Objectives: the work was to determine the maxillary tissue changes under acrylic and flexible lower tooth supported overdentures.
Methods: The study was accomplished on 20 patients; the selected cases were upper completely edentulous and lower tooth supported one. lower overdenture supported with canines bilaterally. The cases randomly split into two groups: Group I; ten patients wear acrylic complete upper denture and acrylic mandibular tooth supported overdenture Group II; ten patients wear flexible complete upper denture and flexible lower tooth supported overdenture.
Clinical tests were performed by measuring the soft tissue thickness of superimpose the anterior upper ridge at 2 dots 1 cm and 2 cm on each hand to the midline at time of prosthesis delivery and at 12 months. Also, radiographic evaluations of upper edentulous area estimated at time of prosthesis delivery and at 12 months.
Results: there was non-significant increase in upper mucosa thickness in both groups at both points of measurements. Also, both groups showed radiographic bony changes in maxillary ridge. There was significant increase in maxillary bony changes in Group I in compare to Group II.
Conclusion: it was concluded that there was slight increase in the thickness of soft tissue above the anterior upper ridge in each sequence. More bone resorption allover region of maxilla was observed in Group I, but there was slight decrease in Group II more than Group I.