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#4:2Volume 4, Issue 2. 2001
TiOblast™ – State of the Art ......................3Maintaining the Bone ..............................6Surgical Innovations ................................9
Optimizing Esthetics ..............................13Solving Difficult Cases ............................14Documentation Summaries ......................18
TiOblast™ –The Surface of Choice
PublisherThe Astra Tech Insight is published and distrib-uted worldwide by Astra Tech AB, P.O. Box 14,SE-431 21 Mölndal, Sweden. Astra Tech is acompany in the AstraZeneca Group.
Editor-in-chiefMia Jensen, DDSClinical Information Manager, DentalAstra Tech AB
Associate editorAnders Holmén, DDSMedical Director, DentalAstra Tech AB
Contact usEditors can be reached at the above address and at
Please mail your questions, opinions andthoughts on the Astra Tech Insight.
SubscriptionContact your local office or the Astra Tech mainoffice directly on the above mentioned address.
CopyrightAll rights reserved, including that of translationinto other languages. No part of this publica-tion may be reproduced or transmitted in anyform or by any means, electronic or mechan-ical, including photocopying, recording or anyinformation storage or retrieval system, withoutpermission in writing from Astra Tech AB.
Editorial contentAlthough great care has been taken in compil-ing and checking the information given in thispublication to ensure it is accurate, the publishershall not be held responsible for the continuedcurrency of the information or for any errors,omissions or inaccuracies in this publication.
The opinions expressed in this publication arenot necessary those of the publisher or editor-in-chief.
Submitted material will be stored electronicallyfor the possibility of publication on the Internet,reprints and in other manners.
Editorial content developed in conjunction withAdis International Limited, Chowley Oak Lane,Tattenhall, Chester, CH3 9GA, UK.
Layout Layout developed with assistance of theadvertising agency Explicit & Partners, Göte-borg, Sweden.
PrintingPrinted in Sweden by Göteborgstryckeriet.
ContentsTiOblast™ – State of the Art..........................3The TiOblast™ surface is backed up by comprehensive documentation.
Maintaining the Bone..................................6Results of a 5-year study on single tooth replacements with Astra Tech Fixture ST.
Surgical Innovations ..................................9Two new techniques in mandibular pre-prosthetic reconstruction.
Optimizing Esthetics – Angled Abutment System ..........................13The new Angled Abutment offers flexibility in many demanding situations.
An Improved Prosthetic Option –Solving Difficult Cases ..............................14Clinical experience of avoiding buccal screw holes with the Angled Abutment System.
New Components – Same procedures ........16The laboratory procedures remain the same with the new Angled Abutment.
Keep Updated with Scientific Literature ......18The new publication Astra Tech Documentation Summaries will increase your knowledge.
Astra Tech Calendar..................................19
Cover: The TiOblast™ surface in high magnification.
INSIGHT #4:2:2001 3
Anders Holmén, DDS Medical Director, Dental Astra Tech AB
D O C U M E N TAT I O N
Astra Tech currently provides theonly enhanced implant surface withcomplete documentation – TiOblast™.Other implant manufacturers providerough surfaces on their implants, andwhile some have pre-clinical scientific
data to back up their claims, there islimited clinical data available.
Surface design and documentationThe story behind TiOblast™ tells of adocumentation and development
process as good as it gets. In the early1990’s Astra Tech hypothesized thatan implant surface with a “rougher”surface would provide a better boneto implant interface. This was basedon clinical results with an early
TiOblast™
State of the Art
SummaryTiOblast™ is the only enhanced implantsurface backed by comprehensive docu-mentation and long-term follow-up studies.The delvelopment and documentationprocesses include:• Theoretical modeling• Pre-clinical in vivo and in vitro docu-
mentation• Human histology• Clinical documentation.
It is concluded that the TiOblast™ surfaceprovides outstanding and predictableresults with superb survival/success fig-ures for implants with marginal bonelevels.
Rough implant surfaces have during the last years been acclaimed tohave certain benefits when compared to machined surfaces. TiOblast™ isthe implant surface of choice for clinicians concerned with using implantcomponents and methods presented together with evidence based claims.
4 INSIGHT #4:2:2001
version of the Astra Tech DentalImplant that provided greater mech-anical interlock in the bone and astable marginal bone level. Othersystem’s published data from animalstudies also reported better quantit-ative and qualitative bone responseswhen a rough implant surface wasused1, 2. Even if these papers did notdefine the micro-topography of thesurfaces used, there was a strongindication that rougher implant sur-faces could provide better resultsthan those of the prefered machinedor turned surfaces.
The most common way to makethe implant surface rougher was tocoat it through a plasma sprayingtechnique. This coating could be either titanium plasma spray (TPS), orhydoxyapatite coating (HA-coating).However, these methods had somedrawbacks including the coatingcoming loose from the implant sur-face and peri-implant infections.Moreover, their design was not basedon well defined biological or bio-mechanical principles, and the pro-duction process did not give adefined and well-controlled result.
The TiOblast™ surface was de-signed according to the idea that themicro-topography of the implant
surface should meet defined biologicalcriteria. It should be possible to pro-duce the surface in a well definedway and the chemistry of the implantsurface should not be jeopardizedthrough any coating procedure.
In his thesis, Stig Hansson pre-sented a theoretical model of theTiOblast™ surface based on biologicaland biomechanical principles3.
Through a blasting method, where theblasting media is TiO2 -particles withdefined properties, it was possible tocreate an implant surface with thedesired micro-topography withoutcontamination of the surface. Whenthis surface was tested in experi-mental animal and in vitro studies, itprovided data that supported theproposed model3–6. Both qualitative
12 WEEKS
Gotfredsen et al 1992. [8]
Removal Torque (Ncm)
TiOblast
Machined
4 MONTHS
Bone to Implant Contact (%)
Ericsson et al 1994. [9]
3 WEEKS
Bone to Implant Contact (%)
Gotfredsen et al 1995. [10]
3 WEEKS
Removal Torque (Ncm)
Gotfredsen et al 1995. [10]
TiOblast
Machined
TiOblast
Machined
TiOblast
Machined
TiOblast™ claims
• TiOblast™ is the only rough implant surface modeled from both bio-logical and biomechanical principles3–6.
• TiOblast™ has been documented and compared to machined surfaceswith the results being published in peer-reviewed scientific journals. Theresults show qualitative and quantitative advantages for the TiOblast™
surface on the bone to implant interface in dog mandible8, 9 and rabbittibia models10, 11.
• TiOblast™ has been documented with human histology showing signifi-cant increased bone to implant contact compared to machined sur-faces7.
• TiOblast™ is documented in several clinical studies with up to 5 or moreyears follow-up12–17.
INSIGHT #4:2:2001 5
Wennerberg et al 1995. [18]
12 WEEKS
Bone to Implant Contact (%)
12 WEEKS
Bone to Implant Contact (%)
Machined
TiOblast
Wennerberg et al 1996. [11]
and quantitative bone measurementsgave significantly better results forTiOblast™, when compared to amachined surface. Human histologyis also available presenting the samepositive results for TiOblast™ whencompared with a machined surface7.
From documented clinical resultsusing the TiOblast™ surface, it can beconcluded that it gives outstandingpredictable results with survival/success figures in the range of98–100% for upper and lower jawswith marginal bone levels in a steadystate before loading.
2. Al-Sayyed A, Deporter DA, Pilliar RM, et al.Predictable crestal bone remodelling aroundtwo porous-coated titanium alloy dentalimplants designs. Clin Oral Implant Res 1994;5: 131-141.
3. Hansson S, Norton M. The relation betweensurface roughness and interfacial shear strengthfor bone anchored implants: A biomechanicalapproach...Towards optimized dental implant...(thesis, Hansson S) 1997
4. Hansson S, Norton M. The implant neck:smooth or provided with retention elementsA biomechanical approach. Clin Oral Impl Res 1999;10: 394-405
5. Hansson S, Norton M. The relation betweensurface roughness and interfacial shear strengthfor bone anchored implants: A mathematicalmodel, J Biomech 1999;(8): 829-836
6. Hansson S, Surface roughness parameters aspredictors of anchorage strength in bone: acritical analysis. J. Biomech 2000;33: 1297-1303
7. Ivanoff CJ, Widmark G, Hallgren C,Sennerby L, Wennerberg A. Histologic evalu-ation of the bone integration of TiO2 blastedand turned titanium microimplants in humans.Clin Oral Impl Res 2001 Apr;12(2): 128-134
8. Gotfredsen K, Nimb L, Hjörting-Hansen E,Jensen JS, Holmén A. Histomorphometric andremoval torque analysis for TiO2-blasted titan-ium implants, Clin Oral Impl Res 1992;3: 77-84
9. Ericsson I, Johansson CB, Bystedt H, NortonMR. A histomorphometric evaluation of bone-to-implant contact on machined-prepared androughened titanium dental implants, Clin OralImpl Res 1994;5: 202-206
10. Gotfredsen K, Wennerberg A, Johansson C,Skovgaard LT, Hjörting-Hansen E. Anchorageof TiO2-blasted, HA-coated, and machined
implants: an experimental study with rabbits, JBiomed Mater Res 1995 Oct;29 (10): 1223-31
11. Wennerberg A, Albrektsson T, Johansson C,Andersson B. Experimental study of turnedand grit-blasted screw-shaped implants withspecial emphasis on effects of blasting materialand surface topography, Biomaterials 1996Jan;17 (1): 15-22
12. Palmer RM and Smith PJ. A 5-year pro-spective study of Astra single tooth implant.Clin Oral Impl Res 2000;11: 179-182
13. Karlsson U, Gotfredsen K, Olsson C. A 2-year report on maxillary and mandibular fixedpartial dentures supported by Astra Tech DentalImplants. Clin Oral Impl Res 1998;9: 235-242
14. Karlsson U, Gotfredsen K, Olsson C.Single-tooth replacement by osseointegratedAstra Tech dental implants: A 2-year report.Int J Prosthodont 1997;10: 318-324
15. Kemppainen P, Eskola S, Ylipaavalniemi P.A comperative prospective clinical study oftwo single-tooth implants: A preliminaryreport of 102 implants. J Prosthet Dental1997;77: 382-387
16. Gotfredsen K, Karlsson U. A prospective 5-year study of fixed partial prosthesis supported by implants with machined andTiO2-blasted surface. J Prosth. 2001;10: 2-7
17. Åstrand P, Engquist B, Dahlgren S, EnquistE, Feldman H and Gröndahl K. Astra Tech andBrånemark system implants: a prospective 5-year comparative study. Results after oneyear. Clin Impl Dent and Rel Res 1999;1: 17-25
18. Wennerberg A, Albrektsson T, AnderssonB, Krol JJ. A histomorphometric and removaltorque study of screw-shaped titanium implantswith three different surface topographies, ClinOral Impl Res 1995 Mar;6 (1): 24-30
Human Histology (%)
TiOblast
Machined
TiOblast
Machined
Ivanoff CJ. [7]
BIC: Bone to Implant contact on a light microscopic level
BAT: Bone Area in Threads, representing the percentage ofbone tissue within the threads
TiOblastMachined
References
1. van Steenberghe, D et.al. A prospective split-mouth comparative study of two screw-shaped self-tapping pure titanium implantsystems, Clin Oral Impl Res 2000: 11: 202-209
For many patients, the loss of a singletooth can create functional, estheticand psychological problems. It is notunusual that young patients with anotherwise intact dentition need asingle tooth restoration because oftrauma and/or aplasia. The introduc-tion of osseointegrated titaniumimplants, as anchors for single toothrestorations, offers the possibility oftooth preservation. This treatmentpreserves the anatomy of the alveolarridge better than conventional pros-
thetic treatment and provides a betteresthetic and functional result.
Six centers participated in this openprospective study in Scandinavia. Atotal of 47 patients (26 males and 21females) were treated with Astra TechFixture ST. The Fixture ST is a screwshaped and self-tapping fixturemade of commercially pure titanium,with a coronally tapered part charac-terised by microthreads and a surfacewhich has been roughened by blast-ing with titanium particles, TiOblast™.
6 INSIGHT #4:2:2001
Ulf Karlsson, DDSDepartment of Prosthodontics and Periodontology, Norrköping,Sweden
Maintaining the Bone Preliminary Results of a 5-Year Prospective Study
For many patients, the loss of a single tooth can create functional, estheticand psychological problems. It is not unusual that young patients with anotherwise intact dentition need a single tooth restoration because of traumaand/or aplasia.
C L I N I C A L R E S E A R C H
SummaryTo document the long-term outcomes ofsingle-tooth replacement, 47 Fixture STimplants were placed according tostandard protocols. Implant survival ratewas 100%, mean marginal bone lossvery low and the soft tissue health wasmaintained.
TiOblast™ microthreaded implants fromAstra Tech can be used for single-toothrestorations to:• achieve successful integration with high
predictability• preserve the surrounding bone level• maintain esthetics and soft tissue
health.
Preliminary resultsImplants were placed according toguidelines in a two-stage procedureand allowed to heal for 3 months inthe mandible and 6 months in themaxilla before being uncovered.Radiographs were taken at cementa-tion of the prosthetic restoration and,following cementation, at yearlyintervals for a period of 5 years.
A total of 47 implants were placed,37 in the maxilla and 10 in the mand-ible. Forty-three patients receivedporcelain-fused-to-metal crowns and4 received all ceramic crowns asprosthetic restorations. Three patientshad to have dehiscences coveredwith Gore-Tex® membrane (W.L.Gore, USA). No implants were lostand hence there was an implant sur-vival rate of 100% over 5 years and
the marginal bone level was main-tained with very limited bone loss.This is consistent with other studieson Astra Tech Fixture ST.
Most bone loss took place duringthe healing period and remainedstable after loading. 80 % of the pa-tients experienced less than 1.0 mmbone loss over a 5-year period.
Signs of peri-implant inflammationwere noted in 3 patients but easilyresolved with professional cleaningand hygiene instruction. Minorretraction of the buccal soft tissuewas seen in 4 patients, but did notexceed 1 mm in any case.
Few complicationsIn this study, 6 of 47 patients (13%)were lost to follow-up, which is com-parable to other published studies1.
Bone level was maintained with verylimited bone loss which has beenshown in other studies on Astra TechFixture ST2, 3.
Abutment loosening may some-times occur in single crown restora-tions. In a study using an implantsystem with a flat top hex design, ahigh incidence of screw looseningwas reported, especially during thefirst year of loading1. During the pre-sent study, only 4 abutments neededretightening, confirming the resultsof other studies showing the internalconical fixture-to-abutment connec-tion to be very stable4, 5.
Some authors have suggested thatroughened fixture surfaces may in-crease the risk of soft tissue inflam-mation due to plaque accumulation.In this study, superficial inflamma-
INSIGHT #4:2:2001 7
1. Single-tooth restoration maxillaryleft central incisor. Man 36 years old.
2. Single-tooth restoration in the position of maxillary right lateral
incisor. Female 24 years old.
4. Radiographs taken at 3-year follow-up.
3. Radiograph taken at baseline.
8 INSIGHT #4:2:2001
Enhance Your Knowledge!Welcome to the Astra Tech Dental Implant Education Program 2001, which will cover all aspects of implant rehabilitation. The Program is customized for all categories involvedin the treatment procedure and provided at different levels, from basic to advanced implant rehabilitation.
SEPTEMBER 24-25 Clinical Training Course – Surgical Procedures. Stockholm, SwedenFor the clinician involved in implant surgery and with some knowledgeof implant treatment.
OCTOBER 3-5 Clinical Training Course – Advanced Implant Surgery. Göteborg, SwedenFor the experienced clinician involved in implant surgery
OCTOBER 10-12 Dental Assistant Course – Implant Rehabilitation. Göteborg, SwedenFor the dental assistant involved in surgical as well as prosthetic procedures in implant rehabilitation.
NOVEMBER 9-10 Dental Technician Course – Laboratory Procedures. Oslo, NorwayFor the dental technician with some experience from implant laboratory procedures and the clinician with an interest in laboratory procedures.
DECEMBER 6-7 Clinical Training Course – Implant Treatment in Difficult Cases.Göteborg, SwedenFor the clinician involved in implant surgery with experience fromimplant rehabilitation.
For further information, please contact your local Astra Tech dental representative or Ingrid Johnsson, Astra Tech AB, Mölndal, Sweden. E-mail: [email protected]
tion of the peri-implant mucosa wasseen in only 3 patients, a findingwhich is consistent with other docu-mentation6. This shows that theTiOblast surface of Astra Techimplants is not associated with anincreased incidence of peri-implantinflammation compared to implantswith machined surfaces.
ConclusionThe preliminary results from this pro-spective multicenter study show thatTiOblast microthreaded Astra TechDental Implants can be used in singletooth restorations to:• achieve successful integration with
high predictability• preserve the surrounding bone
level• maintain esthetics and soft tissue
health.
References
1. Henry PJ, Laney WR, Jemt,T et al. Osseo-integrated implants for single tooth replace-ment: a prospective 5-year multicenter study.Int J Oral Maxillofac Implants, 1996; 11: 450-455
2. Palmer RM, Palmer PJ, Smith BJ. A 5-yearprospective study of Astra single toothimplants. Clin Oral Impl Res, 2000; 11: 179-182.
3. Norton MR. The Astra Tech single-toothimplant system: a report on 27 consecutivelyplaced and restored implants. Int J Perio-dontics Restorative Dent, 1997; 17: 574-583
4. Åstrand P et al. Astra Tech and BrånemarkSystem implants: A prospective 5-year compa-rative study. Results after one year. Clin ImplDent Rel Res, 1999; 1:1: 17-25
5. van Steenberghe D, Callens A, Geers L, et al.A prospective split-mouth comparative studyof two screw-shaped self-tapping pure titani-um implant systems. Clin Oral Impl Res, 2000;11: 202-209
6. Puchades-Roman, L et al. A Clinical, Radiographic, and Microbiologic Comparisonof Astra Tech and Brånemark Single ToothImplants, Clin Impl Dent Rel Res 2000, 2: 78–84
INSIGHT #4:2:2001 9
Distraction techniqueVertical distraction osteogenesis1, 2
was chosen as the technique for boneaugmentation in this case involvingtotal edentulism in the mandible. A 78-year-old healthy woman hadpreviously experienced an attemptedinstallation of dental implants in thelower jaw. This was discontinueddue to the limited amount of boneavailable in the horizontal aspect(Fig.1).
Ridge expansionUnder general anesthesia, a 1.5 mmtitanium miniplate distractor appar-atus (Martin Medizintechnik GmbH,Germany) was applied horizontallyto the mandible (Figs. 2 and 3). Ahorizontal through-and-throughosteotomy of the mandible betweenthe mental foramina was carried outallowing a 70-mm-long segment tobe mobilized (Fig. 4). The expansionscrew of the device penetrated the
C L I N I C A L R E P O R T
Surgical Innovations Two New Techniques in Mandibular Preprosthetic Reconstruction
Andreas Thor, DDSDepartment of Oral and Maxillofacial Surgery, Stockholm Söder Hospital.
Department of Surgical Sciences,Oral and Maxillofacial Surgery,Uppsala University Hospital.
Sweden
SummaryIn patients in whom there is insufficientmandibular bone for dental implants,restoration of the jaw must be precededby augmentation of the recipient bone. In this article, two cases are reported inwhich different surgical techniques – vertical distraction osteogenesis and the
‘tent-pole procedure’ of bone grafting areused to increase bone volume prior toprosthetic installation. Both these tech-niques were found to be effective in pro-viding a platform for subsequent implanta-tion of stable dental fixtures.
This article illustrates two patients and two different surgical techniquesused in the mandible where the bone volume of the alveolar crest wasinsufficient for installation of dental implants.
10 INSIGHT #4:2:2001
mucosa in the patient’s vestibulum,and after a period of six days thisscrew was used to activate the dis-traction apparatus.
The patient could extend the bonegap by 1 mm per day at home. Thedistraction gap was widened for 12days and then the distractor was leftin place for 3 months to consolidatethe gap (Fig. 5).
Implant installation and restorationAfter this period, the clinical situ-ation was found to be stable, but thegap showed no radiographic signs of mineralization (Fig. 6). Therefore,with the patient’s age in mind, thehealing time was prolonged by 2months. Under conscious sedationand local anesthesia, the distractiondevice was removed and fixturesinstalled. Six Astra Tech TiOblast™
fixtures (Astra Tech Implants,Mölndal, Sweden) of 15 mm lengthand 3.5 mm gauge were installed(Fig. 7). Mineralized bone was clinic-ally and histologically evident in thegap of the osteodistraction.
After three months the implantswere uncovered and healing abut-ments were connected. The implantswere found to be stable in clinicallyhealthy bone and the sagittal relation-ship to the upper jaw was favorable.
1. Thin alveolar crest of the mandible. 3. Distraction apparatus in place.2. Horizontal osteotomy of the mandible.
4. Clinical appearence of mounteddistractor.
5. Distraction complete.
6. Radiological appearance after 3 months.
7. Fixtures in place. 8. Clinical result of the final restoration.
Distraction Technique Deficiency in the bucco/lingual aspect of the anterior mandible
INSIGHT #4:2:2001 11
A fixed bridge was then fabricated,thus completing the treatment (Fig. 8).
Bone grafting with platelet gelIn some cases, resorption of the mand-ible is extremely progressive. Thissecond case illustrates a situation inwhich the patient presented with amaximum residual bone height of6 mm (Figs. 9, 10, 11). The patient, a71-year-old woman, had severe prob-lems with a prosthesis that could not be worn satisfactorily. The instru-mentation for osteodistraction of amandible with such a small amountof vertical residual bone was notcommercially available at this time soan alternative technique was chosen.
Extra-oral incisionUnder general anesthesia, the anteriormandible was exposed through anextraoral submental incision. The lin-gual insertions of the tongue muscleswere kept in place during dissectiontogether with as much of the lingualperiosteum as possible. The areasaround the mental nerves wereproperly exposed and protected.
Six Astra Tech Microthread™
fixtures (15 mm length and 3.5 mmgauge) were placed between themental foramina in approximately 6 mm of bone (Fig. 12). Particulatedbone from the inner cortical table ofthe patient’s iliac crest was mixedwith an autologous platelet gel andplaced around and between the
fixtures (Fig. 13). No communicationwith the oral cavity through the oralmucosa could be seen. The flap, withthe periosteal envelope created, wasthen folded back to the original sub-mental position and sutured back inplace, covering the mandibular bone,fixtures and bone graft.
Prosthetic constructionAfter 2 months and 3 weeks, abut-ments were placed using a standardintraoral technique. The supportinggrafted bone was well vascularizedand minimally resorbed. The pros-thetic part of the treatment couldthen be initiated and finished. Due to a pronounced Class II relationship,a bar (Fig. 14) was constructed and
9. 3-D reconstruction from CT-scan ofmandible preoperatively.
11. Panorex showing preoperative status.
10. Frontal tomography indicating asmall amount of residual bone.
12. Fixtures installed. 13. Bone graft and platelet gel coveringfixtures.
14. 6-months radiological follow-up.
Bone grafting with platelet gelDeficiency in the vertical dimension of the anterior mandible
12 INSIGHT #4:2:2001
attached to the fixtures so that thepatient could wear a removable den-ture. In this way, the risk of overload-ing the fixtures due to unfavorablebite forces was eliminated.
DiscussionDistraction osteogenesis, as used incase one, is a technique that wasdeveloped for clinical orthopedic useby Ilizarov.3 Primarily developed forlengthening of extremities, it wasfurther developed for oral and maxil-lofacial use during the last threedecades.4–6
Case two describes a technique“the tent-pole procedure” developedby Dr Robert Marx at the Universityof Miami (personal communication,1998). Initiated by Tayapongsak et
al.8, Marx has further developed and described the use of autologousplatelet gel for mandibular recon-structions.9 The basic philosophybehind this concept is that growthfactor-containing α-granulae in plate-lets enhance bone graft maturation.Further, gel (with platelets) addsmolding ability to the particulatedgraft. With the fixtures as space-holding poles and periosteum as atent, as in this case, the bone is keptin place and held stationary for theimportant initial two weeks whenthe graft is revascularized. The pat-ient can start using the remodeledold prosthesis after these two weeksof initial healing, but care must betaken that the prosthesis does notcause pressure to the end sides of the
grafts. This was seen to some extentin the second case and caused somemarginal bone loss on the posteriorfixture bilaterally. Despite the shortfollow-up time of 13 months, theresult has been stable and promising.
In conclusion, new concepts andnovel ideas in preprosthetic mand-ibular reconstruction, developed byinnovative surgeons, allow patients asecond chance of having a fixedprosthesis on dental implants andwill improve their quality of dailylife. The above described techniquescan be useful in problematic caseswhere vertical augmentation of thedeficient mandibular alveolar crestmust be performed.
References
1. Block MS. Chang A. Crawford C.Mandibular alveolar ridge augmentation in thedog using distraction osteogenesis. J. OralMaxillofac. Surg. 1996; 54: 309-314
2. Hidding J. Lazar F. Zoller JE. Initial outcomeof vertical distraction osteogenesis of theatrophic alveolar ridge. Mund KieferGesichtschir 1999; 3: 79-83
3. Ilizarov GA. Basic principles of transosseouscompression and distraction osteosynthesis.Ortop. Travmatol. Protez. 1971; 32: 7-15
4. Snyder CC. et al. Mandibular lengtheningby gradual distraction: Preliminary report.Plast. Reconstr. Surg. 1973; 51: 506
5. McCarthy JG. et al. Introduction of an intra-oral bone-lengthening device. Plast. Reconstr.Surg. 1995; 96, 978-981
6. Cope JB. Samchukov ML. Cherkashin AM.Mandibular distraction osteogenesis: a historicperspective and future directions. Am. J.Orthod. Dentofacial. Orthop. 1999; 115: 448-460
7. Raghoebar GM. Heydenrijk A. Vissink A.
Vertical distraction of the severely resorbedmandible. The Groningen Distraction Device.Int. J. Oral Maxillofac. Surg. 2000; 29: 416-420
8. Tayapongsak P. et al. Autologous fibrinadhesive in mandibular reconstruction withparticulate cancellous bone and marrow. J.Oral Maxillofac. Surg. 1994; 52: 161-166
9. Marx RE. et al Platelet-rich plasma. Growthfactor enhancement for bone grafts. Oral Surg.Oral Med. Oral Pathol. Oral Radiol. Endod.1998; 85: 638-646
The new Angled Abutment systemprovides angled abutments that fit all fixtures in the Astra Tech DentalImplant System.
The abutments are connected tothe fixtures with a tight and stablerelation created by the Conical SealDesign™.
Clinical handling procedures aresimplified and improved with thenew product.
Simplicity One solid componentEsthetics No buccal vertical abut-
ment height-no kneeReliability Secure installation
The Angled Abutment consists of anabutment and an abutment screwand is manufactured from commer-cially pure titanium, grade 4. It has anangle of 20° from the axial directionof the fixture and is seated and re-tained to the fixture via the AngledAbutment Screw. It has a low shoulderdesign for high esthetics and can berotated 360° and secured in the de-sired position.
PropertiesAbutments can easily be placed inparallel positions. An indexing featureis provided on the Angled Abutmentto facilitate a correct position of theabutment or abutment replica duringthe prosthetic procedures. Four dif-ferent configurations of the AngledAbutment are available: 3.5, 4.0,4.5/5.0 and 4.5/5.0 High, which canbe combined with any of the fixturesin the Astra Tech Dental ImplantSystem. It is connected to the fixture
and tightened with the Angled Abut-ment Screw using a Hex Screwdriveror a Hex CA driver, the recommendedtorque is 25 Ncm.
The Angled Abutment Systemalso includes prosthetic and laborat-ory components, designed for preci-sion and ease-of-use during everyclinical and laboratory step, fromimpression on abutment level to thefinal installation of the preferablerestoration.
INSIGHT #4:2:2001 13
Optimizing Esthetics
Angled Abutment System
Ann Wretlind, CDTTherapy Manager, Laboratory, DentalAstra Tech AB
The new Angled Abutment provides esthetic solutions for screw retained prosthesis in situations where fixtures are placed in buccallyinclined positions.
P R O D U C T P R E S E N TAT I O N A N G L E D A B U T M E N T
Angled Abutment and Angled Abutment Screw
Heling Cap,Angled
Angled Abutment
Pick-up
Semi-BurnoutCylinder, Angled
TitaniumCylinder,Angled
Angled Abutment
Replica
Esthetic problems tend to appear incases with buccally inclined implantsusing screw-retained restorations.The new and improved Angled Abut-ment makes it possible to achieveoptimal esthetics in these cases.
PlanningPlacing angled abutments in an optimal position directly in themouth requires careful planning.This is particularly the case in fullarch restorations in need of multipleangled abutments. The fact that thesecomponents can be rotated in the
implant without any lock mechanismprovides unlimited positioning pos-sibilities. In addition, the angulationbetween abutments and inclinationof any adjacent teeth have to betaken into consideration. Therefore,we strongly recommend that the firstimpression is taken at fixture level.This recommendation also applies toregistration of the horizontal andvertical relations and the try-in ofteeth in wax.
Placing Angled Abutments The try-in work from the laboratory
14 INSIGHT #4:2:2001
C L I N I C A L R E P O R T A N G L E D A B U T M E N T
Erland Eggum, DDS,Specialist in Prosthodontics, Sola,Norway
An Improved Prosthetic Option
Solving Difficult Cases
Even with adequate planning and routine use of surgical stents, fixturesmight be placed in buccaly inclined positions. The new Angled Abutmentfrom Astra Tech makes it possible for the prosthodontist to solve thesecases satisfactory even with screw retained prosthesis.
SummaryThe new Angled Abutments for the AstraTech System are adaptable and easy touse. They can be rotated 360° and easilycombined with existing Uni Abutments inthe Astra Tech System. Thus the Angled
Abutments allow the optimal positioningof implants in most difficult cases and stillachieving optimal esthetics and function.
INSIGHT #4:2:2001 15
should make the suggested place-ment and length of the abutmentsapparent for the dentist, guiding himin his effort of optimal positioning inthe patient’s mouth. After the correctplacement of the angled abutments,the dentist can choose whether tomake a control cast from an alginateimpression or to go directly for thefinal impression.
The dentist should make sure the abutments are tightened with therecommended torque (25 Ncm).
Final impressionThe angled abutment pick-ups andthe guide pins are used on the seatedangled abutments, ensuring theindexing feature fits correctly. Animpression is taken in a custom madetray with for instance polyetherimpression material. Between patientsessions, angled healing caps shouldbe placed on the abutments to avoidthe ingrowth of soft tissue. Whereangled abutments are inclined pal-
atally this is of particular importance,due to the increased amount of dis-placed gingival tissue.
If the patient is wearing a fulldenture, it will have to be adjusted tothe width and height of the healingcap and a soft lining will give thedenture sufficient retention duringthe treatment period.
Try-in of the metal frameworkBy using a temporary bridge for aperiod of time, possible esthetic,hygienic, functional and phoneticproblems can be detected. The try-inof the metal framework should bedone carefully until it is perfectlyseated. Having studied the situationon the working model, the dentistwill know exactly when the restora-tion is correctly seated.
Final restorationThe final restoration should be performed using regular laboratorytechniques.
The bridge work is secured withbridge screws at the recommendedtorque 15 Ncm.
ConclusionThe Angled Abutment from AstraTech is a new important componentfor solving difficult cases. In order toavoid buccal screw holes in buccallyinclined implants the Angled Abut-ment is an outstanding prostheticoption.
1. Bridgework only with the UniAbutment.
3. Angled Abutments placed in themouth.
5. Try-in of the metal framework withthe Semi-Burnout Cylinder, Angled as abase.
6. Occlucal view of the supraconstruc-tion using the new Angled Abutmentafter replacing the Uni Abutment shownin picture 1.
2. The new Angled Abutment in com-bination with the Uni Abutment.
4. Impression taking on the AngledAbutment using the Angled AbutmentPick-up.
References
1. Balshi TJ, Ekfeldt A, Stenberg T, Vrielinck L.Three-year evaluation of Brånemark ImplantsConnected to Angulated Abutments. Int J OralMaxillofac Implants 1997;12 :52-58.
2. van Steenberghe D, De Mars G, Quirynen M,Jacobs R, Naert I. A prospective split-mouthcomparative study of two screw-shaped self-tapping pure titanium implant systems. ClinOral Impl Res 2000;11 :202-209.
16 INSIGHT #4:2:2001
Study modelWhen the clinician has taken animpression at the fixture level for thestudy cast, the laboratory can fabricatea study model. In order to check theposition of the fixture, the guide pinfor fixture impression can be used as a direction indicator in the replica.A try-in of prefabricated teeth and awax-up can be done at the fixturelevel to evaluate the clinical situation.In this way it is easier for the clinici-an to make the correct decision onwhat abutments to use.
The impression and working modelA custom made tray is fabricated inthe laboratory and sent to the clinicfor an abutment level impression.When the laboratory receives thefinal impression it is important tomake sure that the inside of theangled abutment and uni abutmentpick-ups are free from impressionmaterial. It is also important to makesure that the pick-ups are secured in a stable position in the tray andimpression material. Place the angled
L A B O R AT O R Y R E P O R T A N G L E D A B U T M E N T
Svein Thorstensen, MDT Dental Studio, Oslo, Norway
New Components – Same Procedures
The Angled Abutment by Astra Tech will help the dental team in achievingoptimal esthetic and functional restoration. It is used for screw retainedprosthetics and gives the clinician total freedom for placing the abutment,in 360° rotational freedom.
SummaryThe Angled Abutment is a valuable newaddition to the Astra Tech Dental ImplantSystem. It has several advantages overexisting abutments:• The abutments can be placed with
360° rotational freedom.
• It is adaptable to multiple clinical situ-ations.
• It prevents the necessity for holes in thebuccal veneer of the crown.
INSIGHT #4:2:2001 17
abutment replicas in the impressionpick-ups to transfer the angled abut-ment position to the working model.The replicas are secured with theguide pin in the designated pick-ups.Hold the replica with a plier in a firmgrip when tightening the guide pin.In this way, rotation of the pick-up in the impression material is avoided. If the replicas cannot be placed dueto divergence, it is possible to grinddirectly on the replicas to make surethat they are not in contact. Fabricatethe working model with a removablegingiva modeling material and ahigh quality stone material.
Wax up and try-inRegular working procedures forscrew-retained restorations can beused when working with angledabutments. By using angled semi-burnout cylinders, a wax-up withprefabricated teeth can be created.When the wax-up is completed, afacial occlusal impression is taken on
the construction as a reference. The construction is sent to the clinicfor try-in, allowing the clinician tocontrol the position of the angledabutments. A bite registration can alsobe carried out. This gives the first indication how to fabricate the con-struction, which has to meet theesthetic and functional requirements.
Temporary bridgeTemporary restorations give us use-ful information. A successful tem-porary restoration builds the founda-tion for a successful final restorationwith satisfied patients and few recalls.
Final restorationThe semi-burnout cylinders areattached to the angled abutmentreplicas by using the bridge screws.The plastic sleeve on the cylinders isadjusted to fit the clinical situation.Fabricate the framework by applyingwax to the cylinders. After the wax-up is completed the framework is
invested, casted and devested, usingregular working procedures.Carefully remove the bulk of invest-ment with devesting scissors. Blastthe metal framework with glass-beads. Remove residual investmentin the cylinder base by using a pick-ing agent (e.g. hydro-fluoric acid oralternative). Make sure the screwchannels are free from investmentand nodules. The porcelain is thenapplied using traditional workingprocedures.
For further information on handling procedures, the “CreatingPassive Fit” manual, based on theUni Abutment, can also be appliedfor the Angled Abutment.
1. Angled Abutment Replicas placed inthe working model.
3. A wax-up with prefabricated teeth isfinished for the first try-in.
5. Make sure the screw channels arefree from investment and nodules.
6. Final restoration with occlusally andpalatally placed screw holes.
2. The final working model with Uni Abutment Replicas and the newAngled Abutment Replica.
4. Complete wax up for the final restoration.
18 INSIGHT #4:2:2001
The Astra Tech DocumentationSummaries, Volume 1, contains 15summaries of articles that have beenpublished in highly respected implantjournals. They have been summarizedby Dr Michael Norton, UK and coverdifferent aspects of the Astra TechDental Implant System, presentingboth pre- and clinical results.
Biomechanical papers included inVolume 1 cover such issues as thecomparative strengths of the ConicalSeal Design™ and a flat top hexsystem, stress distribution along theimplant neck and different aspects ofthread design. Comparison is alsomade between TiOblast™ surface andmachined surfaces. Dr Abrahamssonand co-workers have analyzed theperi-implant tissues surrounding sub-merged and non-submerged AstraTech implants and they documentthe Astra Tech Dental Implant
System as successful in both one-and two-stage situations.
Also in Volume 1, treatment oftotally edentulous patients with fixedprostheses as well as overdentures isdescribed in two separate 5-yearstudies. Comparing fixed prosthesisattached to Astra Tech or Brånemarkimplants, professor van Steenberghepresents the 2-year results of a 5-yearprospective split-mouth study, whileDr Åstrand reports the 1-year resultson totally edentulous patients treatedwith fixed prostheses. The successfulmaintenance of marginal bone isillustrated in a prospective 5-yearstudy of the Fixture ST headed byprofessor Richard Palmer, of GuysHospital, London. Another paperfrom the same center compares theclinical, radiographic and microbio-logic results from Astra Tech andBrånemark implants.
If you would like to keep updated on the recent scientific literatureinvolving Astra Tech implants, theAstra Tech Documentation Summarieswill quickly increase your know-ledge. To order the DocumentationSummaries, please contact your localAstra Tech representative or e-mailus at [email protected].
All original articles are availableas reprints through Astra Tech.
Keep Updated withScientific Literature
Mia Jensen, DDSClinical Information Manager, DentalAstra Tech AB
Do you find it difficult to keep updated with the latest scientific literatureon dental implants? Does it require a lot of time and effort to read anddigest the important articles you need to be familiar with?
In order to facilitate awareness of scientific articles connected to theAstra Tech Dental Implant System, Astra Tech introduces a new publication,the Documentation Summaries.
D O C U M E N TAT I O N
Astra Tech Advanced Course
The Astra Tech Advanced Implant Surgery Courses held in collaboration with the Department of Oral andMaxillofacial Surgery at the Faculty of Odontology, Göteborg University, has during the last years becomevery appreciated.
The first of two courses this year was held in March28th–30th. The course focused on live surgery demonstra-tions showing different bone grafting techniques. Onecase of maxillary osteotomy was demonstrated with inlaybone grafting according to a technique developed by pro-fessor Kahnberg, who also is responsible for the course.
Sinus lifting procedures with bone grafting fromdifferent sites was included as well as fixture installations
and abutmentconnections ingrafted cases.
Clinical andexperimentalstudies onbone graftingtechniqueswere presented
and updated the attendants on recent scientific docu-mentation.
The participants, oral surgeons from Italy, were verysatisfied with the course and appreciated the interestingclinical demonstrations as well as the pleasant atmos-phere at the department.
INSIGHT #4:2:2001 19
SEPTEMBER 12-16 AAOMS, American Association ofMaxillofacial Surgeons, Annual MtgOrlando, FL, USA
SEPTEMBER 13-16 EAO, European Association of Osseo-integration Milan, Italy
OCTOBER 6-10 AAP, American Academy ofPeriodontology Philadelphia, PA, USA
OCTOBER 12-13 London 2001, International ImplantCongress London, UK
OCT. 31-NOV. 3 ACP, American College of ProsthodontistsNew Orleans, LA, USA
MARCH 14-16, 2002 AO, American Academy of Osseointeg-ration, 17th Annual Mtg, Dallas, TX, USA
Calendar 2001Insight Vol. 4, Iss. 1
[email protected] +46 31 776 30 12 The Insight Editor, Astra Tech AB,P.O. Box 14, SE-431 21 Mölndal, Sweden
DenmarkAstra Tech A/S, Husby Allé 19, DK-2630 Taastrup.Tel: +45 43 71 33 77. Fax: +45 43 71 78 65.
FinlandAstra Tech Oy, PL 96, FI-022301 Espoo.Tel: +358 9 8676 1626. Fax: +358 9 8044 128.
FranceSociété de Matériel Médical, Astra Tech France,Groupe Pharmaceutique AstraZeneca, 1, rue de l’Union,TSA 90002, FR-92843 Rueil-Malmaison Cedex. Tel: +33 1 41 39 02 40. Fax: +33 1 41 39 02 44.
GermanyAstra Tech GmbH, An der kleinen Seite 8, DE-65604 Elz.Tel: +49 6431 9869 0. Fax: +49 6431 9869 30.
ItalyAstra Tech S.p.AVia M. Luther King n. 38/2, IT-40132 Bologna Tel: +39 051 641 6511. Fax. +39 051 641 7742.
The NetherlandsAstra Tech BV, Signaalrood 55, NL-2718 SG Zoetermeer.Tel: +31 79 360 1950. Fax: +31 79 362 3748.
NorwayAstra Tech AS, Postboks 160, N-1471 Skårer.Tel: +47 67 92 05 50. Fax: +47 67 92 05 60.
SpainAstra Tech S.A., Calle Ciencias nº 73 derecha. Nave 9, PolígonoIndustrial Pedrosa, ES-08908 L´Hospitalet de Llobregat.Tel. Servicio al cliente: +34.902.101.558.Tel: +34.932.643.560. Fax: +34.933.363.231.
SwedenAstra Tech AB, P.O. Box 14, SE-431 21 Mölndal.Tel: +46 31 776 30 00. Fax: +46 31 776 30 10.
United KingdomAstra Tech Ltd., Brunel Way, Stonehouse, Glos GL10 3SX.Tel: +44 1453 791763. Fax: +44 1453 791001.
USAAstra Tech Inc. 430 Bedford Street, Suite 100, Lexington, MA 02420.Tel: +1 781 861 7707. Fax: +1 781 861 7787.
JapanAstra Tech Division,AstraZeneca K.K. Tokyo Regional OfficeKoraku Mori Bldg. 18F, 1-4-14, KorakuBunkyo-ku, Tokyo 112-0004.Tel: +81 3 5840 1113. Fax: +81 3 5840 1151.
Other MarketsAstra Tech AB, Export Department, P.O.Box 14, SE-431 21 Mölndal, Sweden.Tel +46 31 776 30 00. Fax +46 31 776 30 23.
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