Glass ionomer cement is bought in two formats that behave like two different products: a bottle of powder and a bottle of liquid that the clinician proportions by eye, and a capsule that fixes the ratio before the material leaves the box. This guide is written for the person placing the order rather than for the person placing the restoration. It covers which standard now applies, why the powder-to-liquid ratio decides strength and fluoride release, what the order has to state, how capsules and hand-mixed material differ in use, and how many units a practice actually gets through. The mixing pad and instrument wipe is supplied as disposable washcloths, 10 x 13 inch, 500 per case, because hand-mixed cement is the format that generates the most bench waste.
Quick facts
- ISO 9917-1:2007 was withdrawn on 27 May 2025 and replaced by ISO 9917-1:2025, Dentistry — Water-based cements — Part 1: Acid-base cements (corrected version 2025-10); a specification sheet that still cites the 2007 edition is citing a superseded document.
- ISO 9917-1 covers acid-base cements for permanent cementation, lining and restoration, both hand-mixed and encapsulated, and states limits for each property according to whether the cement is a luting agent, a base or liner, or a restorative material.
- ISO 9917-1 explicitly does not cover resin-modified water-based cements; those are covered by ISO 9917-2:2017, which addresses materials that set by a combination of an acid-base reaction and polymerisation.
- Polymer-based restorative materials, including resin luting materials, sit under ISO 4049:2019 — a different document with a different test set, which is why a "cement" order can end up citing three different standards depending on the chemistry.
- The powder-to-liquid ratio is not a mixing preference. Published work links it to physical properties and fluoride release, which is why the manufacturer's ratio is part of the product rather than a suggestion (Dent Mater J 2020).
- A capsule controls the ratio; a bottle does not. That single difference decides how much of the order should be capsules and how much can be hand-mixed.
Which standard applies to the cement being ordered?
Three standards sit behind the word "cement" on a dental order form, and the first step in writing a specification is deciding which one the product falls under.
ISO 9917-1:2025 is the current edition for acid-base water-based cements. Its scope covers "requirements and test methods for acid-base, dental cements intended for permanent cementation, lining and restoration", applies to "both hand-mixed and encapsulated cements for mechanical mixing", and sets "limits for each of the properties according to whether the cement is intended for use as a luting agent, base or liner, restorative material" (ISO 9917-1:2025). The 2007 edition that most catalogues still print was withdrawn in May 2025, so the edition number is now a line item worth checking.
ISO 9917-2:2017 covers the resin-modified family: water-based cements "in which setting is achieved by a combination of an acid-base reaction and polymerization", intended for luting, base or lining, restoration and tooth core build-up (ISO 9917-2:2017).
ISO 4049:2019 covers polymer-based restorative materials, including polymer-based luting materials, and expressly does not cover certain materials outside its scope (ISO 4049:2019). A practice that orders "cement" for luting may therefore be ordering a product that is tested against 9917-1, 9917-2 or 4049, and the test set differs in each case.
| Product family | Standard | Intended uses named in scope | What the order should cite |
|---|---|---|---|
| Conventional glass ionomer (powder/liquid acid-base) | ISO 9917-1:2025 | Permanent cementation, lining, restoration | ISO 9917-1:2025 with the intended use stated |
| Resin-modified glass ionomer | ISO 9917-2:2017 | Luting, base or lining, restoration, core build-up | ISO 9917-2:2017 with the intended use stated |
| Resin-based restorative and luting material | ISO 4049:2019 | Direct and indirect restoration, cementation of restorations and appliances | ISO 4049:2019 |
Why does the powder-to-liquid ratio matter more than the shade?
Because it changes the material. A glass ionomer sets through an acid-base reaction between an ion-leachable glass and a polyacid, and the amount of liquid in the mix controls how much of the glass can react, how much water remains available, and how the set material behaves under load.
Published work on the ratio is consistent on the direction of the effect. A 2020 study in Dental Materials Journal examined how the powder-to-liquid ratio changes physical properties and fluoride release in glass ionomer cements containing pre-reacted glass, and a 2011 study compared the ratio against properties in two restorative glass ionomer cements (Dent Mater J 2020, Acta Odontol Latinoam 2011). Composition-property work makes the same point from the materials side: the glass composition and the liquid composition interact, so a ratio that suits one product does not transfer to another (J Mech Behav Biomed Mater 2015).
Three practical consequences follow for a buyer. First, the ratio belongs to the product, so a practice that switches brands has to re-learn the mixing rather than carry the old habit across. Second, a thicker mix is not a stronger mix in any simple sense: too little liquid produces a stiff material that may not wet the tooth or adapt at the margin, and too much liquid reduces strength and increases solubility. Third, the mixture has to be on the pad for the time the instructions state, because the setting reaction starts when the powder meets the liquid.
That is also the argument for capsules in a busy practice. A capsule removes the ratio from the operator's hands, which removes both the variation between clinicians and the argument about whose mix was right.
What should the Ontario order state?
| Order line | What to write | Why it decides whether the delivery is usable |
|---|---|---|
| Product family and intended use | Acid-base, resin-modified, or resin-based, and whether it is for luting, lining or restoration | The standard and the property limits depend on the intended use |
| Standard and edition | ISO 9917-1:2025, ISO 9917-2:2017 or ISO 4049:2019, with the edition | A 2007 edition citation is a superseded document |
| Format | Powder and liquid bottles, or capsules, with the number per box | The format decides mixing control and the per-dose cost structure |
| Shade | The shade system the practice actually uses, and the shades stocked | Shades are bought in packs, so a partial range creates dead stock |
| Package size | Powder mass, liquid volume, capsule count per box and boxes per case | Case counts and shelf life interact: a large case of a slow-moving shade expires on the shelf |
| Setting and working time | The values from the instructions for the intended use | Chair-side timing is a specification, not a preference |
| Expiry and storage | Expiry date on delivery, and the storage conditions from the instructions | Hand-mixed material with an expired liquid is a mixing variable nobody records |
Two lines in that table get skipped and both cost money. The shade range line is where a practice ends up with six boxes of a shade it uses twice a month, and the storage line is where a liquid that has been kept somewhere warm changes the mix without anyone noticing.
How do capsules and powder-liquid differ in daily use?
| Question | Capsules | Powder and liquid |
|---|---|---|
| Who sets the ratio | The manufacturer, inside the capsule | The clinician, at the pad |
| Consistency between clinicians | Fixed | Varies with technique and habit |
| Waste per dose | A partly used capsule is discarded | Leftover mixed material is discarded; bottles remain |
| Suited to | Luting, small restorations, single-tooth work | Situations needing a modified consistency or a larger quantity |
| Storage | Box with expiry, room temperature per instructions | Two components, each with its own expiry and storage rule |
| Ordering unit | Boxes of capsules, then cases | Bottles, often bought as a powder and liquid pair |
| Main failure mode | Capsule not activated or not mixed long enough | Ratio guessed, or liquid contaminated by dipping the powder scoop |
The last row is the one that shows up in audits of inconsistent results. A powder scoop that has been dipped into the liquid bottle, or a liquid bottle left open, changes the mix in a way that no record captures. Capsules remove that failure mode at the cost of flexibility.
How many units does a practice get through?
The honest answer is that it depends on the procedure mix, so the useful calculation is built from the practice's own numbers rather than from an industry average. Three counts give a defensible monthly figure.
Count the luting procedures per month: crowns, bridges, inlays, orthodontic bands and posts each consume one dose. Count the restorative placements where glass ionomer is the material of choice, including paediatric and non-load-bearing work, at one dose each. Count the lining and base applications, which often use a smaller quantity and may share a dose across two teeth.
A practice with 40 luting procedures, 30 glass ionomer restorations and 25 lining applications per month has roughly 95 doses before any waste. Add the doses lost to retries and to material that set on the pad before it was used, which is why a capsule order is usually planned at 10 to 15 per cent above the counted procedures. The same arithmetic is what makes the case size decision: a case of capsules of a common shade turns over; a case of a rare shade does not.
What does the batch record need?
Glass ionomer is a material with a lot number and an expiry date, and both belong in the record when the material is used in a restorative procedure. The minimum is the product name, the lot, the expiry, the date of use and the tooth or procedure. The reason is not regulatory box-ticking: when a restoration fails early, the first question is whether the material was in date and whether the mix was as specified.
The same record supports the storage question. A practice that keeps powder and liquid in a warm treatment room, or a capsule box on a window sill, has a storage deviation that never appears in a chart until something fails. Writing the storage location into the practice's materials procedure makes the check possible.
Cement is mixed in gloves and cleaned off a pad: nitrile examination gloves, 3.5 mil, 1,000 per case and the washcloth case of 500 cover the consumable side of the same procedure. Practice accounts are opened through the wholesale programme, and the instrument-side consumables that support restorative work sit under sterilization monitoring and the dental compliance hub. Reselling? become a distributor.
Two related pages answer the neighbouring questions: how often clinics restock alginate impression material uses the same par-level arithmetic for a different material, and which dental burs to keep in the drawer sets out a stock plan built from procedure counts.
Set the par level before the next order: the printable materials and lot log carries the product, lot, expiry and date of use on one sheet per operatory.
For a practice that wants the sheet generated from the materials it actually stocks, the log generator on the same page builds it at the size of the tray it sits on.
Where a materials question touches the practice's infection-control documentation, the consultation desk answers in writing, specific to the products and the province, with the clause it relies on cited — no account and no sign-up needed.
Sources
All links checked 23 October 2026.
- ISO 9917-1:2025, Dentistry — Water-based cements — Part 1: Acid-base cements
- ISO 9917-1:2007, the withdrawn edition, still cited by many catalogues
- ISO 9917-2:2017, Dentistry — Water-based cements — Part 2: Resin-modified cements
- ISO 4049:2019, Dentistry — Polymer-based restorative materials
- Powder-to-liquid ratio, physical properties and fluoride release in glass ionomer cements
- Powder-liquid ratio and properties of two restorative glass ionomer cements
- Composition-property relationships for glass ionomer cements
- RCDSO: infection prevention and control standard of practice
- Public Health Ontario: provincial guidance on cleaning, disinfection and sterilization in all health care settings
- CliniEco Medical: dental compliance hub
Related reading
- How often do clinics restock alginate impression material
- Which dental burs to keep in the drawer: a stock plan
- Dental matrix bands in Canada versus the United States: which class applies
Frequently Asked Questions
Which ISO standard applies to glass ionomer cement?
It depends on the chemistry. Conventional acid-base glass ionomer falls under ISO 9917-1:2025, which replaced the 2007 edition on 27 May 2025. Resin-modified glass ionomer falls under ISO 9917-2:2017, and resin-based restorative and luting materials fall under ISO 4049:2019.
How much does the powder-to-liquid ratio change the material?
Enough that published studies treat it as a property variable rather than a mixing preference: it affects physical properties and fluoride release, and the effect differs between products. The ratio stated in the instructions belongs to that product and does not transfer to another brand.
Are capsules better than powder and liquid?
They are more consistent, because the ratio is fixed before the capsule reaches the chair. Powder and liquid allow a modified consistency and a larger quantity, at the cost of a ratio that varies between clinicians and a liquid bottle that can be left open.
How many capsules should a practice order per month?
Count luting procedures, glass ionomer restorations and lining applications, add 10 to 15 per cent for retries and material that sets before use, and order to that figure. The case size then follows the turnover of each shade rather than the discount on the largest case.
Do I need to record the lot number for cement?
Yes, for any material used in a restorative or luting procedure. The product, lot, expiry, date of use and the tooth or procedure are the minimum, and they answer the first questions asked when a restoration fails early.
Does the standard edition number matter on a purchase order?
It does, because a specification citing a withdrawn edition is citing a document that no longer states the current requirements. ISO 9917-1:2007 was withdrawn in May 2025, so an order written today should cite ISO 9917-1:2025.
CliniEco Medical supplies infection-control and sterilization consumables in Canada under MDEL #35334. This article describes published standards and purchasing practice and is not clinical advice; confirm mixing ratios, setting times and storage conditions against the instructions supplied with the product in use.
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