Tuesday, October 24, 2017

Arch Length Changes from 6 Weeks to 45 Years


Resident’s Name:            Carol Caudill                                                                        Date: 10/18/2017
Article Title: Arch Length Changes from 6 Weeks to 45 Years
Author(s): Samir Bishara, Jane Jakobsen, Jean Treder, Arthur Nowak
Journal: The Angle Orthodontist
Date: 1998
Major Topic: arch length
Type of Article: longitudinal study
Main Purpose: To look at the changes in maxillary and mandibular total arch length on a longitudinal basis over a 45 year period
Key Points: (2 lines Max): Arch length increases until 13 in the maxillary arch and 8 in the mandibular arch. Then consistent decreases occur in both arches mesial to the permanent first molars.

·      While many studies have looked at changes in dental arch in children, few have studied changes in adults. These changes are important to predict stability of treatment results.

Materials and Methods
·      28 females and 33 male infants were evaluated at 6 weeks, 1 year, and 2 years
·      15 males and 15 females were evaluated at 3, 5, 8, 13, 26, and 45 years

Results
·      Males have significantly greater total arch length in both arches than females.
·      From 6 weeks to 2 years both arches increased significantly in males and females.
·      From 3 to 13 years maxillary arch length increased significantly.
·      From 3 to 8 mandibular arch length increased significantly.
·      From 8 to 13 years the mandibular arch length started to decrease significantly.
·      Between 13 and 45 years, both the maxillary and mandibular arches decreased significantly.

Maxillary arch length changes
Age
Males
Females
6 weeks - 2 years
15.1 mm increase
16.4 mm increase
3 – 13 years
4.0 mm increase
2.4 mm increase
13 – 45 years
5.7 mm decrease
4.6 mm decrease

Mandibular arch length changes
Age
Males
Females
6 weeks - 2 years
14.2 mm increase
14.0 mm increase
3 – 8 years
1.9 mm increase
2.0 mm increase
8 – 45 years
7.4 mm decrease
8.3 mm decrease

Discussion
·      The greatest change in arch length occurs during the first 2 years of life
·      After age 13 in the maxilla and 8 in the mandible, arch length continues to decrease through age 45

Remarks:
1-
2-
Assessment of Article:  Level of Evidence/Comments: Level II

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