Background: Post-dilation with kissing balloon dilation remains controversial in the 1-stent approach, but many technical improvements are possible to refine the final results. This study aimed to evaluate the results of different side-branch (SB) ostial treatments after main vessel stenting, including ostial optimization technique (OOT), simultaneous kissing balloon dilation (KBD) and single balloon dilation (SBD). Methods: Three different ostial side branch treatments (OOT, n = 5; KBD, n = 5; SBD, n = 5) were emulated in a synthetic bifurcated phantomusing a second-generation sirolimus-eluting stent (Firebird2TM, Microport, Shanghai, China). Micro-computed tomography (micro-CT) and optical coherence tomography (OCT) were performed to assess morphologies. Results: Compared to the non-OOT procedures (SBD and KBD), OOT was characterized by the sequential dilation of two snuggling balloons, creating a longer valgus struts length (OOT: 2.13 ±0.30 mm, SBD: 1.23 ±0.34 mm, KBD: 1.11 ±0.39 mm, p < 0.01), broader angulation between themain-branch and valgus struts axes (OOT: 42.72 ±0.91˚, SBD: 25.77 ±7.81˚, KBD: 31.78 ±1.34˚, p < 0.01), shorter neocarina length (OOT: 0.28 ±0.31 mm, SBD: 0.64 ±0.38 mm, KBD: 1.11 ±0.37 mm, p < 0.01), larger SB ostial area (OOT: 6.76 ±0.17mm2, SBD: 4.78 ±0.86mm2, KBD: 5.87 ±0.89 mm2, p < 0.01), and lower index of stent cell distortion (OOT: 6.67 ±3.33%, SBD: 10.67 ±4.23%, KBD: 20.00 ±5.29%, p < 0.01). In addition, the rate of severe strut malapposition was lower with the OOT procedure compared with the non-OOT procedures (OOT: 2.22 ±0.48%, SBD: 10.31 ±0.66%, KBD: 6.74 ±1.24%, p < 0.01). Conclusions: OOT, consisting of an initial proximal optimizing technique (POT) and sequential snuggling balloon dilation and then re-POT, significantly optimized the results of provisional bifurcation treatment. The physiological and clinical significance of our observations await further clarification.