Does a narrow tubular collimator produce better dental radiographs?

Knowledge of oral radiology among Swedish dentists

OBJECTIVES

To develop a method of measuring Swedish dentists' knowledge of oral radiology and to relate the knowledge measure to a number of characteristics including risk attitude and use of low dose techniques.

METHODS

A questionnaire was mailed to 2000 randomly selected dentists listed in the register of the Swedish Dental Society, with a response rate of 69.2%. An index for measuring knowledge was constructed, based on the answers to the questions. The measure was cross-tabulated with a number of demographic variables.

RESULTS

Dentists with 5-25 years in practice had a higher level of knowledge than those with either fewer or more years in practice. Dentists working in the Public Dental Health Service had a higher level of knowledge compared with those in private practice. Specialists had a significantly higher level of knowledge compared with dentists who were not. Forty-two per cent of the dentists had not attended any course in oral radiology since graduation. Seventy-nine per cent of the dentists using a 'low' dose technique had a 'high' level of knowledge. The difference between dentists using a 'low-dose' and a 'high-dose' technique was statistically significant (P = 0.000). Dentists' attitude to risk is related to their knowledge. Seventy-one per cent of the dentists in counties with a specialist in oral radiology had a 'high level of knowledge' compared with 57% in those without.

CONCLUSIONS

It is possible to study the relationship between knowledge and demographic variables by a survey. Work experience and extended education affect dentists' knowledge. There is an association between knowledge, use of low-dose techniques and risk attitude.

The effect of beam collimation in lateral radiographic cephalometry

A study was carried out to compare the image contrast of lateral cephalometric radiographs taken with and without the modified beam collimation and to evaluate the effect of this on the reliability of cephalometric measurements. The findings indicated that the cephalographs taken with modified beam collimation consistently showed a higher image contrast than the cephalographs taken with standard beam collimation. Despite this, however, there was no significant difference in the reliability of cephalometric measurements between the two groups of films.

Thyroid dose distribution in dental radiography

The anatomic position and proven radiosensitivity of the thyroid gland make it an organ of concern in dental radiography. A calibrated thermoluminescent dosimetry system was used to investigate the absorbed dose (microGy) to the thyroid gland resultant from a minimum irradiated volume, intraoral full-mouth radiography technique with the use of rectangular collimation with a lead-backed image receptor, and conventional panoramic radiography performed with front and rear lead aprons. Use of the minimum irradiated volume technique resulted in a significantly decreased absorbed dose over the entire thyroid region ranging from 100% to 350% (p less than 0.05). Because this intraoral technique results in radiographs with greater image quality and also exposes the thyroid gland to less radiation than the panoramic, this technique may be an alternative to the panoramic procedure.