Manufacturing and Quality Technology

A specification is only worth the test behind it. This page sets out the manufacturing route for each line, the in-process controls that hold the specification, and the standard each measurement follows — so that when your auditor or your customer asks where a number came from, the answer is a method and a record rather than a catalogue.

Zirconia: Powder to Sintered Blank

• Powder specification — yttria content, particle size distribution and impurity limits are specified on receipt. Yttria content sets the phase balance, and the phase balance sets both strength and translucency; it is the single most important incoming control.
• Pressing and pre-sintering — the powder is compacted and pre-sintered to a controlled density. This is the step that fixes the shrinkage factor, so density uniformity across the puck determines whether a large blank mills to tolerance at its outer edge.
• Machining to dimension — blanks are ground to the specified diameter, thickness and step geometry. Diameter tolerance and step concentricity are measured per batch.
• Verification — flexural strength per ISO 6872, density by the Archimedes method, yttria content by XRF, and the linear shrinkage factor measured on a sintered test specimen from the same batch.

PMMA: Polymerisation and Residual Monomer

PMMA blanks are produced by controlled polymerisation and then machined to dimension. The two figures that determine clinical behaviour are flexural strength and residual monomer content — the latter drives both biocompatibility and long-term colour stability. Both are measured per lot, and the residual monomer figure is reported on the certificate of analysis rather than held internally.

Wax: Consistency in the Billet

Milling wax is cast into a billet and machined, which gives a uniformly dense block without the internal voids a poured pattern can carry. Melting point, linear shrinkage and ash content are tested per batch. Ash content is measured by burnout of a weighed sample and residue weighing — a low figure is the difference between a clean casting and porosity you will spend a day tracing.

Gypsum: Calcination and Expansion Control

Dental stone is produced by calcining high-purity gypsum under controlled temperature and pressure. Expansion is controlled through the calcination parameters and, where the grade requires it, through the addition of a setting regulator. Setting expansion, setting time and compressive strength are tested per lot to the ISO 6873 method, and the water-to-powder ratio that reproduces those figures in your laboratory is stated on the packaging.

Standards Reference

What Ships With Each Order

• Certificate of analysis per lot, quoting the measured values against the specification — not the nominal range.
• Lot traceability from the finished blank back to the incoming powder or raw material lot.
• Technical data sheet per product line, including the processing parameters the figures assume.
• Declaration of conformity for CE-marked products, and establishment registration details for FDA purposes.
• Safety data sheets where the material classification requires one.

Audit and Documentation Requests

We will support a supplier audit and provide the quality documentation a laboratory, a distributor or a notified body requires: quality manual extracts, certificate scope, test reports and lot records for a nominated order. Tell us the standard you are being assessed against and we will send the matching document pack rather than everything we hold.