Statement of problem: The influence of the loss of posterior teeth on the condylar position and on temporomandibular disorders (TMDs) remains a controversial issue.
Purpose: This study investigated whether prosthetic rehabilitation promoted modification of the condylar position in subjects without symptoms of TMDs.
Material and methods: The temporomandibular joints (TMJs) of 12 women (age 37 to 74), all with existing maxillary complete dentures but no removable partial denture (RPD) restoring the Kennedy class I partially edentulous mandibular arch and no clinical signs of TMDs according to the criteria established by Helkimo, were viewed in maximal intercuspal position with corrected lateral tomography before and after prosthetic rehabilitation with a new maxillary complete denture and a mandibular RPD. Before prosthetic rehabilitation, a mandibular stabilizing base was fabricated to prevent the existing maxillary complete denture from dislodging during tomographic examination. Two methods were used to evaluate tomograms: (1) linear measurements of the subjective narrowest anterior and posterior intra-articular joint spaces made from the tomograms by use of a digital caliper and (2) linear measurements of the anterior and posterior intra-articular joint spaces on the basis of drawings and tracings. Repeated-measures analysis of variance followed by orthogonal contrasts were used to evaluate differences between measurements carried out on the same subject under the different test conditions of the study (before prosthetic rehabilitation, before prosthetic rehabilitation with a mandibular stabilizing base in position, and after prosthetic rehabilitation) (P<.05).
Results: Before prosthetic rehabilitation, a predominance of posterior condylar positions was observed. Before prosthetic rehabilitation with a mandibular stabilizing base in position, a significant decrease was observed in posterior condylar positions (P=.03). This decrease was more marked after prosthetic rehabilitation (P=.02). The subjective evaluation and comparison on the basis of drawings and tracings used to analyze the tomograms produced similar results (P=.70).
Conclusion: Within the limitations of this study, significant changes in the condylar position occurred after prosthetic rehabilitation in subjects without symptoms of TMDs.