Designed with a moderately thick clasp, Counterpoise (below) is ideal for short abutment teeth (less than 3 mm to the marginal ridge). It uses a mesial rest (A), a bracing plate (B), and a separate retentive arm (C).
EsthetiClasp (below) uses a heavier clasp than Counterpoise, with the retentive arm (C) being directly connected to the bracing plate (B) and the mesial rest (A). This design provides the additional strength needed for long saddles (4 or more teeth).
The Saddle-Lock (below) partial uses a light retentive clasp (C), which is protected by a metal housing (D). The abutment must be tall (4+ mm from the marginal ridge to the gingival rest) in order to provide room for the metal housing but the thin clasp easily adapts to deep undercuts on the distal surface. As with the other designs, Saddle-Lock uses a mesial rest (A) and bracing plate (B).
There are also other options for providing an esthetic restoration. ClearClasp (clear flexite clasps) and The Virginia Partial (a flexible band partial) are options available from Armstrong Laboratory.
Counterpoise is a copyright of Armstrong Laboratory, Inc.
EsthetiClasp is a copyright of Austenal, Inc.
Saddle-Lock is a copyright of Saddle Lock Inc.