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 Table of Contents  
ORIGINAL ARTICLE
Year : 2019  |  Volume : 8  |  Issue : 14  |  Page : 75-83

A comparative evaluation of the role of cone beam computed tomography (CBCT) imaging and orthopantomography (OPG) in sinus augmentation procedures: An original study


1 Department of Oral and Maxillofacial Surgery, D.A.P.M.R.V. Dental College and Hospital, Bengaluru, Karnataka, India
2 Department of Oral Medicine and Radiology, Saraswati-Dhanwantari Dental College and Hospital and Postgraduate Research Institute, Parbhani, Maharashtra, India

Date of Submission01-Mar-2017
Date of Acceptance01-Jun-2018
Date of Web Publication04-Oct-2019

Correspondence Address:
Dr. Abhishek Singh Nayyar
44, Behind Singla Nursing Home, New Friends' Colony, Model Town, Panipat - 132 103, Haryana
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/nnjcr.nnjcr_8_17

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  Abstract 


Background and Aim: Radiology and higher imaging modalities have their own advantages and disadvantages. The present study was designed to do a comparative analysis of the role of cone-beam computed tomography (CBCT) and orthopantomography (OPG) for preoperative planning and postoperative evaluation of treatment outcomes in implant therapy in combination with sinus augmentation procedures. Materials and Methods: Pre- and postoperative assessment of maxillary sinuses was done in 17 patients who underwent implant therapy in combination with sinus augmentation procedures using CBCT and OPG. Statistical analysis was performed using IBM SPSS statistics 20 (Chicago, USA). Paired and unpaired t-tests were used to do a comparative analysis of the two modalities used. Results: There was a concordance between the treatment type based on pre- and postoperative CBCT assessments. The assessment of sinus morphology revealed a significantly higher detection rate of aberrations in the form of sinus mucosal hypertrophy and septa on CBCT which were imperceptible on orthopantomographs undermining the role of routine radiography in these procedures. The results obtained, also, revealed that vertical alveolar bone height could be measured more precisely with CBCT. Conclusion: Based on the findings of the above study, it could be concluded that CBCT increased the accuracy of both the sinus morphology assessment and the estimation of gain in vertical alveolar bone height, in addition to bone density, which remains unassessed by the conventional radiological techniques including OPG.

Keywords: Cone-beam computed tomography, imaging, maxillary sinus, orthopantomography, radiography, sinus augmentation


How to cite this article:
Rao S G, Mehta S, Nayyar AS. A comparative evaluation of the role of cone beam computed tomography (CBCT) imaging and orthopantomography (OPG) in sinus augmentation procedures: An original study. N Niger J Clin Res 2019;8:75-83

How to cite this URL:
Rao S G, Mehta S, Nayyar AS. A comparative evaluation of the role of cone beam computed tomography (CBCT) imaging and orthopantomography (OPG) in sinus augmentation procedures: An original study. N Niger J Clin Res [serial online] 2019 [cited 2019 Dec 5];8:75-83. Available from: http://www.mdcan-uath.org/text.asp?2019/8/14/75/268538




  Introduction Top


Diagnostic imaging is an integral part of dental implant therapy for preoperative planning and postoperative evaluation of treatment outcomes by use of various imaging techniques. Intraoral radiography, although easily available and relatively inexpensive, is not considered satisfactory in giving reliable information regarding the anatomy of the region due to its major constraints of overlapping and superimpositions. Geometric and anatomic limitations in the form of the measurements which change with a change in the angulations used during the exposure of the radiographs are added disadvantages. Regarding orthopantomography (OPG), despite being with an advantage of a panoramic view of the maxillofacial structures in a single view, lack of image sharpness and resolution, apart from unequal magnification and geometric distortion, which are the major constraints in panoramic radiography, the other name for OPG, often lead to an inaccurate interpretation and measurements.[1] Although computed tomography (CT) is superior as it gives three-dimensional, multiplanar reformatted images, with no superimposition of anatomic structures and with a high contrast and resolution, it is associated with relatively higher radiation exposure, cost, high footprint, and difficulty in accessibility. Hence, cone-beam CT (CBCT) was developed with distinct advantages in the form of reasonably low levels of radiation exposure and higher resolution than the conventional CT. CBCT uses a round or rectangular, cone-shaped X-ray beam centered on a two-dimensional X-ray sensor to scan a 360° rotation around the patient's head. During the scan, a series of 360 exposures or projections, one for each degree of rotation, is acquired which provides the raw data for the final image reconstruction with the help of computer software. Multiplanar reformatting of the primary reconstruction allows for both three- and two-dimensional images in any selected plane required. Furthermore, CBCT has shown to be authentic and a good indicator of regenerated bone, pre- and postprocedures, for easy comparisons.[1],[2] Various studies have concluded that CBCT imaging should be recommended for planning sinus augmentation procedures;[3] however, there is a dearth of studies regarding the comparison between CBCT and OPG for planning sinus augmentation procedures before implant placement in the literature. The present study was designed to do a comparative analysis of the role of CBCT and OPG for preoperative planning and postoperative evaluation of treatment outcomes in implant therapy in combination with sinus augmentation procedures.


  Materials and Methods Top


The present prospective, case control study was carried out on 17 patients seeking implant options for oral rehabilitation. The total sites operated were 20 including 10 sites for direct and 10 sites of indirect procedures (n = 20, 10 direct and 10 indirect). Three patients had 2 sites each where the required surgical procedure was carried out on each side, right and left, in the maxillary arch. So, 3 patients with 2 sites, each translated to 6 sites and the remaining 14 patients with one site each, either on the right or, left side, translated to 14 sites, making a total of 20 sites in 17 patients. The study was carried out in a specified time period and the enrolment was done based on the time period of the study. The patients who met with the defined inclusion and exclusion criteria and who reported within the said time frame were enrolled for the procedures. Patients under 18 years of age, those who presented with sinus pathology, previous sinus surgeries, chronic smokers and who were suffering from any systemic illnesses and/or, infectious diseases or, who were immuno-compromised and with medical conditions like uncontrolled diabetes mellitus and hemorrhagic diseases, patients on steroid therapy and patients who were not willing to participate in the study were excluded from the study. Sinus augmentation procedures were carried out in patients satisfying the defined inclusion and exclusion criteria requiring placement of implants in atrophic maxilla. Treatment planning was done based on the accuracy of the sinus morphology assessment obtained on imaging. Indirect sinus augmentation was carried out in patients with a bone height of <9 mm while patients with bone height of <5 mm were taken-up for direct sinus augmentation procedure. The period of edentulousness varied from 6 months to 12 months. The patients included in the study were informed about the details of the study including the use of the synthetic graft material and a written informed consent was obtained. The research protocol was approved by the Institutional Ethics Committee governing the use of human subjects in clinical research. A detailed case history was taken including chief complaint, history of presenting illness and medical and personal histories. A thorough clinical examination, including systemic and regional examination, was done. Pre-and post-operative assessment of maxillary sinuses was done using CBCT and orthopantomography. Treatment planning was done based on the accuracy of the sinus morphology assessment obtained on imaging. Apically tapered, commercially pure titanium implants (Life Care Devices Private Limited Mahim, West Mumbai, India) were used for patients undergoing indirect sinus augmentation. The length of implant was 8, 10, and 11.5 with diameters of 3.5, 4.0, and 5 mm respectively. Patients in the category of direct augmentation underwent the lateral approach procedure and augmentation with an alloplastic graft material. Implant placement was done after 6 months as the second stage procedure. The patients were assessed clinically at immediate post-operatively, and at 1 week, 1 month, 3 months, and 6 months post-operatively. Radiographic assessment for alveolar bone height was done pre-operatively and at 6 months post-operatively using cone beam computed tomography (CBCT) and orthopantomography (OPG). Orthopantomographs (screening tool) were taken to rule-out other pathologies and as a part of initial assessment. CBCT scans were assessed for pre-operative and post-operative bone height, bone width and bone density. The CBCT scans were obtained from Kodak 9300 which is a hybrid machine using a CS3D imaging software and flap panel detector sensor with exposure parameters of 90 KVp and 10 mA and resolution of 90 microns. The cross-sections were made 1mm apart [Figure 1]a, [Figure 1]b, [Figure 1]c, [Figure 1]d, [Figure 1]e, [Figure 1]f, [Figure 2] and [Figure 3]a, [Figure b]. The bone height measured pre-operatively using CBCT considered the pre-operative bone height as a measurement taken from the crest of the ridge till the sinus floor and post-operatively, from the crest till hyper-density evident apically. These measurements were standardized as a computer software drawing tool was used. Bone width was taken as the bucco-palatal width at three intervals- at the crest, 3 mm from the crest and 6 mm from the crest. Bone density was assessed visually by assessing the width of the trabecular pattern and was classified based on Misch's classification.[4] Another additional bone density tool used was the pixel values (the gray scale values) obtained on the CBCT scan, although not reliable, and comparison done pre-operatively and post-operatively. The pixel values contained were a mean of three measurements obtained along the residual bone corresponding with the bone width levels. Statistical analysis was done using IBM SPSS statistics 20 (Chicago, USA). Paired and Unpaired t-tests were used to do a comparative analysis of the two modalities, CBCT and OPG, in the assessment of sinus morphology as well as to compare the pre- and post-operative variables obtained.
Figure 1: (a-f) Routine sequential cone-beam computed tomography scans; (a and b) axial sections; (c) cross section; (d) oblique sagittal section; (e) 3-D reconstruction; (f) width measurement

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Figure 2: Axial section of cone-beam computed tomography showing sinus septa

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Figure 3: (a and b) Axial sections of cone-beam computed tomography showing sinus mucosal thickening

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Cases done with pre-operative CBCT evaluations (only 4 representative cases are being discussed to avoid repetition)

Case Report 1

With a pre-operative residual bone height of 0.8 mm in 16 region and 1.5 mm in 17 region, direct sinus augmentation was carried-out in a 40 year old male patient followed by implant placement of 3.75 mm × 11.5 mm dimensions as a single step procedure. Lateral window was created and synthetic graft material was dispensed through the lateral osteotomy site to maintain the elevated sinus membrane followed by placement of two dental implants through crestal approach under local anesthesia and strict aseptic protocols. At the end of 6 months, a CBCT scan was advised to evaluate the increase in bone height which was 11 mm and 10.8 mm in 16 and 17 region respectively [Figure 4] and [Figure 5].
Figure 4: Preoperative orthopantomograph and cross sections of cone-beam computed tomography showing residual alveolar bone height

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Figure 5: Postoperative orthopantomograph and cross sections of cone-beam computed tomography showing an increase in residual alveolar bone height

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Case Report 2

A 45 year old patient with a residual bone height of 6.6 mm in 17 region underwent procedure of indirect sinus elevation using sinus osteotomy in relation to 17 region. Synthetic graft material was dispensed through the crestal osteotomy site to maintain the elevated sinus membrane followed by placement of a dental implant measuring 5 mm × 10 mm under local anesthesia and strict aseptic protocols. The implant was allowed to osseo-integrate for a period of six months during which the patient was followed periodically and was assessed for peri-implantitis, crestal bone loss and mobility. At the end of 6 months, a CBCT scan was advised to evaluate the increase in bone height which was 12 mm [Figure 6] and [Figure 7].
Figure 6: Preoperative orthopantomograph and cross section of cone-beam computed tomography showing residual alveolar bone height

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Figure 7: Postoperative orthopantomograph and cross section of cone-beam computed tomography showing residual alveolar bone height

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Case Report 3

A 75 year old male patient reported to the unit seeking options for replacement of his missing upper right first molar with fixed prosthesis. Due to the residual bone height of 5.3 mm, the patient was advised and subsequently, underwent the procedure of indirect sinus elevation using sinus osteotomy in relation to 16 region followed by placement of a dental implant measuring 5 mm × 10 mm under local anesthesia and strict aseptic protocols. The implant was allowed to osseo-integrate for a period of six months during which the patient was followed periodically. At the end of 6 months, a CBCT scan showed an increase in bone height to 11.5 mm [Figure 8].
Figure 8: Pre- and postoperative orthopantomographs and cross sections of cone-beam computed tomography showing residual alveolar bone height

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Case Report 4

A 19 year old young female patient was referred to Department seeking options for rehabilitation of missing right upper first molar with fixed prosthesis as she was uncomfortable with the removable partial denture in relation to 16. The residual bone height was 4 mm in 16 tooth region. Patient was taken-up for direct sinus elevation via lateral window approach for sinus augmentation in relation to 16. Under aseptic conditions and local anesthesia, lateral wall of maxilla was exposed after muco-periosteal flap elevation. A window was created of 1cm diameter corresponding to apical aspect of 16. Sinus membrane was identified and elevated using sinus elevators and reamers without perforating the lining. Once the sinus membrane was elevated, graft material was dispensed to achieve an augmentation of 1cm assessed clinically and confirmed using post-operative OPG. At the end of 6 months, a CBCT scan showed an increased bone height of 12.7 mm [Figure 9].
Figure 9: Pre- and postoperative orthopantomographs and cross sections of cone-beam computed tomography showing residual alveolar bone height

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  Results Top


The study comprised 43% females and 57% males with a mean age of 46.07 years. The study included 9 males and 8 females. The gender distribution in the indirect sinus augmentation procedures was 4 males and 6 females while direct sinus augmentation was done in 6 males and 3 females. Two patients (one male and one female) underwent both direct sinus augmentation and indirect sinus augmentation on their right and left maxillary quadrants and one female underwent direct technique on both sides. The region of sinus augmentation varied from premolar to molar region, with the majority of it being in the 1st molar region. In indirect sinus augmentation procedure, as measured by CBCT, the average preoperative height of bone was 6.80 mm while postoperative height of bone was 11.86 mm. A paired sample t-test was conducted to know the difference in pre- and posttreatment measurements of bone height with indirect sinus augmentation procedure. The posttreatment bone height (11.86 ± 1.11) was significantly higher than pretreatment bone height (6.80 ± 0.70) (t = 12.90, P < 0.005) [Table 1] and [Graph 1]. In direct sinus augmentation procedure, the average preoperative height of bone was 2.44 mm while postoperative height of bone was 11.27 mm. When a paired sample t-test was conducted to know the difference in pre- and posttreatment measurements of bone height with direct sinus augmentation, it showed that the posttreatment bone height (11.27 ± 0.71) was significantly higher than pretreatment bone height (2.44 ± 0.81) (t = 32.17, P < 0.005) [Table 2] and [Graph 2]. In indirect sinus augmentation procedure, as measured by OPG, the average preoperative height of bone was 7.20 mm while postoperative height of bone was 10.20 mm. A paired sample t-test was conducted to know the difference in pre- and posttreatment measurements of bone height with indirect sinus augmentation procedure. The posttreatment bone height (10.20 ± 0.92) was significantly higher than pretreatment bone height (7.20 ± 1.23) (t = 10.06, P < 0.005) [Table 3] and [Graph 3]. In direct sinus augmentation procedure, the average preoperative height of bone, as measured by OPG, was 1.30 mm while postoperative height of bone was 8.85 mm. When a paired sample t-test was conducted to know the difference in pre- and posttreatment measurements of bone height with direct sinus augmentation, it showed that the posttreatment bone height (8.85 ± 1.0) was significantly higher than pretreatment bone height (1.30 ± 0.92) (t = 19.33, P < 0.005) [Table 4] and [Graph 4]. When a comparison was done in the assessment of mean preoperative height of bone in the indirect sinus augmentation procedure as measured by CBCT and OPG, the average preoperative height of bone was 6.80 ± 0.70 in case of CBCT while 7.20 ± 1.23 in case of OPG. When a paired sample t-test was conducted to know the difference in pretreatment measurements of bone height with indirect sinus augmentation in case of CBCT and OPG, it showed P = 0.173, which was not statistically significant [Table 5] and [Graph 5]. When a comparison was done in the assessment of mean postoperative height of bone in the indirect sinus augmentation procedure as measured by CBCT and OPG, the average postoperative height of bone was 11.86 ± 1.11 in case of CBCT while 10.20 ± 0.92 in case of OPG. When a paired sample t-test was conducted to know the difference in posttreatment measurements of bone height with indirect sinus augmentation in case of CBCT and OPG, it showed P < 0.005, which was statistically significant [Table 6] and [Graph 6]. When a comparison was done in the assessment of mean preoperative height of bone in the direct sinus augmentation procedure as measured by CBCT and OPG, the average preoperative height of bone was 2.44 ± 0.81 in case of CBCT while 1.30 ± 0.92 in case of OPG. When a paired sample t-test was conducted to know the difference in pretreatment measurements of bone height with indirect sinus augmentation in case of CBCT and OPG, it showed P < 0.005, which was statistically significant [Table 7] and [Graph 7]. When a comparison was done in the assessment of mean postoperative height of bone in the direct sinus augmentation procedure as measured by CBCT and OPG, the average postoperative height of bone was 11.27 ± 0.71 in case of CBCT while 8.85 ± 1.00 in case of OPG. When a paired sample t-test was conducted to know the difference in posttreatment measurements of bone height with indirect sinus augmentation in case of CBCT and OPG, it showed P < 0.005, which was statistically significant [Table 8] and [Graph 8].
Table 1: Comparison of mean pre- and postoperative bone height (mm) with indirect sinus augmentation as measured by cone-beam computed tomography

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Table 2: Comparison of mean pre- and postoperative bone height (mm) with direct sinus augmentation as measured by cone-beam computed tomography

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Table 3: Comparison of mean pre- and postoperative bone height (mm) with indirect sinus augmentation as measured by orthopantomography

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Table 4: Comparison of mean pre-and postoperative bone height (mm) with direct sinus augmentation as measured by orthopantomography

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Table 5: Comparison of mean preoperative bone height (mm) with indirect sinus augmentation as measured by orthopantomography and cone-beam computed tomography

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Table 6: Comparison of mean postoperative bone height (mm) with indirect sinus augmentation as measured by orthopantomography and cone-beam computed tomography

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Table 7: Comparison of mean preoperative bone height (mm) with direct sinus augmentation as measured by orthopantomography and cone-beam computed tomography

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Table 8: Comparison of mean postoperative bone height (mm) with direct sinus augmentation as measured by orthopantomography and cone-beam computed tomography

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  Discussion Top


Radiographic evaluation is necessary for information regarding the quantity and quality of the bone available and to localize anatomic structures in the proximity of the region where the procedure is supposed to be carried out. Pre-surgical implant imaging should provide information about the implant site with regards to the osseous morphology. Cross-sectional imaging is required to obtain such information regarding the osseous morphology in terms of the relative proportion and densities of the cortical and medullary bones for implant site assessment. Furthermore, since the position of the maxillary sinus floor is difficult to be assessed on two-dimensional imaging and as cone beam computed tomography (CBCT) has numerous advantages over the conventional radiography as well as computed tomography (CT), CBCT was used in the present study for carrying-out the intended sinus augmentation procedures while bone density was assessed visually by assessing the width of the trabecular pattern and was classified based on Misch's classification.[4] This was in accordance with the study conducted by Temmerman et al in 2011 which showed that panoramic imaging underscored the mesio-distal distance of the available bone in upper premolar region and concluded the need for going for cross-sectional imaging like CBCT for pre-surgical treatment planning.[3] Arias-Irimia et al. obtained a significant positive correlation between the volume of the sinus augmentation required and the size of the bone graft to be used (height and width) based on the predictions made preoperatively using CBCT imaging.[5] According to Baciut et al., CBCT increased the accuracy of both assessment of sinus morphology and harvesting of bone grafts in line with the estimated volume available.[6] Soardi et al. did a quantitative comparison of CBCT and microradiography in the evaluation of bone density after sinus augmentation procedures in patients having crestal bone height <2 mm and concluded that CBCT imaging had a clear predictability in treatment planning.[7] Rodriguez-Recio et al. showed the benefits of using CT and a specialized software that could provide significant information regarding the quality and quantity of bone in the donor areas.[8] Buyukkurt et al. showed that three-dimensional CT techniques could be used accurately to calculate the volume required for sinus augmentation procedures.[9] Numerous other studies have, also, shown the advantages of using CT in providing important volumetric information about the quality and quantity of bone in the said procedures.[10],[11] The present study was designed to do a comparative analysis of the role of CBCT and OPG for preoperative planning and postoperative evaluation of treatment outcomes in implant therapy in combination with sinus augmentation procedures. The results obtained from the present study proved that using a specialized software, CBCT allowed the estimation of sinus morphology as well as the estimation of gain in vertical alveolar bone height, in addition to bone density, significantly better than the panoramic radiography.


  Conclusion Top


Radiology and imaging play an important role in any minor or major surgical procedure including the implant placement procedures. An accurate presurgical planning, based on adequately selected radiology and imaging techniques, ensures optimal treatment outcomes from the planned surgical procedures. By bringing new and detailed information through cross-sectional imaging and three-dimensional assessment of the region in the presurgical phase of treatment, advanced imaging modalities including CBCT may change treatment planning for the various sinus augmentation procedures perfomed in cases with atrophic maxillae and in the presence of numerous other anatomic constraints. Based on the findings of the above study, it could be concluded that CBCT increased the accuracy of both the sinus morphology assessment and the estimation of gain in vertical alveolar bone height, in addition to bone density, which remains unassessed by the conventional radiological techniques including OPG.

Acknowledgment

We would like to acknowledge all the patients who contributed for the study.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
  References Top

1.
Chan HL, Misch K, Wang HL. Dental imaging in implant treatment planning. Implant Dent 2010;19:288-98.  Back to cited text no. 1
    
2.
White SC, Pharoah MJ. Oral Radiology. Principles and Interpretation. 5th ed. St Louis: Mosby; 2004.  Back to cited text no. 2
    
3.
Temmerman A, Hertelé S, Teughels W, Dekeyser C, Jacobs R, Quirynen M, et al. Are panoramic images reliable in planning sinus augmentation procedures? Clin Oral Implants Res 2011;22:189-94.  Back to cited text no. 3
    
4.
Misch CE. Contemporary Implant Dentistry. 3rd ed. St Louis, Missouri: Mosby Elsevier; 2008.  Back to cited text no. 4
    
5.
Arias-Irimia O, Barona-Dorado C, Martínez-Rodríguez N, Ortega-Aranegui R, Martínez-González JM. Pre-operative evaluation of the volume of bone graft in sinus lifts by means of compuDent. Med Oral Patol Oral Cir Bucal 2010;15:e512-6.  Back to cited text no. 5
    
6.
Baciut M, Hedesiu M, Bran S, Jacobs R, Nackaerts O, Baciut G, et al. Pre – And postoperative assessment of sinus grafting procedures using cone-beam computed tomography compared with panoramic radiographs. Clin Oral Implants Res 2013;24:512-6.  Back to cited text no. 6
    
7.
Soardi CM, Zaffe D, Motroni A, Wang HL. Quantitative comparison of cone beam computed tomography and microradiography in the evaluation of bone density after maxillary sinus augmentation: A preliminary study. Clin Implant Dent Relat Res 2014;16:557-64.  Back to cited text no. 7
    
8.
Rodriguez-Recio O, Rodriguez-Recio C, Gallego L, Junquera L. Computed tomography and computer-aided design for locating available palatal bone for grafting: Two case reports. Int J Oral Maxillofac Implants 2010;25:197-200.  Back to cited text no. 8
    
9.
Buyukkurt MC, Tozoglu S, Yavuz MS, Aras MH. Simulation of sinus floor augmentation with symphysis bone graft using three-dimensional computerized tomography. Int J Oral Maxillofac Surg 2010;39:788-92.  Back to cited text no. 9
    
10.
Liang X, Jacobs R, Hassan B, Li L, Pauwels R, Corpas L, et al. Acomparative evaluation of cone beam computed tomography (CBCT) and multi-slice CT (MSCT) part I. On subjective image quality. Eur J Radiol 2010;75:265-9.  Back to cited text no. 10
    
11.
Liang X, Lambrichts I, Sun Y, Denis K, Hassan B, Li L, et al. Acomparative evaluation of cone beam computed tomography (CBCT) and multi-slice CT (MSCT). Part II: On 3D model accuracy. Eur J Radiol 2010;75:270-4.  Back to cited text no. 11
    


    Figures

  [Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6], [Figure 7], [Figure 8], [Figure 9]
 
 
    Tables

  [Table 1], [Table 2], [Table 3], [Table 4], [Table 5], [Table 6], [Table 7], [Table 8]



 

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