12 february 2013
diamondcrowns
■ A diamond in the crown Introduction
Planning
Master dental technician Ulrich Heker describes the unusual process of adding a diamond insert into a top front tooth crown.
There was a question about the mount. For example, with a Tiffany mount of a diamond solitaire, the jewel is held by six claws, a form of chaton mount. However, chatons normally used in jewellery making would not be suitable here owing to the sharp edges of their claws and the difficulty in fixing to the piece; the danger of injury and impaction would be too great.
The proposal When I received a query from a longstanding dentist client for an upper front tooth crown, the first thought was, no problem! There was, however, a twist. Could we incorporate a diamond, which the patient had inherited from his mother, as he did not wear rings? Furthermore, the patient had a very clear idea of the final appearance of the crown and had even made a design to show exactly where the stone should sit on the crown. I could not refuse the challenge!
The brief To make a root post and core with a crown on 12 – including a gemstone of unknown form (see below) and following the patient’s specifications – so far, so good! This was how the case was presented by Martin Sulo’s dental practice in Norwich: A 70-year-old male patient referred himself to our practice for the restoration of a missing upper lateral incisor. The clinical examination showed the residual tooth structure of the fractured upper lateral incisor had a horizontal fracture line at the gingival level. Radiological examination revealed the presence of a root filling with no apparent periapical pathology. Although the patient came into the practice with a clear idea of having this tooth removed and replaced by an implant-supported crown, after discussing the matter, he agreed to have the tooth restored by a conventional crown, supported by post and core. He also had a special request: to incorporate the diamond gemstone from his late mother’s ring. the
technologist
Conversations with the jeweller determined that the labial surface of the crown should be a solid, circular gold plate. After casting, a hollow matching the base of the gem would be drilled to accommodate the diamond – without perforating the crown. As adhesives cannot be guaranteed to give a long-lasting hold in the damp environment of the mouth, the diamond would be held in place by moulding the edges of the gold plate into an annulus around the top of the stone. The dentist originally wanted to use a ceramic mount. On discussion, we decided this was too risky a strategy. Whilst a genuine diamond could have survived the firing temperature of approximately 950°C undamaged, the impact of the riveting hammer during the setting of the stone was likely to damage the finished ceramic. We therefore chose a composite mount. This would enable us
The post
to mould the crown after setting the stone in order to exclude any mechanical damage. After consultation with the jeweller, we decided to use a ductile (soft) alloy for the plate, containing as much gold as possible.
Post and core construction The post was prepared on receipt of the casts. In this position, the construction of the post was very convenient. Had it been a vital tooth we might possibly have had problems with positioning. Here we were guaranteed the optimal amount of available space for the construction of the crown, together with its recessed stone.
Preparation of the crown The first step was the preparation of a ‘wax up’, in order to establish the outer shape of the tooth. This ‘wax up’ was then further reduced so that only a circular portion of the exterior surface remained where the stone was to be set. The diameter was approximately 2 mm larger than the stone. After casting and subsequent preparation, the gold plate was again checked for its axial and labial alignment. Centring was done afterwards.
february 2013 13
diamondcrowns This was large enough for the stone to fit completely into the hollow, yet still preserving a small border to seal the edges.
Done
The jeweller drilled out ‌
materials & equipment
Fixed for better handling
Finally, to help the jeweller secure the crown, a plastic stump was fitted. This provided a base to hold the piece firmly in place under the drill. The prepared crown was then sent to the jeweller so the stone could be set.
core verifiable CPD
The crown, ready for the jeweller
After repeated adjustments, the stone was finally inserted into the crown for the last time. The diamond was held exactly in place by moulding the protruding edges around the rim (ductile metal). For the diamond to have a greater impact, a narrow ring of gold was to remain around the gemstone.
Bonding with Rocatec
In the jeweller’s workshop The jeweller drilled out the recess for the diamond with great care (i.e. without perforating the external wall of the crown). Opaquer
Shading with in:joy ( Dentsply)
the
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14 february 2013
diamondcrowns
■ Video: Skype: martinsulo ■ www.bdp.thedrift@yahoo.co.uk Let’s rock
Feedback
Once the stone had been set, and the crown had found its way back to the laboratory, the final crucial step was to mount it with a suitable composite, in this instance in:joy from Degudent. The framework was conditioned with Espe Rocatec. Great care was taken to ensure that no opaque material covered the outer edge of the gold ring surrounding the stone, as this would have left an unsightly white line on the edge of the setting. After a final finishing polish, the job was done and sent off to the customer.
A few days later I received a call. The result? A happy patient, a happy dentist and a happy (and very relieved) dental technician!
Summary Even after working in the job for many years, orders like this one continually give us new challenges. One ‘small’ change in the process of producing a simply dazzling crown can, as in this case, lead you to a completely new way of thinking. Who said dental technology was boring!
Ulrich Heker is the owner-manager of Ulrich Heker Dental Laboratory founded in 1996 with the strap line TEETH ‘R’ US. As a qualified master craftsman (German Master Dental Technician) since 1991, he has over 26 years’ experience both at the bench and in running a successful business. Ulrich lives in Mülheim on the river Ruhr and is an accomplished ‘western-style’ rider in his spare time. Ulrich is fluent in English and can easily be contacted at: ■ Dentallabor Ulrich Heker D-45130 Essen Corneliastr. 17. ■ T: +49 201 797 955, ■ M: +44 7922 458299 ■ Video Skype : teeth.are.us ■ Web: http://www.german-smile.info, http://www.dentallabor-heker.de ■ E: ulrich@teethrus.de
A happy patient/team. Insert: In situ
the
technologist
materials & equipment
Mounting and completion
core verifiable CPD
About the authors Martin Sulo is the owner and principal dentist of Botesdale Dental Practice in Suffolk. He qualified in 1998 in the Czech Republic. He is interested in all aspects of modern dentistry, especially in fixed prosthodontics.