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Does the seating of a NuSmile ZR crown proceed in the same way as the seating of an SSC crown?
How is steel crowns sterilized?
The sterilization of stainless steel crowns, used for restoring primary and permanent teeth, can be done using several effective methods
that ensure the proper level of hygiene and safety in a dental practice. One common method is chemical sterilization, which involves
disinfecting the crowns with specialized chemical agents that have a broad antimicrobial effect. These preparations eliminate
microorganisms from the surface of the crowns, but their effectiveness depends on strictly following the manufacturer's instructions,
including exposure time and storage conditions. Another popular solution is autoclave sterilization, a device that uses high temperature
and pressure to thoroughly clean dental tools and materials. Crowns are placed in special bags or containers and then subjected to
steam under pressure, effectively removing bacteria and viruses. Alternatively, steam sterilization, which uses saturated steam as a
disinfectant, is also a viable option. Thanks to high temperature and humidity, steam acts as an efficient biocidal agent, destroying
pathogens on the crown's surface. All of these methods—chemical, autoclave, and steam sterilization—are considered safe and
effective for preparing stainless steel crowns for reuse in pediatric dentistry.
Can a stainless steel crown be a contraindication for magnetic resonance imaging (MRI)?
Are prefabricated stainless steel crowns (SSC/PFMC) a contraindication to MRI?
No. The presence of a prefabricated stainless steel crown is not an absolute contraindication for an MRI scan. The decision to perform the examination rests with the radiologist and the referring physician and should take into account the location of the imaged area.
Do stainless steel crowns cause artifacts in MRI images?
Yes. Like other metal elements, stainless steel crowns can generate artifacts and local signal distortions. The scale of the artifact depends, among other things, on the alloy composition, the magnetic properties of the material, and the degree of mechanical deformation of the crown during clinical adaptation.
What is the typical range of an artifact from a stainless steel crown?
Based on experimental data, artifacts are usually locally confined - most often within a few centimeters from the restoration (values up to approx. 10cm). Clinical significance depends on the location of the examined structure.
Does the material composition of the crown matter for the size of the artifact?
Yes. The magnetic properties of stainless steel depend on its composition and crystalline structure. Higher nickel content and an austenitic structure are associated with lower magnetic permeability and potentially smaller artifacts. Mechanical deformation can change the magnetic properties of the alloy.
Are there in vivo clinical studies evaluating the impact of SSCs on MRI quality in children?
A systematic literature review (European Archives of Paediatric Dentistry, 2021) did not identify in vivo clinical studies meeting the quality criteria that would allow for a clear determination of the impact of SSCs on the diagnostic quality of MRI in children. Available data mainly come from in vitro studies.
Is routine removal of stainless steel crowns recommended before MRI?
No. Routine removal of SSCs before an MRI scan is not recommended. The decision may be considered individually if the expected artifact could significantly limit the diagnostic value of the examination in a given anatomical location.
What procedure is recommended before referring a patient with SSCs for MRI?
It is recommended to: inform the radiologist about the presence of SSCs, assess the stability of the crown, provide information about the location of the restoration, and individually assess the clinical significance of the artifact relative to the purpose of the examination.
Do SSCs generate larger artifacts than orthodontic appliances?
Usually not. Fixed orthodontic appliances involve a larger volume of metal and more often cause more extensive artifacts than a single stainless steel crown.
What if the patient has several stainless steel crowns (SSC/PFMC)?
The presence of multiple stainless steel crowns does not automatically contraindicate an MRI scan, but it may increase the extent and severity of image artifacts.
Available experimental data indicate that: their range depends on the properties of the alloy, the size of the element, and its position; a larger total volume of metal in the oral cavity can cause a larger area of signal distortions.
Clinical significance primarily depends on: the location of the examined area (head and neck MRI vs. distant body areas), the number and distribution of crowns, the diagnostic goal of the examination, and the required image quality in a given area.
In the case of examinations involving head and facial structures, there is a greater risk of artifacts than in anatomically distant examinations.
Current literature does not provide in vivo clinical studies in children that would allow determining a threshold for the number of SSC crowns that significantly limit the diagnostic value of MRI. For this reason, an individual case assessment and prior consultation with a radiologist are recommended.
Can steel crowns be shortened/trimmed?
Yes, steel crowns for primary and permanent teeth can be shortened, trimmed, and bent to better fit clinical conditions. If there is a need
to shorten the crown, specialized scissors for cutting steel crowns are used. These allow for precise adjustment of the crown’s length to
the anatomical conditions of the tooth, especially in more challenging cases. If shortening the crown affects its contour or clasp,
modeling pliers can be used. These tools allow for proper bending and shaping of the crown, restoring its functionality and retention
stability. Shortening steel crowns is a permissible and often necessary practice in everyday endodontic work. However, it is crucial that
all modifications be made in accordance with the manufacturer's instructions and using the appropriate dental tools, ensuring the
effectiveness and safety of the steel crown.
How durable are steel crowns for primary and permanent teeth?
The durability of stainless steel crowns used in pediatric dentistry depends on many factors – including the quality of the crown, the conditions in the patient’s oral cavity, their habits (e.g., bruxism), as well as hygiene and regular dental check-ups. In general, stainless steel crowns for primary teeth are considered highly durable, but their lifespan may vary depending on the case.
Under favorable conditions, a stainless steel crown can last several to over a dozen years if properly placed and not exposed to excessive forces such as teeth grinding. However, it’s important to remember that risk factors – such as bruxism, poor oral hygiene, or a sugar-rich diet – can significantly shorten the crown’s lifespan.
To maintain the durability of stainless steel crowns, it is essential to regularly visit a pediatric dentist who can assess their condition and plan adjustments or replacement if necessary. The durability of each crown is individual, so it is impossible to specify exactly how long it will last – what matters most is regular monitoring and proper hygiene.
What cement should be used to cement steel crowns?
In pediatric dentistry, stainless steel crowns are most commonly cemented using glass ionomer or resin-based cements, with the
choice depending on the clinical situation and the dentist’s preferred technique. Glass ionomer cements, such as GC Fuji PLUS, are
widely recommended due to their strong adhesion to both tooth structure and metal surfaces, ensuring stable placement on both
primary and permanent teeth. Selecting the right cement ensures the crown's durability and the overall success of the treatment,
making compatibility with the crown type and workflow essential.
In the cases I treat, space loss due to caries is a common occurrence. Can I use zirconia crowns in such situations?
Yes, but always choose a crown size that fits within the available space and prepare the tooth accordingly. Typically, this will be one or two sizes smaller than with traditional SSC crowns, and even smaller if there is greater space loss.
Each time, this requires tooth preparation to fit the crown. For lower posterior crowns, it may turn out that a contralateral upper crown will work best.
We also offer NuSmile ZR Narrow 1st Primary Molars crowns, specifically designed for these types of posterior cases. NuSmile ZR Central and Lateral crowns are available in size 0 for such situations.
Can you send me materials that will help me better understand the technique of working with zirconia crowns?
Yes, we offer training materials in the form of technical videos available on the Nu Smile YouTube channel, which present preparation and placement procedures (on real patients), allowing you to achieve the highest level of effectiveness and efficiency when working with both anterior and posterior NuSmile ZR crowns.
Clinical videos are available at:
https://www.nusmile.com/zirconia-tutorials
Dental for Children also organizes practical training sessions. We encourage you to familiarize yourself with the list of upcoming training sessions.
How to remove a cemented zirconia crown?
To remove a cemented zirconia crown, it is recommended to use a high-speed handpiece with a diamond bur and copious water cooling. Begin by making a vertical cut along the center of the buccal/labial or lingual surface of the crown, starting from the gingival margin. Throughout the procedure, consistently use water spray to prevent overheating. Then, extend the cut through the occlusal or incisal surface of the crown.
Once the cut is made, a surgical spoon excavator can be inserted into it and gently rotated. This should cause the gap to widen and the crown to break into pieces. It is important to place a 2x2 gauze or similar material to catch small crown fragments as it fractures, preventing them from falling into the patient's mouth.
Cement remnants on the tooth can be removed using hand instruments or a high-speed handpiece. For a vital tooth that has not undergone prior endodontic treatment, local anesthesia may be necessary.
I'm having difficulty seating adjacent and opposing posterior zirconia crowns. What should I do?
First, ensure that sufficient tooth structure has been removed to allow passive seating of the crowns. Preparation in this case will be more aggressive than for a "snap-fit" stainless steel crown (SSC).
When placing adjacent crowns or in cases of mesiodistal space loss, we recommend using NuSmile ZR Narrow 1st Primary Molar crowns. These crowns are 0.5 mm narrower than standard NuSmile ZR 1st Primary Molar crowns.
You can also try using a contralateral upper posterior crown for restoration in the lower arch in cases of mesiodistal space loss. Some clinicians slightly reduce the distal surface of the primary canine if necessary.
What are NuSmile ZR crowns made of?
NuSmile ZR crowns are made of high-quality Japanese monolithic Y-TZP zirconia ceramic.
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Is pulp therapy necessary when using steel crowns?
Pulp therapy is not always required when placing stainless steel crowns; it depends on the clinical condition of the tooth. In cases of
deep caries or inflammation, it may be necessary, but it is not performed routinely. The final decision is made by the dentist based on
pulp vitality and root condition. Stainless steel crowns are primarily used to restore severely damaged primary teeth, and pulp treatment
is done only if medically indicated.
What are SSC NuSmile and SHINSHUNG steel crowns made of?
SSC NuSmile and SHINSHUNG crowns are made from 316L stainless steel, an austenitic alloy known for its durability and corrosion
resistance. The "316" indicates approximately 16% chromium content, and the "L" denotes a low-carbon variant, which minimizes
corrosion risk and enhances material strength. 316L stainless steel is highly resistant to moisture, acids, and chemicals, making it well-
suited for the oral environment. It is biocompatible, meaning it is safe for contact with biological tissues and does not trigger allergic
reactions or interact negatively with the body. It also offers high compressive strength and resistance to chewing forces, making it ideal
for crowns on primary teeth. These qualities ensure durability, safety, and comfort for pediatric dental applications.
How to properly cement a zirconium crown?
Cementing zirconia crowns, such as NuSmile ZR, requires following several key principles that affect the durability and effectiveness of
the procedure. The most important factor is preventing contamination of the crown's inner surface with saliva or blood, as even a small
amount can significantly reduce the cement's adhesion.
Step 1: Fitting the crown – using Try-In crowns
To avoid saliva contact, NuSmile has developed special Try-In crowns, identical in size and shape, for multiple fittings. Try-In crowns
can be sterilized and reused, ensuring a safe solution during trials.
Step 2: Cleaning the surface in case of contamination
If the inner surface of the NuSmile ZR crown gets contaminated, it should be cleaned by one of the following methods:
● using aluminum oxide (Al₂O₃),
● or using Ivoclean, a cleaner designed for cleaning prosthetic work.
Step 3: Choosing the cement
For cementing zirconia crowns, glass ionomer cements and resin cements are commonly used, depending on the clinical situation and
the dentist's preference. One recommended material is GC Fuji PLUS – a hybrid cement combining the properties of glass ionomers and
composite resins, providing strong adhesion.
Step 4: Pulp therapy
If pulp therapy was performed and a material containing eugenol was used, it should be covered with glass ionomer before cementing
unless the cement used also utilizes glass ionomer technology.
Step 5: Seating the crown
The NuSmile ZR crown should fit passively. Once seated, it should be gently held in place until the cement self-hardens.
Will zirconia crowns fit the same way as steel crowns?
Zirconia crowns, such as NuSmile ZR, are seated similarly to steel crowns, but they require slightly different tooth preparation.
Compared to steel crowns, preparation for zirconia crowns is more extensive around the entire circumference of the tooth, requiring
about 20% more reduction of hard tissues. The exception is occlusal reduction, which is comparable to that performed with steel
crowns.
For NuSmile ZR crowns, it's essential to avoid the "snap fit" effect (the characteristic click when seating), as this may cause microcracks
or stresses in the zirconia material. The zirconia crown should have a passive fit, and its position should be maintained until the cement
self-hardens.
The key to proper seating of a zirconia crown is always ensuring that the tooth preparation matches the shape of the crown, not the other
way around.
Is pulp therapy necessary when using zirconia crowns?
Similar to steel crowns, pulp therapy is generally not necessary when placing NuSmile ZR zirconia crowns. It may only be indicated if
there is advanced decay or other pathological changes in the tooth pulp.
The decision regarding possible endodontic treatment should always be made by the dentist based on the clinical assessment.
Can zirconium crowns be crimped?
No, zirconia crowns are not designed for crimping.
How do gums react to zirconia crowns?
Gum response is very good due to the anatomically correct contours and high biocompatibility of zirconia crowns.
With a properly fitted crown, an improvement in gum health is expected within 7-10 days. With proper oral hygiene, gum health should be maintained long-term.
What kind of longevity can I expect from zirconia crowns for anterior teeth, posterior teeth, and canines?
Zirconia crowns do not chip or discolor and should last until the physiological exchange of the tooth.
Zirconia crowns have over 13 years of documented success in adult dentistry and over 8 years of success in pediatric dentistry.
When properly applied, according to instructions, an efficacy of 99% or higher can be expected.
Can I repair a chipped zirconia crown?
Due to the structural properties of zirconia, zirconia crowns cannot be repaired.
If a zirconia crown fractures (which is very rare), it must be replaced. Dental for Children will replace an occasionally fractured crown at no additional cost, provided that the damaged crown is returned after replacement.
Please contact us before returning the crown for replacement.
What are the advantages of using Try-In crowns?
Scientific studies, particularly the work of Kern et al. published in Dental Materials 24, 508 (2008), have shown that saliva contamination negatively affects the bond strength of cement to zirconia.
Using Try-In crowns ensures optimal cement retention because it prevents contamination of the definitive ZR crown with saliva or blood before its final cementation.
If endodontic treatment is required after a zirconia crown has been cemented, how should the access opening in the crown be repaired?
A hole in a crown can be repaired in a similar way to the open-face technique—by creating small mechanical undercuts beneath the opening and lightly roughening the zirconia surface within the access area.
Then, the defect should be restored with composite material.
What is NeoPUTTY®?
NeoPUTTY is a pre-mixed bioactive bioceramic material for pulp and root canal treatment. It consists of a very fine, inorganic tricalcium/dicalcium silicate powder suspended in an anhydrous organic liquid.
The product is ready to use—no mixing required. NeoPUTTY sets in vivo in the presence of moisture from surrounding tissues.
How does NeoPUTTY differ from resin-based materials containing MTA?
Unlike inert resin-based materials that only contain MTA, NeoPUTTY:
- Is bioactive – releases calcium and hydroxyl ions from the surface, promoting hydroxyapatite formation and providing a bioactive seal.
- Contains pure tricalcium/dicalcium silicate and a radiopacifier.
- Is dimensionally stable – unlike resin materials that can shrink.
- Is biocompatible and non-cytotoxic.
- Has broader clinical indications.
- Is more radiopaque.
- Does not contain resin, which allows for maximum MTA concentration and maximum bioactivity.
Resin materials containing only a portion of MTA cement did not consistently demonstrate biocompatibility in cell culture studies; observed toxicity may be related to incomplete resin polymerization.
How does NeoPUTTY differ from resin-based MTA-containing materials?
Unlike inert resin-based materials containing only MTA additives, NeoPUTTY:
- Is bioactive – releases calcium and hydroxide ions from the surface, supporting hydroxyapatite formation and providing a bioactive seal.
- Contains pure tricalcium/dicalcium silicate and an opacifying agent (radiopacifier).
- Is dimensionally stable – unlike resin materials, which may shrink.
- Is biocompatible and non-cytotoxic.
- Has broader clinical indications.
- Is more radiopaque.
- Contains no resin, which allows for maximum MTA concentration and maximum bioactivity.
Resin materials containing only a portion of MTA cement did not consistently demonstrate biocompatibility in cell culture studies; observed toxicity may be related to incomplete resin polymerization.
What is the shelf life of NeoPUTTY?
The product has a 3-year shelf life.
To prevent the material from hardening, the syringe should be capped immediately after each use.
The syringe should be stored in the provided protective aluminum container.
Is an applicator tip needed for dispensing NeoPUTTY?
No, an application tip is not required.
Remove the cap from the syringe and dispense the appropriate amount of NeoPUTTY onto a mixing pad. Then, using the chosen instrument, transfer the material to the treatment site.
After each use, immediately recap the syringe and place it back into its protective aluminum container.
How much NeoPUTTY should be applied to ensure its effectiveness?
For pulpotomy, as a liner, base, or pulp capping — apply a layer at least 1.5 mm thick.
For apexification, gently condense NeoMTA in the apical area to form a barrier 3-5 mm thick.
What is the best tool for NeoPUTTY application in surgical procedures such as apical filling, apexification, or perforation repair?
You can use any convenient tool to place a small cone or cylinder of NeoPUTTY into the treatment site.
Suitable tools include:
- Messing gun,
- spoon/amalgam carrier,
- Dovgan MTA applicator,
- MAP™ system.
Inverted paper points or gutta-percha points can help guide the material into the canal to the apex during apexification.
What is the best instrument to use to introduce NeoPUTTY into the pulp chamber during a pulpotomy?
NeoPUTTY is recommended to be applied using:
- a plastic instrument,
- a Hollenbach instrument,
- a spoon excavator/amalgam carrier,
- an MTA applicator.
The material can be gently spread with a moist cotton pellet, an amalgam plugger, or a ball burnisher.
Can I apply NeoPUTTY and finish the restoration before the material fully sets?
Yes. The material is immediately resistant to washout, so the restoration can be performed directly after applying NeoPUTTY.
NeoPUTTY will set and harden under the restoration. The material is dimensionally stable—it shows no shrinkage and minimal expansion.
Should I secure NeoPUTTY before performing a rebuild?
While not strictly necessary, a quick and convenient solution is to apply a layer of flowable composite, light-cured glass ionomer, RMGI, IRM®, ZOE, or other liner material over NeoPUTTY before performing the final restoration.
If you are using a flowable composite that requires etching, etch the tooth — not NeoPUTTY — and then proceed with the restoration.
What is the setting time of NeoPUTTY?
NeoPUTTY sets in vivo in approximately 4 hours.
The setting process begins in the presence of moisture from periapical tissues, dentinal tubules, or pulp.
Note: To prevent premature hardening of the material, recap the syringe immediately after each use.
Should the kit or its components be stored in the refrigerator?
NeoPUTTY should be stored at room temperature, with the syringe tightly closed, in the supplied protective aluminum container.
Refrigeration does not extend shelf life and causes the material to become excessively viscous, making it difficult to use immediately.
What is the difference between NeoMTA® 2 and NeoPUTTY™?
NeoPUTTY does not require mixing—it is a homogeneous, cohesive, non-sticky mass (putty) from start to finish and does not dry out between applications.
- NeoPUTTY has approximately 25% greater radiopacity than NeoMTA 2 (8.1 vs 6.5 mm aluminum equivalent).
- NeoPUTTY syringes minimize material waste—they allow for precise dispensing right to the very end thanks to a positive-feed plunger.
- NeoMTA 2 is a powder and gel material for manual mixing, intended for 10 applications in vital pulp therapy and endodontics, including obturation and sealing (according to NeoMTA 2 IFU).
What are the similarities between NeoMTA 2 and NeoPUTTY?
Both products are bioactive, bioceramic MTA-type cements.
They release calcium and hydroxyl ions, promoting hydroxyapatite formation on the surface, which aids in sealing and healing.
They are resin-free, ensuring maximum bioactivity.
After application, they exhibit a high, alkaline pH; literature indicates their in vitro antimicrobial activity.
They are color-stable and do not cause discoloration; they contain tantalum oxide (tantalite) as a radiopacifier. They do not contain bismuth oxide, which can cause tooth discoloration.
They are immediately resistant to wash-out after application.
After setting, they exhibit low water solubility (<3%).
They are dimensionally stable, with minimal expansion during setting.
They contain very fine, hydraulic tri-/dicalcium silicate powders.
Are there rings in the kit that fit permanent molars?
Larger band sizes should fit most first permanent molars. If not, the appliance will need to be fabricated in the laboratory.
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