Sectional impressions for mandibular distal extension removable partial dentures.

STATEMENT OF PROBLEM

Corrected impression procedures provide the best possible support to be gained from an edentulous ridge for a removable partial denture, but they are time-consuming and technique-sensitive.

PURPOSE

An experimental mandibular distal extension removable partial denture was used to measure the vertical movement of denture bases during biting.

MATERIAL AND METHODS

Five patients participated for whom vertical movement of denture bases was measured by comparing the thickness of plaster interocclusal records made with the denture at rest and under biting pressure. Denture bases were processed on master casts formed from final impressions made in full arch custom trays. Secondly, bases were readapted using sectional relining impressions with the same regular body polysulfide impression material.

RESULTS

Statistical analysis of the vertical movement of denture bases during biting at 4 points on the right and left denture bases showed a significant decrease in vertical movement with sectional impression. The reduction was less than a 0.1 mm, a result that questions the routine use of sectional impression for every distal-extension mandibular removable partial denture.

CONCLUSION

Supportive form of distal-extension edentulous ridges can be recorded successfully by full arch impressions in custom trays.