The Effects of Heavy vs. Light Force Cervical Headgear

A sample of 27 cases treated with CHG were selected from the files of Rocky Mountain Data Systems, Inc. and Dr. B. Fletcher. The cases were divided into two groups according to forces used during treatment to initiate and continue distal molar movement. Group I consisted of 15.cases which had been treated by Dr. Ricketts using heavy cervical traction (250-500 grams); Group II included 12 cases which Dr. Fletcher had treated with very light cervical traction (120-240 grams). The measurements of distal molar movement, facial axis and maxillary depth were recorded for each of the groups and t-tests were used to compare the groups for treatment change. Correlation coefficients were also used to investigate the relationship between distal molar movement and facial axis opening, and distal molar movement and maxillary depth change during treatment. On the basis of the data obtained in this study, the following conclusions have been reached: In a majority of cases (75% of cases from both groups) distal molar movement can take place with little or no facial axis opening (≤2) using heavy or light cervical traction. Maxillary depth change is not correlated to distal molar movement in a linear manner. There is no significant difference between the use of heavy and light forces in treatment with CHG for the variables maxillary depth change, distal molar movement and facial axis change. Due to lack of T5 records in Group II, comparison between the two groups was no significant. The results of this study have the following clinical implications: (1) In approximately 75% of patients with mesio or brachy facial patterns, CHG can be utilized to achieve a class I molar with little or no mandibular rotation, but there are some patients who still open dramatically. This suggests the importance again of progress head films to monitor these patients. (2) The results further suggest the importance of progress films to determine maxillary depth reduction since there is not a linear correlation between distal molar movement and the anterior maxillary segment reduction. (3) There was no significant difference between heavy and light forces relative to the amount of distal molar displacement which suggest that length of time worn may play a more important role than force, in class II correction. (4) Another very important finding to the clinician was that you lose approximately 30% of class II correction during the retention phase of treatment. This strongly suggests the need for headgear wear during the retention phase to reduce the relapse problem