Comparison of two treatment strategies for the early treatment of an anterior skeletal open bite : Posterior bite block-vertical pull chin cup (PBB-VPC) vs. posterior bite block-high pull headgear (PBB-HPH).

PURPOSE

Aim of the present study was to compare the effects of posterior bite block-vertical pull chin cup (PBB-VPC) and posterior bite block-high pull headgear (PBB-HPH) in the early treatment of anterior open bite.

METHODS

This retrospective study was carried out using pretreatment (T1) and posttreatment (T2) lateral cephalometric radiographs of 28 patients treated with either PBB-VPC or PBB-HPH and 14 age-matched control patients with anterior open bite. The treatment changes were evaluated with 20 measurements (7 angular and 13 linear). Intergroup comparisons of the cephalometric measurements were performed by ANOVA, and a post hoc Tukey test was used to perform multiple comparisons.

RESULTS

There was no significant difference in the open bite correction between the two treatment groups, but both groups showed significantly greater increases in overbite than the controls (P < 0.01). The PBB-HPH group showed more upper incisor retraction than the control group (P < 0.01). The two treatment groups both showed significantly more lower incisor retraction than the controls, and more retraction in the PBB-HPH group was found (P < 0.001).

CONCLUSIONS

Both PBB-VPC and PBB-HPH were effective in the early treatment of anterior open bite. Retrusion of the upper/lower incisors and a slight increase in the upper anterior dentoalveolar height were the most evident findings in the PBB-VPC group. In the PBB-HPH group, forward maxillary growth was significantly restricted, ANB and overjet were reduced, and the upper and lower incisors were significantly retruded.