Platelet-rich fibrin as an apical barrier for MTA placement in the treatment of teeth with open apices: a pilot study.

OBJECTIVE: The aim of the present pilot study was to assess the effectiveness of the platelet-rich fibrin (PRF) apical barrier for the placement of MTA for the treatment of teeth with periapical lesions and open apices. METHODS: A total of thirty teeth on twenty-eight patients with open apices and periapical periodontitis were enrolled and divided into two groups in the present pilot study. In the PRF group (fourteen teeth in thirteen patients), nonsurgical endodontic treatment was performed using PRF as an apical matrix, after which the apical plug of the MTA was created. For the non-PRF group (fourteen teeth in fourteen patients), nonsurgical endodontic therapy was performed using only the MTA for an apical plug with no further periapical intervention. Clinical findings and periapical digital radiographs were used for evaluating the healing progress after periodic follow-ups of 1, 3, 6, and 9 months. The horizontal dimension of the periapical lesion was gauged, and the changes in the dimensions were recorded each time. The Friedman test, Dunn-Bonferroni post hoc correction, and Mann-Whitney U test were used for statistical analysis, with P < 0.05 serving as the threshold for determining statistical significance. RESULTS: All patients in both groups in the present pilot study had no clinical symptoms after 1 month, with a significant reduction in the periapical lesion after periodic appointments. The lesion width of the PRF group was significantly smaller than that of the non-PRF group in the sixth and ninth month after treatment. CONCLUSIONS: PRF is a promising apical barrier matrix when combined with MTA for the treatment of teeth with open apices and periapical periodontitis. Small number of study subjects and the short time of follow-up period limit the generalizability of these results. TRIAL REGISTRATION: TCTR, TCTR20221109006. Registered 09 November 2022 - Retrospectively registered, https://www.thaiclinicaltrials.org/show/TCTR20221109006 .

Dental findings frequently overlooked in sinus computed tomography reports.

OBJECTIVES: Computed tomography (CT) and cone beam computed tomography (CBCT) represent the main imaging modalities used in rhinosinusitis patients and are also important in odontogenic sinusitis (OS) diagnostics. Reports, however, often lack information on dentition. Here, we aimed to determine how maxillary dentition is initially interpreted in rhinosinusitis patients' CT/CBCT reports and which dental findings in particular are potentially missed, thus needing more attention. STUDY DESIGN: CT/CBCT scans and radiological reports from 300 rhinosinusitis patients were analysed focusing specifically on dental findings. An experienced oral and maxillofacial radiologist re-evaluated the scans and the assessment was compared to the original reports using the McNemar test. RESULTS: From the 300 original reports, 233 (77.7%) mentioned the maxillary teeth. The most frequent statement (126/300, 42.0%) was 'no apical periodontitis'. Apical periodontitis and severe alveolar bone loss were significantly overlooked (p < 0.001). Amongst the 225 patients for whom the CT/CBCT report initially lacked information on dental pathology, 22 patients were diagnosed with apical periodontitis and 16 with severe alveolar bone loss upon re-evaluation. CONCLUSIONS: Dental pathology remains underreported in rhinosinusitis patients' CT/CBCT reports. Because these reports affect OS diagnostics, a routine and structured review of the maxillary teeth by a radiologist is necessary. Such examinations should encompass the maxillary teeth.

Pathogenic factors of maxillary sinus mucosal thickening observed by cone-beam computed tomography (CBCT).

OBJECTIVE: To explore the pathogenic factors associated with maxillary sinus mucosal thickening with Cone-beam computed Tomography (CBCT). METHODS: From 2016 through 2020, 93 patients with periapical periodontitis or periodontitis in the maxillary posterior dental region were selected. RESULTS: The preoperative thickness of the periodontitis group was significantly higher than that of the periapical periodontitis group (P < 0.05). The difference achieves statistical significance for the comparison of the thickness change with various severity of inflammation (F = 54.824, P = 0.000), the change with time (F = 312.741, P = 0.000). and the change with the interaction severity of inflammation and time（F = 86.132, P = 0.000). CONCLUSIONS: Patients with maxillary sinus mucosa thickening caused by periodontitis and periapical periodontitis should be extracted their infectious teeth and get thoroughly debridement. Maxillary sinus augmentation can perform favorable efforts 3-6 months after extracting teeth.

Clinical and Radiographic Failure of Nonsurgical Endodontic Treatment and Retreatment Using Single-cone Technique With Calcium Silicate-based Sealers: A Systematic Review and Meta-analysis.

INTRODUCTION: This systematic review and meta-analysis aimed to evaluate the clinical and radiographic failure of nonsurgical endodontic treatment and retreatment for mature permanent teeth with or without apical periodontitis using the single-cone (SC) obturation technique with calcium silicate-based bio-ceramic (CSBC) sealers and to compare these failure rates to other sealer materials and obturation techniques. METHODS: A comprehensive search was conducted using MEDLINE (PubMed), Embase, Cochrane Library, Scopus, Web of Science, and gray literature up to March 2023. Two reviewers assessed the eligibility of the included studies. Eligible studies were critically appraised for risk of bias and quality of evidence. Subsequently, a meta-analysis of pooled data was conducted utilizing the RevMan software (P < .05) to evaluate the failure rate of non-surgical root canal therapy using CSBC sealers and SC obturation procedures. Separately, another analysis was conducted to compare those results with the outcome of nonsurgical root canal therapy using alternative obturation materials and methods. RESULTS: Five studies were included. The pooled failure rate for nonsurgical endodontic treatment and retreatment combined using CSBC sealers and SC obturation technique was 6.8% [95% confidence interval (CI) = (3%-12%), I2 = 46%]. A second analysis was conducted on the 3 included clinical trials to compare the outcomes of the intervention (CSBC sealers and SC obturation technique) and control groups (other sealers and other obturation techniques). This analysis found no significant difference between the 2 groups regarding clinical and radiographic failure of endodontic treatment and retreatment [Risk ratio = 0.71, 95% CI = (0.33, 1.51), I2 = 0]. This difference was also not statistically significant when the failure rate of primary root canal treatment and retreatment were separately analyzed [Combined Risk ratio of primary root canal treatment = 0.94, 95% CI = (0.46, 1.93), I2 = 0%; Combined Risk ratio of retreatment = 0.21, 95% CI = (0.001, 75.46), I2 = 0%]. CONCLUSIONS: The overall results of this systematic review and meta-analysis demonstrate that the SC obturation technique with CSBC sealer provides similar results compared to other obturation materials and techniques in facilitating the healing of apical periodontitis.

A 22-year follow-up cross-sectional study on periapical health in relation to the quality of root canal treatment in a Belgian population.

AIM: To investigate the prevalence of apical periodontitis (AP) and the technical standard of root canal treatment in a Belgian population, assess the association of different variables with periapical status, and compare the results to a similar study conducted 22 years previously. METHODOLOGY: In this cross-sectional study, 614 panoramic radiographs of first-time adult attendees at the Dental School of the University Hospital of Ghent were examined. Recorded patient-level parameters included gender, age, number of teeth, number of root filled teeth, presence of any AP lesion, and number of implants. The following tooth-level data were collected: tooth presence, coronal status, quality of coronal restoration, post presence, type of root-filling material, length and density of root filling, root-end filling material, presence of AP, and adjacent implant. Multivariable multilevel binary logistic regression was used to explore the association between patient and tooth characteristics and AP prevalence. Risk differences and confidence intervals were calculated to compare the present with the previous study. RESULTS: The prevalence of AP at patient and tooth level was 46.9% and 5.6%, respectively. Fifty-one per cent of the 614 patients had at least one root filled tooth, and 5.9% of the 14 655 teeth studied were root filled. AP was found in 45% of root filled teeth. Fifty-four per cent of the root-filled teeth were rated as inadequate. Multivariable multilevel logistic regression revealed that more teeth, more implants, fewer root-filled teeth, adequate density, adequate coronal restoration, and no caries reduced the likelihood of AP. There were no statistically significant differences between the two studies regarding the prevalence of root-filled teeth or AP and the technical quality of root canal treatment. CONCLUSIONS: The prevalence of AP and the technical quality of root canal treatment in Belgium have not substantially changed over the last 22 years, despite the technological advancements and continuing education in the field.

Bone Resorption in Apical Periodontitis Enhanced by Cigarette Smoke Inhalation: Histometric, Immunohistochemical, and Microtomographic Analysis in Rats.

INTRODUCTION: This study evaluated the effects of cigarette smoke inhalation (CSI) on apical periodontitis (AP) induced in rats by histometric, immunohistochemical, and microtomographic analysis. METHODS: A total of 32 male Wistar rats were divided into 4 experimental groups (n = 8): control, CSI, AP, and CSI + AP. Rats in the CSI and CSI + AP groups inhaled cigarette smoke by remaining inside a smoking chamber for 8 minutes 3 times a day for 50 days. After 20 days of smoke inhalation, rats in the AP and CSI + AP groups had the pulp of their first right lower molar exposed to induce AP. Blood was collected on day 50 to evaluate nicotine and serum cotinine levels. The animals' mandibles were removed for histologic processing to evaluate bone resorption by histometric, immunohistochemical (receptor activator of nuclear factor kappa B ligand/osteoprotegerin), and microtomographic analysis. The Student t test was applied. RESULTS: Histometric analysis showed a larger area of bone resorption (P < .05) and microtomographic analysis found greater resorption volume (P < .001) for the CSI + AP group compared with the AP group. The CSI + AP group presented a high RANKL immunostaining pattern compared with the AP group (P < .001). CONCLUSIONS: CSI increased bone resorption caused by AP.

Association between apical periodontitis and secondary outcomes of atherosclerotic cardiovascular disease: A case-control study.

AIM: To evaluate the association between apical periodontitis (AP) and atherosclerotic cardiovascular disease (ASCDV). METHODOLOGY: A total of 65 periodontally and systemically healthy patients (age ≥ 40 years) were included in the study. Periapical status was assessed through dental examination and periapical radiographs; 33 subjects had AP (AP+), while 32 acted as control (AP-). Moreover, data regarding their periapical index (PAI) score and the Decayed, Missing, and Filled Teeth (DMFT) index were recorded. All subjects underwent echo-colour Doppler assessment of carotid intima-media thickness (CIMT), carotid plaques, degree of stenosis using the North American Symptomatic Carotid Surgery Trial (NASCET) method, maximum diameter of the abdominal aorta (maximum AA) and common iliac arteries (CIA) diameters. Furthermore, peripheral blood flow was also measured using the ankle-brachial index (ABI). Simple and multiple regression analyses were performed. RESULTS: Among AP+ patients, 57.58% disclosed at least one sign of subclinical carotid atherosclerosis. Multiple regression analysis identified AP as a significant risk indicator for carotid plaques [OR = 4.87 (1.27, 18.98; p = .021)] and marked carotid intima-media thickenings (OR = 14.58 [1.22, 176.15], p = .035). A significant association was established between AP and other cardiovascular (CV) variables (CIMT, NASCET, and maximum AA). On the contrary, a higher PAI score does not correlate to increased odds of carotid alterations, and the presence of AP did not prove any significant change in CIA and ABI. No significant correlation was established between DMFT and other variables. CONCLUSIONS: Results from the current study highlight that the presence of AP may be regarded as a risk indicator for ASCVD, with AP being associated with 5-fold increased odds of having carotid plaques and 15-fold increased odds of having marked carotid intima-media thickenings. Further studies should be conducted in order to verify whether AP treatment could be beneficial for ASCVD signs.

Radiographic Criteria for Differential Diagnosis Between Vertical Root Fracture and Apical Periodontitis in Single-Rooted Endodontically Treated Premolars Using Cone-Beam Computed Tomography.

INTRODUCTION: This study explores the differences between the patterns of bone defects associated with vertical root fracture (VRF) and apical periodontitis (AP) in single-rooted endodontically treated premolars (SRETPs) based on cone-beam computed tomography (CBCT) data. METHODS: Eighty-four SRETPs were extracted and categorized into the VRF and AP groups. On preoperative CBCT images, the location of bone defects according to the root thirds in buccolingual and mesiodistal directions across the study groups were compared. RESULTS: The majority of bone defects in the VRF group were longitudinal and combined, involving more than one root thirds in buccolingual and mesiodistal directions simultaneously. A uniform approach to comparing bone defects using the sites of periradicular area with bone loss as a comparison unit was developed. In the VRF group, bone loss sites in the middle and coronal thirds were detected more often and were located mainly buccolingually compared with the AP group (P < .001). CONCLUSION: Bone defects in the middle or middle and coronal root thirds in the buccolingual direction may be potential radiographic signs useful in differentiating between VRF and AP in SRETPs. The introduction of the uniform approach to assessment of bone loss patterns will give practitioners a single simple tool and improve the quality of endodontic treatment.

A novel simplified approach for endodontic retrograde surgery in short single-rooted teeth.

BACKGROUND: High technical thresholds, long operative times, and the need for expensive and specialized equipment impede the widespread adoption of endodontic microsurgery in many developing countries. This study aimed to compare the effects of a simplified, cost-effective, and time-efficient surgical approach involving orthograde obturation using biological ceramic material greater than 6 mm combined with apicoectomy for single-rooted teeth with short lengths with those of the conventional and current standard methods. MATERIALS AND METHODS: Forty-five premolars equally categorized into three groups: conventional surgery group, standard surgery group, and modified surgery group. A µCT scan was used to calculate the volume of voids. A micro-leakage test and scanning electron microscope (SEM) were performed to assess the sealing effect. Additionally, four cases of chronic periapical periodontitis in the anterior region were selected, and the patients received either the modified approach or the standard surgery for endodontic microsurgery. RESULTS: The volumes of voids in the apical 0-3 mm of the modified group and the standard group were comparable. The micro-leakage test and SEM examination demonstrated closely bonded fillings in the dentinal walls in both the modified surgery group and standard surgery group. The outcomes of the preliminary application of this modified procedure on patients were successful at the time of the follow-up cutoff. CONCLUSIONS: The modified surgery group exhibited similar root canal filling and apical sealing abilities with the standard procedure for single-rooted teeth with short lengths (< 20 mm). The preliminary application of this modified surgical procedure achieved favorable results.

Clinically Oriented CBCT Periapical Lesion Evaluation via 3D CNN Algorithm.

Apical periodontitis (AP) is one of the most prevalent disorders in dentistry. However, it can be underdiagnosed in asymptomatic patients. In addition, the perioperative evaluation of 3-dimensional (3D) lesion volume is of great clinical relevance, but the required slice-by-slice manual delineation method is time- and labor-intensive. Here, for quickly and accurately detecting and segmenting periapical lesions (PALs) associated with AP on cone beam computed tomography (CBCT) images, we proposed and geographically validated a novel 3D deep convolutional neural network algorithm, named PAL-Net. On the internal 5-fold cross-validation set, our PAL-Net achieved an area under the receiver operating characteristic curve (AUC) of 0.98. The algorithm also improved the diagnostic performance of dentists with varying levels of experience, as evidenced by their enhanced average AUC values (junior dentists: 0.89-0.94; senior dentists: 0.91-0.93), and significantly reduced the diagnostic time (junior dentists: 69.3 min faster; senior dentists: 32.4 min faster). Moreover, our PAL-Net achieved an average Dice similarity coefficient over 0.87 (0.85-0.88), which is superior or comparable to that of other existing state-of-the-art PAL segmentation algorithms. Furthermore, we validated the generalizability of the PAL-Net system using multiple external data sets from Central, East, and North China, showing that our PAL-Net has strong robustness. Our PAL-Net can help improve the diagnostic performance and speed of dentists working from CBCT images, provide clinically relevant volume information to dentists, and can potentially be applied in dental clinics, especially without expert-level dentists or radiologists.

Bacteriologic Conditions of the Apical Root Canal System of Teeth with and without Posttreatment Apical Periodontitis: A Correlative Multianalytical Approach.

INTRODUCTION: This study used a correlative multianalytical approach to investigate the bacteriologic conditions in the apical root canal system of treated teeth with or without apical periodontitis and their correlation with the technical quality of the previous root canal obturation and the presence and volume of apical periodontitis lesions. METHODS: Root apexes were obtained from recently extracted root canal-treated teeth with (n = 23) and without (n = 22) apical periodontitis lesions as demonstrated by cone-beam computed tomographic examination. The root apexes were sectioned and subjected to micro-computed tomographic (micro-CT) scanning. The specimens were cryopulverized, and DNA extracted from the powder was used as a template in real-time polymerase chain reaction assays to quantify total bacteria and members of the Streptococcus genus and Actinobacteria phylum. The bacteriologic findings were compared between the 2 groups and also evaluated for associations with cone-beam computed tomographic and micro-computed tomographic data. RESULTS: Bacteria were detected in all apical canal samples except 1. The mean counts of total bacteria, streptococci, and actinobacteria did not differ significantly between teeth with or without apical periodontitis (P > .05). Streptococcus levels were significantly lower by 80% in the apical canals of teeth with small lesions compared with those without lesions (P < .05). The limit of filling >2 mm short was significantly associated with more total bacterial counts compared with canals filled 0-2 mm short (P < .05). An adequate coronal restoration was significantly associated with lesser counts of Streptococcus (P < .05). CONCLUSIONS: Comparable bacterial loads were observed in the apical canal system of treated teeth with and without apical periodontitis, suggesting that factors other than only the total bacterial levels may also influence the development and progression of apical periodontitis. Bacteria were found in the apical canal in virtually all cases with a high prevalence of streptococci and actinobacteria. Streptococci counts were significantly higher in the apical canal of teeth with inadequate restorations and teeth with no lesions. Underfilled canals showed higher bacterial counts.

Six-year clinical evaluation of iRoot BP Plus as apical barrier in permanent teeth of periapical periodontitis.

The apical barrier technique in permanent teeth with extensive destruction of the periapical tissue and a long infection time is much more difficult to succeed, which is a clinical challenge. This study aimed to evaluate the long-term effects of iRoot BP Plus as an apical material in adult teeth. Fifty incisors and premolars were chosen for this study. All teeth were performed apical barrier with the same operator. After treatment, the teeth were clinically and radiographically evaluated at 1, 2 and 6 years. At the 1-year follow-up, 35 teeth had healed, and three patients developed an apical abscess due to root fracture at the 2-year follow-up. Six years postoperatively, one tooth showed root resorption, which was considered a failure. The long clinical evaluation confirmed that iRoot BP Plus is a suitable material for the apical barrier of mature teeth with open apices and periapical lesions.

Outcome of single-visit root canal treatment with or without MTAD: A randomized controlled clinical trial.

AIM: This study aimed to investigate 2-year changes in periapical trabecular patterns in single-rooted teeth with apical periodontitis using fractal analysis and periapical index (PAI) after root canal treatment performed with or without BioPure MTAD solution. METHODOLOGY: In this randomized clinical trial, 100 patients were selected and randomized to either the BioPure MTAD or the control groups. Initial periapical radiographs were obtained for each participant before and 2 years after root canal treatment. The region of interest in the periapical lesion around the root apex was selected from the paired periapical radiographs, and then, the fractal dimension (FD) was calculated. With regards to the classification of periapical status, PAI was labelled as "healed" (PAI ≤ 2) or "unhealed" (PAI ≥ 3). RESULTS: After 24 months, 28 patients did not comply with the follow-up and the data of 72 patients were compared. When the initial and the follow-up PAI scores were compared, the decrease was statistically significant in 33 of 37 teeth (89.2%) and 32 of 35 teeth (91.4%) in the BioPure MTAD and control group, respectively. In both groups, statistically significant increases were observed in FD values after 2 years in all patients (p < .001). No significant difference was found between the two groups amongst decreased PAI scores and increased FD values. CONCLUSIONS: Root canal treatments with or without BioPure MTAD irrigation contributed to periapical healing in single-visit root canal treatment. Two years after root canal treatment, the extent of the periapical trabecular bone radiographically increased, as the FD and PAI data revealed.

Presence of methanogenic archaea in necrotic root canals of patients with or without type 2 diabetes mellitus.

Theoretically, a necrotic root canal fulfils all requirements as a niche for methanogens to inhabit. However, their presence in it and its implication in apical periodontitis (AP) is controversial. Therefore, to contribute to ending the controversy, this study aimed to detect and compare methanogens' presence in two distinct niches with supposedly different microenvironments; both were necrotic root canals associated with AP but one from patients with type 2 diabetes mellitus (T2DM) while the other from non-diabetic patients. A clinical examination was performed on 65 T2DM patients and 73 non-diabetic controls. Samples from necrotic root canals were obtained, and methanogens were identified. The presence of methanogens was three times higher (27.6%) in the T2DM group than in non-diabetic patients (8.2%). In addition, methanogens' presence was associated with a higher prevalence of periapical symptoms.

Evaluation of an artificial intelligence system for the diagnosis of apical periodontitis on digital panoramic images.

Aims: The aim of the present study was to evaluate the effectiveness of an artificial intelligence (AI) system in the detection of roots with apical periodontitis (AP) on digital panoramic radiographs. Materials and Methods: Three hundred and six panoramic radiographs containing 400 roots with AP (an equal number for both jaws) were used to test the diagnostic performance of an AI system. Panoramic radiographs of the patients were selected with the terms 'apical lesion' and 'apical periodontitis' from the archive and then with the agreement of two oral and maxillofacial radiologists. The radiologists also carried out the grouping and determination of the lesion borders. A deep learning (DL) model was built and the diagnostic performance of the model was evaluated by using recall, precision, and F measure. Results: The recall, precision, and F-measure scores were 0.98, 0.56, and 0.71, respectively. While the number of roots with AP detected correctly in the mandible was 169 of 200 roots, it was only 56 of 200 roots in the maxilla. Only four roots without AP were incorrectly identified as those with AP. Conclusions: The DL method developed for the automatic detection of AP on digital panoramic radiographs showed high recall, precision, and F measure values for the mandible, but low values for the maxilla, especially for the widened periodontal ligament (PL)/uncertain AP.

Endodontic management of maxillary first molar with protostylid: a rare case report.

BACKGROUND: A protostylid is a relatively rare dental developmental aberration characterized as an extra cusp located on the mesial half of the buccal surface of the molars. A protostylid is rarely to be reported due to its low rate of occurrence. This case report describes a patient referred for endodontic treatment due to the presence of a protostylid on the buccal surface of the maxillary first molar that induced apical periodontitis. CASE PRESENTATION: A 53-year-old female reported a 3-month history of pain of chewing with her upper left posterior teeth over 3 months. In the clinical examination, an abraded anomalous cusp-like structure was found on the buccal surface of tooth 26, Cone beam computed tomography (CBCT) revealed a supernumerary cusp with an intact root canal inside, which was fused with the mesiobuccal (MB) root canal in the middle of the root. In addition, extensive periapical radiolucency was observed around tooth 26. The tooth was diagnosed as apical periodontitis, and endodontic treatment was performed. The initial lesion in tooth 26 gradually healed over 1 year of observation. CONCLUSIONS: To our knowledge, this case is the first to describe the endodontic management of a maxillary first molar with a protostylid and advances our understanding of supernumerary cusps. This case provides a reference for the treatment of protostylid.

Management of Apico-marginal Defects With Endodontic Microsurgery and Guided Tissue Regeneration: A Report of Thirteen Cases.

The loss of periodontal tissue support and vertical buccal bone loss in apico-marginal defects can often be mistaken for features indicative of vertical root fractures and this study reports thirteen cases with persistent symptomatic apical periodontitis, apico-marginal defects, and large periapical lesions that were managed with endodontic microsurgery in conjunction with bone grafts and barrier placements with a follow-up period of up to 9 years. At the recall sessions, all cases were asymptomatic with radiographical success with only 2 cases exhibiting residual apical radiolucency, but with evident reduction in the lesion size, indicative of healing. This study highlights the potential of utilizing endodontic microsurgery combined with guided tissue regeneration that proved effective in stimulating the regeneration of periodontal tissue in cases of apico-marginal defects that can lead to favourable long-term outcomes.

Root canal treatment of a six-canal first mandibular molar with extensive periapical lesion: A case report.

RATIONALE: There is an increasing tendency for case reports to reveal anatomical aberrances in mandibular first molars, such as the lateral and accessory canals. Thus, clinicians should pay special attention to anatomic variances when dealing with mandibular first molars requiring endodontic treatment to prevent reinfection within the root canal system, which is responsible for the failure of root canal treatment. PATIENT CONCERNS: This article presents the clinical report and successful root canal treatment of a 24-year-old healthy female patient with an extensive periapical lesion in a 6-canal first mandibular molar. The patient was admitted to the endodontic department because of a periapical abscess found 1 month ago in her left mandibular first molar. DIAGNOSIS: Chronic apical periodontitis was diagnosed based on clinical examination coupled with radiographic and cone-beam computed tomography images. INTERVENTIONS: The treatment plan was to first perform root canal therapy and then perform clinical observation. OUTCOMES: During 1-year follow-up period, the treated tooth was asymptomatic, and complete resolution of the extensive apical lesion was eventually achieved, as shown in the postoperative cone-beam computed tomography images and clinical examination. LESSONS: The present case emphasizes the importance of a comprehensive understanding of root canal morphology, especially rare anatomical variations, to ensure successful root canal treatment. Additionally, the case report adds to the library of previously reported cases of extensive periapical lesions with a direct connection to the root canal system, which demonstrates the potential clinical advantages of root canal therapy as a conservative nonsurgical approach in these cases.

[Comparison of clinical effects of different irrigant solutions combined with different agitation techniques in the treatment of chronic apical periodontitis with fistula].

PURPOSE: To evaluate the effect of combination of auxiliary irrigation technology and root canal irrigation solution in the treatment of chronic apical periodontitis with fistula, and try to seek a more effective and minimally invasive therapeutic strategy. METHODS: One hundred and fifty patients with fistulous chronic apical periodontitis who were diagnosed in Hefei Stomatological Hospital from January 2021 to January 2022 were randomly divided into 6 groups, 25 cases in each group. The 6 groups were as follows, group A: 0.5%NaOCl +ultrasonically activated irrigation; Group B: 1.0%NaOCl+ultrasonically activated irrigation; Group C: 2.0%CHX+ultrasonically activated irrigation; Group D: 0.5%NaOCl+sonic activation; Group E: 1.0%NaOCl+sonic activation; Group F: 2.0%CHX+sonic activation. The fistula healing time, treatment effect and postoperative pain were observed in each group. The data were analyzed with SPSS 20.0 software package. RESULTS: In terms of fistula healing, the 10-day fistula healing rate of group E and group F was higher than that of group A and group D，and the difference was statistically significant(P＜0.05); but there was no significant difference between group E and group F (P＞0.05). The effective rate at 1 month after operation in group A was lower, and the difference was significant (P＜0.05). In terms of postoperative pain, the VAS score of group A was lower than that of group E and group F at all time points, and the difference was statistically significant(P＜0.05). CONCLUSIONS: In the treatment of chronic apical periodontitis with fistula, 1.0% NaOCl or 2.0% CHX combined with ultrasonically activated irrigation or sonic activation obtain a better short-term effect，of which the sonic activation group can also obtain early healing of the fistula, but the incidence of postoperative pain is higher when sonic activation is used.

Resolution of Apical Periodontitis-induced Mental Nerve Paresthesia Through Nonsurgical Endodontic Retreatment: A Case Report.

Paresthesia is a potential consequence of unsuccessful root canal treatment. Persistent infection resulting in apical periodontitis may enlarge sufficiently to involve the mental neurovascular bundle. The case presented in this report was referred for endodontic evaluation with a chief complaint of discomfort on mastication and persistent numbness of the lower left lip. Clinical and radiographic evaluation revealed incomplete primary endodontic treatment of the left mandibular second premolar with complex internal anatomy. The untreated root canal system resulted in the progression of apical periodontitis involving the left mental neurovascular bundle as confirmed by cone-beam computed tomography imaging. Nonsurgical root canal retreatment was performed over 2 visits. At the 3-year follow-up visit, the paresthesia had resolved with return of normal sensation. Nonsurgical endodontic retreatment may be sufficient to allow healing of large periapical lesions and resolve complications including paresthesia without the need for surgical intervention.