the use of dental crowns for vital and endodontically ......the choice of dental restoration depends...

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TITLE: The Use of Dental Crowns for Vital and Endodontically Treated Teeth: A Review of the Clinical and Cost-Effectiveness and Guidelines

DATE: 05 February 2013 CONTEXT AND POLICY ISSUES The choice of dental restoration depends on the amount of remaining tooth, which may influence long term survival and cost.1 For endodontically treated teeth, it is believed that coronal coverage can improve the clinical success of the restored teeth.2 An endodontic post is a partial prosthesis that is fixed inside the root canal. They are used to retain the coronal restoration when considerable tooth structure is missing.3 A core is a built-up structure that compensates for the lost tooth structure. It can either be part of the post material or a different material that is attached or bonded to the intra-canal post. Composite restoration material is widely acceptable build-up material for this purpose.3 In the perspective of publicly funded health insurance plans, it is important to base the coverage of dental crowns for vital and non-vital teeth on the best available evidence. It is of particular interest these plans to define evidence-based criteria for the coverage of crowns for vital teeth, and for the coverage of using posts/cores and crowns on endodontically treated teeth. In Canada, such evaluation is complicated by the fact that publicly funded health insurance plans do not have control over the care provider’s choice of the crown type, and by the fact that there can be one fee code designated for all types of porcelain crowns, such as within the Ontario Ministry of Community and Social Services.4 The objective of this review is to evaluate the clinical and cost-effectiveness of dental crowns for vital teeth and the use of post-core-crown restorations for endodontically treated teeth. RESEARCH QUESTIONS 1. What is the clinical effectiveness of using dental crowns for vital teeth and dental

posts/cores and crowns for endodontically treated teeth? 2. What is the cost effectiveness of using dental crowns for vital teeth and dental posts/cores

and crowns for endodontically treated teeth?

The Use of Dental Crowns for Vital and Endodontically Treated Teeth 2

3. What are the evidence-based guidelines regarding the use of dental crowns for vital teeth? KEY FINDINGS The available evidence suggests that the short term survival (2 to 3 years) of crowns fabricated on vital teeth ranged from 87.9% to 97.7% depending on the materials used. The survival of post-core-crown restorations on endodontically treated teeth depended mainly of the amount of the remaining tooth structure. No clinical practice guidance or cost-effectiveness information was identified. METHODS Literature Search Strategy A limited literature search was conducted on key resources including PubMed, The Cochrane Library (2012, Issue 12), University of York Centre for Reviews and Dissemination (CRD) databases, Canadian and major international health technology agencies, as well as a focused Internet search. No filters were applied to limit the retrieval by study type. Where possible, retrieval was limited to the human population. The search was also limited to English language documents published between January 1, 2008 and January 10, 2013. Supplemental searches for guidelines and economic studies were conducted using PubMed and HEED. Methodological filters were applied to limit retrieval to economic studies and guidelines. Where possible, retrieval was limited to the human population. The supplemental search was also limited to English language documents published between January 1, 2002 and December 31, 2007. Grey literature (literature that is not commercially published) was identified by searching relevant sections of the Grey Matters checklist (http://www.cadth.ca/resources/grey-matters, sections C: Clinical Practice Guidelines and E: Health Economics), which includes the websites of regulatory agencies, health technology assessment agencies, clinical trial registries and professional associations. Selection Criteria and Methods One reviewer screened citations and selected studies. In the first level of screening, titles and abstracts were reviewed for relevance. Full texts of any relevant titles/abstracts were retrieved, and assessed for inclusion. The final article selection was based on the inclusion criteria presented in Table 1. Table 1: Selection Criteria

Population

Questions 1 and 2 Adults receiving crowns on vital teeth (teeth with intact nerve and pulp) and adults receiving crowns on endodontically treated teeth Question 3: Adults receiving crowns on vital teeth.

Intervention

Questions 1 and 2: Vital teeth: Dental single crowns (metalo-ceramic or porcelain fused to metal, all ceramic (and reinforced ceramic), and all porcelain (and reinforced porcelain). Endodontically treated teeth: Posts/Cores (pre-fabricated posts and metal posts) and dental single crowns Question 3: Dental single crowns

http://www.cadth.ca/resources/grey-matters


Comparator No comparator

Outcomes

Clinical benefit: longevity, and prognosis of the tooth and the dental crown Cost effectiveness (particularly in a public program setting where the incidence of caries is high) Guidelines and recommendations (for the use of crowns on vital teeth only)

Study Designs Health technology assessment, systematic review, meta-analysis, randomized controlled trials, economic evaluations, non-randomized studies, and guidelines

Exclusion Criteria Studies were excluded if they did not meet the selection criteria. Case reports, in vitro trials, and survey studies were excluded. Duplicate reports of the same outcomes from the same trials were also excluded. Additionally, primary studies were excluded if they were discussed in one of the included systematic reviews. Trials were excluded from this review if they were conducted on pediatric patients, teeth with fractured roots or scheduled for extraction, or if they were not clear if teeth were vital or endodontically treated. Exclusion was based on the trials intervention if the evaluation was for crowns used as abutments for removable/fixed prostheses, crowns fabricated on implant abutments, and for partial crowns and veneers. Trials on endodontically treated teeth were excluded if they evaluated casted posts and endo-crowns, and when the teeth were restored with posts with no crowns or with crowns with no posts. Critical Appraisal of Individual Studies Critical appraisal of the included studies was based on study design. The methodological quality of the included systematic reviews was evaluated using the “assessment of multiple systematic reviews” (AMSTAR).10 AMSTAR is an 11-item checklist that has been developed to ensure reliability and construct validity of systematic reviews. The included randomized controlled trials were evaluated using the SIGN50 checklist for the controlled studies.11 The observational study included in this review were evaluated using the SIGN50 checklist for the cohort studies.12 For the included studies a numeric score was not calculated. Instead, the strengths and limitations of the study were described. SUMMARY OF EVIDENCE Quantity of Research Available A total of 832 potential citations were identified by searching the bibliographic databases, with 793 citations being excluded during the title and abstract screening based on their irrelevance to the questions of interest.The grey literature search did not yield any relevant studies. The full text documents of the remaining 39 articles were retrieved. Of these, 32 did not meet the inclusion criteria and were excluded, leaving seven articles that reported on three systematic reviews,13-15 two randomized controlled trials,24,25 and two retrospective cohort studies.26,27


A PRISMA diagram demonstrating the study selection process is presented in APPENDIX 1. Summary of Study Characteristics Seven studies that addressed the clinical effectiveness research question were included in this review. The clinical efficacy of dental crowns on vital teeth was evaluated in one systematic review and one randomized controlled trial.13,24 The clinical efficacy of post-core-crown system in endodontically treated teeth was evaluated in two systematic reviews,14,15 one randomized controlled tial,25 and two retrospective cohort studies.26,27 Details regarding characteristics of the included studies are tabulated in APPENDIX 2. The search did not identify any relevant literature related to the cost-effectiveness of these interventions or clinical guideline for their use. Studies on the Clinical Effectiveness of Using Dental Crowns on Vital Teeth The systematic review by Ho et al.13 compared the clinical fracture resistance of CAD/CAM composite based crowns with CAD/CAM all-ceramic crowns. The searched period for relevant studies was not specified in the publication. Because of the specific interventions and outcome evaluated in this review, the review included one randomized controlled trial. The included study recruited 130 patients with a total 200 full coverage crowns. The primary outcome was crown survival. Enke et al.24 conducted a randomized controlled trial that examined the long-term outcome of all-ceramic crowns on posterior teeth compared with gold crowns. The trial recruited 222 patients who needed one full crown each. Inclusion of patients was not restricted based on the tooth vitality; however, results for vital teeth were given as a subgroup analysis. The main outcome of the trial was a composite cumulative incidence that included loss of vitality, fracture of the crown margin, partial crown fracture, full crown fracture, secondary caries and extraction of the abutment. Studies on the Clinical Effectiveness of Using Post-Core-Crown Restoration on Endodontically Treated Teeth The systematic review by Ng et al.14 evaluated clinical factors that may affect the survival of endodontically treated teeth. Of these factors, the review compared the effect of restoring the treated teeth with crowns versus no crowns, and it compared the effect of retaining the coronal restoration with a post versus no post. The review searched the literature published between 1993 and 2007, and it included 14 studies. The main outcome evaluated in this review was the survival ratio. In another systematic review Rasimick et al.15 studied the failure modes for post-core-crown restorations. The review included 15 studies that had a follow-up duration ranging from two to eleven years. Different post materials were evaluated including carbon, quartz, glass, ribbon and zirconium; however, the results were pooled without subgroup analyses for the specific materials. The review’s outcome was restoration failure rate. The randomized controlled trial by Bitter et al.25 evaluated the effect of using endodontic fiber post and the amount of residual coronal dentin on the time of failure of restorations of endodontically treated teeth. The trial included 90 patients and evaluated 120 crowned teeth; teeth were divided in subgroups based on the number of the remaining coronal walls. Full crown coverage was given for teeth that had no more than one wall remaining. The comparisons were


made between teeth that had an endodontic glass fiber post and teeth without the fiber post. For the “no-post group”, the core buildup was made with composite resin, and it was extended 3 mm in the root canals. The mean follow-up was 32 months, and the primary outcome was the loss of the restoration for any reason. Two retrospective cohort studies were conducted by Signore et al.26,27 The first cohort evaluated the clinical performance of an oval-shaped glass-fiber post used in endodontically treated premolars.26 The evaluation included 144 patients (164 premolar) which were followed for 45 months (mean duration). All teeth were restored with the fiber-glass post and all-ceramic crowns. Comparisons were based on the remaining number of coronal walls. In the second cohort,27 the survival rate of glass-fiber posts was evaluated. All teeth were restored with all-ceramic crowns. Comparisons were based on the shape of the post (parallel sided or tapered) and the type cement used (dual-cured composite or hybrid composite). The study included 200 patients (538 teeth) who were followed-up for up to 5 years. The main outcome in both studies was the restoration survival rate. Summary of Critical Appraisal The strength and limitations of included studies are summarized in APPENDIX 3. Studies on the Clinical Effectiveness of Using Dental Crowns on Vital Teeth: The systematic review by Ho et al.13 was based on scientifically sound method for conducting the systematic reviews. The review had an a priori defined protocol, two reviewers participated in the literature selection and data extraction, and the quality of the included trial was scrutinized in the review. According to the AMSTAR checklist,10 the review did not have limitations that could affect the reliability or the validity of conduct. For their randomized controlled trial,24 Encke et al. used an acceptable randomization method, and they provided a detailed protocol for tooth preparation. The sample size was one of the trial’s limitations; a convenient sample size was recruited in the trial rather than being based on power estimation. Another potential limitation of the trial was the fact that it was conducted in one academic facility; the skills and training offered in one facility might not be generalizable to other settings. Studies on the Clinical Effectiveness of Using Post-Core-Crown Restoration on Endodontically Treated Teeth: The systematic review by Ng et al.14 followed an a priori defined protocol and considered the quality of the included trials and their limitations in the interpretation of the review’s results. The results of the review should be interpreted with caution because the review conducted indirect comparisons between heterogeneous trials. Therefore, these comparisons should not be interpreted as conclusive. The methodology used by Rasimick et al.15 in their systematic review was not described. Furthermore, the review did not evaluate or consider the quality of the included studies. The randomized controlled trial by Bitter et al.25 followed an acceptable method of randomization and sample size calculation. The number of recruited patients was based on power calculation for a non-inferiority design. The non-inferiority margin of was 15% mean difference in failure rate between the post and no-post groups. However, the report did not


provide any explanation for the use of the 15% value. Another potential limitation of the trial was the fact that it was conducted in one academic facility; the skills and training offered in one facility might not be generalizable to other settings. The reports of the two retrospective cohorts by Signore et al. provided a detailed protocol for the tooth restoration procedure.26,27 Restoration and tooth evaluations were conducted clinically and radiologically by two independent investigators. A common potential limitation of the two studies was their generalizability; in the first study, all treatments were provide by one operator, and in the second one, treatment was conducted in a single academic facility. The treatment under evaluation is highly operator and technique sensitive; therefore, the generalizability of findings could be limited by the skills and training of the dentist who provided the treatment. Summary of Findings Studies on the Clinical Effectiveness of Using Dental Crowns on Vital Teeth: Ho et al.13 compared the success rate and the fracture-free survival of composite resin crowns and all-ceramic crowns after 3-year follow-up. The included study reported a success rate at 24 months of 65% for the composite crowns and 96% for the all-ceramic crowns. Crowns were considered successful if they had no anatomical changes, veneer chipping, seriously compromised esthetics, loosening, fracture or loss of integrity at margins. Because of this early failure of the composite crowns, allocation to this intervention was stopped, and patients were allocated to the all-ceramic group instead. With regard to the fracture-free survival, the study reported fracture rates of 6.8% and 4.9% and cumulative survival rates of 87.9% and 97.7% for the composite and all-ceramic crowns respectively. The difference between the two types of crowns was not statistically significant. The authors of the review concluded that there was insufficient evidence to make recommendation for the clinical use of CAD/CAM composite-based crown restorations. Encke et al.24 compared the cumulative incidence of failure between all-ceramic crowns and gold crowns. The cumulative survival at 24 months of follow up was 90.5% for all-ceramic crowns and 92.7% for the gold crowns; the statistical significance of the difference was not reported. For the vital teeth at baseline, there was numerically higher rate of loss of vitality during the study for teeth crowned with gold (8.9%) compared with the all-ceramic crowns (2.8%); the statistical significance of the difference was not reported. This result is interesting because it is expected that teeth with all-ceramic crowns will show more loss of vitality than teeth crowned with gold due to the greater amount of tooth reduction. The authors of this study couldn’t explain this phenomenon. Studies on the Clinical Effectiveness of Using Post-Core-Crown Restoration on Endodontically Treated Teeth: In a systematic review, Ng et al.14 evaluated the effect of using crowns and endodontic posts for restoration retention. They reported that the use of crowns on endodontically treated teeth was associated with increased survival rate when compared with non-crowned teeth; the odds ratio of survival was 3.9 (95% confidence interval [CI] 3.5 to 4.3). The use of posts did not significantly affect the survival of coronal restorations; odds ratio was 0.89 ((95% CI 0.75 to 1.05). However, these results should be interpreted with caution and should not be conclusive because of heterogeneity of the included studies designs. Furthermore, the review did not report


the condition of the evaluated teeth; for example, the number of the remaining tooth structures can affect the decision of using crowns and posts and affect the tooth survival as well. Rasimick et al.15 used information from 15 studies, with follow-up period of two to eleven years, to estimate the overall failure rate of the post-core-crown restorations for endodontically treated teeth; they reported an overall mean failure rate of 6.1%. The main reason of failure was post debonding (in eight studies) and endodontic lesions (in six studies). Bitter et al.25 evaluated the effect of using endodontic posts on the failure rate of the coronal restorations. After 3 years of follow-up, they reported an overall failure rate of 10% for teeth restored without posts as compared with 7% when the posts were used; the difference between groups was not statistically significant. The difference was statistically significant when the failure rate was evaluated in a subgroup whose teeth did not have any remaining coronal walls. For this subgroup, the use of endodontic posts was associated with statistically significantly lower failure rate (7%) when compared with the no-post group (31%). For teeth restored with metal-ceramic crowns, the group for which endodontic posts were used had numerically lower rate of failure (5%) as compared with the group without post (17%); the statistical significance of the difference was not reported. Signore et al.26 evaluated the effect of the remaining tooth structure on the cumulative survival rates of the fiber-reinforced post-core and crown restorations on endodontically treated premolars. The 32-month retrospective cohort data showed that the evaluated restorations had a statistically significantly higher survival when used for teeth with three or four coronal walls compared with teeth that had more structural damage. In another retrospective cohort of 5 years, Signore et al.27 showed that there was no difference in survival of the post-core-crown restorations when parallel-sided or tapered shaped posts were used. The survival rates ranged from 95.7% to 100%. Limitations A number of limitations exist in this review; There were insufficient studies that evaluated the long-term efficacy of dental crowns. In fact, the included studies that evaluated dental crowns on vital teeth had a follow-up duration of two to three years. With regards to studies on endodontically treated teeth, longer follow-up durations up to eleven years were found. However, these were mostly retrospective observational studies, and the evidence obtained from this type of studies cannot be considered as a source for conclusive evidence due to the high risk of patient selection bias and the difficulties in controlling confounding factors. The long-term evaluation of dental restorations is highly important for the publically funded health insurance plans because higher longevity of the restoration may justify the initial costs. Another limitation is that the included studies did not consider a high caries risk populations, and the risk of caries was not evaluated explicitly as an outcome in the include trials. Information about high caries risk populations and caries outcomes are crucial in the perspective of health insurance plans. The results obtained from studies conducted on the general public may not be generalizable to the patients insured with the public health plans; these patients are usually of higher risk of caries and may not have regular care provision and follow-up.


In Canada, there can be a unique fee code for all types of porcelain/ ceramic crowns, such as within the Ontario the Ministry of Community and Social Services.4 These types of crowns are available for the clinical use for more than three decades now, and each type of ceramic crowns has its specific clinical characteristics and physical proprieties. Unfortunately, direct comparisons to evaluate the clinical efficacy of each type or to compare between these crown types are lacking. Finally, to provide a comprehensive evaluation of the use of dental crowns, the current review was interested in the cost-effectiveness of their use and evidence-based practice guidelines. However, the searched literature search did not identify any relevant cost-effectiveness studies or evidence-based guidelines. CONCLUSIONS AND IMPLICATIONS FOR DECISION OR POLICY MAKING

This report compared evaluated the clinical efficacy of dental crowns used for vital teeth restoration and post-core-crown restorations for endodontically treated teeth. A total of seven studies or systematic reviews were retrieved. There was no relevant literature to answer the cost-effectiveness or clinical guidelines questions. With respect to the efficacy of vital teeth crowning, the data was limited to those obtained mainly from one randomized trial and a systematic review that included only one randomized trial. Both studies were of limited durations, two to three years. The available evidence suggests that the short term survival (2 to 3 years) of crowns fabricated on vital teeth depended on the materials used. There was no formal comparison between the different materials used in the fabrication of these crowns. With regards to the clinical efficacy of the use of post-core-crown restorations, the available evidence showed that the restoration survival depended on the remaining tooth structure; higher survival was observed with a higher number of remaining coronal walls. For teeth with one or no remaining walls, the use of post-core-crowns was associated with better survival than restorations without posts or crowns. PREPARED BY: Canadian Agency for Drugs and Technologies in Health Tel: 1-866-898-8439 www.cadth.ca

http://www.cadth.ca/


REFERENCES

1. Fedorowicz Z, Carter B, de Souza RF, Chaves CA, Nasser M, Sequeira-Byron P. Single crowns versus conventional fillings for the restoration of root filled teeth. Cochrane Database Syst Rev. 2012;5:CD009109.

2. Tikku AP, Chandra A, Bharti R. Are full cast crowns mandatory after endodontic treatment in posterior teeth? J Conserv Dent [Internet]. 2010 Oct [cited 2013 Feb 4];13(4):246-8. Available from: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3010030

3. Zarow M, Devoto W, Saracinelli M. Reconstruction of endodontically treated posterior teeth--with or without post? Guidelines for the dental practitioner. Eur J Esthet Dent. 2009;4(4):312-27.

4. Ministry of Community and Social Services. MCSS schedule of dental services and fees [Internet]. Toronto: MCSS; 2009 Apr. [cited 2013 Feb 4]. Available from: http://www.toronto.ca/health/dental/pdf/mcss_dentalschedule.pdf

5. Chadwick J, Gonzales A, McLean C, Naghavi A, Rosati S, Yau S. Restoration of endodontically treated teeth: an evidence-based literature review [Internet]. Toronto: University of Toronto, Faculty of Dentistry; 2008 Mar 20. [cited 2013 Jan 14]. Available from: http://www.utoronto.ca/dentistry/newsresources/evidence_based/EBReports08/Y1_EBL_Report.pdf

6. Cagidiaco MC, García-Godoy F, Vichi A, Grandini S, Goracci C, Ferrari M. Placement of fiber prefabricated or custom made posts affects the 3-year survival of endodontically treated premolars. Am J Dent. 2008 Jun;21(3):179-84.

7. Ferrari M, Vichi A, Fadda GM, Cagidiaco MC, Tay FR, Breschi L, et al. A randomized controlled trial of endodontically treated and restored premolars. J Dent Res. 2012 Jul;91(7 Suppl):72S-8S.

8. Mannocci F, Bertelli E, Sherriff M, Watson TF, Pitt Ford TR. Three-year clinical comparison of survival of endodontically treated teeth restored with either full cast coverage or with direct composite restoration. 2002. Int Endod J. 2009 May;42(5):401-5.

9. Vanoorbeek S, Vandamme K, Lijnen I, Naert I. Computer-aided designed/computer-assisted manufactured composite resin versus ceramic single-tooth restorations: a 3-year clinical study. Int J Prosthodont. 2010 May;23(3):223-30.

10. Shea BJ, Grimshaw JM, Wells GA, Boers M, Andersson N, Hamel C, et al. Development of AMSTAR: a measurement tool to assess the methodological quality of systematic reviews. BMC Med Res Methodol [Internet]. 2007 [cited 2013 Jan 10];7:10. Available from: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1810543/pdf/1471-2288-7-10.pdf

11. Scottish Intercollegiate Guidelines Network. Methodology checklist 2: randomized controlled trials [Internet]. In: SIGN 50: a guideline developer's handbook. Edinburgh: SIGN; 2008 [cited 2013 Jan 10]. Available from: http://www.sign.ac.uk/guidelines/fulltext/50/checklist2.html.

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3010030

http://www.toronto.ca/health/dental/pdf/mcss_dentalschedule.pdf

http://www.utoronto.ca/dentistry/newsresources/evidence_based/EBReports08/Y1_EBL_Report.pdf

http://www.utoronto.ca/dentistry/newsresources/evidence_based/EBReports08/Y1_EBL_Report.pdf

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1810543/pdf/1471-2288-7-10.pdf

http://www.sign.ac.uk/guidelines/fulltext/50/checklist2.html


12. Scottish Intercollegiate Guidelines Network. Methodology checklist 3: cohort studies [Internet]. In: Sign 50: a guideline developer's handbook. Edinburgh: SIGN; 2008 [cited 2013 Feb 4]. Available from: http://www.sign.ac.uk/guidelines/fulltext/50/checklist3.html.

13. Ho JCK, Hu YH, Montanera L, Shigapov T, Spano S. An evidence-based review of fracture resistance of CAD/CAM composite-based crowns [Internet]. Toronto: University of Toronto, Faculty of Dentistry; 2012 Apr 3. [cited 2013 Jan 14]. Available from: http://www.utoronto.ca/dentistry/newsresources/evidence_based/EBM2012/Group11_EBMReport2012.pdf

14. Ng YL, Mann V, Gulabivala K. Tooth survival following non-surgical root canal treatment: a systematic review of the literature. Int Endod J. 2010 Mar;43(3):171-89.

15. Rasimick BJ, Wan J, Musikant BL, Deutsch AS. A review of failure modes in teeth restored with adhesively luted endodontic dowels. J Prosthodont. 2010 Dec;19(8):639-46.

16. Wolleb K, Sailer I, Thoma A, Menghini G, Hammerle CH. Clinical and radiographic evaluation of patients receiving both tooth- and implant-supported prosthodontic treatment after 5 years of function. Int J Prosthodont. 2012 May;25(3):252-9.

17. Heintze SD, Rousson V. Fracture rates of IPS Empress all-ceramic crowns--a systematic review. Int J Prosthodont. 2010 Mar;23(2):129-33.

18. Beier US, Kapferer I, Dumfahrt H. Clinical long-term evaluation and failure characteristics of 1,335 all-ceramic restorations. Int J Prosthodont. 2012 Jan;25(1):70-8.

19. Kassem AS, Atta O, El-Mowafy O. Survival rates of porcelain molar crowns-an update. Int J Prosthodont. 2010 Jan;23(1):60-2.

20. Rinke S, Schäfer S, Roediger M. Complication rate of molar crowns: a practice-based clinical evaluation. Int J Comput Dent. 2011;14(3):203-18.

21. Rinke S, Schäfer S, Lange K, Gersdorff N, Roediger M. Practice-based clinical evaluation of metal-ceramic and zirconia molar crowns: 3-year results. J Oral Rehabil. 2012 Dec 5. Forthcoming.

22. Wang X, Fan D, Swain MV, Zhao K. A systematic review of all-ceramic crowns: clinical fracture rates in relation to restored tooth type. Int J Prosthodont. 2012 Sep;25(5):441-50.

23. Wittneben JG, Wright RF, Weber HP, Gallucci GO. A systematic review of the clinical performance of CAD/CAM single-tooth restorations. Int J Prosthodont. 2009 Sep;22(5):466-71.

24. Encke BS, Heydecke G, Wolkewitz M, Strub JR. Results of a prospective randomized controlled trial of posterior ZrSiO(4)-ceramic crowns. J Oral Rehabil. 2009 Mar;36(3):226-35.

http://www.sign.ac.uk/guidelines/fulltext/50/checklist3.html

http://www.utoronto.ca/dentistry/newsresources/evidence_based/EBM2012/Group11_EBMReport2012.pdf

http://www.utoronto.ca/dentistry/newsresources/evidence_based/EBM2012/Group11_EBMReport2012.pdf


25. Bitter K, Noetzel J, Stamm O, Vaudt J, Meyer-Lueckel H, Neumann K, et al. Randomized clinical trial comparing the effects of post placement on failure rate of postendodontic restorations: preliminary results of a mean period of 32 months. J Endod. 2009 Nov;35(11):1477-82.

26. Signore A, Kaitsas V, Ravera G, Angiero F, Benedicenti S. Clinical evaluation of an oval-shaped prefabricated glass fiber post in endodontically treated premolars presenting an oval root canal cross-section: a retrospective cohort study. Int J Prosthodont. 2011 May;24(3):255-63.

27. Signore A, Benedicenti S, Kaitsas V, Barone M, Angiero F, Ravera G. Long-term survival of endodontically treated, maxillary anterior teeth restored with either tapered or parallel-sided glass-fiber posts and full-ceramic crown coverage. J Dent. 2009 Feb;37(2):115-21.

28. Soares CJ, Valdivia AD, da Silva GR, Santana FR, Menezes Mde S. Longitudinal clinical evaluation of post systems: a literature review. Braz Dent J [Internet]. 2012 [cited 2013 Jan 14];23(2):135-740. Available from: http://www.scielo.br/pdf/bdj/v23n2/v23n02a08.pdf

29. Katsamakis S, Timmerman M, van der Velden U, de Cleen M, Van der Weijden F. Patterns of bone loss around teeth restored with endodontic posts. J Clin Periodontol. 2009 Nov;36(11):940-9.

30. Naumann M, Koelpin M, Beuer F, Meyer-Lueckel H. 10-year survival evaluation for glass-fiber-supported postendodontic restoration: a prospective observational clinical study. J Endod. 2012 Apr;38(4):432-5.

31. Gómez-Polo M, Llidó B, Rivero A, del Río J, Celemín A. A 10-year retrospective study of the survival rate of teeth restored with metal prefabricated posts versus cast metal posts and cores. J Dent. 2010 Nov;38(11):916-20.

32. Schmitter M, Hamadi K, Rammelsberg P. Survival of two post systems--five-year results of a randomized clinical trial. Quintessence Int. 2011 Nov;42(10):843-50.

33. Stavropoulou AF, Koidis PT. A systematic review of single crowns on endodontically treated teeth. J Dent. 2007 Oct;35(10):761-7.

34. Kim SG, Solomon C. Cost-effectiveness of endodontic molar retreatment compared with fixed partial dentures and single-tooth implant alternatives. J Endod. 2011 Mar;37(3):321-5.

35. Pennington MW, Vernazza CR, Shackley P, Armstrong NT, Whitworth JM, Steele JG. Evaluation of the cost-effectiveness of root canal treatment using conventional approaches versus replacement with an implant. Int Endod J. 2009 Oct;42(10):874-83.

36. Ng YL, Mann V, Gulabivala K. A prospective study of the factors affecting outcomes of non-surgical root canal treatment: part 2: tooth survival. Int Endod J. 2011 Jul;44(7):610-25.

http://www.scielo.br/pdf/bdj/v23n2/v23n02a08.pdf


37. Mancebo JC, Jiménez-Castellanos E, Cañadas D. Effect of tooth type and ferrule on the survival of pulpless teeth restored with fiber posts: a 3-year clinical study. Am J Dent. 2010 Dec;23(6):351-6.

38. Obradovich RN. Single-tooth restorations with a screw-retained, combined crown-and-abutment prosthesis. Pract Proced Aesthet Dent. 2008 Sep;20(8):465-72.

39. Ozkurt Z, Kayahan MB, Sunay H, Kazazoglu E, Bayirli G. The effect of the gap between the post restoration and the remaining root canal filling on the periradicular status in a Turkish subpopulation. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2010 Jul;110(1):131-5.

40. Sherfudhin H, Hobeich J, Carvalho CA, Aboushelib MN, Sadig W, Salameh Z. Effect of different ferrule designs on the fracture resistance and failure pattern of endodontically treated teeth restored with fiber posts and all-ceramic crowns. J Appl Oral Sci [Internet]. 2011 Jan [cited 2013 Jan 14];19(1):28-33. Available from: http://www.scielo.br/pdf/jaos/v19n1/07.pdf

41. Albino LG, Gradinar O, Rodrigues JA. Esthetic rehabilitation of anterior teeth with porcelain crowns reinforced with zirconia cores. Gen Dent. 2011 Jan;59(1):e1-e6.

42. Al-Omiri MK, Mahmoud AA, Rayyan MR, Abu-Hammad O. Fracture resistance of teeth restored with post-retained restorations: an overview. J Endod. 2010 Sep;36(9):1439-49.

43. Commentary by Francesco Mannocci and Tim Watson Mannocci F, Bertelli E, Sherriff M, Watson TF, Pitt Ford TR (2002) Three-year clinical comparison of survival of endodontically treated teeth restored with either full cast coverage or direct composite restoration. Journal of Prosthetic Dentistry 88, 297-301. Int Endod J. 2009 May;42(5):399-400.

44. Stankiewicz N, Wilson P. The ferrule effect. Dent Update. 2008 May;35(4):222-8.

45. Evidence-based review of clinical studies on restorative dentistry. J Endod. 2009 Aug;35(8):1111-5.

http://www.scielo.br/pdf/jaos/v19n1/07.pdf


APPENDIX 1: Selection of Included Studies

793 citations excluded

39 potentially relevant articles retrieved for scrutiny (full text, if

available)

32 reports excluded: -Duplicate publication or included in a systematic review (6)1,5-9 -Teeth vitality not specified (8)16-23 - The use of crowns was not specified (6)28-33 -Not intervention of interest (6)34-39 - Not study design of interest (6)40-45

7 reports included in review

832 citations identified from electronic literature search and

screened

0 potentially relevant reports retrieved from other sources (grey

literature)

39 potentially relevant reports


APPENDIX 2. Characteristics of the Included Studies

Characteristics of the Included Systematic Reviews

Review Objectives Types of Studies and Types of Participants Interventions and Comparators Outcomes

Ho et al. 201213

– Systematic Review – Vital Teeth/ Canada

Compare the clinical fracture resistance of CAD/CAM composite-based crowns with CAD/CAM all-ceramic crowns.

Type of Studies

o Literature search period was not defined o 1 study was included (published in 2010)

Prospective study The trial setting was not reported

Types of Participants

o Total of 130 patients – 200 full coverage crowns

o Stable occulsion o Age range from 18 to 70 years

All crowns were milled using the CAD/CAM technique

Intervention: (N=59 crowns)

o Composite crowns (GC Gradia)

Comparator: (N=141 all-ceramic crowns)

o All-ceramic crowns o 61 All-ceramic crowns were

placed during the randomized allocation of 1

st 120 crowns.

Primary outcomes:

o Crown survival at 3-months 1 year, and 3 year follow-up

Ng et al. 201014

– Systematic Review – Endodontically Treated Teeth/ UK

Investigate the effect of clinical factors affecting the survival of endodontically treated teeth.

Type of Studies

o Literature search period from 1993 to 2007 o 14 studies was included

9 Retrospective studies 5 prospective studies

o Follow-up ranged from 2 to 11 years


o Sample size varied from 50 teeth to 1,462, 936 teeth

The systematic review evaluated several clinical factors that might affect tooth survival after root canal treatment. Of interest:

Interventions/ Comparators:

o Restoring the teeth with crowns after root canal treatment (types of crowns were not specified) versus no crowns – n=4

o Retaining the restoration with post (type of coronal restoration not specified) versus no post retention – n=5

Primary outcomes:

o Survival ratio


Characteristics of the Included Systematic Reviews

Review Objectives Types of Studies and Types of Participants Interventions and Comparators Outcomes

Rasimick et al. 201015

– Systematic Review – Endodontically Treated Teeth/ USA

Determine the clinical failure modes for dowel/core/crown restorations luted with resin-based cements.

Type of Studies

o Literature search period was not defined o 15 studies were included (published

between 1998 and 2007 7 prospective studies 8 retrospective studies Follow-up varied from 2 to 11 years


o 3046 restorations (number of patients was not reported)

o Other patients characteristics were not reported

Teeth had to be treated with dowel (post), core and crown. Posts were luted with resin-based cements Dowel materials: Carbon (n=6), quartz

(n=3), glass (n=6), ribbon (n=1), and zirconium (n=1) Core materials: different composite

materials Crowns: PFM (n=13), all-ceramic

(n=7), all-porcelain (n=2)

Primary outcomes:

o Restoration failure rate


Characteristics of the Included Controlled Trials Study Objectives and Design

Inclusion Criteria, Sample Size, and Patient Characteristics

Intervention, Comparator, and Study Conduct Clinical Outcomes

Encke et al. 200924

– Randomized controlled trial – Vital Teeth/ Germany

Evaluation of the long-term outcome of all-ceramic crowns on posterior teeth as compared with gold crowns

Inclusion Criteria: patients with

Patients were recruited by public advertisement.

Patients were included if they needed full crown coverage on posterior teeth,

Teeth had to be vital of sufficiently treated for endodontics.

Sample size:

222 teeth / one crowned tooth per patients – mainly 1

st and 2

nd molars

Patients characteristics:

104 (47%) male and 118 (53%) female patients

Mena age was 42 years

Intervention: (All-ceramic crowns; N=123)

o Zirconium crowns (Everest HPC) o 71 (58%) vital teeth at baseline

Comparator: (Gold crowns; N=99)

o 67 (68%) vital teeth at baseline

Study Conduct:

Treatment was conducted in an academic facility

Study was conducted between 2004 and 2007

Patients were followed-up for 24 months

Primary outcome:

Cumulative incidence of the complications loss of vitality, fracture of the crown margin, partial crown fracture, full crown fracture, secondary caries and extraction of the abutment.

Bitter et al. 200925

– Randomized Controlled Trial – Endodontically Treated Teeth/ Germany

To evaluate the effect of using endodontic fiber post and the amount of residual coronal dentin on the time of failure of single-unit restorations RCT – blinding unclear

Inclusion Criteria:

patients in need of a postendodontic restoration

symptom-free tooth

root canal filling without periapical lesion and with a minimum apical seal of 4 mm

No active periodontal disease or furcation involvement > grade I

Sample size:

90 patients – 120 teeth; divided by the number of remaining walls

o 40 teeth had 2 walls o 40 teeth had 1 wall o 40 teeth had no walls exceeding

2 mm above gingival level

Treatment protocol

o Full crowns were chosen for teeth with a high coronal substance loss (N=75) 1 or no coronal wall remaining. Crown preparations were performed with a

circumferential ferrule of at least 2 mm

Intervention: (Post group)

o Glass fiber post (DT Light Post) 7–8 mm long apical seal ≥ 4 mm of the root canal filling.

o Post size (2 or 3) was chosen according to the root diameter.

o Post luting and core build-up were performed by composite material (Clearfil Core)

Comparator: (No post group)

Primary outcome:

Loss of the restoration for any reason. Secondary outcome:

Post debonding

Post fracture

Vertical or horizontal tooth fracture

Failure of the core portion requiring new coronal restoration

Endodontic or periapical lesion requiring endodontic retreatment

Tooth loss






42 men and 49 women, mean age 50 years

25 anterior teeth and 95 posterior teeth

o gutta-percha was removed from the root canals by using Gates Glidden burs to a depth of 3 mm from the canal orifice, and

o the core build-up was performed by using a composite material (Clearfil Core/New Bond)

o In cases of direct composite restorations, the build-up was performed by using composite material (Tetric Ceram/Syntac Classic).

Study Conduct:

patients recruited and treated in an academic facility

Four operators treated the patients

Study was conducted between 2004 and 2007

The mean follow-up period was 32 months

Signore et al. 201126

– Retrospective Cohort Study – Endodontically Treated Teeth/ Italy

Evaluate the clinical performance of an oval-shaped glass fiber post in endodontically treated premolars

Inclusion Criteria:

Patients needed restorations on endodontically treated maxillary and mandibular premolars.

Oval canal were selected only.

Minimum apical seal of 4 mm

Symptom-free teeth

The need for post and core to replace coronal tooth structure

Sample size:

144 patients – 164 premolar; divided by the number of remaining walls

o 19 teeth had 4 walls o 48 teeth had 3 walls o 49 teeth had 2 walls o 25 teeth had 1 wall o 13 teeth had no walls


63 men and 81 women, mean age 56 years

Treatment protocol

o Root canals preparation preserved at least 4 mm apical seal

o Fiber posts were cement with dual-curing composite resin cement. Same material was used for the core build-up.

o All teeth were crowned with all-ceramic full crowns (OPC 3G system)

Comparator:

o There were no compared interventions in this study.

o Comparisons were made between teeth based on the remaining tooth structure (number of walls)

Study Conduct:


One operator treated the patients

The follow-up period was 45 months

Primary outcome:

Restoration survival, defined as: o No root fracture, o No post fracture, o No post deponding o No failure of the core buildup o No crown replacement o No failure of the endodontic

treatment






– Retrospective Cohort study– Endodontically Treated Teeth / Italy

Evaluate the survival rate of glass-fiber posts with parallel-sided or tapered shape for the restoration of endodontically treated maxillary anterior teeth.

Inclusion Criteria:

Patients needed restorations on endodontically treated maxillary anterior teeth

Sample size:

200 patients – 538 teeth; divided by the number of remaining walls


79 (39.5%) men and 121 (60.5%) women

Treatment protocol

o Root canals preparation preserved at least 4 mm apical seal

o Fiber posts were cemented with either dual-cure or hybrid composite material

o Cores were build up as following: Teeth with 3 or 4 remaining coronal walls

the core was build up with dual-curing composite resin cement.

Teeth with 1 or 2 walls, the core was build up with hybrid composite material.

o A 2mm ferrule was prepared on the remaining tooth structure

o All teeth were crowned with all-ceramic full crowns (OPC 3G system)

Compared groups:

o Comparisons were based on the shape of posts and the type of cements used: Group A: parallel-sided post + dual-cured

composite cement (N=33) Group B: parallel-sided post + hybrid

composite cement (N=216) Group C: tapered post + dual-cured

composite cement (N=47) Group D: tapered post + hybrid composite

cement (N=230)

Study Conduct:


Four operators treated the patients

The mean follow-up period was up to 5 years

Primary outcome:

Restoration survival, defined as: o No root fracture, o No post fracture, o No post deponding o No failure of the core buildup


APPENDIX 3. Critical Appraisal of the Included Studies

Strengths Limitations

Ho et al. 201213


The review was based on a priori defined and reported protocol

Two reviewers participated in the literature search, selection, and data extraction

The quality of the included study was evaluated

No major methodological limitations

Ng et al. 201014


The review was based on a priori defined and reported protocol

Two reviewers participated in the literature search, selection, and data extraction

The quality of the included study was evaluated

Despite the design heterogeneity of the included studies, authors conducted indirect comparisons between the evaluated interventions. Results should not be interpreted as conclusive.



The characteristics of the included studies were described.

The review included a large number of teeth that had similar restoration after root canal treatment (carbon or glass core, composite core material and porcelain fused to metal crowns)

The review protocol was not described

It was not clear how the literature was selected

The quality of the included studies was not evaluated.

Encke et al. 200924


The trial used an acceptable randomization method

Teeth preparation followed a well-documented protocol

The trial included a convenient sample size rather than based on power estimation

Due to the nature of intervention, blinding was not feasible; however, the trial included hard outcomes which are unlikely to be affected by the unblended assessment.

The trial was conducted in one academic facility; the skills and training offered in one facility might not be generalizable to other settings.



The trial used an acceptable randomization method

The trial recruited a sample size based on power calculation. The calculation was based on non-inferiority design with a non-inferiority margin of 15% (mean difference in failure rate)

Tooth preparation followed a well-documented protocol

Radiographic assessment of teeth and restorations were done be a blinded investigator; however due to the nature of the intervention, blinding could not be achieved.


Although the trial was based on suitable method for the estimation of power and size of the sample; the value of the selected non-inferiority margin was not explained or supported by historical data.


Strengths Limitations



Tooth restoration procedure was well-document.

Two independent investigators evaluated the restored teeth clinically and radiographically

The treatment was conducted by one operator. The skills and training of a single dentist might not be generalized for other dentists.


– Retrospective Cohort study – Endodontically Treated Teeth/ Italy

Tooth restoration procedure was well-document.

Two independent investigators evaluated the restored teeth clinically and radiographically



APPENDIX 4. Main Study Findings and Authors’ Conclusions

Study Findings Authors’ Conclusions

Ho et al. 201213


Success rate at 24-month follow-up: (successful crowns had no anatomical changes, veneer chipping, seriously compromised esthetics, loosening, fracture or loss of integrity at margins)

64.7% for the composite resin crowns

95.6% for the all-ceramic crowns Due to the lower success rate for the composite crowns at 24 months, allocation to this group was stopped and all new crowns were fabricated with all-ceramic. Number of Fractured Crowns, n/N (%):

4/59 (6.8%) composite resin crowns

3/61 (4.9%) all-ceramic crowns Fracture-free survival (at the 3-year evaluation)

87.9% composite

97.72 ceramic

P-value of the difference in survival between the two materials=0.59

Authors concluded that there was insufficient evidence to make recommendation for the clinical use of CAD/CAM composite-based crowns as restorations.

Ng et al. 201014


Odd Ratio of Survival (follow-up period ranged between 2 and 11 years) Results should be interpreted with caution and cannot be considered to give definitive answers because of the limitation of data and heterogeneity of designs.

Comparisons No. of studies Odd ratio (95% CI) Heterogeneity test

Restoration with crown (yes versus no) 4 3.9 (3.5, 4.3) not significant

Restoration retained with post (yes versus no)

5 0.89 (0.75, 1.05) statistically significant



Failure rates of restorations (post-core-crown) on endodontically treated teeth (2 to 11 years follow-up)

Loss of retention is a major mode of failure for passive fiber dowel luted by bonded resin cements.

number of

studies Median (range) Mean

Overall failure rate 15 7% (0% to 29.6%) 6.1%

Failure due to dowel debonding 8 not reported 37%

Failure due to endodontic lesions 6 not reported 37%



Encke et al. 200924


Cumulative Incidence of Survival (failure defined as loss of vitality, fracture of the crown margin, partial crown fracture, full crown fracture, secondary caries and extraction of the abutment)

Results at 12-month evaluation indicated that zirconia crowns (EVERST HPC) were suitable for posterior full crown coverage. Reviewer’s comment:

Vital teeth did not show higher incidence of loss of vitality when compared to gold crown at 12 months.

All-ceramic (Zirconia crowns) N=123

Gold Crowns N=99

Hazard ratio (95% CI)

Cumulative incidence of survival (at 6 months)

98.3% 100% Not reported


95.9% 94.8% 1.79 (0.74, 4.32)


90.5% 92.7% Not reported

Loss of vitality (at the 12-month evaluation) 2/71 (2.8%) 6/67 (8.9%) Not provided



Failure Rates in the Evaluated Subgroups (Follow-up up to 3 years) Quartz fiber post placement was efficacious to reduce failures of post-endodontic restorations

Post insertion for teeth with minor substance loss should be critically reconsidered to avoid overuse.

Subgroup No post group Post group Difference

between groups

Metal-ceramic full crown; n/N (%) 6/35 (17%) 2/40 (5%) not provided

Metal full crown; n/N (% 0/3 0/2 not provided

All-ceramic full crown; n/N (% 0/6 1/8 (13%) not provided

Overall failure rate (after 3 years) (10%) (7%) 3% (-9.1%,

14.99%)

Failure rate – No-wall subgroup (N=40) 5 failures (31%) 1 failure (7%) P-value = 0.029

Failure rate – One-wall subgroup (N=40) 1 failure 2 failures p-value 0.353





The Comparative Cumulative Survival of Restorations Based on the Remaining Tooth Structure (mean follow-up of 32 months)

The fiber-reinforced oval posts had a satisfactory clinical performance

Survival was higher for teeth with three and four coronal walls.

The amount of tooth destruction was identified as a modifying variable that affect the survival of oval-shaped post and core buildup system

Cumulative Survival Rates, Number of events, n/N (%)

Statistical significance of the difference

No wall group versus 1 to 4 walls groups 3/13 (23%) versus 4/141

(3%) p-value = 0.0006

No wall group versus 1 wall group Not reported p-value = 0.4019

No wall group versus 2 walls group Not reported p-value = 0.0056



One wall group versus 2 walls group Not reported 0.0698



Two walls group versus 3 walls group Not reported 0.3223

Two walls group versus 4 walls group Not reported 0.5335


– Retrospective Cohort study– Endodontically Treated Teeth / Italy

Survival of the Post and Core restorations (mean follow-up 5.3 years) The long term survival of parallel and tapered glass-fiber posts was satisfactory when it was combined with either hybrid or dual-cure composite core buildups.

Compared groups Cumulative

survival Rate

Difference between Groups

Group A: parallel-sided post + dual-cured composite cement (N=33) 100% The Difference

was not Statistically Significant

Group B: parallel-sided post + hybrid composite cement (N=216) 98.2%

Group C: tapered post + dual-cured composite cement (N=47) 100%

Group D: tapered post + hybrid composite cement (N=230) 95.7%

the use of dental crowns for vital and endodontically ......the choice of dental restoration depends...

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