Dose requirements for propofol anaesthesia for dental treatment for autistic patients compared with intellectually impaired patients.

We had clinical grounds to suspect that patients with autism had greater propofol requirements during dental procedures than patients with intellectual impairment without autism. This hypothesis was tested by an audit of a standard anaesthetic technique. The audit was approved by our Hospital Ethics Committee. We compared the propofol requirements and effect using a standardised protocol during dental treatment in 56 autistic patients (age range three to 35 years) and 56 intellectually impaired patients (age range four to 42 years). Patients in each disability group were divided into three subgroups by age: six years or younger, seven to 19 years and 20 years or older. Combative patients received oral midazolam premedication, other patients received a single intravenous bolus of midazolam at induction. Otherwise, standardised propofol boluses and infusion were the only anaesthetic agents used. The propofol infusion rates of the intellectually impaired group showed significant decline with age (propofol rate of requirement mg x kg(-1) x h(-1), mean [SD]): < six years 13.6 (3.6), seven to 19 years 9.5 (3.0) (P = 0.008 cf < six years group), > 19 years group 8.5 (2.4) (P = 0.001 cf < six years group). The propofol requirement was greater in the autism group than in the intellectual disability group, and the proportion of the cases where bolus propofol administration was needed after induction was significantly higher in the autistic patient group than in the intellectually impaired patients (P < 0.002). This suggests that autistic patients have greater propofol requirements for anaesthesia during ordinary dental treatment compared with intellectually impaired patients.

[The mean of Downs and northwestern analysis in adults].

An angle analysis and linear analysis are popularly used in clinical orthodontics. Downs analysis and Northwestern analysis are two methods of angle analysis, and the mean values reported by Iizuka in 1963 are still used. However in Japan each generation's constitution (height, weight) tends to increase year by year. For example, the mean height and weight of adult males (23 years old) have increased by 5.0cm and 7.6kg as compared with nearly 20 years ago. Therefore the mean of 20 years ago may not be appropriate. Analytical values at normal occlusion Japanese adults by Kayukawa, Iizuka, Ishikawa, Yamauchi, Miura, Iwazawa and, most recently by Asai in 1973. We obtained these values and determined the validity of currently used values.

Estimation of the gonial angle from the orthopantomogram.

We set a new basic plane on an orthopantomogram in order to measure the gonial angle and obtained the following: 1) Usable error difference in ordinary clinical setting ranged from 0.5 degrees-1.0 degree. 2) Because there is no great difference between the levels of the gonial on orthopantomograms, they are effective for investigation of the changes of side and degree. Thus, based on the above results, 100 cases were randomly selected from the Angle class III cases which were treated at our department of orthodontics in order to investigate the differences between the left and the right side and pre and post-treatment changes and obtained the following results: 1) Pretreatment differences between the right and the left sides were recognized in 88 cases. 2) 66 cases showed posttreatment improvement in the differences between both sides. Because orthopantomograms are applied at the end of treatment and for evaluation of the stability of occlusion. We will investigate if the occlusion is best harmonized at equal gonial angles on both sides, using a combination of EMG and measurement of occlusion force, and will also study various cases in more detail.

[Case report of crowding treated without extraction].

In orthodontic diagnosis, one of the most important factors is to decide whether to extract or not to extract the permanent tooth. There are many so-called borderline cases. This difficulty is caused by his growth which can not be foreseen perfectly. We treated a borderline case without extraction, and established good occlusion.

[Investigation of an electromyogram and a mandibular movement in prognathia of mixed dentition compared with normal occlusion].

A quantitative analysis of EMG activity in temporal and masseter muscle and of mandibular movement was performed in prognathia (n = 20) and normal (n = 30) occlusion. EMG recordings were analyzed during rest position, maximal clenching and maximal clenching with a cotton-roll. Mandibular movement was examined for path of closure, amount of freeway, maximal velocity of jaw opening and closing, condylar test and amount of maximal vertical jaw opening. The results of the investigation revealed the following. Normal occlusion and prognathia were classified into two groups by path of closure. One group was going toward the upper front and another toward the upper back. The former was indicated in 77% of normal occlusion and 65% of prognathia cases examined. Amount of freeway space was the same in both groups. Maximal velocity of jaw was significantly (p less than 0.05) faster for prognethia than for normal occlusion. Condylar test was significantly (p less than 0.05) greater for prognathia than for normal occlusion. Temporal muscle activity was greater for normal occlusion than for prognathia. During maximal clenching, temporal muscle activity was greater than masseter activity in the normal occlusion. A tendency toward negative correlation was found between temporal muscle activity during maximal clenching and the mandibular plane angle, facial height and gonial angle. The same tendency was found between masseter muscle activity and the mandibular plane angle, facial height, ramus-height and gonial angle. These results prove that it is important to examine muscle activity and mandibular movement to make treatment planning.