A Model for the Study of Development Processes in Dental Research

In studying developmental processes in dental research, variables other than chronological age must often be taken into account if we are to characterize di$erences in the developmental patterns of the groups under consideration. In particular, in addition to age, appropriate developmental models may have to incorporate cohort, time-of-measurement, and learning effects. One such model is described in this article and applied to caries development and gingival condition in the Nymegen Growth Study.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/66854/2/10.1177_00220345760550031201.pd

Precision and accuracy of CT-based measurements of masticatory muscles in patients with hemifacial microsomia

Objective: The objective of this study was to quantitatively assess masticatory muscle volumes in patients with hemifacial microsomia. Until recently, this congenital malformation was only studied in terms of restoring bony and skin morphologies. Study of the masticatory muscles, however, adds a new dimension. Materials and methods: Contiguous 1.5 mm CT scans were made using a Philips Tomoscan 350 in six patients with hemifacial microsomia and in one patient without asymmetry. These CT scans were processed by a Cemax 1500X 3D workstation. The volume of the masseter, temporal, and medial and lateral pterygoid muscles was measured from CT scans using three-dimensional (3D) segmentation followed by 3D imaging. The precision and accuracy of measurements of masticatory muscle volumes were investigated. The precision of 3D imaging was assessed by carrying out repeated measurements by two observers. The accuracy of the volume determination technique was assessed by scanning a piece of porcine muscle tissue with a known volume. Results: Intraobserver repeatability was near perfect, with the lowest abeing 0.96 (for the medial pterygoid muscle). All interobserver correlations were high (> 0.99). The accuracy of the method of measurement demonstrated differences ranging from 2.3% to 4.4%. Conclusion: Craniofacial soft tissue measurements obtained from CT scans in patients with hemifacial microsomia were accurate and reproducible but time consuming

The Eurocleft study: Intercenter study of treatment outcome in patients with complete cleft lip and palate. Part 1: Introduction and treatment experience

Objective: To calculate the amount of treatment and associated travel experienced by five groups of patients treated at different centers. (This data is related to outcomes and patient/parent satisfaction in subsequent papers in this series). Design: A longitudinal cohort study where results were previously reported at 9 years and follow-up measurements were obtained for 12 and 17 years. Setting: Multidisciplinary cleft services in Northern Europe. Subjects: 127 consecutively treated individuals with repaired unilateral complete cleft lip and palate. Main Outcome Measures: Numbers of surgeries and outpatient visits, number of visits, and treatment duration for early orthopedics and orthodontic treatment, associated travel time and difficulties. Results: The mean number of operations per center ranged from 3.5 to 6; length of orthodontic treatment from 3.3 to 8.5 years, and attendance from 49 to 94 visits; and for early orthopedics, 0 to 15 months of treatment, 0 to 17 visits, and 0 to 146 days in hospital. Conclusion: Protocols for the management of complete unilateral cleft lip and palate can vary dramatically in the burden of treatment imposed

Original article patterns of tooth agenesis in patients with Crouzon or Apert syndrome

Purpose: Dental agenesis is the most common anomaly of dental development and can be a component of a congenital syndrome. The purpose of this study was to evaluate the prevalence of agenesis and to describe patterns of tooth agenesis in patients with Crouzon or Apert syndrome compared with nonsyndromic controls. Patients and Metho