Long-term stability of the lower labial segment relative to the A-Pog line

Cephalometric records of 47 cases treated with the Begg technique were examined with a view to assessing both the effects of treatment and long-term change. The cases were treated by a single operator (Dr H. Brouwer) whose long-term records were taken on average over 10 years out of retention. Special reference was made of the use of A-Pog line as a guide to lower incisor stability. There was marked individual variation in both response to treatment and long-term change. Though all the results were clinically stable the A-Pog line was not found to be a reliable guide to lower incisor stability. In 62 per cent of the cases examined, the lower incisors tended to return towards their original positions after retention, whilst in the remaining cases the changes were extremely variable.