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Dental gypsum DIN EN ISO 6873

5 types and 5 qualities - HINRICHS has the right gypsum

Types and description
The European countries have approved set instructions for dental gypsum.
Type 5 for super hard stone with high expansion are a new category.

DIN EN ISO 6873, which is binding for all manufacturers, classifies the products as follows:

Type 1: 	     Impression Plaster
Type 2:	      Plaster & Articulation Plaster
Type 3:	      Hard Stone
Type 4:	      Super Hard Stone (up to 0.15% expansion)
Type 5:	      Super Hard Stone (up to 0.30% expansion)

Following minimum requirements for     Standard                             Minimum                    Min./Max.         Max. hardening            Min./Max.
the different classes were             consistency                          processing time            hardening time    expansion in %            compressive
stipulated:                            in mm                                in minutes                 in minutes        after 2 hours             strength N/mm2
                                                                                                                                                   after 1 hour
Type 1 Impression Plaster                        80 +/- 4                            1,25                     2,5 / 5,0           0,15
Type 2 Plaster & Articulation Plaster            75 +/- 4                             2,5                    6,0 / 30,0           0,30                    4,0 / 8,0
Type 3 Hard Stone                                30 +/- 3                             3,0                    6,0 / 30,0           0,20                       9,0
Type 4 Super Hard Stone, low exp.                30 +/- 3                             3,0                    6,0 / 30,0           0,15                      20,0
Type 5 Super Hard Stone, high exp.               30 +/- 3                             3,0                    6,0 / 30,0        0,16 - 0,30                  35,0
                                                                                                                                                            35,0

If comparing the data provided for the various gypsum, please ensure compliance with the times stipulated. Binding expansion must be determined 2
hours after, and pressure resistance 1 hour after water-gypsum contact. If other times or measuring units (e.g. Brinell hardness, hardness) are specified,
these are not comparable with the DIN EN ISO 6873 values and will mislead the user. Our quality controls at the plant are in strict compliance with DIN
EN ISO 6873.

Preparations of Impressions

In laboratory practice, problems between the various moulding compounds and gypsum arise time and time again. Since some
moulding compounds have an aggressive reaction towards gypsum, pre-treatment is required in order to prevent, for instance,
efflorescence on the surface of the gypsum model.
We therefore recommend the following measures:

Material                               Alginate                             Polyether                          Hydrocolloids                       Silicones

Properties                             Shrinking will occur as a result of  Hydrophilic properties/ Swells     Pour out immediately,               Stable shape and insensitive
                                       moisture loss. Cannot be stored      if stored for a long time in       otherwise the volume will alter     without a change in volume.
                                       longterm – max. 1 hour; keep         disinfectant.                      considerably.
                                       moist.

Preparation                            Completely remove saliva- and        Remove saliva- and blood           Completely remove                   Remove blood- and saliva
                                       blood residues. Neutralise by        residues under tap water.          saliva- and blood residues          residues under tap water.
                                       immersing in trimmer water or                                           under tap water. Neutralise by
                                       gypsum powder/ Thicken with                                             immersing in trimmer water
                                       Neutralgin.                                                             or gypsum powder, then rinse
                                                                                                               and immerse in 2% potassium
                                                                                                               sulphate solution.

Disinfection                           With conventional                    With conventional disinfectant;    With conventional                   With conventional
Storage                                disinfectant or 1% peracetic acid;   again a risk of swelling – there-  disinfectant or 1% peracetic acid.  disinfectants.
                                       risk of swelling. Rinse under tap    fore disinfect only for a short    Again a risk of swelling.           Cross-linking silicones
                                       water.                               period.                            Rinse under tap water.              can be stored for unlimited
                                       Pour out after a max. of 60 minu-    Good storage stability;            Quickly pour out/gypsum with a      periods; condensation-
                                       tes and protect against drying       relatively insensitive.            short setting time are beneficial;  cross-linked silicones can be
                                       out with moist wipes.                                                   prolonged contact adversely         stored for a limited period.
                                                                                                               affects the surface of the gypsum
                                                                                                               model.

Strictly comply with the manufacturer’s instructions for use when using moulding compounds and disinfectants.

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