Gingival Mask on the Working Model — Why It's Too Often Overlooked

A gingival mask is a thin layer of pink silicone applied around the dies on a working model. Its purpose is to replicate the position and shape of the gingiva at the tooth's cervical margin. Without it, the technician works without visibility of the cervical relationship – unaware of how the restoration will interact with soft tissue.

What is a gingival mask and what does it simulate?

A gingival mask replicates three things: the position of the gingival margin, the shape of the interdental papillae, and the emergence profile in the subgingival area. None of this information is available from a gypsum model without a mask, nor from a digital scan without a virtual gingiva.

In laboratory practice, the mask allows evaluation of:

• whether the cervical part of the restoration is not too convex (risk of gingivitis),
• whether the interproximal contact is in the correct position relative to the papilla,
• whether the point contact of the crown with the adjacent tooth does not impinge on the papilla area,
• whether the pontic shape of the bridge promotes hygiene.

Without a mask, an aesthetic restoration can be fabricated that, after cementation, causes inflammation – because the technician had no way to check the emergence profile.

When is a mask essential, and when is it unnecessary?

The simplest situation: supragingival margin, no pontic. The mask provides no additional information then.

Materials and application protocol

At deltalabs., we use A-silicone impression materials with Shore A hardness 20–30 – soft enough to be peeled off when removing the die, yet hard enough not to deform under the weight of the restoration.

Application protocol:

1. Dies on the model are clean and dry.
2. Apply silicone around the die – not on the die – using a thin cannula.
3. Setting time: 2–4 min depending on laboratory temperature (norm: 21–23°C).
4. After setting: check elasticity and accuracy of papilla replication.
5. Inspection: the mask must not cover the margin line – the preparation line must be visible.

Most commonly used materials: Zhermack Gingifast Elastic, Erkodent Erkoflex Gingi, Bredent Gingiva Soft. They primarily differ in base paste consistency and setting time.

Most common errors and their consequences

Mask too thick in the cervical region. The technician fabricates a restoration with excessive space on the gingival side – the restoration is too concave at the cervical margin; bacterial niches form after cementation.

Mask applied on the margin line. Obscured preparation line – the technician cannot precisely see the margin, risk of leakage at the cement-tooth interface.

Omitting the mask for a pontic. The technician does not evaluate how the pontic adapts to the ridge – after delivery, the clinician faces hygiene and aesthetic issues.

Mask too hard. The die cannot be removed without damaging the model. The restoration must be fabricated without removing the die – loss of control over the margin.