CLINICAL AID A New Approach for the Retrieval of Broken Instruments

The purpose of this article is to present a modified ultrasonic spreader and a new technique that are used for the retrieval of solid obstructions that can not be bypassed by conventional methods. The technique advocated and the instruments proposed are described. A clinical case is discussed to show the possibilities and limitations of both instrument and method. Several methods and techniques are advocated for the removal of solid objects, such as silver points, fragments of an instrument, or posts. Accessible solid obstructions may be withdrawn from the canal by a variety of instruments, including forceps, pliers, or a Castroveijos needle holder (1-3). Sometimes mechanical interventions should be undertaken and sophisticated tools such as the Masserann endodontic kit (4) and the Endo Extractor (5) are recommended. Endodontic textbooks (6) advocate bypassing the obstruction before trying to retrieve it from the canal. It could be done manually by the use of one or multiple Hedstrom files MATERIALS AND METHODS Instrumentation consists of a piezoelectric ultrasonic unit and an ultrasonic spreader (S04) by Satellec (France). The modifications suggested to the spreader concerns its taper and diameter. A separating disc (Speedy, Hollicer, France) is used to reduce the diameter at the tip to 0.20 to 0.25 mm at D1 and at D2 (16 mm from D1) to 0.5 to 0.6 ram. This will roughly make a taper 0.02 spreader. A small round bur (#2 of Maillefer, Ballaigues, Switzerland) is used to make a hole in the shank to allow irrigation 633 sectional diameter to obtain a predictable caliber (GG1 = 0.5 mm, GG2 = 70 mm) (12). A #10 file and 25 mm long shortened by (2 to 3 mm) will have a sharp edge at the working end and a suitable rigidity (13). This technique is applied whenever bypassing the obstruction is impossible. It could be divided into three steps. Step l: The clinician should create sufficient space coronal to the obstruction. This is accomplished by serial use of files and GG drills. Files ar

The Influence of Brushing Motion on the Cutting Behavior of 3 Reciprocating Files in Oval-shaped Canals

International audienceIntroduction: The purpose of this study was to compare the cutting efficiency of 3 reciprocating single-file systems used with a brushing motion in oval-shaped canals. Methods: Sixty premolars with single oval canals were selected and randomly assigned to 3 groups according to the file used in canal instrumentation: R25 Reciproc (VDW, Munich, Germany), Primary WaveOne ((Dentsply Maillefer, Ballaigues, Switzerland), and a novel prototype instrument (UFile; MicoMega, Besancon, France). Instru-mentation was performed in 4 consecutive steps; according to manufacturers' instructions, 5 brushing strokes against the buccal wall with a nonworking instrument followed by another 5 and 15 brushing strokes with a working file. Cone-beam computed tomographic scans were taken after each step of preparation. Pre-and postinstru-mentation images were superimposed at the apical and midroot levels and then evaluated in terms of changes in the maximum buccolingual (DBL) and mesiodistal dimensions (DMD). Results: Instrumentation with a brushing motion resulted in the following findings. At the apical levels, no significant difference was found in DBL for the 3 groups (P > .05). However, DMD was significantly less for the Reciproc (P = .006) and UFile (P = .03) groups. At the midroot levels, the UFile group showed the highest significance in terms of DBL (P < .0001) but the lowest in terms of DMD (P = .003). DMD was significantly the highest for the WaveOne group at the midroot levels (P = .05). Conclusions: The prototype file was more efficient than the other files at the midroot levels, whereas all systems acted the same at the apical levels. The increase in the number of brushing strokes resulted in more dentinal cutting in the direction of those strokes. (J Endod 2015;-:1–7

Land use impacts of implementing a bus rapid transit system: case of Beirut southern corridor

Abstract This study investigates and forecasts the effects of implementing a newly proposed Bus Rapid Transit (BRT) system in Lebanon on the urban land use evolution between the years 2019 and 2049. It contributes to the emerging scientific literature by proposing a technique intended to identify the potential urban land use impacts of BRT. The identification of these impacts as part of the feasibility study for the BRT is considered important for policymakers, local officials, and urban planners. The impacts are identified by conducting the Analytical Hierarchy Process, based on data collected via survey and interviews with real estate experts. The outcomes show that implementing a BRT service complemented with bus feeder services will: (i) reshape the urban fabric, in proximity to BRT routes and particularly around the stations, by triggering the Transit-Oriented Development and increasing the attractivity of urban development by 6 to 9% according to the distance from BRT route; and (ii) increase the attractivity of urban development projects by 11% in areas distant from the highway if these areas are characterized by high coverage of bus feeder services, low possibility of an increase in estate prices, and medium to high public acceptance of the proposed BRT

Impacts of a New Highway on Urban Development and Land Accessibility in Developing Countries: Case of Beirut Southern Entrance in Lebanon

International audienc

Artificial Intelligence in Endodontics

ABSTRACTBackground In recent years, with advancements in science and technology, artificial intelligence (AI) has been gaining more relevance in the field of dentistry in general, as well as endodontics. AI-guided algorithms have a great potential to better diagnose, treatment plan, and execute endodontic treatments, as well as outcome prediction of the various endodontic treatments. A review of literature was conducted to assess the application of AI in the field of endodontics.Results AI has been used in a variety of clinical applications including the assessment of root canal anatomy, working length, presence of root fractures, and outcome prediction.Conclusion Within the field of endodontics, AI has already been proven to be useful. The evolution of this technology and its continuous application can positively impact the field of endodontics and assist in preserving the natural dentition. Clinical implications: AI is currently being used for specific endodontic applications and possible potential applications in the future horizon

Passengers receptivity of a new public transport mode: case of a BRT project in Lebanon

International audienceAbstract This study examines how far the level of knowledge on a new public transport mode in Lebanon might affect mode choice. Indeed, passenger mode choice is a major issue associated with the effectiveness of new transport projects, as their level of effectiveness and feasibility will depend on the number of new adopters. This investigation is performed by developing mode choice models based on data collected via a questionnaire-based survey. The models were used to compare preferences among private cars, current public transport modes and a newly proposed Bus Rapid Transit system. The driving factors are divided into two categories: economic and psychological. The results reveal that explicit evaluations of several factors on the proposed transport modes yields mode choices different from direct evaluation. Besides, the structure of the utility function reveals that economic driving factors prevail over the psychological aspects, which is the opposite of what is observed with direct mode assessment. Moreover, people’s expectations of the proposed Bus Rapid Transit were significantly positive in terms of usability in addition to operational and economic reliability. This study shows that people’s level of knowledge of previous transport modes and their perceptual expectations of new travel modes must be taken into consideration in the feasibility studies of any transport implementations in the developing countries where the public transport services are discouraged

Influence of Coronal Flaring on the Shaping Ability of Two Heat-Treated Nickel-Titanium Endodontic Files: A Micro-Computed Tomographic Study

Nickel-titanium (NiTi) usage is associated in endodontics with some complications including canal transportation. Centering ability of a NiTi file is the ability to stay centered in the root canal system during instrumentation. Any undesirable deviation from the natural canal path is indicated as canal transportation. A possible strategy to improve the centering ability of NiTi instruments is the pre-enlargement of the coronal third of the root canal to minimize coronal interferences. This procedure is known as coronal flaring. The aim of this study was to perform a micro-computed tomographic (micro-CT) evaluation of the effect of coronal flaring on canal transportation and centering ability of two heat treated nickel-titanium rotary instruments, 2Shape (Micro Mega, Besançon, France) and HyFlex CM (Coltène Whaledent, Altstätten, Switzerland). Thirty extracted mandibular molars with two independent mesial canals were selected and randomly instrumented (n = 15 canals) with One Flare (Micro Mega, Besançon, France) before HyFlex CM, HyFlex CM (without coronal flaring), One Flare before 2Shape and 2Shape (without coronal flaring). One Flare (Micro Mega, Besançon, France) was introduced 4 mm below the canal entrance for canals prepared with coronal flaring. HyFlex CM and 2Shape were used accordingly to manufacturers’ instructions. New files were used for each canal. During and after instrumentation, irrigation procedures were performed. Micro-CT images were obtained pre- and post-preparation to measure and record root canal transportation and centralization. They were reconstructed from root apex to canal orifices, generating approximately 1000 sections per specimen. The anatomical thirds were determined by dividing the number of cross-sectional slices by three. Root canal transportation and centralization were determined by Gambil method, and the mean values were analyzed by repeated measures analysis of variance followed by multiple comparisons of Bonferroni to compare the different instrumentations procedures and the root thirds (p < 0.05). As for root canal transportation, 2Shape reported significantly higher values compared to HyFlex CM in the cervical region independently from the coronal flaring. In the apical region, 2Shape caused significantly minor canal transportation when used with coronal flaring with compared with the absence of coronal flaring. Regarding the centralization, HyFlex CM showed higher values than 2Shape in the cervical, independently from coronal flaring. In the apical region, 2Shape with coronal flaring exhibited significant major centering ratio, compared with not. Within the limitations of this study, coronal flaring reduced canal transportation and improved centralization of the 2Shape files in the apical section while it had no significant influence on shaping ability of the HyFlex CM instruments. Coronal flaring could represent a valid strategy to improve the shaping ability of NiTi files knowing that its benefit could be influenced by the shaping file used

Physicochemical and Antibacterial Properties of Conventional and Two Premixed Root Canal Filling Materials in Primary Teeth

International audienceIn this study, some physicochemical and antibacterial properties of three root canal filling materials for primary teeth, Calplus "CP" (Prevest DenPro, Lewes, DE, USA), Bio-C Pulpecto "Bio-CP" (Angelus, Basil, Londrina, Paraná, Brazil), and Zinc Oxide and Eugenol "ZOE" (Prevest DenPro, Lewes, DE, USA) were compared. For each material, the pH, solubility, contact angle, and crystalline microstructure under SEM were evaluated. Their antibacterial activity against Enterococcus faecalis was determined through direct tests. The Kruskal-Wallis test was used to analyze the results using a one-way analysis of variance on ranks. All the materials had an alkaline pH at 3, 24, and 72 h, with CalPlus having the highest (p < 0.05). Bio-CP was more soluble during the evaluation period (24 h) than ZOE and CalPlus (p < 0.05). Bio-CP and ZOE demonstrated the creation of crystallite structures on their surfaces after immersion in PBS at 37 • C, whereas CalPlus showed none. The lowest contact angle was observed for Bio-CP (53 ± 1.5 •); contact angles of (86 ± 4 •) and (96 ± 1 •), respectively, were observed after 10 s of the deposition of the water drop for CalPlus and ZOE. In conclusion, according to this study, there is still a need to develop new filling materials for primary teeth. ZOE, CalPlus and Bio-CP demonstrated different physicochemical and antibacterial properties, but none of the materials had optimal properties and could be considered the most suitable filling material for primary teeth pulpectomy. Bioceramics in their current state are not an alternative. The physicochemical and antibacterial properties still need improvement to fit the intricate anatomy of primary teeth

Influence of NiTi Wire Diameter on Cyclic and Torsional Fatigue Resistance of Different Heat-Treated Endodontic Instruments

We compared the mechanical properties of 2Shape mini TS2 (Micro-Mega, Besançon, France) obtained from 1.0 diameter nickel-titanium (NiTi) wires and 2Shape TS2 from 1.2 diameter nickel-titanium (NiTi) wires differently thermally treated at room and body temperature. We used 120 NiTi TS2 1.0 and TS2 1.2 files made from controlled memory (CM) wire and T-wire (n = 10). Cyclic fatigue resistance was tested by recording the number of cycles to fracture (NCF) at room and body temperatures using a customized testing device. Maximum torque and angle of rotation at failure were recorded, according to ISO 3630-1. Data were analyzed by a two-way ANOVA (p < 0.05). The CM-wire files had significantly higher NCFs at both temperatures, independent of wire dimensions. Testing at body temperature negatively affected cyclic fatigue of all files. The 1.0-mm diameter T-wire instruments showed higher NCF than the 1.2-mm diameter, whereas no significant differences emerged between the two CM wires at either temperature. The maximum torque was not significantly different across files. The TS2 CM-wire files showed significantly higher angular rotation to fracture than T-wire files. The TS2 CM-wire prototypes showed higher cyclic fatigue resistance than T-wire prototypes, regardless of wire size, exhibiting suitable torsional properties. Torsional behavior appears to not be affected by NiTi wire size

Evaluation of Two Shaping Systems and Two Ultrasonic Irrigation Devices in Removing Root Canal Filling Material from Mesial Roots of Mandibular Molars: A Micro CT Study

We assessed the efficiency of two shaping file systems and two passive ultrasonic irrigation (PUI) devices for removing filling material during retreatment. The mesial canals from 44 extracted mandibular molars were prepared and obturated. The teeth were randomly divided into two groups, and then one group was retreated with Reciproc R25 (VDW, Munich, Germany) (n = 44) and the other group was retreated with 2Shape (TS, Micro Mega, Besan&ccedil;on, France) (n = 44). A micro-computed tomography (CT) scan was taken before and after the retreatment to assess the volume of the filling material remnants. The teeth were then randomly divided into four groups to test two different PUI devices: Irrisafe (Satelec Acteon Group, Merignac, France) and Endo Ultra (Vista Dental Products, Racine, WI, USA). The teeth in Group A were retreated with 2Shape to test the Endo Ultra (n = 22) device, the teeth in Group B were retreated with 2Shape in order to test the Irrisafe (n = 22) device, the teeth in Group C were retreated with Reciproc to test the Endo Ultra (n = 22) device, and Group D was retreated with Reciproc to test the Irrisafe (n = 22) device. A third micro-CT scan was taken after the retreatment to test the PUIs. The percentage of Gutta-Percha (GP) and sealer removed was 94.75% for TS2 (p &lt; 0.001) and 89.3% for R25 (p &lt; 0.001). The PUI significantly enhanced the removal of the filling material by 0.76% for Group A (p &lt; 0.001), 1.47% for Group B (p &lt; 0.001), 2.61% for Group C (p &lt; 0.001), and by 1.66% for Group D (p &lt; 0.001). 2Shape was more effective at removing the GP and sealer during retreatment (p = 0.018). The supplementary approach with PUI significantly improved filling material removal, with no statistical difference between the four groups (p = 0.106)