Selection of the Optimal Attachment System for Implant Overdentures

Attachment system selection depends on a variety of factors that must be identified early in the treatment sequence. These factors include:

1. Trajectory and position of implants: Individual attachments (Locators, ERA, Ball, and Magnets) are often indicated when implants are planned/placed parallel to each other.⁵⁰ When implants have non-parallel trajectories, a bar attachment, Syncone, or the R-Tx attachment system should be selected. Bar attachments are also preferred when implants cannot be placed in ideal locations due to interference with anatomic structures, such as the presence of mental foramen or ridge crest seen in patients with severely resorbed ridges.^51-53

2. Desire for cross arch stabilization: The inherent design of the bar attachment system provides cross arch stabilization.^54,55

3. Decrease in Prosthesis size: When patients require a minimum size of the definitive prosthesis, specifically designed milled bars can be utilized to accomplish the same. ⁵⁶

4. Frequent occurrence of sore spots: Bar attachments are commonly indicated in patients who are xerostomic and/or prone to soft-tissue sore spots as the denture can be entirely bar supported, thereby minimizing impingement on denture bearing tissues. ⁵⁷

5. Poor oral hygiene: Patients who are incapable of maintaining optimal oral hygiene or patients who will not dedicate appropriate time for maintenance of oral hygiene should be cautioned and, at times, denied placement of bar attachments until they commit to an appropriate oral hygiene regimen. ⁴³

6. Restorative space: Minimum restorative space required for implant-supported overdentures with locator attachments is 8.5mm vertically. ²⁹ Implant overdentures supported by bar attachments require a minimum of 12 to 14mm of vertical space.³⁶

7. Ease of fabrication/repair: Removable restorations supported by a bar are more challenging to fabricate and repair than removable restorations supported with individual stud attachments.^31,33,35

8. Opposing arch: It is necessary to identify the opposing arch in the treatment planning process. If a complete denture is planned for the maxillary arch; it would be advised to treatment plan the mandibular implant overdenture with individual stud attachments as opposed to a bar attachment system to avoid excessive forces on the maxillary ridge.³⁷

9. Economics: The cost of fabrication of the bar attachments in contrast to stud abutments will be much higher in most instances.^11,53 However, treatment options should never solely be based on finances.