Rigid Wire Research Articles

Effect of different splinting methods and fixation periods on root development of autotransplanted immature third molars

The aim of the present study was to assess the influence of suture splinting for 1 week or rigid fixation for 4 weeks on final root length, root length increment, and mobility of autotransplanted immature third molars. The sample consisted of 63 patients with a total of 65 transplanted immature third molars. All transplants had reached one-half (n = 29) to three-fourths (n = 36) of their expected root length. In 24 of the transplants, postoperative fixation was carried out with a rigid acid-etch composite and wire splint for 4 weeks (rigid group), and in 41 transplants, with a suture splint for 1 week (suture group). The fixation method depended on the initial stability of the transplants. All transplants were followed up clinically and radiologically for a mean period of 3.9 years. Transplants in the rigid group revealed a significantly lower final root length ( P = .002) and root length increment ( P = .001) than those in the suture group. The differences were found to be more pronounced in transplants at earlier developmental stages. No differences were found in transplant mobility. The results of the present study indicate that prolonged rigid fixation of autotransplanted immature third molars has a significantly negative influence on final root length and root length increment, especially in transplants at earlier developmental stages.

A new design of wire locators for drift tubes

Every position-sensitive wire detector needs to solve the problem of wire positioning with a defined accuracy all over its sensitive volume. In particular, thin-walled drift tubes ("straws"), which are currently being attached to large detector units of several tens of square meters of surface, need to be equipped with wire locators along their signal wires. A wire locator has been developed together with an insertion device, especially for medium-sized drift tube systems, which significantly reduces the production time and avoids the danger of applying epoxy glue to the signal wire. The wire locator is being inserted in one single time-saving production step together with the signal wire itself. The proposed design is being compared to the rigid wire locators in use in the COMPASS straw tracking system at CERN. The investigation comprises both wire-centering capability and influence on the efficiency of adjacent detector regions, demonstrating the competitive performance of the proposed new system. Its sufficient mechanical reliability could be shown by means of an X-ray tomography; the attractively small influence on the drift field was determined in a test measurement using a silicon tracking system in a hadron beam.

An Explanation for the High-Frequency Elastic Response of Dilute Polymer Solutions

The behavior of polymer molecules in dilute solutions under high-frequency oscillations is revisited, with consideration given to the barriers to bond rotation that we argue can make the chain dynamically rigid at high frequency. Thus, the dynamical Kuhn length of the chain exceeds the static one, and the chain at high frequencies acts like a freely jointed chain of “bent rigid wires” in which each bent rigid wire is a “dynamical Kuhn length” containing many static Kuhn lengths connected together in a rigid random walk. We show that this model is consistent with anomalous high-frequency behavior of polystyrene solutions under shear observed by Schrag and co-workers1-3 and Amelar et al.4 and predicts that there is a minimum “spring” size corresponding roughly to exp[ΔEa/(3ν + 1)kBT] Kuhn steps that will behave elastically at high frequencies, where ΔEa is the barrier to bond rotation, and ν = 0.5−0.6 is the Flory exponent.

Sequential folding of a rigid wire into three-dimensional structures

Nitinol wire is used to encode a three-dimensional structure in a linear chain. The folding of the structure progresses sequentially along the rigid wire from one end using only short-range forces. Three different shapes are constructed, an overhand pseudoknot, a protein structure with α-helices, and a protein structure without α-helices. The overhand pseudoknot was designed to be noncommutative so that forward folding along the chain results in the correct structure whereas reverse folding does not. The manipulation of nitinol wire structures leads to simple empirical rules for folding for noncommutative pseudoknots. Suggestions for additional noncommutative pseudoknot structures that can be designed both from wire and from DNA or RNA are given. The folding also can be accomplished using ordinary stiff wire. The folding of the wire provides an intuitive way to visualize sequential folding freed from a lattice.

Stability of skeletal class III malocclusion after combined maxillary and mandibular procedures: rigid internal fixation versus wire osteosynthesis of the mandible

Purpose The aim of this study was to evaluate skeletal stability after double-jaw surgery for correction of skeletal Class III malocclusion to assess whether there were any differences between wire and rigid fixation of the mandible. Patients and methods Thirty-seven Class III patients had Le Fort I osteotomy stabilized with plate and screws for maxillary advancement. Bilateral sagittal split osteotomy for mandibular setback was stabilized with wire osteosynthesis and maxillomandibular fixation for 6 weeks in 20 patients (group 1) and with rigid internal fixation in 17 patients (group 2). Lateral cephalograms were taken before surgery, immediately after surgery, 8 weeks after surgery, and 1 year after surgery. Results Before surgery, both groups were balanced with respect to linear and angular measurements of craniofacial morphology. One year after surgery, maxillary sagittal stability was excellent in both groups, and bilateral sagittal split osteotomy accounted for most of the total horizontal relapse observed. In group 1, significant correlations were found between maxillary advancement and relapse at the posterior maxilla and between mandibular setback and postoperative counterclockwise rotation of the ramus and mandibular relapse. In group 2, significant correlations were found between mandibular setback and intraoperative clockwise rotation of the ramus and between mandibular setback and postoperative counterclockwise rotation of the ramus and mandibular relapse. No significant differences in postoperative skeletal and dental stability between groups were observed except for maxillary posterior vertical position. Conclusions Surgical correction of Class III malocclusion after combined maxillary and mandibular procedures appears to be a fairly stable procedure independent of the type of fixation used to stabilize the mandible.

PG canine retraction spring

PG canine retraction spring was introduced to the orthodontic profession way back in 1985 by Poul Gjessing; it was not widely used till interest in it was renewed in recent years because of its adaptability to the now commonly used 0.018” pre-adjusted edgewise appliance system. The efficient design as well as the relatively rigid stainless steel wire, lends good stability to this retraction spring for use in frictionless orthodontic mechanics. Canine retraction is a very important step in most orthodontic procedures involving extraction of premolar teeth and is usually carried out by two methods: 1) Retracting canines by sliding along a base wire (Frictional mechanics) 2) Retracting the canine with a specially designed spring attached to it without any base arch wire for the canine to slide on (Frictionless mechanics) Contemporary Orthodontics by Proffit [1] describes the PG spring to be the most efficient current design for frictionless canine retraction. Rectangular stainless steel wire with overlapping ovoid loops provide good stability, required moment-force ratio and good load deflection rates. It is constructed in the readily available 0.016″x0.022″ stainless steel wire and can be easily placed in the routinely used 0.018” brackets. Construction and placement is easy and so is the activation. Its advantage as compared to other retraction springs is the fact that it can be economically made and used within the routine inventory of an average orthodontic clinic. Disadvantages are the same as in any retraction spring, in not being failsafe in case of accidental distortion and being liable to irritate the sulcular mucosa at least in the initial few days. Construction: The PG spring [2, 3, 4] is made in 0.016″x.022″ stainless steel rectangular wire. It has gingivally directed overlapping double helices, ovoid in shape, 10mm in height and 5.5mm at its widest part (Fig 1). It also has a small occlusal helix 2mm in diameter. The wire is bent in such a way that the smaller end of the wire is continuous with the occlusal helix. This portion is the canine part and would fit into the canine bracket. As it comes out of the occlusal helix, it is given a 15° gingival turn. After forming the gingivally directed double helices, the longer arm of the wire is the one which is meant for engaging the premolar bracket and the molar tube; this being the molar portion. This posterior molar arm as it exits from the double ovoid loops is turned gingivally such that the wire makes an angle of 12° till approximately the second premolar bracket and then turned up at an increased total angulation of 30° as shown in Fig 1. This portion is also given an anti-rotation bend of 60° towards the canine tooth and then this bend after traversing the width of the spring is curved back in an exactly opposite direction of the initial bend decreasing this to a final 35° (Fig 2). Fig. 1 Right upper PG spring (palatal view) Fig. 2 Right upper PG spring (occlusal view) Placement and activation: The anterior end emerging out from the smaller helix is placed as close as possible to the canine bracket and the front end is cinched. The posterior end is placed into the second premolar bracket and then into the 1st molar tube. The spring is pulled back till the double ovoid gingival loops open by 1mm and cinched back. This gives an approximate force of 160 grams. A retraction of 1.5 mm is expected in one month. The PG spring in use is shown in Fig. 3, Fig. 4. Fig. 3 PG canine retraction spring before retraction Fig. 4 PG canine retraction spring after retraction The spring induces bodily movement of teeth and anchorage, reinforcement by a Nance button or headgear is needed in moderate to high anchorage cases. A prerequisite before placing this spring is good rotational correction as well as levelling and alignment of the three teeth involved.

Energy Transport in CdSe Nanocrystals Assembled with Molecular Wires

Continuous-wave photoluminescence studies on CdSe nanocrystals assembled with oligo-p-(phenylene-ethynylene)n-dibenzylthiols (n = 0,1,3) indicate long-range resonant energy transfer can be tuned by size-dependent control of the weak electromagnetic dipole−dipole coupling of the donor (molecular wire) and the acceptor (nanocrystal). These micron-scale free-standing inorganic−organic composite structures are composed of CdSe in the strongly confined regime with diameters between 2.8 nm to 8.0 nm assembled with rigid molecular wire lengths of 1.3 nm, 1.9 nm, and 3.1 nm. Evidence is presented which supports the possibility that interchain interactions of molecular wires within the assembly form two additional species that participate in the energy transfer process, dimers and aggregate excitons. Dimer states act as intermediate states for the migrating molecular exciton, and are selectively quenched by quantized CdSe electronic transitions (1S3/2−1Se, 1P3/2−1Pe), while aggregate excitons act as emissive excit...

A151 Noise Reduction of an Under-expanded Supersonic Jet Using a Rigid Wire Device

This paper presents an experimental study to explore the noise reduction of an under-expanded supersonic jet. As a novel method to obtain the noise reduction, a rigid wire is inserted into the under expanded supersonicjet stream. The experimental results show that the wire device significantly changes the shock and acoustic wave structures, leading to substantial noise reduction, compared with the under expanded jets without the wire device. According to the jet noise measurement, the + type wire device leads to the overall sound intensity reduction of about 15dB.

A modified mandibular ramus osteotomy for orthognathic surgery

Several procedures have been described for correction of orthognathic deformities of the mandible. Currently, the bilateral sagittal split osteotomy (BSSO) maintains its popularity because of its versatility and its amenability to rigid fixation techniques. The distal segment of the mandible can be repositioned in all planes of space, and the bony interface along the osteotomy results in predictable healing. However, there are well-known disadvantages to the procedure, which include neurosensory disturbance, 1 Pratt CA Labial sensory function following sagittal split osteotomy. Br J Oral Maxillofac Surg. 1996; 34: 75 Abstract Full Text PDF PubMed Scopus (43) Google Scholar , 2 Posnick J Alteration in facial sensibility in adolescents following sagittal split and chin osteotomies of the mandible. Plast Reconstr Surg. 1996; 97: 920 Crossref PubMed Scopus (67) Google Scholar , 3 Lemke RR Effects of hypesthesia on oral behaviors of the orthognathic surgery patient. J Oral Maxillofac Surg. 1998; 56: 153 Abstract Full Text PDF PubMed Scopus (26) Google Scholar , 4 Jacks SC A retrospective analysis of lingual nerve sensory changes after mandibular bilateral sagittal split osteotomy. J Oral Maxillofac Surg. 1998; 56: 700 Abstract Full Text PDF PubMed Scopus (50) Google Scholar , 5 Fujioka M Comparative study of inferior alveolar disturbance restoration after sagittal split osteotomy by means of bicortical versus monocortical osteosynthesis. Plast Reconstr Surg. 1998; 102: 37 Crossref PubMed Scopus (45) Google Scholar , 6 Blomqvist JE Sensibility following sagittal split osteotomy in the mandible: A prospective clinical study. Plast Reconstr Surg. 1998; 102: 325 Crossref PubMed Scopus (52) Google Scholar , 7 August M Neurosensory deficit and functional impairment after sagittal ramus osteotomy: A long-term follow-up study. J Oral Maxillofac Surg. 1998; 56: 1231 Abstract Full Text PDF PubMed Google Scholar , 8 Westermark A Inferior nerve function after mandibular osteotomies. Br J Oral Maxillofac Surg. 1998; 36: 425 Abstract Full Text PDF PubMed Scopus (174) Google Scholar , 9 Westermark A Inferior alveolar nerve function after sagittal split osteotomy of the mandible: Correlation with degree of intraoperative nerve encounter and other variables in 496 operations. Br J Oral Maxillofac Surg. 1998; 36: 429 Abstract Full Text PDF PubMed Scopus (139) Google Scholar condylar displacement, 10 Magalh-aes AE Changes in condylar position following bilateral sagittal split ramus osteotomy with setback. Int J Adult Ortho Orthognath Surg. 1995; 10: 137 PubMed Google Scholar , 11 Van Sickels JE Condylar torque as a possible cause of hypomobility after sagittal split osteotomy: Report of three cases. J Oral Maxillofac Surg. 1997; 55: 398 Abstract Full Text PDF PubMed Scopus (20) Google Scholar , 12 Nishimura A Positional changes in the mandibular condyle and amount of mouth opening after sagittal split ramus osteotomy with rigid or nonrigid osteosynthesis. J Oral Maxillofac Surg. 1997; 55: 672 Abstract Full Text PDF PubMed Scopus (33) Google Scholar , 13 Van Sickels JE Condylar position with rigid fixation versus wire osteosynthesis of a sagittal split advancement. J Oral Maxillofac Surg. 1999; 57: 31 Abstract Full Text PDF PubMed Scopus (32) Google Scholar and unfavorable splits. 14 Martis CS Complications of the mandibular sagittal split osteotomy. J Oral Maxillofac Surg. 1984; 42: 101 Abstract Full Text PDF PubMed Scopus (146) Google Scholar , 15 Van Sickels JE Jeter JE Theriot BA Management of an unfavorable lingual fracture during a sagittal split osteotomy. J Oral Maxillofac Surg. 1985; 43: 808 Abstract Full Text PDF PubMed Scopus (26) Google Scholar , 16 Turvey TA Intraoperative complications of sagittal osteotomy of the mandibular ramus: Incidence and management. J Oral Maxillofac Surg. 1985; 43: 504 Abstract Full Text PDF PubMed Scopus (104) Google Scholar , 17 Marquez IM Modification of the sagittal split osteotomy to avoid unfavorable fracture around impacted third molars. Int J Adult Ortho Orthognath Surg. 1998; 13: 183 PubMed Google Scholar

A novel approach to facilitate dilation of complex non-traversable esophageal strictures by efficient wire exchange using a stent pusher

Background: Dilation of non-traversable complex strictures is frequently difficult. For a tight stricture, over-the-wire dilation is difficult using a flexible biliary guidewire as opposed to a more rigid guidewire with a spring tip made for use with polyvinyl over-the-wire dilators (Savary). However, passage of the more rigid, spring-tipped wire is not always possible. A new method is discussed here whereby a biliary guidewire is exchanged consistently with a rigid, spring-tipped wire to facilitate dilation of complex strictures. Methods: The wire exchange was carried out using a 10F stent pusher. The latter is readily available and semi-rigid, and its large lumen easily accommodates a Savary guidewire. Furthermore, because it can be passed through an endoscope, it can be passed without difficulty through an extremely tight stricture because the device does not buckle in the proximal esophagus or mouth. Results: Dilation was successful in 6 patients using this technique with no complications. Four patients required placement of the stent pusher through a therapeutic endoscope. Conclusion: A method is described that facilitates dilation of complex, tight esophageal strictures by exchange of a flexible biliary guidewire with a more rigid Savary wire using a stent pusher.

Condylar position with rigid fixation versus wire osteosynthesis of a sagittal split advancement

Condylar position with rigid fixation versus wire osteosynthesis of a sagittal split advancement

Condylar position with rigid fixation versus wire osteosynthesis of a sagittal split advancement

Purpose: In this randomized clinical study, two groups of patients who underwent a bilateral sagittal split osteotomy and either wire osteosynthesis or rigid fixation were compared. Patients and Methods: Cephalometric radiographs obtained before surgery, immediately after surgery, and at 8 weeks, 6 months, and 1 and 2 years after surgery were available for 125 of these patients, 63 with wire fixation and 62 with rigid fixation. All were traced by an independent examiner, and vertical and horizontal changes in condylar position were recorded for each period. Results: Condylar movement was slightly different with the two fixation techniques beyond 8 weeks postsurgery, but the ultimate position of the condyle was not different. The condyles in both groups moved posterior and superior. There initially was a correlation between the amount of advancement and the amount the condyle moved inferior in both groups, but this diminished with time. In addition, there was a weak but significant positive relationship between forward rotation of the proximal segment and superior condylar position immediately after surgery, which did not exist at later periods. Conclusions: Whether wire osteosynthesis or rigid fixation was used, the ultimate condylar position was posterior and superior after a bilateral sagittal split osteotomy to advance the mandible. No single factor could be identified to account for this change. It is suggested that change in mechanical load may have resulted in remodeling and adaptation of the condyles.

Proper and improper tension band fixation exemplified by patellar fracture

The tension band, performed with rigid cerclage wire, is known worldwide as a standard operation technique for the patella fracture as well as for all fractures gaping under strong muscular tensile forces. Eccentricity of power input and transformation of tension into pressure forces are its theoretical rationale. This is a contradiction to the knowledge of engineers. Its disadvantages are: tilting and rolling-out, steps and gaps in the cartilage surface and distraction. Rigid cerclage wire is not a tensile instrument. Corresponding to this, the results are only mediocre. Here we describe a static tension band principle, consisting of axial power input by 2 lateral cables. The very good and good X-ray and functional results amount to 78%, far exceeding the rate with the conventional wire tension band.

Management of mandibular fractures: A comparative analysis of rigid internal fixation and steel wire osteosynthesis. (English-Portuguese)

Management of mandibular fractures: A comparative analysis of rigid internal fixation and steel wire osteosynthesis. (English-Portuguese)

Management of mandibular fractures: A comparative analysis of rigid internal fixation and steel wire osteosynthesis. (English-Portuguese)

(Reprint requests to Dr. R. L. Cruz, Rua Visconde Silva 52, sala 703, CEP: 22271-090, Botafogo RJ, Brazil)

外傷による脱落永久歯３６歯の再植に関する臨床的検討

We performed a clinico-statistical study of 36 permanent teeth that were replanted after being avulsed by trauma. We found that the most frequently involved age group was 6 to 12 years old, and the average age was 13.8 years old. The most frequent causes were falling dropping, sports, and playing, and the maxillary central incisors were the most frequently avulsed teeth. Avulsed teeth were most often air-dried. The average period between avulsion and replantation was 4.9 hours.The most common type of splinting was a rigid wire fixation using an arch bar, and the average period of splinting was 54.4 days.As for the outcome of replantation, most root resorption occurred within 1 year after replantation and root resorption was closely related to the period between avulsion and replantation. The replanted teeth were functional after replantation and the 5-year survival rate was 63.6%. The 5-year rate of root resorption was 81.8%.The results suggest that every effort should be made to preserve avulsed teeth even when conditions are unfavorable for replantation.

Comparison of Rigid Plate versus Wire Fixation in the Management of Zygoma Fractures

We evaluated retrospectively 101 patients to assess clinically the results of fixation methods on isolated unilateral zygoma fractures (mean follow-up 3.2 years). All patients were examined by an investigator who was blinded to the initial fixation method. Ninety-two patients were treated with wire or plate fixation alone. The major clinical parameters assessed were globe position abnormalities (enophthalmus and dystopia), malar projection, and cheek sensation. Rigid plate fixation achieved statistically better long-term malar symmetry (p = 0.002) and approached statistical significance in the achievement of more normal globe position (p = 0.06) compared with wire fixation alone. Cheek sensation showed a nonsignificant trend (p = 0.13) toward improvement with plate fixation. Other parameters that were evaluated were anatomic location of fixation points, number of fixation points, surgical approach and exposure, and breakdown of fixation dates by specialty. None of these factors showed any significant influence on outcome. The present study confirms what we have known to be true from our clinical experience--that rigid internal fixation is superior in minimizing or preventing long-term sequelae of facial fractures.

An electrostatic ion guide for efficient transmission of low energy externally formed ions into a Fourier transform ion cyclotron resonance mass spectrometer

A new method for transmitting externally formed ions into an ICR ion trap is demonstrated. In an electrostatic ion guide, a potential difference is applied between a conductive cylinder and a rigid wire suspended along the central axis of the cylinder. The cylinder is then positioned between an ion source located outside the bore of superconducting solenoidal magnet and an ion trap located at or near the center of the solenoid. simion simulations predict that low-energy ions entering the ion guide will spiral around the central wire and pass through the fringe of the magnet to reach the ICR ion trap. The theoretical predictions are borne out by experiments in which Na + and K + ions from a thermionic emitter are transmitted with high efficiency through the fringe field of the magnet to the ICR ion trap. Mass resolving power of 285 000 for K + is shown. The electrostatic ion guide offers the advantages that: (a) a wide range of low-energy external sources (e.g., fast-atom on fast-ion bombardment, electrospray, glow discharge, etc.) may be used; (b) prior acceleration of the ions along the magnetic field direction (and subsequent deceleration to slow the ions on entry into the ICR ion trap) is not required; (c) ions are focused along magnetic field lines once the ions have passed through the magnetic fringe field; and (d) ions formed initially off axis are efficiently captured and transmitted by the ion guide without additional focusing.

Evaluation of Escape Modifications in Traps for Prawn, Pandalus platyceros

Experimental fishing was done in 1986 to evaluate variables considered important in developing escape modifications for the prawn, Pandalus platyceros, trap fishery in British Columbia. Three major trap categories were used: flexible nylon mesh, rigid wire mesh, and solid sided. The efficacy of escape modifications depended upon the size of openings, the type of construction material, the placement of the modification on the trap, and soak time. The 44-mm web and wire material used for modifications allowed for escapement of prawns well above the 30.0-mm carapace length legal size limit. The rigid wire mesh used in escape modifications retained smaller prawns than did similar-sized flexible nylon mesh. In partially modified traps, escape material on the side/bottom combination was more effective for escapement than when just on the bottom or in the tunnels of the trap. Soak time was important in some traps which had escape material in ineffective locations. In these cases, longer soak times allowed the small prawns time to find their way out of the traps.

Investigation of the performance of two types of the Doppler catheter in vitro.

There is considerable interest in the use of Doppler catheters for measuring coronary flow reserve in humans. Two types are currently available, these being models having side-mounted or tip-mounted transducers. The performance of these catheters was carefully observed in Silastic tubing perfused with blood by a roller pump. Each catheter was used with two types of positioning wire: a rigid wire and a standard J-tip guidewire. Linear regressions of velocity vs. flow rate were performed. Both catheters performed well with the rigid wire (r greater than or equal to 0.992). When used with the J-tip, the end-mounted catheter suffered decreased performance because of positioning difficulties, while the side-mounted catheter performance was within 6% of the ideal. Measurements made with the side-mounted catheter at low flow rates underestimated the expected response for forward flow. Because of the ease of positioning, the side-mounted catheter is judged to be more useful in measuring flow ratios.