Periodontal biomechanics laboratory

Bone level and center of resistance

Explore how periodontal support changes the moment arm and initial inclination of an incisor.

Educational 2D model
Generated moment657 g·mm
M = F × d60 g × 10.9 mm
Distance to CRes10.9 mm
Visual inclination3.0°
Incisor with variable bone support and horizontal forceBone level, center of resistance, power arm, translation, and tooth inclination change with the three controls.60 gCResBone level
Bone loss: 0.0 mm CRes apical shift: 0.0 mm Parallel line of action
Simulated initial responseTranslation and inclination toward the force
Force positionAt bracket level

Interpretation

What does the simulator show?

As alveolar support is lost, the center of resistance shifts apically. If the force remains at bracket level, the perpendicular distance to the CRes increases and so does the generated moment. Moving the line of action closer to the CRes reduces rotation and favors bodily movement; moving it away increases inclination. Increasing force proportionally increases the visual response.

M = F × d Moment = force × perpendicular distanceUnit: g·mm Force expressed in gram-force

Scope: this is an educational model of initial displacement. Angles are comparative and do not predict clinical movement, speed, or individual periodontal response.