REVIEWS AND ABSTRACTS

Book reviews and article abstractsAlex Jacobson

Birmingham, Ala

THESIS ABSTRACTS

Variation in orthodontic treatmentplanning decisions of Class II casesbetween virtual 3D models andtraditional plaster study modelsJosh WhettenUniversity of Alberta, Edmonton, Alberta, Canada

Objective: The purpose of this study was to evaluatewhether the use of digital models would elicit treatment deci-sions that varied compared with traditional plaster models.

Methods: Pretreatment records of 10 patients with ClassII malocclusions were assessed by 20 orthodontists serving asthe variable group. The records were viewed at 2 time pointsat least a month apart, with the model format being changedat the second session. To serve as a control or standard, asecond group of 11 orthodontists evaluated the same 10 casestwice but examined the plaster models on both occasions.

Results: Orthodontists were scored on consistency oftreatment decisions based on surgery, extraction, and auxil-iary appliance use. Because the data consisted of matchedpairs and were nominal, the McNemar test and the kappastatistic were used to assess intrarater reliability. Addition-ally, a proportion of agreement was calculated for each group.Neither group showed statistically significant differences indecisions made.

Conclusions: Digital models are a valid tool for use intreatment planning, even for difficult orthodontic cases.

Alex JacobsonAm J Orthod Dentofacial Orthop 2005;128:2620889-5406/$30.00Copyright © 2005 by the American Association of Orthodontists.doi:10.1016/j.ajodo.2005.05.003

Paramedian palate morphology in theadolescent: a cone beam computedtomography studyKeith KingUniversity of Alberta, Edmonton, Alberta, Canada

Objective: The aims of this study were to (1) determinewhether a relationship exists between the available bone inthe paramedian palate (PP) and age, sex, and palatal morphol-ogy in growing patients; and (2) identify the most appropriatelocations for PP implantation, considering available bone and

interference of adjacent tooth roots.

262 American Journal of Orth

Methods: Cone beam computed tomography (CBCT)scans (NewTom 9000, Verona, Italy) were acquired in 183orthodontic patients (10-19 years old). Paracoronal views ofthe PP region were reconstructed (eFilm workstation, Mil-waukee, Wis) at 4, 8, and 12 mm posterior from the incisiveforamen, and measurements of bone height made in eachreconstruction at 3-, 6-, and 9-mm increments laterally fromthe midline to describe the PP.

Results: Significant variability in bone thickness was foundbetween locations and subjects. Male subjects had significantlygreater mean bone thickness in 6 of 9 locations measured. Ageand palatal measurements did not demonstrate a clinically usefulrelationship to bone thickness. At the location 4 mm posterior tothe incisive foramen and 3 mm lateral to the midline, 93% ofmale and 91% of female subjects met the criterion for implan-tation. At 8 mm posterior to the incisive foramen and 3 mmlateral to the midline, 86% of male and 58% of female subjectsmet the criterion for implantation.

Conclusions: The PP meets the orthodontic implantplacement criterion in growing patients over a wide agerange, with males having more bone availability than femalesin general. Age and palatal morphology are not valid predic-tors of bone height in the PP. Because of large variability ofbone thickness in this region, CBCT remains valuable beforeparamedian implant placement in growing patients. Becauseimplant placement in the midpalatal suture is contraindicatedin growing patients, the PP is a promising region for palatalimplant placements. CBCT allows accurate measurement ofPP bone height but adds cost and radiation exposure.

Alex JacobsonAm J Orthod Dentofacial Orthop 2005;128:2620889-5406/$30.00Copyright © 2005 by the American Association of Orthodontists.doi:10.1016/j.ajodo.2005.05.004

The effect of buccolingual rootangulation on the mesiodistal imageperception for panoramic imagesMariano GarciaUniversity of Alberta, Edmonton, Alberta, Canada

Objective: This study was carried out to assess the effectof buccolingual root orientation on the perception of mesio-distal angulation and parallelism for panoramic images.

Methods: A skull-typodont phantom was constructedaccording to cephalometric norms. The bases of the typodontwere partially sectioned so that the buccolingual orientationof 8 different teeth could be easily modified. The teeth chosen

were the maxillary right lateral incisor, the maxillary right

odontics and Dentofacial Orthopedics/August 2005