Biomedical subjects

S Kreiborg

Publications and source records attributed to S Kreiborg.

At least 19 recordsLinked to original sources

PubMed2006

Early postnatal development of the mandible in children with isolated cleft palate and children with nonsyndromic Robin sequence.

OBJECTIVE: Analysis of early postnatal mandibular size and growth velocity in children with untreated isolated cleft palate (ICP), nonsyndromic Robin sequence (RS), and a control group of children with unilateral incomplete cleft lip (UICL). MATERIAL: 114 children (66 isolated cleft palate, 7 Robin sequence, 41 unilateral incomplete cleft lip) drawn from a group representing all Danish cleft children born from 1976 through 1981. All children were examined at both 2 and 22 months of age. METHODS: Cephalometric x-rays and maxillary plaster casts. Mandibular length and height were measured and mandibular growth velocity (mm/year) was calculated. Cleft width was measured on the casts at 2 months of age. RESULTS: Mean mandibular length and posterior height were significantly smaller in isolated cleft palate and Robin sequence, compared with unilateral incomplete cleft lip. Mandibular length in Robin sequence was also significantly shorter, compared with isolated cleft palate. No significant difference was found between mean mandibular growth velocities in the three groups. No significant correlation was found between mandibular length and cleft width in either isolated cleft palate or Robin sequence at 2 months of age. CONCLUSION: The children with isolated cleft palate and Robin sequence had small mandibles shortly after birth, but with a relatively normal growth potential. No true mandibular catch-up growth was found up to 22 months of age in either group. No significant correlation was found between mandibular size and cleft width in either group at 2 months of age. However, there was a significant trend toward the shorter the mandible, the more severe the sagittal extension of the cleft.

Age Distribution↗

PubMed2005

Delineation of an interstitial 9q22 deletion in basal cell nevus syndrome.

Basal cell nevus syndrome (Gorlin syndrome) is an autosomal dominant disorder characterized by the presence of multiple basal cell carcinomas (BCC), odontogenic keratocysts, palmoplantar pits, and calcification in the falx cerebri caused by mutational inactivation of the PTCH gene. In few cases, the syndrome is due to a microdeletion at 9q22. Using high-resolution chromosome analysis we have identified a patient with the karyotype, 46,XY,del(9)(q21.3q31) de novo. He had typical clinical features consistent with basal cell nevus syndrome, but also additional features likely to be caused by loss of additional chromosomal material in this region. The deletion breakpoints were characterized with fluorescence in situ hybridization (FISH) analysis using BAC clones. The 15 Mb long deletion includes 87 RefSeq genes including PTCH. Hemizygosity of one or more genes might contribute to the additional symptoms observed in this patient.

Adult↗

PubMed2005

Three-dimensional analysis of mandibular growth and tooth eruption.

Normal and abnormal jaw growth and tooth eruption are topics of great importance for several dental and medical disciplines. Thus far, clinical studies on these topics have used two-dimensional (2D) radiographic techniques. The purpose of the present study was to analyse normal mandibular growth and tooth eruption in three dimensions based on computer tomography (CT) scans, extending the principles of mandibular growth analysis proposed by Björk in 1969 from two to three dimensions. As longitudinal CT data from normal children are not available (for ethical reasons), CT data from children with Apert syndrome were employed, because it has been shown that the mandible in Apert syndrome is unaffected by the malformation, and these children often have several craniofacial CT scans performed during childhood for planning of cranial and midface surgery and for follow-up after surgery. A total of 49 datasets from ten children with Apert syndrome were available for study. The number of datasets from each individual ranged from three to seven. The first CT scan in each of the ten series was carried out before 1 year of age, and the ages for the 49 scans ranged from 1 week to 14.5 years. The mandible and the teeth were segmented and iso-surfaces generated. Landmarks were placed on the surface of the mandible, along the mandibular canals, the inner contour of the cortical plate at the lower border of the symphysis menti, and on the teeth. Superimposition of the mandibles in the longitudinal series was performed using the symphysis menti and the mandibular canals as suggested by Björk. The study supported the findings of stability of the symphysis menti and the mandibular canals as seen in profile view previously reported by Björk & Skieller in 1983. However, the mandibular canals were, actually, relocated laterally during growth. Furthermore, the position of tooth buds remained relatively stable inside the jaw until root formation started. Eruption paths of canines and premolars were vertical, whereas molars erupted in a lingual direction. The 3D method would seem to offer new insight into jaw growth and tooth eruption, but further studies are needed.

Acrocephalosyndactylia↗

PubMed2005

Novel mutation of the initiation codon of PAX9 causes oligodontia.

Tooth development is under strict genetic control. Oligodontia is defined as the congenital absence of 6 or more permanent teeth, excluding the third molar. The occurrence of non-syndromic oligodontia is poorly understood, but in recent years several cases have been described where a single gene mutation is associated with oligodontia. Several studies have shown that MSX1 and PAX9 play a role in early tooth development. We screened one family with non-syndromic oligodontia for mutations in MSX1 and PAX9. The pedigree showed an autosomal-dominant pattern of inheritance. Direct sequencing and restriction enzyme analysis revealed a novel heterozygous A to G transition mutation in the AUG initiation codon of PAX9 in exon 1 in the affected members of the family. This is the first mutation found in the initiation codon of PAX9, and we suggest that it causes haploinsufficiency.

Adolescent↗

PubMed2004

Early craniofacial morphology and growth in children with bilateral complete cleft lip and palate.

PURPOSE: Analysis of craniofacial morphology and growth in children with bilateral complete cleft lip and palate (BCCLP), compared with a control group with unilateral incomplete cleft lip (UICL), before any treatment as well as 20 months after lip closure. MATERIAL: The children were drawn from a group representing all Danish children with cleft born 1976 to 1981. Sixty-four children were included in the study (19 BCCLP and 45 UICL). The ages were 2 and 22 months at examinations 1 and 2, respectively. METHOD: The method of investigation was infant cephalometry in three projections. The craniofacial morphology was analyzed using linear, angular, and area variables. Growth was defined as the displacement vector from the coordinate of the corresponding landmark in the x-ray at examination 1 to its coordinate at examination 2, corrected for x-ray magnification. The growth of an anatomical region in a patient was assessed by investigating the growth pattern formed by a collection of individual growth vectors in that region. RESULTS: The BCCLP group differed significantly from the UICL group. The most striking findings in BCCLP were an extremely protruding premaxilla; markedly increased posterior maxillary width; increased width of the nasal cavity; short maxilla with reduced posterior height; short mandible; bimaxillary retrognathia; severe reduction in the size of the pharyngeal airway; and a more vertical facial growth pattern. CONCLUSION: Our findings indicate that a facial type including a wide and posterior short maxilla, short mandible, and bimaxillary retrognathia might be a liability factor that increases the probability of developing cleft lip and palate.

Case-Control Studies↗

PubMed2003

Early craniofacial morphology and growth in children with nonsyndromic Robin Sequence.

PURPOSE: Craniofacial morphology and growth comparisons in children with untreated nonsyndromic Robin Sequence (RS) and a control group with unilateral incomplete cleft lip (UICL) in which the lip was surgically closed at 2 months of age. MATERIAL: The 52 children (7 RS and 45 UICL) included in the study were drawn from a group representing all Danish cleft children born 1976 through 1981. The ages of the children were 2 and 22 months at the time of examination 1 and 2, respectively. METHOD: The method of investigation was three-projection cephalometry. Craniofacial morphology was analyzed by means of linear, angular, and area variables. Growth at a specific anatomical location in a patient was defined as the displacement vector from the coordinate of the corresponding landmark at examination 1 to its coordinate at examination 2. RESULTS: The most striking findings in the RS group were markedly increased posterior maxillary width, increased width of the nasal cavity, short maxilla with reduced posterior height, short mandible, bimaxillary retrognathia, and severe reduction in size of the pharyngeal airway. The amount of facial growth was similar in the two groups; however, a tendency toward a more vertical growth direction was observed in the RS group. CONCLUSION: Facial morphology in children with RS differed significantly from that of children with UICL at both 2 and 22 months of age. The magnitude of facial growth was similar in the two groups, whereas a tendency toward a more vertical facial growth direction was observed in the RS group.

Cephalometry↗

PubMed2003

Craniofacial morphology and growth comparisons in children with Robin Sequence, isolated cleft palate, and unilateral complete cleft lip and palate.

OBJECTIVE: Comparison of early craniofacial morphology and growth in children with nonsyndromic Robin Sequence (RS), isolated cleft palate (ICP), and unilateral complete cleft lip and palate (UCCLP). SUBJECTS: One hundred eight children with cleft: 7 with RS, 53 with ICP, and 48 with UCCLP were included in the study. The children were drawn from the group of all Danish children with cleft born 1976 through 1981. METHOD: Three-projection infant cephalometry. RESULTS: The craniofacial morphology in the RS, ICP, and UCCLP groups had some common characteristics: a wide maxilla with decreased length and posterior height, wide nasal cavity, short mandible, bimaxillary retrognathia, and reduced pharyngeal airway. The shortest mandible was found in RS followed by ICP and UCCLP; the pharyngeal airway was reduced in RS and ICP, compared with UCCLP; and the maxillary complex and nasal cavity were wider in UCCLP than in the other groups. The amount of facial growth in all three groups was similar; however, the direction was more vertical in UCCLP than in RS and ICP. CONCLUSION: Except for a shorter RS mandible, the facial morphology of infants with RS and ICP was similar, as was the amount of facial growth and the growth pattern. The differences in facial morphology can be ascribed to the difference in the primary anomaly. The amount of facial growth was similar in the three groups; however, the growth pattern showed a more vertical direction in UCCLP than in RS and ICP. It is hypothesized that the mandibular retrognathia in RS represents the outer end of that of the ICP distribution.

Analysis of Variance↗

PubMed2002

A three-dimensional method of visualizing the temporomandibular joint based on magnetic resonance imaging in a case of juvenile chronic arthritis.

AIM: The purpose of this study was to present a new visualizing method for temporomandibular joint (TMJ) pathology in 3D at several condylar positions and to apply the method to a case of juvenile chronic arthritis (JCA) with previously diagnosed bilateral TMJ disorder and to a subject without signs and symptoms from the TMJ. SUBJECT: The 20-year-old female patient had suffered from polyarticular JCA from the age of 6 years 8 months. The present study is based on a follow-up examination after the completion of orthodontic treatment with the Herbst appliance. Both TMJs were examined using magnetic resonance imaging (MRI) at closed and open mouth positions. The mandibular condyle, the glenoid fossa and the articular disc were segmented and 3D reconstruction of these structures was carried out. RESULTS: The condyle was characterized by an increased sagittal diameter with osteophyte-like formation at the anterior aspect of the condylar head and flattening of the superior surface. The depth of the glenoid fossa was reduced and the articular eminence was remarkably flat. The articular disc was markedly diminished and posteriorly placed on the condylar head. The distance of the condylar path during mouth opening was reduced and the curvature of the condylar path was quite flat. The disc moved slightly posteriorly on the condylar head and remained in the glenoid fossa during mouth opening. CONCLUSION: The imaging modality described improves visualization of TMJ morphology and gains insight into the TMJ pathology of the JCA patient, adding to understanding of the clinical problems.

Adult↗

PubMed2002

Human masticatory muscle volume and zygomatico-mandibular form in adults with mandibular prognathism.

Although several investigators have reported associations between masticatory muscles and skeletal craniofacial form, there is no agreement on the association. We tested the hypothesis that masticatory muscle volume correlates with the size and form of the adjacent local skeletal sites. For this purpose, we investigated the morphological association of the cross-sectional area and volume of temporal and masseter muscles with zygomatico-mandibular skeletal structures using computerized tomography (CT) in 25 male adults with mandibular prognathism. Muscle variables significantly correlated with widths of the bizygomatic arch and temporal fossa but not with the cranium width. Masseter volume significantly correlated with cross-sectional areas of the zygomatic arch and mandibular ramus. Masseter orientation was almost perpendicular to the zygomatic arch and mandibular antegonial region. The zygomatic arch angle significantly correlated with the antegonial angle. The results of the study suggest that the masticatory muscles exert influence on the adjacent local skeletal sites.

Adolescent↗

PubMed2002

Early craniofacial morphology and growth in children with unoperated isolated cleft palate.

OBJECTIVE: Analysis of craniofacial morphology and growth in children with untreated isolated cleft palate (ICP) (cleft of the secondary palate only) at 2 and 22 months of age and comparison of the morphology and growth to that of a control group with unilateral incomplete cleft lip (UICL). MATERIAL AND METHODS: A total of 98 cleft children (53 with ICP and 45 with UICL) drawn from a larger group representing all Danish children with cleft born in the period 1976 to 1981 were included in the study. Craniofacial morphology and growth were analyzed using three-projection infant cephalometry. RESULTS: The ICP group differed significantly from the UICL group. The most striking findings in the ICP group were: short maxilla; reduced posterior maxillary height; increased posterior maxillary width (in the 2-month-old); short mandible; reduced posterior height of the mandible; bimaxillary retrognathia; and reduced pharyngeal depth, height, and area. The facial growth pattern was fairly similar in the two groups except for a somewhat more vertical growth direction in the ICP group. CONCLUSION: The facial morphology in ICP children differs significantly from that of children with UICL of the same age. The differences in facial morphology can be ascribed to the difference in the primary anomaly in the ICP group. The facial growth pattern was fairly similar in the ICP and UICL group; however, a somewhat more vertical growth direction was observed in the ICP group.

Body Height↗

PubMed2001

Mutations in the gene encoding c-Abl-binding protein SH3BP2 cause cherubism.

Cherubism (MIM 118400) is an autosomal dominant inherited syndrome characterized by excessive bone degradation of the upper and lower jaws followed by development of fibrous tissue masses, which causes a characteristic facial swelling. Here we describe seven mutations in the SH3-binding protein SH3BP2 (MIM 602104) on chromosome 4p16.3 that cause cherubism.

Adaptor Proteins, Signal Transducing↗

PubMed2001

Orofacial pain, jaw function, and temporomandibular disorders in women with a history of juvenile chronic arthritis or persistent juvenile chronic arthritis.

OBJECTIVES: We sought to study the long-term outcome of juvenile chronic arthritis (JCA) in the temporomandibular joint (TMJ). STUDY DESIGN: Temporomandibular disorders, including TMJ involvement, were assessed in 42 women with pauciarticular or polyarticular JCA--on average 25.8 years from disease onset--and compared with those found in matched control subjects. Disease-related parameters associated with temporomandibular disorders were identified. RESULTS: The TMJ was involved in 66.7% of the patients, most severely in extended pauciarticular JCA. Temporomandibular disorders were more frequent in the patients than in the control subjects, especially in those with persistent disease. The TMJ involvement was positively correlated with disease duration and negatively correlated with jaw opening and occlusal support. Duration of active JCA and history of functional pain were identified as predictors of present TMJ involvement. CONCLUSION: In a long-term follow-up, TMJ involvement proved frequent in the studied patients and was associated with long disease duration and previous pain on jaw opening. The findings suggest that patients with JCA should undergo orofacial evaluation on a regular basis.

Adult↗

PubMed2001

A method for three-projection infant cephalometry.

OBJECTIVE: To assess morphology and growth in infants and children with craniofacial anomalies based on comprehensive digitization of radiographic films in three, mutually orthogonal projections. METHOD: The method consists of (1) acquisition of radiographic films in a highly standardized three-projection (lateral, frontal, and axial) cephalometer, (2) marking and digitization of a total of 279 anatomical landmarks in the three projections, and (3) computation and presentation (tabular and graphical) of 356 linear and angular variables describing the craniofacial morphology, including soft tissue. Computation of statistical entities describing a patient, a group of patients, the differences between patients or groups of patients was carried out. Error assessment of the method involved investigation of error distribution among a number of error sources. Duplicate digitization of radiographic films from 30 randomly selected patients, and from 10 dry skulls, was carried out to determine the errors contributed by the procedure of landmark digitization and the distribution of error among landmarks and variables, as well as between projections. RESULTS: The average error due to landmark digitization, s(i), determined by duplicate digitization and calculated by use of Dahlberg's formula was 0.8 mm for linear variables and 1.6 degrees for angular variables. CONCLUSION: This method of infant cephalometry has been shown to be highly accurate and reproducible, and it adds significant new potential for, e.g., asymmetry detection, population comparison, and growth measurements compared to other cephalometric techniques due to its standardized acquisition and digitization protocol, inclusion of an axial projection, and the large number of well-defined landmarks and variables involved.

Cephalometry↗

PubMed2000

Quantification of osseous facial dysmorphology in untreated unilateral coronal synostosis.

Unilateral coronal synostosis results in dysmorphology of the midface in addition to well-characterized cranial and orbital deformities. Because most American infants with this problem have undergone cranio-orbital surgery within their first year of life for the past 25 years, a paucity of data exist regarding the natural history of untreated unilateral coronal synostosis. In an attempt to remedy this void, an international search was conducted to identify computed tomography data sets of living individuals with untreated unilateral coronal synostosis; data were obtained from two European centers and one center in the United States. Results limited to the study of the midface are presented here. Digital data from high-resolution head computed tomography scans of 11 living, white individuals with untreated unilateral coronal synostosis were obtained from three craniofacial centers (in Denmark, The Netherlands, and the United States). Image volumes were constructed from each scan using ANALYZE biomedical imaging software. Fourteen pairs of three-dimensional distances were calculated on the ipsilateral (the side of the synostosis) and the contralateral (the side opposite to the synostosis) hemifaces using 11 osseous landmarks. The resulting measurements were expressed as a ratio of the ipsilateral: contralateral sides. Descriptive statistics were derived for the untreated unilateral coronal synostosis population and compared with analogous measurements performed on dried skulls. Age at computed tomography ranged from 1.1 to 21.1 years (mean, 6.6 years; median, 4.1 years). Twelve of the 14 measured distances differed by greater than 5 percent on the ipsilateral side, and all but one of these measurements were decreased on the ipsilateral side when compared with contralateral values. The results of this study support the following conclusions: (1) There are discrete and measurable differences in the facial morphology between patients with untreated unilateral coronal synostosis and normal skulls. (2) Intercenter and international collaboration can provide a sufficient number of individuals with rare craniofacial anomalies to quantitatively determine group characteristics. (3) Quantitative documentation of rare anomaly natural history is necessary for quantitative outcome assessment of treated patients.

Adolescent↗

PubMed2000

Surface-bounded growth modeling applied to human mandibles.

From a set of longitudinal three-dimensional scans of the same anatomical structure, we have accurately modeled the temporal shape and size changes using a linear shape model. On a total of 31 computed tomography scans of the mandible from six patients, 14,851 semilandmarks are found automatically using shape features and a new algorithm called geometry-constrained diffusion. The semilandmarks are mapped into Procrustes space. Principal component analysis extracts a one-dimensional subspace, which is used to construct a linear growth model. The worst case mean modeling error in a cross validation study is 3.7 mm.

Anthropometry↗

PubMed2000

Craniofacial comparisons in 22-month-old lip-operated children with unilateral complete cleft lip and palate and unilateral incomplete cleft lip.

OBJECTIVE: The objective of the study was to analyze the craniofacial morphology in infants with unilateral complete cleft lip and palate (UCCLP) in which the lip and the anterior part of the palate had been surgically closed at 2 months of age and to compare the morphology with that of a control group with unilateral incomplete cleft lip (UICL) in which the lip had also been surgically closed at 2 months of age. DESIGN: The sample consisted of a total of 108 cleft children all fulfilling the entry criteria, besides diagnosis, as follows: The child was of Danish origin; the age of the child was between 650 and 750 days (approximately 22 months) at the time of examination; the child was healthy except for its single cleft malformation; the surgical procedure in each group had been performed at about 2 months of age by the same surgeon. The surgical methods used were a Tennison procedure (UICL group) and a Tennison procedure supplemented by palatovomer plasty (UCCLP group). METHODS: The method of investigation was infant cephalometry in the lateral, frontal, and axial projections. Linear, angular, and area variables describing the craniofacial morphology were calculated and supplemented by mean plots from the cephalometric projections in the two groups. RESULTS AND CONCLUSIONS: Statistical analysis based on Student's t test showed that the facial morphology in the 22-month-old UCCLP group differed significantly from that of the UICL group. The most pronounced differences were found in the maxillary complex and the mandible. The deviations observed in the UCCLP group at 22 months of age were similar to those previously observed at 2 months of age. However, several of the dysmorphic traits had become less pronounced; some had remained the same; and a few had become worse with time.

Anthropometry↗

PubMed1999

External and internal macromorphology in 3D-reconstructed maxillary molars using computerized X-ray microtomography.

AIM: The aim of this study was to perform a qualitative analysis of the relationship between the external and internal macromorphology of the root complex and to use fractal dimension analysis to determine the correlation between the shape of the outer surface of the root and the shape of the root canal. METHODOLOGY: On the basis of X-ray computed transaxial microtomography, a qualitative and quantitative analysis of the external and internal macromorphology of the root complex in permanent maxillary molars was performed using well-defined macromorphological variables and fractal dimension analysis. Five maxillary molars were placed between a microfocus X-ray tube with a focal spot size of 0.07 mm, a Thomson-SCF image intensifier, and a CCD camera compromising a detector for the tomograph. Between 100 and 240 tomographic 2D slices were made of each tooth. Assembling slices for 3D volume was carried out with subsequent median noise filtering. Segmentation into enamel, dentine and pulp space was achieved through thresholding followed by morphological filtering. Surface representations were then constructed. A useful visualization of the tooth was created by making the dental hard tissues transparent and the pulp chamber and root-canal system opaque. On this basis it became possible to assess the relationship between the external and internal macromorphology of the crown and root complex. RESULTS: There was strong agreement between the number, position and cross-section of the root canals and the number, position and degree of manifestation of the root complex macrostructures. Data from a fractal dimension analysis also showed a high correlation between the shape of the root canals and the corresponding roots. CONCLUSIONS: It is suggested that these types of 3D volumes constitute a platform for preclinical training in fundamental endodontic procedures.

Anatomy, Cross-Sectional↗

PubMed1999

Drying and rewetting anterior crown fragments prior to bonding.

Fractured anterior teeth can be restored by adhesive bonding of the fragment to the remaining tooth structure. This in vitro study describes the effect on fracture strength of fragments dried and rewetted for various periods of time prior to bonding. Seventy central incisors from sheep were fractured. The resulting incisal crown fragments were then stored in air at room temperature at ambient humidity (70 +/- 16%) for 5 s, 30 min, 1 h, 3 h, 6 h, 12 h, or 24 h. The apical parts of the fractured teeth were stored in water. After storage in air each fragment was then bonded to the matching apical tooth structure with a bonding agent and a low-viscosity composite resin. After water storage for 2 days, mean fracture strength was measured. Another group of teeth comprising 40 sheep central incisors was fractured and the fragments were stored in air at room temperature for 24 h as above. The fragments were then immersed in water for 10 min, 1 h, 1 day, or 7 days, prior to bonding and measurement as described above. Statistical analysis revealed that the fracture strength of the fragment-bonded teeth was unaffected by air storage of the fragment for up to 1 h prior to bonding, after which additional drying resulted in decreased fracture strength. Fragments dried for 24 h in air and rewetted by immersion in water for at least 1 day were fragment-bonded without loss of fracture strength.

Analysis of Variance↗