pathogenic microorganism in the oral biofilm or dental
plaque that accumulated around the teeth due to poor
oral hygiene [3, 4]. The evidences indicate that periodon-
tal diseases develop when the numbers of Gram-negative
bacteria and anaerobes in subgingival plaque increased
[20, 21]. Numerous research efforts were implemented
in order to identify bacterial species that are associated
with the periodontal diseases [22, 23]. The most com-
mon periodontal-diseases-associated microorganisms were
Aggregatibacter (Actinobacillus), Porphyromonas gingivalis,
Tannerella forsythensis, and spirochaete Treponema denticola
[2, 24–28]. Recent studies implicate fungi, such as Candida
albicans, and Herpes viruses in the pathogenesis of periodon-
tal diseases among immune-compromised children [29–31].
However, genetic, developmental, traumatic, neoplastic, and
metabolic factors contributed to the cause of these diseases [9,
11, 24]. Furthermore, some systemic diseases and medications
also have periodontal manifestations [2–4].
2.4. Classification. Over the last few decades, the nomen-
clature and classification of periodontal diseases changed
periodically [3]. Regardless of the causative factors, periodon-
tal diseases are divided into destructive and nondestructive
form [14]. Gingivitis is a reversible and nondestructive form
of periodontal diseases [14, 32, 33]. It is the inflammation
of the marginal gingiva that may progress to include free
and attached gingiva but causing no attachment loss [9,
11]. Based on clinical findings and diagnosis, gingivitis was
subdivided into infectious and noninfectious forms as in
Figure 1 [14, 34–37]. On the other hand, the irreversible
and destructive form of periodontal diseases is periodontitis
[14]. It is the inflammation of the tooth supporting tissue,
which is accompanied by loss of connective tissue attachment
and breakdown of the supporting alveolar bone [9, 11].
Periodontitis may progress to cause exposure of the roots,
mobility, and premature loss of the teeth [9]. In 1989, the
American Academy of Periodontology set criteria in order to
distinguish various forms of periodontitis [3]. Those criteria
are (1) age at onset, (2) distribution of the sites affected
by the disease, (3) presence or absence of the systemic
diseases, (4) rate of the disease progression, (5) response to
treatment, and (6) presence or absence of specific host or
microbial factors (the consensus of the world workshop in
clinical periodontics) [3]. The most recent classification of
periodontal diseases was introduced in 1999 by international
workshop of periodontology and includes greater variety
of periodontal diseases categories [3, 38, 39]. However, this
paper will not follow specific classification system but rather
will focus primarily on the periodontal diseases that are most
commonly seen in pediatric dental patients.
2.4.1. Gingivitis. As mentioned earlier in this paper, gingival
problems, either in acute or chronic nature, are nearly
universal among children and adolescents [19]. Diagnosis
of various types of gingivitis relied mainly on the clinical
findings and manifestations [3, 32]. Those findings include
redness and edema of the marginal gingiva and bleeding
upon probing [2–4]. As disease persists, gingival margin
may become rolled, interdental papilla may become enlarged
and bulbous, bleeding may start spontaneously, and probing
depth may increase as a consequence of gingival overgrowth
(hyperplasia and hypertrophy) [2, 3, 32, 34].
Histologically, ulceration of the sulcular epithelium was
observed both in children and in adolescents [32, 34]. How-
ever, researchers have noted predominance of T-lymphocyte
infiltrate in gingivitis in children compared to B-cell (plasma
cells) infiltrate in gingivitis in adolescents (Ranney et al., 1981,
and Page and Schroeder, 1976) [3, 4]. Although the microbi-
ological picture of gingivitis in children and adolescents has
not been completely characterized, certain bacterial species
have been found in experimental studies [4]. Those species
were Aggregatibacter (Actinobacillus) sp., Capnocytophaga
sp., Leptotrichia sp., and Selenomonas sp. [27, 28].
Gingival problems that are commonly see