RESUMEN
OBJECTIVES: The aim of this crossover study was to compare clinical denture base deformation with different attachments used for mandibular implant overdentures. MATERIALS AND METHODS: Twenty-four patients with edentulous mandibular ridges received two implants in the former canine regions. Three months thereafter, each patient was randomly given the following implant overdentures in a crossover design: (a) bar implant overdentures (BOD), (b) resilient telescopic implant overdentures (TOD), and (c) stud implant overdentures (SOD). Six linear strain gauges were attached to the lingual surface of the implant overdentures opposite to the abutments (Ch1and Ch2 at clenching [left] side and Ch5and Ch6 at non-clenching [right] side) and at midline (Ch3 and Ch4). Three months after wearing each implant overdenture, strain registrations were performed during clenching without food and during clenching on soft (cake) and hard (carrot) foods. Kruskal-Wallis test was used to compare denture strains between group, channels, and clenching conditions. RESULTS: Bar implant overdentures showed significantly higher (p < .001) total microstrains (403.7 ± 306.8 µÉ) than TOD (146.9 ± 131.8 µÉ) and SOD (99.8 ± 75.6 µÉ). No difference in microstrain was noted between TOD and SOD (p = .06, n.s.). Channels opposite to the abutments at clenching side (ch2) recorded the highest total strain during clenching hard (390.4 ± 381.6 µÉ) and soft (223.5 ± 220.2 µÉ) foods. Clenching hard food was associated with significant higher total microstrain than clenching soft food (p = .002). CONCLUSION: Telescopic and stud attachments are recommended to be used for two-implant mandibular over dentures as they were associated with reduced denture base deformation compared with bar attachments.