Dental implants can be used to support artificial crowns using one of two main methods: screw retained or cement retained systems. While both methods are used in dental practice, they differ in how the crown is attached and maintained over time.
This article outlines the key differences between these two systems, with a focus on how they affect treatment outcomes, hygiene, and long-term care.
What Are Screw Retained Dental Implant Crowns?
Screw retained implants use a small screw to attach the dental crown directly to the implant fixture. The screw passes through an access hole in the crown, allowing the crown to be seated onto the implant post and fastened securely. This access point is later filled with a tooth-coloured material to maintain a natural appearance.
This method creates a direct, stable connection between the crown and implant. It also allows the crown to be removed easily if adjustments or repairs are needed.
What Are Cement-retained Dental Implant Crowns?
In cement retained systems, the crown is bonded to a connector piece (called an abutment) using dental cement. The abutment is first secured to the implant, and the crown is then permanently fixed onto it. This process is similar to how crowns are placed on natural teeth.
Cement retained crowns do not have a visible access hole, which may offer a smoother surface. However, this method also makes the crown more difficult to remove and may pose challenges in certain clinical situations.
Advantages of Screw Retained Implants
Screw retained systems offer several practical benefits:
Retrievability: The crown can be removed without damage, making it easier to clean, adjust, or repair if needed.
Reduced Risk of Complications: Since no cement is used, there is no risk of excess cement becoming trapped under the gums, a common cause of inflammation and implant-related infections.
Simplified Maintenance: Regular check-ups are easier to manage because the crown can be removed for inspection or cleaning without cutting or breaking it.
Clinical Precision: The screw attachment allows for precise crown positioning and easier correction of bite alignment.
These advantages make screw retained implants a widely preferred option, especially for patients with complex oral conditions or a history of gum disease.
Considerations with Cement Retained Implants
Although cement retained implants can provide a smooth, natural-looking crown surface, they are associated with some limitations:
Difficult to Remove: If the crown needs to be taken off for any reason, it often requires cutting and replacement.
Cement-Related Risks: Any cement that remains beneath the gums may cause irritation, inflammation, or infection if not properly removed.
Limited Access for Hygiene: Since the crown is permanently fixed, it may be harder to monitor and clean around the implant over time.
Due to these factors, cement retained systems are generally used with caution and are not suitable for every clinical situation.
Potential Drawbacks to Consider
Both implant types have considerations that may influence your treatment choice.
Understanding these considerations helps you make an informed decision with your dental team about which approach suits your specific situation.
Screw Retained Considerations:
- Visible access hole: The filled access hole may be noticeable, especially on front teeth
- Complex fabrication: Requires precise laboratory work and may take longer to complete
- However, screw-retained crowns need more space to accommodate the bulkier implant components and as such are dependent on precise placement of the implant fixture.
Cement-retained Considerations:
- Permanent attachment: Crown removal requires cutting and replacement if problems arise
- Cement complications: Excess cement below the gum line can cause inflammation or infection
- In situations where the angulation or depth of placement of the implant in bone is not optimal for accommodation of the bulkier abutments needed for screw-retention, cement-retention being less precise, is flexible enough to allow the fitting of a crown instead of doing additional surgery like bone grafting.
Clinical Decision Factors
The choice between screw and cement retained crowns depends on several factors, including the location of the missing tooth, gum health, bite forces, and the need for long-term access. In many cases, screw retained implants offer more flexibility and control, particularly when maintenance and long-term outcomes are important.
Conclusion
Both screw retained and cement retained crowns serve the same fundamental purpose: to restore function and appearance. However, their design and long-term implications differ significantly.
Screw retained implant crowns provide easier access, fewer cement-related risks, and more predictable maintenance. Cement retained implant crowns may offer aesthetic benefits in select cases but are more difficult to maintain over time. When planning treatment, these differences are carefully weighed to support the best possible outcome for your oral health and lifestyle needs.
