A COMPARISON OF THE EFFECT OF DIFFERENT OCCLUSAL FORMS IN MANDIBULAR IMPLANT OVERDENTURES

Statement of problem. Posterior tooth form selection for implant overd entures is made according to personal preference and experience using the concepts of conventional complete denture prosthodontics. Purpose. This study (1) compared the masticatory efficiency of three occlusal forms, 0 degrees, 30 degrees, and lingual contact (lingualized occlusi on), in subjects with mandibular implant overdentures, and (2) determi ned their effects on the implant supporting tissues. Material and meth ods. Eight patients who had four root form implants in the mandibular symphysis area connected with a Hader bar were selected. Maxillary and mandibular dentures were constructed for each patient with interchang eable posterior segments and the three occlusal forms were tested. The masticatory efficiency for each posterior tooth form was assessed wit h objective food tests and a subjective patient preference questionnai re. Periodic evaluation of implant-supporting tissues also was perform ed. Results. Reliability analysis showed that all R-1 coefficients wer e greater than or equal to 0.80 (<0.001), indicating high subject cons istency between multiple chewing efficiency trials. MANOVA analysis in dicated a significant difference in chewing efficiency among the three occlusal forms (p < 0.001). The 0 degree occlusal form was associated with a significantly higher number of chewing strokes compared with 3 0 degrees or lingualized occlusal forms. The different occlusal forms mere not found to have a clinically detrimental effect on the peri-imp lant soft or hard tissues. Conclusion. Chewing efficiency tests and pa tient preference ratings showed that 30 degree teeth and lingual conta ct provided better chewing efficiency than 0 degree teeth. None of the tested occlusal forms showed any clinical or radiographic detrimental effect on the implant-supporting tissues.