Attitude of General and Specialist Dental practitioners towards Radiation Safety Principles

Introduction

Radiography is a necessary tool for treatment recognition, planning and efficacy. The information provided by the radiography is for the patients’ benefit, although the exposure is considered to be potentially harmful (1). More than 330 million dental imagings are performed annually, most of which are intraoral examinations (2). The radiation dose might be low for each examination, but patients are exposed to repeated examinations during dental follow-ups (3). The long-term health effects of low dose exposures is uncertain (4); however, studies show an association between radiation exposures and incidence of salivary gland and thyroid cancers, and intracranial meningioma (5-7).  Principles on the use of ionizing radiation exist in Iran, although little data is available on how they are applied in the dental field. It is important to adhere to the “as low as reasonably achievable principle” (ALARA) and maintain minimal exposure (8). It is possible to improve image quality along with reduced radiation dose if dentists follow the standard radiographic safety principles. The American Dental Association recommends the use of fast image receptors (F speed film or digital), beam limitation best achieved by rectangular collimation, personnel dosimeters and lead aprons, and thyroid collars when appropriate (9).

Nowadays intraoral radiography devices are being routinely used by general and specialist dentists. The influence of factors such as dental specialty and faculty membership on radiographic practice has rarely been studied in Iran. The objectives of this study were to determine the radiographic techniques and facilities used by dental practitioners and to assess whether dentists’ specialty and faculty membership impacted the choice of the intra-oral receptor, collimation method, image acquisition techniques, or methods of shielding. Determining the knowledge of our dentists and their implementation towards radiation safety measures, will insure the management of future academic programming, and monitoring strategies.

Materials and Methods

A total of 232 private dental offices with intraoral radiographic devices in Mashhad, Iran were randomly selected. The study protocol was approved by the institutional review committee. Radiation safety standards according to ADA recommendations during dental radiographs were considered (9). Demographic characteristics of dentists as well as radiographic equipment including image receptors, collimation, film holders, protection methods for patient and personnel, and bisecting or paralleling techniques were recorded in a checklist. The dental practitioners’ confidentiality was maintained. The respondents were classified into two groups including general dental practitioners (GDPs) (n=190) and dental specialists (n=42). Dental specialists were then grouped into faculty members and non-members. Frequency tables were provided according to the data and the statistical analysis was performed by Statistical Package for the Social Sciences (SPSS v.23). Chi-square test was used to determine the significance of differences between two independent groups at P=0.05 level.

Results

Demographic Data

Of the 232 dental practitioners, 190 (81.9%) dentists were in general dental practice (GDP) and the remaining 42 (18.1%) worked as specialists in different dental fields. 22 (52.4%) of the specialists were endodontists and the rest qualified in other fields. Males comprised 135 (71.1%) of GDPs and 26 (61.9%) of the specialists. The average age of all participants was 43.8 ± 8.5 years (range 26-70 years). The majority of GDPs (50.9%) had practiced dentistry for 10-20 years, 22.3% had below 10 years of practice and 26.9% had practiced for over 20 years. Whilst, most specialists (57.1%) had below 10 years of practice, 28.6% practiced for 10-20 years and 14.3% for over 20 years. Among the specialists, 19 (45.2%) had faculty membership.

Radiographic Equipment and Techniques

The E-speed film was used by 179 (77.1%) dentists while digital sensors were used by 47 (20.3%) and 6 (2.6%) dentists used both receptors. None of the dentists used F-speed films. Of the 47 dentists using digital sensors, 32 (68.1%) were GDPs. Regarding the use of image receptors, the study found a significant difference (P<0.05) between the two groups with 15 (35.7%) specialists using digital sensors compared with 32 (16.8%) GDPs. The results of the kVp settings show that the majority of both general and specialists’ dentists operate at 60-70 kVps. 37 specialists (88.1%) and 157 (82.7%) of GDPs reported using an X-ray device with a long-cone providing a 20 cm or greater focus-to-object distance. Overall, the majority of dentists (87%) used round collimation and only 7.3% of the dentists used rectangular collimation. The type and length of collimation utilized did not vary significantly between GDPs and specialists. Paralleling technique using film holders was employed by 28.6% of specialists and 10% of the general dentists (p<0.05). 32 (76.2%) specialists and 149 (78.4%) GDPs reported that they undertake the radiography themselves.

The frequency of image receptors, type and length of collimation, film holder usage, kVp settings and the radiographic technique (parallel and/or bisecting angle) in comparison between general and specialist dental practice are shown in Table I.

Table I The frequency of radiographic equipment and techniques in general and specialist dental practice

Patient and Personnel Protection

In general, 75 (32.3%) and 73 (31.5%) dentists used thyroid shields, and lead aprons respectively, in their practice for all patients and 14 (0.6%) and 32 (13.8%) used them only for pregnant women and children.

Half of the specialists utilized regular thyroid shielding; however, only 28.4% of the GDPs followed this practice (P<0.05). When evaluating the use of lead aprons, there was a significant difference between the specialists and GDPs. Of the former, 15 (35.7%) reported that lead aprons were used regularly, whilst 12 (28.6%) use them occasionally. 58 (30.5%) GDPs stated that lead aprons were used regularly, while 20 (10.5%) occasionally used them (Table II).

Table II The frequency of patient and personnel protection methods in general and specialist dental practice

Overall, 202 (87.1%) dentists used either the position and distance rule or a lead barrier for their own protection. 30 of the dentists did not use any personnel protection method. Specialist dentists showed a higher (88.1%) use of the lead wall/partition for their personnel protection. Statistically, a significant difference was found between GDPs and specialists regarding the use of any personnel protection method (p<0.05). Although not significantly different, 40.5% of the specialists changed the exposure time properly for different patients compared to 30% in the GDPs. (Table II)

Influence of Faculty Membership

19 (45.2%) specialists held faculty membership. To test whether radiographic practice differed with faculty membership, specialist dentists were grouped according to faculty membership and Chi-square tests were carried out. Non-faculty members used lead aprons more often (p<0.05) than faculty members. Use of a rectangular collimation, long cone, and thyroid shield, except variable exposure time were more common in non-faculty members, although not significantly different (Table III). The percentage of radiographic exposures conducted by a dental nurse was reported as ranging from 15.8% in faculty-members to 30.4% in non-members.

Table III The frequency of radiographic equipment and protection methods in specialist dental practice

*Significance is established between two columns for each variable (Pearson’s chi-square test)