Jig Method Research Articles

Plywood Jig—A New Technique for Root Canal Curvature Measurement

The successful outcome of endodontic treatment is dependent on complete cleaning, shaping as well as three dimensional obturation of the root canal system. A conventional radiograph is a two-dimensional replication of a three-dimensional object and does not provide any conclusive evidence for canal curvatures. An accurate knowledge of the tooth anatomy and curvature is essential to avoid procedural errors. 100 freshly extracted human teeth were used in this study. Digital images were obtained using the plywood JIG and Schneider’s technique. These images were analyzed using the VixWin Pro digital image analyzing software (Gendex system). Statistical analysis was done using paired t test. The canal curvature average values measured using Jig method and Schneider method for mandibular teeth are 28.23° (±9.96) and 22.07° (±9.46) respectively. The smallest/largest curvature angles measured using Jig method and Schneider technique are 12/52° and 8/44° respectively. Canal curvature average values measured using Jig method and Schneider method for maxillary teeth were 23.40° (±11.36) and 19.23° (±11.94) respectively. The smallest/largest average curvature angles measured using Jig method, Schneider technique were 9/70° and 5/72° respectively. The values of the canal curvature angle obtained during routine radiographs in clinics have lower curvature angle and higher radius values as compared to the values obtained by this innovative JIG technique. Therefore, a clinician should always keep in mind the difference while measuring the curvature angle on radiographs during root canal treatment.

Metode Balancing Jig Procedure pada Tab Elevator Pesawat Boeing 737-800 untuk Mengurangi Dampak Flutter

Primary flight control pada pesawat udara terdiri dari aileron, rudder dan elevator, Secondary flight control terdiri dari flaps, slats, spoiler dan trim tab. Pesawat sebelum terbang harus dipastikan semua flight control dalam keadaan balance. Jika tidak, maka flutter akan terjadi ketika pesawat tersebut mengudara. Flutter adalah salah satu fenomena aeroelastisitas, yaitu fenomena getaran yang mengakibatkan sayap pesawat terbang “mengepak” seperti sayap burung. Hal ini diakibatkan karena kombinasi efek kekakuan struktur sayap, aerodinamika serta inersia (berat) dari struktur. Untuk menghindari terjadinya flutter harus dilakukan balancing flight control, salah satunya pada Tab Elevator. Tab elevator sering disebut dengan trim tab pada elevator. Trim Tab tersebut melekat pada elevator yang terletak pada horizontal stabilizer. Meskipun trim tab merupakan secondary flight control, harus tetap dipastikan balance. Cara balancing tab elevator adalah dengan metode jig procedure, dimana tab harus dilepas terlebih dahulu. Balance atau tidaknya tab elevator ditentukan dari nilai Tab Assembly Moment (TAM). Hasil yang didapat dari penelitian ini adalah 15.22 lbfinch dan tab dikatakan balance, karena menurut Structural Repair Manual (SRM) Boeing 737-800 range maksimal nilai TAM adalah 15.48 lbfinch. Jika pada penelitian didapatkan hasil lebih dari 15.48 lbfinch, maka tab harus dikembalikan ke paint shop untuk dilakukan pengelupasan beberapa lapisan catnya agar mengurangi beban tab tersebut. Apabila pengurangan beban pada tab tidak bisa dilakukan lagi, maka Tab tersebut dianggap reject (tidak layak) dan harus diganti dengan yang baru.

Efficacy of various cleaning solutions on saliva-contaminated zirconia for improved resin bonding.

PURPOSEThis study aimed to investigate the efficacy of cleaning solutions on saliva-contaminated zirconia in comparison to air-abrasion in terms of resin bonding.MATERIALS AND METHODSFor saliva-contaminated airabraded zirconia, seven cleaning methods)-no contamination (NC), water-spray rinsing (WS), additional airabrasion (AA), and cleaning with four solutions (Ivoclean [IC]; 1.0 wt% sodium dodecyl sulfate [SDS], 1.0 wt% hydrogen peroxide [HP], and 1.0 wt% sodium hypochlorite [SHC])-were tested. The zirconia surfaces for each group were characterized using various analytical techniques. Three bonded resin (Panavia F 2.0) cylinders (bonding area: 4.5 mm2) were made on one zirconia disk specimen using the Ultradent jig method [four disks (12 cylinders)/group; a total of 28 disks]. After 5,000 thermocycling, all specimens were subjected to a shear bond strength test with a crosshead speed of 1.0 mm/minute. The fractured surfaces were observed using an optical and scanning electron microscope (SEM).RESULTSContact angle measurements showed that groups NC, AA, IC, and SHC had hydrophilic surfaces. The X-ray photoelectron spectroscopy (XPS) analysis showed similar elemental distributions between group AA and groups IC and SHC. Groups IC and SHC showed statistically similar bond strengths to groups NC and AA (P>.05), but not groups SDS and HP (P<.05). For groups WS, SDS, and HP, blister-like bubble formations were observed on the surfaces under SEM.CONCLUSIONWithin the limitations of this in vitro study, some of the cleaning solutions (IC or SHC) were effective in removing saliva contamination and enhancing the resin bond strength.

Effect of hydrophilicity on the compatibility between a dual-curing resin cement and one-bottle simplified adhesives.

To evaluate the effect of the hydrophilicity of adhesives on the compatibility between one-bottle simplified adhesives and a dual-curing resin cement. Three experimental and two commercial adhesives (All-Bond Universal, OptiBond Allin- One) with the same or similar pH and various degrees of hydrophilicity were tested in this study. Extracted human dentin was treated with each adhesive and bonded with a dual-curing resin cement (Duolink), which was either light cured or chemically (self) cured (n = 10). Shear bond strength was tested using the Ultradent jig method, and failure modes were determined using a stereomicroscope. Water contact angle (as a measure of hydrophilicity/-phobicity) was measured on a fully cured adhesive (n = 10). The data were analyzed statistically by ANOVA and Tukey's test. The quantitative relationship between the hydrophilicity and bond strength differences was analyzed (confidence level 95%). Among the experimental adhesives, differences in bond strengths between light-curing and self-curing modes were larger for the more hydrophilic adhesives. For the commercial adhesives, Optibond All-in-One had a lower contact angle than All-bond Universal (p < 0.05). Bond strength (MPa) values for Optibond All-in-One and All-bond Universal were 29.6 and 31.5, respectively (light cured), and 1.9 and 30.0, respectively (self-cured). Adhesive failure was a predominant mode for all adhesives except for All-Bond Universal. Regression analysis indicated a linear correlation between adhesives' hydrophilicity and bond strength differences (p < 0.05). The more hydrophilic adhesives were less compatible (larger bond strength differences between different curing modes) with this dual-curing resin cement. All-bond Universal is more hydrophobic than Optibond All-in-One and it is compatible with this self-/dual-curing resin cement.

Influence of carbodiimide cross-linking on bond strength to radicular dentin

Purpose: The purpose of this study is to measure shear bond strength of universal adhesives on completely demineralized dentin (overly etched dentin). Methods and materials: Human dentin was polished and etched with 37%-phosphoric acid etchant. The control groups were etched normally (15 s, once). The other groups were etched twice or four times (15 s each time, rinse with DI water after etching each time in order to completely demineralized dentin and remove calcium salts). The etched dentinwas then treated with universal adhesives according to manufacturer’s instructions. Shear bond strength (n=6) on dentin was tested using the ultradent jig method (bonding area 4.5mm2). Resin composite material (Duolink, Bisco) was used to fabricate the posts (2mm high, light-cured 40 s/500mW/cm2). The specimens were then stored in de-ionized water (37 ◦C/24h), and testedby Instron tester (crosshead-speed1mm/min). Thedata were analyzed statistically by two-way ANOVA and Student-t tests. Results: The results are shown in Table 1.

The Footprint method to assess transmalleolar axis

Torsional deformities of the lower extremities are a common reason for an orthopaedic consultation and are also part of the evaluation of a patient in gait analysis. This study assessed the level of agreement between, and the repeatability of, the Footprint method and two other methods (Prone and Jig) of measuring the transmalleolar axis (TMA) clinically. The Footprint method measures the TMA as the patient sits by projecting the position of the malleoli downwards onto lined paper while the lines of the paper are aligned with the knee axis. The Prone method projects the position of the malleoli upwards onto the sole of the foot and this is related to the visually estimated knee axis. The Jig method uses a tropometer to relate the angle between the tibial tubercle and the two malleoli. Two assessors measured twelve subjects using the three methods and six subjects were re-measured approximately 1 week later for repeatability. There was poor agreement between the three methods but the Footprint method was the most repeatable (coefficient of repeatability: 5.4). One observer then assessed the repeatability of the effect of simulated equinus on the Footprint method in 10 normal subjects on 2 separate occasions 1 week apart. Equinus was obtained by having the subjects sit and firstly extend their knee and place the foot on the floor and secondly by placing the foot under consideration on a wedge. Both conditions introduced an offset into the measurement of the TMA when compared to the measurements with the ankle at neutral in the same subjects. The reliability of the Footprint method was then assessed using 10 inexperienced observers who measured nine normal subjects each on 2 separate occasions and their results compared with those from an experienced observer. The inexperienced observers were less repeatable than an experienced observer (coefficients of repeatability 9.2 and 6.9, respectively). We recommend that different methods of measuring TMA should not be used interchangeably in clinical practice. The Footprint method was the most repeatable of the three methods tested and can be used for patients who have fixed equinus but the measurement was less repeatable when used by inexperienced observers.

Determinant assembled stowage bins—a case study

AbstractMost commercial aircraft interior stowage bins are assembled using jigs. These assembly jigs are built to strict tolerances to ensure that the assemblies created in them will perform properly. Over the past decade, commercial aircraft structures assembly has been in transition from a method of assembly jig location to a method of part to part indexing, also known as Determinant Assembly. This method is now being investigated for accurate location of composite sandwich panels and metal attachments for commercial aircraft interiors. A background on Determinant Assembly (DA) as it has developed in structures is introduced. Several methods of coordinating composite sandwich panels to metal parts are discussed. Data that substantiates the use of these methods to maintain the prescribed tolerances is presented graphically. The results of building prototype parts using these techniques are presented. The process capability for DA assembled stowage bins is predicted using Variation Simulation Analysis, and those predictions are compared to results obtained with the current assembly jig method.

Comparing the error of the improved Bridge Gauge Transverse Method and Jig Method for circularity measurement

This paper presents three procedures for measuring and calculating the circularity of a submarine pressure hull. The Bridge Gauge Transverse Method is studied, detailed and improved. Improvements in the gauge itself are proposed and a new out-of-roundness mathematical calculation routine is developed. A Qualification Procedure to determine the calculating method effective accuracy is presented. The quality, utility and use of the proposed improved process during the submarine pressure hull fabrication steps is discussed, in comparison with the Jig Method.

Steel–Car Construction at the Angus Shops of the Canadian Pacific Railway, Montreal

Abstract In 1909 the Canadian Pacific Railway, to meet the increasing severity of modern traffic requirements, originated a box car having its entire frame built of steel. The production of such equipment in quantity necessitated the erection of an additional shop for the fabrication of the steelwork, and the structure built embodied in its arrangement many novel features for the rapid handling of material to and from the machines and also during the various stages of assembly. The present paper describes this shop very completely, giving particulars regarding its layout, crane facilities, machine equipment, etc. The various machining operations and the jig method of car assembly, first put into practice at the Angus shops, are presented in detail, and the methods used in the final erection and finishing of cars are dealt with at some length.