ABSTRACT
Two methods for orthodontic bonding were used to attach brackets to 48 incisor and 48 premolar extracted human teeth. Half of the sample teeth were bonded by means of a highly filled bis-GMA adhesive by a direct placement method. The remaining teeth were bonded with the same adhesive by an indirect method suggested by Thomas. Actual chairside bonding procedures were simulated with regard to the timing and manipulation of adhesives and attachments. Tensile and shear bond strengths are reported for each of the two methods of bracket attachment.
Subject(s)
Dental Bonding/methods , Dental Stress Analysis , Orthodontic Appliances , Bisphenol A-Glycidyl Methacrylate , Composite Resins , Humans , Polymethacrylic Acids , Tensile StrengthABSTRACT
Aligning, leveling, and anterior torque control of teeth from the onset of treatment is suggested with thermal ni-ti rectangular low stiffness wires. Before and after superimpositions show the degree that torque control was achieved on four clinical patients.
Subject(s)
Dental Alloys , Nickel , Orthodontic Appliances , Orthodontic Wires , Titanium , Tooth Movement Techniques/methods , Adolescent , Elasticity , Extraoral Traction Appliances , Hot Temperature , Humans , Malocclusion/therapy , Pilot Projects , Stainless Steel , Stress, Mechanical , Surface Properties , Tooth Movement Techniques/instrumentationABSTRACT
A preliminary study was conducted to demonstrate the usefulness of the combined technique of differential scanning calorimetry (DSC) and mechanical testing for the shape memory metals of 54NiTi and 53NiTiCo(3%) alloys. The DSC technique was used to measure precise transformation temperatures and the amount of thermal energy required for the corresponding phase transformation. The degree of plastic deformation by bending and the effect of alloying (such as Co) were studied with combined DSC and mechanical property measurements.
Subject(s)
Alloys , Nickel , Orthodontic Appliances , Orthodontic Wires , Titanium , Calorimetry, Differential Scanning , Elasticity , Microscopy, Electron, Scanning , Stress, Mechanical , Tensile StrengthABSTRACT
Today's orthodontic practice includes a larger proportion of adults. Because many of these adults have crown and bridge restorations fabricated from porcelain or gold, the orthodontist must use methods that permit the attachment of orthodontic brackets to porcelain and nonprecious metal or gold. A bracket may be placed on single-unit crowns of porcelain or gold, but banding becomes difficult. Thus bonding the orthodontic bracket to the restoration provides a satisfactory alternative. This clinical report describes several techniques for bonding orthodontic brackets to porcelain or gold surfaces, and some suggestions for removal of bonded brackets.
Subject(s)
Dental Bonding/methods , Dental Porcelain , Gold Alloys , Orthodontic Appliances , Chemical Phenomena , Chemistry, Physical , Humans , Silanes , Surface PropertiesSubject(s)
Composite Resins , Dental Bonding , Orthodontic Appliances , Chemical Phenomena , Chemistry, Physical , Light , PolymersABSTRACT
There are two frequently used methods of aligning malposed teeth by means of an arch wire. The first method is to deflect and tie the arch wire, which has a low modulus of elasticity, into the deepest part of the bracket slot. This low-modulus arch wire is not permanently deformed, and the elastic forces in it return the arch wire (which is tied to the bracket on the tooth) to its preformed shape. The second method is to stretch an elastic material (for example, Unitek ligature threads, Unitek Alastik modules, Ormco power threads, or Ormolast ligature modules) from the bracket tie wings to a preformed stiff arch wire which has a high modulus of elasticity and the teeth move from their malposed position to the stiff arch wire form. The objective of this investigation was to stretch a thermodynamic nitinol wire from 8 percent to 12 percent of its original length and measure the shrinkage of the wire in length. If the quantity of shrinkage of a 0.010-inch nitinol ligature type of wire were great enough, the second method of moving teeth to a stiff preformed arch wire by employing the thermodynamic nitinol stretched wire as a "wire rubber band" could be used to move teeth. This could serve as a possible alternative to Alastik and elastic modules in which there is a great deal of inherent force decay and permanent deformation. When the thermodynamic nitinol wire was heated through its transition temperature range, three different magnitudes of shrinkage occurred. The first was less than 1.0 percent of the original stretched length of the wire, the second was between 6 percent and 7 percent of the original stretched length of the wire, and the third was approximately 1.0 percent.
Subject(s)
Alloys , Orthodontic Appliances , Orthodontic Wires , Cobalt Radioisotopes , Dental Alloys , Surface Properties , Temperature , Tensile StrengthSubject(s)
Alloys , Orthodontic Appliances , Orthodontic Wires , Stainless Steel , Chemical Phenomena , Chemistry, Physical , Corrosion , Electrolysis , Nickel , Surface Properties , TitaniumSubject(s)
Alloys , Malocclusion, Angle Class I/therapy , Malocclusion/therapy , Orthodontic Appliances , Stainless Steel , Adult , Female , Humans , Nickel , TitaniumABSTRACT
When the Siamese edgewise bracket with continuous arch wires is used, it does not always follow that with 100 to 150 Gm. of applied force only the canine and not the buccal segment or anchor unit will move. Conversely, it does not always follow that with 400 to 500 Gm. of applied force only the buccal segment or anchor unit will move forward and the canine will not move. With the sliding mechanics of this study, the percentage of greater rates of tooth movement happening coincident with greater forces was found to be 0.86. With the edgewise bracket and sliding mechanics, the curves showed that, in general, reciprocal forces cause reciprocal tooth movement with varying and relative rates of space closure. Subjectively, no relationship was found between pain and increased forces; that is, pain in this study was found just as often on the side with 100 to 150 Gm. of applied force as on the side with 400 to 500 Gm. of applied force. This is not to say that there is not more tissue damage found with the use of heavier forces.
Subject(s)
Dental Stress Analysis , Orthodontic Appliances , Tooth Movement Techniques , Biomechanical Phenomena , Evaluation Studies as Topic , Female , Humans , Malocclusion, Angle Class I/therapy , Stress, MechanicalABSTRACT
Closing spaces is done either by translation of the edgewise brackets over an archwire or by the use of closing loops of some common design. This investigation suggests the concept of the further refinement of the "wire rubber band" as a means of closing spaces. Advantages of such a wire hypothetically would be to level the dentition, align the dentition, and condense spaces in the dentition with only one or two stretched nickel titanium wires having the proper temperature transition range (TTR). The temperature of the mouth would make such wires return to their original prestretched length. A correctly-sized wire would have sufficient stiffness at mouth temperature, and it would be kept at or above its TTR. The system eliminates friction from edgewise bracket translation and also the use of many auxiliary closing devices as well as reducing the number of archwire changes, thus saving chairside time.
