Dental ontogeny of harp seals, Phoca groenlandica

1987 ◽  
Vol 65 (6) ◽  
pp. 1425-1434 ◽  
Author(s):  
R. E. A. Stewart ◽  
B. E. Stewart
Keyword(s):  
Permanent Tooth ◽  
Permanent Dentition ◽  
Tooth Eruption ◽  
Harp Seal ◽  
Permanent Teeth ◽  
Deciduous Teeth ◽  
Deciduous Dentition ◽  
Phoca Groenlandica ◽  
Number Of Teeth ◽  
Dental Ontogeny

Harp seal fetuses and neonates were examined to determine the development, resorption, and eruption characteristics of deciduous and permanent dentition. Early September fetuses had recently formed, deciduous teeth only. By early December the deciduous dentition was robust and enameled. Permanent teeth were also present. In late December the roots of the deciduous teeth were being resorbed and the permanent dentition was larger and better developed. About 80% of the deciduous teeth were resorbed by birth in March. The rest were resorbed or shed after birth. The pattern of permanent tooth eruption was not correlated with pup age but the total number of teeth erupted increased significantly with increasing pup age, from 38% in newborns to 100% in weaned pups about 3 weeks old. The neonatal line formed at birth rather than at weaning or the onset of moult.

scholarly journals Hardness and modulus of elasticity of primary and permanent teeth after wear against different dental materials

2015 ◽  
Vol 09 (04) ◽  
pp. 587-593 ◽  
Author(s):  
Rodrigo Galo ◽  
Marta Maria Martins Giamatei Contente ◽  
Daniel Galafassi ◽  
Maria Cristina Borsatto
Keyword(s):  
Modulus Of Elasticity ◽  
Artificial Saliva ◽  
Dental Materials ◽  
Permanent Tooth ◽  
Composite Resins ◽  
Permanent Teeth ◽  
Deciduous Teeth ◽  
Fissure Sealant ◽  
Plate Design ◽  
Before And After

ABSTRACT Objectives: The purpose of this study was to determine the Young's modulus and the hardness of deciduous and permanent teeth following wear challenges using different dental materials. Materials and Methods: Wear challenges were performed against four dental materials: A resin-based fissure sealant (Fluoroshield®), a glass ionomer based fissure sealant (Vitremer®), and two microhybrid composite resins (Filtek Z250 and P90®). Using the pin-on-plate design, a deciduous or a permanent tooth was made into a pin (4 mm × 4 mm × 2 mm) working at a 3 N vertical load, 1 Hz frequency, and 900 cycles (15 min) with Fusayama artificial saliva as a lubricant. Before and after the tribological tests, the hardness and elasticity modulus of the tooth samples were measured by creating a nanoindentation at load forces up to 50 mN and 150 mN. All of the results were statistically analyzed using ANOVA and post-hoc Duncan's tests (P < 0.05). Results: No difference in hardness was encountered between deciduous and permanent teeth (P < 0.05) or modulus of elasticity (P < 0.05) before or after the wear challenges for all of the dental materials tested. Conclusions: Wear challenges against the studied dental materials did not alter the properties of permanent or deciduous teeth after the application of a 3 N load.

Effect of Prenatal and Postnatal Fluoride on the Human Deciduous Dentition. A Literature Review

1989 ◽  
Vol 3 (2) ◽  
pp. 168-176 ◽  
Author(s):  
I. Gedalia ◽  
L. Shapira
Keyword(s):  
Crystal Surface ◽  
Permanent Dentition ◽  
Matrix Proteins ◽  
Deciduous Teeth ◽  
Maturation Stage ◽  
Fetal Life ◽  
Deciduous Dentition ◽  
Partial Protection ◽  
Fluoride Accumulation ◽  
Enamel Mineralization

Fluoride passes from the mother to fetal teeth. Much of the fluoride is taken up in secretory enamel, probably by the forming mineral apatite crystals. Some is retained with residual proteins. The low concentration of fluoride in the inner enamel is incorporated mainly during the secretory stage, while the enhanced concentration in the surface enamel is produced during the much longer maturation stage. Mature, hard enamel is generally absent during fetal life. The clinical question is whether prenatal fluoride imparts an additional benefit to the universally accepted effect of postnatal fluoride. In general, surface enamel fluoride levels of deciduous teeth increase with increasing pre- and postnatal fluoride administration. A consistent level of caries protection has been reported with pre- and postnatal administration of fluoride unrelated to the acquisition of fluoride in the surface enamel. Many children develop enamel opacities in their deciduous dentition related by various factors to enamel mineralization disturbances in drinking water areas even low in fluoride. Accumulation of fluoride due to an increased fluoride intake is a feature of fluorosed enamel in the deciduous as well as permanent dentition. The resulting mature fluorosed enamel retains a relatively high proportion of immature matrix proteins onto the crystal surface. The degree of fluorosis of the deciduous dentition is less compared with that of the permanent dentition, due probably to a partial protection afforded by the maternal loss of fluoride, formerly known as the "placental barrier".

Association Between Genetic Polymorphisms in Metaloproteinases of the Matrix and Delayed Tooth Emergence: A Cross-sectional Study

2019 ◽  
Vol 10 (2) ◽  
pp. 91-96
Author(s):  
Silvane Silva Evangelista ◽  
Juliana Arid ◽  
Katia Regina Felizardo Vasconcelos ◽  
Giuseppe Valduga Cruz ◽  
André Luiz Tannus Dutra ◽  
...  
Keyword(s):  
Genetic Polymorphisms ◽  
Cross Sectional Study ◽  
Permanent Tooth ◽  
Tooth Eruption ◽  
Permanent Teeth ◽  
Fisher Exact Test ◽  
Genotype Distribution ◽  
Sectional Study ◽  
Cross Sectional ◽  
Allele Distribution

Background and Aims: Animal models have been demonstrating that MMPs have an important function in the tooth eruption process. The aim of this study was to evaluate the association between genetic polymorphisms in MMP8 and MMP13 and delayed tooth eruption of permanent teeth. Materials and Methods: This cross-sectional study selected 216 children, 9- to 12-year-old, from public schools at Manaus, Amazonas, Brazil. During oral clinical examination, each permanent tooth emerged in the oral cavity was evaluated. Children were considered with delayed tooth eruption when at least one permanent tooth was delayed and were classified in 2 groups: children “with delayed tooth emergency” and “without delayed tooth emergency.” Saliva samples were collected from DNA extraction. The genetic polymorphisms rs17099443 and rs3765620 in MMP8, and rs478927 and rs2252070 in MMP13 were genotyped. Statistical Analysis: PLINK V1.07 ( http://pngu.mgh.harvard.edu/purcell/plink/ ) and GraphPad Prism 5.0 (San Diego, CA, USA) were used. The c2 or Fisher exact test was used to calculate genotypes and alleles distributions. To compare the mean number of delayed teeth according to genotypes, the Kruskal-Wallis test with multiple comparison Dunn test was used. The established alpha for all comparisons was .05. Results: The polymorphism rs17099443 in MMP8 was associated with delayed tooth eruption in the genotype distribution ( P = .05). In the allele distribution, the C allele was underrepresented in children with delayed tooth eruption ( P = .01; OR = 0.61, 95% confidence interval, 0.41–0.9). Conclusion: The genetic polymorphism rs17099443 in MMP8 is associated with delayed tooth eruption.

Eruption of Permanent Teeth in Mongoloid Children and Their Sibs

1973 ◽  
Vol 52 (6) ◽  
pp. 1202-1208 ◽  
Author(s):  
Gerald Orner
Keyword(s):  
Permanent Dentition ◽  
Tooth Eruption ◽  
Permanent Teeth ◽  
Normal Children ◽  
Tooth Type ◽  
Consistent Tendency

Eruption constants for the permanent dentition were determined in 212 mongoloid children and 124 of their unaffected sibs. Eruption of the permanent teeth in sibs was like that of other normal children. Mongoloid children resembled their sibs in general characteristics of tooth eruption, but showed a consistent tendency toward later mean ages of eruption for each tooth type.

Implantation of octacalcium phosphate collagen composites (OCP/Col) after extraction of canine deciduous teeth achieved undisturbed permanent tooth eruption

2016 ◽  
Vol 72 ◽  
pp. 179-186 ◽  
Author(s):  
Naofumi Kanda ◽  
Keiko Matsui ◽  
Tadashi Kawai ◽  
Hiroshi Edamatsu ◽  
Yuji Tanuma ◽  
...  
Keyword(s):  
Octacalcium Phosphate ◽  
Permanent Tooth ◽  
Tooth Eruption ◽  
Deciduous Teeth

Some quantitative dental characteristics of the chimpanzee, gorilla and orang-outang

1950 ◽  
Vol 234 (616) ◽  
pp. 471-484 ◽  
Keyword(s):  
Standard Deviation ◽  
Standard Error ◽  
Statistical Data ◽  
Age Groups ◽  
Permanent Dentition ◽  
Small Samples ◽  
Permanent Teeth ◽  
Deciduous Teeth ◽  
The Mean ◽  
Made In

Measurements have been taken of the crowns of the teeth of seventy-nine chimpanzees, eighty-nine gorillas and sixty-three orang-outangs. Basic statistical data, comprising the mean, the number of skulls, the standard deviation and the standard error of the mean, are presented for forty-eight dimensions and indices of the deciduous teeth and for seventy-eight of those of the permanent dentition of each type of ape. A separation between the sexes has been made in the case of the permanent teeth. Further separation has been made into age groups, where necessitated by changes in dimensions due to wear. Even with the small samples resulting from these subdivisions, the standard error is seldom greater than 4 % of the mean, and therefore the figures obtained are reliable estimates of the variability of the teeth of apes. The data provide a basis for quantitative comparisons between the teeth of existing and fossil anthropoids.

scholarly journals Management of an Impacted Dilacerated Permanent Maxillary Central Incisor

2017 ◽  
Vol 2 (1) ◽  
pp. 44-46
Author(s):  
Puneet Goenka ◽  
Swati Agarwal ◽  
Vijay Lakshmi ◽  
Yogita Chaturvedi ◽  
Mitakshara Nirwan
Keyword(s):  
Dentigerous Cyst ◽  
Permanent Dentition ◽  
Permanent Teeth ◽  
Deciduous Teeth ◽  
Maxillary Incisor ◽  
Histopathologic Examination ◽  
Central Incisor ◽  
Common Cause ◽  
Maxillary Central Incisor ◽  
History Of

ABSTRACT The impacted maxillary incisor is rare and detrimental for problems related to esthetics and occlusion in permanent dentition stage. The diagnosis of an impacted incisor with dilaceration refers to a dental deformity characterized by an angulation between the crown and the root, causing noneruption of the incisor. The most common cause of dilaceration in a tooth is trauma to its primary predecessor like avulsions, intrusions, or gross displacement of primary incisors. This study presents a case with overretained mobile deciduous teeth that were diagnosed radiographically with an impacted dilacerated maxillary central incisor surrounded by a large radiolucency. History of trauma to the same region was given at the age of 1 year. On examination, multiple missing permanent teeth were noted. The management of the case was carried out by surgical enucleation and histopathologic examination confirmed diagnosis of an infected dentigerous cyst. How to cite this article Agarwal S, Goenka P, Lakshmi V, Chaturvedi Y, Nirwan M. Management of an Impacted Dilacerated Permanent Maxillary Central Incisor. J Mahatma Gandhi Univ Med Sci Tech 2017;2(1):44-46.

scholarly journals A fool’s mission? A test of three common assumptions in dental metric analyses

2018 ◽  
Vol 26 (3) ◽  
pp. 16-30 ◽  
Author(s):  
Brian E. Hemphill
Keyword(s):  
Permanent Tooth ◽  
Permanent Dentition ◽  
Permanent Teeth ◽  
Human Populations ◽  
Tooth Size ◽  
Sex Dimorphism ◽  
Unit Of Analysis ◽  
Environmental Perturbations ◽  
Tooth Type ◽  
Males And Females

Three aspects of metric variation in the permanent dentition of humans are often simply accepted as true. The first is that formation of the permanent dentition occurs within morphogenetic fields broadly associated with tooth type and jaw. The second is that dental development of among females is characterized by a higher degree of ontogenetic buffering relative to males. The third is that expression of sex dimorphism in permanent tooth size is expressed uniformly among well-nourished human populations. This study tests these assumptions through an examination of mesiodistal and buccolingual dimensions of all non-canine permanent teeth, except third molars, among 2,709 living individuals of 15 ethnic groups from South Asia. With sexes pooled, only one in four contrasts of variance among key versus distal teeth within dental fields are significantly heterogeneous, while one in four contrasts yield higher levels of variance among key teeth relative to their distal counterparts within a dental field. Such results weaken considerably orthodox applications of Butler’s dental field theory. When samples are the unit of analysis, male samples are marked by fewer dental fields with significantly heterogeneous levels of variance between key and distal members, while males and females are affected equally by significantly heterogeneous variation between key and distal members when dental fields are the unit of analysis. Such results suggest males and females are equally buffered against environmental perturbations that affect odontometric variation. One-way ANOVA indicates that a tooth’s position within a dental field ac-counts for 15.5% to 23.1% of the observed varia-tion in tooth size, while two-way ANOVA reveals that when sex is added as a second factor, the percentage of variance in tooth size explained increases from 16.7% to 30.8%, an improvement of 27.2%. Such results indicate sex dimorphism in tooth size varies in both patterning and in magnitude among these samples, thereby explaining why discriminant functions developed for one population often perform more poorly when applied to other populations.

Deciduous dentition and dental eruption sequence in Interatheriinae (Notoungulata, Interatheriidae): implications in the systematics of the group

2021 ◽  
pp. 1-25
Author(s):  
Mercedes Fernández ◽  
Juan C. Fernicola ◽  
Esperanza Cerdeño
Keyword(s):  
Permanent Tooth ◽  
Permanent Dentition ◽  
New Combination ◽  
Deciduous Dentition ◽  
Crown Height ◽  
Dental Eruption ◽  
Posterior Direction ◽  
Anterior Direction ◽  
Posterior Anterior ◽  
Anterior Posterior

Abstract Studies focused on deciduous dentition, ontogenetic series, and tooth eruption and replacement patterns in fossil mammals have lately increased due to the recognized taxonomic and phylogenetic weight of these aspects. A study of the deciduous and permanent dentition of Interatherium and Protypotherium (Interatheriinae) is presented, based mainly on unpublished materials. Deciduous cheek teeth are brachydont and placed covering the apex of the respective permanent tooth; in addition, some morphological and metrical differences are observed along the crown height. Five dental ontogenetic stages are distinguished among the juvenile specimens on the basis of the degree of wear, the replacement of the deciduous premolars, and the eruption of the molars. The crown height and the wear degree of different Interatheriinae taxa show: (1) eruption pattern of molars in an anterior–posterior direction (M/m1 to M/m3); (2) pattern of replacement of deciduous premolars and eruption of permanent premolars in a posterior–anterior direction (dP/dp4 to dP/dp2 and P/p4 to P/p2); and (3) eruption of M/m3 before the replacement of dP/dp4. Results allow evaluating the diagnostic dental characteristics used to describe some interatheriines, as well as reinterpreting some taxonomic assumptions: the holotype of Protypotherium diversidens Ameghino, 1891 is recognized as a juvenile of another species of the genus, and the species is not validated, considering it as Protypotherium sp.; the holotype of Eudiastatus lingulatus Ameghino, 1891 falls in the variability of Protypotherium, becoming P. lingulatus new combination, tentatively maintaining the species and implying the synonymy between Eudiastatus and Protypotherium; and the holotype of Eopachyrucos ranchoverdensis Reguero, Ubilla, and Perea, 2003 is reinterpreted as bearing deciduous premolars.

scholarly journals Fused primary first mandibular macromolar with a unique relation to its permanent successors: A rare tooth anomaly

2013 ◽  
Vol 07 (02) ◽  
pp. 239-242 ◽  
Author(s):  
Abhishek Dhindsa ◽  
Shalini Garg ◽  
S. G. Damle ◽  
Shireen Opal ◽  
Tavleen Singh
Keyword(s):  
Permanent Tooth ◽  
Permanent Dentition ◽  
Dental Anomalies ◽  
Supernumerary Tooth ◽  
Deciduous Dentition ◽  
Primary Molar ◽  
Anterior Teeth ◽  
Mandibular First Premolar ◽  
Double Teeth ◽  
Fused Tooth

ABSTRACTDental anomalies of number and forms may occur in the primary and permanent dentition. Various terms have been used to describe dental twinning anomalies: Germination, fusion, concrescence, double teeth, conjoined teeth, twinned teeth, geminifusion, and vicinifusion. Fused tooth is a developmental anomaly that is seen more frequently in the primary than the permanent dentition. Double tooth involving deciduous anterior teeth is found mostly in the mandible.Very few cases of nonsyndromic double primary molar have been reported in the literature. The succeeding permanent tooth is often found missing congenitally in the same region. This article reports a very rare unilateral occurrence of an anomalous, primary mandibular first macromolar formed by fusion with a dysmorphic premolar like supernumerary tooth in deciduous dentition period. Instead of agenesis of succedaneous tooth, the double tooth has been succeeded by normally developing mandibular first premolar in the same region.

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