Inttmatianal Endodontic Journal (1985) 18,41-54

The relationship between periodontal and pulpal disease

p. H. A. GULDENER, Hehetiastrasse 9, Berne, Switzerland

Summary. The relationship hetween periodotitaldisease and pulpal disease is reviewed by first consi-dering their pathogenesis and differetitial diagnosis.The author then proposes a classification of lesionsbased mainly on their aetiolog}'; this is primaryendodontic lesion, primary periodontal lesion andcombined lesion. The treatment of the various typesis described in detail.

hand, endodontists fi-equentiy have a lack ofunderstanding concerning the treatment of thediseased periodontal tissues.

Therefore, it is important to correlate thesetwo entities, as confusion exists with regardto aetiology, diagnosis and therapy (Sinai &Soltanoff 1973).

Introduction

It Is well known that the dental pulp and theperiodontal tissues have a close interrelation-ship, both anatomically and functionally (Hiatt1959, 1964, 1977, Schilder 1963, Seltzer «ai .1963, Simon & Jacobs 1969, Seltzer 1971, Ross1972, Blair 1972, Cliacker 1974, Guldener1975, Simon 1980). The apical foramen is themost itnportant but by no means the onlylocation where these tissues meet. Lateral andaccessory canals, mainly in the apical area andin the furcation of molars, also connect thedetital pulp with the periodontal ligament. Inaddition, a great nuniiber of dentinal tubulesextend from the pulp to the cementum on tberoot surface. If the cementum is removed, e.g.scraped away by root planing, toxic substancescan be transmitted from the pulp to theperiodontal ligament or vice versa.

Many dentists consider endodontic andperiodontal lesions as separate entities. Obvi-ously, because periodontal disease and pulpalinfections are treated diflFerently, naany den-tists in the last 40 years have specializedin ]}eHodontics or endodontics. Combinedperiodontal-endodontic lesions require bothroot canal therapy and periodontal treatmentto save the tooth involvwl.

Pertodonttsts, being mainly concerned withtreating gin^val and periodontal disease,have little specialized knowledge about theproblems of the diseased pulp. On the other

Correspondence: P. H. A. Guldener, Helvetia-strasse 9, 3005 Berne, Switzerland.

Pathogenesis

The effect of periodontal lesions on pttlp tissueInvestigations on teeth in man and animals(rat, dog and monkey) have shown that thepulp may react in a variety of ways in the pres-ence of periodontal disease (Mazur & Massler1964, Seltzer et al. 1967, Bender & Seltzer1972, Langeland tfa/. 1974, Seltzer & Bender1975). The pulpal reaction may be infiuencednot only by the stage of periodontal disease,but also by the type of periodontal treatment,such as scaling, root planitig and admitiis-tratlon of medicaments (Stallard 1967). Thesize, number and location of accessory canals,the area of exposed root and the amount oftoxic substrates being transmitted into thepulp may also be important in the consequentseverity of puipal damage (Sinai & Soltanoff1973, Bergenholtz & Lindhe 1975). Pulpalchanges due n periodontal disease may occurin teeth with or without caries or restorations(Seltzer et al. 1%3). The predominant pulpalchanges due to toxic agents and medicamentswhich penetrate into the pulp via lateral catialsor dentinal tubules are degenerative in nature(secondary dentine formation, internal resorp-tion, fitHosis) (Rubach & Mitchdl 1965a).Inflammatory lesions of varying severity andnecrotic pulp tissue are usually found in teethwith large canats or in cases where theperiodonol breakdown has extended to theapex (Stahl 1966). In these inst^ces, apicalgranulomata, necrotic putp tissue in theapical region and enemal root resorpticHican be diagnosed (Simring & GtJdberg 1964,

4i

42 P. H. A. Guldener

Langeland et til. 1974). In about 40 per centof cases the pulp remains normal (Mandi1972).

The effect of pulpal lesions on periodontal tissueObviously, an infected or necrotic pulp maycause a periodontai lesion (Bergenholtz 1977,Sinai & Soltanoff" 1973). Endodontically-induced periodontal changes are referred to asperiradicular lesions (periapical, lateral, furca-tional). The periodontal response is alwaysinflammatory in nature, either acute (alveolarabscess, apical periodontitis) or chronic (granu-loma, cyst) (Stahl 1966). The lesion can. belocalized at the root apex or at the orifice ofa lateral canal within the periodontal ligament.

In addition, a sinus tract can develop whichmay extend from the apex to the furcation areaor even to the gingival sulcus. Such a sinustract must be distiogaished from a periodontalpocket. Endodontic treatment alone will causethe resolution of the sinus tract and healing ofthe damaged periodontal tissue.

Combined periodontal and endodontic lesionsFirst one has to distinguish separate periodon-tal and endodontic lesions which may occurindependently on a tooth from those endodon-tic and pedodontic lesions which join {Rubach& Mitchell 1965b, Simon & Jacobs 1969). Atthe latter stage both lesions are indistinguish-able froHi each other and it is not possible totell whether the primary lesion was endodonticor periodontal.

Diagnosis

Diagnosis of periodontal lesionsPeriodontitis is detected by clinical examin-ation (tissue colour and texture, pocket depth,bleeding tests), by radiographic interpretationand by histological findings. Tooth mobility isa frequent observation of moderate and ad-vaeced periodontitis, frequently in combinationwith occiusal trauma.

Diagnosis of endodontic lesionsClinically, the condition of the pulp can beclassified as a normal puip, reversible pulpitis,irreversible pulpitis or pulpal necrosis. Peri-apical lesions of pulpal origin can be clas.iiifiedas apical periodontitis, acute alveolar abscess.

granuloma, radicular cyst, and chronic alveolarabscess.

Acute pulpitis is detected by clinical signsand symptoms (pain), including thermal andelectrical pulp tests. Radiographs are importantfor the detection of caries.

Clinically, pulp degeneration is not an im-portant lesion under ordinary circumstances.Pain is generally absent when degeneration islimited to puipal tissue. Degenerative changessuch as reactionary dentine formation andintertia! resorption can be detected radio-graphically. However, hyalinization, atrophyand fibrosis are degenerative changes whichcannot be detected on radiographs since theyare radiolucent.

Histopathologically, the various stages ofacute and chronic pulpitis or degenerativechanges do not affect the treatment plan; in al!these situations pulpectomy is indicated.

Classification

The classification of teeth with pulpo-periodonrai changes suggested by the author isbased mainly on the aetiology of the disease(Guldener 1975, Hiatt 1977,""Simoo 1980).

Class I: primary endodsntic lesionClass l(al. Accidental perforations (intra-

alveolar) or resorptive perforations (internalresorption).

Class 1(B). Chronic periradicular lesion(granuloma or cyst) or acute periradicularlesion (alveolar absce.ss).

Class 11: primary periodatmJ lesionsClass n(A). Advanced periodontal disease

with or without extension to the apicai area{pulp vital).

Class 11(B). Secondary' endodontic involve-ment. Infection through lateral canals ordentinal tubules. Pulpal necrosis with or with-out secondary periapicai Involvement {pulpnon-vital).

Class HI: combined lesionTrue combined lesion (coalescence betweenperiodontal and endodontic lesion) or verticalcrown-root fracture with pulpal iavolvement.

Therapy

Treatment of a tooth with pulpo-perlodontalchanges should not he started before a defini-tive diagnosis has been established. Then, itmust he determined whether or not the toothinvolved can he sa%'ed. If the tooth or part ofa multirooted tooth can he saved, success mayhe influenced by the technique used and thesequence of therapy (Chacker 1974, Schilder& Grossman 1978)'

Therapy of primar)' endodontic lesions withinvolvement of the periodontal tissue andtherapy of primarj' periodontai lesions withsecondary pulp infection may be identical; thisis also true for the treatment of combinedlesions. Therefore, the following therapeuticprocedures will be discussed.

Root canal treatmentTreatment of accidental perforationsnon-surgicalsurgicalTreatment of resorptive perforationsIncision for drainagetndodontic apical surgerj*— periapical curettage— root resection (apicectomy)— apical fistulation

Rdatwmhip betmeen periodontai and pulpal disease 43

6. Diodontic implant7. Hemisection, tooth separation, root ampu-

tation8. Intentional replantation9. Extraction

/. Root cana! treatmentRoot canal treatment only in the presence ofperiradicular lesions is discussed here. Fre-quently, the lesion, if chronic, is located peria-pically and consists of a widened periodontailigament, a granuioma or a cyst. Less fre-quently, lateral or interradicular lesions onmultirooted teeth may also occur, when thepulpal inflammation extends through lateralcanals into the periodontai ligament space andcauses resorption of the adjacent bone. Perira-dicular lesions of endodontic origin are alwayscaused hy pulpal infection. Root canal treat-ment without surgerj- is indicated regardless ofthe size ofthe radiolucency (Fig. 1).

Schilder's 1962 study (Schilder & Grossman1978) in which 100 anterior teeth withperiapical radiolucencies (diameter 8-30 mm)were treated non-surgically, demonstratedcomplete bone regeneration in all cases but oneafter 2 vears. The treatment which failed was

Fig. 1. (a) l.iwcr first premolar with periapical radiolucency. (b) Two years after root canal treatmentof the alveolar hone mav be noted.

44 P. H. A. GuMener

•'1

Fig. 2. (a) Perforation in the middle third of the riiot ol J. (.cment t..n :H .icitUL-.l .uii.Kfi;- M ihc pcrlur-atioo (bi THo-and-a-hail~}ears after surfncal treatmcar o! the perlfirarion with silver amaR am. Nutc alsntht root canai liiiinK was redone.

on a maxillary lateral incisor with two roots,in which only one root canal had been filled.

2. Therapy of acciderMiperforationsAccidental perforations are treated surgicallyor non-surgically, depending on their size andlocation (Seltzer et al. 1970). They can beclassified into four groups:

Class 1: Cromi or root perforations coronal tothe epithelial attachment. If the perforationoccurs corona! to the gingiVal tissue, it isvisible and can easily be sealed from the out-side using composite resin. This is the onlyperforation which does not damage the perio-dontal tissue. If the perforation is located with-in a periodontal pocket, a small flap is raisedto allow the perforation to be treated in asimilar manner.

Class II: Perforations in the middle third of theroot. The treatment is either surgical or non-

surgical, depending on the size and location ofthe perforation. If the perforation was createdwith a root canal instrument, it is usualh"small. The perforation canal is then treatedlike an additional root canal. Care has to betaken not to overfill this artificial canal into theperiodoMa! ligatnent space. If, on the otherhand, the perforation is made with z bur duringpreparation for a post hole, the perforationshould he sealed from the outside with zinc-free silver amalgam (Fig. 2).

Class US: Perforations in the apical third of theroot. Class III perforations are the most fre-quent type, often due to the 'zipping effecfdescribed by Weine et al. (1976). In manyinstances, the perforation can be sealed con-servatively. If the perforated canal is slightlyoverfilled and the symptom-free periapicallesion heals uneventfully, no further treatmentis indicated. But, if clinical symptoms occuror an area can be detected radiographically,endodontic surgery is indicated (Fig. 3).

Relationship hetmem periodonlal and pulpa! disease 45

Fig. = . I • • Iapkt

ihe tooth was sensitive lo percussion, (b) Ten months after

Ciasi IV: Perforatiims in the interradicularspace of multirooted teeth. The rype of treatmentiodicated depends on the size of the perfor-ation and also on the health of the periodontaltissue. Perforations of small diameter aretreated non-surgically. The perforation may besealed with stiver atnalgam, gold foil or gutta-percha and root canal sealer. If, however, theperforation is large (> 2 mtn) root separationor hemisection is the treatment of choice.

i . Therapy of resorptive perforationsInternal resorptions that have perforatedinto the pedodonta! ligament space mtist bedistinguished from e.xternal resorptions thatperforate into the pulp.

Perforated internal resorptions can betreated non-surgically, but more frequentlyrequire surgical therapy. The conservativeapproach, suggested by Frank (1967), consistsof filling the entire root canal with calciumhydroxide, after the root canal systetn has beenthoroughly cleaned and shaped, to inducecememogenesis. .4fter 2—3 months, calcium

hydroxide is replaced by the definitive rootcanal filling: gutta-percha and sealer. Thesurgical treatment consists of reflecting a flapand sealing the perforation from the outsidewith silver amalgatn (Fig. 4).

External resorptions which are caused bypulp infection, in many instances can besuccessfully treated by root canal therapy.The resorptive lesion will cease to progress.External resorptions caused by trauma requiresurgical intervention (Fig. S).

4. Incision for drainageIn the presence of an acute alveolar ahscess,periodontal tissue is destroyed because ofpulpal infection. If the abscess has perforatedthrough the periosteum, there will be a fluc-tuaot STvelling of pus which can be displacedby palpation. To establish drainage, a sharpincision with a scalpel is tnade through thealveolar inucosa to bone. A drain (gauze stripor T-shape rubber dam) is placed into thewound to provide a channel for discharge ofpus and blood.

46 P. H. A. Guldener

"b

r

i

Fig. 4. (a) Internal resorption affecting 1/, labial perforation of the internal resorption cannot be seen onthe radiograph, (b) The defect was filled with silver amalgam, and an apicectomy was nho performed,(c) Radiograph several weeks after surgery.

Relationship helween periodontal and pulpal disease 47

Fig. $. (a) External lateral resuvpiioi: ,nid apit. I--hair the root was resected to eiiriiruitc iicsth ks.- •radiograph 2 | years after surgery.

itcly.',-up

Table I. The effect of the clinical condition on treatment

Treatment

Clinical condition

Canai blocked

Canal patentCanal underfilledCanal not Bcgotiatak

due to severe ciin-aturcApical perforation

Apical lesion whichdoes not heal

Canal which cannotbe dried

Canal overfilledwith symptoms

Svmpton:

AcuteChronic

AcuteAcute

ChroaicNone-Acute

Chronic

Chronic

Acute

Apical Root Periapical Retro- Root canaiSymptoms fistulation resection curettage filling treatment

_/ 4,! __/ ^

4- —Treatment indicated.—^=:Treatment not indicated.^The tooth mav l>e treated sureicaMv instead ofbv root canal treatmeot.

48 P. H. A. Guldmer

• •

< - • , • ••

I

Fi^;. 0. l;ii !loot canal filling with hot gutta-percha and vertical condensation (Schilder). Two lateral canalswert rilk-d near the apex; overextended root canal filling material is present within the periapica! lesion,(b) Periapical healing U years after periapical curettage.

5. Endodontic apical surgeryThis term, suggested by the author is moreprecise than the term '.A.picectoray'. Apicec-tomy is only one step in a procedtire which alsorequires periapical curettage and in many butnot al! itistances, a retrofilling. Sometimes,apical surgery is performed without apicec-tomy. Finally, the root is not always resectedat the tip. .Access in the molar and premolararea for placing a retrofilling is often onlygained if mid-root resection is performed;hence the term 'root resection' should besubstituted for the term 'apicectomv' (Table

I)-Endodontic apical surgerj' may be divided

into:(i) periapical curettage;

(ii) root resection with periapical curettage;and

(iii) apicai fistulation.

(i) Periapical curettage. PeriapicaS curertageis indicated mainly when root canal is over-filled, persistent pain exists and a root canalretreattnent is usually not feasible. A small flapis raised and surgical fenestration of the alveo-lar bone at the apex is performed. With a smallperiodontal curette, the excess root fillingmaterial and granulation tissue, if present, isremoved. In most instances, resection of theroot tip is not required (Fig. 6).

(ii) Root' resection. When root resection isdone, periapical curettage is always performedas well. The Indication for this common surgi-cal treatment is mainly limited to the followingsituations.1. Obstruction of the root canal (posts, broken

instruments, calcifications).2. Tortuous root canal that cannot be pre-

pared to the apex.

Relalionship iietwecn periodental and pulpal disease 49

Fig. 7. (a) Incomplete root cana! filling of 6 -. The t^o huccal canals contain silver cones, the palatal canala post and gutta-percha filling. Note the periapical lesion around the apices of the mesiobuccai and palatalroots, (h) Two years after apicectomy of both buccai roots. Goldfoil used as retrofilling. Palatailv. anapicectomy and periapicaJ corettage without retrograde fillmg was performed.

3. Canal that cannot be dried because ofcontinuous exudate.

4. Periapical lesion that does not heal despiteapparently correct root canal treatmenthaving been performed.

5. Apical perforation with symptoms.6. Apical external resorption.

In all cases in which the root canal cannothe negotiated to the apex (Figs 7 and 8) thesequence of treatment is as follows:1. Reflection of the flap.2. Location of the apex and surgical perfor-

ation of the alveolar bone.3. Root resection.4. Periapical curettage.5. Retrograde cavity preparation and retro-

grade filling, preferably with zinc-freesilver amalgam or a high-copper silveramalgam and varnish (Tronstad et al.1983).

6. Suturing of the flap.-'

If, however, the canal can be prepared to theapex, but cannot be dried, retrofilling is notrequired (Fig. 9). The sequence of treatmentin one visit is as follows:1. Reflection of the flap.2. Location of the apex and surgical perfor-

ation of the alveolar bone.3. Root resection.4. Periapical curettage.5. Drj'ing of the root canal.6. Root canal filling with overextension.7. Removal of excess filling material periapi-

cally.8. Suturing of the flap.

Endodontic apical surgerj' may be combinedwith periodontai surgery. In most instances,a full thickness flap is made at the gingiv'almargin, both on the lingual and buccal aspect.

(iii) .Apical fistulation. This is the surgicalcreation of a hole through the alveolar mucosa

50 P. H. A. Guldener

Fig. 8. (a) Perforatioa in the apical third of the mesial root of 6/ which has a periapical lesion, (b) Tenmonths after apicectomy and retrograde filling witli silver amalgam, the bony lesion has healed.

and cortical plate at the apex of a tooth withacute sy'Hiptoms to relieve pain. The techniqueis dangerous if it is performed without raisinga flap and first locating the apex. Anatomicallandmarks such as the maxillar}' sinus, themandibular canal or meotal nen'e in the neigh-bourhood of root apices of posterior teethshould be identified. In addition, apical fistula-tion is never a definitive treatment, but onlyfor emergency use in very rare cases. Theauthor does not recommend this procedure.

6. Diodentic implantsThis rather rare procedure is occasionally per-formed on a mobile lower anterior tooth withadvanced periodontal disease (Frank 1967).After normal preparation of the root canal, adrill is used through the root canal to createa space 6—8 mm into the alveolar bone. Dio-dontic implants function primarily by improv-ing the crown—root ratio, thereby stabilizingthe compromised tooth. Pocket elimination isperformed when necessary, and healing shouldbe complete prior to the implant procedure.Where the puip of the tooth is non-vital, theimplant should not be inserted at the first visitof endodontic treatment.

7. Hemisection, tooth separation and rootamputationThese techniques are performed on multi-rooted teeth, mainly on first and second molars

(Basaraba 1969, Abrams & Trachtenberg1974). These procedures are indicated ifperiodontal disease or caries prevent othersurgical intervention and the remaining rootor roots are needed for reconstruction of thedentition.

There are several pathological conditionswhich require one of these procedures.

(a) Periodontal.Advanced vertical bone loss around oneroot.Furcation involvement.Dehiscence extending to the apical third ofthe root.Close proximity of adjacent roots with miss-ing interdental septum.

(b) EndodonticObliterated canal with periapical lesionwhere surgerj- is not feasible.Large perforation in the furcation (ClassIV).Advanced external resorption of one root.

(c) Cronm—root fracture

(d) Extensive root caries of one rootBefore considering a hemisection or root

amputation, it is advantageous to performendodontic treatment of the remaining rootcanals first, otherwise the pulp will be exposedduring root resection.

Relationship hetrpeen periodontai and pulpal disease 51

i

v•>.' • k

Fig. 9. (a) Large penapical lesion and apical rooi lestirption of 3 . The root canal was treated for several\isit.s bul could niit be dned (b) '\pical curettagt was performed. After the root canal was dry. it wasintentionallj o\trfi!led with gutta-percha which was removed, (c) Radiograph 3 months after surgery,(d) Radiograph Hi months after surgery.

p. H. A. Guldmer

Fig. 10. (a) Periapicai lesion and radiolucency in the bifurcation of/S The mesial root canal is blockedby a post. Second and third molars are missing, (b) Hemisection was carried out. After removinc; the mesialroot, a four unit bridge was made using the distal root as an abutment.

/ ' - •

' • ' ^ -

Fig. 11. (a) Periodontally involved upper right first and second molars with furcation involvement, (b) Thedistal root of the second molar and the mesial root of the first molar were amputated, after endodontictreatment of the remaining roots.

Hemisection. This by defitiinon refers toseparation of a two rooted tooth (lower ttiokror upper first premolar) atid extraction of onehalf. The remaitiitig half is iotended as abridge abuttnetit (Fig. 10).

Tooth separation or bicuspidation. Toothseparation is the division of a two-rooted toothwithout extraction. Both halves are individu-ally crowned and appear as two premolars.

Root amputation. Root atnputation is theresection of one or two roots at the furcation(Smukler & Tagger 1976). Root amputation ismost often performed on maxillary molar teeth(Fig. 11). Root atnputation in the lower jawis rarely indicated and is confined to a molarwhich already acts as a bridge abutment.Amputation of one root should not jeopardizethe stability of the bridge. Root amputatedteeth should be crowned.

Relationship hetveen periodontal and pulpal disease 53

8, Intentional replantationIntentional replantation of a tooth is the lastresort when no other treatment is possible.This involves extraction of the affected tooth,apicectomy and retrofilling out of the mouthand finally replantation of the tooth in itssocket. The replanted tooth should bestabilized to the adjacent teeth for severalweeks. The prognosis of replanted teeth is notfavourable because more than one-third showroot resorption or ankyiosis after 5—10 years.Therefore, this procedure can only berecommended with great reservation,

9. ExtractionExtraction may be indicated, if treatment canbe simplified without loss of function andaesthetics. Teeth which are frequently sacri-ficed are those with advanced periodontaldisease or crown-root fractures.

Prognosis

The prognosis is generally better for a primaryendodontic lesion (Qass 1) than if pulpaiinfection was caused by advanced periodontaldisease.

If the lesion is solely endodontic in nature,the prognosis is excellent, whereas true perio-endo lesions (Class III) have a poor prognosis.In 1963, Schilder explained this phenomenonvery simply:

'The endodontist is working in a closed system.Once the rubber dam is placed and access isgained through the crown of the tooth to itsapex, the noxious protein breakdown products,tissue debris, bacteria and toxic products canbe eliminated and the eventually sterilized rootcanal may be filled. The periodontist has noneof these advantages. He is working in an opensystem. In the crevicular space, inflammationand reinfection, introduction of food particlesand bacteria are constant occurrences and thepermanent arrest of this type of disease is amonumental project.'

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