Influence of wrong determination of occlusal plane in maxillary advancement: a model surgery study

Abstract

Aim: This study investigated whether an occlusal plane error of acquisition can influence on the treatment planning of maxillary advancement in double-jaw surgeries. Methods: Advancement of 8 and 4 mm were studied in different groups. For each group, 20 maxillary models were mounted by a 13-degree platform with superior articulator arm (control group) and other 20 models mounted with 7 degrees (study group). Intermediate splint was obtained by cast surgery performed in the control group. All the 40 maxillary models were remounted with this intermediate splint. Measurements in vertical and anteroposterior planes were accomplished pre- and postoperatively by digital caliper rule and Erickson’s platform. Results: Statistical analysis showed significant results in two planes. The alteration of occlusal plane from 13 degrees to 7 degrees modified the final result in vertical measurements: right molar from group of 4 mm advancement (p<0.0001) and left molar from two groups of advancement (p<0.0001); in anteroposterior measurements: maxillary incisor from 4 mm of advancement (p<0.005) and 8 mm of advancement (p<0.0001). Conclusions: Notwithstanding the importance of statistical findings, the result probably did not show clinical relevance in orthognathic surgery. Clinical studies addressing these concerns must be supplied in scientific literature.