RESUMEN
BACKGROUND: The neonatal line (NL) is an important issue in forensic odontology. It is the sign of a developmental birth defect, which is caused by the effect of metabolic stress on tooth structures when the fetus passes to extrauterine life. AIMS: The aim of this research is to determine the existence and thickness of NL in teeth, as it is a legal necessity to indicate the signs of viability at birth in a forensic examination of a fetus or infant case. STUDY DESIGN AND SUBJECTS: This research was conducted on 48 lower left and right lateral teeth, which were taken from 24 autopsy cases (46% female and 54% male). Left lateral teeth were sectioned in a vertical plane and right lateral teeth were sectioned in a horizontal plane. The NL thickness was measured with a scanning electron microscope (SEM). These cases comprised three conditions as: 70.3% normal birth, 16.7% caesarean sections, and 12.5% still birth cases under the legal and ethical permission. OUTCOME MEASURES: The mean NL thickness of normal birth cases was higher than caesarean cases as 7.7µm and 2.5µm, respectively. RESULTS AND CONCLUSIONS: The results showed a statistical significance between all birth conditions. NL does not exist in still birth cases (p<0.001). Not only is the presence of NL a sign of live birth, but also its thickness is an indicator of the delivery mode where NL thickness of normal birth was found thicker than the caesarean cases.
Asunto(s)
Parto Obstétrico/métodos , Esmalte Dental/embriología , Diente Primario/anatomía & histología , Diente Primario/embriología , Cesárea , Esmalte Dental/anatomía & histología , Femenino , Humanos , Recién Nacido , Masculino , Microscopía Electrónica de Rastreo , Embarazo , Mortinato , Diente Primario/ultraestructuraRESUMEN
Forensic identification comprises legal, social, ethical, and religious aspects where age detection is an important factor. When the case is a fetus or infant, recording various measurements of the body, head, and teeth is essential. The aim of this research is to evaluate the effects of different tooth and body measurements and their implications on the age estimation of fetuses and infants. This research was performed on 96 fetus and infant incisor teeth taken from 24 autopsy cases (54 % males and 46 % females) where age of the subjects were within the range of prenatal 16 weeks to postnatal 72 weeks. The data were statistically processed by regression analysis via curve estimations. According to the results, growing patterns of the head circumference (HC) and the upper central tooth measurements indicate a strong relationship, where there is no significant difference for both sexes. The growth patterns of all variables showed a linear function to a certain age (approximately 56 weeks pre-plus postnatal); the tooth height (TH) slightly increases until the closure of the root apex, and the HC gradually stabilizes in time, therefore a log-linear relation was found considerable. The results revealed eight age estimation formulas, including the combination of HC with the labiolingual, mesiodistal (MD), crown height, and TH measurements. Among these, only MD can be applied to a living. In conclusion, tooth and head measurements are found to be the main factors of age estimation formulas.
Asunto(s)
Determinación de la Edad por el Esqueleto/métodos , Determinación de la Edad por los Dientes/métodos , Incisivo/embriología , Cráneo/embriología , Cefalometría , Femenino , Desarrollo Fetal , Antropología Forense , Odontología Forense , Humanos , Masculino , Proyectos Piloto , Análisis de RegresiónRESUMEN
Factor V Leiden (FVL) is the most common monogenic disorder that causes activated protein C (APC) resistance, creating hyper-coagulation. The mutation shows an uneven geographic distribution, significantly high in European populations. The mutation is believed to have originated approximately 20 000 years ago probably from a geographic region close to Anatolia. This fact makes it noteworthy to search for the mutation in ancient populations that once lived in this area. One of these civilizations, Urartu was centered around Van Lake in Eastern Turkey. The archeological remains from the excavations of the region are dated back to 1000 BC. Teeth, taken from the excavations of Van Yoncatepe fortress, were taken into DNA analysis considering all the precautions for ancient DNA analysis. Multiplex STR (Short Tandem Repeats) analysis were performed both to determine the gender of the samples and to conclude that the samples are preserved from modern DNA contamination. After getting an 80% amplification success for amelogenin, a melting curve analysis using lightcycler was performed to determine the FVL genotype of each sample. Of the 60 samples, 1 gave a positive amplification result for FV gene and was found to be heterozygous. To date, the age of this mutation was estimated based on statistical calculations using haplotype frequencies; here for the first time, we report FVL in an ancient population of 3000 years.
Asunto(s)
ADN/genética , Factor V/genética , Fósiles , Diente/química , Resistencia a la Proteína C Activada/genética , Arqueología , ADN/química , Factor V/metabolismo , Pruebas Genéticas , Humanos , Mutación Puntual , TurquíaRESUMEN
Age at time of death for a fetus or infant is an important issue in the field of forensic science. Dental development can give an accurate measure of infant and fetal age and current literature does not include any studies of dental age from central incisor development. The objective of this study is to determine the age of deceased fetuses and infants by examining metric tooth development of central incisors in deceased fetuses and infants. Five dimensions of 76 maxillary and mandibular central incisors were measured: mesio-distal (MD), bucco-lingual (BL), crown height (CH), crown thickness (CT), and root height (RH). The results showed that 44.45+/-0-2 weeks is a sectional time for age calculations, which corresponds to 40 weeks from conception plus 4 to 5 weeks after birth. Four ATA entitled age formulas are derived to give the relation of age with tooth dimensions before and after 44.45 weeks [ATA is the special name given to the honor of the great Turkish leader Mustafa Kemal Atatürk (1881-1938)]. Age estimation can be calculated from these formulas with an accuracy of the age +/-0-2 weeks. Also, calcification time can be determined from ATA formulas. In conclusion, the age of fetuses and infants can be assessed by the measurements of a single central incisor. According to this research, when estimating age during identification studies, forensic researchers must take into consideration the period of embryonic human growth and development.
Asunto(s)
Determinación de la Edad por los Dientes/métodos , Incisivo/anatomía & histología , Diente Primario/anatomía & histología , Análisis de Varianza , Femenino , Feto , Odontología Forense , Humanos , Lactante , Recién Nacido , Modelos Lineales , Masculino , Raíz del Diente/anatomía & histologíaRESUMEN
STATEMENT OF PROBLEM: Surface treatment methods used for resin bonding to conventional silica-based dental ceramics are not reliable for zirconium-oxide ceramics. PURPOSE: The aim of this study was to compare the effects of airborne-particle abrasion, silanization, tribochemical silica coating, and a combination of bonding/silane coupling agent surface treatment methods on the bond strength of zirconium-oxide ceramic to a resin luting agent. MATERIAL AND METHODS: Sixty square-shaped (5 x 5 x 1.5 mm) zirconium-oxide ceramic (Cercon) specimens and composite resin (Z-250) cylinders (3 x 3 mm) were prepared. The ceramic surfaces were airborne-particle abraded with 125-microm aluminum-oxide (Al(2)O(3)) particles and then divided into 6 groups (n = 10) that were subsequently treated as follows: Group C, no treatment (control); Group SIL, silanized with a silane coupling agent (Clearfil Porcelain Bond Activator); Group BSIL, application of the adhesive 10-methacryloyloxydecyl dihydrogen phosphate monomer (MDP)-containing bonding/silane coupling agent mixture (Clearfil Liner Bond 2V/ Porcelain Bond Activator); Group SC, silica coating using 30-microm Al(2)O(3) particles modified by silica (CoJet System); Group SCSIL, silica coating and silanization (CoJet System); and Group SCBSIL, silica coating and application of an MDP-containing bonding/silane coupling agent mixture (Clearfil Liner Bond 2V/Porcelain Bond Activator). The composite resin cylinders were bonded to the treated ceramic surfaces using an adhesive phosphate monomer-containing resin luting agent (Panavia F). After the specimens were stored in distilled water at 37 degrees C for 24 hours, their shear bonding strength was tested using a universal testing machine at a crosshead speed of 0.5 mm/min. Debonded specimen surfaces were examined with a stereomicroscope to assess the mode of failure, and the treated surfaces were observed by scanning electron microscopy. Bond strength data were analyzed using 1-way analysis of variance and the Duncan test (alpha = .05). RESULTS: The bond strengths (mean +/- SD; MPa) in the groups were as follows: Group C, 15.7 +/- 2.9; Group SIL, 16.5 +/- 3.4; Group BSIL, 18.8 +/- 2.8; Group SC, 21.6 +/- 3.6; Group SCSIL, 21.9 +/- 3.9; and Group SCBSIL, 22.9 +/- 3.1. The bond strength was significantly higher in Group SCBSIL than in Groups C, SIL, and BSIL (P<.001), but did not differ significantly from those in Groups SC and SCSIL. Failure modes were primarily adhesive at the interface between zirconium and the resin luting agent in Groups C and SIL, and primarily mixed and cohesive in Groups SC, SCSIL, and SCBSIL. CONCLUSION: Tribochemical silica coating (CoJet System) and the application of an MDP-containing bonding/silane coupling agent mixture increased the shear bond strength between zirconium-oxide ceramic and resin luting agent (Panavia F).
Asunto(s)
Cerámica/química , Recubrimiento Dental Adhesivo , Materiales Dentales/química , Cementos de Resina/química , Circonio/química , Abrasión Dental por Aire/métodos , Óxido de Aluminio/química , Resinas Compuestas/química , Humanos , Ensayo de Materiales , Metacrilatos/química , Microscopía Electrónica de Rastreo , Resistencia al Corte , Silanos/química , Dióxido de Silicio/química , Estrés Mecánico , Propiedades de Superficie , Temperatura , Factores de Tiempo , Agua/químicaRESUMEN
STATEMENT OF PROBLEM: Available information on the dimensions of the enamel and pulp tissues of tooth structure, as well as their correlation with chronologic age, is limited. However, this information is a significant determinate in planning the tooth reduction for a porcelain laminate veneer (PLV) restoration. PURPOSE: This study examined variations in tooth enamel thickness and its correlation with chronologic age as it relates to available tooth substrate for PLV restorations. MATERIAL AND METHODS: Forty human maxillary central incisors extracted from patients within the age range of 30 to 69 years were used to evaluate the thickness of tooth layers. Measurements were made for the following tooth areas using scanning electron microscopy (SEM): facial enamel thickness at 1, 3, and 5 mm above the cemento-enamel junction (CEJ), palatal enamel thickness at 5 mm above the CEJ, facial and palatal enamel thickness at the incisal edge, maximum facial-palatal (MFP) width at incisal edge, physiologic secondary dentin (PSD) height, facial-cervical enamel-pulp (FCEP) distance, and the incisal edge enamel-pulp (IEP) distance. The relationship between thickness and age was evaluated with a regression analysis (alpha=.05). RESULTS: Significant differences (P<.001) were observed in all of the relationships between tooth thicknesses and chronological age. Outcome variables of enamel thickness related to age showed a steady decrease, beginning at approximately age 50. Mean values of facial enamel thickness at 1, 3, and 5 mm above the CEJ were 0.31 +/- 0.01, 0.54 +/- 0.01, and 0.75 +/- 0.02 mm, respectively, for the age range of 30 to 69 years. The thickness of maximum incisal width (R(2) = 0.95), PSD height (R(2) = 0.76), and IEP distance (R(2) = 0.99) indicated that all are subject to an increase in relation to age. CONCLUSION: Facial enamel thickness above the CEJ decreases, while MFP increases in relation to age. The PSD height and IEP distance also increased with age.