Influence of provisional cementation on the stability of adhesively bonded resin-based composite crowns.

PURPOSE: To investigate the influence of temporary cementation and subsequent bonding on the durability during in-vitro aging-simulation and fracture force of resin-based composite crowns. METHODS: Identical molar crowns (n=48, n=8 per group) were milled from resin-based composites and temporarily cemented and finally bonded to human molars. To simulate temporary application, crowns were cemented either with zinc-oxide-eugenol-cement (Tempbond) or with eugenol free zinc-oxide-cement (Tempbond NE). For a first simulation of a long-term provisional clinical application, thermal cycling, and mechanical loading (TCML 2 x 600 x 5°C-55°C, 2 minutes each cycle, distilled water, 240,000 cycles at 50N) was performed. After TCML all crowns were removed, cleaned, and luted either by using etch-and-rinse technique (Vococid, Futurabond U, Bifix QM) or a self-adhesive (Bifix SE) cementation system. A second thermal cycling and mechanical loading (TCML 2 x3,000 x 5°C/55°C, 2 minutes each cycle, distilled water, 1.2 x 106 at 50N) was accomplished to simulate 5 years of clinical application. To assess the survival of the crowns, the failure rates during TCML were documented. As controls, crowns were included without prior provisional cementation. After TCML all crowns were loaded to failure. Failure was categorized as fracture of the crown and partial loosening of the crown. RESULTS: All crowns survived both TCML procedures without any failures. The fracture values after TCML varied between 3,538.0 ± 1,041.2 N and 4,612.0 ± 801.5 N without significant (P= 0.146) differences between the individual groups. No correlation was found between fracture force and type of provisional cementation (zinc-oxide-eugenol vs. zinc-oxide: Pearson: -0.063/P= 0.672) or type of bonding (adhesive vs. self-adhesive: Pearson: -0.151/ P= 0.307). No different failure pattern was observed between the tested systems. CLINICAL SIGNIFICANCE: Regardless of the type of temporary cementation, there was no effect on the in-vitro performance or strength of the final permanently bonded crowns. Resin-based crowns might be bonded with adhesive or self-adhesive systems even after previous temporary cementation.

Evaluation of compressive strength, microhardness and solubility of zinc-oxide eugenol cement reinforced with E-glass fibers.

BACKGROUND: Zinc-oxide eugenol (ZOE) cements are among the most used temporary materials in dentistry. Although ZOE has advantages over other temporary fillers, its mechanical strength is weaker, so researchers are working to improve it. E-glass fibers have emerged as promising reinforcing fibers in recent years due to their strong mechanical behavior, adequate bonding, and acceptable aesthetics. OBJECTIVES: To evaluate and compare the compressive strength, surface microhardness, and solubility of the ZOE and those reinforced with 10 wt.% E-glass fibers. METHODS: A total of 60 ZEO specimens were prepared; 30 specimens were reinforced with 10 wt.% E-glass fibers, considered modified ZOE. The characterization of the E-glass fibers was performed by XRF, SEM, and PSD. The compressive strength, surface microhardness, and solubility were evaluated. Independent sample t-tests were used to statistically assess the data and compare mean values (P ≤ 0.05). RESULTS: The results revealed that the modified ZOE showed a significantly higher mean value of compressive strength and surface microhardness while having a significantly lower mean value of solubility compared to unmodified ZOE (P ≤ 0.05). CONCLUSION: The modified ZOE with 10 wt.% E-glass fibers had the opportunity to be used as permanent filling materials.

Zinc oxide-ozonated olive oil as a new root canal filling material in primary molars: a clinical randomized controlled trial.

OBJECTIVES: The complex root canal anatomy of primary teeth keeps it very tricky to attain appropriate cleansing by biomechanical instrumentation, so obtaining an obturating material with excellent antimicrobial properties is a challenge in current clinical pulpectomy practice. So, this study aimed to assess the clinical and radiographic performance of zinc oxide-ozonated olive oil as a primary root canal filling material. MATERIALS AND METHODS: Ninety non-vital primary molars in children ranging from 4 to 8 years were allocated into three groups in which root canals were filled with zinc oxide-ozonated olive oil, zinc oxide-olive oil, and zinc oxide-eugenol (ZOE) according to each group after pulpectomy procedure. Clinical and radiographic evaluations were done at 3-, 6-, and 12-month follow-up periods. Statistical analysis was performed for the collected data. RESULTS: All study groups showed a significant improvement regarding clinical signs and symptoms during follow-up periods. Ozonated-olive oil group revealed a significant increase in furcation radiodensity and a decrease in periodontal ligament space at 3-, 6-, and 12-month follow-up intervals compared to other groups. CONCLUSION: Zinc oxide-ozonated olive oil and zinc oxide-olive oil paste had shown good clinical and radiographic success for primary teeth pulpectomy. CLINICAL RELEVANCE: The intricate torturous primary root canal anatomy, in addition to the child's negative behavior, interferes with the complete debridement, so the long-lasting antibacterial effect of the primary root canal filling material aids in the pulpectomy success.

Lesion sterilization and tissue repair with chloramphenicol, tetracyline, zinc oxide/eugenol paste versus conventional pulpectomy: A 36-month randomized controlled trial.

BACKGROUND: Endodontic treatment of primary molars represents one of the challenges in pediatric dentistry. There is a lack of consensus in the literature about the endodontic techniques and filling paste for primary teeth with pulp necrosis. AIM: To compare the effectiveness of the LSTR technique (lesion sterilization and tissue repair) with CTZ paste (chloramphenicol, tetracycline, zinc oxide and eugenol) and pulpectomy with ZOE paste (zinc oxide and eugenol) in the treatment of primary molars with pulp necrosis. DESIGN: Eighty-eight primary molars with pulp necrosis from 70 children between the ages of 3 and 8 years were included. The teeth were randomized to the LSTR with CTZ paste group or pulpectomy with ZOE paste group. Clinical and radiographic evaluations were performed at 18, 24, 30 and 36 months. RESULTS: At 36 months, clinical success was 86.4% in LSTR with CTZ paste and 90.9% in pulpectomy with ZOE paste (p = .45). Radiographic success was 43.2% in both groups (p = 1.00). The overall success was 40.9% in LSTR with CTZ paste and 43.2% in pulpectomy with ZOE paste (p = 1.00). CONCLUSION: After 36 months of evaluation, the effectiveness of the LSTR technique with CTZ paste and pulpectomy with ZOE paste was similar for the treatment of primary molars with pulp necrosis.

Clinical and Radiographic Evaluation of Various Herbal Products Used with Zinc Oxide as an Obturating Material in Primary Teeth: An In Vivo Study.

AIM: To compare the clinical and radiographically mixture of zinc oxide with Aloe vera, Curcumin and neem as an obturating material for pulpectomy. MATERIALS AND METHODS: The study comprised of age group 4-8 years children requiring endodontic treatment for at least a single primary molar tooth. Sixty primary molar teeth from 43 children were divided equally and randomly into four study groups. The materials used for obturation were zinc oxide powder (ZnO) and Eugenol (ZOE) (group I), ZnO and Aloe vera Gel (group II), ZnO and Curcumin Powder (group III), ZnO and neem extract (group IV). They were evaluated clinically and radiographically at immediate postoperative and then at 1-, 3-, 6-, and 9-month intervals. RESULTS: At the end of 9 months, the Chi-square test revealed 100% success rate for recovery of pain in group I and III, 66.66% in group II and 93.3% in group IV. The success rates for absence of abscess and for periradicular radiolucency in group I, III, and group IV were 100% and 66.6% for group II. The success rate for periapical radiolucency in group I and group III was 100%, in group II 66.6% and in group IV 93.35%. The success rate for all the groups shows 100% success in terms of pathological root resorption. CONCLUSION: Zinc oxide eugenol has proven to be the best obturating material. ZnO with Aloe vera showed a success rate which is significantly lower than the other medicaments. ZnO with Curcumin and ZnO with neem had shown promising clinical and radiographical results. CLINICAL SIGNIFICANCE: ZnO with Curcumin and ZnO with neem can be used as a root canal filling material in primary teeth with further follow-up studies.

Efficacy of an iodoform-based filling material for pulpectomy of primary teeth: A 24-month non-inferiority randomized clinical trial.

AIM: The aim of this non-inferiority randomized clinical trial was to compare the efficacy of an iodoform-based paste (Guedes-Pinto -(GP)) as a filling material in pulpectomies of primary teeth, and a standard material composed by calcium hydroxide and iodoform (CaOH/Iodof paste; Vitapex® ). DESIGN: A total of 104 teeth from 61 children (3-8 years old) were randomly allocated to two groups according to filling materials. Children were followed up for 24 months. The primary endpoint was the treatment success rate evaluated through clinical and radiographic examinations at follow-up, and the secondary outcome was the analysis of the canal filling quality. Differences in the proportion of treatment success was calculated based on 95% confidence intervals (95% CI) and with the Miettinen and Nurminen method in the intention-to-treat population, considering a -20% of the non-inferiority limit. RESULTS: From 104 randomized teeth, 102 were followed up after 24 months (attrition rate of 1.9%). The success rate of teeth treated with the GP paste was 86.8% (95% CI: 69.9-94.9) and 78.4% (95% CI: 61.8-89.1) with the CaOH/Iodof paste. Consequently, a non-inferiority of the GP paste was observed when compared to the CaOH/Iodof paste (P < .001). CONCLUSION: The GP paste has a non-inferior success rate than the CaOH/Iodof paste used as filling material for pulpectomy in primary teeth.

The evaluation of cytotoxicity and cytokine IL-6 production of root canal sealers with and without the incorporation of simvastatin: an invitro study.

BACKGROUND: Freshly mixed root canal sealers when proximate the periapical tissues, trigger varying degrees of cytotoxicity/inflammatory reactions. Simvastatin, a class of the drug statin, is a widely used cholesterol-lowering agent with additional anti-inflammatory activities. This study assessed the effects of simvastatin on cytotoxicity and the release of IL-6 (Interleukin-6) production when incorporated in zinc oxide eugenol and methacrylate resin-based sealers. METHODS: Experimental groups consisted of conventional zinc oxide eugenol and methacrylate based-EndoREZ sealers (ZE & ER respectively) and 0.5 mg/mL simvastatin incorporated sealers (ZES & ERS). L929 mouse fibroblast cells were exposed to freshly mixed experimental sealers and evaluated for cytotoxicity (MTT assay) and inflammation levels (inflammatory marker IL-6 for ELISA) at various time intervals (0h, 24h and 7th day). The values were compared to the cell control (CC; L929 cells alone) and solvent control (SC; L929 cells + DMSO) groups. All the experiments were conducted in triplicates and subjected to statistical analysis using IBM SPSS Statistics software. Non parametric tests were conducted using Kruskal-Wallis and Friedman tests for inter-group and intra-group comparisons respectively. Pairwise comparison was conducted by post hoc Dunn test followed by Bonferroni correction. P values < 0.05 were considered statistically significant. RESULTS: All the experimental groups (ZE, ER, ZES, ERS) exhibited varying degree of cytotoxicity and IL-6 expression compared to the control groups CC and SC. The cell viability for ZE and ER decreased on day 7 as compared to 24 h. ZES and ERS had higher viable cells (75.93% & 79.90%) compared to ZE and ER (54.39% & 57.84%) at all time periods. Increased expression of IL-6 was observed in ZE & ER (25.49 pg/mL & 23.14 pg/mL) when compared to simvastatin incorporated ZE & ER (ZES-12.70 pg/mL & ERS-14.68 pg/mL) at all time periods. Highest level of cytotoxicity and inflammation was observed in ZE compared to all the other groups on day 7. CONCLUSIONS: Addition of 0.5 mg/mL of simvastatin to the sealers (ZES and ERS) decreased the cytotoxicity in the freshly mixed state and reduces their inflammatory effect.

The effect of mechanical and chemo-mechanical temporary cement cleaning methods on shear bond strength with self-adhesive resin cement (an in-vitro study).

BACKGROUND: Adhesive tooth-colored restorations are strongly dependent on the substrate surface cleanliness to allow intimate contact between resin cement and dentin surface, so several methods were adopted for the total cleaning of temporary cement residues. This study aimed to assess the effect of mechanical and chemo-mechanical cleaning methods of temporary cement on the immediate shear bond strength of self-adhesive resin cement to dentin surface. METHODS: Forty freshly extracted lower first premolars were cut to expose a flat dentin surface. Discs of temporary crown composite resin material were constructed and cemented to the flat dentin surface using resin-based and non-eugenol temporary cement then stored at room temperature in distilled water. Dividing of samples into two groups according to the method of temporary cement cleaning. Group I (n = 20) mechanical cleaning using the rotary instrument, and group II (n = 20) chemo-mechanical cleaning using chlorhexidine-containing scrub. CAD/CAM reinforced Composite discs were bonded to the dentin surface using self-adhesive composite resin cement, then measurement of shear bond strength was done using a universal testing machine. Further analysis of failure mode after debonding was performed by Scanning electron microscope. RESULTS: No statistically significant difference was found between the mean shear bond strength of the two cleaning methods (P-value = 0.636). Regardless of the cleaning method, the group cemented with resin-based temporary cement showed statistically significantly higher mean shear bond strength than non-eugenol temporary cement (P-value = 0.048). CONCLUSION: Both cleaning methods (mechanical and chemo-mechanical) applied in this study were effective in cleaning temporary cement remnants from the dentin substrate surface with statistically significant differences between results of shear bond strength with significantly higher values recorded with resin-based temporary cement.

A Comparative Analysis of Voids and Sealing Ability of Different Obturating Techniques Using CBCT.

AIM: To evaluate voids and sealing ability using a disposable syringe, endodontic pressure syringe, and Skinni syringe with NaviTip in primary molars with cone-beam computed tomography (CBCT). MATERIALS AND METHODS: The 15 extracted primary mandibular molars with at least one root ≥8 mm length and an equal number of mesiobuccal canals were divided into three groups, i.e., obturation using a disposable syringe, an endodontic pressure syringe, and a Skinni syringe with NaviTip, respectively. The evaluation of the apical seal was determined as the measurement between the apical end of the filling material and the radiographic apex. The quality of the filling was determined by the size, number, type, and location of voids present. Statistical analysis was done using the Chi-square test and post-hoc test. RESULTS: The endodontic pressure syringe score was the highest and statistically significant in obtaining apical seal (p = 0.013). Disposable syringe shows highest size of voids (p = 0.01) in which type I-voids (p = 0.04) and type S-voids (p = 0.07) were statistically significant. The location of voids was maximum at the middle third of the root (p = 0.016). CONCLUSION: The endodontic pressure syringe provided the best root canal obturation of primary molars, whereas the disposable syringe was least effective with the maximum number and size of voids. CLINICAL SIGNIFICANCE: Comparing the voids and sealing abilities of different obturating techniques with CBCT would help the pediatric practitioners for better outcome of obturation in primary teeth.

Cytocompatibility of filling pastes by primary teeth root simulating model.

Evaluate the cytocompatibility of Calen®/ZO, Calcicur®, Vitapex®, Endoflas®, and zinc oxide/eugenol-based (ZOE) root canal pastes (RCP) to human primary osteoblasts (HPO) through a simplified model for primary teeth. The model employed pipette tips filled with 0.037 g of paste, exposed to 185 µL of culture medium for 24 h (n = 6). Release of components was analysed by Proton Nuclear Magnetic Resonance Spectroscopy (1H-NMR). HPO were exposed to conditioned media for 24 h. Cell viability was assessed by cell density and metabolic activity, and release of interleukin 6 (IL-6), vascular endothelial growth factor (VEGF) and fibroblast growth factor (bFGF) by immunological assay. Physicochemical properties and antimicrobial efficacy were also evaluated. 1H-NMR spectra analysis showed similarity between ZOE, Endoflas®, Calcicur®, and Vitapex® compared to Calen®/ZO and positive control, which showed distinct released components. Calen®/ZO and Calcicur® exhibited high alkaline pH in all periods and showed similar solubility. Calen®/ZO, ZOE, and Vitapex® showed similar flow rate. Calen®/ZO, Calcicur®, and Vitapex® did not exhibit antimicrobial efficacy. Calen®/ZO presented cytotoxicity (p < 0.05). Pastes did not increase IL-6 release compared to control. Apart from Vitapex®, all pastes significantly induced VEGF/bFGF release. Interactive effects among released products may affect biological response to filling pastes. Calcicur®, ZOE, Endoflas® and Calen®/ZO presented good to moderate cytocompatibility, with low impact on pro-inflammatory cytokine release and induction of growth factors of interest to tissue repair. This simplified model, specific for the evaluation of the cytocompatibility of RCPs on primary teeth, suggests how these pastes might contribute to bone repair in clinical situations of apical periodontitis in children.

Treatment Outcomes of Pulpectomy in Primary Maxillary Incisors Filled with ZOE and Metapex: A Two-year Retrospective Study.

OBJECTIVES: To address a literature gap by evaluating, in a larger set of samples, the clinical and radiographic outcomes of pulpectomy in primary maxillary incisors using ZOE and calcium hydroxide/iodoform paste. To also identify the predisposing factors for treatment outcomes. STUDY DESIGN: Medical charts of 124 patients (aged 16 to 60 months) and radiographs of their incisors (309 incisors) were reviewed (128 with ZOE and 181 with Metapex). All incisors were restored with composite resin crowns. RESULTS: The radiographic success rates for ZOE and Metapex were: 85.9% and 82.9% at the 12-month recall, and 69.2% and 64% at the 24-month recall, with no statistically significant difference between the two groups. Clinical failures occurred more frequently in the Metapex group (P = 0.006), as clinical signs of pain and soft tissue pathosis were found in 6.2% of the Metapex cases at 24 months but none in the ZOE group. Significant predisposing factors for radiographic success were type of tooth, degree of obturation at recalls, and preoperative root resorption. CONCLUSIONS: The radiographic success rates are comparable between the ZOE and Metapex groups. Clinical pathological manifestations such as pain and soft tissue pathosis are seen in the Metapex group at recalls, but none in the ZOE group. Predisposing factors such as type of incisor, preoperative root resorption, and extent of filling at recalls are associated with the radiographic success rate.

Are different pulp treatment techniques and associated medicaments effective for the treatment of extensive decay in primary teeth?

Data sources Cochrane Oral Health's Trials Register and Central Register of Controlled Trials, Medline Ovid, Embase Ovid, Web of Science, Open Grey, US National Institutes of Health Ongoing Trials Register and World Health Organisation International Clinical Trials Registry Platform. There were no restrictions on language or publication dates.Study selection Two reviewers selected randomised clinical trials (RCTs) comparing different pulp interventions in extensively decayed primary teeth, which combined a pulp treatment technique and a medicament.Data extraction and synthesis Data were extracted independently by two reviewers recording year of publication, country of origin, inclusion/exclusion criteria, description of interventions, sample size, mean age, duration of follow-up and outcome data. Risk of bias was assessed by two reviewers. Meta-analysis was performed on RCTs comparing different medicaments for the same pulp technique or different pulp treatment techniques with each other.Results Eighty-seven RCTs were included in qualitative synthesis, yielding 59 studies for meta-analysis. The 87 RCTs involved 7,140 randomised teeth with 17 split-mouth RCTs and 70 parallel arm design. In total, 125 different comparisons were examined using clinical and radiological failure rates; 75 compared different pulpotomy agents or techniques, 25 compared different pulpectomy agents, four compared pulpotomy and pulpectomy, and 21 compared different agents for direct pulp capping. Where possible, data were compared for 6, 12 and 24 months. For pulpotomy, mineral trioxide aggregate (MTA) appears least likely to fail over those time periods. For pulpectomy, results were inconclusive comparing failure rates between various agents; however, two RCTs found a lower failure rate for zinc oxide-eugenol (ZOE) compared with Vitapex. For direct pulp capping, there was a low number of studies undertaking the same comparisons; calcium silicates (eg MTA and Biodentine) hold future promise.Conclusions Overall, evidence quality ranged from moderate to very low. For pulpotomy, MTA may be the best pulpotomy medicament in primary molars. Formocresol is effective but generally accepted as toxic. Biodentine, enamel matrix derivatives, laser application or Ankaferd Blood Stopper (a plant-based haemostatic agent used to control gastrointestinal bleeds) appear to be second choices. If all of these are unavailable, an application of sodium hypochlorite may be the safest option. For pulpectomy, evidence was inconclusive; however, ZOE paste may be more effective than Vitapex, but no further conclusions could be made. For direct pulp capping, the evidence was of low to very low quality. The best alternative may be a tricalcium silicate, especially MTA. Future RCTs may change these findings.

Antimicrobial Activity of Nano-Magnesium Hydroxide Against Oral Bacteria and Application in Root Canal Sealer.

BACKGROUND The goal of the present work was to assess the antibacterial activity of nano-magnesium hydroxide (NMH) against Streptococcus mutans (S. mutans) and to explore the antimicrobial function of AH Plus™ sealer incorporating NMH. MATERIAL AND METHODS The antimicrobial behavior of NMH against S. mutans was evaluated with bactericidal tests. A modified direct contact test was used to assess the antimicrobial activity of unset AH Plus containing NMH after 5 minutes, 20 minutes, and 60 minutes of contact with bacteria. The antimicrobial effects and the amount of surface-adhering bacteria of the solidified materials were explored by SEM and confocal laser scanning microscopy, respectively. RESULTS NMH powder presented excellent antimicrobial activity against S. mutans. Mg²âº and OH⁻ were not the main factors resulting in bacterial death. Approximately 93.1% and 98% of the S. mutans were killed in the AH Plus+7% NMH group after incubation for 5 minutes and 20 minutes, respectively. AH Plus with 5% or 7% NMH were more potent against S. mutans compared with AH Plus alone (P<0.05). Moreover, the antibacterial function of AH Plus was lost after setting. NMH enabled the solidified AH Plus to still have antibacterial properties on the seventh day. CONCLUSIONS NMH can be used to modify AH Plus sealer to eradicate residual bacteria and prevent reinfection.

Physico-chemical investigation of endodontic sealers exposed to simulated intracanal heat application: epoxy resins and zinc oxide-eugenols.

AIM: To gain information in a laboratory setting about the effect of thermal treatment of epoxy resin-based and zinc oxide-eugenol-based sealers. METHODOLOGY: AH Plus and Pulp Canal Sealer (PCS) were exposed to thermal treatment at 37, 47, 57, 67, 77, 87 and 97 °C for 30 s. According to clinically relevant considerations, intracanal sealer temperature is likely not to exceed 60 °C during warm vertical root canal filling. Heat application is recommended for less than 30 s during continuous wave technique, but might exceed this threshold in complex cases. Furthermore, heat treatment at 97 °C was performed for 60 and 180 s to simulate inappropriate implementation of warm vertical filling techniques. Specimens were heated inside 2-mL plastic tubes in a thermo-controlled water bath until the temperatures were reached and kept at this temperature for the determined period of time. Afterwards, specimens were cooled to body temperature and physical properties (setting time, flow, film thickness according to ISO 6876) were assessed. Chemical properties (Fourier transformed infrared spectroscopy) were assessed after complete setting of the specimens in an incubator at 37 °C and 100% humidity. Statistical analysis of physical properties was performed using Kruskal-Wallis test (P = 0.05). RESULTS: The setting time of AH Plus and PCS decreased when temperature and duration of heat application increased. Whilst the setting time of AH Plus decreased from 622 min at 20 °C (for 30 s) to 381 min at 97 °C (for 180 s; P < 0.05), heat treatment of PCS at 97 °C for 180 s led to an immediate setting of the material. From 20 °C (for 30 s) to 97 °C (for 30 s), the setting time of PCS decreased from 80.1 to 41.0 h (P < 0.05). Film thickness and flow were not relevantly influenced by thermal treatment except for PCS at 97 °C for 180 s. FT-IR spectroscopy did not reveal any chemical changes of either sealer after thermal treatment. CONCLUSIONS: Thermal treatment simulating clinically relevant temperature levels and heating times did not lead to any substantial physical or chemical changes at all temperature levels when heating did not exceed 60 s. AH Plus and Pulp Canal Sealer can be considered suitable for warm root filling techniques.

Transforaminal and systemic diffusion of an active agent from a zinc oxide eugenol-based endodontic sealer containing hydrocortisone-in an in vivo model.

OBJECTIVES: This study aimed to quantify in vivo the release of hydrocortisone acetate (HCA) contained in a zinc oxide eugenol-based endodontic sealer, in various tissues. MATERIALS AND METHODS: Roots of human teeth, shaped with One Shape single file and sealed with Endomethasone N, previously radiolabelled with tritium (3H-HCA), were implanted in the back of 24 mice. Mice were sacrificed at 2, 8, 24, and 48 h to evaluate and quantify the amount of radioactivity in subcutaneous tissues surrounding the apex (periapical-like) of the implanted teeth, blood, spleen, kidneys, liver, and urine. RESULTS: Radioactivity was released from the apex of the tooth into the periapical-like tissues with a peak measured at 2 h post-implantation (2.25% of the initial radioactivity/g). This quantity decreased significantly over time between 2 h and each time points. Radioactivity was still measured up to 48 h in the periapical-like tissues (0.42% of the initial radioactivity). The same pattern of kinetic was observed for all organs. The total quantity of radioactivity significantly decreased over time from 4.36% measured 2 h post-implantation to 0.74% at 48 h. Finally, about 10% of the initial radioactivity from Endomethasone N used to fill the root canal was retrieved after 48 h in the urine. CONCLUSIONS: This study demonstrated that radioactive-HCA from Endomethasone N can diffuse through the apex of the root canal and follow a classical pharmacokinetics. CLINICAL RELEVANCE: This mouse model shows that radioactive-HCA can diffuse through the apex and do not accumulate in periapical-like tissues and organs.

Investigating unset endodontic sealers' eugenol and hydrocortisone roles in modulating the initial steps of inflammation.

INTRODUCTION: Endodontic treatment success is achieved not only when the cement provides a hermetic seal but also when the injured periapical tissue is regenerated. However, an exaggerated inflammatory reaction hinders tissue regeneration and it has been shown that dental materials affect the inflammatory response through modulation of cytokine secretion. This work was set to investigate the effects of the presence of hydrocortisone in zinc oxide eugenol sealers (Endomethasone N) on modulating the initial steps of inflammation in vitro. MATERIAL AND METHODS: Hydrocortisone and eugenol leaching from Endomethasone N and Pulp Canal Sealer (PCS) were quantified by ELISA and spectrofluorometry, respectively. The effects of Endomethasone N and Pulp Canal Sealer were studied on lipopolysaccharides (LPS)-stimulated human periodontal ligament (hPDL) cells. Cytokine (IL-6, TNF-α) secretion from cells was quantified by ELISA. Inflammatory cell (THP-1) adhesion to activated endothelial cells, their migration and activation were studied in vitro. RESULTS: Endomethasone N decreased secretion of IL-6 and TNF-α from hPDL cells. THP-1 adhesion to activated endothelial cells (HUVECs) and migration significantly decreased with Endomethasone N while no effect was observed with PCS. Activation of THP-1 decreased with both materials' extracts but was significantly lower with Endomethasone N than with PCS. CONCLUSION: These results performed in vitro show that Endomethasone N anti-inflammatory effects are due to the presence of hydrocortisone. CLINICAL RELEVANCE: Endomethasone N has potential local anti-inflammatory effects which appear to be due to its hydrocortisone rather than eugenol content. Decreasing the inflammatory response is a pre-requisite to initiate the periapical healing.

Root canal obturation materials and filling techniques for primary teeth: In vitro evaluation in polymer-based prototyped incisors.

BACKGROUND: Achieving a void-free root canal filling is a challenge in current clinical pulpectomy practice. AIM: To compare filling effectiveness and internal voids of root filling materials and obturation techniques in resin-prototyped primary incisors by micro-CT. DESIGN: Fifty prototypes were instrumented and randomly divided (n = 10) according to the filling materials (Vitapex® , ZOE, Calcicur® , Feapex, and Calen® -ZO) and obturation technique: lentulo or pressure syringe (n = 5). The specimens were micro-CT scanned (pixel size = 7.83 µm) and reconstructed, and the total volume of filled canal (%FC) and internal voids (%IV) of the bulk filling material was calculated. Kruskal-Wallis and Mann-Whitney tests were used to detect differences and interactions among groups. RESULTS: Calen® -ZO, Vitapex® , and ZOE showed similar %FC. Calcicur® showed lower %FC compared with Calen® -ZO, Vitapex® , and ZOE (P < .05) but similar to Feapex. No statistically significant differences in %FC between lentulo or pressure syringe were disclosed. Regarding %IV, Vitapex® , and Calen® -ZO performed better with syringe, although Calcicur® was better with lentulo. The number of voids in the obturation bulk was similar among materials, but always lower (P < .05) in syringe filled specimens. CONCLUSION: Vitapex® , Calen® -ZO, and ZOE outperformed Calcicur® and Feapex in %FC and if the syringe technique is used, %IV of the obturation bulk and presence of defects was lower.

Low-cost modified-atmosphere hermetic storage structures to reduce storage losses of maize (Zea mays L.) cobs and sorghum (Sorghum bicolor L.) heads.

BACKGROUND: Production and marketing of cereal grains are some of the main activities in developing countries to ensure food security. However, the food gap is complicated further by high postharvest loss of grains during storage. This study aimed to compare low-cost modified-atmosphere hermetic storage structures with traditional practice to minimize quantitative and qualitative losses of grains during storage. The study was conducted in two phases: in the first phase, seven hermetic storage structures with or without smoke infusion were compared, and one selected structure was further validated at scaled-up capacity in the second phase. RESULTS: Grains stored in PVC bag-supported structures (with or without smoke infusion) resulted in low live weevil population, low percentage of damaged grains and reduced weight loss with better retention of crude protein and fat contents. Results from validation study also demonstrated that maize and sorghum stored in improved storage structures experienced, respectively, 9.8% and 10.4% weevil damage as compared with 47.3% and 42.3% when stored in traditional storage structures. The same was true in terms of crude protein and fat contents. CONCLUSIONS: The study demonstrated that storage structures supported with PVC bags are efficient and low-cost structures for reducing storage-related losses and supporting food security efforts as compared to traditional methods. Furthermore, the bags can be made locally and with various storage capacities to store either shelled or unshelled products. © 2019 Society of Chemical Industry.

The effect of smear layer on bacterial penetration through roots obturated using zinc oxide eugenol-based sealer.

BACKGROUND: Smear layer removal has been shown to reduce bacterial penetration through root canal obturations when resin-based endodontic sealer is used. The purpose of this in vitro study was to test this effect when a non-resin-based sealer is used. MATERIAL AND METHODS: Thirty root segments were assigned to the following groups: Smear layer removed (n = 8); smear layer retained (n = 8); negative controls (n = 10; 5 with smear layer, 5 without); and positive controls (n = 4; 2 with smear layer, 2 without). After rotary instrumentation, smear layers were removed in the treatment group and half of controls using 17% ethylenediamenetetraacetic acid (EDTA) prior to obturation. Each obturated root was affixed into a dual-chamber leakage model employing Streptococcus mutans. Roots were incubated at 37 °C for 120 d. Days until lower chamber turbidity occurred was recorded for each sample, and data were analyzed using Kaplan-Meier survival curve analysis (p = 0.05). RESULTS: No negative controls leaked, while all positive controls were turbid within 1 day. Mean days to leakage for roots with smear layer intact was 82.75 (+/- 33.29, 95% CI), although three never leaked. Mean days to leakage through roots with smear layer removed was 46.25 (+/- 26.67, 95% CI), and all leaked. Treatment survival curves were significantly different (p = 0.048). CONCLUSIONS: Under the conditions and limitations of this study, retaining the smear layer reduced the rate of bacterial penetration through canals which had been obturated using zinc oxide eugenol (ZOE) -based sealer.

The effect of nonthermal plasma on the push-out bond strength of two different root canal sealers.

BACKGROUND: An optimum bonding between the sealer and dentin is important for impermeable root canal filling and many procedures were applied to improve root canal dentin and in turn the bond strength between the sealer and dentine. There is lack of sufficient data on the effect of nonthermal plasma application on the bond strength of sealers to the root canal dentin. AIM: The purpose of this study was to evaluate the effect of NAP on the push-out bond strength (PBS) of a bioceramic and resin-based root canal sealer (RCS) to root canal dentin. MATERIALS AND METHODS: Forty single-rooted mandibular premolars were decoronated. After preparation and final irrigation, the specimens were divided into four groups (n = 10). Group AH: Root canals were filled with gutta-percha (GP) and AH Plus RCS, Group P-AH: Root canals were filled with GP and AH Plus RCS following the NAP application, Group BC: Root canals were filled with GP and Endosequence BC RCS, and Group P-BC: Root canals were filled with GP and Endosequence BC RCS following the NAP application. Then roots were sectioned horizontally to obtain ~1 mm thick dentin disks. PBS test was performed to the second (coronal) and fourth (middle) slices. Data were analyzed with the Kruskal-Wallis and t-test. RESULTS: There was a statistically significant difference among the groups for both coronal and middle regions (P < 0.05). P-BC group showed higher PBS than AH and P-AH groups in the coronal region. P-BC group showed higher PBS than the other groups in the middle region. CONCLUSIONS: The use of NAP did not influence the push-out bond strength of AH-Plus sealer to the root canal dentin. The Endosequence-BC sealer showed a better bond strength than the AH-Plus sealer after NAP application.