Five year follow-up of mandibular distraction osteogenesis on the dentofacial structures of syndromic children.

OBJECTIVES: To determine long-term treatment outcomes of mandibular distraction osteogenesis (DO) in syndromic children with severely hypoplastic lower jaws. DESIGN: Descriptive clinical study. SETTING AND SAMPLE POPULATION: Cleft Palate and Craniofacial Centre, Department of Plastic Surgery, Helsinki University Central Hospital. Ten children (mean age 7.6 years) with various syndromes (craniofacial microsomia, Treacher Collins syndrome, Nager syndrome). SUBJECTS AND METHODS: Ten growing children with severely retrognathic lower jaws were distracted with an extraoral bicortically fixed DO device (mean, 34 days) followed by a consolidation period (mean, 9 weeks). Orthodontic treatment was performed pre- and/or postoperatively with fixed or functional appliances (mean 14 months). OUTCOME MEASURE: The landmarks on standard lateral cephalometric X-rays were digitized and angular and linear measurements were compared using Student's t-test to assess changes in pre-distraction, post-distraction, post-consolidation and 1 year follow-up. Long-term follow-up (2 and 5 years) was interpreted according to mean values. RESULTS: The measurements of SNB, ANB, facial convexity angle, overjet and overbite, and soft tissue facial profile showed significant correction of the mandibular retrognathia and malocclusion. The mandibular divergence decreased and mandibular, corpus, and ramus lengths remained stable during the consolidation period. The regression of mandibular measurements towards pre-distraction values was observed in skeletal and dental parameters and soft tissue profiles during the first postoperative year and continued during the 2- to 5-year follow-up period. The achieved mandibular corpus and ramus lengthening was stable while the mandible displayed considerable posterior rotation but no further growth. Orthodontic treatment could not overcome the regression of mandibular measurements to their original values. The maxilla continued its normal growth during the long-term follow-up. Two patients had tracheostomies, but the tube was removed from both during or immediately after distraction. CONCLUSION - Excellent short-term structural results of mandibular DO are not stable during the growth of syndromic children because of restricted mandibular growth. Thus, a re-evaluation of DO timing in the improvement of facial aesthetics must be considered. However, mandibular DO in children with severe airway problems is recommended.

Effect of mandibular distraction osteogenesis on developing molars.

OBJECTIVE: To observe the effect of mandibular distraction osteogenesis (DO) on developing molars. DESIGN: Descriptive clinical study. SETTING: University hospital setting. Seventeen children (mean age 7.6 years) with various syndromes (hemifacial/craniofacial microsomia, Goldenhar syndrome, Treacher Collins syndrome, Nager syndrome and Pyle-Bakwin-Krida syndrome) participated. experimental variable - Severely retrognathic lower jaws were distracted (mean 30 days) with an extraoral bicortically fixed DO device. OUTCOME MEASURE: Consecutive panoramic tomograms were analysed after a mean follow-up period of 3.6 years, range 1-6.9 years. RESULTS: The mandibular molars were affected by DO in 13 of the 17 patients which included 18 of 63 mandibular molars studied. Structural changes included root malformations, hindered tooth development and the destruction of tooth follicles. Positional changes such as shifted and tilted teeth were also found. Three injured teeth failed to erupt. These changes were because of splitting of the tooth follicle during the osteotomy (22%), piercing of the tooth follicle by the pin (39%) or migration of tooth germ towards the newly created bone (39%). Fifteen per cent of first molars, 43% of second molars and 31% of third molars were affected during the distraction process. Of all dental injuries, 44% were noticed while the appliance was in place. A further 17% of injuries were noted between 3 months and 1 year postoperatively and 33% during the second postoperative year. CONCLUSIONS: Although dental injuries are a minor disadvantage compared with the vast benefits offered by DO, focusing on these drawbacks might lead to re-consideration of the type of the device as well as the timing of DO.

Craniofacial cephalometric morphology in children with CATCH 22 syndrome.

OBJECTIVES: To evaluate cephalometrically the craniofacial, pharyngeal and cervical morphology in children with CATCH 22, and to compare and quantify the findings with age- and sex-matched controls. DESIGN: A retrospective case-control study. SETTING AND SAMPLE POPULATION: Forty-one children (20 girls) with CATCH 22 were compared with age- and sex-matched controls from lateral cephalograms taken at the mean age of 8.5 years (range 5.8-12.9). The deletion of 22q11 was verified by fluorescence in situ hybridization techniques. Thirteen of the children with CATCH 22 had palatal clefts. OUTCOME MEASURE: Linear and angular measurements were obtained from lateral cephalograms. A Student's t-test and a paired Student's t-test were used in the statistical analysis. Standard deviation scores (SDS) were calculated to quantify the variation. RESULTS: Children with CATCH 22 had obtuse cranial base angles and long anterior cranial bases. Their faces were long with increased facial convexity. The maxillae were long but both jaws were retrognathic and the lower jaws posteriorly diverged. The pharynges were wide in the nasopharyngeal area and narrow in the hypopharyngeal area. The development of the hyoid bones was delayed, and hyoid bone and atlas lengths were reduced. The morphology of the children with CATCH 22 with and without a palatal cleft was similar. Despite several statistically significant differences between the children with CATCH 22 and the controls, the SDS did not exceed +/-2 for any of the measurements. CONCLUSION: Children with CATCH 22 have several minor distinctive morphological features in the craniofacial, pharyngeal, and cervical areas.

Reduction in head size in patients with aspartylglucosaminuria.

OBJECTIVE: To show that the head may shrink in adult patients with aspartylglucosaminuria (AGU), a neurodegenerative disease. METHOD: The head circumference (HC) of 40 adult patients (age at baseline 15 to 47) was measured twice with an interval of 10 years. Of these 40, 21 aged 15-47 and 19 young patients aged 5-14 as well as 40 healthy controls underwent lateral cephalometric radiography. RESULTS: During 10 years' follow-up, the HC of 26 (65%) had decreased by 1 to 4.5 cm (mean 1.7, P < 0.001). Evaluation of lateral skull radiographs revealed that patients aged 15 or more had significantly thicker skulls than did younger patients (P = 0.015). Mean intracranial length (glabella-opisthocranium) of the patients aged 15 or more was significantly shorter than in patients aged 14 years or less (P = 0.029). These measurements indicated that brain volume had decreased. CONCLUSIONS: Macrocephalia in childhood followed by reduced brain volume in adulthood is evident in patients with AGU and is reflected by a decrease in head size.

Microvascular temporomandibular joint and mandibular ramus reconstruction in hemifacial microsomia.

Microvascular temporomandibular joint (TMJ) and mandibular ramus reconstruction was performed in a 4-year-old hemifacial microsomia patient with multiple craniofacial and extracranial anomalies (Goldenhar syndrome). Her major craniofacial anomalies included bilateral cleft lip and palate, left macrostomia, left microtia, and complete absence of the left vertical mandibular ramus and TMJ. Most of her other anomalies had been corrected surgically before TMJ and vertical mandibular ramus reconstruction, which was accomplished with a metatarsophalangeal (MTP) joint transplantation. The MTP joint was placed in hyperextended position in the skull base inserting the proximal phalanx under the remnants of the zygomatic arch and replacing the vertical mandibular ramus with the metatarsal bone. Straight mouth opening, correction of the midline, and normalized lateral movements of the mandible were accomplished. The graft includes two epiphyseal plates, which should maintain growth of the transplant. During the follow-up period (16 months) the achieved results have been maintained without adverse effects. The present technique appears to be a promising alternative in the treatment of children with Pruzansky type 3 hemifacial microsomia.

Craniofacial features in Cohen syndrome: an anthropometric and cephalometric analysis of 14 patients.

Cohen syndrome (Mendelian Inheritance in Man [MIM] no. 216550) is a rare, autosomal-recessive inherited disorder with mental retardation and a typical appearance. The condition is relatively common in Finland where 35 patients have been diagnosed. We studied 22 patients in detail, obtaining anthropometric measurements of the head and face, and cephalometric radiographs of 14 patients (14-57 years of age). Measurements of patients were compared to population norms and matched controls. Anthropometric analysis confirmed and quantified the previously described syndrome features: small head size [-4 standard deviations (SD)], with varying cephalic index. Width of the upper face was close to normal, but width of the lower face was small. Philtrum length was shorter than in healthy controls (p = 0.0039 in females and p = 0.0014 in males). The measurements from standardized radiographs revealed short cranial base dimensions (-2.2 and -2.6 SD), but normal cranial base angles. Prognathism of jaws was within normal limits. Reduced head size (microcephaly), short philtrum and small cranial base dimensions are essential features in Cohen syndrome. In addition, most patients had forward-inclined upper incisors and maxillary prognathia. We conclude that exact measurements mostly confirmed the Cohen syndrome description based previously on clinical impression.

Vector control in lower jaw distraction osteogenesis using an extra-oral multidirectional device.

PURPOSE: This cephalometric study describes structural changes in facial features and occlusion during distraction of the mandible. PATIENTS: Seven patients aged 7-16 years with severely retrognathic lower jaws were treated by bilateral extra-oral distraction. The direction of the distraction was changed during the distraction period (mean 30 days) using the adjustable hinge in the distractor. Cephalometric follow-up documents were analysed for changes in facial and occlusal structures. The distraction therapy proceeded in two phases. First, horizontal distraction was undertaken to achieve a good incisor relationship. After this, the direction was changed to a more vertical plane with the use of a hinge axis, and the tips of the lower incisors were used as the axis of rotation. RESULTS: The most remarkable changes were in the more anterior position of the lower jaw, the increase in ramus height and good dental overjet. The mandibular occlusal plane became more horizontal, creating a posterior open bite. By guiding the vector of distraction, no anterior open bite or lateral crossbite appeared. CONCLUSION: This study points out the advantages of using extra-oral multidimensional distractors. Severe lower jaw deficiency requires not only a long working length of the device but also precise control of the vector during the active phase of distraction.

Comparisons of speech aerodynamics and lateral craniofacial cephalometrics in cleft lip and palate patients with and without Finnish /r/-sound distortion.

To study the associations between the articulation of the Finnish /r/ sound and dentofacial and pharyngeal lateral cephalometric morphology and speech physiology, 18 (12 females, 6 males) young adult cleft patients' /r/ sound was analysed auditorily by 3 speech experts. Laryngeal resistance (LARE), the smallest nasal cross-sectional area (NASA), nasal resistance (NASAR) and velopharyngeal orifice area (VEPA) were measured with pressure flow technique, and 31 points were identified from the lateral cephalograms to landmark the skeletal structure, pharyngeal airway diameters, and position of the hyoid bone. The present results showed no significant differences in lateral cephalometric skeletal, nasopharyngeal, oropharyngeal or hypopharyngeal morphology between subjects with and without /r/-sound distortion. There were no significant correlations either between /r/ distortions and NASA, NASAR or VEPA. An anteriorly positioned hyoid bone was significantly associated with decreased LARE and /r/ distortion. LARE was significantly lower in subjects with /r/ distortion.

Orthopedic cervical headgear with an expanded inner bow in class II correction.

Forty consecutively referred children, 20 boys and 20 girls, with a Class II division I malocclusion and protrusive maxilla were treated with orthopedic cervical headgear with a 10 mm expanded inner bow and a long outer bow bent 15 degrees upwards. The mean age of the children at the beginning of treatment was 9.3 years (SD 1.3, range 6.6 to 12.4 years), and the average treatment time was 1.8 years (SD 0.6, range 0.8 to 3.1 years). In all patients Class II molar relationships were successfully corrected to Class I molar relationships. This was accompanied by a marked widening of both maxillary and mandibular dental arches. The cephalometric analysis suggested that the observed improvement of the occlusion was due to an inhibition of forward growth of the maxilla and anterior downward rotation of the palate.

Development of trunk asymmetry in a cohort of children ages 11 to 22 years.

STUDY DESIGN: A cohort study with a follow-up period of 11 years. OBJECTIVES: To study the growth of the spine with a focus on the development of trunk asymmetry and scoliosis. SUMMARY OF BACKGROUND DATA: Trunk asymmetry, a common phenomenon at adolescence, can be considered the clinical expression of scoliosis. The importance of the pubertal growth spurt has been stressed in the natural history of scoliosis. However, no cohort studies have focused on the ascending and descending phase of the spine's peak growth and the development of trunk asymmetry. METHODS: The cohort consisted of all the fourth-grade school children in the Western school district of Helsinki, Finland, in the spring of 1986. These 1060 children (515 girls and 545 boys), from the average age of 11 to 14 years, were invited to undergo annual examinations. The 855 children (80.7%) who had participated in the study at the age of 14 years were invited to a reexamination at the age of 22 years. This invitation was accepted by 430 (208 women and 222 men; 54%) of those invited. The forward bending test, the spinal pantography, and the anthropometric measurements were carried out by the same author (M.N.) throughout this study. RESULTS: At 22 years of age, 30% of the adults were found to be symmetric, with a hump less than 4 mm in the forward bending test, whereas 51% had a hump of 4 to 9 mm, and 19% had a hump 10 mm or larger (major asymmetry). The directional asymmetry of trunk surface, a skew to the right at the thoracic level and to the left at the lumbar level at puberty, remained constant at adult age. The prevalence of major trunk asymmetry at adult age was the same in both women and men, in contrast to the female predominance at puberty in this cohort. There were close correlations in the degrees of thoracic and lumbar asymmetry between puberty and adult ages. CONCLUSIONS: The shape of the back develops mainly during the pubertal growth spurt at ages 12 to 14 years in girls and boys. Trunk asymmetry (and mild scoliosis) seems as prevalent in young adult women as in men, although at puberty idiopathic scoliosis was twice as prevalent among girls as among boys in this cohort.

Associations between thoracic kyphosis, head posture, and craniofacial morphology in young adults.

The aim of the present study was to investigate associations between thoracic hyper- and hypokyphosis, head posture, and craniofacial morphology in young adults. Using forward bending test and spinal pantographic measurements, 31 subjects, 16 with thoracic hyper- and 15 with hypokyphosis, were selected from a population-based cohort of 430 young adults. Lateral roentgen-cephalograms were taken in natural head posture and craniofacial and postural angular measurements were calculated. Any statistically significant differences between the groups thoracic hyperkyphosis and thoracic hypokyphosis--were analysed using Student's t test. Subjects with thoracic hyperkyphosis had a larger atlantocervical angle (At/ CVT, P < 0.01) than subjects with thoracic hypokyphosis. However, head position (NSL/VER) was similar in both groups, probably owing to the visual perception control of craniovertical relation. There was no statistically significant difference in craniofacial morphologyy between the groups.

Comparison between cephalometric classification methods for sagittal jaw relationships.

The present study evaluated how 2 widely used cephalometric sagittal analyses, ANB angle and WITS appraisal, classify skeletal classes I, II, and III in a random selection of 497 Finnish boys aged 4-20 years. This distribution was also compared with the visual inspection of cephalometric structures judged by 2 university instructors in orthodontics. The results showed remarkable differences and even sparked controversy concerning classification of the sagittal jaw relationships. The ANB angle and the WITS appraisal emphasized the role of class II based on a failure to distinguish the proportion of class I. The low-angle influence skewed the distribution of the ANB pattern in the class III direction, and the WITS pattern, conversely, towards class II. High- or low-angle influence had only minor effects on the visual inspection of cephalometric structures. This cross-sectional study showed an age-related decreasing mean value for the ANB angle and increasing mean value for the WITS appraisal, thus explaining the remarkable difference in the distribution of sagittal classes. However, the findings of age-related changes makes the use of the fixed norms questionable. For extreme or controversial cephalometric interpretations, visual inspection provides an essential aid in diagnosis and skeletal classification.

The cellular origin of fibronectin in the basement membrane zone of developing tooth.

The cellular source of fibronectin in the dental epitheliomesenchymal interface was studied in interspecies combinations of mouse and quail tissue. Species-specific fibronectin antibodies were produced by immunizing rabbits with purified mouse or chicken fibronectin and by absorbing both antisera with purified heterologous fibronectin and insoluble tissue extract. The absorbed antisera to mouse and chicken fibronectin showed fluorescent staining only in mouse and chicken tissue sections, respectively, but not vice versa. When the mouse mesenchymal dental papilla was combined and cultured either with the mouse enamel organ or with the quail pharyngeal epithelium, mesenchymal cell differentiation was initiated and typical alignment of mesenchymal cells along the basement membrane was seen. Examination with transmission electron microscope revealed a typical bilaminar basal lamina with adherent fibrillar matrix on its mesenchymal aspect. Immunofluorescent localization of fibronectin with the mouse-specific fibronectin antiserum showed a brilliant staining in the mesenchymal tissue and in the basement membrane zone. When the chicken-specific fibronectin antiserum was used, no staining was detected in either tissue recombinations. We have suggested earlier that fibronectin in the dental basement membrane plays an important role during the differentiation of mesenchymal cells into odontoblasts. The present study demonstrates that fibronectin in the basement membrane of the developing tooth is produced exclusively by the differentiating mesenchymal cells.

Autoradiographic visualization of glycoproteins and glycosaminoglycans in the epithelio-mesenchymal interface of developing mouse tooth germ.

The turnover of basement membrane macromolecules during tooth morphogenesis and odontoblast differentiation was examined by light microscopic autoradiography using 3H-fucose, 35S-sulfate and 3H-glucosamine. Marked incorporation into the basement membrane was found throughout the progressive development. Pulse-chase experiments and prelabeling of tissue components indicated that glycoproteins and glycosaminoglycans in the dental basement membrane are mainly derived from the enamel epithelium. During odontoblast differentiation, incorporation was increased at the epitheliomesenchymal interface at the site of differentiating mesenchymal cells. From these sites the label also disappeared rapidly. This suggests that the active remodeling of extracellular matrix is related to odontoblast differentiation.

Diazo-oxo-norleucine (DON)-induced alterations in the extracellular matrix of the mouse tooth germ.

In a previous study we have shown that the glutamine analogue diazo-oxo-norleucine (DON) inhibits the differentiation of mesenchymal cells into odontoblasts in the developing tooth. In the present study we have studied the effect of DON on the formation of the extracellular matrix by using light microscopic autoradiography and transmission electron microscopy. The inhibition of odontoblast differentiation was accompanied by alterations in the extracellular matrix at the epithelio-mesenchymal interface. The interface was reduced in space and filled with filamentous material, and the organization of collagen fibers in more advanced tooth germs was disturbed. DON also reduced the incorporation of [35S]sulphate into the basement membrane region, whereas no marked change was observed in the incorporation of [3H]fucose. These results suggest that DON affected the cell--matrix interaction which is believed to control the differentiation of odontoblast.

Ultrastructure of the epithelial-mesenchymal interface in the mouse tooth germ.

The structure of the epithelial-mesenchymal interface of a developing mouse embryonic tooth germ was examined at the time of cell differentiation by using transmission and scanning electron microscopy. During odontoblast differentiation, the basal lamina was continuous beneath the inner enamel epithelium, and the fibrils at the mesenchymal aspect increased in density and length. Numerous cell processes of the preodontoblasts were seen in close contact with the basal lamina. This supports the idea that the basement membrane is involved in the differentiation of mesenchymal cells into odontoblasts, probably by providing special attachment sites for the aligning mesenchymal cells. The rearrangement of intracellular organelles in the cells of enamel epithelium and a change of epithelial morphology were already seen at the time of the initial predentin secretion by odontoblasts. At this time, the basal lamina was still present. The penetration of epithelial microvilli into the epithelial-mesenchymal interface through breaks in the basal lamina related to the onset of predentin mineralization. This suggests that the determination of epithelial cells into ameloblasts already occurs before the disappearance of the basal lamina.