Influence of Coronal Restorations on the Periapical Health of ally Treated Teeth

Endod Dent Traumatol 2000; 16: 218–221 Copyright C Munksgaard 2000Printed in Denmark . All rights reserved

Endodontics &Dental Traumatology

ISSN 0109-2502

Influence of coronal restorationson the periapical health of endodonticallytreated teethTronstad L, Asbjørnsen K, Døving L, Pedersen I, Eriksen HM. L. Tronstad, K. Asbjørnsen, L. Døving,Influence of coronal restorations on the periapical health of I. Pedersen, H. M. Eriksenendodontically treated teeth. Endod Dent Traumatol 2000; Department of Endodontics, Faculty of Dentistry,

University of Oslo, Oslo, Norway16: 218–221. C Munksgaard, 2000.

Abstract – The purpose of the study was to evaluate a possiblerelationship between the quality of the coronal restoration, the rootcanal obturation and the periapical status of endodontically treatedteeth. Full mouth series of radiographs from randomly selectedpatient charts at the Dental Faculty, University of Oslo were exam-ined. A total of 1001 endodontically treated teeth restored with apermanent restoration were evaluated independently by two exam-iners. According to a predetermined set of radiographic criteria,the technical quality of the root filling of each tooth was scored aseither good (GE) or poor (PE), and the technical quality of the co-ronal restoration was scored as good (GR) or poor (PR). The rootand the surrounding structures were then evaluated and accord-ing to the periradicular findings, the treatment was categorized assuccess or failure. The success rate for all endodontically treatedteeth was 67.4% (nΩ1001). Teeth with root canal posts had a suc-cess rate of 70.7% (nΩ527) and teeth without posts had a successrate of 63.6% (nΩ472). The two groups with technically good endo-dontics had the highest success rates. In combination with technic-ally good restorations the success rate was 81% (GEπGR, 81%)and combined with technically poor restorations the success ratewas 71% (GEπPR, 71%). The two groups with technically poorendodontics combined with either good restorations or poor restora- Key words: apical periodontitis; dental treatment;tions had significantly lower success rates (PEπGR, 56% and endodontic treatment; periapical repairPEπPR, 57%). The technical quality of the endodontic treatment Leif Tronstad, Department of Endodontics,as judged radiographically was significantly more important than Faculty of Dentistry, University of Oslo,

P.O. Box 1109 Blindern, N-0317 Oslo, Norwaythe technical quality of the coronal restoration when the peri-apical status of endodontically treated teeth was evaluated. Accepted March 4, 2000

It is generally accepted that the prognosis of endodon-tic treatment is positively correlated with the technicalquality of the root filling (1–4). This appears logicalin that the root filling is meant to establish a bacteriatight seal of the root canal so that oral bacteria cannotreach the periapical tissues and cause disease. Thematerials that are available for the purpose of sealingthe root canal system are not without flaws, and anumber of studies using a variety of techniques have

218

suggested that even apparent adequate root fillingsmay not be effective over time (5–9). Thus, in one invitro study of coronal leakage of root filled teeth with-out coronal restorations, bacterial products werefound at the apex of the teeth after 3 weeks (10). Un-doubtedly a well-sealing coronal restoration is of im-portance to protect the root filling from the influenceof the oral environment. Ray & Trope (11) in a studyfrom 1995 have attempted to determine the relative

Coronal restorations and periapical health

Table 1. Success of endodontic treatment in a cross sectional study of dentalschool patients, University of Oslo

Success inn Failure Success percent

Entire material 1001 326 675 67.4%Teeth with posts 528 154 374 71.0%*Teeth without posts 473 172 301 64.0%*

* The difference between the success rate of teeth with root canal posts andteeth without posts was not statistically significant (PΩ0.025).

importance of the root filling and the coronal restora-tion in establishing and maintaining periapical healthin conjunction with endodontically treated teeth.Probably somewhat unexpected, in their materialthey found that the quality of the coronal restorationwas significantly more important for the long termsuccess of endodontic treatment than the quality ofthe root filling itself (11).

This study is important in that it directly involvesclinical therapy. At least to some extent the resultsundermine the fundamental understanding in endo-dontics that it is the root filling that creates the bac-teria tight seal and that the coronal restoration asmuch as possible protects the root filling and com-pletes the restoration of the tooth to function (12).Thus, it was felt that this question is importantenough that it should be looked at again. It was thepurpose of this investigation to duplicate the work byRay & Trope (11) as much as possible to again studythe relationship between the quality of the coronalrestoration, the root filling and periapical health ofendodontically treated teeth.

Material and methods

A cross-sectional study was performed by examiningfull mouth radiographs from randomly selected pa-tient charts at the Faculty of Dentistry, University ofOslo. The radiographs of the first 1001 endodont-ically treated teeth with a permanent restoration wereevaluated. Two independent observers examined theradiographs using a X-ray viewer with 2¿ magnifi-cation. Teeth with and without posts were examined.Multirooted teeth were categorized by the root withthe most incomplete rootfilling. The teeth weregrouped according to the radiographic qualities of theroot filling and the coronal restoration as follows:

Good endodontics: All canals obturated. No voidspresent. Root filling ending between 2 mm short ofand 1 mm beyond radiographic apex.

Poor endodontics: Root filling ending more than 2mm from radiographic apex. Root filling with voidsor canals not filled. Root filling poorly dimensionedor poorly condensed.

219

Good restoration: Any permanent restoration thatappeared intact radiographically.

Poor restoration: Any permanent restoration withradiographic signs of overhangs, recurrent decay oropen margins.

The radiographic appearance of the root and sur-rounding structures was then evaluated and categor-ized as follows:

Success: Normal width of periodontal ligamentspace. Normal appearance of surrounding bone.

Failure: Periradicular radiolucency.Three observers (KA, LD, IP) were calibrated ac-

cording to the system of Halse & Molven (13). Theevaluation criteria were discussed before initiation ofthe study. Forty-seven roots were used for calibrationin order to establish a uniform understanding and ap-plication of the criteria. One observer selected theroots and 2 observers examined the radiographs inde-pendently. Agreement was reached in 61,7%. Dis-agreement was dealt with by joint discussion. If con-sensus was not reached, the third observer made thefinal decision. After the study, 44 of the first roots thatwere examined were re-examined. Agreement wasreached in 79,5%. After joint discussion there was100% agreement.

Statistical analysis

Differences between the groups were examined statis-tically using the chi-square test. A P-value ,0.01 wasconsidered to indicate statistically significant differ-ences.

Results

The success rate for all endodontically treated teeth(nΩ1001) was 67.4%. Teeth with root canal posts (nΩ528) had a success rate of 71% and teeth withoutposts (nΩ473) had a success rate of 64%. The differ-ence between the groups with and without posts wasnot statistically significant (Table 1).

Table 2. Periradicular status of groups of teeth with good endodontic treat-ment, poor endodontic treatment, good coronal restorations and poor coronalrestorations

Endodontic Coronal Success intreatment restoration n Failure Success percent

GE Any 506 111 395 78%*PE Any 495 216 279 56%*Any GR 663 201 462 70%**Any PR 338 126 212 63%**

GEΩGood Endodontics; PEΩPoor Endodontics; GRΩGood Restoration; PRΩPoor Restoration; AnyΩAny Quality.* The difference between the success rate of teeth with Good and Poor

Endodontics was statistically significant (P,0.0001).** The difference between the success rate of teeth with Good and Poor

Restoration was stastistically significant (P,0.0001).

Tronstad et al.

Table 3. Success rate of endodontic treatment of good or poor quality in teethwith good or poor coronal restorations


GE GR 364 70 294 81%*GE PR 142 41 101 71%*PE GR 299 131 168 56%*PE PR 196 85 111 57%*

GEΩGood Endodontics; PEΩPoor Endodontics; GRΩGood Restoration; PRΩPoor Restoration.* The difference between the success rate with Good Endodontics and Poor

Endodontics was statistically significant (P,0.0001) regardless of the qual-ity of the coronal restoration (GR or PR).

Table 4. Periradicular status of the various groups of teeth with root canalposts





Table 5. Periradicular status of the various groups of teeth without root canalposts





The treatment was rated as Good Endodontics(GE) in 506 teeth. In this group the success rate was78%. The group with Poor Endodontics (PE) had asuccess rate of 56%. The difference between the 2groups was statistically significant (Table 2).

663 teeth were found to have Good Restorations(GR). The endodontic success rate in this group was70%. The group with Poor Restorations (PR) con-sisted of 338 teeth and the endodontic success rate inthis group was 63%. The difference between the 2groups was statistically significant (Table 2).

When the groups with Good Endodontics and

220

Good Restorations (GEπGR, nΩ364) were com-bined, the success rate was 81%. When the groupsGood Endodontics and Poor Restorations (GEπPR,nΩ142) were combined, the success rate was 71%.The difference between the 2 groups was statisticallysignificant (Table 3). The teeth with Poor Endodont-ics combined with the teeth with Good Restorations(PEπGR, nΩ299) gave a success rate of 56% whereasthe combination of Poor Endodontics and Poor Res-torations (PEπPR, nΩ196) resulted in a success rateof 57%. The difference between the success rate withGood Endodontics and Poor Endodontics was statisti-cally significant regardless of the quality of the co-ronal restoration.

The results of the combined groups in teeth withposts and without posts are shown in Tables 4 and 5.The presence of a post did not affect the endodonticsuccess rate negatively in any of the combinations.The lowest success rate (48%) was found in the com-bination Poor Endodontics and Poor Restorations(PEπPR) in teeth without posts (Table 5).

Discussion

The present study is a cross-sectional study based onevaluation of radiographs. Such a study has certainlimitations (13–16), but misinterpretations and misdi-agnoses are known to be fairly equally distributed sothat the results will be meaningful (17). Also, the re-liability of the present results was strengthened by thefact that a large material was studied.

The overall endodontic success rate was 67.4%.This was in good agreement with the results of otherstudies of this nature (11, 16, 18, 19). Of considerableclinical interest was the fact that the presence of rootcanal posts did not negatively affect the outcome ofthe endodontic treatment (20). Because of this, thegroups of teeth with posts and without posts weregrouped together in the study of the relationship be-tween the quality of the coronal restoration and theroot filling and periapical health.

Not unexpectedly the highest success rate (81%)was found in the teeth diagnosed with Good Endo-dontics and Good Restorations (GEπGR). In theteeth diagnosed with Good Endodontics and PoorRestorations (GEπPR) the success rate dropped 10%to 71%. This difference was statistically significant.Thus, the importance of a well sealing coronal res-toration for lasting success of endodontic treatmentthat was stressed by the findings of Ray & Trope (11)was evident in this study as well.

In the literature there is a consistant association be-tween periapical radiolucency and root canal fillingsof poor quality (for review, see 21). This was con-firmed by the present results. In the teeth diagnosedwith Poor Endodontics the success rate dropped andwas the same regardless of the quality of the coronal

Coronal restorations and periapical health

restoration (PEπGR, 56% and PEπPR, 57%). Thus,if the root canal was not properly obturated, the qual-ity of the coronal restoration had no bearing on theoutcome of the endodontic treatment. This findingwas in agreement with a recent study from Lithuania(22). However, it was in clear contrast to the findingsof Ray & Trope (11) who conclude that the quality ofthe coronal restoration is significantly more importantthan the quality of the root filling in securing peri-apical health.

The reasons for the discrepancies in the results ofthe two studies are not immediately clear. We tried toselect a material as similar to the American materialas we could (dental school patients, University of Osloversus dental school patients, Temple University).Certain differences in clinical technique migth exist,but since the evaluation criteria were very simple(Good Endodontics v. Poor Endodontics and GoodRestoration v. Poor Restoration) it is unclear whetherthis would have any bearing on the outcome of thestudies. In any case, the findings of this study wereclear. The quality of the root filling was the most im-portant factor for the outcome of endodontic treat-ment. If the quality of the root filling was good, agood restoration improved on the endodontic successrate. However, if the quality of the root filling waspoor, the quality of the coronal restoration was of noimportance for the outcome of the endodontic treat-ment.

References

1. Strindberg LZ. The dependence of the results of pulp therapyon certain factors. An analytical study based on radiographicand clinical follow up examinations. Acta Odont Scand1956;14(suppl. 21):1–175.

2. Bergenholz G, Malmcrona E, Milthon R. Endodontisk behan-dling og apikalstatus. II Röntgenologisk bedömning av rot-fyllningens kvalitet ställd i relation till förekomst av apikala de-struktioner. Tandläkartidningen 1973;65:269–79.

3. Kerekes K. Radiographic assessment of an endodontic treat-ment method. J Endod 1978;4:210–3.

4. Sjögren U, Hägglund G, Sundqvist G, Wing K. Factors affect-ing the long-term results of endodontic treatment. J Endod1990;16:498–504.

221

5. Tronstad L, Trope M, Doering A, Hasselgren G. Sealing abil-ity of dental amalgams as retrograde fillings in endodontictherapy. J Endod 1983;9:551–3.

6. Tronstad L, Barnett F, Flax M. Solubility and biocompatibilityof calcium hydroxide containing sealers. Endod DentTraumatol 1988;4:152–9.

7. Barnett F, Trope M, Rooney J, Tronstad L. In vivo sealingability of calcium hydroxide-containing root canal sealers. En-dod Dent Traumatol 1989;5:23–6.

8. Dickson S, Peters D. Leakage evaluation with and without vac-uum of two gutta-percha fill techniques. J Endod 1993;19:398–403.

9. Chailertvanitkul P, Saunders WP, Saunders EM, MackenzieD. An evaluation of microbial coronal leakage in a restoredpulp chamber of root-canal treated multirooted teeth. Int En-dod J 1997;30:318–22.

10. Torabinejad M, Ung B, Kettering JD. In vitro bacterial penetra-tion of coronally unsealed endodontically treated teeth. J En-dod 1990;16:566–9.

11. Ray HA, Trope M. Peripical status of endodontically treatedteeth in relation to the technical quality of the rootfilling andthe coronal restoration. Int Endod J 1995;28:12–8.

12. Tronstad L. Clinical endodontics. A textbook. New York: Thi-eme; 1991.

13. Halse A, Molven O. A strategy for the diagnosis of periapicalpathosis. J Endod 1986;12:534–8.

14. Eckerbom M, Magnusson T. Evaluation of technical quality ofendodontic treatment – reliabilty of intraoral radiographs. En-dod Dent Traumatol 1997;13:259–64.

15. Eriksen HM. Endodontology – epidemiologic considerations.Endod Dent Traumatol 1991;7:189–95.

16. Eriksen HM, Bjertness E, Ørstavik D. Prevalence and qualityof endodontic treatment in an urban adult population in Nor-way. Endod Dent Tramatol 1988;4:122–6.

17. Altman DG. Practical statistics for medical research. 1st ed.London: Chapman & Hall; 1991. p. 99–101.

18. Petersson K, Petersson A, Olsson B, Håkansson J, WennbergA. Technical quality of root fillings in an adult Swedish popula-tion. Endod Dent Traumatol 1986;2:99–102.

19. Eckerbom M, Andersson J-E, Magnusson T. Frequency andtechnical standard of endodontic treatment in a Swedish popu-lation. Endod Dent Traumatol 1987;3:245–8.

20. Kvist T, Rydin E, Reit C. The relative frequency of periapicallesions in teeth with root canal retained posts. J Endod1989;15:578–80.

21. Friedman S. Treatment outcome and prognosis of endodontictherapy. In: Ørstavik D, Pitt Ford TR, editors. Essential Endo-dontology. London: Blackwell; 1998. p. 373.

22. Sidaravicius B, Aleksejuniene J, Eriksen HM. Endodontictreatment and prevalence of apical periodontitis in an adultpopulation of Vilnius, Lithuania. Endod Dent Traumatol1999;15:210–5.

Influence of Coronal Restorations on the Periapical Health of ally Treated Teeth

Documents

Transcript of Influence of Coronal Restorations on the Periapical Health of ally Treated Teeth