Retention of Implant Retained Obturator Using Two Implant Placement Configurations for Maxillectomy Cases: In-Vitro Study

Abstract Background Implant-retained obturators for maxillectomy cases have several advantages over traditional obturators for them. Appropriate prosthetic design for specific condition after maxillary resection is essential for improvement of retention, stability of implant retained obturator. Implant placement configuration for maxillary obturators had several challenges. Objectives Retention evaluation of obturators retained by three implants placed with two different placement configurations. Material and methods Three implants arranged in linear configuration and other arranged in nonlinear configuration were inserted into two identical epoxy resin maxillary models of completely edentulous unilateral maxillary defect (Brown’s class IIb). Two equal sets of twenty-six obturators were constructed; each with different implant placement configuration. Group I include thirteen obturators retained by three implants with linear configuration while Group II include thirteen obturators retained by three implants with nonlinear configuration. Both groups included the same attachment design (non-splinted Ball attachment). Using a cyclic loading machine that served as a dental mastication simulator, each obturator was subjected to 500 tension-compression cycles. Using the universal testing machine, each obturator was removed at a speed of 50 mm/min for the crosshead. To evaluate the initial retention and loss of retention between the two groups, peak load to dislodgement was measured both before and after the cyclic test. Results Nonlinear implant placement configuration for class IIb maxillectomy showed more initial and final retentive force than linear implant placement configuration Also, after cyclic tension-compression test of 500 cycles, all implant-retained obturators lost significant portions of its initial retention but group I (linear configuration) lost a higher percentage of its retention compared to group II (nonlinear configuration). Conclusions non-linear implant placement is more retentive than linear and lost less retention after usage.