Nonsurgical Retreatment Research Articles

Does selective root canal retreatment preserve the tooth’s fracture resistance? An ex-vivo study

ObjectivesTo assess the tooth’s fracture resistance when submitted to a selective root canal retreatment compared to the conventional approach.Methods33 intact permanent mandibular first molars were selected according to specific criteria. After teeth mounting, the primary root canal treatment was conducted and followed by thermo-mechanical aging procedures to mimic a few clinical conditions. The specimens were randomly divided into three groups (n = 11); a control group in which intact teeth were used and two experimental groups according to the retreatment approach: conventional non-surgical retreatment (Conventional-NSR), and selective non-surgical retreatment (Selective-NSR). Later, the teeth were submitted to a final thermo-mechanical aging procedure and tested regarding their fracture resistance (static fracture test). The maximum load to fracture was recorded as were the types of failure modes (repairable or non-repairable fracture). A proper statistical analysis was conducted, considering a significance level of 5%.ResultsThe Conventional-NSR group showed a mean failure load of 867.7 ± 108.9 N while the Selective-NSR group had 1106.8 ± 159.8 N (P = 0.012). Both retreatment groups showed significantly lower results when compared to the control group. Additionally, the Conventional-NSR group showed higher proportions of non-repairable fractures (54.5%) when compared to both the Selective-NSR (36.4%) and control (18.2%) groups.ConclusionsSelective root canal retreatment preserved the tooth’s fracture resistance compared to the conventional retreatment approach.Clinical trial numberNon-applicable. Conducting the current experiment was limited to obtaining approval from the local Research Ethics Committee at the Faculty of Dentistry, Minia University (Committee No. 105, Registration No. 902, Date: 26/3/2024).

Nonsurgical retreatment of anterior teeth with large lateral lesion

Nonsurgical retreatment of anterior teeth with large lateral lesion

Influence of Initial Root Canal Treatment on Intratubular Penetrability and Bond Strength of Nonsurgical Retreatment: An InVitro Study

IntroductionTo assess the effect of combinations of two different endodontic sealers used in initial and endodontic retreatment on the bond strength of the secondary obturation and the penetrability of the sealers. MethodsForty-eight mandibular premolars were used, receiving standardized endodontic access and biomechanical preparation. Twenty-four teeth received AH Plus sealer (AHP) in primary obturation and the others received Bio-C Sealer (BCS). Retreatment protocol was performed with an R50 instrument. The samples were further subdivided into four groups (n = 12) based on the combination of primary/secondary obturation sealers: AHP/AHP; AHP/BCS; BCS/AHP; and BCS/BCS. Four samples from each subgroup received the addition of fluorophores to the sealer for penetrability analysis using laser scanning confocal fluorescence microscopy. The root portion on the 8 push-out samples was sectioned into 6 slices of 1.0 mm. Bond strength (BS) was assessed using a universal testing machine until displacement of the filling mass. Failure pattern was evaluated under a stereomicroscope (20× magnification). BS data were analyzed using two-way analysis of variance followed by Tukey's test (P < .05), and the association between the failure pattern and BS value was assessed using the chi-square test (P < .05). Penetrability was qualitatively evaluated. ResultsThe highest BS values were observed in the AHP/AHP (4.54 ± 1.5 MPa) and BCS/AHP (5.00 ± 1.0 MPa) groups (P < .05), with a higher percentage of adhesive failures to the filling material for all groups. Laser scanning confocal fluorescence microscopy images indicated greater penetrability of AHP compared to BCS, both in initial treatment and retreatment. ConclusionAHP sealer exhibited higher BS and greater penetrability compared to BCS sealer.

Non-surgical retreatment versus papillary preservation flap surgery for residual pockets: A randomized controlled trial with clinical and patient-reported outcomes.

To compare the efficacy of non-surgical re-instrumentation (NSR) and papillary preservation flap (PPF) surgery at single-rooted teeth with residual pockets. Patients with at least a residual pocket depth (PD ≥ 5 mm) after Steps I and II were enrolled and randomly assigned to receive NSR or PPF surgery. The primary outcome was PD reduction, and secondary outcomes were clinical attachment level (CAL) change and patient-reported outcome measures (PROMs). Outcome variables were measured at baseline, 3 and 6 months. The examiner was blinded. Statistical analysis, one site for each patient, included descriptive statistics and analysis of covariance. Forty-six participants were enrolled, and one patient dropped out in the PPF group. After 6 months, both treatments resulted in significant PD reduction (1.3 ± 1.2 mm, p = .009 NSR; 2.0 ± 0.7 mm, p < .001 PPF) and CAL gain (1.0 ± 2.4 mm, p = .031 NSR; 1.4 ± 0.8 mm, p < .001 PPF). PD reduction between groups was not statistically significant (diff: 0.6 mm; 95% confidence interval [CI] [-0.3 to 1.5]; p = .167). Pocket closure was 61% NSR versus 86% PPF (p = .091). Smoking was associated with less PD reduction of almost 1 mm in both treatments. Treatment time was longer for PPF surgery, but PROMs and post-operative pain were similar between groups. Both NSR and PPF reduced PD without significant difference between treatments at 6 months. PPF surgery may offer faster PD reduction, but smoking habits reduce treatment efficacy.

Oral health-related quality of life and perceptions of patients following primary root canal treatment or non-surgical retreatment.

This retrospective cohort study compared the effect of primary root canal treatment (RCT) with root canal retreatment (Re-RCT) on patient-reported outcomes in Kuala Lumpur, Malaysia. Forty randomly selected adults participated (RCT n = 20; Re-RCT n = 20). The impact their dentition had on the Oral Health Impact Profile-14 (OHIP-14) was assessed by calculating the prevalence of oral health impact, and the severity score. Focus group discussions using a semi-structured guide were arranged through an online meeting platform. Qualitative content analysis identified common themes, and relevant quotes gathered. The impact on OHIP-14 was limited for both RCT and Re-RCT groups with no significant differences in the prevalence of oral health impact. Significant differences were found for functional limitation (RCT higher) and psychological discomfort (Re-RCT higher). Common themes from the discussions include the importance of retaining teeth, the significance of effective communication between clinicians and patients and that the respondents were satisfied with the treatment.

Micro-Computed Tomography Analysis of Resin and Calcium Silicate Based Sealers Removal in Mandibular Molars Curved Canals.

The removal of the root canal sealer is an important factor in nonsurgical retreatment. The aim of this study was to compare the removal of AH Plus, Well Root ST, and AH Plus Bioceramic Sealer using Protaper Universal retreatment files. The curved mesio-buccal canals of extracted mandibular molars were prepared with the Protaper Gold file system (up to F2). Specimens were randomly divided into 3 groups and filled with the single cone technique using AH Plus, Well-Root ST, and AH Plus Bioceramic Sealer, respectively. After two weeks, the root canal filling of all specimens was removed using Protaper Universal retreatment files. All specimens were scanned using micro-CT. The remaining volume of the root canal filling was recorded in total and the coronal, middle, and apical third of each specimen. Well-Root ST and AH Plus Bioceramic Sealer groups had a higher percentage of total remaining filling material than the AH Plus group (P<0.05). This study has shown that the volume of remaining root canal filling was significantly higher in the samples filled with calcium silicate-based sealers.

Comparative Evaluation of Solite RS3 and HyFlex Remover Retreatment Files in Conserving Remaining Dentin Thickness During Endodontic Retreatment Using Cone Beam Computed Tomography: An In Vitro Analysis.

Introduction Non-surgical retreatment is seen as a conservative choice for dealing with recurrent infections, instead of opting for periapical surgery. The retreatment processes should be promptly and efficiently carried out, utilizing a suitable armamentarium. The objective of this experiment is to evaluate the quantity of root dentin that remains following the removal of gutta-percha (GP) from the root canal employing two distinct retreatment files. Materials and methods Sixty single-rooted teeth were selected for the examination. The process of shaping and cleaning was performed using the step-back approach, with a master apical file size of 40. The smear layer was effectively eliminated by rinsing with a solution of 3% sodium hypochlorite and 17% ethylenediaminetetraacetic acid. Paper points were employed to desiccate the canals. The obturation process involved the utilization of the lateral compaction technique with the AH Plus sealer (Dentsply Sirona, NC, USA). The teeth were classified into two groups: Group I (n=30) underwent retreatment using HyFlex Remover (Coletene India, Pvt., Ltd.), whereas Group II (n=30) received therapy with Solite RS3 retreatment files (Solite Dental in Chennai, India). The remaining dentin thickness (RDT) was assessed by cone beam computed tomography at levels 3, 6, and 9 mm from the cemento enamel junction after the removal of GP. The acquired data underwent examination using an independent t-test to determine statistical significance. Results The findings demonstrate that the utilization of Solite RS3 files led to a higher level of dentin thickness remaining at 3 mm, 6 mm, and 9 mm on the mesial side in comparison to HyFlex Remover retreatment files. The observed difference was found to be statistically significant at a significance level of p<0.05 on the mesial side. Nevertheless, there was no notable disparity seen between the two file types at these three levels on the distal side (p>0.05). Conclusion Based on the obtained results of the study, it can be concluded that Solite RS3 files show promise in preserving the RDT. However, further studies encompassing diverse parameters are needed to establish a conclusive and definitive conclusion.

Comparative Evaluation of the Efficacy of ProTaper & Mtwo Rotary Retreatment System and Conventional Hand H-files for Removal of Gutta-percha from Root Canal - A Stereomicroscopic Study.

Root canal retreatment aims to eliminate or substantially reduce the microbial load from the root canal and removal of previous root filling materials is the primary goal of nonsurgical retreatment. To comparatively evaluate the effectiveness of ProTaper retreatment files, Mtwo retreatment files, and Hedstrom files along with Gates Glidden (GG) Drill by using a stereomicroscope for the detection of remaining gutta-percha after root canal retreatment using a stereomicroscope. Forty-five test samples were divided into three experimental groups (15 samples each), such as Group A-ProTaper retreatment files; Group B-Mtwo retreatment files; Group C-Hedstrom files along with Gates Glidden Drill. After routine endodontic treatment in the test samples, gutta-percha was removed from the test samples as per the division of different retreatment file systems. Further, test samples were divided longitudinally and were evaluated under the stereomicroscope. Stereomicroscopic images were captured and analysed under Image Analyser Software-Image J. One-way ANOVA test was used for comparison of gutta-percha removal between the groups and Tukey's post hoc test was used for pairwise comparisons. The least remaining filling material was seen in specimens retreated with the ProTaper universal system. The highest remaining filling material was seen in specimens retreated with Hedstrom file with Gates Glidden Drill. All experimental test techniques left gutta-percha remnants within the root canal. ProTaper universal rotary retreatment system proved to be an efficient method of removing gutta-percha and left relatively less volume in comparison with other test systems.

Further Interventions after Root Canal Treatment Are Most Common in Molars and Teeth Restored with Direct Restorations: A 10–11-Year Follow-Up of the Adult Swedish Population

IntroductionThe aims were to investigate 1) the frequency of nonsurgical retreatment, root-end surgery, extraction, and further restorative treatment during a follow-up of 10–11 years after root filling and compare the frequencies according to tooth group and type of coronal restoration and 2) the timing of nonsurgical retreatment, root-end surgery, and extraction. MethodsData were collected from the Swedish Social Insurance Agency's register. A search for treatment codes identified teeth root filled in 2009 and the type of coronal restoration (direct, indirect, and unspecified) registered within 6 months of root filling. The root-filled teeth were followed 10–11 years, and further interventions were recorded. Descriptive statistics and chi-square tests were used for statistical analysis. ResultsIn 2009, root fillings were registered for 215,611 individuals/teeth. Nonsurgical retreatment, root-end surgery, and extraction were undertaken in 3.5%, 1.4%, and 20% teeth, respectively. The frequency of further interventions varied with respect to tooth group and type of coronal restoration, but only slightly for endodontic retreatments. Further interventions, except for root-end surgery, were registered more often for molars and directly restored teeth (P < .001). The majority of endodontic retreatments were undertaken within 4 years, while extractions were evenly distributed over 10–11 years. ConclusionsThe frequency numbers of nonsurgical retreatment and root-end surgery were low, despite 1 in 5 root-filled teeth registered as extracted. Further interventions were most common in molars and directly restored teeth. Endodontic retreatments were performed more often during the first 4 years.

Incidence of Middle Mesial Canals in Mandibular Molars during Root Canal Treatment and Nonsurgical Retreatment

IntroductionLarge-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. MethodsIncluded 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. ResultsIncidence 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. ConclusionsOverall 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.

Comparative evaluation of incidence of dentinal defects after root canal preparation using three different endodontic retreatment systems - An in vitro study.

Safe and efficient removal of all root filling materials from the root canal system without compromising radicular dentin structure is essential for optimal nonsurgical retreatment. The aim of this study was to evaluate and compare the incidence of dentinal defects caused during root canal filling removal using conventional, rotary, and reciprocating retreatment file systems. A detailed protocol explaining purpose and procedures of the study was submitted to the Institutional Ethics Committee and ethical clearance obtained. Sixty human maxillary permanent central incisors were collected and decoronated to 12-mm standardized length. The canals prepared up to a master apical file size F3 with Protaper hand files, obturated using AH plus sealer, examined under the stereomicroscope (×40 magnification): Group I: Control (n = 15), Group II: Conventional (n = 15), Group III: Protaper Universal Retreatment Files (n = 15), and Group IV: Reciproc Blue (n = 15). After instrumentation, teeth were sectioned at 3, 6, and 9 mm from the apex to evaluate the presence of dentinal defects under the stereomicroscope. Statistics were performed using the SPSS, version, 25 (SPSS Inc., Chicago, IL, USA). Initially, normality test was done using the Shapiro-Wilk test and data were not normally distributed followed by Kruskal-Wallis test. P < 0.05 is considered statistically significant. Maximum percentage increase in dentinal defects was observed in Protaper Universal Retreatment Files followed by Conventional method and Reciproc Blue. Significantly Reciproc Blue reduced the incidence of dentinal defects after root canal preparation.

СРАВНИТЕЛЬНЫЙ АНАЛИЗ ЦИТОТОКСИЧНОСТИ СИЛЕРОВ ДЛЯ ПРОВЕДЕНИЯ ПЛОМБИРОВАНИЯ КОРНЕВЫХ КАНАЛОВ (IN VITRO)

Endodontics, being a part of the discipline "Dentistry", includes sections on the study of morphology, physiology and pathology of dental pulp and human periapical tissues, as well as the prevention and treatment of diseases and injuries associated with these tissues. Its scope of application includes the diagnosis and treatment of pain of pulpar and/or periapical origin, vital pulp therapy, regenerative endodontic procedures, non-surgical root canal treatment, surgical or non-surgical re-treatment of teeth with persisting infection and intracanal teeth whitening with discoloration. Ultimately, the main goal is to preserve the natural dentition.&#x0D; Like other dental specialties, endodontics combines two inseparable parts in its practical part: art and science. The art lies in performing technical procedures during root canal treatment. The scientific part includes fundamental and clinical disciplines, studying.&#x0D; Objectives. To study the cytotoxicity of epoxy resin-based silers in laboratory conditions on human cell lines and conduct their comparative analysis.&#x0D; Methodology. The article presents an analysis of the results of in vitro cytotoxicity of silers by assessing cell viability with direct injection of the studied materials into human cell culture.&#x0D; Conclusion. It has been experimentally proven that samples 1 (AH plus, Dentsply Sirona, Germany) and 3 (Epoxidin DUO, TecnoDent, Russia) do not have cytotoxic properties, unlike 2 samples (Sealart, Dentac, Turkey).

Root canal retreatment of root canals filled with "Neo MTA 2" and epoxy resin, using continuous and asymmetric reciprocal rotation systems: In vitro study.

The study aimed to compare the amount of extrusion, the time taken to achieve apical patency and duration for removing filling material during the retreatment of teeth filled with NeoMTA 2® (Avalon Biomed, Houston, TX, USA), a calcium silicate hydraulic cement and AHPlus™ (Denstsply, Konstanz, Germany), a resin-based cement, using continuous rotation and asymmetric reciprocating rotation instruments. 60 monoradicular human teeth were selected and instrumented with Race #35.06 (FKG Dentaire, La Chaux-de-Fonds, Switzerland). The teeth were randomly assigned to two groups based on the cement used for filling (n = 30 each) AHPlus™ and NeoMTA 2®. Both groups were obturated with gutta-percha, using the lateral condensation technique. During non-surgical retreatments, each group was further divided into two subgroups: D-Race (FKG) and Reciproc (VDW, Munich, Germany) (n = 15 each). The total time to achieve apical patency and complete the retreatment were recorded. Extruded debris were collected and weighted. Student t-tests were employed for mean comparisons to assess significant differences between variables. No statistically significant differences were found in terms of type of cement and apical extrusion. Regarding the rotation system, using the Reciproc system resulted in longer time to achieve patency and retreatment times compared to D-Race system, with statistically significant differences (P< 0.05). All systems used in retreatment led to apical extrusion. Apical patency was achieved in all cases. Key words:D-Race, Reciproc, calcium silicate-based cement, root canal retreatment.

Comparative analysis of novel heat-treated retreatment file system on the removal of obturating material using nano-computed tomography.

The aim of nonsurgical retreatment is to remove the previous filling material followed by chemo-mechanical preparation of the canal to achieve proper disinfection of the root canal system. This is then followed by re-obturation. This study evaluates the time taken to retrieve the gutta-percha and the quantity of remaining filling material after retreatment with two different file systems. The quantity of remaining filling material was assessed using nano-computed tomography (CT) due to its increased accuracy. Forty extracted single-rooted teeth were split into two groups at random and decoronated and obturated at a standard root length of 16 mm. Solite RS3 (SRS-3) Retreatment and ProTaper Universal Retreatment (PTUR) systems were used to retrieve the gutta-percha after a preoperative nano-CT scan. Postoperative nano-CT scan was taken and both the scans were superimposed to quantify the remaining filling material. The time taken to remove gutta-percha was measured using a stopwatch. The statistical analysis comparing the two groups was conducted using the independent t-test. The quantitative analysis of remaining filling material using nano-CT showed no statistical difference between both the file systems used (P > 0.05). However, SRS-3 took significantly less time in the removal of gutta-percha (P < 0.05). Hence, we can conclude that there is no significant difference in the amount of remaining filling material between both the file systems. However, time taken to remove the gutta-percha was lesser in SRS-3 compared to PTUR file system.

Risk factors associated with the survival of endodontically treated teeth: A retrospective chart review

BackgroundStudies on risk factors affecting tooth retention after endodontic treatment in dental school settings are limited. Understanding these factors is crucial for preserving teeth. The aim of this retrospective study was to evaluate patient- and tooth-level risk factors associated with the survival of endodontically treated teeth. MethodsElectronic health records of patients who underwent endodontic treatment at the School of Dental Medicine at the University of Pennsylvania from 2017 through 2020 were analyzed. Patient-level factors included age, sex, American Society of Anesthesiologists Physical Status Classification, smoking history, diabetes status, and amoxicillin allergy. Tooth-level factors included position, presence of restorations, and periodontal conditions with preprosthetic treatments. ResultsThe results of this study indicate that the patient-level factors significantly associated with tooth retention included age, sex, American Society of Anesthesiologists Physical Classification Status, and amoxicillin allergy. Tooth-level factors such as core buildup, full-coverage crown, healthy periodontium, and scaling and root planing were also associated with higher survival rates. Mandibular premolars had higher survival rates than mandibular molars. ConclusionsThis investigation revealed that the tooth retention rate of endodontically treated teeth was 96.2% after initial root canal treatment, 92.4% for nonsurgical re-treatment, and 97.8% for surgical re-treatment. Practical ImplicationsThe tooth retention of the endodontic treatment was associated with healthy periodontium, tooth structure, tooth position, tooth restoration, and the patient’s overall health.

Microstructural Evaluation of the Mineralized Apical Barrier Induced by a Calcium Hydroxide Paste Containing Iodoform: A Case Report

IntroductionA 65-year-old man had nonsurgical retreatment using an iodoform and calcium hydroxide paste in a maxillary left canine with persistent apical periodontitis. An apical mineralized barrier (AMB) was observed 3-months postoperatively. Unfortunately, the tooth was extracted due to a cementum tear. This provided an opportunity to analyze the AMB histologically, as there is a lack of previous reports on its microstructure. MethodsAfter extraction and removal of the granulation tissue from the root surface, the canine was processed, and observed using micro–computed tomography (μCT) and light microscopy. Thereafter, the specimen was resin-embedded specimen was evaluated by scanning electron microscopy, micro–X-ray fluorescence spectroscopy and Raman spectroscopy to understand the mechanism and nature of the AMB formation during apical healing. ResultsNonsurgical retreatment was clinically successful based on the absence of clinical symptoms of apical periodontitis and the radiographic presence of an AMB. The AMB was opaque and could be readily differentiated from dentin under a light microscope. Micro–computed tomography analysis revealed that the AMB had the same mineral density as dentin. Scanning electron microscopy revealed that the AMB had two distinct layers based on the size of the calcified particles. Elemental mapping using micro–X-ray fluorescence spectroscopy showed that the localization of calcium and phosphorus differed between AMB and other areas of biomineralization. Raman spectral mapping revealed that the surface layer of the AMB consisted of collagen, calcium carbonate, and hydroxyapatite. ConclusionsThis study explored new analytical methods for elucidating the apical wound-healing process and the nature of the mineralized repair. The findings provided detailed information on the AMB highlighting a bilaminar structure with high calcium components higher on the inside and a brightness similar to cementum not dentin and the presence of hydroxyapatite.

Endodontic retreatment of mandibular molars with the presence of missed middle mesial root canals: An important clinical lesion

Aim: Untreated root canals may have a direct impact on root canal treatment (RCT) outcome. The aim of this case report is to describe the nonsurgical root canal retreatment of two mandibular first molars in a patient's mesial roots that had previously missed middle mesial root canals (MMC). Methodology: A 14-year-old female was referred to the our clinic with the complaint of pain in the posterior areas of the right and left mandibula. During the examination, previous RCTs [teeth 36 (mandibular left first molar) and 46 (mandibular right first molar)] were observed. Besides, these teeth have periradicular lesions in the mesial roots probably due to unsuccessful previous treatment. Nonsurgical retreatment was suggested and accepted. Access cavities were prepared and the unnoticed MMCs were detected at the isthmus connecting both mesiobuccal and mesiolingual canals. All the root canals were shaped with NiTi rotary endodontic files. During the shaping, the root canals were irrigated copiously with NaOCl, EDTA, clorhexidine, and saline solutions under a certain protocol. Calcium hydroxide was used for intracanal dressing. Gutta-percha and a resin-based root canal sealer were used for filling. Coronal restorations of the teeth were completed with a composite resin. Conclusion: At follow-up examinations after 3-, 6-, and 12-months, the teeth were asymptomatic and radiographically showed repair of the lesion. Healing was achieved without any need for further endodontic surgical intervention. How to cite this article: Başoğlu A, Harorlı H, Er K. Endodontic retreatment of mandibular molars with the presence of missed middle mesial root canals: an important clinical lesion. Int Dent Res 2023;13(2):99-103. https://doi.org/10.5577/idr.2023.vol13.no2.8 Linguistic Revision: The English in this manuscript has been checked by at least two professional editors, both native speakers of English.

The Effect of Unintentional AH-Plus Sealer Extrusion on Resolution of Apical Periodontitis After Root Canal Treatment and Retreatment—A Retrospective Case-control Study

IntroductionThis 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. MethodsIn 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. ResultsA 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. ConclusionsUnintentional 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.

Flare-ups After Nonsurgical Retreatments: Incidence, Associated Factors, and Prediction

IntroductionThe aims of this study were to determine the incidence, associated factors, and predictability of flare-ups after nonsurgical retreatments (NSRetx). MethodsAll 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. ResultsIncidence 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). ConclusionsIncidence 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.

Treatment outcome of surgical and non-surgical endodontic retreatment of teeth with apical periodontitis.

To evaluate and compare the treatment outcome of root filled teeth with apical periodontitis treated either non-surgically or by endodontic microsurgery, and to assess the influence of an intra-radicular post, clinical and demographic factors. Clinical and radiological data from 1157 patients with apical periodontitis in previously root filled teeth treated by postgraduate students at the Department of Endodontics, University of Oslo, between September 2010 and January 2020 with recall data at least 11 months from completion were studied. Surgical cases were scored using the Rud/Molven criteria and grouped into success, uncertain or failure at control. Non-surgical cases were scored with the periapical index (PAI) and similarly grouped into success, uncertain or failure at control. Chi-square analyses were used for comparison of subgroups of teeth treated and logistic regression analyses for assessment of the influence of clinical variables. Non-surgical retreatment was performed on 351 teeth and 107 teeth were treated with endodontic microsurgery, with overall success rates of 65.5% and 77.6%, respectively. The difference was statistically significant. Teeth with an intra-radicular post treated non-surgically (n = 30) were successful in 73.3% of cases, whereas teeth with intra-radicular post treated with endodontic microsurgery (n = 30) had a lower, 66.7% success rate. The distribution of tooth groups (anterior, premolar and molar) differed significantly between surgical and non-surgical cases, with maxillary anterior and premolar teeth more often treated surgically. Non-surgical retreatment cases were significantly influenced by patients' age (older patients had poorer outcome) and pre-operative PAI score (negatively correlated with outcome). Surgical cases were not significantly influenced by the factors studied here. The tooth type differed significantly for teeth treated by surgical versus non-surgical methods. Microsurgical treatment with apicectomy and retrograde filling showed significantly better treatment results than non-surgical retreatment of teeth with apical periodontitis, whereas treatment outcome in teeth with posts after non-surgical treatment tended to be better than after surgical treatment. Outcome of non-surgical retreatment was negatively influenced by older age and higher pre-operative PAI score.