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Biomedical subjects

W J Kerr

Publications and source records attributed to W J Kerr.

At least 55 records · Page 3Linked to original sources
PubMed1992

A comparison of laryngeal mask airway with tracheal tube for intra-ocular ophthalmic surgery.

The use of the laryngeal mask was compared with tracheal intubation in 30 patients who underwent intra-ocular ophthalmic surgery and who received intravenous anaesthesia with propofol. Changes in intra-ocular pressure, heart rate and mean arterial pressure after the insertion of the laryngeal mask airway or the tracheal tube were not significantly different. However, at the end of the procedure, a significantly higher percentage of patients with a tracheal tube coughed, reacted to head movement and suffered breath-holding. In addition, significantly more patients in this group complained of a sore throat (p less than 0.05). During intravenous propofol anaesthesia, the laryngeal mask airway does not offer any advantage over tracheal intubation in the control of intra-ocular pressure for intra-ocular ophthalmic surgery. However, there were fewer complications immediately following surgery in the laryngeal mask group.

Anesthesia, Intravenous↗
PubMed1992

Class III malocclusion: surgery or orthodontics?

The pre-treatment lateral cephalograms of two groups of 20 subjects with severe Class III malocclusions were compared. One group had been considered suitable for orthodontic correction by the diagnosing clinician and the other offered orthognathic surgery. The most significant differences between the groups were in angle ANB, M/M ratio (P less than 0.001), lower incisor inclination and Holdaway angle (P less than 0.01). Threshold values for angle ANB and lower incisor angulation below which surgery was almost always carried out were--4 and 83 degrees, respectively.

Adolescent↗
PubMed1991

The variability of some craniofacial dimensions.

The variability of eight linear and five angular dimensions measured on 124 lateral skull radiographs of 10-year-old boys was assessed by means of Bartlett's test for homogeneity of variances and Pitman's test for the comparison of correlated standard deviations. The linear dimensions which demonstrated the greatest variability within the four constituent Angle classes (N = 31) were mandibular body length, total cranial base length, total mandibular length and lower face height. The dimensions which demonstrated the least intra-group but greatest inter-group variability were maxillary length and Angle SNB. The Class II division 2 group exhibited the greatest variation in skeletal morphology; it is therefore postulated that its etiology is mainly dentoalveolar and soft tissue in origin.

Cephalometry↗
PubMed1991

The areas of various surfaces in the human mouth from nine years to adulthood.

Surface area measurements of five regions of the oral cavity were made from study casts of 57 subjects with an age range from 9.3 to 19 years. While the longitudinal pattern of growth exhibited by the total of the five areas, when subgroups were compared, was characterized by a steady increase to around puberty (13 years), followed by a plateau, different areas showed different patterns of growth. Increase in the surface area of the teeth was associated with the eruption of the second and third molars, whereas the area of the buccal lingual mucosa continued to increase into adult life. The palate, buccal vestibular mucosa, and dorsum of the tongue demonstrated a typically skeletal pattern of growth, i.e., increase until puberty with a rapid cessation thereafter. The results of this study indicate the need for longitudinal data to further knowledge concerning growth of the oral cavity.

Adolescent↗
PubMed1990

Panel perception of facial attractiveness.

The full-face and profile photographic transparencies of 60 subjects (30 male, 30 female) divided equally among Angles Class I, Class II Division 1, and Class III malocclusions, taken before and after orthodontic treatment, were randomly distributed in projector carousels and shown to four panels consisting of orthodontists, dental students, art students, and the parents of children undergoing orthodontic treatment. The faces were rated according to the method of Lundstrom et al. (1987). Full-face views generally were rated more attractive than profile views and Class II and Class III malocclusion subjects were rated lower than Class I malocclusion subjects. While the art student and parent panels were less critical in their appraisal of facial attractiveness, they were less sensitive to the changes brought about by orthodontic treatment than the orthodontist and dental student panels, although all could appreciate an improvement in the Class II Division 1 group.

Adolescent↗
PubMed1989

Mandibular form and position related to changed mode of breathing--a five-year longitudinal study.

A five-year follow-up study was performed on 26 children treated for nasal obstruction by adenoidectomy, who exhibited a changed mode of breathing postoperatively. They were compared with a control group matched according to age and sex. Lateral skull radiographs were used to examine mandibular morphology. The mandibular outline was registered using 36 digitized points. This method of portraying growth changes provides a valuable complement to isolated measurements. The technique revealed a more anterior direction of symphyseal growth in the adenoidectomy group following surgery as well as some reversal of the initial tendency to a posterior rotation of the mandible.

Adenoidectomy↗
PubMed1989

A comparison of skeletal and dental changes produced by function regulators (FR-2 and FR-3).

The lateral skull radiographs of subjects taken before and after treatment with the FR-2 (N = 99) and FR-3 (N = 30) of Fränkel were compared to contrast the effects of each appliance. The major skeletal effect of both appliances was on the mandible, the FR-2 group showing a significantly greater annual increase in total length and ramus height (P less than 0.001) and the FR-3 group a significant change in position downward and backward facilitated by an opening of the cranial base angle. The greater annual increase in lower facial height, compared with a control group, seen in both FR groups was accompanied by a reduction in overbite, which was greater in the FR-2 group. The favourable change in overjet seen in both FR groups was contributed to by alteration in upper and lower incisor inclination.

Activator Appliances↗
PubMed1988

Cranial base and jaw relationship.

The lateral skull radiographs of 124 boys aged approximately 10 years divided equally between the four angle classes were digitized in an effort to establish the relationship between cranial base size and shape and jaw relationship. Comparison of the means for occlusal groups showed a trend from class II to class III as cranial base dimensions and angle decreased. The condyle was also more distally positioned with respect to nasion, point A and the Pterygomaxillary vertical in the class II groups. Cranial base length correlated strongly with maxillary length but weakly with mandibular length. Nevertheless, the size of the maxilla did not influence its prognathism. The cranial base angle was strongly correlated (-0.7) with angle sella-nasion-point B. It is concluded that cranial base size and shape influence mandibular prognathism by determining the anteroposterior position of the condyle relative to the facial profile.

Cephalometry↗
PubMed1988

Mandibular position in class III malocclusion.

Lateral skull radiographs of 66 subjects with Class III malocclusion, characterized by lingual occlusion of the upper incisors and a degree of overbite, taken before and after treatment were compared with a Control Group of similar mean age and interval between films. Vertical, Horizontal and Oblique measurements were made to establish the part played by overclosure and anterior displacement of the mandible in the aetiology of Class III malocclusion. The results suggest that both may play a part but that the former is of more general significance than the latter.

Cephalometry↗
PubMed1987

Craniofacial characteristics of subjects with normal and postnormal occlusions--a longitudinal study.

Lateral skull radiographs of 85 growth study children taken at 5, 10, and 15 years of age, with normal/Class I occlusion (normal) and Class II, Division 1/Division 2 occlusion (postnormal) were digitized and analyzed by means of stepwise discriminant analysis. The cranial base angle proved to be the best discriminator between the two groups, the value at age 5 years being an accurate predictor of the occlusal type at 15 years in 73% of subjects. Although the majority of subjects grew predictably, their craniofacial characteristics being compatible with their ultimate occlusal type, 17% showed a growth trend from postnormal to normal and 9% a trend from normal to postnormal. By 15 years of age, only 8% of subjects possessed an occlusion at variance with their facial type. The cranial base angle is suggested as the fundamental determinant of jaw relation, but in some subjects this may be compensated by differential jaw growth manifested by a change in angle ANB.

Adolescent↗
PubMed1987

Changes in soft tissue profile during the treatment of Class III malocclusion.

The changes in soft tissue profile for 66 Angle's Class III malocclusion subjects treated either with the Function Regulator, or Upper Removable Appliances, or the Edgewise Appliance were assessed by comparing cephalometric radiographs taken before and after correction of the anterior occlusion. While the mean soft tissue profile in all groups improved in relation to a Control Group, the FR.III Group demonstrated the most profound change.

Activator Appliances↗
PubMed1987

Arch dimensional changes during and following fixed appliance therapy.

A retrospective investigation of the study casts of 23 subjects, treated by Fixed Appliances and the extraction of four premolars, using the Reflex Metrograph showed a general trend for a reduction in mean arch dimensions both during and following treatment. An exception was demonstrated in the intercanine width, which for both arches showed slight expansion during treatment, although this was lost post-treatment in the mandibular arch while it was maintained in some cases in the maxillary arch.

Cephalometry↗
PubMed1985

The nasopharynx, face height, and overbite.

In lateral cephalometric films of a group of male subjects, none of whom was a mouth breather, the statistical relationships between overbite and nasopharyngeal dimensions were weak. Moderate relationships were found between face height and nasopharyngeal dimensions. Strongest correlations, with a peak at 10 years, were between--Face height and nasopharyngeal height (+) Face height and nasopharyngeal area (+) Face height and roof angle (-) Dynamic correlations between overbite, face height and nasopharyngeal dimensions were weak. Class II malocclusion subjects on average showed--Smaller Nasopharyngeal and Adenoid Areas. Larger Airways in both real and proportional terms, compared with Class I and normal occlusion subjects.

Adolescent↗