Study of mandibular movements during speech.

We recorded the mandibular movements produced during the reading of a text, in Spanish, using a kinesiograph in a random sample of 71 people aged 24 to 35. In each recording we measured nine variables and did a descriptive analysis of each variable. Our findings support that the mandibular movement during speech has some definite characteristics. The most important fact is that it could be a high percentage of occlusal contacts at incisal level during speech. This has to be taken into account when exploring an occlusal trauma of unknown etiology.

Study of the mandibular movements during swallowing.

The authors recorded the mandibular movement produced during the swallowing of 150 ml of water with the aid of a straw between the lips using a kinesiograph in a random sample of 66 people between the ages of 24 and 35. In each recording 13 variables were measured, and a descriptive analysis of each one was carried out. The authors' findings support that there is no dental contact during liquid swallowing with the aid of a straw between the lips.

Reproducibility of lateral excursive tooth contact in a semi-adjustable articulator depending on the type of lateral guidance.

The purposes of this study were (i) to compare the reproducibility of lateral tooth contacts of casts mounted in a semi-adjustable articulator when condylar guidance was set by different methods and (ii) to assess the margin of error of the variations of condylar guidance without changing lateral tooth contacts, depending on the type of lateral guidance. In subjects with different types of lateral guidance, intraoral lateral tooth contacts identified with occlusal registration strips were compared with those identified by use of a semi-adjustable articulator, setting the condylar guidance in four different ways: using protrusive wax wafers, by axiography and by adding and subtracting 5 degrees from the value of condylar guidance obtained by protrusive wax wafers. Tolerance to variations of condylar guidance without changing lateral tooth contacts was determined by increasing and decreasing the value of condylar guidance until lateral tooth contacts changed. Different ways of setting condylar guidance on a semi-adjustable articulator give rise to different values of condylar guidance in the same subject. The occlusal repercussions of these variations of condylar guidance values depend on the type of lateral guidance. Canine protection had the greatest tolerance to variations in the setting of condylar guidance without changing lateral occlusal contacts.