Biomedical subjects

H Kjellberg

Publications and source records attributed to H Kjellberg.

13 recordsLinked to original sources

PubMed2003

Craniofacial morphology and dental age in children with Silver-Russell syndrome.

OBJECTIVES: This investigation is a part of a multidisciplinary descriptive evaluation of the Silver-Russell syndrome (SRS). The aim of this study was to describe the craniofacial morphology, occlusion and dental age in children with the SRS. DESIGN: A descriptive literature-controlled study. SETTING AND SAMPLE POPULATION: Sixteen children diagnosed as having SRS, 10 boys and six girls, aged 4.4-14.5 years, were referred from different parts of Sweden to the Queen Silvia Children's Hospital, Göteborg University. EXPERIMENTAL VARIABLE: Facial morphology was measured on lateral and postero-anterior radiographs. Occlusion, tooth eruption and palatal height were measured on casts, and dental maturity was evaluated on orthopantomograms. OUTCOME MEASURE: Linear and angular measurements were obtained from lateral radiographs and the ratios of the linear measurements from the postero-anterior radiographs. The degree of tooth calcification shown on orthopantomograms was taken as a measure of dental maturity. Biometric measurements were taken and the degree of tooth eruption was recorded from the dental casts. The SRS children were compared with reference groups with t-test and z-scores. RESULTS: Overall, SRS children were found to have smaller linear facial dimensions and deviations in the facial proportions, such as a small retropositioned, and steeply inclined maxilla and mandible, and a proportionally larger anterior facial height in relation to the posterior facial height. In 40% of them a smaller facial height or length on one side (facial asymmetry) was correlated to the smaller side of the body. The frequency of malocclusions was higher, and the palatal height showed a tendency towards an increase. Dental maturity was within normal limits, while the time of tooth eruption was slightly delayed. CONCLUSIONS: The deviating facial morphology described above is a part of the syndrome, which is characterized by short stature, growth hormone deficiency and asymmetries of the body. The higher percentage of malocclusions in the SRS children might lead to a greater need of orthodontic treatment.

Abnormalities, Multiple↗

PubMed2000

Craniofacial morphology, dental occlusion, tooth eruption, and dental maturity in boys of short stature with or without growth hormone deficiency.

The aim of this project was to study the craniofacial morphology, dental occlusion, dental maturation and tooth eruption in short-statured boys with growth hormone secretion ranging from low to high. The measurements from lateral and posteroanterior cephalograms, orthopantomograms and plaster models were used. Almost all linear measurements of the facial structures were significantly smaller. A disproportionate growth in the cranial base structures as well as in the jaws resulted in facial retrognathia, a proportionately smaller posterior than anterior facial height, and a steep vertical inclination of the mandible. Dental crowding was more common and the overbite was small. Dental maturity and tooth eruption were delayed 1.2 and 1.3 yr, respectively. No significant differences between the idiopathic short-statured and the growth hormone-deficient group in any of the above-mentioned variables were found. It can be concluded that although most of the cephalometric variables measured differed significantly from the average, the facial appearance of the boys is not conspicuous and is of minor clinical importance. However, the short-statured boys might be in greater need of orthodontic treatment due to the higher percentage of dental crowding.

Adolescent↗

PubMed2000

Changes in masticatory mandibular movements in growing individuals: a six-year follow-up.

The pattern of mandibular movement during chewing is influenced by several central and peripheral factors. The aim of the present study was to determine whether changes in masticatory function, characterized by mandibular velocity and displacement, occurred during individuals' normal growth. Forty-seven children, 9-15 years of age, were followed over a 6-year period. All had an Angle Class I occlusion with no obvious orthodontic problems. Oral motor function with respect to mandibular displacement, duration, and velocity was monitored 3-dimensionally with an opto-electronic method. The chewing cycle was divided into an opening, closing, and occlusal phase. Total body height was measured. During the follow-up period, all masticatory variables except the 3-dimensional opening distance showed significant changes. The total chewing cycle duration, the opening and occlusal time of the chewing cycle, and the 3-dimensional closing distance increased during the growth period, while the closing time of the chewing cycle, the 2-dimensional lateral and vertical distances and both the opening and closing velocity decreased. The children who grew proportionally most in height during the 6-year period, i.e. the youngest children in the group studied, showed a significantly larger decrease in the opening velocity. From this study it becomes evident that the variables of the chewing cycle undergo a continuous process of change during growth. This is possibly a reflection of anatomical changes, maturation of the central nervous system, and altered functional demands.

Adolescent↗

PubMed1999

Effect of low masticatory function on condylar growth: a morphometric study in the rat.

The aim of this study was to estimate the influence of functional alterations on the size of the mandibular condyle and to elucidate in detail, by means of histomorphometric analysis, the effect of changing the consistency of the diet on different portions of the condylar cartilage in growing rats. Forty growing rats were randomly divided into 2 groups. One group received the normal hard diet for rats; the other group received a standardized soft diet. The experimental period was 28 days. Ten animals from each group were used for gross morphometric analysis; the other 10 animals were used for histologic analysis of the condyle. The morphometric analysis of the condylar cartilage was based on the 25th, 50th, and 75th percentiles of the mediolateral sections of the condyles. The sections were divided into 3 parts: the anterior, intermediate, and posterior part; 4 measurements were performed in each. Significant differences were found in the condylar length and width between the groups, the soft diet group having a smaller condyle. The histomorphometric analysis of cartilage thickness showed significant differences between the 2 groups, being thinner in the anterior part and thicker in the posterior part of the condyle in the soft diet group. These routine histologic findings cannot explain the gross morphologic differences in the condylar size between the groups; this means that increased condylar cartilage thickness is not necessarily evidence of increased condylar growth. The results from this study indicate that a low masticatory function leads to decreased growth of the condyle and changes in the thickness of the cartilage. This may be the effect of an alteration in the stress distribution in the temporomandibular joint area, because of the absence of large masticatory forces.

Animals↗

PubMed1998

Craniofacial growth in juvenile chronic arthritis.

The craniofacial growth in children with juvenile chronic arthritis (JCA), especially that of the mandible, and the degree of destruction of the mandibular condyles vary depending on the heterogeneity in duration and intensity of the disease. In JCA children showing destruction of the temporomandibular joint, the dentofacial morphology is characterized by overall smaller dimensions of the mandible, mandibular retrognathia, a steep mandibular plane, Class II malocclusion, dental crowding, and frontal open bite. In children with unilateral condylar destruction, asymmetries will develop, with the chin deviating to the affected side. The facial morphology of JCA children with condylar lesions becomes more abnormal during growth, reflecting a decelerated mandibular development and a backward-rotating growth pattern. The main single cause of the deviating craniofacial growth is mandibular condylar destruction. Other factors that may influence the craniofacial growth are head posture, soft tissue stretching, disease activity and drug therapy, type of onset of the disease, muscle weakness, decreased functional ability, and orthodontic treatment.

Arthritis, Juvenile↗

PubMed1995

Craniofacial structure in children with juvenile chronic arthritis (JCA) compared with healthy children with ideal or postnormal occlusion.

The aim of the present study was to evaluate the influence of condylar destruction on the craniofacial growth of children with juvenile chronic arthritis (JCA) and to compare their craniofacial structure with that of healthy children with ideal or postnormal occlusion. Thirty-five children (7 to 16 years) affected by JCA were compared with 136 children (7 to 16 years) with normal facial structure and occlusion (ideal group) and 62 children (7 to 12 years) with postnormal occlusion (postnormal group). Panoramic radiographs and lateral cephalograms were taken to detect condylar lesions and analyze facial structure. Multiple regression analysis was applied to test the possible relationships between the groups. The present study largely confirms earlier findings that the JCA group has a characteristic craniofacial structure. Their structure differed not only from the facial characteristics of children with ideal, but also to some extent, from children with postnormal occlusion. Furthermore, the craniofacial structure of children with JCA varied greatly, and radiographs showed that the most extreme craniofacial changes, particularly the mandibular structure, were associated with condylar lesions. In conclusion, the arthritic condylar lesions seem to be the main etiologic reason for the altered facial structure and changes in the occlusion in children with JCA. Influences of other factors, such as masticatory muscular function, are also discussed.

Adolescent↗

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↗

PubMed1995

Bite force and temporomandibular disorder in juvenile chronic arthritis.

The aim of this study was to investigate the functional condition of the stomatognathic system in children suffering from juvenile chronic arthritis, with respect to bite force and temporomandibular disorder in relation to radiographic abnormalities of the mandibular condyle, occlusal factors and systemic disease parameters. Thirty-five children with juvenile chronic arthritis were compared to 89 healthy children with an Angle Class I occlusion and 62 children with an Angle Class II malocclusion. Subjective symptoms and clinical signs of temporomandibular disorder and radiographic mandibular condylar changes were more common in children with juvenile chronic arthritis than in the two comparison groups. Maximal molar and incisal bite forces and maximal molar bite force endurance times were also significantly reduced in children with juvenile chronic arthritis. It is concluded that the differences between the groups are caused mainly by the systemic inflammatory disease itself, but a functional influence of weakened masticatory muscles cannot be excluded.

Adolescent↗

PubMed1995

Characteristics of masticatory movements and velocity in children with juvenile chronic arthritis.

Oral motor function (mandibular displacement and velocity) in individuals with juvenile chronic arthritis was studied by using an optoelectronic method. The children were compared with two asymptomatic groups: one group with Class I occlusion and the other with Class II malocclusion. The results showed that children with juvenile chronic arthritis and condylar lesions had reduced lateral mandibular masticatory movements. In children with Class II malocclusion, a longer three-dimensional closing distance and a slower closing velocity were found. In children with both juvenile chronic arthritis and Class II malocclusion, an interaction between juvenile chronic arthritis and malocclusion resulted in a longer occlusal time, a shorter amplitude, and a slower velocity. It can be concluded that juvenile chronic arthritis and Class II malocclusion, per se, might have minor influences on the chewing characteristics, but the two factors seem to interact, resulting in an altered masticatory pattern. A possible explanation is that children with juvenile chronic arthritis have an increased risk of developing a Class II malocclusion because of the growth disturbances sequelae of condylar lesions. The alteration in occlusion, together with restricted movements in the arthritic condyle, may be the underlying reasons for the findings.

Adolescent↗

PubMed1995

Juvenile chronic arthritis. Dentofacial morphology, growth, mandibular function and orthodontic treatment.

In children with Juvenile Chronic arthritis (JCA), temporomandibular joint involvement may lead to disturbances in dentofacial growth and mandibular function. The aim of this thesis was to study the dentofacial morphology, temporomandibular joint destruction and mandibular function in JCA children, and the relation between these factors. The intention was also to make a longitudinal study of the changes in facial morphology during growth and during treatment with functional appliances. Thirty-five JCA children, 12 boys and 23 girls, aged 7-16 years (mean 11.2 years), and the control groups, with either normal or distal occlusion, were studied by means of panoramic radiographs, lateral cephalograms, study casts, recordings of signs and symptoms of temporomandibular disorders (TMD), bite force and chewing characteristics. A method to evaluate the condylar height on panoramic radiographs was developed. Panoramic radiographs are found to be reliable for evaluation of the condylar height, provided the same panoramic machine is used. The dentofacial morphology in JCA children is characterized by a smaller, more retrognathic and steeper inclined mandible compared to that of healthy children with ideal occlusion. Compared to healthy children with distal occlusion, no difference in mandibular retrognathia could be demonstrated but the JCA children showed a smaller, more steeply inclined mandible. The presence and extent of condylar lesions play a significant role in the development of the facial morphology and also contribute to the facial heterogeneity among JCA children. During growth the JCA children without radiographically visible condylar lesions showed a growth pattern resembling that of healthy children with normal occlusion, while children with condylar lesions showed aggravation of the mandibular retrognathia and a tendency towards a backward-rotating growth pattern. The chewing movements in JCA children are restricted by the disease and by the presence of condylar lesions. In JCA children with distal occlusion, interaction between both factors (JCA and malocclusion) resulted in further alterations of the chewing movements and chewing velocity. Subjective signs and clinical symptoms of TMD are more frequently found in JCA children, some of which are significantly correlated to radiographic changes in the condyle. The bite force and the endurance time are about half of that of healthy children. A low molar bite force is significantly correlated to a low mouth-opening capacity. The orthodontic treatment with functional appliances resulted in improvement in the dental malocclusion, while the skeletal effects were of minor magnitude in both the JCA children and in healthy children with distal occlusion.(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent↗

PubMed1994

Condylar height on panoramic radiographs. A methodologic study with a clinical application.

The aim of this study was to develop and apply a reliable method of measuring the effects of condylar lesions quantitatively on panoramic radiographs. Three different types of machines were tested. Two dry skulls were exposed in six positions in each machine, and the relative size of the condyle in relation to ramus height was calculated. The results showed good validity for the reference points used. The head position did not contribute to the variation in the measurements, but the type of panoramic machine had some influence. It was concluded that the method may be applied when calculating condylar ratios, provided that the same panoramic machine is used. The relative height of the condyle in relation to ramus height was measured bilaterally in three groups of children, with either normal or postnormal occlusion or with juvenile chronic arthritis (JCA), to detect possible asymmetries and define differences in the relative condylar height. The JCA group had a significantly shorter relative condylar height, and asymmetries were commoner than in the other two groups.

Adolescent↗

PubMed1993

The relationship between maximal bite force, bite force endurance, and facial morphology during growth. A cross-sectional study.

The aims of this investigation were to study the relation between facial morphology and bite force at different ages during growth and to investigate possible relations between bite force and the variables age, finger force, stature, and sex in growing healthy individuals. One hundred and thirty-six individuals were included, consisting of six groups of males and females, 7-9, 10-12, and 20-24 years old. Standardized photographs were taken to determine the facial type. The occlusal relationship, body height, finger force, maximal bite force, and bite force endurance amplitude were recorded. All bite force variables and finger force increased with age in both sexes. A positive correlation was found between the maximal bite force in the incisor region and the ratio of upper to lower facial height; this is, subjects with a high bite force had a relatively short lower anterior height. The maximal bite force for molars and endurance amplitude were positively correlated to stature and finger force but not to facial characteristics. A longitudinal study to follow each individual child during growth would be of interest to evaluate the importance of muscular influence on facial growth.

Adult↗

PubMed1991

Characteristics of masticatory mandibular movements and velocity in growing individuals and young adults.

Studies of the development of mastication in the normal growing individual have received little attention in the literature. The aim of this study was to determine whether changes in oral motor function occurred during growth. Ninety healthy individuals with normal occlusion were divided into six groups of males and females, 9-10, 13-15, and 20-22 years of age. Oral motor function, with respect to mandibular displacement and velocity, was monitored with an opto-electronic method. The results revealed that the total duration of the masticatory cycle was not influenced by age or gender. However, the time distribution between the different phases was found to be influenced by the age factor, causing a longer opening time and a shorter closing time in the adults. In mastication, both mandibular displacement and the mandibular velocity in closing were less in females. A reduction of the masticatory opening velocity and an increase in closing velocity were observed with increasing age. Physiological maturation of the masticatory system due to central and peripheral changes and functional adjustments due to changes in dentition and skeletal growth may be the underlying reasons for our findings.

Adolescent↗