[in Japanese]

View full abstract

It is generally known that the centric position was used to take bite registration and adjust occlusion. However, mandibular position is influenced not only by opening muscles and elevating muscles, but also by the muscles of facial expression. The purpose of this study was to examine the influence of the muscles of facial expression on centric position. The subjects were 3 normal adults using the Gnathohexagraph measuring system. They were required to track their angles of the mouth posteriorly from the centric position. The deviations of the condyler position were recorded. The results showed that the level of tension of the muscles of facial expression were responsible for posterior/upwards deviations of the mandibular position.

View full abstract

The purpose of this study was to examine the influence of a working condylar path adjustment system. Lateral border movement were measured from -30 degrees to +30 degrees at the working condylar angle, and the working canine path and angle were analyzed using Gnathohexagraph simulation.
The results were as follows:
1. When the working canine path moved 1.2 mm, the working condyler angle changed by 60 degrees.
2. When the working condylar angle changed from -30 degrees to +30 degrees, the working canine angle changed by 15 degrees.

View full abstract

A sleep apnea syndrome (SAS) is one of the most common diseases. The respiration of SAS patients stops in sleeping, and it causes many diseases. In the USA, the position of dentists on SAS has been established, and dentists have cooperated with medical doctors. In Japan, however, SAS is almost unknown among dentists. So, I report about a dental approach to SAS, and I hope the understanding of SAS will be deepened among dentists.
One of dentists' roles on SAS is to diagnose craniomandibular abnormality of SAS patients with lateral cephalograms. SAS patients have (1) dolico facial pattern (long face), (2) low positioned hyoid bone, (3) normal positioned maxilla and retruded mandible, (4) long soft palate and (5) narrow airway, and sometimes have tonsils and/or adenoids.
The other dentist's role on SAS is to treat with oral appliances (OA) . There are two types of OA; one is the sleep splints type and the other is the tongue retaining device (TRD) type. A purpose of OA is to advance the mandible and the tongue, and to expand the airway of SAS patients. However the mechanism, the indication, and the quantities of advancement are not clear. So we will continue studies on OA about these points as we have done.

View full abstract

[in Japanese]

View full abstract

Silicone impression materials are often used clinically because of their stability in dimensional precision. We performed layering impression (Korrekturabdruck) using putty type and injection type silicone impression materials. By this impression method, initial impression is performed without a spacer. After removal of the initial impression, grooves are made on the impression surface using a groove-cutter, and secondary impression is performed. This technique resulted in clear impressions and preparation of highly compatible prostheses.

View full abstract

[in Japanese]

View full abstract

[in Japanese]

View full abstract