Dental Veneers

Biterite, as an approved Lava design Centre equipped with a Lava ST scanner, holds firm to the idea that the more you, the dental clinician, know about the materials and processes available to you from us the better we both can provide your patients with the very best aesthetic and practical outcomes.

CAD/CAM technology had made it possible to prepare restorations out of high strength ceramics like zirconia. This is due in part to the high flexural strength (almost two times higher compared to alumina) and high fracture toughness of the zirconia ceramic material.

Several companies are offering zirconia materials in dentistry and these materials are chemically similar, consisting of 3% yttrium oxide treated tetragonal zirconia polycrystals.

In many cases they are also treated with a very small concentration of alumina to prevent leaching of the yttrium oxide. This combination ensures the safety and longevity of zirconia restorations.

Even though zirconia from various manufacturers can be chemically similar does not mean that they are necessarily the same.

Loaves of bread are often chemically similar, but many factors outside of chemistry influence the final result; i.e., ingredients and baking process, the skill of the baker.

Although the zirconia ceramic is chemically similar, once processed, it can exhibit different mechanical and optical characteristics.

Working with zirconia, I really can experience the differences in machinability (e.g., wet milling and dry milling) and in sintering (e.g., temperature for Vita™ YZ-Cube > 1,530°C; temperature for 3M™ ESPE™ Lava™ Frameworks > 1,500°C; temperature for Cercon™ > 1,350°C).

As I pointed out at the start of this blog post, the more you know about Biterite’s work, including our products, equipment and services, the better we can serve your patients’ aesthetic and practical needs.

Please feel free to call or email us with your questions or concerns. You can also leave a comment here or find me on social media:

As always, I welcome your questions, comments and suggestions.

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I would like you to consider the following question: Are all zirconias the same?

Ceramic restorations in the posterior region were once limited to single units. CAD/CAM technology made it possible to prepare restorations out of high-strength ceramics.

With zirconia, clinicians can now place multi-unit restorations in both the anterior and posterior regions.

This is due in part to the high flexural strength and fracture toughness of zirconia.

Zirconia materials from different manufacturers, however, may be processed differently and have varying levels of stability.

Not all manufacturers, for example, have completed adequate in vitro and in vivo clinical studies.

Final restoration quality is directly dependent on careful and accurate control of the manufacturing process and thorough testing to substantiate material reliability.

You may now be asking, what can be different?

Here is a list of just a few things that may vary from manufacturer to manufacturer.

1. Processing parameters for pre-sintered zirconia affect performance attributes.

2. Differences in the zirconia powder affect the strength/long-term stability and translucency of the restoration.

3. The pressing condition and pressing method affect the marginal fit, strength and translucency of the restoration.

4. Pre-sintering conditions affect the strength of the pre-sintered material and its millability.

5. Colouring of the zirconia can affect the marginal fit, strength and translucency of the material.

You, the clinician, should be mindful of what zirconia product you are receiving for the final restorations.

Settling for a zirconia that is ‘just like the zirconia you asked for’ shouldn’t be good enough, and at Dental Laboratory London it isn’t!

We encourage you to ask such questions as: What brand of zirconia is being used? Why? Is there good science and good clinical data behind this product?

The Biterite staff and I firmly believe that once dental professionals understand the differences in zirconia materials, it becomes much easier for them to choose the best material for their patients’ needs.

If you’ve got any questions or concerns, feel free to leave a comment, email, or find me on social media:

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Coffee has been used to measure the weakest link in restorations - Adhesion

For more than seventy years researchers and clinicians have been seeking the solution to the weak-link in restorative dentistry: Adhesive bonding of the replacement material to a natural tooth.

This search has taken many interesting turns over the years and many a promising lead has often turned into a dead end road.

The story, however, is not just about adhesives.

The basic and obvious goal of restorative dentistry is that the repair or replacement should keep its size, shape and utility long after the work is completed.

In the 1942 edition of The Science of Dental Materials, Eugene Skinner wrote of silicate cement restorations: “Tooth structure can be imitated with complete satisfaction for the first few months after the restoration is placed, but almost invariably the material discolors and gradually disintegrates in the mouth.”

This was certainly not a situation to achieve a good outcome for the patient, nor did it well serve the reputation of the practitioner.

From the end of WWII to about the late 1950s, materials utilized for dental restorations were generally limited to gold foil, cast gold, amalgam, fused porcelain; in certain cases, silicate cement might be used instead.

During this same time period the primary resin filling materials used were methyl methacrylates and even these materials experienced high shrinkage during polymerization.

The long term results were not much better than they had been in earlier years.

By 1967 silicate cement restorative replacements had been developed. Even with its superior esthetic qualities and insolubility properties, acrylic resin did not resolve all of the earlier issues.

The sixth edition of The Science of Dental Materials, E. Skinner and R. W. Phillips discussed the problem of percolation, which the authors described as the alternative imbibing and extruding of liquids.

In other published works, the definition of percolation has been given as the expansion and contraction of the filling material due to thermal changes forming space between the filling and the tooth.

Some fifteen years earlier, Fluid exchange at the margins of dental restorations appeared in the Journal of the American Dental Association [1952;44(3)]. In this article the authors, R. J. Nelsen, R. B. Wolcott and G. C. Paffenbarger described their study of the volumetric changes of acrylic filling materials when subjected to thermal changes in the mouth.

The test subjects drank extremely hot coffee followed by very cold soft drinks, creating thermal cycling.
After accounting for known variables, the authors came to the conclusion that the space which developed between the restoration and the tooth surface allowed for a constant fluid exchange.
This, they said, explained the cause of secondary decay around the margins of existing restorations and, at the end of the article, noted the need for further investigation into dealing with the percolation problem.

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Patients are more likely than ever to request veneers in the practice

It was once good enough for teeth to merely be healthy and functional, but during the past twenty-five years patient expectations have changed considerably.

With the increasing popularity and availability of veneers, aesthetics now play an important part in the choice of dental restoration.

No longer are veneers restricted to the entertainment industry, as they were for the fifty years following their invention. Today they are sought after, and well within the financial reach of almost every patient who enters a dental clinic.

Veneers are now seen in the smiles of people from every walk of life. From teachers to lorry-drivers, business executives to postmen; all are now part of the ever-expanding number for whom dental aesthetics plays an important part in their daily lives.

The choice of ceramic or composite-resin veneers is basic to the patient evaluation protocol. Each has its own unique indications and contra-indications, advantages and disadvantages.

The first part of the decision process made by the dental practitioner must be to select the option that provides the best, the most satisfying outcome for their patient.

The second part of the decision process, equally as important as the first, is the selection of a reliable dental laboratory that utilizes state of the art materials, equipment and procedures.

Many of today’s dental practitioners know that by combining the quality of IPS e.max with the expertise of Biterite, they can have the very best outcome.

If you’ve got any comments or questions to add to the world of veneers, future or past, feel free to leave a comment here, or find us on social media:

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No matter how skilled the dentist or how well they are made, from time to time a tooth will veneer fractures or fall off.

There are several reasons why this happens, from the kind of veneer to the type and application of the adhesive.

There are, as we know, two main types of veneers; composite and porcelain. When created by a quality facility, such as like Biterite, veneers of these materials are of proven utility and longevity.

Yet, undeniably, failures do occur, but why?

There is no one thing that can make a veneer fail, but for the purpose of discussion we will take ‘fail’ to mean that the veneer falls off, chips, fractures or debonds.

A veneer may fracture, for example, if the bite comes together to weaken the material over time.

Other common causes of chipping or fracturing are the habitual chewing of ice cubes or the gnawing of steak or chop bones.

Failures due to accident, however, aren’t worth mentioning here.

When debonding occurs the obvious cause is that the adhesive has failed, but again, there is no single reason why this happens.

However, the most common and unfortunate cause is that the procedure, for a variety of reasons, was not done perfectly.

The solution for this type of failure is continuous training and practice combined with the exercise of great diligence during the application of the adhesive.

The failure of well-constructed and well-placed veneers is an uncommon occurrence. Should a patient come to you with a veneer failure, it is most important that they be assured how rare this is.

With a veneer fracture, of course, a new veneer will be required. In the instance of debonding, however, the veneer can often be rebonded or cemented back in place.

It is imperative that your patient be advised that should a veneer fail, from any apparent cause, that they contact you immediately.

This will not only reassure the patient, it will also go a long way toward precluding other problems such as dental decay or even bacterial infection.

If you’ve got any advice you’d like to share, or would like to contribute to the discussion, I welcome you to leave a comment here or contact me on social media:

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Lithium disilicate offers great strength without sacrificing aesthetic value

The IPS e.max system lithium disilicate ceramic (LS₂) clearly demonstrates you can achieve aesthetics and strength in a successful combination.

Particularly true in single-tooth restorations, this innovative ceramic, while two and a half to three times stronger than other glass-ceramics, consistently produces aesthetically pleasing results.

Lithium disilicate indication spectrum ranges from thin veneers (0.3 mm) and minimally invasive inlays and onlays to partial crowns, full crowns and three-unit anterior bridges. And, of course, implant superstructures can also be produced with this material.

Due to its high strength (360 – 400 MPa), restorations fabricated with this lithium disilicate can be cemented with the different methods we have spoken of previously.

With their natural-looking colour and optimal light transmission, lithium disilicate restorations offer highly aesthetic solutions that never fail to achieve a highly satisfactory outcome.

Depending on the needs of your patient, restorations can be veneered with a highly aesthetic material or they can be fabricated to full contour and then economically characterized.

Even if the tooth’s core is dark in colour (e.g., discoloured stump or titanium abutments), you no longer have to resort to zirconium oxide or metal-ceramic solutions.

You can tell your lab about the colour that needs to be masked and we will choose the appropriate IPS e.max lithium disilicate material that will meet the required opacity to restore the natural aesthetic appearance of the tooth.

As always, I welcome your comments on any subject we discuss here. Feel free to welcome to leave a comment here or find me on social media:

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Oral health is what we do. While I work personally in the lab, the restorations we at Biterite contribute to are an important piece of the oral health jigsaw puzzle.

For this reason, I’m going to be discussing oral health, including how we define it, it’s place in our general health, and we maintain it over the course of this week.

Today, I’m talking about defining oral health.

In the United States, the Surgeon General has defined oral health as: “Being free of chronic oral-facial pain conditions, oral and pharyngeal (throat) cancers, oral soft tissue lesions, birth defects such as cleft lip and palate, and other diseases and disorders affecting oral, dental, and craniofacial tissues.”

These tissues, whose functions we often take for granted, represent the very essence of our humanity.

They allow us to speak and smile; sigh and kiss; smell, taste, touch, chew, swallow, cry and convey emotions through facial expressions. They also provide protection against infection.

The craniofacial tissues also provide a useful means to understanding organs and systems in less accessible parts of the body. A thorough oral examination can detect signs of nutritional deficiencies as well as a number of systemic diseases, including microbial infections, immune disorders, injuries, and cancer.

The phrase the ‘mouth is a mirror’ has been used to illustrate the wealth of information which can be derived from examining oral tissue.

On-going research has found connections between chronic oral infections and heart and lung diseases, stroke, low-birth-weight and premature births. Periodontal disease is also associated with diabetes.

As long ago as 1948 the World Health Organization expanded the definition of health to mean “a complete state of physical, mental, and social well-being, and not just the absence of infirmity.”

It follows that oral health must also include well-being; just as we now understand that nature and nurture are inextricably linked, and mind and body are both expressions of our human biology, so, too, we must recognize that oral health and general health are inseparable.

Ignoring signs and symptoms in the mouth will always be to our detriment.

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If you want to get the most of out your lab work, it all starts with an accurate, reliable impression, but even the most experienced practitioner can encounter difficulties when taking one.

I’ve got special permission from 3M ESPE to share with you a number of tips developed by that company.

1. Tearing/rough surfaces: Rough occlusal and/or incisal surfaces, tearing on the margin of the preparation, and poor lamination between the tray material and wash can be due to a number of causes. To avoid these issues, pay close attention to your retraction technique. Additionally, pay close attention to the recommendations for the material’s oral working time, and set a timer to ensure the tray is left in the mouth for the full set time.

2. Tight crowns: This problem can be caused by early removal of the impression tray from the mouth, a poor bond of the material to the tray, or seating an impression tray with material that is partially set. Again, closely follow the recommended working and setting times, and always use a VPS tray adhesive according to instructions.

3. Short crowns: Trays with weak or low walls can provide insufficient support during impressioning, leading to short crowns. To address this issue, use custom or inflexible trays — preferably metal. Short crowns can also be due to teeth coming into contact with the tray. Before seating confirm that teeth do not touch the tray.

4. Voids: Voids are one of the most common impressioning issues. Voids can compromise the restoration’s fit and function. This issue may indicate a needed improvement to your syringe technique. Use a stirring motion while syringing, making sure to keep the syringe tip immersed to avoid trapping air.

5. Tray seating: This step presents the possibility for a number of errors.

•  Ledges — Position the tray before seating, and use a slow, steady, vertical seating motion.

•  Drags — This can occur when the tray is placed and seated in one motion or when teeth rebound off the tray and slide into position. Seat the tray slowly after carefully positioning it in the mouth, avoiding contact of teeth with the tray.

•  Rocking crowns, slanted or wavy teeth — Eliminate tray movement after seating using passive pressure on the tray to immobilize it for the full recommended oral set time.

6. Bite registration: When excessive occlusal adjustment is necessary for restorations, poor interocclusal records are likely a factor. To combat this, use a dimensionally stable bite registration material, and ensure it is trimmed properly. Additionally, monitor patients to confirm they do not move during the procedure.

7. Surface inhibition: If the surface of the impression material is not set, tacky to the touch, and visually resembles the surface of an orange peel, a number of factors may be the culprit; exposure to air-inhibited methacrylates or residues from custom temporary materials, for example. Avoid this problem by waiting to fabricate the temporary crown until the final impression has been made, then remove the air-inhibited layer on any composites, adhesives, or core build-ups in the impressioning area.

I suggest that a reliable impression material, such as 3M™ ESPE^™ Impregum^™ Soft Polyether Impression Material, and the right technique, impression-taking can be predictable and highly accurate.

I hope you found this guide helpful. If you’d like to discuss this article or other dental subjects, feel free to leave a comment here or get in touch on our social media accounts:

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Patient fear can come from the mystery and misunderstandings of dentistry

When you’ve been wading through root canals, extractions, restorations and even implants, your perceptions change; what’s totally commonplace to a dentist can be mysterious and even frightening to a patient.

Take, for example, a dental veneer procedure — you’ve done this dozens, if not hundreds of times, but it’s likely the patient you’re performing each procedure on is totally new to it.

We all know a properly informed and prepared patient will be less anxious, making it easier for you to perform the particular procedure.

Not to mention a well-informed patient will have a more realistic expectation of the outcome. So let’s look at a dental veneer procedure and how you might prepare the patient to avoid both of these problems.

Tell your patient the first step will be examination, to make sure that dental veneers are appropriate. You could also say x-rays may be taken.

Gently explain the scariest parts of the procedure – taking x-rays, enduring a local anaesthetic, removing half a millimetre of enamel – in plain language.

Explain that the model or impression of the tooth/teeth you make will be sent to Biterite (or your current lab), and the lab will construct a tooth.

If the patient will have an unsightly dental appearance in the meantime, they could also be assured a temporary is available.

Tell your patient that you will temporarily place the veneer to examine its fit and colour and may repeatedly remove and trim it to achieve the proper fit.

Explain the cleaning, polishing and etching that allows for a strong bonding process and that they will be a follow-up visit to check how the gums are responding to the veneer and to re-examine the veneer’s placement.

All this might seem obvious, but it’s incredible how the clinical world of dentistry can remove us from the fears of the average patient. Keeping in mind the fear and the mystery so often attached to our industry will help us understand the patient’s needs while in the practice.

If you have any comments or questions, feel free to leave a comment here or get in touch on our social media accounts:

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In the past I’ve used this blog to talk about the huge importance of dentist-patient communication.

As important as the patient-practitioner relationship is, the dentist-dental lab relationship is often overlooked.

Today I’m going to take a look at how modern technology can enhance communication between the dentist and the dental lab.

Until very recent advances in computers, digital cameras, and mobile phones, communication was more or less limited to in-person or landline telephone conversations.

Letters and other documents, as well as printed photographs, travelled by post or via fax machines. Now, nearly all communication, verbal and written, has gone digital.

Even in the very recent past, the largest amount of information flowing between a dentist and lab has been by way of the impression.

Now, digital impression systems provide the opportunity for better, more accurate, communication.

The resultant virtual model becomes a powerful communication tool, especially since it allows for the magnification of the image allowing scrutiny of detail not possible a traditional impression.

Complete and accurate information sent from the dentist to the lab can eliminate many questions or uncertainties.

After the scan and prescription are complete, the case is sent electronically to the lab. The dentist almost immediately has confirmation that the case ‘file’ has been received.

For labs with CAD software, like us, cases can easily be scanned and imported into the system.

We can now review cases electronically, and any issues or questions that used to take days being sent back and forth can quickly be resolved via a screen shot, email, or phone call.

If a challenge arises that requires lab-dentist consultation, it can be done online with everyone participating in the discussion.

Dental Laboratory London is committed to providing state of the art products and communications through highly-trained personnel and the latest innovations that technology has to offer.

As always, we welcome any comments or discussion about new modes of communication for labs and dentists. Feel free to leave a comment on this blog, or get in touch on our social media presence:

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