Utilising previous radiographs: the principle of dose optimisation.

OBJECTIVE: In dentistry, imaging is the most frequently used diagnostic tool. As a result, a steady increase in the use of imaging modalities are leading to an increase in healthcare cost and in patients' radiation exposure. RESULTS: 67-year-old patient attended for a surgical removal of lower left third molar. A sectioned panoramic radiograph showed an incidental finding of a well-defined, unilocular radiolucency apical to the lower left second and third molars. This was partially superimposed over the outline of the ID canal. A Stafne's bone cavity was considered as the most likely diagnosis. Further imaging was considered due to location not being fully below the ID canal as usually described in the literature. Reviewing previous imaging on PACS revealed the patient has had a CT angiogram of the head and neck 5 years prior. This showed a lingual bone defect of the surface of the mandible in the region of interest. The extension of the submandibular gland into the defect confirmed the likely nature of Stafne's bone cavity. CONCLUSION: This case highlights the essential role of reviewing (if in the same practice) or requesting (from a different practice) previous images. The international Commission for Radiological Protection regularly publishes data relating to the principles of dose reduction; Justification, Optimisation and Limitation. All examinations have to be justified to ensure the benefit to the patient outweigh the risk and radiation should be kept as low as reasonably achievable.

Computer-aided dynamic navigation: a novel method for guided endodontics.

OBJECTIVES: To investigate the novel use of computer-aided dynamic navigation for guided endodontics. METHOD AND MATERIALS: Dental casts were fabricated from sets of extracted human teeth. A cone beam computed tomography (CBCT) scan of each cast, with a molded thermoplastic stent and a radiographic marker attached, was obtained and imported into the planning software of a dynamic navigation implant surgery system. Simulating implant surgery but for guided endodontics, the drilling entry point, angle, pathway, and depth of virtual implants were planned for 29 selected teeth. The radiographic marker was replaced with a jaw tag and mounted in a phantom head. A drill tag was attached to the drill handpiece. Following calibration, guided by the stereoscopic motion-tracking camera via the tags and images on a computer monitor providing real-time dynamic plus visual intraoperative feedback, the handpiece was aligned accordingly and endodontic access cavity preparation carried out. Successful root canal location was confirmed using periapical radiographs and CBCT. RESULTS: Conservative access cavities were achieved and all the expected canals were successfully located in 26 teeth (n = 29). Due to tracking difficulties, only one canal was located in two maxillary second molars; in a maxillary first molar, only two canals were located and the access preparation for the third canal was misaligned and off-target. CONCLUSIONS: The results of this study demonstrate the potential of using computer-aided dynamic navigation technology in guided endodontics in clinical practice.

Effect of rituximab on a salivary gland ultrasound score in primary Sjögren's syndrome: results of the TRACTISS randomised double-blind multicentre substudy.

OBJECTIVES: To compare the effects of rituximab versus placebo on salivary gland ultrasound (SGUS) in primary Sjögren's syndrome (PSS) in a multicentre, multiobserver phase III trial substudy. METHODS: Subjects consenting to SGUS were randomised to rituximab or placebo given at weeks 0, 2, 24 and 26, and scanned at baseline and weeks 16 and 48. Sonographers completed a 0-11 total ultrasound score (TUS) comprising domains of echogenicity, homogeneity, glandular definition, glands involved and hypoechoic foci size. Baseline-adjusted TUS values were analysed over time, modelling change from baseline at each time point. For each TUS domain, we fitted a repeated-measures logistic regression model to model the odds of a response in the rituximab arm (≥1-point improvement) as a function of the baseline score, age category, disease duration and time point. RESULTS: 52 patients (n=26 rituximab and n=26 placebo) from nine centres completed baseline and one or more follow-up visits. Estimated between-group differences (rituximab-placebo) in baseline-adjusted TUS were -1.2 (95% CI -2.1 to -0.3; P=0.0099) and -1.2 (95% CI -2.0 to -0.5; P=0.0023) at weeks 16 and 48. Glandular definition improved in the rituximab arm with an OR of 6.8 (95% CI 1.1 to 43.0; P=0.043) at week 16 and 10.3 (95% CI 1.0 to 105.9; P=0.050) at week 48. CONCLUSIONS: We demonstrated statistically significant improvement in TUS after rituximab compared with placebo. This encourages further research into both B cell depletion therapies in PSS and SGUS as an imaging biomarker. TRIAL REGISTRATION NUMBER: 65360827, 2010-021430-64; Results.

Is there a role for ultrasound-guided balloon sialoplasty technique in salivary gland structures.

Ductal stricture is a common cause of obstructive salivary gland disease. Balloon dilatation of the parotid duct as a minimally invasive technique is currently carried out under fluoroscopic guidance or during sialendocopy. We present a case report of ultrasound-guided balloon dilatation. A 45-year-old female presented with a long history of obstructive symptoms affecting the right parotid gland. Ultrasound examination revealed a tortuous right main parotid duct with marked dilatation throughout its course and multiple sites of focal stricture formation. A sialogram was carried out to further characterize the ductal system, it showed significant dilatation of the main duct but due to overlapping of the elements of sialodochitis the visualization of the location and presence of strictures was very difficult. It was felt that ultrasound would be a better imaging modality to utilize in order to guide balloon dilatation of the strictures. Therefore, a balloon dilatation was carried out under ultrasound guidance. The main advantage of this technique is to preserve the physician and the patient from radiation exposure. In our knowledge this is the first case reported yet in the literature.

Anatomical relationship between mental foramen, mandibular teeth and risk of nerve injury with endodontic treatment.

OBJECTIVES: The objective of the present study was to evaluate the anatomical relationship between mental foramen (MF), including the incidence of the anterior loop of the inferior alveolar nerve (AL), and roots of mandibular teeth in relation to risk of nerve injury with endodontic treatment. MATERIALS AND METHODS: Cone-beam computed tomography (CBCT) images, which included teeth either side of the MF, were randomly selected. The anonymised CBCT images were reconstructed and examined in coronal, axial and sagittal planes, using three-dimensional viewing software, to determine the relationship and distance between MF and adjacent mandibular teeth. The actual distance between the root apex and MF was calculated mathematically using Pythagoras' theorem. If present, the incidence of an AL in the axial plane was also recorded. RESULTS: The root apex of the mandibular second premolar (70 %), followed by the first premolar (18 %) and then the first molar (12 %), was the closest to the MF. Ninety-six percent of root apices evaluated were >3 mm from the MF. An AL was present in 88 % of the cases. CONCLUSIONS: With regards to endodontic treatment, the risk of nerve injury in the vicinity of the MF would appear to be low. However, the high incidence of the AL highlights the need for clinicians to be aware and careful of this important anatomical feature. CLINICAL RELEVANCE: The risk of injury to the MN with endodontic treatment would appear to be low, but given the high incidence, it is important to be aware and be careful of the AL.

The effects of device position on the operator's radiation dose when using a handheld portable X-ray device.

INTRODUCTION: Handheld X-ray devices are now offered in dental practice. Handheld X-ray units challenge the concept of a restricted access to the "controlled area" as they are held by the operator. Although an integral lead shield is provided, the distance from the body is variable, dependent on how the device is held. The aim of this article was to investigate the level of operator dose when using a handheld X-ray device in various positions. MATERIAL AND METHODS: A NOMAD Pro™ Handheld X-ray system (Aribex Inc., Charlotte, NC) fitted with a remote control and mounted on a tripod was used in this study. A maxillofacial phantom ATOM(®) Max Dental and Diagnostic Phantom, model 711 HN (CIRS Inc., Norfolk, VA) was used to simulate the patient's head position. A mannequin was used to represent the operator. Pre-calibrated thermoluminescent dosemeters (TLDs) (Qados, Agar Scientific, Stansted, UK) were placed on the mannequin close to the eyes and at the level of thyroid, trunk, waist, hand (right finger + left palm) and feet, and three TLDs were used for background radiation. Three test scenarios were investigated; Position 1, close to operators' body and parallel to the ground; Position 2, away from the body with the arms fully extended (approximately 40 cm distance) and parallel to the ground; Position 3, perpendicular to the ground while the arms are partially extended. 30 exposures each of 1 s were performed in each test. RESULTS: Background radiation was measured at 0.0110 mGy. The highest exposure after subtracting background radiation was recorded on the palm of the left hand (0.0310 mGy) at Position 3. The estimated dose to the operator was calculated based on an average workload of 100 intraoral radiographs weekly for a dental practitioner working 46 weeks a year. CONCLUSIONS: There is a negligible increase in operator exposure levels using handheld X-ray devices which remain well below the recommended levels of the Ionizing Radiation Regulations 1999. They could however represent an increase from what should be a nil exposure when using a wall-mounted machine. The position of the device relative to the operator has a significant effect on the overall operator's radiation exposure. The use of personal dosemeters is highly recommended to ensure a continuity of low radiation dose exposure. Furthermore, guidance, training and protocols on usage must be in place, strictly adhered to and regular audits are necessary to ensure compliance.

Digital radiography in the dental practice: an update.

The implementation of digital imaging in dental practice should be considered. The vast number of advantages of digital imaging include time saving and image manipulation. Dose reduction is a big attraction but in practical terms this might not be fully taken advantage of, as a number of studies suggest. Challenges of images storage, back-up and exchange should be taken into account. Careful planning and integration with practice software should lead to a smooth transition. Remember, computer systems sometimes fail and contingency plans should be in place to avoid disruption to the workflow of the practice.

Cone beam CT in orthodontics: the current picture.

The introduction of cone beam computed tomography (CBCT) technology to dentistry and orthodontics revolutionized the diagnosis, treatment and monitoring of orthodontic patients. This review article discusses the use of CBCT in diagnosis and treatment planning in orthodontics. The steps required to install and operate a CBCT facility within the orthodontic practice as well as the challenges are highlighted. The available guidelines in relation to the clinical applications of CBCT in orthodontics are explored.