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Biomedical subjects

H Tsuru

Publications and source records attributed to H Tsuru.

At least 55 records · Page 3Linked to original sources
PubMed1990

Antifungal drugs affect adherence of Candida albicans to acrylic surfaces by changing the zeta-potential of fungal cells.

The effect of sub-inhibitory concentrations of antifungal drugs on the adherence of Candida albicans to acrylic surfaces was investigated. Among five antifungals tested, azalomycin F and aculeacin A significantly enhanced the adherence. The zeta-potential of fungal cells was affected by antifungal drugs, whereas no significant change in cell surface hydrophobicity was observed. The relationship obtained between the change in the adherence and that in zeta-potential suggests that the enhanced adherence was caused by decreased electric repulsive forces.

Acrylates↗
PubMed1990

Two types of jaw-muscle spindle afferents in the cat as demonstrated by intra-axonal staining with HRP.

Intra-axonal records and horseradish peroxidase (HRP) injection techniques were employed to define the response properties of the jaw-closing muscle spindle afferents in the trigeminal mesencephalic nucleus (Vmes) and their morphological characteristics. The axonal trajectories of 9 spindle afferents from the masseter and 4 afferents from the temporalis were recovered for detailed analyses. Of 13 afferents, 6 cell bodies were stained and they were located at the rostrocaudal mid-levels of the Vmes. The central courses of the stem fibers were organized in a similar manner to the Vmes periodontal afferent nerves with the exception that peripheral (P) fibers of all spindle afferents passed through the trigeminal motor tract and root. On the basis of collateral terminal arborizations, the Vmes spindle afferents could be classified into two types: type I (n = 6) and type II (n = 7). Type I afferents sent their collaterals into the trigeminal motor nucleus (Vmo), intertrigeminal region (Vint) and juxtatrigeminal region (Vjux), but collaterals from the two neurons also projected to Vmes and the nucleus oralis (Vo). The collaterals from type II afferents formed their terminal arbors in the supratrigeminal nucleus (Vsup) in addition to the Vmo, Vint and Vjux, but collaterals from one neuron also projected to the Vo. In type I afferents, terminal arbors encompassed the whole Vmo including jaw-closing motoneurons. In contrast, boutons from type II afferents were restricted to a few small portions within the Vmo in proximity to its lateral and dorsal boundaries. The diameters of the united (U), central (C) and peripheral (P), fibers were larger in type I than type II afferents; those of the U fibers were statistically significant. Any differences between the two distinct types were not found in the response pattern to the sustained jaw opening. These results suggest that the difference of primary and secondary muscle-spindle afferent nerves is reflected in a distinctive morphology in the terminal arborizations and in the diameters of united fibers rather than the response patterns in deeply anesthetized cats.

Action Potentials↗
PubMed1990

Prevention of acquired immunodeficiency syndrome and hepatitis B. Part III: Disinfection of hydrophilic silicone rubber impression materials.

The effect of glutaraldehyde solution, an effective disinfectant for viruses, on the dimensional stability of hydrophilic silicone rubber impression materials was evaluated in this study. Disinfection with 2% glutaraldehyde solution showed a slight expanding effect on the dimensional stability of the hydrophilic silicone rubber impression materials (less than 0.03%). It was revealed that glutaraldehyde can be used for the disinfection of hydrophilic silicone rubber impression materials. Attention should be paid, however, to the conditions for investment or casting to eliminate the expanding effect of this disinfecting procedure.

Acquired Immunodeficiency Syndrome↗
PubMed1990

Initial interface between submerged hydroxyapatite-coated titanium alloy implant and mandibular bone after nontapping and tapping insertions in monkeys.

To clarify whether direct bone interface of submerged plasma-sprayed hydroxyapatite-coated implants could be achieved by nontapping insertion, histologic and histometric studies were made on the structure of the interface between the implant and the mandible in two monkeys. All hydroxyapatite-coated implants, whether by nontapping or tapping insertions, were healed with direct bone apposition. No histologic and histometric difference of interface structure was observed between nontapping and tapping insertions.

Alloys↗
PubMed1990

Prevention of acquired immunodeficiency syndrome and hepatitis B. Part IV: The effect of impression material on glutaraldehyde solution.

Immersion of dental impressions in 2% glutaraldehyde has been shown to be an effective disinfection procedure for viral contamination. This study compared the effect of immersing impression materials on the concentrations of glutaraldehyde. Contamination with saliva slightly affected the concentration of glutaraldehyde. Irreversible hydrocolloid impression material markedly decreased the concentration of glutaraldehyde, whereas the immersion of silicone rubber impression material only slightly affected the concentration of glutaraldehyde. Attention should be paid to the concentration of glutaraldehyde solution when irreversible hydrocolloid impression material is immersed in the disinfectant.

Acquired Immunodeficiency Syndrome↗
PubMed1990

Changes in retention of various telescope crown assemblies over long-term use.

An investigation was done on the effect of crown height, angle (one-half taper) and number of removals on the retention of telescope crowns. Assemblies of inner and outer crowns were constructed on master dies. Crown heights of 4 mm, 5 mm, and 6 mm were used. Cone angles of 0, 2, 4, and 6 degrees were used for each of the three heights. The inner crowns were fixed to the dies with an adhesive agent. the outer crowns were set over them and placed in a clamp. Separation forces were tested with an Instron machine (Instron Corp., Canton, Mass.). They were measured initially and after numerous 100 insertion/separation cycles up to 1000 cycles and numerous 500 insertion/separation cycles up to 10,000 cycles. The results demonstrated that the cone angle of the inner crown was more important than its height for maximum retention. Retention is rapidly lost after the cone angle exceeds 2 degrees. It was also shown that an accessory device is necessary to maintain retention capabilities after long-term use.

Analysis of Variance↗
PubMed1990

Finite element analysis of the relationship between clasp dimensions and flexibility.

A parameter study with use of the finite element method was conducted for examination of the relationships between the shape parameters of a clasp (width and thickness at the base and tip of the clasp) and its displacement or stress. By synthesis of these relationships, a simple formula defining the clasp tip displacement in terms of clasp dimensions ("displacement formula") was obtained. A stiffness parameter "Fd" (the load producing a 1-mm displacement of the clasp tip) was proposed, and a formula defining Fd in terms of shape parameters was derived from the displacement formula. Fd would be a practical parameter for the definition of clasp retention, and the present formulae appear to be useful tools for investigation of the retention of removable partial dentures.

Chromium Alloys↗
PubMed1990

[Tooth tapping frequency of young and elderly subjects].

Tooth tapping frequency was measured in young (21-29 years) and elderly (61-67 years) subjects. They were asked to continue the maximal frequent tapping during 1 min., and their mandibular movement were measured with a Mandibular Kinesiograph. The results are as follows: 1. Each phase of closing, occluding, opening and cycle was prolonged at the terminal of the 1 min. tapping. That is, tapping frequency decreased. Young subjects had 4.6 Hz tapping frequency and 2.7 Hz for elderly subjects. 2. Although the opening phase per cycle and the closing were not changed in spite of the tapping continuity, the occluding one increased at the terminal of the 1 min. tapping. 3. No difference existed between the young subjects and elderly in the maximal velocity of the mandibular movement at the opening and closing. Opening velocity was larger than closing velocity at the young subjects.

Adult↗
PubMed1990

[A study on mandibular incisal point movement of TM disorder patients].

In order to establish diagnostic and treatment system for temporomandibular (TM) disorder patients, data were collected on mandibular border and tapping movements at incisive point and compared with those from the subjects without any TM disorders. Significant differences on the ratio of left and right sides of maximum lateral deviation, maximum opening amount and length of pathway of lateral border movement were clearly obtained, the values of maximum speed and acceleration of closing phase in tapping movement obtained from TM disorder patients were also different significantly from those in the control subjects. These findings suggests that those measured indices in this study would be useful for diagnosis of TM disorders.

Dental Occlusion↗
PubMed1990

[A study of the effectiveness of denture cleanser on human breath].

The purpose of this study is to measure the human breathes of denture wearers by using breath sensor, and to evaluate the influence of denture cleansing. The following results were obtained. 1. There is a possibility that the human breathes of full denture wearers may originate from their dentures. 2. There is a possibility that the cleansed dentures may cover the smell of the patient's oral mucosa itself and may reduce the apparent human breathes. Anyhow, the human breathes of denture wearers reduce significantly by using the denture cleanser.

Breath Tests↗
PubMed1990

Relationship between balancing-side occlusal contact patterns and temporomandibular joint sounds in humans: proposition of the concept of balancing-side protection.

Balancing-side contact patterns and temporomandibular joint sounds were evaluated in 430 young adults. Correlational analysis revealed that there was a highly significant positive correlation between the absence of balancing-side contacts and an increasing prevalence of joint sounds with age (r = 0.975). These data support the hypothesis that certain types of balancing-side contacts may be protective of the temporomandibular joint.

Adult↗
PubMed1990

[Computed tomography of obturator foramen hernia].

A 89 year-old female was admitted with the complaint of right hypochondralgia. And also she complained of right thigh pain after admission. On hospital day 4, she underwent CT examination in order to evaluate right thigh with severe pain. The preoperative diagnosis of obturator foramen hernia was performed.

Aged↗
PubMed1989

Somatotopic organization of tooth pulp primary afferent neurons in the cat.

Transganglionic transport of horseradish peroxidase-wheat germ agglutinin conjugate (HRP-WGA) was used to study the somatotopic organization of pulpal afferent neurons innervating the different types of teeth in the trigeminal ganglion and trigeminal sensory nuclear complex (TSNC). In separate animals, the upper first 3 incisors (UI1-3), canine (UC), second premolar (UP2) and third premolar (UP3), and the lower first three incisors (LI1-3), canine (LC), first premolar (LP1), second premolar (LP2) and molar (LM) were traced in this experiment. Cell bodies innervating posterior teeth were found with greater frequency in dorsal maxillary ganglion regions, while somata supplying more anterior teeth were predominant ventrally. In contrast, cell bodies innervating the lower teeth were not arranged in a somatotopic fashion in the mandibular subdivision. Each pulpal afferent from lower and upper teeth projected to the subnucleus dorsalis (Vpd) of the pars principalis, the rostrodorsomedial (Vo.r) and dorsomedial parts (Vo.dm) of the pars oralis (Vo), the medial regions of the pars interpolaris (Vi), and laminae I, II, and V of the medullary dorsal horn, and terminal fields between the upper and lower teeth were separated in each subdivision. Pulpal projections from both the upper and lower teeth to each subdivision were organized in a somatotopic manner, while an extensive overlap in projections was noted between the adjoining teeth. In the Vpd, the upper and lower teeth were represented dorsoventrally, and projections from the anterior to posterior teeth in the upper jaw were arranged in both rostrocaudal and ventrodorsal sequences whereas those in the lower jaw were organized caudarostrally and lateromedially. In the Vo.r and Vo.dm, the upper and lower teeth were represented in a mediolateral sequence and projections from the anterior to posterior teeth were organized in a ventrolateral to dorsomedial sequence. In the Vi, pulpal projections were organized in a topographic fashion similar to that observed in the Vo.r and Vo.dm. In the medullary dorsal horn, the upper and lower teeth were represented in laminae I, II and V in a lateromedial sequence. Their projections to laminae I and V were topographically organized in a mediolateral and rostrocaudal sequence.(ABSTRACT TRUNCATED AT 400 WORDS)

Afferent Pathways↗
PubMed1989

A short-term evaluation of the effectiveness of stabilization-type occlusal splint therapy for specific symptoms of temporomandibular joint dysfunction syndrome.

To clarify the short-term effectiveness of stabilization-type occlusal splint therapy, a specific symptom approach was used toward 30 temporomandibular joint dysfunction patients with more than two major symptoms (temporomandibular joint and/or masticatory muscle pain, temporomandibular joint sounds, and limitation of mandibular movement). Eighty-seven percent of the patients with pain responded with this therapy and more than 50% had complete relief of pain 4 weeks after insertion of the splint. Temporomandibular joint sounds and limitation of mandibular movement responded more slowly than pain. These results suggest that the stabilization-type occlusal splint should be selected as a first choice among several therapies and that temporomandibular joint pain is particularly susceptible to this therapy.

Acrylic Resins↗
PubMed1989

Ultrastructure of the peri-implant junctional epithelium on single-crystal sapphire endosseous dental implant loaded with functional stress.

To elucidate the ultrastructure of peri-implant junctional epithelium (IJE) on single-crystal sapphire dental implants connected to the adjacent teeth by a metal superstructure, the peri-implant gingivae of ten monkeys were examined using a transmission electron microscope (TEM) at 3, 6 and 12 months after implant insertion. At the time of examination, the ultrastructural features of the IJE were almost identical to those of junctional epithelium (JE) attached to natural teeth, i.e. developed Golgi complexes, rough-surfaced endoplasmic reticulum, numerous free ribosomes and mitochondria. The innermost cells of IJE were attached to the implant surface by means of basal lamina-like structures (500-1000 A in thickness) and hemidesmosomes, but lacked a dental cuticle as seen on teeth. Such epithelial attachment of the IJE was often indistinct or absent at the apical portion of the IJE which terminated at the level of alveolar crest. A continuous basal lamina-like structure was also present along basal cells at the interface between the IJE and gingival connective tissue except at its apical portion.

Aluminum↗