IJPCDR Elastics and Elastomeric in Orthodontics Practice REVIEW ARTICLE Elastics and Elastomeric in Orthodontics Practice 1Sagar Mapare, 2Kanish Bansal, 3Ranjit Pawar, 4Richa Mishra, 5Ashutosh Sthapak, 6Sayed F Khadri ABSTRACT provides the clinician with the ability to correct both Elastics and elastomeric are an important part of orthodontic anteroposterior and vertical discrepancies. treatment with patients’ cooperation; they are used for Both natural rubber and synthetic elastomers are correction of anteroposterior and vertical discrepancies; there widely used in orthodontic therapy. Naturally produced are many types of elastics placement in relation with treatment latex elastics are used in the Begg technique to provide requirements. Elastics can be classified in many ways: intermaxillary traction and intramaxillary forces. Syn- according to the material, their availability, their uses, and force. Elastomer is a general term that encompasses materials that, thetic elastomeric materials in the form of chains find their after substantial deformation, rapidly return to their original greatest application with edgewise mechanics where they dimensions. Natural rubber is the first known elastomeric, are used to move the teeth along the arch wire. used by the ancient Incan and Mayan civilizations. Rubber-like The links of chain fit firmly under the wings of an materials that are made from chemicals were called synthetic edgewise bracket so that chain elastomers also serve to rubber because they were intended as substitutes for natural rubber. replace metal as the ligating force that holds the arch The types of elastic based on their use are class I, II, III, wire to the teeth. Since they are so positively located on palatal, lingual, cross, etc. the brackets, it is usual for the chains to remain in situ Keywords: Elastics, Elastomeric, Natural and synthetic rubbers. until replaced by the orthodontist at the next visit of the patient. This routine differs from that usually followed How to cite this article: Mapare S, Bansal K, Pawar R, Mishra R, Sthapak A, Khadri SF. Elastics and Elastomeric in for latex elastics, which are changed by the patient every 1,2 Orthodontics Practice. Int J Prev Clin Dent Res 2018;5(2):S21-30.1 or 2 days. The use of latex elastics in clinical practice is predicted Source of support: Nil on force extension values given by the manufactures Conflict of interest: None for different sizes of elastics. The standard force index employed by suppliers indicates that at 3 times the INTRODUCTION original lumen size, elastics will exert the force stated on Elastics and elastomeric are routinely used as an active the package. component of orthodontic therapy. Elastics have been a From a clinicians’ point of view it would be mandatory valuable adjunct of any orthodontic treatment for many to know not only the clinical aspect of these elastics but years. Their use, combined with good patient cooperation, also their basic properties, in order to extract the most out of these polymers.2,3 1Professor, 2,3Reader, 4,6Postgraduate Student, 5Senior TERMINOLOGY Lecturer Force: It is defined as an act upon a body that changes 1,3 Department of Orthodontics and Dentofacial Orthopaedics or tends to change the state of rest or the motion of that Hedgewar Dental College, Hingoli, Maharashtra, India body. Though defined in units of Newtons it is usually 2 Department of Orthodontics and Dentofacial Orthopaedics measured in units of grams or ounce. Maharana Pratap College of Dentistry and Research Center Gwalior, Madhya Pradesh, India Elastic: It is defined as the ability of a substance to return to its original length or shape after being stretched. 4Department of Orthodontics and Dentofacial Orthopaedics Chhattisgarh Dental College and Research Institute Rajnandgaon Elasticity: The property of a substance that enables it to Chhattisgarh, India change its length, volume, or shape in direct response to 5Department of Orthodontics and Dentofacial Orthopaedics a force affecting such a change and recover its original Peoples Dental Academy, Bhopal, Madhya Pradesh, India form upon the removal of the force. 6Department of Periodontology and Implantology, Vyas Dental Elastic limit: The elastic limit is the maximum stress that College and Hospital, Jodhpur, Rajasthan, India a material can endure without undergoing permanent Corresponding Author: Sagar Mapare, Professor, Department deformation. of Orthodontics and Dentofacial Orthopaedics, Hedgewar Elastic modulus or modulus of elasticity: When a material is Dental College, Hingoli, Maharashtra, India. e-mail: Drmapare@ stressed it is usually found that the stress is proportional Rediffmail.Com to the strain, so their ratio is constant. In other words, International Journal of Preventive and Clinical Dental ResearcResearch,h, April-June (Suppl) 2018;5(2):2018;5(2):21-301-10 21 1 Mapare et al the material deforms linearly and elastically. This can be Chemical analysis shows that about 30–35% of latex represented by the expression consists of pure rubber, while water makes up another 60–65%. The remainder consists of small amounts of E = stress/strain. other materials such as resins, proteins, sugar, and Resilience: (stored or spring energy) Resilience represents mineral matter. Latex spoils easily and must therefore be the energy storage capacity of a wire. It is stressed not to processed into crude rubber as soon as possible after it exceed its proportional limit. has been tapped. This is done by separating the natural Plasticity: It is the property by which a material can rubber in the latex from water and other materials. About be molded into various forms and then hardened for 99% of all natural rubber comes from the latex of Hevea commercial use. brasiliensis. In laymen terms, we call it the rubber tree. Relaxation: It is defined as a decrease in force value carried In 1860, another Englishman, Greville Williams, heated or transmitted over time with the element maintained in some rubber and obtained a colorless liquid that he called a fixed activated state of constant strain. isoprene. Each isoprene molecule contains 5 carbon atoms Vulcanization: The process of heating sulfur–rubber and 8 hydrogen atoms (C5H8). The atom in the isoprene mixtures is known as vulcanization molecules always forms a definite pattern. Four of the carbon atoms form a chain. The fifth carbon atom branches 1,3 1 ounce (oz) = 28.35 gm. off from one of the carbons in the chain. Three hydrogen atoms surround the fifth carbon atom HISTORY OF ELASTICS AND ELASTOMERICS to form a methyl group. Elastomer is a general term that encompasses materials Natural rubber has many unsaturated carbon atoms. that, after substantial deformation, rapidly return to their Oxygen atoms from the air gradually attach themselves to these carbon atoms. This breaks down the rubber original dimensions. polymers so that the rubber becomes brittle or soft and Natural rubber was the first known elastomer, used by loses elasticity. The addition of antioxidants during the ancient Incan and Mayan civilizations. It had limited compounding prevents this action. use because of its unfavorable temperature behavior and Scientists have not discovered all the answers to the water absorption properties. chemistry of rubber. For example, they once believed that With the advent of vulcanization by Charles Goodyear sulfur atoms attached themselves to unsaturated carbon in 1839, uses for natural rubber greatly increased. Early atoms during vulcanization. But the sulfur reaction that advocates of using natural latex rubber in orthodontics makes rubber hard now seems more complicated than were Baker, Case, and Angle. this. In many other ways, the chemistry of natural rubber remains a mystery. Natural Rubber Synthetic Rubber When the early European explorers came to Central and South America, they saw the Indians playing with Synthetic rubber polymers developed from petrochemicals bouncing balls made of rubber. in the 1920s have a weak molecular attraction consisting The South American Indians called the rubber tree of primary and secondary bonds. cahuchu, i.e., weeping wood. The drops of latex oozing Elastomeric chains were introduced to the dental profes- from the bark made them think of big white tears. sion in the 1960s and have become an integral part of orth- odontic practice. They are used to generate light continuous In 1770, the English chemist Joseph Priestley discov- forces. They are inexpensive and relatively hygienic, can be ered that the materials could be used as an eraser to rub easily applied, and require no patient cooperation. out pencil marks. From this use we get the name rubber. There have been numerous advances in the manufac- A French man JMA Strange in 1841 claimed that he turing process, which have led to a significant importance used a rubber attached to some hooks on the appliance in their properties; with this there has been a greater surrounding the molars for retention. application of these elastics in clinics in a variety of uses. John Tomes in 1848 used the elastics springs with Rubber-like materials that are made from chemicals metal plates. were called synthetic rubbers because they were intended Celvin Case discussed the use of intermaxillary as substitutes for natural rubber. Chemists use the word elastics at the Columbia Dental Congress. However, in “elastomer” for any substance, including rubber, which 1893 Henry A Baker was credited with originating the use stretches easily to several times its length, and returns to of intermaxillary elastics with rubber bands and named it its original shape. Baker Anchorage. Angle in 1902 described the technique Manufacturers group synthetic rubbers into two at the New York Institute of Stomatology. classes: General-purpose and special-purpose. 2International Journal of Preventive and Clinical Dental Research, April-June (Suppl) 2018;5(2):21-30 22 IJPCDR Elastics and Elastomeric in Orthodontics Practice General-purpose Synthetic Rubbers Intraoral Elastics The most important general-purpose rubber is styrene- s #LASS)ELASTICSORHORIZONTALELASTICSORINTRAMAXILLARY butadiene rubber (SBR). It usually consists of about 3 parts elastics or intra-arch elastics (Fig.