Analysis and design of rolling-contact joints for evaluating bone plate performance.

An apparatus for testing maxillofacial bone plates has been designed using a rolling contact joint. First, a free-body representation of the fracture fixation techniques utilizing bone plates is used to illustrate how rolling contact joints accurately simulate in vivo biomechanics. Next, a deterministic description of machine functional requirements is given, and is then used to drive the subsequent selection and design of machine elements.

Design and experimental evaluation of adjustable bone plates for mandibular fracture fixation.

Conventional bone plates are commonly used for surgical mandibular fracture fixation. Improper alignment between bone segments, however, can result in malocclusion. Current methods of fixation require a surgeon to visually align segments of bone and affix a metal plate using bone screws, after which little can be done to adjust alignment.

Multilocularity as a radiographic marker of the keratocystic odontogenic tumor.

Purpose: The purpose of this study was to answer this clinical question: When a patient presents with a radiolucent lesion of the mandible presumed to be an odontogenic cystic lesion, to what extent is the radiographic finding of multilocularity predictive of a final diagnosis of keratocystic odontogenic tumor (KCOT)?

Materials And Methods: The study sample was derived from the population of patients who presented to the Department of Oral and Maxillofacial Surgery, Massachusetts General Hospital for evaluation and management of suspected mandibular lesions from January 1991 through January 2009. Subjects were eligible for study inclusion if there was a final histologic diagnosis of KCOT or dentigerous cyst. The predictor variable was radiographic appearance of the lesion and was grouped into 2 categories (unilocular or multilocular).

Accuracy of reconstructed images from cone-beam computed tomography scans.

Introduction: The aim of this study was to determine whether 2-dimensional (2D) images produced from cone-beam computed tomography (CBCT) images taken with an iCAT scanner (Imaging Sciences International, Hatfield, Pa) can substitute for traditional cephalograms.

Methods: Lateral and frontal cephalograms were taken of a radiographic phantom with known dimensions. Landmarks on the 2D images were traced and measured manually by 2 examiners and then digitally in Dolphin 10 (Dolphin Imaging Sciences, Chatsworth, Calif) by the same examiners.

Clinical application of curvilinear distraction osteogenesis for correction of mandibular deformities.

Purpose: To report the use of a semiburied curvilinear distraction device, with a 3-dimensional (3D) computed tomography treatment planning system, for correction of mandibular deformities.

Materials And Methods: This was a retrospective evaluation of 13 consecutive patients, with syndromic and nonsyndromic micrognathia, who underwent correction by curvilinear distraction osteogenesis. A 3D computed tomography scan was obtained for each patient and imported into a 3D treatment planning system (Slicer/Osteoplan).

How do feedback and instructions affect the performance of a simulated surgical task?

Purpose: This study was conducted to objectively evaluate the effect of feedback and instructional material on the acquisition of surgical psychomotor skills for a model system based on mandibular fracture repair.

Materials And Methods: This study was a prospective cohort study comprised of students in the preclinical years of dental or medical education. The students were divided into 4 groups and exposed to different levels of feedback/written instructions (including none) in the testing environment.

Comparison of wound management methods after removal of maxillofacial osseous lesions.

Purpose: To evaluate outcomes associated with choice of wound management, ie, primary closure or healing by secondary intention, of osseous defects after excision of maxillofacial bone lesions as a guide to clinical practice.

Patients And Methods: Using a retrospective cohort study design, we enrolled a sample composed of subjects treated for jaw lesions between 1995 and 2003. The primary predictor variable was the wound management choice of the residual jaw defect, classified as primary closure or healing by secondary intention.

Range of curvilinear distraction devices required for treatment of mandibular deformities.

Purpose: The purpose of this study was to determine the range of fixed trajectory curvilinear distraction devices required to correct a variety of severe mandibular deformities.

Materials And Methods: Preoperative computed tomography (CT) scans from 18 patients with mandibular deformities were imported into a CT-based software program (Osteoplan). Three-dimensional virtual models of the individual skulls were made with landmarks to track movements.

Analysis of skeletal movements in mandibular distraction osteogenesis.

Purpose: The purpose of this study was to use geometric parameters of movement, calculated from 3-dimensional computed tomography (CT) data, to determine the curvilinear distractor dimensions required to correct mandibular deformities in a series of patients.

Materials And Methods: Preoperative CT scans from 15 patients with symmetric (n = 5) and asymmetric (n = 10) deformities were imported into a CT-based software program (Osteoplan; an open-source visualization application developed by Gering et al at the Surgical Planning Laboratory [SPL, Brigham and Womens Hospital, Boston, MA]). The software was used to reconstruct virtual 3-dimensional models from these scans.

Types, frequencies, and risk factors for complications after third molar extraction.

Objectives: The study objective was to identify the types, frequency, and risk factors for complications after third molar (M3) extractions.

Study Design: This retrospective cohort study consisted of patients who had 1 or more M3s removed between 1996 and 2001. Risk factors were grouped into demographic, general health, anatomic, and operative.