A telescope implant treatment: by Ulrich Heker DTM

Or “When black OR white are not the only solutions”

As a dentist, you are often faced with situations where black or white, prosthesis or implant, are not the only options. This is a case study of a telescope implant treatment (Kennedy Class 1) in the upper jaw of a female patient. Ulrich Heker (Master Dental Technician) describes the treatment of a UK patient with a completely detachable prosthesis based on telescopic implants, combining the best of both technologies to provide an optimal solution for the client, at a reasonable cost.

Case history

The patient presented a unique challenge for the dentist. The 55 year old female had worn a classical gold/gold telescope prosthesis for many years. The original elegant work had evolved over the years through repeated extensions and relining. Finally, with a plate completely covering the palate, it had mutated into a full denture.

The patient did not want to wear a full denture under any circumstance, so now implants appeared to be the only alternative.

However, from an oral surgical point of view, both sides were unsuitable for implants due to the lack of bone material. The patient had also rejected the necessary but expensive augmentation of the molar areas. Individual attachments were also out of the question as the patient wanted a palate-free prosthetic solution.

After thorough consideration, the decision fell in favour of a combination of implants with individual abutments and a detachable, bar-free telescope prosthesis.

This was the situation:

(T=telescope with. implant; x= missing)

Technique

Planning

The cost would have been exorbitant if I had followed the conventional route of using high- (gold/platinum content) or semi-precious alloy to make all the inner and outer parts. I estimated it would need 25 - 30 grams of high concentration gold or gold-reduced alloy, such as Degulor® MO, to guarantee sufficient material thickness/strength.

The alternative consisted of primary parts made from non precious alloy (NPM), capped with 0.2 - 0.3 mm of gold as secondary crowns. These would then be bonded to a CrCo tertiary structure using two-component cement.

CrCo also allows a less bulky construction than using gold alloys, whilst also reducing the need for soldered connections. As there were to be no transversal connectors, the design of the tertiary structure was critical.

The patient was fitted with Regular Neck (RN) implants. After a successful healing-in, the RN implants were exposed and a pick-up impression taken with an individual tray over the impression posts. The author recommends using an open special tray which is rigid, to allow access to the retaining screws of the pick-up impression copings.

Fig. 2 Situation after exposure

Fig. 1 RN Variobase

After preparation of the gum mask, measurements could be taken from the master model with laboratory implants.

The RN® Burn-out copings were attached to the screwed-in bases and adjusted to length as necessary in the Articulator.

Fig.3 Positioned and shortened RN Burn -out copings within gum mask

Fig.4 Finished wax milling

The primary parts were milled on RN Burn-out copings in wax and cast in non-precious alloy . The secondary parts were sandblasted and carefully attached to a Straumann RN Variobase®. The units were then screwed into the master model, milled and polished.

Fig.5 Individual telescope Abutments

Fig.6 Modelling of the secondary caps in Pattern Resin®

Fitting of the primary parts with a pick-up impression is not necessary at this stage, so modelling of the secondary crowns could be started straight after milling. In order to avoid confusion over the Abutments, a base was made from light curing acrylic to act as a positioning reference.

Fig. 7 Key to help avoid rotation errors of the primary parts in Situ

milling of the plastic caps significantly reduced the time spent on metalwork.

Fig.8 Milling the Pattern Resin ®caps

If you look closely (under a microscope) at the friction surfaces in conventional telescopic work after a certain period time, you nearly always see narrow striations and traces of wear on both primary and secondary crowns. With

Galvano crowns, this can quickly lead to a loss of adhesion (as it is not really a friction with galvano crowns), which cannot be restored (?).

The combination of materials used here has the following advantages:

• Signs of wear in the primary parts are completely prevented owing to the hardness of the non-precious alloy (NEM).

• Primary parts in non-precious alloy (NEM) can be made much thinner than when using precious alloy. (The fact that the primary parts are coloured silver instead of gold should be discussed with the patient beforehand).

• The consistent, highly polished finish of primary parts made from NEM, prevents „scratching" of the inner surfaces of the secondary parts. Here the primary part works rather like a non-abrasive polisher, as seen in the broad, glossy friction surfaces.

• Production of the secondary parts is less expensive. • Longer lasting friction when compared to Galvano

crowns. • Secondary parts can be re-worked and re-milled safely,

as they are substantially more stable than Galvano crowns.

Fig.9 Secondary crowns finished for final milling

The components were subsequently fixed to the primary parts and milled again.

The final milling creates parallel external surfaces, important for the production of the metal frame. Using parallel guides also meant there was no danger of unexpectedly perforating the secondary parts.

The coarse milling cutter used at this stage gave the desired amount of abrasion whilst also creating an ideal adhesive surface.

Fig.10 Parallel milling and simultaneous thinning of the secondary crowns

For fitting, a 1.5mm Erkolen®- foil was thermoformed over the complete work for positioning. Following small corrections, the try-in was secured using a matrix.

Fig.10 Caps on the model after milling

The tertiary structure

Fig.11 Blocked master model (fully relineable)

Care should be taken when modelling, to achieve the optimum distribution of material. Thin in the Labial region, where there is never sufficient room and thicker in the oral

region to afford the necessary strength. The metal frame was made such that it could be completely relined in the future, thus avoiding pressure points.

Fig.12 Assessment of available space using silicone key

As per the patient's wishes, we were able to avoid any transversal connectors..

Another 'try-in' of all the metal pieces took place: The base, with the glued primary parts and keys, the Gold caps on top and, finally, the CrCo base.

The model cast showed an identical fit on the master model and in the mouth of the patient. It was now ready for completion.

Fig.13 views of the finished Tertiary construction

Back in the laboratory, finishing was carried out in the conventional way, after all exterior surfaces had been coated with Silane and covered with opaquer. Finally, all adhesive surfaces were prepared by using Aluminum Oxide 100 micron and degreased prior to intra-or'al cementing.

Table 1 Schematic of the entire construction from implant to CrCo tertiary Structure

a RN® Implant

b RN Variobase™ Abutment

c Primary Crown

d RN Burn-out coping

e Secondary crown, gold cap

f CrCo Tertiary structure

The technician’s role was done.

A note on the final fitting:

In order to prevent stresses, the cementing (the caps with the frame) should only happen intraorally in pairs. Beginning at the distal end, the secondary crowns were cemented in in opposing pairs. The remaining 4 and/or 2 stayed on the primary parts.

Fig.14 Situation before cementing

Fig.15 Basal view before cementing

Fig.17 Basal view before cementing.

What the patient thought:

„My new denture is pleasant to wear. I am particularly happy that I no longer have bars on the roof of my mouth - that always bothered me about my old denture. I believe that this result was only made possible by the close co-operation between my dentist and the dental technician; from the initial planning through to completion. “

Fig. 16 A long way to a happy patient

What the dentist thought:

The entire prosthetic treatment could be done with relatively few appointments. Trying-in was problem-free, although time-consuming as each time the Abutments had to be set up and removed. A suitable key can save a lot of 'trial and error'

The acclimatisation phase was extremely short for the patient as she had already had a telescope denture in the past. The absolute rigidity of teeth implants firmly anchored in the bone, compared with flexibly attached natural teeth, felt unusual at first. It required an even more precise insertion and removal of the prosthesis.

Conclusion

This method of implant treatment for edentulous patients offers a really good, stable, yet unobtrusive solution. Complex surgical interference with augmentation can also be avoided. Clearly, it is possible to treat difficult cases in a truly effective way (here: Kennedy Class I: as „Removable bridge “), by using implants and telescopes together.

“Black or white are not the only solutions”.

About the author

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 . Ulrich is fluent in English and can be contacted at:

Ulrich Heker D-45130 Essen Corneliastr. 17, T: +49 201 797 955, Video skype: TEETH ARE US http://www.german-smile.info, ulrich@teethrus.de