Linkage analysis of candidate regions in Swedish nonsyndromic cleft lip with or without cleft palate families.

OBJECTIVE: To analyze linkage of five candidate regions for nonsyndromic cleft lip with or without palate (CLP) on chromosome 2p13, 4q, 6p23, and 19q13; in addition chromosome 1q32, the locus for van der Woude syndrome, on Swedish CLP families. DESIGN: Three to five linked microsatellite markers were selected from each candidate region. Polymerase chain reaction (PCR) with fluorescent-labeled microsatellite markers was performed on DNA samples from the participating families. Electrophoresis of the PCR products was performed on a laser-fluorescent DNA sequencer. The genotype data were analyzed with multipoint linkage analysis. Modes of inheritance tested included two autosomal dominant, an autosomal recessive, and a nonparametric model. Multipoint logarithm of odds (LOD) scores were also calculated by assuming genetic heterogeneity. PARTICIPANTS: Nineteen Swedish multigenerational families with at least two first-degree relatives affected with CLP. Greater than 50% of the families studied show vertical transmission of the clefting phenotype and both inter- and intrafamilial variability were noted. RESULTS: Cumulative multipoint LOD scores for the whole group of families calculated under autosomal dominant modes of inheritance were negative in all regions and less than -2 except chromosome 6p23. LOD scores calculated under recessive inheritance and the nonparametric model were inconclusive. There was no significant evidence of genetic heterogeneity among the sample group. CONCLUSIONS: The group of Swedish CLP families did not demonstrate significant linkage to any of the five candidate regions examined. This might suggest a new but yet unknown CLP locus or loci in this family group. However, because linkage could not be excluded in some individual families, they should still be tested with candidate genes from these regions.

Facial profile and dental changes before, during and after treatment with Hansaplate/Headgear.

In this prospective study the changes of facial profile and dentition in 19 boys and 19 girls treated for 1 year with Hansaplate/Headgear were analyzed yearly over a 4-year period. On average the boys were 10.2 and the girls 9.2 years old at the first recording, i.e., 1 year pretreatment. The actual values are compared with standard growth data presented by Bathia and Leighton (1993). Irrespective of the initial face morphology, the Hansaplate/Headgear appliance straightened the facial hard and soft tissue profiles favorably. The upper lip became more retruded while the lower lip was unaffected by therapy. During the 2-year post-treatment period these changes continued, probably as a consequence of growth. The overjet was reduced by 5 mm during treatment and was found to be quite stable 2 years after treatment.

Clinical and genetic studies of Van der Woude syndrome in Sweden.

Van der Woude syndrome (VWS) is an autosomal dominant craniofacial disorder characterized by pits of the lower lip, hypodontia and cleft lip and/or cleft palate. It has been reported as the most common form of syndromic orofacial clefting with very high penetrance and varied expressivity. The disease locus for VWS has been mapped to chomosome 1q32, but the gene is yet to be cloned. Here we report a total of 11 Swedish VWS patients: 9 familial cases from two families and two isolated cases. Clinical examination of these patients showed phenotypic variability, even between patients from the same family. Genetic studies were performed using four microsatellite markers from chromosome 1q32. Constitutional deletion in this region was not demonstrated in any of the familial or isolated cases. However, in the two VWS families, linkage analysis using these markers showed positive LOD (logarithm of the odds) scores ranging from 2.56 to 2.88 to all individual markers. The highest LOD score of 3.75 was obtained with the combined haplotypes of D1S491 and D1S205, thus confirming linkage of VWS in these two families to 1q32. We conclude that there is varied expressivity but no evidence of genetic heterogeneity in VWS.

Orthodontic application of color image addition to visualize differences between sequential radiographs.

A new technique was developed making it possible to visualize changes that take place after premolar transplantation. Three sequential radiographs from a series of standardized control examinations were digitized and registered to the first radiograph in the series using subtraction technique. The digitized radiographs were then transformed into monochromatic images: red, blue, and green. After correction of gray level and contrast, the three radiographs were superimposed. All details that were common in the radiographs were then displayed in black-and-white. Details that were different appeared in color. Red and blue combines into magenta, blue and green into cyan, and green and red into yellow. A procedure was developed to create color-coded radiographs according to the above. The procedure was applied to cases that had been treated by premolar transplantation. The color coding offers the possibility to identify any radiographic changes that take place over time, eg, growth, apposition or resorption of bone, and progression or regression of pathological processes.

Craniofacial morphology in Chinese and Swedish children with Angle Class I and Class II occlusal relations.

The purpose of this study was to compare the craniofacial morphology of a group of Chinese children from northern China with a group of Swedish children. Each ethnic group comprised 20 boys and 20 girls with Class I occlusion, and 20 boys and 20 girls with Class II occlusion. The ages of the children ranged from eight to ten years. Lateral cephalometric radiographs were used for the recording of a number of skeletal, dental, nasopharyngeal airway, and hyoid bone variables. The results of the comparisons of the two ethnic groups showed that the antero-posterior dimensions of the anterior cranial base and the maxilla in the Chinese children were significantly smaller than the corresponding dimensions in the Swedish children. The mean values of anterior and posterior face heights, inclination of the upper incisors, and protrusion of the lower incisors, were significantly greater in the Chinese than in the Swedish samples. In the median plane, the size of the nasopharyngeal airway was significantly greater in the Chinese than in the Swedes. This difference was due to the fact that the soft tissues covering the posterior nasopharyngeal wall were thinner in the Chinese children than in the Swedish children. In general, the ethnic differences were the same in the Class I and the Class II groups. The differences in some of the dental and skeletal characteristics found between northern Chinese and Caucasian-children are similar to previously described differences between southern Chinese and Caucasian children.

Evaluation of facial features in two groups of cleft lip and palate patients receiving centralized and non-centralized treatment regimes.

The aims of the present study were: (a) to evaluate facial profile and other findings in a group of cleft lip and palate (CLP) patients receiving centralized services as compared with a group of patients who received non-centralized services and who were not submitted to bone grafting procedures; and (b) to evaluate and compare the outcome of early bone grafting procedures that were included in the centralized treatment regime to the outcome of a non-centralized treatment approach that did not include bone grafting procedures. Forty-three lateral cephalometric radiographs of CLP Greek Caucasian children not receiving centralized treatment and 43 lateral cephalometric radiographs of CLP Swedish Caucasian children receiving centralized treatment, strictly matched for age, sex, and type of cleft, were compared as a total and in two subgroups, according to age. Differences were also evaluated in the unilateral (UCLP) and in the bilateral (BCLP) groups separately, as well as in groups discriminated by age, i.e. in the patients born before 1984 (age 11-19 years) and in those born after 1984 (age 4-10 years), as 1984 was the year when early bone grafting was discontinued in the Stockholm area. The findings of this study revealed the following. The overall difference in facial and dental cephalometric findings between CLP children receiving a centralized treatment approach as compared with those treated without centralization was significant. The Swedish group showed a trend towards better cephalometric values throughout all the age groups. When the early age groups were compared, the early bone grafting procedure that was included in the centralized treatment regime did not seem to be a positive factor, in comparison with the absence of bone grafting in the non-centralized treatment regime.

Treatment of adolescents with Hansaplate/headgear. Influence on face in profile and on dentition.

The treatment effects of Hansaplate/headgear in the course of 1 year were analyzed. Twenty-one girls and 19 boys, 10 and 11 years old, respectively, with postnormal occlusion and an average overjet of 8 mm, made up the treatment group. Forty untreated patients with the same type of malocclusion and dentofacial morphology as the treated children, and paired and matched for sex and age, made up the controls. Measurements were obtained from cephalometric headfilms. Matched-intrapairs analysis of control versus treatment changes after 1 year of treatment was done. This showed that the treatment resulted in inhibited sagittal growth of the maxilla, increased anterior face height and a flattened soft tissue profile with a less protrusive upper lip and a less pronounced sulcus mentolabialis. The overjet decreased by 5 mm on average. Only slight retroclination of the upper incisors without extrusion and retroclination of lower incisors to the mandibular plane occurred. No significant anterior positioning of the mandible as compared with the controls was recorded in this study.

Normalization of incisor position after adenoidectomy.

Changes in incisor inclination and position in both jaws of children during the first 5 years after adenoidectomy were studied. The main change is a significant increased labial inclination of the incisors for the adenoidectomy groups. All variables that measure the labiolingual position of the mandibular incisors confirm a significant labial incisor positioning for both sexes. Stepwise regression analysis shows that 41% to 44% of the incisor proclination after adenoidectomy is accounted for by two regressors--sex (female) and increase in the sagittal size of the nasopharynx. The study supports the hypothesis that a changed mode of breathing after adenoidectomy is associated with significant labial positioning of the incisor teeth.

Mandibular and maxillary growth after changed mode of breathing.

The amount of maxillary and mandibular growth and the direction of maxillary growth were studied in 38 children during the 5 years after adenoidectomy for correction of severe nasopharyngeal obstruction. The amount of mandibular growth measured between successive gnathion points on superimposed radiographs was significantly greater in the group who had an adenoidectomy than in the matched controls. In the boys the difference was 3.8 mm (p less than 0.001), and in the girls the difference was 2.5 mm (p less than 0.01). The boys also showed a tendency toward greater growth in the maxilla as measured between successive subnasal points (1.2 mm, p less than 0.05). We detected no difference in the direction of maxillary growth between who had undergone adenoidectomy and the controls.

Orthodontic and surgical treatment of unilateral condylar hyperplasia during growth--a case report.

A 9-year-old boy was diagnosed as having an unilateral cross-bite with mandibular deviation. This was later found to be due to unilateral hyperplasia of the right condyle. The increased growth activity subsequently led to an extreme facial asymmetry and a serious psychological condition began to develop. Consequently, surgery was performed at the age of 11 years 8 months when removal of the enlarged condyle and an oblique ramus osteotomy on the opposite side was performed. In this way the facial asymmetry was eliminated. No effort during the surgery was made, however, to restore normal occlusion. The post-operative orthodontic treatment was successful in allowing growth to bring about a normalization of the occlusal relationships. Two years after surgery, complete aesthetic and function rehabilitation has been achieved. This has also led to an improvement in the patient's psychological condition. The result was still stable 11 years post-operatively. The case illustrates the value of early treatment and co-operation between orthodontists and oral surgeons.

A morphometric study of bone surfaces and skin reactions after stimulation with static magnetic fields in rats.

The present investigation was undertaken to measure any bone surface changes after stimulation with orthodontic magnets and, furthermore, to examine the soft tissue in immediate contact with the magnets. Both distal parts of the tibial hind legs in six groups of young rats were fitted with devices holding two orthodontic magnets in the experimental legs and similar devices without magnets in the control legs. The animals were killed after 2, 3, and 4 weeks. Morphometric evaluation showed significant increases in resorbing areas after 3 and 4 weeks. Similarly, a reduction was evident in the number of epithelial cells under the areas where the magnets had been applied. These findings indicate that the stimulation of bone resorption in the present study may have been caused by inhibition of the bone-lining osteoblasts. This proposition is supported by the apparent inhibitory effect of the magnetic fields on epithelial recycling that was seen as a reduced thickness of the epithelium under the magnets. Consequently, static magnetic fields should be used with care in orthodontic practice until a more complete understanding of their mechanism of action has been established.

Early interceptive treatment of asymmetry.

Severe asymmetry in pre-adolescent children usually arises either from congenital anomalies, such as unilateral condylar hypoplasia, or as a result of juvenile rheumatoid arthritis, condylar hyperplasia or early fracture of the mandible. Early surgical and orthodontic interceptive treatment of the asymmetry is important for normal development of the face and jaws.

Relationship between mandibular incisor crowding and nasal mucosal swelling.

In this study, cephalometric and dental cast variables relating to 30 male and 20 female children, 8 to 13 years old with chronic nasal mucosal swelling, were compared with those relating to age- and sex-method controls. These controls were orthodontically untreated subjects with no histories of airway obstruction. The children with chronic nasal mucosal swelling had been referred because of chronic difficulties with nasal breathing to the Department of Otolaryngology Airflow Laboratory at the Hospital for Sick Children in Toronto. Previously active posterior rhinomanometry with a head-out volume displacement plethysmograph had been used to measure nasal resistance in 1000 consecutive subjects. Participants in the study reported here were selected from subjects whose nasal resistance fell markedly following administration of a decongestant spray. The subjects selected were found to have significantly (p less than 0.001) more mandibular incisor crowding, significantly (p less than 0.01) smaller mandibular arch widths than the controls, and significantly (p less than 0.001) smaller maxillary arch widths than the controls. The male subjects had significantly (p less than 0.01) smaller mandibular arch widths than the male controls.

Titanium implant anchorage in orthodontic treatment an experimental investigation in monkeys.

Tooth loss can be a problem when orthodontic appliances have to be stabilized for treatment. It has been shown that endosseous titanium implants are well integrated during treatment of edentulous patients with intra-osseous anchored bridges. In the present investigation titanium implants were inserted immediately after tooth extraction. After tissue-integration of the implants they were successfully used for anchorage when orthodontic treatment was performed. In a clinical situation the implants may simultaneously be used for reconstruction of the bite.

Posture of the head, the hyoid bone, and the tongue in children with and without enlarged tonsils.

The purpose of this investigation was to analyse whether there were any differences between children with and without enlarged tonsils with regard to the posture of the head, the hyoid bone, and the tongue. Twenty-two children with enlarged tonsils were compared with a matched normal control group. Of the children in the tonsil group, 59 per cent were mouth-breathers during the day and 82 per cent during the night. None of the control children was a mouth-breather. The results showed that, compared with the control children, children with enlarged tonsils had an extended posture of the head, a lowered position of the hyoid bone, and an antero-inferior posture of the tongue. The vertical position of the hyoid bone also reflected the vertical position of the tongue. The antero-posterior position of the tongue was closely related to the oro-pharyngeal depth. The postural pattern in children with enlarged tonsils appears to be associated with the need for maintenance of free oro-pharyngeal airway capacity.

Cranio-facial morphology in children with and without enlarged tonsils.

The purpose of the present study was to compare the cranio-facial morphology in children with and without enlarged tonsils. The material consisted of 73 children with enlarged tonsils, and a control group of children with normal tonsils, matched for age, sex, and number. The mean age for the groups was 10.1 and 10.0 years, respectively. Evaluation of anamnestic history, clinical examination, and lateral skull radiographs were undertaken. Compared to the control children, the children with enlarged tonsils had more retrognathic and posteriorly inclined mandibles, larger anterior total and lower facial heights, and larger mandibular plane angles. Regression analyses revealed that functional, postural, and morphological factors, such as open mouth posture, low posture of the tongue, large depth of oropharynx at the site of the tonsils as well as mouth-breathing at night, were associated with skeletal features expressing an increased open vertical configuration and mandibular retrognathism.

Dentition in children with enlarged tonsils compared to control children.

The aim of the present study was to evaluate whether or not there are any differences in the dentition between children with enlarged tonsils and those with normal tonsils. A sample of 73 children (33 boys and 40 girls) with enlarged tonsils and with a mean age of 10.1 years was compared with a normal control group, matched for age and sex. Eighteen dentition variables and thirty-two variables in anamnestic, clinical, pharyngeal and postural findings were recorded. Measurements were obtained from lateral skull radiographs and dental casts. Group means were compared. Relationships between variables were studied using simple correlations and multiple stepwise regression analyses. It was found that children with enlarged tonsils had more retroclined lower incisors, more anteriorly positioned upper incisors, smaller overbite, larger overjet, shorter lower dental arches, narrower upper dental arches and an increased frequency of lateral crossbite. Functional and/or morphological disorders, causing an open posture of the mouth, a lowered anterior posture of the tongue and a low position of the hyoid bone are thought to be associated with the differences in the dentition between the two groups. Obstruction of the oropharynx by enlarged tonsils, might be one factor responsible for these dysfunctions.

Mandibular form and position related to changed mode of breathing--a five-year longitudinal study.

A five-year follow-up study was performed on 26 children treated for nasal obstruction by adenoidectomy, who exhibited a changed mode of breathing postoperatively. They were compared with a control group matched according to age and sex. Lateral skull radiographs were used to examine mandibular morphology. The mandibular outline was registered using 36 digitized points. This method of portraying growth changes provides a valuable complement to isolated measurements. The technique revealed a more anterior direction of symphyseal growth in the adenoidectomy group following surgery as well as some reversal of the initial tendency to a posterior rotation of the mandible.