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Journal of Anatomy Mar 2016Choristoderes are a group of extinct freshwater reptiles that were distributed throughout Laurasia from the Middle Jurassic to the Miocene. They are inferred to have had...
Choristoderes are a group of extinct freshwater reptiles that were distributed throughout Laurasia from the Middle Jurassic to the Miocene. They are inferred to have had a lifestyle similar to that of extant gavialid crocodiles, but they differed from crocodiles in retaining an extensive palatal dentition. All choristoderes had teeth on the vomers, palatines and pterygoids, and teeth are rarely present on the parasphenoid. Palatal teeth are conical, as in the marginal dentition, and form longitudinal and transverse rows. Detailed examination of different genera shows that the orientation of the palatal tooth crowns changes with their position on the palate, supporting the view that they are involved in intra-oral food transportation, presumably in combination with a fleshy tongue. Moreover, observed variation in palatal tooth shape and the width of palatal tooth batteries may provide additional clues about diet. The European Simoedosaurus lemoinei has sharper palatal teeth than its North American counterpart, S. dakotensis, suggesting a preference for softer prey - a conclusion consistent with the more gracile teeth and narrower snout.
Topics: Animals; Dentition; Extinction, Biological; Fossils; Palate; Phylogeny; Reptiles; Tooth
PubMed: 26573112
DOI: 10.1111/joa.12414 -
Scientific Reports Dec 2022Dentitions of the sympatric herbivorous dinosaurs Hungarosaurus (Ankylosauria, Nodosauridae) and Mochlodon (Ornithopoda, Rhabdodontidae) (Santonian, Hungary) were...
Dentitions of the sympatric herbivorous dinosaurs Hungarosaurus (Ankylosauria, Nodosauridae) and Mochlodon (Ornithopoda, Rhabdodontidae) (Santonian, Hungary) were analysed to investigate their dietary ecology, using several complementary methods-orientation patch count, tooth replacement rate, macrowear, tooth wear rate, traditional microwear, and dental microwear texture analysis (DMTA). Tooth formation time is similar in Hungarosaurus and Mochlodon, and traditional and DMTA microwear features suggest low-browsing habits for both taxa, consistent with their inferred stances and body sizes. However, Mochlodon possesses a novel adaptation for increasing dental durability: the dentine on the working side of the crown is double the thickness of that on the balancing side. Moreover, crown morphology, enamel thickness, macrowear orientation, and wear rate differ greatly between the two taxa. Consequently, these sympatric herbivores probably exploited plants of different toughness, implying dietary selectivity and niche partitioning. Hungarosaurus is inferred to have eaten softer vegetation, whereas Mochlodon likely fed on tougher material. Compared to the much heavier, quadrupedal Hungarosaurus, the bipedal Mochlodon wore down more than twice as much of its crown volume during the functional life of the tooth. This heavy tooth wear might correlate with more intensive food processing and, in turn, could reflect differences in the metabolic requirements of these animals.
Topics: Animals; Dinosaurs; Herbivory; Dentition; Sympatry; Tooth Wear
PubMed: 36460688
DOI: 10.1038/s41598-022-24816-z -
Developmental Dynamics : An Official... May 2022Sturgeons belong to an early-branching lineage often used as a proxy of ancestor-like traits of ray-finned fishes. However, many features of this lineage, such as the...
BACKGROUND
Sturgeons belong to an early-branching lineage often used as a proxy of ancestor-like traits of ray-finned fishes. However, many features of this lineage, such as the transitory presence and the eventual loss of dentition, exemplify specializations that, in fact, provide important information on lineage-specific evolutionary dynamics.
RESULTS
Here, we introduce a detailed overview of the dentition during the development of the sterlet sturgeon. The dentition is composed of tooth fields at oral, palatal, and anterior pharyngeal regions. Oral fields are single-rowed, non-renewed and are shed early. Palatal and pharyngeal fields are multi-rowed and renewed from the adjacent superficial epithelium without the presence of the successional dental lamina. The early loss of oral fields and subsequent establishment of palatal and pharyngeal fields leads to a translocation of the functional dentition from the front to the rear of the oropharyngeal cavity until the eventual loss of all teeth.
CONCLUSIONS
Our survey shows the sterlet dentition as a dynamic organ system displaying differential composition at different time points in the lifetime of this fish. These dynamics represent a conspicuous feature of sturgeons, unparalleled among extant vertebrates, and appropriate to scrutinize developmental and evolutionary underpinnings of vertebrate odontogenesis.
Topics: Animals; Biological Evolution; Dentition; Fishes; Odontogenesis; Tooth; Vertebrates
PubMed: 34846759
DOI: 10.1002/dvdy.444 -
The Angle Orthodontist 1994The late mixed dentition stage of development, after the eruption of the first premolars, is a favorable time to start treatment to resolve crowding. This protocol... (Review)
Review
The late mixed dentition stage of development, after the eruption of the first premolars, is a favorable time to start treatment to resolve crowding. This protocol offers the clinician choices. If nonextraction treatment is preferable, arch length preservation can provide the space for alignment in approximately 75% of all patients with crowding. If extraction treatment is indicated, the first premolars are available.
Topics: Bicuspid; Dental Arch; Dentition, Mixed; Humans; Incisor; Malocclusion; Mandible; Orthodontics, Corrective; Serial Extraction; Time Factors; Tooth Eruption
PubMed: 7864462
DOI: 10.1043/0003-3219(1994)064<0415:CTOT>2.0.CO;2 -
Hua Xi Kou Qiang Yi Xue Za Zhi = Huaxi... Aug 2023This study aimed to construct the finite element model of the mandibular first molar with the invisible appliance and explore the dentition movement characteristics of...
OBJECTIVES
This study aimed to construct the finite element model of the mandibular first molar with the invisible appliance and explore the dentition movement characteristics of the mandibular first molar when using micro-implant anchorage and different initial positions of the first molar.
METHODS
Models of the mandible, tooth, periodontal membrane, and invisible appliance were constructed using cone beam computed tomography (CBCT) data. The two groups were divided into the non-anchorage group and the micro-implant group (between the roots of the first molar and the second molar) based on whether the elastic traction of the micro-implant was assisted or not. The two groups were divided into the following conditions based on the starting position of the first molar: Working condition 1: the distance between the first molar and the second premolar was 0 mm; working condition 2: the distance between the first molar and the second premolar was 1 mm; working condition 3: the distance between the first molar and the second premolar was 2 mm; working condition 4: the distance between the first molar and the second premolar was 3 mm. The data characte-ristics of total displacement and displacement in each direction of dentition were analyzed.
RESULTS
In the non-ancho-rage group, all the other teeth showed reverse movement except for the first molar which was moved distally. Meanwhile, in the micro-implant group, except for a small amount of mesial movement of the second molar in wor-king condition 1, the whole dentition in other working conditions presented distal movement and anterior teeth showed lingual movement, among which the distal displacement of the first molar in working condition 4 was the largest. With the change of the initial position of the first molar to the distal, the movement of the first molar to the distal, the premolar to the mesial, and the anterior to the lip increased, while the movement of the second molar to the mesial decreased.
CONCLUSIONS
The micro-implant can effectively protect the anterior anchorage, increase the expression rate of molar distancing, and avoid the round-trip movement of the second molar. The initial position of the first molar movement is related to the amount of distancing and the remaining tooth movement.
Topics: Finite Element Analysis; Molar; Bicuspid; Periodontal Ligament; Tooth Movement Techniques; Orthodontic Appliances, Removable
PubMed: 37474472
DOI: 10.7518/hxkq.2023.2023021 -
Journal of Anatomy Jan 2017The presence of a palatal dentition is generally considered to be the primitive condition in amniotes, with each major lineage showing a tendency toward reduction. This...
The presence of a palatal dentition is generally considered to be the primitive condition in amniotes, with each major lineage showing a tendency toward reduction. This study highlights the variation in palatal tooth arrangements and reveals clear trends within the evolutionary history of tetrapods. Major changes occurred in the transition between early tetrapods and amphibians on the one hand, and stem amniotes on the other. These changes reflect the function of the palatal dentition, which can play an important role in holding and manipulating food during feeding. Differences in the arrangement of palatal teeth, and in their pattern of loss, likely reflect differences in feeding strategy but also changes in the arrangement of cranial soft tissues, as the palatal dentition works best with a well-developed mobile tongue. It is difficult to explain the loss of palatal teeth in terms of any single factor, but palatal tooth patterns have the potential to provide new information on diet and feeding strategy in extinct taxa.
Topics: Animals; Biological Evolution; Dentition; Extinction, Biological; Palate; Phylogeny; Tooth; Vertebrates
PubMed: 27542892
DOI: 10.1111/joa.12534 -
International Journal of Environmental... Mar 2022Thin gingival phenotype (GPh) may contribute to periodontal tissue breakdown and recession development. Thus, the early identification of thin GPh in children can allow...
UNLABELLED
Thin gingival phenotype (GPh) may contribute to periodontal tissue breakdown and recession development. Thus, the early identification of thin GPh in children can allow proper preventive care and the identification of children at risk during orthodontic treatment. The present long-term study aimed to monitor GPh changes, i.e., thickness (GT) and width of attached gingiva (AGW) during the early transitional dentition phase, as well as its potential associations with the mucogingival deformities.
MATERIALS AND METHODS
83 systematically healthy children were examined twice with an interval of 2 years. Probing depth, GT and AGW at mandibular incisors, vestibular depth, type of lower lip frenum attachment and mucogingival defects were recorded.
RESULTS
95.2% of participants at baseline and 93.9% at 2-year examination expressed thin GPh. During the transition from the deciduous to permanent dentition, GT and AGW declined, but the GT of permanent incisors already erupted at the baseline examination increased in the observation period.
CONCLUSIONS
Gingival phenotype undergoes changes in the early transitional dentition phase. In spite of the thin gingival phenotype, only single pseudo-recessions and primary shallow vestibule were noticed.
Topics: Dentition, Mixed; Gingiva; Humans; Incisor; Longitudinal Studies; Phenotype; Prevalence
PubMed: 35409581
DOI: 10.3390/ijerph19073899 -
Progress in Orthodontics Mar 2019Marfan syndrome is a rare autosomal dominant inherited disease of the connective tissue associated with various craniofacial abnormalities. Aim of the present study was...
BACKGROUND
Marfan syndrome is a rare autosomal dominant inherited disease of the connective tissue associated with various craniofacial abnormalities. Aim of the present study was to assess the variability of palatal shape in a sample of 31 Marfan patients compared to a control group of no syndromic subjects, in two stages of dentition, by using 3D geometric morphometric analysis.
METHODS
Thirty one growing subjects with Marfan syndrome were selected and divided into two subgroups: MG1 with mixed dentition (10 M, 6F, mean age 7+/- 0.7 years), MG2 with permanent dentition (8 M, 7F, mean age 13+/- 0,5 years). Each subgroup was compared to a control group (CG1 mixed dentition, 9 M, 7F, mean age 7.6+/- 0.5 years; CG2 permanent dentition, 9 M, 6F, mean age 12.8+/- 0.7 years) matched on age, sex distribution, stage of dentition and skeletal maturation. Then the two subgroups were compared one to each other. For each patient maxillary dental casts were taken, scanned and digitized. 3D geometric morphometric methods were applied. Procrustes analysis was used and principal component analysis was performed to reveal the main patterns of palatal shape variation.
RESULTS
Both Marfan subgroups showed important reductions in the transversal plane associated with a deep palatal vault when compared to the control groups (MG1 vs CG1 P = 0,003; MG2 vs CG2 P = 0,07). Moreover a statistically significant difference between the palatal shape of MG1 and MG2 was found (P = 0.017) showing a significant worsening of palatal depth and constriction from mixed to permanent dentition in Marfan subjects.
CONCLUSION
Marfan subjects showed a specific palatal morphology with maxillary constriction and deeper palatal vault when compared to a control group of healthy subjects. The constriction and the depth of the palatal vault in Marfan patients worsen from mixed dentition to permanent dentition more then in no syndromic subjects.
Topics: Adolescent; Child; Child, Preschool; Dentition; Dentition, Mixed; Dentition, Permanent; Humans; Marfan Syndrome; Maxilla; Palate
PubMed: 30880370
DOI: 10.1186/s40510-019-0264-2 -
The Journal of Clinical Pediatric... 2016To evaluate the prevalence and distribution of posterior crossbite in different dentition stages in a Turkish sample.
OBJECTIVE
To evaluate the prevalence and distribution of posterior crossbite in different dentition stages in a Turkish sample.
STUDY DESIGN
1554 subjects (843 girls, 711 boys) aged 4-25 years were evaluated to determine the prevalence of posterior crossbite in a Turkish sample. The subjects were classified according to four dentition stages (primary, early mixed, late mixed and permanent) and transversal occlusal status. The statistical evaluation was done by Chi-square, Fischer exact tests.
RESULTS
Bilateral and unilateral crossbite on the right and left sides had the highest frequency in the permanent dentition (51.0%, 47.3%, and 53.6%; respectively). No significant differences were found between unilateral (right and left) and bilateral crossbite with regard to dentition stages. No significant differences were found between unilateral right or left side posterior crossbite with regard to dentition stages.
CONCLUSION
An increasing trend in the prevalence of posterior crossbite was observed from the primary dentition towards permanent dentition in this study.
Topics: Adolescent; Adult; Child; Child, Preschool; Decision Making; Dentition, Mixed; Dentition, Permanent; Epidemiologic Studies; Female; Humans; Male; Malocclusion; Orthodontics, Corrective; Prevalence; Tooth, Deciduous; Turkey; Young Adult
PubMed: 27617385
DOI: 10.17796/1053-4628-40.5.422 -
The Journal of Clinical Pediatric... 2001The aim of this study was to investigate the relationship between occlusal factors (overjet, overbite, Angle's Classification of molars and cuspids, the relationship of... (Comparative Study)
Comparative Study
The aim of this study was to investigate the relationship between occlusal factors (overjet, overbite, Angle's Classification of molars and cuspids, the relationship of the primary molars, openbite, lateral openbite, scissorbite and crossbite) and bruxism in permanent and mixed dentition in Turkish children. For this reason 182 children with mixed dentition and 212 children with permanent dentition were included in this study. Occlusal conditions were examined clinically and bruxism was assessed by using interview and questionnaires. Z Test was used to compare the results. It was found that in both dentitions some occlusal factors related with bruxism (overjet > 6 mm, overbite > 5 mm, negative overjet, openbite in permanent dentition; overjet > 6 mm, overbite > 5 mm, scissorbite, anterior-posterior multiple teeth crossbite, Angle Class I occlusion in mixed dentition.
Topics: Adolescent; Bruxism; Child; Cuspid; Dentition, Mixed; Dentition, Permanent; Female; Humans; Incisor; Interviews as Topic; Male; Malocclusion; Molar; Statistics as Topic; Surveys and Questionnaires; Tooth, Deciduous; Turkey
PubMed: 12049076
DOI: 10.17796/jcpd.25.3.84m695q650622568