A Guide to the Endodontic Literature

 

 

 

Success & Failure:    

Authors

Description

 

 

European Soc. Endodontology (1994 IEJ):

Definition of Success: Clinical symptoms originating from an endodontically-induced apical periodontitis should neither persist nor develop after RCT and the contours of the PDL space around the root should radiographically be normal.

 

 

AAE Quality Assurance Guidelines

Objectives of NSRCT (= nonsurgical root canal treatment)

·          Prevent adverse signs or symptoms

·          Remove RC contents

·          Create radiographic appearance of well obturated RC system

·          Promote healing and repair of periradicular tissues

·          Prevent further breakdown of periradicular tissues

 

 

 

 

The Mantra:

·          Apical periodontitis (=AP; = periapical radiolucency =PARL) is caused primarily by bacteria in RC systems (Sundqvist 1976; Kakehashi 1965; Moller 1981)

·          If bacteria in canal systems are reduced to levels that are not detected by culturing, then high success rates are observed (Bystrom 1987; Sjogren 1997)

·          Best documented results for canal disinfection are chemomechanical debridement with Ca(OH)2 for at least 1week (Sjogren 1991)

·          Mechanical instrumentation alone (C&S) reduces bacteria by 100-1,000 fold.  But only 20-43% of cases show complete elimination (Bystrom 1981; Bystrom & Sundqvist 1985)

·          Do C&S and add 0.5% NaOCl produces complete disinfection in 40-60% of cases (Bystrom 1983)

·          Do C&S with 0.5% NaOCl and add one week Ca(OH)2: get complete disinfection in 90-100% of cases (Bystrom 1985; Sjogren 1991).

 

 

 

 

Problems with the Mantra

·          Koch’s postulates cannot be applied to establishing a bacterial origin of AP (since polymicrobial – Baumgartner)

·          Mantra misses host response contributions (eg; Stashenko’s P/E selectin knockout mice actually showed increased AP due to bacteria (thus, phagocytic leukocytes help to minimize AP via protection against microganisms; implies host defenses regulate the development of AP)

·          What is the clinical significance of a “non-cultivable” RC sample when organisms can reproduce in <12h?

·          Implication: the “mantra” is focused on what the clinician can accomplish with current methods (eg., reduction-disruption of a bacterial ecosystem).  It only provides general guidance for developing better therapeutic methods, and it cannot predict clinical success in cases where immunocompetence is altered.

·          Given a polymicrobial etiology and a disease-modifying host capacity, it is (probably) overly simplistic to correlate one bug with given signs or symptoms.  [Recall Sundqvist (1992) used odds ratio analysis & concluded that bacterial pairings in infected RC systems are not random, but appear to be due to forces such as ecological commensalism.  Since pairings can occur, correlational analysis between bugs and signs-symptoms may be confounded if one bug is more easily cultivable than another]

 

 

Penick, 1961

NSRCT with GP.  Still saw PARL at 14 months.  Sx biopsy revealed healing by scar (no inflammation). THL - consider healing by scar when reviewing post-endo tx (and sx work-ups)

 

 

Brynolf 1967

This study was performed on human cadavers with X-rays taken of 320 upper incisors.  Even though many radiographs appeared normal, complete histological healing after NSRCT occurred in only 7% of cases.  Thus, radiographic success doesn't correlate with histological success

 

 

Green, Walton,  1997

Compared radiographic findings of NSRCT to histological exam of human cadavers. 74% of the teeth with normal radiographic findings showed NO inflammation.   26% with a normal periapex radiographically showed histologic signs of inflammation. The results of this study do not agree with those by Brynolf in 1967 who found inflammation in the majority of the teeth that had received root canal treatment.

 

 

Ingle, Beveridge,

This study was done to evaluate treated endodontic cases and determine their rate of success.  33.41% of 3,678 patients returned for recall.  94.45% rate of success. The greatest cause of failure was interpreted to be obturation (but it may also be poor C&S).

 

 

Kerekes, Tronstad 1979

Examined 333 patients treated by undergraduate students.  Hand instrumentation with reamers and Hedstrom files was performed. EDTA and 5% chloramine-T was used for irrigation. Lat condensation with  gutta percha points coated with Kloroperka N-O.  Roots without periradicular radiolucencies prior to treatment showed better results than those with radiolucencies. No difference in success between vital and necrotic pulps, or in teeth with flare-ups during tx . Adequate seal and the apical level of the root filling were significant factors for the success of tx.

 

 

Bergenholtz 1974

Retrospective study of 84 teeth with trauma and intact crowns and necrotic pulps.  64% had microorganisms present (primarily polymicrobial anearobic).

 

 

Akerblom, Hasselgren 1988

Teeth with periapical radiolucencies had lower healing rates than those without a lesion. In teeth lacking lesions, 97.9% were judged successful. In the presence of a pre-operative lesion, only 62.5% teeth were deemed a success.   2-12 yr follow-up.

 

 

Ray & Trope , 1995

Radiographic exam of 1010 endodontically treated teeth restored with a permanent restoration.  The quality of the coronal restoration was significantly more important than the quality of the endodontic treatment for the presence of apical periodontitis.

 

Augsburger, Peters 1990

Radiographic evaluation of resorption of ZOE sealer/gutta-percha extruded into periradicular tissues. The rate of disappearance of the material did not differ with the presence or absence of radiolucent lesions, type of ZOE sealer used, or obturation technique. In no case did an irreversible lesion develop where sealer was expressed. Extruded material did not prevent radiographic repair of radiolucent lesions.

 

 

 

1-Step vs Multi-Step: Short-term Comparison

·          Pekruhn (1981): Compared postoperative pain after single-visit and multiple-visit NSRCT.  1 shot = multi-appt (both had 16% popln with pain at 1day)

·          Oliet  (1983): Compared 1 step to multi-appt NSRCT (n=380).  When pain occurred post-op, it typically presented within the first 24 hours; there was no difference between 1 shot vs  multi-appt, or for vital vs necrotic cases.  Also, no difference in healing at 18 months.  A difference in healing was observed when comparing the quality of the obturation in single visit treated teeth. Teeth that were overfilled showed less healing than those filled to or just short of the radiographic apex.

·          Roane, Dryden & Grimes  (1983): Compared 1 step to mult-step NSRCT (n=300). No differences in pain different anatomic groupings or pulp status (necrotic vs vital). Pain after 1-step was about one-half of pain after multi-appt NSRCT

·          Mulhern and Patterson (1982): 1 step NSRCTs does not increase post-op pain

·          Southard & Rooney (1984): The article strongly supports the position that 1-step NSRCT is an acceptable method to treat an abscessed tooth.  0 of 19 patients had exacerbations of swelling or pain following treatment. 63% of pts with AAA were contacted 24hrs post-NSRCT with IND, and all reported no or reduced pain.  Complete resolution of swelling resolved in 3-7 days. 58% of pts returned at 1 year and all were asymptomatic and showed radiographic signs of healing.

·          Eleazor & Eleazor (1998): Retrospective study: Flare-ups: 1 step (3%) < 2-step (8%; p<.01).  n=201 consecutive necrotic 1st & 2nd molars tx with 1-step had 3% flare-up vs n=201 consecutive necrotic 1st & 2nd molars tx with 2-visit (med= metacresylacetate) had 8% flare-up (p<.01)

 

 

Long-term Comparison

Oliet 83

Pekruhn 86

Trope 99

Freidman 95

Sjogren 97

1-Step vs Multi-Step: Long-term Comparison

·          Oliet  (1983): Compared 1 step to multi-appt NSRCT (n=380).  When pain occurred post-op, it typically presented within the first 24 hours; there was no difference between 1 shot vs  multi-appt, or for vital vs necrotic cases.  Also, no difference in healing at 18 months.  A difference in healing was observed when comparing the quality of the obturation in single visit treated teeth. Teeth that were overfilled showed less healing than those filled to or just short of the radiographic apex.

·          Pekruhn (1986): Evaluated failure with 1steps (n=925 @ 1 yr).  The overall failure rate was 5.2%. Most of the failures had preexisting apical periodontitis. 18% of these had symptoms. Retreatment cases had the highest rate of failure at 16.6%. The teeth tx with 1-step showed 3 times the failure rate as those previously opened for emergency treatment.  The higher failure rates of those teeth presenting with apical periodontitis may serve as contraindication for 1-step NSRCT.

·          Bystrom & Sundqvist (1981): One steps do not remove bacteria in necrotic cases.  Ca(OH)2 is the best inter-appt medicament to kill residual bacteria.  Simple mechanical debridement with saline is insufficient to remove all bacteria (although it does reduce bugs by 100-1,000 fold).

·          Sjogren (1997): Teeth with negative bacterial cultures prior to fill had 94% success rate whereas teeth with positive cultures had 68% success rate.  Also demonstrated that could not reliably obtain negative cultures after just one appt.  Others have also reported a simliar increase in prognosis when obturate canals with negative cultures: Engstrom (1964) and Oliet (1969).

·          Friedman & Trope (1995 JOE p386): n=378 eval Ketac-Endo for NSRCT.  Multi-appt NSRCTs with Ca(OH)2 medicament tended (86% vs 76%; p=NS) to have better success and fewer failures than one-shots.  6-18m follow-up

·          Trope & Orstavik (1999 JOE): Randomized clinical trial evaluating 1 step vs 2step with or without Ca(OH)2 with 1yr follow-up.  Ca(OH)2 had  74% healing > 1-step (64%; NS difference) > 2-step with no med (54% healing)

·          Katebzadeh & Trope (1999 JOE ): Dog study infected teeth with AP with 6m follow-up: C&S to size 45: 1week Ca(OH)2 med gave better PA healing after 6m than 1-step with LC Roths.  1-step was better than no NSRCT (= open canals = positive control)

·          Weiger, Axman-Krcmar & Lost (1998 EDT): One-steps tended (p=0.13) to produce poorer healing than multi-steps using Ca(OH)2 over 18 month period.  Used Cox regssion analysis of raw data from Lost et al (1995; n=76): analysis showed that that one-steps tended (p=0.13) to produce poorer healing than multi-steps using Ca(OH)2 over 18 month period

 

 

 

Studies justifying 1 year Recall:

·          Reit (1987): Best recall is at one year.  Also rec recalls annually for minimum of 4 years (esp in questionable cases)

·          Rud & Andreasen (1972): If PARL healed at 1 year, then ok

·          Orstavik (1996): ~76% of apical periodontitis lesions developing post-tx are seen within 1year.  Therefore, 1yr follow-up predicts long-term success

 

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Friedman 1998 Chap in Essential Endodontology by Pitt Ford & Orstavik

Meta-analysis of prior success-failure studies.   For NSRCT: Apical periodontitis success rate is 10-25% lower than NSRCT performed in teeth with normal periradicular tissue (=83-100%).  NSRCT Re-tx of teeth with AP = 56-84% healing.

Reviewed 27 studies (from Strindberg 1956 to Ostravik 1996): 78% of studies demonstrated >10% reduction in success.

 

 

Orstavik 1986

Proposed use of PAI (periapical index) to evaluate radiographic success by comparison to 5 standard images (healthy = 1; bad=2-5).

 

 

Davis & Joseph 1971

Classic! Teeth that were fully instrumented, but filled short of the radiographic apex had best healing.  ALSO: Seltzer & Bender 1963 &67 (human and monkey study with healing eval at 3 months; overfill = persistent inflammation)

 

 

 

 

Sjogren 1990

CRITICAL STUDY.  Necrotic teeth without AP have 96% success, but necrotic with AP have only 86% success.  Best success tx necrotic cases with apical periodontitis are when the obturation ends within 0-2 mm of radiographic apex = 94%); underfills are less successful (68% when filled > 2mm from apex) and overfills are less successful (76%).  Also, re-tx of teeth with AP have low success (62%).  Results are similar to Davis & Joseph (1971).

 

 

 

 

 

Causes for failure of NSRCT:  (see also: "Differential Dx of PARLs")

 

(If Dx is correct, bacterial infection is primary cause [Lin & Pascon (1991); Cheung (1996)].

 

·           “POOR PAST”  (Crump 1979)  P--perforation; O--obturation; O--overfill; R--root canal missed; P--periodontal disease; A--another tooth; S--split; T--trauma

 

·          Persistant Intraradicular infection (Nair 1990)

·          Sjogren (1997) reduced success when bacteria are present during obturation (94% vs 68%)

·          Pitt Ford (1982) infected dentinal tubules

·          Orstavik (1990): E. faecalis & Strep sanguis grew 300-400um into dentinal tublues after 14-21 days

·          Enterococcus faecalis in 33% failed NSRCTs (Molander 1998 IEJ) & in 60% failed cases reported by Siren (1997)

·          Actinomycosis israelii found in two case reports of failed NSRCT.  Had to be eliminated by Sx (Sundqvist 1981 OOO)

 

·          Persisitent Extraradicular infection,   see Simon's review on POP for general info and nice figs

·          Nair (1984) Actinomyces isrealii .  Also reported by Happonen (1986): 81% samples contained actinomyces, 62% contained arachnica

·          Sjogren (1988) Proprionibacterium proprionicum (aka Arachnia propionica)

·          Wayman (1992) evaluated 58 NSRCT failures in lesions with NO oral communication, 83% had bugs in lesion! (93% had bugs in      lesions with oral communication).  Similar to Iwu (1990) report of 88% lesions having cultivable bugs.

·          Kirye (1994): found infected cementum.  Also Tronstad (1990) reported bacterial plaque over apical foramen

·          Holland (1980): infected dentinal chips expressed into periapex.  Also reported by Yusuf (1982)

·          Foreign body reaction (Nair 1990).  Small particles of GP are extremely inflammatory [Sjogren (1995)]

·          Cysts, esp true cysts (Nair 1993, 1996).

 

 

 

 

Grung 1990

Success of re-tx combined with endo sx is 24% higher than endo sx alone

 

 

 

 

Specialist vs Generalist

As defined ONLY by radiographs, success of NSRCTs is 83-94% (Grahnen 1961; Ingle 1985) in clinical trials and 61-77% (de Cleen 1993; Erckerborn 1989) in epidemiologic studies.  The clinical trials represent optimal tx by specialists or well-supervised students, whereas the epidemiologic studies represent general practice.  (From Ericksen in Essential Endodontology 1998).

 

 

 

 

Lavstedt 1978

(in Norwegian) Teeth with greatest prevalence for apical periodontitis are max laterals, max 1st premolars and mand first molars..

 

 

 

 

Weiger, Axman-Kcmar and Lost EDT 14:1, 1998

Reviewed predictors of success of  NSRCT from statistical perspective.  Based on metanalysis, probability of PARL healing after NSRCT within 3yr is 0.87-0.89.  Used Cox regssion analysis of raw data from Lost et al (1995; n=76): analysis showed that one-steps tended (p=0.13) to produce poorer healing than multi-steps using Ca(OH)2

 

 

 

 

 

Studies showing reduced success of NSRCT with apical periodontitis:

                             Success (%):     No PARL         PARL       N 

1.  Molvern & Halse (1988)             91%               68%       207

2. Akerblom, Hasselgren (1988)      98%               62%         64

3. Sjogren (1990)                           96%               86%       471

4.  Friedman (1995)                        93%               69%       142

 

 

 

 

 

The NSRCT success rate for necrotic teeth vs vital appears equivocal

Smith (1993) reports reduced success with necrotic cases

Kerekes & Tronstad (1979) reports same success

Strindberg (1956) reports increased success with necrotic cases

 

 

 

 

 

Success of Re-Tx:

·          No PARL: 89-100%

·          PARL:    56-71%

Sources; Molvern & Halse 1988; Sjogren 1990 and Frideman 1995 (N = 569).

 

·          Bergenholtz (1979 Scan JDR): Classic on re-tx.  Group being re-tx for prosth indication (ie, not failing) still had 6% failure rate

·          Allen (1989 JOE): Classic: Retrospective study of 1,300 cases.  65% success 16% uncertain.  NSRCT Re-tx better success than sx (73% vs 57%). 

·          Sjogren (1990): re-tx teeth with AP has 62% success rate

·          Briggs & Scott (1997): Re-tx is preferable over endo sx (“evidence based” analysis). 

·          Moiseiwitsch & Trope (1998) Re-tx is preferable over endo sx

 

 

 

 

Success of Surgical Endo:

·          Apical Sx:              59%

·          Re-Tx + Apical Sx: 80%

·          Source: Friedman’s analysis in Essential Endo.  (nice initial meta-analysis approach).

 

·          Dorn & Gartner (1990 JOE): Retrospective study in two endo offices (non-randomized, etc): Success Super EBA 95%; IRM 91% and amalgam 75%

 

 

·          Rubenstein & Kim (1999 JOE): CRITICAL: Using scope, ultrasonics and Super EBA: n=94 cases (2/3 posterior & 1/3 anterior): 97% radiographic success at 3-12m follow-up with mean healing of 7.2m (criteria = restoration of lamina dura). 85% granuloma and 15% cysts with  no difference in time to heal.  Isthmuses were found in 25% of the cases.

 

·          Testori (OOO 1999): n=302 apices (181 teeth) with 5yr follow-up standardized radiographs with 2 observers: 85% complete healing with ultrasonic tips and super-EBA at 4.6yr versus 68% complete healing for rotary microhandpiece with amalgam.  Saw reduced success when had poor or no prior NSRCT (see Danin below)

 

 

·          Danin (1999 OOO): Did endo sx in necrotic cases without any NSRCT.  50% mod-complete success at 1yr (but used bur and glass ionomer for endo sx). But- 90% of these cases had cultivable bacteria in canals.  Important point: cases may show radiographic success after sx even with bacteria in canals.

·          Bradford (1999 OOO): defines sx success as 1) absence of symptoms; 2) absence of swelling, sinus tract, signs of infection; 3) radiographic evidence of healing; 4) continued normal functioning of the tooth.  Summarized qualities of an ideal root-end filling matieral: biocompatability, apical sealability and