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PubMed1975

Sonar biparietal diameter growth standards in the rhesus monkey.

Serial sonar fetal cephalometry was performed on 67 pregnant monkeys (Macaca ulatta) with known breeding dates. A normal biparietal diameter (BPD) growth curve was constructed along four percentile divisions; namely, the 10th to the 24th, 25th to the 49th, 50th to the 74th, and the 75th to the 90th. It is shown that under normal conditions fetuses initially positioned in any one of these divisions will continue to grow within the confines of that same percentile range. This biologic phenomenon has not been previously reported. It is significant because it leads to a more precise separation of normal vs. suboptimal intrauterine growth.

Animals↗
PubMed1978

Biological variation in the biparietal diameter and its bearing on clinical ultrasonography.

Interpopulation differences in the term BPD and its relations to BW stress the need for each institution to analyze its own data. Variations in the BPD as a function of BW do not connote differences in the brain: body weight relationship, because the neurocrania of all term fetuses are not homomorphic. Differentiation of neurocranial form accounts for there being no consistent relationship between the BPD and calculated brain weight in interpopulation comparisons. The wide scatter of BPD and BW values in data from a single source challenges the wisdom of judging individual serial BPD readings by mean population values. Because the correlation between BW and the common indices of maternal size (stature, weight, and surface area) is too low (r = 0.27, 0.27, and 0.35, respectively) to provide a useful means of determining the fetal growth potential, each fetus should be used as its own control in serial cephalometry.

Birth Weight↗
PubMed1983

Effect of maxillary osteotomy on subsequent craniofacial growth in adolescent monkeys.

LeFort I osteotomy was performed on seven adolescent Macaca fascicularis monkeys to study its effect on the subsequent dentocraniofacial growth. Eight adolescent monkeys were used as controls. Tantalum implants were inserted at predetermined areas in certain craniofacial bones of all monkeys. For stereometric cephalometry, implants were placed in both the left and right sides of the facial bones. Lateral cephalometric radiographs of all monkeys were taken prior to and immediately after metallic implant placement, immediately after maxillary osteotomy, and thereafter every 4 weeks during the postsurgical period. At least two cephalograms were taken on each occasion, one with the teeth in occlusion and the other with mouth wide open. The latter was used to view the mandibular condyle adequately. These findings suggest that the maxillary osteotomy did disturb the vertical growth of the maxilla at the PNS and retarded the horizontal growth at the premaxilla. The anterior growth of the maxilla and mandible and the vertical growth of the face were substantially reduced. The most interesting finding was also a reduction of the mandibular growth in all of its dimensions. The rate and the amount of reduced anterior mandibular growth were found to be coordinated with the anterior maxillary growth which resulted in all animals showing a normal overjet, overbite, and occlusion throughout the postsurgical observation period.

Animals↗
PubMed1984

Growth of lips in two dimensions: a serial cephalometric study.

The effect of growth on the cross-sectional area of the lips was studied radiographically on 168 lateral cephalometric films of 28 persons, taken every 2 years from the age of 8 to the age of 18 years. All subjects studied had received no orthodontic treatment, and the total lip outline as it is seen on the lateral cephalogram was traced and calculated by computerized cephalometry. This method of calculating the total lip area, instead of relating lip growth to a single lip point, was selected in order to avoid any effect that positional changes of the lips may have and subsequently superimpose on lip changes resulting from growth. Increase in total lip area, in both numerical and proportional terms, was observed from age 8 to age 18 years. The largest incremental growth increase for both lips took place between the ages of 12 and 14 years, while no significant changes were observed after the age of 16. Tested growth changes for sex differences revealed statistically significant sexual dimorphism, with larger maxillary lip area in males at ages 10, 12, 14, 16, and 18 and larger mandibular lip area at 18 years of age, while the females showed significantly larger mandibular lip area at age 12.

Adolescent↗
PubMed1985

Cephalometric analysis of condylar adaptations to altered mandibular position in adult rhesus monkeys, Macaca mulatta.

Morphological adaptation to altered position of the mandible was investigated in 19 young adult rhesus monkeys (n = 10 experiment and 9 control). The experimental animals had a bite-splint cemented to the maxillary dentition which opened the bite interincisally by 15 mm and was worn continuously for 48 weeks. Lateral radiographic cephalograms were taken prior to the experiment and at 12-week intervals thereafter. Computerized cephalometry, facilitated by the use of radio-opaque bone markers, was used to assess changes in mandibular position and morphology. An immediate effect of the bite-splint was the clockwise rotation (opening) of the mandible and anterior translation of the condyle on the articular eminence, much as occurs normally during jaw depression. During the next 48 weeks, the mandible (1) rotated anti-clockwise (closed) due mainly to antero-superior displacement of the maxilla and intrusion of the mandibular dentition and (2) underwent a significant increase in length (p less than 0.05). These findings indicate that the mandibular condyle of young adult monkeys is capable of small, but biologically significant, compensatory growth after displacement.

Adaptation, Physiological↗
PubMed1992

Tooth contacts in eccentric mandibular positions and facial morphology.

Correlations between facial morphology and tooth contacts in excursive mandibular positions were studied in 75 men aged 20 to 33 years. The morphology of the dentition was verified on dental casts and the face was measured by use of roentgen cephalometry. No correlation was observed between facial morphology and the number of tooth contacts in the retruded position; however, wide dental arches and jaws displayed many contacts on protrusion. Numerous contacts on the functional side in group function were noted in individuals with a facial morphology associated with distal occlusion, such as Angle class II, division 1. Wide dental arches were associated with multiple functional-side contacts whereas tooth contacts on the nonfunctional side were related to the inclination of the mandible. A "long-face" morphology was related to contacts on the nonfunctional side. There was a negative correlation between the extent of the overbite (vertical overlap) and the number of tooth contacts on the nonfunctional side.

Adult↗
PubMed1991

Screw fixation after mandibular sagittal split osteotomy: an intra-oral approach.

Intra-oral, rigid, non-compressive fixation was used in a feasibility study in 10 consecutive sagittal split osteotomies using two 3.5 or 2.7 mm diameter AO screws on each side. Seven patients were prognathic, three were retrognathic, and two had severe mandibular asymmetry. Lower third molars were removed concurrently in three patients. Horizontal and vertical stability was assessed by means of repeated, digitised cephalometry before operation, at 24-48 h and at 6 months. Intermaxillary fixation (IMF) was necessary during the first 48 h in one patient where the lingual fragments were too small. Intermaxillary elastics were used later in three patients. This method was straightforward, reliable, required no skin incisions and stability was similar to that following the use of transbuccal screw fixation. Mean horizontal relapse at 6 months (0.6 mm; maximum: 1.5 mm) was 8% of operative movement. Unsatisfactory occlusion (anterior open bite) necessitated removal of screws at 28 days in one patient. This was carried out intra-orally under local anaesthesia. These results suggest that stable, screw fixation for sagittal split osteotomies can be achieved without recourse to an external approach.

Adolescent↗
PubMed1990

Effects of unilateral premature fusion of the zygomaxillary suture on the growth of nasomaxillary complex.

Unilateral premature fusion of the zygomaxillary suture was produced in 2-week-old guinea pigs by immobilization with methyl-cyanoacrylate adhesive. The effects of sutural fusion on the growth of the nasomaxillary complex were evaluated by radiographic cephalometry with implants, and histologic assessment. The immobilization successfully constrained the anteroinferior displacement of the maxilla and zygomatic bone on the fused side. Compensatory responsive remodeling at adjacent sutures and in certain regions of the nasomaxillary complex was observed. Developmental asymmetry was found when the fused side was compared with the nonfused side. No gross anatomic asymmetry of the facial complex as a whole, however, was detected. Adaptive compensation involving periosteal bone deposition occurred at the junction of the lower maxillary process and the maxilla proper on the fused side. This, together with periosteal bone resorption in corresponding areas on the nonfused side served to offset any developmental asymmetry that might have occurred, thus leading to a compensatory preclusion of gross anatomic asymmetry.

Analysis of Variance↗
PubMed1991

Fetal cleft lip repair in rabbits: postnatal facial growth after repair.

We have previously described a model for in utero cleft lip repair in rabbits. Cleft lip and alveolus (CL) were created in fetal rabbits at 24 days gestation (term, 31 days). In this study, postnatal maxillary growth was evaluated in three groups of animals: 1) unoperated controls, 2) unrepaired CL, and 2) repaired CL. The animals were killed at 4, 12, and 26 weeks after birth. Direct cephalometry was performed on dry skulls to evaluate premaxillary width, anterior maxillary length and width, and posterior maxillary width. The results of this study indicate that rabbits that undergo an in utero CL procedure, with or without repair, exhibit no significant decrease in maxillary length and width when compared with controls.

Alveolar Process↗
PubMed1995

Fetal and postnatal growth to age 2 years by mother's country of birth.

The objective of this study was to measure the physical growth of fetuses and infants in an inner city health district in the north of England and to compare their growth profiles according to mother's country of birth (British Isles or Indian subcontinent). The study was part of the Central Manchester Child Growth Project, a prospective longitudinal study of fetal and postnatal growth and development in a sample from the geographically-defined Central Manchester Health District. Data were collected from the beginning of the second trimester of pregnancy to the age of 2 years. One-hundred seventy-four singleton infants born at term ( > or = 37 weeks) had serial antenatal cephalometry every 3 weeks from the beginning of the second trimester and had serial head, length and weight measurements at birth and at the ages of 6, 13, 26, 52 and 104 weeks. Infants of Indian-born mothers tended to be lighter at birth than those of locally-born mothers, but the difference was not due to lower accumulation of soft tissue. Body length from 6 to 52 weeks in both groups of infants was similar. The major finding was the reduced head size in infants of Indian-born mothers, the difference being significant among boys, evident from mid-pregnancy and persisting postnatally to age 2 years. Reduced fetal growth is associated with the development of cardiovascular disease in adulthood, mortality from ischaemic heart disease being specifically linked with head size at birth. The reduced head size of boys of Indian-born mothers is of interest because male immigrants from the Indian subcontinent who live in England have an increased incidence of non-insulin dependent diabetes and a substantial excess mortality (standardised mortality ratio 313 at ages 20-29) from ischaemic heart disease.

Bangladesh↗
PubMed1988

Linear changes of the maxillary and mandibular lips.

This investigation was designed to assess the growth effect on the linear dimensions of human lips from childhood to adulthood. By means of serial computerized cephalometry, the changes in lip length and thickness were studied in 32 untreated male and female subjects from 8 to 18 years of age. It was observed that the maxillary and mandibular lips, under the influence of growth, increase in both dimensions with the advancement of age. During the period studied, the length and thickness of the lips of the male subjects exhibited greater increases both proportionally and numerically than the corresponding dimensions of female lips.

Adolescent↗
PubMed1989

Comparison of the dentofacial patterns for native Greek and American-Caucasian adolescents.

The study of the craniofacial relations and variations in man has long been used to differentiate various racial groups in physical anthropology. Morphologic features of different races and ethnic groups are not randomly distributed but appear in geographic clusters. Richardson wonders whether there is only one race, comprising ethnic groups separated by cultural, climatic, and geographic boundaries, causing subtle changes in facial morphology. Since the introduction of roentgenographic cephalometry in orthodontics, several methods of analysis have been developed for clinical diagnosis and treatment planning. Also, these methods have been used to establish the cephalometric norms of different ethnic groups: American Negro, Australian aborigine, American Mexican, Norwegian, Indian, Japanese, Swedish, and Iranian. Sassouni, Ricketts, and others have concluded that norms differ between Caucasians and other ethnic and racial groups. Ethnic differences in facial traits do exist. Awareness of the normal dentofacial pattern of each ethnic group will undoubtedly ensure better success of treatment to establish optimal facial harmony. These conclusions prompted the present investigation, which compares Greek and American-Caucasian dentofacial patterns of adolescents, and provides information on the facial characteristics of Greek adolescents. To date, no similar study has been made.

Adolescent↗
PubMed1991

Soft-tissue and dentoskeletal profile changes associated with mandibular setback osteotomy.

The aims of the present retrospective cephalometry study were (1) to describe the interrelationships of the soft-tissue and dentoskeletal profiles after total mandibular setback osteotomies and (2) to detect whether there were any cephalometric variables that could contribute to an accurate prediction of the surgical effect on the soft-tissue profile. The presurgical and postsurgical lateral cephalograms of 50 consecutively treated patients (37 females and 13 males) were used; these patients had received combined orthodontic-surgical management of mandibular prognathism by means of a bilateral vertical ramus osteotomy with an extraoral approach. At the time of surgery, their ages ranged from 17 to 41 years. Lateral cephalograms with the teeth in habitual occlusion taken before and approximately 1 year after surgery were available for all patients. A computerized cephalometric appraisal, named profile analysis, was developed and used, including variables corresponding to sagittal and vertical relationships of skeletal and soft-tissue profiles, incisal relationships, soft-tissue thickness, and lip morphology. The statistical elaboration of the data was made by means of paired t test, Pearson's product-moment coefficient correlation, and multiple regression analyses. The assessment of the results disclosed that considerable facial changes and improvement took place after the surgical procedure. The skeletal and soft-tissue facial profiles were straightened and the posture of the lips was improved. The normal incisal relationship achieved became influential on the soft tissues overlying both incisors and led to a better lip competence and posture. Posterior movement at points B and Po was accompanied by reductions ranging from 91% to 103% of the corresponding soft tissues. The presence of both significant correlation coefficients (p less than 0.05) and high r square values (greater than 0.70) in the multiple regression analysis for the osseous tissue variables N-B and N-Po, alone or together with the overjet and S-N-B angle, respectively, reflected their high prediction value with regard to the sagittal relationship of the lower lip, its thickness, and the soft-tissue thickness at the chin area. The findings of Pearson's product-moment coefficient correlation also indicated that the operative changes of the thickness of the upper lip, the lower lip, and the soft tissue at the chin region are influenced by the initial preoperative thickness of the area.

Adult↗
PubMed1992

Mandibular displacement in Angle Class II, division 2 malocclusion.

The effect of the treatment of Angle Class II, Division 2 malocclusion was studied in 22 children by x-ray cephalometry and by recording the relation between the retruded and the intercuspal mandibular positions. The treatment was performed in three phases. In the first phase the upper incisors were proclined, and the deep bite was corrected with an upper removable plate. In the second phase the distal occlusion was corrected with an activator. The result was retained in the third phase with a second activator designed for retention. The relation between the retruded (RCP) and the intercuspal (ICP) mandibular positions was recorded with wax bites and dental casts mounted in a modified gnathothesiometer. The anteroposterior distance between RCP and ICP was large before the start of the treatment. The distance was unchanged after proclination of the upper incisors and correction of the deep bite but decreased after correction of the distal occlusion and increased again somewhat during the retention phase. The proclination of the upper incisors and the correction of the deep bite (phase one of the treatment) did not result in mandibular anterior positioning. This fact and the results of the recordings of the relation between RCP and ICP were interpreted as evidence that the mandible is not posteriorly displaced in Class II, Division 2 malocclusion.

Activator Appliances↗
PubMed2005

The interaction between changes in upright mandibular position and supine airway size in patients with obstructive sleep apnea.

INTRODUCTION: The purpose of this study was to investigate the interaction between upright mandibular position change and supine upper airway size in men with obstructive sleep apnea fitted with titratable oral appliances. METHODS: Baseline supine cephalometry before placement of the oral appliance and after titration with the oral appliance in place were undertaken in 14 patients, and upright mandibular position change was evaluated with and without the titrated oral appliance in place with a DigiGraph workstation (Dolphin Imaging Systems, Valencia, Calif). RESULTS: The apnea-hypopnea index was significantly reduced after titration of the oral appliance (P < .01). Upright mandibular position change was associated with significant vertical (P < .01) and horizontal (P < .01) mandibular repositioning. The size of the supine velopharynx (P < .05), but not the supine oropharynx, was significantly enlarged at the titrated mandibular position. The supine oropharyngeal size change was correlated with the upright horizontal repositioning of the mandible (r = 0.69, P < .01). CONCLUSIONS: Evaluation of upright mandibular position changes with the DigiGraph workstation enables one to predict supine oropharyngeal enlargement with oral appliance therapy. Dose-dependent effects of the horizontal component of upright mandibular protrusion on supine oropharyngeal size in addition to velopharyngeal enlargement might contribute to oral appliance effectiveness in obstructive sleep apnea patients.

Adult↗
PubMed2005

Comparing digital and conventional cephalometric radiographs.

With the introduction of digital cephalometry in orthodontics, many clinicians have cephalometric radiographs for a patient taken on 2 different cephalostats. Comparing these images is difficult because of differences in magnification between the 2 units. This article describes how to determine the magnification of a cephalometric radiograph and how to change the dimensions of a digital image to match a conventional image.

Cephalometry↗
PubMed2005

Facial soft tissue thickness in Japanese female children.

Facial reconstruction techniques used in forensic anthropology are based on soft tissue thickness measurements. Many studies of facial tissue thickness in adults have been published that take racial background into account. However, the only data on facial thickness in children are derived from studies of American, British, and Hispanic children. The authors therefore measured facial tissue thickness in Japanese children, with the aim of providing data for producing accurate facial likenesses and to evaluate matching of skull-photo superimposition images. Cephalometric X-ray images give an approximately 10% enlargement from true size and can demonstrate the relationship between soft and hard tissue. Facial soft tissue thickness was measured at 12 anthropological points using X-ray cephalometry.

Adipose Tissue↗