Pain and instability during biting with mandibular implant-retained overdentures

We tested in a randomized controlled clinical trial the effect of pain and instability of dentures on bite force with different degrees of mucosal support. The trial involved 3 groups who had received: 1) a new conventional denture (CD-group), 2) an implant-mucosa-borne overdenture on 2 IMZ implants (IMZ-group) or 3) a mainly implant-borne overdenture retained by a transmandibular implant (TMI-group). Fifty-three women and 15 men, mean age 59 years, participated in this study. Bite force measurements were made unilaterally with a transducer and bilaterally with a bite fork. After the measurements, subjects were asked whether or not biting had caused pain or tilting of one of the dentures. Significantly more complete-denture wearers reported pain. They reported more frequent pain in the mandible than in the maxilla (P<0.001), whereas implant-groups seemed to experience more often pain in the maxilla. On the transducer, maxillary dentures of the CD-group tilted less (P<0.01) and mandibular dentures more (P<0.05) compared to the implant-groups. With the bite fork, tilting occurred more often in the incisal-cuspid area than in the molar region (P<0.001). No effect of pain and tilting was observed on maximum bite force. It appears that oral implants used to stabilize mandibular dentures permit subjects to exert higher bite forces