STRESS DISTRIPUTION OF IMPLANT RETAINED OBTURATORS USING TWO IMPLANT PLACEMENT CONFIGURATIONS FOR MAXILLECTOMY CASES: IN-VITRO STUDY

Introduction: Implant-retained obturators have several advantages over traditional obturators for maxillectomy patients. Appropriate prosthetic design for specific condition after maxillary resection is essential for improvement of retention, stability of implant retained obturator. Objectives: evaluation of peri-implant stress distribution of obturators retained by three implants placed with two different placement configurations.Material and methods: Three implants arranged in linear configuration and other three implants arranged in nonlinear configuration were inserted into two identical epoxy resin maxillary models of completely edentulous unilateral maxillary defect (Brown’s class IIA). 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 strain gauges, the two groups' differences in strain distribution were measured and compared. Using the universal testing machine, bilateral applications of vertical load and oblique load (30o and 45o) of 50 and 100 N were applied in order to assess stress distribution around implants.Results: There was statistically significant difference in strain value between group I (linear configuration) and group II (nonlinear configuration) after application of 30o oblique loading at 50 N and 100 N with p value < 0.0001 as group II exhibited lower strain values.Conclusions: Implant placed with nonlinear configuration showed less strain values than implant placed with linear configuration.