Reliability of clinical parameters for predicting the outcome of oral malodor treatment

We conducted the present study to determine which clinical parameters for diagnosing halitosis are most reliable in the development of an accurate prognosis for oral malodor treatment. Clinical evaluation included a questionnaire, oral examination and volatile sulfur compounds (VSC) measurement, and organoleptic test (OLT) at baseline. Ninety-two patients classified with oral pathologic halitosis were treated in a similar manner. Improved treatment outcome was defined as < 0.25 ppm of total VSC, < or = 2 OLT score, and < 30 on the "sad feeling" scale as subjective stress level by oral malodor 6 months after baseline. Thirty-four patients demonstrated improvement due to the treatment. In a multiple logistic model, pocket depth, OLT score, intra-oral discomfort, and self-perception of oral malodor at baseline displayed significant association with "not improved outcome". These results suggest that malodor- and periodontal-disease-related parameters and self-estimation of malodor at baseline are effective for prediction of outcome.     

Selective electrochemical reduction of CO2 to ethylene at a three-phase interface on copper(I) halide-confined Cu-mesh electrodes in acidic solutions of potassium halides

In the electrochemical reduction of CO₂ on a Cu foil electrode in a neutral solution, the electrode suffers a decline in its catalytic activity for the reduction of CO₂ to hydrocarbons. This is caused by the deposition of poisonous compounds such as graphitic carbon. To settle this problem, we have developed an electrolysis system in which CO₂ is reduced at the three-phase (gas|liquid|solid) interface on a Cu-mesh electrode. In the present study, a Cu-mesh electrode is modified beforehand by copper(I) halides, and CO₂ is reduced at a constant potential with these modified electrodes in an acidic solution of potassium halide. The Faradaic efficiency for C₂H₄ is considerably increased and reversely that for H₂ is decreased by confining a copper(I) halide. In the case of CuBr, the conversion of CO₂ to C₂H₄ and the hydrogen evolution are observed with Faradaic efficiencies of about 80% and 9%, respectively. Such a contribution of copper(I) halide to the CO₂ reduction is related to its reversible combination with CO and C₂H₄. At the three-phase interface, CO₂(g) is first reduced to CO(g). This gas is ready to adsorb to copper(I) halide with its π-bond perpendicular to the surface, and the CO is subjected to electron injection from the electrode to be reduced to the methylene radical. The coupling of methylene radicals results in the formation of C₂H₄ and this product is stabilized by adsorbing to copper(I) halide with its π-bond parallel to the surface.     

A new porcelain repair system with a silane coupler, ferric chloride, and adhesive opaque resin

A new porcelain repair system was developed which uses a two-liquid primer, self-cured opaque resin, and light-cured composite. The primer consisted of two liquids. One component was 4% 3-trimethoxysilylpropyl methacrylate in methyl methacrylate, and the other component was 0.5% ferric chloride in ethanol. A self-curing opaque resin, 4-META/MMA-TBB opaque resin, was used as an adhesive to bind the porcelain and the composite. Adhesive opaque resin was applied on the roughened and primed porcelain. Light-cured composite was placed over the 4-META opaque layer. A shear test was performed for investigation of the strength and durability of the bonding. The result was that for all specimens after 20,000 thermocycles, fracture or crack propagation during the shear test occurred in the porcelain, rather than in the bond. This system may be used to repair fractured porcelain facings without removal of prostheses.     

Ultrasound observations of tongue motor behavior

In this investigation of motor skills of the tongue and age-related changes in motor behavior, upward and downward tongue movements with the teeth in centric occlusion and regulated by a metronome were recorded. The recordings were made by use of ultrasound diagnostic equipment with a 5 MHz electronic convex section scanning probe and a physiologic signal unit connected to a heart sound microphone in a group of young subjects and a group of older subjects. The results were as follows. (1) The system provided a useful method to evaluate motor skills of the tongue with sound signals showing clear images of the tongue surface and its movements. (2) The rhythm of tongue movements in older persons varied more than in younger persons. (3) The velocity in the upward and downward movements decreased and were statistically significant (p less than 0.01) in the older group. (4) The time lag between the sound signal and the start of touching the palate and floor of the mouth was longer (p less than 0.01) and the variations were greater in the older group. (5) The study showed age-related changes in motor behavior of the tongue.     

Effect of serotonin (5-HT) on trigeminal rhythmic activities generated in in vitro brainstem block preparations

We used rat isolated brainstem block preparations to analyze the functional roles of serotonin receptors in the generation of trigeminal rhythmic activities. We previously reported that trigeminal rhythmic activities could be induced by some pharmacological applications in an isolated brainstem preparation with a rostral boundary at the border between the inferior and superior colliculus, and a caudal border at the level of the rostral facial nucleus. However, the same stimulation did not induce trigeminal rhythmic activities in a whole brainstem block preparation with the same rostral boundary and a caudal border at the obex level. In the present study, both the 5-HT(1A) phthalimido-butyl-piperazine, and the 5-HT(2C) agonist, 1-2,5-dimethoxy-4-iodophenyl-2-aminopropane, combined with N-methyl-D,L-aspartate and bicuculline, elicited trigeminal rhythmic activities in a whole brainstem block preparation. Our results suggest that serotonin has both facilitation and inhibition effects on the generation of trigeminal rhythmic activities in an isolated brainstem block preparation in vitro.     

Distribution of movement-related cortical potential upon jaw-biting in humans

We examined the cerebral location of the readiness potential (hereinafter referred to as "RP") upon activation of the masseter muscle by voluntary and unilateral jaw-biting movement. Four normal adults served as subjects. Five scalp electrodes were placed according to the international 10-20 method at CZ, C3, C4, T3 and T4. In addition, in one of the subjects, RPs were recorded by 12 scalp electrodes in order to study changes occurring in the distribution of RPs with time. The maximum amplitude of the RP was located at T4 in the temporal area, which was involved in the biting movement as a negative slow potential occurring 1.4-0.8 s before the beginning of the discharge to the masseter muscle. The maximum amplitude of the RP on the contralateral side was located at T3. This meant that the amplitude of the RP tended to be higher on the same side as the biting movement than on the contralateral side in all subjects. From scalp topography, the maximum amplitude of the RP was shown to be confined to T4, and was especially marked immediately before the beginning of discharge to the masseter muscle. From these results it is thought that in the case of voluntary biting movement, the RP reflects activities of the pyramidal cells in the masticatory area of the cortex, and that strong descending impulses from both sides then reach the masseter muscles.