Journal of
Oral Rehabilitation
Journal of Oral Rehabilitation 2015 42; 600--604
Assessment of the progression of tooth wear on dental casts G. M. G. J. VERVOORN-VIS*, P. WETSELAAR*, M. KOUTRIS*, € AHTI†, J. AHLBERG‡ & F. LOBBEZOO* C . M . V I S S C H E R * , M . E V AL
*Department of Oral
Kinesiology, Academic Centre for Dentistry Amsterdam (ACTA), MOVE Research Institute Amsterdam, University of Amsterdam and VU University Amsterdam, Amsterdam, The Netherlands, †Department of Orthodontics, Institute of Dentistry, University of Helsinki, Helsinki, and ‡Department of Stomatognathic Physiology and Prosthetic Dentistry, Institute of Dentistry, University of Helsinki, Helsinki, Finland
Many methods are available for the grading of tooth wear, but their ability to assess the progression of wear over time has not been studied frequently. The aim was to assess whether the occlusal/incisal grading scale of the Tooth Wear Evaluation System (TWES) was sensitive enough for the detection of tooth wear progression from 14 to 23 years of age. A total of 120 sets of dental casts were gathered from 40 people, of whom impressions were made at 14, 18 and 23 years. The TWES was used to assess loss of clinical crown height throughout the entire dentition. There was a significant difference in the TWES scores SUMMARY
Introduction Dental professionals increasingly see patients with loss of tooth material due to erosion, attrition and/or abrasion. Amongst others, one can assess tooth wear clinically (‘chair-side’), on dental casts and on intra-oral photographs (1). To quantify the observed wear, various tools are available. Examples are the Tooth Wear Index (2), the Basic Erosive Wear Examination (3), the Tooth Wear Evaluation System (4–6), volume loss assessment (7) and planimetric methods (8, 9). To decide whether or not to restore the lost tooth material, the speed of the progression of tooth wear over time can be used as one of the parameters. To measure progression, a tool is needed that is simple to use in daily practice and sensitive enough to detect small changes. Nystr€ om et al. (10) and K€ on€ onen et al. (11) used planimetry to measure the area of worn tooth sur© 2015 John Wiley & Sons Ltd
between the three age groups on all teeth (Friedman tests; P < 0005 in all cases). Post hoc Wilcoxon tests revealed that the difference between the scores between 14 and 18 years and between 18 and 23 was significant for most teeth. It was concluded that the TWES is sensitive enough to detect changes in tooth wear over time. KEYWORDS: tooth wear, dental casts, assessment tools, reliability, progression Accepted for publication 14 February 2015
faces on photographs of casts. This method measures the occlusal/incisal surfaces in square millimetres. It is thus a continuous scale, which makes it suitable to follow the progression of wear over time. Nystr€ om et al. (10) found that tooth wear of the upper front teeth at 5 years of age was of low predictive value for tooth wear in young adulthood, whereas tooth wear at 14 years of age predicted adult wear well (11). For their research, the authors assumed that a 5-point scale like the Tooth Wear Index (2) would not be sensitive enough to detect progression over time (11). The Tooth Wear Evaluation System (TWES) (4–6) consists of several modules to guide the clinician with the diagnosis and treatment of tooth wear patients. The diagnostics modules, to quantify the amount of wear, are a screening module, a module with an occlusal/incisal grading scale, a module with a nonocclusal/non-incisal grading scale and a module to measure the clinical crown length. In this study, the doi: 10.1111/joor.12292
ASSESSMENT OF TOOTH WEAR PROGRESSION 8-point occlusal/incisal grading scale was used. This scale, which is an extended version of the 5-point grading scale developed by Lobbezoo and Naeije (12), divides the different amounts of tooth wear by loss in clinical crown height. The occlusal/incisal grading scale is a simple and reliable method to assess tooth wear on dental casts as well as chair-side (4). Expected is that this method will be suitable to follow progression, because the steps between the different scores are small, especially in the early phases of wear. Hence, using the casts of Nystr€ om et al. (10) and K€ on€ onen et al. (11), the aim of this study was to assess whether the occlusal/incisal grading scale of the TWES was sensitive enough for the detection of tooth wear progression over time (i.e. from 14 to 23 years of age) – not only in the upper front, but also in the lower front and in the posterior dentition.
3a = wear into the dentin with loss of clinical crown height between 1/3 and 1/2; 3b = wear into the dentin with loss of clinical crown height between 1/2 and 2/3; 4 = wear with loss of clinical crown height of more than 2/3. All teeth of all dental casts were scored with the occlusal/incisal grading scale of the TWES in Helsinki, Finland, by two observers (P.W. and M.K.) in 2 days. Each of them scored half of the dental casts, viz., sixty sets of casts. Of these casts, they both scored fifteen randomly selected sets twice as to establish the intraobserver reliability. These same 15 sets were also scored by the other observer as to establish the interobserver reliability. Statistical analyses
Materials and methods Sample One hundred and twenty sets of dental casts were available at the University of Helsinki, Finland. These casts were gathered from 40 people, of whom impressions were made at the ages of 14, 18 and 23 years from the upper and lower jaw. Thirty-five of the 40 participants also participated in the studies of Nystr€ om et al. (10) and K€ on€ onen et al. (11); five more participants were added to the current sample. The subjects were all young Finns, born in Helsinki between 1967 and 1970. Eighteen of them were male; 22 were female. They were all participants in a longitudinal study on dental development of Nystr€ om et al. (10) and K€ on€ onen et al. (11). Procedures By means of the 8-point occlusal/incisal grading scale of the TWES, tooth wear was scored by determining loss of clinical crown height as follows (4): 0 = no visible loss of tooth material; 1a = minimal loss of enamel; 1b = wear facets confined to the enamel parallel to the normal planes of contour; 1c = noticeable flattening of the enamel covering cusps or edges; 2 = wear into the dentin with loss of clinical crown height of less than 1/3; © 2015 John Wiley & Sons Ltd
For the intra-observer and inter-observer reliability, intraclass correlation coefficients (ICCs) were calculated. The ICCs were interpreted as follows: ICC075 excellent reliability. To determine whether the occlusal/incisal grading scale of the TWES is sensitive enough for the detection of tooth wear progression in the entire dentition, and not only in the upper anterior region, Friedman tests were performed for the following teeth: 17, 26, 15, 24, 13, 22, 11, 31, 42, 33, 44, 35, 46 and 37. No adjacent teeth and no occluding teeth were chosen as to minimise the dependency of the scores of neighbouring teeth. In case of significance, post hoc Wilcoxon tests were performed to check whether the significance was due to a progression from age 14 to 18, from age 18 to 23 or both. All statistical analyses were performed with SPSS version 21.*
Results The ICC values for the intra-observer reliability of the occlusal/incisal grading varied between 0740 (tooth 46) and 0989 (tooth 44). Most of them could be qualified as excellent. Only on tooth 46, the ICC was fair-to-good. The ICCs for the inter-observer reliability
*IBM Corp., Armonk, NY, USA.
601
602
G . M . G . J . V E R V O O R N - V I S et al. Table 1. Intraclass correlation coefficients (ICCs) for intra-observer and inter-observer reliability of tooth wear scoring, using the occlusal/incisal grading scale of the Tooth Wear Evaluation System on the indicated teeth (17, . . ., 37)
Intra Inter
17
26
15
24
13
22
11
31
42
33
44
35
46
37
0789 0675
0822 0500
0943 0296
0893 0900
0880 0632
0981 0940
0806 0784
0943 0784
0960 0889
0907 0911
0989 0627
0791 0543
0740 0239
0915 0781
varied between 0239 (tooth 46) and 0940 (tooth 22). The inter-observer reliability for the assessment on teeth 46 and 15 was qualified as poor; all others were fair-to-good or excellent. All ICCs are presented in Table 1. The tooth wear detected with the occlusal/incisal grading scale of the TWES at age 14 was mostly confined to the enamel, if there was any wear at all. At age 23, the ranges of tooth wear for the different teeth had increased and with time, more and more tooth wear into the dentin was seen. Table 2 shows the quartiles of the tooth wear scores at the ages 14, 18 and 23. There was a significant difference in the occlusal/incisal grading between the three age groups on all teeth (Friedman tests; P < 0005 in all cases). Post hoc Wilcoxon tests revealed that the difference between the scores between 14 and 18 years and between 18 and 23 was significant for most teeth (Table 2).
Discussion In this research, the 8-point occlusal/incisal grading scale of the TWES proved to be a reliable tool for the assessment of tooth wear on dental casts. Furthermore, a significant progression of tooth wear over time was measured with the occlusal/incisal grading scale of the TWES, not only for the six upper front teeth, but for the entire dentition. The intra-observer reliability of the occlusal/incisal grading scale of the TWES turned out to be excellent for virtually all teeth, while the inter-observer reliability was found to be fair-to-good to excellent for almost all teeth as well. These findings are in line with the observations of Lobbezoo and Naeije (12), who studied the reliability of a five point grading scale version of the occlusal/incisal grading scale of the TWES. In the study of Wetselaar et al. (4), also the occlusal/incisal grading scale of the TWES itself was
Table 2. 25th, 50th (=median) and 75th percentiles (25%, 50% and 75%) of tooth wear scores, using the occlusal/incisal grading scale of the Tooth Wear Evaluation System, per tooth per measurement moment (Age). Significance of Friedman tests and of post hoc Wilcoxon tests
Overall analysis (Friedman)
Age 14
18
Post hoc analysis (Wilcoxon)
23
Tooth
25%
50%
75%
25%
50%
75%
25%
50%
75%
P
P (14–18)
P (18–23)
17 26 15 24 13 22 11 31 42 33 44 35 46 37
0 0 0 0 1c 1a 1c 1b 1a 1b 0 0 0 0
0 1a 0 0 1c 1c 1c 1c 1c 1c 1b 0 1c 0
1a 1c 1a 1b 1c 1c 1c 2 2 1c 1c 1b 1c 1c
0 0 0 0 1c 1c 1c 1c 1b 1c 0 1 1c 0
0 1b 1a 1b 1c 1c 1c 2 2 1c 1b 1c 1c 1c
1b 1c 1b 1c 2 2 2 2 2 1c 1c 1c 1c 1c
1a 1a 0 1b 1c 1c 1c 2 1c 1c 1b 1a 1b 1c
1c 1c 1b 1c 2 1c 2 2 2 1c 1c 1c 1c 1c
1c 1c 1c 1c 2 2 2 2 2 2 1c 1c 2 1c
Oral Rehabilitation
Journal of Oral Rehabilitation 2015 42; 600--604
Assessment of the progression of tooth wear on dental casts G. M. G. J. VERVOORN-VIS*, P. WETSELAAR*, M. KOUTRIS*, € AHTI†, J. AHLBERG‡ & F. LOBBEZOO* C . M . V I S S C H E R * , M . E V AL
*Department of Oral
Kinesiology, Academic Centre for Dentistry Amsterdam (ACTA), MOVE Research Institute Amsterdam, University of Amsterdam and VU University Amsterdam, Amsterdam, The Netherlands, †Department of Orthodontics, Institute of Dentistry, University of Helsinki, Helsinki, and ‡Department of Stomatognathic Physiology and Prosthetic Dentistry, Institute of Dentistry, University of Helsinki, Helsinki, Finland
Many methods are available for the grading of tooth wear, but their ability to assess the progression of wear over time has not been studied frequently. The aim was to assess whether the occlusal/incisal grading scale of the Tooth Wear Evaluation System (TWES) was sensitive enough for the detection of tooth wear progression from 14 to 23 years of age. A total of 120 sets of dental casts were gathered from 40 people, of whom impressions were made at 14, 18 and 23 years. The TWES was used to assess loss of clinical crown height throughout the entire dentition. There was a significant difference in the TWES scores SUMMARY
Introduction Dental professionals increasingly see patients with loss of tooth material due to erosion, attrition and/or abrasion. Amongst others, one can assess tooth wear clinically (‘chair-side’), on dental casts and on intra-oral photographs (1). To quantify the observed wear, various tools are available. Examples are the Tooth Wear Index (2), the Basic Erosive Wear Examination (3), the Tooth Wear Evaluation System (4–6), volume loss assessment (7) and planimetric methods (8, 9). To decide whether or not to restore the lost tooth material, the speed of the progression of tooth wear over time can be used as one of the parameters. To measure progression, a tool is needed that is simple to use in daily practice and sensitive enough to detect small changes. Nystr€ om et al. (10) and K€ on€ onen et al. (11) used planimetry to measure the area of worn tooth sur© 2015 John Wiley & Sons Ltd
between the three age groups on all teeth (Friedman tests; P < 0005 in all cases). Post hoc Wilcoxon tests revealed that the difference between the scores between 14 and 18 years and between 18 and 23 was significant for most teeth. It was concluded that the TWES is sensitive enough to detect changes in tooth wear over time. KEYWORDS: tooth wear, dental casts, assessment tools, reliability, progression Accepted for publication 14 February 2015
faces on photographs of casts. This method measures the occlusal/incisal surfaces in square millimetres. It is thus a continuous scale, which makes it suitable to follow the progression of wear over time. Nystr€ om et al. (10) found that tooth wear of the upper front teeth at 5 years of age was of low predictive value for tooth wear in young adulthood, whereas tooth wear at 14 years of age predicted adult wear well (11). For their research, the authors assumed that a 5-point scale like the Tooth Wear Index (2) would not be sensitive enough to detect progression over time (11). The Tooth Wear Evaluation System (TWES) (4–6) consists of several modules to guide the clinician with the diagnosis and treatment of tooth wear patients. The diagnostics modules, to quantify the amount of wear, are a screening module, a module with an occlusal/incisal grading scale, a module with a nonocclusal/non-incisal grading scale and a module to measure the clinical crown length. In this study, the doi: 10.1111/joor.12292
ASSESSMENT OF TOOTH WEAR PROGRESSION 8-point occlusal/incisal grading scale was used. This scale, which is an extended version of the 5-point grading scale developed by Lobbezoo and Naeije (12), divides the different amounts of tooth wear by loss in clinical crown height. The occlusal/incisal grading scale is a simple and reliable method to assess tooth wear on dental casts as well as chair-side (4). Expected is that this method will be suitable to follow progression, because the steps between the different scores are small, especially in the early phases of wear. Hence, using the casts of Nystr€ om et al. (10) and K€ on€ onen et al. (11), the aim of this study was to assess whether the occlusal/incisal grading scale of the TWES was sensitive enough for the detection of tooth wear progression over time (i.e. from 14 to 23 years of age) – not only in the upper front, but also in the lower front and in the posterior dentition.
3a = wear into the dentin with loss of clinical crown height between 1/3 and 1/2; 3b = wear into the dentin with loss of clinical crown height between 1/2 and 2/3; 4 = wear with loss of clinical crown height of more than 2/3. All teeth of all dental casts were scored with the occlusal/incisal grading scale of the TWES in Helsinki, Finland, by two observers (P.W. and M.K.) in 2 days. Each of them scored half of the dental casts, viz., sixty sets of casts. Of these casts, they both scored fifteen randomly selected sets twice as to establish the intraobserver reliability. These same 15 sets were also scored by the other observer as to establish the interobserver reliability. Statistical analyses
Materials and methods Sample One hundred and twenty sets of dental casts were available at the University of Helsinki, Finland. These casts were gathered from 40 people, of whom impressions were made at the ages of 14, 18 and 23 years from the upper and lower jaw. Thirty-five of the 40 participants also participated in the studies of Nystr€ om et al. (10) and K€ on€ onen et al. (11); five more participants were added to the current sample. The subjects were all young Finns, born in Helsinki between 1967 and 1970. Eighteen of them were male; 22 were female. They were all participants in a longitudinal study on dental development of Nystr€ om et al. (10) and K€ on€ onen et al. (11). Procedures By means of the 8-point occlusal/incisal grading scale of the TWES, tooth wear was scored by determining loss of clinical crown height as follows (4): 0 = no visible loss of tooth material; 1a = minimal loss of enamel; 1b = wear facets confined to the enamel parallel to the normal planes of contour; 1c = noticeable flattening of the enamel covering cusps or edges; 2 = wear into the dentin with loss of clinical crown height of less than 1/3; © 2015 John Wiley & Sons Ltd
For the intra-observer and inter-observer reliability, intraclass correlation coefficients (ICCs) were calculated. The ICCs were interpreted as follows: ICC075 excellent reliability. To determine whether the occlusal/incisal grading scale of the TWES is sensitive enough for the detection of tooth wear progression in the entire dentition, and not only in the upper anterior region, Friedman tests were performed for the following teeth: 17, 26, 15, 24, 13, 22, 11, 31, 42, 33, 44, 35, 46 and 37. No adjacent teeth and no occluding teeth were chosen as to minimise the dependency of the scores of neighbouring teeth. In case of significance, post hoc Wilcoxon tests were performed to check whether the significance was due to a progression from age 14 to 18, from age 18 to 23 or both. All statistical analyses were performed with SPSS version 21.*
Results The ICC values for the intra-observer reliability of the occlusal/incisal grading varied between 0740 (tooth 46) and 0989 (tooth 44). Most of them could be qualified as excellent. Only on tooth 46, the ICC was fair-to-good. The ICCs for the inter-observer reliability
*IBM Corp., Armonk, NY, USA.
601
602
G . M . G . J . V E R V O O R N - V I S et al. Table 1. Intraclass correlation coefficients (ICCs) for intra-observer and inter-observer reliability of tooth wear scoring, using the occlusal/incisal grading scale of the Tooth Wear Evaluation System on the indicated teeth (17, . . ., 37)
Intra Inter
17
26
15
24
13
22
11
31
42
33
44
35
46
37
0789 0675
0822 0500
0943 0296
0893 0900
0880 0632
0981 0940
0806 0784
0943 0784
0960 0889
0907 0911
0989 0627
0791 0543
0740 0239
0915 0781
varied between 0239 (tooth 46) and 0940 (tooth 22). The inter-observer reliability for the assessment on teeth 46 and 15 was qualified as poor; all others were fair-to-good or excellent. All ICCs are presented in Table 1. The tooth wear detected with the occlusal/incisal grading scale of the TWES at age 14 was mostly confined to the enamel, if there was any wear at all. At age 23, the ranges of tooth wear for the different teeth had increased and with time, more and more tooth wear into the dentin was seen. Table 2 shows the quartiles of the tooth wear scores at the ages 14, 18 and 23. There was a significant difference in the occlusal/incisal grading between the three age groups on all teeth (Friedman tests; P < 0005 in all cases). Post hoc Wilcoxon tests revealed that the difference between the scores between 14 and 18 years and between 18 and 23 was significant for most teeth (Table 2).
Discussion In this research, the 8-point occlusal/incisal grading scale of the TWES proved to be a reliable tool for the assessment of tooth wear on dental casts. Furthermore, a significant progression of tooth wear over time was measured with the occlusal/incisal grading scale of the TWES, not only for the six upper front teeth, but for the entire dentition. The intra-observer reliability of the occlusal/incisal grading scale of the TWES turned out to be excellent for virtually all teeth, while the inter-observer reliability was found to be fair-to-good to excellent for almost all teeth as well. These findings are in line with the observations of Lobbezoo and Naeije (12), who studied the reliability of a five point grading scale version of the occlusal/incisal grading scale of the TWES. In the study of Wetselaar et al. (4), also the occlusal/incisal grading scale of the TWES itself was
Table 2. 25th, 50th (=median) and 75th percentiles (25%, 50% and 75%) of tooth wear scores, using the occlusal/incisal grading scale of the Tooth Wear Evaluation System, per tooth per measurement moment (Age). Significance of Friedman tests and of post hoc Wilcoxon tests
Overall analysis (Friedman)
Age 14
18
Post hoc analysis (Wilcoxon)
23
Tooth
25%
50%
75%
25%
50%
75%
25%
50%
75%
P
P (14–18)
P (18–23)
17 26 15 24 13 22 11 31 42 33 44 35 46 37
0 0 0 0 1c 1a 1c 1b 1a 1b 0 0 0 0
0 1a 0 0 1c 1c 1c 1c 1c 1c 1b 0 1c 0
1a 1c 1a 1b 1c 1c 1c 2 2 1c 1c 1b 1c 1c
0 0 0 0 1c 1c 1c 1c 1b 1c 0 1 1c 0
0 1b 1a 1b 1c 1c 1c 2 2 1c 1b 1c 1c 1c
1b 1c 1b 1c 2 2 2 2 2 1c 1c 1c 1c 1c
1a 1a 0 1b 1c 1c 1c 2 1c 1c 1b 1a 1b 1c
1c 1c 1b 1c 2 1c 2 2 2 1c 1c 1c 1c 1c
1c 1c 1c 1c 2 2 2 2 2 2 1c 1c 2 1c
