Natal and Neonatal Teeth: A Case Report and Mecanistical Perspective.

The presence of teeth on babies earlier than four months is a rare condition. Therefore, adequate treatment for each case should be instituted as soon as possible, considering that certain complications may arise. This report describes a rare case in which a newborn baby required the extraction of two mobile mandibular natal teeth to prevent the risk of aspiration. After two years, the clinical re-evaluation showed a residual tooth instead of a temporary one. This case report shows that adequate diagnosis should include a radiographic examination to determine whether these teeth are components of normal or supernumerary dentition, as well as further investigations on the relationship with the adjacent teeth. Another important aspect highlighted in this case report is the need for a post-extraction curettage of the socket in order to reduce the risk of ongoing development of the dental papilla cells.

Favorite Music Mediates Pain-related Responses in the Anterior Cingulate Cortex and Skin Pain Thresholds.

PURPOSE: Music therapy is widely used to enhance well-being, reduce pain, and distract patients from unpleasant symptoms in the clinical setting. However, the degree to which music modulates pain perception is unknown. The medial pain pathway including the limbic system is associated with emotion, but how music alters pathway activity is unclear. The aim of the study was to investigate pain thresholds and pain-related responses in the anterior cingulate cortex (ACC) and whether they were modulated when subjects listened to their favorite music genre. SUBJECTS AND METHODS: First, 30 subjects were examined for left forearm pain threshold using electrical stimulation with Pain Vision PS-2011N. The pain thresholds with and without music were compared. Second, when an 80-µA current from Pain Vision was applied to the left ankle of eight women, the pain-related responses of the ACC with and without music were observed with functional magnetic resonance device (fMRI). The changes in the pain-related activity in both parameters were discussed. RESULTS: The median pain threshold with favorite music was 38.9 µA, compared to 29.0 µA without, which was significantly different (p<0.0001). The men's thresholds were significantly higher than women's both with music (p<0.05) and without music (p<0.01). The pain threshold in women was more strongly affected by music than in men. The fMRI results showed that the pain-related response in the ACC in five of eight subjects was attenuated while they listened to their favorite music. No change was observed in the other three subjects. CONCLUSION: The present findings suggest that pain perception might be strongly affected by listening to favorite music, possibly through modulation of pain-related responses in the ACC.

Minireview on the Connections between the Neuropsychiatric and Dental Disorders: Current Perspectives and the Possible Relevance of Oxidative Stress and Other Factors.

Although the connections between neuropsychiatric and dental disorders attracted the attention of some research groups for more than 50 years now, there is a general opinion in the literature that it remains a clearly understudied and underrated topic, with many unknowns and a multitude of challenges for the specialists working in both these areas of research. In this way, considering the previous experience of our groups in these individual matters which are combined here, we are summarizing in this minireport the current status of knowledge on the connections between neuropsychiatric and dental manifestations, as well as some general ideas on how oxidative stress, pain, music therapy or even irritable bowel syndrome-related manifestations could be relevant in this current context and summarize some current approaches in this matter.

Effect of single-nucleotide polymorphisms in TRPV1 on burning pain and capsaicin sensitivity in Japanese adults.

Transient receptor potential vanilloid 1 (TRPV1) is a nonselective cation channel that is expressed in the sensory neurons and responds to various noxious stimuli including heat and capsaicin. The molecular properties of TRPV1 have been clearly examined; however, there are obvious individual differences in human sensitivity to thermal stimuli and capsaicin. Here, we examined the possibility that different genome sequence of human TRPV1 caused the different sensitivity to heat or capsaicin. The sensitivities to burning pain and capsaicin of Japanese adult subjects were compared with their TRPV1 genome sequence, and we detected 6 single-nucleotide polymorphisms and 11 single-nucleotide polymorphisms related to burning pain and capsaicin sensitivity, respectively. In particular, homozygous I585V, a single-nucleotide polymorphism with amino acid substitution, significantly related to higher capsaicin sensitivity.

Functional Role of HSP47 in the Periodontal Ligament Subjected to Occlusal Overload in Mice.

We carried out an experiment to induce traumatic occlusion in mice periodontal tissue and analyzed the expression of HSP47. Continuous traumatic occlusion resulted to damage and remodeling of periodontal ligament as well as increase in osteoclasts and bone resorption. Four days after traumatic occlusion, osteoclasts did not increase but Howship's lacunae became enlarged. That is, the persistent occlusal overload can destroy collagen fibers in the periodontal ligament. This was evident by the increased in HSP47 expression with the occlusal overload. HSP47 is maintained in fibroblasts for repair of damaged collagen fibers. On the other hand, osteoclasts continue to increase although the load was released. The osteoclasts that appeared on the alveolar bone surface were likely due to sustained activity. The increase in osteoclasts was estimated to occur after load application at day 4. HSP47 continued to increase until day 6 in experiment 2 but then reduced at day 10. Therefore, HSP47 appears after a period of certain activities to repair damaged collagen fibers, and the activity was returned to a state of equilibrium at day 30 with significantly diminished expression. Thus, the results suggest that HSP47 is actively involved in homeostasis of periodontal tissue subjected to occlusal overload.

Histological Evaluation of Periodontal Ligament in Response to Orthodontic Mechanical Stress in Mice.

The purpose of the study was to determine the cell dynamics in periodontal ligament in response to mechanical stress during orthodontic movement. Following Waldo's method, a square sheet of rubber dam was inserted in between the first and second maxillary molars in 10 ddY mice leaving the stress load for 3 hours. After 3 days and at 1 week, cell count on pressure and tension sides of the periodontal ligament was determined. Furthermore, the type of cell present after mechanical stress was identified using GFP bone marrow transplantation mouse model. Immunohistochemistry was carried out at 0 min (immediately after mechanical stress), 24 hours, 1 week, 2 weeks and 6 months. Temporal changes in the expression of GFP-positive bone marrow derived cells were examined. Moreover, double immunofluorescent staining was performed to determine the type of cell in the periodontal ligament. Cell count on the tension side tremendously increased 3 days after mechanical stress. At 1 week, spindle and round cell count increased compared to the control group. These changes were observed on both tension and pressure sides. Cell count on pressure side at 3 days (22.11+/-13.98) and at 1 week (33.23+/-11.39) was higher compared to the control group (15.26+/-8.29). On the tension side, there was a significantly increased at 3 days (35.46+/-11.85), but decreased at 1 week (29.23+/-13.89) although it is still higher compared to the control group (AD+/-SD: 10.37+/-8.69). Using GFP bone marrow transplantation mouse model, GFP positive cell count increased gradually over time in 6 months. GFP positive cells were also positive to CD31, CD68 and Runx2 suggesting that fibroblasts differentiated into osteoclasts and tissue macrophages. In conclusion, mechanical stress during orthodontic movement promoted the increase in the number of cells in the periodontal ligament on both tension and pressure sides. The increase in the number of cells in the periodontal ligament is believed to be due to the migration and cell division of undifferentiated mesenchymal cells.

Cytological Kinetics of Periodontal Ligament in an Experimental Occlusal Trauma Model.

Using a model of experimental occlusal trauma in mice, we investigated cytological kinetics of periodontal ligament by means of histopathological, immunohistochemical, and photographical analysis methods. Periodontal ligament cells at furcation areas of molar teeth in the experimental group on day 4 showed a proliferation tendency of periodontal ligament cells. The cells with a round-shaped nucleus deeply stained the hematoxylin and increased within the day 4 specimens. Ki67 positive nuclei showed a prominent increase in the group on days 4 and 7. Green Fluorescent Protein (GFP) positivity also revealed cell movement but was slightly slow compared to Ki67. It indicated that restoration of mechanism seemed conspicuous by osteoclasts and macrophages from bone-marrow-derived cells for the periodontal ligament at the furcation area. It was suggested that the remodeling of periodontal ligament with cell acceleration was evoked from the experiment for the group on day 4 and after day 7. Periodontal ligament at the furcation area of the molar teeth in this experimental model recovered using the cells in situ and the bone-marrow-derived cells.

Promotion of transplanted bone marrow-derived cell migration into the periodontal tissues due to orthodontic mechanical stress.

BACKGROUND: Bone marrow-derived cells (BMCs) have abilities of cell migration and differentiation into tissues/organs in the body and related with the differentiation of teeth or periodontal tissue including fibroblasts. Then, we examined the effect of orthodontic mechanical stress to the transplanted BMC migration into periodontal tissues using BMC transplantation model. MATERIAL AND METHOD: BMC from green fluorescence protein (GFP) transgenic mice were transplanted into 8-week-old female C57BL/6 immunocompromised recipient mice, which had undergone 10 Gy of lethal whole-body-irradiation. Five mice as experimental group were received orthodontic mechanical stress using separator between first molar (M1) and second molar (M2) 1 time per week for 5 weeks and 5 mice as control group were not received mechanical stress. The maxilla with M1 and M2 was removed and was immunohistochemically analyzed using a Dako Envision + Kit-K4006 and a primary anti-GFP-polyclonal rabbit antibody. Immunohistochemically stained was defined as positive area and the pixel number of positive area in the periodontal tissue was compared with the previously calculated total pixel number of the periodontal tissue. RESULTS: The immunohistochemistry revealed that GFP positive cells were detected in the periodontal tissues, both in the experimental and control specimens. The ratio of pixel number in the examination group showed 5.77 ± 3.24 % (mean ± SD); and that in the control group, 0.71 ± 0.45 % (mean ± SD). The examination group was significantly greater than that of control group (Mann-Whitney U test: p<0.001). CONCLUSION: These results suggest that orthodontic mechanical stress accelerates transplanted BMC migration into periodontal tissues.

The endogenous opioids related with antinociceptive effects induced by electrical stimulation into the amygdala.

Pain relief is necessary and essential for dental treatments. Recently, the relationships of pain and emotion were studied, and electrical stimulation applied to the amygdala depressed the nociceptive response in the anterior cingulate cortex (ACC). Thus, the antinociceptive effects of the amygdala are elucidated, but its mechanism is not yet clarified. The present study was performed to investigate whether endogenous opioid system is related to the depression, and the quantitative changes of endogenous opioids induced by electrical stimulation to the amygdala. We investigated immunohistologically c-Fos expression to confirm the activated neurons, as well as the distribution and the amount of endogenous opioids (ß-endorphin, enkephalin and dynorphin A) in the brain using male Wistar rats, when electrical stimulation was applied to the central nucleus of the amygdala (CeA) or noxious stimulation was delivered to the peripheral tissue. c-Fos expression in the ipsilateral ACC was increased by electrical stimulation to the CeA. However, only a small amount of endogenous opioids was observed in the ACC when noxious stimulation or electrical stimulation was applied. In contrast, the amount of dynorphin A in the periaqueductal gray (PAG) was increased by electrical stimulation to the CeA, and the amount of ß-endorphin in the PAG was increased by noxious stimulation to the peripheral tissue. The results suggest that dynorphin A in the PAG induced by electrical stimulation to the CeA activate the descending antinociceptive system, and suggest that the nociceptive response in the ACC is depressed indirectly.

Newly designed gustatory test based on the number of chewing strokes required for recognition of the taste.

PURPOSE: The purpose of this study was to examine the usefulness of a new gustatory test based on the progress of mastication by counting the number of chewing strokes required for recognizing tastes. METHODS: Thirty-nine subjects (20 males and 19 females, 25.3±6.4 years old) without missing teeth were selected. Four types of newly designed test materials made from 15% gelatine were prepared, containing sucrose, sodium chloride, tartaric acid, or quinine hydrochloride. Five or six concentrations, representing weak to strong tastes, were prepared for each tastant. Subjects were instructed to chew the food, and the number of chewing strokes necessary to recognize the taste was counted. RESULTS: Female subjects recognized the sweet taste more accurately than male subjects (Friedman test: p<0.05). For each tastant of the test materials, the average number of chewing strokes (recognition threshold) was approximately 10. The frequency of correct responses and the average number of chewing strokes tended to be higher and lower, respectively, as the concentration of the taste in the test material increased (Kruskal-Wallis test: sweet p<0.01, salty p<0.01, sour p<0.01 and bitter p<0.01). CONCLUSIONS: Using the newly designed test materials, counting the number of chewing strokes necessary for recognizing the taste would be a useful index of a new gustatory test to investigate taste sensation.

Histopathological examination of newly-developed adhesive silicone denture relining material.

We aimed to evaluate the subcutaneous tissue reaction to a newly developed adhesive silicone denture relining material, SG, (Neo Dental Chemical Products Co., Ltd. Tokyo, Japan). We embedded the experimental material SG and another existing control material, Roeko Seal (RS), in the dorsal area of 22 male ddY mice. One week and 12 weeks after the embedding, the tissues surrounding the embedded materials were removed and a histopathological examination was performed. The results demonstrate that the basic histopathological aspects are the formation of granulation tissue and the change of the tissue to fibrous capsule over time. The results suggests that the newly-developed SG is safe as compared with the control RS, whose composition is similar.

Effects of deuterium oxide on Streptococcus mutans and Pseudomonas aeruginosa.

A complex aggregation of microorganisms growing on a solid substrate is termed a biofilm and is considered to be an etiological agents. Pseudomonas aeruginosa and Streptococcus mutans are representative bacteria in such biofilms. It is well known that deuterium oxide (D2O) causes toxic effects on a number of biological systems. We investigated the effects of D2O on growth and biofilm formation of P. aeruginosa and S. mutans. These bacteria were incubated in medium containing D2O (100%, 75% or 0%) at 37°C for 24hr, 48 hr or 72 hr. Growth of P. aeruginosa was inhibited by D2O within the first 48 hr. However, after 72 hr, growth rate was seen to increase in the D2O-containing medium compared with in medium without D2O. In contrast, the growth of S. mutans in the D2O medium was inhibited within 72 hr. The biofilm formation of P. aeruginosa was increased in the D2O medium. Biofilm formation of S. mutans in the D2O medium increased compared with in the medium without D2O, but this increase was only temporary in the case of P. aeruginosa. Compared to biofilm formation in 0% D2O medium marked as 100%, the biofilm formation rate of S. mutans in 75% D2O medium was 143% at 24 hr, 146% at 48 hr and 130% at 72 hr. In other D2O concentration media biofilm formation was lower. In 100% D2O medium, biofilm formation rate decreased from 114% at 24 hr to 56% at 72 hr. The biofilm formation rate of P. aeruginosa in 100% D2O medium was 172% at 24 hr, but decreased to 88% at 72 hr. Biofilm formation of P. aeruginosa in 75% and 0% D2O media showed no significant difference. We consider that these results were due to stress or alteration in bacterial metabolisms.

[Relationship between condylar displacement during clenching and condylar guide inclination].

PURPOSE: Many studies have reported the relationship between facial morphology and stomatognathic functions. The steepness of the articular eminence is an important morphological factor to determine the mandibular movement or mandibular positioning. The present study analyzed the relationship between the condylar displacement during clenching and the condylar guide inclination related to simulated loss of posterior occlusal support. METHODS: Nineteen clinical residents (4 females and 15 males, 24-31 years old) with healthy natural dentitions were recruited as subjects. To change the posterior occlusal support, occlusal splints fitted to maxillary dental arches were cut in sequence from the posterior toward the anterior side. The condylar displacements during maximum voluntary clenching under every occlusal condition were measured using a mandibular movement analyzing system with six-degrees of freedom. The sagittal condylar guide inclination was also measured using the same apparatus. RESULTS: 1. A greater loss of posterior occlusal support was associated with increased displacement distance of both condyles, however these values varied with the subject. 2. A significant positive correlation was observed between the displacement distance without splint and the relative displacement distance with splint (difference between before and after loss of occlusal supports). 3. A significant negative correlation was observed between the displacement distance without splint and the sagittal condylar guide inclination, and was also observed between the relative displacement distance with splint (above-mentioned) and the sagittal condylar guide inclination. CONCLUSION: These results suggest that the sagittal condylar guide inclination is an important factor in condylar displacement during clenching.

Dopamine beta-hydroxylase like immunoreactive cells in the frog taste disc.

We immunohistochemically examined the existence of dopamine beta-hydroxylase (DBH), a noradrenalin (NA)-synthesizing enzyme from dopamine, in the taste disc of frog, Rana catesbeiana. DBH-like immunoreactive cells were located in the intermediate layer in the taste disc; the cells showed an apical process reaching the surface of the disc and one or several basal processes. Cells with a thick apical process and those with a thin apical process were both immunoreactive: these cells corresponded to type II and III receptor cells of the frog taste disc. Immunoreactive granules were observed in the cytoplasm of those cells. In the frog taste disc, only type III cells are reported to have afferent synapses with the nerve via basal processes but those basal processes have not been reported in type II cells. In the present study, we found that type II-like cells possessed a long basal process extending toward the basal lamina. Mucous (type Ia) cells, wing (type Ib) cells, and glia-like sustentacular (type Ic) cells were all immunohistochemically unreactive. The present observations support the argument that NA (or adrenalin) may work as a chemical transmitter in the frog taste organ.

Gamma knife radiosurgery targeting protocols for the experiments with small animals.

BACKGROUND/AIMS: Manipulation of brain functions via Gamma Knife (GK) irradiation would have numerous applications in clinical and experimental neurology. METHODS: Alteration of brain functions in the unilaterally irradiated striatum was indexed through monitoring freely moving rat behaviors. Spontaneous activity and rotations on the apomorphine test, which can detect dopaminergic function imbalance, were indexed employing our behavior tracking system. The spatial distribution of necrotic lesions was explored using serial sections, and was assumed to represent the real foci of the GK target. RESULTS: Distinct behavioral alterations corresponded to the precise locations of the lesions in various areas of the basal ganglia. Displacement of the irradiation sites in the anteromedial direction increased spontaneous activity, and posterolateral shift provoked circling behavior on the apomorphine test. CONCLUSION: Accurate positioning of the target is crucial for experimental GK irradiation locally focused on domains of a small brain such as that of the rat. Here, we propose a protocol for converting the 'intended' focus, based on brain map coordinates, to a 'planned' focus on the MR imaging coordinate system with the Régis-Valliccioni stereotactic frame.

Influence of condylar guide inclination on condylar positioning during clenching.

The relationship between the steepness of the articular eminence and the condylar positioning during clenching was investigated in 19 volunteers with natural dentitions. The condylar positioning during maximal voluntary contraction was measured using a mandibular movement analysis system with six degrees of freedom. The sagittal condylar guide inclination was also measured using the same apparatus. A significant negative correlation was observed between the sagittal condylar guide inclination and the distance of ipsilateral condylar positioning. This result suggests that the steepness of the articular eminence is an important factor in condylar positioning during clenching.

Effect of unpleasant loud noise on hippocampal activities during picture encoding: an fMRI study.

The functional link between the amygdala and hippocampus in humans has not been well documented. We examined the effect of unpleasant loud noise on hippocampal and amygdaloid activities during picture encoding by means of fMRI, and on the correct response in humans. The noise reduced activity in the hippocampus during picture encoding, decreased the correct response and increased the activity of the amygdala. A path diagram using structural equation modeling suggested that hippocampus activity might be depressed by high amygdala activity. Therefore, noise should diminish memory by reducing hippocampal activity, which might be depressed by high amygdala activity.

Gamma knife surgery of the pituitary: new treatment for thalamic pain syndrome.

OBJECT: Although reports in the literature indicate that thalamic pain syndrome can be controlled with chemical hypophysectomy, this procedure is associated with transient diabetes insipidus. It was considered reasonable to attempt gamma knife surgery (GKS) to the pituitary gland to control thalamic pain. METHODS: Inclusion criteria in this study were poststroke thalamic pain, failure of all other treatments, intolerance to general anesthetic, and the main complaint of pain and not numbness. Seventeen patients met these criteria and were treated with GKS to the pituitary. The target was the pituitary gland together with the border between the pituitary stalk and the gland. The maximum dose was 140 to 180 Gy. All patients were followed for more than 3 months. CONCLUSIONS: An initial significant pain reduction was observed in 13 (76.5%) of 17 patients. Some patients experienced pain reduction within 48 hours of treatment. Persistent pain relief for more than 1 year was observed in five (38.5%) of 13 patients. Rapid recurrence of pain in fewer than 3 months was observed in four (30.8%) of 13 patients. The only complication was transient diabetes insipidus in one patient. It would seem that GKS of the pituitary might have a role to play in thalamic pain arising after a stroke.

The effect of gamma knife irradiation on functions of striatum in rats.

OBJECT: An animal model has been developed to study the effect of gamma knife surgery(GKS) on cerebral function. METHODS: A rat was fixed in a newly developed Régis-Valliccioni frame that enables the target region to be planned directly on the magnetic resonance images. The left striatum was irradiated with 150 Gy via a 4-mm collimator of the Leksell gamma knife. Apomorphine (dopamine agonist) was administered to elicit a circling behavior (apomorphine test) after the GKS so as to examine the time course of the changes in dopaminergic functions of irradiated striatum. After a series of behavioral analyses, irradiated brains were subjected to histological examination. Necrosis was observed in the irradiated area surrounded by hemorrhage and gliosis. The distance between the histologically estimated and planned centers of the irradiation areas was 1.0 +/- 0.5 mm. The extent of the distance was due to errors along dorsoventral axis. The distribution of the irradiation areas influenced the activity and the circling behaviors in apomorphine test, which was suggestive of involvement of the nigrostriatal pathway. CONCLUSIONS: Targeting by using the Régis-Valliccioni frame was very accurate compared with targeting with coordinates based on brain maps used hitherto. Although targeting improved the accuracy, further effort will still be necessary to reduce errors along dorsoventral axis. The apomorphine test indicated a reduced dopaminergic function of the irradiated area including striatum, which accompanied histological changes after a high dose of irradiation (150 Gy).

Heat-induced secondary structure and conformation change of bovine serum albumin investigated by Fourier transform infrared spectroscopy.

Fourier transform infrared (FT-IR) spectra were measured for an aqueous solution (pD = 5.40) of defatted monomer bovine serum albumin (BSA) over a temperature range of 25-90 degrees C to investigate temperature-induced secondary structure and conformation changes. The curve fitting method combined with the Fourier self-deconvolution technique allowed us to explore details of the secondary structure and conformation changes in defatted BSA. Particularly striking in the FT-IR spectra was an observation of the formation of an irreversible intermolecular beta-sheet of BSA on heating above 70 degrees C. A band at 1630 cm(-1) in the spectra was assigned to short-segment chains connecting alpha-helical segments. The transition temperature for the short-segment chains connecting alpha-helical segments is lower by 17-18 degrees C, when compared to those of the alpha-helix, turn, and intermolecular beta-sheet structures of BSA, suggesting that the alpha-helix and turn structures of BSA are cooperatively denatured on heating. Moreover, the results give an important feature in heat-induced denaturation of BSA that the conformation changes occur twice around both 57 and 75 degrees C. The appearance of two peaks is interpreted by the collapse of the N-terminal BSA domain due to the crevice in the vicinity between domains I and II at low-temperature transition and by the change in cooperative unit composed of the other two BSA domains at high-temperature transition.