METHODS: Electronic searches were performed in Web of Science, PubMed, CINAHL (Cumulative Index to Nursing and Allied Health Literature), and Cochrane Library databases. Two authors independently screened the titles and abstracts for eligibility. The analyses were performed on the clinical outcomes (ie, survival, healing, and root development) of the procedure.
RESULTS: Eleven articles were included in the qualitative and quantitative syntheses. Three studies were randomized controlled trials, 6 were prospective cohort studies, and 2 were retrospective cohort studies. The pooled survival and healing rates were 97.3% and 93.0%, respectively. The pooled rates of root lengthening, root thickening, and apical closure were 77.3%, 90.6%, and 79.1%, respectively. However, if 20% radiographic changes were used as a cutoff point, there were only 16.1% root lengthening and 39.8% root thickening.
CONCLUSIONS: Within the limitations of the present study, it can be concluded that RET yielded high survival and healing rates with a good root development rate. However, clinical meaningful root development after RET was unpredictable.
METHODS: The specific PIO questions were as follows: Population: Patients with periapical periodontitis either before or after non-surgical endodontic therapy.
INTERVENTION: IR performed with retrograde preparation and retrograde filling.
OUTCOMES: the healing, treatment complications, and the factors influencing these outcomes after IR. Electronic and hand searches were performed in the Web of Science, PubMed, CINAHL, and Cochrane Library databases. Two authors independently screened the titles and abstracts for eligibility. The risk of bias was performed using the NIH Quality Assessment Tool, and each study was rated as "Good", "Fair" or "Poor". The analyses were performed on the treatment outcome (healing and complications), and the factors influencing the outcome of the procedure.
RESULTS: Fourteen articles were included in the qualitative and quantitative syntheses. One was a prospective cohort study, and the other 13 were retrospective cohort studies. Overall, the evidence of this review was of poor-to-fair quality. The pooled healing rate was 80.2%, and there was a 21.7% of complication rate. Longer follow-up period, the presence of perio-endo disease, the use of non-bioceramic material as retrograde filling, longer extraoral time, and maxillary molar were found to be associated with lower healing rates. However, the differences between the subgroups were not statistically significant.
CONCLUSIONS: The present review showed IR yielded a good overall healing rate with a low complication rate. Taking the quality of evidence into account, more high-quality studies are required to evaluate the validity of the factors that may influence the treatment outcome of IR.