Bolton Standards Research Articles

Cephalometric templates based on the Bolton standards

An accurate, simple, rapid method of cephalometric profile analysis is proposed. Templates, derived photographically from the 9-year through 18-year male-female Bolton standard tracings, are used to define the optimal locations for any selected hard or soft tissue dentofacial landmarks. Discrepancies between the ideal and actual positions of each landmark are immediately apparent and graphically reveal existing deformities. No tracing or measurements are required, as the analysis is performed directly on the patient's cephalogram. The construction of the templates and their application to clinical cases are described.

A cephalometric analysis of skeletal and dental changes contributing to Class II correction in activator treatment

The purpose of this investigation was to evaluate cephalometrically the mechanism of anteroposterior occlusal changes in activator treatment. The analysis used made it possible to relate alterations in the occlusion to sagittal skeletal and dental changes in the maxilla and mandible. The sample consisted of thirty Class II, Division 1 malocclusion cases treated successfully with activators during an average time period of 32 months. Before- and after-treatment head films in centric occlusion were analyzed. The occlusal line (OL) and occlusal line perpendicular (OLP) through sella were used for reference. Linear measurements were performed parallel to OL. The following results were found: (1) The improvement in occlusal relationships in the molar and incisor segments was about equally a result of skeletal and dental changes. (2) Overjet correction averaging 5.0 mm was a result of 2.4 mm more mandibular growth than maxillary growth, a 2.5 mm distal movement of the maxillary incisors, and a 0.1 mm mesial movement of the mandibular incisors. (3) Class II molar correction averaging 5.1 mm was a result of 2.4 mm more mandibular growth than maxillary growth, a 0.4 mm distal movement of the maxillary molars, and a 2.3 mm mesial movement of the mandibular molars. (4) When the findings were compared with longitudinal records of persons with normal occlusion (Bolton standards), activator treatment seemed to inhibit maxillary growth, move the maxillary incisors and molars distally, and move the mandibular incisors and molars mesially. Mandibular growth appeared not to be affected by activator treatment.

Attention of 4-month infants to discrepancy and babyishness

A set of four facial stimuli derived from the Bolton standards of craniofacial development representing a human male at 6 months, 3, 8, and 18 years of age were used in a test of Lorenz's concept of babyishness and of the discrepancy hypothesis. Each 4-month-old subject was habituated to a criterion with one of the four stimuli and then presented with one of the four as a new stimulus. The design and analysis permitted the response to a new stimulus to be broken down into a component attributable to the physical characteristics of the new stimulus and a part attributable to its discrepancy from the familiar standard. The data revealed longer looking at the infant facial stimulus, but no difference in a rating of affect accompanying fixation. This lent partial support to the babyishness concept for infant subjects. Both fixation and affect increased monotonically with magnitude of discrepancy. The increasing rather than curvilinear result presumably derived from the failure of these stimuli (which were common to the infant's experience) to generate extreme levels of subjective uncertainty.

A longitudinal study of morphological craniofacial patterns via P-A X-ray headfilms in cleft patients from birth to six years of age

652 P-A X-ray headfilms of 51 unilateral cleft lip and palate, UCLP; 27 bilateral cleft lip and palate, BCLP; and 62 isolated cleft palate, CP were studied longitudinally at 0—3 months, 4—6 months, and annually from 1:0—6:0 years. Breadth change, height change, and growth direction of nine paired landmarks were investigated by means of the rectangular coordinate system with right to left zygomatico-frontal suture (Zf) point line as the X-axis and the perpendicular line to this X-axis at the mid-point between the right and left Zf points as the X-axis. Major findings were: (1) Study of Sphenoid body, interorbital, bizygomatico-frontal suture, and bi-zygomatic arch breadths showed that BCLP had a significantly broader face than either UCLP or CP. An apparent tendency to hypertelorism still remained at 6:0 in this group while UCLP and CP groups were both close to the Bolton Standards. (2) Nasal and maxillary breadths of BCLP and UCLP were significantly wider during the first year than in CF, but they showed only a slight growth change after the age of one year, compared to constant growth in CF. (3) All marked structural differences disappeared by 6:0 suggesting the effects of lip and/ or palate surgery. (4) A slight cross-bite was found in UCLP and BCLP, but there was no such cross-bite in GP. (5) The effect of clefting was seen in mandi-bular dimensions where the bigonial notch was slightly broader than in non-cleft averages. (6) Upper facial height occlusal height, and posterior total facial height in each cleft group seemed to be larger than the Standard, though both maxillary height and gonial notch height approximated the Standard by 6:0 (7) From 023—6z0, there was no noteworthy difference among the cleft groups in either growth direction or facial symmetry of upper face and mandible. It was only in the mid-facial and dental areas that notable characteristics peculiar to the type of cleft were found. The landmarks of nasal aperture, maxilla, and dental arch showed a slight. medial displacement on the affected side, although the degree and amount depended on the cleft-type.

The short face syndrome

Cephalograms of twenty-seven untreated adult Caucasians, selected on the basis of a clinical impression of reduced lower facial height, were studied. Various linear and angular measurements were studied and compared to the Bolton standards. The short face syndrome SFS is a clinically recognizable facial type with reduced lower facial height as the common denominator. On the basis of the FPI (facial proportion index), the RH (ramus height), the OP-PP distance (or posterior maxillary height), and the SN:MP angle, two subgroups were distinguished in the SFS group. SFS, was characterized by a long ramus, sharply reduced SN:MP angle, an FPI close to 10, and a slightly reduced posterior maxillary height. In contrast, SFS 2 was characterized by a short ramus, a slightly reduced SN:MP angle, an FPI with values around or below zero, and a sharply reduced posterior maxillary height. The latter group was designated as vertical maxillary deficiency.