Head positioning error in cephalometric radiography--an implant study.

An experimental quantification of changes in position of cephalometric images caused by variation in head rotation in successive radiographs.

Design, evaluation, and use of a portable cephalometric cephalostat: the Porta-Stat (an X-ray subsystem).

A portable and light-weight cephalostat (Porta-Stat) is described. Device design, clinical use, and evaluation to verify accuracy are presented. The basic design uses a mainframe to which the image receptor, head, and X-ray source are referenced for standardization of image and magnification distortion in cephalometric radiographs. In a test to verify the accuracy of image reproducibility, no statistically significant difference was found from a fixed cephalostat system. The Porta-Stat cephalostat has verified accuracy essentially equivalent to traditional cephalometric radiography. Anecdotal case presentations show the usefulness of the Porta-Stat in the dental office, hospital radiology department, and operating room for case documentation, growth monitoring, treatment effect, and clinical research purposes. The device has proved to be useful in the management of TMJ syndrome, orthodontics, oral and maxillofacial surgery, otolaryngology, plastic surgery, neurosurgery, and craniofacial growth monitoring.

The design, fabrication, and use of a full-coverage bonded rapid maxillary expansion appliance.

A detailed design and step-by-step construction of a bandless indirectly fabricated and bonded rapid maxillary expansion appliance are presented. Four case reports demonstrate the use of the appliance in routine correction of posterior crossbite; in simultaneous correction of anterior crossbite, especially useful in cleft palate treatment; in combination with maxillary protraction; and in pre-expansion osteotomy cases. Various modifications of the basic appliance make it useful in treating a variety of orthodontic problems. Three of the cases reported have tantalum bone markers for enhanced ascertainment of orthopedic effect.

Component bone marker displacements revealed by image-corrected cephalometric analysis. A lateral cephalometric study of the cranium in normal and craniosynostosis--an implant study.

Displacement of bony component anatomy has not been comprehensively described in human cranial development. In this study, tantalum implants were used to define cranial bone position on serial cephalometric surveys. Image correction (ICCA method) was used to eliminate artifactual shift of component markers before serial analysis was used to define implant movement. In addition, applicable normative standards were used to assess all case presentations. Three normal subjects comprised a normal mixed longitudinal sample aged 2 to 84 months. Two plagiocephaly subjects were studied, one from 6 to 77 months and the other from 16 to 44 months of age. Three syndromic craniosynostosis subjects demonstrated both abnormal and normalized growth following craniotomy, from 14 to 45, from 0.5 to 5.5, and from 2 to 75 months of age. A pattern of backward rotation of cranial component anatomy was observed in three normal subjects and two plagiocephaly subjects. The posterior fossa (PF) showed the greatest growth activity, with displacement adjustments throughout the study, and the anterior cranial fossa (ACF) least growth activity, with imperceptible frontal bone movement after age 3 years. After traditional bifrontal craniotomy, an abnormal displacement growth pattern was observed from age 14 to 45 months in the patient with syndromic craniosynostosis (Pfeiffer syndrome). Extensive fronto-parietal "bossing" and grossly deficient movement in the PF were observed. However, after a bifrontal craniotomy that also crossed lambdoid sutures, a normalized pattern of displacement growth was observed in two Apert syndrome patients. These two patients with extensive syndromic craniosynostosis had cranial component pattern adjustments as in the normal and plagiocephalic subjects.

Image corrected cephalometric analysis (ICCA): design and evaluation.

Image corrected cephalometric analysis (ICCA) is a method for eliminating serial image parallax error. In a radiographic survey, image parallax is an inherent and random property of the two-dimensional image of the subject. Radiographs of the same subject taken at different times will be different in image parallax. This difference, parallax error, is routinely displayed between serial radiographic studies. Parallax error discourages the use of conventional serial cephalometric surveys for tracking and studying changes in discrete craniofacial structures lying outside the midsagittal plane, unilaterally disposed, or changing without bilateral symmetry. Anatomic outlines or discrete points of such structures would routinely display measurement perturbations caused by image parallax differences between surveys. The ICCA method eliminates this problem. Therefore, accurate serial measurements of bone marker point displacements are made possible with two-dimensional reconstructions of points lying in three-dimensional space. The method of ICCA was tested for accuracy by using zero time serial cephalometric surveys of five subjects. Mean implant error of 0.12 mm (SD = 0.1) was found between predicted (ICCA) and actual measured implant movement caused by the image parallax error. After applying this method, bone marker movements are unlikely to be caused by parallax error between conventional serial cephalometric studies. Furthermore, displacement growth can be related to the relocation of composite growth outlines and midline anatomic landmarks. One plagiocephaly case and one hemifacial microsomia case were used to demonstrate ICCA for growth and treatment effect documentation.

Five cases of DeMyer sequence: an interophthalmic dysplasia.

Five cases with vomero-septal-prolabium agenesis, four with premaxillary agenesis, and one with hemipremaxillary agenesis are presented. All five patients had complete clefts of the secondary palate. No known family history for craniofacial dysmorphia was reported. Height and weight ranged from 2nd to 10th centile. Psychological testing showed intelligent quotients of 121, 93, 72 for three patients; two were microcephalic with undetermined IQ, but severe generalized developmental delay. CT scans for the patient with the IQ of 72 and for one of the two microcephalic subjects showed normal brain structures. The other microcephalic patients had midline prosencephalic dysgenesis. Cephalometric analysis of the cranial base and interorbital dimension using normal standards and self indexing showed hypotelorism and small anterior cranial bases to be apparently related to reduced size of the sphenoid. An intact ethmoid, nasal bone, and crista galli appear to represent key anatomic differences in these patients as compared to classical holoprosencephaly sequence subjects. It was suggested that this pattern of midline facial agenesis may range from a solitary central incisor to the most severe variant presented. Using the embryologic classification, these subjects fall best under the heading of craniofacial dysplasia rather than cerebral craniofacial dysplasia, as a different type of interophthalmic dysplasia or DeMyer sequence.