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Biomedical subjects

A S Johal

Publications and source records attributed to A S Johal.

6 recordsLinked to original sources
PubMed1997

Dental crowding: a comparison of three methods of assessment.

This study was designed to explore a new method for the assessment of dental crowding from study models, which would be both valid and reproducible. This was then tested against two previously reported strategies. A single examiner compared the following methods: visual examination, brass wire/callipers, and a reflex microscope with its customized computer program. Sixty study models (30 maxillary and 30 mandibular) were measured using each technique on two separate occasions. The results showed the reflex microscope method to be the most reproducible, followed by the visual examination and brass wire methods. When testing for validity, as there is no absolutely accurate standard of arch measurement, the individual methods must be compared with one another. From the results, it was seen that the mean values for dental crowding using the reflex microscope, in both the upper and lower arches, were very close to a value which equalled the average obtained from the two means of the visual examination and brass wire methods. The results also indicated that the visual examination and brass wire methods showed a positive bias towards over- and underestimating the degree of crowding, respectively.

Alloys↗
PubMed1997

Case report: infra-occluded deciduous molars: a review and alternative treatment approach.

A review of the literature regarding the prevalence, aetiology, clinical features and management of infra-occluded deciduous molars is presented. There is no general agreement as to the treatment of infra-occluded deciduous molars but extraction therapy is strongly recommended in the literature. The complications of nontreatment are discussed and an alternative treatment approach is presented.

Child↗
PubMed1996

The assessment of crowding without the need to record arch perimeter. Part II: Crowded and irregular arches.

A mathematically determined technique which seemed to be valid for the calculation of crowding and spacing in arches with acceptable alignment, was tested on a series of arches with varying degrees of crowding and irregularity. Upper and lower study casts of 30 individuals with sufficient malalignment and crowding to warrant orthodontic treatment with fixed appliances were examined. Models were measured by three operators, using a reflex microscope interfaced to an IBM compatible PC and a customized calculation program. The degree of crowding was compared with a "clinical' assessment of each arch, in which the irregularity was measured directly using a steel ruler. Both the computer calculated and clinical values varied between observers, but the agreement between observers was better using the reflex microscope. Correlation coefficients ranged from 0.92 to 0.96 for the reflex microscope, and between 0.86 and 0.91 for the clinical assessment. Inter-observer agreement for the three operators was high: 0.93 for the reflex microscope and 0.87 where a ruler was used. This suggests that the computer program used to calculate the crowding was valid for the crowded arches under consideration.

Algorithms↗