An implant impression is a negative likeness, or copy in reverse, of the implant and surrounding oral structures. Its purpose is to capture the precise position and orientation of a dental implant within the mouth. This step is necessary for creating an accurate model, which serves as the blueprint for designing and fabricating a custom dental implant restoration, such as a crown, bridge, or denture.
The Critical Role of Implant Impressions
Taking an accurate implant impression is a foundational step for the success and longevity of any dental implant restoration. Precision ensures the final prosthesis fits perfectly, allowing for optimal function in chewing and speaking. It also contributes to natural aesthetics, ensuring the restoration blends seamlessly with existing teeth and soft tissues.
Without an accurate impression, the final restoration may not fit passively, leading to complications like stress on the fixation screw, crestal bone loss, or incomplete seating of the prosthesis. Unlike natural teeth, which have a periodontal ligament allowing for slight discrepancies, implants lack this natural shock absorber, making precise fit even more important. The impression acts as a detailed map, guiding fabrication to ensure the long-term prognosis of the restoration and surrounding bone.
Conventional Impression Techniques
Conventional impression techniques use physical materials to create a mold of the implant site. This process uses impression trays along with specialized impression posts or copings that attach to the implant or abutment. These posts help transfer the exact position and angulation of the implant to the impression material.
Common impression materials include polyvinyl siloxane (PVS) and polyether, both valued for their dimensional stability and ability to reproduce fine details. The procedure involves dispensing a putty-like material into the tray, which is then placed over the teeth and implant components. After a few minutes, the material sets and hardens, capturing a precise negative imprint of the oral structures.
Once the impression is removed, it contains the embedded impression coping, which reflects the implant’s position and orientation. This impression is then sent to a dental laboratory, where a technician pours high-strength stone into the mold to create a 3D model of the patient’s mouth. This stone model serves as the working model for designing and fabricating the custom implant restoration.
Digital Impression Techniques
Modern dentistry uses digital impression techniques, which employ intraoral scanners to create a 3D digital model of the implant and surrounding oral structures. These handheld scanners use light-based technologies to capture detailed images of the patient’s mouth. The images are then processed by specialized software to generate a precise digital representation.
The process involves placing a scan body onto the implant or abutment. The intraoral scanner then captures the unique geometric shape of this scan body, along with the surrounding teeth and soft tissues, to register the implant’s angulation and orientation. This digital data is then directly integrated with computer-aided design/computer-aided manufacturing (CAD/CAM) technology.
Digital impressions offer several advantages, including increased speed and enhanced patient comfort by eliminating the need for traditional impression materials. They also reduce the risk of distortion and shrinkage associated with physical materials, improving accuracy. The immediate feedback from the scanner allows the dental professional to review the scan on a screen and retake sections if needed, streamlining the workflow for restoration design and fabrication.
Patient Experience and Considerations
During an implant impression procedure, patients can expect a straightforward process, whether conventional or digital. Before the impression, good oral hygiene is advised to ensure the cleanest possible environment. With conventional impressions, patients will experience the placement of a tray filled with a soft, putty-like material into their mouth. This material sets within a few minutes, and while not painful, some individuals might feel pressure or a temporary, unpleasant taste.
For digital impressions, a small, wand-like intraoral scanner is moved around the mouth to capture images. Patients might notice a light emitted from the scanner, but there is no physical material or taste involved, which improves comfort, especially for those with a strong gag reflex. The duration for either method is short, usually ranging from 5 to 15 minutes, depending on the number of implants and case complexity. After the procedure, there are no immediate post-procedure considerations, and patients can resume normal activities.