COMMINUTION OF FOOD WITH MANDIBULAR IMPLANT-RETAINED OVERDENTURES

When complete-denture wearers are treated with from four to six implan ts and mandibular implant-borne prostheses, masticatory performance im proves. No significant improvement has been observed with two implants and implant-mucosa-borne overdentures, suggesting that the masticator y performance of edentulous subjects depends on the degree of support for their mandibular prostheses by implants or alveolar mucosa. To ver ify this hypothesis, we studied, in a randomized clinical trial, the c omminution of an artificial test food during mastication The trial inv olved the provision of a new maxillary denture and either a new conven tional mandibular denture, a mandibular overdenture retained by two pe rmucosal cylindric implants through a single bar-clip attachment, or a mandibular overdenture retained by a transmandibular implant through five clips on a triple-bar construction with cantilever extensions. In comparison with the subjects wearing mandibular implant-retained over dentures, the subjects with conventional complete dentures needed betw een 1.5 and 3.6 times more chewing strokes to achieve an equivalent re duction in particle size. No differences in masticatory performance an d efficiency were found between the subjects who had received two perm ucosal cylindric implants and those who had received a transmandibular implant. The results suggest that the increased retention and stabili ty of the mandibular denture, rather than the degree of support by imp lants or alveolar mucosa, determine the wearer's ability to comminute food during mastication.