Aim of the study: Ecological evaluation of the oral environment and bacterial and candidalgrowth when hard acrylic resin of the maxillary obturator bulb is changed with heat cured silicone.Materials and method: Patients with unilateral maxillary defects (class 1 Aramany classification) received a metal framework prosthesis with hard acrylic resin bulb (group 1) which was then replaced with heat cured silicone (Molloplast B) (group 2). Obtained swabs were cultivated on blood agar, Sabouraud dextrose and Macconkey medium and incubated for microbiological evaluation. Results: The difference between the two groups was insignificant, however patients were more satisfied with obturators lined with heat cured silicone.Conclusion: Both materials could be used for obturator bulb construction in maxillofacial cases, however longer follow up period is required.