Relations between the bone density values from computerized tomography, and implant stability parameters: a clinical study of 230 regular platform implants

Türkyilmaz, Ilser; Tümer, Celal; Ozbek, Esma Nida; Tözüm, Tolga Fikret

doi:10.1111/j.1600-051x.2007.01112.x

Cited by 180 publications

(187 citation statements)

References 25 publications

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“…The average radiographic bone density was measured and the average Hounsfield units values based on four different regions in the mouth ranged from 459 HU to 928 HU. 15 The highest Hounsfield units mean is from the anterior mandible and the lowest Hounsfield units mean is from the posterior maxilla. In another retrospective dental clinical study by Turkyilmaz and McGlumphy,6 implant recipient sites were evaluated with a spiral CT machine (Siemens SomatomH AR-SP 40, Erlanger, Germany).…”

Section: Discussionmentioning

confidence: 95%

Deriving Hounsfield units using grey levels in cone beam CT: a clinical application

Reeves¹,

Mah

McDavid

2012

Dentomaxillofacial Radiology

112

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Objective: To present a clinical study demonstrating a method to derive Hounsfield units from grey levels in cone beam CT (CBCT). Methods: An acrylic intraoral reference object with aluminium, outer bone equivalent material (cortical bone), inner bone equivalent material (trabecular bone), polymethlymethacrylate and water equivalent material was used. Patients were asked if they would be willing to have an acrylic bite plate with the reference object placed in their mouth during a routine CBCT scan. There were 31 scans taken on the Asahi Alphard 3030 (Belmont Takara, Kyoto, Japan) and 30 scans taken on the Planmeca ProMax 3D (Planmeca, Helsinki, Finland) CBCT. Linear regression between the grey levels of the reference materials and their linear attenuation coefficients was performed for various photon energies. The energy with the highest regression coefficient was chosen as the effective energy. The attenuation coefficients for the five materials at the effective energy were scaled as Hounsfield units using the standard Hounsfield units equation and compared to those derived from the measured grey levels of the materials using the regression equation. Results: In general, there was a satisfactory linear relation between the grey levels and the attenuation coefficients. This made it possible to calculate Hounsfield units from the measured grey levels. Uncertainty in determining effective energies resulted in unrealistic effective energies and significant variability of calculated CT numbers. Linear regression from grey levels directly to Hounsfield units at specified energies resulted in greater consistency. Conclusions:The clinical application of a method for deriving Hounsfield units from grey levels in CBCT was demonstrated.

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Section: Discussionmentioning

confidence: 95%

Deriving Hounsfield units using grey levels in cone beam CT: a clinical application

Reeves¹,

Mah

McDavid

2012

Dentomaxillofacial Radiology

112

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“…The main use for density estimations would be in the evaluation of bone tissue before implant placement. Different studies have investigated bone quality based on HU from MSCT scans from implant patients [3,[23][24][25][26][27]. However, there are different terms currently used in literature to denote bone tissue attributes, and there is no standardised definition for terms like bone quantity and quality [28].…”

Section: Discussionmentioning

confidence: 99%

“…However, the superposition of various tissues in 2D radiography is a significant limitation that inhibits an appropriate evaluation of potential implant sites in many cases. Apart from the localisation of various anatomical structures, three-dimensional (3D) radiography can be used for the evaluation of bone tissue characteristics such as width, depth, density and structure [1][2][3]. Different 3D imaging modalities are available for implant planning.…”

mentioning

confidence: 99%

“…Current-generation CBCT scanners allow for linear and volumetric measurements at potential implant sites in the jaw bones at submillimetre accuracy [7][8][9][10][11]. However, there are contradictory reports as to whether CBCT can be used for bone tissue evaluations by means of density estimations [10][11][12][13][14][15][16][17][18][19][20][21][22], similar to the use of Hounsfield units (HU) in MSCT which can be related to absolute density [3,[23][24][25][26][27]. Although most CBCT devices use 12-bit images (i.e.…”

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confidence: 99%

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Variability of dental cone beam CT grey values for density estimations

Pauwels

Nackaerts²,

Bellaiche³

et al. 2013

BJR

126

112

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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 23, 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.

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“…Calculation of densities based on Gray values obtained from CT scans has become easily applicable and correlates well with fastening torque and implant stability values. 1 In CT, Gray values can be calibrated as Hounsfield units (HUs), which are defined as linear transformations of measured X-ray attenuation coefficients of materials with reference to water. 2 The HU scale is based on two fixed values, which are 0 HU for water and 21000 HU for air.…”

Section: Introductionmentioning

confidence: 99%

Ultralow dose dentomaxillofacial CT imaging and iterative reconstruction techniques: variability of Hounsfield units and contrast-to-noise ratio

Widmann

Bischel

Stratis

et al. 2016

BJR

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Objective: The aim of this study was to evaluate whether application of ultralow dose protocols and iterative reconstruction technology (IRT) influence quantitative Hounsfield units (HUs) and contrast-to-noise ratio (CNR) in dentomaxillofacial CT imaging. Methods: A phantom with inserts of five types of materials was scanned using protocols for (a) a clinical reference for navigated surgery (CT dose index volume 36.58 mGy), (b) low-dose sinus imaging (18.28 mGy) and (c) four ultralow dose imaging (4.14, 2.63, 0.99 and 0.53 mGy). All images were reconstructed using: (i) filtered back projection (FBP); (ii) IRT: adaptive statistical iterative reconstruction-50 (ASIR-50), ASIR-100 and model-based iterative reconstruction (MBIR); and (iii) standard (std) and bone kernel. Mean HU, CNR and average HU error after recalibration were determined. Each combination of protocols was compared using Friedman analysis of variance, followed by Dunn's multiple comparison test. Results: Pearson's sample correlation coefficients were all .0.99. Ultralow dose protocols using FBP showed errors of up to 273 HU. Std kernels had less HU variability than bone kernels. MBIR reduced the error value for the lowest dose protocol to 138 HU and retained the highest relative CNR. ASIR could not demonstrate significant advantages over FBP. Conclusions: Considering a potential dose reduction as low as 1.5% of a std protocol, ultralow dose protocols and IRT should be further tested for clinical dentomaxillofacial CT imaging. Advances in knowledge: HU as a surrogate for bone density may vary significantly in CT ultralow dose imaging. However, use of std kernels and MBIR technology reduce HU error values and may retain the highest CNR.

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Relations between the bone density values from computerized tomography, and implant stability parameters: a clinical study of 230 regular platform implants

Abstract: The bone density values from pre-operative CT examination may provide an objective assessment of bone quality, and significant correlations between bone density and implant stability parameters may help clinicians to predict primary stability before implant insertion.

Cited by 180 publications

References 25 publications

Deriving Hounsfield units using grey levels in cone beam CT: a clinical application

Deriving Hounsfield units using grey levels in cone beam CT: a clinical application

Variability of dental cone beam CT grey values for density estimations

Ultralow dose dentomaxillofacial CT imaging and iterative reconstruction techniques: variability of Hounsfield units and contrast-to-noise ratio

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