RESUMO
Examinations of the retention of lower individual trays without formation of borders and with borders shaped of wax for impressions have been carried out in 32 patients with toothless mandible. The retention of impressions and lower complete dentures has also been examined. The examinations have been demonstrated that formation of lower individual impression trays' borders increases the retention of lower complete denture. The formation of borders in the anterior region of sublingual fovea influences the retention of lower complete dentures most. Simultaneous formation of borders in the anterior regions of sublingual salcus and oral cavity vestibule ensures the greatest retention of the dentures. The retention of lower complete dentures shows positive correlations with the retentions of impression trays and impressions and that is why the estimation of the impression's retention of the toothless mandible should be done each time to determine the recommendations for the end of the procedure or performance of suitable corrections. Carrying lower complete dentures for 1-4 weeks doesn't influence the retention force of these dentures.