What is anchorage in orthodontics?
Anchorage in orthodontics is defined as a way of resisting movement of a tooth or number of teeth by using different techniques. Anchorage is an important consideration in the field of orthodontics as this is a concept that is used frequently when correcting malocclusions.
What is absolute absolute anchorage?
Absolute Anchorage. This type of anchorage is needed in a treatment when there is 0% movement of posterior teeth forward and 100% movement of anterior teeth backwards. This type of anchorage is usually produced by using mini-implants or temporary anchorage devices.
What is moderate anchorage in dentistry?
This type of anchorage is considered moderate, which involves 50% movement of both anterior and posterior teeth into the extraction space. The expectation in this type of anchorage is to see posterior teeth moving forward equally as compared to anterior teeth moving backwards.
What is the mechanism of tooth Anchorage?
As tooth movement creates reciprocal forces (Feldmann & Bondemark, 2006), anchorage can be obtained from teeth, mucosa, bone, implants or extra-orally (Roberts-Harry & Sandy, 2004).
What is anchorage orthodontic value?
Anchorage in orthodontics is defined as a way of resisting movement of a tooth or number of teeth by using different techniques. Anchorage is an important consideration in the field of orthodontics as this is a concept that is used frequently when correcting malocclusions.
What is reinforced anchorage in orthodontics?
The term anchorage in orthodontic treatment refers to methods of controlling unwanted tooth movement. This is provided either by anchor sites within the mouth, such as the teeth and the palate, or from outside the mouth (headgear).
What is reciprocal anchorage in orthodontics?
Reciprocal anchorage: The reciprocal anchorage refers to the resistance offered by two malposed units, when the dissipation of equal and opposite forces tends to move each unit towards a more normal occlusion.
Which device provides an absolute anchorage point during an orthodontic treatment?
A TAD is an implant that is fixed to bone for the purpose of providing an absolute anchorage point for movement of teeth. TADs are removed and discarded at the end of orthodontic treatment.
What is maximum anchorage?
Maximum anchorage refers to the situation where, strictly speaking, no such movement must occur if treatment goals are to be achieved. Anchorage can be quantified according to the amount of movement of the posterior teeth desired to close the residual extraction space.
Why is anchorage important in orthodontics?
Anchorage is an important consideration when planning orthodontic tooth movement. Unwanted tooth movement known as loss of anchorage can have a detrimental effect on the treatment outcome. Anchorage can be sourced from the teeth, the oral mucosa and underlying bone, implants and extra orally.
What is intra oral anchorage?
Intra-Oral Intra-maxillary Inter-maxillary Intra-maxillary Anchorage: is obtained from teeth in one jaw to move other teeth in same jaw. Inter-maxillary Anchorage: is obtained from teeth in one jaw to move other teeth in opposite jaw.
What is Baker anchorage?
ANCHORAGE. Anchorage in which the resistance units situated in one jaw are used to effect tooth movement in the other jaw. It is also termed BAKER'S ANCHORAGE.
What is loss of anchorage?
Anchorage loss (AL) is a potential side effect of orthodontic mechanotherapy. In the present study, it is defined as the amount of mesial movement of the upper first permanent molar during premolar extraction space closure.
What is an anchorage retainer?
Whenever our teeth need an extra push to shift them into a straighter position, orthodontists will typically install a temporary anchorage device, commonly known as a “TAD.” Although they're not used in every case, they help pull, push, and lift difficult to adjust teeth into the correct position.
How is anchorage calculated in orthodontics?
The amount of force on each anchor tooth in simple anchorage is equal to the total moving force component of the appliance divided by the number of anchored teeth.
What appliance takes anchorage muscle?
This mandibular space regainer utilizes a labial lip bumper that inserts through buccal tubes on the molar bands. Lip pressure creates a distal force that moves the molars posteriorly.
What is orthodontic anchorage?
Anchorage in orthodontics means to prevent ‘an unwanted tooth movement.’ Anchorage is the resistance to the force that is not wanted to minimize the side effects on other teeth while aligning tooth or teeth in orthodontic treatment.
What are the types of anchorage?
Orthodontists need a stable and not a fragile anchor to do the orthodontic treatment without any damages to other oral structures like teeth and gums. So, they try to use the most suitable anchorage type in or outside of your mouth.
What are temporary anchorage devices (TADs)?
Temporary anchorage devices or TADs are anchorage tools that are mechanically fixed into the bone in the mouth to act as anchor for your orthodontic appliance. TADs can be removed when your orthodontic treatment is over or when it is not necessary anymore.
Important tips on orthodontics anchorage
Finally, it is a good idea to follow these tips to have much stable anchorage for your orthodontic treatment
Why is reinforced anchorage needed?
Reinforced anchorage is required for the differential movement of one tooth over another, for example when retracting the anterior teeth into a premolar space.
What can be gained from lip bumpers?
Oral mucosa and bone. Soft tissue anchorage can be gained from lip bumpers to reduce mesial movement of lower molars. The palatal vault can also supplement anchorage to prevent mesialisation of posterior teeth by using a Nance button, which is effective in high vaulted palates (Naish et al., 2015).
What is the difference between simple and compound anchorage?
Simple anchorage pits one tooth against another, whereas compound anchorage utilises more than one tooth in the anchor block to produce differential movement in favour of the less supported section. This is shown in Figure 3 and 4.
What is anchorage in orthodontics?
Anchorage is defined as the resistance to unwanted movement in line with Newton’s 3 rd Law which states every action has an equal and opposite reaction (Proffit, Fields, & Sarver, 2013; Roberts-Harry & Sandy, 2004). Teeth can absorb and prevent shock and trauma and resist displacement, but are not absolute rigid fixation (Strang, 1941). It is for this reason that anchorage considerations in Orthodontics are ever important.
Why are premolars extracted?
Premolars are most commonly extracted due to their position within the arch; close to anterior crowding, the posterior section can be used as an anchorage unit. Extraction of first premolar will reinforce posterior sections, often used if anterior teeth are to be retracted.
What bone provides resistance to tooth movement?
Cortical bone provides resistance to tooth movement; it is observed that roots pushed against the cortical plate increase the anchorage value of the teeth, and that this is increased in mandibular over maxillary teeth due to the density of the bone (Hixon, 1970).
How does headgear work?
Headgear achieves anchorage from the cranial vault. It connects to the intraoral appliance via facebow and is worn around 12 hours per day. Primarily used for distalisation of molars, the direction of pull on the extraoral device alters the vertical component, as seen in Figure 5 (Naish et al., 2015). Cervical headgear can extrude and distally tip upper molars due to the direction of force. This can be reduced by using occipital or high pull headgear, which does not exert as high a force. Reverse headgear is effective for mesial movement of teeth in class 3 cases (Roberts-Harry & Sandy, 2004). Their use is declining due to more prominent use of implants for anchorage, issues with compliance and safety concerns with regard to ocular injuries (Naish et al., 2015).
Overview
Classification based on space closure
Ravindra Nanda and Charles J. Burstone described three types of anchorages that are based on the need during a treatment where space closure is needed. In some orthodontic cases, teeth have to be removed in order to either relieve dental crowding or reduce a large overjet or overbite. Therefore, the space created after removing teeth is usually closed during an orthodontic treatment. A space can be closed by either moving back teeth forward or front teeth backward.
History
One of the earliest uses of anchorage came from Henry Albert Baker for his use of the intermaxillary anchorage or Baker's Anchorage. This type of anchorage involves using elastics from one jaw to the other, in the form of either Class 2 elastics (moving upper teeth back) where lower molar teeth serve as anchors, or Class 3 elastics (moving lower teeth back) where upper molars serve as anchors. Intramaxillary anchorage is also used in the form of E-chain, when elas…
Classification based on site
• Intraoral – This type of anchorage is established within the mouth. This involves primary and compound anchorage.
• Extraoral – This type of anchorage is established outside the mouth. This involves using headgear or face masks. One of the disadvantages of using extraoral anchorage is that the anchorage is away from the site of the tooth movement. In addition, in wearing orthodontic headgear, the compliance of patients is usually lower with adolescent patients, …
• Intraoral – This type of anchorage is established within the mouth. This involves primary and compound anchorage.
• Extraoral – This type of anchorage is established outside the mouth. This involves using headgear or face masks. One of the disadvantages of using extraoral anchorage is that the anchorage is away from the site of the tooth movement. In addition, in wearing orthodontic headgear, the compliance of patients is usually lower with adolescent patients, alth…
Classification based on number of teeth
Robert Moyers defined the classification of anchorage in the number of units.
• Simple/primary – Anchorage using one tooth
• Compound – Anchorage using two or more teeth
• Reinforced – Anchorage that uses additional teeth or any other appliances to reinforce the primary anchorage. This can involve extraoral or muscular anchorage. A reinforced anchorage based on appliances can use
Classification based on implant
Orthodontic mini-implants can be used for the purpose of anchorage in an orthodontic treatment. The implants can be used to provide either direct or indirect anchorage.
In this type of setup, orthodontic force is applied directly from the implant to one or multiple teeth. In this type of anchorage, the location of the implant plays a very important role due to different force vectors being affected.
Classification based on bone
Cortical bone is known to resorb slower than the medullary bone. Therefore, cortical anchorage is used in orthodontics to allow for slower movement of teeth, especially molars in the posterior dentition. A clinician may produce a movement which allows the buccal roots of the permanent molars to move buccally (outside), eventually contacting the cortical bone. It is claimed that by using cortical bone against posterior teeth, mesial movement of posterior teeth can be prevente…