A growth study in ramus height

Department

of Orthodontic

Abstracts

Edited DR.

communications ance of articles

All

-___-

J.

A.

SALZAIAA-N,

by NEW

YORK

CITY

concerning further information about abstracted or books for consideration in this department should Salzmann, 654 Madison Avenue, New York. ____-~- _-----

Abstracts

and Reviews material and the acceptbe addressed to Dr. J. A.

of Papers Presented Before the Research Section of the American Association of Orthodontists Washington, D. C., April 26, 1960

The Effectiveness of Posthypnotic Suggestion Upon Control of the TongueThrusting Habit in Relation to Trance Depth: By George Lynn Palmer. D.D.S., M.S., Univcraity Tenncssce.

of Tcnncsscc,

College

of Dentistry,

Memphis.

The effectiveness of posthypnotic suggestion in ‘controlling the tongucthrusting habit which occurs during the act of perverted swallowing VGLS appraised in relation to trance depth. The thirteen patients included in the study were able to arrest t,he tongucthrusting habit after four to five hypnotic sessions. A mcan of one hour and twenty-one minutes was spent with each patient durin, 0 the hypnotic sessions. Each case was evaluated clinica,lly, ccphalon~etrieally, and stat,isticzlly. Tllc difference between the original and final measurements in each cast W:IS attributed to the correction of the tongue-thrusting habit and to the subsequent partial spontaneous self-correction of the csisting open-bite and overjet relationship, except in those cases in which orthodontic movement of the incisors was involved. The range, mean, standard deviation, and standard error of the relationship of the maxillary central incisor to SN, the mandibular central incisor to PII, differcncc in orerjet, and difference in overbite were calculated for each patient. The “t” test was applied to determine whether a significant, difference csistcd bct,ween the original and final linear and angular mcasuremcnts. A significant difference was found at the 2 per cent (.02) level. Regardless of the tra,nce depth achieved, no additional fortification WN necessary to maintain the stable result after t,ho tongue-thrusting habit was arrcstctl. At the termination of the study, norm of the patients in whom tongue thrusting was arrested had relapsed. The mean number of days the habit. had been arrested was 315 per patient. No relationship could be demonstrated b+ tween the t,rance depth and the correction of the t,onguc-thrusting habit. 434 LOCHWOOD VILLAGE DALLAS, TEXAS.

A Growth Study in Ramus Height : Ey William University Carolina,.

of North

Carolina,

Gene Schneider, D.D.S., M.S., School of Dentistry, Chapel Dill, North

A lateral roentgenographic cephalometric investigation was undertaken on twenty-four white boys and twenty-two white girls at least 8 years of age but 228

ORTHODONTIC

\‘olume 47 Sumber 3

ABSTRACTS

AND

REVIEWS

229

not yet 9. X11 were of Northern European ancestry and were selected on the basis of their particular age and the fact that they were not receiving orthodontic treatment. Each subject was oriented in a IIigley head positioner for an open-mouth profile roentgenogram on two separate occasions, the second following the first by six months. Each roentgenogram was subsequently traced, and the linear measurement to be considered was recorded. A statistical analysis was made of the differences in the two measurements for boys and girls. The ramus height of the male is larger than that of the female at age 8, and there is no significant difference in growth increment between males and females for the six-month interval studied. Growth trends were not apparent from this study, because of the comparat-ively short time interval of the two measurements on each group. These data, howercr, will scI”ve as a base line for the longitudinal study projected. 45

DAVIE

CHAPEL

A Study

CIRCLE HILL,

N.

C.

of the Stability

of Orthodontic

Pfluger, D.D.S., B.S., M.S., University Memphis, Tennessee.

Treatment: By Werner Martin of Tennessee, College of Dentistry,

A critical analysis was made of the stability of twenty-one treated cases from the time retention was initiated to a time no less than six months after all retent,ion was discontinued. Tracings were made from lateral cephalometric roentgenograms. One tracing was made at the time of retention, and another was made during the postretention period. The average length of time that the patients studied had been out of retention was twenty-three months. The following angular measurements were made on each film : S-N-a, S-N-b, a-N-b, i to mandibular plane, 1 to SN, 1 to Frankfort horizontal plane to mandibular plane. The following linear measurements were made on each film: NP to -1, WC’ to 7, overbite, and overjet. Plaster casts made at the time the patients were placed in retention and casts made at the time of this study were used. The following linear mrasurements were made on each mandibular cast : intercanine width, intermolar width, and inside arch length. A statistical analysis was performed to evaluate the significance of the measurements obt,ained. This included the arithmetic mean, the standard deviation, the standard error, and the range. The “t” test was used to ascert,ain the significance of any differences found in the data. The 5 per cent level was selected as the division between significant and nonsignificant differences. Minor but significant changes were found in the following measurements: S-N-b, a-N-b, 1 -NS, overbite, mandibular intermolar arch width, and mandibular arch length. In the group of patients studied, the changes that occurred in the positions of the teeth during the postretention period were minor and did not destroy the functional or cosmetic benefits of the treatment; therefore, the results of the CRSCS studied were considered stable. 611

WEST

AUSTIN,

15~~ TEXAS

ST.