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Patients with conventional complete dentures experience a significant greater impact on daily life and social situations due to the dentures, than patients with implant-retained over-dentures (Melas, F. et al. 2001). The conventional delayed loading protocol of implants placed to retain overdentures in the edentulous mandible has gradually changed during the last years. It is now clinical documented that immediate loading of implants with an over-denture in the edentulous mandible is possible without compromising the survival rate of the implants. Even the necessary number of placed implants in the inter-foraminal area to accomplish satisfactory clinical results with immediate loading is a matter of discussion. (Røynesdal, Anne-K. et al 2001, Brånemark, P-I et al. 1999, Szmukler-Moncler, S. et al. 2000, Chiapasco, M. et al. 2001). Critical clinical variables are 1) critical limit of micromovements during osseointegration 2) Implant length 3) Implant surface 4) engagement of inferior cortical mandibular border 5) retaining device.
The advantages of immediate loading are reduced treatment time and expenses.
In general all patients with a conventional full lower denture should be considered for this treatment.
Preoperative clinical and radiographic examination include lateral/cephalometric and orthopantomographic radiographs and a clinical evaluation of the intermaxillary relationship and the inclination of the residual alveolar process.
The orthopantomographic radiograph (corrected for the magnification factor) is necessary to evaluate the residual height of mandible in the inter-foraminal area, as well as the supposed exit of the mental nerve. Due to pronounced mandibular atrophy the mental foramen may not be visible, meaning that the mental nerve is emerging on top or lingually to the top of the residual crest.
The lateral radiograph is used to assess the lingual inclination and the width of the residual ridge in the sagittal center of mandible.
The radiographs also give an impression of residual spongy bone between the vestibular and lingual cortical bone
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