A note on Tofflemire matrix retainers

Something that I learned recently about tofflemire retainers. There are two types of Tofflemire retainers: Universal and contra-angled (Figure 1). The universal retainer "U" loop is perpendicular to the long axis of the retainer. The contra angled is intuitively at an offset angle to the long axis of the retainer. When the band is tightened onto the universal retainer it will sit parallel to the retainer. When the band is tightened onto the contra-angled retainer, the retainer will be angled occlusally.

Figure 1

The universal retainer is for cases when the retainer sits to the buccal of the tooth being restored ("Classic technique"). Contra-angled retainers are used when the buccal tooth structure has been lost and the operator wishes to position the retainer on the lingual aspect. The offset angle of the retainer is designed to allow the retainer to sit over the incisal edges. If a universal retainer is used it will sit parallel to the occlusal plane and the incisors will interfere with the seating of the retainer and band.