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Nederlands Tijdschrift Voor... Oct 2023The presence of subgingival pathology, such as a deep secondary caries lesion, a fracture, an already existing restoration that needs to be replaced or the presence of a... (Review)
Review
The presence of subgingival pathology, such as a deep secondary caries lesion, a fracture, an already existing restoration that needs to be replaced or the presence of a resorption defect, can constitute a difficult starting situation for the preservation of a tooth. How to deal with such a situation has been a topic of discussion for years. Surgical crown lengthening is one of the first and classic treatment options that is often chosen in such cases. Crown lengthening is a periodontal surgical technique to obtain extra supra crestal clinical crown length. The question is, what is the long-term prognosis of teeth after surgical crown lengthening. To answer this question, a review of the literature was carried out looking for clinical studies examining survival. Four studies with a follow-up of at least 5 years were included. The factors that adversely affect survival of the tooth after the crown lengthening are an unfavourable crown-root ratio, insufficient plaque control and moderate ability to keep the restoration clean.
Topics: Humans; Crown Lengthening; Tooth Fractures; Tooth Crown; Crowns; Dental Caries
PubMed: 37814836
DOI: 10.5177/ntvt.2023.10.23052 -
Nederlands Tijdschrift Voor... May 2001Trauma to the teeth can result in the formation of cracks in the crown or root of the tooth. The location and the extent of these cracks determine the proper treatment... (Review)
Review
Trauma to the teeth can result in the formation of cracks in the crown or root of the tooth. The location and the extent of these cracks determine the proper treatment choice. This treatment is oriented towards saving pulp vitality and/or tooth integrity. In this paper the diagnosis of these cracks is described as well as the desired treatment. These are discussed relative to the location of the cracks, namely in the clinical crown of the tooth, resulting in enamel infraction, cracked tooth and crown fractures, and in the root of the tooth, resulting in a vertical or horizontal root fracture.
Topics: Dental Restoration, Permanent; Humans; Radiography; Tooth Crown; Tooth Fractures; Tooth Root
PubMed: 11400591
DOI: No ID Found -
International Journal of Computer... Aug 2023The design of a maxillary anterior tooth crown is crucial to post-treatment aesthetic appearance. Currently, the design is performed manually or by semi-automatic...
PURPOSE
The design of a maxillary anterior tooth crown is crucial to post-treatment aesthetic appearance. Currently, the design is performed manually or by semi-automatic methods, both of which are time-consuming. As such, automatic methods could improve efficiency, but existing automatic methods ignore the relationships among crowns and are primarily used for occlusal surface reconstruction. In this study, the authors propose a novel method for automatically reconstructing a three-dimensional model of the maxillary anterior tooth crown.
METHOD
A pose estimation network (PEN) and a shape estimation network (SEN) are developed for jointly estimating the crown point cloud. PEN is a regression network used for estimating the crown pose, and SEN is based on an encoder-decoder architecture and used for estimating the initial crown point cloud. First, SEN adopts a transformer encoder to calculate the shape relationship among crowns to ensure that the shape of the reconstructed point cloud is precise. Second, the initial point cloud is subjected to pose transformation according to the estimated pose. Finally, the iterative method is used to form the crown mesh model based on the point cloud.
RESULT
The proposed method is evaluated on a dataset with 600 cases. Both SEN and PEN are converged within 1000 epochs. The average deviation between the reconstructed point cloud and the ground truth of the point cloud is 0.22 mm. The average deviation between the reconstructed crown mesh model and the ground truth of the crown model is 0.13 mm.
CONCLUSION
The results show that the proposed method can automatically and accurately reconstruct the three-dimensional model of the missing maxillary anterior tooth crown, which indicates the method has promising application prospects. Furthermore, the reconstruction time takes less than 11 s for one case, demonstrating improved work efficiency.
Topics: Humans; Imaging, Three-Dimensional; Tooth Crown; Tooth; Crowns; Maxilla
PubMed: 36754949
DOI: 10.1007/s11548-023-02841-1 -
The Journal of Forensic... May 2019The aim of this study was to determine whether the tooth crown sexual dimorphism pattern reported in previous small studies can be generalized for a broader range of... (Meta-Analysis)
Meta-Analysis
OBJECTIVE
The aim of this study was to determine whether the tooth crown sexual dimorphism pattern reported in previous small studies can be generalized for a broader range of populations.
LITERATURE REVIEW
A systematic literature review was performed by two independent examiners. The following databases were searched from October 2015 to July 2016: PubMed, Scopus, Lilacs, ScienceDirect, Medline, and Cochrane Reviews. No language restrictions were applied to the search.
SELECTION CRITERIA
The inclusion criteria comprised original studies investigating mesiodistal permanent teeth that reported the sample population and standard deviation. All right-sided teeth, except the third molars, were measured and separated by sex in the included studies. Thirty-one studies were included in the quantitative data synthesis and meta-analysis. Studies of non-human teeth, skeletal remains, or an overly specific study population were excluded.
MAIN RESULTS
Thirty-one trials, involving 6481 participants, provided data for the meta-analysis of teeth. Sexual dimorphism in mesiodistal crowns was found in all teeth across a range of populations, principally in lower canines (5.73%) and maxillary canines (4.72%), followed by the lower second molars (3.54%) and upper second molars(3.20%), and finally in the lower first molars(3.14%) and upper first molars(2.64%).
CONCLUSIONS
A small degree of sexual dimorphism exists in all human teeth. Second molars and canines show the greatest sexual dimorphism. Additionally, smaller racial differences are present in mesiodistal crowns among groups living in different geographic areas; however, it is not possible to establish a single value applicable for all populations.
Topics: Humans; Odontometry; Sex Characteristics; Tooth Crown
PubMed: 31187738
DOI: No ID Found -
American Journal of Physical... Sep 1997The defects of enamel hypoplasia can be related to the layered structure of enamel which represents the sequence of development in tooth crowns. From such studies, it is... (Review)
Review
The defects of enamel hypoplasia can be related to the layered structure of enamel which represents the sequence of development in tooth crowns. From such studies, it is possible to see that furrow-type enamel defects (the most common form of hypoplasia seen with the naked eye) are just the most prominent expression of a continuum which extends ever smaller, down to a microscopic disturbance to a single layer in the crown formation sequence. Furthermore, the progressive decrease in spacing between development layers which occurs down the crown sides, from occlusal to cervical, affects both the prominence and apparent width of the defects. This makes it difficult to use measurements as a means of estimating the duration of the disturbance causing a particular defect. The difficulty is even greater for the less common pitted or exposed-plane-type defects, for which the apparent width bears very little relationship with the duration of the growth disturbance. The defects of enamel hypoplasia can therefore be understood clearly only when examined under the microscope in relation to the structures which mark the development sequence of the tooth crown.
Topics: Anthropometry; Dental Enamel Hypoplasia; Humans; Tooth Crown
PubMed: 9331455
DOI: 10.1002/(SICI)1096-8644(199709)104:1<89::AID-AJPA6>3.0.CO;2-8 -
Journal of Forensic Sciences Jul 2022Odontometrics, also known as metric traits, includes mesiodistal, buccolingual dimensions, and crown height. The purpose of this study was to assess pancontinental... (Meta-Analysis)
Meta-Analysis Review
Odontometrics, also known as metric traits, includes mesiodistal, buccolingual dimensions, and crown height. The purpose of this study was to assess pancontinental odontometric variations in the crown dimensions of primary teeth. Ten electronic databases were searched to identify studies that measured crown dimensions of primary teeth, published in English language, without year restriction up to July 2020. Studies included cross-sectional research measuring on casts, subjects, and on radiographs of healthy children. Meta-analysis was performed, and risk of bias was assessed using modified Newcastle-Ottawa Scale. Eighty-seven observational studies were included, with 24,634 participants (9487 males, 11,083 females; 19 studies lacked gender information). Only one study showed a low bias risk, whereas 81 and 5 studies had moderate and high risk, respectively. Sixty-five studies included for meta-analysis revealed heterogeneity in mean mesiodistal dimensions of maxillary first molars from Asia (I -99.7%), buccolingual measurements of mandibular first molars from Europe (I -99.9%), crown height of mandibular second molars from Africa and Europe (I -79.8%). Among mesiodistal and buccolingual dimensions, Australians have larger while Asians have smaller teeth. Pertaining to crown height, very few studies could be found in the literature. This review highlights the variations in crown dimensions of primary teeth among populations.
Topics: Australia; Child; Cross-Sectional Studies; Female; Humans; Male; Molar; Odontometry; Tooth Crown; Tooth, Deciduous
PubMed: 35246979
DOI: 10.1111/1556-4029.15015 -
Anatomical Record (Hoboken, N.J. : 2007) Dec 2020Tooth developmental stage evaluation is important in dental and chronological age estimation, and it is important for accurate diagnoses and appropriate treatment in...
Tooth developmental stage evaluation is important in dental and chronological age estimation, and it is important for accurate diagnoses and appropriate treatment in dental practice. It is routinely assessed by clinical observations and radiographic techniques. This study aimed at ascertaining tooth developmental stage judgments made by examiners and Mimics software according to the Nolla method with radiographs. Meanwhile, the true tooth developmental stages would be explored with histological analysis. Twenty freshly slaughtered porcine heads were collected and hemisected, and both the left and right mandibular samples were numbered. The developmental stages of the second and third permanent molars (M2 and M3) were evaluated by examiners and Mimics software analysis. The ratio of the radiopaque calcified area to the dental follicle (RCA/DF) at different stages was calculated. Both non-decalcified and decalcified samples were processed for histologic observation. The results showed significant differences between RCA/DF ratios from different developmental stages. There was a high positive correlation between the examiners' evaluation results and Mimics analysis results. Radiograph judgments and histology observation results were consistent from Stages 2-6. However, radiograph images of Stage 1 samples showed only crypts present, while under a surgical operating microscope, a bell-shaped tooth germ was observed. This was also confirmed by normal and hard tissue histology. In conclusion, radiograph judgments made by either examiners or Mimics software were both reliable. Mimics analysis can be a useful tool in evaluating tooth developmental stages. However, judgments need to be made cautiously in early developmental stages.
Topics: Animals; Image Processing, Computer-Assisted; Mandible; Odontogenesis; Swine; Tomography, X-Ray Computed; Tooth; Tooth Crown
PubMed: 31930691
DOI: 10.1002/ar.24366 -
Journal of Experimental Zoology. Part... Jul 2009Considering tooth crown engineering, three main parameters have to be taken into account: (1) the relationship between crown morphology and tooth functionality, (2) the...
Considering tooth crown engineering, three main parameters have to be taken into account: (1) the relationship between crown morphology and tooth functionality, (2) the growth of the organ, which is hardly compatible with the use of preformed scaffolds, and (3) the need for easily available nondental competent cell sources. In vitro reassociation experiments using either dental tissues or bone marrow-derived cells (BMDC) have been designed to get information about the mechanisms to be preserved in order to allow crown engineering. As the primary enamel knot (PEK) is involved in signaling crown morphogenesis, the formation and fate of this structure was investigated (1) in heterotopic reassociations between embryonic day 14 (ED14) incisor and molar enamel organs and mesenchymes, and (2) in reassociations between ED14 molar enamel organs and BMDC. A PEK formed in cultured heterotopic dental tissue reassociations. The mesenchyme controls the fate of the EK cells, incisor or molar-specific using apoptosis as criterion, and functionality to drive single/multiple cusps tooth development. Although previous investigations showed that they might differentiate as odontoblast- or ameloblast-like cells, BMDC reassociated to an enamel organ could not support the development of multicusp teeth. These cells apparently could neither maintain nor stimulate the formation of a PEK.
Topics: Animals; Bone Marrow Cells; Dental Enamel; Epithelial Cells; Female; Femur; Incisor; Mice; Mice, Inbred ICR; Molar; Tibia; Tissue Engineering; Tooth; Tooth Crown
PubMed: 19132735
DOI: 10.1002/jez.b.21256 -
Nigerian Journal of Clinical Practice May 2020The aim of this retrospective study is to evaluate and compare the 3-dimensional (3D) crown sizes of the left and right sides of upper and lower dental arches in...
AIM
The aim of this retrospective study is to evaluate and compare the 3-dimensional (3D) crown sizes of the left and right sides of upper and lower dental arches in patients with unilateral cleft lip and palate (UCLP).
MATERIALS AND METHODS
Dental casts of 94 patients all in permanent dentition were included in this study. Dental casts were divided into three groups as 36 casts with unilateral left cleft lip and palate (ULCLP), 18 casts with unilateral right cleft lip and palate (URCLP), and 40 casts without cleft (control). Mesiodistal (MD), buccolingual (BL), and gingiva incisal (GI) values of each tooth were measured by scanning the dental models with a high-precision optical 3D scanner. Paired t-test and independent t-test were used for statistical analysis.
RESULTS
U1 MD, U6 MD (P = 0.001) and BL (P = 0.01), L3 GI (P = 0.05) were greater in UCLP patients on the non-cleft side while U1 GI, L1 BL, L5 MD (P = 0.001), L4 MD, and BL (P = 0.01) values were found to be greater on the cleft side. Comparison of the cleft-sides and the control group showed that MD, BL, and GI dimensions of teeth on the cleft sides were generally found to be smaller, excluding the UR7 GI values for URCLP group (P = 0.05).
CONCLUSION
In the measurements of teeth size, reliable and repeatable results were acquired through 3D software. Tooth size asymmetries can occur non-syndromic UCLP patients in both jaws. MD, BL, and GI dimensions of teeth are mostly found to be smaller in patients with CLP.
Topics: Case-Control Studies; Child; Cleft Lip; Cleft Palate; Dental Occlusion; Female; Humans; Image Processing, Computer-Assisted; Imaging, Three-Dimensional; Male; Maxilla; Odontometry; Retrospective Studies; Tooth Crown
PubMed: 32367864
DOI: 10.4103/njcp.njcp_537_19 -
British Dental Journal Mar 2020
Topics: Incisor; Tooth Crown
PubMed: 32221422
DOI: 10.1038/s41415-020-1441-x