Pressure Center Displacement Variation With Mandibular or Maxillary Over-dentures

Objectives: A comparative kinematic analysis was performed on subjects with mandibular or maxillary over-dentures to determine the center of pressure displacement (CPD) when occluding.
Methods: 22 consecutive healthy male subjects between 18 and 25 ys (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 4 mm height adhered to the mandibular or to the maxillary 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), occluding with the mandibular over-denture and occluding with the maxillary over-denture. Wilcoxon test was performed to compare PP with O and both measures with the different 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 mandibular over-denture, average of CPD was 0,2522 cm (±0,1071), and with the use of maxillary over-denture, average of CPD was 0,2385 cm (±0,0630) (P=0,067). 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 mandibular over-denture, average of CPD was 0,1998 cm (±0,0901), and with the use of maxillary over-denture, average of CPD was 0,3600 cm (±0,0735) (P=0.00).
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 mandibular occlusal appliance of 4mm height should be use during day if there is a therapeutic indication.