IPS e-max for all ceramic restoration

e.max press

Lithium disilicate (LS2) glass-ceramic is ideally suitable for the fabrication of monolithic single-tooth restorations. This innovative ceramic provides highly esthetic results and, compared to other glass-ceramics, demonstrates a strength that is 2.5 to 3 times higher. Supported with zirconium oxide, it may also be used for bridges in the posterior area.

The material is used in the dental laboratory in conjunction with either the press or the CAD/CAM technology. Given the high strength of 360-400 MPa, the restorations offer flexible cementation options. Depending on the patient situation, the restorations may be veneered in a highly esthetic manner or, if fabricated as monolithic restorations, stained.

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E-max crowns

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E-max crowns

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E-max Veneers

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E-max Veneers

Even if the preparations demonstrate a dark shade (e.g. as a result of discolouration or titanium abutments), all-ceramic restorations may be fabricated. Inform your laboratory about the die shade and the dental technicians then selects the IPS e.max lithium disilicate material in the required opacity in order to redesign the true-to-nature esthetic appearance.

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E-max press

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Blocks of E-max press

Indications

  • Thin veneers (0.3 mm)
  • Minimally invasive inlays and onlays
  • Partial crowns and crowns
  • Implant superstructures
  • 3-unit anterior/premolar bridges (only IPS e.max Press)
  • 3-unit bridges (zirconium-oxide supported only IPS e.max CAD)

The highlights

  • True-to-nature shade behaviour for highly esthetic solutions
  • Durable restorations due to the high strength
  • Minimally invasive preparation for treatment that is gentle to the tooth structure
  • Versatile use and comprehensive range of indications
  • Lifelike esthetics, irrespective of the shade of the preparation
  • Adhesive, self-adhesive or conventional cementation depending on the indication

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Zirconia – All ceramic restoration

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Zirconia Bridge

What is zirconia?

It is zirconium dioxide ( ZrO2), a white solid used in ceramic glazes and refractory coatings, and as a synthetic substitute for diamonds in jewellery.

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Zirconium dioxide

Zirconium

Periodic_tablePeriodic Table

This is a metallic element with the atomic number of 40 and the symbol Zr. Despite the fact that zirconium can only be found in a combined form in nature, it is very abundant on Earth, being a highly reactive element. This element belongs to the transition metals, a group of neighboring metals on the periodic table of elements which includes palladium, silver, cobalt, copper, zinc, and nickel, among many others

Despite the fact that zirconium can only be found in a combined form in nature, it is very abundant on Earth, being a highly reactive element. This element belongs to the transition metals, a group of neighboring metals on the periodic table of elements which includes palladium, silver, cobalt, copper, zinc, and nickel, among many others.

Before going into details, we decided to do an overview of zirconium. This is a metallic element with the atomic number of 40 and the symbol Zr. Despite the fact that zirconium can only be found in a combined form in nature, it is very abundant on Earth, being a highly reactive element. This element belongs to the transition metals, a group of neighboring metals on the periodic table of elements which includes palladium, silver, cobalt, copper, zinc, and nickel, among many others. – See more at: http://www.dental-zirconium.com/#sthash.wb622dwA.dpuf

Structure

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Zirconium(IV) oxide

Three phases are known: monoclinic <1,170 °C, tetragonal 1,170–2,370 °C, and cubic >2,370 °C. The trend is for higher symmetry at higher temperatures, as is usually the case. A few percentage of the oxides of calcium or yttrium stabilize the cubic phase. The very rare mineral tazheranite (Zr,Ti,Ca)O2 is cubic. Unlike TiO2, which features six-coordinate Ti in all phases, monoclinic zirconia consists of seven-coordinate zirconium centres. This difference is attributed to the larger size of Zr atom relative to the Ti atom. [Taken from Wikipidia]

Chemical reactions

Zirconia is chemically unreactive. It is slowly attacked by concentrated hydrofluoric acid and sulfuric acid. When heated with carbon, it converts to zirconium carbide. When heated with carbon in the presence of chlorine, it converts to zirconium tetrachloride. This conversion is the basis for the purification of zirconium metal and is analogous to the Kroll process. [Taken from Wikipidia]

 

Zirconia in dentistry

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Zirconia is a very hard ceramic that is used as a strong base material in some full ceramic restorations. The zirconia used in dentistry is zirconium oxide which has been stabilized with the addition of yttrium oxide. The full name of zirconia used in dentistry is yttria-stabilized zirconia or YSZ.

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Cross-section of a zirconia crown

The zirconia substructure (core) is usually designed on a digital representation of the patients mouth, which is captured with a 3d digital scan of the patient, impression, or model. The core is then milled from a block of zirconia in a soft pre-sintered state. Once milled, the zirconia is sintered in a furnace where it shrinks by 20% and reaches its full strength of approximately 850MPa.

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Milling of zirconia block

The zirconia core structure can be layered with aesthetic feldspathic porcelain to create the final color and shape of the tooth. Because bond strength of layered porcelain fused to zirconia is not strong, “monolithic” zirconia crowns are often made entirely of the zirconia ceramic with no aesthetic porcelain layered on top. Zirconia is the hardest known ceramic in industry and the strongest material used in dentistry. Monolithic zirconia crowns tend to be dense in appearance with a high value and they lack translucency and fluorescence. For aesthetic reasons, many dentists will not use monolithic crowns on anterior (front) teeth.

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Translucency of a zirconia crown

By using crowns made of metal zirconia, then merge the porcelain on the outside, zirconia crowns allow light to pass as a normal tooth would and that gives a natural look, unlike other metal cores that block the light. The normal too hot/cold sensations that can be felt with other crowns does not normally occur because of reduced thermal conductivity, this being another strong point for zirconia.

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Quality Assurance

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A case of aesthetic makeover (I) with full porcelain bridge – Replacing missing teeth

Aesthetic-Dentistry

A lady came to our clinic complained that she wanted an immediate replacement of her front teeth that were just extracted a week ago due to gum problem. She said that she didn’t dare to go out of her house due to her disfigured appearance. She was sad and embarrassed

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There reason why she lost her front teeth was due to deep-bite (her lower teeth were biting at the back of her upper front teeth) which result in stripping of the gum on the palate (traumatic occlusion). Eventually, this lead to periodontitis (gum disease) and loosening of her teeth. Sadly, she had to have her upper teeth removed.

After examination and assessment of her teeth, we came out with a few treatment plans:

  1. Correction of the occlusion (biting) by means of orthodontic treatment followed by orthognathic surgery to correct her jaw misalignment — which will takes her 2-4 years
  2. Dental implant to replace the missing front teeth — Required bone block to build back resorbed  alveolar ridge and the implant might not be lasting due to the occlusion problem
  3. A dental bridge from her canine to the other canine (a 6 unit bridge)

After discussed with her, she decided to go for the third option – a dental bridge. She preferred the zicornia type of material for aesthetic reason.

For a mean time to allow gum healing, we prepare a ‘vacuum formed’ denture which she used to cover the missing teeth.

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A temporary denture

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She wear the denture while waiting for the gum to heal

Final outcome, a 6 unit zicornia bridge was cemented onto her teeth…

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Final result

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6 unit zicornia bridge

Possible problems/risks for a dental bridge:

  1. Fracture bridge
  2. Possibility of devitalizing the teeth during preparation of teeth ending up needed root canal treatment.

 

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