Prevalence of Drug Resistance Associated Substitutions in Persons With Chronic Hepatitis C Infection and Virological Failure Following Initial or Re-treatment With Pan-genotypic Direct-Acting Antivirals: A Systematic Review and Meta-analysis.

BACKGROUND: The advent of short-course, curative treatment with direct-acting antivirals (DAA) has given promise for the global elimination of hepatitis C virus (HCV) infections by 2030. Virological failure occurs in 2%-12% of persons receiving curative DAA treatment and may be presaged by pre-existing polymorphisms or result from selection of drug resistant variants during therapy. METHODS: We conducted a systematic review to assess the prevalence of HCV resistance associated substitutions (RAS) among individuals with chronic hepatitis C infection who had virological failure following initial or re-treatment with pan-genotypic DAA regimens. We included 34 and 22 studies assessing RAS in people with virological failure published between January 2014 and July 2023. Pooled RAS prevalence was estimated using random-effects meta-analysis. RESULTS: The pooled prevalence of RAS in people with virological failure following initial DAA treatment was 78.0% (95% confidence interval [CI]: 62.0-92.0) for sofosbuvir/velpatasvir, 81.0% (95% CI: 67.0-93.0) for sofosbuvir/daclatasvir, and 79.0% (95% CI: 70.0-87.0) for glecaprevir/pibrentasvir, with a high prevalence of resistance to the NS5A inhibitors. Among those with virological failure following re-treatment regimens, RAS were present in 93.0% (95% CI: 83.0-99.0) for sofosbuvir/velpatasvir/voxilepravir and in 100% (95% CI: 92.0-100) for glecaprevir/pibrentasvir, with resistance driven by RAS to NS5A inhibitors. DISCUSSION: At least 1 RAS is present in a high proportion of the few individuals with virological failure following initial or re-treatment with pan-genotypic DAA regimens. There is a need for ongoing surveillance for DAA-associated resistance, to assess risk factors for their development and clinical impact to inform best practice strategies for re-treatment.

Does size matter? A single institution's comparison of Aquablation in prostates greater than or less than 150 mL.

BACKGROUND: Surgical management options for lower urinary tract symptoms due to benign prostatic hypertension have remained limited in prostates of large volume. The advent of the Aquablation has created a potential minimally invasive option for treatment in prostates of all volumes. Thus, this study aims to evaluate outcomes and complications of Aquablation in clinical practice based on prostate volume. METHODS: Collected variables included adverse events with Clavien-Dindo classifications, transfusion rates, surgical retreatment rates, continued medication use postoperatively, and International Prostate Symptom Score (IPSS) with Quality-of-Life indicator. Aquablations were stratified by preoperative prostate volume. RESULTS: One hundred seventy-four men were included in the study. The average postop decrease in IPSS was 10.28, with a 2.02 point decrease in Quality-of-Life at 1 year. Postop increase in peak urinary flow rate was 7.65 mL/s for an average of 16.44 mL/s. Hemoglobin drop average was 1.78 g/dL, but only 2.3% of patients required a transfusion. 12.9% of patients required surgical retreatment. Six months after Aquablation, 22.9% and 12.9% of patients continued taking Alpha-blockers and Androgen receptor inhibitors, respectively. Adverse events occurred in 33 patients (19.0%). Eighteen patients were excluded from secondary analysis due to unrecorded prostate volume, leaving 123 with volumes <150 mL and 33 with volumes ≥150 mL. Groups were comparable with respect to length of stay, adverse events, blood transfusion, IPSS with Quality-of-Life indicator preoperative and postoperative, postop peak urinary flow, and postop alpha-blocker use. Larger prostates had a higher rate of adverse events, retreatment, postop hemoglobin drop, and postop use of finasteride. CONCLUSIONS: Aquablation is a viable treatment option for benign prostatic hyperplasia. Efficacy, safety, subjective outcomes, and adverse event rates were not impacted by prostate volume. However, size does matter as prostates ≥150 mL had higher surgical retreatment rates and postop finasteride use.

Continuation of same programmed death-1 inhibitor regime beyond progression is a novel option for advanced gastric cancer.

BACKGROUND: Gastric cancer is a significant global malignancy with poor prognosis. Although the emergence of immune checkpoint inhibitors (ICIs) prolonged the duration of survival, resistance and progression are inevitable. We aim to evaluate the effectiveness of programmed death-1 (PD-1) inhibitors in immunotherapy beyond progression (IBP). METHOD: We divided the advanced gastric cancer patients who received two lines immunotherapy into same regimen group (with same PD-1 inhibitor regime after IBP) and different regimen group (with different PD-1 inhibitor regime after IBP). Statistical analysis conducted to compare patient characteristics and evaluate survival differences between groups. RESULT: The clinical outcome analysis showed that the same PD-1 inhibitor regime seemed to exhibit a higher disease control rate (DCR) (51.8% vs. 29.2%, P = 0.062), significantly prolonged progression-free survival 2 (PFS2) (162 vs. 75 days, P = 0.001) and overall survival (OS) (312 vs. 166 days, P = 0.022) when compared with those of cross line. In the multivariate analysis, when using different regimen group as reference, the same regimen group was found to be independently associated with improved PFS2 [hazard ratio (HR) = 0.467, 95% confidence interval (CI): 0.267-0.816, P = 0.008] and OS (HR = 0.508, 95%CI: 0.278-0.927, P = 0.027). CONCLUSION: Continuation of the same type of PD-1 inhibitor regime in IBP shows clinical benefits and represents a promising therapeutic approach.

Response to daratumumab-retreatment in patients with multiple myeloma.

Daratumumab is an effective therapy in multiple myeloma (MM). We assessed whether daratumumab retreatment may re-induce significant responses and which patients do benefit the most. We hypothesized, that there is effective synergism between daratumumab and alternating antimyeloma drug combinations during retreatment and that retreatment is safe and effective. Here, we analyzed 293 consecutive MM patients receiving daratumumab at our institution from 2016 until 2023 retrospectively, and compared responses, side effects and survival of the first daratumumab treatment line and its retreatment. We identified 22/293 (8%) patients with daratumumab retreatment. These patients showed an advanced age and ISS/R-ISS stages, and ≥ 3 lines of prior antimyeloma therapy in 91%. Of note, the median durations of the first and subsequent daratumumab treatment were similarly long. We confirmed a therapy break between daratumumab lines as advantageous. Daratumumab retreatment was effective, with responses declining only gradually from its first use to subsequent first and second retreatment with 64%, 46% and 43%, respectively. Interestingly, comparable progression free survival rates were observed with 11.5, 12 months and not reached, respectively. Consistently, adverse events per daratumumab line did not increase. Our findings suggest that well-selected daratumumab-exposed MM patients may show rewarding responses to daratumumab retreatment, the more with alternating antimyeloma combinations, initial good response and CD38-antibody-treatment pauses, thereby proving CD38-antibody-retreatment as feasible, effective and non-toxic. Confirmatory studies are required to further validate our results.

Successful rechallenge with azacytidine and venetoclax after sustained treatment-free remission in a relapsed acute myeloid leukemia patient: a case report.

Combined therapy with venetoclax and hypomethylating agents has significantly improved the outcome of unfit patients ineligible for intensive chemotherapy. A recently published exploratory analysis of the VIALE-A trial reported that up to 51% of patients achieving remission survived more than 2 years. These data along with those from reallife settings, lead to questioning how long it is appropriate to continue treatment in long-term survivors. Accordingly, recent retrospective studies suggested the feasibility of suspending therapy in selected patients while maintaining prolonged responses. Also, these studies showed that retreatment may induce a second remission in almost a third of patients. We report the case of a patient who received salvage therapy with venetoclax and azacytidine, that was discontinued few cycles after blasts clearance because of severe hematological toxicity. Despite suspension, he maintained a sustained response lasting almost one year and was successfully retreated with the same combination when a second relapse occurred.

Salvage holmium laser enucleation of the prostate after previous interventions: a systematic review.

OBJECTIVE: To investigate the feasibility, safety and efficacy of holmium laser enucleation of the prostate (HoLEP) in the re-treatment setting (salvage HoLEP) and compare it to the primary HoLEP procedure that is commonly used for the treatment of benign prostate hyperplasia (BPH). MATERIALS AND METHODS: Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement, PubMed, Scopus, and Cochrane databases were systematically screened, from inception to 8 August 2022. Other potentially eligible studies were retrieved using the reference lists of the included studies. Retrospective and prospective studies, both comparative and non-comparative, were included. RESULTS: A total of 12 studies met the inclusion criteria and were included in the final qualitative synthesis. One study was prospective comparative (non-randomised), seven studies were retrospective comparative, and four studies were retrospective non-comparative or case series. In total, 831 patients were treated with salvage HoLEP in the above studies. Previous intervention before salvage HoLEP ranged among studies. The most commonly performed was transurethral resection of the prostate. Intraoperative parameters of salvage HoLEP were comparable with those reported during primary HoLEP, while all postoperative outcomes were significantly improved after salvage HoLEP and were similar with those observed after primary HoLEP. No major complications were noted after salvage HoLEP according to Clavien-Dindo classification. CONCLUSIONS: Salvage HoLEP after previous interventions for treating recurrent or residual BPH is a feasible, safe, and efficient procedure. Data presented in selected studies, along with the holmium laser's physical properties to resect more tissue and to dissect along the true anatomical plane of BPH, render HoLEP an ideal salvage treatment modality for recurrent or residual BPH symptoms.

Effectiveness and safety of upadacitinib retreatment after withdrawal in moderate-to-severe atopic dermatitis: a retrospective study.

BACKGROUND: Upadacitinib, a janus kinase 1 (JAK1) inhibitor, is effective for moderate-to-severe atopic dermatitis (AD). Upadacitinib treatment may be discontinued in some patients, however, the effectiveness and safety of retreatment after its withdrawal have not been precisely examined in real-world practice. OBJECTIVES: To evaluate the effectiveness and safety of upadacitinib retreatment after withdrawal in real-world clinical practice for Japanese AD patients. METHODS: This retrospective study included 62 Japanese patients with moderate-to-severe AD treated with upadacitinib 15 mg (n = 38) or 30 mg (n = 24). Effectiveness was assessed using eczema area severity index (EASI) and peak pruritus numerical rating scale (PP-NRS) before treatment (baseline), at time-periods of discontinuation, retreatment, and week 12 after retreatment of upadacitinib. Safety was evaluated through the incidence of treatment-emergent adverse events (TEAE). RESULTS: EASI and PP-NRS scores significantly decreased at week 12 after retreatment of upadacitinib compared to baseline in both 15 mg and 30 mg groups. Achievement rates of EASI 75, EASI 90, and EASI 100 at week 12 after retreatment were 83.8%, 56.8%, and 18.9% in 15 mg group, and 87.0%, 56.5%, and 17.4% in 30 mg group, respectively. TEAEs were mild or moderate, and no serious adverse events or deaths were reported. CONCLUSIONS: Retreatment of upadacitinib after withdrawal effectively improved clinical signs and pruritus in patients with AD, with a manageable safety profile, supporting its use for long-term management of AD.

Treat-to-target vs fixed interval retreatment strategy with rituximab in rheumatoid arthritis: a retrospective cohort study.

To compare the effectiveness of retreatment of rheumatoid arthritis (RA) patients with rituximab (RTX) following the treat-to-target retreatment (TTr) or fixed interval retreatment (FIr) strategy. RA patients starting RTX treatment between January 2008 and June 2016, and receiving at least three infusion cycles were grouped by strategy (TTr, FIr or both). Primary outcome (between strategy difference in DAS28-CRP (Disease Activity Score in 28 joints calculated with C-reactive protein)) and secondary outcomes (flares, use of co-medication and mean yearly dose of RTX) were analyzed by group using linear mixed models to account for different strategies within patients. A total of 213 patients, 59 TTr (of whom 32 switched from TTr to FIr) and 186 FIr were included. No between-group difference in mean DAS28-CRP was found (0.10 DAS28-CRP point (95% CI - 0.07 to 0.26)). The TTr strategy did not result in more flares (IRR 1.13, 95%CI 0.87 to 1.47), conventional synthetic disease-modifying antirheumatic drug use (difference - 11.7%, 95%CI - 26.3% to 2.9%), or lower mean yearly RTX dose (difference 172 mg/yr, 95%CI - 355 to 11.7 mg/yr). RTX retreatment with either a TTr or FIr strategy does not seem to lead to better disease control and/or less drug use when used in a DAS28-CRP treat-to-target context. Choice of either strategy can, therefore, be made based on patient and physician preferences and logistical context.

Silicosis predicts drug resistance and retreatment among tuberculosis patients in India: a secondary data analysis from Khambhat, Gujarat (2006-2022).

BACKGROUND: India, with the highest global burden of tuberculosis (TB) and drug-resistant TB, aims to eliminate TB by 2025. Yet, limited evidence exists on drug resistance patterns and retreatment among patients with silico-tuberculosis. This study explores these patterns and assesses the impact of silicosis on TB retreatment in India. METHODS: This secondary data analysis stems from a larger retrospective cohort study conducted in Khambhat, Gujarat, between January 2006 and February 2022. It included 138 patients with silico-tuberculosis and 2,610 TB patients without silicosis. Data from the Nikshay TB information portal were linked with silicosis diagnosis reports from the Pneumoconiosis Board using the unique Nikshay ID as the linking variable. Drug-resistant TB was defined as resistance to any anti-TB drug recorded in Nikshay. Retreatment refers to TB patients who have previously undergone anti-TB treatment for one month or more and need further treatment. Recurrent TB denotes patients who were previously declared cured or had completed treatment but later tested positive for microbiologically confirmed TB. Multivariable logistic regression was used to determine the impact of co-prevalent silicosis on drug resistance and retreatment. RESULTS: Patients with silico-tuberculosis showed a higher proportion of retreatment compared to those without silicosis (55% vs. 23%, p < 0.001). Notably, 28% of patients with silico-tuberculosis were recurrent TB cases, compared to 11% among those without silicosis. Regarding drug resistance, the silico-tuberculosis group exhibited a higher rate (6% vs. 3%), largely due to rifampicin resistance (5% vs. 2%, p = 0.022). Co-prevalent silicosis was associated with a 2.5 times greater risk of drug-resistant TB (adjusted OR 2.5, 95% CI, 1.1-5.3; p = 0.021). Additionally, patients with silico-tuberculosis had a fourfold increased risk of retreatment for TB (adjusted OR 4, 95% CI, 3-6; p < 0.001). CONCLUSIONS: Co-prevalent silicosis significantly elevates the risk of drug resistance, recurrence, and retreatment among TB patients in India. This study indicates a need for improved treatment protocols and suggests that future research should focus on randomized controlled trials to evaluate appropriate anti-TB regimen and duration of therapy for this high-risk group. Given India's goal to eliminate TB by 2025, addressing the challenges posed by silico-tuberculosis is critical.

Fertility-sparing re-treatment for endometrial cancer and atypical endometrial hyperplasia patients with progestin-resistance: a retrospective analysis of 61 cases.

OBJECTIVE: This study aimed to evaluate the oncological and reproductive outcomes of fertility-preserving re-treatment in progestin-resistant endometrial carcinoma (EC) and atypical endometrial hyperplasia (AEH) women who desire to maintain their fertility. METHODS: Our study included 61 progestin-resistant EC/AEH patients. These patients underwent treatment with gonadotropin-releasing hormone agonist (GnRHa) solely or a combination of GnRHa with levonorgestrel-releasing intrauterine system (LNG-IUD) or aromatase inhibitor (AI). Histological evaluations were performed every 3-4 months. Upon achieving complete remission (CR), we recommended maintenance treatments including LNG-IUD, cyclical oral contraceptives, or low-dose cyclic progestin until they began attempting conception. Regular follow-up was conducted for all patients. The chi-square method was utilized to compare oncological and fertility outcomes, while the Cox proportional hazards regression analysis helped identify risk factors for CR, recurrence, and pregnancy. RESULTS: Overall, 55 (90.2%) patients achieved CR, including 90.9% of AEH patients and 89.7% of EC patients. The median re-treatment time was 6 months (ranging from 3 to 12 months). The CR rate for GnRHa alone, GnRHa + LNG-IUD and GnRHa + AI were 80.0%, 91.7% and 93.3%, respectively. After a median follow-up period of 36 months (ranging from 3 to 96 months), 19 women (34.5%) experienced recurrence, 40.0% in AEH and 31.4% in EC patients, with the median recurrence time of 23 months (ranging from 6 to 77 months). Among the patients who achieved CR, 39 expressed a desire to conceive, 20 (51.3%) became pregnant, 11 (28.2%) had successfully deliveries, 1 (5.1%) was still pregnant, while 8 (20.5%) suffered miscarriages. CONCLUSION: GnRHa-based fertility-sparing treatment exhibited promising oncological and reproductive outcomes for progestin-resistant patients. Future larger multi-institutional studies are necessary to confirm these findings.

Evaluation of micro-remnant niduses of arteriovenous malformations post-gamma knife radiosurgery by 3D-rotational angiography.

PURPOSE: Recent innovations in radiological imaging have enabled the detection of micro-remnant niduses of arteriovenous malformations (AVMs) after gamma knife radiosurgery (GKS), which have not been previously perceptible. Herein, we focus on the difficulty of evaluating micro-remnant AVMs after GKS that are hardly perceptible on conventional examinations and propose integrating follow-up three-dimensional rotational angiography (3D-RA) in the previous gamma plan as a solution. METHODS: We retrospectively searched NTT Medical Center Tokyo hospital database for patients with AVMs who underwent both two-dimensional digital subtraction angiography (2D-DSA) and 3D-RA as follow-up for GKS from February 2021 to January 2024. Patients with suspected nidus occlusion on the latest non-contrast-enhanced magnetic resonance angiography (NC-MRA) were included, and contrast-enhanced magnetic resonance angiography (CE-MRA), 2D-DSA, and 3D-RA were evaluated. RESULTS: Twelve patients with 13 AVM sites were defined as having complete nidus occlusion on upfront NC-MRA. On 2D-DSA, seven AVM sites showed the presence of slight remaining AVMs based on the detection of remnant drainage veins, however the nidus was not detected in three cases. Nevertheless, 3D-RA detected micro-remnant niduses in all seven AVM sites, and four patients underwent re-GKS. Nine patients with ten AVM sites also underwent CE-MRA, and six AVM sites were diagnosed with radiation-induced parenchymal injury. CONCLUSION: Importing the 3D-RA image into the treatment planning has the potential to be more helpful than NC-MRA or CE-MRA to detect micro-remnant AVMs and evaluate the true remnant volume, and may contribute to a more detailed treatment planning, thereby improving the results of GKS retreatment.

Intracanal removal and apical extrusion of filling material after retreatment using rotary or reciprocating instruments: A new approach using human cadavers.

AIM: This study compared intracanal removal of filling as well as the frequency and volume of extruded material after retreatment with either HyFlex or Reciproc instruments in mandibular teeth from cadavers. METHODOLOGY: The root canals of 14 pairs of contralateral single-rooted teeth in mandibles of cadavers were instrumented with Reciproc R40 and filled using lateral compaction. The mandibles were scanned in a micro-computed tomographic (micro-CT) device before and after retreatment procedures. The contralateral teeth were assigned to two groups (n = 14) according to the retreatment protocol using either HyFlex or Reciproc instrument systems. In the HyFlex group, the HyFlex Remover instrument was worked 3 mm short of the working length (WL), followed by HyFlex CM 40.04 and 50.04 at the WL. In the Reciproc group, the R50 instrument was worked up at the coronal two thirds, followed by two more cycles until the WL was reached. Pre- and post-operative micro-CT images were analysed for extrusion and intracanal removal of filling material. RESULTS: After retreatment, extrusion of filling material occurred in 11 (78%) and 14 (100%) teeth from HyFlex and Reciproc groups respectively (p > .05). A similar volume of extruded material was observed after retreatment with both systems (p > .05). A significant decrease in the intracanal filling volume was verified after retreatment with both tested systems (p < .05). However, residual filling material was found in all root canals, regardless of the system. The amount of filling material removed (HyFlex = 80.8%; Reciproc = 65.9%) and the operation time was similar between systems (p > .05). CONCLUSIONS: A high frequency of filling material extrusion was observed after retreatment with the two systems in a cadaver model, with no significant difference between them. Both protocols obtained similar efficacy in filling material removal procedures, although none completely cleaned the canals.

Why do dentists refrain from intervention in cases of persistent asymptomatic apical periodontitis in root canal filled teeth? An interview study among general dental practitioners.

AIM: To explore the context in which general dental practitioners (GDPs) decide to refrain from further treatment, that is, ortho- or retrograde retreatment or extraction of a root canal filled tooth with persistent asymptomatic apical periodontitis (PAAP). METHODOLOGY: Fifteen GDPs were strategically selected for in-depth interviews. The informants were encouraged to describe in their own words and in as much detail as possible, the three most recent patient cases of PAAP of a root canal filled tooth, in which they decided to refrain from further treatment. The interviews were recorded digitally and transcribed verbatim. The collected material was analysed according to Qualitative Content Analysis with an inductive approach. RESULTS: A pattern of varying degrees of uncertainty associated with the decision process was identified. The motives to refrain intervention had great diversity. The result from analysis of the qualitative data was formulated in an overall theme 'Between doubt and certainty in a complex clinical context' covering the latent content. The first main category covering the manifest content was 'The continuum of confidence' with three subcategories 'Experienced uncertainty', 'Reluctant approval' and 'At ease with refraining' illustrating the feelings and attitudes experienced by the informants. The second category was 'In support of acceptance' with three subcategories 'Patient's autonomy, risks and cost-benefits', 'Emotional aspects' and 'Relieving measures' representing the reasons for refraining from intervention. CONCLUSIONS: The decision to refrain from further treatment, that is, ortho- or retrograde retreatment or extraction of a root canal filled tooth with PAAP was made with some measure of confidence, combined with compensatory strategies to support the decision, taking into account not only values beneficial to the patient and awareness of limited external resources, but also factors related to the informants' personal preferences, convenience, concerns, ambition and emotions.

Interventions in root-filled teeth identified in general dental practice: A 6-year longitudinal observational study.

AIM: To investigate what happens to cross-sectionally identified root-filled teeth over a 6-year period, regardless of the time that elapsed since primary root canal treatment, in a cohort of adult patients regularly attending a Public Dental Service. A secondary aim was to investigate how the cumulative events affecting root-filled teeth over the same time were associated with variables obtained from a baseline examination. METHODOLOGY: Adult patients with ≥1 previously root-filled tooth and regularly attending the Public Dental Service in Örebro County were enrolled for study participation in 2015. General dental practitioners examined all identified root-filled teeth in this cohort at baseline using a standardized protocol and were also responsible for further decision-making and treatments. After six years, information on events of the root-filled teeth was collected from dental records. The highest rating (most invasive treatment) on a 5-point ordinal scale was used in the analyses. Regression analyses with stepwise selection were performed for associations between patient- and tooth-related factors and events. RESULTS: A total of 445 patients with 1007 root-filled teeth were followed the entire observation time. Twenty (2.0%) of the root-filled teeth had endodontic retreatment and 150 (14.9%) were extracted over six years. Among teeth with periapical radiolucency or pain, the majority did not undergo retreatment or extraction; however, the multivariate analysis demonstrated that retreatment or extraction was associated with baseline recordings of teeth with periapical radiolucency (p < .0001), tenderness to percussion (p < .0001), and poor coronal restoration (p < .0001). CONCLUSIONS: This study corroborates the notion that in general dentistry, root-filled teeth with radiological signs of apical disease often remain untreated over time. Furthermore, it also reveals that root-filled teeth presenting with mild pain do not necessarily receive any intervention. However, teeth with baseline signs of apical periodontitis, pain, or inadequate coronal restoration were more likely to have received intervention during the six-year period.

Effect of the filling technique on the filling removal from oval-shaped canals.

OBJECTIVES: This ex vivo study aimed to evaluate the influence of different filling techniques on the filling removal from oval root canals filled with bioceramic sealer. METHODS: Thirty-six mandibular incisors with single oval canals were filled with bioceramic sealer following the techniques (n = 12): single-cone, modified McSpadden, or continuous wave of condensation, and scanned by micro-computed tomography (micro-CT). The filling was removed using the Clearsonic ultrasound tip and Reciproc system up to the R40 instrument, and the working time was recorded. The teeth were scanned again by micro-CT. Percentage of remnant volume (mm³) of the filling material, dentin thickness, and root canal transportation were measured. The data was analyzed using parametric and non-parametric tests with a significance level of 5%. RESULTS: It took more time to remove the filling material using the continuous wave of condensation technique (p < 0.05), followed by the modified McSpadden and single-cone techniques. There was no difference (p > 0.05) when comparing the percentage of remaining filling material among the three groups, nor did it among the segments of each tooth. There was also no difference in the analysis of dentin thickness and transportation when comparing the groups (p > 0.05). CONCLUSIONS: The filling technique did not influence the amount of remaining filling material, dentin thickness, and transportation. The working time was longer with thermoplastic filling techniques. CLINICAL RELEVANCE: Endodontic retreatment in teeth filled with bioceramic sealers increases with their use. Several techniques are used to fill the root canals, thus, it is important to know whether the filling technique influences the non-surgical endodontic retreatment.

Root canal cleanliness and debris extrusion following retreatment of thermoplastic injection technique and bioceramic-based root canal sealer.

OBJECTIVES: To evaluate the amount of apically extruded debris and to determine the remaining filling material on the root canal walls by microcomputed tomography (micro-CT), following the root canal retreatment of root canals filled with different obturation techniques (single cone technique, thermoplasticised injection technique) and the different root canal sealers [bioceramic-based, epoxy resin-based root canal sealer]. MATERIALS AND METHODS: 60 single rooted human premolar teeth were prepared with the ProTaper Gold system (Dentsply Maillefer) up to the F4 file and the samples were divided into 4 groups according to obturation procedures: Single cone technique + AH Plus sealer(epoxy resin-based root canal sealer, Dentsply International Inc., York, PA, USA); Single cone technique + Sure-Seal Root(bioceramic-based root canal sealer, Sure Dent Corporation, Gyeonggi-do, South Korea); thermoplastic injection technique[Calamus Dual Obturation System(Dentsply-Tulsa Dental, Tulsa, OK, USA)] + AH Plus(Dentsply International Inc.); Sure-Seal Root(Sure Dent Corporation) + Calamus Dual Obturation System (Dentsply-Tulsa Dental). The teeth were inserted into preweighed Eppendorf tubes and retreatment was performed. The tubes were kept in an incubator at 37 °C for 14 days to obtain the dry debris weight. Following the removal of the root canal fillings, the samples were scanned with a micro-CT device to analyse the volume of filling residues. RESULTS: Retreatment of samples obturated with epoxy-resin or bioceramic based root sealers combined with Calamus system resulted in higher amount of apical extrusion compared to their combination with single cone technique (p = 0.026 for Single cone technique + AH Plus sealer vs Calamus + AH Plus sealer and p = 0.005 for Single cone technique + Sure-Seal root sealer vs Calamus + Sure-Seal root sealer). The most debris was observed in the Calamus + Sure-Seal root sealer group, the least debris was observed in the Single cone technique + AH Plus sealer group. The percentage of residues was the highest in the Single cone technique + Sure-Seal root sealer and the lowest in the Calamus + AH Plus sealer group, but there were no significant differences between groups (p = 0.463). CONCLUSIONS: No correlation was observed among the groups in terms of extruded debris and remnants inside the root canal. When combined with bioceramic based sealer, thermoplasticised injection technique did not affect the cleanliness of root canal walls; however, it increased its apical extrusion potential during retreatment. CLINICAL RELEVANCE: The obturation method does not play a role in the removability of bioceramic based root canal sealer, however the use of bioceramic-based root canal sealers with cold obturation techniques may be beneficial in preventing apical extrusion.

Removal of fiber posts using conventional versus guided endodontics: a comparative study of dentin loss and complications.

OBJECTIVES: To compare the efficacy of fiber post removal using conventional (CONV) versus guided endodontics (GE) in terms of dentin loss, residual resin material, procedural errors, and working time in vitro. MATERIAL AND METHODS: Ninety human central incisors were root-filled and scanned by micro-computed tomography (CT), then restored with fiber posts and composite. Twenty-four sets of teeth with up to four human maxillary central incisors were fabricated and divided into three groups: conventional post removal by a general dentist (CG) or endodontology specialist (CS) and guided endodontics (GE) by a general dentist, yielding 30 teeth per operator and group. After treatment, the prepared access cavities were volumetrically assessed by micro-CT. Statistical significance was evaluated by one-way analysis of variance followed by post hoc comparisons with Tukey's HSD test and Pearson's chi-squared test for independence. RESULTS: Both CONV and GE resulted in dentin loss and residual resin material. CS resulted in more dentin loss and less residual resin material than CG and GE (p < .05). All groups had some deviations from the original root canal but no perforations. The shortest working time was observed in the GE group. CONCLUSIONS: Compared to the conventional freehand technique, GE resulted in significantly less radicular dentin loss, a few deviations but no perforations. CLINICAL RELEVANCE: Guided endodontics can improve the speed and safety of fiber post removal without root perforation.

Evaluation of changes in root canal length and accuracy of the electronic apex locator during different stages of endodontic treatment and retreatment.

This study evaluated changes in the root canal length (RCL) and the accuracy of the electronic apex locator (EAL) during the different stages of endodontic treatment and retreatment. Fifty-six mesial root canals of mandibular molars were selected. The actual root canal length (AL) of the canals was obtained by inserting a size 15 hand file up to the apical foramen, under magnification. The electronic lengths were obtained at the "APEX" mark of Root ZX II, using an alginate model. Both measurements were performed at three different stages of the initial root canal treatment-unflared, flared, and concluded-and at two stages of retreatment, after achieving patency and repreparation. Data were statistically analyzed and the significance level established was 5%. All stages produced a significant reduction in the AL (p < 0.05). The greatest variation was observed between the unflared-flared stages (0.2 mm) and between concluded-patency stages (0.09 mm), with no difference between them (p > 0.05). The accuracy of Root ZX II was negatively affected after achieving patency, presenting statistically significant difference compared to the other stages (p < 0.05). A significant reduction in the RCL was observed along the different stages of endodontic treatment and retreatment. The EAL was accurate to measure the root canals in most stages, except after achieving patency for endodontic retreatment. Determining and monitoring the RCL is an essential step towards a favorable prognosis, since it reduced along the different stages evaluated. Root ZX II was not accurate for endodontic retreatment.

Fluorescence intensity of composite resin for direct veneer removal using a fluorescence-aided identification technique.

OBJECTIVES: This laboratory study evaluated the influence of the fluorescence intensity of composite resins on additional tooth wear and the presence of restorative material in different dental thirds during the retreatment of direct veneers. MATERIALS AND METHODS: The crown dimensions of 60 bovine incisors were reduced to 10 × 8 mm. The teeth were classified according to the fluorescence intensity of the composites: low (LOW) (TPH Spectra), medium (MED) (Opallis), and high (HIGH) (Essentia) groups. The teeth were divided according to the removal methods: conventional (CON) and fluorescence-aided identification technique (FIT). The specimens were scanned (T0), received veneer preparation, and scanned again (T1). After restorations, the composites were removed and the teeth were scanned (T2). Measurement assessments between T1 and T2 were performed to determine additional wear, presence of residual areas, and the average between additional wear and the presence of residual areas. Kruskal Wallis, Mann-Whitney, Friedman, 2-way ANOVA, and post-Tukey tests were performed (α < 0.05). RESULTS: The comparison of composite resins indicated a smaller area of additional wear and greater residue presence in the HIGH group than the LOW group for both techniques in the cervical third. Regarding removal methods, the FIT produced greater additional wear than the CON method for the LOW and MED groups in the middle and cervical thirds. The incisal third exhibited greater additional wear than the other thirds. CONCLUSIONS: Composite resins with high fluorescence intensity removed using FIT had less tooth wear. The incisal third was the most affected area for direct veneer removal procedures. CLINICAL SIGNIFICANCE: A FIT has been proposed for composite resin removal; however, the different fluorescence intensities of composite resins can influence tooth wear caused during this procedure.

Radiation therapy communication: Retreatment of multiple histologically confirmed oligodendroglioma drop metastasis with stereotactic radiotherapy in a dog.

A 10-year-old female spayed boxer was treated with stereotactic radiotherapy (SRT) for a suspected glioma in the left piriform lobe. The intra-axial lesion was T2 hyperintense, T2 FLAIR hyperintense, T1 hypointense, and did not uptake contrast. Imaging was performed with an MRI every 3 months, and at the 6-month recheck, new lesions in the left hippocampus and right piriform lobe were evident without clinically apparent neurological progression. A second course of SRT was prescribed for the new lesions. Euthanasia was elected 14 months after the first course of SRT, and necropsy confirmed oligodendroglioma with drop metastasis.