Background:The prevalence of root filled teeth (RFT) worldwide will inform about the amount of clinical activity of dentists dedicated to treat endodontic disease.Objectives: To carry out a systematic review with meta-analysis answering the following question: What is the prevalence of RFT around the world? The percentage of people with at least one RFT was also investigated.Methods: A systematic review including population-based studies using the following databases: PubMed, EMBASE and Scielo. Studies related to prevalence of RFT were included. The outcome of interest of the study was the prevalence of RFT. The meta-analyses were calculated with the Open Meta Analyst software to determine the global prevalence of RFT. Subgroups analyses were performed comparing geographical distribution, radiographic method and year of the study (classified in 20th or 21th century). The prevalence of people with at least one RFT was also analysed.Results: Seventy-four population-based studies fulfilled the inclusion criteria.Twenty-eight, forty-four and two studies reported high, moderate and low risk of bias, respectively. No obvious publication bias was observed. Prevalence of RFT was estimated with 1 201 255 teeth and 32 162 patients. The calculated worldwide prevalence of RFT was 8.2% (95% CI = 7.3%-9.1%; p < .001). The global prevalence of people with at least one RFT was 55.7% (95% CI = 49.6%-61.8%; p < .001). In 20th century, the prevalence of RFT was 10.2% (95% CI = 7.9%-12.5%; p < .001), whereas in the 21st century the overall calculated prevalence of RFT was 7.5% (95% CI = 6.5%-8.6%; p < .001). Brazilian people (12%) and the European population (9.3%) showed the highest prevalence of RFT. In Europe, 59.6% (95% CI = 52.4%-66.8%) of people has at least one RFT. Conclusions:This review showed that root canal treatment is a very common therapy throughout the world. More than half of the studied population have at least one RFT. A limitation of the present study is that most of the studies did not consider random sampling for population selection.

Aim. To conduct a systematic review and meta-analysis according to the following PICO question: in extracted human permanent teeth, does preflaring, compared with unflared canals, influence the accuracy of WL determination with EAL? Material and Methods. A systematic review was conducted according to the PRISMA checklist, using the following databases: PubMed, Science Direct, Scopus, and Web of Science. Studies related to WL determination using EAL both in preflared and unflared root canals of extracted human teeth were included. The outcome of interest was the accuracy of the electronic WL determination. A quality assessment of the included studies was performed, determining the risk of bias. The meta-analyses were calculated with the 5.4 RevMan software using the inverse variance method with random effects. PROSPERO registration: CRD42021243412. Results. Ten experimental studies fulfilled the inclusion criteria, and most of them found that preflaring increases the accuracy of the EALs in WL determination. The calculated OR was 1.98 (95% CI = 1.65–2.37; p < 0.00001; I2 = 10%), indicating that the determination of WL by EALs is almost twice as accurate in preflared canals. The accuracy of Root ZX in WL determination increases more than three times (OR = 3.25; p < 0.00001). Preflaring with Protaper files significantly increases the accuracy of EALs (OR = 1.76; p < 0.00001). The total risk of bias of the included studies was low. No obvious publication bias was observed. Conclusions. The results indicate a significant increase in the accuracy of WL determination with EAL after preflaring, doubling the percentage of exact measurements. Preflaring should be recommended as an important step during mechanical enlargement of the root canal, not only because it improves the access of the files to the canal, but also because it allows one to obtain more accurate electronic determinations of WL.

(1) Apical periodontitis (AP) is the inflammatory response of the periapical tissue to bacterial antigens and toxins arriving from inside the root canal after pulp necrosis. To control AP, it is necessary to interrupt the passage of antigens from the root canal to the periapex, which is achieved via a root canal treatment (RCT), which is the indicated endodontic therapy in cases of AP. The prevalence of root-filled teeth (RFT) is an indicator of the frequency of endodontic infections and the degree of dental care. Diabetes is associated with AP and has been identified as the main prognostic factor in RCT. The aim of this study was to carry out a systematic review with meta-analysis answering the following question: What is the prevalence of RFT among diabetic patients? (2) This study was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines 2020. A literature search was undertaken without limits on time or language until 12 January 2023 in PubMed-MEDLINE, Embase and Scielo. All studies reporting the prevalence of RFT among diabetic patients via radiographic examination; both panoramic and periapical radiographs were included. Meta-analyses were calculated with Open Meta Analyst software. The main outcome variable was the prevalence of RFT, calculated as the total number of RFT divided by the total number of teeth, which is expressed as a percentage. As a secondary outcome variable, the prevalence of diabetic patients with at least one RFT, expressed as a percentage, was also calculated. The quality of evidence of the included studies was analyzed according to the guidelines provided by the Centre for Evidence-Based Medicine in Oxford. The risk of bias was assessed using the Newcastle–Ottawa Scale, which was adapted for cross-sectional studies. To estimate the variance and heterogeneity amongst the trials, the Higgings I2 test was employed. (3) Eight studies fulfilled the inclusion criteria. Four studies were classified as having a high risk of bias, and four were classified as having a moderate risk of bias. The prevalence of RFT was estimated for 37,922 teeth and 1532 diabetic patients. The overall calculated prevalence of RFT among diabetic patients was 5.5% (95% CI = 4.1–6.9%; p < 0.001). The percentage of diabetics who had at least one RFT was 42.7% (95% CI = 23.9–61.4%; p < 0.001). (4) This systematic review and meta-analysis concluded that the prevalence of RFT among diabetic patients is 5.5%. More than 40% of diabetics have at least one RFT. In daily clinics, dentists should suspect that patients are undiagnosed diabetics when multiple RCT failures are observed in the same patient.