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interest in unobtrusive and invisible dentalreplacements without clasps iscontinuously rising. After all, who wantsold-fashioned fixtures smiling frombetween young lips to represent their‘smile as the mirror of the soul’?

In Germany, this need is met usingprecision connecting elements and acombination of permanent andremovable dentures. These combinationprosthetics provide a very comfortableand aesthetic solution, particularly wherethe remaining natural teeth still provide astable foundation.

Combined dental replacement is generallyapplied when a completely fixedreplacement such as an implant is notfeasible and can also be, in part, for costreasons or when a pure bridgeconstruction becomes too expensive.

Tooth replacement is generally achievedusing partial dentures and fixed orremovable bridges. These are attached tothe columns of the remaining teeth usinga variety of available methods.

Patients in other Europeancountries are increasinglyconscious of the aestheticpotential, practicality and costeffectiveness of precisionconnecting elements, such astelescopic crowns andattachments. Whilst relativelyunknown in the UK, themethods are within the reachof UK dental practitioners withrecourse to good dentaltechnicians, and this articlegives an illustrated overview ofthe basic principles of thesetechniques.

‘Do I really need those uglyclasps with my new teeth?’

These or similar patient thoughts areprobably familiar to you as apractitioner. Today’s patient puts an

increasing value on their health andappearance in the pursuit of beauty andyouth with an increasing range of servicessuch as Botox, aromatherapy andAyurveda at their disposal. This includesdental treatment, and consequently,

by Ulrich Heker, Owner-manager of TEETH‘R’US

■ No clasps, please!

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Not all patients can afford to proceed withimplant restorations or cosmeticmakeovers and this is where precisionmilled removable dentures are highlyapplicable. This is in no way an all ornothing option as the greatestopportunities for treating almost toothlessjaws arise when combining implants andprecision connecting elements.

The precision connecting elements dealtwith in this article include all constructswhich are prepared using precisionmilling. This is achieved by using agenerally cylindrical mill which is capableof producing absolutely parallel surfaces,grooves and cavities.

Precision connecting elements can bedivided into four major categories asfollows:■ telescopic crowns■ attachments ■ bar connectors■ bolt prosthesis e.g. key slide dentures

or swing-lock dentures

Telescopic crownsAs a telescopic crown always consists oftwo parts, it is also referred to as a doublecrown. On the one side there is thebonded primary or inner telescope crownand the removable outer telescope thatinterlocks with it. Telescope crowns havebecome a standard in most Europeancountries.

For the restoration of a set of teethdisplaying a wide gap, their advantage liesin the problem-free enlargement of thereplacement dentures. It is also eminentlysuitable if one of the pillar teeth has beenremoved. However, the technique requiresa high standard of preparation andprocessing, both by the dentist and thedental laboratory. A disadvantage of thetelescope crown is that it can appear a bit

clumsy and bulky due to its structure.Viewed externally, this form of prosthesisis indistinguishable from a full prosthesisbut has the benefit of secure attachmentand increased bearer confidence.Next to attachments, telescopic crowns

are standard in Germany, Switzerlandand Scandinavia for the treatment oflarge dental gaps with a prosthesis.

Attachments If single teeth are missing and toothimplants are out of the question,removable dentures are often used. Inthis context the so-called attachment isapplied. This is a mounting or mountingelement which serves as a connectionbetween the remaining teeth and/or

single, crowned teeth, the so-calledanchor teeth or abutment teeth.

Intracoronal attachmentsIntracoronal attachments are fitted into anabutment tooth. Because the load orforce of the attachment is distributedpredominantly along the longitudinaltooth axis (1), they can be sitedconveniently throughout the jaw.Intracoronal attachments require a largersacrifice of dental material (1); however,as the dental replacement is attacheddirectly to the crown, there are no nicheswhere debris or dirt can accumulate (2).

Extracoronal attachmentsExtracoronal attachments have fittings to

Fig. 3: Typical attachment situation with interlocked crowns and precision milled rest for stress breaker

Fig. 2: Telescope in situ

the tooth exterior. The loss of dentalsubstance during preparation is far less asthe important components are situatedon the exterior of the crown.

This does, however, mean that the line offorce or load is not along the tooth axis. Afurther disadvantage with extracoronalattachments is, for example, that cleaningis made more difficult for the patient dueto projecting elements.

Intercoronal attachmentsHere, the precision elements required forthe attachment of the denture are placedinterdentally between two or moreprimary interlocked tooth columns. Again,this complicates care of the interdentalarea between the connected crowns (1).All these attachment variants can bepurchased either off the shelf or,preferably, individually tailored by a gooddental laboratory.

In order to avoid detrimental forces onthe sometimes-delicate attachments, theyshould always be used in combinationwith stress breakers.

RSS attachments RSS attachments (a form of double-shouldered attachment known as Rillen-

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Schulter-Geschiebe or RSS-Geschiebe inGerman or groove-shoulder attachmentby Bego 2001) are prepared in a similarmanner to bonded crowns.

Horseshoe-shaped elements are attachedto the oral side of the crowns (hidingthem from view) to which the matchinginterlocking denture with mirroredelements can attach.

They require less loss of tooth materialthan telescopic crowns and give a betteraesthetic, within the limitations of asmaller element surface area and lowerstability.

The pros and cons of bespokeand off-the-shelf attachments: They are comparable, where the bespokeattachments are often more secure dueto the precision manufacture and choiceof materials.

Because of the mechanical burdenthrough rotational and tilting forces, thereis a risk of deformation and breakage.

Bar connectorsBar connectors are primarily seen aslocking and, therefore, stabilisingelements. They are frequently used incombination with implants. The maindisadvantage of the bar connector is thedifficulty in cleaning and thus anincreased likelihood of inflammation ofthe gingival tissue.

Bar connectors also require more spaceand this provides the dental technicianwith additional challenges (1, 2, 3). Theflexibility for future expansion oradaptation of the prosthesis is also limitedwhen compared to telescopicattachments (1).

Bolt or key slides An ideal retaining element is theindividually produced or ready-madeswinging hinge.

Fig. 4: Stress breaker and the female part of an attachment seen from below

Fig. 5: Prefabricated bolt mechanism Degusave

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It enables friction-free insertion andremoval of the denture. In the lockedsetting the detachable denture section isfixed securely using a swinging hinge.

The advantage of the bolt or key slideprosthesis is the pressure-less attachment,similar to an interlock, of the prosthesis tothe pillar teeth. These are consequentlynot exposed to damaging forces duringthe insertion and removal of theprosthesis.

The disadvantage is the elaborateconstruction and the frequent stericproblems for the placement of the bolt.Additionally, the bolt requires considerablemanual dexterity on behalf of the patient!

ConclusionThis article provides an overview of awide variety of European answers toproviding cost-effective and aestheticsolutions for patients using precisionconnecting elements. They bridge the gapbetween conventional dentures and pureimplant solutions and give the dentalpractitioner a wider toolkit to matchindividual circumstances, taking intoaccount not only the physical oralenvironment of each patient but also theirfinancial and aesthetic aspirations.

About Ulrich Heker

Ulrich is the owner-manager of UlrichHeker Dental Laboratory, founded in 1996with the strap line ‘TEETH ‘R’ US’. As aqualified master craftsman (GermanMaster Dental Technician) since 1991, hehas over 26 years’ experience both at thebench 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:

■ Ulrich HekerD-45130 Essen Corneliastr. 17, Tel: +49201 797 955,www.german-smile.info,Ulrich@Teethrus.de

The author – Ulrich Heker

‘Excellence is the result ofalways striving to do better’

– Pat Riley

Fig. 6: Groove-shoulderattachment

Each type of precision connectingelement – telescopic, attachments, barsand bolts or key slides – has its ownunique features in preparation andapplication. It is my intention to considerthese in more detail individually in futurearticles if the reader is interested.

The manufacture of a perfect prosthesis,one that is not perceived as a foreignbody in the mouth by the patient,requires great mechanical skill from adentist and dental technician. Only theclose interaction by both specialistsdelivers the desired result for the patient.

References1. Stüttgen, U., Hupfauf, L.: Kombiniert

festsitzend – abnehmbarer Zahnersatz.In: Horch, H.-H., Hupfauf, L., Ketterl, W.,Schmuth, G., (Hrsg.): Praxis derZahnheilkunde 6 (Teilprothesen), 2.Aufl.Urban & Schwarzenberg, München –Wien - Baltimore 1988.

2. Jüde, H.D., Kühl, W., Roßbach, A.:Einführung in die zahnärztliche Prothetik.5.Aufl. Deutscher Ärzte- Verlag, Köln1996.

3. Lenz, P., Gernet, W.: EinseitigeFreiendprothesen mit Konuskronen.Zahnärztl Welt 87, 1069 (1978).

To see more images relating to this and future articles, visit:http://www.german-smile.info/combinedcare/combinedcare_02.htm