Individual Stud Attachments

With the advent of the locator attachment system, there has been a decrease in the use of magnets, ball attachments, and the ERA attachment system. Features such as resiliency, self-alignment^38-40 (making it easy for the patient to align and seat the prosthesis), dual retention (internal and external),^38-40 ease of replacement of the nylon retentive inserts^41,42 and maintenance of oral hygiene,⁴³ lowest vertical profile⁴⁰ (3.17mm for external hexagon implant, 2.5mm for internal connection) (Figure 4), high success rate⁴⁴ and superior clinical performance (compared to ball and bar attachments)⁴⁰ have made the locator attachments very popular among the restorative dentists. The locator attachment system has become the attachment of choice when there is reduced vertical restorative space.²⁸ However, all stud attachments (Locator included) incur a significant reduction in retention when used in association with converging/diverging implants.^45-47 The extended range (Gray, red, orange, or green) locator inserts to correct up to 20° angulation per implant (40° between two implants) have been recommended for non-parallel implants. However, the extended range inserts only provide external retention and also wear faster than the standard range.^48,49

Figure 4. Comparison of vertical dimensions of the locator (left), mini ERA (center), and the ERA (right) attachment system.

Figure 4. Comparison of vertical dimensions of the locator (left), mini ERA (center), and the ERA (right) attachment system.

Picture courtesy of Dr. Cagna

Recently introduced Locator R-Tx removable attachment system (attachment system for removable implant-supported prostheses) (Figure 5) eliminates the limitations associated with conventional locator attachment.⁴⁹ It permits a 50% increase in pivoting capability and up to 30° angle correction per implant as opposed to a maximum of 20° angle correction per implant with the conventional locator attachment system.⁴⁹ In addition to its angle correction capability, several new features have been incorporated to improve its clinical performance.⁴⁹ The success of a removable implant restoration primarily depends on the retentive capacity of its attachment to perform optimally over an extended period of time.

Figure 5. Locator R-Tx attachment system.

Figure 5. Locator R-Tx attachment system.

Picture courtesy of Dr. Massad