the changes in the oxy-and total-Hb levels were similar, while the deoxy-Hb level did not change to the same degree.When subjects were divided into three groups, highly-, moderately-and mildlyincreased oxy-Hb levels, there was a significant negative correlation between age and degree of oxy-Hb level increase.The present study suggests stereognosis may be involved in several different information processing pathways, and that aging may also be a factor in the large variability we observed.

This study aimed to develop a simple method to assess the stereognostic ability of the tongue in elderly. The stereognostic ability was assessed by placing 6 differently-shaped test pieces in the oral cavity and assessing the subjects’ ability to identify the shape using their tongues. These test pieces were selected from 20 test pieces that were previously used for detailed analysis of stereognostic ability of the tongue. Stereognostic ability of the tongue in elderly subjects was compared with young adults. In total, 188 out of 198 young adults (94.9% of subjects), 26 out of 60 elderly (43.3%) not receiving care, and 1 out of 18 elderly (5.5%) receiving care could identify all 6 test pieces correctly. The most misidentified piece was a rectangular test piece and it was recognized as the test piece of the same size without corners, and vice versa. When 35 elderly who were not receiving care were assessed using either 6 or 20 test pieces, the number of correct responses for the 6 test pieces showed a significant positive correlation with those for 20 test pieces (p<0.001). These results indicate that the method using just 6 test pieces is a simple yet effective approach to assess stereognostic ability of the tongue and that it could be used in future assessments with larger and more diverse patient populations.

This study was performed to elucidate the relationship between dental caries and the levels of Sr and Ca eluted from enamel, and to examine whether these elements are useful as factors to assess caries risk. The available 103 (Sr) and 108 (Ca) samples were obtained among 111 collected deciduous teeth. The healthy regions of enamel were decalcified in artificial saliva at pH 6.2 and 5.5. The eluted levels of these elements from enamel were determined using atomic absorption spectrophotometry. Sr and Ca levels were not affected by the sex nor tooth type. Sr levels of the caries-experienced tooth (CE) group were 2.6-fold (pH 6.2) and 2.2-fold (pH 5.5) higher than those of the sound tooth (ST) group, respectively. Furthermore, the Sr levels were significantly higher in the teeth with treated than in those with untreated caries. Only at pH 6.2 was a significant difference found in Ca levels between the ST and CE groups. In the ST group, at pH 5.5, both the Sr and Ca levels significantly increased when the children had six or more carious teeth. The Sr and Ca elution levels were significantly inhibited in the teeth receiving fluoride application every 3 or 4 months compared to those that were not. These findings indicate that Sr can be an indicator of the acid resistance of teeth, and a useful factor to assess future caries risk.

Nitrite-induced transformation of 3-amino-4-monomethylamino-2',7'-difluorofluorecein (DAF-FM) to the triazol form (DAF-FMT) was studied using bacterial fraction of mixed whole saliva. The transformation at pH 7 was inhibited by SCN-, suggesting that nitrosative stresses were small in the oral cavity at the pH value as SCN- was a normal component of saliva. DAF-FMT formation was much faster at pH 5.2 than 7 and ONSCN generated by the reaction of HNO2 with SCN- mainly contributed to its formation at pH 5.2. Coffee and phenolic antioxidants inhibited the DAF-FMT formation less effectively at pH 5.2 than pH 7. The less effectiveness was discussed to be due to slow scavenging of ONSCN, which contributed mainly to the formation of DAF-FMT at pH 5.2, by coffee and phenolics. Since nitrite-induced formation of ONSCN should become faster as the pH decreases, it was suggested that nitrosative stresses to oral tissues became serious under acidic conditions.

The purpose of this study was to evaluate differences in tongue movement function between young and elderly subjects ． We developed a tongue -movement measuring device and which was used with 3 young subjects and 3 elderly subjects to measure the duratiQn of two types of tasks ( anteroposterior and lateral movements ) ． In bQth movements ， the duration measured for elderly subjects pro ▽ ed to be longer than that for young subjects ．In both groups ， the duration Df the first trial of each task was longer than that of the second or the third triaL These results suggested that tongue movement functionality for elderly subjects was lQwer than that for young subjects ， and tongue movement function was improved by repeating the sarne task，

九州歯科大学の5年次学生89名（平均年齢24.5歳）を対象に舌の立体認知能を調査した．認知能は口腔に含んだ20種類のテストピースの形状と5種類のボールのサイズを判断させる方法で評価した．舌だけの認知能をみるためにテストピースやボールが舌以外に触れないように咬合面および硬口蓋を口蓋床で覆った状態で検査を行った．口蓋を覆っていない状態でも検査したが，口蓋被覆の有無で正答率に有意差はなく，口腔内の立体認知は主に舌が担っていることが示された．20種類のテストピースのうち形状を正しく答えた平均は16.6種類だった．テストピースを四辺あるいは五辺からなる多角形群（4種），三辺からなる三角形群（3種），突起を持ち多数の辺からなる凹凸形群（3種），円形を加工した円加工形群（2種），角がなく外側に膨らむ曲線を持つ凸曲線形群（4種），角がなく内側に凹む曲線を持つ凹曲線形群（4種）に分類したが，個々の形状ついての正答率を見ると，次の4種類のテストピースが他のものより正答率が低かった:三角形群の斜辺の長い三角形，凸曲線形群の長径の長さが等しく短径の長さが異なっている3種のうち短径が中間の長さである形，凹曲線形群の中央がくびれた形の2種である．サイズ検査では小さいサイズのものは実際より小さいもの，大きいものはより大きいものと誤認する傾向が認められた．1種類のボールサイズを基準として事前に口腔に入れ，そのサイズの感覚を確認したグループと確認しなかったグループに分けた場合，基準を確認したグループの正答率の方が高かった．

displacement activity ． To begin with we designed the primers for LAMP assays to detect A actinomycetemcomitans and evaluated

In view of the role of retrograde transport for delivery of information about the nerve terminal environment, there is the possibility that the transmitter accumulation at synapse may cause some changes of retrograde transport in order to inform the neuronal cell body about the changes in the terminal environmental situation. To examine this possibility, we measured the amounts of retrograde transport of HRP in the masseter motoneurons of rats with or without administration of acetylcholinesterase inhibitors. Three kinds of inhibitors were used : diisopropyl fluorophosphate, eserin, neostigmine. The rats were administered one of inhibitors with atropine. At the same time, HRP was injected into the bilateral masseter muscles. In the brain section with HRP reaction, the amount of HRP reaction products in the masseter motoneuron was quantitatively measured using an image processing system. The amounts of HRP reaction products in the masseter motoneurons of rats with administration of any inhibitors were significantly higher than those in the control animals. These results suggested that accumulation of the transmitter acetylcholine at synapse of neuromuscular junction increased retrograde transport of HRP in the masseter motoneuron of rat.

excellent through sevenmonth observation ， indicating that the CO ， laser technique might accelerate the healing and bone regeneration ．