Prosthetic Treatment
An implant restoration can be removable, hybrid-retained, or fixed, depending on the specific needs of the patient and the clinical situation. With various techniques and options available, it's essential to carefully evaluate the patient’s requirements and the suitability of the solution before proceeding with the final restoration.
Restorative solutions are available for a wide range of cases, from single tooth replacements to bridges and full-arch restorations. The concept of prosthetically-driven implant treatment is becoming increasingly popular, where the restoration is planned from the outset. This approach ensures that the design of the implant and restoration facilitates easy cleaning, promoting optimal oral health by allowing effective plaque removal.
Osseointegrated implants may be restored using fixed implant-retained prostheses or removable implant-supported overdentures. Fixed implant-retained options include single crowns, fixed bridges, and full-arch prostheses.
Full-Arch Fixed and Removable Implant-Supported Prostheses:
Single crowns and bridges can be either screw-retained or cement-retained, both showing similar clinical outcomes (Lemos et al., 2016; Sherif et al., 2014). Screw-retained restorations are often preferred due to their ease of retrieval and absence of excess cement. However, screw-retained crowns may present challenges, such as the potential for weakening the crown due to the screw access hole, and the risk of losing the filling material. They also require precise passive fit and can be prone to screw-related mechanical issues.
One aesthetic drawback of screw-retained crowns occurs when the screw access hole exits on the labial (visible) side of the crown, which can be problematic in terms of appearance.
Cement-retained restorations, on the other hand, avoid this aesthetic issue by eliminating the need for a visible access hole, making them particularly useful when the screw access would emerge on the front side of the crown. However, cement-retained restorations carry biological risks, such as inflammation caused by residual excess cement, and can be more challenging to retrieve if needed.
To address these concerns, angled screw systems have been developed, which allow the screw access hole to be shifted to a less visible, palatal location. These systems provide a reliable and retrievable alternative to cement-retained crowns (Greer et al., 2017).
The European Association for Osseointegration (EAO) provides the following clinical guidelines for retention methods in implant reconstructions (Gotfredsen et al., 2012):
- For single crowns, both screw-retained and cement-retained methods are acceptable.
- When using cement-retained restorations, meticulous removal of excess cement is critical to avoid biological complications.
- For larger reconstructions, such as partial or full-arch fixed prostheses, screw retention is recommended.
Materials and design options
A variety of materials are used to fabricate fixed implant superstructures, including porcelain fused to metal, gold frameworks, acrylic teeth, and all-ceramic restorations using zirconia frameworks. Abutments can be either prefabricated or custom-made, with different angulation options to accommodate specific clinical needs.
To ensure accurate implant restoration, precise impressions of the implants are critical. Bhakta et al. (2011) provide detailed protocols for taking accurate impressions using both closed-tray and open-tray techniques. They also recommend the use of verification jigs to confirm the accuracy of the implant positions.
Additionally, periapical radiographs can be utilised to verify the proper seating of impression copings and abutments, ensuring the correct positioning before proceeding with the final restoration.
We would like to acknowledge Dr. Manraj Kalsi for his insights and contributions to this page