Three-Dimensional Measurement of Obturation Quality of Bioceramic Materials in Filling Artificial Internal Root Resorption Cavities Using Different Obturation Techniques: An In Vitro Comparative Study.

INTRODUCTION: Pathologic conditions such as internal root resorption (IRR) may complicate root canal filling. This study aimed to evaluate and compare the obturation quality by measuring the percentage of obturation volume (POV) in root canals with artificial IRR obturated with different materials and techniques using cone beam computed tomography (CBCT). METHODS: Forty single canal extracted mandibular premolars were decoronated to standardize their length to 14 mm. Following instrumentation, the roots were cut horizontally, and artificial IRR cavities were made at the level of 7 mm from the apex. The root halves were joined using cyanoacrylate adhesive. The samples were randomly assigned to 4 groups (n = 10), and the canals were filled as follows: single-cone technique (SC), bulk-fill Bio-C Sealer (BF), and Bio-C Repair for the coronal and middle third (BCR) + cold lateral condensation technique (CLC) for the apical third and continuous wave compaction technique (CWC). The pre- and postobturation volumes and the POV were measured in the total canal and for the apical, middle, and coronal thirds separately using CBCT and Mimics Medical software. The results were analyzed statistically using one-way ANOVA and Tukey HSD test, and statistical significance was set at P < .05. RESULTS: BF group resulted in significantly lower total, coronal, middle and apical POV values compared to SC, BCR + CLC, and CWC groups (P < .05), respectively. Also, at the apical third, the BCR + CLC group showed significantly lower POV than the SC and CWC groups (P < .05), respectively. The intra-group comparison showed that BF and BCR + CLC groups had a significantly lower POV in the apical third compared to the middle third (P < .05). Conversely, the CWC group had a significantly higher apical POV than the middle third (P < .05). CONCLUSIONS: The maximum POV was obtained using the CWC technique, Bio-C Repair, and SC technique with Bio-C Sealer, making their application in IRR more preferable than the BF Bio-C Sealer.

Assessment of Bacterial Load and Post-Endodontic Pain after One-Visit Root Canal Treatment Using Two Types of Endodontic Access Openings: A Randomized Controlled Clinical Trial.

The need for controlling bacteria and pain during root canal therapy is undeniable. This clinical trial aimed to assess whether there is a difference in colony-forming unit (CFU) reduction after instrumentation and post-endodontic pain after root canal treatment (RCT) using a traditional endodontic cavity (TEC) versus a conservative endodontic cavity (CEC). This clinical study was conducted on 89 patients designated for a single-visit RCT. Patients were allocated randomly (TEC n = 45 and CEC n = 44). The access opening was gained accordingly in each group by a single operator. A pre-instrumentation sample of root canal dentin was collected using an endodontic file; the second sample was collected similarly, right after shaping and cleaning the root canal. The CFU was calculated based on the samples collected. The pain level was recorded preoperatively and at 1, 7, and 21 days postoperatively utilizing a visual analog scale (VAS). There were no statistically significant differences in the CFU reduction between the TEC and CEC groups (p > 0.05). Additionally, there were no statistically significant differences found in postoperative pain levels between the TEC and CEC at 1, 7, and 21 days (p > 0.05). Despite the limitations of this study, both the CEC and TEC demonstrate a decrease in bacteria within the root canals and alleviate postoperative pain with no difference between them.

Comparison between the theoretical and experimental values of transition rate B(E2), deformation parameters and intrinsic quadrupole moments for some Ti isotopes.

In this study, electric quadrupole transition properties in some even-even Ti nuclei have been investigated by using different effective charges and interactions. In this respect, B(E2) transition rates, deformation parameters and intrinsic quadrupole moments have been calculated. In calculations, NuShellX code has been used to calculated one body matrix elements (OBDM). Theoretical calculations on these quantities have been compared with the experimental results, and it has been seen that theoretical values obtained by using the kb3 and vpnp interactions and Bohr Mottelson (B-M) and Standard (S-T) effective charges are close to the corresponding experimental results.

Prevalence of periapical lesions in non-endodontically and endodontically treated teeth in an urban Iraqi adult subpopulation: A retrospective CBCT analysis.

Background: This study aimed to assess the prevalence of apical periodontitis (AP) and its association with the presence/quality of root canal filling (RCF) and coronal restoration (CR) in Iraqi population. Material and Methods: A total of 385 CBCT scans of patients (18-45) yrs. old with 9250 teeth were examined. The teeth were grouped according to the presence/absence of apical radiolucency, presence/radiographic quality of RCF, and CR. Chi-square and Kappa were used to assess associations and intra-consensus reliability. Logistic regression was used to predict risk factors associated with AP. The significant level was set at p<0.05. Results: AP was prevalent in 17.7 and 80.2% of teeth without RCT and with RCT (p<0.05), respectively. AP in root canal-treated teeth with missed canals (93.2%) was higher than that in root canal-treated teeth with no missing canal (78.3%) (p<0.05). AP in teeth with inadequate RCF (87%) was higher than that in teeth with adequate RCF (63%) (P<0.05). No difference in the prevalence of AP in teeth with adequate vs inadequate CR ((79.7%) vs (81%), respectively) (p>0.05). The presence of AP was significantly associated with inadequate RCF (vs adequate RCF) (OR=4.16, CI 95% 2.29-7.56, P<0.05), and was not associated with inadequate CR (vs adequate CR) (OR=-0.71, CI 95% 0.35-1.42, P>0.05). Intra-consensus reliability was (0.9) for AP and (0.82) for RCF and CR quality. Conclusions: AP was highly prevalent in teeth with previous root canal filling compared to non-treated teeth. AP was significantly associated with inadequacy of root canal filling but not with the inadequacy of coronal restoration. Key words:Apical periodontitis, cone beam computed tomography, root canal treatment, endodontics.

Cusp deflection and fracture strength of root canal filled premolars with two access cavities designs (Conservative vs Traditional).

Background: This study evaluated two endodontic access designs (Conservative (Cons) vs Traditional (Trad)) of class I and class II cavities on cusp deflection (CD) and fracture strength (FS) of root canal filled maxillary premolars. Material and Methods: Seventy-two sound maxillary first premolars were included in this study; Teeth were randomly assigned into nine groups (n=8), a positive control group where teeth left sound and the other eight according to the access cavity designs (Cons class I, Trad class I, Cons class II and Trad class II). After access preparation, teeth were endodontically-treated. Four groups were restored with FiltekTM Bulk-Fill composite. While the other four groups were left without coronal restoration as negative controls for fracture strength. Following thermocycling (500 cycles), CD values were recorded for the restored teeth at the following intervals, after cavity preparation, 15 min after restoration and after thermocycling. The samples were then subjected to fracture using a universal testing machine. The data were analyzed using one-way ANOVA and Tukey Post-Hoc. Statistical significance was set at p<0.05. Results: There was a significant difference between groups at 15 min after restoration (p<0.000) and there were no differences after cavity preparation and after thermocycling (p>0.05). At 15 min after restoration, the CD value was significantly higher in Trad class II than in other types of cavities (p<0.05) and there was no difference between Cons and Trad class I (p>0.05). In each group, the CD value was significantly higher 15 min after restoration compared to that after cavity preparation and after thermocycling in all groups. The highest FS was recorded for the control group (1240 N), while the lowest was for the Trad class II not restored group (472.8 N). One-way ANOVA test showed a highly significant difference between groups (p<0.000) and there were no significant differences in FS between the Cons vs Trad access cavity designs in class I and class II cavities, respectively. Conclusions: Cusp deflection increased by the increase in the size of cavity preparation and stress relaxation tends to occur after thermocycling. Moreover, the conservation of the endodontic access cavity could improve the resistance of the tooth to fracture compared to its traditional counterpart but not to a statistically significant point. Key words:Conservative, traditional, endodontic access cavity, cusp deflection, fracture strength.

High-Endurance Magneto-Electronic Switchable Molecular Electronic Crystal.

Electrically switchable magnetic and electronic properties are promising for quantum sensing and information technology. Here, we report an electrically driven magnetic and electronic phase transition in molecular electronic crystal, potassium-7,7,8,8-tetracyanoquinodimethan, with the magneto-electric switching over 105 cycles at room temperature. Electron spin resonance study reveals the cooperative transition between spin and charge degrees of freedom. In addition, the mechanistic spectroscopy studies suggest the charges in an inhomogeneous conductor-insulator mixed state. The findings shown here suggest electrically controlled ordering in strongly correlated molecular crystal leads to dynamic magneto-electric switching, paving the way for developing molecular-based memory and switching devices.

Laser-Induced Cooperative Transition in Molecular Electronic Crystal.

The competing and non-equilibrium phase transitions, involving dynamic tunability of cooperative electronic and magnetic states in strongly correlated materials, show great promise in quantum sensing and information technology. To date, the stabilization of transient states is still in the preliminary stage, particularly with respect to molecular electronic solids. Here, a dynamic and cooperative phase in potassium-7,7,8,8-tetracyanoquinodimethane (K-TCNQ) with the control of pulsed electromagnetic excitation is demonstrated. Simultaneous dynamic and coherent lattice perturbation with 8 ns pulsed laser (532 nm, 15 MW cm-2 , 10 Hz) in such a molecular electronic crystal initiates a stable long-lived (over 400 days) conducting paramagnetic state (≈42 Ωcm), showing the charge-spin bistability over a broad temperature range from 2 to 360 K. Comprehensive noise spectroscopy, in situ high-pressure measurements, electron spin resonance (ESR), theoretical model, and scanning tunneling microscopy/spectroscopy (STM/STS) studies provide further evidence that such a transition is cooperative, requiring a dedicated charge-spin-lattice decoupling to activate and subsequently stabilize nonequilibrium phase. The cooperativity triggered by ultrahigh-strain-rate (above 106 s- 1 ) pulsed excitation offers a collective control toward the generation and stabilization of strongly correlated electronic and magnetic orders in molecular electronic solids and offers unique electro-magnetic phases with technological promises.

Structural and functional relations between the connective tissue and epithelium of enamel organ and their role during enamel maturation.

The morphological and possible functional interactions between the connective tissue and enamel organ cells were examined during the maturation phase of enamel formation, using immunohistochemical techniques. Decalcified mandibular sections (10 µm) including incisors were used from Wistar rats ages 10-12 weeks. Sections were incubated with one or two primary antibodies targeting cell cytoskeleton (vimentin, α-actin, α-tubulin), dendritic marker (OX6), gap junctions (cx-43), enzymes (nitric-oxide synthase (nos1) and cyclooxygenase (cox1)), and the ion transporters (Na+/H+ exchanger (NHE1) and Na+/Ca2+ exchanger (NCX)) for 24 h, before incubation with the appropriate conjugated fluorescent secondary antibodies. Sections were examined by fluorescence microscopy. Haematoxylin-eosin slides were also employed. Cellular heterogeneity and morphological modulations were identified within enamel organ cells and connective tissue covering suggesting complex cellular interactions and indicating a new functional concept and possible complementary role during enamel maturation. Also, some ion transportation activity, and nos1 and cox1 signalling pathways have been identified, indicating intercellular communication between these regions. A hypothesis is suggested, to explain the morphological modulation of ameloblasts and papillary cells during enamel maturation which functions to increase the transporting membrane surface area to accomplish faster and bulker ion transportation to achieve controlled pH and to direct Ca2+ towards enamel.

Self-Limiting versus Rotary Subjective Carious Tissue Removal: A Randomized Controlled Clinical Trial-2-Year Results.

BACKGROUND: the aim of this study was to assess the 2-year pulp survival of deep carious lesions in teeth excavated using a self-limiting protocol in a single-blind randomized controlled clinical trial. METHODS: At baseline, 101 teeth with deep carious lesions in 86 patients were excavated randomly using self-limiting or control protocols. Standardized clinical examination and periapical radiographs of teeth were performed after 1- and 2-year follow-ups (REC 14/LO/0880). RESULTS: During the 2-year period of the study, 24 teeth failed (16 and 8 at T12 and T24, respectively). Final analysis shows that 39/63 (61.9%) of teeth were deemed successful (16/33 (48.4%) and 23/30 (76.6%) in the control and experimental groups, respectively with a statistically significant difference (z score = 2.3, p = 0.021). Of teeth with severe and mild symptoms at T0, 42.9% and 36.7% respectively failed at T24 (p > 0.05). Within the self-limiting group, there was a lower success in premolars compared to molars (p < 0.05). CONCLUSION: after 2 years, there was a statistically significant higher pulp survival rate of teeth with deep carious lesions excavated using self-limiting protocols in patients with reversible pulpitis. Molars showed higher success than premolars in teeth excavated using the self-limiting protocol. There was no statistically significant association between the outcome and the severity of symptoms at T0 (ClinicalTrials.gov NCT03071588).

Bond strength of a new Kevlar fiber-reinforced composite post with semi-interpenetrating polymer network (IPN) matrix.

BACKGROUND: This study aimed to evaluate the bond strength and the penetration depth of two adhesive systems to a new experimental semi-IPN fiber post versus a commercial post. MATERIAL AND METHODS: Experimental Kevlar fiber (KF) and control everStick®POST (ES) posts (n=20/ group) with a diameter of 1.5 mm were used, 10 posts coated with StickResin (SR) and the other 10 posts coated with Scotch bond multipurpose (SBMP) adhesives. Composite resin buildup was performed over each post, using a cylindrical plastic mold (10 mm × 6 mm). Four discs of 2 mm thickness were prepared from each post/composite buildup and underwent pushout bond strength test at a crosshead speed of 0.5 mm/min accompanied by failure mode analysis. A further three specimens from each subgroup were bonded with adhesives labeled with 0.1 wt% Rhodamine B and embedded in acrylic resin, sectioned and examined under a confocal Laser-scanning microscope (CLSM) to measure the depth of resin penetration. Statistical analysis included ANOVA and Tukey test, the significance level was assumed at a p-value less than 0.05. RESULTS: The push-out bond strength of KF was comparable to that of ES with both SBMP and SR adhesives (P >0.05). Bond strength value for SBMP was higher than SR adhesive in either ES and KF posts with no significant difference (P > 0.05). ES exhibited higher adhesive penetration depth compared with KF (p<0.05). CONCLUSIONS: The bond strength of Kevlar post was comparable with the everStick post and the semi-interpenetrating structure of Kevlar post displayed some adhesive monomers diffusion indicating its usefulness as a new intracanal post. Key words:Kevlar fiber post, Bond strength, Penetration depth, Confocal, Semi-IPN polymer system.

One stage reconstruction of the floor of the mouth with a subcutaneous pedicled nasolabial flap.

BACKGROUND: Nasolabial flaps have been recognised as versatile flaps for a variety of defects in the face, nose, lip and the oral cavity. Random pattern inferiorly based nasolabial flaps (NLF) have been utilised for covering small defects on the anterior floor of the mouth, but usually require a second stage procedure to divide the flap base. A subcutaneous pedicled inferiorly based nasolabial flap can provide a one stage repair of moderate sized defects of the floor of the mouth after de epithelialisation of the base of the flap. AIM: To evaluate the feasibility of a single stage reconstruction of intermediate sized defects in the oral cavity with an inferiorly based pedicled NLF. The study includes the indications of use of the flap, flap design, technique, and the complications rate. The incidence of secondary procedures and the final functional and the aesthetic results will also be evaluated. MATERIALS AND METHODS: A group of 20 patients presented with (T1-2) squamous cell carcinoma of the oral cavity have been treated at the Department of Surgery, National Cancer Institute, Cairo; in the period between January 2008 and September 2010. The pathology was confirmed with an incision biopsy and all metastatic work were carried out confirming that all patients were free from distant metastasis at presentation. Preoperative assessment also included assessment of the stage of the disease, the flap design and patient fitness for general anaesthesia. All patients underwent surgical excision combined with reconstruction of the defect with a subcutaneous inferiorly based pedicled NLF. The proximal part of the flap was routinely de epithelialised before it has been tunnelled through the cheek so a one stage procedure could only be required. RESULTS: The mean age of the patients was 62.3±6years, range (52-69years). All patients were diagnosed with squamous cell carcinoma. The anterior floor of the mouth constituted 40% of the defects, the lateral floor of the mouth 20% and the inner surface of the cheek 40%. There was no reported major complication; and only one patient suffered a reactionary haemorrhage that required re-exploration to secure the bleeder. A single procedure was adequate in most patients (80%), only 20% of patients required revision of the scar at the donor site or release of the tongue. The overall aesthetic results were either very satisfactory or satisfactory in the majority of patients (90%). Two patients were not satisfied with the final aesthetic results, one suffered from ectropion and the other had a donor site wound healing problem. The functional results (deglutition, speech) were satisfactory in most patients (70%), all were edentulous. CONCLUSION: An inferiorly based pedicled NLF is a reliable flap for the reconstruction of small and medium sized defects in the oral cavity. The flap can be best utilised for old edentulous and high risk patients where it can be used as a single stage procedure which is particularly useful in those types of patients. The flap can be safely combined with neck dissection even when the facial artery was ligated.

Diagnosis and management of small bowel and mesentery injury following blunt abdominal trauma in 12 cases.

Over four years (April 2004 to December 2008) 12 patients with blunt small bowel and mesenteric injuries were treated at three hospi-tals dealing with trauma. Ten cases were victims of traffic accidents, of whom 70% wore seat belts. There were 11 small bowel injuries (4 full-thickness & 7 seromuscular) and 9 mesenteric injuries (3 with & 6 without a de-vascularized bowel segment). All were managed initially following the Advanced Trauma Life Support (ATLS) guidelines. Emergency room ultrasound was positive for blood in 5/7 cases (71%) and CT scan in 2/4 (50%). Diagnostic peritoneal lavage (DPL) was performed in one case and was positive for blood.