This study assessed the thresholds of orofacial touch and pressure sensation in children and compared them with those in adults. Child subjects who were outpatients of TMDU Dental Hospital and who had no particular systemic diseases other than dental problems, were classified into 4 groups : preschool children (4-5 y, n=26), lower grade elementary school pupils (6-9 y, n=100), higher-grade elementary school pupils (10-12 y, n=36), and junior high school pupils (13-15 y, n=26) . Adult subjects were TMDU students (23-31 y, n=37) . The thresholds of touch and pressure sensation were measured with a Semmes-Weinstein pressure aesthesiometer which consisted of 20 filaments with different marking values (Fm) . Stimulation was applied with the thinner 10 filaments with lower values ranging from 1.65 to 4.31 Fm (0.0045-2.052 gw) . The measurements were carried out on the following 10 points in the orofacial area in all the subjects the upper lip, gingiva of upper anterior teeth, palate, lower lip, gingiva of lower anterior teeth, buccal mucous membrane, tongue tip, skin above eyebrow, cheek skin and mentum skin. The thresholds in the child subjects were not different from those in the adult subjects on most measurement points, but were significantly different on the gingiva and palate. The lower the age, the lower the thresholds on the gingiva. Since these measurement points are located in the chewing mucous membrane, it is considered that the threshold changes occurred due to histological alterations with growth. It is suggested that the threshold values of orofacial touch and pressure sensation obtained from this study could be used as the standard values for an indicator of the development of oral function and structure in children.
The purpose of this research was to clarify the structural changes according to the aging of the buccal mucous membrane in the elderly. Thirty-eight Japanese adult cadavers (62-98 years) which dental students had used for anatomy practice were used as materials. Serial sections were made from the specimens of the buccal mucous membrane in the vicinity of angelus oris removed from the cadavers, and the sections were observed with a light microscope. The results were as follows : 1) As for the buccal mucous membrane in the vicinity of angulus oris in the elderly, the thickness decreases significantly with aging. 2 ) In the buccal mucous membranes of the elderly, the functional arrangement of the collagenous and elastic fibers distributed in the lamina propria and the submucous membrane disappears with aging, and the fibrosis tendency generally becomes remarkable. 3) The number of blood vessels distributed in the mucous membrane in the vicinity of angulus oris of the elderly decreases with aging, and the distribution of blood vessels changes, too. It seems that these changes suppress the circulatory system of the buccal mucous membrane in the very elderly. 4) The fatty change and the fibrosis of the small salivary gland progress among the very elderly. It seems that the structural change of such a glandular tissue causes dryness in the mouth. 5 ) The change in the thickness of the tunica muscularis according to aging was hardly seen among the elderly. However, the tendency toward thinness with aging was seen, as for the muscular fiber. The structural change of such a muscular fiber seems to cause depression such as that of the orbicular muscle of the mouth in the elderly.
This study evaluated the effect of titration in oral appliance therapy for obstructive sleep apnea syndrome (OSAS), and examined problems with this test. However, the method of predicting the appropriate mandible position has not yet been established. In this study, titration was attempted in order to predict appropriate mandible position prior to wearing an oral appliance. Twenty-three male patients diagnosed as OSAS by a physician participated in this study. The mandible was protruded by a titratable splint (TS) until apneic and hypopneic signs had disappeared. Moreover, polisomnography (PSG) was used to monitor brain wave patterns, eye movement, muscle tone, body movement and breathing. Sleep study was performed by a portable sleep monitoring device before and after examination wearing titrated oral appliance (OA), and the effect of therapy was evaluated. The results obtained were as follows. 1. In the Apnea Hypopnea Index (AHI), Apnea Hypopnea density (AH density), lowest SpO2, Oxygen Desaturation Index (ODI), there was a statistically significant improvement. The mean AHI reduced from 13.8 to 4.7 (p<0.001) . The mean AH density reduced from 12.0 to 3.5 (p<0.001) . The mean lowest SpO2 increased from 78.7 to 84.7 (p<0.0001) . The mean ODI reduced from 15.7 to 6.1 (p<0.001) . 2. The average proportion of protrusive distance for movable distance was 71.7%. 3. Only one patient complained of discomfort in the maxillofacial region, however, this discomfort disappeared after adjustment of OA. Therefore, it is suggested that titration for OA is a very useful examination for OSAS therapy.
The role of complete dentures in masticatory function is well established, but their effect on swallowing has been little examined. This study investigated the effect of complete dentures on swallowing in the elderly. Lateral projection videofluorography (VF) was performed for nine healthy edentulous elderly volunteers (mean age 73.9±2.9 years) while they swallowed 8 ml of liquid and paste barium with and without complete dentures. A total of 35 VF records were analyzed for temporal and spatial measurements of oropharyngeal motion during swallowing. The tongue tip contacted the inside of the lip between the upper and lower alveolar ridges during swallowing without but not with complete dentures. The hyoid moved further upward (P=0.002) during swallowing without dentures (liquid : 5.85±3.99 mm, paste : 6.41±5.25 mm) than with dentures (liquid : 3.70±4.57 mm, paste : 3.69±4.07 mm) . The larynx moved further forward (P = 0.044) during swallowing without dentures (liquid : 6.39 ± 2.58 mm, paste : 6.46 ± 2.87 mm) than with dentures (liquid : 5.34 ± 2.04 mm, paste : 5.93±1.50 mm) . The timing of the movements of these structures was not affected by the presence of the dentures or bolus consistency. These results showed that the hyoid and larynx moved more in swallowing without than with complete dentures, perhaps because of tongue tip protrusion when not wearing dentures. These findings suggest that complete dentures have a significant effect on swallowing function as well as masticatory function in elderly individuals.
We developed and evaluated a new method of titanium surface treatment for direct bone fixation of implants. This method consists of hydroxyapatite (HA) flame coating onto a porous titanium surface which is arc-sprayed with pure titanium material in argon gas at atmospheric pressure. The surface roughness of the porous layer was 360 μm, Rmax, and showed higher resistance to blast erosion in comparison with the conventional low-pressure plasma-sprayed porous layers of titanium. The thickness of the HA layer was between 20 and 40 μm considering the balance of bone conduction effect of HA and the possibility of mechanical detachment of the layers from the porous titanium. Short-term animal tests showed excellent results. This new surface treatment method was applied to cementless total hip joints which were used clinically. The results obtained from observations of the retrieved specimens show that the thickness of the HA coating layer is sufficient for the new bone formation after implantation. It was concluded that the new surface treatment method for titanium alloy implants is effective and successful for direct bone fixation.