Aim: To transfer strain optimized signals for chondrocytic differentiation and osteoblast proliferation for adaptive bone tissue modelling into an individualized multistep distraction protocol.
Methods: The study design was twofold: (1) bioinformatic transformation of cellular reactions into a mathematical model, and (2) a comparative randomized clinical study. (1) Data from load related bone regeneration studies and distraction studies based on animal models were analysed and transformed in a bioinformatic model. Based on this model a software application calculates time and extent of distractor activations necessary to grant near-constant optimized strain levels. (2) Healthy subjects (n=30) scheduled for palatal distraction were randomly assigned to the 'calculated protocol group' and compared to healthy matched control group (n=30) with 'non calculated protocols'. The following data were measured: total distraction time, tooth movement (diastema reduction), soft tissue effects, and pain rating (visual analog scale).
Results: Cell differentiation, apoptosis and tissue development highly correlates to a magnitude of 20,000 microstrains. In total, an average diastema reduction of 89% without orthodontics occured in the patient group compared to 58% in the control group. Soft tissue effects like bleedings were observed in both groups. Perception of pain correlates to the distraction distance but is notably less in the strain related protocol group.
Conclusion: Increased spontaneous diastema reduction proves normal bone formation within the distraction gap. The results indicate that strain optimized distraction protocols are superior to experienced based protocols.