| Objective:Young permanent teeth are erupted but not fully developed teeth.In cases of tooth decays and dental injuries,the pulp of the young permanent teeth may be irreversibly infected and the development of the teeth may be arrested,leading to short roots,decreased thickness in the dentinal walls and open apices.Traditionally,several interventions such as apexification and apical barrier technique have been developed to achieve continued root formation.However,these traditional interventions still have several limitations and cannot provide ideal therapeutic effects.Over the last two decades,scholars have proposed the concept of pulp revascularization.After the root canal is thoroughly cleaned and sterilized,bleeding in the periapical tissues was induced using a hand file,resulting in the formation of blood clots inside the root canal.Up till now,,many cases of clinical trials have been published reporting successful outcomes of pulp revascularization.However,information regarding the success rate of pulp revascularization and the influencing factors is still unavailable from the existing literature.In this study,a systematic review,as well as a meta analysis,was conducted to evaluate the success rate of pulp revascularization and to explore the influencing factors.Materials and Methods:The electronic search was performed in the Pubmed,Scopus and Web of Science databases using the following keywords:#1:"regeneration" OR "revascularization" OR "maturogenesis";#2:"pulp necrosis" OR"pulp necroses" OR "infected teeth" OR "noise tooth";#3:"immature permanent teeth" OR "immature permanent tooth" OR "young permanent teeth" OR "young permanent tooth".Relevant studies published in English and Chinese reporting clinical trials of pulp revascularization of immature permanent teeth was retrieved from January 1,2001 to October 31,2017.The systemic review and the meta analysis were performed according to the guidelines of the PRISMA statement for meta-analyses and systematic reviews.Experiment I:Success rate of pulp revascularization performed in immature permanent teeth.Inclusion criteria:The study subjects were patients with necrotic young permanent teeth or irreversible pulpitis of young permanent teeth;the number of cases was not less than 10 and the follow-up period was not less than 6 months;the literature had complete raw data and analytic results.Exclusion criteria:literature not related to pulp revascularization;literature inconsistent with the procedure for pulp revascularization recommended by the American Association of Endodontists(AAE);reviews,meta-analyses and animal experiments;studies with fewer than 10 patients per study or a follow-up time of less than 6 months.Two investigators independently selected literature that met the inclusion and exclusion criteria,and extracted the following data:literature ID,author,and year of publication;age of the patients;sample size,number of successful cases,follow-up time;type and concentration of the irrigating agents;intracanal medicaments;the use of blood clots or biological scaffolds after induction of the periapical bleeding.Meta analysis was performed based on the extracted data using Statal4 Data Analysis and Statistical Software.The overall success rate of pulp revascularization in young permanent teeth was pooled across studies.Experiment II:Comparison of the success rate of blood clots versus biological scaffolds in pulp revascularization.Among the eligible studies included in Experiment I,comparative studies aimed at comparing the success rates of using blood clots versus biological scaffolds in performing pulp revascularization were selected The data were extracted exactly as described in Experiment I.Risk ratio(RR)was calculated using the STATA14 Software to compare the success rate in the Blood clot(BC)group with that in the Biological scaffold(BS)group.Results:Experiment I:Totally 26 articles with 573 cases were included in Experiment I.The potential risk of bias of these included studies was assessed using the methodological index for non-randomised studies(MINORS).All of the 26 included studies were scored 12 or above,and thus were all eligible for the following meta analysis.Quantification of heterogeneity indicated a moderate heterogeneity(I2=46.7%,p=0.005)among the studies,and therefore the random-effects model was selected to synthesize the data.Our results showed that the overall success rate of pulp revascularization in young permanent teeth was 91%,with the 95%confidence interval(CI)being 88%-94%.The sensitivity analysis revealed that the pooled success rate was stable after excluding each individual study.Meta-regression analysis was performed with the publication date,publication language or the patient age being included as covariates,respectively.Subgroup analysis was also performed with regard to the type of the intracanal medicament.However,none of these factors could explain the sources of heterogeneity among studies.Funnel plot,Egger's test and Begg's test all detected publication bias in the studies.Experiment ?:After screening,seven controlled studies were included in Experiment ?.A radom-effects model was selected based on a relatively high heterogeneity(I2=62.5%,p=0.020)among the studies.We found that the RR was 0.91(95%CI=0.76-1.08,p>0.05),comparing the success rate of the BC group with that of the BS group.No publication bias was detected by Egger's test and Begg's test.Conclusion:Experiment ?:Pulp revascularization performed on necrotic young permanent teeth has a high overall success rate,which provides a promising opportunity for the immature root to continue development.Furthermore,apexification and apex barrier techniques can still be performed after the failure of pulp revascularization.Experiment ?:In this study,no statistically significant difference was detected in the success rate of BC group when compared with the BS group.However,the sample sizes of the included studies were relatively small,which may,at least partly,account for the reason why no statistically significant difference can be detected.In order to obtain more accurate results,randomized comparative studies with larger sample sizes are strongly encouraged. |
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