IN THE NAME OF GOD Force eruption Dr:Nahvi

Force eruption Unerupted tooth Fractured tooth

Tooth eruption Eruption delayed : A permanent tooth should erupt: 6 months after natural exfoliation of its predecessor Eruption delayed : if the interval extends to more than 1 year.

Eruption of a tooth is considered to be delayed : The normal time for eruption has been exceeded. The tooth is not present in the dental arch and shows no potential for eruption. The root of the unerupted tooth is completely formed. The homologous tooth has been erupted for at least 6 months. J Can Dent Assoc 2010

Most commonly become impacted third molars maxillary canines maxillary central incisors mandibular second premolars

Causes of Delayed Eruption Localized Generalized

Localized the presence of supernumerary teeth(most common ) Odontoma dilaceration malpositioning of the tooth germ Crowding calcifying odontogenic cyst trauma to the corresponding deciduous tooth

systemic conditions cleidocranial dysostosis hypothyroidism Gardner syndrome Down syndrome

Criteria for Treatment chief complaint At least 3 mm of bone The tooth is mature J Can Dent Assoc 2010;76:a147

Alignment of an impacted tooth position and direction degree of root completion degree of dilacerations presence of space

Treatment planning: 1-surgical exposure 2-Attachment to the tooth 3-Orthodontic mechanics

surgical exposure (1) exposure of the entire labial aspect (the window approach) (2) a technique which exposes only 4–5 mm of the labial aspect

Attachment Gold chain Band Cast gold crown,onlay Threated pin Wire loop Direct bond attachment(the best)

General characteristics of orthodontic Forces Optimal:light,continuous -Ideal material Maintains elasticity Maintains force over a range of tooth movement

Force Continuous Interrupted Intermittent Extrusion 35-60gr

Continuous

Interrupted

Intermittent

Contemporary orthodontics

Direction of force parallel to the long axis avoid torquing forces Oral Maxillofacial Surg Clin N Am 16 (2004) 75-89

Force eruption Fixed appliances Removable appliances

Fixed appliances Removable appliances Do not require special patient cooperation precise coronal and root movements Removable appliances less chairtime better oral hygiene More esthetic

Removable appliances retention clasps labial bow Hook(for attachment of elastics) Finger spring,Zspring,Canine retractor

Removable appliances at least 10 hours per day. Rest intervals,not to exceed five hours per day. wear the appliance 24 hours a day, removing it only for meals

the elastics should be changed every two or three days. Lingual tipping will be minimized when the labial bow is used for the extrusive force JCO/JULY 2002

Fixed appliances coil : maintains the space anchorage and balancing resistance J Can Dent Assoc 2010

two teeth on either side of a multi-rooted tooth (4 anchors) Anchorage support for the extrusion—a minimum of one tooth on either side of a single-rooted tooth (2 anchors) or two teeth on either side of a multi-rooted tooth (4 anchors) Use a heavy square or rectangular NiTi wire to minimize tipping

J Can Dent Assoc 2010;76:a147

Magnetic force For a patient with other missing teeth Contemporary orthodontics

Elastics -light -medium(1/8 =3.18mm 127.58gr) -heavy Orthodontic Elastics (3/8", 5/16", 1/4", 3/16", 1/8") Shiraz Univ Dent J 2009; 10(1):7-15

clinical problems (canine) 1) Lateral root resorption 2) External cervical resorption 3) Dentoalveolar ankylosis 4) Calcific metamorphosis of the pulp and aseptic pulp necrosis. Dental Press J Orthod. 2010 Nov-Dec;15(6):18-24