Elastics (orthodontics)

Elastics are rubber bands used in the field of orthodontics frequently to correct different type of malocclusions. The elastic wear is prescribed by an orthodontist or a dentist in an orthodontic treatment. The longevity of the elastic wear may vary from anywhere from two weeks to several months. The elastic wear can go anywhere from 12 hours to 23 hours a day, wearing either during the night or throughout the day depending on the requirements for each malocclusion. There are many different types of elastics which may produce different forces on teeth. Therefore, using elastics with specific forces is critical in achieving an good orthodontic occlusion.[1]

The term intermaxillary elastics is used when elastics can go from maxillary to mandibular arch. Intra-maxillary elastics are elastics used in one arch only, either mandibular or maxillary. People using elastics for orthodontic correction change their elastics 3–4 times during the day. Elastic wear is recommend to be used in a rectangular wire to minimize side effects. Elastic wear depends on the compliance of the patient. A non-compliant patient should never be instructed to continue wearing elastics. Other options may be considered for the non-compliant patients.[2]

History

Natural rubber used by the Incan civilization and Maya civilization was the first known elastomeric to be used. Charles Goodyear developed the process of Vulcanization[3] after which the used of natural rubber increased. Henry Albert Baker is known to be the first person who was known to use elastics to correct position of teeth in the late 1800s. He eventually coined the elastic wear a term known as Baker Anchorage. However, some people have debated that Calvin Case was the first to use the intermaxillary elastics, which included the father of orthodontics Edward Angle.

The natural rubber is known to absorb water and deteriorate its elasticity fairly quickly. Therefore, Latex elastics became prominent in usage in orthodontics in the early 1900s. Later Synthetic elastics developed in 1960s superseded all other type of elastics for use in orthodontic correction of teeth.

Elastic forces

Elastics are available in many different type of forces. Following is the list of forces that can be found in different elastics. The forces and the labeling of the forces may depend on different manufacture and type of elastics. These forces are pertaining to intermaxillary elastics.

Force Rating Force (oz.) Force (g)
Light 2 oz. 56.7 g
Medium-Light 3 1/2 oz. 99.2 g
Medium 4 oz. 113.4 g
Medium-Heavy 5 1/2 oz. 155.9 g
Heavy 6 oz. 170.1 g
Extra Heavy 8 oz. 226.8 g

Class II elastics

Class 2 elastics are used from lower 1st molar to upper canine tooth. They can be used for many different reasons, such as Class 2 malocclusions, to reinforce anchorage in a case where an extraction has been done, to allow the maxillary incisors to move backwards, and to correct midline deviation and allow buccal movement of lower incisors which are tipped backwards. It is very important to know the side effects of Class II elastics before using them in an orthodontic treatment. The following are the effects of Class 2 elastics:[4][5]

Effect on Class II Malocclusion

A systematic review done by Janson et al.[6] in 2013 looked at effect of Class 2 elastics in correction the class II malocclusions in 11 studies. The authors concluded that Class II elastics are effective in correcting Class II malocclusions, and their effects are primarily dento-alveolar. Their side-effects primarily included flaring of mandibular incisors, loss of Mandibular anchorage (molars moving forward and worsening of smile esthetics due to extrusion of upper incisors.

Class III elastics

Class 3 elastics are used in an orthodontic case when the molar relationship is close to Class 1 malocclusion. It is important to understand that Class 3 malocclusions due to skeletal discrepancy (mandibular prognathism) cannot be corrected with Class 3 elastics.[7] It is important to evaluate soft tissue and hard tissue esthetics of a patient before attempting to use Class 3 elastics. Elastic wear will only produce changes in dentition, with no documented changes produced in soft and hard tissue. The following are the side-effects of Class 3 elastics:[8]

See also

References

  1. ↑ Nolting, Paul R. (1937-08-01). "Intermaxillary elastics". International Journal of Orthodontia and Oral Surgery. 23 (8): 812–813. doi:10.1016/S1072-3498(37)80050-3.
  2. ↑ Stewart, C. M.; Chaconas, S. J.; Caputo, A. A. (1978-04-01). "Effects of intermaxillary elastic traction on orthodontic tooth movement". Journal of Oral Rehabilitation. 5 (2): 159–166. ISSN 0305-182X. PMID 280630.
  3. ↑ "Charles Goodyear | Goodyear Corporate". corporate.goodyear.com. Retrieved 2016-09-03.
  4. ↑ "Timisoara Medical Journal -The Effect of Intermaxillary Elastics in Orthodontic Therapy". www.tmj.ro. Retrieved 2016-09-03.
  5. ↑ Janson, Guilherme; Sathler, Renata; Fernandes, Thais Maria Freire; Branco, Nuria Cabral Castello; Freitas, Marcos Roberto de (2013-03-01). "Correction of Class II malocclusion with Class II elastics: a systematic review". American Journal of Orthodontics and Dentofacial Orthopedics: Official Publication of the American Association of Orthodontists, Its Constituent Societies, and the American Board of Orthodontics. 143 (3): 383–392. doi:10.1016/j.ajodo.2012.10.015. ISSN 1097-6752. PMID 23452973.
  6. ↑ Janson, Guilherme; Sathler, Renata; Fernandes, Thais Maria Freire; Branco, Nuria Cabral Castello; de Freitas, Marcos Roberto (2013-03-01). "Correction of Class II malocclusion with Class II elastics: A systematic review". American Journal of Orthodontics and Dentofacial Orthopedics. 143 (3): 383–392. doi:10.1016/j.ajodo.2012.10.015.
  7. ↑ Janson, Guilherme; de Freitas, Marcos Roberto; Araki, Janine; Franco, Eduardo Jacomino; Barros, Sérgio Estelita Cavalcante (2010-08-01). "Class III subdivision malocclusion corrected with asymmetric intermaxillary elastics". American Journal of Orthodontics and Dentofacial Orthopedics: Official Publication of the American Association of Orthodontists, Its Constituent Societies, and the American Board of Orthodontics. 138 (2): 221–230. doi:10.1016/j.ajodo.2008.08.036. ISSN 1097-6752. PMID 20691365.
  8. ↑ Zimmer, Bernd; Nischwitz, Diana (2012-09-01). "Therapeutic changes in the occlusal plane inclination using intermaxillary elastics". Journal of Orofacial Orthopedics = Fortschritte Der Kieferorthopädie: Organ/Official Journal Deutsche Gesellschaft Für Kieferorthopädie. 73 (5): 377–386. doi:10.1007/s00056-012-0100-5. ISSN 1615-6714. PMID 22955576.
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