the technologist - diamonds are a boy's best friend

technologistthe

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diamondcrowns

Introduction

Master dental technicianUlrich Heker describes theunusual process of adding adiamond insert into a topfront tooth crown.

The proposalWhen I received a query from a long-standing dentist client for an upper fronttooth crown, the first thought was, noproblem! There was, however, a twist.Could we incorporate a diamond, whichthe patient had inherited from his mother,as he did not wear rings? Furthermore,the patient had a very clear idea of thefinal appearance of the crown and hadeven made a design to show exactlywhere the stone should sit on the crown.I could not refuse the challenge!

The briefTo make a root post and core with a crownon 12 – including a gemstone of unknownform (see below) and following thepatient’s specifications – so far, so good!

This was how the case was presented byMartin Sulo’s dental practice in Norwich:A 70-year-old male patient referred himselfto our practice for the restoration of amissing upper lateral incisor. The clinicalexamination showed the residual toothstructure of the fractured upper lateralincisor had a horizontal fracture line at thegingival level. Radiological examinationrevealed the presence of a root filling withno apparent periapical pathology.

Although the patient came into thepractice with a clear idea of having thistooth removed and replaced by animplant-supported crown, after discussingthe matter, he agreed to have the toothrestored by a conventional crown,supported by post and core.He also had a special request: toincorporate the diamond gemstone fromhis late mother’s ring.

PlanningThere was a question about the mount.For example, with a Tiffany mount of adiamond solitaire, the jewel is held by sixclaws, a form of chaton mount. However,chatons normally used in jewellery makingwould not be suitable here owing to thesharp edges of their claws and the difficultyin fixing to the piece; the danger of injuryand impaction would be too great.

Conversations with the jeweller determinedthat the labial surface of the crown shouldbe a solid, circular gold plate. After casting,a hollow matching the base of the gemwould be drilled to accommodate thediamond – without perforating the crown.As adhesives cannot be guaranteed to givea long-lasting hold in the dampenvironment of the mouth, the diamondwould be held in place by moulding theedges of the gold plate into an annulusaround the top of the stone.

The dentist originally wanted to use aceramic mount. On discussion, wedecided this was too risky a strategy.Whilst a genuine diamond could havesurvived the firing temperature ofapproximately 950°C undamaged, theimpact of the riveting hammer during thesetting of the stone was likely to damagethe finished ceramic. We therefore chosea composite mount. This would enable us

to mould the crown after setting thestone in order to exclude any mechanicaldamage. After consultation with thejeweller, we decided to use a ductile(soft) alloy for the plate, containing asmuch gold as possible.

Post and core constructionThe post was prepared on receipt of thecasts. In this position, the construction ofthe post was very convenient. Had it beena vital tooth we might possibly have hadproblems with positioning. Here we wereguaranteed the optimal amount ofavailable space for the construction of thecrown, together with its recessed stone.

Preparation of the crown The first step was the preparation of a‘wax up’, in order to establish the outershape of the tooth.

This ‘wax up’ was then further reduced sothat only a circular portion of the exteriorsurface remained where the stone was tobe set. The diameter was approximately 2 mm larger than the stone.

After casting and subsequent preparation,the gold plate was again checked for itsaxial and labial alignment. Centring wasdone afterwards.

The post

■ A diamond in the crown

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Finally, to help the jeweller secure thecrown, a plastic stump was fitted. Thisprovided a base to hold the piece firmlyin place under the drill. The preparedcrown was then sent to the jeweller sothe stone could be set.

In the jeweller’s workshopThe jeweller drilled out the recess for thediamond with great care (i.e. withoutperforating the external wall of the crown).

This was large enough for the stone to fitcompletely into the hollow, yet stillpreserving a small border to seal the edges.

After repeated adjustments, the stonewas finally inserted into the crown forthe last time. The diamond was heldexactly in place by moulding theprotruding edges around the rim (ductilemetal). For the diamond to have agreater impact, a narrow ring of gold wasto remain around the gemstone.

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The crown, ready for the jeweller

Fixed for better handling

The jeweller drilled out …

Done

Bonding with Rocatec

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Shading with in:joy ( Dentsply)

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Mounting and completion Once the stone had been set, and thecrown had found its way back to thelaboratory, the final crucial step was tomount it with a suitable composite, in thisinstance in:joy from Degudent. Theframework was conditioned with EspeRocatec. Great care was taken to ensurethat no opaque material covered the outeredge of the gold ring surrounding thestone, as this would have left an unsightlywhite line on the edge of the setting. Aftera final finishing polish, the job was doneand sent off to the customer.

FeedbackA few days later I received a call. Theresult? A happy patient, a happy dentistand a happy (and very relieved) dentaltechnician!

SummaryEven after working in the job for manyyears, orders like this one continually giveus new challenges. One ‘small’ change inthe process of producing a simplydazzling crown can, as in this case, leadyou to a completely new way of thinking.Who said dental technology was boring!

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About the authorsMartin Sulo is the owner and principaldentist of Botesdale Dental Practice inSuffolk. He qualified in 1998 in the CzechRepublic. He is interested in all aspectsof modern dentistry, especially in fixedprosthodontics.

■ Video: Skype: martinsulo■ www.bdp.thedrift@yahoo.co.uk

Ulrich Heker is the owner-manager ofUlrich Heker Dental Laboratory foundedin 1996 with the strap line TEETH ‘R’ US.As a qualified master craftsman (GermanMaster Dental Technician) since 1991, he has over 26 years’ experience both atthe bench and in running a successfulbusiness. Ulrich lives in Mülheim on theriver Ruhr and is an accomplished‘western-style’ rider in his spare time.Ulrich is fluent in English and can easilybe contacted at:

■ Dentallabor Ulrich HekerD-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

Let’s rock

A happy patient/team. Insert: In situ