The Use of Ball-clip Attachments with an Implant-supported Primary-secondary Bar Overdenture

T he goals of overdenture attachment for i m p l a n t r e c o n structed edentulous mandibles are to maximize stability and retention of the overdenture and provide shared support of the implants longitudinally, extending their longevity. The attachment system should be simple, predictable, cost-effective, and satisfying to the patient. Many types of attachments have been used for implant overdentures. These include magnets, ball-O-rings, and clips and bars. The most common cause of implant or implant overdenture failure is the higher occurrence of hardware complications, rather than actual direct implant failure. These include the need to repair the retentive clip fractures, acrylic resin fractures, acrylic teeth fractures, and bar fractures, and to replace loose screws. Soft tissue problems include hyperplasia and peri-implant mucositis. Increased maintenance requirements postdelivery can be oral hygiene–related. In addition, there can be opposing denture problems or a need for reline. The overdenture prosthesis must be carefully designed, according to the requirements, to ensure adequate stability and optimum form, contour, esthetics, and patient comfort. Clinical and technical aspects should be considered at the beginning of treatment to (1) select the optimal implant position, (2) establish an adequate number of functional units, (3) select the appropriate retainers, and (4) apply the best technique for framework processing and veneering. Ball-O-ring attachments (Biohorizon O-Rings, Birmingham, Ala) have been widely used because of their low cost, ease of changing attachments, and minimal chair time required. The use of O-rings alone allows for prosthesis movement in 6 directions, but they may require constant replacement of the O-rings from wear and tear of the environmental elements of stress, friction, heat, and swelling. In most cases, connecting the implants with a bar, rather than utilizing them individually (freestanding), is preferred. With the addition of a secondary encapsulator, which is a female attachment inserted into the denture, prosthesis movement can be minimized. Using the encapsulator makes O-ring replacement easier, but failure can still occur because of incorrect O-ring size, improper