A Study of Criteria for Arrangement of Teeth and Shape of Posterior Residual Ridges by Moiré Topography

The aim of this work was to clarify by Moiré topography the morphological criteria for arrangement of teeth. The alveolar crest line and alveolar crest zone were defined by Moiré topography photographs from 139 upper edentulous stone casts and 20 upper and lower casts which were mounted to articulators. From the results the overlap area between upper and lower alveolar crest zones was classified into 6 types. It is suggested that the overlap areas and the angle between interalveolar lines are very useful as criteria for posterior tooth arrangement in clinical procedures

A Clinical Examination and Electromyographic Evaluation in Edentulous Patient with MPD Syndrome

It is not easy to establish the proper maxillo-mandibular relations and occlusion in order to construct complete dentures for edentulous patients who have lost all their natural teeth and surrounding structures. For this reason, many practitioners have studied the accurate procedures for jaw measurement. However, if edentulous patients have an improper measurement of occlusal vertical dimension and/or maxillo-mandibular relations in prosthetic treatment, they often complain of functional disorder of the masticatory system and the interaction between the muscles, the joints and occlusion. In these patients the functional demand exceeds the adaptive capacity of the neuromusculature. As a result, these patients exhibit muscle pain, deviation of the mandible on opening, joint noises, limited opening of the jaws, or other symptoms associated with the syndrome. In complete denture wearers with myofascial pain-dysfunction (MPD) syndrome, symptoms disappeared after improvement of the occlusal vertical dimension with the lower treatment denture. There were clear differences between before and after prosthetic treatment with electromyographic (EMG) activity of the masseter muscles

The Morphological Study of Maxillary Edentulous Ridges and Palates by Moiré Topography

It is important to study the morphology of upper and lower edentulous ridges and palates on the basis of complete denture construction. We have conducted a mathematical method to classify the cross-section of the palatal vault and/or the alveolar crest line form with Fourier analysis without using methods of inspection which have already been discussed. As a result, the cross-section of palatal vaults can be divided into Ovoid, Square and V-shaped types, and alveolar crest lines can be divided into 4 types. This method appears to be an objective one avoiding the researcher\u27s subjective point of view

Dimensional Accuracy of Acrylic Resin Denture Bases : Literature Review

The more contact there is between the denture base and the cast, the better the fit, resulting in a close adaptation of the denture surface to the oral mucosa and a more retentive denture. Many prosthodontists, however, feel that compression-molded dentures processed with acrylic resins become ill fitting in the mouth because they warp severely during processing and while in service. One of the reasons for this problem is shrinkage of the acrylic resin due to polymerization. This article reviews the studies on accuracy of denture bases using various activation methods for polymerization of acrylic resin

Heat acclimatization blunts copeptin responses to hypertonicity from dehydrating exercise in humans.

Acclimatization favors greater extracellular tonicity from lower sweat sodium, yet hyperosmolality may impair thermoregulation during heat stress. Enhanced secretion or action of vasopressin could mitigate this through increased free water retention. Aims were to determine responses of the vasopressin surrogate copeptin to dehydrating exercise and investigate its relationships with tonicity during short and long-term acclimatization. Twenty-three participants completed a structured exercise programme following arrival from a temperate to a hot climate. A Heat Tolerance Test (HTT) was conducted on Day-2, 6, 9 and 23, consisting of 60-min block-stepping at 50% VO2 peak, with no fluid intake. Resting sweat [Na+ ] was measured by iontophoresis. Changes in body mass (sweat loss), core temperature, heart rate, osmolality (serum and urine) and copeptin and aldosterone (plasma) were measured with each Test. From Day 2 to Day 23, sweat [Na+ ] decreased significantly (adjusted P < 0.05) and core temperature and heart rate fell. Over the same interval, HTT-associated excursions were increased for serum osmolality (5 [-1, 9] vs. 9 [5, 12] mosm·kg-1 ), did not differ for copeptin (9.6 [6.0, 15.0] vs. 7.9 [4.3, 14.7] pmol·L-1 ) and were reduced for aldosterone (602 [415, 946] vs. 347 [263, 537] pmol·L-1 ). Urine osmolality was unchanging and related consistently to copeptin at end-exercise, whereas the association between copeptin and serum osmolality was right-shifted (P = 0.0109) with acclimatization. Unchanging urine:serum osmolality argued against increased renal action of vasopressin. In conclusion, where exercise in the heat is performed without fluid replacement, heat acclimatization does not appear to enhance AVP-mediated free water retention in humans

市販軟質裏装材10種類の物理・機械的性質と臨床的観察

Ten commercial soft lining materials were selected to be representative of the types currently available including plasticised acrylic, silicone and fluorine-containing materials. These have been investigated in terms of their tensile, tear and hardness properties. With the exception of tear strength, where silicone materials had the lowest values, there appeared to be no correlation between material type and property. All but two of the materials had hardness values in the range of 30.3 to 43.7. The general conclusion was that the materials selected showed a large variability in the properties investigated. Regarding clinical aspects of some soft lining materials used for acrylic resin denture bases, it was appeared that colour change and deterioration occurred

新しいBis-GMA類似体を基調としたコンポジットレジンペースト性質と特徴

The relationship between filler type, filler content, and matrix resin composition and viscosity, and the flow characteristics of composite formulations were investigated. The structures of three newly synthesized monomers, i.e., 3F Bis-GMA, 6F Bis-GMA (Bis-GMA analogues) and IP AGDM (based on phthalic acid) were analyzed to determine their viscosity and polymerization shrinkage. Viscosities were determined with a cone and plate viscometer and shrinkages were determined gravimetrically. All three experimental monomers required less dilution than Bis-GMA, and they exhibited remarkable reductions in polymerization shrinkage relative to Bis-GMA. Bis-GMA and 4 experimental Bis-GMA analogues were also evaluated. For each monomer-filler combination, increasing filler contents resulted in monotonic plasticities. The maximum filler contents appeared to be an attribute of the particular filler rather than a matrix resin characteristic. Plasticity differences existed, unexpectedly, even at constant filler contents and matrix viscosities. Evidence was found that the plasticity varied with the base monomer composition and the amount of TEGDMA present

国際規格ISO 10139-1による市販ティッシュコンディショナーの比較検討

The aim of this study was to analyze the composition of eight commercial tissue conditioners, assess each material using the International Standard (ISO) 10139-1 and relate differences in properties to composition. A visible light spectrophotometer (IR-460: Shimadzu, Kyoto, Japan) was used to analyze the principal components of both liquids and polymer powders. A High Pressure Liquid Chromatograph (HPLC: Shimadzu, Kyoto, Japan) was used to measure the principal ingredients. A gas chromatograph (GC-15A: Shimadzu, Kyoto, Japan) was used to measure the alcohol concentration. Consistency and penetration tests were carried out as detailed in the ISO 10139-1. The penetration test measurements were also made at 2, 3 and 4 weeks. All materials satisfied the standard in the consistency test and in the penetration test after one week. However, three materials failed to satisfy the standard in the penetration test after two hours. In all materials the powder was found to be poly (ethyl methacrylate), while plasticizers and ethanol content varied. Two materials contained other components thought to be antibiotic or antibacterial agents. There appeared to be a correlation between the ethanol content and the consistency results

Endogenous androgens diminish food intake and activation of orexin A neurons in response to reduced glucose availability in male rats

Sex steroids modify feeding behavior and body weight regulation, and androgen reportedly augments food intake and body weight gain. To elucidate the role of endogenous androgens in the feeding regulation induced by reduced glucose availability, we examined the effect of gonadectomy (orchiectomy) on food intake and orexin A neuron’s activity in the lateral hypothalamic/perifornical area (LH/PFA) in response to reduced glucose availability (glucoprivation) induced by 2-deoxy-d-glucose (2DG) administration in male rats. Rats (7W) were bilaterally orchiectomized (ORX group) or sham operated (Sham group). Seventeen days after the surgery, food intake response to 2DG (400 mg/kg, i.v.) was measured for 4 h after the infusion. The same experiment was performed for the immunohistochemical examination of c-Fos-expressing orexin A neurons in the LH/PFA and c-Fos expression in the arcuate nucleus (Arc). Food intake induced by glucoprivation was greater in the ORX group than the Sham group, and the glucoprivation-induced food intake was inversely correlated with plasma testosterone concentration. Glucoprivation stimulated c-Fos expression of the orexin A neurons at the LH/PFA and c-Fos expression in the dorsomedial Arc. The number and percentage of c-Fos-expressing orexin A neurons in the LH/PFA and c-Fos expression in the dorsomedial Arc were significantly higher in the ORX group than the Sham group. This indicates that endogenous androgen, possibly testosterone, diminishes the food intake induced by reduced glucose availability, possibly via the attenuated activity of orexin A neuron in the LH/PFA and neurons in the dorsomedial Arc