Aim of the study: This study was conducted to assess and compare the effect of extracoronal OT CAP, telescopic crown and magnetic attachments in long span bilateral distal extension cases. Case evaluation: included patient satisfaction, clinical evaluation and radiographic evaluation. Clinical evaluation was performed using plaque index , gingival index , probing depth and periotest.
Materials and Methods: Thirty partially edentulous male patients (age ranging from 50-60 years) having Kennedy class I lower ridges with lower first premolar as last abutment were selected to this study .Removable partial dentures were constructed following the same technique, and using the same materials. All dentures were designed with combined denture bases, lingual bar as major connector .According the attachment type used to retain removable partial denture., patients were divided into three groups: Group I, received removable partial dentures retained by extracoronal OT CAP attachment (Rhein 83, Italy), Group II: received removable partial dentures retained by telescopic crowns exhibiting 10-12 degrees occlusal taper and Group III: received removable partial dentures retained by magnetic attachments (Dyna Magnet System, Holland) .Follow up visits were scheduled at time of denture insertion, six, twelve and eighteen months after denture insertion for inspection of the prosthesis and collection of the data. Case evaluation included patient satisfaction, clinical evaluation of the supporting abutments, which included recording of the gingival index and the clinical attachment level, abutment mobility (using periotest), as well as radiographic evaluation.Radiographs were performed for assessment of bone height mesial and distal to the abutments by serial standardized periapical radiographs made by long cone paralleling technique.
Results: In general, patients were satisfied with the appearance, fit, stability, retention and function of their dentures. They experienced an improvement in their chewing ability and esthetics mainly in group III. There was a slight gradual increase in the gingival index scores, clinical attachment level values throughout the follow up period, in all three groups. However, there were no statistically significant differences between the three groups clinically. Regarding abutment mobility, no statistically significant difference was observed in the mean values of the periotest scores in the three groups along the follow up period. comparing the three studied groups although telescopic attachment retained RPD (Group II )showed the highest mean values and magnetic attachment retained RPD (Group III ) showed the least mean values of the periotest scores during the follow up period , there were no statistically significant differences the studied Groups. There was a statistically significant decrease in crestal bone height around the abutments, telescopic attachment retainer showed the statistically significantly highest crestal bone loss around the abutment, while the magnetic attachment retainer that showed the lowest crestal bone loss.
Conclusions: Telescopic retainers distribute more stresses on the abutments more than extracoronal and magnetic attachments. Magnetic attachment is considered minimal invasive procedure as it reduces only one abutment in comparison to two abutments in cases of extracoronal and telescopic attachments.