Your Go-To Guide For Cementation Of All Types Of Prosthesis (Part 1)

Cementation is the final step of indirect restorations which, usually, we do not take very seriously – until the patient comes back with a dislodged crown repeatedly and we don’t understand where we went wrong! There are two objectives for cementation or luting 1 -

• to help retain the restoration in place and
• for a good marginal adaptation and seal.

If you are one of the many who only use GIC in their clinic, then take a look at various cements available along with their leading brand names, primary advantages & disadvantages, indications with literature supported recommendations and you will be in for a pleasant surprise!

Table 1. Overview of Cements 1,2

Table 2. Indications Chart – Cement Recommendations 2,3,4

1. Composite-resin cement should be used -

• For Maryland bridges
• If enough mechanical retention is not available (preparation height <3mm)

Zinc phosphate cements are not recommended for vital tooth preparations because of their acidic nature. 2. Composite-resin cement should be used -

• If aesthetic and wear resistance needs are assessed and GI-based cements will be insufficient and do not complement the restoration.
• If enough mechanical retention is not available (preparation height <3mm)

3. For most composite-resin cements, with the exception of some self-etching-based systems (i.e., RelyX Unicem), typically more work and effort is needed than for metal-based restorations that have sufficient built in retention. It also may increase the potential for patient sensitivity and difficulty in clean up and so must be handled with care. 4. Restorations made of ceramic mat­erials must be preferably etched with hydrofluoric acid, silanated with silane coupling agent and then bonded to tooth structures. 5. Light-cure only systems are preferred to maximize potential for color stability. Self-cure systems or light-curable “base” components from dual-cure systems have greater potential for color change over time. 6. Zinc phosphate often is the cement of choice for final cementation of an implant restoration. GIC is not used in implant restorations because it is less retentive on the metallic abutment compared to its strong chemical bond on tooth. Other cements used for implant restorations - a. Polycarboxylate cement - It is used when -

• multiple splinted abutments are present,
• if no cantilevers or significant offset loads are present, and a “soft access” cement is desired,
• as a stronger provisional cement for the transitional prosthesis or individual acrylic transitional crown when zinc oxide eugenol appears insufficient.

b. Composite resin cement - It is used -

• to cement a post into an implant body to serve as an abutment for a cemented prosthesis
• when the abutment post is too short for adequate retention and prosthesis removal is not planned at a later date.

Special note- Cementation of provisional/transitional prosthesis.

Temporary crowns in conventional FPD or implant restorations are usually made of acrylic or composite. They are cemented with zinc oxide eugenol/non eugenol cements. Eugenol cements are indicated for relief of pulpal sensitivity. Non eugenol cements are used where subsequent reline and re-margination procedures maybe required or when final cementation is to be done with resin cement. This is because eugenol may inhibit the setting of the acrylic and resin when it is in unset state.

Table 3. Provisional cements

Here, we conclude part 1 of this guide. Stay tuned for part 2 where we will discuss cementation protocols for different types of prostheses and special clinical tips & tricks!

How to select a luting cement clinically

Cement selection begins with four questions: what is the restoration made from, how retentive is the preparation, can the field be isolated predictably and is adhesive bonding required for strength or retention? The answer should then be checked against the restoration and cement manufacturers’ current instructions.

Material–cement compatibility

• Conventional metal and high-strength ceramic restorations: a retentive preparation may permit conventional or self-adhesive luting, depending on the clinical situation.
• Glass ceramics and minimally retentive restorations: these frequently depend on adhesive resin cementation and material-specific surface conditioning.
• Zirconia: avoid treating it as a silica-based glass ceramic; contamination control and a zirconia-compatible primer or cement chemistry may be relevant.
• Implant crowns: consider retrievability, margin location, emergence profile and the ability to remove all residual cement.

Selection checklist

Assess retention and resistance form, remaining tooth structure, pulpal proximity, margin position, moisture control, restoration thickness and translucency, working time and cleanup. Cement film thickness cannot compensate for an inaccurate restoration.

Next, use the step-by-step clinical cementation protocol and review implant residual-cement risk.

Frequently asked questions

Can one cement be used for every crown?

No. Restorative material, preparation design, isolation and bonding requirements change the indication.

When is adhesive resin cement especially important?

It is commonly important for low-retention preparations, veneers and restorations whose strength or retention depends on bonding.

Are self-adhesive resin cements identical to adhesive resin systems?

No. Their conditioning steps, bond performance and indications differ.

Can zirconia be etched like lithium disilicate?

No. Zirconia is not a silica-based glass ceramic and requires a different surface-treatment strategy.

What is the most important implant-cement consideration?

Use a design and delivery protocol that permits complete detection and removal of excess cement.