Automatic Synthesis of Panoramic Radiographs from Dental Cone Beam Computed Tomography Data

In this paper, we propose an automatic method of synthesizing panoramic radiographs from dental cone beam computed tomography (CBCT) data for directly observing the whole dentition without the superimposition of other structures. This method consists of three major steps. First, the dental arch curve is generated from the maximum intensity projection (MIP) of 3D CBCT data. Then, based on this curve, the long axial curves of the upper and lower teeth are extracted to create a 3D panoramic curved surface describing the whole dentition. Finally, the panoramic radiograph is synthesized by developing this 3D surface. Both open-bite shaped and closed-bite shaped dental CBCT datasets were applied in this study, and the resulting images were analyzed to evaluate the effectiveness of this method. With the proposed method, a single-slice panoramic radiograph can clearly and completely show the whole dentition without the blur and superimposition of other dental structures. Moreover, thickened panoramic radiographs can also be synthesized with increased slice thickness to show more features, such as the mandibular nerve canal. One feature of the proposed method is that it is automatically performed without human intervention. Another feature of the proposed method is that it requires thinner panoramic radiographs to show the whole dentition than those produced by other existing methods, which contributes to the clarity of the anatomical structures, including the enamel, dentine and pulp. In addition, this method can rapidly process common dental CBCT data. The speed and image quality of this method make it an attractive option for observing the whole dentition in a clinical setting.

Early detection of osteoporosis from incisure depth of human mandible in an orthopantomogram

OBJECTIVES

To see the correlation between changes in incisure depth of mandible on an orthopantomogram with bone mineral density and whether or not it can be employed for screening and early detection of osteoporosis.

METHOD

The analytical cross-sectional study was conducted at the Institute of Basic Medical Sciences, Dow University of Health Sciences, Karachi, from December 2011 to July 2012. It comprised 174 female subjects between 25 and 85 years of age who were divided into premenopausal (Group I) and postmenopausal (Group II) groups. Group I and Group II were further subdivided into normal (pre A, post A), osteopenic (pre B, post B) and osteoporotic (pre C, post C) groups on the basis of Dual EnergyX-ray Absorptiometry scan. Changes in mandibular incisure depth seen on orthopantomogram in subgroups of Group I were compared with each other and with subgroups of Group II. SPSS 16 was used for statistical analysis. One-way Analysis Of Variance was applied to evaluate intra-group significance. For inter-group significance, independent samples t-test was applied.

RESULTS

The depth of mandibular incisure was found to be significantly increased in osteoporotic patients (p < 0.05).

CONCLUSION

The simple screening tool can be employed for early detection of osteoporosis in a cost-effective manner.

Image and surgery-related costs comparing cone beam CT and panoramic imaging before removal of impacted mandibular third molars

OBJECTIVES

The aim of this prospective clinical study was to derive the absolute and relative costs of cone beam CT (CBCT) and panoramic imaging before removal of an impacted mandibular third molar. Furthermore, the study aimed to analyse the influence of different cost-setting scenarios on the outcome of the absolute and relative costs and the incremental costs related to surgery.

METHODS

A randomized clinical trial compared complications following surgical removal of a mandibular third molar, where the pre-operative diagnostic method had been panoramic imaging or CBCT. The resources implied in the two methods were measured with health economic tools. The primary outcome was total costs defined as the sum of absolute imaging costs and incremental surgery-related costs. The basic variables were capital costs, operational costs, radiological costs, radiographic costs, overheads and patient resource utilization. Differences in resources used for surgical and post-surgical management were calculated for each patient.

RESULTS

Converted to monetary units, the total costs for panoramic imaging equalized €49.29 and for CBCT examination €184.44. Modifying effects on this outcome such as differences in surgery time, treatment time for complications, pre- and post-surgical medication, sickness absence, specialist treatment and hospitalization were not statistically significant between the two diagnostic method groups.

CONCLUSIONS

Costs for a CBCT examination were approximately four times the costs for panoramic imaging when used prior to removal of a mandibular third molar. The use of CBCT did not change the resources used for surgery, post-surgical treatment and patient complication management.

What costs are associated with the management of third molars?

PURPOSE

The purpose of this study was to estimate the treatment costs directly related to operative and nonoperative management of asymptomatic, disease-free, third molar (M3) teeth.

MATERIALS AND METHODS

The data reviewed were limited to claims submitted by oral and maxillofacial surgeons. The data collected included charges for consultations, radiographs, surgical removal of bony impacted teeth, and general anesthesia, using the 2009 data extracts from Delta Dental of Virginia. The median charges were used as a proxy for the actual costs attributable to the removal or retention of M3 teeth. Three clinical scenarios were executed using the available claims data to calculate the treatment costs associated with nonoperative and operative M3 management. An assumption made in the computation of expenses was that for subjects who elected to retain their M3s, the recommended management strategy was active surveillance. Active surveillance is a prescribed treatment to monitor the retained M3s characterized by performing a clinical examination and panoramic imaging every 2 years. The author assumed a 3% increase in charges per annum.

RESULTS

The 3 scenarios were as follows: scenario 1 (nonoperative management), retention of asymptomatic, disease-free M3s and monitoring for 20 years from age 18 to 38 years; scenario 2 (operative management), removal of 2 asymptomatic, disease-free, bony impacted M3s for 18-year-old patients using general anesthesia (30 minutes) in an office-based ambulatory setting; and scenario 3 (failure of non-operative management), removal of 1 previously asymptomatic, disease-free, bony impacted M3 after 10 years of follow-up in a now 28-year-old patient using general anesthesia (30 minutes) in an office-based ambulatory setting. The estimated charges for managing M3s were $2,342, $1,184, and $1,997 for scenarios 1, 2, and 3, respectively.

CONCLUSIONS

A simplified financial analysis derived from the dental claims data suggests that during the course of the patient's lifetime, the charges associated with non-operative management of asymptomatic, disease-free M3s will exceed the charges of operative management. The difference in costs might be important to patients when choosing between operative and non-operative management of their M3s.

Correlating carotid artery stenosis detected by panoramic radiography with clinically relevant carotid artery stenosis determined by duplex ultrasound

OBJECTIVE

We sought to assess the utility of panoramic radiography as an adjunct screening tool for detecting significant asymptomatic carotid artery stenosis. The specific aim was to correlate calcifications seen in the region of the carotid bifurcation with clinically relevant carotid artery stenosis as determined by duplex ultrasound (DUS).

STUDY DESIGN

Routine dental panoramic films of patients 55 and older (n = 778) at the University of Rochester Eastman Dental Center were retrospectively reviewed for calcifications around the carotid bifurcation. Patients with such calcifications were referred for DUS, and raw data were interpreted by a vascular surgeon blinded to the radiographic findings. Groups were compared by using the chi(2) test.

RESULTS

Twenty-seven patients (3.5%) had suggestive radiographic calcifications on one or both sides, 20 of whom consented to DUS. Clinically significant carotid stenoses (>50% lumenal narrowing) were present in 50% of the sides with calcification compared with 21% of the sides without (P =.08, chi(2)). Three patients (15% of those screened with DUS) had stenoses greater than 80% and underwent 4 carotid endarterectomies as a direct result of screening.

CONCLUSIONS

Data suggest that clinically significant stenosis may exist if calcifications are observed on panoramic radiographs. Incidental examination of this area carries a minimal cost and appears beneficial as a screening tool for carotid disease, although definitive testing must follow.

Extraoral and panoramic systems

Digital solutions for extraoral and panoramic radiology have been available for more than 15 years. The costs, however, have been too high for adoption in private dental practice. The past 2 years have seen tremendous growth in the number of relatively cost-effective digital options available to the dentist and dental specialist. Furthermore, computer speed and data storage capacities have progressed. This article presents an overview of systems available at present, and their enabling technologies and enhancement capabilities.

[Value of dental CT for the implant specialty in mouth, jaw and facial surgery]

The importance of dental CT in comparison to conventional OPT in implantation diagnostics is demonstrated in specific indication groups (atrophy of upper and lower jaw, patient after tumor and reconstructive surgery). The application of radiological techniques is illustrated in relation to diagnostic information quality, radiation exposure and cost effectiveness regarding clinical routine use.

Panoramic and restrictive intraoral radiography in comprehensive oral radiographic diagnosis

It has been suggested that information from the panoramic radiograph makes it possible to appropriately select supplementary intraoral radiographs to achieve a comprehensive examination of teeth and surrounding bone with less patient dose but no significant information loss. Number of intraoral radiographs selected, information loss and monetary costs with such a procedure was evaluated in 40 patients. Results show that, on average, 5.1 intraoral radiographs were selected to supplement the panoramic radiograph. Of these, 3.1 contained information different from that in the panoramic radiograph but 2.0 did not. An additional 3.4 ought to have been taken to reach the result of the 'gold standard' achieved from a simultaneous evaluation by two expert observers of panoramic radiographs and full mouth surveys with intraoral radiographs. Sensitivity for the combined use of panoramic and supplementary intraoral radiographs was high (80-96%, depending on type of teeth) as regards periapical lesions and marginal bone loss but low for caries (42-96%). Specificity was high for periapical lesions and caries (95-97%) but low for marginal bone loss (50-92%). In Sweden, patient costs become almost the same for a combination of panoramic radiography and 8.5 intraoral radiographs as for a full mouth survey comprising 20 intraoral radiographs. The radiation dose reduction is 40-50% considering that the dose from a panoramic radiograph approximately corresponds to 2-4 intraoral radiographs.(ABSTRACT TRUNCATED AT 250 WORDS)

Rotational panoramic zonography

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