Forces Generated During Plush Animal Pacifier Use: A Pilot Study.

PURPOSE: Plush animal pacifiers (detachable weighted stuffed animals) have gained popularity. Although pacifiers have well-known benefits, they can also affect the development of the cranio-facial-respiratory complex. The purpose of this study was to study the forces gener- ated on the maxillary arch region during the use of plush animal pacifiers. METHODS: Products were tested using an Instron model 1011 machine. A fixture was developed to standardize the testing of the various brands. Each item tested was suspended on a pin eight mm from the pacifier shield, and the position of the Instron pushing apparatus was standardized throughout the testing. RESULTS: Generated forces from all Plush animal pacifiers tested fell in the range of 0.47 N to 0.7 N (47.9 g to 71.4 g). The force of the pacifier alone fell in the range of 0.05 N to 0.2 N (5.1 g to 20.4 g). CONCLUSIONS: When toy plush animals are attached to a pacifier, the forces transmitted to the nipple of the pacifier can exceed the 0.4 N minimum force (100 g equals 0.98 N) required to cause orthodontic tooth movement.

Functional comparison of pacifiers using finite element analysis.

BACKGROUND: Pacifiers have been shown to affect maxillary growth related to the anatomic structure of the palate and forces placed upon it during sucking. This study compares and evaluates the mechanical behavior of pacifiers of different design and size (i.e., fit), identified by brand and size, positioned in age-specific palatal models with respect to both contact area and force when subjected to peristaltic tongue function and intraoral pressure related to non-nutritive sucking. METHODS: Nonlinear finite element analyses were used to simulate dynamic mechanical interaction between the pacifiers and palates. Time-varying, external pressure loads were applied which represent intraoral pressure arising from non-nutritive sucking and peristaltic behavior of the tongue. The silicone rubber pacifier bulb was represented using a hyperelastic material model. RESULTS: Results from the finite element analyses include deformation, stress, strain, contact area, and contact force. Mechanical interaction was evaluated in terms of the spatial distribution of the contact area and force between the pacifier and the palate. The resulting palatal interaction profiles were quantitatively compared to assess how pacifier fit specifically affects the support provided to two areas of the palate, the palatal vault and the Tektal wall. CONCLUSIONS: Pacifiers interact with the palate differently based on their fit (i.e., design and size) regardless of whether they are labeled conventional or orthodontic. Finite element analysis is an effective tool for evaluating how a pacifier's design affects functional mechanics and for providing guidance on biometric sizing.

Computational simulation of pacifier deformation and interaction with the palate.

OBJECTIVES: The objective of this study is to demonstrate that computational finite element models can be used to reliably simulate dynamic interaction between a pacifier, the palate, and the tongue during nonnutritive sucking (NNS). The interactions can be quantified by the results of finite element analyses which include deformation, strain, stress, contact force, and contact area. MATERIALS AND METHODS: A finite element model was created based upon CAD solid models of an infant pacifier and palate. The silicone pacifier bulb is represented by a hyperelastic constitutive law. Contact surfaces are defined between the pacifier and palate. A time and spatially varying pressure load is applied to the bulb representing peristaltic interaction with the tongue. A second time-varying, periodic pressure representing NNS is applied to the model simultaneously. A large displacement, nonlinear transient dynamic analysis is run over two NNS cycles. RESULTS: Results from the finite element analysis show the deformed shape of the bulb with maximum principal elastic strain of 0.23 and a range of maximum principal stress on the palate from 0.60 MPa (tensile) to -0.27 MPa (compressive) over the NNS cycles. The areas of contact between the pacifier and the palate are shown in surface contour plots. CONCLUSIONS: A nonlinear transient dynamic finite element model can simulate the mechanical behavior of a pacifier and its interaction with the tongue and contact with the palate subject to NNS. Quantitative results predicting deformation, strain, stress, contact force, and contact area can be used in comparative studies to provide insight on how pacifiers cause changes in dental, orthognathic, and facial development.

Support for the use of thermoplastic bite impressions to aid in the identification of missing and unknown children.

This paper presents a response to the editorial opinion expressed in the position paper "Promotion of the Use of a Thermoplastic Material to Aid in the Identification of Unidentified Human Remains," published on page 14 of this issue of the JOURNAL OF THE MASSACHUSETTS DENTAL SOCIETY. No references were cited in that paper: Because the mission of the American Board of Forensic Odontology (ABFO) is to "promote and enhance the science of forensic odontology" and realizing that the ABFO Guidelines on bite mark evidence has failed law enforcement in several high-profile cases in the past, it is necessary to publish a referenced response addressing some of the statements that were made in the ABFO article.

Anatomy of a properly taken toothprints thermoplastic bite impression.

The Toothprints thermoplastic bite impression technique, like most procedures in clinical practice, is technique-sensitive. The biometric information available from the thermoplastic wafer is directly proportional to the care with which the technique is performed, as well as the cooperation and understanding of the child. Although the amount of information and the detail we obtain with the impression of only a few teeth (tooth size and occlusal anatomy are able to be digitized to 50 microns), along with saliva for scent dog tracking and cellular DNA analysis, it is a properly taken full-arch bite impression that would provide the best opportunity for infinite concordant matches for identification, should the need arise. With that in mind, below are the steps for properly taking a full-arch bite impression.