Modified HAAS (HSS1)
The modified HAAS is based on the indications of Dr. Jean-Noël Lavallée, from the International Dental Institute. This appliance exerts even pressure on the bone part of the upper maxillary and on the posterior teeth. Acrylic pads are fitted on the teeth to create more space for the occlusion without any adverse effects on the lower maxillary.
A brightly-coloured arrow is embedded in each appliance. The palatal part of these appliances is coated in acrylic. Therefore, it is simpler to determine the direction of activation after placement of the appliance.