Can YOU spot the crown?

Here is an interesting case you will like. So first up a question... which tooth is a crown? 

We've shown this case many times during presentations and lectures and most people can correctly identify the Upper Right Central as a crown - it has that slightly brighter and more opaque look to it and lacks an element of vitality.

This aesthetic effect is common with porcelain fused to metal crowns and is caused by the inability for the restoration to allow light to pass through, as it does with a natural tooth.

Even if the shade of the restoration is perfect and the shape, contour and morphology are great this 'bright' effect is often difficult... no, let's say often impossible, to overcome.

OK, so here is the truth about this case.... both centrals are crowns, except one has a root treated tooth with gold post and core.

When we started this case we didn't know that the Upper Right Central had this underlying core, so we didn't take this in to account when making the 2 metal free crowns.

So, the 2 crowns are made together, the same shade and same morphology, yet one looks bright... all caused by the root treated tooth underneath.

What lessons should be learnt?

1. Dentists - Always tell the laboratory the condition of the underlying tooth with metal free crowns
2. Technicians - If the dentists doesn't tell you what the underlying tooth condition is, ask!
3. Dentists - Translucent Metal free is not the be all and end all. So be case selective about the material used.
4. Technicians - have a variety of restorations available with a variety of opacity levels, this way you can inform the dentist as to the best restoration for each individual case
5. Dentists - Send photos of preps, this gives the technician the best chance of choosing the best restoration
6. Dentists - prescribe a crown if necessary, but tell the technician the clinical situation around which you need to fit it. Tell the technician the requirements for strength, bonding technique and what the underlying tooth is... then let your technician inform you as to the best restoration
7. Technicians - Keep up to date with restoration options, know the issues facing a dentist and be prepared to offer an alternative if you feel the prescription may be less than perfect.

 To discuss restoration options for your patient, please call Keith on 01707 663293 for a friendly chat.

Are Zirconia Crowns Better than PFM?

Many dental practices will charge a higher fee for Zirconia crowns to the patients as this is often seen as a 'better' or 'private' option. I disagree.

PFM is a perfectly good option and is the ideal choice in many cases.

Here is an example. This patient wanted a crown on the upper right central to replace an old crown that didn't match the surrounding dentition.

The dentist wanted a metal free crown as this was perceived to be the best, however upon attendance at the surgery I noticed a metal post and core and advices that a PFM would be the best option.

The patient and dentist were concerned, but I insisted and this was the result.

A nice crown that matches.

Metal free are, by their nature, more translucent. In situations with natural teeth underneath this is fine, but with darker teeth or root treated teeth the cores can show through.

So long as the technician uses a ceramic margin that incorporates a fluorescent shoulder porcelain the aesthetics of the crown should be fine. Also required is around 1.5-2mm of labial reduction to ensure the opaque doesn't show through.

So are zirconia crowns better than PFM?, Well yes, sometimes and in with the right cases.

To recognise this fact as a laboratory we charge the SAME for all our crowns, this way there is never a temptation to chose one option over another. We believe this provides the best result for the patient.

When would you use a PFM over a Zirconia crown? 

A Full Mouth Dental Implant Case. The patient is always right!

This week we completed a full mouth upper implant case using a cast bar and denture teeth. This was the case in the laboratory.

On the articulator

One particular issue we has was the size of the teeth; the patient had a fixation on the size of teeth and was concerned that oversized teeth would make the denture stand out and not look natural. However we went ahead and made the fixed implant bridge as requested following the try in of the teeth she asked for.

Dental Implant Bridge Palatal View

Dental Implant Bridge Labial View

Here's the finished result notice the size of the denture teeth!

It's interesting to note the difference between how the bridge looked on the articulator and then in the mouth. On the arictulator the small size of the teeth were not as apparent, but in the mouth, with the reference points of the nose and smile it is immediately clear to us as dental professionals that they are slightly too small.

But the patient is always right? And she loved them, but this could so easily have been a mistake rather than a success.

So, what lessons can we draw from this?

I think the biggest lesson is to use photographs both in the laboratory and in the surgery to communicate and share. On articulators we can easily make a mistake as we don't have the reference points of the nose and smile... but in the mouth, those small mistakes quickly come to light.

So get those photos shared.... how else can we avoid simple mistakes like getting the size of the teeth right?

Dental Implant bars - How to get them right first time...

Choosing the right type of restoration for a large full arch implant reconstruction can be difficult. Many times a denture may be the best option (perhaps to replace lost support for the face) but the patient won't accept as removable appliance! It's a difficult one to manage.

So here are our top tips for ensuring a predictable result:

1. Start, pre implant placement, with a try-in full denture WITH gum work
2. If the patient ideally wants a fixed bridge have another try-in WITHOUT gum work so you can see the emergence of the teeth
3. Use the try-in to decide if there is enough room for a bar or studs, if not enough room discuss options with us.
4. Do not proceed until the patient is happy with the try-in
5. Get us to turn the try-in in to a stent
6. Place the implants using the stent
7. Once integrated get us to make the bar with a 'snap' on bite block and final test set up
8. Once happy go through to completion

The key is the set up at the beginning, don't be tempted to guess or move too fast without getting this right. This is THE absolute KEY to predictability.

To help further with this we are running a study evening, here at the lab (a quick 15 minutes from Kings Cross Station or Jnct 22 on M25) on Tuesday 30th November 6:30pm for 2 hours.

Study Evening - The Edentulous Patient, an evening looking at CADCAM Bars and Frameworks

To book, please call the lab on 01707 663293 or book online here http://www.sbodentallaboratory.co.uk/events.html

We look forward to seeing you.

How to accurately raise the patients bite

We do lots of cosmetic smile design reconstructions in the lab, and one frequent request for occlusal rehab cases from our dentists is this "Please open the bite by 1.5mm", sounds simple huh?

Well, the problem is - where do we raise the bite from? Many replies we get to this question say "Raise the bite on the posterior teeth by 1.5 mm", but if we do this, then anterioirly the bite is raised much more.

Some times we are asked to simply raise the bite vertically by 1.5mm, but this again has big problems due to the arc of closure.

Opening the bite on an articulator is never the best solution, here is a diagram which seeks to demonstrate this further.

Notice that if the bite is opened vertically then the upper/lower relationship looks very different to if it is raised on the articulator itself due to the arc of closure... obvious really! However this is simply an exageration of what happens when we open the bite on the articulator... we have NO WAY of knowing if the arc of closure is the same as in the mouth, this means we have no way of knowing if the new opened bite will be the same new opened bite when the restorations are fitted... a recipe for disaster.

To overcome this, we recommend opening the bite in the mouth to the amount that you wish, then recording this increased vertical dimension with a squash bite. This then ensures that the opening we mount to is the same as your patient.

How have you overcome this same problem?

Technology makes implant dentures more predictable using Biomet

Over the years we have produced many, many implant cases using dentures on beams to restore the patient's teeth. Implant borne dentures on a beam solve a number of problems that fixed bridges don't:

1. They are removable which makes the case far more cleanable
2. They are far better at supporting the lip in cases of extreme bone loss
3. They can more easily be repaired

However, implant borne dentures aren't without their problems:

1. They often involve clips, attachments and/or milling which makes the cost unpredictable and often high
2. This wide use of components often means they need laser welding or soldering, this can introduce weaknesses in the design making them more prone to fracture
3. The bars are usually made of gold, while this is bio-compatible, the gold interfaces with titanium so there is a chance of some electrolytic corrosion at that interface

Modern advances in CADCAM technology have now brought together the advantages of implant beam dentures and made huge progress in removing the problems.

Using Biomet3i CAM StructSURE (r) Precision Milled Bars it is now possible to have all the benefits of a beam design with a denture AND have none of the conventional negatives. These bars are precision milled from a solid mass of industrial grade titanium which makes them incredibly strong and bio compatible.

Due to the savings made on components and manufacturing costs we are, amazingly, able to offer these bars at up to a 20% saving on our standard prices... so you get a better product at reduced price...a dental 'no brainer' really.

Biomet3i CAM StructSURE (r) Precision Milled Bars are also available in a design that is suitable for direct application of acrylic teeth, so if screw access position is good then this is a great alternative to the classic 'beam design' gold and acrylic denture.

For fixed conventional bridge work that requires composite layering (such as GC Gradia) , this is also possible using this same system using a CADCAM copy milling technique.

For further information and to discuss case management, please call Keith at the lab on 01707 663293

Save money on implant abutments & get a better product, find out how...

I’d like to personally invite you to an

Astra Atlantis Cost Effective Implant Abutment Experience

This is a perfect opportunity to find out how you can easily have:

1.     Cheaper Implant Abutments to increase profit margins

2.     More Bio Compatible Implant Abutments to provide a better product

Astra Atlantis is a revolutionary leap in technology that allows us to design implant abutments with extreme precision, to match soft tissue contours, in 3 materials - Zirconia, Titanium, Titanium/Gold Hue.

Astra Atlantis also have a unique 'Gemini' abutment system which is 2 abutments - 1 for highly accurate soft tissue contouring during temporisation, and another exact replica that is used for final restoration production. This technique saves time and creates a far better aesthetic result.

The evening will include 2 brief presentations, 1 from Keith Shrubb (Implant Director at SBO) and Christian Flynn from Astra. Plus an extended time to truly experience the full advantages of the system and answer your questions.

Date of the Astra Atlantis Experience: 13^th May 2010

Start time: 1830

Venue: SBO Dental Laboratory

Cost: £0

If you restore implants, want to save money AND want a better product then you need to book to come on this Astra Atlantis Experience to find out how to make the most of this amazing system in your practice.

Places are limited as we have a small friendly lab, so please book early to avoid missing out. Simply reply to this emai/blog with your practice details and I will add you to our list:

Name: 

Address: 

Phone number:

Number of place to book:

Alternatively call Mark on 01707 663293 or print and fax this to 01707 662092

I really look forward to seeing you,