Novel patient-specific helical maxillary distractor: an in vitro feasibility study

At present, stock linear distractors are used for internal maxillary distraction osteogenesis. However, the authors' research group has demonstrated, through an in silico analysis, that linear distraction leads to bone deformities and malocclusion, whereas helical distraction can yield ideal outcomes. A system for designing and manufacturing custom helical distractors has recently been developed, and the feasibility of these appliances now needs to be assessed. This study was, therefore, conducted to gain an initial insight into their feasibility. The study had two goals. First, it aimed to demonstrate, in an in vitro model, that the novel system of custom helical distraction can produce appropriate clinical outcomes. The second aim was to compare the performance of custom helical distractors with that of stock devices and hybrid devices (i.e., linear appliances that feature patient-specific footplates). Interpreting the results as trends, this study showed that the system of custom helical distraction resulted in in vitro outcomes that were superior to those obtained with stock and hybrid devices.