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PubMed1998

[Cranial development after corrective skull surgery in craniosynostosis].

Craniofacial development may be potentially implicated after vault corrections in cases of craniosynostosis. The aim of this prospective study was the investigation of the surgical effect on calvaria growth, correlating the percentiles of a group of patients before and after craniosynostosis correction in relation to the normal percentiles of growth. The patient population consisted of 71 children; the postoperative follow-up time in 57 patients was more than 12 months. Of the children followed up, 36 were male and 21 female. Thirty-six cases involved untreated non-syndromic craniosynostosis; the remaining 21 were syndrome cases. The patient ages ranged from 16 to 27 months. In 11 cases correction of an occipital craniosynostosis was carried out. The fronto-occipital circumference was registered in accordance with Prader's percentile table. The operative method included a fronto-parietal craniotomy, the temporary removal and shaping of the fronto-orbital band and a vault cranioplasty. During follow-up 13 patients treated with fronto-orbital advancement in cases of isolated craniosynostosis remained in the registered percentile curve. In 13 patients a change to a lower percentile curve was confirmed; 1 patient changed to a higher curve. In cases of syndromic craniosynostosis 10 patients remained in the post-operatively registered percentile curve; 8 patients changed to a lower and 1 patient to a higher percentile curve. No growth restriction of the reshaped calvaria after surgical correction of craniosynostosis was observed. No significant difference was found in the potential calvaria growth between syndromic and isolated craniosynostosis.

Child, Preschool↗
PubMed1995

Dentofacial growth in orthodontically treated and untreated children with juvenile chronic arthritis (JCA). A comparison with Angle Class II division 1 subjects.

The changes in craniofacial growth and development of dental occlusion were studied in children with juvenile chronic arthritis (JCA), and treatment with functional orthodontic appliances (activators) was tested in both JCA and healthy children with distal occlusion. Fifteen JCA children with Angle Class I occlusion and 15 JCA children with Angle Class II malocclusion were followed longitudinally and compared with 23 healthy children with Angle Class II malocclusion. The facial growth of the JCA children without need of orthodontic treatment mainly followed the normal pattern while the JCA children with Angle Class II malocclusion had a deviating facial morphology, which became more abnormal during growth. During the orthodontic treatment period a slight improvement was seen in mandibular positions in the sagittal and vertical planes in both treated groups, but the changes were more marked in the healthy children. None of the treated groups attained completely normal facial morphology, but in most children the occlusion improved and could be classified as normal. The morphology achieved by treatment largely remained the same during the follow-up period and relapse was seen only in a few children. JCA children with minor skeletal discrepancies can be satisfactorily treated during growth with functional orthodontic appliances, possibly in combination with fixed appliances. Even if skeletal changes in response to orthodontic treatment are rather limited, these changes combined with the improvement in dental occlusion obtained through treatment may result in better dentofacial aesthetics. Furthermore, jaw functions are likely to improve which also might benefit the patient from a psychosocial point of view.

Activator Appliances↗
PubMed1990

[A study of the relationship between the capacity of oral cavity proper and skeletal malocclusions].

A new method was developed for evaluating the quantitative capacity of the oral cavity proper with a three dimensional measurement system, and this was used to measure the capacity in 50 cases of adult female malocclusions. Morphologies of the dental arches, palates and maxillo-facial structures were measured on dental casts and both P-A and lateral cephalograms. Correlation coefficients were calculated between those measurements and the capacity of the oral cavity. Results are shown below: 1. Class III cases were statistically larger than classes I and II in the capacity of the oral cavity proper but there were no significant differences between those of class I and class II. 2. There were no significant differences among classes I, II or III in the maxillary capacity of the oral cavity proper. Class III, however, was significantly larger than classes I and II in the mandibular capacity of the oral cavity proper. 3. There was no significant difference among the three types of palatal morphology: Horizontal, Convex, and Concave. 4. Porions where high correlations were shown were different for classes I, II and III as to the relationship between both the dental arch length and width, and the capacity of the oral cavity proper. The general indication was that width was more related to the size of the capacity of the oral cavity proper than length was. 5. There were significant correlationships between the capacity of the oral cavity proper and maxillo-facial skeletal size in class I, the vertical dimension in class II, and the mesio-distal dimension in class III for the mandibular and maxillary measurements of both P-A and lateral cephalograms.

Cephalometry↗
PubMed2003

Long-term results of the two-stage palatoplasty/Hotz' plate approach for complete bilateral cleft lip, alveolus and palate patients.

PURPOSE: To investigate the effects of the two-stage palatoplasty combined with the Hotz' plate on craniofacial development in patients with bilateral complete clefts. MATERIAL AND METHODS: Lateral and frontal cephalograms of two-stage palatoplasty/Hotz' plate group (n=10), one-stage palatoplasty group (n=11), and a non-cleft group (n=11), were evaluated at 6, 8, 10 and 12 years of age. The unpaired Student's t-test and Scheffe's F test (p<0.05) were applied. RESULTS: At 6 years the posterior upper facial height (PUFH) and PUFH/PFH ratio were greater in the two-stage group. At 10 years the PUFH, maxillary depth, convexity and ANB angle were greater in the same group. At 12 years, maxillary depth and ANB angle were also greater in this group. In the one-stage group, the L1/Mp. angle, PUFH and PUFH/PFH ratio were smaller when compared with the non-cleft group, whereas the palatal plane/SN angle was greater. In both cleft groups, the I.I. angle and tongue-PTM' distance were greater, and the U1/SN angle was smaller when compared with non-clefts. The UC-UC' and the ratios UC/MAX and UC/LC of both cleft groups were also smaller when compared with non-clefts. The ratio UM/MAX of the one-stage group was smaller when compared with the non-cleft group. CONCLUSION: The two-stage palatoplasty in combination with application of the Hotz' plate had good effects on the maxillary growth up to the age of 12 years.

Alveolar Process↗
PubMed2000

Treatment and posttreatment craniofacial changes after rapid maxillary expansion and facemask therapy.

The aim of this study was to evaluate treatment and posttreatment dentoskeletal changes in 2 groups of subjects with Class III malocclusions. Subjects were treated with a bonded acrylic-splint expander and a face mask, and the optimal timing for this treatment protocol was assessed. The treated sample (29 subjects) was divided into 2 groups according to the stage of dental development. The early treatment group consisted of 16 subjects in the early mixed dentitional (erupting permanent incisors and/or first molars), whereas the late treatment group consisted of 13 subjects in the late mixed dentition (erupting permanent canines and premolars). Cephalograms were available at 3 time periods: T(1), pretreatment, T(2), end of active treatment, and T(3), posttreatment. The mean T(1)-T(2) interval (active treatment period) and the mean T(2)-T(3) interval (posttreatment period) were approximately 1 year each in both treatment groups. None of the patients wore any skeletal retention appliance during the posttreatment period (T(2)-T(3)). Groups of subjects with untreated Class III malocclusion were used as controls at both observation intervals. A significant increase in the sagittal growth of the maxilla was seen only when treatment was performed in the early mixed dentition. A restraining effect on mandibular growth rate associated with a more upward and forward direction of condylar growth was found in both treatment groups. An increase in vertical intermaxillary relationships was observed in Class III patients treated in the late mixed dentition. Posttreatment, the Class III craniofacial growth pattern was re-established in the absence of any skeletal retention appliance. Relapse tendency affects the sagittal growth of the maxilla in the early treated subjects and the sagittal position of the mandible in the late treated subjects. Orthopedic treatment of Class III malocclusion in the early mixed dentition is able to induce more favorable craniofacial adaptations than treatment in the late mixed dentition.

Age Factors↗
PubMed2001

Clinical application and effects of the Forsus spring. A study of a new Herbst hybrid.

BACKGROUND: The best known of the fixed functional appliances are the Herbst appliance and the Jasper Jumper. The Forsus spring is a new development which has been tested in a clinical study to establish when it can be used and to compare it with its predecessors. PATIENTS AND METHOD: The Forsus spring was used over a period of 4 months to treat 13 patients with an average age of 14.2 years with Class II malocclusion. RESULTS: Evaluation of the lateral cephalograms showed that dental effects accounted for 66% of the sagittal correction. The sagittal occlusal relations were improved by approximately 3/4 of a cusp width to the mesial on both the right and left side as a result of distal movement of the upper molars and mesial movement of the lower molars. Retrusion of the upper and protrusion of the lower incisors reduced the overjet by 4.6 mm. Intrusion and protrusion of the lower incisors reduced the overbite by 1.2 mm. The occlusal plane was rotated by 4.2 degrees in clockwise direction as a result of intruding the lower incisors and the upper molars. The maxillary and mandibular arches were expanded at the front and rear during treatment.--Evaluation of a questionnaire filled in by the patients after 2 months of treatment showed that approximately half of them had experienced difficulties in brushing their teeth. The main problem, however, was the restriction experienced in the ability to yawn. Overall, two thirds of the adolescents found the Forsus spring better than the appliance previously used to correct their Class II malocclusion, such as headgear, activator or Class II elastics. CONCLUSION: The Forsus spring has stood the test in clinical application. It is a good supplement to the Class II appliance systems already available.

Adolescent↗
PubMed2000

Diagnostic criteria for pseudo-Class III malocclusion.

The aim of this study is to identify the diagnostic criteria for pseudo-Class III malocclusion and compare it with Class I malocclusion in the southern Chinese population. Sixty-seven patients (mean age, 10.9 +/- 1.8 years) were included in this study; 36 patients represented pseudo-Class III malocclusion. Selection criteria included the following: (1) anterior crossbite (at least 2 incisors with negative overjet and overbite); (2) mandibular displacement; (3) all patients were southern Chinese who had been followed after the growth spurt, none had developed a skeletal Class III malocclusion; (4) the patients were treated for an average of 7 months to procline upper incisors and retrocline lower incisors. None of the cases received any treatment that might affect skeletal growth. Thirty-one patients with Class I malocclusion were included in the Class I malocclusion group for the comparison of dentoskeletal characteristics with the pseudo-Class III malocclusion group. Selection criteria included the following: (1) skeletal Class I malocclusion with normal overjet and overbite, (2) mild to moderate crowding with Class I molar relationship, (3) straight facial profile. The following were included in the assessment of pseudo-Class III malocclusion cases: (1) family history, (2) molar and canine relationships at habitual occlusion and centric relation, and (3) dentoskeletal morphology. The results were that 72% of the examined cases in the pseudo-Class III malocclusion group showed no family history and 75% showed Class I molar relationship at habitual occlusion. Compared with the Class I malocclusion group, subjects in the pseudo-Class III malocclusion group showed a significantly decreased midface length, increased maxillary-mandibular difference, more retroclined upper incisors, and a retrusive upper lip. In conclusion, a pseudo-Class III malocclusion is characterized by retroclined upper incisors, retrusive upper lip, decreased midface length, and increased maxillary-mandibular difference. Findings of this study showed that patients with a pseudo-Class III malocclusion exhibit certain morphologic, dental, and skeletal characteristics that should be of aid in the diagnosis of pseudo-Class III malocclusion.

Centric Relation↗
PubMed1992

Plate fixation of premaxillomaxillary suture and compensatory midfacial growth changes in the rabbit.

It has been suggested that rigid fixation of the developing craniofacial skeleton may lead to altered craniofacial growth. However, recent experimental studies have shown that microplate fixation of slow-growing calvarial sutures resulted in regional growth disturbances but had little effect on overall craniofacial growth. The present study was designed to assess the effects of microplate fixation of the more rapidly growing facial sutures on compensatory midfacial growth in the rabbit. Twenty-two 1.5-week-old rabbits were randomly divided into 2 groups: sham controls (n = 11) and animals with bilateral premaxillomaxillary suture fixation (n = 11). Fixation was accomplished using an intraoral approach, a 6-mm straight Luhr microplate, and two 2-mm long self-tapping screws across each suture. Serial lateral head radiographs were collected at 1.5, 3.5, 6, 12, and 18 weeks of age. Results revealed that by 3.5 weeks, animals with rigid fixation showed significantly shortened premaxillary lengths (p < 0.05), class III occlusal relationships, decreased midfacial heights, and abnormal palatocranial base angles compared with sham control animals. By 12 weeks of age, "catch-up" growth was evident in most dimensions in animals with fixation compared with shams. Gross examination of the cleaned and dried skulls revealed bony bridging across the premaxillomaxillary suture and osseous fracture lines extending superiorly from the site of screw fixation. Results demonstrated that rigid fixation of a rapidly growing facial suture did not impair long-term midfacial growth in the rabbit model and suggest that compensatory changes may have occurred at fracture lines from the self-tapping screws in these animals.

Adaptation, Physiological↗
PubMed2001

Cleft lip and palate care in the United Kingdom--the Clinical Standards Advisory Group (CSAG) Study. Part 2: dentofacial outcomes and patient satisfaction.

OBJECTIVE: To describe facial development and appearance, quality of bone grafts, oral health, and patient/parent satisfaction, with clinical outcome, for children in two age cohorts born with unilateral cleft lip and palate (UCLP) throughout the United Kingdom. DESIGN: Cross-sectional outcome study. SETTING: Fifty National Health Service cleft centers. PARTICIPANTS: Children born with complete UCLP between April 1, 1982, and March 31, 1984, (12-year-olds) and April 1, 1989, and March 31, 1991 (5-year-olds). Data were collected for 239 5-year-olds and 218 12-year-olds. The parents of these children were also interviewed to determine levels of satisfaction with care received. MAIN OUTCOME MEASURES: Skeletal pattern, dental arch relationship, success of alveolar bone grafting, facial appearance, oral health status, and patient/parent satisfaction. RESULTS: Nearly 40% of 5- and 12-year-olds had poor dental arch relations, and 70% of 12-year-olds had midface retrusion. Fifteen percent of 12-year-olds had not received an alveolar bone graft, and only 58% of bone grafts that had been undertaken were successful. Twenty percent of 12-year-olds and 40% of 5-year-olds had untreated dental caries. Less than one-third of subjects had a good facial appearance as judged by a panel of experts. Levels of patient and parent satisfaction were generally high. CONCLUSION: A rigorous evaluation of cleft care in the United Kingdom reveals disappointing outcomes.

Alveoloplasty↗
PubMed2005

Early assessment of dental arch development in repaired unilateral cleft lip and unilateral cleft lip and palate versus controls.

OBJECTIVE: To evaluate dental arch relationships and dimensions, relative to an age matched noncleft sample, in Caucasian 3-year-old children with repaired unilateral cleft lip (UCL) or unilateral cleft lip and palate (UCLP). DESIGN: Prospective, cross-sectional, case-control study performed in Scotland, U.K. PARTICIPANTS: Eleven children with repaired unilateral cleft lip, 16 children with repaired unilateral cleft lip and palate, and 78 children as controls. MAIN OUTCOME MEASURES: Dental arch relationships and linear arch dimensions. RESULTS: Prevalence of Class III incisor relationship was 31.3% in children with unilateral cleft lip and palate compared with 9.1% in children with unilateral cleft lip. A buccal crossbite was present in 36% of children with unilateral cleft lip, compared with 75.6% of children with unilateral cleft lip and palate.Mean linear maxillary arch dimensions did not differ significantly between children with unilateral cleft lip and the controls. Except for second intermolar width, statistically significant differences existed in mean linear maxillary arch dimensions between the unilateral cleft lip and the unilateral cleft lip and palate groups; the mean linear maxillary arch dimensions were significantly greater in the control group than in the unilateral cleft lip and palate group. The mean cleft-affected anterior quadrant length appeared to be the arch dimension with the greatest power of discrimination among the three groups. There were no significant differences in mean linear mandibular arch dimensions among the three groups. CONCLUSIONS: Anterior crossbite was almost three times more common in the unilateral cleft lip and palate group than in the unilateral cleft lip group. Mean linear maxillary arch dimensions differed significantly between the unilateral cleft lip and palate group and the control group. There were no significant differences in mean linear maxillary arch dimensions between unilateral cleft lip and controls or between mean linear mandibular arch dimensions for unilateral cleft lip, unilateral cleft lip and palate, and controls.

Analysis of Variance↗
PubMedDate not supplied

Craniofacial growth: a three-dimensional soft-tissue study from 6 years to adulthood.

Normal facial growth and development was analyzed through indirect anthropometry in a mixed longitudinal and cross-sectional investigation; 2,023 examinations were performed on 1,156 healthy Caucasian children and adolescents between 6 and 17 years of age and on 191 young adults. Three-dimensional coordinates of 22 facial landmarks were collected with the Three-Dimensional Facial Morphometry method by automated infrared photogrammetry. Selected three-dimensional parameters (linear distances, angles, and a ratio), describing facial height, width, depth, and convexity on the horizontal plane, were calculated and averaged for age and sex. Within each age group, most linear distances were significantly larger in males than in females, with some exceptions in the 11 to 12 age group, where female growth velocity showed a spurt. In females of the 14 to 15 age group the face had almost completed growth; in males of the same age group, a large increase was still to occur to attain adult values. The sexual dimorphism of the parameters calculated did not appear in the different parts of the face to the same extent: a large part of male facial preponderance occurred in the lower third of face. From 6 years of age to adulthood, the soft-tissues in the facial lower third increased by about 23% (males) and 17% (females), in the middle third by about 18% (males) and 13% (females), and in the upper third by about 16% (males) and 9% (females). The male vs. female comparisons within each age group suggested a sexual dimorphism in the timing of soft-tissue facial growth, but an overall similar attainment of different adult dimensions.

Adolescent↗
PubMed1983

Quantitative analysis of the orthodontic and orthopedic effects of maxillary traction.

This article analyzes differences in displacement of ANS and of the upper first molar when different vectors of force are delivered to the maxilla in non-full-banded Phase I mixed-dentition treatment of Class II malocclusion. The sample is identical to that for which we have previously reported differences in change in several key measures of mandibular and facial shape. It includes a cervical-traction group, a high-pull-to-upper-molar group, a modified-activator group, and an untreated Class II control group. Using newly developed computer-conducted procedures, which are described, we have been able to partition the orthodontic and orthopedic components of upper molar displacement and also to isolate treatment effects from those attributable to spontaneous growth and development. In the region of ANS, small but statistically significant and clinically meaningful differences were noted between treatments. When the intercurrent effects of growth and development had been factored out (Table III), orthopedic distal displacement of ANS was significantly greater in the high-pull and cervical groups than in the activator group. Orthopedic downward displacement of ANS was seen to be significantly greater in the cervical group than in the high-pull and activator groups. In the region of the first molar cusp, mean distal displacement of the tooth as an orthopedic effect was found to be almost identical in the cervical and high-pull groups (although variability was greater in the cervical group), but the mean orthodontic effect was significantly greater in the high-pull group than in the cervical group. In the cervical group, where relatively light forces were used for relatively long treatment periods on average, more of the total distal displacement of the upper molar was of an orthopedic character than of an orthodontic character. Conversely, in the high-pull group, in which relatively heavier forces tended to be used for briefer treatment periods, most of the distal displacement at the upper molar was of an orthodontic character. These observations are contrary to expectations from conventional orthodontic theory. In the activator-treated group, roughly equal components of the treatment-associated distal displacement of the upper molar were of the orthodontic and orthopedic types. As concerns changes in the vertical direction in the region of the molar cusp, significant intrusion of both the orthopedic and orthodontic types was seen in the high-pull sample as compared to each of the other groups examined.(ABSTRACT TRUNCATED AT 400 WORDS)

Activator Appliances↗
PubMed2000

Effect of methotrexate on the temporomandibular joint and facial morphology in juvenile rheumatoid arthritis patients.

Juvenile rheumatoid arthritis is a disease characterized by chronic inflammation in one or more joints; it affects children and adolescents up to 18 years of age. This disease may cause significant skeletal joint destruction, and the temporomandibular joint, like other joints, may become severely affected resulting in aberrant mandibular growth, abnormal dentofacial development, and/or altered orofacial muscle function. Methotrexate is the most common remittive agent used in juvenile rheumatoid arthritis to modify the course of inflammatory destruction of peripheral joints. The purpose of this study was: (1) to evaluate the effect of methotrexate therapy on the prevalence of temporomandibular joint lesions and aberration in craniofacial development in children afflicted with juvenile rheumatoid arthritis; (2) to further examine the relationship between the temporomandibular joint/cephalometric findings and rheumatologic data (ie, age at onset, duration of disease); and (3) to evaluate further pauciarticular- and polyarticular-onset disease in juvenile rheumatoid arthritis and the prevalence of temporomandibular joint lesions and facial dysmorphology. The following information was obtained from 45 patients with juvenile rheumatoid arthritis: (1) routine rheumatologic clinical examination data; (2) anamnestic temporomandibular joint evaluation data; (3) clinical temporomandibular joint examination data; (4) lateral cephalometric measurement data; (5) posteroanterior cephalometric measurement data; and (6) individually corrected axial tomographic data. The results demonstrated the following: (1) radiographic evidence of condylar degeneration was apparent in 63% of all patients with juvenile rheumatoid arthritis with pauciarticular patients showing less temporomandibular involvement than polyarticular patients; (2) polyarticular juvenile rheumatoid arthritis patients receiving methotrexate showed less severe temporomandibular joint involvement than the polyarticular patients not receiving methotrexate; (3) the craniofacial structure was affected to a greater extent in the polyarticular form of the disease; (4) the craniomandibular index scores were significantly greater in the polyarticular group; (5) vertical height asymmetry and chin deviation were noted in more than 50% of the patients; and (6) there was a correlation between the severity of condylar lesions and cephalometric findings (ie, mandibular retroposition, posterior rotation, smaller ramus and mandibular dimensions) and the onset and duration of the disease. In conclusion, under the conditions of this study, methotrexate therapy was effective in minimizing temporomandibular joint destruction and craniofacial dysmorphology in juvenile rheumatoid arthritis patients with the polyarticular form of the disease.

Adolescent↗
PubMed1990

[Mandibular movement during chewing-gum chewing on the sagittal plane in children].

The purpose of this study was to investigate the changes of the mandibular movement during chewing-gum chewing in subjects ranging from children with deciduous dentition to adults with permanent dentition, and also to analyze the influences of malocclusion on the mandibular movement in children. The subjects were divided into three groups based on the developing stage of the dentition: ie., i) 7 children; mean age 4.6 yrs-with deciduous dentition, ii) 9 children; mean age 9.0 yrs with mixed dentition and iii) 10 adults; mean age 22.9 yrs with permanent dentition. In addition, 17 subjects who have malocclusion were also examined, who were subdivided into the cross-bite group (mean age 7.9 yrs) and progenia group (mean age 7.3 yrs). The mandibular movements were recorded with Saphon Visi-Trainer CII during chewing-gum chewing and the traces of mandibular movement recorded on the sagittal plane were then analyzed. The results obtained in the present study are summarized as follows; 1) The chewing pattern of children with deciduous dentition was characterized by narrow width and large posterior deviation of the opening and closing pathway. During growth, the width of the pathways increased and their posterior deviation decreased. The narrow width of the opening and closing pathways form the majority of the type of chewing pattern in children with deciduous dentition. On the other hand, the types of reversed and crossed pathways form the majority in adults. 2) The chewing pattern in children with malocclusion was characterized by small posterior deviation in the pathway. The type of reversed cycle was ranked first among the chewing patterns of progenia patients, while there were no significant differences of chewing types between cross-bite patients and children with normal occlusion. As far as the results of the present study is concerned, the changes of the mandibular movement on the sagittal plane following the dentitional growth were characteristic indicated. In addition, malocclusion such as cross-bite and progenia observed in the children may influence the chewing pattern.

Adult↗
PubMed1990

A quantitative assessment of respiratory patterns and their effects on dentofacial development.

The purpose of this study was to assess the effects of quantitatively determined breathing patterns on dentofacial development in growing children. Forty-nine subjects ranging in age from 10 to 16 years participated in the breathing pattern assessment portion of this project. Oral, nasal, and total airflow were measured at separate times by means of a head-out body plethysmograph technique and the values were compared with the subjects' and parents' subjective perceptions of their breathing modes. These breathing pattern measurements also were compared to nasal airway resistance and nasal power. Temporal variation and cyclic respiration, which may play important roles in quantitative evaluations of childrens' breathing patterns, also were addressed. In addition, objective assessments of possible associations between dentofacial structure and respiration were made on 45 of these children. Most subjects' exhibited was either an oronasal or a completely nasal respiratory pattern. However, significant variation in breathing measures was evident among a number of subjects whose breathing was measured twice on the same day and on different days. No significant correlations were found between objectively measured and subjectively determined impressions of respiratory patterns. In addition, there was no association between nasal airway resistance or nasal power and plethysmograph recordings of percent of mouth breathing. Comparisons of measured breathing modes and dentofacial characteristics revealed a weak tendency among mouth breathers toward a Class II skeletal pattern and retroclination of maxillary and mandibular incisors. In contrast, subjective perception of mouth breathing was associated with increased anterior facial height and greater mandibular plane angles. Nasal power and resistance were not correlated with either dental or skeletal variables. This study presents evidence that determination of respiratory pattern is a complex issue for which methods must be refined and performed longitudinally.

Adolescent↗
PubMed1984

Analysis of factors affecting angle ANB.

Cephalometric analyses based on angular and linear measurements have obvious fallacies, which have been discussed in detail by Moyers and Bookstein. However, the clinical application of such an analysis by the orthodontic profession in treatment planning is widely accepted. Variations of angle ANB are commonly used to determine relative jaw relationships in most of the cephalometric evaluations. Several authors, including points A and B influences angle ANB, as does rotational growth of the upper and lower jaws. In addition, the authors point out that growth in a vertical direction (distance N to B) and an increase of the dental height (distance A to B) may contribute to changes in angle ANB. For a Class I relation (Wits = 0 mm), a mathematical formula has been developed which enables the authors to study the geometric influence of angle ANB caused by the following four effects: (1) rotation of the jaws and/or occlusal plane relative to the anterior cranial base; (2) anteroposterior position of N relative to point B, (3) vertical growth (distance N to B); (4) increase in dental height (distance A to B). It was observed that, contrary to the common belief that an ANB angle of 2 +/- 3.0 degrees is considered normal for a skeletal Class I relation, the calculated values of angle ANB will vary widely with changes in these four controlling factors under the same skeletal Class I conditions (Wits = 0 mm). Therefore, in a case under consideration, angle ANB must be corrected for these geometric effects in order to get a proper perspective of the skeletal discrepancy. This is facilitated by comparing the measured ANB angle with the corresponding ANB angle calculated by a formula for a Class I relationship. The corresponding calculated angle ANB can be taken from the tables which are based upon the formula using the same values for SNB, omega (angle between occlusal plane and anterior cranial base), b (which is distance N to B) and a (dental height measured as perpendicular distance A to occlusal plane plus perpendicular distance occlusal plane to B). The difference between actual and calculated angle ANB is a measurement of the severity of the skeletal discrepancy. This leads to a new definition of what denotes skeletal Class II and III relationships, since and angle ANB calculated for a skeletal Class I (Wits = 0 mm) can vary widely and can be either negative or positive.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMedDate not supplied

Chondrogenic differentiation during midfacial development in the mouse: in vivo and in vitro studies.

Because the mouse is now the main model for developmental research of all types, it is important to understand the basic developmental pattern of various organs. The first aim of the present study was to establish normal prenatal developmental standards of the cartilaginous nasal capsule during embryonic development of the mouse. For this purpose we have performed sagittal and coronal sections ranging from E12.5 to E18.5 in gestation age. The primordia of the nasal septal cartilage is recognizable around the 14th embryonic day as demonstrated by the metachromatic toluidine blue staining and by immunostaining of type II collagen. Northern blot analysis of the transcription factors Cart-1 and Sox-9 indicated maximum mRNA levels at E12.5 then a decreased expression during the following days of gestation. Type II collagen and aggrecan mRNA levels are constant during the embryonic period. In the second part of this study, we have established a primary culture system where chondrocytes were isolated from E.18 mouse embryo nasal septum. The purpose of this second part was to assess if chondrocytes could further differentiate in vitro until the hypertrophic phase and matrix mineralization. After the condensation phase, the cells synthesize an extracellular matrix including type II collagen and aggrecan. Progressively, typical cartilaginous nodules composed of clusters of round cells are visible, then increase in size and finally mineralize at day 12 of culture. Cart-1 and Sox-9 mRNA levels remain constant throughout the cultures, whereas type II collagen and aggrecan gradually decrease. Ultrastructural observations of the nodules show typical chondrocytes embedded in a dense network of fibers with matrix vesicles and mineralized foci. Other ultrathin sections revealed the presence of chondrons, typical of hyaline cartilage. Results from this study provide useful tools to further investigate morphogenesis and differentiation of the cartilaginous nasal capsule, and could in the future serve as a basic developmental standard.

Animals↗
PubMed1998

A longitudinal study of the growth and development of the dental arch width from childhood to adolescence in Japanese.

The purpose of this study was to evaluate the longitudinal changes in arch width from childhood to adolescence. The subjects were 28 persons (13 males and 15 females) with untreated normal occlusion. Dental casts were taken at bimonthly intervals from childhood to adolescence. These materials were measured; the changes in the dental arch were compared on the basis of the status of the tooth emergence of certain permanent teeth and also on the chronological age from 3 years to 20 years of age. In the maxilla and mandibula, the width between the deciduous canines, the width between the first deciduous molars, and the width between the second deciduous molars were nearly stable or slightly increased until 6 years of age. After that, all of the deciduous tooth widths gradually increased, especially in the width between the deciduous canine at the emergence of the permanent incisors. The width between the canines decreased until 13 years of age in the maxilla and until 15 years of age in the mandibula. After that, the width between the canines were nearly stable. Until 1 year after emergence, the width between the canines decreased, in particular during the transition to the canines, based on dental age observation. The maxillary first premolar width decreased until 6 months after emergence, based on dental age observation. Thereafter, the width between the maxillary first premolars showed no clear change. The width between the mandibular first premolars, the width between the maxillary second premolars, and the width between the mandibular second premolars increased until about 2-3 years after emergence, but they showed no clear changes thereafter. The width between the maxillary first molars gradually increased until 15 years of age; there was no clear change thereafter. The width between the mandibular first molars was nearly stable throughout the observation period. The width between the maxillary second molars decreased until 2 years after emergence; no clear change was observed thereafter. The width between the mandibular second molars was unstable until after about 2-3 years after emergence and then became nearly stable.

Adolescent↗