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Background Outcome studies of nonsurgical root canal treatment (NSRCT) in permanent teeth of children are scarce. This study investigated survival and assessed the variables associated with failure of endodontically treated teeth (ETT) in 6- to 18-year-olds. Methods Records of subjects who received NSRCT at age 6–18 years at Boston University between 2007 and 2015 were assessed for the occurrence of untoward events. Kaplan–Meier survival curves were used to investigate the survival of ETT in the total sample. Adjusted hazard ratios (aHRs) and 95% confidence intervals (CIs) were estimated. Results The analysis included 341 patients (424 ETT). Kaplan–Meier survival curves differed according to age at treatment (log-rank P = 0.026), with survival being the lowest among the youngest age group. The estimated 5-year survival probability was 80% for 15- to 18-year-olds, 64.8% for 12- to 14-year-olds and 46.4% for 6- to 11-year-olds. Compared to age at treatment of 15–18 years, age at treatment of 6–11 years (aHR: 2.19, 95% CI 1.02–4.67) and 12–14 years (aHR: 2.02, 95% CI 1.15–3.55) was associated with an increased risk of ETT failure. In the total study sample, the estimated cumulative survival probability was 93.3% at 12 months, 88.0% at 24 months, 76.2% at 36 months, 71.0% at 48 months, and 69.1% at 60 months. Conclusions In children, ETT are more likely to survive when NSRCTs are performed at an older age.

Introduction Cracked teeth are a common clinical finding; however, their presence renders diagnosis and prognosis unreliable. The purpose of this research was to assess the correlations of multiple factors on the prognosis of cracked teeth that had undergone endodontic treatment. Methods A total of 3680 patients who received endodontic treatment by an advanced postdoctoral education program in endodontics with follow-up records of at least 1 year were assessed. From this sample, 62 patients met the inclusion criteria and were included in the final analysis. The factors being evaluated included demographics, clinical symptoms and signs, radiographic findings, and restoration type. Statistical analysis was then completed using the chi-square and Fisher exact tests. Results The mean follow-up period was 23.3 months, with an overall tooth success rate of 75.8%. The success rates differed significantly when the patient had an existing preoperative periapical lesion, lacked a proper permanent restoration on the treated tooth, or had a post placed after root canal treatment. Data analysis showed that restoring the tooth after endodontic treatment was the single most important factor for prognosis. In fact, the endodontically treated teeth with definitive full-coverage restorations had a 2-year success rate of 93.6%. Conclusion Full-coverage restorations should be considered an important part of the treatment plan for cracked teeth treated endodontically.

Introduction Although intraoral radiographs are foundational for diagnosis and planning treatment in dentistry, the resulting 2-dimensional image varies in interpretation requiring judgment. Cone-beam computed tomographic imaging provides a more detailed 3-dimensional image that may affect treatment recommendations. This study aimed to determine the basis for CBCT recommendations and the effect on diagnosis and treatment planning. Methods The study involved a sample of 45 cases that presented for endodontic treatment, 30 with a CBCT scan on record and 15 without. For phase 1, all 45 cases were reviewed by 3 examiners without access to the CBCT scans. For phase 2, 4 months later, the 3 examiners reanalyzed the 30 cases, this time with the associated CBCT scan. Intra- and interexaminer agreements were recorded and analyzed. Also, the recommendations for CBCT were compared with the American Association of Endodontists/American Academy of Oral and Maxillofacial Radiology joint statement. Results Interexaminer agreement in phases 1 and 2 was 65% and 72%, respectively. For endodontic diagnoses, there was a 19% change in the pulpal diagnosis category when CBCT imaging was added, whereas there was a 30% change in the apical category. The selections changed in 55% of the cases when determining etiology and in 49% of the cases when making recommendations. CBCT imaging was recommended 78.8% of the time when the case had a CBCT on record versus 33% of the time in cases without. Conclusions CBCT imaging has a significant effect in determining the etiology of endodontic pathoses and in recommending treatment. Furthermore, CBCT imaging is not overprescribed in the endodontic department, and the faculty members adhere to the American Association of Endodontists/American Academy of Oral and Maxillofacial Radiology recommendations.

Summary Subjects or Study Selection: The electronic database search was completed using Pubmed, Science Direct, Lilacs, and Cochrane from May 2018 to September 2019. Five peer reviewed journals (International Endodontic Journal, Journal of Endodontics, Australian Endodontic Journal, Evidence Based Dentistry and Journal of Evidence Based Dental Practice) were searched as well. Additionally, there was a manual hand search of the bibliographic references within the previously identified studies. Unpublished data was requested from the author by email. All study titles and abstracts were reviewed for initial eligibility, and full text articles were reviewed for final inclusion and exclusion. Inclusion criteria were set to review in-vivo studies published between January 1990 to September 2019 that utilized CBCT scans with voxel sizes ≤200um and reported location of data collection. Critical appraisal as per Joanna Briggs Institute (JBI) was completed by 2 evaluators to include only studies with a JBI critical appraisal of ≥50%. Review studies, case reports, and endodontically treated teeth were excluded.

Article Title and Bibliographic Information A systematic review and meta-analysis of randomized clinical trials comparing rotary canal instrumentation techniques with manual instrumentation techniques in primary teeth. Manchanda S, Sardana D, Yiu CKY. Int Endod J. 2020;53(3):333-353. Source of Funding Information not available. Type of Study/Design Systematic review with meta-analysis of data.

Article Title And Bibliographic Information Correlation between symptoms and external characteristics of cracked teeth. Hilton TJ, Funkhouser E, Ferracane JL, Gilbert GH, Baltuck C, Benjamin P, Louis D, Mungia R, Meyerowitz. JADA 2017; 148(4):246-56.e1. Source of Funding National Institutes of Health grant U19-DE-22516 Type of Study/Design Cross-sectional study

Introduction: This study assessed the opinions on and practice of regenerative endodontic procedures (REPs) among clinicians from different dental specialties. Materials and Methods: After the Institutional Review Board approval, 205 clinicians participated in a web-based survey and were asked about their educational level, professional status, opinion toward REPs, and preferred technique when performing REPs. Results: Although approximately 65% of participants were unsure or did not believe that there is enough evidence to support REPs, 78.2% believed that REPs are a better treatment option than apexification and 70.5% that they could be a future alternative to osseointegrated implants. The results also revealed variability in the preferred techniques to perform REPs, with 40.4% preferring the use of a mixture of antibiotics to disinfect the root canal space, whereas 20.2% preferred calcium hydroxide. Almost 66% were using ≥1 mg/mL of each antibiotic in the mixture, whereas 44.6% were using 0.1 mg/mL. Approximately 40% of participants used techniques that differ from the American Association of Endodontists' clinical considerations for REPs. Interestingly, attending a continuing dental education course (CDE) significantly reduced the participants' uncertainty toward REPs and increased their willingness to perform it themselves (P Conclusions: This survey revealed a positive attitude toward and general acceptance of REPs by dentists. It also showed considerable variability in techniques used to perform REPs. Conducting more CDE may increase the awareness of REPs among different dental specialties and reducing variability in techniques.

Biodegradable scaffolds are useful tools in the field of tissue engineering and regenerative medicine. The aim of this study was to test the potential of the human stem cells of apical papilla (SCAP) to attach, proliferate and differentiate on a polycaprolactone (PCL)-based scaffolds. SCAP were extracted from the root apical papillae of freshly extracted immature premolar teeth by using enzymatic digestion. Porous PCL scaffolds were fabricated using particle leaching method and NaCl or mannitol as porogens. SCAP of passage 3 were seeded on non-porous and porous PCL scaffolds for up to 14 days. For control, cells were cultured on glass coverslips. Picogreen DNA quantification was used to assay for cell proliferation. Cell differentiation and development of calcification nodules were examined using scanning electron microscopy and alizarin red staining. SCAP showed a comparable attachment, growth and proliferation patterns on PCL scaffolds and coverslips. Cell proliferation was enhanced on mannitol scaffolds at all time points. Calcification nodules were detected in all PCL scaffolds while it was not present on glass coverslips. These nodules were detected on NaCl-scaffolds by day 7 and on mannitol and non-porous scaffolds by day 14. In conclusion, SCAP were able to attach, proliferate and differentiate on PCL scaffolds without using any inductive media, indicating their potential application for dental tissue regeneration.

Biodegradable scaffolds are useful tools in the field of tissue engineering and regenerative medicine. The aim of this study was to test the potential of the human stem cells of apical papilla (SCAP) to attach, proliferate and differentiate on a polycaprolactone (PCL)-based scaffolds. SCAP were extracted from the root apical papillae of freshly extracted immature premolar teeth by using enzymatic digestion. Porous PCL scaffolds were fabricated using particle leaching method and NaCl or mannitol as porogens. SCAP of passage 3 were seeded on non-porous and porous PCL scaffolds for up to 14 days. For control, cells were cultured on glass coverslips. Picogreen DNA quantification was used to assay for cell proliferation. Cell differentiation and development of calcification nodules were examined using scanning electron microscopy and alizarin red staining. SCAP showed a comparable attachment, growth and proliferation patterns on PCL scaffolds and coverslips. Cell proliferation was enhanced on mannitol scaffolds at all time points. Calcification nodules were detected in all PCL scaffolds while it was not present on glass coverslips. These nodules were detected on NaCl-scaffolds by day 7 and on mannitol and non-porous scaffolds by day 14. In conclusion, SCAP were able to attach, proliferate and differentiate on PCL scaffolds without using any inductive media, indicating their potential application for dental tissue regeneration.

Similar to other disciplines of advanced dentistry, a clinician may encounter complications or unforeseen circumstances during endodontic therapy. Every clinician performing endodontic procedures would have experienced a range of outcomes ranging from a case well done to an unfavorable prognosis related to a procedural accident. Examples of complications during the root canal procedure include ledge formation, separated instruments, and over-instrumentation. However, fear of procedural accidents should not deter a practitioner from performing root canal treatment. An experienced clinician uses knowledge, clinical skill and acumen, experience, and awareness of his or her own limitations to minimize these accidents.

Article Title and Bibliographic Information Double-blind Randomized Placebo-controlled Clinical Trial of Efficiency of Nonsteroidal Anti-inflammatory Drugs in the Control of Post-endodontic Pain. Elzaki WM, Abubakr NH, Ziada HM, Ibrahim YE . J Endod 2016;42(6):835-42 . Source of Funding No source of funding was identified. The study was conducted by the faculty of the Dentistry Department, University of Khartoum and the Khartoum Teaching Hospital emergency clinic Type of Study/Design Double-blind randomized controlled trial

Objective: To investigate variations in the root canal morphology of mandibular first premolars in a population from the United Arab Emirates using micro-computed tomography (micro-CT) and conventional radiography. Materials and Methods: Three-dimensional images of 50 extracted human mandibular first premolars were produced using a micro-CT scanner, and conventional radiography was also used to record the number of roots, the root canal system configuration, the presence of a C-shaped canal system and lateral canals, intercanal communications, and the number and location of apical foramina. The interpretations of micro-CT and conventional radiography were statistically analyzed using Fisher's exact test. Results: Variable root canal configurations based on Vertucci's classification were observed in the teeth (i.e., types I, III, IV, V, and VII). The examined teeth exhibited the following 2 additional root canal configurations, which did not fit Vertucci's classification: type 1-2-3 and type 1-3. A C-shaped canal configuration was present in 14 (28%) cases, and lateral canals were present in 22 (44%) cases. Apical deltas were found in 25 (50%) cases, intercanal communications were seen in 6 (12%) cases, and apical loops were seen in 2 (4%) of the samples. Micro-CT and X-ray imaging identified 39 (78%) and 34 (68%) apical foramina, respectively. A single apical foramen was detected in 33 (66%) samples, and 2 or 3 apical foramina were detected in 14 (28 %) and 3 (6%) samples, respectively. In 18.5 (37%) samples the apical foramina were located centrally, and in 31 (62%) they were located laterally. Conclusion: A complex morphology of the mandibular first premolars was observed with a high prevalence of multiple root canal systems.

Chogle SMA, Duhaime CF, Mickel AK, Shaikh S, Reese R, Bogle JH, Chan DK, Potluri S, Qutubuddin S. Preliminary evaluation of a novel polymer nanocomposite as a root-end filling material. International Endodontic Journal, 44, 1055–1060, 2011. Abstract Aim To evaluate two nanoparticle-enhanced polymer root-end filling materials (NERP1 and NERP2) on the initial apical seal as compared to a polymer-based commercial compomer. Methodology One hundred and forty extracted roots with completely formed apices were resected 3 mm from the apex. Cavities were then prepared in the apical openings of the resected root ends using an ultrasonic handpiece to a depth of 3 mm. The roots were then randomly divided into five groups to receive one of five root-end filling materials. Roots in groups 1 and 2 received NERP1 and NERP2, whilst those in groups 3 and 4 received identical polymers as groups 1 and 2 but without nanoparticle addition (RP1 and RP2, respectively). The root-end cavities for the fifth group were filled with commercially available root-end filling compomer. Roots were mounted in a dual-chamber leakage apparatus and inoculated coronally with Enterococcus faecalis. Turbidity of the apical broth was assessed daily for 4 weeks as a sign of initial leakage. The results were statistically analysed using odds ratio and Fisher’s chi-square analysis. Results Nanoparticle-enhanced root-end filling polymer 1 displayed significantly fewer leaked samples compared to all other tested groups as early as 5 days, whilst NERP2 was not significantly different compared to other groups. Odds ratio analysis revealed leakage of the commercial compomer was 12 times more likely than NERP1. Conclusion Nanoparticle-enhanced root-end filling polymer 1 can reduce apical microleakage significantly under laboratory conditions.

Advances have been made in identifying dental stem cells and their differentiation potential. Five different types of dental stem cells have been isolated from dental soft tissues: dental pulp, apical papilla, dental follicle and periodontal ligament. The characteristic features of these cells have been explored. They express various arrays of biomarkers including those specific for mesenchymal and/or embryonic stem cells. In vitro and in vivo studies have revealed that these stem cells varied in their proliferation and differentiation potential. Recent studies have demonstrated their wide range of plasticity and their potential use for regenerative medicine and dentistry. This article summarizes information available on the different types of dental stem cells and discusses their potential use in regenerative medicine.

A complete medical and dental evaluation is imperative following traumatic dental injuries, which are emergent situations that need a quick assessment and appropriate management. The proper diagnosis and treatment rendered determines the prognosis of the case. Proper documentation is important for medicolegal reasons and for baseline reference regarding the traumatic injury. Future treatment modalities and outcomes can be better managed with accurate documentation at the initial assessment.

The master apical preparation size in root canal therapy is debatable despite considerable research. The present study compared file sizes that bind at the apex before and during crown-down preparation and assessed the relation between apical size and extent of intracanal bacterial load. There were 100 single-rooted teeth biomechanically prepared after inoculation with Enterococcus faecalis. Canals were preflared, and apical size was ascertained by the first file to bind (FAB) at the working length (WL). During crown-down preparation, the first crown-down file to reach the apex during instrumentation was noted (CDF). Teeth were then divided into three master apical file size groups of CDF + 1, CDF + 2, and CDF + 3. Positive controls were inoculated postinstrumentation, whereas negative controls were instrumented without inoculation (n = 5). The samples were then cultured for intracanal bacterial counts. Fifteen samples and four controls were analyzed under SEM. The data were analyzed using ANOVA, Student's t-test, and chi(2) tests. The CDF was demonstrated to be an average of four file sizes larger than the FAB (p0.05). There was a significant increase in the number of samples with negative cultures from CDF + 1 to CDF + 3. SEM observation revealed bacteria on dentinal walls and in tubules even in most negative canal cultures.

A conducting media is necessary when using an electric pulp tester (EPT). The objective of this study was to observe differences in conductance through various media. We hypothesized that variations in current conductance through different media exist. The pulp chamber of a freshly extracted premolar was exposed, and the cathode of a voltmeter was inserted into the pulpal tissue. The anode was coupled to the EPT handpiece. The measurement taken during dry (no interface media) EPT tip-to-tooth contact was 0 V, which served as negative control. EPT tip directly touching the cathode measured 3.9V and served as positive control. A number of media readily available in the dental office were tested. Data was analyzed using single factor ANOVA. Listerine (3.3) conducted the most voltage (p

The purpose of this study was to test the ability of a commercially available iodoform gutta-percha, to delay infiltration of Enterococcus faecalis using a microleakage model. Seventy extracted single-rooted teeth were decoronated and biomechanically prepared using hand and rotary instruments. Thirty roots were obturated laterally with iodoform gutta-percha and another 30 with regular gutta-percha. Both groups were suspended in sterile BHI broth. An inoculum of E. faecalis suspension was placed at the coronal end of each root, incubated and replenished daily. The apical broth was observed for turbidity, indicating bacterial microleakage. Samples were observed for 32 days, and data was analyzed to compare microleakage between the two groups. The results showed no significant difference between the iodoform and regular gutta-percha samples in delaying microleakage of E. faecalis (p > 0.05).

Nanosized particles such as clusters of small numbers of atoms or molecules in nanostructured biomaterials used in biomedical research have demonstrated significantly superior properties from the properties of the same material at larger scales of measurement. This concept is influencing each and every branch of science and endodontics is no exception. Although in its nascent stage, research into the applications for nanotechnology has been initiated in several treatment areas in endodontics. The superior resistance of nanomaterials to wear and fatigue is being suggested for surface modifications of currently used rotary nickel–titanium files for root canal therapy. Irrigants, medicaments, sealers, and obturating materials may be enhanced using nanoparticles and drug elutions to help improve disinfection and sealing of the root canal system. Applications in regenerative endodontics are currently underway creating improved scaffolds and growth-factor delivery. This chapter reviews current scientific knowledge and research findings as well as feasible and predictable future applications of nanobiomaterials in the field of endodontics.

To compare the adherence of Prevotella melaninogenica and Enterococcus faecalis to 3 guided tissue regeneration membranes: Atrisorb, Lambone, and OsseoQuest. It was hypothesized that OsseoQuest would show increased bacterial adherence compared to Lambone and Atrisorb.The barriers were suspended in trypticase soy broth containing an inoculum of either P melaninogenica or E faecalis. The samples were incubated under appropriate conditions for 6, 24, and 48 hours. Following incubation, each membrane was mixed in fresh media in a vortex machine to dislodge adherent bacteria. The vortexed media was quantitatively assessed using serial dilutions for viable cell count.E faecalis exhibited higher adherence compared to P melaninogenica with time. Of the membranes tested, Lambone displayed the least bacterial adherence.An analysis of the results indicated that bacterial adherence was time-dependent for all membranes. Membrane structure, chemical configuration, hydrophobicity, and bacterial cell surface structure were suggested as factors contributing to variance in bacterial adherence.

This study sought to assess setting time and sealing properties of intracanal mineral trioxide aggregate (MTA). Eighty-three extracted single-rooted human teeth were decoronated and instrumented using the crown-down technique. The apical 3.0 mm of each tooth was resected. After MTA was placed, the coronal openings of the canals were sealed with moist cotton pellets. Root samples were divided into three groups according to setting time periods of four hours, two days, or one week. Within each group, 15 samples were kept in wet gauze to provide a moist apical environment (WA) while the remaining 10 were kept in a dry apical environment (DA). After respective incubation periods, 20 samples per group (10 WA, 10 DA) were mounted in an apical broth turbidity determination chamber and incubated for 30 days. The remaining five teeth per group (WA-h) were sectioned into 3.0 mm slices and compared for MTA setting hardness using the Shore-D Hardness test. Remaining teeth served as negative and positive controls. Each sample was inoculated coronally with Enterococcus faecalis and checked daily for turbidity in apical broth. Microbial leakage was reduced significantly as setting time increased from four hours to two days or one week. There was no significant reduction in leakage when setting time was increased from two days to one week. Over the first 20 days, the DA samples showed a higher rate of leakage compared to the WA samples. The Shore-D hardness test correlated with leakage results; 93% of total setting hardness was reported at two days and one week compared to only 75% for the four-hour group. Results suggest that apical moisture may affect MTA setting time or sealing ability initially and that intracanal MTA may take up to two days to set completely.

The success of endodontic therapy is based on a number of criteria, particularly the conservation of tooth structure. This principle requires a systematic approach to pulp chamber access. By correlating the occlusal anatomy with the location of the root canal orifice, a dentist may find a number of guidelines for improving access design. In this in vitro study, the authors evaluated 29 human maxillary first molars. Digital radiographs and digital occlusal photographs were taken of each specimen before and after decoronation at the cementoenamel junction (CEJ). The three images were superimposed on one another and evaluated for occlusal and pulpal patterns. The thickness of the pulp chamber walls of the CEJ varied, based on the circumference of individual teeth. In addition, the canal orifices at the pulp chamber floor exhibited a consistent pattern relative to the cusp tips, which may assist in access design.

Many parameters must be addressed for endodontic therapy to succeed. Because conservation of tooth structure is vital, the pulp chamber and root canal orifices should be located by using a method that is consistent yet accurate. The correlation of occlusal anatomy with the locations of the root canal orifice may aid dentists with access design. This study sought to determine if a correlation existed between occlusal surface anatomy, pulp chamber location, and root canal orifice location. This in vitro study utilized 21 human mandibular first molars. For each specimen, amalgam restorations were placed in the respective cusp tips, with gutta-percha placed in each canal at the level of the furcation. The authors made digital radiographs and occlusal photographs of each complete specimen. The samples were sectioned horizontally at the level of the cementoenamel junction (CEJ). Using a digital software program, the radiographs were superimposed with the digital photographs and correlations of pulp chamber to locate the canal orifice and occlusal surface anatomy. The authors found that the pulp chamber of the mandibular first molar lies more lingual at the level of the CEJ. In addition, the orifices were consistent in their location relative to cusp tip anatomy, a discovery that may assist dentists with the access design.

A descriptive, cross sectional survey was developed to determine the preferences of endodontists when prescribing analgesics. Eleven clinical scenarios describing common endodontic diagnoses or procedures with specified severity of pain were provided. A survey was sent to 310 AAE members and 63 responded, providing a 20% response rate. Respondents were given various choices for analgesic prescription including various dosages of ibuprofen or acetaminophen (APAP), or combination narcotic medications. Data were analyzed by chi2 tests. Non-narcotics were preferred over narcotics for all clinical situations. Significantly more respondents selected ibuprofen 600 mg (4x a day) regardless of the severity of preoperative or postoperative pain (p

Enterococcus faecalis has been shown to be highly resistant once established in the root canal system and may play an important role in endodontic failures. The purpose of this study was to evaluate the antimicrobial activity of four root canal sealers on E. faecalis. Seventeen blood-agar plates were inoculated with E. faecalis using the Lawn technique. Five discs were placed on each plate, four with sealers--Sealapex, Roth 811, Kerr EWT, and AH-Plus--and an ampicillin disc as the control. The plates were incubated at 37 degrees C. The zones of inhibition were measured at 24 and 48 h. Analysis using a one-way ANOVA and Tukey test showed a statistically significance difference (p < 0.05) between all four groups of sealers. Roth 811 showed the largest zone of inhibition (1.1 mm), followed by Sealapex (0.8 mm) and Kerr EWT (0.5 mm), whereas AH-Plus had no antimicrobial activity. There was no difference in the zones of inhibition between the 24- and 48-h time periods.

The inhibition of growth of Prevotella nigrescens and Enterococcus faecalis by three barriers membrane, (a) polytactic acid (Atrisorb®), (b) laminar bone, and (c) calcium sulfate, was compared using an agar diffusion test. The first group of 20 plates were inoculated with P. nigrescens in a prereduced anaerobically-sterilized brain-heart infusion broth, while the second group of 20 plates were inoculated with E. faecalis in a brain-heart infusion broth. On each plate, a 5.0-mm section of each barrier was placed such that every plate had all three barriers. The plates in the P. nigrescens group were incubated in an anaerobic chamber for 7 days. The plates in the E. faecalis group were incubated at 37°C for 2 days. No zones of inhibition were observed with laminar bone or calcium sulfate. Zones of inhibition were observed with the Atrisorb® barrier membrane in both groups. The zone of inhibition of P. nigrescens was significantly greater than the zone of inhibition of E. faecalis . The hydrophobicity of Atrisorb® and its N-methyl-2-pyrolidine component were suggested as the sources of its antibacterial activity.

It has been found that Enterococcus faecalis is most commonly isolated in failed endodontic treatment. Irrigation with chlorhexidine gluconate has been suggested based on its antimicrobial effect and substantivity. Calcium hydroxide also is an effective antimicrobial agent because of its high alkalinity. The purpose of this study was to test the individual and combined effect of calcium hydroxide and chlorhexidine against E. faecalis . The agar-diffusion test was performed on Mueller-Hinton plates. Paper disks were impregnated with: (a) CaOH powder with sterile water; (b) Pulpdent®; (c) 0.12% Peridex®; (d) CaOH powder with Peridex®; and (e) Pulpdent® with Peridex®. Ampicillin served as a control. The plates were incubated at 37°C for 72 h. Peridex® showed significantly larger zones of inhibition compared with CaOH. No statistically significant difference was found between Peridex® and the combination of CaOH and Peridex®.

The objective of this study was to evaluate the antimicrobial activity of stannous fluoride, calcium hydroxide, or the two in combination against Enterococcus faecalis. Fifteen Mueller-Hinton agar plates were used to conduct a disc diffusion susceptibility test. The plates were inoculated with E. faecalis. The groups tested were: (a) stannous fluoride (Stanimax); (b) calcium hydroxide; and (c) a combination of stannous fluoride and calcium hydroxide. Three filter paper discs, each soaked with one of the groups, were placed along with an antibiotic control (ampicillin) on each agar plate. The plates were then incubated at 37 degrees C. The zones of inhibition were measured at 24 and 48 h. One-way ANOVA revealed a statistically significant difference (p0.05) between the three groups. Stannous fluoride displayed the widest zone (1.7 mm), followed by the combination of stannous fluoride and calcium hydroxide (1.1 mm), whereas calcium hydroxide by itself displayed a minimal zone of inhibition (0.05 mm).

NOTCH plays a role in regulating stem cell function and fate decision. It is involved in tooth development and injury repair. Information regarding NOTCH expression in human dental root apical papilla (AP) and its residing stem cells (SCAP) is limited. Here we investigated the expression of NOTCH3, its ligand JAG1, and mesenchymal stem cell markers CD146 and STRO-1 in the AP or in the primary cultures of SCAP isolated from AP. Our in situ immunostaining showed that in the AP NOTCH3 and CD146 were co-expressed and associated with blood vessels having NOTCH3 located more peripherally. In cultured SCAP, NOTCH3 and JAG1 were co-expressed. Flow cytometry analysis showed that 7%, 16% and 98% of the isolated SCAP were positive for NOTCH3, STRO-1 and CD146, respectively with a rare 1.5% subpopulation of SCAP co-expressing all three markers. The expression level of NOTCH3 reduced when SCAP underwent osteogenic differentiation. Our findings are the first step towards defining the regulatory role of NOTCH3 in SCAP fate decision.