Current trends in the adoption and education of cone beam computed tomography and panoramic radiography machines across Australia

Abstract

Objectives:

This is a follow-up study to assess growth in the number of cone beam computed tomography (CBCT) and panoramic radiography (PR) machines in Australia. It is also the first study to evaluate the current status of both CBCT and PR education in Australia.

Methods:

CBCT and PR machine numbers were obtained from the radiation regulators across Australia. Australian dental schools were surveyed via email. The number of machines relative to population size and the number of dentists were calculated.

Results:

In 2020, there were 706 CBCT machines and 3,059 PR machines, representing a 204.3% increase in the number of CBCT machines and an 82.0% increase in the number of PR machines over six years. Majority of Australian dental schools owned PR and CBCT machines. Most taught PR acquisition and interpretation, however only one-third taught CBCT image acquisition and interpretation to predoctoral students.

Conclusions:

CBCT machine numbers increased by nearly three-fold while PR machines only increased by 1.6 times over a six-year period relative to population size and number of dentists. Only very few Australian dental schools provide CBCT education to predoctoral students, raising concern as to whether graduates are adequately trained upon program completion.

Introduction

Panoramic radiography (PR) and cone beam computed tomography (CBCT) are widely used modes of extraoral (EO) imaging in contemporary clinical dental practice. Where PR provides a broad but often distorted overview,¹ CBCT has the advantage of providing a three-dimensional (3D) representation of the craniofacial complex with submillimetre accuracy for a wide range of applications, a smaller physical footprint and reportedly lower radiation dose than conventional CT,² making it highly suitable for the private dental clinic. However, the average radiation dose delivered by CBCT remains greater than PR, and it falls to the dental practitioner to be responsible for the justification and optimisation of each exposure.

Significant disparity in use-licensing regulations and educational standards between countries worldwide and within Australia have been reported.^3–5 In Australia, practitioners are required to complete a recognised CBCT course in order to obtain a use-license.^6–15 Some countries have reported no mandatory requirements, with practitioners relying on limited training provided by the CBCT manufacturer or sales representative^4,16,17 to operate the irradiating apparatus. Differences in university curricula related to the teaching and training of CBCT has been noted across Europe,³ United Kingdom (UK), United States of America (USA) and Australia.⁴ To date, only one study has examined the teaching of CBCT in Australian universities.⁴ The necessity for standardisation of CBCT training, more comprehensive university-based training during predoctoral years, and more stringent registration procedures with continuing educational requirements has been raised.^3,16–20

The rapid growth of CBCT in the dental field has been repeatedly reported across the globe. In Australia, a study examining the number of Medicare rebated CBCT and PR services found that the rate of CBCT scans per 100,000 population had increased by 42.3% between 2011 and 2014.²¹ It is important to note that as Medicare is a part of the public health-care system, it does not capture data from other sectors and is likely to be a significant underestimation of the actual number of scans being taken.²² Interestingly, following change to the Medicare Benefits Schedule (MBS) in November 2014, which restricted CBCT rebates to only patients referred by medical practitioners and dental specialists, there was a reported 65.3% reduction in the number of rebated scans.²² It remains unclear whether this represents a true decrease in the number of CBCT scans taken nationally, or whether there is a shift towards image capture in the private dental sector on machines not funded by Medicare.

A pioneer study by Zhang, Critchley and Monsour in 2014 captured a snapshot of the number of CBCT and PR machines across Australia. Population size, number of dentists and use-licensing regulations were found to have a direct impact on the number of EO machines, whereas no significant correlation with gross state product (GSP) per capita was elicited.⁵ These were statistically significant only when data from New South Wales (NSW) and Western Australia (WA) were excluded as outliers. The reason for exclusion was due to ‘the data provided for NSW was not as comprehensive as the other States and Territories…and is unlikely to represent the real scenario’.⁵ On the other hand, the WA Radiation Safety Act restricted the ownership of CBCT machines in WA to dental practitioners who were registered with the Australian Health Practitioner Regulation Agency (AHPRA) in the speciality of dento-maxillofacial (DMF) radiology. With only two registered DMF radiologists in WA at the time,²³ it was not surprising that CBCT data from WA was highly skewed, highlighting the impact of licensing regulations on machine adoption.

The WA licensing regulations were revised in late 2017, with an amendment to the WA Radiation Safety Act that saw lifting of the aforementioned restriction. All Australian States and Territories now allow dentists to possess and use CBCT modalities on the proviso that registration requirements with the radiation regulator have been fully met. However, WA is uniquely resolute and requires CBCT images reported by an AHPRA registered medical radiologist or DMF radiologist.¹⁴

This current study is a follow-up census to quantify the changes in CBCT and PR machine numbers across Australia compared with the baseline values obtained in 2014 and to explore influence parameters (population size, number of dentists, and licensing regulations). Marked growth in CBCT ownership is hypothesised, particularly in WA following legislation changes. In lieu of “GSP per capita”, a new parameter of interest will be explored: the current status of CBCT and PR education in Australia and its impact on the national adoption of these EO imaging modalities.

Methods and materials

Data collection

De-identified information on all registered dental CBCT and PR machines including the quantity, manufacturer, make and model were requested via e-mail correspondence to the radiation regulators across Australia: Australian Capital Territory (ACT) Radiation Safety Health Protection Service; New South Wales (NSW) Hazardous Materials, Chemicals and Radiation Section; Northern Territory (NT) Radiation Protection Department; Queensland (QLD) Radiation Health Unit; South Australia (SA) Radiation Protection; Tasmania (TAS) Radiation Protection Unit; Victoria (VIC) Radiation Protection Branch; and Western Australia (WA) Radiological Council. Information was also requested from the Australian Radiation Protection and Nuclear Safety Agency (ARPANSA) for the machines owned by the Commonwealth government, and therefore, not recorded by the other radiation regulators.

The population figures for each Australian State and Territory were obtained from the Australian Bureau of Statistics (ABS) website for the quarter ending September 2019. Information on the number of dental practitioners was gathered from the Dental Board of Australia (DBA) Statistics website for the quarter ending March 2020.

In order to assess the extent of CBCT and PR education across Australian dental schools, a questionnaire was requested from the corresponding author of the study by Parashar et al³ and modified based on the requirements of this project: PR was added to the survey and the two questions regarding teaching of 3D CBCT images and orientation were combined for simplicity. The qualifications of the staff members involved in teaching radiography/radiology was also requested. The resulting eight-question survey and participant information sheet was emailed to the head of each dental school and relevant teaching staff.

Data analysis

Responses from all radiation regulators across Australia, including ARPANSA on behalf of the Commonwealth were obtained. The ACT regulator provided only approximate machine counts and the SA regulator only a total count of EO machines in that State. The raw data (excluding SA) were cross-checked for discrepancies; incorrectly recorded intraoral and orthopaedic radiography units were removed accordingly. The eventual data were categorised as CBCT or PR machines based on their manufacturer and model, rather than by their assignations in the raw data. The number of PR machines with the ability for upgrade to 3D imaging were also noted. Several machine model details were missing or inaccurately recorded, and it was necessary to assume that this data was correctly allocated by the radiation regulators.

Statistical analysis was carried out using IBM SPSS Statistics Subscription (IBM, New York, NY). It was necessary to remove the Commonwealth and dentists with no principal place of practice (PPP) from the ensuing analyses. Descriptive statistics for the number of machines per million population and per 1000 dentists were applied for both CBCT and PR machines. Data from the previous study by Zhang et al⁵ were collected and a comparison between the total and average number of machines was made. The widespread uptake of PR and CBCT machines was analysed with a statistical significance set at the 95% level.

A qualitative analysis of EO X-ray imaging education across the Australian dental schools was performed. The results relating to CBCT education at Australian universities in 2012 were extracted from the study by Parashar et al⁴ for comparison, and changes in CBCT education were noted. Additionally, the questionnaire data were analysed for trends in imaging education scrutinised against number of machines per State or Territory in Australia.

Results

Number of machines

The number of CBCT and PR machines by Australian State/Territory and the Commonwealth for the years 2014⁵ and 2020 are illustrated in Figure 1 and Figure 2. As of 2020, there was a total of 3,765 EO X-ray machines across the nation, comprising 706 CBCT machines and 3,059 PR machines. This represents a 204.3% increase in CBCT machines and an 82.0% increase in PR machines over six years since 2014. PR machines continue to outnumber CBCT machines, although this ratio has decreased from 7.25 times⁵ to 4.33 times, indicating an increased adoption of CBCT in Australia.

Figure 1.

Distribution of cone beam computed tomography (CBCT) machines across Australia

Figure 2.

Distribution of panoramic radiography (PR) machines, including machines upgradable to three-dimensional capability, across Australia

Queensland demonstrated the greatest ownership of CBCT machines (218), while NSW demonstrated the greatest number of PR machines (990). Excluding the machines owned by the Commonwealth, the NT continues to possess the smallest number of CBCT and PR machines (11 and 21, respectively). Although the findings indicated that NSW experienced the greatest percentage increase in both CBCT and PR numbers (962.5 and 304.1% respectively), it is noted that reliability of data from this State in 2014 was questionable. Allowing for this, WA demonstrated the greatest increase in CBCT machines (487.5%), while TAS reported the greatest increase in adoption of PR machines (144.8%); QLD recorded the greatest increase in absolute counts of CBCT and PR machines (an increase by 121 and 256 machines, respectively).

Of the 3,059 PR machines, 947 (31.0%) were able to be upgraded to 3D capability (Figure 2); NSW had the greatest absolute number of upgradable PR machines (361), representing 36.5% of the total number of PR machines in that State. However, by percentage distribution, VIC and QLD had a slightly larger percentage (37.1 and 37.0%, respectively) of upgradable PR machines.

Number of machines in relation to the population size and number of dentists

The population size for the quarter ending September 2019 and number of dentists (including specialists) for the quarter ending March 2020 per State or Territory are summarised in Table 1.^24,25 Corresponding data for the year 2014 were extracted from the previous study for reference.⁵ The number of CBCT and PR machines nationally (Tables 2 and 3) and for all Australian States and Territories (Table 4) were expressed as the average number of machines per million population and as the average number of machines per 1000 dentists.

Table 1.

The number of dentists, specialists and population size in Australia

State or Territory	Dentistsa (N)		Specialist (N)	Population (N)
	2014b	2020c	2020c	2014b	2020d
ACT	283	331	43	387,100	428,100
NSW	5,016	5,469	542	7,544,500	8,118,000
NT	104	111	6	246,300	245,600
QLD	3,013	3,664	355	4,740,900	5,115,500
SA	1,161	1,227	151	1,688,700	1,756,500
TAS	222	267	28	515,000	535,500
VIC	3,716	4,245	457	5,866,300	6,629,900
WA	1,635	1,849	201	2,589,100	2,630,600
No PPP	481	369	53	N/A	N/A
Total	15,631	17,532	1,836	23,577,900	25,459,700

ACT, Australian Capital Territory; NSW, New South Wales; NT, Northern Territory; PPP, principal place of practice; QLD, Queensland; SA, South Australia; TAS, Tasmania; VIC, Victoria; WA, Western Australia.

^aDentist includes both general and specialist.

^bAdapted from Zhang, Critchley and Monsour.⁵

^cFor the period January-March 2020.²⁴

^dFor the period July-September 2019.²⁵

Table 2.

Number of cone beam computed tomography (CBCT) and panoramic radiography (PR) machines per million population nationally

Modality	Year	Number of machines	Population size	Number of machines per million population	95% CI	Ratio of machine uptake
CBCT	2014	232	23,577,900	10	(5.52, 20.99)	2.80
	2020	707	25,459,700	28	(25.37, 43.29)
PR	2014	1,681	23,577,900	71	(51.10, 112.56)	1.69
	2020	3,059	25,459,700	120	(96.90, 158.90)

Table 3.

Number of cone beam computed tomography (CBCT) and panoramic radiography (PR) machines per 1000 dentists nationally

Modality	Year	Number of machines	Number of dentists	Number of machines per 1000 dentists	95% CI	Ratio of machine uptake
CBCT	2014	232	15,631	15	(10.80, 33.92)	2.67
	2020	707	17,532	40	(34.39, 73.71)
PR	2014	1,681	15,631	108	(92.83, 177.43)	1.61
	2020	3,059	17,532	174	(158.25, 240.44)

Table 4.

Number of cone beam computed tomography (CBCT) and panoramic radiography (PR) machines per State/Territory

Modality	State/Territory	Number of machines per million population		Ratio of machine uptake per million population	Number of machines per 1000 dentists		Ratio of machine uptake per 1000 dentists
		2014	2020		2014	2020
CBCT	ACT	31	49	1.58	42	63	1.50
	NSW	2	21	9.87	3	31	9.74
	NT	12	45	3.68	29	99	3.44
	QLD	20	43	2.08	32	59	1.85
	SA	12	37	3.12	17	53	3.08
	TAS	14	32	2.34	32	64	2.02
	VIC	12	24	2.03	19	37	2.00
	WA	3	18	5.78	5	25	5.20
PR	ACT	121	168	1.39	166	218	1.31
	NSW	32	122	3.76	49	181	3.71
	NT	57	86	1.50	135	189	1.41
	QLD	89	132	1.49	139	184	1.32
	SA	91	116	1.28	132	166	1.26
	TAS	56	133	2.35	131	266	2.04
	VIC	65	79	1.21	103	123	1.20
	WA	143	188	1.31	227	267	1.18

The average number of CBCT machines nationally in 2020 was 28 (95% CI: 25.35, 41.61) machines per million population and 40 (95% CI: 37.75, 70.35) machines per 1000 dentists. This represents a 2.80 and 2.67 times increase, respectively, when compared with the national averages from 2014. The average number of PR machines nationally in 2020 was 120 (95% CI: 102.21, 153.59) machines per million population and 174 (95% CI: 165.28, 233.41) machines per 1000 dentists. The growth rate for PR machines was less than CBCT, with only a 1.69 and 1.61 times increase, respectively, when compared with the averages from 2014.

By State/Territory, NSW demonstrated the greatest growth rate in CBCT and PR machines relative to all parameters. However, this finding should be interpreted with caution as previous 2014 data contained potential inaccuracies. Allowing for this, WA demonstrated the next greatest growth in CBCT machines per million population and per 1000 dentists (5.78 and 5.20 times, respectively); NT and SA also saw a growth rate above the national average in terms of both population size and the number of dentists. Regarding PR machines when NSW was excluded, TAS demonstrated the greatest growth rate per million population and per 1000 dentists (2.35 and 2.04 times respectively). The growth rates of PR machines for all other States/Territories were below the national average.

EO imaging education across the Australian dental schools

There was an excellent response from the dental schools, with eight out of the nine schools completing the questionnaire (88.9% response rate). Of those which provided a response, seven (87.5%) had PR machines while six (75.0%) owned CBCT machines. The remaining two schools expressed an interest in acquiring a CBCT machine in the near future.

Regarding the teaching of students in their predoctoral degree (BDSc, DMD, or DDS), seven out of eight schools (87.5%) taught predoctoral students to acquire PR images and all schools (100%) taught interpretation of PR images. The majority of schools did not provide extensive CBCT education: two out of eight schools (25.0%) taught acquisition, while three out of eight (37.5%) taught interpretation. Most included 3D CBCT images during teaching sessions (seven of eight = 87.5%). Only one dental school provided training to predoctoral students with implant software.

For students training to obtain a dental speciality under the Doctor of Clinical Dentistry (DCD) degree, two of the eight responding schools did not currently have dental specialist courses. Of the remaining six, three (50.0%) taught DCD students to acquire PR and CBCT images, five (83.3%) provided training for the interpretation of PR and CBCT images, and four (66.7%) provided training with implant software.

Only a small number of dental schools involved an AHPRA registered DMF radiologist or medical radiologist (three out of eight = 37.5%) for teaching, although two other universities employed an overseas trained DMF radiologist registered as a general dentist under AHPRA (25.0%). The majority of staff involved in radiography/radiology teaching across the Australian dental schools were general dentists (six out of eight schools = 75.0%), with two out of the eight schools (25.0%) employing only general dentists to teach students in oral radiology. One dental school (12.5%) utilised specialist dentists and an oral maxillofacial surgeon in the teaching of radiography/radiology.

Discussion

Current trend in extraoral machine adoption in Australia

This study confirms the increasing adoption of EO machines in dentistry across Australia. The adoption of CBCT is increasing at a significantly higher rate than PR, suggesting a trending shift towards CBCT ownership. The possibility that clinicians may opt to take more CBCT scans in place of PR given its advantages must be considered. Two Australian studies evaluating Medicare scan data found that there was a small but consistent drop in the number of PRs being requested, although it was not possible to unequivocally prove that CBCTs were being used as a substitute for PRs.^21,22 This would suggest an increase in radiation dose and financial cost to the population as a whole. It remains paramount to stress that CBCT should not be used as the initial imaging of choice and there should be enough justification and optimisation of each procedure to reduce the risk of radiation injury to patients. All personnel involved with CBCT must be adequately familiar with both the technology and imaged volume anatomy. The basic principles of CBCT and responsibilities of the practitioner have been extensively documented.^18,26

This rapid growth in CBCT is likely attributable to many factors, with changes in the population size and number of dentists reported to have a direct impact on machine numbers.⁵ The removal of CBCT rebate access to general dentists from the MBS in 2014 may have prompted dentists to purchase CBCT machines for their own clinics as opposed to out-sourcing the patient for an equally non-rebatable scan. Additionally, this growth may reflect the larger number of general dentists who are placing dental implants and undertaking orthodontic treatment, both of which frequently utilise CBCT data for treatment planning.²¹ Given that implants have been reported as the leading indication for CBCT acquisition,^17,20,27,28 there may be some weight to this theory, which could be investigated in the future.

It is interesting that the State of Queensland which had the third largest population and dentist number in Australia in fact recorded the greatest ownership of CBCT machines; a finding also present in the 2014 study.⁵ A possible explanation is that QLD has the greatest number of dental schools in Australia, all of which own CBCT machines. Our study found that two of the three dental schools in QLD provided training for predoctoral students to acquire CBCT scans and included 3D CBCT images in their teaching. Accordingly, QLD students will graduate with more exposure and confidence in using the modality and are therefore more likely to adopt it in their clinical practice.

Growth rate of extraoral machines in Australia

Although NSW recorded the greatest growth rate in both CBCT (962.5%) and PR (304.1%) machines from 2014 to 2020, it is uncertain whether this is a true representation of the situation given the potential inaccuracies in the 2014 data.⁵ If the previous data were indeed a gross underestimation of the number of machines in that State, it would undoubtedly skew the results of this current study.

By excluding NSW, WA emerges as the State with the greatest increase (487.5%) in CBCT machines. This is consistent with our hypothesis that there would be marked growth following the lifting of restrictions that were present under the WA Radiation Safety Act prior to late 2017. The impact of use-licensing regulations on machine ownership is again affirmed; the popularity and perceived importance of owning a CBCT machine in contemporary clinical dentistry is also highlighted. It should be noted that the average number of CBCT machines for WA derived from this study is still below the national average per population and dentists, suggesting the growth in WA is in its early stages with further increases to be seen. This slower uptake may relate to the obstacles involved in the integration of a new technology into the practice workflow, such as high initial cost and the time required to educate staff in its use and operation. A Norwegian survey investigating dentist opinions and experiences in the use of CBCT found that while most respondents were satisfied with the CBCT technique, most believed that its use was time-consuming and costly to the clinic given the need to have additional qualified personnel.²⁷ Furthermore, the WA Radiological Council maintains that all images must be interpreted by a board certified medical radiologist or DMF radiologist,¹⁴ and this has been proposed as a barrier to CBCT use, as communication with the radiologist was perceived as an obstacle.²⁷

Four of the eight States demonstrated growth rates of CBCT below the national average in terms of population size and number of dentists, suggesting a lagging uptake or saturation within the community. Local State/Territory conditions will likely have a major influence on the demand for CBCT machines; however, with only two time points of data currently, it is difficult to confirm the veracity of these suppositions. Six out of the eight States reported a below average uptake of PR machines, and considering the reduction in PR scans rebated as previously discussed,^21,22 it is reasonable to conclude an oversaturation of PR machines nationally with a shifting interest towards CBCT machines.

Roughly a third of the PR machines in 2020 had the capability for 3D upgrade, representing an almost doubling in percentage of such machines from 2014. This remains consistent with the assumption that these machines have been purchased with a view towards future 3D upgrade⁵ and the increasing perception of CBCT as a fundamental tool in clinical dentistry.

Australia versus global extraoral machine numbers

There remains limited data in relation to the adoption of CBCT and PR machines globally rendering it difficult to compare Australia on the international level. Historical research dating back to 2012 showed a rising uptake of CBCT machines internationally,^16,17,27,29 which is again reflected in more recent Australian data, present research included.

There is little information in recent years regarding PR machines. Moreover, with more models capable of upgrade to 3D image capture, there will be a blurring between CBCT and PR machine numbers as upgraded machines may no longer be registered as PR machines despite still retaining the function. In future research, it may be more practicable to consider the number of PR scans rather than the number of machines.

The difficulties in obtaining scan data to estimate the dose of ionising radiation to the Australian population are recognised.²¹ It is, therefore, unsurprising that such data are also limited globally. Future studies in Australia could be directed along this path of enquiry.

Education on extraoral imaging modalities

The number of Australian dental schools with CBCT machines has increased significantly, compared to 2012 where only one school possessed a CBCT machine,⁴ reflecting the popularity of this imaging modality in dental practice. There is no prior study evaluating PR education in Australia.

Basic CBCT training during predoctoral years has been considered ideal,³ but concerningly, the teaching of Australian predoctoral students (in relation to 3D image orientation, CBCT acquisition and inclusion of 3D images) has not significantly changed since 2012.⁴ Compared to predoctoral students, DCD students received more instruction related to CBCT acquisition and interpretation, representing a slight improvement compared with the standards in 2012.⁴ The emphasis of CBCT teaching in dental specialty courses is also reflected overseas.^4,28,30,31 No advances in the teaching of implant software was noted in our study, despite implant dentistry being found to be the most common indication for CBCT scans.^17,20,27,28 These findings imply that the CBCT educational experience in Australia is not growing proportionally with the adoption of the machines. This may relate to the steep learning curve required by educators to obtain and integrate CBCT knowledge into both the theoretical and practical components of teaching.³² Additionally, the time dedicated to radiology teaching may be limited. In a 2007 report, the International Association of Dento-maxillofacial Radiology (IADMFR) Education Standards Committee recommended no less than 80 hours for the teaching of DMF radiology to undergraduate students, although it recognised that the quality of teaching was more important than the quantity.³³ It is unclear how much time is dedicated to the teaching of oral radiology in the current predoctoral curriculum in Australia. Finally, much variability and uncertainty relating to the content and extent of CBCT teaching for dental students has been reported,^3,19 likely resulting in the slow incorporation of CBCT into the curriculum.

The standards for basic training in the use of CBCT by dental practitioners have been recommended;³ however, the extent to which these have been adopted remains uncertain. Recent survey studies investigating dental student and practitioner views on CBCT training at Universities suggested that most felt the instructions provided were insufficient.^20,32,34 A USA survey centred in Georgia found that only 13 out of the 129 respondents received CBCT training during their dental education,²⁰ identifying voids in CBCT education in the areas of radiation safety including using the appropriate exposure parameters, basic principles of CBCT including limitations of this modality, CBCT anatomy and pathology, and CBCT interpretation.^20,31 A basic, standardised CBCT course during the predoctoral years remains ideal.^3,20

There is merit in involving radiologists adequately trained in dentistry in the teaching of dental students and it has been proposed that oral radiology courses should be designed and delivered by DMF radiologists.¹⁹ This leads to increased awareness of the DMF radiology specialty which was found to be reduced in Australia,³⁵ and familiarity with the profession will aid dental students/practitioners in communication which was considered a barrier.²⁷ Consideration of the potential differences in knowledge depending on the country, date and type of qualification of staff when developing and implementing DMF radiology in the dental curriculum is necessary.³ The IADMFR report recommended that, where possible, at least one instructor in oral radiology should be a Board/College certified DMF radiologist.³³ Furthermore, with a 24.6–93.4%³⁶ likelihood of an incidental finding in a CBCT scan, and one in three of these findings requiring follow-up or referral,³⁷ there is significant benefit to both the patient and practitioner in working with an appropriately trained radiologist for the interpretation of CBCT scans,^19,31,35 particularly large volume CBCT scans. As the referring dentist is responsible for the entire scan volume and is held to the same standard as a specialist,^26,38 the perils of self-reporting and the potential resulting medico-legal consequences^19,35,36 are evident.

Given the limitations in predoctoral CBCT education, practitioners have been reported to supplement the deficiencies in their CBCT education with continuing education courses and professional reading material.³⁴ Interestingly, a Swedish survey found that dental practitioners who had attended a postgraduate course on oral radiology had 1.7 times higher odds of access to a PR unit and 1.9 times higher odds of having CBCT equipment.¹⁶ Currently in Australia, the only requirement related to CBCT use is the completion of an approved CBCT use-licence course, after which there are no specific requirements for continuing education in DMF radiology. The nature of this short compulsory course is unlikely to provide adequate practical experience necessary for continuing safe radiation practice. A Turkish study found that although CBCT teaching had been incorporated into the theoretical sessions, CBCT awareness of dental students remained low as there were no such machines in the dental schools.³² The importance of reinforcing theoretical training with practical experience has been documented.⁴

Limitations

It was not possible to eliminate potential inaccuracies from human or non-sampling error in the data collected from the radiation regulators, nor to verify the accuracy, quality and currency of the information obtained from the publicly accessible websites. The nature of the data collected did not allow for rigorous statistical testing and extrapolation of the CBCT and PR numbers beyond the scope of this study to predict future machine numbers. The factors influencing adoption of EO machines are unlikely to be limited to those explored in this study. The impact of the qualifications of the practitioner (general dentist versus specialist dentist), clinical indication, geographical location of the EO machine and the popularity of implant dentistry could be investigated in future studies, along with scope of teaching of CBCT education in Australia.

Conclusions

This follow-up study confirms the continued growth of EO imaging in Australia; particularly the extensive adoption of CBCT nationwide which has seen CBCT machine numbers increase by nearly three times while PR machines have only increased by 1.6 times over the six-year period in relation to population size and number of dentists. In particular, WA has seen a dramatic growth in CBCT machine numbers following lifting of the strict licensing regulations previously imposed.

To date, a low number of Australia’s dental schools provide CBCT education to predoctoral students raising concern as to whether graduates possess adequate knowledge for the safe use of this irradiating apparatus in clinical practice. With the greater adoption of CBCT machines, it is clear a basic, standardised CBCT course should be implemented during predoctoral training. This is the first study in Australia evaluating the dental curriculum relating to both PR and CBCT, as well as the qualifications of the staff involved in the teaching of radiology.