Comparison · Direct restorative and adhesion
Dycal, glass-ionomer liners, MTA or Biodentine: choosing a liner, base or pulp-capping material
In short
For a direct pulp cap on a healthy pulp, a calcium-silicate cement (MTA or Biodentine) is the best-supported choice; a network meta-analysis ranked both above calcium hydroxide. Under a composite on deep dentine without exposure, a thin resin-modified glass ionomer liner seals tubules and bonds to the tooth. Calcium hydroxide remains a valid indirect pulp-capping and lining material where cost and speed matter, placed in a thin layer and covered.
- A liner is a thin coating over dentine near the pulp; a base is a thicker layer that replaces dentine; a pulp cap is a material placed directly on an exposed pulp or on the last layer of dentine over it.
- In a network meta-regression of randomised trials, Biodentine and MTA showed higher direct pulp-capping success than calcium hydroxide, with low certainty of evidence.
- Meta-analysis of direct comparisons found similar success between MTA and Biodentine; Biodentine sets faster and does not discolour the tooth, while grey MTA can.
- Hard-setting calcium hydroxide is soluble over time and forms a porous dentine bridge, which is why it is kept thin and always covered by a sealing restoration.
- Resin-modified glass ionomer liners bond to dentine, release fluoride and cure in a thin layer; they are not intended as pulp-capping materials on an exposed pulp.
The problem: four tubes that all say pulp protection
Deep caries removed, a thin floor of dentine left, maybe a pinpoint of pink. On the shelf: a calcium hydroxide paste, a light-cured glass ionomer liner, a bioactive liner in a syringe, and an MTA or Biodentine kit. All say pulp protection. They are not interchangeable: they differ in what they do to the pulp, how well they seal, how strong they are, and what the evidence supports them for. This comparison sorts them by role and by indication, and lists the products we stock in each class.
Understand: liner, base, cap
A liner is a thin layer over dentine close to the pulp. Its job is to seal tubules, reduce sensitivity and, for some materials, encourage reparative dentine. A base is thicker; it replaces lost dentine, insulates and supports the restoration. A pulp cap is placed either directly on exposed pulp tissue (direct cap) or on the last thin layer of affected dentine over it (indirect cap). The material for a direct cap must be biocompatible in contact with pulp tissue, seal against bacteria, and encourage a dentine bridge; the material for a liner under a composite mostly needs to seal and bond.
Calcium hydroxide
The traditional pulp-capping agent. Its high pH kills bacteria and irritates the pulp into forming reparative dentine. Hard-setting two-paste products (Dycal and its equivalents) and light-cured versions are easy to place. The drawbacks: it dissolves over time, the bridge it forms is porous and often has tunnel defects, and it is too weak to support a restoration on its own. It is kept thin and covered.
Resin-modified glass ionomer liners
Light-cured glass ionomer in a syringe: bonds to dentine, releases fluoride, seals tubules, and cures in a thin layer with low sensitivity to moisture. This is the routine liner under a composite where dentine is thin or sclerotic. It is not a pulp-capping material on an exposed pulp.
Bioactive resin liners
Light-cured resin liners carrying calcium hydroxide or hydroxyapatite. Convenient, fast and radiopaque; the evidence for their use on exposed pulp is weaker than for calcium-silicate cements, and they are best regarded as liners rather than direct capping agents.
Calcium-silicate cements (MTA, Biodentine and their relatives)
Hydraulic cements that set with water, release calcium hydroxide as they set, and form a dense, well-attached dentine bridge. MTA is the original; grey and white forms differ in discolouration risk. Biodentine is a faster-setting dentine substitute that can be used as a base and even as a temporary restoration. Premixed putties and light-cured MTA-type materials exist. These are the materials the evidence supports for direct pulp capping.
What the evidence says
- Evidence. A network meta-regression of randomised trials found Biodentine and MTA had significantly higher direct pulp-capping success than calcium hydroxide, with Biodentine ranked first and MTA second, while noting low certainty of evidence and heterogeneity between trials.
- Evidence. Direct comparisons of MTA and Biodentine pooled in a systematic review showed no statistically significant difference in success; individual trials report Biodentine's faster set and lack of discolouration as practical advantages.
- Evidence. As an indirect pulp-capping agent, a randomised trial comparing Biodentine with light-cured MTA found similar high success at one year.
- Practice. Under a composite without exposure, most clinicians now use a thin resin-modified glass ionomer liner on the deepest dentine only, and rely on the adhesive elsewhere.
Options: the materials we stock
| Class | Stocked examples | Role |
|---|---|---|
| Calcium hydroxide, hard-setting | Dycal Dentin (Dentsply Sirona), Prime-Blend Ultra, Opacal, Cal LC (light-cured, radiopaque) | Indirect pulp capping, thin liner, economical |
| Resin-modified glass ionomer liner | Fusion iSeal LC, Ionoseal, Biner LC, WP Glass Liner | Liner under composite and amalgam; sealing deep dentine |
| Bioactive resin liner | Ultra-Blend Plus, ApaCal Art | Light-cured liner with calcium or hydroxyapatite release |
| Calcium-silicate cement | Biodentine, MTA Plus, RetroMTA, PD MTA White, OrthoMTA | Direct and indirect pulp capping, pulpotomy, perforation repair, root-end filling, apexification |
| Placement instruments | Dycal applicators, single and double ended | Carrying a small amount to the deepest point |
Shop the categories in this guide
Compare: material by indication
| Indication | First choice | Alternative | Notes |
|---|---|---|---|
| Direct pulp cap, small exposure, healthy pulp, bleeding controlled | Biodentine or MTA | Calcium hydroxide covered by a glass ionomer base | Isolation, haemostasis with sterile saline or sodium hypochlorite, then the cap, then a sealing restoration in the same visit where possible |
| Indirect pulp cap over thin affected dentine | Calcium-silicate cement or calcium hydroxide | Resin-modified glass ionomer liner | Leave the last layer of affected dentine; seal |
| Liner under composite, deep dentine, no exposure | Resin-modified glass ionomer liner | Bioactive resin liner | Thin layer on the deepest dentine only; bond the rest |
| Base replacing lost dentine | Biodentine, or glass ionomer | Core build-up composite | Biodentine can be cut back and bonded over after setting |
| Perforation repair, root-end filling | MTA or a bioceramic putty | Biodentine | Moisture is needed for the set |
| Pulpotomy in a primary molar | MTA or Biodentine | Calcium hydroxide (weaker evidence) | Cover with a stainless steel crown where indicated |
Choose a calcium-silicate cement whenever the pulp is exposed or nearly so. Choose a resin-modified glass ionomer liner for the routine deep composite. Keep calcium hydroxide for indirect caps and where cost is the deciding factor, and always cover it.
Technique notes
- Rubber dam before any exposure is touched; bacteria, not the material, decide the outcome.
- Control bleeding with a cotton pellet moistened in saline or diluted sodium hypochlorite; if bleeding does not stop within a few minutes, the pulp is inflamed and a cap is the wrong treatment.
- Place calcium-silicate cements in a layer thick enough to set and seal, then a glass ionomer or resin base, then the restoration; Biodentine can be left as the restoration briefly.
- Keep calcium hydroxide thin and at the deepest point; do not spread it over walls you intend to bond.
- Record the material, the exposure size and the pulp status; review vitality at follow-up.
Recommended products
Calcium hydroxide liners and the instrument that places them:
Glass ionomer and bioactive liners:
Calcium-silicate cements for capping and repair:
Buying advice
Two products cover most days: a resin-modified glass ionomer liner for deep composites and a calcium-silicate cement for exposures. Add Dycal and an applicator if you do many indirect caps at a lower cost per case, and a bioceramic putty if you also repair perforations or place root-end fillings.
Frequently asked questions
Do I still need a liner under every deep composite?
No. With modern adhesives, a liner is placed only where the remaining dentine is thin, roughly within a millimetre or two of the pulp, or where the dentine is sclerotic and sensitive. Elsewhere the adhesive seals the dentine. A liner placed everywhere just reduces the surface available for bonding.
MTA or Biodentine for a pulp cap?
The trials that compared them found similar success. Biodentine sets in about 12 minutes, handles like a thick cement, can be built up as a base and does not stain; MTA has the longer record and is often sold for repairs and root-end fillings. Either is a sound choice; the differences are handling and aesthetics.
Can calcium hydroxide still be used?
Yes, particularly for indirect pulp capping and as a liner where cost matters. Its limitations are solubility, weak mechanical properties and a less predictable bridge than calcium-silicate materials, so it is placed in a thin layer over the deepest point only and covered with a glass ionomer or resin base.
What is the Dycal applicator for?
A fine ball-ended instrument that carries a small amount of mixed calcium hydroxide to the deepest point of the cavity without smearing it over the walls that will be bonded. The same instrument places small amounts of flowable liners.
When is a pulp cap the wrong choice?
When the pulp has signs of irreversible inflammation: lingering pain to cold, spontaneous pain, a large carious exposure with uncontrolled bleeding. Those teeth need pulpotomy or root canal treatment, and a cap delays the diagnosis.
Sources
- Comparative clinical success of direct pulp capping materials: network meta-regression of randomised clinical trialsEvidence
- Efficacy of MTA versus Biodentine as a direct pulp capping material in carious mature permanent teeth: systematic reviewEvidence
- Biodentine versus light-cured MTA as an indirect pulp capping agent: randomised controlled trialEvidence
- Dycal calcium hydroxide liner, Dentsply Sirona product informationManufacturer
