Influence of Crown-to-Implant Ratio on Stress Around Single Short-Wide Implants: A Photoelastic Stress Analysis

• Published in: Journal of prosthodontics Vol. 24; no. 1; pp. 52 - 56
• Main Authors: Sotto-Maior, Bruno Salles, Senna, Plinio Mendes, Silva-Neto, João Paulo da, de Arruda Nóbilo, Mauro Antônio, Cury, Altair Antoninha Del Bel
• Format: Journal Article
• Language: English
• Published: United States Blackwell Publishing Ltd 01.01.2015; Wiley Subscription Services, Inc
• Subjects: biomechanics; crown-to-implant ratio; Crowns; Dental implant; Dental Implants; Dental Porcelain - chemistry; Dental Porcelain - therapeutic use; Dental Prosthesis Design; Dental Prosthesis, Implant-Supported; Dental Stress Analysis; Dentistry; Elasticity; Humans; photoelastic stress analysis; Photography; short-wide implant; Stress, Mechanical; ultrashort implant; ultrashort implant; short-wide implant; biomechanics; photoelastic stress analysis; crown-to-implant ratio; Dental implant
• ISSN: 1059-941X; 1532-849X
• DOI: 10.1111/jopr.12171

Purpose The aim of this study was to evaluate the photoelastic fringe patterns around two short‐wide implants supporting single crowns with different crown‐to‐implant (C/I) ratios. Materials and Methods External hexagon (EH) cylindrical implants (5 × 7 mm) or Morse Taper (MT) conical implants (5 × 6 mm) were embedded individually into photoelastic resin blocks. Each implant received a single metal‐ceramic crown, with a C/I ratio of 1:1 or 2:1 (n = 10). Each set was positioned in a polariscope and submitted to a 0.5 kgf compressive load, applied axially or obliquely (30°). The polariscope images were digitally recorded, and based on isoclinal and isochromatic fringes, the shear stress was calculated at 5 predetermined points around each implant. Data were analyzed by two‐way ANOVA (α = 0.05). Results Under axial loading, the stress was concentrated at the crestal region, and there were no differences between C/I ratio or implant types. In contrast, under oblique loading, EH implants showed lower stress values than the MT group and the 2:1 C/I ratio showed higher stress concentration for both implant types (p < 0.05). Moreover, MT implants showed stress distribution through a higher area than the EH implant did, with a tendency to direct the stress toward the implant's apex under oblique loading. Conclusion MT conical short‐wide implants showed higher stress values that were distributed through a higher area directed to the implant apex. The C/I ratio influences the stress distribution only under oblique loading.