|Year : 2015 | Volume
| Issue : 1 | Page : 19-26
Attitude toward oral biopsy among general dental practitioners: Awareness and practice
Anwar B Bataineh, Huda M Hammad, Iyas A Darweesh
Faculty of Dentistry, Jordan University of Science and Technology, Irbid, Jordan
|Date of Web Publication||20-May-2015|
Prof. Anwar B Bataineh
Faculty of Dentistry, Jordan University of Science and Technology, Irbid
Source of Support: None, Conflict of Interest: None
Aims: The aim of this study was to investigate the theoretical and practical skill levels of the general dental practitioners (GDPs) toward oral biopsy and to compare these results with other developed countries. Materials and Methods: A total of 500 Jordanian GDP from the 12 major governances of the Hashemite Kingdom of Jordan were conveniently sampled and included in this cross-sectional study. Participants were asked to complete a self-reported questionnaire that was specially designed to achieve the aims and objectives of this study. Results: Results demonstrated that a significant difference exists between the perceived theoretical knowledge related to oral biopsy and the clinical practical application of this knowledge among the participant dentists. Although 93.8% of the participants claim to have the ability to diagnose oral mucosal lesions, 91.4% recognize the diagnostic importance of oral biopsy and 67% know the indications of performing an oral biopsy, only 30.7% consider the oral biopsy as a diagnostic method to be used to reach a diagnosis of an oral mucosal lesion. Conclusions: A significant difference present between the theoretical information related to oral biopsy and the practical application of this information among the GDP.
Keywords: Oral biopsy, oral cancers, oral mucosa, tumors
|How to cite this article:|
Bataineh AB, Hammad HM, Darweesh IA. Attitude toward oral biopsy among general dental practitioners: Awareness and practice. J Orofac Sci 2015;7:19-26
|How to cite this URL:|
Bataineh AB, Hammad HM, Darweesh IA. Attitude toward oral biopsy among general dental practitioners: Awareness and practice. J Orofac Sci [serial online] 2015 [cited 2019 Nov 13];7:19-26. Available from: http://www.jofs.in/text.asp?2015/7/1/19/157368
| Introduction|| |
Awareness, clinical findings and the experience of the dentist will usually form the basis of a successful judgment and diagnosis.  In some cases, in order to reach accurate diagnosis, certain and reliable tests could be done to confirm or exclude some diseases.  The effort to put dentists in the twenty-first century on a more scientific plan urges us to be "physicians" of the oral cavity.  Inaccurate diagnosis, or failure to diagnose oral disease, may have profound implications for both the patient and the clinician.  A wide array of procedures and techniques are available to assist in the diagnosis of oral disease.  The clinical and radiographic examinations may provide sufficient information for the diagnosis of certain entities.  However, lesions of the oral cavity, and especially those affecting mucous membranes, may present bizarre clinical and histopathological patterns. This is essentially true because of the salivary environment, and the complex organization of the various oral membranes.  The correlation of the clinical findings with the histopathological observations is useful, if not fundamental, for diagnosing certain oral lesions. 
The treatment decisions based on a definitive pathologic diagnosis, the biopsy is the most dependable technique that can establish the accurate diagnosis of a clinical lesion. ,,,,
In a study  to determine the overall accuracy of clinical diagnosis made by general dental practitioners (GDPs), and compare their diagnostic ability with other dental specialties; they reviewed the biopsy reports of 976 specimens and compared the presumptive clinical diagnosis made by the practitioner with the final histopathological diagnosis on each specimen. It was found that 57% of the clinical diagnoses made by the submitting dentists were incorrect. General dentists misdiagnosed lesions 45.9%, oral and maxillofacial surgeons 42.8%, endodontists 42.2%, and periodontists 41.2% of the time. In addition, the concordance between the clinical diagnosis and the definitive histopathological diagnosis achieved by GDPs and by specialists in New Zealand from 2002 to 2006 was evaluated,  they found that the vast majority 62.9% of the referrals related to biopsies was performed in the nonattached oral mucosa.
The aim of this study was to investigate the theoretical and practical skill levels of the GDPs toward oral biopsy and to compare these results with other developed countries.
| Materials and Methods|| |
This study was a cross-sectional study, which utilizes a well-structured and modified questionnaire from other similar questionnaires that were developed in other countries ,, was designed to fulfill the aims and to suit the objectives of the study, in both Arabic and English versions, was distributed to Jordanian GDPs practicing in different sectors, private sector (PS), Royal Medical Services (RMS), Jordanian Universities (JU) and the Ministry of Health (MOH) and different municipalities in Jordan, by means of direct answers from informants, either by self-completion or via interview. Direct translation from the original English version into Arabic language was performed, and then translation back into English language was carried out to verify the translation validity. Data collection continued from April 2011 to July 2011 until the targeted sample size was obtained. The questionnaire was approved by the Institutional Research Board (IRB), Jordan University of Science and Technology.
The study questionnaire consisted of two item blocks to meet the requirements and aims of the present study. The first item block addressed professional and geographic aspects including years of professional activity, country of qualification, work setting and geographic area of work. The second explored attitudes toward oral mucosal lesions through 23 questions which cover multiple related subjects, which include: Whether or not the dentist ever diagnoses such lesions, the use of biopsies as a diagnostic method, whether the dentist personally performs such biopsies or refers the patients to other professionals, reasons for not performing biopsy, where the specimen is sent for microscopic diagnosis, whether the dentist is interested in increasing the knowledge regarding oral biopsy, and the estimation by the dentist of the general public knowledge about the oral biopsy and its importance.
Questionnaire variables were: Gender, years of professional experience, Country of qualification, ability to diagnose oral lesions, methods used to confirm the diagnosis of an oral mucosal lesion, knowledge, indications, diagnostic importance and ability to perform an oral biopsy, reasons for not performing an oral biopsy, how many times an oral biopsy was performed, referral to a specialist to perform an oral biopsy, with reasons for doing it or not, whether or not the removed oral lesion is sent for histopathological examination, estimation of the need to perform an oral biopsy to reach a diagnosis or as a follow-up procedure, attendance of courses or lectures related to oral biopsy, preferable methods to improve knowledge about oral biopsy, estimation of the general public knowledge about the oral biopsy and its diagnostic importance, estimation of the need to increase the general public awareness about the oral biopsy and its diagnostic importance.
Filter-type questions to filter out respondents lacking sufficient information, and close-ended questions that provide the respondent with several predefined options to respond were mainly used in this questionnaire.
Questionnaire reliability was measured by calculating a statistical variable known as Cronbach's alpha, which ranges between 0 and 1, and the measurement tool is considered to be reliable if the value of Cronbach's alpha is higher than 0.60.  In this study, if Cronbach's alpha was found to be 0.82, the questionnaire in this study was rated as good and is considered reliable.
The data were entered into a Microsoft Office Excel 2007 spreadsheet, version 12 (Microsoft Corporation, USA) in a personal computer. All statistical calculations and data analysis were carried out using the Statistical Package for Social Science (SPSS ® ) version 13.0 (SPSS Inc. ® , Chicago, USA). Analysis included the use of descriptive statistics (frequencies and tables) and according to the analytical data needed; multiple tests were used (Chi-square test, ANOVA, t-test and Scheffe test). Significance was assessed at a level of P = 0.05.
| Results|| |
The total number of the sample included in the study was 500 GDPs working in the different sectors. Of the total number, 70 (14.1%) had 1-5 years while 179 (35.7%) had more than 15 years of clinical experience.
To estimate the theoretical skills of the GDPs with regards to oral biopsy, it was shown that: 469 (93.8%) of the GDPs had the ability to diagnose oral soft tissue lesions, 482 (96.4%) indicated that they know what is an oral biopsy, 335 (67%) they do know the indications to perform an oral biopsy and 457 (91.4%) appreciated the diagnostic importance of oral biopsy, these findings were statistically significant results, (P < 0.05).
To evaluate the GDP's practical skill levels regarding the oral biopsy showed that: Only 99 (19.8%) indicated that they do know how to perform an oral biopsy, while 37 (7.0%) would sometimes do it. These findings were statistically significant results, (P < 0.05), in favor for the GDPs who do not have the ability to perform an oral biopsy. Of the 55 dentists who claimed that they had performed oral biopsies, 32 (58.1%) did it once, and 3 (5.4%) would do it routinely when needed as shown in [Table 1].
|Table 1: Practical skill levels regarding oral biopsy among participants|
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To find out the reasons for not being able to perform an oral biopsy, the answers were distributed as the following: 343 (87.3%) of them did not have clinical training on how to perform an oral biopsy in dental school and 4 (4.0%) they do not know interpreting the results. About 71% of the GDPs who had ever performed an oral biopsy were male, which was also found to be a statistically significant finding (P = 0.04), on the other hand, no statistically significant difference between male or female GDPs was found in relation to the appreciation of the diagnostic importance of the oral biopsy (P = 0.23) [Table 2].
|Table 2: Difference in theoretical and practical skill levels regarding oral biopsy in relation to gender|
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No statistically significant differences were found in relation to the years of clinical experience, in both theoretical and practical skill levels [Table 3].
|Table 3: Difference in theoretical and practical skill levels regarding oral biopsy in relation to years of clinical experience|
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In relation to country of graduation, no statistically significant differences related to the ability to diagnose oral soft tissue lesions, or to the appreciation of the diagnostic importance of the oral biopsy were found.
Statistically significant differences were found in relation to the knowledge of the indications to perform an oral biopsy, to the ability to perform an oral biopsy, and to the history of the performed oral biopsies. The knowledge of the indications to perform an oral biopsy 100% of all the graduates of USA/Western European, the least were Jordan graduates (59), which was a statistically significant difference (P = 0.048). In relation to the ability to perform an oral biopsy, there was, again, a statistically significant difference in favor for the USA/Western European graduates (P = 0.025). A statistically significant difference was also present in relation to the previously performed oral biopsies, with the least being performed by only (5.3%) of the Jordan universities graduates (P = 0.013) [Table 4].
|Table 4: Difference in theoretical and practical skill levels regarding oral biopsy in relation to country of graduation|
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Regarding the working sector, the ability to diagnose oral soft tissue lesions and knowing the indications of performing an oral biopsy, the appreciation of the diagnostic importance of oral biopsy, and the ability to perform an oral biopsy no statistically significant differences were found among GDPs working in the different working sectors [Table 5].
|Table 5: Difference in theoretical and practical skill levels regarding oral biopsy in relation to working sector|
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The effect of the years of experience on the theoretical and practical skill levels, the geographic allocation, the theoretical and practical skill levels did not significantly differ among the contributing GDPs [Table 6].
|Table 6: Differences in theoretical and practical skill levels regarding oral biopsy in relation to geographic area of practice|
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Out of the 343 GDPs who declared that there was no clinical training in dental school related to oral biopsy, 226 (65.9%) were graduates from JU and 1 (0.3%) from Universities in USA/Western Europe. An obvious difference was noticed that was statistically significant among these groups, (P = 0.036). Totally, 152 GDPs indicated that they know how to perform an oral biopsy in theory, but they do not have the practical skills to do it [Table 7].
|Table 7: Distribution of reasons for not being able to perform an oral biopsy in relation to the country of graduation|
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In relation to the country of graduation, no statistically significant difference was noted here, (P = 0.058). Another reason for not performing oral biopsy was that there is no perceived need to do it. This was selected by 6 GDPs; 5 (83.3%) were from a JU and 1 (16.7%) from an Eastern European University (P = 0.002) [Table 8].
|Table 8: Distribution of reasons for not being able to perform an oral biopsy in relation to the working dental sector|
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On the other hand, among those 343 GDPs, no statistically significant difference was found in relation to the working dental sector (P = 0.081), working dental sector of the GDPs (P = 0.644), and all of them practice in the private dental sector (P = 0.001). The last reason, the referral to a specialist, was chosen by 315 (80.1%) of the GDPs. No statistically significant difference was found in relation to either, the country of graduation or to the working dental sector as shown in [Table 9].
|Table 9: Frequency of reasons for not referring patients to a specialist to perform an oral biopsy (n = 179)|
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Referral patient to a specialist, out of 496 GDPs who replied, 317 (63.4%) replied by "Yes," which was a statistically significant finding in favor for those who did the referral (P = 0.002). Of the 317 GDPs who had referred the patient to a specialist, the majority 266 (83.9%) referred to an oral surgeon. Statistically, the difference was significant in favor for referral to an oral surgeon specialist (P = 0.001). GDPs were also asked if they are aware that there are oral pathologists who are specialized in examining the oral biopsy samples, 360 (73%) were aware of the presence of such specialists, while 138 (27%) did not know. Statistically, this is a significant finding in favor for those who knew about this specialty (P = 0.001).
To estimate the need to perform an oral biopsy to reach a diagnosis according to their clinical experience or as a follow-up procedure. Totally, 6 (1.2%) said no need for the oral biopsy while 266 (53.2%) agreed that it is a necessary procedure, which was a statistically significant result, (P = 0.031).
More than 80% of the GDPs had never attended any courses or lectures related to oral biopsy after graduation. Only 13 (2.6%) of them attended one in the last year, 42 (8.4%) in the last 5 years, and 36 (7.2%) more than 5 years ago. These results are clearly statistically significant in favor for not attending related courses or lectures on oral biopsy (P = 0.000). When those, whose answer was more than 5 years or never, were asked about the reasons for their replies; 415 (93.7%) indicated that there are no available courses or lectures related to the subject, 10 (2.25%) thought no need for such courses or lectures, and 18 (4.0%) had no time to attend, which was a statistically significant result in favor for lack of available courses or lectures, (P = 0.000). Upon questioning the GDPs about when they read any scientific material related to oral biopsy after their graduation, more than half 52.4% answered by "never," 124 (24.8%) by "within the last year," 68 (13.6%) by "within the last 5 years" and 44 (8.8%) by "more than 5 years ago." These are significant findings in favor for never reading any scientific material related to oral biopsy after their graduation among the GDPs, (P = 0.035). On the other hand, 461 (92.2%) they would like to increase their theoretical and practical knowledge about the oral biopsy, while 37 (7.4%) have no interest, (P = 0.001). Of those who are interested in increasing their knowledge, 148 (32.1%) prefer doing it by self-reading, 399 (86.5%) through scientific lectures, and 419 (90.9%) by scientific workshops. Totally, 358 (71.6%) of the GDPs estimated that the general public have little knowledge about the oral biopsy and its diagnostic importance, while only 6 (1.2%) of them expected this knowledge to be very good, (P = 0.027).
As for the need to increase the general public awareness about the oral biopsy and its diagnostic importance, more than half of the GDPs, 304 (60.8%), considered that there is a need (P = 0.042).
| Discussion|| |
The issue of who should perform the oral biopsy remains controversial, studies on whether GDPs should perform oral biopsies, some argue that GDPs should be competent to do the majority of oral lesions but stress that suspicious lesions should be immediately referred.  Others , encourage GDPs to biopsy suspicious lesions thus assisting in the early detection of oral cancer, surgeons discourage the GDPs to perform oral biopsy, while other surgeons desire to see the oral lesions intact and not affected by healing scars from a previous biopsy.  GDPs must, therefore, be aware not only of where, when and how to perform a biopsy, but also of when to refer the patient to a specialist. 
A total of 500 GDPs were conveniently sampled, this number was higher than that analyzed by others 227 participants in England and 170 participants in Spain. , Those studies depended on mailed questionnaires which took more time to reach the participants and more time to be filled and returned; while in our study the distribution of the questionnaire was achieved by hand delivery, through face-to-face or telephone interviews and anonymity in completing the questionnaire was granted in all cases. This method for questionnaire delivery was adopted by the researcher to encourage GDPs for direct contribution.
In this study, male GDPs comprised 57.8% of the sample, which is higher than the 55.9% in study  but <73% in other study,  while the female GDPs, it was 42.7% in this study, which is more than that in a study  but <43.5% in other study. 
In this study, 35.7% of the GDPs had more than 15 years of clinical experience, this was <66.1% in a study.  On the contrary, 64.3% of the GDPs in our study were found to have <15 years of experience, which was more than the 33.9% and 18.9%. 
The studied sample included GDPs working in private and public dental sectors. The MOH and the RMS are the two main public health sectors present in Jordan. GDPs working in the PS comprised 56.2% of the sample in this study, which is more than 8.5%  and the 19.5%  were found in other studies, but <90.9%.  The GDPs in the public dental sector in this study comprised 43.8% that was <80.5% in a study. 
In this study, 93.8% of the GDPs indicated that they have the ability to diagnose oral soft tissue lesions, which is in agreement with the results found by Jornet et al.  study 94.1%, Ergun et al.  found that almost 85% of GDPs in their study admitted to having difficulties in diagnosing oral mucosal lesions.
Jornet et al.  reported that 32.1% of the GDPs in their study considered the oral biopsy as one of the diagnostic methods to arrive at a diagnosis for oral mucosal lesions, which was slightly higher than the 30.7% found in this study. The majority of the GDPs in this study indicated that they depend on the signs and symptoms of the lesion, and on their clinical experience to reach the final diagnosis, rather than the utilization of oral biopsy as a diagnostic technique.
The majority of GDPs in this study, 78.6%, did not feel competent to perform oral biopsy. It seems that lack of biopsy-related clinical experience and the preference to refer the patients to a specialist are probably the reasons for such results. Although our findings are comparable to the 79% value reported by Greenwood et al.,  they are higher than those reported by Diamanti et al.  and Jornet et al.  of 40% and 52.8%, respectively.
On the other hand, the present results showed that upon removing an oral lesion, only 1.0% of the GDPs would send the removed lesion for histopathological examination, and 7.0% would sometimes do so. However, when taking into consideration the history of ever performed biopsy; these ratios will rise to 10% and 74% respectively, since all who answered this question had previously performed oral biopsy. These results were very significantly less than in Jornet et al.  study that found 54.3% of GDPs do send the removed oral lesions to be examined and 9.2% would sometimes do so. In this context, Kondori et al.  concluded that the high rates of clinical misdiagnosis by GDPs in their study indicate that all excised lesions should be submitted for histopathological diagnosis.
Although sending of any removed oral lesion for histopathological examination is still a debatable issue,  the American Academy of Oral and Maxillofacial Pathology recommends that "all abnormal tissue be submitted promptly for microscopic evaluation and analysis."  Even though this item, in particular, was precisely adopted from the related study of Jornet et al.,  the ambiguity of this question and the fact that it may not have been clear for some of the GDPs could also have an effect on their response. In general, only 11% of GDPs in this study have ever performed an oral biopsy. This figure is close to the 14.7% in Jornet et al.  study and the 15% in Diamanti et al.  study, but significantly less than the 21% found in Warnakulasuriya and Johnson  study.
In fact, data from this study revealed that the majority of GDPs 87% did not have any clinical training related to oral biopsy in dental school. This result was much higher than the results found in both Diamanti et al.  study 50%. This difference may be attributed to different undergraduate curricula adopted by different dental schools, and to the fact that our sample included much more different dental schools from different countries than the above two related studies.
Another factor that prevented around 39% of GDPs in this study from undertaking oral biopsy procedure was the lack of experience and practical skills. This result was comparable to what was shown as the most common response (34.9%) for not performing oral biopsies among GDPs in Jornet et al.  study.
When considering the years of experience as a variable, no statistically significant differences were found in the perceived theoretical and practical skill levels related to oral biopsy (P > 0.05). Contrary to this finding, Jornet et al.  found that the assimilation of oral biopsy as a diagnostic procedure is seen to increase with the number of years of professional experience.
When considering the referral of patients to a specialist to perform an oral biopsy, this study showed that 80.1% of GDPs do so. This finding was less than the findings in Diamanti et al.  study and Coulthard et al.,  which were 85% and 84%, respectively, it was more than the findings of Cowan et al.(1995), of 62.1%, Warnakulasuriya and Johnson  of 74%; according to this study, the majority of those specialists are oral surgeons. These similar ratios clearly show that GDPs do not prefer to get involved in this surgical technique, and consider it as an area of expertise that needs a specialist.
The results of this study suggest among the study sample, a significant difference present between the perceived theoretical knowledge related to oral biopsy and the practical application of this knowledge clinically. Future studies will focus on continuous education, and training workshops on oral biopsy, and its importance should be provided to the GDPs by the various dental organizations.
| References|| |
Kowalski LP, Franco EL, Torloni H, Fava AS, de Andrade Sobrinho J, Ramos G, et al.
Lateness of diagnosis of oral and oropharyngeal carcinoma: Factors related to the tumour, the patient and health professionals. Eur J Cancer B Oral Oncol 1994;30B:167-73.
Napier SS, Cowan CG, Gregg TA, Stevenson M, Lamey PJ, Toner PG. Potentially malignant oral lesions in Northern Ireland: Size (extent) matters. Oral Dis 2003;9:129-37.
Scott SE, Grunfeld EA, McGurk M. Patient's delay in oral cancer: A systematic review. Community Dent Oral Epidemiol 2006;34:337-43.
Kalmar JR. Advances in the detection and diagnosis of oral precancerous and cancerous lesions. Oral Maxillofac Surg Clin North Am 2006;18:465-82.
Lingen MW, Kalmar JR, Karrison T, Speight PM. Critical evaluation of diagnostic aids for the detection of oral cancer. Oral Oncol 2008;44:10-22.
Studdert DM, Mello MM, Gawande AA, Gandhi TK, Kachalia A, Yoon C, et al.
Claims, errors, and compensation payments in medical malpractice litigation. N Engl J Med 2006;354:2024-33.
Woolgar JA, Beirne JC, Vaughan ED, Lewis-Jones HG, Scott J, Brown JS. Correlation of histopathologic findings with clinical and radiologic assessments of cervical lymph-node metastases in oral cancer. Int J Oral Maxillofac Surg 1995;24:30-7.
López Jornet P, Velandrino Nicolás A, Martínez Beneyto Y, Fernández Soria M. Attitude towards oral biopsy among general dentists in Murcia. Med Oral Patol Oral Cir Bucal 2007;12:E116-21.
Downer MC, Moles DR, Palmer S, Speight PM. A systematic review of measures of effectiveness in screening for oral cancer and precancer. Oral Oncol 2006;42:551-60.
Czerninski T, Nadler C, Kaplan I, Regev E, Maly A. Comparison of Clinical and Histologic Diagnosis in Lesions of Oral Mucosa. Essay Presented at: Annual Meeting of the American Academy of Oral and Maxillofacial Pathology San Antonio, TX; 2006.
Fischer DJ, Epstein JB, Morton TH, Schwartz SM. Interobserver reliability in the histopathologic diagnosis of oral pre-malignant and malignant lesions. J Oral Pathol Med 2004;33:65-70.
American Association of Oral and Maxillofacial Surgeons. Parameters and pathways: Clinical practice guidelines for oral and maxillofacial surgery; diagnosis and management of pathologic conditions. Chicago: American Association of Oral and Maxillofacial Surgeons; 2001.
Kondori I, Mottin RW, Laskin DM. Accuracy of dentists in the clinical diagnosis of oral lesions. Quintessence Int 2011;42:575-7.
Patel KJ, De Silva HL, Tong DC, Love RM. Concordance between clinical and histopathologic diagnoses of oral mucosal lesions. J Oral Maxillofac Surg 2011;69:125-33.
Diamanti N, Duxbury AJ, Ariyaratnam S, Macfarlane TV. Attitudes to biopsy procedures in general dental practice. Br Dent J 2002;192:588-92.
Melrose RJ, Handlers JP, Kerpel S, Summerlin DJ, Tomich CJ, American Academy of Oral and Maxillofacial Pathology. The use of biopsy in dental practice. The position of the American Academy of Oral and Maxillofacial Pathology. Gen Dent 2007;55:457-61.
Williams PM, Poh CF, Hovan AJ, Ng S, Rosin MP. Evaluation of a suspicious oral mucosal lesion. J Can Dent Assoc 2008;74:275-80.
Marder MZ. The standard of care for oral diagnosis as it relates to oral cancer. Compend Contin Educ Dent 1998;19:569-72, 574, 576.
McAndrew PG. Oral cancer biopsy in general practice. Br Dent J 1998;185:428.
Coulthard P, Koron R, Kazakou I, Macfarlane TV. Patterns and appropriateness of referral from general dental practice to specialist oral and maxillofacial surgical services. Br J Oral Maxillofac Surg 2000;38:320-5.
Ergun S, Ozel S, Koray M, Kürklü E, Ak G, Tanyeri H. Dentists' knowledge and opinions about oral mucosal lesions. Int J Oral Maxillofac Surg 2009;38:1283-8.
Greenwood LF, Lewis DW, Burgess RC. How competent do our graduates feel? J Dent Educ 1998;62:307-13.
Oliver RJ, Sloan P, Pemberton MN. Oral biopsies: Methods and applications. Br Dent J 2004;196:329-33.
Warnakulasuriya KA, Johnson NW. Dentists and oral cancer prevention in the UK: Opinions, attitudes and practices to screening for mucosal lesions and to counselling patients on tobacco and alcohol use: Baseline data from 1991. Oral Dis 1999;5:10-4.
[Table 1], [Table 2], [Table 3], [Table 4], [Table 5], [Table 6], [Table 7], [Table 8], [Table 9]