Periodontal Breakdown, Orthodontic Movements and Pulpal Ischemia Correlations-A Comparison Between Five Study Methods

Area of Science:

• Biomaterials Science
• Orthodontics
• Biomechanics

Background:

• Assessing biomechanical behavior of dental pulp and neuro-vascular bundle (NVB) during orthodontic movements is crucial.
• Understanding ischemic risks associated with gradual horizontal periodontal breakdown is essential for safe tooth movement.

Purpose of the Study:

• To evaluate the biomechanical behavior of dental pulp and NVB during orthodontic movements under periodontal breakdown.
• To compare the accuracy of five numerical methods in assessing ischemic risks.
• To identify the most accurate method for simulating these biomechanical events.

Main Methods:

• Seventy-two models of second lower premolars from nine patients were used.
• Simulations involved 3 N of intrusion, extrusion, rotation, tipping, and translation.
• Five numerical methods (Tresca, Von Mises, Maximum/Minimum Principal, hydrostatic pressure) were applied in 1800 simulations.

Main Results:

• All methods indicated stresses below maximum physiological hydrostatic pressure (MHP) for 3 N forces, suggesting no induced ischemic risks in healthy tissues.
• Rotation was the most stressful movement, while translation was the least stressful.
• The NVB faced higher ischemic risks than dental pulp due to constant deformation; intrusion and extrusion posed the greatest risks to the NVB.

Conclusions:

• The Tresca and Von Mises methods demonstrated higher accuracy in assessing biomechanical behavior during periodontal breakdown.
• The Tresca method was identified as the most accurate among the five evaluated methods for this specific simulation.