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Retentive systems for implant-borne hybrid dentures


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Retentive systems for implant-borne hybrid dentures

  1. 1. Retentive systems for implant-borne hybrid PROSTHETICS denturesDENTAL IMPLANT SYSTEM
  2. 2. I M P O R TA N T N O T E SDisclaimer of liability Description of the symbols on labels and instructionsThe ITI dental implant is part of an overall concept and for usemay only be used in conjunction with the associatedoriginal components and instruments according to Institut LOT Lot/batch numberStraumann AG’s instructions and recommendations.Use of products made by third parties in conjunction with REF Article numberthe ITI® DENTAL IMPLANT SYSTEM will void any warrantyor other obligation, express or implied, of Straumann. STERILE R Sterile by gamma irradiationInstructions as to application of our products take placeverbally, in writing, by electronic media or in hands-ontrainings corresponding to state of the art at the time of STERILE Nonsterileintroduction of the product.The user of ITI products has the duty to determine whetheror not any product is suitable for the particular patient Do not use on patientsand circumstances. Straumann disclaims any liability,express or implied, and shall have no responsibility forany direct, indirect, punitive or other damages, arising Do not reuseout of or in connection with any errors in professionaljudgment or practice in the use or installation of ITIproducts. As a general rule, our products must be secured Refer to instructions for useagainst aspiration when used intra-orally.The user is also obliged to study the latest developments of Use before expiry datethe ITI® DENTAL IMPLANT SYSTEM and their applicationsregularly.Please noteThe descriptions given are insufficient to allow immediateuse of the ITI® DENTAL IMPLANT SYSTEM. Guidance in Colored warning labelsthe handling of these instruments by a doctor experiencedin their use is strongly recommended. YELLOW ➡ CAUTION: In case of danger or unsafe handling, which might causeValidity slight bodily injury or damageUpon publication of this brochure, all previous versions to property.are superseded. ORANGE ➡ WARNING: In case of danger whichAvailability might cause severe bodily injuryNot all products listed in this brochure are available in or death.all countries. RED ➡ DANGER: In case of danger which mayDelivery cause severe bodily injury orFederal law restricts these devices to sale by or on the death, immediately.order of a dentist or a physician. Definition SLA: Sand-blasted, Large grit,Units per package Acid-etchedUnless stated otherwise, there is one unit in each package.DocumentationYou can obtain detailed instructions on the ITI® DENTALIMPLANT SYSTEM from your Straumann representative.Copyright and trademarksStraumann documents may not be reprinted or published,in whole or part, without the written authorization ofInstitut Straumann AG. ITI® DENTAL IMPLANT SYSTEM,synOcta®, Octasystem® and ITI TE ® are registeredtrademarks of Institut Straumann AG, Switzerland.
  3. 3. ContentsInstructions for dentists anddental techniciansTable of contents■ Planning principles and recall appointments 2Bar-borne restorations 3■ Introduction 3■ Fabrication of an implant-borne bar in the lower jaw using the 6 synOcta® prosthetics system■ Fabrication of cast and laser-welded bars 18■ Fabrication of the final bar restoration with metal reinforcement 22■ Modification of an existing full lower denture in an implant/ 24 bar-borne hybrid denture■ Relining of an implant-borne bar denture 26Retentive anchors 29■ Introduction 30■ Fabrication of a new full lower denture with metal reinforcement 31 and two gold matrices■ Fabrication of a new full lower denture with metal reinforcement 36 and two titanium matrices■ Modification of an existing full lower denture in an 42 implant-borne retentive anchor denture■ Relining of an implant-borne retentive anchor denture 44Magnets 49■ Introduction 50■ Fabrication of a full lower denture with two magnets 53■ Modification of an existing full lower denture on an 58 implant-borne magnet denture■ Relining of an implant-borne magnetic denture 60 1
  4. 4. Planning Planning principles Recall appointments Implant-borne full dentures require Hybrid dentures with resilient thorough planning of the surgical retention units must be examined and technical procedures. The at intervals of approximately number and positions of the 3 months to ensure harmful implants as well as the design of excursions of the denture are the denture and occlusion should eliminated in their early stages take account of the anatomical, (possible methods: relining, functional and hygienic aspects. activating/replacing the matrix, The static/dynamic conditions checking the occlusion). govern the selection of the In cases of poor oral hygiene, the retentive units (Besimo, 1993). patient should undergo thorough Magnet and bar retention systems scaling and polishing, as well as for implant-borne lower hybrid re-instruction and motivation to dentures subject the implant maintain the necessary high level abutments to the lowest stress of oral hygiene. If the patient is (Jäger and Wirz, 1993). co-operative, the interval between check-ups can be increased.2
  5. 5. Bar-borne restorations Bar-borne restorations Introduction The functions of a bar restoration: ■ Stabilisation and primary splinting of implants ■ Countering the forces that would dislodge the denture ■ Distribution of shear forces ■ Resilience compensation through degrees of freedom Description/ Functioning Most common types of bar: Dolder® bar (egg-shaped cross- section), normal and mini versions: The Dolder® bar is a retention unit allowing three degrees of freedom (translateral and rotary move- ments). Dolder® bar attachment, “U”-shaped cross-section: The bar attachment is a rigid retentive unit with no rotational freedom. Round bar: The round bar is a retention unit permitting only one degree of freedom (translateral movements).1 Dolder® registered trademark from Prof. Eugen Dolder, former director, School of Dentistry, University of Zurich 3
  6. 6. Bar-borne restorations The following guidelines must absolutely be heeded when fabricating implant-borne hybrid dentures: Freedom: “If riders are placed on more than one bar segments, the denture is retained, but has no degree of space freedom regardless of the cross-section of the bar.” (Wirz, 1994) ”If a rider is placed on the anterior-most bar segment only, a round bar creates 1 degree of space freedom, an egg-shaped cross-section 3 degrees of freedom and a bar attachment (or milled bar) no freedom.” (Wirz, 1994) Bar positioning: The anterior bar is positioned perpendicular to the median line of the two halves of the alveolar ridge. (Wirz, 1994) The bar must be horizontal – even if the ridge varies in height. The bar must never be allowed to slope as this would impede the correct functioning of the bar attachment and create undesirable horizontal forces. (Wirz, 1994)4
  7. 7. Bar-borne restorationsPlanning the bar When used in the linear and front areas only, the Dolder bar joint,restoration with its three different degreesEarly loading of the implant or of space freedom, loads the abut-fabrication of the restoration once ments least of all regardlessthe healing period has elapsed of the number of abutments. If, however, the abutments are“If full lower dentures are to be spaced regularly in the anteriorretained on ITI Dental implants, the region, and the denture is retainedfollowing basic principle applies: on all bar segments using severalFour implants are required if after riders – regardless of the cross-implantation, for any reason section of the bar – the dynamicswhatsoever, the implant abutments of the denture are lost completely.have to be loaded with a denture This is a purely rigid type ofbefore osseointegration has been retention with no freedom whatso-completed. This is often necessary ever. If we are able to allow atwhen one-part implants are used, least three months for osseointe-as the conditions of the temporary gration of two-part implants –restoration are usually very which should usually be the case –unfavourable. In such cases, it is we may limit ourselves to twoimperative that the four implants relatively short implant abutments,are splinted with a bar. assuming that the masticatory forces are absorbed by the denture bed and not by the implant site.” (Wirz, 1994). 5
  8. 8. Bar-borne restorations Fabrication of an implant-borne bar in the lower jaw using the synOcta® prosthetics system “Patient” – initial situation: Edentulous lower jaw, with 4 two- part ITI Dental implants in positions 44–34. Important: The synOcta® abut- ments can be used only with the implants with art. Nos. 043.xxxS. Impression-taking with synOcta® prosthetics: Two versions are available for the impression procedure: the “snap-on” version and the “screw- retained” version. The snap-on version can be regarded as the standard and can be used in the majority of cases. The screw- retained version is particularly indicated where the implant shoulder lies very deep. In order to prevent any risk of confusion, the transfer system is colour-coded. The positioning cylinder, analog and screw- retained impression cap are colour-coded red in the synOcta®6 prosthetic system.
  9. 9. Bar-borne restorations The octagon on the positioningA. “Snap-on” impres- cylinder must be aligned with the internal octagon on the implantsion procedure and be inserted into the impres-All parts of the transfer system are sion cap until it is flush with thesupplied non-sterile. They can be top of the impression cap.disinfected, as required, using The impression should be takenstandard commercial disinfectants using an elastomeric impressionfor plastic products. (Please follow material (polyvinylsiloxane ormanufacturers’ directions). polyether rubber).Caution: The plastic parts aredesigned for single use only.They must not be sterilised in theautoclave.To prevent damage to the plasticcomponents (loss of elasticity,embrittlement), they must beprotected from heat and light. Important: Due to its insufficient tensile strength and inadequate elastic recoil, hydrocolloid is not suitable for this application.The implant shoulder and interiormust be thoroughly cleaned priorto the impression procedure. Theimpression cap (048.017) ispushed onto the implant until the “click”shoulder clicks into place. Theimpression cap is turned gently inorder to check that it is in thecorrect position. When the cap isin the correct position, it can berotated on the implant.Important: To avoid errors duringthe impression procedure, it mustbe ensured that the shoulder andthe margin of the impression capare not damaged. 7
  10. 10. Bar-borne restorations B. “Screw-retained” impression procedure A special tray with perforations is required for this application. The implant shoulder and interior must be thoroughly cleaned prior to the impression procedure. The impression cap (048.010) is placed on the implant and is tightened with the integral posi- tioning screw. Precise positioning of the octagon of the impression cap into the octagon of the implant is important. Should only a limited amount of space be available, the occlusal aspect of the cap can be reduced by one retention ring (once the positioning screw has been removed). Important: Only the integrated screw must be used! The margin and octagon must not be damaged in order to prevent any errors during the transfer process. For this reason, the impression caps are for single use only. The impression should be taken using an elastomeric impression material (polyvinylsiloxame or polyether rubber) in accordance with the manufacturer’s directions. Once the material has set, the positioning screws are loosened, and the impression is removed. Important: Due to its insufficient tensile strength and inadequate elastic recoil, hydrocolloid is not suitable for this application. After impression-taking, the healing caps are repositioned on8 the implants.
  11. 11. Bar-borne restorationsFabricating themaster castThe “snap-on” version:The red positioning cylinder showsthe dental technician that it is thered analog that must be used. Inthe laboratory, the analog(048.124) is repositioned in theimpression, and the shoulder mustclick audibly into place.The analog must not be rotated inthe impression.The “screw-retained” version:The analog is secured in theimpression using the integralpositioning screw. The redimpression cap shows the dentaltechnician that it is the red analogthat must be used.Important: When tightening thescrew, grasp the retentive sectionof the analog in order to preventthe impression cap from rotating.This is especially important if thecap has been shortened. 9
  12. 12. Bar-borne restorations Fabricating the working master cast in the conventional way using Type 4 plaster (DIN 13911). The synOcta® abutment (048.600) is placed in the analog and aligned in the octagon. N.B.: The abutment must be positioned in the octagon before the screw is tightened. The screw is hand-tightened using the SCS screwdriver.10
  13. 13. Bar-borne restorationsFabrication of thejoint gold barThe prefabricated gold copingbar for the synOcta® prostheticssystem without an internal octagon(048.636) consists of a non-oxidising, high-melting alloy(HSL; Au 60%, Pt 19%, Pd 20%,Ir 1%; melting range 1400–1490°C). It is screwed onto theanalog/synOcta® abutment withthe 4.4 mm SCS occlusal screw(048.350V4). The gold copingis 5.6 mm high and cannot beshortened.The individual bar segments areplaced between the abutmentunits. Attention should be paid tothe space between the bar andgingiva (min. 2 mm) to facilitateadequate cleaning and so preventchanges in the mucosa.Important: To achieve a goodjoint, the gap should be as smallas possible. 11
  14. 14. Bar-borne restorations Type of join The prepared bar can now be soldered or laser-welded, as desired. A laser-assembled bar does not require soldering with non-precious ingredients and is therefore more biocompatible. Laser-welding takes place directly on the plaster model and therefore takes less work. Larger gaps are filled with wire made from the same type of material (see also page 20, Fabrication of laser- welded bars with titanium components). Soldered gold bar: The gold copings and prefabricat- ed bar segments are secured in place with a residue-free, burn-out plastic. The SCS occlusal screws must not be covered. Tip: Overwaxing of the plastic compounds ensures good access of the flame later on in the soldering investment. Once the SCS positioning screws have been loosened, the bar framework is carefully removed. Stabilisation pins (048.208V4) are available for retaining the synOcta® bar gold copings in the soldering investment and are screwed into place with the SCS positioning screws. They ensure that the gold copings are anchored accurately in the soldering investment during12 soldering.
  15. 15. Bar-borne restorationsTo prevent possible distortion ofthe bar due to uneven preheatingwith the flame, the hardenedsoldering investment is preheatedto 930–1,100° F in a preheatingfurnace.After the invested bar has beenpreheated, it is ready forsoldering. Once soldering hasbeen completed, the investmentshould be cooled to roomtemperature. The bar must be devested and cleaned in an ultrasonic bath. The oxides and soldering flux residues are then removed in an acid bath. Important: Due to the high preci- sion of the prefabricated caps, increased caution is required during polishing. Therefore, under no circumstances, should a sandblaster be used. Tip: To protect the margins, a polish protector (046.245) or an analog can be screwed on during polishing. This reduces the risk of damage to the margins. It is advisable to work under a stereo- microscope. 13
  16. 16. Bar-borne restorations It must be possible to reposition the cleaned bar without tension on the analogs, without it being secured with the SCS occlusal screws when checking its fit. Important: The SCS occlusal screws that were used for solder- ing will be extremely oxidised and must not be used to secure the bar in the mouth. The bar must be secured in place with new SCS occlusal screws. The finished synOcta® bar on the plaster model.14
  17. 17. Bar-borne restorationsInsertion of the barconstruction in themouthThe restoration is delivered to thedentist with the original abutments.The healing caps are removedand the interior of the implant isthoroughly cleaned and dried.The superstructure is removed fromthe master cast and the abutmentis unscrewed from the analog. The cleaned synOcta® abutment The SCS occlusal screws are is positioned without cement in the tightened with 15 Ncm on the internal octagon. The abutment synOcta® abutment. screw is tightened using the SCS The bar is in situ with the new SCS screwdriver, ratchet (046.119) and occlusal screws. torque control device (046.049). N.B.: The abutment must be positioned in the octagon before the screw is tightened. After osseointegration of the implants, we recommend a tightening torque of 35 Ncm when inserting the abutment screws. Torque = 35 Ncm! 15
  18. 18. Bar-borne restorations Positioning the bar matrix The matrix must make use of the entire length of the bar. This helps absorb horizontal forces better. (Wirz, 1994) Varying the retention force of the bar matrix: Only the appropriate activator/ deactivator may be used for activating/deactivating the bar matrix. ■ To activate the matrix, press its walls together with the activator. ■ To deactivate the matrix, press its walls apart with the deactivator. Activator set for all bar matrices Deactivator for Dolder bar, mini Deactivator for Dolder bar, (046.150) (046.151) standard (046.152)16
  19. 19. Bar-borne restorationsInitial situation edentulous: bar on synOcta®Type of bar: soldered/laser-welded gold barAbutments and laboratory components gold copings InstrumentsInsertion of abutmentsynOcta® abutment, 048.600 SCS screwdriver: length 15mm: 046.400 length 21mm: 046.401 length 27mm: 046.402 and/or SCS screwdriver for handpiece adapter: length 20mm: 046.410 length 26mm: 046.411 length 32mm: 046.412Impression procedureOptional: Laboratory handpiecesynOcta® impression cap with integral 046.085positioning screw 048.010 for 046.410/411/412or impression cap 048.017V4+ synOcta® positioning cylinder 048.070V4Production of master castsynOcta® analog 048.124Production of superstructuresynOcta® gold coping, bar, 048.636Dolder® bar, egg-shaped cross-section,mini, 048.411Dolder® bar matrix, mini, 048.413Dolder® bar, egg-shaped cross-section,standard, 048.412Dolder® bar matrix, standard, 048.414Stabilisation pin, 048.208V4SCS Occlusal screw, 048.350V4Insertion of final restorationSCS Occlusal screw, 048.350V4 Activator set, 046.150 Deactivator, mini, 046.151 Deactivator, standard, 046.152 17
  20. 20. Bar-borne restorations Fabrication of cast and laser-welded bars Fabrication of bars using the one-piece casting method As an alternative to the laser- welded or soldered gold bars, the dental technician now has a choice of synOcta® plastic coping, bar (048.660), and the Dolder bar variants standard (048.460) and mini (048.461) in burn-out plastic for the fabrication of a cast titanium bar (Wirz, 1997 and Wirz et al., 1999). The standard and mini titanium bar matrices which fit the titanium bar (from left to right). The bar, composed of plastic parts and prepared for embedding.18 The bar cast from pure titanium.
  21. 21. Bar-borne restorationsArt. No. Article Dimension Material048.660 synOcta® plastic coping Height 13.3 mm, Burn-out plastic bridge/bar shortenable048.460 Plastic bar, egg-shaped Height 3.0 mm Burn-out plastic cross-section, standard Length 80.0 mm048.461 Plastic bar, egg-shaped Height 2.3 mm Burn-out plastic cross-section, mini Length 80.0 mm048.470 Titanium bar matrix Height 4.5 mm Titanium standard, incl. spacer Length 50.0 mm048.471 Titanium bar matrix, Height 3.5 mm Titanium mini, incl. spacer Length 50.0 mm 19
  22. 22. Bar-borne restorations Fabrication of laser- welded bars with titanium components In addition to the gold variant, the bar can also be composed of prefabricated titanium parts using a laser-welding technique. A synOcta® titanium coping, bar (048.646) and the titanium bar variants standard (048.465) and mini (048.466) are available. The standard and mini titanium matrices which fit the titanium bar (from left to right). The bar segments are fitted to the master cast, allowing a minimum gap. Larger gaps are offset by the addition of more titanium.20
  23. 23. Bar-borne restorationsThe segments are welded togetherwith adequate argon gas rinsing.Important: The soldering pointsmust not show any blue discol-oration. This type of discolorationindicates inadequate argon gasventilation and therefore oxygenuptake by the metal. This makesthe weld brittle and thereforeweakens the bar construction. Thelaser device operating instructionsmust be followed. The finished polished titanium bar.Art. No. Article Dimension Material048.646 synOcta® Titanium coping Height 5.6 mm Titanium bar048.465 Titanium bar, egg-shaped Height 3.0 mm Titanium cross-section, standard length 50.0 mm048.466 Titanium bar, egg-shapend Height 2.3 mm Titanium cross-section, mini length 50.0 mm048.470 Titanium bar matrix Height 4.5 mm Titanium standard, length 50.0 mm incl. spacer048.471 Titanium bar matrix, Height 3.5 mm Titanium mini, incl. spacer length 50.0 mm 21
  24. 24. Bar-borne restorations Fabrication of the definitive bar prosthesis with metal reinforcement Once the bar has been tried in, the denture with metal reinforce- ment can be fabricated. The teeth are set up according to modern full denture principles (e.g., Gerber et al.). Once the wax-up denture has been tried in, the teeth are secured in a plaster or silicone index. To enable the index to be reposi- tioned accurately on the duplicate model, grooves are made in the ground labial surface of the master model. The bar is then blocked out for duplicating. In order to do so, the bar is fitted onto the master model. Important: Before the bar sleeve is positioned, the spacer must be fixed to the bar. This ensures vertical translation of the denture. The bar is then coated with a 0.4 mm-thick wax sheet, which acts as a spacer. Labially and lingually, the wax is only extended to the mucosa. Stops of approxi- mately 4 x 3 mm must be cut out to coincide with the height of the premolars and the second molar.22
  25. 25. Bar-borne restorationsWhen the duplicating mould hasbeen removed, the index can befitted to the duplicate model.The plastic teeth are integratedinto the index and matched to theduplicate model.The dimensions and thickness ofthe lingual surfaces of the teeth tobe built up are governed by theprevailing anatomical conditions.The retainers for the sleeve or ridershould also be positioned to pro-vide good mechanical retention.The areas of the bar rider andstrengthener which contact thedenture acrylic must be silanized(e.g., Rocatec, Silicoater) or bepretreated with a primer.Important: The bar sleeve andrider must not be soldered to themetal framework as this wouldprevent them being replaced at alater date. Also, any heattreatment would adversely affectthe elastic properties of thelamellae.The finished metal-reinforcedjointed bar. 23
  26. 26. Bar-borne restorations Modification of a full lower denture in an implant/bar-borne hybrid denture If the implant-borne anchorage of an existing full denture is neces- sary, this can be fitted with a bar construction after implantation and the relevant healing time. In this case, impression-taking is carried out with the existing denture in combination with one- part, orange colour-coded plastic impression caps (048.092V4). Important: The caps are suitable only for impression-taking of implants with a head diameter of 4.8 mm. First, the healing caps are removed from the implants and the impression caps fitted with a snap- on mechanism. The relevant part of the existing denture is hollowed out. Important: It must be possible to fit the denture over the impression caps without making contact. After adjusting the denture, the impression is taken with the integrated caps, using an elastomeric impression material (polyvinylsiloxane or polyether rubber). To protect the implant shoulder, the healing caps are screwed back onto the implants after the impression-taking.24
  27. 27. Bar-borne restorationsThe master cast is fabricated usingspecial hard plaster. One-part,orange, colour-coded synOcta®analogs (048.142) are available.These are placed in the plasticimpression caps situated in thedenture, and the master cast isthen fabricated in the conventionalway using special hard plaster,type 4 (DIN 13911). It isimportant to fix the bite height,as is usual with, for example,a denture relining. The bar matrices with the spacerAfter removing the denture and the (denture resilience) are positionedimpression material from the on the finished bar construction,plaster master cast, the bar and the undercut points andconstruction procedure is decided, outside of the matrices are blockedand the denture is hollowed out out with wax (to ensure that theyaccordingly. can be activated/deactivated). The denture is then adapted to theThe bar is fabricated as described bar construction by polymerisationon pages 11–14 and/or 18–21. of the matrices. The denture is then checked for surplus plastic in the region of the matrices and for function. Important: This step is essential, because only in this way can the optimum function of the integrated bar matrices (incl. ability to activate/deactivate them) be ensured. Unremoved plastic residue may damage the bar construction/implants. Before the bar is fitted, the synOcta® abutments (048.600) are screwed into the implants with a force of 35 Ncm. 25
  28. 28. Bar-borne restorations Relining an implant-borne bar denture Hybrid dentures with resilient After impression-taking, the bar retention units should be examined stays in the denture, and the at intervals of approximately dental technician inserts the one- 3 months to enable harmful part orange synOcta® implant excursions of the denture to be (048.142) into the bar caps. eliminated in their early stages. The master cast is fabricated and If the alveolar ridge resorbs after prepared for relining in the a prolonged wearing time, the conventional way. bar-borne denture sinks. This Before relining, the bar is secured leads to a loss of resilience of the to the master cast with the SCS matrices and so to greater stress occlusal screws, the undercut on the retentive elements/implants. points are blocked out with wax, Relining then becomes necessary. and the corresponding spacer is fixed in the bar matrix. Relining is then carried out in the conven- tional way. After relining, the spacer is removed and the matrices are checked for surplus plastic and for function. Relining is carried out with the bar in position. First, the occlusal screws (048.350V4) are replaced by fixing pins (048.072V4). These fixing pins are made from plastic, have a snap-on mechanism and are colour-coded orange. They are used only to secure the bar on the implants when taking a relining impression with the denture. The fixing pins are intended for single use only. Important: This step is essential, Important: To preserve the because only in this way can the resilience of the denture, the optimum function of the relined, corresponding spacer must be implant-borne bar denture be inserted between the bar and ensured. Interference with the matrix before impression-taking. functioning of the joint mechanism may damage the implant or bar26 construction.
  29. 29. Bar-borne restorationsCase presentation:Illustrations by courtesy ofDr. J. Röckl, private practice inTeningen, Germany 27
  30. 30. Bar-borne restorations References Besimo C. Mericske-Stern R. Wirz J., Jäger K. Implantatauslenkung bei Force distribution on implants Stegverankerungen implantat- unterschiedlicher Verankerung supporting overdentures: the getragener Hybridprothesen abnehmbarer Suprastrukturen effect of distal bar extentions. Quintessenz 42, 2007–2014 Implantologie 3, 213–223 (1993) A 3-D in vivo study (1991) Clin Oral Implants Res. 1997 Apr; Carisch H. Wirz J. 8 (2): 142–51. Zahntechnische Aspekte bei der Hybridprothese im atrophierten PMID: 9758965; UI: 98431129 Herstellung einer implantatgetra- Unterkiefer genen Unterkiefer-Totalprothese Mericske-Stern R. In: Foitzik Ch. (Hrsg): Quintessenz Zahntech 9, Implantate im zahnlosen Das ITI® DENTAL IMPLANT 913–925 (1987) Unterkiefer SYSTEM. Schweiz Monatschr Zahnmed, Schlütersche Verlagsanstalt, Dolder E. 102: 1215 –1224 (1992) Hannover, S. 129 (1994) Stegprothetik Dr. Alfred Hüthig Verlag, Mericske-Stern R., Belser U., Wirz J., Schmidli F., Schaardt S. Heidelberg, 3. verbesserte und Taylor T. D. Werkstoffkundliche Aspekte der erweiterte Auflage (1971) Management of the edentulous Hybridprothesen Patient Quintessenz 45; 1131–1142 Dolder E., Wirz J. ITI Consensus Paper, 138–155 (1994) Die Steggelenkprothese (1997) Quintessenz Verlag, Berlin (1982) Wirz J., Jungo M., Isaak M. Merz B., Mericske-Stern R., Renaissance der Stegprothetik mit Jäger K., Wirz J. Lengsfeld M., Schmitt J. neuen Werkstoffen und In-vitro-Spannungsanalysen Dreidimensionales FE-Modell Technologien an Implantaten in Abhängigkeit eines zahnlosen, mit Implantaten Teil 1: Quintessenz 50, 611–617 von den hybridprothetischen versorgten Unterkiefers (1999) Suprakonstruktionen Biomedizinische Technik 41: Teil 2: Quintessenz 50, 719–739 Z Zahnärztl Implantol 9: 42–49 Ergänzungsband 1, 34–35 (1999) (1993) (1996) Wirz J. Lang N.P., Brägger U., Spiekermann H. Titan - der Werkstoff für die Hämmerle C.H.F., Mombelli A., Die prothetische Behandlung Teil- und Hybridprothetik mit und Lehmann B., Weigel C. Behandlungskonzept 1 ohne Implantate Das ITI® DENTAL IMPLANT In: Rateitschak K.H., Wolf H.F. Wirz J. u. Bischoff H. (Hrsg.): Titan SYSTEM: Behandlungsstrategie (Hrsg): Farbatlanten der Zahn- in der Zahnmedizin S. 312–332, Basisinformation, Institut medizin 10, Implantologie, Quintessenzverlag, Berlin (1997) Straumann AG (1994) Thieme Stuttgart/New York, S. 150 (1994) Tilse M., Dietrich P., Weingart D. Stegretinierte Hybridprothesen auf Bonefit-Implantaten unter Verwendung des Octa-Systems Implantologie 1: 39–49 (1994)28
  31. 31. Retentive anchorInstructions for dentists anddental techniciansTable of contentsRetentive anchors 29■ Introduction 30■ Fabrication of a new full lower denture with metal reinforcement 31 and two gold matrices■ Fabrication of a new full lower denture with metal reinforcement 36 and two titanium matrices■ Modification of an existing full lower denture in an 42 implant-borne retentive anchor denture■ Relining an implant-borne retentive anchor denture 44 29
  32. 32. Retentive anchor Retentive anchors Introduction Description/Function Indications for Purposes of anchors: The retentive anchor is assigned to retentive anchors the movable attachments. Retentive ■ Securing the prosthesis against ■ Extensive gaps which cannot be units that permit rotary movement excursive forces and those which bridged with bars of the denture in one or more would dislodge the saddles directions and/or vertical transla- ■ Insufficient space available (in ■ Distribution of shear forces tional movements are termed such cases, bars often cause the mobile units. anterior section to be extended ■ To transfer the masticatory forces too far lingually thus restricting as axially as possible from the The mobile connector shortens the the space available for the denture to the implant lever arm of the tilting forces tongue and impeding its exerted on the implant. The functioning) implants must always be placed at ■ In cases of severely tapering an angle of 90° to the occlusal anterior arches and/or jaws plane to ensure that they are (Geering et al., 1993) loaded axially. Precisely designed occlusal surfaces – balanced ■ Single retentive anchors allow occlusion with freedom-in-centric for designs which are gentle on (Geering et al., 1993) – and the periodontium (hygienic) optimum design of the denture fitting surface also influence the Contraindications for stability of the denture and the distribution of the masticatory retentive anchors forces (Worthington et al., 1992). ■ Combined tooth-/implant-borne We recommend that a new restorations denture always be fabricated as ■ In conjunction with attachments part of the treatment plan or after exhibiting a different degree of the provision of implants resilience (Mericske-Stern, 1988). ■ If the implants are not vertical to the occlusal plane ■ In cases where the implants have been positioned in the arch in such a way as to prevent a tangential axis of rotation ■ In unfavourable ridge situations30
  33. 33. Retentive anchorFabrication of a full lower denture with a metalreinforcement and two gold matrices“Patient” initialsituationEdentulous lower jaw with twoimplants replacing the canineswith retentive anchors (048.439).Important: To ensure that theretentive anchors function perfectlyover a long period of time, theimplants must be placed asparallel as possible to one anotherand vertical to the occlusal planeto create a tangential axis ofrotation.The retentive anchor has a squareneck to accommodate the driver,and can be changed if necessary.It is inserted into the implant with aforce of 35 Ncm. Measured fromthe upper edge of the implantshoulder, it is 3.4 mm high. Taking an impression of the retentive anchor The impression is taken with an elastomeric impression material (polyvinylsiloxane or polyether rubber) directly over the anchor, without any aids. Important: In view of its low resistance to tearing, a hydrocol- loid is not suitable for this application.Driver (046.069) with “R.A”.marking (“Retentive Anchor”),retentive anchor (048.439), andtransfer pin (048.109) (from left toright). 31
  34. 34. Retentive anchor Producing the model Transfer pins are positioned in the impression and the model is produced in special, type 4 (DIN 13911) hard plaster. The impression of the retentive anchor, provides the square/spherical stud of the transfer pin with sufficient retention in the impression. To ensure stability, the production and integration of a metal reinforcement in the full lower denture is recommended. Sufficient space must be left for securing the matrices. The teeth should be set up using the occlusal concept for full dentures and in accordance with the treatment plan and then embedded in a flask.32
  35. 35. Retentive anchorThe working principleof the gold matrixThe gold matrix (048.410) consistsof a gold alloy (Elitor; composi-tion: Au 68.6%, Pt 2.5%, Pd4.0%, Ag 11.8%, Cu 10.6%,Zn 2.5%).The four lamellae function like aspring. The force required todisengage the attachment can beincreased by pressing the lamellaetogether (with the activator,046.120) or by spreading them(with the deactivator, 046.121).Important: Only the activator/deactivator described should beused. Under no circumstancesshould the lamellae be bent with awax knife or the like. Should thelamellae be bent singly, the forcesno longer act uniformly on theretentive anchor, which may leadto unilateral stress. This may causethe lamellae to fracture or theretentive anchor to wear unevenly.The use of the activator/deactivator activates/deactivatesthe lamellae uniformly, which guar-antees that they retain the denturewith an equal amount of force. 33
  36. 36. Retentive anchor Before polymerising the matrices, the correct fit of the PVC ring on the matrix must be checked. The PVC ring must be flush with the lower edge of the matrix and leave the retention nut free for the acrylic. The ring acts as a spacer in the denture acrylic and gives the lamellae unrestricted freedom of movement. Should the PVC ring be missing or damaged, a new ring can be assembled with the aid of a special tool (046.153). Once the flask has been opened, the deactivated gold matrices are positioned on the transfer pins with their axes aligned (parallel to the path of insertion) and the undercuts are blocked out. Important: Under no circumstances should the gold matrices be subjected to heat treatment (such as soldering additional retainers or soldering the matrix to a metal framework), otherwise the lamellae on the matrix will not34 retain their elasticity.
  37. 37. Retentive anchorSetting up of the metal reinforce-ment and fixing of the matriceswith acrylic. Completed denture. The denture is forwarded to the dentist with the matrices in a deactivated state. They are not activated until the denture is fitted to the patient’s mouth. 35
  38. 38. Retentive anchor Fabrication of a full lower denture with metal reinforcement and two titanium matrices “Patient” initial situation Edentulous lower jaw with two implants replacing the canines with retentive anchors (048.439). Model starting situation (proce- dure identical as described above for “Fabrication of a full lower denture with metal reinforcement and two gold matrices”). The titanium matrix (048.450) consists of a titanium alloy (Ti-6Al-4V), hardness HV5 Vickers 350–385. Individual components: threaded ring-spring-housing with retainer (from left to right).36
  39. 39. Retentive anchorUnlike the gold matrix, the titaniummatrix makes use of a spring witha defined extraction force of 700–1100g. If retention is lost, thespring can be replaced. To replace the spring, the thread on the titanium matrix is un- screwed anticlockwise using a special screwdriver (048.452) and the spring is changed. The threaded ring is then screwed back in place hand-tight. 37
  40. 40. Retentive anchor The titanium matrices can be polymerised into place as follows: Method A Before positioning the matrices on the transfer pins on the model, the original threaded ring is unscrewed and replaced with a plastic threaded ring (048.454V4). The undercuts are blocked out with plaster. The plastic ring is 3/100 mm wider in diameter than the titanium matrix and acts as a spacer for it. This prevents too tight a fit of the titanium threaded ring on the polymerised acrylic. After polymerisation, the threaded ring is replaced by the titanium ring once more.38
  41. 41. Retentive anchorMethod BThe denture is polymerised withspecial acrylic spacers only(048.451V4). First, the undercutsare blocked out with plaster. Oncethe denture is ready, the spacersare removed and the dentist canpolymerise the titanium matricesinto place directly in the patient’smouth. The spacers are also usedto produce the model for the metalreinforcement. 39
  42. 42. Retentive anchor Method C Before being positioned on the edge of the threaded ring, the titanium matrix is coated with a thin film of die spacer. This ensures that the threaded ring can be released later on without excessive force having to be exerted. Important: With all three methods, the titanium matrices (or spacers) must also always be positioned on the transfer pins with their axes aligned (parallel to the path of insertion) and the undercuts blocked out.40
  43. 43. Retentive anchorThe finished denture with titaniummatrices integrated in the metalframework.Important: Once the denture iscomplete, it must be checked toensure no acrylic has penetratedthe matrix. To do this, the threadedring should be removed and theinner configuration with the springshould be cleaned. Removal of titanium matrix from an existing denture To replace an entire titanium matrix, the threaded ring and spring must first be removed. The tip of a special extractor (048.453) is then heated over a Bunsen burner and screwed into the matrix housing. The housing can then be with- drawn from the acrylic denture. 41
  44. 44. Retentive anchor Modification of an existing full lower denture in an implant-borne retentive anchor denture with gold matrices Polymerisation of the gold matrices in the patient’s mouth after implantation and osseointegration: The existing full lower denture prior to modification. The retentive anchors are inserted into the implants with a force of 35 Ncm. The existing denture is then hollowed out in the region of the anchor. The opening created allows the acrylic to flow in. The gold matrices positioned on the anchor must not touch the denture after hollowing. Prior to polymerising the gold matrices (048.410), the correct fit of the PVC ring must be checked. The PVC ring must be flush with the lower edge of the matrix and leave the retention element free for the acrylic. Should the PVC ring be missing or damaged, a new ring can be inserted with the aid of the PVC ring mounting instrument (046.153). The ring acts as a spacer in the denture acrylic and enables the lamellae to function correctly.42
  45. 45. Retentive anchorAfter positioning on the retentiveanchors, a small piece of rubberdam is placed over the matrices.This prevents the acrylic fromflowing into the internal matrixconfiguration.Important: The matrices must bealigned (parallel to the path ofinsertion).The prepared denture is then fixedin the mouth and the acrylic isflowed through the perforation.The modified denture with thepolymerised gold matrices. 43
  46. 46. Retentive anchor Relining of an implant-borne retentive anchor denture Hybrid dentures with retentive After relining, the matrices should anchors should be checked at be checked for acrylic that may approximately three-month inter- have flowed into them and for vals, to eliminate damaging their functionality. It must also be denture movements by appropriate possible to activate/deactivate the measures at an early stage. gold matrices. After polymerisa- tion, the titanium matrix is opened If the alveolar ridge resorbs after with the relevant screwdriver a prolonged wearing time, the (048.452) and the internal denture may sink. This leads to a configuration is cleaned. loss of resilience of the matrices and so to greater stress on the Important: These measures are retentive anchor/implants. Relining vital, because only in this way is then becomes necessary. the optimum function of the relined, implant-borne anchor denture Relining is carried out directly over ensured. If the function of the matrix the retentive anchors. Care should is impeded, this can damage the be taken to ensure that the denture implant/anchor. is sitting correctly (retentive anchor/ matrix connection). The dental technician then positions the transfer pins (048.109) in the matrices (titanium or gold matrix) in the denture and produces the relining model (see also page 32, Producing the model).44
  47. 47. Retentive anchorEdentulous: retentive anchorRetentive anchor with gold matrix Retentive anchor with titanium matrixChoice of implant Solid screw implant Ø 4.1mm, 4.8 mm; shoulder - Ø 4.8 mmAbutments and Instruments Abutments and Instrumentslaboratory parts laboratory partsInsertion of abutmentsRetentive anchor Driver for retentive anchor Retentive anchor Driver for retentive anchor048.439 046.069 048.439 046.069ImpressionTransfer pin Transfer pin048.109 048.109Production ofdenture Activator Titanium matrix ScrewdriverGold matrix 046.120 048.450 048.452048.410 Deactivator Spacer 046.121 048.451V4 Stamp Threaded mounting 046.153 ring 048.454V4Insertion offinal restoration Activator Spring Screwdriver 046.120 048.455V4 048.452 Deactivator 046.121 Stamp Extractor 046.153 048.453 45
  48. 48. Retentive anchor Case presentation: Illustrations by courtesy of Dr. G.S. Solnit D.D.S., M.S., Beverly Hills, CA (USA)46
  49. 49. Retentive anchorRetentive anchorsArt. No. Article Dimension Material048.439 Retentive anchor Height 3.4 mm Titanium046.069 Retentive anchor driver Length 19.0 mm Steel, stainless048.109 Transfer pin for Length 18.0 mm Steel, stainless retentive anchorGold matrix, activatable048.410 Gold matrix for Height 2.3 mm Elitor retentive anchor046.153 PVC ring Length 31.0 mm Steel, stainless/ mounting instrument anodized aluminium046.120 Activator für gold matrix Length 70.0 mm Steel, stainless/plastic046.121 Deactivator for Length 68.0 mm Steel, stainless/plastic gold matrixTitanium matrix with defined extraction force048.450 Titanium matrix for Height 3.1mm Titanium alloy retentive anchor048.451V4 Spacer for Height 3.5 mm Plastic titanium matrix048.452 Screwdriver for Length 60.0 mm Steel, stainless/ titanium matrix Alu, anodised048.453 Extractor for Length 100.0 mm Steel, stainless titanium matrix048.454V4 Threaded mounting ring Height 2.2 mm Plastic for titanium matrix048.455V4 Spring for 048.450 Steel, stainless 47
  50. 50. Retentive anchor References Besimo Ch., Graber G., Mericske-Stern R. Schaffner Th. Clinical Evaluation of Hybridprothetische implantat- Overdenture Restorations getragene Suprastrukturen im Supported by Osseointegrated zahnlosen Unterkiefer Titanium Implants: ZWR, 100. Jahrg., Teil 1, Fall- A Retrospective Study planung, Nr. 1 und 2 (1991) Int J Oral Maxillofac Implants 5: 375–383 (1990) Cendres & Métaux SA, CH-Biel-Bienne Mericske-Stern R. Konstruktionselemente für die Implantate im zahnlosen Prothetik Unterkiefer Produktekatalog, Klasse 4 (1993) Schweiz Monatsschr Zahnmed 10: 1215 –1224 (1992) Geering A. H., Kundert M. Total- und Hybridtechnik Mericske-Stern R. Farbatlanten der Zahnmedizin, Forces on Implants Supporting G. Thieme Verlag, Overdentures: Stuttgart, 2. Auflage (1993) A Preliminary Study of Morphologic and Lang N.P., Brägger U., Hämmerle Cephalometric Considerations C.H.F., Mombelli A., Lehmann B., Int J Oral Maxillofac Implants 8: Weigel C. 254–263 (1993) Das ITI® DENTAL IMPLANT SYSTEM: Behandlungsstrategie Mericske-Stern R., Steinlin-Schaf- Basisinformation, Institut fer T., Marti P., Geering A. H. Straumann AG (1994) Periimplant Mucosal Aspects of ITI Implants supporting Mericske-Stern R., Geering A.H. Overdentures. Die Implantate in der Total- A 5 year longitudinal study prothetik Clinical Oral Implants Research 5: Die Verankerung der Total- 9–18 (1994) prothese im zahnlosen Unter- kiefer durch zwei Implantate mit Worthington P., Brånemark P.-I. Einzelattachments. Advanced Osseointegration Schweiz Monatsschr Zahnmed, Surgery: Applications in the Vol. 98:8 (1988) Maxillofacial Region Quintessence Publishing Co, In, Mericske-Stern R. Illinois, USA (1992) Eine klinische Longitudinalstudie mit Ergebnissen nach vier Jahren Schweiz Monatsschr Zahnmed, Vol. 98:9 (1988)48
  51. 51. MagnetInstructions for dentists anddental techniciansTable of contentsMagnet 49■ Introduction 50■ Fabrication of a full lower denture with two magnets 53■ Modification of an existing full lower denture to an 58 implant-borne magnetic denture■ Relining an implant-borne magnetic denture 60 49
  52. 52. Magnet Titanmagnetics® Introduction Description/Function The functions of magnetic The magnetic anchor is a dynamic N.B.: Special precautions must be anchorage units: anchor. taken when working with magnets. When carrying out MRI ■ Securing the prosthesis against Retentive units which permit rotary (Magnetic Resonance Imaging) tractive excursive forces and movement of the denture in one diagnoses or taking X-rays, the those which would dislodge the or more directions and/or vertical implant magnets and denture must saddles translational movements are be removed. termed dynamic units. ■ Distribution of shear forces The titanium coating of the The dynamic connector shortens ■ To transfer the masticatory forces Titanmagnetics® inserts and the lever arm of the tilting forces axially from the denture to the denture Titanmagnetics®, is up exerted on the implant. The implant to 0.2 mm thick and air-tight, implants must always be placed at must not be sand-blasted under an angle of 90° to the occlusal any circumstances, otherwise plane to ensure that they are the magnetic alloy (Sm2Co17) loaded axially. Precisely designed would be exposed. This destroys occlusal surfaces – balanced the Titanmagnetics®, releasing occlusion with freedom-in-centric corrosion products into the body. (Geering et al., 1993) – and optimum design of the denture Titanmagnetics® must not be fitting surface also influence the soldered or laser-welded. Extreme stability of the denture and the heat causes an irreversible loss distribution of the masticatory of magnetic force and can damage forces (Worthington et al., 1992). the titanium coating. Damaged We recommend that a new denture Titanmagnetics® must be replaced always be fabricated as part of immediately. the treatment plan or after the provision of implants (Mericske- Stern, 1988; Wirz et al., 1993, 1994).50
  53. 53. MagnetMagnetic fieldsIn the current literature, there is noevidence that permanent magneticfields with field strengths in theregion of 200–300 mT (Millitesla)cause local damage in humans.Titanmagnetics® generate apermanent magnetic field equivalentto the Earth’s natural magnetism.The mean field strengths are186 mT.When the denture is in theresting position, the magneticfield is enclosed within itself(Cerny, 1979, 1980).N.B.: Titanmagnetics® are part of atotal concept and must be usedonly with the corresponding STECO®original parts and ITI instruments,as directed by the manufacturer.The Titanmagnetics® System is aregistered trademark of STECO®. Manufacturer: Steco-system-technik GmbH & Co. KG 0 1 9 7 Kollaustrasse 6 D-22529 Hamburg, Germany 51
  54. 54. Magnet Indications for Contraindications for magnets magnets ■ Extensive gaps which cannot be ■ Combined tooth-/implant-borne bridged with bars restorations ■ Insufficient space available (in ■ In conjunction with attachments such cases, bars often cause the exhibiting a different degree of anterior section to be extended freedom too far lingually thus restricting ■ If the implants are not vertical to the space available for the the occlusal plane tongue) ■ In cases of severely tapering anterior arches and/or jaws ■ Periodontium-friendly design with a magnet (hygienic); particularly suitable for elderly and/or disabled patients)52
  55. 55. MagnetFabrication of a full lower denture withtwo Titanmagnetics®“Patient” initialsituationEdentulous lower jaw with twoimplants replacing the canines withTitanmagnetics® inserts (048.511).Important: To ensure that theTitanmagnetics® insert functionperfectly over a long period oftime, the implants must be placedas parallel as possible to oneanother and vertical to the occlusalplane to create a tangential axisof rotation.The Titanmagnetics® insert is fittedwith an external octagon toaccommodate the Titanmagnetics®insert applicator, and can bereplaced as required. It is screwedinto the implant with a force of15–20 Ncm. Measured from theimplant shoulder, it is 3.25 mm highand has a diameter of 4.8 mm. 53
  56. 56. Magnet Titanmagnetics® insert applicator (046.146) and Titanmagnetics® insert (048.511). Denture Titanmagnetics® (048.515), positioning cuff (048.516). Titanmagnetics® impression cap (048.014), Titanmagnetics® model implant (048.121).54
  57. 57. MagnetImpression-taking withthe Titanmagnetics®insertThe impression is taken with anindividually produced plasticimpression tray with an elasto-meric impression material (poly-vinylsiloxane or polyether rubber)over the Titanmagnetics®impression cap positioned onthe Titanmagnetics® insert.Important: Due to its insufficienttensile strength and poor elasticrecoil, hydrocolloid is not suitablefor this application.Producing themaster castThe Titanmagnetics® model implantsare then placed in the impressionposts and the master cast isfabricated using special hard,type 4 (DIN 13911) plaster.The analogues and impression postsare retained by magnetic force.Tip: To ensure stability, the produc-tion and integration of a metalreinforcement in the full lowerdenture is recommended. Sufficientspace must be left for positioningthe denture Titanmagnetics®. 55
  58. 58. Magnet The finished plaster model. Before fabricating the wax model, the positioning cuffs are placed as a spacer between the Titan- magnetics® insert and the denture Titanmagnetics®. The thin silicon lip is removed with fine scissors/blade. With the aid of the positioning cuff, a defined area is left free around the Titanmagnetics®, facilitating the easy, stress-free insertion and removal of the denture. The teeth should be set up using the occlusal concept for full dentures and in accordance with the treatment plan.56
  59. 59. MagnetBasal view ofder Wachsauf-Basalansicht wax model.stellung.After the wax trial, the denture isfinished using, for example, theflask technique.Important: After polymerisation,any plastic residue must be carefullyremoved from the shiny undersideof the denture Titanmagnetics®.The magnets must not be sand-blasted.Denture Titanmagnetics® in situ.The space created by the use ofthe positioning cuff (resiliencecompensation) is clearly visible. 57
  60. 60. Magnet Modification of an existing full lower denture on an implant-borne magnetic denture “Patient” initial situation Edentulous lower jaw with two implants replacing the canines with Titanmagnetics® inserts (048.511), inserted with a force of 15–20 Ncm. The positioning cuff (048.516) is placed on the Titanmagnetics® insert and the denture Titanmagnetics® is placed over that. The positioning cuff acts as a spacer and keeps the two Titanmagnetics® approx. 0.3 mm apart. This ensures resilience of the denture on the gingiva. During intra-oral poly- merisation, the flexible lip of the positioning cuff prevents liquid plastic from coming into contact with the gingiva and implant. N.B.: Titanmagnetics® must not be ground.58