Root Canal Disinfection in Permanent Molars with Apical Lesion by Antimicrobial Photodynamic Therapy: Protocol for a Blind Randomized Clinical Trial.

Objective: The proposed study aims to compare the effectiveness of conventional endodontic treatment (ET) with that of ET associated with antimicrobial photodynamic therapy (aPDT) in patients with apical lesion. Methods: Controlled, double-blind, randomized clinical trial (RCT); superiority study with three parallel arms. Randomization will be conducted in exchange blocks of six, with allocation 1:1:1. The control group will receive conventional ET, while experimental group 1 (EG1) will receive conventional ET + aPDT with laser at 660 nm, fluence of 600 J/cm2; EG2 will receive conventional ET + aPDT with laser at 660 nm, fluence of 1200 J/cm2. The primary outcome will be canal disinfection before treatment, measured by analysis of colony formation (CFU/mL) and the success rate measured after 6 months on the clinical and radiographic evaluations. The mean and standard deviation will be calculated for continuous outcomes, and the CFU/mL mean between groups will be evaluated by ANOVA test. The Chi-squared test will be calculated for binary outcomes. A logistic regression analysis will be performed to assess differences in the success rate between groups, adjusted for the covariates. The Stata 18 software will be used, with a significance threshold of 5%. Conclusions: Few RCTs have evaluated the effectiveness of aPDT in root canal disinfection in patients with permanent dentition presenting apical lesion. New RCTs with larger numbers of participants are needed to support using aPDT as an adjuvant to conventional ET in root canal disinfection for routine use in clinical practice. The trial was registered prospectively in ClinicalTrials.gov (NCT05916859).

Application of personalized templates in minimally invasive management of coronal dens invaginatus: a report of two cases.

BACKGROUND: Treating the coronal dens invaginatus (CDI) with pulp infection commonly involves the removal of invagination, which increases the risk of perforation and fracture, and compromises the tooth structure. Minimally invasive endodontic management of CDI is highly recommended. This report describes two cases of type II CDI with the application of personalized templates. CASE PRESENTATION: Two cases of type II CDI, affecting the main root canal in a maxillary canine and a lateral incisor, were diagnosed. A guided endodontics (GE) approach was applied. Cone-beam computed tomography and intraoral scans were imported and aligned in a virtual planning software to design debridement routes and templates. The MICRO principle (which involves the aspects of Mechanical (M) debridement, Irrigation (I), Access cavities (C), Rectilinear routes (R), and Obstruction (O)) was proposed for designing optimal debridement routes for future applications. The templates were innovatively personalized and designed to preserve the tooth structure maximally while effectively debriding the root canal. Root canal treatment with supplementary disinfection was then performed. The follow-up of the two patients revealed favorable clinical and radiographic outcomes. CONCLUSIONS: The GE approach could be a feasible method for preserving healthy dental structure while effectively debriding the root canal, thereby achieving successful and minimally invasive endodontic treatment for CDI.

Frequency of apical periodontitis in root-filled teeth restored with post and core: A 5-year retrospective study.

BACKGROUND: In conjunction with post placement in root-filled teeth with periapical healthy conditions, root canal retreatment may be performed to improve the seal of the root canal. Whether root canal retreatment for technical reasons (retreatments in teeth without apical periodontitis (AP)) results in lower frequency of AP is unknown. OBJECTIVE: To examine whether there is a difference in frequency of AP between roots with root canals retreated for technical reasons, and roots with root canals not retreated before post placement, with a minimum follow-up of 5 years. Also, to examine changes in root filling quality following root canal retreatment for technical reasons. METHODS: This retrospective study included radiographs of 441 root-filled roots without periapical radiolucencies at baseline, scheduled for post and core treatment. Follow-up data for a minimum of 5 years were available for 305 roots (loss to follow-up 30.8%), 46 of which were retreated for technical reasons. Two calibrated observers assessed root filling sealing quality and length, respectively, and periapical status according to the Periapical Index. The main outcome of the study, AP, was used as the dependent variable and all analyses were performed at root level. RESULTS: The overall frequency of AP at follow-up was 13.8%. The difference in frequency of AP between retreated (4.3%) and nonretreated (15.4%) root canals was not statistically significant, p = .061. Analyses including only roots with preoperatively inadequate root filling quality showed a statistically significant difference (p = .017) between the two treatment groups (2.4% vs. 22.9%). CONCLUSIONS: Root canal retreatment for technical reasons before post and core placement significantly reduces the frequency of AP in roots with inadequate root filling quality.

Autotransplantation of an inverse impacted dilacerated incisor: a case report with 11-year follow-up.

BACKGROUND: Dilaceration can lead to impaction of maxillary incisors, resulting in both aesthetic and functional problems. This case report presents the multidisciplinary approach to managing an inverse impacted dilacerated left lateral incisor in a 9-year-old male patient. CASE REPORT: The orthodontic alignment of the remaining three incisors was achieved within six months. After using the diode laser to remove the gingiva covering the right lateral incisor during alignment process, a lingual button was bonded. The primary left canine and the impacted permanent left lateral incisor were extracted by raising the full-thickness mucoperiosteal flap, followed by the transplantation of the dilacerated lateral incisor into its correct position, splinted to the adjacent central incisors using composite resin. Root canal treatment was performed after the apical plug was created with mineral trioxide aggregate. The composite splint was removed after three weeks, and a new bracket was bonded to the left lateral incisor. It was left passively for 18 months until the permanent canines started to erupt. Light orthodontic forces were then applied for six months, and a passive eruption was expected over three months to properly position the canines within the dental arch. After an 11-year follow-up, the incisor displayed no clinical symptoms, although radiographic examination revealed external resorption in the long-term. CONCLUSION: This case demonstrates the successful and fast autotransplantation of an immature inverse impacted dilacerated incisor, highlighting the long-term clinical success and favorable aesthetic outcomes.

Managing failed vital pulp therapies in mature permanent teeth in a retrospective cohort study, with success and survival rates of managing protocols.

Despite advancements in vital pulp therapy (VPT), a subset of cases fails to achieve desired outcomes. This study based on a previous large-scale cohort study involving 1257 VPT-treated teeth, aiming to describe the demographic data and clinical characteristics of all failed cases and their management protocols. Clinical records/images of 105 failed cases treated by a single endodontist (2011-2022) were examined, including 10 extracted teeth. Asymptomatic cases with PDL widening received no intervention, while others underwent management protocols, including (selective) RCT and (tampon) re-VPT. These retreatments were assessed for success (defined as radiographic evidence of healing) and survival (characterized by the retention/function of the treated tooth) using Kaplan-Meier analysis. While 51.4% of all initial failures were diagnosed due to symptoms, 48.6% were symptom-free. Notably, failed cases with symptomatic irreversible pulpitis, and apical periodontitis/widened PDL before initial treatment significantly outnumbered asymptomatic cases and normal PDL, respectively (P = 0.001). Moreover, most of the initial failures were observed in teeth with composite resin rather than amalgam restorations (P = 0.002). The success and survival rates for the management protocols were 91.78% and 95.79%, respectively, over an average follow-up period of 36.94 (± 23.30) months. RCT and re-VPT procedures provide successful outcomes for managing unsuccessful VPTs.

Deciduous pulp tissue implantation into the root canal of mandibular incisor resulted in pulp revascularization: a case report with a 5-year follow-up.

To explore a new method to implant deciduous tooth pulp into the canal of young permanent teeth with necrotic pulps and apical periodontitis for the regenerative endodontic treatment of tooth no: 41 in a 7-year-old male. Briefly, 1.5% Sodium Hypochlorite (NaOCl) irrigation and calcium hydroxide-iodoform paste were used as root canal disinfectant at the first visit. After 2 weeks, the intracanal medication was removed, and the root canal was slowly rinsed with 17% Ethylene Diamine Tetraacetic Acid (EDTA), followed by flushing with 20 mL saline and then drying with paper points. Tooth no: 72 was extracted, and its pulp was extracted and subsequently implanted into the disinfected root canal along with induced apical bleeding. Calcium hydroxide iodoform paste was gently placed over the bleeding clot, and after forming a mineral trioxide aggregate (MTA) coronal barrier, the accessed cavities were restored using Z350 resin composite. The root developments were evaluated via radiographic imaging at 6 months, 1 year and 5 years after treatment. Imaging and clinical analysis showed closure of the apical foramen, thickening of the root canal wall, and satisfactory root length growth. Autologous transplantation might be useful to regenerate dental pulp in necrotic young permanent teeth.

Effect of fiber-reinforced direct restorative materials on the fracture resistance of endodontically treated mandibular molars restored with a conservative endodontic cavity design.

OBJECTIVE: This study aimed to evaluate the fracture strength of teeth restored using fiber-reinforced direct restorative materials after endodontic treatment with a conservative mesio-occlusal access cavity design. MATERIALS AND METHODS: A total of 100 extracted intact mandibular first molars were selected and distributed into a positive control group where teeth left intact and the following four test groups comprised of teeth with conservative mesio-occlusal access cavities that had undergone root canal treatment (n = 20/group): access cavity without restoration (negative control), bulk-fill resin composite with horizontal glass fiber post reinforcement, fiber-reinforced composite with bulk-fill resin and bulk-fill resin composite. Following thermocycling (10,000 cycles), fracture resistance was measured using a universal testing machine. Statistical analyses (one-way analysis of variance and the Tamhane test) were performed, and statistical significance was set at p < 0.05. RESULTS: Groups with minimally invasive access cavities had lower fracture strength than intact teeth, regardless of the restoration material (p < 0.05). Fiber-reinforced composite groups demonstrated higher fracture strength than bulk-fill resin composite alone (p < 0.05). Fracture types varied among groups, with restorable fractures predominant in the fiber-reinforced composite groups. CONCLUSION: This study suggests that using fiber-reinforced composite materials, especially in combination with bulk-fill resin composites, can effectively enhance the fracture strength of endodontically treated teeth with conservative access cavities. However, using only bulk-fill resin composite is not recommended based on the fracture strength results. CLINICAL SIGNIFICANCE: When teeth that undergo endodontic treatment are restored using a conservative access cavity design and fiber-reinforced composite materials, especially in combination with bulk-fill resin composites, the fracture strength of the teeth can be effectively increased.

Evaluation of Postoperative Pain after Using Dexamethasone Intracanal Rinse in Irreversible Pulpitis.

OBJECTIVE: To evaluate the efficacy of dexamethasone as a final intracanal rinse in relieving postoperative pain of teeth with symptomatic irreversible pulpitis. STUDY DESIGN: Randomised controlled trial. Place and Duration of the Study: Department of Operative Dentistry, PIMS, Islamabad, Pakistan, from June 2019 to December 2020. METHODOLOGY: Sixty patients aged 18- 50 years diagnosed with symptomatic irreversible pulpitis were selected according to the inclusion criterion. After obtaining informed consent, root canal therapy (RCT) was initiated under rubber dam. Pulpectomy was done followed by canal preparation. The lottery method was utilised for the division of patients. Group A (experimental) received dexamethasone (4mg/ml in 5ml syringe) as a final rinse, while Group B (control group) recalled after 1 week and asked whether their pain had relieved or not as a yes/no question. After data collection teeth were obturated and permanent restoration was placed. Data were analysed using Chi-square test. RESULTS: The efficacy of dexamethasone as a final intracanal rinse was greater than saline 86.67% and 20.0%, respectively (p < 0.05) in relieving postoperative pain in teeth with symptomatic irreversible pulpitis. CONCLUSION: Dexamethasone was proved to be more efficacious than saline in alleviating postoperative pain when used as a final intracanal rinse after canal instrumentation. KEY WORDS: Irreversible pulpitis, Dexamethasone, Postoperative pain, Pulpectomy.

Atypical healing of an endodontic lesion following emergency treatment: a case report.

This case report examines the atypical healing of an endodontic lesion without standard endodontic treatment, influenced by the patient's failure to attend treatment appointments. A 50-year-old woman with no notable medical history presented with a deep carious lesion on her mandibular right first molar, accompanied by localized pain. Citing forgetfulness as a reason, the patient missed her initially scheduled root canal treatment, necessitating an emergency intervention. The emergency treatment included access cavity preparation, irrigation with 5.25% sodium hypochlorite solution, application of a modified triple antibiotic paste (equal parts penicillin G, metronidazole, and ciprofloxacin), and temporary restoration with amalgam. A large apical lesion was detected in immediate postoperative radiographs. However, the patient failed to return for definitive endodontic treatment, due to a lack of symptoms and time for treatment. Follow-up examinations 1 and 5 years after emergency treatment disclosed gradual healing of the lesion, culminating in the establishment of a normal periodontal ligament. This case underscores the potential efficacy of a modified triple antibiotic paste and highlights the importance of a well-sealed coronal restoration in promoting the healing of endodontic lesions, even in the absence of pulpectomy and conventional root canal therapy. Additional research is needed to understand the mechanisms behind such healing events.

Survival of endodontically treated teeth in public dental service in Northern Finland: a practise-based register study.

OBJECTIVE: The aim of this study was to explore the factors associated with the survival of root canal treated teeth in a practise-based study setting in a 5-year period. MATERIAL AND METHODS: This retrospective study used data from the electronic patient registration system of the public dental services of the City of Oulu, Finland. The inclusion criteria for this study were patients aged ≥ 20 years who had root canal treatment (RCT) that was initiated in 2014. One RCT per patient was included in the study. A total of 713 patients met the inclusion criteria. The outcome variable for this study was the extraction of the RCT tooth during the 5-year period. Explanatory variables included age, diagnosis, tooth type (incisive, canine, premolar, molar), RCT technique (manual, motorized), time from RCT initiation to final restoration and type of final restoration (composite, glass ionomer, fixed dental prosthesis). To evaluate the association between the outcome variable and explanatory variables, Cox regression analyses were performed. RESULTS: The overall survival rate was 91%. The middle-aged (40-59-years-old) and the oldest (60 and older) patients had a two-fold risk of extraction compared to younger (20-40-years-old) patients. Similarly, a short length of time from RCT initiation to final restoration (0-14 days) resulted in a nearly three times higher risk of extraction compared to a longer period (≥ 90 days). CONCLUSIONS: The 5-year survival rate of RCTs seems high. Extractions were more common among patients over 40 years of age and if the RCT was completed shortly after its initiation.

A novel surgical treatment approach for the vertical root fracture of posterior teeth: a case report with 24-month review.

BACKGROUND: Up to 25% of the tooth extraction after root canal treatment could be attributed to the vertical root fracture (VRF). The treatment choice for teeth with VRF would mostly be the extraction despite some repairing methods were also reported. The repairing treatment result of VRF would mostly depend on the fixation strength and the bioactivity of the repairing materials, especially for the posterior teeth with high masticating stresses. This case report designed a novel surgical treatment approach for the VRF of posterior teeth. METHODS: a maxillary premolar with buccal-palatal complete VRF was treated with a new dual-layered repairing approach using adhesive resin + iRoot BP Plus bioceramic cement to fill the modified fracture line with retention forms through the intentional replantation. RESULTS: At the 24-month review, the tooth showed desirable periodontal healing and normal function. CONCLUSIONS: This case report indicated that the dual-layered repairing approach might be effective for saving the posterior teeth with VRF. Nevertheless, further clinical trials are needed for its long-term result.

Molar root canal treatment performed by undergraduate dental students; an observational study of procedural errors and student perception.

BACKGROUND: Molar root canal treatment (RCT) is challenging and requires training and specific skills. Rotary instrumentation (RI) reduces the time needed for instrumentation but may increase the risk of certain procedural errors. The aims of this study were to evaluate the quality of molar RCTs provided by undergraduate students, to compare the prevalence of procedural errors following manual and RI, and to assess the students' self-perceived confidence to perform molar RCT without supervision and their preference for either manual or RI. METHODS: Molar RCTs performed by the final year students were evaluated radiographically according to predefined criteria (Appendix 1). The procedural errors, treatment details, and the students' self-perceived confidence to perform molar RCT and their preference for either manual or RI were recorded. Descriptive statistics were performed, and the Chi-squared test was used to detect any statistically significant differences. RESULTS: 60.4% of RCTs were insufficient. RI resulted in more sufficient treatments compared with MI (49% vs. 30.3% respectively. X2: 7.39, p = 0.007), required fewer visits to complete (2.9 vs. 4.6 respectively. X2: 67.23, p < 0.001) and was the preferred technique by 93.1% of students. The most common procedural errors were underextension of the root canal obturation (48.4%), insufficient obturation (45.5%), and improper coronal seal (35.2%) without a significant difference between the two techniques. 26.4% of the participating students reported that they did not feel confident to perform molar RCT without supervision. CONCLUSION: The quality of molar RCT provided by UG students was generally insufficient. RI partially improved the technical quality of RCT compared with MI. UG students need further endodontic training and experience before they can safely and confidently practise molar RCT.

The effect of apical patency on postoperative pain following endodontic therapy: A systematic review and meta-analysis.

This systematic review and meta-analysis aimed to determine whether apical patency increases postoperative pain after endodontic therapy. This study explored the degree and incidence of postoperative pain during root canal therapy, as well as the number of required analgesic doses. We searched PubMed, Scopus, Embase, Web of Science, Cochrane Library, and gray literature from the date of database inception until May 2023. RevMan 5.4 software was used for data analysis. Twelve studies were considered eligible for meta-analysis. The mean pain scores on days 1 (mean difference [MD] = -1.69) and 2 (MD = -0.85) differed significantly between the apical patency and non-patency groups. The odds for pain after 24 h were significantly lower (OR 0.59) in the apical patency group than in the non-patency group. Furthermore, the mean number of required analgesic doses was not significantly different between the two groups. In conclusion, apical patency significantly alleviated postoperative pain (low-quality evidence) and reduced the incidence of pain (moderate evidence). However, high-quality randomized controlled trials are required to validate these findings.

Comparative evaluation of resin-based sealers and bioceramic sealers for postoperative pain after endodontic treatment: A systematic review.

The systematic review aimed to compare and evaluate the effect of resin-based sealers and bioceramic sealers on postoperative pain after endodontic treatment. Two reviewers independently conducted electronic search in PubMed, the Web of Science, ScienceDirect, the Wiley Online Library, SpringerLink, Google Scholar, and the Cochrane Library, employing a complete dual-review process to ensure the inclusion of all relevant studies in the review. The search was carried out until November 2021. After selecting eligible studies, the risk of bias assessment was carried out using the revised Cochrane risk-ofbias tool for randomized trials (RoB 2). A total of 1,931 studies were identified from the electronic search, and finally 10 studies were included after full-text assessment. In all our included studies, the visual analog scale (VAS) was used for recording pain scores. Most of the studies recorded pain intensity starting from 6 h to 7 days. The results showed that there was no significant difference between resin-based sealers and bioceramic sealers in terms of incidence or intensity of postoperative pain at any point in time.

Efficacy of non-instrumental Endodontic treatment in primary teeth: a systematic review of clinical randomized trials.

BACKGROUND: Endodontic therapy in pediatric dentistry is a challenging procedure, especially for special needs, uncooperative, and very young patients. A new conservative approach which is the non-instrumental endodontic treatment (NIET) has been developed to simplify the management of primary teeth requiring pulpectomy. This review aimed to compare the efficiency of NIET and conventional endodontic treatment in primary teeth. METHODS: Electronic databases including MEDLINE (via PubMed), Cochrane Library (CENTRAL), and Scopus without restrictions on publication year or publication language were searched. Only randomized clinical trials reporting clinical and radiographical outcomes of NIET and conventional pulpectomy on primary teeth were considered eligible. Two reviewers extracted the data according to the PRISMA statement and assessed the bias risk using the revised Cochrane risk-of-bias tool and a meta-analysis was performed. RESULTS: From 3322 screened articles, seven articles meeting the inclusion criteria were included. The selected studies included 283 primary molars, of 213 children aged between 3 and 9 years, treated by NIET and conventional pulpectomy, and had follow-up periods ranging from 1 month to tooth exfoliation. Two studies reported good success rates for both the NIET technique and endodontic therapy with no statistically significant difference while three studies showed radiographical significant differences with a low success rate for the NIET technique. Only one study reported better outcomes in the pulpectomy group with statistically significant differences. The quantitative grouping of the included studies showed no significant differences between NIET and conventional endodontic therapy regarding clinical and radiographical success (p value > 0.05). CONCLUSION: No difference between the NIET technique and the conventional endodontic therapy in primary molars requiring pulpectomy could be confirmed. Results of the present review need to be interpreted with caution since the quality of evidence according to the GRADE was considered as moderate to very low. Therefore, additional clinical trials on the NIET technique are recommended.

Dentists' knowledge of non-surgical root canal treatment, a systematic review.

OBJECTIVES: Dental practice is based upon dentists' cognitions, knowledge being foundational. Knowledge is attained through education and perception. Although knowledge is modulated by beliefs, attitudes, preferences, and behaviors, it is essential to evidence-based practice. Cross-sectional studies uniformly demonstrate that community NSRCT is of sub-optimal quality worldwide, is lack of knowledge a problem? Our purpose was to measure dentists' knowledge of root canal treatment (NSRCT). DATA: Quantitative and qualitative data were extracted: purpose, topics assessed, authors cited knowledge sources, number of dentists studied, number of questions, authors descriptors of knowledge level,% correct answers by question, authors recommendations. SOURCES: OVID Medline, EMBASE, Web of Science, and hand-searching. STUDY SELECTION: Studies which had measured dentists' knowledge of non-surgical root canal treatment that was valuable, reliable, and had practical implications which could be implemented. A total of 51 papers from 19 countries measured the knowledge of 15,580 dentists using 445 questions on 29 root canal treatment topics. CONCLUSIONS: 'Gold standards' were from literature, external bodies, or expert consensus in 47, 31, and 2 papers respectively. Levels of knowledge by percentage correct answers among studies were poor to moderate and varied considerably. The mean, for the 50 studies where overall study percentages could be calculated, was 57 %, standard deviation 17 %, and a range of 16 % to 82 %. Authors' adjectives describing knowledge levels were generally negative. Additional education was advised in 49 papers, but without evidence that education was inadequate; 6 papers recommended increased use of protocols; only 5 papers advocated research on the cause of lack of knowledge. CLINICAL SIGNIFICANCE: Dentists' root canal treatment knowledge was found to be poor to moderate, as well variable. This may constrain quality of care. However, provision of information without attention to dentists' cognitions and motivations may not be successful. Educational strategies and goals should be re-evaluated. Evidence-based practice faces many barriers.

Amputação radicular para preservação de elemento dentário / Root amputation for tooth preservation

A periodontite é uma doença inflamatória crônica dos tecidos de sustentação e proteção dos dentes. Em dentes posteriores, a perda de inserção pode resultar em vários graus de dano à furca, que se refere à destruição dos tecidos de suporte de dentes multirradiculares caracterizada por reabsorção óssea e perda de inserção no espaço interarradicular. Independente do grau de envolvimento da furca, o tratamento periodontal básico (RAR) é a primeira opção para estabilizar a periodontite, contudo, em algumas situações é utilizada uma terapia cirúrgica periodontal bastante conhecida: a rizectomia ou amputação radicular. O objetivo do trabalho é relatar o caso de uma amputação radicular de um dente comprometido periodontalmente, a fim de se preservar o elemento dentário. O dente 27 foi diagnosticado com periodontite, o que ocasionou a lesão de furca grau III. O tratamento endodôntico foi realizado prévio ao procedimento cirúrgico, viabilizando a amputação da raiz disto-vestibular deste elemento. A partir do relato deste caso, se pode concluir que a amputação radicular é considerada um procedimento conservador, capaz de manter em função molares com histórico de periodontite associado ao envolvimento de lesões de furca(AU)

Periodontitis is a chronic inflammatory disease of the supporting and protective tissues of the teeth. In posterior teeth, attachment loss can result in varying degrees of damage to the furcation, which refers to the destruction of the supporting tissues of multirooted teeth characterized by bone resorption and attachment loss in the interarticular space. Regardless of the degree of furcation involvement, basic periodontal treatment (RAR) is the first option to stabilize periodontitis; however, in some situations, a well-known periodontal surgical therapy is used: rhizectomy or root amputation. Rhizectomy is a treatment option for multirooted teeth. The technique preserves the crown and requires endodontic treatment of the affected tooth, preferably done before surgery(AU)

The evaluation of effective rate and pain intensity of root canal treatment in primary teeth-a retrospective study.

Two-visit root canal treatment for children reduce the time of visits and the by-chair time in comparison with the three-visit root canal treatment. However, it is not clear whether two-visit root canal treatment increase the risk of complications. This study aimed to evaluate the clinical effects and post-operative pain intensity after the root canal treatment between two-visit and three-visit groups in primary molars from children.106 patients were screened for eligibility, of which 74 went back to the preservation visit. Therefore, 74 primary molars from 74 children that diagnosed with chronic pulp and periodontal tissue diseases in the clinics of pediatric dentistry were retrospectively analyzed, in which 37 in the two-visit group and 37 in the three-visit group. The total effective rate and postoperative pain intensity were assessed after treatment and all statistical data were carried out with SPSS software.The average age of children in the two-visit and three-visit groups was 6.4 and 7.0, respectively, with no significant difference (p = 0.056). The two-visit group consisted of 59.5% male and 40.5% female children, while the three-visit group consisted of 56.8% male children and 43.2% female children (p = 0.813). Two months after treatment, the total effective rate in the three-visit group was 97.30%, a little higher than that in the two-visit group (94.59%), but with no significant difference (p = 0.201). Besides, there was also no significant difference in pain intensity between the two-visit and three-visit groups (p = 0.692). Therefore, there were no significant difference of total effective rate and pain intensity in root canal treatment between the two-visit and three-visit groups in primary molars from children.