Roughening acrylic teeth
Roughening acrylic teeth
The contact surface is roughened to achieve adequate retention between the acrylic tooth and the denture base acrylic. This can be done with special groove or retention milling cutters or fine tungsten burs or by sandblasting. The following simple rules should be observed when sandblasting acrylic teeth:
- Reduce pressure to 1-2 bar.
- Select a fine, 50 µm blasting medium.
- Reduce the amount of blasting if there is an option on the device.
- Always blast vertically onto the surface to be roughened.
integral® tooth line
Juvenile tooth mould (canine tips, incisal edges, cusp tips)
With prefabricated teeth, the dental technician should be able to use the entire range of design options with regard to age-appropriate and function-appropriate design. This is only possible with juvenile teeth through targeted grinding in the articulator, because grinding, like natural teeth do, makes more sense than applying substance. The functional facets adjust by themselves, taking into account the occlusion concepts, and have a special aesthetic effect.
Do the steep cusp inclination of the integral® cause irritation, especially in older patients?
After many years of experience, this is hardly to be expected. According to MDT Polz the cusp inclination is not as steep as the first impression suggests. Due to the simple tooth-to-tooth relationship, a contact relationship in the centric can easily be achieved without “locking in” the patient. The occlusal surfaces have a high degree of masticating effectiveness and require less masticating force than it is on average with flat-cusp teeth, which protects the tegument.
A certain presence of cusp substance is necessary for a patient-friendly design of the eccentric / dynamic types of occlusion. With targeted grinding measures, the integral® posterior tooth can be adapted to all types of occlusion and degrees of abrasion in a very short time without losing its centric position.
CBI - mould classification
The design of the integral® anteriors is based on extensive studies by the Free University of Berlin and clearly has the characteristics of natural teeth in terms of mould and size. With the CBI® system it is easily possible to produce a natural looking denture. The “classic tooth moulds” are often products of imagination and their moulds are not sufficiently based on nature. They are therefore very easy to recognise in the mouth as denture teeth and are less aesthetically pleasing.
Tooth neck design
When designing the "red aesthetics", the impression should be that the tooth has grown out of the gingiva. Due to the angulation in the tooth neck area, the artificial tooth can be modeled into the gingiva according to age. The technician is given the opportunity to adapt the tooth to the actual biological conditions depending on the modelation. The tooth is also better anchored in the base material.
Lingualised set-up acc. to Gerber
Absolutely yes. The first premolars show a long laterotrusion facet and contact relationships as required by Gerber. The A-contacts (buccal cusp contacts) are abandoned on the other posterior teeth. The centric / static occlusion is very stable via the palatal cusp support and can be varied as required with tooth-guided eccentric / dynamic lower jaw movements.
Polystar® Selection & EDITION
For fast working
Why is the Polystar Selection posterior a tooth for fast working?
The Polsytar Selection posterior is a tooth for fast working because
- it can be set-up in the lower jaw as if on rails thanks to its approximal fit. The convex and concave approximal contours of the lower posterior teeth interlock like gears.
- the lower lingual surfaces have a straight contour so that a sagittal orientation is always present during the set-up.
- there is very little need to grind in occlusal (see cusp facets of the adult tooth ”).
- it is swiftly ground in basal (see hollow tooth base) because it is the tooth with grip (see basal groove from mesial to distal).
Low cusp inclination
Why does the Polystar Selection posterior tooth have cusp facets and appear so flat?
This tooth is designed for the prosthetic restoration of adult teeth. Due to the physiological sliding of the antagonists on top of each other when masticating and swallowing (attrition), the “adult tooth” no longer has any juvenile cusps. The pathways characteristic of the respective masticating system leave a typical pattern in the form of cusp facets. The cusps are correspondingly flat compared to a juvenile tooth. These have been inserted into the masticating surface of the Polystar Selection posterior tooth using average values, so that only a minimum of grinding is required. Because the centric stops lie on convex contact areas and the eccentric movement paths for the medio, latero- and protrusion lie on concave “facets”, the centric stops are retained. As a result, the bite height is retained when the eccentric movements are grinded in.
Age-appropriate occlusal surface
Why is the Polystar Selection n o t an abraded tooth?
Abraded teeth are characterised by flat and / or simple convex inner and outer cusp inclinations. In contrast, the Polystar Selection posterior has convex centric contact areas and concave, average-value aligned extrusion paths. The centric stops remain permanently supportive even after grinding in according to the relief, the bite height is guaranteed. In addition, convex occlusal ridges ensure a high shearing ability, the forces are directed in the punctiform spectrum on the alveolar ridge. This protects the denture base. These features are a novelty in the field of pre-fabricated tooth design.
As already mentioned, the Polystar Selection posterior is not a fully anatomically designed tooth. The Polystar Selection posterior, on the other hand, takes into account the physiological movements of the lower jaw of an adult dentition in midlife through convex and concave cusps. The integral® can also be used for young or very well preserved residual dentition situations by specifically grinding in. The cusp facets of the Polystar Selection posterior, on the other hand, are in principle already “pre-ground” to an average-value, so a certain amount of “cusp substance” as in the integral® is no longer present.
Tooth neck contour - modeling reserve
Why does the Polystar Selection posterior tooth have such a long and, above all, clearly contoured tooth neck?
Every tooth has a tooth neck that is visible differently depending on age and the gingival contours. This is a matter of course for anterior teeth, and now also for posteriors, as was done with the integral®. Furthermore, in the case of severely atrophied alveolar ridges, it is aesthetically disadvantageous if no neck can be seen, since the tooth crown protruding freely into the oral cavity - in this case the tooth crown of the replacement tooth - otherwise looks like a "stump" on the denture acrylic. Another reason for lengthening the neck of the tooth was to achieve the most aesthetic coverage possible for anchors, attachments, etc. with the replacement tooth placed in front of them. This is only possible with a clearly contoured and, above all, longer tooth neck. Keep in mind that it is easier to grind a tooth than to add something on.
PSG - basal groove
What is the purpose of the basal mesial to distal groove of the Polystar Selection?
It prevents the tooth from twisting and tilting, so that time-consuming position corrections are minimised. With this, Merz Dental is reacting to the increasing use of modern, hard set-up waxes, in which the mentioned "tooth shifting" occurs due to the material.
Clear and stable fixation while setting up the tooth.
Tilt-free and twist-free set-up in wax, improved dimensional accuracy. Before, during and after the wax try-in, easy repositioning if a tooth has broken away during the wax try-in.