Pressure Center Displacement Variation in Subjects With Different Mandibular Over-dentures

Objectives: A comparative kinematic analysis was performed on subjects with mandibular over-dentures at different heights to determine the center of pressure displacement (CPD).
Methods: 22 consecutive healthy male subjects between 18 and 25 years (mean age 22±0.13) conformed the sample. Subjects with systemic muscle pathology, abnormalities of the cervical spine alignment, genuvarus, genuvalgus, with flat feet and / or cavus, mouth breathers, with rotated hip, oral prostheses and orthodontic treatment were excluded. A kinetic evaluation with a force plate was used to determine the CPD in subjects with acrylic over-dentures of 2, 4 and 6 mm height adhered to the mandibular teeth with denture adhesive. The subjects were placed in his usual position standing on a platform (Kistler®) and CPD was determined in mandibular postural position (PP), in habitual occlusion (O), and occluding with a 2, 4 and 6 mm height over-dentures. Wilcoxon test was performed to compare PP with O and both measures with different heights of over-dentures.
Results: Regarding axis X: average CPD was 0,1931 cm (±0,0482) in rest position and 0,1627 cm (±0,0341) in occlusion (P=0.03). With the use of over-dentures, average of CPD was 0,1718 cm (±0,0438) with 2mm height (P>0,05); 0,2522 cm (±0,1071) with 4mm height (P<0,05); and 0,1418 cm (±0,0314) with 6mm height (P<0,05). Regarding axis Y: average CPD was 0,3761 cm (±0,0561) in rest position and 0,3343 cm (±0,0677) in occlusion (P=0.03). With the use of over-dentures, average of CPD was 0,2706 cm (±0,0351) with 2mm height (P<0,05); 0,1998 cm (±0,0901) with 4mm height (P<0,05); and 0,3121 cm (±0,1208) with 6mm height (P<0,05).
Conclusions: Assuming that the position of the head and the body plays a role in the body balance represented by the center of pressure displacement variations, a 4mm height of mandibular occlusal over-denture evidence a significant decrease of the CPD magnitude in anterior-posterior sense.