The diagnostic efficacy of cone beam CT for impacted teeth and associated features: a systematic review.

This review evaluates the evidence for the diagnostic efficacy of cone beam computed tomography (CBCT) for impacted teeth and associated features. PubMed, Embase and the Cochrane Library were searched using specific indexing terms and reference lists were hand searched. Two reviewers selected relevant publications on the basis of pre-determined inclusion criteria. Original studies were assessed using a modification of the quality assessment of diagnostic accuracy studies (QUADAS) tool. The literature search yielded 96 titles, of which 7 were included in the review. There was only limited evidence for diagnostic efficacy expressed as sensitivity, specificity and predictive values. Only two studies compared CBCT and panoramic radiographs with a valid reference method and presented the results in terms of percentage of correct diagnoses. This review reveals a need for studies that meet methodological standards for diagnostic efficacy of CBCT in the diagnosis of impacted teeth.

Pre-surgical treatment planning of maxillary canine impactions using panoramic vs cone beam CT imaging.

OBJECTIVES: The aim of this prospective study was to compare the impact of using two-dimensional (2D) panoramic radiographs and three-dimensional (3D) cone beam CT for the surgical treatment planning of impacted maxillary canines. METHODS: This study consisted of 32 subjects (19 females, 13 males) with a mean age of 25 years, referred for surgical intervention of 39 maxillary impacted canines. Initial 2D panoramic radiography was available, and 3D cone beam CT imaging was obtained upon clinical indication. Both 2D and 3D pre-operative radiographic diagnostic sets were subsequently analysed by six observers. Perioperative evaluations were conducted by the treating surgeon. McNemar tests, hierarchical logistic regression and linear mixed models were used to explore the differences in evaluations between imaging modalities. RESULTS: Significantly higher confidence levels were observed for 3D image-based treatment plans than for 2D image-based plans (p < 0.001). The evaluations of canine crown position, contact relationship and lateral incisor root resorption were significantly different between the 2D and 3D images. By contrast, pre- and perioperative evaluations were not significantly different between the two image modalities. CONCLUSIONS: Surgical treatment planning of impacted maxillary canines was not significantly different between panoramic and cone beam CT images.

Variability of dental cone beam CT grey values for density estimations.

OBJECTIVE: The aim of this study was to investigate the use of dental cone beam CT (CBCT) grey values for density estimations by calculating the correlation with multislice CT (MSCT) values and the grey value error after recalibration. METHODS: A polymethyl methacrylate (PMMA) phantom was developed containing inserts of different density: air, PMMA, hydroxyapatite (HA) 50 mg cm(-3), HA 100, HA 200 and aluminium. The phantom was scanned on 13 CBCT devices and 1 MSCT device. Correlation between CBCT grey values and CT numbers was calculated, and the average error of the CBCT values was estimated in the medium-density range after recalibration. RESULTS: Pearson correlation coefficients ranged between 0.7014 and 0.9996 in the full-density range and between 0.5620 and 0.9991 in the medium-density range. The average error of CBCT voxel values in the medium-density range was between 35 and 1562. CONCLUSION: Even though most CBCT devices showed a good overall correlation with CT numbers, large errors can be seen when using the grey values in a quantitative way. Although it could be possible to obtain pseudo-Hounsfield units from certain CBCTs, alternative methods of assessing bone tissue should be further investigated. ADVANCES IN KNOWLEDGE: The suitability of dental CBCT for density estimations was assessed, involving a large number of devices and protocols. The possibility for grey value calibration was thoroughly investigated.

Comparison of cone beam CT device and field of view for the detection of simulated periapical bone lesions.

OBJECTIVE: We aimed to assess the diagnostic accuracy of different cone beam CTs (CBCTs) and the influence of field of view (FOV) in diagnosing simulated periapical lesions. METHODS: 6 formalin-fixed lateral mandibular specimens from pigs were used for creating 20 standardized periapical bone defects. 18 roots were selected for the control group. Three CBCT devices [Accuitomo 3D® (Morita, Kyoto, Japan), NewTom 3G (Quantitative Radiology, Verona, Italy) and Scanora® (Soredex, Tuusula, Finland)] and three FOVs (NewTom 3G® FOV 6, 9 and 12 inches) were used to scan the mandible. Five observers assessed the images, using a five-point probability scale for the presence of lesions. Specificity, sensitivity and areas under the receiver operating characteristic (ROC) curves were calculated. RESULTS: Sensitivity ranged from 72% to 80%. Specificity ranged from 60% to 77%. A difference in scoring between Scanora and the other two devices existed only in the control group. ROC analysis for different FOVs showed a decreased sensitivity with an increasing FOV, but this difference was not significant. CONCLUSION: the control group, there was a difference between the CBCT devices regarding their specificity. FOV size did not show any difference in diagnostic performance. In cases in which conventional radiographic methods in combination with clinical evaluation are not sufficient, CBCT may be the method of choice to assess periapical pathology. CBCT examinations should be complementary to a clinical examination and FOV adaptation can be utilized to keep the dose to the patient as low as possible.

Variation in costs of cone beam CT examinations among healthcare systems.

OBJECTIVES: To analyse the costs of cone beam CT (CBCT) in different healthcare systems for patients with different clinical conditions. METHODS: Costs were calculated for CBCT performed in Cluj (Romania), Leuven (Belgium), Malmö (Sweden) and Vilnius (Lithuania) on patients with (i) a maxillary canine with eruption disturbance, (ii) an area with tooth loss prior to implant treatment or (iii) a lower wisdom tooth planned for removal. The costs were calculated using an approach based on the identification, measurement and valuation of all resources used in the delivery of the service that combined direct costs (capital equipment, accommodation, labour) with indirect costs (patients' and accompanying persons' time, "out of pocket" costs for examination fee and visits). RESULTS: The estimates for direct and indirect costs varied among the healthcare systems, being highest in Malmö and lowest in Leuven. Variation in direct costs was mainly owing to different capital costs for the CBCT equipment arising from differences in purchase prices (range €148 000-227 000). Variation in indirect costs were mainly owing to examination fees (range €0-102.02). CONCLUSIONS: Cost analysis provides an important input for economic evaluations of diagnostic methods in different healthcare systems and for planning of service delivery. Additionally, it enables decision-makers to separate variations in costs between systems into those due to external influences and those due to policy decisions. A cost evaluation of a dental radiographic method cannot be generalized from one healthcare system to another, but must take into account these specific circumstances.

Development of a clinically applicable tool for bone density assessment.

OBJECTIVES: To assess the accuracy and reliability of new software for radiodensitometric evaluations. METHODS: A densitometric tool developed by MevisLab was used in conjunction with intraoral radiographs of the premolar region in both in vivo and laboratory settings. An aluminum step wedge was utilized for comparison of grey values. After computer-aided segmentation, the interproximal bone between the premolars was assessed in order to determine the mean grey value intensity of this region and convert it to a thickness in aluminum. Evaluation of the tool was determined using bone mineral density (BMD) values derived from decalcified human bone specimens as a reference standard. In vivo BMD data was collected from 35 patients as determined with dual X-ray absorptiometry (DXA). The intra and interobserver reliability of this method was assessed by Bland and Altman Plots to determine the precision of this tool. RESULTS: In the laboratory study, the threshold value for detection of bone loss was 6.5%. The densitometric data (mm Al eq.) was highly correlated with the jaw bone BMD, as determined using dual X-ray absorptiometry (r = 0.96). For the in vivo study, the correlations between the mm Al equivalent of the average upper and lower jaw with the lumbar spine BMD, total hip BMD and femoral neck BMD were 0.489, 0.537 and 0.467, respectively (P < 0.05). For the intraobserver reliability, a Bland and Altman plot showed that the mean difference +/- 1.96 SD were within +/-0.15 mm Al eq. with the mean difference value small than 0.003 mm Al eq. For the interobserver reliability, the mean difference +/-1.96 SD were within +/-0.11 mm Al eq. with the mean difference of 0.008 mm Al eq. CONCLUSIONS: A densitometric software tool has been developed, that is reliable for bone density assessment. It now requires further investigation to evaluate its accuracy and clinical applicability in large scale studies.

Osteoporosis detection using intraoral densitometry.

OBJECTIVES: To determine the diagnostic accuracy of mandibular and maxillary bone density in detecting osteoporosis using receiver operating characteristic (ROC) analysis. METHODS: 671 women between 45 years and 70 years of age underwent dual energy X-ray absorptiometry (DXA) of the hip and lumbar spine. This was the gold standard for diagnosing osteoporosis. Intraoral radiography of the upper and lower right premolar region was performed, using an aluminium wedge as a densitometric reference. Jaw bone density was determined using dedicated software. Observer differences and ROC curves were analysed. RESULTS: For detecting osteoporosis using jaw bone density, the area under the ROC curve (A(z)) was 0.705. For separate analysis of mandibular and maxillary films, sensitivity varied from 33.9% to 38.7% and specificity from 83.5% to 85.3% when using a threshold of 4.3 mm Al equivalent. CONCLUSIONS: Density of the premolar region reaches a fair diagnostic accuracy, which might improve when including additional factors in the analysis and refining the densitometric tool.

Bone density measurements in intra-oral radiographs.

Jaw bone density measurements are applicable in many clinical situations to assess bone tissue. To be able to implement research findings in clinical reality, tools must be simple and low cost. Intra-oral radiographs including a reference material perform well as a densitometric tool. However, the inclusion of a reference material, usually in the form of a metal wedge, is an additional burden for the dentist. The aim of this study was to evaluate whether a reference step wedge is required for accurate densitometric results. Dual energy X-ray absorptiometry measurements and densitometric measurements on intra-oral radiographs using a custom-made software were performed on bone samples from the premolar region of the mandible. Observer agreement of bone density expressed as grey value was high. The correlation between mandibular bone mineral density and the densitometric values on intra-oral radiographs was substantially higher when the aluminium step wedge was included. The Wilcoxon test revealed no significant difference between the density measurements using nine or three steps of the Al reference wedge. Density determination of grey value and mm Aleq thickness value both have good intra- and inter-observer agreement. However, jaw bone densitometry is far more accurate when including a reference wedge.

Accuracy and precision of a densitometric tool for jaw bone.

OBJECTIVES: To develop a digital densitometric tool for jaw bone to analyse intraoral radiographs. To assess precision and accuracy for this tool and determine the minimal detection threshold for density changes. METHODS: Bone samples deriving from the premolar region of 47 human mandibles were selected for analysis. The samples were obtained from adult cadavers in the department of anatomy (Faculty of Medicine, KULeuven) with ethical approval. Digital radiography was performed on all bone samples. Direct volumetric measurements served as gold standard density values and allowed determination of accuracy. Dual-energy X-ray absorptiometry (DXA) scans were performed on all specimens. For all radiographs, density in mm Al eq was calculated using custom-made software, Osteop. Precision and intraobserver and interobserver reliability of this method were assessed. The bone specimens were progressively decalcified. At standard time intervals the percentage of decalcification was calculated. At each decalcification step, radiographs were taken and analysed. RESULTS: CV was always lower than 3%, which points to a good precision of the method. Correlation between the density measurements in mm Al eq and the DXA results was 0.9, for the density measurements in mm Al eq and the direct density measurements r was 0.5. The custom-made software was able to detect a change in bone mineralization of 6.6%. CONCLUSIONS: The present method for bone densitometric analysis offers potentials for clinical evaluation of bone density and minute bone density changes in the jaw bone.

The influence of oral implant-supported prostheses on articulation and myofunction.

The aim of the present research was to assess articulation and myofunction in patients wearing fixed or removable prostheses supported by oral implants. 164 edentulous patients with implant supported prostheses were divided in four subgroups, dependent on their dental status, and compared to control groups of forty five subjects having a natural dentition. More than fifteen articulatory and myofunctional parameters were evaluated. The results showed that subjects with prostheses on implants tend to have more articulation problems than controls. Especially patients with a complete fixed prosthesis on implants in the upper jaw seemed to experience problems pronouncing /s/ and /z/. There also seemed to be influences of age and hearing factors.