x-Ray

Damstra J, Fourie Z, Huddleston Slater JJ, Ren Y
Department of Orthodontics, University Medical Center Groningen, University of Groningen, PO Box 30.001, Groningen, 9700 RB, The Netherlands
Am J Orthod Dentofacial Orthop. 2010 Jan;137(1):16.e1-6; discussion 16-7, 1/1/2010

The aims of this study were to determine the linear accuracy of 3-dimensional surface models derived from a commercially available cone-beam computed tomography (CBCT) dental imaging system and volumetric rendering software and to investigate the influence of voxel resolution on the linear accuracy of CBCT surface models.

© PMID: 20122425 [PubMed]

Damstra J, Fourie Z, Huddleston Slater JJ, Ren Y
Department of Orthodontics, University Medical Center Groningen, University of Groningen, PO Box 30.001, Groningen, 9700 RB, The Netherlands
Am J Orthod Dentofacial Orthop. 2010 Jan;137(1):16.e1-6; discussion 16-7, 1/1/2010

INTRODUCTION: The aims of this study were to determine the linear accuracy of 3-dimensional surface models derived from a commercially available cone-beam computed tomography (CBCT) dental imaging system and volumetric rendering software and to investigate the influence of voxel resolution on the linear accuracy of CBCT surface models. METHODS: Glass sphere markers were fixed on 10 dry mandibles. The mandibles were scanned with 0.40 and 0.25 voxel size resolutions in 3 sessions. Anatomic truth was established with 6 direct digital caliper measurements. The surface models were rendered by a volumetric rendering program, and the CBCT measurements were established as the mean of the 3 measurements. RESULTS: The intraclass correlation coefficients between the physical measurements and the measurements of the CBCT images of 0.40 and 0.25 voxels were all more than 0.99. All CBCT measurements were accurate. There was no difference between the accuracy of the measurements between the 0.40 and 0.25 voxel size groups. The smallest detectable differences of the CBCT measurements were minimal, confirming the accuracy of the CBCT measurement procedure. CONCLUSIONS: The measurements on 3-dimensional surface models of 0.25 and 0.40 voxel size data sets made with the 3D eXam CBCT scanner (KaVo Dental GmbH, Bismarckring, Germany) and SimPlant Ortho Pro software (version 2.00, Materialise Dental, Leuven, Belgium) are accurate compared with direct caliper measurements. An increased voxel resolution did not result in greater accuracy of the surface model measurments.

© PMID: 20122425 [PubMed]

Hassan B, Metska ME, Ozok AR, van der Stelt P, Wesselink PR
Department of Oral and Maxillofacial Radiology, Academic Centre for Dentistry Amsterdam, Amsterdam, The Netherlands
J Endod. 2010 Jan;36(1):126-9, 1/1/2010

This study compared the accuracy of cone beam computed tomography (CBCT) scans made by five different systems in detecting vertical root fractures (VRFs). It also assessed the influence of the presence of root canal filling (RCF), CBCT slice orientation selection, and the type of tooth (premolar/molar) on detection accuracy.

© PMID: 20003950 [PubMed - indexed for MEDLINE]

Hassan B, Metska ME, Ozok AR, van der Stelt P, Wesselink PR
Department of Oral and Maxillofacial Radiology, Academic Centre for Dentistry Amsterdam, Amsterdam, The Netherlands
J Endod. 2010 Jan;36(1):126-9, 1/1/2010

INTRODUCTION: This study compared the accuracy of cone beam computed tomography (CBCT) scans made by five different systems in detecting vertical root fractures (VRFs). It also assessed the influence of the presence of root canal filling (RCF), CBCT slice orientation selection, and the type of tooth (premolar/molar) on detection accuracy. METHODS: Eighty endodontically prepared teeth were divided into four groups and placed in dry mandibles. The teeth in groups Fr-F and Fr-NF were artificially fractured; those in groups control-F and control-NF were not. Groups Fr-F and control-F were root filled. CBCT scans were made using five different commercial CBCT systems. Two observers evaluated images in axial, coronal, and sagittal reconstruction planes. RESULTS: There was a significant difference in detection accuracy among the five systems (p = 0.00001). The presence of RCF did not influence sensitivity (p = 0.16), but it reduced specificity (p = 0.003). Axial slices were significantly more accurate than sagittal and coronal slices (p = 0.0001) in detecting VRF in all systems. Significantly more VRFs were detected among molars than premolars (p = 0.0001). CONCLUSIONS: RCF presence reduced specificity in all systems (p = 0.003) but did not influence accuracy (p = 0.79) except in one system (p = 0.012). Axial slices were the most accurate in detecting VRFs (p = 0.0001).

© PMID: 20003950 [PubMed - indexed for MEDLINE]

Dr. Gisela Peters
Dental Magazin, 2009;28(6);545 , 1/1/2010

Der diagnostische Nutzen eines DVT-Gerätes liegt in der dreidimensionalen Darstellung der Bil-der. Ist es für niedergelassene Zahnärzte finanzierbar und wirtschaftlich, in der Praxis ein eigenes Gerät zu haben? Ein Bericht zu Kosten, Nutzen und Wirtschaftlichkeit.

© 2010 Deutscher Ärzte-Verlag

Dr. Gisela Peters
Dental Magazin, 2009;28(6);545 , 1/1/2010

Der diagnostische Nutzen eines DVT-Gerätes liegt in der dreidimensionalen Darstellung der Bil-der. Ist es für niedergelassene Zahnärzte finanzierbar und wirtschaftlich, in der Praxis ein eigenes Gerät zu haben? Ein Bericht zu Kosten, Nutzen und Wirtschaftlichkeit.

© 2010 Deutscher Ärzte-Verlag

Theodorakou C, Horner K, Howard K, Walker A
North Western Medical Physics, The Christie NHS Foundation Trust, School of Dentistry, University of Manchester, Manchester, United Kingdom
9/12/2009

Cone beam computed tomography (CBCT) is an x-ray emerging technology with wide applications in the dental and maxillofacial disciplines. Dental CBCT has been associated with higher radiation risk to the patients compared to conventional dental x-ray imaging.

World Congress on Medical Physics and Bioengineering, Munich, 7-12 September 2009 (Conference Paper and poster presentation)

Theodorakou C, Horner K, Howard K, Walker A
North Western Medical Physics, The Christie NHS Foundation Trust, School of Dentistry, University of Manchester, Manchester, United Kingdom
9/12/2009

Cone beam computed tomography (CBCT) is an x-ray emerging technology with wide applications in the dental and maxillofacial disciplines. Dental CBCT has been associated with higher radiation risk to the patients compared to conventional dental x-ray imaging. Several studies have investigated the radiation doses involved in dental CBCT for adults but none has looked into paediatric doses. This study estimates the organ and effective doses to two paediatric tissue-equivalent phantoms using thermoluminescent dosimeters for three dental CBCT units and six imaging protocols. The doses to the thyroid, salivary glands and brain ranged from 0.068mSv to 1.131mSv, 0.708mSv to 2.009mSv and 0.031mSv to 1.584mSv respectively. The skin and red bone marrow have received much lower doses than the other three organs. The effective doses ranged from 0.022 mSv to 0.081 mSv. The highest effective dose was calculated for the NewTom VG using the dental protocol and the lowest was observed for the Next Generation i-CAT using the 6cm maxilla protocol. The effective doses calculated in this study were much higher than these of panoramic x-ray imaging but lower than conventional CT.

World Congress on Medical Physics and Bioengineering, Munich, 7-12 September 2009 (Conference Paper and poster presentation)

Ludlow JB, Ivanovic M
Department of Diagnostic Sciences and General Dentistry, University of North Carolina School of Dentistry, Chapel Hill, North Carolina 27599-7450, USA
Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2008 Jul;106(1):106-14, 7/1/2008

This study compares 2 measures of effective dose, E(1990) and E(2007), for 8 dentoalveolar and maxillofacial cone-beam computerized tomography (CBCT) units and a 64-slice multidetector CT (MDCT) unit.

© PMID: 18504152 [PubMed - indexed for MEDLINE]

Ludlow JB, Ivanovic M
Department of Diagnostic Sciences and General Dentistry, University of North Carolina School of Dentistry, Chapel Hill, North Carolina 27599-7450, USA
Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2008 Jul;106(1):106-14, 7/1/2008

OBJECTIVES: This study compares 2 measures of effective dose, E(1990) and E(2007), for 8 dentoalveolar and maxillofacial cone-beam computerized tomography (CBCT) units and a 64-slice multidetector CT (MDCT) unit. STUDY DESIGN: Average tissue-absorbed dose, equivalent dose, and effective dose were calculated using thermoluminescent dosimeter chips in a radiation analog dosimetry phantom. Effective doses were derived using 1990 and the superseding 2007 International Commission on Radiological Protection (ICRP) recommendations. RESULTS: Large-field of view (FOV) CBCT E(2007) ranged from 68 to 1,073 microSv. Medium-FOV CBCT E(2007) ranged from 69 to 560 microSv, whereas a similar-FOV MDCT produced 860 microSv. The E(2007) calculations were 23% to 224% greater than E(1990). CONCLUSIONS: The 2007 recommendations of the ICRP, which include salivary glands, extrathoracic region, and oral mucosa in the calculation of effective dose, result in an upward reassessment of fatal cancer risk from oral and maxillofacial radiographic examinations. Dental CBCT can be recommended as a dose-sparing technique in comparison with alternative medical CT scans for common oral and maxillofacial radiographic imaging tasks.

© PMID: 18504152 [PubMed - indexed for MEDLINE]