This paper described the incidence of inferior alveolar nerve paralysis following surgical removal of impacted third molars. The investigated cases were 789 patients with 1, 299 teeth that were surgically extracted. Eight (0.6%) patients had the inferior alveolar nerve paralysis and one (0.08%) had lingual nerve paralysis. As for the patients with inferior alveolar nerve paralysis, the incidence was 0.4% in those aged 20 to 29 years, 0.6% in those aged 30 to 39 years, and 3.5% in those aged over 40 years. This study showed that the incidence of inferior alveolar nerve paralysis occurred more frequently in older age cases and in the cases in which the root splitting or the removing the surrounding bone was needed.
Latin anatomical names ofForaminaandCanalesin skeleton were analyzed and compared with Japanese anatomical names for better understanding of the structures of the human body and for possible revision in the future. The conclusions were as follows: 1. In general, short tunnels were calledForamina (singular : Foramen), and long tunnels Canales (singular : Canalis) . 2. One end ofCanaliswas sometimes calledForamen. In this case, CanalisandForamenwere usually modified by the same words. 3. Each name ofForaminacontained the word which means form, state, absolute size, region of existence, one of the contents or function ofForamina. 4. Each name ofCanalescontained the word which means region of existence, one of the contents or function ofCanales. 5. Some names ofForaminaandCanalesthat were supposed to mean the region of existence meant one of the contents of the structures. 6. As for Latin anatomical names, the relation between words were relatively clear by the proper use of noun, adjective, nominative, and genitive. 7. Since different Chinese characters were sometimes pronouced similarly in Japanese anatomical names, different structures might be confused. 8. It seemed that some Japanese anatomical names needed partial correction.
The purpose of this study was to investigate the influence of orthognathic surgery on the speech quality of patients with skeletal mandibular protrusion. Samples of speech sounds were collected from 10 patients (8 females, 2 males) before and after surgical operation. Acoustic analysis, based on the linear predictive coding (LPC), was applied to analyze the lowest two local spectral peaks (P1, P2) on the vowels. Psychoacoustic examination was also carried out by 24 examiners using the paired comparison in naturalness of five different words. The results were as follows: 1) The widened vowel trajectory after orthognathic surgery seemed to be related to improvement of articulatory function. 2) The naturalness of speech in psychoacoustic examination has been improved in most patients after orthognathic surgery. 3) Patients who have improved naturalness of speech showed a tendency of having a widened vowel trajectory.
The purpose of this study was to investigate the process of micrognathic development in mouse fetus induced by Sulfadimethoxine (SDM) . SDM of 3, 000mg/kg was administered orally to pregnant ICR mice on days 8, 9, 10, 11, 12, and 13 of gestation. The fetuses were removed on day 15 to analyze the incidence of micrognathia. The incidence of micrognathia was the highest in the treated group on day 10. The fetuses, SDM-treated on day 10, were sacrificed on days 11, 12, 13, 14, 15, and 18 and prepared for histological and morphological analyses. Histomorphological analyses were performed by lateral and horizontal graphic reconstruction using serial frontal sections. It was also performed by clearing and alcian blue-alizarin red double staining. In the treated group, bilateral sigmoid buckling and shortening of Meckel's cartilage became evident after day 14, however, the nasal septal and capsule cartilage were less affected. It was concluded that remarkable hypoplastic and malformed Meckel's cartilage, caused by the administration of SDM, induced mandibular dysmorphogenesis.
Apoptosis Signal-regulating Kinase (ASK) 1 was identified that activated two different subgroup of MAP kinase kinase (MAPKK), SEK1 (or MKK4), and MKK3/MAPKK6 (or MKK6), which in turn activated stress-activated protein kinase (SAPK, also known as JNK : c-Jun amino-terminal kinase) and p38 subgroup of MAP kinases, respectively. It was suggested that ASK1 contributed to cytokine-induced apoptosis in some cell lines. In this report, for further investigation about roles of ASK1 in mammal, initial characterization of mouse ASK1 was done. The mouse cDNA encoding ASK1 was isolated from the mouse kidney cDNA library and the overall amino acid sequence similarity between the mouse and the human ASK1 was 91.9%. A database search revealed that the kinase domain of ASK1 is evolutionally well -concervedover species among nematode, fly, mouse, and human. Northern blot analysis identified a 6-kb transcript of ASK1 which is expressed in the various mouse adult tissues. Immunohistochemical analysis of mouse embryos (17 days post coitum) revealed a localized expression of ASK1 in developing skin, cartilage, and bone, suggesting a possible role of ASK1 in tissue development during embryogenesis as well as cytokine-induced apoptosis.
Host derived blood protein adsorption is much more rapid than the migration of cells to foreign surfaces, so the effect of host proteins in blood on blood cells and bone marrow cells was investigated by means ofin vitroculturing of blood and bone marrow cells on titanium. A material preincubated with plasma induced high nonspecific esterase (NSE) activity and polymor-phonuclear neutrophil (PMN) elastase activity, but neither a serum- nor albumincoated material had the same effect as the plasmacoated material. Therefore, attention was paid to fibrinogen. On titanium coated with fibrinogen increases in not only NSE activity and PMN elastase activity in blood and bone marrow, but also tartrate-resistant acid phosphatase (TRACP) activity were observed in bone marrow cultures. A decrease in alkaline phosphatase (ALP) activity was also observed in the cultures. These changes of bone marrow cultures were reversed by the addition of recombinant human bone morphogenetic protein-2 to the cultures. These results suggested that bleeding around titanium affects the function of macrophages or neutrophils due to the effect of fibrinogen. Furthermore, it was suggested that this factor may affect the functions of osteoblasts and osteoclasts around a titanium implant with the inevitable side effects of implantation in bone tissue: bleeding and clotting.
Modulation of the tibialis anterior (T.A.) H reflex and the reciprocal Ia inhibition from the ankle flexor to the extensor were studied during voluntary teeth-clenching in 7 healthy adult volunteers to investigate the correlation between the oral motor activity and the somatic motor function. The TA. H reflex was significantly facilitated during voluntary teeth-clenching, and the amount of this facilitation increased with the level of masseter EMG activity. Furthermore, the reciprocal Ia inhibition of the soleus H reflex, induced by stimulation of the common peroneal nerve at a subthreshold intensity for evoking the T.A.M wave, was significantly depressed during voluntary teeth-clenching. It was concluded that 1) the TA. H reflex is facilitated during voluntary teeth-clenching, 2) there is a positive correlation between the amount of facilitation of the TA. H reflex and the level of teeth-clenching force, and 3) the reciprocal Ia inhibition of the crural muscle is reduced during voluntary teeth- clenching. It was suggested that teethclenching contributes to stability of body stance by increasing the stiffness of the ankle joint.
The purpose of this study was to investigate the changes of the activity of the sternocleidomastoid (SCM) muscles during sustained voluntary clenching. Ten healthy male subjects without any occlusal functional problems were asked to clench as long as possible in the intercuspal position while keeping the electromyographic activity of the masseter muscle at the 50% maximum voluntary contraction. Frequency analysis was carried out by computer using a fast Fourier transform algorithm to obtain the power spectrum of the SCM muscle during the fatiguing process and the recovery process. The results were as follows: 1. Sustained activities of the SCM muscles were observed during sustained voluntary clenching. 2. The power spectra of the SCM muscles significantly shifted to a lower frequency as time elapsed. 3. The power spectra of the SCM muscles obtained three minutes after relaxation recovered to those of the beginning of clenching. These findings indicated that muscle fatigue may be induced in the SCM muscle during sustained voluntary clenching and that electromyographic power spectral analysis can be used as a noninvasive, objective, and quantitative index of SCM muscle fatigue.
Allergies caused by metals have been increasing. The number of patients visiting dentists with the chief complaint of metal allergy has also been increasing. From March 1994 to February 1997, 263 patients who complained of various symptoms visited our allergy clinic. Among them, 184 patients were suspected to have allergy caused by metals in dental restoration materials and were referred to the patch test. Among 165 patients', 128 were positives for metal allergy. Constituent elements of intraoral metals were analyzed in 107 of these 128 positive patients. The findings were as follows: 1. The most common five elements acting on the patients were Hg, Co, Ni, Cr, and Pd. 2. The most frequently used elements of dental restoration metal materials were Zn, Ag, Cu, Au, and Pd, and the alloy was Au-Ag-Pd alloy. 3. The highest tendency of coincidence between allergen and intraoral metals were observed among Co-Cr-Ni alloys and Pd, Ni, and Cr elements. 4. In case of palmoplantar pustulosis, allergen metals tended to be the same as intraoral metal elements.
The purpose of this study was to clarify the effect of covering gingival sulcus with denture base on periodontal tissue. Six subjects participated in this study. An experimental denture was inserted to a test tooth of each subject that was prepared for a full crown. Each experimental denture was designed to cover the gingival sulcus around the tooth. All subjects used them for two weeks. The parameters were as follows: 1) pH in gingival sulcus, 2) amount of gingival crevicular fluid, 3) tooth mobility, 4) temperature in gingival sulcus, 5) probing depth, 6) GI, and 7) PlI. Measurements were performed during the following periods: 1) pre-examination, 2) after cementation of provisional restoration, 3) during insertion of experimental denture, 4) after cementation of final restoration. A repeated-measures ANOVA was used for statistical analysis. The results were as follows: 1. pH value and amount of GCF increased after insertion of the experimental denture, and returned to same level as pre-examination after cementing of the final restoration. 2. Tooth mobility decreased during insertion of the experimental denture. 3. The changes of the other parameters were not significant. These results suggested that subclinical inflammatory change occurred in periodontal tissue in an early stage accompanied with covering of the gingival sulcus.
The purpose of this study was to develop a measuring system for bone mineral density (BMD) using computed radiography and to measure BMD distribution in the edentulous mandible. Nine 2-3mm thick sequential cross-sectional bone slices were obtained from five cadaveric mandibles. Each slice in cross-sectional view on X-ray image was divided into 64 elements and BMD distribution was investigated. The results were as followed: 1. BMD measuring system: The accuracy was 1.4% (relative error) and the reproducibility was 1.1% (CV) . 2. BMD distribution in edentulous mandible: 1) BMD varied from slice to slice, decreasing from anterior to posterior in both cortical and cancellous bone on the inferior and lingual side. The BMD of buccal cancellous bone was relatively higher than that of the lingual side and remained fairly constant throughout. The BMD of buccal cortical bone showed a slight posterior increase. 2) Greater individual variation of BMD was observed near mental foramen, and in incisor lingual and inferior cancellous bone. Our system demonstrated excellent precision and reproducibility. BMD distribution varied near regions of muscle attachment and the mandibular canal. Further, it was suggested that strong implant stability in the molar region may be obtained by installation of the fixtures in the buccal cancellous area.