Biomedical subjects

M Harkness

Publications and source records attributed to M Harkness.

26 records · Page 2Linked to original sources

PubMed1996

Associations between changes in selected facial dimensions and the outcome of orthodontic treatment.

The purpose of this study was to determine, in children with Class II, Division I malocclusion who were treated with functional appliances, the strength of the associations between the changes over 18 months in selected facial dimensions and the success of orthodontic treatment as determined by the weighted Peer Assessment Rating (PAR). Forty-two children, between 10 and 13 years of age (mean age 11.6 years), were randomly assigned to either an untreated group (control) or a group treated with either a Fränkel function regulator or Harvold activator (treatment). The outcome of treatment was assessed on study models and the craniofacial changes were measured on lateral cephalometric radiographs. Correlation coefficients were then calculated between the differences in the cephalometric variables over 18 months and the differences in the PAR scores. In the treatment group, the effects of normal growth were held constant by partial correlation. The partial used was the change in both stature and weight. Significant positive partial correlations were found between the increases in total anterior face height, posterior face height, S-Pg, and treatment success. Significant negative partial correlations were found between downward movement of the maxilla and mandibular body and lower anterior face height and treatment success. It is postulated that these associations occurred mainly in response to the bite opening by the appliances. Treatment success was also significantly associated with maxillary restriction, an increase in the SNB angle and a reduction in the ANB angle. Changes in B point due to proclination of the mandibular incisors were considered to be responsible for the two latter significant associations. Although mandibular length increased significantly in the treatment group, as compared with the control group, it was not significantly associated with treatment success.

Activator Appliances↗

PubMed1995

A lateral cephalometric analysis of the adult nose.

PURPOSE: The purpose of this study was to establish a set of standard values for the form of the nose and its relationship to other craniofacial structures in young adult caucasians. SUBJECTS AND METHODS: The subjects were 50 (25 male, 25 female) caucasian dental students who gave no history of orthodontic treatment, facial surgery, or facial fractures. Lateral cephalometric radiographs were used to determine the form of the nose and its position relative to other craniofacial structures. RESULTS: The men had significantly longer and straighter noses than the women, and their noses also projected further from the face. The dorsum of the nose was straight in most subjects. The vertical distances from the tip of the nose to the most prominent part of the upper lip, to the incisal edge of the maxillary central incisor, and to soft tissue pogonion were significantly greater in the men. There were no gender differences in the horizontal distances between the same points and the tip of the nose. Subnasale was significantly more prominent in the men. CONCLUSIONS: In general, the findings of nasal form and position are in agreement with previous studies. Several gender differences in nasal form and position were found. The standards reported should prove to be a useful yardstick for clinicians engaged in procedures likely to alter the form of the adult human face.

Adolescent↗

PubMed1993

Mandibular changes during functional appliance treatment.

The purpose of this prospective trial was to determine the changes in position and size of the mandible in children treated with either the Fränkel function regulator or Harvold activator. Forty-two 10- to 13-year-old children with Class II, Division 1 malocclusions were matched in triads according to age and sex and randomly assigned to either control, Fränkel function regulator, or Harvold activator groups. There were no statistically significant differences between the groups at the beginning of the study. After 18 months, significant increases in gonial angle and articulare-pogonion length in the Harvold group were attributed to a change in the location of articulare because the condyles were positioned downward and forward at the end of treatment. The main effects of both appliances were to allow vertical development of the mandibular molars and increase the height of the face. The Harvold appliance also proclined the lower incisors and increased mandibular arch length. We could find no evidence to support the view that either appliance was capable of altering the size of the mandible.

Activator Appliances↗

PubMed1990

Hb Sun Prairie or alpha(2)130(H13)Ala----Pro beta 2, a new unstable variant occurring in low quantities.

A severe hemolytic anemia with microcytosis and hypochromia was present in a young adopted Indian patient. Reversed phase high performance liquid chromatographic methodology and heat stability tests detected an unstable alpha chain which was present in 3 to 5% of the total hemoglobin. A larger quantity of the alpha X chain was obtained by preparative reversed phase high performance liquid chromatography. Structural analyses identified an Ala----Pro replacement at position 130 of the alpha chain. The instability of the variant, named Hb Sun Prairie, is comparable to that of Hb Bibba [alpha 136 (H19)Leu----Pro]. Gene mapping failed to detect an alpha-thalassemia deletion (alpha alpha/alpha alpha), while dot-blot analysis of amplified DNA with synthetic probes localized a G----C mutation in codon 130 (resulting in the Ala----Pro mutation) of the alpha 2-globin genes of both chromosomes. These results suggest a homozygosity for the G----C mutation and the condition alpha 2(G----C)alpha 1/alpha 2(G----C)alpha 1 adequately explains the rather severe clinical status of this child, including the marked microcytosis and hypochromia. Unfortunately, family studies to exclude the presence of a large deletion involving all zeta- and alpha-globin genes were not possible.

Amino Acid Sequence↗

PubMed1973