Interproximal Relief and Complete Marginal Seating

In natural dentition, there is microscopic clearance or passive contact between teeth when they are in rest position, which is called Interproximal Relief (IR)*, and when a crown is fabricated, it is necessary to adjust the crown on the proximal contact surfaces to restore IR, and to achieve complete marginal seating for patient comfort and functionality.

The following references to scientific literature illustrate the need for proper interproximal adjustment:

 

Spaces of at least 0.0005-in. (0.0127mm) may exist naturally between teeth in 80%-90% of the proximal contacts.

-P.A.Boice 1987

The fixed partial denture be adjusted until 0.0005-in. shim stock will pass through proximating contacts with very slight resistance.

-W.V. Campagni 1984

Observed spaces ranging from 3 to 21 microns between adjacent teeth at rest.

-K. Kasahara 2000

Small spaces occur between natural teeth. Most of the authors recommend checking the proximal contact with dental floss, and floss does not properly detect these spaces.

-J.T. Lindquist 1951

The contact should not be so tight as to cause wedging of the teeth.

-W.W. Howard 1981

The properly restored proximal contact should be passive contact or microscopic clearance that relieves pressure between the proximal contact surfaces of indirect restorations and adjacent teeth. The relief of pressure is referred as interproximal relief (IR).

-D.S. Kim 2007

 

The following figures are an example of a step-by-step procedure using the ContacEZ Restorative Strip System to achieve complete marginal seating for a new crown.

  Fig.1  A newly fabricated crown is placed on the abutment of tooth #23 and the proximal contact is adjusted by using the fine diamond Black Strip while the crown is held by a finger.

Fig.1
A newly fabricated crown is placed on the abutment of tooth #23 and the proximal contact is adjusted by using the fine diamond Black Strip while the crown is held by a finger.

  Fig. 2  The crown is cemented while a PineStick secures the crown in place.

Fig. 2
The crown is cemented while a PineStick secures the crown in place.

  Fig. 3  Using the serrated White Strip, the remnant cement trapped in the interproximal space is cut and removed.

Fig. 3
Using the serrated White Strip, the remnant cement trapped in the interproximal space is cut and removed.

  Fig.4  The finest diamond Gray Strip is used to polish the proximal surfaces of the crown to its natural texture and to confirm Interproximal relief.

Fig.4
The finest diamond Gray Strip is used to polish the proximal surfaces of the crown to its natural texture and to confirm Interproximal relief.

  Fig.5  The proximal contact between crown #22 and resin tooth #21 of the lower partial denture is adjusted using Black Diamond Strips until light resistance is felt.

Fig.5
The proximal contact between crown #22 and resin tooth #21 of the lower partial denture is adjusted using Black Diamond Strips until light resistance is felt.