Home Ahead of print Instructions
About us Current issue Subscribe
Editorial board Archives Contact us
Search Submit article Login 
Print this page Email this page


 
 Table of Contents  
ORIGINAL ARTICLE
Year : 2022  |  Volume : 19  |  Issue : 2  |  Page : 101-106

A single-center detection of adult patients with advanced periodontal disease using surgical assessment and cone-beam computed tomography


1 Department of Oral and Maxillofacial Surgery, Sathyabama Dental College and Hospital, Chennai, Tamil Nadu, India
2 Department of Conservative Dentistry and Endodontics, Saraswati Dhanwantari Dental College and Hospital and Post-Graduate Research Institute, Parbhani, Maharashtra, India
3 Department of Preventive Dental Sciences, College of Dentistry, Prince Sattam Bin Abdulaziz University, Al-Kharj, Kingdom of Saudi Arabia
4 Department of Restorative Dental Sciences, College of Dentistry, Majmaah University, Al Majma'ah, Kingdom of Saudi Arabia
5 Division of Periodontology, Department of Preventive Dental Sciences, College of Dentistry, University of Ha'il, Ha'il, Kingdom of Saudi Arabia
6 Department of Oral Medicine and Radiology, Saraswati Dhanwantari Dental College and Hospital and Post-Graduate Research Institute, Parbhani, Maharashtra, India

Date of Submission27-Nov-2021
Date of Decision02-Mar-2022
Date of Acceptance14-Mar-2022
Date of Web Publication23-Nov-2022

Correspondence Address:
Khalid Gufran
Department of Preventive Dental Sciences, College of Dentistry, Prince Sattam Bin Abdulaziz University, Al-Kharj
Kingdom of Saudi Arabia
Login to access the Email id

Source of Support: None, Conflict of Interest: None


DOI: 10.4103/njbcs.njbcs_66_21

Rights and Permissions
  Abstract 


Context: One of the major limitations of conventional radiological procedures is the presence of considerable overlapping and lack of clear, three-dimensional information. Cone-beam computed tomography (CBCT) has emerged as an effective imaging modality in such situations offering high-quality images and lower radiation exposure to patients. Aim: The aim of the present study was to assess the role of CBCT in the detection of intra-bony defects in patients with advanced periodontal disease. Settings and Design: The present study was designed as a prospective, observational study wherein patients aged between 35–55 years with advanced periodontal disease who were indicated for periodontal treatment in form of periodontal surgeries were selected from the outpatient department (OPD) based on defined inclusion and exclusion criteria. Materials and Methods: Sixty patients with chronic periodontitis with 12 teeth each including 6 anterior and 6 posterior teeth were selected for making measurements pre- and peri-operatively while bone defects were measured first with the help of CBCT software installed in an individualized system devised to be used for storing and analyzing CBCT images and then, during surgical intervention using standardized UNC-15 periodontal probe and compared. Statistical Analysis Used: Statistical analysis was performed using SPSS version 18.0 (SPSS Inc., Chicago, IL, USA). The measurements obtained with the help of CBCT software installed in the personalized system and those obtained on surgical exploration were compared in each anterior and posterior tooth with the help of paired-sample t-test while Pearson's correlation(r) was used to test the correlation between the observed values. The level of statistical significance was set at P < 0.05. Results: The results were found to be highly significant both in terms of statistical (P-value) and clinical (r) significance for various sites in the anterior and posterior teeth in all instances. Conclusions: From the observations made from the present study, it could be concluded that CBCT provided highly precise assessment of bone topography equivalent to the judgment obtained during surgical exposure at the sites of interest preoperatively, which helped in assessing the exact type and depth of defect present and helped in optimizing surgical treatment planning.

Keywords: Cone-beam computed tomography, in-vivo study, periodontal disease, vertical bone defects


How to cite this article:
Chandran A, Das M, Gufran K, Khan MS, Alqahtani AS, Chikkanna M, Swarnalatha C, Babu J S, Nayyar AS. A single-center detection of adult patients with advanced periodontal disease using surgical assessment and cone-beam computed tomography. Niger J Basic Clin Sci 2022;19:101-6

How to cite this URL:
Chandran A, Das M, Gufran K, Khan MS, Alqahtani AS, Chikkanna M, Swarnalatha C, Babu J S, Nayyar AS. A single-center detection of adult patients with advanced periodontal disease using surgical assessment and cone-beam computed tomography. Niger J Basic Clin Sci [serial online] 2022 [cited 2022 Nov 29];19:101-6. Available from: https://www.njbcs.net/text.asp?2022/19/2/101/361895




  Introduction Top


Periodontal disease is characterized by the destruction of supporting tissues of teeth by the action of chemical mediators generated by the inflammatory process.[1] Surgical exposure remains the only mean to ascertain the precision of defects or, any other occult pathology in such circumstances, though, it itself has a clinically significant disadvantage of being a procedure wherein a preoperative judgment cannot be made for the type and depth of the bone defect present for formulating the treatment plan.[2] Medical imaging using X-ray-emitting modalities plays an important role in the diagnosis of periodontal disease. However, the challenge with an overlap of anatomical structures is often a limitation in the use of conventional radiography.[2],[3] This limitation can be overcome with the use of conventional computed tomography (CT) which, also, provides clear, three-dimensional information. However, the high dose from conventional CT as well as issues with the beam hardening artefacts is a challenge.[4] Although dental bitewing or interproximal radiography has been significant in the evaluation of alveolar bone architecture including alveolar bone height, important features of alveolar bone may go undetected as a result of considerable overlapping of structures or an unfavorable orientation of central beam of X-rays in the area of interest.[2],[3] Cone-beam computed tomography (CBCT) has emerged as an effective imaging modality in such situations offering high-quality images and lower radiation exposure to patients and simultaneously, being able to provide exacting information at the sites of interest preoperatively, which is actually equivalent to the information obtained after surgical exposure.[5],[6] CBCT has opened up a new vista in maxillofacial imaging with its ability to facilitate the transition of diagnostics from two-dimensional to three-dimensional imaging as well as its potential to expand the role of dental imaging from mere diagnosis to image-guided operative procedures and surgeries. Numerous studies have validated the use of CBCT in the planning of implant cases, in temporomandibular disorders (TMDs), in the diagnosis of embedded teeth, in orthodontics and dentofacial orthopedics, and in numerous other pathologies; however, few have analyzed the need for CBCT in periodontal diagnosis and treatment planning.[7],[8] Recently, a few in-vivo studies have been published concerning periodontal bone defect measurements using CBCT; however, only a few of these actually relate to the accuracy of CBCT in the assessment of horizontal bone defects in addition to vertical bone defects, which form the mainstay of these studies.[9],[10],[11] A number of studies have found CBCT to be as accurate as direct measurements made using periodontal probe as well as with better precision when compared to conventional and digital radiographic procedures.[12],[13] The main advantages of CBCT include good accessibility and easy handling in addition to a real-size data set with multi-planar cross-sectional images and three-dimensional image reconstructions based on a single scan at low radiation exposure with optimal image quality, which have actually made CBCT even more promising than CT. Also, for detection of even the smallest of the osseous defects, CBCT can display images in their totality in all three dimensions by removing interfering anatomical structures making it possible to comprehensively evaluate the area of surgical interest.[14],[15] The aim of the present study was to assess the role of CBCT in the detection of intra-bony defects in patients with advanced periodontal disease.


  Materials and Methods Top


Design and settings

The present study was designed as a prospective, observational study involving adult subjects of both genders who were aged between 35–55 years and were diagnosed with advanced periodontal disease and indicated for periodontal treatment in form of periodontal surgeries. The study duration was kept at 1 year from Summer of 2019 to Summer of 2020.

Study population

The present study included 60 patients with chronic periodontitis with 12 teeth each including 6 anterior and 6 posterior teeth per arch while specific sites in the select teeth were subjected to take measurements pre- and peri-operatively. The bone defects were measured first with the help of CBCT software installed in an individualized system devised to be used for storing and analyzing CBCT images and then, during surgical intervention using standardized UNC-15 periodontal probe and compared.

Data collection

The present study included adult subjects of both genders who were diagnosed with advanced periodontal disease and were indicated CBCT for preoperative analysis regarding the type and depth of defect present for optimizing the treatment planning wherein subjects with various systemic diseases, pregnant and lactating females, subjects with a habit of smoking or, tobacco chewing, subjects with wasting disease like attrition, abrasion, erosion, and abfraction, and subjects who had undergone restorative procedures in the site of interest were excluded.

Ethical considerations

The study was approved by the institutional research and ethics committee (SDDC/IEC/07-34-2019). Subjects enlisted gave informed signed consent. Demographic data from the patients did not include their names and addresses to maintain anonymity as much as possible. This anonymity was reinforced during data collection as well, from the monitor of the CBCT with the activation of the image anonymity feature.

Methods

For all the patients included in the present study, 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 in the sites selected for measurement of bone defects: B- Buccal; BD- Buccal/Distal; BM- Buccal/Mesial; D- Distal; DB- Distal/Buccal; DP- Distal/Palatal or Lingual in case of mandibular; M- Mesial; MB- Mesial/Buccal; MP- Mesial/Palatal or, Lingual; P- Palatal or, L-Lingual; PD-Palatal or Lingual/Distal; and PM- Palatal or Lingual/Mesial in case of maxillary and mandibular teeth, respectively.

Presurgical preparation

Each patient received initial periodontal treatment in the Department of Periodontics including full mouth scaling and root planning along with oral hygiene and plaque control instructions to eliminate active inflammation. Once the hygiene phase was completed and patients showed plaque proficiency, surgical therapy was initiated.

Radiographic assessment

CBCT images were acquired with the patient in an erect position in a single 360° rotation of the gantry around the head of the patient. The scans were carried out on Newtom-Giano equipment in the Department of Radiology at 120 KVp and 200 mA settings. The standard image acquisition time was 36 s. The scans were obtained in direct axial sections and coronal and sagittal planes were reconstructed with a contiguous slice thickness of 2 mm using a bone window. In the present study, a voxel size of 0.2 mm was used to obtain high-resolution images. All scans were evaluated by a senior radiologist. Following image acquisition, measurements of bone defects were done using NNT software version 5.4 (New Net Technologies, LLC, Atlanta, Georgia, USA) integrated with Newtom-Giano equipment [Figure 1]a,[Figure 1]b,[Figure 1]c, [Figure 2]a,[Figure 2]b,[Figure 2]c.
Figure 1: (a-c) Measurement of defect with CBCT software in Case 1

Click here to view
Figure 2: (a-c) Measurement of defect with CBCT software in Case 2

Click here to view


Surgical procedure

The patients were, then, subjected to conventional open flap debridement (OFD) procedure in the Department of Periodontics while the depth of bone defects was measured during the procedure in the sites specified wherein CBCT images were acquired using the standard UNC-15 periodontal probe. Measurement of the bone defect was done to the nearest millimeter from the coronal extension of alveolar bone crest to the deepest level of the defect [Figure 3] and [Figure 4].
Figure 3: Defect exposed after debridement in Case 1

Click here to view
Figure 4: Defect exposed after debridement in Case 2

Click here to view


Post-operative care

Antibiotic and antiinflammatory coverage was prescribed for 5 days post-operatively while all patients were instructed to rinse with 0.2% chlorhexidine gluconate mouth rinse twice daily for 4 weeks. Periodontal dressing and sutures were removed 7 days post-operatively while after 1 month, the patients were instructed to resume mechanical oral hygiene measures including careful brushing with an ultrasoft toothbrush and interdental cleaning with an interdental or proxa brush and to discontinue chlorhexidine gluconate rinse. Subgingival scaling and probing were avoided for the first 6 months to allow newly forming connective tissue to mature while patients who had received regenerative therapy were recalled after 6 months for assessing the outcome of the surgical procedure performed and complications, if any.

Statistical analysis used/Data analysis and processing

Statistical analysis was performed using SPSS version 18.0 (SPSS Inc., Chicago, IL, USA). The measurements obtained with the help of CBCT software installed in the personalized system and those obtained on surgical exploration were compared in each anterior and posterior tooth with the help of paired-sample t-test while Pearson's correlation (r) was used to test the correlation between the observed values. Unpaired-sample t-test was used to compare the data obtained in the same measurement method (CBCT or surgical). The level of statistical significance was set at P < 0.05.


  Results Top


In the present study, a mean age of 35.5 years was recorded. The palatal/lingual sites in anterior teeth, which showed a mean CBCT value of 4.0444 mm and mean surgical value of 4.1822 mm, revealed the mean difference to be statistically significant along with the distal sites, which showed a mean CBCT value of 3.3667 mm and mean surgical value of 3.5217 mm (P = 0.001) [Table 1]. However, the values in the case of posterior teeth were not found to be statistically significant [Table 1]. Furthermore, the Pearson's correlation coefficient values for various sites in the anterior and posterior teeth were found to be highly significant in all the cases (P = 0.001) [Table 2]. However, the present study revealed that within the same analytical parameters, when unpaired-sample t-test was applied, there was a significant difference between the mesial and distal sites in posterior teeth in the measurements made during the surgical intervention (P = 0.043) [Table 3].
Table 1: Comparison of measurements (in mm) from various sites in anterior and posterior teeth by paired-sample t-test

Click here to view
Table 2: Pearson's correlation (r) for various sites in anterior and posterior teeth

Click here to view
Table 3: Comparison of measurements (in mm) from various sites in the same measurement method in anterior and posterior teeth by unpaired-sample t-test

Click here to view



  Discussion Top


The aim of the present study was to assess the role of CBCT in the detection of intra-bony defects in patients with advanced periodontal disease. The findings of the study showed a mean CBCT value of 4.0444 mm and mean surgical value of 4.1822 mm in the palatal/lingual sites in anterior teeth making the difference to be statistically significant. In distal sites as well, a mean CBCT value of 3.3667 mm and a mean surgical value of 3.5217 mm was observed and the difference was found to be statistically significant (P = 0.001). The reason behind such findings was attributed to the thinner buccal and lingual cortical plates in anterior teeth than those in posterior teeth. Till date, none of the studies have indicated the least bone wall thickness that can be identified on CBCT imaging. The present study, therefore, highlights the need for further studies for assessing the minimum bone wall thickness that can be identified accurately on CBCT imaging.

Furthermore, though the values in the case of posterior teeth were more accurate than anterior teeth, they were not found to be statistically significant in the present study. This was in agreement with the findings of studies conducted by de Faria Vasconcelos et al.[3] and Feijo et al.[11] with variations found in the accuracy of CBCT in anterior and posterior teeth imaging, which are likely to be the result of differences in morphology of periodontal bone defects in specified regions. The lingual plates, in anterior region, are considerably thinner and bone tapers toward alveolar crest in the case of anterior teeth than in posterior teeth. A thinner bone plate has low image resolution, which decreases the precision of linear measurements made in the case of anterior teeth. This limitation of CT/CBCT in such cases might be due to the property denominated as partial volume averaging wherein when the limit between two tissues is in the middle of a voxel, its density is not accurately assessed by the said imaging modality, be it CT or CBCT.[14],[15] Apparently, the quality of the image slices, in such cases, is insufficient to resolve the alveolar crest reliably in said regions resulting in lesser diagnostic accuracy.

Also, although CBCT appears to be a promising option for periodontal imaging, image quality actually achievable with CBCT essentially depends on the actual dose applied during imaging. This indeed makes a difference considering the fact that despite variations in actual dose and image quality achieved, CBCT, still, proves to be a dose-sparing technique compared to CT as was concluded in a study conducted by Adejoh et al.[4] However, because there is a relative dearth of studies in this regard with not much work done in relating efficacy of CBCT as against CT, further in-vitro and in-vivo research is mandated to optimize the basic radiation dose required for obtaining optimal quality images without compromising required diagnostic detailing.[16]

Again, the spatial resolution of CBCT is dependent on voxel dimensions used during scanning while only few studies have investigated the influence of voxel dimensions on imaging outcomes in different clinical settings.[17],[18] Smaller voxel dimensions have been hypothesized to result in greater resolution of images; however, higher radiation doses are needed in such clinical settings. Wood et al.,[19] however, observed, on the contrary, that voxel-dimension had an insignificant impact on alveolar bone height measurements in CBCT imaging. In the present study, a voxel size of 0.2 mm was used to obtain high-resolution images as the present study was an in-vivo study. Several other factors cited in this regard of significance include the quantity and quality of bone being imaged, skill of the examiner, software used to view and analyze CBCT images, and presence or absence of soft tissue at, in, and around the site of interest.[20],[21],[22]

Another significant finding observed in the present study revealed that within the same analytical parameters, when unpaired-sample t-test was applied, there was a significant difference between the mesial and distal sites in posterior teeth in the measurements made during surgical intervention (P = 0.043). This difference could be explained by the fact that distal site accessibility as well as taking such measurements is difficult while performing periodontal surgeries, especially, in the case of molars. CBCT, on the contrary, provides clear imaging in the region of interest to visualize sites, which are otherwise difficult to access during surgical intervention.

The findings of the present study were, also, found to be in agreement with the results of the study conducted by Feijo et al.[11] who concluded that clinical measurements obtained using standard UNC-15 periodontal probe were found to be with an accuracy of up to 1 mm as against CBCT which allowed accuracy of up to three decimal places. In an ideal setting, a discrepancy of up to 0.5 mm between clinically and radiographically estimated bone levels is considered to be acceptable. Smaller or larger errors in locating cementoenamel junction (CEJ) and alveolar crestal levels can, on the contrary, lead to over-and under-estimation of disease progression in said situations, respectively. To conclude, CBCT can be a promising imaging modality in all such situations to help diagnose accurately the periodontal defect and its varied dimensions such as the amount of bone loss, extent, type of defect, dimensions and extent of involvement in the cases of intra-bony defects and to determine precisely prognosis of each individual tooth by allowing three-dimensional analysis of surrounding bone.


  Conclusions Top


From the observations made from the present study, it could be concluded that CBCT provided highly precise assessment of bone topography equivalent to the judgment obtained during surgical exposure at the sites of interest preoperatively, which helped in assessing the exact type and depth of defect present and helped in optimizing surgical treatment planning. This, however, mandates further clinical studies to establish selection criteria that define conditions and specific indications for the use of this imaging modality in periodontal diagnosis and treatment planning keeping radiation exposure to the minimal with optimal diagnostic accuracy. Also, bone density/volume could be detected precisely with CBCT software, which was otherwise not possible with conventional methods.

Acknowledgements

To all the patients who contributed to the study without whom this study would not have been feasible.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form, the patients have given their consent for their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
  References Top

1.
Newman M, Takei HH, Carranza FA. Clinical periodontology. In: Carranza FA, Takei HH, editors. Radiographic Aids in the Diagnosis of Periodontal Disease. Philadelphia: W.B. Saunders Company; 2002. p. 454-68.  Back to cited text no. 1
    
2.
Eskandarlo A, Bardal R, Dehghani M. Accuracy of cone beam computed tomography, intraoral radiography and periodontal probing for periodontal bone defects measurement. J Dent Med (Tehran Univ Med Sci) 2011;24:15-9.  Back to cited text no. 2
    
3.
de Faria Vasconcelos K, Evangelista KM, Rodrigues CD, Estrela C, de Sousa TO, Silva MA. Detection of periodontal bone loss using cone beam CT and intraoral radiography. Dentomaxillofac Radiol 2012;41:64-9.  Back to cited text no. 3
    
4.
Adejoh T, Ezugwu EE, Erondu FO, Okeji MC, Anumihe PO, Asogwa CO. A dual-modality quantification of scattered radiation from head to female breasts during radiological investigations in a tertiary hospital in Nigeria. Egypt J Radiol Nucl Med 2021;52:240.  Back to cited text no. 4
    
5.
Mohan R, Singh A, Gundappa M. Three-dimensional imaging in periodontal diagnosis: Utilization of cone beam computerized tomography. J Indian Soc Periodontol 2011;15:11-7.  Back to cited text no. 5
[PUBMED]  [Full text]  
6.
Banodkar AB, Gaikwad RP, Gunjikar TU, Lobo TA. Evaluation of accuracy of cone beam computed tomography for measurement of periodontal defects: A clinical study. J Indian Soc Periodontol 2015;19:285-9.  Back to cited text no. 6
[PUBMED]  [Full text]  
7.
Van Assche N, van Steenberghe D, Quirynen M, Jacobs R. Accuracy assessment of computer-assisted flapless implant placement in partial edentulism. J Clin Periodontol 2010;37:398-403.  Back to cited text no. 7
    
8.
Al-Ekrish AA, Ekram M. A comparative study of the accuracy and reliability of multi-detector computed tomography and cone beam computed tomography in the assessment of dental implant site dimensions. Dentomaxillofac Radiol 2011;40:67-75.  Back to cited text no. 8
    
9.
Walter C, Weiger R, Zitzmann NU. Accuracy of three-dimensional imaging in assessing maxillary molar furcation involvement. J Clin Periodontol 2010;37:436-41.  Back to cited text no. 9
    
10.
Leung CC, Palomo L, Griffith R, Hans MG. Accuracy and reliability of cone-beam computerized tomography for measuring alveolar bone height and detecting bony dehiscences and fenestrations. Am J Orthod Dentofacial Orthop 2010;137:S109-19.  Back to cited text no. 10
    
11.
Feijo CV, Lucena JG, Kurita LM, Pereira SL. Evaluation of cone beam computed tomography in the detection of horizontal periodontal bone defects: An in-vivo study. Int J Periodontics Restorative Dent 2012;32:e162-8.  Back to cited text no. 11
    
12.
Eshraghi T, McAllister N, McAllister B. Clinical applications of digital 2-D and 3-D radiography for the periodontist. J Evid Based Dent Pract 2012;12:36-45.  Back to cited text no. 12
    
13.
du Bois AH, Kardachi B, Bartold PM. Is there a role for the use of volumetric cone beam computerized tomography in periodontics? Aust Dent J 2012;57:103-8.  Back to cited text no. 13
    
14.
Scarfe WC, Farman AG, Levin MD, Gane D. Essentials of maxillofacial cone beam computed tomography. Alpha Omegan 2010;103:62-7.  Back to cited text no. 14
    
15.
Kamburoğlu K, Acar B, Yakar EN, Paksoy CS. Dento-maxillofacial cone beam computerized tomography. Part 1: Basic Principles (Dentomaksillofasiyal Konik Işın Demetli Bilgisayarlı Tomografi Bölüm 1: Temel Prensipler). J Clin Sci 2012;6:1125-36.  Back to cited text no. 15
    
16.
Van Dessel J, Huang Y, Depypere M, Rubira-Bullen I, Maes F, Jacobs R. A comparative evaluation of cone beam CT and micro-CT on trabecular bone structures in the human mandible. Dentomaxillofac Radiol 2013;42:20130145. doi: 10.1259/dmfr. 20130145.  Back to cited text no. 16
    
17.
de-Azevedo-Vaz SL, Vasconcelos Kde F, Neves FS, Melo SL, Campos PS, Haiter-Neto F. Detection of peri-implant fenestration and dehiscence with the use of two scan modes and the smallest voxel sizes of a cone-beam computed tomography device. Oral Surg Oral Med Oral Pathol Oral Radiol 2013;115:121-7.  Back to cited text no. 17
    
18.
Hekmatian E, Jafari-Pozve N, Khorrami L. The effect of voxel size on the measurement of mandibular thickness in cone-beam computed tomography. Dent Res J 2014;11:544-8.  Back to cited text no. 18
    
19.
Wood R, Sun Z, Chaudhry J, Ching Tee B, Kim D. Factors affecting the accuracy of buccal alveolar bone height measurements from cone-beam computed tomography images. Am J Orthod Dentofacial Orthop 2013;143:353-63.  Back to cited text no. 19
    
20.
Sun Z, Smith T, Kortam S, Kim DG, Tee BC, Fields H. Effect of bone thickness on alveolar bone-height measurements from cone-beam computerized tomography images. Am J Orthod Dentofacial Orthop 2011;139:e117-27.  Back to cited text no. 20
    
21.
Tomasi C, Bressan E, Corazza B, Mazzoleni S, Srellini E, Lith A. Reliability and reproducibility of linear mandible measurements with the use of a cone-beam computed tomography and two object inclinations. Dentomaxillofac Radiol 2011;40:244-50.  Back to cited text no. 21
    
22.
Braun X, Ritter L, Jervøe-Storm PM, Frentzen M. Diagnostic accuracy of CBCT for periodontal lesions. Clin Oral Invest 2014;18:1229-36.  Back to cited text no. 22
    


    Figures

  [Figure 1], [Figure 2], [Figure 3], [Figure 4]
 
 
    Tables

  [Table 1], [Table 2], [Table 3]



 

Top
 
 
  Search
 
Similar in PUBMED
   Search Pubmed for
   Search in Google Scholar for
 Related articles
Access Statistics
Email Alert *
Add to My List *
* Registration required (free)

 
  In this article
Abstract
Introduction
Materials and Me...
Results
Discussion
Conclusions
References
Article Figures
Article Tables

 Article Access Statistics
    Viewed273    
    Printed0    
    Emailed0    
    PDF Downloaded37    
    Comments [Add]    

Recommend this journal