Apical termination of root canal procedures—ambiguity or disambiguation?

22 Pages·2016·3.27 MB·English

by  James L. Gutmann

GutmannEvidence-BasedEndodontics (2016) 1:4 Evidence-Based Endodontics
DOI10.1186/s41121-016-0004-8
REVIEW Open Access
Apical termination of root canal
—
procedures ambiguity or disambiguation?
James L. Gutmann
Abstract
Theissuesofworkinglengthdetermination,itsapicalextent,andthepositionofthefinalrootcanalfillinghavebeen
controversial,asdifferingpointsofviewhaveexistedbetweenthebiologicallybasedandclinicallybasedendodontic
gurusregardingthisconceptfordecades.Coupledwiththefollowingissues,ithasbecomesomewhatofanempirical
bastion for clinicians, especially those in the limelight or who use social media to augment their clinical prowess:
(1) the variable anatomy of the root apex; (2) where to terminate canal enlarging and shaping apically; (3) status
of the accessory communications apically; (4) size of the apical preparation; (5) ability to debride the apical extent
of the root canal and remove both bacteria and biofilm; (6) response of the periapical tissues, when both vital
andnecrotic,totheintracanalfillingmaterialsandtechniquesthatmayimpingeonthesetissues;and(7)long-term
outcomesandassessmentsoftheproceduresrendered.Forpurposesofsuccinctness,theconceptofworkinglength,
theapicalpositionofinstrumenttermination,andthepositionofthefinalfillingwillbeaddressedsimultaneouslyin
thispaper.
Beyond the apex—danger lurks Review
Cravens JE. Immediate root filling. Trans Ill State Dent Codificationoftheprinciplesofrootcanalprocedures
Soc—29th Annual Meeting,The Dental Review Co., HD Up until the First World Conference on Endodontics
Justi &Son1893;45–59. was convened by Dr. Louis I. Grossman (Fig. 1) during
the week of June 22, 1953 (Grossman 1953), multiple
treatment parameters were being used daily by clinicians
Introduction and different philosophies of treatment were being es-
One could consider using a systematic review to try and poused in dental education around the world. Primarily,
answer the controversial challenges cited in the abstract; teeth were being extracted as opposed to addressing the
however, this approach would not work historically, and many challenges of root canal procedures due to the
from a contemporary standpoint, so very few, if any, overwhelming impact of the focal infection theory, along
published studies qualify to fit into the higher levels of with the apical anatomical challenges that had been
the hierarchy of scientific evidence that the essential is- highlightedinthe firstpartofthe 20thcentury.
sues would not be addressed (Gutmann & Solomon While not a recognized specialty of dentistry globally
2009). Therefore, a somewhat unorthodox approach to at that time, endodontics and the provision of root canal
this concept has been chosen,one in which historical re- procedures had been advocated routinely in some, very
flection and contemporary assessment will be used to limited, and visionary areas of dentistry, even with the
compare and contrast philosophies that address the is- name of endodontia being proposed by Dr. H. B. John-
sues of concern. The starting point will be the First ston and accepted by the community at large, including
International Endodontic Conference that occurred in the American Association of Endodontists (Gutmann
Philadelphia,PA,USA,in1953. 2008). However, this first world conference established
some significant guidelines for clinical procedures based
on historical documentation and treatment philosophy
up to that point, both clinical and biological. It is here
that this manuscript will begin to explore the issue of
Correspondence:[email protected]
working length in an attempt to clarify all aspects of the
TexasA&MUniversityBaylorCollegeofDentistry,Dallas,TX,USA
©2016TheAuthor(s).OpenAccessThisarticleisdistributedunderthetermsoftheCreativeCommonsAttribution4.0
InternationalLicense(http://creativecommons.org/licenses/by/4.0/),whichpermitsunrestricteduse,distribution,and
reproductioninanymedium,providedyougiveappropriatecredittotheoriginalauthor(s)andthesource,providealinkto
theCreativeCommonslicense,andindicateifchangesweremade.
GutmannEvidence-BasedEndodontics (2016) 1:4 Page2of22
that had been smoldering through various levels of con-
flagration since 1900 (Hunter 1900) but was brought to
a crescendo by William Hunter’s (Fig. 2) diatribe against
the dental profession during his classic presentation “An
Address on the Role of Sepsis and Antisepsis in Medi-
cine” that was delivered to the Faculty of Medicine of
McGill University in Montreal in 1910 and published in
1911 (Hunter 1911). Advanced further by Billings (Bil-
lings 1916) and Rosenow (Rosenow 1919), and perpetu-
ated by others at that time (Grieves 1914a; Grieves
1914b; Grieves 1920), this concept impacted greatly on
tooth retention. If tooth retention was deemed possible
in the presence of a questionable pulp or a tooth with a
periapical lesion, what treatment parameters may be
considered as both acceptable and successful? Therefore,
the issues addressed and the principles put forth from
this conference had to be carefully analyzed and bio-
logicallysound.To thatend,someofthefollowingques-
tionscould beasked retrospectively:
(cid:1) Historically,whatcontributed to thethinkingthat
helped tosolidifytheseprinciples?
Fig.1Dr.LouisGrossman—reproducedfromtheUniversityof (cid:1) Whatwasitaboutthebiology ofthe periapical
Pennsylvania1943.(http://www.aae.org/welcome/0207pulp.html)
tissuesand the clinicaltechniquesatthattimethat
ledtothisdefinitive position?
challenges involved in apical biology in relation to a pre-
ferredterminationpoint forrootcanalprocedures.
Whatweretheimportantoutcomesofthisfirst
conference?
While 21 principles of treatment parameters were forth-
coming, two very specific guidelines emanated from the
presentations and deliberations from a multitude of
international experts, in particular Drs. Louis I. Gross-
man, Lester B. Cahn, and Ralph Sommer from the USA,
Dr. Francisco Pucci from Uruguay, Dr. Birger Nygaard
Ostby from Norway, and Dr. George C. Hare from
Canada.Thesetwo principleswereasfollows:
1. Traumaticinjurytothe surrounding(periapical)soft
tissue shouldbeavoidedatalltimes. Tothisend,
instrument stopsshouldbeused and instruments
shouldbe confinedentirely within therootcanal
(Grossman1953).
2. “…the canal fillingshouldsealthe apicalforamen,
and thatiftheapicalmillimeterorso ofthe canal is
filled withhealthylivingtissue, therootcanalfilling
shouldterminateatthislevel ratherthan atthe
apicalforamen”(Grossman1953).
What was important at that time was the fact that Fig.2Dr.WilliamHunter—reproducedfromBremnerMDK.The
StoryofDentistry,DentalItemsofInterestPublishingCo.,NewYork,
dentistry and endodontics were still struggling with the
vestiges of the “focal infection theory” (Grossman 1925) 1939.AlsofoundinDentCosmos1934;76(1):19
GutmannEvidence-BasedEndodontics (2016) 1:4 Page3of22
(cid:1) Wasthisapproachtomanagingthe apical portionof It shouldbeborneinmind,thatat thepointwhere
theroot canal androot apextobethe sameinteeth the vesselsandnerves inquestion enter theroot,the
withviableapicaltissues ornecrotic apicaltissues passageismuchsmallerthatitisimmediatelywithin.
withor without theobviouspresenceofanapical Thisstrait (constriction) willbeeasily recognized
rarefaction? whenreached,bythetouch,the instrumentappearing
(cid:1) Wasthebestevidence availabletothe individuals in tobearrestedbyanobstacle, andnotbybeing
thisconference?Whatroledidapicalresorption wedgedinanarrow passage.Careshouldbetaken, I
playintheseguidelines,ifany? think,thattheinstrumentisnotallowedtopass
(cid:1) Whatwasknown abouttheroot apexin1953that throughthestrait,eitherbybeingtoosmall orby
wasnotknown in1911or before? beingrevolvedtheretillitcutsitsway through. For,
(cid:1) Whatwasknown abouttreatmentoutcomes in1953 bywoundingthepartswithoutthetooth,andforcing
relative tocurrent practicesatthattimeand particles of bone(dentin)out upon thepartsexternal
previouspracticesthatmay haveimpactedontooth totheroots,thedangerofanunfavorableresult
retention orsuccessfuloutcomes? would begreatly increased.(Harris 1855)
Subsequently, EdmundNoyes ofChicago notedthat:
Historicalgleanings
A sense of respect for the apical constriction in the roots …thetreatmentofpulps wasnot seriously undertaken
and the periapical tissues during root canal procedures bytheprofessionprevious to1865,andthatafter
already appears in the mid-1800s, when Dr. Harwood of 1870theattemptstosaveteethwith exposed living
Boston had communicated with Chapin Harris (Fig. 3), pulps,orwith deadpulps,becamequite common
oneoftheco-foundersofthefirstdentalschool,theBalti- practice,themethodgenerallyemployedbeingthe
moreCollegeofDentalSurgery,Baltimore,MD,USA,his removalofthe contentsofthe canalandplacing of
considerationsintheoperationsofcleaningtherootcanal from onetomanytreatmentsofcreosoteoncotton,
ofitspulptissue(Harris1855). mostoperatorsleavingsuchatreatment asaroot
filling.(Noyes 1922)
Little change in this philosophy existed until the late
1800s and the early 1900s, at which time the playing
field was identified as being far more challenging due to
studies on the root apex anatomy and apical root canal
that proliferated at that time (Fischer 1909; Preiswerk
1912; Hess 1917; Grove 1916; Noyes 1921) (Fig. 4). First,
recognizing the fact that there were significant apical
ramifications led dentists to performing many proce-
dures that only resulted in the removal of one half to
two thirds of the dental pulp (partial pulpectomy)
(Davis 1923);
Itisourpracticeat thistime toamputate largepulps
somewhere intheapicalthird oftheroot.With small
canals,asinthebuccalrootsofuppermolarsandthe
mesialrootsoflowermolars,we havebeen excising at
the floorofthe chamber…(Davis1923);
leaving challenges of the unpredictable apical anatomy
to normal healing processes; or focusing on the use of
substances such as arsenic to “sterilize” the retained ap-
ical pulp tissue and kill bacteria or tannic acid to form
an albuminate of tannin, which was insoluble and pre-
vented tissue disintegration (Mills1897):
Fig.3Dr. Chapin Harris—reproduced from Prinz H. Dental …wherewe cannot (reachthe apicalforamen), asin
Chronology,Lea&Febiger,Philadelphia,1945
contracted ortortuousrootcanals,weforce tannic
GutmannEvidence-BasedEndodontics (2016) 1:4 Page4of22
Fig.4aToothanatomydepictedbydyepenetration.FromtheworkofOskarKeller,AnatomiederWurzelkanäledesmenschlichenGebisses
nachdemAufhellungsverfahren.Zürich,Buchdruckerei,Berichthaus.1928.KellerwasaprotégéofbDr.WalterHess—reproducedbypermission
ofNicolaPerriniownerofthecollectionfromFondazioneCastagnolathatarefoundinStoriaanatomicadelsistemadeicanaliradicolari.Società
ItalianadiEndodonzia,2010
acidsolution into theinaccessiblepulp tissues…we
usedthetannicacidsolution because whenbrought
into contact with anyremainingpulp tissues inthe
rootcanal,itforms analbuminateoftannin; a
compoundwhich isinsoluble inany ofthe fluids of
the surroundingtissues,andconsequently no
disintegration cantake placetocause any after
trouble.(Mills1897)
The challenging nature of the apical root anatomy was
presented most vividly by Guido Fischer in 1907 (Fig. 5)
when he started his large-scale research, with a new
method in looking at human and animal root canals,
paying special attention to their thin ramifications and
apical terminations (Fischer 2010) (Fig. 6a–c). Fisher di-
vided the different morphologic variations of the pulpal
cavityinto:
(cid:1) Simpleramifications orbranchesand lateralcanals
withinthe radiculardentin
(cid:1) Intercommunicatingcanal system
(cid:1) Islandsof hardtissuewithin the canal
These differentiations were named as bifurcations and
ramifications, which created a complex system of apical
morphology. With his method, Fisher established the
accurate morphologic variations of a developing tooth,
either in physiological or pathological conditions. He de-
scribed very accurately the neoformation of dentin and Fig.5Dr.GuidoFischer—reproducedbypermissionofNicola
pulpstoneswithintherootcanals.Furthermore,byassoci- PerriniownerofthecollectionfromFondazioneCastagnolathatare
foundinStoriaanatomicadelsistemadeicanaliradicolari.Società
ating macroscopic and microscopic observations, he
ItalianadiEndotonzia,2010
showed how the root canal morphology is very complex
GutmannEvidence-BasedEndodontics (2016) 1:4 Page5of22
Fig.6ApicalramificationsasdescribedbyG.Fischer:asecondpremolar,bfirstmaxillarymolar,csecondmaxillarymolar.BauundEntwicklung
derMundhöhledesMenschenunterBerücksichtigungdervergleichendenAnatomiedesGebissesundmitEinschluβderspeziellenmikroskopischen
Technik.Leipzig;VerlagvonDr.WernerKlinhardt,1909
due to the ramifications present, calling them lateral ca- in this portion of the canal, dentin should be formed by
nals (Seitenkanal), and also apical ramifications called theodontoblastsinthepulp tissue.Ibelievethefact that
regioramificatoria,whichisreferredtopresentlyasanap- this does not occur clearly indicates the erroneous char-
ical delta. The complexity and inability to predict the acter of the theory that the pulp extends through the
canalmorphologybroughthimtonamethewholesystem foramen.” (Grove 1916). It is here that this author asks
astheradicularcanalsystem(Kanalsystem). oneofthemostcrucialquestionsthatthepresentmanu-
Subsequently, there began a true appreciation for the script is attempting to address: “The question now con-
nature of the tissue at the end of the root, as histological fronts us, What shall be done with these tissues when
studies were able to demonstrate that the pulp tissue thepulp isdevitalized?”(Grove1916)(Fig. 7).
ended at the dentinal-cemental junction and that there Key investigators, such as Noyes (Noyes 1922; Noyes
were few if any incidences of pulp tissue going all the 1921), Grieves (Grieves 1915; Grieves 1919), Blayney
way to the end of the root or to the extent of the major (Blayney 1927; Blayney 1922; Blayney 1926; Blayney 1940;
foraminal opening (Grove 1916; Noyes 1921). The issue Blayney 1932; Blayney 1936; Blayney 1929a; Blayney
nowwasthe clinicalmanagementofthese tissues. 1929b),Skillen(Skillen1922),Hatton(Hatton1922),Coo-
According to C.J. Grove, “It should be remembered lidge (Coolidge 1921; Coolidge 1922), Groves (Grove
that the apical foramen of fully developed teeth is 1921; Grove 1931),and Davis (Davis 1922a; Davis 1922b),
formed bythe cementum. Ifthe pulp tissue werepresent recognized these anatomical challenges, including that of
GutmannEvidence-BasedEndodontics (2016) 1:4 Page6of22
failure, while others had been in the mouth for a num-
ber of years (Blayney 1929b). Very early on in his study,
he realized that “it was unusual to find a root-end with
but a single apical foramen.” His conclusions strongly
suggestedthat:
“1)Thedentalpulpmayberemovedwithout causing
irreparabledamage totheperiapicaltissues,
providedthe followingdefiniteplanofoperationis
carriedout:a)surgicallycleantechnic ;b)useof
onlymildantiseptics,allcausticsbeingeliminated;c)
avoidanceofinjurytosofttissue inthe apical
foramina;d)removalofalltruepulp tissue;(and) e)
filling ofthe canal with abland,non-irritating,
non-absorbablefilling materialtonearthesiteof
amputation.
2) Followingtheoperation,thereisbegun,intheapical
region,aprocessofresorptionthatenlargesthe
apicalforamen,or anewchannelmay be cutthat
more successfullymeetsthe conditionswithin the
canal.
3) Theseresorptionsmay heal,with theformationof
calcifiedmaterialresemblingcementum.
4) Manyofthe apicalforaminamaybereduced insize
byrepair calcification.Butthisreductionseldom
obliteratesthe canal.assufficient spaceusually
remains foranefficientcirculatoryapparatus.
5) Thefilling material,when incontact withsoft
tissues,excitesaforeign-bodyreaction.Better results
Fig.7Histologicalviewoftherootapexwithrootcanalfilling
terminating2–3mmfromtheendoftheroot.Notethetissue areobtainedinthecasesthatareslightlyunderfilled.”
belowtherootfillingisperiodontalinnatureandthewallsofthe (Blayney1929b).
canalinthisareaarecoveredwithcementum.Thereisalsoahard
tissuebarrierthathasformedadjacenttotherootfillingthatmay
Similar findings were identified, and clinical tech-
havebeeninducedbydentinchipsorrepresentsanosteocemental
niques to achieve these results were supported by a
response.Thispresentationamplifiesthefactthatinmanyteeththe
pulpandpulpalcanalterminatesfarabovetheanatomicalrootend multitude of individuals during that era. As early as
1922, Noyes echoed these same directives as follows;
however, he was also concerned with root fillings that
cementalpermeability,especiallyinlightofthefocalinfec- were tooshort(NoyesE1922):
tion theory and still approached teeth with compromised
or necrotic pulps with the same focus, “Shall we, or shall Thereisone morethingIwant tosayinregard to
we not, attempt to retain the pulpless tooth? In the pres- thesefillings thatdonot reachtheends ofthe canal.
ence of the irrefutable dictum that the natural organ is Itismybeliefthatweshouldineverycase,wherever
betterthanany substitute, the answer is ‘Weshall.’ Noyes we canpossibly do so,getourfillingtotheendofthe
saidit succinctly; ‘…let us rathermakeita practiceto ex- PULP CANAL(Author’sEmphasis). Ineveryone of
tractonlysuchteethasdiligent,conscientiousandpersist- those casesinwhich Ididnot getthere,you may
ent effort have proven conclusively to be beyond our dependIspentanhour ormore,may two orthree,in
present ability to put in wholesome, safe condition.’” trying toget there.Butthe pointIwant tomake
(Noyes1921). particularly isthatwemay ignoreabsolutely the
In 1929, Blayney published his results on 10 years of foramenthroughcementum ifwe can fillthepulp
making histological analyses of root ends from extract canaltotheendofthedentin.Whileyou cannot filla
teeth that had been root treated. He had several thou- minuteforamen, which isasfineasahair insome
sand teeth in his history profile but chose to examine cases,inmyjudgmentatooth isthree orfourorten
histologically 250 of these teeth, some of which were ex- timesassafeifyou filltheroottotheendofthe pulp
tracted shortly after treatment due to a diagnosed canal,leavingthefine foramen throughthe cementum
GutmannEvidence-BasedEndodontics (2016) 1:4 Page7of22
oftherootwithoutmeddling with it,asitwould beif
you drilledthroughtheforamen andcarriedthefilling
totheendoftherootandput acape overtheendof
it, as Dr. Rhein advocates. (Fig. 8) (Author’s note:
Dr. Rhein advocated filling beyond the end of the
root so the filling material would encapsulate the
apical 2–3 mm, thereby sealing off all the accessory
communications.Hereferredtothisas“mortarization”
oftherootend.)(Fig.9)
However, Dr. Rhein had different opinions regarding
root canal therapy that stood in opposition to the main-
stream clinicians at that time, regarding procedural ac-
complishments(Rhein 1920):
Fig.9Maxillarymolarthathasrootfilingbeyondtheendofthe
Thequestionofroot-canaltherapy isone that rootthatencompassestheroot-endanatomy,asproposedbyRhein
embracesavery particular point,andthatis,thereis withhis“mortarization”
noquestion thatIknowof, asamedicalman,outside
of brain surgery, (andIwould even includealarge apicesoftheroots -Idefinitelyrefute the essential
amountof brainsurgery) thatrequiresthesame pointofcriticism oftheessayist’spaper. (Rhein 1920)
amountofskill,patienceandtime…When Ishow (Author’snote:thatrootcanalsshouldonlybefilled
hundredsofroentgenograms -some ofthem dating totheendofthedentinalcanalandnotimpingeon
backtoworkdonealmost30yearsago(Author’snote: the cementum).
whichwould beinthelate1890s),showingabsolutely,
sofarasaroentgenogram canshow,normaltissue To rationalize his technique of encapsulation even
(with)thoroughencapsulationofgutta percha onthe further,Dr.Rheinindicatedthat:
WhereIhavefound re-infectioninmyowncasesand
havehadtoextract teeth, Ihavealso found invariably
extraforaminaat somepointthathadnotbeen
encapsulated, andwhich were the cause ofthe
recurrenceofinfection.(Rhein 1920)
The issue of necrotic remnants being left in apical
accessory canals and treatment failure still reverberates
in today’s clinical practice and provides the impetus for
the promotion of filling to the root apex, using a tech-
nique in which these canals may be filled. However, this
achievement may be flawed with regard to histologically
identifiedoutcomes(Ricucci&Siqueira2010).
Interestingly, Grieves had fostered directives similar to
Blayneyasearly as 1914–1915relative to the importance
ofperiapicalpathosis,cemental repair,andapicalhealing
in the presence of the apical ramifications (Grieves
1914a; Grieves 1914b).
Thereissomeevidencefor believingthatremaining
vesselsandapical pulp-shreds,lyingintouch with
surrounding vascularity,eitherbecomeorganizedinto
fibroustissueorforaminaare closed bydepositsof
cementum orosteo-dentin.Thiscan occur onlyina
vital apex,notinfected, norsaturatedwith chemicals,
Fig.8Dr. Meyer L. Rhein—reproduced from J Dent Research norPERFORATEDANDOVER FILLED (Authors’
1933;13:100
Emphasis);andonly inone towhichthe
GutmannEvidence-BasedEndodontics (2016) 1:4 Page8of22
periodontiumisphysically attached.However,hegoes Therebedentistswhoconscientiously believethata
ontosay, inhis extensive treatise, “The vital apex is, pulplesstoothisadeadtooth; thatevery deadtoothis
thus,the cruxofallcanaloperations.Itsmaintenance doomedtoinfection; andthatallinfected teeth area
isworth anyamountoftime andeffort. Itcannotbe menacetothehealth oftheindividual. tosuch
encapsulated (Author’snote: asperDr.Rhein) practitionersthis communicationisnot addressed.
because periodontalfibers areeverywhereattachedto Therebeotherswho believethatapulplesstoothmay
it.Thereis,therefore,nodenudationorhypoplasiain besotreated thatitwillnot onlybetolerated bythe
whichencapsulationsmaylie,unlesstheytraumatically humanbody,but maybemadetoserveitsfunction of
protrudeintothemembrane,granulomata,orcysts. mastication,andaid intheinitialstepofdigestion,
Quite the reverse: the denuded apex, necrotic by thusbecominganimportantfactor inmetabolismand
whatever means, is not worth a moment’s effort, no anultimate contributortothe healthofthesubject.
matter how medicated nor how well filled (Author’s Fromsuch assubscribe tothese tenetsIcrave
note: this reflects the impact of focal infection). One attention,trustingthatImaydelivertothema
of the gravest mistakes of dentistry is the stubborn messagewhich mayinsomesmall degreerendertheir
belief that correct root-canal filling will cure apical effortstoministertosufferinghumanity more certain
disease.” (Author’s note: this same concept is present andmoreeffacious.(Ricucci&Siqueira2010)
today when clinicians say they are treating periapical
lesions or apical periodontitis) The most perfect To do so, Ottolengui dictated his doctrines for root
canaloperationisnevercurative,butonlyapreventive canalfillingprocedures(Ottolengui1922):
procedure.(Grieves1920)
“1.Anyradiographicevidenceofgutta percha beyond
Quite vocal in this controversy of where to terminate theapex oftheroot,is aprotrusionofthefilling
the root canal filling and the issue of retaining pulpless material…
teeth was Dr. Rodrigues Ottolengui (Fig. 10) of New 2. Theprotusionofguttaperchabeyond the apex
YorkCity(Ottolengui 1922): demandsspaceforitsoccupation.
3. …anyappearanceofgutta-perchabeyond theapex
ofahealthyroot isanevidence ofafault inthe
technique.
4. In the presence of infected apical areas…and the
gutta percha has been forced beyond the apex…
whether such infection, both of the area and of
the protruding foreign body can be overcome,
will be determined solely by the vital responses
of the patient in each instance. Sometimes a
cure will be accomplished in spite of the gutta
percha. It is inconceivable, however, that the
protruded material can act as a curative factor.”
(Ottolengui 1922)
Transitionsinthoughtandreaffirmationofclinical
directives
In the late 1930s, Dr. Bernhard Gottlieb (Fig. 11) pub-
lished a monograph entitled “Dentistry in Individual
Phases” (Gottlieb 1938). In this monograph, he dis-
cusses the challenges that are present in dealing with
root canal procedures, i.e., instruments and medica-
ments, thatmaycomeincontact withtheperiapicaltis-
sues during treatment. He indicated that he had no
concept as to the response of these tissues to the treat-
ment procedures, while at the same time hoping to
Fig.10Dr.RodriguezOttolengui—reproducedfromPrinzH.Dental control any inflammatory responses that may prevent
Chronology,Lea&Febiger,Philadelphia,1945.AlsofoundinDent
healing with calcified tissues. To these purposes, he
Cosmos1934;76(1):158
used a dog model in his investigations:
GutmannEvidence-BasedEndodontics (2016) 1:4 Page9of22
Gottlieb understood the challenges faced with human
teeth that required the removal of a viable dental pulp,
but he also realized the importance of this same set of
clinical circumstances in the presence of an infected
pulp ornecrotic pulp:
The claimsthatwe hadtosatisfy inthetreatmentofa
periapicalfocusofinfection tookanamuchmore
complicatedform, andaspectsdevelopedthatwe
could innowiseanticipate. We could formnoclear
pictureofwhat happened tothe necrotic root
surfaces,norcouldweimaginewhatmightbe
expected from branchings oftherootcanalsthat
harboureddeadtissue. Itwasdemonstrated that soon
after sterilizingandfreeingthesedeadtissue ofgerms,
the neighbouringinflamedconnectivetissueregained
health,andalmost atonce deposited cementum upon
the necrotic surfaces ofthe tooth.Thiscementum
may alsoclose uptheapical foramen, andthus
produceacomplete surface consistingofliving
cementum, which removescompletelyeverydoubt
concerning retentionofsuchatooth. (Gottlieb 1938)
In his assessment, Gottlieb defies the tenets of focal
infection, indicating that properly performed root canal
Fig.11Dr. Bernhard Gottlieb—reproduced from Gutmann JL. procedures, with retention of root-filling materials inside
Bernhard Gottlieb’s impact on contemporary endodontology. the canal in the presence of a necrotic pulp, will result
J Hist Dent 61:(2)85-106, 2013. Erratum 61:(3) 128, 2013. (http:// in biologic healing of the periapical tissues and the for-
www.alumni-meduniwien.at/news/medizin+im+bild/bernhard+
mation of a cementum closure of the canal apically
gottlieb). (http://www.alumni-meduniwien.at/news/medizin+im+
(Fig. 12). Furthermore, he was quite adamant about
bild/bernhard+gottlieb)
where to terminate these procedures, especially in the
presenceofavital,yetpossibly inflamed, pulp, indicating
that “surgical common sense forbids it” (that is, going
past the apical foramen). He indicated that there are
…inthe caseofextractionofthepulp itwasor healthy tissues at the point of severance apically, and
importancetoestablish,how any givenmethodwould therefore, the use of caustic drugs was prohibited, files
operatewhen thepulpcanalwasindirect connection must not penetrate the foramen (present day concept of
with theperiapicalconnectivetissue. In the case of patency filing), and any damage to the periapical tissues
the dog, on account of its ramifications the pulp may well prevent the healing of these tissues with the
tissue is without exception separated from the cementum (Davis 1923). He published his findings in
connective tissue, so that no connection is 1928 and presented them at the 8th International Dental
established with the periapical connective tissue Congress—FDI in 1931 in a special session that featured
throughout the manipulation in the canal. We world-class authorities who addressed the controlling of
now had to drill through the tooth to this area, rootcanaltreatmentprocedures (Gottlieb et al.1928):
and at once it was evident that we must use a
much more pretentious method, if we are to come Onceapieceofforeignmaterialhaspenetrated
in direct contact the periapical tissue and if we throughtheforamen, nofavorable condition ofany
were to care for injuries to the connective tissue. kindcaninducethe closureoftheentrancebythe
This change made in the procedure of the formation ofahardwall.(Gottliebetal.1950)
experiment by this drilling was necessitated by
the fact that in the human mouth it was not at Gottlieb’s philosophies went far beyond where to ter-
all uncommon to come in contact with the minate both instrumentation and obturation. Being one
periapical connective tissue during pulp extraction. of the stalwarts from the Vienna School of Medicine,
(Gottlieb 1938) who came to the USA (Gutmann 2013; Kremenak &
GutmannEvidence-BasedEndodontics (2016) 1:4 Page10of22
Fig.12Rootapexshowingcementalcoveragefollowingrootcanalproceduresandsubsequenthealing.Arepresentstherootfilling;Cisthe
originalcementum,whileDisthenewcementum;Bisthejunctionofthetwotissues;andEistheinflammation-freeperiodontalligament.
GottliebB.FromdataaccumulatedonProfessorGottliebfromtheGottliebCollectionpresentlylocatedattheBaylorCollegeofDentistry,Dallas,TX
Squier 1997), his focus in dentistry was highly biological that had been ground fine and sterilized. After mixing
and he devised a method to ensure the development of the dentin powder with sulfathiazole or restorative ce-
hard tissue (cementum) at the root apex following root ment, it was applied to the apical portion of the root
canal procedures. His method to achieve apical healing canal prior to obturation. The success of his approach
with cementum was simple. He used dentin from teeth was demonstrated in an animal model (Fig. 13) and
Fig.13Healingattherootapexwithcementumfollowingtheuseofadentin-cementrootcanalfillingintheapicalportionoftheroot.Gottlieb
B.FromdataaccumulatedonProfessorGottliebfromtheGottliebCollectionpresentlylocatedattheBaylorCollegeofDentistry,Dallas,TX