Periodontium in children
Introduction : The structure of the periodontium of children is very similar to that of adults. The periodontium is a functional and evolving unit consisting of the supporting tissues of the tooth, gingiva, cementum, bone and desmodontium. We can initially consider that the structure of the periodontium of children is identical to that of adults. However, the development of the dentition and certain problems specific to childhood encourage us to study the facts concerning gingival and periodontal problems in children from a particular perspective.
1-periodontium of the child:
-Gingiva : in children, the gum is firm pink, often the vascularization is more important and results in a reddish color. The appearance of this gum is smooth or granite. The interdental gingiva is wide in the vestibulo-lingual direction but narrower in the mesio-distal direction, the edge of the free gingiva is thicker and rounded. As in adults, there is a depression or collar which is interposed between the vestibular papilla and the lingual papilla. The average depth of the gingivodental groove in temporary dentition is equal to 2.1 mm. This collar is covered with a thin and non-keratinized stratified epithelium. (This explains the fragility of this area during inflammatory processes. During the transitional period of the development of the dentition, transformations occur in the gum, at the time of the eruption of the permanent teeth.
According to Glickman the physiological transformations are:
– pre-eruptive swelling: the gum presents a firm swelling which follows the contour of the underlying crown.
-formation of the gingival margin: the marginal gingiva and the groove develop following the progression of the crown in the oral mucosa.
Normal prominence of the gingival margin: During the mixed dentition period the marginal gingiva is quite prominent around the permanent teeth. The gingiva is still adherent to the crown and it adds to the volume of the underlying enamel.
-Alveolar bone : In children, the alveolar ridges are less tapered than in adults. The trabecular bone is not very dense, with wide medullary spaces. Blood and lymphatic vascularization is very important. The lamina dura is thin. It is at the end of the second month of intrauterine life that the interdental septa begin to develop. Alveolar growth is particularly rapid at the time of eruption at the level of the free peri and inter radicular edges. This alveolar bone comprises two parts:
- the alveolar bone itself (lamina dura, cribriform plate) which is a thin bony lamella into which the fibers of the ligament (dental socket) are inserted.
- the thicker supporting alveolar bone which includes the spongy bone and the compact bone.
The alveolar bone shows remarkable physiological adaptation during the replacement of the deciduous dentition by the permanent dentition.
Thanks to the coordinated phenomena of formation and resorption, the bone changes structure (lamellar, spongy, Haversian type). On the other hand, the teeth present movements during life which makes it possible to compensate for the phenomena of occlusal and proximal abrasion. Root growth alone is not sufficient to put the crown in occlusion with the antagonist. Bone growth provides decisive help: bone apposition at the bottom of the alveolus, growth of the distal wall of each alveolus, alternation of resorption and apposition at the level of the mesial wall.
-The desmondote : In adults as in children, the desmondote is a specialized connective tissue. The alveolo-dental ligament is wider than in adults and visible on X-rays. Its fiber bundles are not very dense and the blood and lymphatic vascularization is important. The desmodont has three layers:
-an external pre-alveolar layer of collagen fibers anchored in the lamina dura.
-an intermediate layer of fibers.
-an internal pre-radicular layer of collagen fibers inserted into the cementum.
Periodontium in children
– Cementum: Overall, the cementum of temporary teeth appeared similar to that of permanent teeth. In the coronal part of the root, acellular cementum dominates while the cementum of the apical part is mainly of the cellular type. The crystals observed are flattened and oriented in such a way that their longitudinal axis is parallel to the longitudinal axis of the collagen fibers. It is also noted that there are no growth lines with a high content of mineral substances and that the cellular cementum is thinner than that of permanent teeth. Under the electron microscope, the cementocytes placed near the surface of the cementum resemble cementoblasts, with the particularity of a decrease in the quantity of cytoplasm. In the apical region, the cementoblasts present the typical characteristics of active cells. The cementocytes included in the calcified matrix, present fewer organelles.
2-Occlusion of the child :
Temporary dentition:
The relationships of teeth to each other and of arches to their antagonist vary during childhood and adolescence. Some authors admit different stages in the morphogenesis of dental arches with dynamic and static phases. It is possible to consider periods of activity (eruption) and periods of stability during which the dental formula remains the same for several years.
In general, diastemas can exist in the incisor-canine region of the temporary dentition, they are localized
-on the upper arch between the lateral incisor and the canine.
-on the lower arch between the canine and the first molar.
Mixed dentition:
The mixed dentition begins with the appearance of the first permanent molar or with the spontaneous loss of the first of the temporary teeth, usually a lower central incisor. This is an extremely active period of periodontal remodeling.
The evolution of the permanent lower incisors occurs naturally on the lingual side. During this period, the practitioner may see inversions of articulation forming which he will have to correct at this stage.
The first permanent molars erupt in the most posterior position. If there is a space between the canine and the first temporary molar on the mandibular arch, the eruption of the first permanent molar will pull the deciduous molars towards the anterior part, obliterating the diastema and thus allowing the mandibular molar to erupt directly in normal occlusion.
If, on the other hand, there is no free space on the arch of the primary teeth of the mandible, the maxillary and mandibular molars will be placed end to end until the second deciduous molar is replaced by the narrower second premolar.
3-Structural anomalies :
Genetics : Some gingival abnormalities evolve during the eruption process. Gingival hypertrophies are caused by the superposition of the gingival mass on the natural protuberance of the enamel contained in the gingival half of the crown. These hypertrophies can be complicated by marginal inflammation to the point of giving the impression of extensive gingival hypertrophy.
Bridles and frenums : the study of the gingiva also includes the examination of the labial and lingual frenums which are mucous or fibromucous.
Abnormal, atypical frenulums can be located in different vestibular areas. They are either wide or narrow and may contain muscle fibers from facial muscles.
-Maxillary labial frenum: its hypertrophy plays an important role in the etiology of maxillary interincisive diastema. The frenum begins its development in the 3rd month of intrauterine life.
During development, it atrophies and due to the development of the alveolar rim a separation between the frenulum and the palatine papilla forms.
– Mandibular labial frenum: When it is inserted on the edge of the free gingiva, it causes traction on the latter during movements of the cheeks and lips. The resulting gingival detachment can lead to the total loss of the attached gingiva on the vestibular side. Similarly, the action of a frenum on a periodontal pocket accelerates the development of lesions.
-Lingual frenulum: At birth, the frenulum often extends to the tip of the tongue. During growth, the tip of the tongue lengthens without the insertion of the frenulum changing.
Periodontium in children
Dental malposition : poorly aligned teeth and malformations of the jaw promote periodontal disease by causing a certain number of abnormal occlusal relationships on the one hand and an accumulation of irritating food debris on the other.
Gingival recession is often associated with vestibular movement of teeth. The incisal edges of the anterior teeth often cause irritation of the opposing gingiva in patients with supracclusia. An open bite can lead to significant periodontal changes .
Acquired:
Dental caries : They play an important role in periodontal inflammation. They associate
-mechanical irritation of the marginal periodontium by the sole presence of the carious cavity
-food compressions that cause painful septicaemia
-microbial irritation of caries.
In decayed and treated teeth, iatrogenic factors are sometimes decisive. Incompletely treated or poorly treated teeth are major causes of periodontal inflammation: (overflowing fillings, defective contact points, poorly adjusted crowns, deficient filling materials, etc.)
4-Bacterial flora:
At birth, the oral cavity is free of bacteria. It is on the 2nd or 3rd day that the permanent bacterial flora is established, where streptococci, lactobacilli and veillonella predominate.
It is between 4 and 8 months that the number and variety of bacteria increase and up to 12 months aerobes predominate.
At this age, the flora is practically the same as that found in adults, including anaerobes (strepto mutans appears after the first year). Contamination of the oral cavity occurs through the environment, food, air and water.
5- Particularity of inflammation in children : In young children, gingivitis develops much more slowly than in adults for a given volume of bacterial plaque (cox et al). The onset of periodontitis with alveolysis is very rare in the primary dentition and suggests Papillon-Lefèvre disease, hypophosphatasia or cyclic neutropenia. There is better apparent resistance of the child’s tissues to the development of periodontal lesions. Longhurst et al showed that in gingivitis in children aged 3 to 7 years, monocytes, macrophages and polymorphonuclear cells were found. Lymphocytes are in large numbers and mast cells are very few. This is the opposite of what happens in adults where mast cells predominate.
For Hausmann, the relative resistance of the periodontium in children would be due to:
– either to very active repair mechanisms.
– a barrier preventing the passage of alveolysis factors.
Bibliography:
-M.YARDIN C.BIGGARE infantile periodontics EMC 23415 C10 4-1980
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