Dentin Apposition Research Articles

Exploring optimal methods for age-at-death estimation using pulp/tooth area ratios: a South African study.

Age-at-death estimation is pivotal in the identification of unknown human decedents in forensic medicine. The pulp/tooth area ratio (PAR) method, assessing pulp cavity size as a marker of secondary dentine apposition, is widely utilised for adult age estimation. Despite extensive evaluation of this technique, the influence of image type and enamel area inclusion on method accuracy is insufficiently explored. The present study evaluated the PAR method's applicability using maxillary canines from a South African cadaveric sample, examining reliability, sex bias, and accuracy across different image types and enamel area considerations. An observational, cross-sectional study design was followed. Fifty-two adult maxillary canines were radiographed, sectioned, and analysed using stereomicroscopy. Labiolingual and mesiodistal periapical radiographs, alongside labiolingual stereomicroscopic tooth section images, were analysed using ImageJ to calculate PARs. Age estimation linear regression models were developed for each image type, with and without enamel area inclusion. Models were compared for performance and accuracy using best-subsets regression and cross-validation analyses. Results indicated that the PAR method is a reliable, sex-independent technique, providing relatively accurate age-at-death estimates for South African adults. Image type significantly influenced accuracy, with tooth section images exhibiting the best/lowest error values, followed by labiolingual and mesiodistal radiographs, respectively. Exclusion of enamel area consistently enhanced model performance across all image types. This study contributes valuable data to the underexplored field of dental age estimation techniques for South African adults, highlighting optimal approaches when applying the PAR method to maxillary canines. Additionally, it introduces a refined stereomicroscopic technique, augmenting and enhancing existing practices.

Understanding dental pulp inflammation: from signaling to structure.

The pulp is a unique tissue within each tooth that is susceptible to painful inflammation, known as pulpitis, triggered by microbial invasion from carious lesions or trauma that affect many individuals. The host response involves complex immunological processes for pathogen defense and dentin apposition at the site of infection. The interplay of signaling between the immune and non-immune cells via cytokines, chemokines, neuropeptides, proteases, and reactive nitrogen and oxygen species leads to tissue reactions and structural changes in the pulp that escalate beyond a certain threshold to irreversible tissue damage. If left untreated, the inflammation, which is initially localized, can progress to pulpal necrosis, requiring root canal treatment and adversely affecting the prognosis of the tooth. To preserve pulp vitality and dental health, a deeper understanding of the molecular and cellular mechanisms of pulpitis is imperative. In particular, elucidating the links between signaling pathways, clinical symptoms, and spatiotemporal spread is essential to develop novel therapeutic strategies and push the boundaries of vital pulp therapy.

A labeling study of dentin formation rates during crown and root growth of porcine mandibular first molars.

We used fluorochrome labeling to study spatiotemporal variation of dentin apposition (DAR) and extension (DER) rates during crown and root formation of mandibular first molars from wild boar and domestic pigs. DAR was reconstructed along the course of dentinal tubules in four zones of the crown and in the upper root area. In all five zones, mean DAR increased during the first 30% to 40% of apposition, reaching highest values (22-23 μm/day) in the upper-lateral crown zone. Lowest values were recorded near the dentin-pulp interface (DPI). Typically, DARs in contemporaneously formed dentin areas were higher in more cuspally compared to more cervically/apically located zones. DER was high (>200 μm/day) in early postnatal crown dentin and then decreased markedly in cervical direction, with lowest values in the cervical crown zone. After this nadir, DER sharply increased in the upper 30% to 40% of the root extension, reaching values equaling (wild boar) or even surpassing (domestic pigs) those recorded in the upper lateral crown. After this peak, DER again decreased. While DAR did not differ markedly between wild boar and domestic pigs, the DER showed marked differences, both regarding maximum values (208.1 μm/day in wild boar, 272.2 μm/day in domestic pigs) and the timing of the root growth spurt, which occurred earlier in the domestic pigs. We consider the more rapid recruitment of secretory odontoblasts in domestic pigs (reflected by higher DER) a side effect of selection for rapid body growth during pig domestication.

Guided Endodontics: Three-dimensional Planning and Template-aided Preparation of Endodontic Access Cavities.

Pulp canal obliterations (PCO) are often a consequence of dental trauma, such as luxation injuries. Even though dentin apposition is a sign of vital pulp, pulpitis or apical periodontitis may develop in the long term. Root canal treatment of teeth with severe PCO and pulpal or periapical pathosis is challenging for general practitioners and even for well-equipped endodontic specialists. To ensure detection of the calcified root canal and avoid excessive loss of tooth structure or root perforation, static navigation using templates ("Guided Endodontics") was introduced a few years ago. The general workflow includes three-dimensional imaging using cone-beam computed tomography (CBCT), a digital surface scan, and superimposition of both in a planning software. This is followed by virtual planning of the access cavity and the design of a template that will guide the drill to the desired target point. To do this, a true-to-scale virtual image of the drill must be placed in a way that the tip of the drill reaches the orifice of the calcified root canal. Once the template has been fabricated using computer-aided design and computer-aided manufacturing (CAD/CAM) or a 3D printer, guided preparation of the access cavity can be performed clinically. For research purposes, a postoperative CBCT image can be used to quantify the accuracy of the access cavity performed. This work aims to present the technique of static guided endodontics from imaging to clinical implementation.

Evolution of amniote dentine apposition rates.

In amniotes, daily rates of dentine formation in non-ever-growing teeth range from less than 1 to over 25 μm per day. The latter value has been suggested to represent the upper limit of odontoblast activity in non-ever-growing teeth, a hypothesis supported by the lack of scaling between dentine apposition rates and body mass in Dinosauria. To determine the correlates and potential controls of dentine apposition rate, we assembled a dataset of apposition rates, metabolic rates and body masses for ca 80 amniote taxa of diverse ecologies and diets. We used phylogenetic regression to test for scaling relationships and reconstruct ancestral states of daily dentine apposition across Amniota. We find no relationship between body mass and daily dentine apposition rate (DDAR) for non-ever-growing teeth in Amniota as a whole or within major clades. Metabolic rate, the number of tooth generations, diet and habitat also do not predict or correspond with DDARs. Similar DDARs are found in large terrestrial mammals, dinosaurs and marine reptiles, whereas primates, cetaceans and some smaller marine reptiles independently evolved exceptionally slow rates. Life-history factors may explain the evolution of dentine apposition rates, which evolved rapidly at the origin of major clades.

Określenie wieku osobniczego na podstawie zębów

The set of dental traits traditionally used for identification purposes due to their high correlation with age include the attrition of the crown, periodontic changes, apposition of the secondary dentin and root cement, resorption and translucency of the root. The work puts forward a proposal to add a new trait, i.e. width of the root canal. The new trait is particularly useful for the examination of the fossil material.

Present status and future directions - Guided endodontics.

Luxation injuries and other stimuli may lead to a pulp canal obliteration (PCO). Even though the apposition of tertiary dentine is a sign of a vital pulp, in some cases root canal treatment is indicated in the long term due to apical periodontitis or pulpitis. Depending on the extent of PCO, root canal treatment may be challenging even for experienced and well-equipped endodontic specialists. The 'guided endodontics' (GE) technique was introduced 6years ago as an alternative to conventional access cavity preparation for teeth with PCO and apical pathosis or irreversible pulpitis. Using three-dimensional radiological imaging such as cone-beam computed tomography and a digital surface scan, an optimal access to the orifice of the calcified root canal can be planned virtually with appropriate software. GE is implemented either with the help of templates analogous to guided implantology (= static navigation) or by means of dynamic navigation based on a camera-marker system. GE has emerged as a field of research in the last 6years with very promising laboratory-based results regarding the accuracy of guided endodontic access cavities for both static and dynamic navigation. Clinical implementation seems to provide favourable results, but the evidence is mainly based on numerous case reports and a few case series. This narrative review aims to provide an update on the present status of GE and to identify relevant research areas that could contribute to further improvements of this technique.

Three-Dimensional Radiological Methods for Age Estimation in Adults by Using the Pulp/Tooth Relation: an Integrative Review

Assessment of secondary dentin apposition is an observable phenomenon widely used to estimate age. An integrative review was performed by searching the keywords "computed tomography AND age estimation AND pulp tooth volume ratio" and "microfocus x-ray AND age estimation AND pulp tooth volume ratio" in the electronic platforms Embase, PubMed, Scopus and Web of Science, in July 2020. Studies included: complete articles with age estimation from human teeth by use of computed tomography or micro-computed tomography, written in English, without time restriction. Excluded studies: not written in English or not in form of an article, clinical cases, literature reviews, if did not realize age estimations or if age estimation is done in animals teeth. The search resulted in 32 different articles. With application of the above criteria only 26 were reviewed. Data collected included: reference, year, country, tooth type, number of subjects, number of teeth, age group, image type, measuring instrument/software, type of analysis, coefficient of determination, correlation coefficient with age and accuracy. These data provided a quick global comparison of various methodologies that use the pulp/tooth relation, being practical for researchers and forensic team to which method they can use accordingly to a specific case and its expected accuracy.

The Effect of Missense Mutation of FAM20A on Dental Development and Mineralization

FAM20A is a Protein Coding gene. It acts as an allosteric activator of the Golgi serine/threonine protein kinase FAM20C and is involved in biomineralization of teeth. A novel homozygous deletion mutation in exon 11 of FAM20A has been described in five members from a large consanguineous Bedouin family, all five with hypoplastic-hypocalcified AI and unerupted and crown resorbed permanent molars, a very rare phenotype. Deciduous mandibular canines and first molar, and maxillary first and second molars of an affected girl were compared to normal pair-matched teeth. Slices of the teeth were examined using SEM, and the ion content of enamel and dentine was determined using Energy Dispersive X-ray Spectrometer (EDS). The deciduous teeth showed missing enamel and the dentin was hypercalcified with very few open tubuli. Calcium and phosphorous percentages were reduced by 45 % in the enamel, and extensive apposition of secondary dentin and calcification of the pulps was observed. The permanent dentition showed impacted molars, premolars and canines with hypoplastic enamel and reduced dimensions of the erupted teeth. The mutation of FAM20A caused a peculiar type of AI with very thin amorphic enamel, infraoccluded deciduous teeth and impacted permanent canines, premolars and molars.

A full Bayesian calibration model for assessing age in adults by means of pulp/tooth area ratio in periapical radiography.

The Bayesian approach is being a fundamental tool in forensic and legal field where inferences and decisions are made. In this study, a full Bayesian calibration model was developed to make probabilistic inferences about age estimation in a reference sample of 891 periapical X-rays of upper and lower canines. These teeth belonged to both deceased and living adult subjects, aged between 20 and 86years, coming from five different countries (Turkey, Italy, Portugal, Japan and Mexico). For this purpose, the narrowing of pulp chamber due to the apposition of secondary dentine was analysed by means of the pulp/tooth area ratio. To determine the agreement of the method, intra- and inter-observer differences for measuring process were calculated by means of the intraclass correlation coefficient (ICC) analysis. Observer error tests showed excellent agreement between observers and between repeated assessments. According to the results of the ANCOVA, neither nationality nor sex was associated to the secondary dentine apposition while it is associated with individual's age. The results of the present study indicated that the concept of probability is intrinsically linked to the assessment of age in a forensic context, and the Bayesian approach could be considered a robust tool to overtake the bias generated by traditional regression models, thus helping the decision-making process in a legal framework.

Age Estimation in Iranian Population Using Tooth/Pulp Ratio in Mandibular Premolars by Panoramic Radiography

Background: Age estimation is a fundamental part of forensic science. Considering the fact that pulp size decreases throughout the life because of secondary dentine apposition, many researchers have used it as a method for age estimation with great results. This study aimed to determine the applicability of tooth to pulp ratio in mandibular second premolars in an Iranian population using panoramic radiographs. Methods: The sample consisted of 153 digital panoramic images of male and female Iranians aged 13-70 years, and the tooth to pulp ratio of both left and right mandibular second premolars was obtained using AutoCAD software. Analysis of variance (ANOVA), Pearson’s correlation, and regression analysis were used to analyze the data. A total of 20 images were reexamined after 30 days to test intra-observer error. Results: ANOVA test showed that gender had no effect on age estimation, and there was a significant correlation between age and tooth/pulp ratio (r=0.679 for right premolar, r=0.712 for left premolars, and r=0.736 for both premolars). Linear regression formulae were created based on the results and the mean differences between the estimated and actual age were reported to be 10.35±0.51, 9.17±0.54, and 8.83±0.52 for right, left, and both premolars, respectively. Intra-observer error showed no significant difference between repeated measurements. Conclusions: Tooth/pulp ratio of mandibular second premolars is a reliable and repeatable method for age estimation in Iranian population and using premolars of both sides yields the best results.

Preliminary analysis testing the accuracy of radiographic visibility of root pulp in the mandibular first molars as a maturity marker at age threshold of 18years.

Forensic age estimation, after completion of third molar mineralization, regressive features such as apposition of secondary dentin, which is seen as narrowing of the pulp space in the radiographs, can be used as an alternative. In the present study, we explored the radiographic visibility of the root pulp of mandibular first molars using stage classification of Olze et al. (Int J Legal Med 124(3):183-186, 2010) in a sample of 901 orthopantomograms (404 males and 497 females) of south Indian origin with age ranging from 14 to 22years. Descriptive statistics for the stages according to age was performed for both sexes separately. The strength and direction of the relationship between the chronological age and pulp visualization stages was tested using spearman's rho correlation statistics. The relationship between age and stage attainment showed statistical significance for both sexes. A strong, positive correlation was seen between the stage and chronological age. All males and females presenting stage 0 of root pulp visibility were younger than 18years. If stage 1 is determined, it is highly possible that an individual regardless of sex is younger than 18years. Stage 2 was attained in 79.6% males and 83.1% females who were at least 18years. One hundred percent males and 92.8% females with stage 3 were at least 18years. The accuracy of this method in mandibular first molars for estimating age threshold of 18years ranged from moderate to high. However, it is recommended to use this method in conjunction with other age estimation methods.

Evaluation of the Impact Induced by High Dietary Sucrose Concentration and Glucocorticoid Medication on Dentin Formation of Young Rats

The impact of sucrose and systemic cortisone treatment on the response of dentin was examined in an experimental rat model. After 2 months of a modified diet and/or medication period, the areas of dentin formation and dentinal caries were quantified in the mandibular molars of growing animals. The 60% sucrose diet significantly reduced dentin formation and increased dentinal caries progression. The presence of glucocorticoid medication alone reduced dentin formation. Cortisone medication in combination with sucrose diet further decreased dentin apposition. Rats receiving the control diet positively responded to the dentinal caries by increasing dentin formation to prevent pulpal exposure. The rate of dentine formation was lower in rats with high sucrose diet and predentin area was wider compared to the control group fed normal diet. The enlargement of the predentin region in sucrose diet rats reflects changes in the functionality of the odontoblasts, such as reduction of matrix synthesis and alteration of the mineralization process. These results indicate that the functional alterations in the pulpo-dentinal complex might contribute to dentinal caries progression through systemic mechanism irrespective of the causative factors.

Evaluation of the Impact Induced by High Dietary Sucrose Concentration and Glucocorticoid Medication on Dentin Formation of Young Rats

The impact of sucrose and systemic cortisone treatment on the response of dentin was examined in an experimental rat model. After 2 months of a modified diet and/or medication period, the areas of dentin formation and dentinal caries were quantified in the mandibular molars of growing animals. The 60% sucrose diet significantly reduced dentin formation and increased dentinal caries progression. The presence of glucocorticoid medication alone reduced dentin formation. Cortisone medication in combination with sucrose diet further decreased dentin apposition. Rats receiving the control diet positively responded to the dentinal caries by increasing dentin formation to prevent pulpal exposure. The rate of dentine formation was lower in rats with high sucrose diet and predentin area was wider compared to the control group fed normal diet. The enlargement of the predentin region in sucrose diet rats reflects changes in the functionality of the odontoblasts, such as reduction of matrix synthesis and alteration of the mineralization process. These results indicate that the functional alterations in the pulpo-dentinal complex might contribute to dentinal caries progression through systemic mechanism irrespective of the causative factors. Keywords: diet, sucrose, cortisone, dentin

Morphological features of tooth development and replacement in the rabbit Oryctolagus cuniculus

Dental development mechanisms in mammals are highly studied using the mouse as a biological model. However, the mouse has a single, unreplaced, set of teeth. Features of mammalian tooth replacement are thus poorly known. In this paper, we study mammalian tooth development and replacement using the European rabbit, Oryctolagus cuniculus, as a new model. Using 3D-reconstructions associated with histological sections, we obtained the complete description of the histo-morphological chronology of dental development and replacement in rabbit. We also describe in the dentin the presence of holes opening the pulp cavity in newborns. These holes are quickly repaired with a new and fast apposition of dentin from the pre-existing odontoblasts. The detailed dental morphogenesis chronology presented allows us to propose the rabbit Oryctolagus cuniculus as a suitable model to study mammalian tooth replacement.

Examination of regressive features of third molars for the purpose of age assessment in the living by means of rescaled regression analyses.

The main criterion of dental age assessment in living adolescents and young adults is the evaluation of third molars' mineralization. Concerning forensic age assessment after the completion of third molars' mineralization, apposition of secondary dentine and narrowing of the periodontal membrane as seen as decreasing radiolucent areas in the radiographs for mandibular third molars have already been described as regressive features. The present study examines the combination of both these features for the purpose of age assessment in regression analyses after rescaling the data to make it on the interval scale. To this end, a total of 1245 orthopantomograms was evaluated, taken from 606 females and 639 males in the age group of 15-40years. The apposition of secondary dentine and narrowing of the periodontal membrane as seen as decreasing radiolucent areas in the radiographs were determined for the lower third molars. The correlation of the features with the chronological age was assessed by means of rescaled regression analyses. Furthermore, regression formulas for age assessment were established. The values of the standard error of estimate ranged between 3.55 and 4.52years. In general, the rescaled regression of the examined features appears to be suited for forensic age assessment. A limitation of the present study is the comparatively low number of evaluable teeth in the examined age group. Due to an incomplete development or a lack of the mandibular third molars, only a mere half of the respective teeth could be included in the statistical analysis.

Pulp Response Capped by Brain Derived Neurotrophic Factor (BDNF)

Background: Four neurotrophins (NTFs) are a family of structurally related proteins with specific effects on the developing nervous system and non-neuronal differentiating cells. The brain-derived neurotrophic factor ( BDNF) has role in differentiation of pulp cells into mineralizing cells,and that was identified as survival factor , development and function of dental tissues.Aim of the study: The study was designed to illustrate pulp response capped by brain-derived neurotrophic factor after mechanical trauma.Materials and Method: Brain derived neurotrophic factor was used as pulp capped material for maxillary anterior teeth of (12 )rat following the mechanical traumatized proceduce.Pulp reaction was studied histologically from the first cutting procedure ,followed by interval periods (48,72,168 hours ) ,Six teeth for each period .Results: Illustrated an enhancement of pulp healing represented by newly apposition of reparative dentine with presences of active angiogenesis followed by globular minerlization that coincides with proceeding interval time.Conclusion: The study suggest that BDNF contributes in pulp healing and can be addressed to a more conservative treatment approach.

Human age estimation based on pulp volume of canines for chronological age estimation: Preliminary research

Introduction: Age estimation has an important role in the process of human identification and needs to be performed in an efficient, fast, and accurate ways. Age estimation based on the pulp cavity volume of canines was referring to the theory stated that the apposition of secondary dentine during human life could be determined as an age indicator. This study was aimed to estimate the human age based on the pulp volume of canines for chronological estimation. Methods: Forty-one canine teeth from Cone Beam Computed Tomography (CBCT) 3D image sample from Dental Hospital of the Faculty of Dentistry Universitas Padjadjaran segmented into dental pulp and enamel were prepared for measurement of pulp volume using the ITK SNAP volumetric software. Descriptive analysis of pulp volume and regression equations were generated from regression analysis of pulp volume and tested for age estimation. Result: Dentine thickness was found to be increased from adolescence age range until adulthood age range. Logarithmic regression between pulp volume was statistically significant (p < 0,001). The coefficient of determination (R2) was 0.753 with a standard deviation of 8.421. Mathematics model for estimating age was: Age = 79.523 – (18.194 x ln(Pulp Volume)). The pulp cavity and dentine thickness were decreasing along the age. The same equation was also used in the same sample. There were several differences between chronological age and estimated age approximately 8.4 years following the regression result of R2 (75.3%). The rest of the sample (24.7%) have a big difference, and this could be affected by modifying variables such as occlusal force and human error measurement procedures. Conclusion: The human age can be estimated by the pulp volume of canines.Keywords: Age estimation, pulp volume, canine, ITK-SNAP, CBCT.

The applicability of Kvaal methods and pulp/tooth volume ratio for age estimation of the Turkish adult population on cone beam computed tomography images

The contraction of the pulp chamber with secondary dentin apposition is a significant morphological dental age predictor in adults. The aim of this study is to evaluate the applicability of Kvaal’s method and pulp/tooth volume ratio on cone-beam computed tomography (CBCT) images and develop a valid method for the Turkish adult population. In this study, 211 single-rooted teeth, extracted for orthodontic and periodontal reasons, of 134 patients with ages ranging from 16 to 71 years, were used. Each sample was scanned using CBCT. According to the reported technique (Kvaal’s method), teeth were analysed on CBCT images. Additionally, pulp/tooth volume ratio was calculated using ITK-SNAP 3.4.0 software. The relationship between age and morphological variables was calculated by the Pearson correlation coefficient. Multiple linear regression models were established for each tooth, age as dependent variable, and morphological variables as independent variables. The determination of coefficients of the Kvaal’s modified regression models were found in a range from 0.296 to 0.550. The pulp volume and the pulp/tooth volume ratio showed statistically significant differences between age groups (p < 0,001). Pulp volume and pulp/tooth volume ratio is a significant index for age. Linear measurement and ratios on CBCT images were insufficient estimates of the age of the Turkish population.

First analysis of life history and season of death of a South American gomphothere

Excavations associated with wastewater treatment facilities in the Santiago Basin of Chile uncovered remains of an adult male Stegomastodon platensis in Pleistocene fluvial sediments. The specimen included a skull with both tusks still in their alveoli. A small sample block of dentin and cementum was excised from the right tusk for analysis of compositional and structural variation recorded in the sequence of dentin layers. The sample was analyzed using serial isotope assays, microCT, and measurement of dentin increments in thin sections. These procedures allowed us to recover life history information relating to the final four years of life. Analyses show seasonal variation in composition, density, and growth rate, permitting identification of years. MicroCT features appear to recur semiannually, which has not been observed previously in proboscidean tusks; these features are interpreted to correspond to the winter-spring boundary and some other aspect of environment or behavior recurring within each year. Average annual apposition of dentin within the tusk is 10.4 mm for complete years studied, suggesting that this individual was healthy leading up to the final year of life. Recurrent periods of low rate of apposition measured in weekly dentin increments that formed during the summer are interpreted as representing periods of musth. Using the location of microCT features, annual appositional thickness, and the pattern of weekly growth within the final year of life, we interpret the season of death for this individual as being within the early autumn.