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International Journal of Environmental... Jul 2022Eruption is a complex and dynamic process determined by both genetic and epigenetic factors. This process involves a number of changes in the tissues surrounding the...
Eruption is a complex and dynamic process determined by both genetic and epigenetic factors. This process involves a number of changes in the tissues surrounding the tooth and in tooth morphology. The aim of this study was to analyze the eruption sequence of permanent canines and premolars on the basis of pantomographic images. The study material consisted of 300 digital pantomographic images of children in the developmental period. The study group consisted of 165 boys and 135 girls. Images of patients of Polish nationality, aged 6-10 years, without diagnosed systemic diseases and local disorders were used in the study. Results: The study has shown that the most common pattern of tooth eruption in the lateral zones is type A positioning of the lateral teeth, which is 4-5-3. This pattern is characteristic of both girls and boys. This pattern also occurs most frequently in the maxilla in both boys and girls. In the mandible, on the contrary, two patterns of lateral tooth eruption were predominant. In girls, types A and E/4-5-3 and 3-4-5/occurred in the mandible, while in boys, types A and C/4-5-3 and 5-4-3/were observed in the mandible. The process of tooth eruption is a recognized measure of a child's physical development, and pantomographic images are an effective and common diagnostic tool.
Topics: Age Factors; Bicuspid; Cuspid; Humans; Poland; Tooth Eruption
PubMed: 35886323
DOI: 10.3390/ijerph19148464 -
Progress in Orthodontics Mar 2022To evaluate the correspondence between the interproximal reduction (IPR) performed clinically and that programmed in ClinCheck® and further assess which teeth showed an...
AIM
To evaluate the correspondence between the interproximal reduction (IPR) performed clinically and that programmed in ClinCheck® and further assess which teeth showed an amount of implemented IPR (I-IPR) that corresponds with that programmed in ClinCheck®.
MATERIALS AND METHODS
Pre- (T0) and post-treatment (T1) ClinCheck® digital models for 75 subjects (30 males and 45 females), mean age (38 ± 15) years, were included. To calculate the amount of I-IPR, Ortho Analyzer software (3Shape, Copenhagen, Denmark) was used to measure the mesiodistal widths for the maxillary and mandibular teeth from second premolar to the contralateral second premolar on the initial (T0) and final (T1) STL models. I- IPR performed by tooth was obtained by comparing the mesiodistal width of each tooth at T0 and T1. The amount of programmed IPR (P-IPR) in ClinCheck® was compared to that implemented clinically using the following formula: IPR difference = (P-IPR) - (I-IPR).
RESULTS
Statistically significant differences were observed between the average value of digitally programmed and implemented IPR per tooth for both the maxillary (p < .0001) and mandibular (p < .0001) teeth. The mean P-IPR for the maxillary teeth was 0.28 ± 0.16 mm versus the mean I-IPR of 0.15 ± 0.15 mm. In the mandibular arch, the mean P-IPR was 0.31 ± 0.17 mm, while the I-IPR was 0.17 ± 0.16 mm. The mean I-IPR was consistently lower than the mean P-IPR regardless of teeth and sites (p < 0.0001). The difference between the P-IPR compared to the I-IPR was larger for mandibular anterior teeth than for maxillary anterior teeth (p = 0.0302) and larger for maxillary posterior teeth than mandibular posterior teeth (p = 0.0059).
CONCLUSION
The amount of implemented-IPR in clear aligner therapy is less than that digitally programmed for most teeth. Regardless of the regions, I-IPR was consistently lower than that programmed. Mandibular anterior teeth and maxillary posterior teeth showed greater discrepancy between P-IPR and I-IPR than the maxillary anterior and mandibular posteriors. Further prospective studies are needed to determine the factors affecting the precision of IPR and the clinical implications of a significantly reduced I-IPR on treatment outcomes.
Topics: Adult; Bicuspid; Female; Humans; Male; Mandible; Maxilla; Middle Aged; Orthodontic Appliances, Removable; Tooth Movement Techniques; Young Adult
PubMed: 35254555
DOI: 10.1186/s40510-022-00403-w -
The Angle Orthodontist Jul 2020
Topics: Bicuspid; Cephalometry; Humans
PubMed: 32591799
DOI: 10.2319/0003-3219-90.4.619 -
PloS One 2021Human root and canal number and morphology are highly variable, and internal root canal form and count does not necessarily co-vary directly with external morphology....
Human root and canal number and morphology are highly variable, and internal root canal form and count does not necessarily co-vary directly with external morphology. While several typologies and classifications have been developed to address individual components of teeth, there is a need for a comprehensive system, that captures internal and external root features across all teeth. Using CT scans, the external and internal root morphologies of a global sample of humans are analysed (n = 945). From this analysis a method of classification that captures external and internal root morphology in a way that is intuitive, reproducible, and defines the human phenotypic set is developed. Results provide a robust definition of modern human tooth root phenotypic diversity. The method is modular in nature, allowing for incorporation of past and future classification systems. Additionally, it provides a basis for analysing hominin root morphology in evolutionary, ecological, genetic, and developmental contexts.
Topics: Bicuspid; Humans; Phenotype; Tomography, X-Ray Computed; Tooth Root
PubMed: 34739489
DOI: 10.1371/journal.pone.0251953 -
Scientific Reports Oct 2022This study investigates fracture resistance of adhesive ceramic overlays of various designs. Forty-eight upper premolar teeth were divided into eight groups. The...
This study investigates fracture resistance of adhesive ceramic overlays of various designs. Forty-eight upper premolar teeth were divided into eight groups. The variations were: shoulder margins on the buccal and lingual surfaces with axial wall heights of 1, 2, or 3 mm; one shoulder margin with axial wall height of 1, 2, or 3 mm on the lingual surface and one contrabevel margin on the buccal surface; contrabevel margins on the buccal and lingual surfaces; and a control of sound teeth. Overlays were designed and fabricated with CAD/CAM using zirconia-reinforced lithium disilicate ceramic and bonded with resin cement. Samples underwent thermocycling and dynamic fatigue equivalent to 6 months of use. Compressive loading was applied until fracture, and fracture mode was analyzed. Results showed no statistical difference in fracture resistance between designs, and the fracture pattern of most was involvement of pulp tissue and below the CEJ. Fracture resistance of the restored teeth was also not statistically different from the control. All control fractures were within the dentin and above the CEJ. Overlay restorations were therefore effective in strengthening damaged teeth and imparting fracture resistance equal to sound teeth, and axial wall heights and margin types did not influence this result.
Topics: Bicuspid; Ceramics; Computer-Aided Design; Materials Testing; Resin Cements
PubMed: 36198863
DOI: 10.1038/s41598-022-21167-7 -
Scientific Reports Jul 2021This study aimed to assess the viability of dental cells following time-dependent carbamide peroxide teeth-whitening treatments using an in-vitro dentin perfusion assay...
This study aimed to assess the viability of dental cells following time-dependent carbamide peroxide teeth-whitening treatments using an in-vitro dentin perfusion assay model. 30 teeth were exposed to 5% or 16% CP gel (4 h daily) for 2-weeks. The enamel organic content was measured with thermogravimetry. The time-dependent viability of human dental pulp stem cells (HDPSCs) and gingival fibroblast cells (HGFCs) following either indirect exposure to 3 commercially available concentrations of CP gel using an in-vitro dentin perfusion assay or direct exposure to 5% HO were investigated by evaluating change in cell morphology and by hemocytometry. The 5% and 16% CP produced a significantly lower (p < 0.001) enamel protein content (by weight) when compared to the control. The organic content in enamel varied accordingly to the CP treatment: for the 16% and 5% CP treatment groups, a variation of 4.0% and 5.4%, respectively, was observed with no significant difference. The cell viability of HDPSCs decreased exponentially over time for all groups. Within the limitation of this in-vitro study, we conclude that even low concentrations of HO and CP result in a deleterious change in enamel protein content and compromise the viability of HGFCs and HDPSCs. These effects should be observed in-vivo.
Topics: Bicuspid; Carbamide Peroxide; Cell Survival; Cells, Cultured; Dental Enamel; Dental Pulp; Dentin; Humans; Hydrogen Peroxide; Molar; Tooth Bleaching Agents
PubMed: 34330953
DOI: 10.1038/s41598-021-94745-w -
PloS One 2024Morphological variation in modern human dentition is still an open field of study. The understanding of dental shape and metrics is relevant for the advancement of human...
Morphological variation in modern human dentition is still an open field of study. The understanding of dental shape and metrics is relevant for the advancement of human biology and evolution and is thus of interest in the fields of dental anthropology, as well as human anatomy and medicine. Of concern is also the variation of the inner aspects of the crown which can be investigated using the tools and methods of virtual anthropology. In this study, we explored inter- and intra-population morphometric variation of modern humans' upper third and fourth premolars (P3s and P4s, respectively) considering both the inner and outer aspects of the crown, and discrete traits. We worked by means of geometric morphometrics on 3D image data from a geographically balanced sample of human populations from five continents, to analyse the shape of the dentinal crown, and the crown outline in 78 P3s and 76 P4s from 85 individuals. For the study of dental traits, we referred to the Arizona State University Dental Anthropology System integrated with more recent classification systems. The 3D shape variation of upper premolar crowns varied between short and mesio-distally broad, and tall and mesio-distally narrow. The observed shape variation was independent from the geographical origin of the populations, and resulted in extensive overlap. We noted a high pairwise correlation (r1 = 0.83) between upper P3s and P4s. We did not find any significant geographic differences in the analysed non-metric traits. Our outcomes thus suggest that geographical provenance does not play a determinant role in the shaping of the dental crown, whose genesis is under strict genetic control.
Topics: Animals; Humans; Bicuspid; Anthropology, Physical; Hominidae; Anthropology; Tooth Crown
PubMed: 38593117
DOI: 10.1371/journal.pone.0301482 -
Journal of the American College of... Apr 2016
Topics: Aortic Valve; Aortic Valve Stenosis; Bicuspid; Heart Valve Diseases; Humans
PubMed: 27081019
DOI: 10.1016/j.jacc.2016.02.038 -
The Angle Orthodontist Nov 2008To use published data to evaluate quantitatively the dental effects of noncompliance intramaxillary appliances in individuals with Class II malocclusion. (Review)
Review
OBJECTIVE
To use published data to evaluate quantitatively the dental effects of noncompliance intramaxillary appliances in individuals with Class II malocclusion.
MATERIALS AND METHODS
A literature search was carried out identifing 13 prospective or retrospective clinical studies matching inclusion criteria. Only appliances with conventional anchorage designs were considered for the review. The data provided in these publications were grouped and analyzed in terms of molar distalization, tipping and vertical movements, and incisor and premolar mesialization, tipping, and vertical movements.
RESULTS
Maxillary first molars showed distal crown movement and tipping greater than the mesial crown movement and tipping shown by incisors and premolars. Vertical movements of incisors and premolars were in general extrusive, but molars were intrusive or extrusive, depending on the study and the type of appliance used. Appliances that acted palatally seemed to display a smaller distal tipping movement, as well as smaller incisor and premolar mesial tipping movements, when compared with those that acted buccally. Friction-free appliances, namely the pendulum, produced a large amount of mesiodistal movement and tipping, if no therapeutic uprighting activation was applied.
CONCLUSIONS
Noncompliance intramaxillary molar distalization appliances all act by distalizing molars with a concomitant and unavoidable loss of anchorage, as revealed by incisor and premolar mesial movement. Buccal acting and palatal acting appliances demonstrate almost similar results, with palatal acting appliances showing less tipping. Friction-free palatal acting appliances appear to produce better molar distalizing effects, but with a concomitant notable loss of anchorage.
Topics: Bicuspid; Humans; Incisor; Malocclusion, Angle Class II; Maxilla; Molar; Orthodontic Appliance Design; Orthodontic Appliances; Prospective Studies; Retrospective Studies; Tooth Movement Techniques
PubMed: 18947282
DOI: 10.2319/101507-406.1 -
Journal of Anatomy Nov 2005Normal and abnormal jaw growth and tooth eruption are topics of great importance for several dental and medical disciplines. Thus far, clinical studies on these topics... (Review)
Review
Normal and abnormal jaw growth and tooth eruption are topics of great importance for several dental and medical disciplines. Thus far, clinical studies on these topics have used two-dimensional (2D) radiographic techniques. The purpose of the present study was to analyse normal mandibular growth and tooth eruption in three dimensions based on computer tomography (CT) scans, extending the principles of mandibular growth analysis proposed by Björk in 1969 from two to three dimensions. As longitudinal CT data from normal children are not available (for ethical reasons), CT data from children with Apert syndrome were employed, because it has been shown that the mandible in Apert syndrome is unaffected by the malformation, and these children often have several craniofacial CT scans performed during childhood for planning of cranial and midface surgery and for follow-up after surgery. A total of 49 datasets from ten children with Apert syndrome were available for study. The number of datasets from each individual ranged from three to seven. The first CT scan in each of the ten series was carried out before 1 year of age, and the ages for the 49 scans ranged from 1 week to 14.5 years. The mandible and the teeth were segmented and iso-surfaces generated. Landmarks were placed on the surface of the mandible, along the mandibular canals, the inner contour of the cortical plate at the lower border of the symphysis menti, and on the teeth. Superimposition of the mandibles in the longitudinal series was performed using the symphysis menti and the mandibular canals as suggested by Björk. The study supported the findings of stability of the symphysis menti and the mandibular canals as seen in profile view previously reported by Björk & Skieller in 1983. However, the mandibular canals were, actually, relocated laterally during growth. Furthermore, the position of tooth buds remained relatively stable inside the jaw until root formation started. Eruption paths of canines and premolars were vertical, whereas molars erupted in a lingual direction. The 3D method would seem to offer new insight into jaw growth and tooth eruption, but further studies are needed.
Topics: Acrocephalosyndactylia; Adolescent; Bicuspid; Child; Child, Preschool; Cuspid; Female; Humans; Imaging, Three-Dimensional; Infant; Longitudinal Studies; Male; Mandible; Molar; Tomography, X-Ray Computed; Tooth Eruption
PubMed: 16313399
DOI: 10.1111/j.1469-7580.2005.00479.x