(viii) Attachments may be bonded to one or more teeth during the course of treatment to facilitate tooth movement and/or appliance retention. These will be removed after treatment is completed;
(ix) Attachments may fall off and require replacement.
(x) Teeth may require interproximal recontouring or slenderizing in order to create space needed for dental alignment to occur;
(xi) The bite may change throughout the course of treatment and may result in temporary patient discomfort.
(xii) In rare instances, slight superficial wear of the aligner may occur where patients may be grinding their teeth or where the teeth may be rubbing and is generally not a problem as overall aligner integrity and strength remain intact.
(xiii) At the end of orthodontic treatment, the bite may require adjustment (“occlusal adjustment”).
(xiv) Atypically-shaped, erupting, and/or missing teeth may affect aligner adaptation and may affect the ability to achieve the desired results.
(xv) Treatment of severe open bite, severe overjet, mixed dentition, and/or skeletally narrow jaw may require supplemental treatment in addition to aligner treatment.
(xvi) Supplemental orthodontic treatment, including the use of bonded buttons, orthodontic elastics, auxiliary appliances/ dental devices (e.g. temporary anchorage devices, sectional fixed appliances), and/or restorative dental procedures may be needed for more complicated treatment plans where aligners alone may not be adequate to achieve the desired outcome.
(xvii) Teeth which have been overlapped for long periods of time may be missing the gingival tissue below the interproximal contact once the teeth are aligned, leading to the appearance of a “black triangle” space.
(xviii) Aligners are not effective in the movement of dental implants.
(xix) General medical conditions and use of medications can affect orthodontic treatment;
(xx) Health of the bone and gums which support the teeth may be impaired or aggravated;
(xxi) Oral surgery may be necessary to correct crowding or severe jaw imbalances that are present prior to wearing the Invisalign product. If oral surgery is required, risks associated with anesthesia and proper healing must be taken into account prior to treatment;
(xxii) A tooth that has been previously traumatized, or significantly restored may be aggravated. In rare instances the useful life of the tooth may be reduced, the tooth may require additional dental treatment such as endodontic and/or additional restorative work and the tooth may be lost;
(xxiii) Existing dental restorations (e.g. crowns) may become dislodged and require re-cementation or in some instances, replacement;
(xxiv) Short clinical crowns can pose appliance retention issues and inhibit tooth movement;
(xxv) The length of the roots of the teeth may be shortened during orthodontic treatment and may become a threat to the useful life of teeth;
(xxvi) Product breakage is more likely in patients with severe crowding and/or multiple missing teeth;
(xxvii) Orthodontic appliances or parts thereof may be accidentally swallowed or aspirated;
(xxviii) In rare instances, problems may also occur in the jaw joint, causing joint pain, headaches or ear problems;
(xxix) Allergic reactions may occur; and
(xxx) Teeth that are not at least partially covered by the aligner may undergo supraeruption;
(xxxi) In rare instances patients with hereditary angioedema (HAE), a genetic disorder, may experience rapid local swelling of subcutaneous tissues including the larynx. HAE may be triggered by mild stimuli including dental procedures.