Tips From Our Readers
- Conventional implant impressions can be made with an open tray (pick-up) or closed tray (transfer) technique,1,2 with the open tray technique recommended for complete-arch implant impression because of its greater accuracy.3 However, stabilization of the impression copings is essential to prevent micromovement when it is detached from the implant fixture or during placement of the implant laboratory analog.4 Rigid impression copings are essential for the accurate transfer of their 3D position to the definitive cast.
- An accurate implant impression is essential for a successful implant restoration, with various impression techniques being suggested.1 The open tray (pick-up) impression technique has been recommended over the closed tray impression technique for improved accuracy,2 although splinting the open tray impression copings is essential to prevent micromovement and for accurate 3D transfer of the implant locations to the definitive cast.3 Splinting can be achieved in various ways,3,4 including with dental floss and autopolymerizing resin or composite resin.
- The posterior palatal seal (PPS) area plays a critical role in the retention of maxillary complete dentures and is often missed by the clinician.1,2 The PPS area is defined by the Glossary of Prosthodontic Terms3 as “the soft tissue area limited posteriorly by the distal demarcation of the movable and nonmovable tissues of the soft palate and anteriorly by the junction of the hard and soft palates on which pressure, within physiologic limits, can be placed; this seal can be applied by a removable complete denture to aid in its retention.” Various techniques have been proposed to record the PPS area.
- The most significant step in fabricating an accurate implant prosthesis is to transfer the precise 3D intraoral location of the implants to the definitive cast.1 Various impression techniques have been described to achieve the necessary accuracy.2 The open tray impression3 has been widely used; however, translation and rotation of these transfer impression copings may occur when the copings are detached from the implant fixture and during placement of the implant analog.4 Lee et al5 concluded in their systematic review that splinting transfer impression copings produced an accurate definitive cast and prevented micromovement of the impression copings.