Size 24 to 29.5 fits in primary first molars, size 30 to 35.5 fits in second primary molars and size 36-42 fits in young permanent molar. Select a band by trial and error method if band is loosely fitting select a smaller size and if the band is having lot of resistance to slide circumferentially below middle one third of tooth select a bigger size of band.

Straight loop should be reserved for cases when space loss does not permit use of the curved loop without trimming the tubes. Straight loops have a greater incidence of slipped contact and gingival impingement (resulting in possible space loss) if a child bites on hard foods or objects. The curved loop is the loop of choice for most cases. It’s design prevents the loop from slipping below the contact and impinging on the gingival tissue. The curved loop will better engage the surface of the adjacent tooth, particularly if the tooth it is contacting is only partially erupted.

In the case where the first permanent molar has not erupted yet, and a second primary molar is removed, a distal shoe can be placed subgingivally to guide the eruption of the permanent molar. Radiographic imaging is required to confirm proper placement of the blade of the spacer adjacent to the mesial surface of the unerupted permanent molar. Ideally, the blade should contour and make contact with the mesial surface of the permanent molar. It is acceptable to place the blade in the most distal aspect of the distal root socket of the extracted tooth, if necessary.

Slide the wire in the groove of the cutter and the length of wire you want to cut extend it beyond the centre of groove and cut it.

Once you have a proper fit, crimp the tubes of the space maintainer before removing from the mouth, to firmly secure the wire loop, ensuring the wire is locked into place. After removing from the mouth, make additional circumferential crimps on both tubes to ensure the wire is well secured and no sharp edges exist.