The current case report aims to document a rare presentation of a distant odontogenic lesion of a 35-year-old male patient with mild clinical discomfort in the mandibular right first molar; exploring the diagnostic and therapeutic intricacies of an uncommon distant endodontic pathosis ultimately resolved through meticulous nonsurgical retreatment. Despite a normal oral examination, diagnostic radiography revealed a suboptimal root canal treatment and apical lesions surrounding mesial- and distal-root apices; including a distinct radiolucency beneath the apex of the second mandibular molar discovered through panoramic radiography, and confirmed via cone-beam computed tomography. In addition, the computed tomography disclosed a previously unreported and unusually large endodontic lesion that extended toward the mandibular canal; highlighting a necessity for the continued exploration of a unique endodontic presentation. A nonsurgical endodontic retreatment led to a remarkable reduction in the radiolucent lesions within one year; emphasizing the significance of comprehensive diagnostic approaches and individualized treatments.

BACKGROUND: Large-scale clinical studies on the incidence of middle mesial canals (MMCs) in nonsurgical root canal treatment (RCT) and retreatment of mandibular molars are lacking. The primary aim of this observational study was to determine the incidence of MMCs in mandibular first and second molars that received RCT or nonsurgical retreatment (NSRetx). The secondary aim was to determine factors associated with incidence of MMCs.
METHODS: Included were 3018 mandibular molars that received RCT (n = 1624) or NSRetx (n = 1394) by 3 endodontists in a private practice. Demographic and procedural data were collected. Bivariate and multivariable (Poisson regression model) analyses were performed.
RESULTS: Incidence of MMCs was 8.8% (n = 267). Although the bivariate analysis showed that NSRetx was significantly associated with incidence of MMCs, this association did not reach the threshold for statistical significance after controlling for all covariates (P = .07). Multivariable analysis on the entire cohort showed that incidence of MMCs was significantly associated with younger age (risk ratio [RR] = 1.62; 95% confidence interval [CI], 1.28-2.06), male gender (RR = 1.48; 95% CI, 1.18-1.85), preoperative cone-beam computed tomography (CBCT) (RR = 1.48; 95% CI, 1.17-1.89), and first molar (RR = 2.30; 95% CI:1.74-3.05). Subgroup multivariable analyses revealed that incidence of MMCs was associated with male gender only in the RCT group (RR = 2.26; 95% CI, 1.55-3.30) but not in the NSRetx group (RR = 1.11; 95% CI, 0.82, 1.50); and with preoperative CBCT only in the NSRetx group (RR = 1.78; 95% CI, 1.28, 2.50) but not in the RCT group (RR = 1.10; 95% CI, 0.71, 1.69). Associations with younger age and first molar remained unchanged.
CONCLUSIONS: Overall incidence of MMCs was 8.8%. Incidence of MMCs was significantly higher in younger patients and in mandibular first molars but was not associated with the type of treatment.

UNASSIGNED: Retention of the natural tooth without any symptoms in the oral cavity is one of the prime desires of endodontic treatment. Root canal therapy usually leads to failure when treatment is not up to the mark of acceptable standards. To address these deficiencies, non-surgical endodontic retreatment is the most accepted option with the success rate ranging from 65% to 83%. Forty-five single-rooted mandibular premolars with undeviated canals (as per Schneider\'s criteria) were obtained and divided further into three groups with 15 specimens along with resin-based sealer solvent in each group: Group 1 - Retreatment rotary file system, Group 2 - Ultrasonics, and Group 3 - Diode laser. Specimens were then evaluated under a stereomicroscope at ×10 after cutting in two halves followed by evaluation of the remaining filling material using Hulsmann and Bluhm criteria.
UNASSIGNED: Nonsurgical retreatment.
UNASSIGNED: The aim of the study was to evaluate and compare the efficacy of various retreatment techniques for the elimination of root canal filling material.
UNASSIGNED: The sample size was determined using the formula n = (Zα/2)2 s2/d2. The design of the study is in vitro experimental study.
UNASSIGNED: A sum of 45 single-rooted extracted human permanent mandibular premolars were included in this study. All teeth were biomechanically prepared and obturated followed by decoronating the samples. All specimens were randomly divided into 3 groups comprising 15 specimens along with solvent based on the technique for the filling material elimination from the root canal, i.e. Group I: retreatment rotary files, Group II: ultrasonics, and Group III: diode laser.
UNASSIGNED: The Tukey\'s post hoc tests and one-way analysis of variance were used for comparison of the study parameters among the groups.
UNASSIGNED: Results revealed that ultrasonics showed the least amount of remaining filling material within the root canal which had a significant difference from other groups, i.e. retreatment rotary files and diode laser.
UNASSIGNED: Ultrasonics with a resin-based sealer solvent can be considered a preferred option for nonsurgical retreatment. However, none of the groups shows complete elimination of filling material inside the root canal system.

BACKGROUND: This study aimed to investigate the effect of unintentional AH Plus sealer extrusion on the outcome of nonsurgical root canal treatment and retreatment in teeth with apical periodontitis (AP) compared to teeth with AP and no sealer extrusion at the 1-year follow-up.
METHODS: In a retrospective case-control study conducted from September 2016 to September 2021, teeth presenting clinical and radiographic signs of AP prior to treatment were included. The study comprised 2 groups: AH Plus sealer extrusion group (n = 60): initial root canal treatment or nonsurgical retreatment with unintentional apical extrusion of AH Plus sealer; and no AH Plus sealer extrusion group (n = 60): underwent the same treatment types without sealer extrusion. Additional factors, including sex, age, tooth type, tooth location, and treatment type, were recorded as potential outcome predictors. At 1-year follow-up, teeth were evaluated clinically and radiographically, and outcomes were classified as favorable (healed/healing) or unfavorable (uncertain/non-healing). Statistical analyses, such as the χ2 test, logistic regression, and Mann-Whitney U test, were employed for data analysis.
RESULTS: A favorable outcome was observed in 88.4% and 85% of the cases of the AH Plus sealer extrusion and no AH Plus sealer extrusion groups, respectively. There was no statistically significant difference between the groups in terms of outcomes (P > .05) when analyzed categorically or ordinally. Of independent variables, nonsurgical retreatment showed lower healing of AP in both groups.
CONCLUSIONS: Unintentional AH Plus sealer extrusion did not affect the healing of AP. However, initial root canal treatment showed better healing of AP than nonsurgical retreatment in the presence of AH Plus sealer extrusion. The analyzed outcome predictors had no effect on treatment outcome.

BACKGROUND: The aims of this study were to determine the incidence, associated factors, and predictability of flare-ups after nonsurgical retreatments (NSRetx).
METHODS: All patients (n = 3,666) who received NSRetx by 3 endodontists in 2 endodontic offices during a period of 6 years (2016-2022) were included. Demographic, diagnostic, and procedural data were collected. A flare-up was defined as moderate-severe pain with/without swelling that took place within 14 days of initiation of NSRetx and resulted in an unscheduled appointment. Bivariate analyses on the entire cohort and multivariable analyses on cases with complete dataset (n = 2,846) were performed to identify significant associations. A Random Forest algorithm was used to make a prediction model.
RESULTS: Incidence of flare-ups was 3.95% (n = 145). Increased risk of flare-ups was associated with diabetes (adjusted odds ratio [AOR] = 2.01; 95% confidence interval [CI], 1.01-3.97), mandibular teeth (AOR = 1.67; 95% CI, 1.11-2.52), moderate-severe preoperative pain on percussion (AOR = 2.13; 95% CI, 1.31-3.50), and pain on palpation (AOR = 1.63; 95% CI, 1.01-2.64). Lower risk of flare-up was associated with high blood pressure (AOR = 0.44; 95% CI, 0.21-0.82) (P < .05). The prediction model was not able to predict flare-ups with sufficient confidence (precision = 0.13).
CONCLUSIONS: Incidence of flare-ups following NSRetx was low (∼4%) and had a weak but significant association with the history of diabetes. Moderate-severe pain on percussion, pain on palpation (any intensity), and mandibular teeth had a significant association with flare-ups. The history of high blood pressure was associated with lower risk of flare-ups. Flare-ups were difficult to predict in this clinical setting.

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.

OBJECTIVE: Selective root canal retreatment is when the treatment is limited to root(s) with radiographic evidence of periapical pathosis. The goals of this retrospective study were as follows: (i) evaluate the clinical and radiographic (periapical radiographs [PR] or cone-beam computerized tomographs [CBCT]) outcome of selective root canal retreatment after ≥12 months follow-up; (ii) evaluate the periapical status of the unretreated roots; and (iii) assess tooth survival.
METHODS: A retrospective study (January 2018 to April 2021) was conducted to identify permanent multirooted teeth that underwent selective root canal retreatment. Clinical records, PR and CBCT were examined to ascertain variables of interest. Outcomes (per root and per tooth) were classified into \'favourable\' or \'unfavourable\' using well-established clinical and radiographic healing criteria. Treatment outcomes for the whole tooth and per root were compared as well as bivariate associations between the treatment outcome of the retreated roots and the treatment-related parameters (quality of root filling, sealer extrusion, iatrogenic mishaps and type of restoration) were analysed using Fisher\'s exact test (α = .05). Survival was recorded in months.
RESULTS: A total of 75 teeth (195 roots) in 75 subjects were available for outcome analysis. The favourable outcome per tooth was 86.7%. At follow-up, 92.6% of the retreated roots had a favourable outcome. From the unretreated roots, 3.5% showed radiographic signs of an emerging periapical lesion. No statistical difference was shown between the outcomes per root and per tooth between both groups. None of the treatment-related parameters had a direct influence on the outcome of the retreated roots. The survival rate at 12-48 months after retreatment was 91.5%.
CONCLUSIONS: Selective root canal retreatment is associated with a favourable outcome in a majority of cases. Unretreated roots rarely developed radiographic signs of a new periapical lesion at follow-up. Future high-quality clinical trials with larger sample sizes and longer follow-up periods are required to confirm these findings.

BACKGROUND: The decision of which modality of secondary endodontic treatment to perform is multifactorial and clinician dependent. The literature surrounding the long-term survival of nonsurgical retreatment compared with surgical retreatment remains equivocal and warrants further investigation. This 7-year retrospective study seeks to compare the outcome of nonsurgical retreatments with that of root-end surgeries performed on teeth without prior nonsurgical retreatments.
METHODS: Insurance claims from 1021 teeth of 987 patients in the Delta Dental of Wisconsin database were analyzed from the years 2008-2017. Tooth survival was evaluated using Cox regression models, and the P value was set at .05. Survival time was considered from the time of completion of nonsurgical retreatment or root-end surgery to the time of an untoward event, which was defined as extraction after root-end surgery or extraction/root-end surgery after nonsurgical retreatment. Only procedures performed by endodontists were included in the analysis.
RESULTS: The survival rate of teeth that received nonsurgical retreatment was 90% after 2 years, 86.8% after 4 years, and 85% after 6 years. The survival rate of teeth that received root-end surgery was 93.7% after 2 years, 90.5% after 4 years, and 88% after 6 years. No statistically significant difference was found in the survival of nonsurgical retreatment compared with root-end surgery. Likewise, no statistically significant difference was found within or between tooth types (anterior, premolar, or molar) when comparing nonsurgical retreatment with root-end surgery.
CONCLUSIONS: The results of this study indicate that clinicians can choose either nonsurgical retreatment or root-end surgery after failed primary root canal therapy. Tooth location was not a determining factor in the survival rate after nonsurgical retreatment or root-end surgery.

The complexity of the nonsurgical endodontic retreatment should be weighed against the benefit of surgical approach. This case report describes uncommon diagnosis and successful nonsurgical endodontic management of mandibular first premolar with a previous history of failed apicoectomy and incomplete root-end resection using mineral trioxide aggregate and cone-beam computed tomography.

BACKGROUND: The aim of this study was to investigate changes in treatment planning decisions among different practitioner groups over 7 years for teeth with apical periodontitis and a history of endodontic treatment.
METHODS: A Web-based survey was sent to dentists in Pennsylvania in 2009 consisting of 14 cases with nonhealing periapical lesions and intact restorations without evidence of recurrent caries. Participants selected among 5 treatment options: wait and observe, nonsurgical retreatment (NSRTX), surgical retreatment (SRTX), extraction and fixed partial denture, or extraction and implant (EXIMP). In 2016, the identical survey was resent to the original 2009 participants.
RESULTS: In 2009, 262 dentists participated in the survey. Two hundred one participants were general practitioners (GPs: 76.7%), 26 endodontists (ENDOs: 9.9%), and 35 other specialists (prosthodontics, periodontics, and oral surgery [SPECs]: 13.4%) (n = 262). EXIMP, NSRTX, and SRTX were fairly equally selected but with great variation between practitioner groups (χ2 = 173.49, P < .05). A subset group of 104 participants (SUB) (39.7% of the original participants) retook the survey in 2016 (69 GPs [66.3%], 15 ENDOs [14.0%], and 20 SPECs [19.7%]). Comparisons among practitioner groups were significantly different in SUB (n = 104) for 2009 (χ2 = 95.536, P < .05) and 2016 (χ2 = 109.8889, P < .05). Intragroup reliability between 2009 and 2016 revealed no significant differences between the overall treatment planning choices for all practitioners (GPs, ENDOs, or SPECs). Intrapractitioner reliability showed many treatment planning decision changes on an individual level. Chances that individuals changed their original decision were 47.8% (95% confidence interval, 45.2%-50.4%) and were significantly different among the 3 practitioner groups (GPs > SPECs > ENDOs [χ2 = 11.2792, P < .05]). No significant changes were observed in the decision for tooth saving versus replacement treatment options (P = .520).
CONCLUSIONS: No significant differences were noted between current and past treatment planning decisions in regard to tooth preservation by endodontic retreatment versus tooth extraction and replacement. However, individual practitioners lacked consistency in their decision making over time.