Scanning Electron Microscopy of Angioarchitecture of Palatine Gingiva in Young Rabbits
Marcia Consentino KRONKA
Ii-sei WATANABE
Marcelo Cavenaghi Pereira da SILVA
Department of Anatomy, Institute of Biomedical Sciences, University of São Paulo, São Paulo, SP, Brazil
Correspondence: Dra. Marcia Consentino Kronka, Departamento de Anatomia, ICB III, Universidade de São Paulo, Caixa Postal 66208, 05389-970 São Paulo, SP, Brasil. Tel: +55-11-3818-7258. Fax: +55-11-3818-7366. e-mail: makronka@usp.br
Braz Dent J (2001) 12(3): 163-166 ISSN 0103-6440
INTRODUCTION | MATERIAL AND METHODS | RESULTS | DISCUSSION | ACKNOWLEDGEMENTS | RESUMO | REFERENCES
The angioarchitecture of young rabbits’ palatine gingiva was studied by using
the corrosion resin cast method. The vascular corrosion casts were obtained
using low viscosity resin (Mercoxâ CL-2B) and were observed with scanning
electron microscopy (SEM). The palatine gingiva had areas with various arrangements.
The capillaries of the palatine gingiva and interdental papillae had numerous
projections, but in the gingival sulcus, the blood vessels were arranged
in a flattened network from their capillary extremities. The blood vessels
supplying the alveolar bone were also clearly seen.
Key Words: palatine gingiva, alveolar bone, rabbits, angioarchitecture, SEM.
INTRODUCTION
The mucous membrane that protects the hard palate as well as the palatine
gingiva has been characterized as masticatory mucosa (1-3). The lining epithelium
is keratinized, squamous and stratified tissue and the interface of epithelium/connective
tissue has numerous connective papillae (4).
According to McCuskey and Krasovich (5), the microvascular system brings
the blood to the cells of organs, and provides the substances for the maintenance
of an optimal microcirculation and thus, organ function. The close relationship
between the complexity of microvascularization and functions of the tissue
or organs was reported by Konerding (6) and McCuskey and Krasovich (5).
Jasinski and Miodonski (7) detected peculiar vessels in the palatine mucosa
suggesting their involvement in gas exchange. Recently, Kronka (8) reported
that a subepithelial vascular network was formed just below the epithelium
in the palatine mucosa, showing capillaries directed to connective papillae.
Furthermore, the microvascularization of the palatine mucosa contained larger
vessels located deeper in the tissues (8).
Due to the importance of the integrity of palatine gingiva especially in
Dentistry, the aim of this study was to analyze the three-dimensional characteristics
of vascular arrangement related to tooth and adjacent alveolar bone using
scanning electron microscopy.
MATERIAL AND METHODS
Seven young (15-45 days old) rabbits of both sexes were prepared for scanning
electron microscopy. The animals were carefully anaesthetized with iv injection
of sodium pentobarbital (30 mg/kg body weight). A polyethylene tube was introduced
into the aorta for both perfusion and resin injection.
Perfusion was done with prewarmed heparinized saline (500 ml, 37°C) until
the reflux out from the right atrium was similar to this rinsing solution.
Subsequently, 30 ml of low viscosity resin (Mercoxâ CL-2B, Dainippon-ink
Chemical Co. Ltd., Tokyo, Japan) prepared according to the manufacturer’s
instructions was injected with manual pressure.
The specimens were maintained at room temperature for approximately 2-3 h
until resin polymerization was complete. They were then macerated in 10%
sodium hydroxide solution for 3-5 days at room temperature. The vascular
corrosion casts were rinsed in distilled water, dried, mounted on metal stubs
and coated with gold. The material was observed with a JEOL 6100 scanning
electron microscope.
RESULTS
The vascular corrosion casts demonstrated the angioarchitecture of the young
rabbits’ palatine gingiva and its association with alveolar bone. The microvascular
systems of palatine gingiva, interdental papilla and gingival sulcus are
shown in Figures 1 and 2. The distribution of several projections coming
from fine superficial vessels related to palatine gingiva and to interdental
papillae (Figures 1 and 2) followed the gingival margin. At the level of
the gingival sulcus, the fine blood vessels formed a flattened network (Figure
2) that followed the dental surface without projections (Figure
3). The capillaries
showed numerous anastomoses.
The microcirculation of the palatine gingiva revealed vessels with different
diameters (Figure 4) that ran close to the surface of the alveolar bone with
branches running into the vascular bone foraminae (Figure
5).
DISCUSSION
The results of this study clearly showed the distribution of capillaries
in the palatine gingiva and interdental papillae. Numerous capillaries were
encountered in the tissue that surrounds the teeth.
Lametschwandtner et al. (9) assumed that angioarchitecture means the three-dimensional
arrangement of all vessels. Furthermore, the use of vascular corrosion casts
in association with scanning electron microscopy may reproduce the vascular
network and permit the morphological study of the microcirculation (10).
The technique was originally described by Tanigushi et al. (11) and later
modified by Murakami (10). The present study also demonstrated the benefits
of this method, revealing the spatial arrangement of the microvessels of
the palatine gingiva.
Despite of the fact that the animals were young, the palatine gingiva had
a dense, complex vascular structure. Skaladzien et al. (12) reported that
the underdevelopment of some vascular areas of the nasal mucosa in the human
fetus is associated with the functional immaturity of the respiratory system.
Strek et al. (13) observed that the microvasculature of the dorsal mucosa
of the human fetal tongue is similar to that described for the tongue of
children aged 6 months to 2 years. Naccarato et al. (14) examined the vascular
network of well developed areas in adult gerbil nasal septum showing the
presence of numerous arteriole and venule. Makiyama et al. (15,16) compared
the angioarchitecture of the tongue of normal and malnourished young rats
and found no significant differences.
Kindlová (17), studying the vascular bed of the marginal periodontium
of rat molars, detected that although there is continuity of microvascular
systems in a developed periodontium, they retain their structural differences.
The present study shows the different arrangements of microcirculation at
3 regions of young rabbit palatine gingiva. Kindlová (17) also noted
proximity between blood vessels and alveolar bone, finding branches entering
the gingival epithelium. Our results showed thick vessels supplying both
palatine gingiva and alveolar bone with capillary branches of different diameters.
Weeks and Sims (18), studying ageing rats, also noted a flattened network
subjacent to the sulcus epithelium, with twisted vascular loops situated
on buccal and lingual crevices which were slightly different compared to
our data obtained with young rabbits, in which we observed simple hair-pin
capillary loops.
The association between scanning electron microscopy and vascular corrosion
casts makes the three-dimensionality of palatine gingiva microvasculature
in young rabbits evident. The angioarchitecture showed a close relationship
between microvessels and the superficial shape of teeth and indicates the
need for careful manipulation of palatine mucosa.
ACKNOWLEDGEMENTS
This research was supported by FAPESP (99/09361-7) and CNPq (301425/88).
RESUMO
Kronka MC, Watanabe I-s, Silva MCP. Microscopia eletrônica de varredura
da angioarquitetura da gengiva palatina de coelhos jovens. Braz Dent J 2001;12(3):163-166.
A angioarquitetura da gengiva palatina de coelhos jovens foi estudada utilizando-se
o método de modelos de corrosão vascular. Os modelos de corrosão
foram obtidos a partir da injeção de resina de baixa viscosidade
(Mercoxâ Cl-2B) sendo, posteriormente observados ao microscópio
eletrônico de varredura (MEV). A gengiva palatina apresentou áreas
de diferentes disposições vasculares. Os capilares da gengiva
palatina e da papila interdental emitiam diversas projeções,
não detectadas, porém, no sulco gengival, onde a rede capilare
mostrava-se de arranjo irregular, aplainado. Os vasos sangüíneos,
nutrindo o osso alveolar, também foram observados.
Unitermos: gengiva palatina, osso alveolar, coelhos, angioarquitetura, MEV.
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Accepted December 19, 2000
