Comparison between linear and curved arrangement of Telescopic attachment used for 4 implants mandibular overdenture: A study of clinical deformity of denture base

Objective: The aim of this study was clinical evaluation of stresses developed in complete mandibular overdenture assisted by four implants using telescopic attachment placed in curved or linear configurations. Materials and Methods: Twelve completely edentulous participants were selected for the study and each patient received four implants. All patients were into 2 equal groups regarding implants position: The first group (Linear design): The four implants were installed at lateral incisor and canine areas. The second group (Curved design): the four implants were installed bilaterally in the interforaminal region of the mandible (at canine and second premolar areas). The implants were connected to the overdentures with resilient telescopic attachments. Eight strain-gauges were adhered to the polished surface of each denture using a special adhesive. The gauges were aligned horizontally parallel opposite to each attachment 1 and on lingual and buccal polished surface related to molar area2. Three months after wearing implant overdenture, strain registrations were performed during clenching without food. Strain gauges and multichannel strain-meter were used to compare denture strains between groups and channels. Results: For all channels, linear group recorded significant higher microstrains than curved group. For both groups there was a significant difference in microstrains between channels. Conclusion: Within the limitation of this short-term cross over trial, curved arrangement for mandibular implant assisted overdentures is recommended than linear arrangement as it reduced denture base strains and deformation during maximum voluntary clenching.