The effect of Frankel II and modified twin block appliances on the 'C'-axis: the growth vector of the dentomaxillary complex.

The recently determined 'C'-axis, the growth vector of the dentomaxillary complex, permits an evaluation of any meaningful growth changes thereto by the Frankel II and modified Twin Block functional appliances. Retardation of the velocity of change (mm/year) in length of the 'C'-axis did not occur. The angular relationship of the 'C'-axis to Sella-Nasion (theta) and to the palatal plane (alpha) were not altered in a clinically significant way.

Pilot study evaluating the effects of a cervical headgear on the C-axis: the growth axis of the dentomaxillary complex.

The C-axis, a growth vector for the dentomaxillary complex, is a means of quantifying complex maxillary growth in the sagittal plane through 3 key cephalometric measurements. This pilot study examined the effect of a cervical headgear, worn 8 to 10 hours per day, on the growth axis. The mean velocity of C-axis length increase in normally growing boys in the age range studied is 1.

The G-Axis: a growth vector for the mandible.

On the basis of the G-point, defined as the center of the largest circle that is tangent to the internal inferior, anterior, and lingual surfaces of the mandibular symphysis in the sagittal view, a growth axis and its direction are described for each gender from age six to 19.25 years. Incremental growth along the G-Axis, defined by Sella-G-point, is described by regression formulas with correlation coefficients of 0.

Extraoral appliances: A twenty-first century update.

With the locations of the centers of resistance of the dentomaxillary complex having recently been defined, and with the newly acquired knowledge of the critical interplay between part-time extraoral and full-time intraoral force systems, the basic designs of all types of extraoral appliances are discussed in depth. Armed with this information, the clinician can improve the efficiency of all extraoral appliances to obtain better dentomaxillary-complex growth control and negate or enhance appliance-induced intraoral force systems.

The Gable bend revisited.

Gable bends are frequently incorporated into a variety of loop configurations to provide appropriate moment-to-force (M/F) ratios in the controlled closure of space between individual teeth or groups of teeth. Appropriate magnitudes and occlusogingival locations of the Gable bends are shown to be vital to maintain the neutral position of the closing loop. Otherwise, the clinician has no meaningful reference point from which to judge the spring's activation to obtain the force aspect in the M/F ratio.

Condylar displacement related to mandibular symphyseal distraction.

This study was undertaken to determine the true nature of condylar displacements associated with mandibular symphyseal distraction osteogenesis. Earlier investigators have assumed that each mandibular half rotated about a point near the center of each condyle as viewed on a submental radiograph. In a 12-patient sample, 10 with tooth-borne symphyseal distraction and 2 with bone-borne symphyseal distraction, it was found that each condyle was laterally displaced in direct relationship to the amount of symphyseal distraction.