Longitudinal shape changes of the nasal dorsum.

This investigation quantifies childhood and adolescent growth changes of the upper and lower nasal dorsum and evaluates various aspects of the persons' morphology that relate to shape changes of the dorsum. A longitudinal sample of 37 French-Canadian girls, each having cephalograms at 6, 10, and 14 years of age, was evaluated. The 6- to 10-year interval was chosen to represent childhood growth; the 10- to 14-year interval represented adolescent growth.

Failure mode analysis of ceramic brackets bonded to enamel.

The purpose of this study was to evaluate in vitro the failure pattern of ceramic brackets bonded to enamel with a light-cured orthodontic adhesive. Five types of ceramic brackets and 125 incisors were used in the study. The brackets were bonded onto enamel with a light-cured orthodontic adhesive.

Scanning electron microscope (SEM) evaluation of clinical failures of single crystal ceramic brackets.

The objective of this work was to perform failure analysis on Starfire brackets that failed in clinical use. The failed brackets were examined with a scanning electron microscope (SEM) to obtain micrographs at magnifications of 20, 50, 100, and other magnifications, whenever necessary. With the aid of the micrographs, the fracture origin and the probable defect that initiated the fracture were identified.

Current concepts in education and research in orthodontics.

The science of dentistry is quickly advancing toward the 21st century. The constant innovations in dental material development, along with the ever-new concepts that are emerging in basic science and clinical research, are helping dentists to design methods of practice that have a more biologic and preventive substrate and a less restorative aim. As a result, all specialties of dentistry are undergoing constant changes in an effort to conform and manage the need of an educated, modern society.

Enamel fluoride uptake from an experimental fluoride-releasing orthodontic adhesive.

The purpose of this study was to evaluate quantitatively the fluoride uptake by enamel from an experimental visible light-cured orthodontic adhesive (VP-862) based on YbF3 filler. Sixteen contralateral premolars were extracted from 10 orthodontic patients and were classified in four groups (A, B, C, D) of four buccal surfaces each. Standardized enamel areas located on these surfaces were acid etched and were subjected to the following adhesive treatments: (A) VP-862; (B) Heliosit Orthodontic; (C) Heliobond + VP 862; and (D) Heliobond + Heliosit Orthodontic.

Bonding of ceramic brackets to enamel: morphologic and structural considerations.

The purpose of this study was to evaluate the form and microstructure of three types of ceramic bracket and to assess their interfacial surface shapes and bond strengths with visible light-cured and chemically cured adhesives after thermocycling. One monocrystalline and two polycrystalline structures were identified. The form of the bonding bases implied three types of bonding with the adhesive: a chemical bonding, a combination of mechanical retention and adhesion, and a combination of micromechanical retention and adhesion.