RESUMO
PURPOSE: This study aimed to compare, through photoelastic analysis, the distribution of stresses around narrow implants with external hexagon (EH) and Morse taper (MT) connections, when single crowns made with metal and ceramic abutments were used. MATERIALS AND METHODS: Six photoelastic models were prepared, simulating the use of narrow EH and MT implants replacing a lateral incisor. These 2 groups received 3 different abutments: prefabricated metal abutments, customized metal abutments, and customized zirconia abutments. All crowns were identical and made with a leucite reinforced glass-ceramic. Vertical loads of 0 to 100 N were applied on the palatal surface of the crowns, and the photoelastic stress fringes developed in each model were captured in a high-definition video, and digital photographs were taken at 100 N. RESULTS: The abutment type and material influenced the stress distribution patterns around narrow implants with EH and MT connections. Stresses were generated mainly around the apical and lingual regions of the implants. CONCLUSIONS: For both connections, the prefabricated metal abutments presented better stress distribution around the implants when compared to customized metal and zirconia abutments because low stress levels were developed in smaller areas around the implants.