Different prognostic values of KRAS exon 2 submutations and BRAF V600E mutation in microsatellite stable (MSS) and unstable (MSI) stage III colon cancer: an ACCENT/IDEA pooled analysis of seven trials.

BACKGROUND: The prognostic value of KRAS and BRAFV600E mutations in stage III colon cancer (CC) remains controversial and has never been clearly analyzed in patients with microsatellite instability-high (MSI-H) tumors due to sample size limitations. Data are also lacking for KRAS submutations and prognosis. PATIENTS AND METHODS: We examined clinicopathological variables and prognosis in patients with surgically resected stage III CC who participated in seven clinical trials from the ACCENT/IDEA databases. Associations between KRAS exon 2 and BRAFV600E mutations and time to recurrence (TTR), overall survival (OS), and survival after recurrence (SAR) were assessed using a Cox model. We also analyzed the prognostic value of KRAS exon 2 submutations. RESULTS: Among 8460 patients, 11.4% had MSI-H status. In the MSI-H group, BRAFV600E, KRAS exon 2 mutants, and double-wild-type statuses were detected in 40.6%, 18.1%, and 41.3%, respectively, whereas and in the microsatellite stable (MSS) group, these were detected in 7.7%, 38.6%, and 53.8%, respectively. In the MSS group, 5-year TTR rates of 61.8%, 66.3%, and 72.9% were observed among patients with BRAFV600E, KRAS exon 2 mutants, and those who were DWT, respectively [adjusted hazard ratio (HR) = 1.58 and 1.31, both P < 0.001]. In the MSI-H group, 5-year TTR rates did not differ significantly among the mutated subgroups. Similar results were found for OS. However, survival after relapse was significantly shorter in the KRAS exon 2- and BRAFV600E-mutated patients in both MSS (adjusted HR = 2.06 and 1.15; both P < 0.05) and MSI-H (adjusted HR = 1.99 and 1.81; both P < 0.05) groups. In the MSS group, KRAS exon 2 mutations were associated with TTR, but only p.G12C, p.G12D, and p.G13D were associated with poor outcomes after disease recurrence. CONCLUSIONS: Testing for both KRAS and BRAFV600E mutations in stage III patients should be considered as they can better define individual patient prognosis, and may also enable patient selection for (neo)adjuvant trials dedicated to specific molecular subtypes with poor prognosis.

Comparison of sodium hypochlorite extrusion by five irrigation systems using an artificial root socket model and a quantitative chemical method.

OBJECTIVES: This is to compare the volumes of irrigant apically extruded by five irrigation systems in an artificial socket model simulating clinical conditions. MATERIALS AND METHODS: Twenty extracted human single-rooted teeth were enlarged to size 40/04 and then embedded in silicone impression material. The root canal space was irrigated with nominal 3% sodium hypochlorite (NaOCl) using standard needle irrigation (SNI) with a 30-gauge notched needle, EndoActivator (EA), XP Endo Finisher (XP Endo), EndoVac (EV), and photon-induced photoacoustic streaming (PIPS). Extruded NaOCl was collected, reacted with taurine to form taurine-monochloramine, and absorbance of taurine-monochloramine was measured at 252 nm using a spectrophotometer. The five irrigation systems were compared with repeated measures ANOVA and pairwise comparisons. RESULTS: The EV group had very low extrusion (mean ± SD = 0.12 ± 0.2 µL) and differed significantly from the other four groups (P ≤ 0.001). Larger volumes of irrigant were extruded in the other irrigation groups. There were no significant differences in the extruded volumes among the SNI (7.4 ± 3.4 µL), EA (7.0 ± 6.1 µL), and XP Endo (7.8 ± 4.1 µL) groups (P = 1). The PIPS group had the highest mean extruded volume (12.9 ± 6.8 µL) and differed significantly from SNI (P = 0.030), EV (P < 0.0005), and EA (P = 0.02), but not XP Endo (P = 0.154). CONCLUSION: Under the in vitro conditions of this study, irrigant extrusion appears unavoidable unless negative pressure irrigation such as EV is used. PIPS extrudes more irrigant than other systems, while SNI, EA, and XP Endo extrude similar volumes of irrigant. CLINICAL RELEVANCE: The findings help clinicians select the optimal irrigation system to avoid irrigant extrusion.

Cementogenic genes in human periodontal ligament stem cells are downregulated in response to osteogenic stimulation while upregulated by vitamin C treatment.

Regeneration of periodontal tissues, particularly cementum, is key to regaining periodontal attachment and health. Human periodontal ligament stem cells (hPDLSCs) have been shown to be a good cell source to regenerate periodontal tissues. However, their subpopulations and the differentiation induction in relation to cementogenic lineages is unclear. Thus, we aim to examine the expression of cementum-associated genes in PDLSC subpopulations and determine the effect of broadly used osteogenic stimulus or vitamin C (VC) on the expression of cementogenic and osteogenic genes in PDLSCs. Our real-time quantitative polymerase chain reaction (qPCR) analysis showed that cementogenic marker cementum attachment protein (CAP) expressed only slightly higher in STRO-1+/CD146+, STRO-1-/CD146+ and STRO-1-/CD146- subpopulations than in the original cell pool, while cementum protein 1 (CEMP1) expression in these subpopulations was not different from the original pool. Notably, under the stimulation with osteogenic differentiation medium, CAP and CEMP1 were downregulated while osteogenic markers bone sialoprotein (BSP) and osteocalcin (OCN) were upregulated. Both CAP and CEMP1 were upregulated by VC treatment. Transplantation of VC-treated PDLSCs into immunocompromised mice resulted in forming significantly more ectopic cementum- and bone-like mineral tissues in vivo. Immunohistochemical analysis of the ectopic growth showed that CAP and CEMP1 were mainly expressed in the mineral tissue and in some cells of the fibrous tissues. We conclude that osteogenic stimulation is not inductive but appears to be inhibitory of cementogenic pathways, whereas VC induces cementogenic lineage commitment by PDLSCs and may be a useful stimulus for cementogenesis in periodontal regeneration.

Comprehensive genomic profiling of anal squamous cell carcinoma reveals distinct genomically defined classes.

BACKGROUND: Squamous cell cancers of the anal canal (ASCC) are increasing in frequency and lack effective therapies for advanced disease. Although an association with human papillomavirus (HPV) has been established, little is known about the molecular characterization of ASCC. A comprehensive genomic analysis of ASCC was undertaken to identify novel genomic alterations (GAs) that will inform therapeutic choices for patients with advanced disease. PATIENTS AND METHODS: Hybrid-capture-based next-generation sequencing of exons from 236 cancer-related genes and intronic regions from 19 genes commonly rearranged in cancer was performed on 70 patients with ASCC. HPV status was assessed by aligning tumor sequencing reads to HPV viral genomes. GAs were identified using an established algorithm and correlated with HPV status. RESULTS: Sixty-one samples (87%) were HPV-positive. A mean of 3.5 GAs per sample was identified. Recurrent alterations in phosphoinositol-3-kinase pathway (PI3K/AKT/mTOR) genes including amplifications and homozygous deletions were present in 63% of cases. Clinically relevant GAs in genes involved in DNA repair, chromatin remodeling, or receptor tyrosine kinase signaling were observed in 30% of cases. Loss-of-function mutations in TP53 and CDKN2A were significantly enhanced in HPV-negative cases (P < 0.0001). CONCLUSIONS: This is the first comprehensive genomic analysis of ASCC, and the results suggest new therapeutic approaches. Differing genomic profiles between HPV-associated and HPV-negative ASCC warrants further investigation and may require novel therapeutic and preventive strategies.

What is Missing for Stem Cell-Based Therapies in Dentistry.

There have been significant advancements in regenerative dentistry demonstrated in large animal studies, particularly in the areas of endodontics and periodontics. By using dental stem cells, pulp tissues can be regenerated in empty root canal space, and periodontal pockets can be regenerated to its normal state. To further test its clinical applications and perhaps to provide such patient care service if proven safe and successful, a facility called good manufacturing practice where stem cells are processed is needed. However, such facilities are rare.

ALLIANCE A022104/NRG-GI010: The Janus Rectal Cancer Trial: a randomized phase II/III trial testing the efficacy of triplet versus doublet chemotherapy regarding clinical complete response and disease-free survival in patients with locally advanced rectal cancer.

Background: Recent data have demonstrated that in locally advanced rectal cancer (LARC), a total neoadjuvant therapy (TNT) approach improves compliance with chemotherapy and increases rates of tumor response compared to neoadjuvant chemoradiation (CRT) alone. They further indicate that the optimal sequencing of TNT involves consolidation (rather than induction) chemotherapy to optimize complete response rates. Data, largely from retrospective studies, have also shown that patients with clinical complete response (cCR) after neoadjuvant therapy may be managed safely with the watch and wait approach (WW) instead of preemptive total mesorectal resection (TME). However, the optimal consolidation chemotherapy regimen to achieve cCR has not been established, and a randomized clinical trial has not robustly evaluated cCR as a primary endpoint. Collaborating with a multidisciplinary oncology team and patient groups, we designed this NCI-sponsored study of chemotherapy intensification to address these issues and to drive up cCR rates, to provide opportunity for organ preservation, improve quality of life for patients and improve survival outcomes. Methods: In this NCI-sponsored multi-group randomized, seamless phase II/III trial (1:1), up to 760 patients with LARC, T4N0, any T with node positive disease (any T, N+) or T3N0 requiring abdominoperineal resection or coloanal anastomosis and distal margin within 12 cm of anal verge will be enrolled. Stratification factors include tumor stage (T4 vs T1-3), nodal stage (N+ vs N0) and distance from anal verge (0-4; 4-8; 8-12 cm). Patients will be randomized to receive neoadjuvant long course chemoradiation (LCRT) followed by consolidation doublet (mFOLFOX6 or CAPOX) or triplet chemotherapy (mFOLFIRINOX) for 3-4 months. LCRT in both arms involves 4500 cGy in 25 fractions over 5 weeks + 900 cGy boost in 5 fractions with a fluoropyrimidine (capecitabine preferred). Patients will undergo assessment 8-12 (+/- 4) weeks post-TNT completion. The primary endpoint for the phase II portion will compare cCR between treatment arms. A total number of 296 evaluable patients (148 per arm) will provide statistical power of 90.5% to detect an 17% increase in cCR rate, at a one-sided alpha=0.048. The primary endpoint for the phase III portion will compare disease-free survival (DFS) between treatment arms. A total of 285 DFS events will provide 85% power to detect an effect size of hazard ratio 0.70 at a one-sided alpha of 0.025, requiring enrollment of 760 patients (380 per arm). Secondary objectives include time-to event outcomes (overall survival, organ preservation time and time to distant metastasis) and adverse effects. Biospecimens including archival tumor tissue, plasma and buffy coat in EDTA tubes, and serial rectal MRIs will be collected for exploratory correlative research. This study, activated in late 2022, is open across the NCTN and has a current accrual of 312. Support: U10CA180821, U10CA180882, U24 CA196171; https://acknowledgments.alliancefound.org . Discussion: Building off of data from modern day rectal cancer trials and patient input from national advocacy groups, we have designed the current trial studying chemotherapy intensification via a consolidation chemotherapy approach with the intent to enhance cCR and DFS rates, increase organ preservation rates, and improve quality of life for patients with rectal cancer. Trial Registration: Clinicaltrials.gov ID: NCT05610163 ; Support includes U10CA180868 (NRG) and U10CA180888 (SWOG).

Bone marrow stromal cells produce long-term pain relief in rat models of persistent pain.

Chronic pain conditions are difficult to treat and are major health problems. Bone marrow stromal cells (BMSCs) have generated considerable interest as a candidate for cell-based therapy. BMSCs are readily accessible and are easy to isolate and expand ex vivo. Clinical studies show that direct injection of BMSCs does not produce unwanted side effects and is well tolerated and safe. Here, we show that a single systemic (intravenous) or local injection (into the lesion site) of rat primary BMSCs reversed pain hypersensitivity in rats after injury and that the effect lasted until the conclusion of the study at 22 weeks. The pain hypersensitivity was rekindled by naloxone hydrochloride, an opioid receptor antagonist that acts peripherally and centrally, when tested at 1-5 weeks after BMSC infusion. In contrast, naloxone methiodide, a peripherally acting opioid receptor antagonist, only rekindled hyperalgesia in the first 3 weeks of BMSC treatment. Focal downregulation of brainstem mu opioid receptors by RNA interference (RNAi) reversed the effect of BMSCs, when RNAi was introduced at 5- but not 1-week after BMSC transplantation. Thus, BMSCs produced long-term relief of pain and this effect involved activation of peripheral and central opioid receptors in distinct time domains. The findings prompt studies to elucidate the cellular mechanisms of the BMSC-induced pain relieving effect and translate these observations into clinical settings.

The Four Pillars for Successful Regenerative Therapy in Endodontics: Stem Cells, Biomaterials, Growth Factors, and Their Synergistic Interactions.

Endodontics has made significant progress in regenerative approaches in recent years, thanks to advances in biologically based procedures or regenerative endodontic therapy (RET). In recent years, our profession has witnessed a clear conceptual shift in this therapy. RET was initially based on a blood clot induced by apical bleeding without harvesting the patient's cells or cell-free RET. Later, the RET encompassed the three principles of tissue engineering, stromal/stem cells, scaffolds, and growth factors, aiming for the regeneration of a functional dentin pulp complex. The regenerated dental pulp will recover the protective mechanisms including innate immunity, tertiary dentin formation, and pain sensitivity. This comprehensive review covers the basic knowledge and practical information for translational applications of stem cell-based RET and tissue engineering procedures for the regeneration of dental pulp. It will also provide overall information on the emerging technologies in biological and synthetic matrices, biomaterials, and signaling molecules, recent advances in stem cell therapy, and updated experimental results. This review brings useful and timely clinical evidence for practitioners to understand the challenges faced for a successful cell-based RET and the importance of preserving or reestablishing tooth vitality. The clinical translation of these current bioengineering approaches will undoubtedly be beneficial to the future practice of endodontics.

Effects of intentionally treated water on the growth of mesenchymal stem cells: An exploratory study.

OBJECTIVE: This study explored if human primary mesenchymal stem cells (MSCs), derived from two donors and cultivated in a medium made with intentionally treated water, would exhibit more growth and pluripotency than MSCs from the same source but grown in untreated (control) water. DESIGN: To create the treated water, three Buddhist monks directed their attention toward commercially bottled water while holding the intention that the water would enhance the growth of MSCs. Under double-blind conditions, cell culture growth mediums were prepared with the treated and untreated water, which was in turn used to grow the primary MSCs. Primary cells obtained from two donors were designated as Cells #1 and Cells #2. The prediction was that treated water would result in increased cell proliferation, that more cells would enter the cell cycle growth phase, and that there would be increased expression of genes (NANOG, OCT4 and SOX2) associated with improved cell growth and decreased expression of genes (p16, p21, and p53) associated with a decline in cell growth. The improved growth hypothesis was directional, thus one-tailed p-values were used to evaluate the results. RESULTS: Proliferation averaged across Cells #1 and #2 showed overall increased growth in treated as compared to control water (p = 0.0008). Cells #1 and #2 considered separately had differences in the same direction but only Cells #2 showed a significant difference on day 6 (p = 0.01). For cell cycle, there was a significantly greater percentage of Cells #2 in the S interphase with treated vs. control water (p = 0.04). For the gene expression analysis, when considering the average across the two donor cells, only the NANOG gene expression was in the predicted direction (p = 0.01); by contrast, the p16 gene expression was significantly opposite to the predicted direction (p = 0.005, one-tailed, post-hoc). For Cells #1 considered separately, no differences were significant except for p16, which resulted in an effect opposite to the predicted outcome (p = 0.05). For Cells #2, three genes were significantly in the predicted directions: NANOG (p = 0.0008), OCT4 (p = 0.005), and P53 (p = 0.05); p16 was significantly opposite to the prediction (p = 0.001). CONCLUSION: Intentionally treated water appeared to have some biological effects on the growth, pluripotency and senescence of human MSCs. This was especially the case in one of the two donor cells tested, but the effects were not consistently in the predicted direction. As an exploratory study, caution is warranted in interpreting these outcomes, and adjustment for multiple testing would likely reduce some of the weaker effects to nonsignificant. But given the double-blind protocol, as well as several more significant outcomes in the predicted directions, further research is warranted.

A new direction in managing avulsed teeth: stem cell-based de novo PDL regeneration.

Management of avulsed teeth after replantation often leads to an unfavorable outcome. Damage to the thin and vulnerable periodontal ligament is the key reason for failure. Cell- or stem cell-based regenerative medicine has emerged in the past two decades as a promising clinical treatment modality to improve treatment outcomes. This concept has also been tested for the management of avulsed teeth in animal models. This review focuses on the discussion of limitation of current management protocols for avulsed teeth, cell-based therapy for periodontal ligament (PDL) regeneration in small and large animals, the challenges of de novo regeneration of PDL on denuded root in the edentulous region using a mini-swine model, and establishing a prospective new clinical protocol to manage avulsed teeth based on the current progress of cell-based PDL regeneration studies.

Cell-derived Extracellular Matrix Proteins in Colloidal Microgel as a Self-Assembly Hydrogel for Regenerative Endodontics.

INTRODUCTION: This study investigated a colloidal microgel for angiogenic and odontogenic differentiation of cells in the presence of cell-derived extracellular matrix (ECM) proteins using a 3-dimensional culture model. METHODS: Viscoelastic properties of human dental pulp were determined to understand the native ECM environment. ECM proteins were extracted from dental pulp stem cell (DPSC) cultures, and MaxGel (Millipore Sigma, Burlington, MA) was used as a commercially available ECM protein. DPSCs were incubated in colloidal microgels in the presence of ECM proteins or gelatin methacryloyl (GelMA) as a bulk hydrogel (n = 9/group). The viability and odontogenic differentiation of DPSCs within hydrogels was determined using viability assays, mineralization staining, calcium and alkaline phosphatase assays, and quantitative polymerase chain reaction for odontogenic gene expression. Angiogenic properties of endothelial cells were determined using tubule formation assays and quantitative polymerase chain reaction to detect angiogenic gene expression. RESULTS: Dental pulp had a higher elastic modulus than the viscous modulus, showing a solidlike response similar to hydrogels. DPSC-derived ECM showed higher collagen and GAG than MaxGel (P < .05). The viability of DPSCs was similar in colloidal microgels, whereas higher cell viability, calcium deposition, and alkaline phosphatase activity were observed in GelMA (P < .05). Colloidal microgels allowed tubule-like structures by endothelial cells, whereas no tubular formation was observed in GelMA. DPSC-derived ECM in colloidal microgel up-regulated odontogenic gene expression, whereas MaxGel up-regulated angiogenic gene expression (P < .05). CONCLUSIONS: Colloidal microgels allowed cellular organization that can improve penetration and nutritional supply in a full-length root canal system. The bioactivity of cell-derived ECM proteins can be modified depending on the external stimulus.

The coming era of regenerative endodontics: what an endodontist needs to know.

Recently, two new clinical concepts have emerged for the management of endodontically compromised immature permanent teeth. One involves a revitalization approach to achieve tissue generation and regeneration in the root canal system. In this method, new living tissue is expected to form in the cleaned canal space allowing continued root development in terms of both length and thickness. The other is the active pursuit of pulp/dentine regeneration via tissue engineering technology to implant or re-grow pulps. Although the technology is still at its infancy, it has potential to benefit immature pulpless teeth by allowing continued growth and maturation. Evidence has shown that using dental stem cells, pulp and dentin can be regenerated in the root canal space. It is foreseeable that a decade or two from now, regenerative endodontics is likely to be an alternative treatment modality for clinical endodontics. It is therefore important for us to understand stem cells and tissue regeneration and be prepared for this clinical practice.

Potential of tailored amorphous multiporous calcium silicate glass for pulp capping regenerative endodontics-A preliminary assessment.

INTRODUCTION/OBJECTIVE: The tailored amorphous multi-porous (TAMP) material fabrication technology has led to a new class of bioactive materials possessing versatile characteristics. It has not been tested for dental applications. Thus, we aimed to assess its biocompatibility and ability to regenerate dental mineral tissue. METHODS: 30CaO-70SiO2 model TAMP discs were fabricated by a sol-gel method followed by in vitro biocompatibility testing with isolated human or mini-swine dental pulp stem cells (DPSCs). TAMP scaffolds were tested in vivo as a pulp exposure (pin-point, 1 mm, 2 mm, and entire pulp chamber roof) capping material in the molar teeth of mini-swine. RESULTS: The in vitro assays showed that DPSCs attached well onto the TAMP discs with comparable viability to those attached to culture plates. Pulp capping tests on mini-swine showed that after 4.5 months TAMP material was still present at the capping site, and mineral tissue (dentin bridge) had formed in all sizes of pulp exposure underneath the TAMP material. CONCLUSIONS: TAMP calcium silicate is biocompatible with both human and swine DPSCs in vitro and with pulp in vivo, it may help regenerate the dentin bridge after pulp exposure.

Dens evaginatus: Current treatment options.

BACKGROUND: Teeth with dens evaginatus (DE) are more commonly observed in Western countries than previously. This is due to the increase in populations of patients of Asian origin, in whom DE is more common than in people of European origin. The interest in DE has also increased with the introduction of a procedure called regenerative endodontics. CASE DESCRIPTION: A narrative review of treatment options for teeth with DE is presented, based on pulpal conditions and maturity of the teeth. PRACTICAL IMPLICATIONS: Early recognition of teeth with DE allows for treatment choices that generally lead to good outcomes and can aid in preserving developing teeth in young patients.

Pulp/Dentin Regeneration: It Should Be Complicated.

Stem cell-mediated regenerative endodontics has reached the human clinical trial phase; however, many issues still exist that prevent such technology to be a widely used clinical practice. These issues are not straightforward and are complicated. They should be because pulp regeneration is dealing with a small dead-end space. In addition, when regeneration is needed, the space is often heavily infected. The true standard of pulp regeneration should be everything except generation of some fibrous connective tissue and amorphous mineral deposit. As of now, we are still far short of reaching the standard of complete vascularized and innervated pulp regeneration with newly formed tubular dentin in all types of teeth. Thus, we need to go back to the bench and use established animal models or create new animal models to tackle those issues. This article will address several key issues including the possibility of pulp regeneration in small canals of molar teeth by enhancing the neovascularization, and whether the organized tubular dentin can be generated on the canal walls. Data from our semi-orthotopic tooth fragment mouse model have shown that complete pulp regeneration using dental pulp stem cells (DPSCs) in small canal has been inconsistent because of limited blood supply. This inconsistency is similar in our orthotopic miniature swine model, although in some cases vascularized pulp-like tissue can be formed throughout the canal space after DPSC transplantation. Furthermore, no tubular dentin was observed in the orthotopic pulp regeneration, despite the fact that DPSCs have the capacity to generate some tubular dentin-like structure in the hydroxyapatite/tricalcium phosphate-mediated ectopic pulp/dentin formation model in mice. Potential strategies to be tested to address these regeneration issues are discussed herein.

Nanobubble-Enhanced Antimicrobial Agents: A Promising Approach for Regenerative Endodontics.

INTRODUCTION: In this study, we investigated the properties of nanobubble (NB) water and its effect on smear layer removal and strengthening the efficiency of disinfecting agents used in regenerative endodontic treatment. METHODS: NB water was generated in a NB Generator. The NB size, concentration, and pH were measured. Porcine teeth were enlarged to size 60 by using hand-files and irrigated with either NB water or 17% EDTA or received no further irrigation. The ability of irrigants to remove the smear layer was evaluated by using a scanning electron microscope (9 roots/group). Other samples (6 roots/group) were subjected to Vickers hardness test to determine the dentin microhardness. Autofluorescent tetracycline mixed with distilled water or NB water was placed inside the root canal space of porcine teeth, and the depth of medicament penetration into the dentinal tubules was visualized by using fluorescent stereomicroscope (5 roots/group). For the disinfection experiment, human roots were prepared, autoclaved, and inoculated with Enterococcus faecalis for 3 weeks. Canals were then disinfected by (1) standard needle irrigation (SNI) with 5.25% NaOCl, (2) 5.25% NaOCl with ultrasonication (US), (3) 5.25% NaOCl + XP finisher (XP), (4) SNI with 1.5% NaOCl, or (5) SNI with 1.5% NaOCl in NB water (5 roots/group). Teeth were split open and stained with LIVE/DEAD BackLight and visualized by using confocal laser scanning microscope (CLSM) at the coronal, middle, and apical thirds of the canal. The ratio of dead/total bacteria in the dentinal tubules at various depth levels (50, 100, and 150 µm) was calculated. RESULTS: NB water was more effective in removing smear layer than 17% EDTA and could allow infiltration of tetracycline into the dentinal tubule more than 1 mm. NB water did not alter the dentin microhardness compared with 17% EDTA (P < .05). At 50-µm depth, CLSM analysis showed no statistically significant difference between 1.5% NaOCl in NB water and 5.25% NaOCl with or without irrigation activation at the coronal, middle, and apical root segments (P > .05), ie, these groups had stronger bacterial killing than 1.5% NaOCl (P < .05). At deeper levels (100 and 150 µm), higher concentrations of NaOCl were more effective than 1.5% NaOCl with or without NB water. No statistically significant difference was noted between 5.25% NaOCl with and without irrigation activation at most depth levels (P > .05). CONCLUSIONS: NB water can allow smear layer removal and enhance tubular penetration of medicaments without changing dentin microhardness. In large canal models, NB water appears to improve the tubular disinfection capacity of lower concentration of NaOCl up to 50 µm. On the other hand, the use of irrigation activation (US or XP) did not provide any added disinfection into the dentinal tubules compared with SNI. These results suggest that NB water may be a promising adjunct to endodontic irrigants and medicaments.

Dental Mesenchymal Stem Cells: Dental Pulp Stem Cells, Periodontal Ligament Stem Cells, Apical Papilla Stem Cells, and Primary Teeth Stem Cells-Isolation, Characterization, and Expansion for Tissue Engineering.

Dental stem cells (DSCs) have been shown to possess great potential for multiple biomedical applications, especially for dental tissue regeneration. They are a special type of subpopulation of mesenchymal stem/stromal cells (MSCs) and present subtle differences from other types of MSCs. Therefore, it requires a specialized expertise to isolate, culture, and characterize these cells in vitro and in vivo. The purpose of this chapter is to share our experience in studying these cells. We will describe in detail laboratory protocols outlining how the cells are isolated, cultured, expanded, and characterized using various in vitro cellular and biochemical analyses, as well as an in vivo study model using immunocompromised mice to observe tissue regeneration after transplantation of these DSCs.

Outcomes after intensity-modulated compared with 3-dimensional conformal radiotherapy with chemotherapy for squamous cell carcinoma of the anal canal.

Purpose: We report our institution's treatment techniques, disease outcomes, and complication rates after radiotherapy for the management of anal canal carcinoma with intensity-modulated radiotherapy (imrt) and concurrent chemotherapy relative to prior cases managed with 3-dimensional conformal radiotherapy (3D-crt). Methods: In a retrospective review of the medical records of 21 patients diagnosed with biopsy-proven stage i (23%), stage ii (27%), or stage iii (50%) squamous-cell carcinoma of the anal canal treated with curative chemotherapy and imrt between July 2009 and December 2014, patient outcomes were determined. Results for patients treated with 3D-crt by the same group were previously reported. The median initial radiation dose to the pelvic and inguinal nodes at risk was 45 Gy (range: 36-50.4 Gy), and the median total dose, including local anal canal primary tumour boost, was 59.4 Gy (range: 41.4-61.2 Gy). Patients received those doses over a median of 32 fractions (range: 23-34 fractions). Chemotherapy consisted of 2 cycles of concurrent fluorouracil-cisplatin (45%) or fluorouracil-mitomycin C (55%). Results: Median follow-up was 3.1 years (range: 0.38-6.4 years). The mean includes a patient who died of septic shock at 38 days. The 3-year rates of overall survival, metastasis-free survival, locoregional control, and colostomy-free survival were 95%, 100%, 100%, and 100% respectively. No patients underwent abdominoperitoneal resection after chemoradiotherapy or required diverting colostomy during or after treatment. Those outcomes compare favourably with the previously published series that used 3D-crt with or without brachytherapy in treating anal canal cancers. Of the 21 patients in the present series, 10 (48%) experienced acute grade 3, 4, or 5 toxicities related to treatment. Conclusions: The recommended use of imrt with concurrent chemotherapy as an improvement over 3D-crt for management of anal canal carcinoma achieves a high probability of local control and colostomy-free survival without excessive risk for acute or late treatment-related toxicities.

Animal Models for Stem Cell-Based Pulp Regeneration: Foundation for Human Clinical Applications.

IMPACT STATEMENT: Animal models are essential for tissue regeneration studies. This review summarizes and discusses the small and large animal models, including mouse, ferret, dog, and miniswine that have been utilized to experiment and to demonstrate stem cell-mediated dental pulp tissue regeneration. We describe the models based on the location where the tissue regeneration is tested-either ectopic, semiorthotopic, or orthotopic. Developing and utilizing optimal animal models for both mechanistic and translational studies of pulp regeneration are of critical importance to advance this field.