Balanced Semi Static

8/2/2019 Balanced Semi Static

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T 111; iml)rcssion technique herein described may he termed a balanced semistaticinipression procedure for a normal, healthy, etlentulous maxilla. \Vith sonicmodification, it is basically the same for all types o f maxillae. illthough thisimpression procedure is an integral part (Ii ;I 5\-stematic method Of nukingcomplete dentures, it can 1~ tvxxl to advantage in any technique. It is a meansOf fulfilling the impression requirements for closctl lxlatcs or palatvle5s i roofless 1dentures.

The entire theory luck Of this iml)ressic~u lxow(lwr is based 011 Our clinicalfindings which led LIS to the conclusion that tlw l;ctLaral and anterior uxlls ofthe palate are the primary stress-l)earing areas. 1 y rising an individually pre-pared tray (with the aid of \vas ), \VC nttemI)t to cilJtail1 eq~ial Materal l)ressureOn the lateral and anterior palatal walls, \vllilv \ve I,rotcct, statically, the alveolarridge area which is less able to withstand tlir lnasticatory stresses.

Some of tlic important imI)ression proc~~l~ire5 arc vithcr hased 011 cc~~~tprcssion0i the entire masilla, or the\- arc an ;ipprOacl~ 10 au all-static impression : impres-sions Iy hotli methods at-c wi~iallv lil~~sclc-trinili~ctl. Clinical lincliiigs indicatethat each of these procetl~u-es can Ixoducr similar wtl results lwx~isr lieitherIxovitles Ixotcction to the cancrlloiw 1~0~1~mitlvrl\.ing tlx. alveolar ridge. ,-Ill Oithis I)res~in~es that ait acceI~tal~le \-crtical xiitl centric rclatioii \vitli :I ~zilanwtloccltG)ll uxs Iuxvicled at tlw till!e of tlclivu\- oi tllv fillisl?etl cltltmlrtah.

\\*e feel justified ~rlieii \ve say that it \v;is i10t naturvs 0rigillal mtent 10lla\T tlw alveolar ridge \~ithst;tntl tlw lxiiliar\~ 5trt2wb ironi :I clr~itui-c l)asc~.\\lwll :I iiormal, natural tlentitioti is l~rwclit, force\ oi tulusioii are cli5triluttvl111 a Idallcctl iiiaiiner to Ihc occlusal s~iriares of tlie teeth, the roots iji . \\hicharc firnily inil~ctltletl in their sockets rlcell ii1 the 1~1tlv of the iriaxilla. I11t2:tl\~eolar hone then ads a5 ;t 1Wtrcss Or ,wco~iclar!- s~iplwrt. \Z'llCll ted 1-i at-ciost, the maiii fiinction Of tlic ;il\volar I)one i5 also lost. \Vhen the liealtvl ;il\:wl;trritlgc is used as the primar\, stress-hearing xxx, we cannot expect tlial it 11 llllc wholly successful for ii long pcriotl lxcatisc ;i ridge thus f0rmcd ii iiot a,thoroughly contlitionetl as wtne Of the other areas of tllc nlasilla. It s('t"lllS !f IUS that it is nlore logical to take advantage of and LISC the mow st:ll,ltb and COII-tlitioned part 0i the maxilla. namely, the lateral ant1 anterior palatal rvalls oithe palate.

From the day of birth onward, pressurize arc% cculstantly applirtl to lht. palate114 he tongue in its various functintis, cspcci:~lly iii the act of swallowii~~:. Thcx

Read before the American Denture Society. Chicago. ill.. Feb. 3. 1951Received for publication Aug. 27, 1051.


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AN I~IlRl:SSIOK IROCITJCRE 649lmssures so condition the ti5ucs cli the lmlate that they are al~le to \vithstantlthe stresses of a denture base far better thaii the alveolar ridge. Surgical dis-tllrl);uice of the alveolar ritlge, such as in the eradication of infection, estractionof teeth, and alveolectomy, is followed by a comparatively short conditioning(healing) time. The stability of an alveolar ridge, the tissues of which havebeeli but recently organized and conditioned, cannot compare with the stabilityof the palate which took a lifetime to establish and which was not, as a rule,disturbed by surgery. Especially is this true if a pyorrhetic condition has existedIjefore extraction. It is often two or more years before the alveolar ridge hasa mnl)lance of stability. This may be one reason why some patients have severaltlentures made over a period of a few years before one is satisfactory.

Since alveolar ridges, especially those with a history of pyorrhea, in variousstages of resorption cannot withstand the stresses, some means of protection isindicated and should be provided. This assumption is based on the clinicalobservation of many maxillae in which the ridges were unduly reduced whilethe palatal area seemed to be intact. These findings suggested the use of anarea which nature has conditioned during an average lifetime and which wascapable of withstanding stresses greater than needed for the function of mastica-tion with an artificial denture. The impression procedure presently employed1)~ the members of the C)enture Research Group of Chicago takes advantageOF the clinical findings. This procedure directs the distribution of stresses toall areas according to their tolerance.

IMore giving the actual technical procedure, we wish to mention that 110imlmssions are ever attempted before a complete case history including a idImouth x-ray e>:amination is obtained, even though the patient may be completelyrdentulous.

Surgery is resorted to only when (1) the tuberosity is bulky enough tointerfere with the freedom of the masticatory movements and (2) soft flabbymandibular tissue overlies the remnants of the ridge (to help provide a morestable denture base).

Surgery is not resorted to when a torus palatinus is present which doesnot encroach on the lateral and anterior palatal walls.

Prom the medical and dental history of the patient, objective and subjectiveexaminations, responsiveness to suggestions, conversations, expressed expecta-tions, and other sources, enough information should be acquired to classify thepatient. This knowledge will guide us in taking the necessary steps to obtainhis full cooperation. His confidence, gained earlier, must be maintained. \IThenthese factors of understanding and cooperation in both the patient and operatorare present ill the greatest degree, we reach the optimum of psychosomaticequilibrium.

The five important steps in good denture service in order of their im-portance are: (1) centric registration at an acceptable vertical dimension, (2)balanced articulation, (3) professional guidance, (4) impressions, and (5) adjust-ments.


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Fig. l.--Operator's and patient's pwilion

In this position, the operator is able to control tllc. l)clsitic,ll oi the patictits 1lCitCl\vhile he is maintaining equai bilateral pre,~s~n-~ vith the inks finger> (~1 themetal tray, thus obtaining the dwired type oi :I lmlancrtl impressitrli.

TECIlNIL)II~The technical procedure for the uplwr inlprekon is as iollowb .1. Examine the mouth for loose particle:, of food or foreign I)odies. Havethe patient rinse the mouth. Select a metal tray. the flanges of which have been


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AN IMPRESSION PROCEDURE 651shortened. This will be used as a base upon which an individual tray will be con-structed, with the aid of a red refined wax. Fig. 2 shows the essential materialsused. The metal tray should be at least s inch larger than the entire circum-ference of the maxilla, transversely as well as anteroposteriorly. The posteriorportion of the tray should extend to the hamular notches when the anteriorsection of the tray clears the most pronounced portion of the ridge by at least!,{ inch.

Fig. Z.-Essential materids.

2. Soften the narrow end of a sheet of red refined wax in a flame. Foldback twice a g inch strip o f this wax, which will develop three thicknesses ofwax. Cut this folded piece of wax from the sheet. While walking to the patient,break off and insert into the ridge areas of the dry tray, three equal parts of thissoftened wax (Fig. 3). One piece of the wax is placed in the region of theanterior midline and the other two in the tuberosity regions of the tray. Allthree pieces of the wax cover the ridge area as well as the labial and buccalportions of the tray. These three pieces of wax we call the alveolar guide blocks.I,ater they are alveolar guide forms.

3. To create the alveolar guide forms, insert the tray in the mouth and, whilestanding behind the patient, center the tray. Then press it into position withjust enough pressure to reduce the alveolar guide block wax to 50 per cent ofits thickness. Remove and check (,Figs. 4 and 5). Do not accept this step ofthe tray preparation if any portion of the metal tray shows through the waxof the alveolar guide forms. The wax which contacts the alveolar ridge shouldhe at least twice as thick as the displaceability of the tissues involved. The useof the alveolar guide forms insures the accuracy of the metal tray selectionand its adaptation since they indicate the amount of space occupied by the wax


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652

Eig

Fig.

Fig. 3.-Alreolar guide blocks before insertion.

.i.

Iqjg, .q -lnscrtion of tray to cr~aw alveolar guide forms.Fig. 5.-Alveolar guiric for!nr.


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Volume 1Kumber 6 AN IMPRESSION PROCEDURE 653at the peripheries, give positive guide for the accurate subsequent centering andseating of the tray, and indicate the thickness of wax over the ridge areas. Theaccuracy of this step will facilitate the making of a static impression of thisimportant area at the final step.4. To create the palatal guide form, soften in the flame, but do not over-heat, three-fourths of a sheet of red refined wax. Mold this wax into a walnutshape (the approximate shape and amount needed to fill the vault area of thepalate). Adapt this palatal guide block wax to the tray so that it will slightlyoverlap the most lingual portion of the alveolar guide forms (Fig. 6).

Fie. 6.

Fig

Fig. 7.Fig. K-Adaptation of the pal&al block .. 7.-The palatal guide form immediately after rexno\

Elevate the lip to aid in the insertion and centering of the tray (Fig. 4).While standing in back of the patient, center the tray, and with one quick, heavyupward pressure seat the tray into the position previously established by thealveolar guide forms. The excess wax is automatically expelled, creating thepalatal guide form by this simple operation of applying equalized pressure.


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Remove and examine carefully, making sure that the pal:~taJ g!ui[ic. ror!i-LV;~S covers all of the lateral and mterior palatal walls. It lllust ;llccI ha\.? :Iunif~oriii Mtiitling with the alveolar qitle i0rni \vax ( l;ig. 7 I. I*:(J~I:I: !,ilzttc~r:i!Jjressure in creating the palatal guide ivrill ii ni(d iiqortant. ! ~riil;~trt.;rl preisure will result in unilateral tlisplacemrnt ;A tissur? whic11, when tr:ui~ic-rrc~(l it 5the finishetl clenture, coultl casilv i)e 011r ()i the C:LIISC,S0i tlcrit~ire ill--t;il)iiitb,l;urther examination of this iiidividual trax lmpar;ttiol~ will disclose a \ ct.\ cictinilt~lmlling tlo\vn of the palatal guide wax in tllv post rl:tni area 1)~ tlit. iiivollmt;tri;tctiou of the riiusclcs ai tlw soit palaW ( Iig. i 1.

5. -1 1~~1 tlani is lm~vitletl for as . . .;L lurt oi the itrdiv1dual iilllumbi~ul I rot:This is acconq~lished hy partially chilling the wax, and then, with :L 4~~rl~. llt~atv~lknife. cutting away all excess was distal to a straight line drawn Ic\\YY~I~ J)oillt >about 2 mm. distal to the impressions d the right and left hamula~- :lotchc.s.The post tlam is now tlevt~lcq3etl 1,~ inserting ;I warm knife ldatlt 10 :L tlel~tlianteriorly of almut 3 or 5 min. into the wax rnitlway between the iiitaglio anilthe metal base, then elevatiti g the wa-x across the entire lmst tlml :~rm 11) tl?l,atnomt necessary to create an acceptalde post tlam The atnmlnl i- iiltlic.;ttr~l1)~ the resiliency of the tissl1r.i (Fig. 8, .-I ant1 x I. The post tlanl i> tciniorcvi1)~ filling in the gap ma&~ 1)~ the knife hladr with molten was. ll~t~ IY:LY 1~then thoroughly chilled.

0. Since the metal tr;l!. rlsetl had short flanges, it is iiecessar) to I~~~ilil the+flanges in \vxs to the reclriirrments of the intlividual case. The intli~~i~l~~all~~ Jmljared was flanges, after proper treatment. will not only confiiic tlie iiiilm.4oiimaterial without muscle triniining. hut will also ImGle sdficient sJI;~ ior 1~111~at1 d will facilitate rriiioval. The \\a;\; flanges make possible a clean ii-active oithe inlpression nlaterial iii estreme undercut :treas withont iitjur\.. In dtlitivli.the!. forin a niatris or I)ase \\-hich is extreliirl!~ helpful in ri.ssemhling the iracturetiJjieces. -1 solid nietal flange. in any sizalde uii(lercut, 5vc)uld injure 111~. issrlc.since it wodtl not Geld when the impression was renloved and \vc-~ultl vvry oftr :!destroy the iiilpression.

Remove the nufrriov :tlvedar guide form front the tray before zdaptitlg tlrc,\vas for the flanges. The retmaining posterior alveolar giiide forn34 :intt 11~.palatal guide form arc retained temporaril\- RS aids in seating the trax fI:ig. (3 IThe \vax for the flanges is prepared 1-1~softening the narrow end of n .5hrct ci-red refined wax. A f/ z inch strip is folded hack and united to J)rovitlc tu (1thicknesses of Leas. From this folded portion, ctlt two equal strip. I


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AN IMPRESSION PROCEDURE 655

alveoformtrimrbulk

The individual impression tray is completed as follows: The two remail ningliar guide forms are cut away from the metal base, leaving only a suffic ientmt ( f wax to confine and not to impinge tissues. Next, all of the palatal g uidewa x on the ridge area is removed. The tissue side of the wax flang e isned away up to the crest of its periphery or roll. This is to allow a suffic :ientof the impression medium, as explained previously. Sufficient exten sion

Fig. 8.-A and B, Creating the post dam


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mustthe tlthe 1%pillatrottilievecpress

helal;axis 1WI1 hwe


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\~olume 1Sumher 6

ironin tindiwillrapi

n the greater palatine foramina because these lie deep under the palatal glhe grooves in the palatine processes of the maxillae.An adept operator requires only ten or fifteen minutes to complete

vidual tray. If the steps have been properly executed, the individualmake it possible to take a balanced semistatic impression (Fig. 11). Aid-setting (forty-five to sevenths-five secondsi impression medium is used. 1-

Fig. 11 .-The comglered individual tray.

6.57ands

thetrayvery

-Iow-

Fig. U.-The maximum amount of impression material used and its location.


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ever, an accelerator may be added to the impression plaster used in t-he averagedental office for use in this technique. For all average patients, dcvuirl l.,t iooitflabby tissue, the material is mixed to a mlr crealu consistent>,. -I \x.m~!; cublicentimeters of room temperature water to 20 d\vt. of the rapid-setting ilnpressiciiimaterial is ltsetl. A thinner iliis is reconmientlrtl ior ljatients nith 101)5r flal11)itissue.

Fig. 13.-Insertion, with the impression material.Fig. 14.-Elevation of the lip and bilateral pressure.

7. The patient is directed to rinse the mouth with cold water while theoperator is mixing the impression material for 15 to 30 seconds. Only the hollowedout ridge portion of the tray is filled. The tray must not be overloaded (Fig. 12 ).


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Volume 1Surnher 6 AN IMPRESSION PROCEDURE 6.59The operator should stand behind the patient, elevate the lip to facilitate insertion,center and seat the tray against the maxilla (Fig. 13). With the maxilla ina horizontal position and the head of the patient firmly supported by the opera-tors body, an equal bilateral upward pressure of about 30 pounds is exertedwith the index fingers positioned on the center of the tray. Only after the trayhas been seated firmly in position should the lip be elevated with the thurnb toinsure an accurate impression of the labial portion of the maxilla (Fig. 14 ).

Fk. 15.

Fig. 16.Fig. %-The first step in the removal of the impression.Fig. 16.-Dropping of the finished impression.

The fast-setting impression material will not allow for muscle trimming, jugglingthe tray, or massage of the lip after the tray is seated. The steady equal pressureis maintained for about thirty seconds, then slowly released. After sixty toninety seconds, the impression may be removed.

8. To remove the impression, the operator should stand in front of thepatient. The thumbs are placed in the region of the maxillary fold just below


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the zygomatic process. The patient is instructed to claw. .lhe cherh~~ ;irr s.g-iihpw jfirmly between the index fingers and thunilrs 60 the l~ttccal tissues ui;i~. lw ix\tended upward, then iorwartl, \vhile the lnoutll is CIUAYI. This iiletliod will releabc.all impressions not coinplicatetl 1)~ rscrsbi\x, uiitleruits ( Figs. 15. ! C,, ;trul 17.i\ll fractured pieces are retrieved before the patient ririses the moutl~. I: ~~rlciu-c.nt~cause an impression to fracture, it shoultl Ix n~st~m~~letl t)eforv the. lxttltnt in.dismissed ( Figs. 18 and l(J I.

.A g-ootl working cast poured from thii type oi ati inipre~sion biilltll;tttb tluclosest approach to the actual condition of the tissues when the clultllrt. l):!h~.is in flinctioii. X denture base made over it \vill not exert uncluc* I)]-iiwrc ,113the alveolar ridge.

1 It is important to obtain and maintain a psychosomatic ecluilil)rium 4 lathoperator and patient.

2. Our clinical findings indicate that the lateral and anterior palatal ~~11:~(rugae area ) can be and are nsed as stress-hearing areas with very gratifyiiigresults.

3. Time is a very important factor in making impressiotl~, Tlw hest timeof the day to take an illl~~r~SskJll is after a pericK1 oi rest. No opeixtor c:ui maintainan equally balanced steady pressure for a long period of time. :\ vvry iast-settingimpression lllaterd Will kdell lwlg 1dOre there :lre my s&is CJf fatigue tothe tissues, patient, or operator. The short setting tilne (of the inlpression materialis of great value to the patient and the operator ii the patient happens tcb hr ;Lgagger. Time saved at the chair is ai1 vconoiiiic factor to the q,erator :tntlproduces less vexation t(J the patient. :\ proficient operator ca11 produce auacceptable impression in from fifteen to tn-enty minutes.


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AK IMPRESSION PROCEDURE

Fig. 18.

Fig. 19.Fig. lr?.-The completed impression.Fig. 19.-The completed imprcsxion showing the post (am elevation.

1. The most perfect impression, although a very important step, is onlyfourth in value to an acceptable denture precedure. The impression proceduredescribed is only a portion of a complete denture procedure known as thePsychosomatic Principles of Denture Practice.

64 WEST RANDOLPH STREETCI~JCAGO. ILL.

Documents

Balanced Semi Static