Vestibular Lamina Research Articles

Prenatal and postnatal development of New Zealand white rabbit (Oryctolagus cuniculus) teeth: histological and computed tomography aspects

The study reveals a lack of histomorphogenesis in New Zealand white rabbit teeth. The teeth development was examined through sequential histological segments in 24 rabbits from prenatal ages (E19, E21, E23, E25, and E28), neonates (E30), and postnatal age (1 week and 2 weeks); (three animal specimens at each age stage). Rabbit teeth first appeared at 19 days of prenatal life (E19) as an ectodermal epithelial thickening on each side of the mouth opening. At E21, the bud of upper incisor tooth appeared as an epithelial bud, which composed of many condensed epithelium cells, was simply identified from the larger with less condensed vestibular lamina, and was surrounded by mesenchymal connective tissue while the lower incisor took the cap stage. At (E23), tooth regular construction is formed from enamel, dentine, and pulp cavity. Peg incisor appearance (supplementary and assistant incisors) is visible at the lingual surface of the upper major incisor. Teeth prenatal development went through successive stages like initiation, bud, cap, late bell, maturation, and crown stages. The first initiation phase of tooth formation was seen as ectodermal epithelial cell collection at (E19). Bud stage saw on upper incisor tooth, while in cap structure in lower incisor teeth at (E19). A cap-formed tooth is composed of the enamel organ and fundamentally dense mesenchymal tissue. Enamel organs are segmented into three distinct layers: the external tooth enamel epithelial, the internal tooth enamel epithelial, and finally the stellate reticular layer. The cement layer covered teeth all around on enamel on both the labial and lingual sides while not contacting the dentine on the lateral side, forming enamel space. Teeth develop consistently all through life; they have expanded enamel thickness; they are diphyodont teeth; they have two continuous dentitions; they are deciduous and perpetual, with long crown teeth and an open root.

(090) Immunohistochemical Staining of Elastin in the Vestibule

Abstract Introduction The vestibule is an external genital structure lying 90° to the vaginal canal opening. During the thrusting movements associated with penetrative sexual activity, the vestibule undergoes significant stretching during both invagination and evagination. The vestibule also undergoes extreme stretching during childbirth. The rete pegs in the non-keratinized squamous epithelium facilitate the ability of the vestibule to mechanically stretch. More importantly, however, the vestibular lamina propria, with nerves, blood vessels, glands, needs to contain a high density of extracellular matrix (ECM) proteins with stretching capabilities. In particular, the ECM protein elastin endows skin structures with the ability to stretch, recoil, and have elasticity. Elastin has previously been shown to influence mechanical stretching properties of tendons. Objective The objective of this study was to examine the density of elastin proteins in the vestibule in reproductive age patients as there are currently limited data. Methods A total of 7 reproductive age patients with normal sex steroid hormone values and complaints of entrance dyspareunia were diagnosed with neuroproliferative vestibulodynia and subsequently underwent complete vestibulectomy. Tissue blocks were created from the specimen, and 5 μm sections studied with immunohistochemical staining with primary antibody. Sections were then counterstained with Gill-modified hematoxylin. Results In all vestibular specimen, there was very high density of elastin underneath the epithelium in rete pegs and throughout the entire lamina propria (Fig 1). There is a density gradient with the highest density immediately deep to the basement membrane of the epithelium. Elastin fibers were arranged in all orientations: coronal (frontal), sagittal (longitudinal), and transverse (axial) planes. Conclusions The high density of elastin fibers in rete pegs and throughout the lamina propria in a multi-planar orientation is suggestive of extreme stretching capability in eugonadal vestibular tissues. The highest density of elastin staining was seen immediately below the basement membrane of the epithelium, which may provide tissue integrity and shear resilience to the epithelial layer. In sex steroid hormone insufficiency states such as menopause or with use of combined hormonal contraceptives, individuals may develop loss of introital elasticity and fissures due to a deficiency of the ECM protein elastin. More research is needed on elastic fiber production, organization, and integration with other cutaneous extracellular matrix proteins, and how they may be affected by sex steroid hormones. Disclosure Any of the authors act as a consultant, employee or shareholder of an industry for: Endoceutics, Inc.

Molecular profiling of the vestibular lamina highlights a key role for Hedgehog signalling.

The vestibular lamina (VL) forms the oral vestibule, creating a gap between the teeth, lips and cheeks. In a number of ciliopathies, formation of the vestibule is defective, leading to the creation of multiple frenula. In contrast to the neighbouring dental lamina, which forms the teeth, little is known about the genes that pattern the VL. Here, we establish a molecular signature for the usually non-odontogenic VL in mice and highlight several genes and signalling pathways that may play a role in its development. For one of these, the Sonic hedgehog (Shh) pathway, we show that co-receptors Gas1, Cdon and Boc are highly expressed in the VL and act to enhance the Shh signal from the forming incisor region. In Gas1 mutant mice, expression of Gli1 was disrupted and the VL epithelium failed to extend due to a loss of proliferation. This defect was exacerbated in Boc/Gas1 double mutants and could be phenocopied using cyclopamine in culture. Signals from the forming teeth, therefore, control development of the VL, coordinating the development of the dentition and the oral cavity.

Mechanisms driving vestibular lamina formation and opening in the mouse.

The vestibular lamina (VL) forms as an epithelial outgrowth parallel to the dental lamina (DL) in the oral cavity. During late development, it opens to create a furrow that divides the dental tissue from the cheeks and lips and is known as the vestibule. Defects in this process lead to failurein the separation of the teeth from the lips and cheeks, including the presence of multiple frenula. In this paper, the development of the VL is followed in the mouse, from epithelial placode in the embryo to postnatal opening and vestibule formation. During early outgrowth, differential proliferation controls the curvature of the VL as it extends under the forming incisors. Apoptosis plays a role in thinning the deepest part of the lamina, while terminal differentiation of the epithelium, highlighted by the expression of loricrin and flattening of the nuclei, predates the division of the VL into two to create the vestibule. Development in the mouse is compared to the human VL, with respect to the relationship of the VL to the DL, VL morphology and mechanisms of opening. Overall, this paper provides insight into an understudied part of the oral anatomy, shedding light on how defects could form in this region.

Prevalence of type of maxillary labial frenal attachment among 18-30 years: A retrospective study

The frenum has its origin from the remnant of central cells of vestibular lamina which predominantly has connective tissue and least amount of muscle fibers. Labial frenum is a vertical band of oral mucosa that attaches the cheeks and lips to the alveolar mucosa of the mandibular and maxillary arches, limiting the movement of the lips and cheeks. The aim of the study was to find out the prevalence of the type of maxillary labial frenal attachment among 18-30 years. The present retrospective study was conducted among 100 outpatients who reported to a private institution in Chennai from June 2019 to March 2020. Data regarding the type of frenal attachment was collected and analysed. From our current study, it was found out that out of 100 patients, 41% had a gingival type, 27% had a mucosal and papillary type, 5% had the papillary penetrating type of maxillary labial frenal attachment and there was no significant association between gender and type of frenal attachment (Pearson Chi-Square test - 1.105, df-3, p value - 0.776(>0.05); statistically not significant). Within the limitations of the present study, the most prevalent type of maxillary frenal attachment in the given population was a gingival type. Least prevalent type was papillary penetrating and there was no significant association between gender and type of frenal attachment.

Development of the Vestibular Lamina in Human Embryos: Morphogenesis and Vestibule Formation.

The vestibular lamina (VL) is a transient developmental structure that forms the lip furrow, creating a gap between the lips/cheeks and teeth (oral vestibule). Surprisingly, little is known about the development of the VL and its relationship to the adjacent dental lamina (DL), which forms the teeth. In some congenital disorders, such as Ellis-van Creveld (EVC) syndrome, development of the VL is disrupted and multiple supernumerary frenula form, physically linking the lips and teeth. Here, we assess the normal development of the VL in human embryos from 6.5 (CS19) to 13 weeks of development, showing the close relationship between the VL and DL, from initiation to differentiation. In the anterior lower region, the two structures arise from the same epithelial thickening. The VL then undergoes complex morphogenetic changes during development, forming a branched structure that separates to create the vestibule. Changing expression of keratins highlight the differentiation patterns in the VL, with fissure formation linked to the onset of filaggrin. Apoptosis is involved in removal of the central portion of the VL to create a broad furrow between the future cheek and gum. This research forms an essential base to further explore developmental defects in this part of the oral cavity.

Przegląd wybranych atraumatycznych metod ekstrakcji

Tooth extraction is one of the most common dental surgical procedures. Its success depends on the operator’s knowledge, skills and experience. Proper choice of tools is also important. Incorrect tooth extraction using excessive force may cause local complications, such as damage to the soft tissue or to the extracted or neighbouring tooth with potential translocation, bone fracture, formation of an oral sinus communication or even mandibular dislocation. Currently, efforts are being made to develop methods that will allow for the preservation of intact surrounding periodontal tissues to facilitate subsequent prosthetic rehabilitation. Surgical tools used in atraumatic tooth extraction include, among other things, Physics Forceps, periotomes, luxators, and the Benex extractor system. These tools reduce the risk of damage to the vestibular lamina of the alveolar bone, allow for avoiding the need for a mucoperiosteal flap and reduce the incidence of postoperative pain. This helps create optimal conditions for subsequent implant prosthetic reconstruction. The paper presents the characteristics and application of selected tools used in atraumatic tooth extraction.

Early development of the human dentition revisited.

In this review, classical data on the early steps in human odontogenesis are summarized and updated with specific insights into the development of the upper and lower embryonic jaws to help in understanding some oral pathologies. The initial step of human odontogenesis is classically characterized by two parallel horseshoe‐shaped epithelial laminae. These originate from the oral epithelium and an ingrowth into the jaw mesenchyme: the internal dental lamina gives rise to deciduous tooth primordia, while the external vestibular lamina represents the developmental base of the oral vestibule. However, a more complex situation was revealed by recent studies combining analyses of the dental and adjacent oral epithelia on histological sections and computer‐aided three‐dimensional (3D) reconstructions during the 2nd month of human embryonic development. The dental epithelium forms a mound, where swellings appear later, corresponding to the individual primordia of deciduous teeth. External to the developing deciduous dentition, the 3D reconstructions do not show any continuous vestibular lamina but instead a complex of discontinuous epithelial bulges and ridges. The patterns of these epithelial structures and their relationship to the dental epithelium differ not only between the upper and lower jaws but also between the lip and cheek segments in each jaw. Knowledge of early odontogenesis may help in understanding some oral pathologies. For example, the human lateral incisor has a dual origin: it arises in the area of fusion between the medial nasal and maxillary facial processes and involves material from these two regions. Such a dual origin at the site of fusion of facial processes represents a predisposition to developmental vulnerability for the upper lateral incisor, resulting in its frequent anomalies (absence, hypoplasia, duplication), especially in patients with a cleft lip and/or jaw. Other pathologies, such as a minute supernumerary tooth, desmoplastic ameloblastoma or extraosseous odontogenic cysts are located external to the upper or lower dentition, and might be derived from structures that transiently appear during early development of the oral vestibule in humans.

The Influence of Specific Growth Factors on the Jaw Development in Anodontia Patients ‐ Porcine Model

BACKGROUNDAnodontia is described as the absence of all dental buds in primary, permanent or in both generations of dentition. This is due to contemporary lack of dental follicles at the same time. The dental follicles are known as a very reach source of various growth factors as BMP1, PDGF and others. The role of these growth factors seems to be very essential in maxilla and mandible bone formation as well as surrounding tissue health status. Anodontia is a disorder, which affects patient from the earliest childhood. This is why the complications of the lack of stimuli from the dental follicle growth factors are very long lasting in child maturation process and untreated may lead to huge skeletal abnormalities. The great expression of them are very difficult for patients from the aesthetic point of view because of the huge disproportion between upper, middle and lower part of the face and are so‐called the bird profile. This is a very significant sign and there is no possibility to hide it, so it can cause the social isolation of the patients and multiple psychotic disorders. The main aim of this research is to prove the influence of dental follicles growth factors on the development of porcine mandible, second is to describe the animal model of anodontia disorders in human.METHODSExperiments was performed on 6 newborn piglets born at term and without complications. The surgical procedures were conducted under the general anesthesia on the second day of piglets life. The triangular mucoperiosteal flap was prepared and elevated in the vestibulum of the oral cavity in order to perform the germectomy procedure. Afterwards, the vestibular lamina of bone covering piglets the first and the second deciduous molar tooth buds was removed. The removal of these buds and theirs folliculi was the next step of surgery. The closing suture of the wound has finished the procedure. The recovery period was 10 days with the five‐day antibiotic cover. Following surgery, the animals were held with their biological mothers (with litter) all‐time for three months the experiment. After the full experimental procedure, all animals were euthanized. Cone Beam Computer Tomography scans was made before and just after germectomy surgery as well as before the animal euthanasia was conducted.RESULTSPreliminary results of the study showed that the methodology of the proposed project is feasible. Animals tolerate the surgery and they do not have a significant impact on the further life piglets. Piglets are accepted by her mother and siblings, and very quickly return to everyday life in the group. The most valuable are the preliminary results of the mandible CT animals from a group of animals removed tooth germs. It has been shown that the removal of two molar tooth germs in 2‐day pigs (n=6) after three month causes highly significant (p=0.0072) reduction of the mandible 3.35±0.11 cm to 2.66±0.12 cm.[Marg1] What can we conclude from the results?CONCLUSIONThese results support the premise of the research that growth factors teeth buds in a highly significant stimulate the growth and development of the jaw.Support or Funding InformationThis research was supported by National Science Center Grant no. 2015/17/B/NZ9/01447This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Etiology of Various Dental Developmental Anomalies -Review of Literature

The development of the tooth involves many complex biological processes, including epithelial- mesenchymal interactions, differentiation, morphogenesis, fi brillogenesis and mineralization. After 37 days of development, a continuous band of thickened epithelium forms around the mouth in presumptive upper and lower jaws from the fusion of separate plates of thickened epithelium–primary epithelial band and gives rise to vestibular lamina and dental lamina [1].

Relationship between vestibular lamina, dental lamina, and the developing oral vestibule in the upper jaw of the field vole (Microtus agrestis, Rodentia)

Formation of the oral vestibule is ignored in most studies on tooth development, although dental and vestibular lamina are closely related to each other. Knowledge about morphogenetic processes shaping the oral vestibule is missing almost completely. The aim of this study was to assess the developmental relationship between dental and vestibular lamina as well as formation of the oral vestibule in the upper jaw of the field vole (Microtus agrestis), a small rodent representing an attractive model species for comparative dental studies. Three-dimensional reconstruction revealed that the upper vestibular lamina of the vole joins the antemolar part of the diastemal dental lamina, similar to mouse. Later, this lamina complex regresses and the vestibular lamina is separated from the molar epithelium. Participation of the vestibular lamina in dental lamina formation, as hypothesized for mouse, therefore remains unclear. Except for increased apoptosis in the regressing diastemal dental lamina, spatial segregation of mitoses or apoptoses could be detected neither in the jaw arch epithelium nor in the adjacent mesenchyme. Therefore, in contrast to tooth primordia, apoptosis and mitosis seem to play a minor role in shaping of the upper oral vestibule. The buccal vestibule develops secondarily, probably in consequence of general growth of the head and localized differentiation of cells.

The developmental relationship between the deciduous dentition and the oral vestibule in human embryos

In humans, there is no consensus about the developmental relationship between the deciduous dentition and the oral vestibule separating the teeth from the lips and cheeks. The classical concept assumes that two horseshoe-shaped epithelial structures exist: the dental lamina, giving rise to single tooth primordia, and the vestibular lamina running parallel and externally to it, giving rise to the oral vestibule. The aim of this study was to investigate the development of the dental and vestibular laminae in the upper jaw and to determine their developmental relationship in humans from embryonic week 6 to 9. Although a thickening of the vestibular epithelium was always present on serial histological sections, computer-aided three-dimensional reconstructions did not show any continuous vestibular lamina. Several discontinuous epithelial structures (bulges and ridges) occurred transiently at different stages of oral vestibule development. Along the mesiodistal axis, the dental and vestibular epithelia were regionalized in parallel: in the incisive, canine, and 1st and 2nd molar regions. The vestibular ridges fused with the dental lamina distally to the deciduous canine, 1st molar and 2nd molar. These interactions between the developing teeth and vestibular structures are reminiscent of the situation in some reptiles, where single teeth are paired one-to-one with single tooth glands.

Histological Study of Genesis of the Mice Oral Vestibule

Background: Both the vestibular lamina (VL) and dental lamina (DL) develop from the primary epithelial band of the oral cavity. Previous studies have reported that VL and DL were initiated by certain epithelial-mesenchymal interactions between the primary epithelial band of the oral cavity and underlying mesenchyme; however, the exact mechanisms remain to be elucidated. Aims: Here we studied how the retinoblastoma (Rb) family and E2 promoter binding factor (E2F) regulate signals that control and regulate the proliferation and differentiation of the VL leading to the formation of the oral vestibule. Methods: Immunohistochemical light microscopy by the enhanced polymer one-step staining(EPOS) method and confocal laser scanning microscopy by the LsAB labelled streptavidin biotin (LSAB) method were performed on the developing vestibular lamina(VL) of fetal mice at stages from 11 days after fertilization E11 to E14.The immunohistochemical findings were compared with the findings in the developing dental lamina (DL) and tooth germ. Conventional transmission electron microscopy was performed on the E13 fetuses, in an effort to elucidate the differentiation of keratocytes in the developing VL. Results: We found that: 1) EGF, TGF , EGFR, PCNA, FGF2, pRb, and FGFR1-4 were immunolocalized in the developing tissues. 2) Cytokine expression patterns indicated that the EGF family and FGF2 essentially induced VL generation and cell proliferation. 3) FGFR1 as diffusely localized in the primary epithelial band, but was strongly expressed in the E12-14 VL and DL/enamel organ. By contrast, EGFR internalization was observed in the differentiating E13 VL. 4) Expression of pRb was intensely localized in the suprabasal layer of the E13 VL corresponding to CK-10 expression and keratohyaline-containing structures in the VL stratum germinativum cells. Conclusions: We suggest a mechanism in which FGFR1 regulates pRb to induce proliferation of cells in the VL and DL/enamel organ, and, in particular, to incite keratocyte differentiation and subsequent exfoliation of keratinizing VL cells.

Immunohistochemical study of genesis of the mouse oral vestibule.

Immunohistochemical light microscopy by the enhanced polymer one-step staining (EPOS) method and immunohistochemical confocal laser scanning microscopy by the labelled streptavidin biotin (LsAB) method were performed on the developing vestibular lamina (VL) of fetal mice at stages from E11 to E14, and the immunohistochemical findings were compared with the findings in the developing dental lamina (DL) and tooth germ. pRb and PCNA were immunolocalized and found to be related to the temporal and spatial expression of cytokines and receptors in the primary epithelial band, VL, DL/enamel organ, and associated mesenchyme. The following results were obtained: 1) EGF, TGFalpha, EGFR, PCNA, FGF2, pRb, and FGFR1-4 were immunolocalized in the developing tissues. 2) Cytokine expression patterns indicated that the EGF family and FGF2 essentially induced VL generation and cell proliferation. 3) FGFR1 was diffusely localized in the primary epithelial band, but was strongly expressed in the E12-14 VL and DL/enamel organ. By contrast, EGFR internalization was observed in the differentiating E13 VL. 4) Expression of pRb was intensely localized in the stratum germinativum of the E13 VL and corresponded to CK-10 expression in the keratinizing VL. The results of this study suggest a mechanism in which FGFR1 regulates pRb to induce proliferation of cells in the VL and DL/enamel organ, and, in particular, to incite keratocyte differentiation and subsequent exfoliation of keratinizing VL cells.

The Lateral Enamel Lamina--Component of Tooth Primordia in Selected Mammalian Species

The lateral enamel lamina (LEL) is a part of the enamel organ, which is probably not involved in tooth formation. It represents, besides the "stalk" of the tooth primordium, a second interconnection between enamel organ and oral epithelium or vestibular lamina. We detected the LEL in the sheep ( Ovis aries ), the dolphin ( Stenella attenuata ), and the vole ( Microtus agrestis ) by light microscopy and computer-aided three-dimensional reconstruction. The LEL could be found in cap to bell stage tooth primordia, most clearly in slowly developing tooth germs. LEL-like structures have been furthermore described or depicted in tooth germs of the mouse, the elk ( Alces alces ), the dugong ( Dugong dugong ), the elephant ( Loxodonta africana ), and the human. Probably it is a part of all mammalian tooth primordia that undergoes regression during morphogenesis of the enamel organ. As a reducing structure, it should be considered in studies of tooth development.

The Primordium of the Upper Vestibulum Oris in the Domestic Sheep

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Observations on early development of the murine fetal oral vestibule.

Morphological and immuno/histochemical studies were performed on the vestibular lamina (VL) of gestational day 13 murine fetuses, using light microscopy (LM), confocal laser scanning microscopy (CLSM) and transmission electron microscopy (TEM), in an effort to elucidate the early development of the oral vestibule. Histochemistry employing LM demonstrated some PAS-positive glycogen particles in embryonic cells of the VL, dental lamina (DL), the primary epithelial band connecting the VL and DL, and the related stomodaeal simple epithelium. On the other hand, Gomori's aldehyde fuchsine method stained certain cystine-containing intracellular granules and intercellular amorphous substances, particularly in the central VL. Intense immunoreactivity for CK-10 intermediate-sized filament proteins was demonstrated in suprabasal and superficial cells of the VL stratified keratinized epithelium. Conversely, reactions for CK-19 filaments were found diffusely in both VL and DL cells retaining the cytokeratin characteristic of the simple epithelium. TEM of the VL revealed an increment in keratinosomes, tonofilaments and desmosomes in the suprabasal layers shifting toward superficial flat parakeratinized cells. The TUNEL method using CLSM detected programmed cell death in the VL, while TEM provided no morphological evidence of necrosis or typical apoptotic features during VL development. The present results indicate that physiological (naturally occurring) cell death and exfoliation of the oral-gingival type multilayered keratinizing epithelium are essential for degeneration and separation of the VL, ultimately leading to formation of the oral vestibule.