Amount of secondary dentin as an indicator of age
Tore Solheim Section for Forensic Odontoiogy, Department of Pathology, Dentai Faculty, University of Oslo, Osio, Norway
Solheitn T: Amoitnt of secondary detitin as an indicator of age. Scatid J Dent Res 1992; 100: 193-9. The amount of secondary dentin in a tooth has been used as one of several parameters in methods for age estimation. Dentin deposition has been measured according to various scoring systems, and the Pearson correlation coefficient with age has been found to be approximately 0.6. In the present study of 1000 teeth, molars excluded, secondary dentin was estimated according to three scoring systems. The teeth were prepared according to the half tooth technique. In additioti, the area of the coronal pulp and the widths of the root and pulp chamber were measured in a stereomicroscope at the cemento-enamel junction and at three other defmed points along the root. The Pearson correlation coefficient between age and secondary dentin varied in different types of teeth. Of the scoring systems, scores according to JOHANSON were most strongly correlated with age (r = 0.59 to 0.74). Correlation between age and the coronal pulp area varied from -0.47 to -0.72, and the range between age and ratio between pulp- and tooth width at the cemento-enamel junction was from -0.46 to -0.77. Correlations between age and ratio between sum of pulp widths and the sum of tooth widths for all four such measurements ranged from -0.58 to -0.81. Multiple regression analyses showed that by combining several types of measurements, the correlation with age was increased. A tendency was also observed towards reduced speed of secondary dentin formation in the elderly and in women.
Secondary dentin may be defmed as the dentin formed continuously throughout life after the crown is fully formed (1). This deposit was used as one of the parameters for age estimation in the method introduced by GUSTAFSON (2, 3). This scoring system is mainly based on estimates of the length of the pulp chamber, and the correlation coefficient with age was later found to be r = 0.61 (4). Increasing the number of scores from 4 to 5 only reduced the correlation to r = 0.55 (4). JOHANSON (5) further increased the number of possible scores to 7 and found a correlation in his material of r = 0.66. His scores, like those of GUSTAFSON, were related to the reduction in length of the pulp chamber, but they had more subdivisions. For mandibular first molars a correlation between age and the height ofthe pulp chamber has been found to be r = - 0 . 7 5 (6), which is somewhat stronger than that reported for all teeth in methods for age calculation (4, 5). Formation of secondary dentin starts at the side of the pulp where the antagonist meets the tooth during mastication (7-9), and seems to be mainly related to age (6). Contrary to common opinion secondary dentin formation seems only to a minor extent to be influenced by attrition (6). Coronal
Key words: age determination by teeth; age factors; dentin, secondary; sex characteristics Tore Soiheim, Box 1052 Blindern, N-0316 Osio, Norway Accepted for publication 1 August 1991
secondary dentin fonnation may be increased by external factors. Changes in osmotic pressure throughout the tooth substance in such cases have been claimed to influence the formation of secondary dentin (8). The aims of this investigation were to examine the various ways in which the amount of secondary dentin can be measured, to study its relationship with age, and to see what contribution this parameter might offer to methods for age estimation. The investigation also studied the influence that sex, the reason for extraction, and periodontai destruction might have on secondary dentin formation. Furthermore, multiple regression analysis for each type of tooth would be run with the object of obtaining formulas which could be employed for estimation of age when using the amount of sec- ondary dentin as the only parameter. Material and methods A detailed description of the material, consisting of 1000 teeth of known age, 100 of each type excluding molars, from a Caucasian population, has been given in a previous communication (10). A type of tooth is defined as comprising the two
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contralateral teeth of the same sort, e.g. maxillary second premolars. Calculation of tooth age was performed by subtracting the mean age of complete root formation (11) from the individual's age. Secondary dentin was studied and measured under a stereomicroscope in teeth which had been ground according to the half-tooth technique to the mid-pulpal area in a vestibulo-lingual plane (12). The amount of secondary dentin was assessed by using scores according to GUSTAFSON (SG) (2), DALITZ (SD) (4) and JOHANSON (SJ) (5); JOHANSON'S scores being doubled to avoid half-units.
Marks were made with a marking-pen on the cut surface at the vestibular side of the root at the cemento-enamel junction and at the midroot level. Additionally, marks were made at the halfway point between midroot and cemento-enamel junction, and likewise halfway between midroot and
the apex of the tooth (Fig. 1). At each of these marks the total widths of the tooth and the total widths of the pulp were measured in a stereomicroscope, using a measuring eyepiece. STC, STCQ, STM and STA indicated the total measurements of the root at the various levels from the cervical to the apical part of the tooth, SPC, SPCQ, SPM, SPA were the pulpal measurements at the corresponding levels. The measurement of pulp width was taken as an indication of the amount of secondary dentin. The quotient between pulp and tooth width was also calculated, as broader teeth might have wider pulps. In cases of divided roots, frequently found in maxillary first premolars, the measurements for each root were added together before registration. The area of the pulp coronal to the cementoenamel junction (CAP) was measured under the stereomicroscope, using a millimeter grid on a transparent film. Statistical analyses
CAP
STC SPC
STCQ SPCQ
STM SPM
STA SPA
Fig. 1. Drawing of tooth showing where the various measurements were made. CAP = area of crown pulp. STC = total tooth width at cemento-enamel junction. SPC = pulp width at the cemento-enamel junction. STCQ = total tooth width at coronal 5 of root. SPCQ = pulp width at coronal 5 of root. STM = total tooth width at midroot area. SPM = pulp width at midroot area. STA = total tooth width at apical 5 of root. SPA = pulp width at apical j of root.
The data were entered into files in a Sanyo MBC17plus5 microcomputer, using WordStar word processor program. Statistical analyses were performed in the microcomputer, using the SPSS/ PC + statistical package (13). A paired ?-test for left/right differences was performed on contralateral teeth from the same individual (20-^28 pairs of each tooth type). Since no differences were detected at the /'
Tore Solheim Section for Forensic Odontoiogy, Department of Pathology, Dentai Faculty, University of Oslo, Osio, Norway
Solheitn T: Amoitnt of secondary detitin as an indicator of age. Scatid J Dent Res 1992; 100: 193-9. The amount of secondary dentin in a tooth has been used as one of several parameters in methods for age estimation. Dentin deposition has been measured according to various scoring systems, and the Pearson correlation coefficient with age has been found to be approximately 0.6. In the present study of 1000 teeth, molars excluded, secondary dentin was estimated according to three scoring systems. The teeth were prepared according to the half tooth technique. In additioti, the area of the coronal pulp and the widths of the root and pulp chamber were measured in a stereomicroscope at the cemento-enamel junction and at three other defmed points along the root. The Pearson correlation coefficient between age and secondary dentin varied in different types of teeth. Of the scoring systems, scores according to JOHANSON were most strongly correlated with age (r = 0.59 to 0.74). Correlation between age and the coronal pulp area varied from -0.47 to -0.72, and the range between age and ratio between pulp- and tooth width at the cemento-enamel junction was from -0.46 to -0.77. Correlations between age and ratio between sum of pulp widths and the sum of tooth widths for all four such measurements ranged from -0.58 to -0.81. Multiple regression analyses showed that by combining several types of measurements, the correlation with age was increased. A tendency was also observed towards reduced speed of secondary dentin formation in the elderly and in women.
Secondary dentin may be defmed as the dentin formed continuously throughout life after the crown is fully formed (1). This deposit was used as one of the parameters for age estimation in the method introduced by GUSTAFSON (2, 3). This scoring system is mainly based on estimates of the length of the pulp chamber, and the correlation coefficient with age was later found to be r = 0.61 (4). Increasing the number of scores from 4 to 5 only reduced the correlation to r = 0.55 (4). JOHANSON (5) further increased the number of possible scores to 7 and found a correlation in his material of r = 0.66. His scores, like those of GUSTAFSON, were related to the reduction in length of the pulp chamber, but they had more subdivisions. For mandibular first molars a correlation between age and the height ofthe pulp chamber has been found to be r = - 0 . 7 5 (6), which is somewhat stronger than that reported for all teeth in methods for age calculation (4, 5). Formation of secondary dentin starts at the side of the pulp where the antagonist meets the tooth during mastication (7-9), and seems to be mainly related to age (6). Contrary to common opinion secondary dentin formation seems only to a minor extent to be influenced by attrition (6). Coronal
Key words: age determination by teeth; age factors; dentin, secondary; sex characteristics Tore Soiheim, Box 1052 Blindern, N-0316 Osio, Norway Accepted for publication 1 August 1991
secondary dentin fonnation may be increased by external factors. Changes in osmotic pressure throughout the tooth substance in such cases have been claimed to influence the formation of secondary dentin (8). The aims of this investigation were to examine the various ways in which the amount of secondary dentin can be measured, to study its relationship with age, and to see what contribution this parameter might offer to methods for age estimation. The investigation also studied the influence that sex, the reason for extraction, and periodontai destruction might have on secondary dentin formation. Furthermore, multiple regression analysis for each type of tooth would be run with the object of obtaining formulas which could be employed for estimation of age when using the amount of sec- ondary dentin as the only parameter. Material and methods A detailed description of the material, consisting of 1000 teeth of known age, 100 of each type excluding molars, from a Caucasian population, has been given in a previous communication (10). A type of tooth is defined as comprising the two
194
Solheim
contralateral teeth of the same sort, e.g. maxillary second premolars. Calculation of tooth age was performed by subtracting the mean age of complete root formation (11) from the individual's age. Secondary dentin was studied and measured under a stereomicroscope in teeth which had been ground according to the half-tooth technique to the mid-pulpal area in a vestibulo-lingual plane (12). The amount of secondary dentin was assessed by using scores according to GUSTAFSON (SG) (2), DALITZ (SD) (4) and JOHANSON (SJ) (5); JOHANSON'S scores being doubled to avoid half-units.
Marks were made with a marking-pen on the cut surface at the vestibular side of the root at the cemento-enamel junction and at the midroot level. Additionally, marks were made at the halfway point between midroot and cemento-enamel junction, and likewise halfway between midroot and
the apex of the tooth (Fig. 1). At each of these marks the total widths of the tooth and the total widths of the pulp were measured in a stereomicroscope, using a measuring eyepiece. STC, STCQ, STM and STA indicated the total measurements of the root at the various levels from the cervical to the apical part of the tooth, SPC, SPCQ, SPM, SPA were the pulpal measurements at the corresponding levels. The measurement of pulp width was taken as an indication of the amount of secondary dentin. The quotient between pulp and tooth width was also calculated, as broader teeth might have wider pulps. In cases of divided roots, frequently found in maxillary first premolars, the measurements for each root were added together before registration. The area of the pulp coronal to the cementoenamel junction (CAP) was measured under the stereomicroscope, using a millimeter grid on a transparent film. Statistical analyses
CAP
STC SPC
STCQ SPCQ
STM SPM
STA SPA
Fig. 1. Drawing of tooth showing where the various measurements were made. CAP = area of crown pulp. STC = total tooth width at cemento-enamel junction. SPC = pulp width at the cemento-enamel junction. STCQ = total tooth width at coronal 5 of root. SPCQ = pulp width at coronal 5 of root. STM = total tooth width at midroot area. SPM = pulp width at midroot area. STA = total tooth width at apical 5 of root. SPA = pulp width at apical j of root.
The data were entered into files in a Sanyo MBC17plus5 microcomputer, using WordStar word processor program. Statistical analyses were performed in the microcomputer, using the SPSS/ PC + statistical package (13). A paired ?-test for left/right differences was performed on contralateral teeth from the same individual (20-^28 pairs of each tooth type). Since no differences were detected at the /'
