Endodontics

A new rubber dam frame des ign-Easier to use with a more secure fitMarcus Oliver Ahlers, Dr med dent'

The application of the rubber dam (dental dam) is indicated in endodontics and for restorative dental treat-ments involving the acid-etch technique.The frequency of the technique's use varies significantiy accord-ing to individual circumstances, and is generaiiy too iow given its advantages. One possible reason tormany dentists' reiuctanoe to use it could be frustrating results in the past with technically difficult applica-tions. Such conditions arise, for example, when the taut rubber dam sheet exerts too much puil on the rub-ber dam clamps, causing them (and the entire rubber dam) to come loose, Particuiariy susceptible hereare clamps attached to molars. This undesired tension resuits from stretching the rubber dam material—anecessary step—for attaching the sheet to the traditional rubber dam frame. As an alternative, a neweasy-to-use rubber dam frame (Safe-T-Frame) has been developed that offers a secure fit without stretch-ing the rubber dam sheet, instead, its "snap-shuf" design takes advantage of the clamping effect on fhesheet caused when its two mated frame members are firmiy pressed together. In this way the sheet is se-curely attached, but without being stretched. Held in this manner, the dam sheet is under less tension, andhence, exerts less tugging on clamps—especially on those attached to molars. Even in cases where thereare no distinct anatomic undercuts, this lack of tension in the sheet eases isolation procedures and per-mits the use of standard rubber dam clamps. As a further benefit, the frame's raised edging provides abarrier around the sheet, whioh prevents small amounts of fluids from escaping. This contributes to greaterpatient romfort, (Quintessence int 2003.34:203-210)

Key words: dental dam, endodontics, restorative dentistry, rubber dam frame, rutjber dam holder

Even more than 100 years after the invention of therubber dam by Bamum, this isolation method is

still up-to-date,'- The number of original research arti-cles and case studies on the rubber dam tecbniquelisted in Medline Indicates increasing interest in thistechnique. The reason for this may be that dentaltreatments that require absolute dryness of the work-ing area are becoming more important:

• At tbe beginning of the iast century, Black^ in theUS and later Preiswerk* in Germany called for thesystematic application of the rubber dam for en-dodontic measures. The main priority then was en-dodontic Isolation against fluids and microorganismcontaminants in the oral cavity. The validity of thisconcern remains unchanged

'Assistant Professor, Department of Restorative Oentistfy and PreventiveDenlistry, School of Dental Medicine, University Clinic Hamburg-Epperdorf, Hambuig, Germany.

fleprint requests: Dr M. Oliver Ahlers, Department of Restorative andPreventive Dentistry, Clinic ot Dentistry, Universitätsklinik urn Hamburg-Eppendorf, Martinistrasse 52, 20251 Hamburg, Germany, E-maii:Ahlers @UKE,Uni-Hamburg,de

Added to this is the need to protect the patientagainst accidental aspiration or ingestion of smallendodontic instruments. According to court rulingsin many countries, such occurrences often are con-sidered avoidable, and tberefore can be attribttted tonegligence on the part of the dentist,"'" For protect-ing botb tbe patient and the dentist, the most recentguidelines of the German Dental Association(DGZMK) recommend the routine use ofthe rubberdam for endodontic treatments,"An additional restorative application field requiringabsolute dryness has come to be with the increaseduse of tbe acid-etch technique, A review of pub-lished chnical resuhs of such treatment with andwithout a rubber dam has not, however, providedconciusive proof that this isolation technique is su-perior to others in ensuring the long-term ciinicalsuccess of these types of restorations and that there-fore, the use of tbe rubber dam is indispensable forthem. Nonetheless, the authors of these reviewsagree tbat the rubber dam technique offers clear ad-vantages for stich procedures,'^"In view of new diseases with potential for infectionduring dental treatment, the rubber dam gains added

Quintessence International 203

• Atilers

significance as a simple and clear-cut prophylacticmeasure against infection, "-'',

Despite these factors, the use of the rubber dam stiilhas not established itself to any great extent in manycountries. Commonly considered responsible for thisaversion to the rubber dam is inadequate training andthe resultant great amount of time needed for itsuse"'"-though even inexperienced students have beenshown to need oniy around five minutes for it,"*

Other, up to now, less recognized factors contribut-ing to current reservations about using a rubber damare frustrating experiences early on with technically dif-ficult apphcations, A typical problem, viith which regu-lar users of the rubber dam technique are famiUar, isthe frequently inadequate retention of the rubber damon molars. This arises because of the great amount oftension created when the rubber sheet is stretched ontothe frame. This tension, in turn, can exert such a tug onthe rubber dam clamps that, under adverse conditions,the whole rubber dam can spring loose.

The new rubber dam frame discussed here solvesthis problem by allowing for the secure attachment ofthe dam to the frame without requiring it to bestretcbed. In this way, no tension is created by the as-sembly of the rubber dam and its holder, considerablyreducing elastic tension tugging on the clamps.

METHOD AND MATERIALS

History of ttie rubber dam frame

Several developments of the rubber dam frame designhave been published since the account of the metalframe attributed to Young,' For example, McConville'*and later SbaneF" presented enbancements to the ba-sically uncbanged U-formed frame by Young, In com-parison to this, tbe development of the metai foldingframe hy Kahn was a significant innovation, whichwas later followed by a plastic folding frame with twohinges developed by Sauveur, '̂-'̂ The objective of thefolding mechanism introduced in both cases was toenable easier access to tbe oral cavity under the rub-ber dam for taking periapical radiographs.

Another field of further deveiopment is related to thematerial used in manufacttiring the rubber dam frame.Whereas the traditional metal frame developed byYoung was made of radiographically opaque steel (Fig1), various frames made of plastic have been introducedin the recent past. These first resembled in their shapethe traditional U-formed metal frame {Starlite Visiframe;Hygienic Master 6 [ColteneAVhaledent]) (Fig 2). In ad-dition, there was the polygonal nylon frame by

Nygaard-0stby known as the "shark mouth" (SvenskaDental Instruments) (Fig 3}. Other frames based on theSauveur folding frame design mentioned above wereusing various types of plastic depending on the manu-facturer (Cadre de Digue; Roeko) (Figs 4 and 5).

The problems mentioned earlier regarding the useof the rubber dam for restorative and endodontic ap-plications on lateral teeth are not mitigated by any ofthe frame modifications mentioned above. This is be-cause the mechanics of attaching the sheet to theframe with tension remain in effect unchanged,

Deveiopment of a new rubber dam frame

Underlying the new development̂ ^-^^ presented herewas the goal of combining the advantage of usingradiographically translucent plastic for endodontictreatments, with easier and more secure use on lateralteeth,

• In regard to practical use, the author noticed duringnumerous undergraduate and continuing dental ed-ucafion courses that less experienced users had par-ticular difficulty pulling hoth sides of the rubber dammaterial over the stubs on the outer ends of the con-ventional rubber dam frame, while at the same timekeeping the frame firmly in hand (Fig 6),

• In order to ensure more secure retention, it ap-peared necessary to reduce the tautness of the dam,and consequently the tugging pressure exerted onthe rubber dam clamps, especially for the isolationof premolars and molars.

Because stretching tbe sheet over the frame con-tours is difficult and furthermore Is responsible for theundesired tension effect, a new means of attaching thedam to the frame appeared to be necessary. Afterpreattached frame/dam combinations (eg, Quickdam[formerly by Ivociar Vivadent]) were not successfullyadopted, it was decided that the new frame sbould bedesigned to work witb commonly available dentaldams in tbe standard format ( 6 x 6 in; 15,4 X 15,4cm). Furtbermore, it should he compatible with nor-mally available sheet thicknesses (light, medium,heavy) made of various materials by various mantifac-turers, and should be autoclavable.

These considerations gave rise to a workable solu-tion that replaces the conventional one-piece framewith a two-piece frame design. The Safe-T-Frame{Sigma Dental Systems) is composed of two hingedframe members whose snap-shut locking mechanismsecurely clamps the rubber dam sheet in place (Fig 7).This concept aiso makes it possible to retain the tradi-tional U-formed frame geometry and dimensions.

204 Volume 34, Number 3, 2003

• Ahiers •

Fig 1 I-QJ i.;.r,a. u-rci-.-i-ieo (uaber(rame Dy Young made of metal

Fig 2 Hyg.enic Masier 6 U-tormed rubberdam ¡rame made ot piastic.

Fig 3 Polygonal plastic frame nicknamedthe "shark moutln."

Fig 4 Oval plastic folding frame bySauveur (Cadre de Dique).

Fig S Oval plastic folding frame bySauveur (Roeko).

Fig 6 Slipping the stamped and perfo-rated rubber dam sheei over a frame hav-ing conventional geomerric dimensions.stretciiing first over the stubs on the frame'send-points secures the attachment of thesheet to the trame. This step often is con-sidered difficult.

Use of the frame for anterior teeth

The use of this new frame draws on the concept ofshifting as many work steps as possible into tbepreparatory phase prior to ihe placement of the rubberdam into the patient's mouth. This requires that clini-cal placement not occur before fhe dam is securely at-tached to the frame.

As long as conventional templates are used to markoff tooth positions on the sheet where perforations areto be later made (using stamps or stencils), this step ismost effectively completed initially before attachingthe dam to the frame.

For assembly, the frame is first set fiat on an evensurface and opened up using both hands (Fig 8). Thepreviously stamped rubber dam sheet is tben laid ontbe Iower member of the opened frame such that theupper edge of the sheet extends to just below the twohinges (Fig 9}. Because the frame is scaled so thatstandard-sized sheets will adequately fill out beyondthe outer edge of the frame, correct and reproduciblepositioning is easily attained. Next, the frame is closedby first pressing the top member of the frame downonto the mated lower member (Fig 10). The sheet is

^^MFig 7 The Sate-T-Fra-hinged foiding frame.

U-tormeO plastic

now clamped securely in the frame, and theframe/sheet assembly is ready to be placed in tbe pa-tient's moufb (Fig 11). In situafions wbere the isola-fion area is fo remain limited to just one tooth (eg, forendodontic work on lateral teeth), a rubber damclamp with wings can be fitfed into the prepunchedsheet in advance (Figs 12 and 13),

The actual placement of the rubber dam assemblycan be handled by a single person as long as only onetoofb is to be isolated in tbe manner described.*''^Iflarger areas are to be isolated, as is generally the case

Quintessence International 205

• Ahiers

Fig S Using both hands to open the Fig 9 Piacement of the premariied rubber3afe-T-Frame, whicin should be set out on a dam sheet (ivory Premium Dam, iHeraeus-fiat surfaoe, Kuizer) onto the opened Sale-T-Frame.

Fig 10 Preiiminary or final ciosing ol therubber dam trame by using iight or heavypressure above the bottom grip.

Fig 11 Atter tirmiy pressing the tramohaives together, the sheet is now fixed se-oureiy between them, without tension, evenin the area next to the bottom grip.

Fig 12 Piacement ol the rubber camframe with a iooseiy heid ciamp lor isoiat-ing a iower right molar tor endodontic treat-ment

Fig 13 Atter supping the rubber dam overthe ciamp wings, the isoiated tooth is readyfor treatment (piacement accompiished de-spite minimai anatomic undercuts and in-advertentiy ieaving a iayer of rubber dammateriai between the ciamp and the tcothsurtace).

with anterior teeth or during treatments using theacid-etch technique, tbe placement is best accom-piisbed using teamwork, Tbis can be illustrated usingtbe isolation of tbe entire maxillary anterior area as anexample:

After appropriate preparation (as described above),a slight amount of lubricant is spread around the per-forations on the dam now secured to the fratne.Vaseline (Unilever) is not suitable for tbis because itleaves an undesirable film on tbe isolated tootb sur-faces, and because it can barm the rubber dam sheetitself. Instead, a flavorless water-soluble lubricantsbould be used wbicb is explicitly approved for intrao-rai use (designated a "medical product" as requiredtoday [Dentaglide, DDS Front Office]), The preparedrubber dam assembly is tben positioned in tbe pa-tient's moutb beginning from tbe side furthest fromthe dentist {Fig 14), It is first slipped over the distaltooth to he isolated (Fig 15).

Directly after this, the rubber dam sheet is securelyattached to the distal isolated tooth using the appro-priate rubber dam clamp. Attachment to premoiarsmakes clamp choice and fit easier because tbese teetb

provide sufficient retention for universal premolarclamps (No, 2 or 2A [Ivory, Heraeus-Kulzer]), Afterattaching tbe first clamp, tbe rubber dam can nolonger slip loose, Tbis makes tbe next steps in guidingthe sheet over the other teeth to be isolated consider-ably easier (Fig 16),

The following process of feeding the rubber damsepta tbrougb tbe individual interproximai contactpoints is greatly facilitated by tbe prior application oftbe lubricant to the bottom side of tbe rubber dam ma-terial. If guiding tbe rubber tbrougb is at first difficultin certain points, these can be ignored for the timebeing; later correction is easier once tbe rubber dam iscompletely in place.

In the meantime, the dental assistant proceeds witha second rubber dam clamp. It is opened with rubberdam clamp forceps and then applied in the same man-ner to tbe distal tootb to be isolated on the side closestto the dentist (Fig 17), The rubber dam is now com-pletely in place and fully able to meet tbe demands ofisolation for endodontic applications (Fig 18),

For restorative appUcations it is a good idea at tbistime, as pointed out above, to make the necessary

206 Vciume 34, Number 3, 2003

• Ahlers

Fig 14 Aner proper preparation (anach-ment of ttie stenciled dam material to theffame, punching out the necessary perfora-tions), ttie rubber dam is quickly appliedwitti teamwork.

Fig IS Beginning me application ol therubber dam on the side furthest from thedentist (on the assistants side) with the dis-tal tooth to be isolated (in this case themaxillary lett first premolar).

Fig 16 "Knifing" the dam's septa throughthe aoproximal spaces of the maxillary an-terior teeth to be isolated after applicationof a suitable lubricant to the "shiny" bottomside of the sheet.

Fig 17 Attachment of a second rubberdam clamp on the distal tooth to be iso-lated on the side closest to the dentist.

Fig 18 Rubber dam completely in placebetween the maxiiiary left and right firstpremolars using two standard 2A rubberdam clamps.

Fig 19 Correction at the cervical positionof the rubber dam sheet on individual ante-rior teeth to be treated using dentai ¡loss

cervical adjustments to the sheet's fit. Where approxi-mal contact points earlier resisted entry of the rubberdam septa, dental floss can now be used to gently"coax through" the rubber (Fig 19). In some cases,(eg, due to soldered joints) it may instead be neces-sary to exclude certain interproximai spaces. Forthese, tbe necessary septa sbouid be cut out of tbesheet witb a small pair of scissors prior to tbe dam'splacement in the patient's mouth. After the corre-sponding correction of the cervical position, the rub-ber dam is now complete and ready for use in restora-tive treatments using adhesive techniques (Fig 20).

The perspective view of the rubber dam set up in tbismanner reveals that in its locked position, the frame'sedge is raised above tbe sbeet (Fig 21). Tbis design ele-ment is intentional in order to prevent small amoimtsof fluids from escaping onto tbe patient (Fig 22).

Use of the frame for iaterai teeth

For tbe isolation of molars, the new frame design al-lows for precisely altering the position of the rubberdam sheet prior to the final snap-tight closure of the

upper and lower members. This is accomplished sim-ply by bolding the already loosely sbut frame in onehand near the bottom grip while using tbe Index fingerand tbumb of tbe other hand to pull the dam betweenthe two frame members in toward the center of tbeframe (Fig 23). Finally tbe two balves of tbe frame arefirmly snapped togetber in the overlapping area be-tween the horizontal bottom part of tbe frame and tbetwo vertical frame arms. At tbis point no "accident"can occitr: According to tbe manufacturer, tbe frame'sfiberglass-reinforced plastic construction renders it in-destructible during normal use (Fig 24).

Prepared in tbis way, tbe rubber dam is now ap-plied to tbe patient in principally tbe same manner de-scribed earlier.

For the isolation of individual (pre-)molars prior totheir endodontic treatment, it may make sense to useonly a single clamp for isolation. The clamp can bepositioned witbin a given peti'oration in tbe dam be-fore its placement in the patient's mouth (see Fig 12),making it possible to apply the frame, the dam itself,and a clamp in one work-step without assistance (see

Quintessence International207

• Ailiers

Fig 20 Rubber dam positioned ready for Fig 21 The perspective view ot the com- Fig 22 The frame's raised border edgingsubsequent restorative treatment on maxii-iary anterior teeth

pleteiy piaced rubber dam shows that theframe, using the conventional arrangementof punched holes, is correctly positionedunder the nose. Moreover, it can be seenthat the frame torms a ciearly raised ridgeabove the surtace ot the lubber dam sheet.

as weii as the watei-tigiit ciamping mecha-nism, ensures that smailer amounts ofwater do not accidentaliy escape, ensuringsufficient protection even without the cre-ation of a "pocket" in the rubber material asdone with conventional frames.

Fig 23 Ad|usting the position ct the rub-ber dam siieet between Ihe twc framehaives by puliing the sheet toward the cen-ter ot the frame prior to firmly piessing theupper and iower frame haives together.

Fig 24 in the end, the frame must beIccked in the ciosed position with pressurenew appiied to the outer adges at the bot-tom of the frame arms near the grip, smalimarkings underneath the grip aid in this.

DISCUSSION

Rubber dam indication

The indication of the rubber dam tecbnique for tbe ap-plications described above remains indisputable. Eventhough scientific studies have not been able to provethat these applications are not feasible without using arubber dam, this does not change the fact that its useoffers considerable advantages to botb the patient andthe dental team,'^" Furthermore, recent studies haveaddressed the issue of patient comfort in treatmentswith and without using a rubber dam. Interestingly,the authors demonstrated that from the patient's pointof view, the use of the rubber dam significantly in-creases comfort during treatment,^^ In addition, usinga rubber dam can actually save time." For these rea-sons, it is desirable to overcome the various barriersagainst the use of the rubber dam for the correspond-ing indication areas. Where technical obstacles areconcerned, technical solutions must be found.

For the difficulties discussed regarding inadequateretention for lateral teeth, a number of solutions and

ideas have already been proposed. These have focusedon increasing the dam's retention at tbe sheet's ten-sion point (eg, the tangential connection with thecombined surface of the rubber dam clamp and iso-iated tooth). Efforts in this regard have resulted in thedevelopment of virtually countless numbers of vari-ously shaped rubber dam clamps. From the dentist'spoint of view, though, this course has been problem-atic for a number of reasons:

• It is difficult to obtain a clear overview among thevariety of clamps, a situation fostered by tbe unsys-tematic numbering systems developed over time bythe different manufacturers-particularly since sev-eral clamp makers (Ivory/Sigma Dental Systems-Emasdi, Hygienic/Coltene/Whaledent, HuFriedy,Ash, Roeko) use different designations for essen-tially the same clamps.̂ *'

• In addition to this practical limitation, the conceptitself is an issue because it basically involves a sys-tem of clamps of increasing tension and/or square-edgedness. Because it has been shown tbat damageto the dental hard tissue by rubber dam clamps is

208 Volume 34, Number 3, 2003

possible due to suboptimal positioning, especially inthe root area,'^ such increases in the clamp's tensionforce, or the increase in the number or size of theclamp's beaks, must be regarded with caution.

Other alternatives, such as the replacement ofspring-tension clamps by tensioniess resin-bondedwings attached to the tooth to be isolated through theacid-etch technique,̂ *- are at least temporarily invasiveand require more effort,

Evaiuation of the new frame

Against this background, it appears reasonable to ad-dress the source of this series of problems instead ofthe effects-in other words, to seek where possible toavoid creating the unnecessary and undesired tensionin the rubber dam sheet in the first place. Reducingdie elasticity of the dam material itself does not appearto be practicable here. This is because a certain levelof elasticity is necessary to facilitate intraorai adapta-tion to individual conditions, and in order to avoid thetugging effect on the clamps without some amount ofdamping or "give" in the sheet material.

Another conceivable approach would be to changethe geometric shape of the dam, which up to now hasbeen available in roUs or precut quadrants. This couldallow a reduction in the elastic forces, particularly inthe middle part of the isolated area. Countering thisidea, though, is that with any of these changes, a se-cttre fit with conventional frame types could not beguaranteed. Furthermore, such sheets are currentlynot available, and according to the latest proposal ofthe American Dental Association's Working Group 90(in which the author is a participant), there are noplans to develop them.

With these issues in mind, it appears that the mostpromising approach is through changes ¡n framegeometry, whicb minimize the tension in the rubbersheet after attachment to the frame, A conceivable ap-proach for achieving this would be to draw or "bow"the central section of the frame inwards. This idea alsofails, however, because with such a bent frame design,no secure attachment of the dam to those pins placedin the frame's bowed middle section can be guaran-teed. Additionally, this format undesirably reduces theaccessible working area.

An alternative in this connection is to adopt a newsystem for attaching the dam to the frame. This ideafirst attracted attention when a variety of preattachedframe/sheet combinations were heing developed,̂ '-̂ *None of tbese systems, however, were able to establishthemselves successfully.

Ahlers -

The proposal presented bere, on the other hand, isbased on a frame having new geometric dimensionswhich works in combination witb standard-sized damsheets. The only new demand its use makes is that theapplication must follow the procedure described inthis article-an approach calling for first attaching theproperly prepared dam to the frame prior to place-ment in the patient's mouth. Other techniques (eg, set-ting a rubber dam clamp intraorally on the isolatedtooth, followed by intraorally slipping the perforateddam over the entire clamp and the isolated tooth, andultimately attaching the fi-ame to the dam now securedin the patient's mouth) are in any event linked withgreater time and work effort for the dental team, andmore discomfort for the patient,^« In contrast, themethod presented here is a basic one whicb simplifiesapplication of the rubber dam, and hence, serves topromote the use of this effective tool.

Practice has shown that increased efficiency isachieved by having a number of frames outfitted withdarns marked and perforated for various indicationsand ready for immediate use. This decreases the preptime for applying the rubber dam down to zero, and indoing so helps overcome reservations in tbe dental of-fice against this presumably fime-constoming measure. Ithas also been proven effective to apply this rubber damsystem at the earliest possibie point in treatment, and toeven carry out endodontic trepanation measures be-neatb it. Tbe necessary evacuation of fluids can also bedone with the dam fully in place. The design of tbe newframe witb its raised edging confines small amounts ofescaping fiuids; the frame's clamping mechanism re-mains sufficiently watertight throughout treatment.

Perspective on future developments

This innovation is particularly important in view of itsapplication in restorative treatments using theacid-etch technique. It offers a framework for makingthe use of the rubber dam even simpler, and henceovercoming inhibitions about its use rigbt at tbe start.

In regard to endodonfic treatments, one probiemfor which an optimal solution has not yet been foundconcerns the interaction between tbe rubber dam andradiograpb machine. Various proposals have beenpuhlished on this, but none have been completely con-vincing. Temporarily removing tbe complete rubberdam for taking radiographs does not appear to be anefficient solution. The alternative of leaving only thedam in place hut completely or partially removing therubber dam frame^"' has proven to be even less of ananswer. Furthermore, it can result in discomfort andembarrassment for tbe patient, particularly when theendodontic treatment area is located separately fromthe radiograph equipment.

Ouintessence International 209

• Ahiers

The plastic folding frame by Sauveur^^" [see Figs 4and 5) offers a promising alternative in tbis regardeven though, here too, difficulties remain. An article''"reported that "with this frame ... wben snapping itshut a strong tug on the rubber dam clamp wasnonetbeless exerted by the rubber sheet."

Because the frame introduced here does not stretchthe rubber dam itself, the frame/dam assembly in itsapplied state provides greater sideways mobility thanresults with other techniques. In endodontics, thismakes it possible to posifion the radiograph film intra-oraily with the corresponding film holder in basicallythe same manner as when using the folding frame.̂ 'This also enables its use in combination wifh tbe cur-rently used radiograpb film bolder (EndoRay II,Dentsply/Rinn), as well as witb future products.''"

REFERENCES

1. Kamann W. Die Geschichte des Kofferdams. ZWR 1996;105(9):498.

2. Glenner RA. The rubber dam. Bull Hist Dent 1994;42:33.3. Blatt! GV, Operative Dentistry. Chicago: Medico-Dental

Publishing, 1908.4. Preiswerli G. Lehrbuch und Atlas der konservierenden

Zahnheiikunde. München: J.R Lehmann's, 1912.5. Beer R. Antihaifterielie Therapie in der Endodontie. Die

Quintessenz 1991;1I:1739.6. Guldener PHA. Endodontologie. Stuttgart: Thieme, 1987,7. Pecchioni A, Rouiet JF, Lavagnoii G. Die Verwendung des

Kofterdams. Tn: Pecchioni A (Hrsg). Die Wurzeikanai-behandiun-Eine praktische Anleitung fur Studierende undPraittiker, Beriin; Quintessenz, 1982:61,

8. Weine R Endodontic Therapy. St Louis: Moshy, 1982,9. Hulsmann iVl, Juristische Probleme in der Endodontie, En-

dodontie 1995;4:93.10. Lampert F. Zwischenfälle in der Endudonlie und ihre foren-

sische Bedeutung. Zahnarzti Weit Zahnärztl Rundsch ZWRZahnarzt) Reform 1977;86:667

11. Deutsche Gesellschaft für Zahn- iVlund- und Kieferheiilunde(DGZMK) sowie die Deutsche Gesellschaft für Zahnerhal-tungskunde (DGZ) bearbeitet von Schäfer E: Wurzeiitana-laufbereitungen (gemeinsame Steilungnahme der DGZMKund der DGZ). Dtsch Zahnarzti Z 2000;55:735.

12. Hici<el R. Der Kofferdam-Nach wie vor Notwendigkeit?PhiihpJ1997;14:363.

13. Kamann W. Kofferdam-Wandel von Indikation und Tech-nik [The rubber dam-The change in indications and tech-nic]. Schweiz Monatsschr Zahnmed 1998;108:77L

14. Marshail K, Fage J. PDI Infection Control Checklist. FDIWorld 1997;6:20.

15. Wong RC. The rubber dam as a means of infection controlin an era of AIDS and hepatitis. J Indiana Dent Assoc 1988;67:41.

16. Saunders WP, Chestnutt IG, Saunders EM. Factors influ-encing the diagnosis and management of teeth with pulpaland periradicular disease by general dental practitioners.Part 2. Br DentJ 1999;187:548.

17. Simonsen RJ. Kofferdam, Stiefitind der Zahnheilkunde. DieQuintessenz 1991;42:1203.

18. Baltadyian H, Mahseredyian S. Time taiten to position arubber dam by fourth year dental students at the Universityof Montreal [French]. J Can Dent Assoe 1992;58:228.

19. McConvillc RS, Rubber Dam Frame. US Patent 3,406,452,22 Oct 1968,

20. Shanei KA. Hoider for Rubber Dentai Dam. US Patent4,583.946, 22 Apr 1986.

21. Kahn H. Rubber Dam Holder for Use During EndodonticTherapy, US Patent 4,204,329. 27 May 1980.

22. Sauveur G. Improvement of the rubber dam frame, J Endod1997 ;23:765-767,

23. Sauveur M-G, Dam Frame for Use During EndodonticSurgery. US Fatent 4,820,155, 11 Apr 1989,

24. Ahiers MO, Kofferdamhaiter. Deutsches Fatent- undMarkenamt DGBM 298 13 627.9 (1998).

25. Abiers MO. Rubber dam bolder. Europäisches Patentamt -Office européen des brevets - European Patent Office 99114 557.4-2310(1999).

26. Ahiers MO. Rubber Dam Holder. US Patent 6,299,446 BL9 Oct 2001.

27. Guidener FHA. Kofferdam (Spanngummi). In: Schroeder A(Hrsg). Endodontie-Ein Leitfaden für Studium und Praxis.Berlin: Quintessenz, 1977:108,

28. Ahlers MO. Die Anwendung von Kofferdam in der moder-nen Zahnheilkunde (Serie Abteiiung fur Zahnerhai-tungsitunde und Parodontologie, UniversitatskrankenhausEppendorf,. Selbstverlag/Lehmanns Fachbuchhandlungen,Hamburg, 1995.

29. Kamann W, Kofferdam-Bewährtes und Neues. ZWR 1995;104:640.

30. Winkler R, Kofferdam in Theorie und Praxis. Beriin: Quin-tessenz, 1991.

31. Zeppenfeld W. Fraxisgerechte Kofferdamtechnii(. ZahnärztlMitt 1990;80:1486.

32. Schriever A, Eißner D, Heidemann D. Kofferdam aus Sichtdes Patienten. Die Quintessenz 1993;49:247.

33. Kimmel K-H. Kofferdam: Von der Lehre gefordert -von derPraxis (noch) ignoriert. Zahnarzti Mitt 1998;88:78.

34. Coitene/Whaiedent Oniine. Hygienic Dental Dam ClampConversion Chart. Available at: http://v;Tvw,eoltenewhalt-dent.eom/damchart.htm. Accessed: June 5, 2001,

35. Kamann K, Rasterelei(tronenmii(roskopische Untersuchungzur Wirkung von Kofferdam klammern auf die Zahnober-fläche. Endodontie 1996;4:277

36. Herrin HK. Method and apparatus for securing a rubberdam. Europäisches Patentamt Office européen des brevets -European Fatent Office EF 0294 230.1988.

37. Barasz SG. Dentai Dam with Integral Deformable Erame.US Patent 4,721,465. 26 Jan 1988.

38. Hesselgren S-G. Arrangement for Separating an Area ofOperation or Treatment in the Oral Cavity. US Patent3,781,994. 1 Jan 1974.

39. Hulsmann M, Endodontie (Serie Dent-Praxis). Stuttgart:Thieme, 1993.

40. Ahiers MO, Stoica E, Flatzer U. A novel fiimholder for en-dodontic X-rays compliant with rubber-dam application. JDent Res 2001;80(spccial issue):643.

210 Volume 34, Numbei 3, 20O3