IN THE NAME OF GOD

Dr:Nahvi

Force eruption

Force eruption

• Unerupted tooth

• Fractured tooth

Tooth eruption 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 elasticityMaintains 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 appliancesRemovable appliances

• Fixed appliancesDo not require special patient cooperation precise coronal and root movements

• Removable appliancesless chairtimebetter oral hygieneMore 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

• 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 resorption2) External cervical resorption3) Dentoalveolar ankylosis4) Calcific metamorphosis of the pulp and aseptic pulp necrosis.

Dental Press J Orthod. 2010 Nov-Dec;15(6):18-24

Thank You