The Rotational Movement of Mandibular 2-Implant Overdentures Reduces Chewing Ability

Objectives: The aim of this study was to investigate how rotation of mandibular implant overdentures (IODs) with 2 ball attachments affects a patient's satisfaction with chewing ability. Methods: Seventy-nine participants were recruited and asked: (1) How satisfied are you with your lower dentures? (100mm VAS), (2) How difficult is it for you to chew your food? (100mm VAS), (3) Do your dentures lift up at the back when you chew? (yes-no question), and (4) How much does this lifting bother you? (100mm VAS). Data on participant characteristics, such as age, gender, period of time wearing the existing denture, height of alveolar ridge, denture shape and the retentive force of the attachments were also gathered. Student t-test and logistic regression were used to analyze mean differences between participants who did (R group) and did not (NR group) report denture rotation. Results: Thirty-seven of 79 participants (47%) were aware of rotational movement with their IODs. They were significantly less satisfied with their chewing ability than those who felt no rotation (69.1mm R group vs. 82.9mm NR group; p=0.01, t-test), and this bothered them (39/100mm). The greater the distance between the tip of the anterior teeth and the anterior denture border, the more the participant was aware of a rotational movement (odds ratio=1.5 vs. NR group; p=0.03). Conclusion: Rotational movement with a mandibular 2-implant overdenture has a negative impact on perceived chewing ability and this can be disturbing to the wearer.