Activator appliance

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Activator Appliance is an Orthodontics appliance that was developed by Viggo Andresen in 1908. This was one of the first functional appliances that was developed to correct functional jaw in the early 1900s. Activator appliance became the universal appliance that was used widely throughout Europe in the earlier part of the 20th century. [1]

Contents

History

Viggo Andersen first used this appliance on his daughter's mandibular teeth in the summer of 1908. He took the mechanical braces off from his daughter, and he had her wear the "Biofunctional Retainer" throughout the summer in the mandibular arch. The maxillary arch received Hawley retainer. After a while, Viggo realized that her daughter's occlusion remained the same. He then started using his retainer in his own private practice on his patients, and he saw similar results. Viggo, who was born in Denmark, moved to Norway in the 1920s. There he met Karl Haupl with whom Viggo devised the name "Activator" to describe his appliance. Haupl and Andersen worked closely together and published many textbooks pertaining to the Activator Appliance. The name Activator was first used in their first edition of textbook in the 1920s. Haupl believed that "Shaking of Bone Hypothesis" by Wilhelm Roux was the functional concept that described how the appliance would work. Their way of working with this appliance was named as the "Norwegian System". [2] The original activator was tooth-borne, passive appliance which was indicated to be loose-fitting.

Indications

Activator appliance was initially indicated in patient's who are growing. Therefore, young adolescents with growth potential showed the best results of this appliance. In addition, an adolescent or adult patient with retrognathic mandible, well aligned maxillary and mandibular dentition were also other indications of this appliance. Some of the malocclusions that can be treated with this appliance included Class II Division I, Class II Division II, Class III and Open Bites. [3]

Mode of Action

1st View - The mode of action for this appliance involved many different views throughout the existence of appliance. The initially theory consisted of Haupl-Andersen's ideas who believed that Isometric Muscular Contraction caused by Myotatic reflex activity was the primary way functional adaptation of the appliance took place. The functional adaptation led to a new way of mandibular closing pattern. This view was later supported by Alexandre Petrovic (1984) and McNamara (1973). Petrovic, in the 1970s, performed studies which found that Lateral pterygoid muscle played an important role on Mandibular condyle cartilage growth. [3] [4]

2nd View - This view was presented by Egil Peter Harvold (1974), Donald Woodside (1973) and Selmer-Olsen, Herren (1953). This view completely disregarded the Myotatic reflex as the basis to describe the functional adaptation. Proponents of this view believed that Viscoelastic Properties of Muscle and stretching of soft tissues was the primary way of functional adaptation. They believed in creating the construction bite opening which was beyond the postural rest position. They believed that the mandible would be engaged more if the bite is opened more. [4]

Components

Activator consists of acrylic components and wire components.

Acrylic

Activator appliance initially started out as one block of acrylic which fit in both maxillary and mandibular arch. The lower arch would see the horseshoe shaped lingual plate acrylic extending from distal of the last erupted molar. In the upper arch, initially the anterior portion is covered from canine to canine, but that was later modified, as seen with appliances such as Bionator Appliance which placed its emphasis on the tongue function.

Wire

The wire components of activator included a labial bow which was usually placed 1mm away from the front incisors and extended from canine to canine. The bow would be 0.9 - 0.8mm thick. Additional wire elements were later added to stabilize the appliance.

Construction Bite

The construction bite of Activator can consist of two types: Horizontal (H) Activator and Vertical (V) Activator.

H Activator

This type of construction bite involves significant changes in the sagittal or Anterio-Posterior dimension. Therefore, the mandible is brought forward by 6-7mm and it is opened 3-4mm. the vertical opening follows an individual's normal postural rest position.

V Activator

This type of construction bite involves significant changes in the vertical dimension. Thus mandible is only brought forward by 2-3mm but vertically the bite is opened by at least 7-8mm.

Types

Kinetor Activator (1951)

This type of activator was developed by Hugo Stockfish. This appliance had latex tubing between the upper and lower parts to stimulate function. This appliance was again modified for a longer usage for patients.

Bow Activator of A.M Schwarz (1956)

Schwarz modified the original activator appliance by making activator a two part appliance and connecting it with elastic bow. He said that the bow allows periodic adjustment of sagittal relationship of activator over time. This modification allowed transverse mobility, which was not present in previous modifications, and Schwarz believed that this provided additional stimulus for functional development. However, one of the disadvantages of this modification was that the appliance was easily distortable.

Herren's Activator (1953)

Herren modified the Activator appliance by including clasps on the appliance. He stated that the clasps allowed the activator to attach to the maxillary dentition, and thus make it more stable. He worried that slight movement of mandible during sleeping will allow the activator to fall out. He also extended the acrylic towards the floor of the mandible to restrict the movement of mandible. He believed in maximal sagittal advancement of the construction bite with 8-10mm vertical opening.

LSU or Shaye Activator

This type of activator was modification of the Herren's Activator. Robert Shage from LSU modified activator by having lower incisors bite on a plane formed by acrylic to impede the growth in occlusal direction. The occlusal acrylic on the posterior teeth was grounded away to assist in eruption of the molars, premolars. Therefore, he wanted to level the occlusal plane this way.

Elastic Open Activator of G. Klammt (1960)

This modification was developed by G. Klammt. This appliance was modified to include reduced acrylic for the purpose of patient compliance. The acrylic was replaced with wires which increase the flexibility of the appliance. This appliance resembled the Bionator Appliance.

Nite-Guide®/Occlus-o-Guide®/Ortho-T® Activators

Constructed from an elastomeric material, these original preformed activators are used in the primary to adult dentition but ideal for use in the early through late mixed dentition [5] [6] (these studies utilized Ortho-Tain's Nite-Guide® and/or Occlus-o-Guide®). Along with their activator properties, ideal for correction of class II malocclusion, being based on tooth size, these appliances aptly coined EGAs (Eruptive Guidance Appliances) also function as a positioner along with correcting overbite and mild to moderate crowding.

Harvold/Woodside Activator (1971)

Their modification included creating construction bite which allowed the bite to open around 10-15mm beyond the postural rest position of the mandible. They believed that viscoelastic properties of soft muscles and elasticity of soft tissues were predominating ways of how muscular adaptation and changes in form happened. Their sagittal opening remained around 3-5mm distal to the maximum protrusion of one's jaw.

Palate Free Activator (1974)

This modification was proposed by shaMohammed to combine the advantages of bionator and activator. The palatal area in this modification remains free of acrylic, making the appliance more convenient for patients and them being able to wear it for longer periods of time. The mandibular part of this appliance was same as the original mandibular part of activator, only the maxillary modification was added.

Propulsor (1980)

This modification had no wire connecting the upper and lower parts. Acrylic connected the upper and lower part with acrylic flanges. This type of activator was designed by Muhlemann and refined by Hotz. This appliance is sometimes known as the hybrid appliance because it has features of vestibular screen and monobloc.

U Bow Activator

This modification was made by Karwetzky. In this modification, the maxillary and mandibular active plates are joined at the 1st permanent molar region using a U-shaped bow. The bow is made up of 1 mm SS wire. The short leg is embedded in the upper plate and long leg is embedded in the lower plate.

Wunderer Activator

Wunderer made a modification of the activator to be used for the patients with Class III malocclusions. The appliance was split horizontally into an upper and lower part and a screw connect the two pieces of appliance. The occlusal surface of incisors in both arches are covered with acrylic. The screw used is named as Weise Screw. Turning the screw lead to the maxillary arch to move anteriorly and a back thrust of the mandible

Hamilton Expansion Activator

This type of activator was designed by Hamilton who used the expansion of an arch in this approach. The appliance has a screw in the middle for expansion. The activator is bonded to the maxillary arch and the forward guidance of the mandible can happen due to the lingual flanges of the appliance. This type of appliance is used in non-compliant patients.

Cybernator or Reduced Activator

The acrylic in this type of activator is reduced. However, the labial bow is retained in this type of activator. A feature of this appliance is Coffin Spring which is used in the maxillary arch which may help with expansion of the upper arch.

LM-Activator

This type of activator is particularly suitable for treatment in the early mixed dentition [7] [8] [9] [10] [11] [12] [13] but can also be used in other stages of dental development. In addition to guiding the mandible to a Class I relationship, it can also be used to align teeth and to correct crowding. The LM-Activator is made of silicone.

Headgear and Activator Therapy

Stockli-Teuscher Approach

In this type of approach, we can see that the inner bows are completely embedded in the labial side of the maxillary splint. The outer arms are bent upwards depending on the angle that is desired for the occlusal plane. [14] [15] [16] [17]

Hickam Approach

He placed the hooks on the labial bow to receive the J hook headgear. [18]

See also

Related Research Articles

<span class="mw-page-title-main">Orthodontics</span> Correctional branch of dentistry

Orthodontics is a dentistry specialty that addresses the diagnosis, prevention, management, and correction of mal-positioned teeth and jaws, as well as misaligned bite patterns. It may also address the modification of facial growth, known as dentofacial orthopedics.

<span class="mw-page-title-main">Malocclusion</span> Medical condition

In orthodontics, a malocclusion is a misalignment or incorrect relation between the teeth of the upper and lower dental arches when they approach each other as the jaws close. The English-language term dates from 1864; Edward Angle (1855-1930), the "father of modern orthodontics", popularised it. The word "malocclusion" derives from occlusion, and refers to the manner in which opposing teeth meet.

Orthodontic technology is a specialty of dental technology that is concerned with the design and fabrication of dental appliances for the treatment of malocclusions, which may be a result of tooth irregularity, disproportionate jaw relationships, or both.

Occlusion, in a dental context, means simply the contact between teeth. More technically, it is the relationship between the maxillary (upper) and mandibular (lower) teeth when they approach each other, as occurs during chewing or at rest.

<span class="mw-page-title-main">Overjet</span> Medical condition

Overjet is the extent of horizontal (anterior-posterior) overlap of the maxillary central incisors over the mandibular central incisors. In class II malocclusion the overjet is increased as the maxillary central incisors are protruded.

<span class="mw-page-title-main">Crossbite</span> Medical condition

Crossbite is a form of malocclusion where a tooth has a more buccal or lingual position than its corresponding antagonist tooth in the upper or lower dental arch. In other words, crossbite is a lateral misalignment of the dental arches.

Cephalometric analysis is the clinical application of cephalometry. It is analysis of the dental and skeletal relationships of a human skull. It is frequently used by dentists, orthodontists, and oral and maxillofacial surgeons as a treatment planning tool. Two of the more popular methods of analysis used in orthodontology are the Steiner analysis and the Downs analysis. There are other methods as well which are listed below.

<span class="mw-page-title-main">Jaw abnormality</span> Medical condition

A jaw abnormality is a disorder in the formation, shape and/or size of the jaw. In general abnormalities arise within the jaw when there is a disturbance or fault in the fusion of the mandibular processes. The mandible in particular has the most differential typical growth anomalies than any other bone in the human skeleton. This is due to variants in the complex symmetrical growth pattern which formulates the mandible.

Serial extraction is the planned extraction of certain deciduous teeth and specific permanent teeth in an orderly sequence and predetermined pattern to guide the erupting permanent teeth into a more favorable position.

Pre-eruption guidance is an orthodontic treatment method that allows for expansion of existing erupting teeth long before they appear in the mouth. The use off pre-eruption guidance appliances and the timing of extractions of certain deciduous teeth aligns the teeth naturally as opposed to orthodontic mechanical movement of permanent teeth into alignment after they have erupted. Research shows that pre-eruption guidance produces far more stable tooth alignment than alternative treatments.

A lip bumper is a dental appliance used in orthodontics, for various purposes to correct a dentition by preventing the pressure from the soft tissue. Lip bumpers are usually used in orthodontic treatment where the patient has a crowded maxillary or mandibular teeth in an arch.

Frankel appliance or Frankel Functional Regulator is an orthodontic functional appliance which was developed by Rolf Fränkel in 1950s for treatment to patients of all ages. This appliance primarily focused on the modulation of neuromuscular activity in order to produce changes in jaw and teeth. The appliance was opposite to the Bionator appliance and Activator appliance.

Molar distalization is a process in the field of Orthodontics which is used to move molar teeth, especially permanent first molars, distally (backwards) in an arch. This procedure is often used in treatment of patients who have Class 2 malocclusion. The cause is often the result of loss of E space in an arch due to early loss of primary molar teeth and mesial (forward) migration of the molar teeth. Sometimes molars are distalized to make space for other impacted teeth, such as premolars or canines, in the mouth.

Pendulum is an orthodontic appliance, developed by James J. Hilgers in 1992, that use forces to distalize the upper 1st molars to create space for eruption of impacted teeth or allowing correction of Class 2 malocclusion. This appliance is a fixed type of distalizing appliance that does not depend on the compliance of each patient to work. Hilgers published an article in Journal of Clinical Orthodontics in 1992 describing the appliance.

ACCO or Acrylic Cervical Occipital Anchorage is an appliance in field of orthodontics which is used for distalization of maxillary molars. This appliance is a removable type of appliance which was developed by Herbert I. Margolis. This appliance is intended to be worn 24 hours a day except during meals. It is one of the few removable appliances made for distalization of molars and thus require patient compliance for the treatment to be successful.

Intrusion is a movement in the field of orthodontics where a tooth is moved partially into the bone. Intrusion is done in orthodontics to correct an anterior deep bite or in some cases intrusion of the over-erupted posterior teeth with no opposing tooth. Intrusion can be done in many ways and consists of many different types. Intrusion, in orthodontic history, was initially defined as problematic in early 1900s and was known to cause periodontal effects such as root resorption and recession. However, in mid 1950s successful intrusion with light continuous forces was demonstrated. Charles J. Burstone defined intrusion to be "the apical movement of the geometric center of the root (centroid) in respect to the occlusal plane or plane based on the long axis of tooth".

Open bite is a type of orthodontic malocclusion which has been estimated to occur in 0.6% of the people in the United States. This type of malocclusion has no vertical overlap or contact between the anterior incisors. The term "open bite" was coined by Carevelli in 1842 as a distinct classification of malocclusion. Different authors have described the open bite in a variety of ways. Some authors have suggested that open bite often arises when overbite is less than the usual amount. Additionally, others have contended that open bite is identified by end-on incisal relationships. Lastly, some researchers have stated that a lack of incisal contact must be present to diagnose an open bite.

Orthodontic indices are one of the tools that are available for orthodontists to grade and assess malocclusion. Orthodontic indices can be useful for an epidemiologist to analyse prevalence and severity of malocclusion in any population.

The Herbst appliance is an orthodontic appliance used by orthodontists to correct class 2 retrognathic mandible in a growing patient. This is also called bitejumping. Herbst appliance parts include stainless steel surgical frameworks that are secured onto the teeth by bands or acrylic bites. These are connected by sets of telescoping mechanisms that apply gentle upward and backward force on the upper jaw, and forward force on the lower jaw. The original bite-jumping appliance was designed by Dr. Emil Herbst and reintroduced by Dr. Hans Pancherz using maxillary and mandibular first molars and first bicuspids. The bands were connected with heavy wire soldered to each band and carried a tube and piston assembly that allowed mandibular movement but permanently postured the mandible forward. The appliance not only corrected a dental Class II to a dental Class I but also offered a marked improvement of the classic Class II facial profile.

References

  1. ↑ Ahlin, Jeffrey H. (2003-12-01). Maxillofacial Orthopedics. Xulon Press. ISBN   9781591609407.
  2. ↑ Pancherz, Hans (1976-01-01). "Long-term effects of activator (Andresen appliance) treatment: a clinical, biometric, cephalometric roentgenographic and functional analysis". Odontologisk Revy. Supplement. Gleerup. 35: 1–70. ISBN   9789140042996. PMID   1068409.
  3. 1 2 Rakosi, Thomas; Graber, Thomas M.; Alexander, R. G. (2010-01-01). Orthodontic and Dentofacial Orthopedic Treatment. Thieme. ISBN   9783131277619.
  4. 1 2 Graber, Thomas M. (1997-01-01). Dentofacial Orthopedics with Functional Appliances. Mosby. ISBN   9780815135586.
  5. ↑ Keski-Nisula, K. (2008). "Orthodontic intervention in the early mixed dentition: a prospective, controlled study on the effects of the eruption guidance appliance". American Journal of Orthodontics and Dentofacial Orthopedics. 133 (2): 254–260. doi:10.1016/j.ajodo.2006.05.039. ISSN   0002-9416. PMID   18249292.
  6. ↑ Keski-Nisula, K. (2008). "Dentofacial changes after orthodontic intervention with eruption guidance appliance in the early mixed dentition". The Angle Orthodontist. 78 (2): 324–331. doi: 10.2319/012607-37.1 . ISSN   0003-3219. PMID   18251597.
  7. ↑ Keski-Nisula, K. (2008). "Orthodontic intervention in the early mixed dentition: a prospective, controlled study on the effects of the eruption guidance appliance". American Journal of Orthodontics and Dentofacial Orthopedics. 133 (2): 254–260. doi:10.1016/j.ajodo.2006.05.039. ISSN   0002-9416. PMID   18249292.
  8. ↑ Keski-Nisula, K. (2008). "Dentofacial changes after orthodontic intervention with eruption guidance appliance in the early mixed dentition". The Angle Orthodontist. 78 (2): 324–331. doi: 10.2319/012607-37.1 . ISSN   0003-3219. PMID   18251597.
  9. ↑ Myrlund, R. (2014). "One year treatment effects of the eruption guidance appliance in 7-to 8-year-old children: a randomized clinical trial". European Journal of Orthodontics. 37 (2): 128–134. doi: 10.1093/ejo/cju014 . ISSN   0141-5387. PMID   25005108.
  10. ↑ Keski-Nisula, Katri; Keski-Nisula, Leo; Varrela, Juha (2020-04-01). "Class II treatment in early mixed dentition with the eruption guidance appliance: effects and long-term stability". European Journal of Orthodontics. 42 (2): 151–156. doi:10.1093/ejo/cjz092. ISSN   0141-5387. PMID   31750513.
  11. ↑ Myrlund, Rita; Keski-Nisula, Katri; Kerosuo, Heidi (2018-11-20). "Stability of orthodontic treatment outcomes after 1-year treatment with the eruption guidance appliance in the early mixed dentition: A follow-up study". The Angle Orthodontist. 89 (2): 206–213. doi:10.2319/041018-269.1. ISSN   0003-3219. PMC   8120886 . PMID   30457353.
  12. ↑ Pellegrino, Marianna; Cuzzocrea, Maria Laura; Rao, Walter; Pellegrino, Gioacchino; Paduano, Sergio (2020-10-08). "Myofunctional Treatment of Anterior Crossbite in a Growing Patient". Case Reports in Dentistry. 2020: 1–8. doi: 10.1155/2020/8899184 . ISSN   2090-6447. PMC   7568144 . PMID   33101735.
  13. ↑ Ciftci, Volkan; Uzel, Aslıhan (December 2021). "Dento-skeletal effects of myofunctional appliance on patients with class II div 1 in mixed dentition stage: A cephalometric study". Pediatric Dental Journal. 31 (3): 235–241. doi:10.1016/j.pdj.2021.08.005. S2CID   244005272.
  14. ↑ Marşan, Gülnaz (2007-04-01). "Effects of activator and high-pull headgear combination therapy: skeletal, dentoalveolar, and soft tissue profile changes". The European Journal of Orthodontics. 29 (2): 140–148. doi: 10.1093/ejo/cjm003 . ISSN   0141-5387. PMID   17488997.
  15. ↑ Türkkahraman, Hakan; Sayın, M. Özgür (2006-02-01). "Effects of activator and activator headgear treatment: comparison with untreated Class II subjects". The European Journal of Orthodontics. 28 (1): 27–34. doi:10.1093/ejo/cji062. ISSN   0141-5387. PMID   16093256.
  16. ↑ Bondevik, Olav (1995-12-01). "Treatment needs following activator-headgear therapy". The Angle Orthodontist. 65 (6): 417–422. ISSN   0003-3219. PMID   8702067.
  17. ↑ Levin, R. I. (1985-02-01). "Activator headgear therapy". American Journal of Orthodontics. 87 (2): 91–109. doi:10.1016/0002-9416(85)90019-3. ISSN   0002-9416. PMID   3855608.
  18. ↑ "Stability of Class II, Division 1 Treatment with the Headgear-Activator Combination Followed by the Edgewise Appliance". www.arabmedmag.com. Retrieved 2016-10-18.
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