Biomedical subjects

A T Karlsen

Publications and source records attributed to A T Karlsen.

11 recordsLinked to original sources

PubMed1999

Morphology and growth in convex profile facial patterns: a longitudinal study.

Two groups of females, one with normal anteroposterior jaw-base relationships and the other with distal jaw-base relationships, were selected at age 6 and compared longitudinally up to age 18. The purposes of this study were, first, to reveal morphological factors that caused or contributed to a distal jaw-base relationship, and second, to compare growth in the two groups. A distal jaw-base relationship is not a morphological entity caused by some specific aberration in the cranial base or jaws. Rather, it is the result of a combination of predisposing deviations with varying degrees of gravity. A short mandibular corpus and a large MP-SN angle were the only deviations with significant group differences. Distal jaw-base relationships generally worsened with age as compared with normal anteroposterior jaw-base relationships. Inadequate increase in mandibular corpus length in the 6- to 12-year period contributed to the worsening, as did the mandible growing more vertically than normal after age 12.

Adolescent↗

PubMed1998

Longitudinal changes in Class I subjects with moderate mandibular skeletal protrusion.

Two groups of Class I females were followed from 6 to 18 years of age. At the initial evaluation, subjects in one group had normal sagittal jaw-base relationships, while those in the other group had moderate mesial relationships between the jaw bases. The purpose of this study was to compare craniofacial morphology and growth in these two groups. Subjects with mesial jaw-base relationships had mandibular skeletal protrusion due to a more forward positioning of the mandible relative to anterior cranial base. Other morphological group differences involved jaw-base relationships (but not jaw size). All the observed group differences were present at age 6; no new differences were observed later. Some differences stayed significant up to age 18, while others became less distinct with time. Incremental growth in the groups was comparable. Similar growth of the jaws apparently helped to maintain initial group differences in jaw-base relationships.

Cephalometry↗

PubMed1997

Association between facial height development and mandibular growth rotation in low and high MP-SN angle faces: a longitudinal study.

Two groups of children with low (n = 29) and high (n = 29) MP-SN angles were followed longitudinally from 6 to 15 years of age. The purpose was to thoroughly examine associations between vertical craniofacial growth and mandibular growth rotation. Correlations between dimensional and rotational variables occurred in different variable pairs in the two groups and changed with age. Increase in posterior lower facial height distinguished itself by being consistently positively correlated with forward matrix rotation irrespective of mandibular plane angle or age. The same applied to increase in ramus height. Increase in lower anterior facial height was, surprisingly, weakly correlated with mandibular rotation, but strongly and positively correlated with increase in corpus length. Overdevelopment of lower anterior facial height in high angle cases occurred because the steep mandibular plane directed corpus growth more downward than normal, not because the mandible rotated backward.

Adolescent↗

PubMed1995

Craniofacial growth differences between low and high MP-SN angle males: a longitudinal study.

Craniofacial growth was followed longitudinally in two groups of boys with low and high MP-SN angles. The purpose was, first, to reveal group differences in dimensional change, and second, to find whether such differences were associated with a group difference in mandibular growth rotation. Group differences in dimensional change were explained by a difference in matrix rotation of the mandibular corpus, especially in the 6- to 12-year period. In the 12- to 15-year period, matrix rotation was similar in the two groups and so were dimensional changes. Morphologically, dimensional group differences in the 6- to 12-year period were theoretically compatible with the fact that mandibular rotation was clearly more forward in the low angle than in the high angle group. Statistically, dimensional variables with significant group difference were correlated strongly with matrix rotation and, in most cases, non-significantly with intramatrix rotation.

Adolescent↗

PubMed1994

Craniofacial characteristics in children with Angle Class II div. 2 malocclusion combined with extreme deep bite.

Craniofacial characteristics in two groups of children were compared. In one group (n = 22) the children had Angle Class II division 2 malocclusion combined with extreme deep bite. The other group (n = 25) was composed of children with ideal occlusion. The mean ages of the children were 12.8 and 12.9 years respectively. In the Class II-2 group the distance between gonion and B-point was underdeveloped, causing B-point to have a retruded position in relation to both A-point and cranial base. The Class II-2 children also had a retroclination of the symphysis, which gave the B-point a retruded position in relation to pogonion. As for vertical dimensions, Class II-2 children had a smaller anterior lower facial height than normal. Furthermore, Class II-2 had a discrepancy between the maxillary incisal and molar heights, i.e. a slightly larger incisal height and a slightly smaller molar height. Finally, children with Class II-2 had a high lip line and a very large interincisal angle. Three variables--the sagittal distance between points A and B, the inclination of the symphysis, and the relationship between the maxillary incisal and molar heights--in combination, differentiated nearly 100% correctly between Class II-2 and normal occlusion.

Case-Control Studies↗

PubMed1994

Craniofacial morphology in children with Angle Class II-1 malocclusion with and without deepbite.

The craniofacial morphology of children with Class II-1 malocclusion with and without deepbite was studied and compared with that of a control group of children with normal occlusion. Common for the Class II-1 children was a short mandibular corpus, which was probably the main reason these children had a distal basal jaw relationship. The Class II children with deepbite differed from the control group in ways. They had: 1) a distal relationship between points A and B; 2) a distal relationship between points A and pogonion; and 3) a discrepancy in length between the corpora of the two jaws. These deviations discriminated nearly 95% correct between the deepbite group and the controls. The most characteristic deviations in the Class II children without deepbite, in relation to the controls, were: 1) a distal relationship between points A and B; 2) a small angle between the nasal plane and the anterior cranial base; and 3) a long mental process. These deviations discriminated about 95% correct between the experimental group and the controls. Many of the craniofacial differences between the Class II groups could, theoretically, be explained by the MP-SN angle being, on average, 9 degrees larger in the children without deepbite. Most typical was that this group has 1) a larger lower anterior face height, 2) larger maxillary and mandibular incisal heights, and 3) a more obvious distal relationship between points A and pogonion. In combination, these differences discriminated correctly between the Class II groups in 90% and 97% of the cases.

Adolescent↗

PubMed1979