Age changes in the permanent upper lateral incisor

Human dental age estimation by calculation of pulp-tooth volume ratios yielded on clinically acquired cone beam computed tomography images of monoradicular teeth

Secondary dentine is responsible for a decrease in the volume of the dental pulp cavity with aging. The aim of this study is to evaluate a human dental age estimation method based on the ratio between the volume of the pulp and the volume of its corresponding tooth, calculated on clinically taken cone beam computed tomography (CBCT) images from monoradicular teeth. On the 3D images of 111 clinically obtained CBCT images (Scanora(®) 3D dental cone beam unit) of 57 female and 54 male patients ranging in age between 10 and 65 years, the pulp-tooth volume ratio of 64 incisors, 32 canines, and 15 premolars was calculated with Simplant(®) Pro software. A linear regression model was fit with age as dependent variable and ratio as predictor, allowing for interactions of specific gender or tooth type. The obtained pulp-tooth volume ratios were the strongest related to age on incisors.

On the applicability of secondary dentin formation to radiological age estimation in young adults

The literature provides linear regression formulas for dental age estimation that is based on radiological two-dimensional measurements of the pulp size. The aim of the present study was to explore whether the previously presented regression formulas could lead to statistically sound results and to appropriate repeatability when applied to young individuals. Orthopantomograms (OPGs) of 44 Austrian individuals, aged between 13 and 24 years, were selected at random. In accordance with the reported method, six teeth on each OPG were chosen to carry out the measurements. Statistical analysis was performed in order to assess the difference between the estimated and the true chronological age. The regression formulas reported by Kvaal et al. (1995) led to a consistent underestimation; the regression formulas reported by Paewinsky et al. (2005) resulted in a constant overestimation of age. The statistical analysis of intraobserver and interobserver variation revealed a variation width below 2%, respectively.

The coronal pulp cavity index: a biomarker for age determination in human adults

The correlation between reduction of the coronal pulp cavity and chronological age was examined in a sample of 846 intact teeth from 433 individuals of known age and sex. Panoramic (rotational) radiography was used to measure the height (mm) of the crown (CH = coronal height) and the height (mm) of the coronal pulp cavity (CPCH = coronal pulp cavity height) of 425 premolars and 421 molars from 213 males and 220 females. The tooth-coronal index (TCI) after Ikeda et al. [1985] Jpn. J. For. Med. 39:244-250) was computed for each tooth and regressed on real age. The correlation coefficients ranged from -0.92 (molars, combined sample, right side) to -0.87 (female molars), with an S.E. of the estimate ranging from 5.88-6.66 years. Correlations were slightly higher in males than females. The equations obtained allowed estimation of age in a sample of 100 teeth from both sexes (not used for the regression) with an error of +/- 5 years in 81.4% of cases for male molars. The regression formulae for estimating age obtained from the recent sample were tested on a historical sample of 100 teeth from 100-year-old skeletons with an error of +/- 5 years in 70.3% of cases for male molars. This study illustrates the potential value of a little-known aging method which can be easily applied to estimate age in both living individuals and skeletal material of unknown age.

Effect of ageing on responses of nerve fibres to pulpal inflammation in rat molars analysed by quantitative immunocytochemistry

The response of sensory nerve fibres to inflammation in young adult rat molars has recently been shown to include increases in nerve sprouting and neuropeptide content. The objective was to evaluate neural responses to class V dental preparations in molars of old (1-2 yr) as compared with young adult rats (3-4 months). Tissues were investigated immunocytochemically 4 days post-injury for the sensory neuropeptides calcitonin gene-related peptide (CGRP) and substance P. Quantitative image analysis of the material demonstrated that more immunoreactivity was present for CGRP than for substance P in intact control teeth for each age group. Four days after injury, both immunoreactivities were increased in pulp adjacent to the injury in both young and old teeth. The increase depended on at least three factors: (1) enhanced immunoreactivity of the nerve fibres; (2) increased terminal nerve sprouts near the injury and (3) elevated peptide content of the pulp tissue. Although the incidence of CGRP- and substance P-immunoreactive nerve fibres had decreased in older teeth, the proportional increases in both neuropeptides near the injury were greater in old than in young teeth, owing to a reduction in pulpal volume during ageing. Pulpal tissue was also immunostained for the low-affinity nerve growth factor receptor (p75-NGFR) as an index of pulpal ageing; and an extensive decrease was found in the old adult as compared to young adult rats. These results indicate that old rats maintain the capacity for nerve sprouting despite the decreases in p75-NGFR labelling of pulp cells, pulp volume and nerve fibre numbers that occur as part of dental ageing.

Amount of secondary dentin as an indicator of age

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 addition, 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 defined 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.

Dental cementum apposition as an indicator of age

The purposes of the present investigation were to examine various ways of measuring cementum thickness, to study its relationship with age, and to consider what contribution this factor might offer in methods for age estimation. The amount of dental cementum apposition was studied in 1000 teeth, excluding molars, from a Caucasian population. Cementum thickness was estimated according to the scoring methods suggested by Gustafson and by Johanson. In addition, the width of the cementum was measured at the apex and also at approximately one third of the root length from the apex. Statistical analyses using the SPSS package in a Cyber computer indicated a symmetric left/right distribution of cementum thickness. The sum of the cementum thickness on vestibular and lingual surfaces, measured at one third of the root length from the apex, showed the strongest correlation with age (r = 0.40 to 0.65). A reduced rate of cementum apposition was observed in the elderly. Also, maxillary teeth had more cementum on the lingual than on the vestibular surfaces. A tendency was noted for less cementum to occur in women than in men and on teeth removed from deceased persons or extracted for pathologic reasons. Correlation coefficients indicated that, for at least some types of teeth, the cementum thickness might give a significant contribution to statistical methods of age assessment.

Anatomy of the root apex and its histologic changes with age

There were 87 vital and 24 nonvital teeth for a total of 111 specimens from 47 patients. The specimens were prepared to a thickness of 500 microns with a Buehler Isomet Bone Saw. Distances were measured and recorded with a Bioquant II Image Analysis System. The mean age of the patients was 48.9 years. The median age was 52 years. The range was 51 years, with a maximum of 77 years and a minimum of 26 years. There is a positive correlation, which could not have occurred by chance, that as age increases the deviation and the width of the foramen opening both increase. This increase appears to be a result of apical cemental thickening that occurs as the patient ages. The tissue in the apical area seems to be capable of generating additional cementum as the tooth ages. The cementodentinal junction width, or most apical extent of the dentin, remains constant.

The effect of aging on tooth morphology: a study on impacted teeth

The effect of age on dental tissues was studied on histologic sections of totally impacted teeth obtained from patients between 11 and 76 years of age. Impacted teeth were used in order to obviate the influence of the environmental effects prevalent in the oral cavity. The presence of concentric denticles and diffuse calcifications was determined, and the width of secondary dentin, predentin, and cementum was measured. The width of predentin and cementum increased linearly with age, whereas the aging process of secondary dentin formation and diffuse calcifications followed a different pattern. The incidence of concentric denticles was identical for all age groups.

Location of irregular secondary dentin formation

Study of 686 lower anterior teeth with various degrees and planes of attrition revealed positive association of functional pressures with location of irregular secondary dentin. The latter, although varied in amount, was the same in each type of tooth of the same age group, and was unrelated to the degree of attrition.

Age change in the permanent upper canine teeth

Histologic study of a graded series of sections of human upper permanent canines revealed that age rather than external irritation is primary factor in production of irregular secondary dentin. The amount of irregular secondary dentin in upper canines is noticeably less than that of upper incisors for same age group.