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The new Dentaurum hyrax® neo By Terry Whitty
Figure 1. Walter Coffin’s removable expander with piano wire.
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hree maxillary expansion modalities exist today: Rapid Maxillary Expansion; Slow Maxillary Expansion; and Surgically Assisted Expansion. Dr John Mew, an English dentist and an advocate of “orthotrophics”, argued semi-rapid expansion is also a valid treatment as well, so this would sit in between Rapid and Slow. All of these modalities have their advantages and disadvantages and also their fair share of controversy. However, commonly, the practitioner will select the treatment based on experience, the patient’s age and the type of malocclusion. Slow expansion has been attributed to Walter Coffin and a removable device was described by him in 1877 using a piece of piano wire in a vulcanite plate (Figure 2). Rapid Maxillary Expansion was first described by Emerson Angell in 1860 and later made popular by Haas. Originally it was used to reduce the narrowness of the maxilla but in fact, it has an effect on 10 bones of the face and head. Users of this technique believe that minimum dental movement, or tipping, is involved and most of the movement is skeletal.
Figure 2. Angell’s rapid expansion device. When heavy, rapid forces are transferred to the posterior teeth in the correct way, the forces are transferred to the sutures. When this force is beyond that needed for tooth movement and sutural separation, the sites will open up and the teeth will only move minimally within the supporting bone. There is compression of the periodontal ligament, slight bending of the alveolar bone and tipping of anchor teeth before separation of the mid-palatal sutures and separation of the other maxillary sutures. How fast this should occur again is in debate with some cautioning 1mm per week is the maximum, whereas others will take the more aggressive approach. Appliances for rapid expansion are generally threefold: the HYRAX appliance, the Bonded RME and the HAAS appliance. The hyrax® is actually a trademark of the Dentaurum company of Germany and an anagram for HYgenic RApid eXpander. Of course, many companies have copied the device over the years and the word is used generically for any fixed skeletenised appliance connected to two or 4 bands.
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a. Walter Box b. Walter Casket c. Walter Mitty d. Walter Coffin Question 2. The first description of Rapid Expansion was by: a. Emerson Angell b. Lake Angell c. Palmer Angell d. Edward Angel Question 3. The HAAS expander consists of: a. A removable device with Adams clasps and midline screw. b. A fixed appliance attached to orthodontic bands and a large acrylic button with a midline screw. c. A wire “W” framework attached to bands. d. A piston screw device for a single tooth. Question 4. The average correct rate a Rapad Maxillary Expansion Device should be adjusted is: a. 2mm a week b. 1 mm a week c. 5 mm a week d. Still in debate Question 5. The hyrax neo screw: a. Has a lower profile than its predecessor b. Can wind in 4 directions c. Has a maximum expansion of 2mm d. Is only used in surgical cases
Complete restoration made with the new Prettau® 3 Dispersive® zirconia on anodised titanium bars 100% digitally designed Made by DT Alexander Lichtmannegger, Zirkonzahn Education Center Brunico, Italy
Figure 1. The tooth set-up using tooth anatomies from the Heroes Collection virtual rooted tooth library integrated in the software.
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eeth are a mirror of a person’s life and individual lifestyle. Thanks to the new Prettau 3 Dispersive zirconia with Gradual-Triplex Technology - a triple gradient of natural colour, translucency and flexural strength - it is now possible to create accurate and individual restorations matching the patient’s functional and aesthetic requirements. For this case, my working protocol started with a digital acquisition of the oral situation with the Face Hunter 3D facial scanner and PlaneSystem®. The PlaneSystem is an innovative working method developed by MDT Udo Plaster in collaboration with Zirkonzahn that permits the registration and transfer of patient
data 1:1 into the digital world with no loss of information. In this way, it is possible to create accurate and individual restorations matching the patient’s functional and aesthetic requirements. For the tooth set-up, I used the Zirkonzahn.Modifier software, new add-on software specifically conceived for the fast creation of set-ups and prostheses, selecting the most appropriate tooth anatomies from the Heroes Collection virtual rooted tooth library integrated in it. After adapting tooth shapes to the patient’s physiognomy, I imported the planned restorations in the design software (Zirkonzahn.Modellier) as situ-scans, in order to design the titanium bars. Then, I milled, digitised the bars and adapted the planned maxillary and mandibular zirconia restorations on them.
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Question 1. The first known removable appliance using piano wire is attributed to:
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Question 6. Prettau Dispersive uses: a. Gradual Triptronic Technology b. Gradual Triplex Technology c. Gradual Tri Technology d. Gradual Trendy Technology Question 7. For the tooth setup, the software used was: a. Microsoft Word b. Director c. Modifier d. Tribeworks Question 8. Prettau Dispersive does not normally need any additional layering because: a. All people want white teeth b. The only shade is A3 c. Internal colour staining of the zirconia exists d. It does not take ceramic buildup well Question 9. In this case, additional stains were added called Zirkonahan: a. Apex b. Aquarell c. Acme d. Argent Question 10. The ceramic used later in the case was: a. Al Fresco b. Frisco c. Frometo d. Fresco
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