orthodontic Invisalign
In recent years, increasing numbers of adult patients have sought orthodontic treatment and expressed a desire for esthetic and comfortable alternatives to conventional fixed appliances.
The figure of teenager patients looking for orthodontic treatment has increased, so the aesthetics of the orthodontic appliance has become a topic of interest. The orthodontic patient today demands a beautiful smile at the end of treatment, but is equally concerned with appearance during the treatment.
Clear aligners are the new age Aesthetic Orthodontic treatment .The demand of invisalign is increasing now a days due to its esthetic demand for those patients who are indisposed of wearing usual orthodontic appliances. Invisaligners are thin transparent removable unobserved plastic aligners for successful moving of teeth into their required position.
What is the Invisalign Appliance?
The Invisalignis made up of a transparent, thin plastic material formed with CAD-CAM laboratory techniques to gradually guide the teeth into proper alignment. As a technique, it has been commercially available for a decade.The aligners are analogous to the splints that cover the clinical crowns as well as the marginal gingiva. Each aligner is planned to move the teeth a maximum of about 0.25 to 0.3 mm over a 2-week period. Excellent observance is mandatory as the appliance has to be worn a minimum of 20 to 22 hours a day and each aligner should be worn 400 hours to be effective.
A Brief History of ClearAligner Treatment
Clear aligner treatment is not new. Clear aligner treatment falls into two basic categories. The first category consists of those thermoformed appliances, sometimes known as Essix Retainers (Raintree Essix, Dentsply Corp., York, PA), that are fabricated by making adjustments to the tooth positions on plaster or stone models and fabricating one or more aligners to correct a minor malocclusion.A Brief History of ClearAligner Treatment
These types of appliances are oftentimes fabricated in the orthodontist’s office or sometimes sent out to commercial laboratories to be made under a trademarked name such as Simpli 5 (Simpli 5 Express Aligner System, Ormco Corp., Orange, CA). These types of in-office prepared aligner systems have been in use since around 1994.The second category is Invisalign (Align Technology, Inc., Santa Clara, CA). Invisalign is an exclusive orthodontic technique that uses a series of computer generated custom plastic aligners to gradually guide the teeth into proper alignment.
Invisalign is both a brand name and a technique and is used synonymously.
Invisalign is the only computer-aided design and manufacturing (CAD-CAM) precision aligner product available in the United States.
As a technique, Invisalign has now been commercially available to orthodontists since 1998. The company and the technique was the brainchild of two graduate business students at Stanford University in 1997, Kelsey Wirth and Zia Chishti. As the story goes, both were given Essix retainers to correct some minor orthodontic relapse and were struck by the same question:
“Why couldn’t I have had these instead of braces?”
Their orthodontists both told them that it was only for very minor problems and dismissed the possibility of correcting complex malocclusions with aligners as nonsense.
Imaginative with any “baggage” of an orthodontic background, they formed a company (Align Technology, Inc.) to attempt to use CAD-CAM to mass produce aligners that would be capable of treating a broader range of malocclusions.
They were fortunate in attracting the interest of Robert Boyd, chairman of the Department of Orthodontics, University of the Pacific.
He assisted in this attempt by being a consultant, and in doing so he and his residents provided a means to test this new technology.
The concept on which the Invisalign system is asked has been around since the 1940s. In 1945, H.D.Kesling suggested that a series of tooth positioners be used to produce the types of movements that are needed for orthodontic treatment. Some years later, Nahoum described a method to change tooth contours using thermoformed plastic. In 1971, Pontiz introduced a thermoformed plastic appliance called the “invisible retainer” made on a master model that prepositioned teeth with base-plate wax. He claimed that this appliance could produce limited tooth movement.
McNamara and others also described using invisible retainers to achieve minor tooth movement. Sheridan and others later developed a technique involving interproximal tooth reduction and progressive alignment using clear Essix appliances, and those techniques were further developed by Hilliard and Sheridan with a series of special thermoforming pliers designed to enhance specific movements.
Although these techniques based on Kesling’s proposal of using removable appliances have been used to some degree in the past, the laboratory construction has always been tedious and had previously limited the widespread adoption of removable aligner techniques.
The removable orthodontic aligner technique has now become a contemporary treatment alternative that orthodontists may offer their patients since Align Technology, Inc. developed the combined computer technology and custom manufacturing processes.
Such aligner is worn for approximately 20 hours per day and is changed approximately every two weeks.
each aligner will move the teeth around 0.25 to 0.3 mm.
INDICATIONS FOR INVISALIGN APPLIANCES
• Mild crowded and malalingned problems (1-5 mm)• Spacing problems (1-5 mm)
• Deep overbite (Class II div 2 cases )
• Narrow arches that can be expanded without tipping the teeth too much.
• Absolute intrusion (1 or 2 teeth)
• Lower incisor extraction for severe crowding cases.
• Tip molar distally
ADVANTAGES5
• The trays are clear, aesthetic, comfortable – no metal brackets or wires to cause mouth irritation or lacerations.• Clear aligners are often not visible, allowing patients to smile with greater confidence
• Better oral hygiene than fixed. Unlike traditional braces, the trays can be removed for brushing, flossing, and eating.
• Shorter dental appointments.
• Retention facilitated.
• Ideal for retreatment.
• Decreased occlusal abrasion from parafunctional habits during treatment.
• Disarticulation of the teeth may be advantageous for patients with TMJ problems.
• Technically much easier than lingual appliances.• Approximating the treatment duration a little more precisely than braces
• Avoiding extractions of premolars by creating interdental space via interproximal reduction
• Less frequent trips to the dental chair by allowing the patients to replace their aligners on their own every few weeks
• Healthier periodontal tissue and less risk of enamel decalcification by avoiding brackets
The Invisalign system also boasts improved hygiene over traditional braces. Because the clear retainers are removable, patients can brush and floss as they normally would, reducing the chances of possible staining and decay that often occurs with traditional braces.
Food and drink choices are less restrictive, as well. If patients wish to eat sticky candy or drink soda, they may do so after removing their clear Invisalign retainer.
DISADVANTAGES
removable in nature.patient motivation required.
it should be worn 22 hrs/ day.
Devices should be removed during meals.
poor patient compliance
missed appointments, deprived oral hygiene and excessive bone enlargement lengthen treatment time and affect quality results.
increase in price.
Intermaxillary Appliances
The removable clear Invisalign appliance around the teeth decreases the use of interarch mechanics (e.g., Class II and Class III elastics). Some practioners are using elastics on buttons bonded to the buccal surfaces as adjuncts to tooth movement.
Treatment Time
The treatment duration is prolonged as the treatment plan must include the chronological movements for every tooth from starting to end of the treatment.If changes are required once the treatment starts, significant additional span and documentation are required to alter the treatment plan. In addition, the lag time between formulating a treatment plan and inserting the appliance can be up to 2 months.
CLINICAL METHOD
Pretreatment study models are prepared.In addition, it is important to prepare high precision impressions by using polyvinyl material.
The bite is also recorded, and the impressions are sent to the Invisalign office.
Highly sophisticated softwares are used, which through a 3D scan technology create a virtual patient. Other specific softwares include ‘Tooth shaper’ & ‘Autobite tool’ which identify the shape of the teeth and occlude them in centric relation.
With the help of other software like ClinCheck set-up, diagnosis and treatment planning is done which is also used to evaluate the need for (interproximal reduction) IPR, extraction, expansion, distalization and proclination. It also show treatment limits to patient as it evaluates the anchorage with superimposition or surgical simulation tools.
Aligners other than Invisalign are USFDA approved:
Clear path aligners,Inman aligners,
Nuvola And Fantasmino System.
Fantasmino® aligners are made of poly-vinyl chloride (PVC), a material with elastic characteristics following a plastic deformation when exposed to moderate loads. This characteristic allows reducing the optimal wear time to 14 h per day: the deformations passive by the aligner when worn generate a force that is transferred to the teeth. The thickness of the PVC aligners varies with the desired type of tooth movement but never exceeds 1 mm.
Nuvola® aligners are made of polyethylene terephthalate glycol (PETG), a light, resistant, and
very clear material. It is resistant to time and wear,
and its elasticity allows for a gradual tooth movement. PETG aligners have a thickness that changes throughout the different treatment phases:
0.75 mm at the beginning of treatment, 0.85 mm during the intermediate phase, and 1 mm at the end
of treatment. This system requires an optimal wear time of 22 h.