|Year : 2018 | Volume
| Issue : 1 | Page : 3-10
Comparison of knowledge and perspectives toward cone-beam computed tomography among dentists in three Middle East regions: A cross-sectional study
Ebtihal H Zain-Alabdeen1, Sara M El Khateeb2
1 Department of Oral and Basic Clinical Sciences, College of Dentistry, Taibah University, Al-Madinah Al-Munawarrah, Kingdom of Saudi Arabia
2 Department of Oral Medicine, Periodontology, Diagnosis and Oral Radiology, Faculty of Dentistry, Ain Shams University, Cairo, Egypt
|Date of Web Publication||12-Mar-2018|
Ebtihal H Zain-Alabdeen
Department of Oral And Basic Clinical Sciences, College of Dentistry, Taibah University, Al-Madinah Al-Munawarrah
Kingdom of Saudi Arabia
Source of Support: None, Conflict of Interest: None
Objective: The aim of the current study was to investigate awareness, general attitudes and perspectives of a sample of dentists from Saudi Arabia, Egypt, and Jordan regarding their knowledge and future expectations of cone-beam computed tomography.
Materials and Methods: The study included a convenience sample of dentists from different specialties throughout the three regions. They were contacted through E-mail and dental social discussion groups and completed an online questionnaire. The data were collected, sorted, cross-tabulated, and analyzed in view of the objectives of the study, using descriptive analysis and Chi-square tests of significance.
Results: Age, sex, and years of experience had no effect on cone-beam computed tomography (CBCT) knowledge, whereas education level and place of work had a significant effect (P = 0.001 and P = 0.05, respectively). A change in diagnosis or treatment plan was also significantly related to the need for CBCT (P = 0.01 and P = 0.015, respectively). Requesting a dentomaxillofacial radiology (DMFR) board program was significantly related to the dentist's concern about medicolegal issues but not to the decision to refer the patient to a radiologist.
Conclusions: This study showed that having a higher education level and being in a tertiary workplace improved CBCT knowledge, and better knowledge about CBCT increased the number of patient referrals when the indications justified it. With the increasing demand for CBCT, there have been more changes in diagnoses and treatment plans, and thus, more dentists are requesting DMFR board programs in the region to avoid medicolegal issues.
Keywords: Attitude, cone-beam computed tomography, dentistry, knowledge, medicolegal, questionnaire
|How to cite this article:|
Zain-Alabdeen EH, El Khateeb SM. Comparison of knowledge and perspectives toward cone-beam computed tomography among dentists in three Middle East regions: A cross-sectional study. Saudi J Oral Sci 2018;5:3-10
|How to cite this URL:|
Zain-Alabdeen EH, El Khateeb SM. Comparison of knowledge and perspectives toward cone-beam computed tomography among dentists in three Middle East regions: A cross-sectional study. Saudi J Oral Sci [serial online] 2018 [cited 2020 Jun 2];5:3-10. Available from: http://www.saudijos.org/text.asp?2018/5/1/3/227133
| Introduction|| |
Cone-beam computed tomography (CBCT) has rapidly achieved enormous progress in maxillofacial radiology. A developing imaging modality with the advantage of rapid scan time, CBCT, is designed to produce a cone-shaped beam limited to the head and neck region while reducing radiation doses compared with computed tomography (CT). CBCT also has an interactive display that allows imaging reformation, making it beneficial for dental practices.,,,
CBCT is indicated for diagnosis, development of a treatment plan, and inferior alveolar nerve tracing in cases of the third molar extraction. It is also a useful tool in implant placement, maxillofacial surgeries, sinus pathologies, endodontics for locating additional roots, and accessory canals and for detecting vertical root fracture, orthodontic cases, orthognathic surgeries, evaluation of cysts and tumors, temporomandibular joint (TMJ) disorders, and even forensic dentistry.,
A multinational research project, SEDENTEXCT, supported by the Seventh Framework Programme of the European Atomic Energy Community (Euratom), published guidelines for the use of CBCT in 2012. SEDENTEXCT showed that in Europe, not all countries have incorporated these guidelines into their national regulations. For example, in Sweden and Norway, general radiation protection regulations and regulations regarding specialist radiographic equipment and medical CT are applied to the use of CBCT. In addition, all CBCT units have to be registered and supervised by a medical physicist responsible for performing quality assurance, including dose measurements. A medical radiologist or a dentomaxillofacial radiologist has to be responsible for the clinical use of the CBCT unit, including interpretation of the results from the examinations. The Norwegian Radiation Protection Authority published guidelines for the use of CBCT in dental practices in 2010 though these guidelines were not identical to the “Basic principles” in the EU guidelines described by the SEDENTEXCT project. Both Sweden and Norway have an acknowledged specialty in dental and maxillofacial radiology, and engaging a medical physicist is mandatory for the use of CBCT in both countries. CBCT examinations are a new challenge for dental staff.
The first CBCT scanner in Saudi Arabia was installed in 2008. Since then, CBCT has been increasingly used by dentists in the country, with the demand to have a certified dentomaxillofacial radiology (DMFR) training program increasing from year to year. In the Middle East, there is no postgraduate DMFR board training. Thus, DMFR staffs usually earn their degree from outside the region or have a master's degree in oral diagnostic sciences with a 2-year clinical certificate in DMFR but are not board certified. The rapidly growing use of CBCT in oral radiology raised our concern about the awareness of the importance of this specialty and the knowledge and attitude of all dental specialties toward CBCT usage, including the recognition of dosage limitations and the criticality of CBCT interpretations. To the best of our knowledge, no previous studies have evaluated dentists' awareness of this concern in our region. These data are important for exploring how dental clinics and educational institutions use this recent imaging technique and for assessing dentists' knowledge about CBCT indications and applications, as well as their perspectives and experience in its practice. The aim of the current study was therefore to investigate the awareness, general attitudes and perspectives of a sample of dentists from Saudi Arabia, Egypt, and Jordan regarding their knowledge and expectations of CBCT.
| Materials and Methods|| |
This observational cross-sectional study was conducted in Al Madinah Al Munawarah, Saudi Arabia, from March 2017 to June 2017. The study included a convenience sample of dentists in different specialties from private, government, and academic fields throughout the three regions. They were contacted by E-mail and through dental social discussion groups and completed an online questionnaire.
College of Dentistry Research Ethics Committee “TUCD-REC” approved this study in February 2017. Participants who only agreed to fill the anonymous self-administered questionnaire participated in the study and who refused did not participate. Confidentiality of data and anonymity of respondents guaranteed by the commitment of the principal investigator to use codes for all study participants included in this study.
The electronic anonymous questionnaire was guided by previous studies, but modified to consist of 28 questions.
It was administered to the dental specialists as a Google questionnaire and evaluated the participants' awareness regarding CBCT. The survey included demographic details of the participants: their age, sex, nationality, and specialty, as well as the duration of their experience. The remaining questions dealt with CBCT applications, frequency of use, dose, and indications.
The participating dentists were ensured that the results of the study would be confidential and used only for scientific purposes. The data were collected, sorted, and cross-tabulated. They were analyzed in view of the objectives of the study, using descriptive analysis. Data were analyzed using Stata 13.
| Results|| |
Baseline characteristics of the study participants showed that most (70%) were in the middle age group, i.e., 31–50 years; 17% were in the younger age group, i.e., 20-30 years; and 12% were >50 years. Most (76%) of the dentists interviewed were female. Most participants were from Saudi Arabia (55.6%), followed by Egypt (22.9%) and Jordan (21.5%).
Regarding the education level of the study participants, 27.8% of them had completed a bachelor's degree and 23.9% a master's degree. In addition, 29.8% held a doctoral degree, with 13.2% having clinical board certification. Only 4.9% of the individuals had postgraduate diplomas.
Of the 205 dentists in the study, 189 had heard about CBCT and 16 had never heard of it. Of the 189 who were aware of it, 160 (84.66%) either had CBCT in their clinic or had access to CBCT in the same city. The responses to the secondary questionnaire were cross-tabulated to examine the effect of these secondary variables on participants' knowledge, opinions, perspectives, and education needed for CBCT.
Effect of education level, workplace, and experience
Education level had a significant effect on CBCT knowledge [Table 1]. Of the 60 dentists who had a PhD, 35 (55.3%) had very good or good CBCT knowledge; of 47 dentists with a master's degree, 26 (55.2%) had good or sufficient CBCT knowledge; and of 44 dentists who had a bachelor's degree, 26 (59%) thought they had insufficient or no CBCT knowledge. This difference in CBCT knowledge among the education levels was significant (P = 0.001).
|Table 1: Effect of education level on cone-beam computed tomography knowledge|
Click here to view
The workplace also had a significant effect on CBCT knowledge [Table 2]. Fifty-one (70.83%) government dentists, 50 (71.42%) academic dentists, and only 22 (50%) private dentists had sufficient to very good CBCT knowledge. There was a significant difference between where the dentist worked and the level of CBCT knowledge (P = 0.05).
Years of experience had no effect on CBCT knowledge. Dentists who had sufficient to very good CBCT knowledge were recorded as having CBCT knowledge and the remainder was recorded as having no CBCT knowledge. These groups were then tested by experience: 1–5 years or >5 years. There was no significant difference between the groups [P = 0.338; [Figure 1].
|Figure 1: Percentage of cone-beam computed tomography knowledge according years of experience|
Click here to view
Referral and indications
The results showed a significant relationship between CBCT knowledge and referral of patients to CBCT (P = 0.0001). Of 125 dentists who referred patients to CBCT, 100 (80%) had CBCT knowledge; on the other hand, of 64 dentists who did not have CBCT knowledge, 29 (45.31%) referred patients to CBCT [Table 3].
|Table 3: Effect of cone-beam computed tomography knowledge on cone-beam computed tomography referral|
Click here to view
A total of 394 CBCT indications were reported by 189 dentists. The number and percentages for each type of indication for CBCT are listed in [Table 4]. [Figure 2] shows the summary of CBCT indications for the three regions of the sample.
Source of cone-beam computed tomography knowledge
The source of CBCT knowledge in the three regions showed little variation. Of the five sources of knowledge presented in the questionnaire (seminars, Internet, seniors, postgraduate studies, and others), the main source in Egypt was postgraduate studies (54.35%). In Saudi Arabia, CBCT knowledge was also through postgraduate studies but to a lesser extent (39.25%), whereas in Jordan, the main source was through seminars and workshops (44.44%). A summary of the sources of CBCT knowledge is presented in [Figure 3].
|Figure 3: Source of cone-beam computed tomography knowledge according to residency|
Click here to view
Dose awareness, referral, and need for cone-beam computed tomography
Of the 189 dentists in the sample, most (120; 69%) thought that CBCT has a higher exposure dose than a panoramic X-ray dose, whereas 69 (36.51%) thought that CBCT has an exposure dose equal to that of a panoramic X-ray. There was, however, no relation between this opinion and CBCT knowledge (P = 0.663).
Dentists who had a higher number of CBCT referrals believed that there is a need for CBCT: 117 of 129 (90%) who referred patients to CBCT indicated that there is a need for CBCT, and 35 of 50 (70%) who did not refer patients to CBCT still believed that there is a need for CBCT. The number of dentists who felt there is a need for CBCT was significantly higher (P = 0.002) than the number who felt there was no need for CBCT [Table 5].
Cone-beam computed tomography in changing the diagnosis or treatment plan
Of 189 dentists, 173 (91.53%) thought that reading CBCT images changed their diagnosis and 168 of 189 (88.88) thought that CBCT changed their treatment plan. Both groups had a significant need for CBCT (changed diagnosis: P = 0.01, changed treatment plan: P = 0.015; [Table 6]).
|Table 6: Effect of change in diagnosis and treatment plan on cone-beam computed tomography need|
Click here to view
Need for cone-beam computed tomography courses and future expectations
Among the 189 dentists, 152 recommended general CBCT courses and 33 recommended specialty CBCT courses (together 97.88%). Only 4 (2.11%) did not request any CBCT courses. Moreover, none of the dentists in the sample felt that CBCT has no future in dentistry. [Table 7] shows that 80 dentists think that CBCT will be used in all dental specialties and 81 think that it will be used in selected dental specialties, meaning that 85.18% of the dentists in this sample expected a future for CBCT.
|Table 7: Cone-beam computed tomography courses recommended and future expectations|
Click here to view
Cone-beam computed tomography as part of undergraduate and postgraduate education
Most of the respondents in Saudi Arabia (77.57%) and Egypt (76.09%) recommended teaching CBCT in the clinical years of education. In Jordan, 58.33% also recommended teaching CBCT in the clinical years, but none of the respondents in this region thought that CBCT should not be studied in the undergraduate years [Figure 4].
|Figure 4: Proposed years for teaching cone-beam computed tomography to undergraduate students according to residency|
Click here to view
Abnormal cone-beam computed tomography findings, medicolegal issues, and the need for a dentomaxillofacial radiology board in the region
About two-thirds of the dentists in the sample (121 of 189; 64.02%) indicated that they refer patients to a radiologist if there are abnormal findings on the CBCT scan, and about two-thirds of the dentists (122 of 189; 64.55%) thought that missing an abnormal finding could cause medicolegal issues, with 150 dentists (79.7%) recommending establishment of a DMFR board. This recommendation was significantly related to the dentists' viewpoints about medicolegal issues (P = 0.032) but not to dentists' opinions on referring abnormal findings to a radiologist [P = 0.741; [Table 8].
|Table 8: Recommending dentomaxillofacial radiology board in relation to referral and medicolegal issues|
Click here to view
| Discussion|| |
Studies assessing dentists' knowledge about dental radiology have focused mainly on digital systems and radiation protection. The present study assessed dentists specifically for CBCT knowledge and attitudes. With the aim of keeping up with this technology, which aids dentists and their patients, we used a questionnaire to gauge the level of knowledge regarding CBCT among a sample of dentists in three main regions in the Middle East.
Most participants were female, which reflects the demographics of the faculties as a whole. However, no differences in responses were found between female and male dentists.
In Saudi Arabia and Egypt, the source of CBCT knowledge was postgraduate studies, whereas in Jordan, it was seminars and workshops. In a study by Kamburoglu et al., seminars were the main source of CBCT knowledge for dental students; however, the CBCT course rating was poor in the study. In this study, 189 (29%) dentists attended CBCT courses. Of these 55 students, only 21.81% rated the courses as excellent, 67.27% as good, and 10.90% as fair.
The level of education was significantly associated with an increase in CBCT knowledge. This can be explained from the results of a study by Whitesides et al., who found that oral maxillofacial surgery residents were actively involved in CBCT use during their postgraduate training, which increased their education and experience in image interpretation. Our study also showed that CBCT knowledge is significantly different when stratified according to workplace, which shows different levels of interest in CBCT knowledge according to the institution where the dentist works. This result is also related to the level of education as academic professors and consultants working in government hospitals are usually highly educated and become familiar with CBCT during their postgraduate training. The study also showed that dental practitioners refer to CBCT more frequently when they have CBCT knowledge (P = 0.0001). Radiology learning is intimately linked with the study of anatomy and pathology on radiographic images, which requires advanced knowledge of anatomy, together with advanced knowledge of digital radiography and a subsequent shift from hard- to soft-copy reporting.
The indications for referral to CBCT in the three Middle East regions were similar. Having an implant was the indication with the highest frequency, followed by impaction and jaw pathology at equal frequency and then TMJ, endodontics, and other indications. Strindberg et al. also found that an implant was the indication with the highest frequency; it was markedly high in Sweden compared with Norway, where impaction was the second highest indication, followed by jaw pathology, a pain-related condition, and other indications, similar to the findings of the present study.
The source of CBCT knowledge differs from region to region. For example, across Europe, there are differences in the depth, extent, and structure of the DMFR curriculum for undergraduate dentistry and training falls under differing national governmental restrictions concerning the right to use radiation. CBCT knowledge in Europe also differs between dentists, depending on the country and date of qualification. In reality, most current dental practitioners have received insufficient or no training in interpreting CBCT images, and they have not been trained to justify or perform scans. In our study, it is clear that the source of CBCT knowledge was mainly through postgraduate training, as in Saudi Arabia and Egypt, or through workshops, as in Jordan, showing that we are on the same page as Europe regarding the need to develop a DMFR curriculum and incorporate CBCT training in undergraduate studies.
In this study, we addressed dose awareness by means of a simple question to determine dental practitioners' expectations about CBCT doses. In general, according to the American Academy of Oral and Maxillofacial Radiology, doses will differ according to the recommended examination. If an implant is going to be placed, the amount of radiation received from a CBCT of the jaws varies from approximately 18–200 μSv, depending on the size of the field of view, the resolution of the images, the size of the patient, the location of the region of interest, and the manufacturer settings. The effective dose for a panoramic radiograph, in contrast, is conservatively approximately 14 μSv. In our study, almost 70% of the participants were aware that the CBCT scan involves a higher dose than that of a panoramic radiograph.
Dentists who referred patients to CBCT and those who did not were both aware of the need for CBCT for specific indications. The dentists who indicated that the CBCT interpretation had changed either their diagnosis or their treatment plan had a significantly higher need for CBCT in their practice. This higher demand for CBCT was also seen in the literature. Garlapati et al. showed that, compared with other dental practitioners, general dentists preferred panoramic radiographs and CBCT. Panoramic radiographs were, however, advocated for fixed partial denture planning, whereas CBCT was advocated for implant planning. Moreover, there had recently been a drastic increase in the preference for CBCT over orthopantomography. In addition, Pertl et al. showed that panoramic radiographs using steel balls as a calibration reference seem to be reliable only in a standard situation, but in more difficult cases, CBCT should be used to determine available bone volume.
The three regions in this study recommended CBCT education in the clinical year for undergraduate students. At present, few dental schools teach CBCT scan acquisition and implant planning software applications to predoctoral students. Many more dental schools, however, prepare students for CBCT image interpretation., In their study, Adibi et al. stated that it is the responsibility of dental educators to integrate this technology into their curricula in a timely manner so that the next generation of oral health providers and educators will be competent in using this technology for the best interest of patients.
Dentist awareness about abnormal findings in our study was high as two-thirds of the dentists referred patients to a radiologist if there were abnormal findings on the CBCT scan, and two-thirds were also aware that missing abnormal finding can cause medicolegal issues. This awareness was revealed in their opinion that certified radiologists are needed. Since 80% of the dentists in the sample recommended the establishment of a DMFR board, this need was significantly related to their medicolegal concerns rather than the need to refer patients to a radiologist. The reason for this finding is that some dentists are knowledgeable enough to diagnose the abnormality and refer patients directly to a specialist but are not sure if they can always avoid medicolegal issues.
In this regard, some studies have reported incidental and abnormal findings within a scan regardless of the size of field of view.,,,
All of the authors of these studies recommended a complete examination of every CBCT image beyond the region of interest and advised that a radiologist needs to identify incidental findings on CBCT scans. Barghan et al. emphasized and advocated for a comprehensive review of CBCT images beyond the region of interest, especially in the base of the skull, cervical vertebrae, pharyngeal airway, and soft tissue, to avoid overlooking clinically significant lesions.
Friedland and Miles concluded from their study that the use of CBCT carries with it medicolegal risks about which the practitioner should be aware, such as licensing and malpractice responsibility concerns. They stated that a practitioner who intends to take or use CBCT scans should seek advice from the malpractice carrier before doing so. In addition, all scans should be read by someone who is competent to interpret them. Another study justified the latter recommendation, claiming that diligent dental clinicians are generally not aware of interpretation of anatomy and disease outside their immediate area of clinical interest. The failure to identify and report these findings, especially if they are pathological in nature, can lead to medical complications in the patient and can have potential medicolegal consequences for the dentist or specialist.
| Conclusions|| |
This study showed that having a higher education level and being in a tertiary workplace produced improved CBCT knowledge among dentists, and better knowledge of CBCT increased referrals to CBCT if indications justified it. With the increased demand for CBCT, there have been more frequent changes in diagnosis and treatment plans. Thus, more dentists are requesting DMFR board programs in the region to avoid medicolegal issues.
English language editing was provided by Barbara Every, ELS, of BioMedical Editor.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
| References|| |
Parashar V, Whaites E, Monsour P, Chaudhry J, Geist JR. Cone beam computed tomography in dental education: A survey of US, UK, and Australian dental schools. J Dent Educ 2012;76:1443-7.
Ramakrishnan P, Shafi FM, Subhash A, Kumara A, Chakkarayan J, Vengalath J, et al.
Asurvey on radiographic prescription practices in dental implant assessment among dentists in Kerala, India. Oral Health Dent Manag 2014;13:826-30.
Yalcinkaya SE, Berker YG, Peker S, Basturk FB. Knowledge and attitudes of Turkish endodontists towards digital radiology and cone beam computed tomography. Niger J Clin Pract 2014;17:471-8.
] [Full text]
Shetty SR, Castelino RL, Babu SG, Laxmana AR, Roopashri K. Knowledge and attitude of dentists towards cone beam computed tomography in Mangalore – A questionnaire survey. Austin J Radiol 2015;2:1016.
Balabaskaran K. Awareness and attitude among dental professional towards CBCT. IOSR J Dent Med Sci 2013;1:55-9.
Strindberg JE, Hol C, Torgersen G, Møystad A, Nilsson M, Näsström K, et al.
Comparison of Swedish and norwegian use of cone-beam computed tomography: A Questionnaire study. J Oral Maxillofac Res 2015;6:e2.
Shetty S, Castelino R, Babu S, Laxmana A, Roopashri K. Knowledge and attitude of dentists towards cone beam computed tomography in mangalore – A questionnaire survey. Austin J Radiol 2015;2:1016.
Kamburoglu K, Kursun S, Akarslan ZZ. Dental students' knowledge and attitudes towards cone beam computed tomography in Turkey. Dentomaxillofac Radiol 2011;40:439-43.
Whitesides LM, Aslam-Pervez N, Warburton G. Cone-beam computed tomography education and exposure in oral and maxillofacial surgery training programs in the United States. J Oral Maxillofac Surg 2015;73:522-8.
Vuchkova J, Maybury TS, Farah CS. Testing the educational potential of 3D visualization software in oral radiographic interpretation. J Dent Educ 2011;75:1417-25.
Brown J, Jacobs R, Levring Jäghagen E, Lindh C, Baksi G, Schulze D, et al.
Basic training requirements for the use of dental CBCT by dentists: A position paper prepared by the European Academy of Dentomaxillofacial Radiology. Dentomaxillofac Radiol 2014;43:20130291.
Pauwels R, Beinsberger J, Collaert B, Theodorakou C, Rogers J, Walker A, et al.
Effective dose range for dental cone beam computed tomography scanners. Eur J Radiol 2012;81:267-71.
Ludlow JB, Davies-Ludlow LE, White SC. Patient risk related to common dental radiographic examinations: The impact of 2007 international commission on radiological protection recommendations regarding dose calculation. J Am Dent Assoc 2008;139:1237-43.
Garlapati K, Babu DBG, Chaitanya NCSK, Guduru H, Rembers A, Soni P, et al.
Evaluation of preference and purpose of utilisation of cone beam computed tomography (CBCT) compared to orthopantomogram (OPG) by dental practitioners – A cross-sectional study. Pol J Radiol 2017;82:248-51.
Pertl L, Gashi-Cenkoglu B, Reichmann J, Jakse N, Pertl C. Preoperative assessment of the mandibular canal in implant surgery: Comparison of rotational panoramic radiography (OPG), computed tomography (CT) and cone beam computed tomography (CBCT) for preoperative assessment in implant surgery. Eur J Oral Implantol 2013;6:73-80.
Adibi S, Zhang W, Servos T, O'Neill PN. Cone beam computed tomography in dentistry: What dental educators and learners should know. J Dent Educ 2012;76:1437-42.
Lopes IA, Tucunduva RM, Handem RH, Capelozza AL. Study of the frequency and location of incidental findings of the maxillofacial region in different fields of view in CBCT scans. Dentomaxillofac Radiol 2017;46:20160215.
Barghan S, Tahmasbi Arashlow M, Nair MK. Incidental findings on cone beam computed tomography studies outside of the maxillofacial skeleton. Int J Dent 2016;2016:9196503.
Oser DG, Henson BR, Shiang EY, Finkelman MD, Amato RB. Incidental findings in small field of view cone-beam computed tomography scans. J Endod 2017;43:901-4.
Togan B, Gander T, Lanzer M, Martin R, Lübbers HT. Incidence and frequency of nondental incidental findings on cone-beam computed tomography. J Craniomaxillofac Surg 2016;44:1373-80.
Friedland B, Miles DA. Liabilities and risks of using cone beam computed tomography. Dent Clin North Am 2014;58:671-85.
Ganguly R, Ramesh A. Systematic interpretation of CBCT scans: Why do it? J Mass Dent Soc 2014;62:68-70.
[Figure 1], [Figure 2], [Figure 3], [Figure 4]
[Table 1], [Table 2], [Table 3], [Table 4], [Table 5], [Table 6], [Table 7], [Table 8]