*Anna Turska-Szybka1, Anna Stróżyńska2, Ada Braksator2, Joanna Łuniewska2, Maria Białczak2, Sara Shamsa1
An assessment the ability to remove carious dentin using selected diagnostic methods in final year dentistry students
Ocena umiejętności usuwania zębiny próchnicowej przez studentów ostatniego roku stomatologii przy zastosowaniu wybranych metod diagnostycznych
1Department of Paediatric Dentistry, Medical University of Warsaw
Head of Department: Professor Dorota Olczak-Kowalczyk, MD, PhD
2Students’ Scientific Association, Department of Paediatric Dentistry, Medical University of Warsaw
Head of Department: Professor Dorota Olczak-Kowalczyk, MD, PhD
Wstęp. Prawidłowa ocena i umiejętne usuwanie zębiny próchnicowej stanowią główne trudności, z jakimi spotykają się studenci stomatologii podczas opracowywania ubytków. Ocena zębiny, oczywista dla doświadczonego klinicysty, często pozostaje trudna dla studenta.
Cel pracy. Ocena umiejętności usuwania zębiny próchnicowej przez studentów ostatniego roku stomatologii przy zastosowaniu wybranych metod diagnostycznych.
Materiał i metody. Do diagnostyki użyto metod: wizualno-dotykowej, LF (DIAGNOdent), FACE (Facelight) i Caries Detector. Gdy uznano ubytek jako całkowicie opracowany, dokonywano oceny przy użyciu DIAGNOdentu oraz sondy Facelight. Oceny Caries Detectorem dokonywano jako ostatniej. Wyniki poddano analizie statystycznej z użyciem współczynnika kappa Cohena, testu chi-kwadrat i U Manna-Whitneya. Obliczono zgodność metod, ilość prób potrzebną studentom do prawidłowego opracowania ubytku oraz czułość i swoistość metod względem Facelight; próg istotności p < 0,05.
Wyniki. Średnia liczba kontroli, potrzebna studentom do właściwego opracowania ubytku, wyniosła 1,5. Po pierwszej ocenie całkowicie opracowano 50,8%. Facelight jako jedyny wykazał istotną statystycznie zgodność z trzema metodami: wizualną (p = 0,001), DIAGNOdentem (p = 0,019) i wybarwiaczem (p = 0,013). Ocena dotykowa była istotnie zgodna wyłącznie z oceną wizualną (p = 0,044).
Wnioski. Studenci nie zawsze potrafią precyzyjnie określić stopień usunięcia zębiny próchnicowej. Metodą diagnostyczną o najwyższej zgodności okazał się Facelight, który może być przydatny w dydaktyce.
Introduction. Proper evaluation and skilful removal of carious dentin are major difficulties faced by dentistry students while caries excavation. Evaluation of dentin, obvious to experienced clinician, remains difficult for students.
Aim. The purpose of this study was to assess the ability of final year dentistry students to remove carious dentine, using selected diagnostic methods.
Material and methods. The following methods were used: visual-tactile, Laser Fluorescence (DIAGNOdent), FACE (Facelight) and Caries Detector. Students assessed the cavity based on visual-tactile method. When it was considered as prepared, LF and FACE examinations were performed. Caries Detector was eventually used. Results were analysed using kappa Cohen coefficient, chi-square and the Mann-Whitney U test with P < 0.05. Agreement of methods, the number of students’ attempts to prepare the cavity, as well as sensitivity and specificity of methods were calculated in relation to FACE.
Results. The average number of evaluations needed to prepare the cavity was 1.5. After the first evaluation 50.8% of cavities were prepared. FACE demonstrated statistically significant agreement with the three methods: visual (P = 0.001), LF (P = 0.019), Caries Detector dye (P = 0.013). Tactile examination was compliant only with the visual method (P = 0.044).
Conclusions. Students are not always able to accurately determine the degree of carious dentine removal. Facelight proved to be a diagnostic method with the highest consistency and usefulness in the didactic process.
For several years, modern conservative dentistry has been based on the concept of Minimal Intervention Dentistry (MID). Proper dentin evaluation is a major difficulty faced by dentistry students during caries excavation. Both tactile and visual methods are subjective and require clinical experience (1). However, it was found that the hardness of the inner layer of demineralised dentin is lower than in normal dentin (2). This explains the reason for excessive caries removal and accidental pulp exposure (3). Therefore, a number of modern methods and materials to facilitate the decision on the completion of cavity preparation have been introduced on the market. One of the diagnostic methods, Laser Fluorescence (LF), is based on the phenomenon of fluorescence of carious dental tissue excited by a laser. This phenomenon is used in DIAGNOdent (KaVo). Different data on the cut-off point for healthy dentin in clinical practice may be found in the literature. Authors suggest that higher cut-off points are more suitable for flat and occlusal surfaces due to their increased remineralising potential compared to the bottom of the cavity (3, 4). Unlu et al. (5) accepted a healthy dentin cut-off point of 30, while Lennon (6) recommend a cut-off point of only 15. A cut-off point for healthy dentin of 25, which is an average value recommended by other researchers, was used in the conducted study (3, 5, 6). Another innovative diagnostic method is based on Fluorescence Aided Caries Excavation technique (FACE), which uses a light probe emitting violet light with a wavelength of 405 nm (e.g. Facelight, W&H). Bacteria in dentin infected by caries leave behind metabolic products (porphyrins). When an exposed cavity is illuminated with light (Facelight), porphyrins show a red fluorescence, which indicates the presence of an outer layer infected with bacteria. Bacteria with red fluorescence are predominant in carious dentin (7). Another diagnostic method uses caries detector dyes, which have been used for years as an aid in caries excavation (4-16). Caries Detector (Kuraray) used in the clinical differentiation between two dentin layers in the cavity is one of these methods.
Most of research using modern methods for the assessment of cavity are based on in vitro findings (3, 5-7, 10, 12, 15-21). Only some of the studies were conducted in vivo (8, 9, 13, 22, 23). The present study was one of the first to use four techniques for in vivo assessment of cavity-bottom dentin. Each of the presented diagnostic methods can be used in everyday clinical practice.
The aim of the study was to assess final year students’ ability to remove dentin caries using selected diagnostic methods.
Material and methods
Patients of the Department of Paediatric Dentistry (Infant Jesus Teaching Hospital in Warsaw) were included in the study. The study was approved by the Bioethics Committee of the Medical University of Warsaw (approval no. KB/235/2015). The inclusion criteria were as follows: written consent of the parent/legal guardian of the qualified child, cooperative patient, good overall health status, the presence of primary caries ICDAS-II 4-6 (24) on at least one surface of permanent or deciduous teeth, Black Classification of Carious Lesions: class I to VI, no pulp exposure or inflammation.
A total of 35 patients (12 girls and 23 boys) of the Department of Paediatric Dentistry (Infant Jesus Teaching Hospital in Warsaw) were included in the study. These were generally healthy children aged between 4 and 17 years (mean age 9.88 ± 4.47 years). From a total of 71 teeth included in the study, 6 teeth were excluded due to pulp exposure during caries excavation. The final number of qualified teeth was 65, including 30 deciduous and 35 permanent teeth. During the preparation of 3 very deep cavities, caries detector was not used or the coloured dentin was not removed due to high risk of pulp exposure.
The study was conducted between December 2014 and February 2015 by seven final year dentistry students, members of the Students’ Science Society in the Department of Paediatric Dentistry (Medical University of Warsaw), under the supervision of two dentists coordinating their work. Cavity preparation was performed in accordance with the generally accepted method. Carious cavities were opened using a diamond bur, and the softened dentin was removed using a slow-speed round bur. The colour of cavity-bottom dentin as well as the presence/absence of visible probe scratches were analysed by means of visual-tactile method. When cavity preparation was considered completed by a student, the decision was verified by the supervising person. This was followed by student’s evaluation of dentin using different diagnostic methods. Evaluation using DIAGNOdent (KaVo, Biberach, Germany) was performed in accordance with manufacturer’s instructions. After calibration of the device, three subsequent measurements were performed with reference to healthy tooth tissue. Type A and B tips were used, depending on the type of dentin, by their application to the pulp chamber surface of the cavity. Peak values, i.e. the maximum values in the range between 0 and 99, were recorded.
The next stage involved an assessment of the bottom of the cavity using Facelight (W&H, Bürmoos, Austria). By placing the probe perpendicular to the surface of the pulp chamber surface, the investigator observed the light illuminating the bottom of the cavity using special glasses (550 nm long-pass filter) supplied with the kit. If Facelight showed the presence of cavity-bottom dentin caries, the investigator performed another excavation by removing the residues of infected tissue.
The fluorescent properties of Caries Detector, invisible to the human eye, may produce incorrect results when using Facelight, which significantly limited its usefulness in the study and allowed to use the method only in the final phase of research.
The measurements were repeated in the above mentioned order. Once green fluorescence was obtained, an assessment of the bottom of the cavity was performed using Caries Detector dye (Kuraray Medical Inc., Tokyo, Japan). Using a disposable brush, the dye was applied on the bottom of cavity, which was earlier carefully dried with compressed air. Ten seconds later, the cavity was rinsed with water spray for 10 seconds and gently dried with compressed air. Dentin colour was assessed (scarlet corresponded to demineralised dentin, while non-infected tissue was coded bright-pink). Statistical analysis was performed using Statistica 10. Based on all 98 measurements (Caries Detector-65), the number of attempts needed by students for proper cavity preparation, the absolute rate of caries detection using different methods, and method agreement (using Cohen’s kappa coefficient) were calculated. The specificity and sensitivity of the methods relative to Facelight, which was selected as a gold standard, were calculated. Spearman rank correlation coefficients were used for the assessment of the relationship between the ICDAS-II code and the class according to Black’s classification and the number of attempts. The Mann-Whitney U test and chi-square test were used. The level of significance was p < 0.05.
The mean number of attempts (measurements needed by a student for complete cavity preparation) was 1.5. The results were 1.6 for permanent teeth and 1.4 for deciduous dentition. The difference between the above results, calculated based on the Mann-Whitney U test, was statistically insignificant (p > 0.05). Also, no statistically significant difference was shown between the Black’s class/ICDAS-II code and the number of attempts needed. One attempt was needed to prepare more than half of cavities (50.8%, 35 teeth), two attempts were necessary in 44.6% (27 cavities), and three attempts were required in 4.6% (3 teeth) of cavities. The agreement between investigators, which was calculated using Cohen’s kappa coefficient, ranged between 7.72 and 7.91. The absolute rate of caries detection during all measurements was 49.0% for the visual method, 7.1% for the tactile method, 27.6% for DIAGNOdent, 33.7% for Facelight and 14.1% for Caries Detector. No statistically significant differences were found between the tactile method and caries detector and DIAGNOdent or Facelight (p > 0.05). Statistically significant differences were found between other methods (p < 0.05). No statistically significant relationship was found between the characteristics of carious lesions prior to cavity preparation (Black’s class or ICDAS-II code) and the percentage of attempts during which dentin caries was identified using the assessed methods (p > 0.05). For most methods, no relationship was found between the type of treated tooth (deciduous or permanent) and the percentage of attempts with detected dentin caries (tab. 1). Only for Caries Detector, caries detection rate was statistically significantly higher in deciduous teeth compared to permanent dentition (14.3 vs. 2.4%; p = 0.04).
Tab. 1. Absolute results for caries detection in permanent and deciduous teeth
| ||Visual assessment||Tactile assessment||DIAGNOdent||Facelight||Caries Detector|
*p > 0.05
The agreement between the methods, calculated using Cohen’s kappa coefficient, was weak or very weak (tab. 2). Facelight showed the highest range of the correlation coefficient and a statistically significant agreement with the highest number of methods: visual method (k = 0.322; p = 0.001), DIAGNOdent (k = 0.235; p = 0.019) and Caries Detector (k = 0.177; p = 0.013). The tactile assessment showed statistically significant correlation only with the visual method (k = 0.107; p = 0.044).
Tab. 2. Cohen’s kappa coefficient (p-values in parentheses)
| ||Caries Detector||Visual||Tactile||DIAGNOdent|
|Visual method||0.124 (0.227)|| || || |
|Tactile method||0.104 (0.325)||0.107 (0.044)*|| || |
|DIAGNOdent||0.290 (0.019)*||0.156 (0.088)||0.071 (0.347)|| |
|Facelight||0.177 (0.013)*||0.322 (0.001)*||0.093 (0.173)||0.235 (0.019)*|
*p > 0.05
The sensitivity and specificity of the methods used were calculated relative to Facelight. The visual method achieved the highest sensitivity (72.7%), but the lowest specificity (63.1%) relative to Facelight. The tactile method achieved the highest specificity (95.4%), but very low sensitivity (12.1%). DIAGNOdent showed 42.4% sensitivity and 80.0% specificity. Only specificity was calculated for the indicator (87.3%). Sensitivity was not evaluated as the tissues were assessed using caries detector if Facelight, as a reference tool, indicated the absence of caries.
The assessment of cavity-bottom dentin is a basis for the decision on further treatment. Residual carious tissue is not without significance for the therapeutic success. Two basic methods, i.e. visual and tactile, are usually used during the training of future dentists. Often, the assessment of cavity-bottom dentin, easy for a clinically experienced assistant, poses significant difficulty for a student.
A number of authors believe that graduates of dental medicine should use, in addition to visual-tactile method, current diagnostic techniques for caries diagnostics to ensure treatment that is in line with the principles of minimally invasive dentistry in the future (8, 19, 20, 25). Therefore, it is recommended that a new education programme comprising innovative methods for caries assessment should be introduced in universities. Modern diagnostic techniques combined with traditional methods may help students diagnose caries more effectively and accurately. The study showed that students needed 1.5 attempts for a complete cavity preparation. The research included final year students, who already had some clinical experience. The low number of attempts may be associated with the student’s use of additional aids for the assessment of cavity-bottom dentin during caries excavation.
Three innovative and one traditional approach, i.e. visual-tactile method, were used for dentin assessment. The agreement between these methods was weak or very weak. Facelight achieved the highest statistically significant agreement with the other three methods, whereas the traditional tactile method showed agreement only with the visual technique. Two independent in vivo studies supported the additional use of FACE in cavity-bottom caries diagnostics and found it useful in the removal of carious dentin in accordance with the MID (22, 23). In the present study, the green fluorescence induced by Facelight indicated the completion of cavity preparation as this uncomplicated and quick diagnostic method has brought many positive results, especially in in vitro studies. According to Lennon et al. (16), FACE achieved the highest sensitivity (94%), specificity (83%) and the rate of correct results (88%) compared to DIAGNOdent, caries detector and visual-tactile method in the determination of caries removal endpoint. Another study by Lennon (6) also showed higher efficacy of Facelight compared to conventional methods in complete caries removal. Lennon et al. (7) also observed, based on histological evaluation, higher efficacy of this method for the detection of carious dentin compared to conventional method, however without statistical significance compared to caries detector. However, in another study, the authors came to the opposite conclusion. According to these authors, Facelight was more effective than caries detector; however, no statistically significant results were obtained when comparing Facelight and conventional method (18). The use of Facelight aims for a more sparing cavity preparation compared to visual-tactile method or caries detector (26).
In this study, the visual method showed the highest sensitivity (72.7%), but the lowest specificity (63.1%). This means that although students are able to identify carious dentin based on its colour, they have difficulty in its proper exclusion. Lennon et al. (16) obtained similar results in their in vitro study. The visual-tactile method showed 76% sensitivity and 65% specificity.
In the present study, DIAGNOdent showed 42.2% sensitivity and 80.0% specificity. Only specificity (87.3%) was determined for the caries detector. The sensitivity of DIAGNOdent ranged between 60 and 88%, while its specificity between 50 and 90% in in vitro studies (5, 15, 16). The values obtained in other studies assessing the specificity for the caries detector ranged between 55 and 100% (5, 15, 16). These differences between DIAGNOdent and caries detector may be associated with different reference points for sensitivity and specificity assessment. They can also indicate the imperfection of the above described methods. Experience and measurement repeatability are also emphasised as they may influence the outcomes obtained with the use of DIAGNOdent (5).
According to final year dentistry students, Facelight probe proved a very helpful and easy-to use tool, as confirmed by the study.
In many cases, particularly during deep caries excavation, when the visual-tactile method, DIAGNOdent and Facelight indicated no need for further dentin removal, caries detector produced scarlet colour at the cavity bottom, indicating probably poorly mineralised and demineralised peripulpal dentin without the presence of bacteria. Eventually, it was decided not to use caries detector or not to remove the coloured dentin in the case of very deep cavities. Other authors also decided to leave the coloured dentin on the axial and pulp chamber walls to avoid pulp exposure (1, 8). The method was considered to be less accurate compared to LF; therefore caution is recommended when using it during bottom caries removal, especially in carious lesions covering 1/3 of pulp chamber dentin (5).
Many authors agree on the need to use several methods for the assessment of carious dentin. The present study confirmed that Facelight is an appropriate reference as is shows statistically significantly higher agreement with most of the assessed diagnostic methods. Therefore, Facelight may be recommended to students as an easy method that does not require experience for the detection of carious dentin located at the bottom of the cavity. However, the study should be continued using more clinical material.
1. Van Thompson, Craig RG, Curro FA et al.: Treatment of deep carious lesions by complete excavation or partial removal: a critical review. J Am Dent Assoc 2008; 139(6): 705-712. 2. Ogawa K, Yamashita Y, Ichijo T, Fusayama T: The ultrastructure and hardness of the transparent layer of human carious dentin. J Dent Res 1983; 62: 7-10. 3. Celiberti P, Francescut P, Lussi A: Performance of four dentine excavation methods in deciduous teeth. Caries Res 2006; 40: 117-123. 4. Lennon AM, Buchalla W, Brune L et al.: The ability of selected oral microorganisms to emit red fluorescence. Caries Res 2006; 40: 2-5. 5. Unlu N, Ermis RB, Sener S et al.: An in vitro comparison of different diagnostic methods in detection of residual dentinal caries. Int J Dent 2010; 2010: 864935. 6. Lennon AM: Fluorescence-aided caries excavation (FACE) compared to conventional method. Oper Dent 2003; 28: 341-345. 7. Lennon AM, Attin T, Martens S, Buchalla W: Fluorescence-aided caries excavation (FACE), caries detector, and conventional caries excavation in primary teeth. Pediatr Dent 2009 Jul-Aug; 31(4): 316-319. 8. Rusyan E, Dubielecka M, Słotwińska SM, Jodkowska E: Ocena przydatności indykatora próchnicy w pracy klinicznej studentów III roku stomatologii. Nowa Stomatol 2005; 3: 118-120. 9. Akbari M, Ahrari F, Jafari M: A comparative evaluation of DIAGNOdent and caries detector dye in detection of residual caries in prepared cavities. J Contemp Dent Pract 2012; 13(4): 515-520. 10. Lai G, Zhu L, Xu X, Kunzelmann KH: An in vitro comparison of fluorescence-aided caries excavation and conventional excavation by microhardness testing. Clin Oral Invest 2014; 18(2): 599-605. 11. McComb D: Caries-Detector Dyes – How Accurate and Useful Are They? J Can Dent Assoc 2000; 66: 195-198. 12. Javaheri M, Maleki-Kambakhsh S, Etemad-Moghadam SH: Efficacy of Two Caries Detector Dyes in the Diagnosis of Dental Caries. J Dent (Tehran) 2010; 7(2): 71-76. 13. Hosoya Y, Taguchi T, Arita S, Tay FR: Clinical evaluation of polypropylene glycol-based caries detecting dyes for primary and permanent carious dentin. J Dent 2008; 36: 1041-1047. 14. Ganter P, Al-Ahmad A, Wrbas KT et al.: The use of computer-assisted FACE for minimal-invasive caries excavation. Clin Oral Invest 2014; 18: 745-751. 15. Yazici AR, Baseren M, Gokalp S: The in vitro performance of laser fluorescence and caries-detector dye for detecting residual carious dentin during tooth preparation. Quintessence Int J 2005; 36(6): 417-422. 16. Lennon AM, Buchalla W, Switalski L, Stookey GK: Residual caries detection using visible fluorescence. Caries Res 2002; 36: 615-619. 17. Zhang X, Tu R, Yin W et al.: Micro-computerized tomography assessment of fluorescence aided caries excavation (FACE) technology: comparison with three other caries removal techniques. Aust Dent J 2013; 58: 461-467. 18. Lennon AM, Buchalla W, Rassner B et al.: Efficiency of 4 Caries Excavation Methods Compared. Oper Dent 2006; 31(5): 551-555. 19. Adejumoke AA, Jarad FD, Komarov GN et al.: Assessing Caries Removal by Undergraduate Dental Students Using Quantitative Light-Induced Fluorescence. J Dent Educ 2008; 72(11): 1318-1323. 20. Parviainen H, Va?ha?nikkila? H, Laitala ML et al.: Evaluating performance of dental caries detection methods among third-year dental students. BMC Oral Health 2013; 13: 70. 21. Iwami Y, Shimizu A, Narimatsu M et al.: Relationship between bacterial infection and evaluation using a laser fluorescence device, DIAGNOdent. Eur J Oral Sci 2004; 112: 419-423. 22. Stoll R, Urban-Klein B, Giacomin P et al.: In vivo assessment of caries excavation with a fluorescence camera compared to direct bacteriological sampling and quantitative analysis using flow cytometry. Lasers Med Sci 2015 Feb; 30(2): 843-849. 23. Gugnani N, Pandit IK, Srivastava N et al.: Light induced fluorescence evaluation: A novel concept for caries diagnosis and excavation. J Conserv Dent 2011; 14: 418-422. 24. Gugnani N, Pandit IK, Srivastava N et al.: International Caries Detection and Assessment System (ICDAS). Int J Clin Pediat Dent 2011; 4(2): 93-100. 25. Rosa QF, Barcelos TM, Kaizer MR et al.: Do educational methods affect students’ ability to remove artificial carious dentine? A randomised controlled trial. Eur J Dent Educ 2013; 17(3): 154-158. 26. Lennon AM, Attin T, Buchalla W: Quantity of remaining bacteria and cavity size after excavation with FACE, caries detector dye and conventional excavation in vitro. Oper Dent 2007; 32: 236-241.