ABSTRACT

Objective:

To evaluate the effectiveness of computer-assisted orthodontic treatment technology to produce the tooth position prescribed by the virtual treatment plan.

Materials and Methods:

Posttreatment models of 23 patients treated with SureSmile were digitally superimposed on their corresponding virtual treatment plan models utilizing best-fit surface-based registration. Individual tooth-position discrepancies between virtual treatment plan and actual outcome were computed. Discrepancies less than 0.5 mm in mesial-distal, facial-lingual, and vertical dimensions, and less than 2° for crown torque, tip, and rotation were considered clinically ideal. One-sided test of equivalence was performed on each discrepancy measurement, with P < .05 considered statistically significant.

Results:

Mesial-distal tooth position was clinically ideal for all teeth with the exception of maxillary lateral incisors and second molars. Facial-lingual tooth position was clinically ideal for all teeth except maxillary central incisors, premolars, and molars, and mandibular incisors and second molars. Vertical tooth position was clinically ideal for all teeth except mandibular second molars. For crown torque, tip, and rotation, discrepancy exceeded the limits considered clinically ideal for all teeth except for crown torque on mandibular second premolars and crown tip on mandibular second premolars and first molars.

Conclusions:

The effectiveness of computer-assisted orthodontic treatment technology to achieve predicted tooth position varies with tooth type and dimension of movement.

ABSTRACT

Objective:

To describe maxillary growth and maturation during infancy and early childhood.

Materials and Methods:

Serial cephalograms (N = 210) of 30 subjects (15 females and 15 males) from the Bolton-Brush Growth Study were analyzed. Each subject had a series of six consecutive cephalograms taken between birth and 5 years of age, as well as one adult cephalogram. Twelve maxillary measurements (eight linear and four angular) and seven landmarks were used to characterize maxillary growth. Maturation of the linear measures was described as a percentage of adult status.

Results:

Maxillary and anterior cranial base size increased in both sexes between 0.4 and 5 years of age. The linear anteroposterior (AP) measures (S-SE, SE-N, ANS-PNS) increased almost as much as the vertical measures (S-PNS, SE-PNS, N-A, N-ANS) over the first 5 years. After 5 years of age there was significantly more vertical than AP growth. The size and shape changes that occurred were greatest between 0.4 and 1 years; yearly velocities decelerated regularly thereafter. Overall linear growth changes that occurred between 0.5 and 5 years of age (a span of 4.5 years) were generally greater than the changes in maxillary growth that occurred between 5 and 16 years (a span of 11 years). The linear measures showed a gradient of maturation, with the AP measures being more mature than the vertical measures. Male maxillae were less mature than female maxillae at every age.

Conclusions:

The maxilla undergoes its greatest postnatal growth change during infancy and early childhood, when relative AP growth and maturation are emphasized.

ABSTRACT

Objective:

To test the null hypothesis that orthodontic therapy with or without premolar extraction does not result in any difference in third molar impaction.

Materials and Methods:

Two groups were formed: 22 patients in one group with first premolar extractions and 22 patients in the other group without extractions. All patients were nongrowing subjects who had normal gonial angles and were skeletal Class I at the beginning of treatment. The available space for third molars, inclination of second and third molars, and angle between the second and third molars were evaluated. Also, the correlation of measured parameters and type of orthodontic therapy with the eruption of third molars was evaluated.

Results:

Of the third molars, 81.8% were impacted in the nonextraction group and 63.6% were impacted in the extraction group. Impaction of mandibular third molars was significantly correlated to the pretreatment and posttreatment inclination of third molars and the angle between the second and third molars. In the extraction therapy group, the retromolar distance increased significantly with a mean of 1.30 ± 1.25 mm.

Conclusions:

When the inclination of the third molar is inconvenient, the tooth may remain impacted even if there is enough retromolar space.

This listing of academic opportunities is provided as a free service to the profession and the community.

ALABAMA

Rank: 2 Orthodontic Instructor

University of Alabama at Birmingham School of Dentistry

Dept. of Orthodontics, Birmingham, AL 35294-0007

Contact: Dr. Chung How Kau, (205) 934-1289

FAX: (205) 975-7590 e-mail: ckau@uab.edu

FLORIDA

Rank: Commensurate with training & experience

Require: DMD/DDS or equivalent and cartificate in orthodontics from CODA accredited program. Advanced degree and or academic/research And/or ABO certification is desirable.

Nova Southeastern University

College of Dental Medicine/Orthodontics

3200 South University Drive

Fort Lauderdale, FL 3328-2018

Apply: www.nsujobs.com, job #993526

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Johnny JL Liaw,

Jae Hyun Park,

Fang Fang Tsai,

Betty MY Tsai, and

Wendy WT Liao