PATHOLOGIES OF THE IMMATURE PERMANENT TOOTH

PATHOLOGIES OF IMMATURE PERMANENT TOOTH:

 

1. Definition of immature permanent tooth:

An immature permanent tooth is a tooth present in the arch whose apical cemento-dentin junction is not yet in place.

PATHOLOGIES OF THE IMMATURE PERMANENT TOOTH

1. Chronology of maturation of permanent teeth (stages of Nolla 1960): 

• Stage 0: absence of crypt
• Stage 1: presence of crypt.
• Stage 2: initial calcification.
• Stage 3: 1/3 of the crown built.
• Stage 4: 2/3 of the crown built.
• Stage 5: crown almost complete.
• Stage 6: crown completed.
• Stage 7: 1/3 of the root built.
• Stage 8: 2/3 of the root built (eruption, blunderbuss shape).
• Stage 9: root almost complete (open apex, cylindrical shape).
• Stage 10: apical end of the root completed, JCD in place.

Referring to the average age of eruption of permanent teeth and the Nolla tables, we can say that the teeth erupt on the arch at Nolla stage 08 (root reached 2/3), approximately 3 to 4 years elapse between the eruption of the tooth and its maturation. 

2. Anatomical and physiological characteristics of immature permanent teeth:
3. Anatomical features:
4. the crown: its morphology is eventful, the cusps pronounced, the furrows deep and crevices, presence of wells dug in the enamel (zone of least resistance).

• Enamel: Early vulnerability to caries of immature permanent teeth is due primarily to the immaturity of the enamel which has not yet undergone post-eruptive maturation (precipitation of calcium phosphate and calcium fluorophosphate).

In front of this immature enamel with a porous surface, the plaque adheres strongly to it.

1. Dentin:

• has a fragile, thin and poorly mineralized structure (but secondary dentin is gradually deposited over the course of life, it provides significant thickness at the same time as hypercalcification which reinforces resistance against caries).
• The dentinal tubules are widely open: this promotes the rapid proliferation of caries once the enamel-dentin junction is crossed.

PATHOLOGIES OF THE IMMATURE PERMANENT TOOTH

2. the root:

• Frail in appearance, more or less short depending on the stage of development.
• The dentin walls are thin (fragile).
• The pulp cavity: the pulp chamber is large and the root canal is very wide.

• The pulp horns are high.
• The canal is wide, flared in the sense that the apical end is wider than the cervical end (blunderbuss).  
• The apex is widely open, gaping: apical funnel.

C. immature pulp: the pulp mass is voluminous and consists of young connective tissue with excellent repair potential.

It is characterized by immature innervation which contributes to making the young permanent tooth less sensitive to various external stimuli.

D. the periodontium of an immature permanent tooth:

• When the permanent tooth comes into occlusion:
  • The cervical ligament fibers are formed.
  • The horizontal and apical fibers are immature.
• It will take 3 to 4 years after tooth eruption for the periodontal ligament to reach maturity.
• The vascular potential of the immature ligament is significant. 

E. the apical 1/3 of an immature permanent tooth: 

• The apical 1/3 in formation is a “funnel” opening.
• Wide root canal.
• The walls are very thin and fragile.
• The radiographic appearance of the immature permanent tooth is divided into 03 groups, according to the stage of root formation:
  • Teeth with divergent walls towards the apex (stage 08).
  • Teeth with parallel walls (stage 09). 
  • Teeth with walls converging towards the apex. 

2. Physiological characteristics:

a). stage 08: the tooth erupts at Nolla stage 08, at this stage:

• 2/3 of the root is built
• the pulp chamber is wide.
• Gaping apical opening in a “blunderbuss”; the apical end wider than the cervical end unlike the mature permanent tooth.

b). stage 09: rhisagenesis is almost complete but with an apex still open.

c). stage 10: root maturation:

• Cemento-dentin junction in place.
• Apex punctiform.

The alveolar-dental ligament has not yet reached maturity.

NB: a period or duration of 3 to 4 years is required for the maturation process to take place.

d). physiology of the apical region:

• It is a richly vascularized region, it participates directly in the construction of the apical 1/3 as soon as the crown is completely formed.
• Root formation is carried out through the Hertwig epithelial sheath (proliferation of internal and external adamentine epithelium). 
• The epithelial cells of the adamentine epithelium have an inductive power on the cells of the neighboring connective tissue (differentiation into odontoblasts and elaboration of the root dentin up to the normal root length).
• The Hertwig sheath thus participates in the formation of the apical orifice by centripetal horizontal growth and in the elongation of the root by evolution in a vertical direction.
• As soon as the root reaches its final length, the Hertwig sheath disintegrates into Malassez epithelial debris.
• The absence of apical construction means that the nerve pathways are not compressed during inflammation and contributes to the absence of pain.  

3. Pathologies of immature permanent teeth:

The pathologies that particularly affect the immature tooth are: carious disease, hypomineralization of molars/incisors and trauma.

1. The carious lesion: 

Definition : 

Caries is a localized pathological process of bacterial origin, which leads to the demineralization of the hard tissues of the tooth and the formation of a cavity.

Caries begins with a microscopic lesion which can progress to the formation of a macroscopic cavity.

Epidemiology: 

Tooth decay is still the most common disease in children today, it is no longer a pandemic but remains concentrated in a few children, on certain teeth and constitutes a public health problem.

The prevalence of this disease reached its peak in the 1970s in industrialized countries. The CAD index at 12 years reached 5.4 in 1974. Since then its values ​​have improved from 4.2 in 1987 to 1.23 in 2006.

The first molar is the tooth most affected by carious disease at an early age, most heavily and most frequently; in fact, the CAD index of the latter at 12 years represents 70% of that of the entire mouth. In 2010, more than half of 12-year-old children had at least one lesion on the occlusal surface of the first molar.

           Why the 6 year old tooth? 

 The 6-year-old tooth is the first permanent tooth affected by dental caries for the following reasons:

• The first permanent tooth to erupt.
• Special coronal anatomy: deep and anfractuous grooves, as well as pits which are also present on the smooth vestibular faces for the lower molars and for the upper molars. (which constitute a site for microorganisms).
• Presence in some cases of a mucous cap distal to the tooth (site for microorganisms).
• Tendency to abuse carbohydrates by children (ideal substrate for microorganisms).
• Inadequate oral hygiene measures during early childhood.
• Coincidence of infant molars, may be confused with a temporary tooth. 

     The diagnosis of a carious lesion on the DPI is urgent; it is essential to stop the progression of the caries as quickly as possible and to preserve pulp vitality in order to allow physiological root development and promote harmonious development of the arches.

    The carious lesions of the immature permanent tooth are very similar to those observed in adults but it is possible to individualize them by particular forms:

Clinical forms: 

Two clinical forms mainly concern DPI: progressive caries of the grooves, pits and fissures, the so-called hidden or surprise carious lesion and surface or creeping caries.

• Progressive caries:

• Observed at the level of the wells, cracks in the molars.
• Caries begins at the bottom of V-shaped, I-shaped or teardrop-shaped crevices, inaccessible to the mechanical and chemical actions of oral hygiene. The diagnosis of these early lesions, invisible both clinically and radiologically, is delicate and requires new diagnostic aid techniques based on fluorescence. 
• Surprise or hidden caries: these are extensive occlusal caries in width and depth that develop under the surface of the enamel.
• This development often occurs without painful symptoms.
• A small hole discovered during a probe examination often results in a large area of ​​unsupported enamel.
• Clinically, the enamel surface appears intact or minimally perforated but the lesion is very visible radiologically.

PATHOLOGIES OF THE IMMATURE PERMANENT TOOTH

• Surface or creeping caries:

• Observed on the vestibular surfaces of the incisors and canines and on the vestibular necks of the premolars and molars.
• The lesion gradually spreads on the surface and in depth.

PATHOLOGIES OF THE IMMATURE PERMANENT TOOTH

2.  Molar-incisor hypomineralization (MIH): 

Hypomineralization of molars and incisors corresponds to a weakening and alteration of the quality of the enamel. This pathology affects approximately 15% of children and makes them more vulnerable to the risk of caries.

          Hypomineralization of molars and incisors: what is it?

Referred to as MIH, it is a structural defect in the enamel. The affected teeth have an isolated opacity, ranging in color from white/cream to yellow/brown. Exceptional in the 1970s, this anomaly now affects 15% of children aged 5-7, according to Dr. Jean-Patrick Druo, president of the French Society of Pediatric Odontology. A prevalence that is increasing and can exceed 40% in Brazil!

“MIH mainly affects the first permanent molars and incisors. Its management must be early because hypomineralization:

• Causes dental hypersensitivity;
• Promotes the development of caries;
• Makes anesthesia and therefore dental care more difficult.”

PATHOLOGIES OF THE IMMATURE PERMANENT TOOTH

The severity of the damage varies from one child to another, from one tooth to another. It may be limited to a few spots, but the enamel may also be almost non-existent and the tooth may tend to crumble. Generally speaking, the more molars are affected, the greater the risk of caries.

Unfortunately, parents often alert themselves very late, more worried by the unsightly nature of this anomaly than by its cariogenic potential. In addition, molar incisor hypomineralization looks very similar to fluorosis, an excess of fluoride that also causes opacity on the teeth. The difference? “Fluorosis causes symmetrical lesions, unlike MIH,” explains Dr. Druo.

3. Trauma: 

• From an epidemiological point of view, the most frequent traumas affect the upper incisor-canine block.
• In permanent teeth, 19 to 40% of children aged 6 to 12 are affected by dental trauma (sport, accident, fights).
• Children aged 8 to 10 are an age group targeted by oral trauma, with over 81% of injuries affecting the upper central incisors.
• The damage affects both dental and periodontal tissues. The lesions created on the pulp tissue combined with those of the cementum, desmodontal cells and bone cells, generate resorptive phenomena that can result in tooth loss.
• Oral trauma is subject to numerous classifications according to various factors such as etiology, anatomy, pathology or therapy.
• The classification used today is that adopted by the WHO (1978). see course dental trauma 
• These traumas can be:
  • At the origin of direct pulp exposure (penetrating coronal or coronal-radicular fracture). 
  • Periodontal damage (damage to the apical vascular-nervous bundle: dislocation, expulsion, intrusion).

Conclusion : 

Any pathology (caries, trauma) of the immature tooth forces us to reconsider our conservative therapies according to the stage of root and apical formation. 

Our interventions will therefore focus on evolving structures and our primary goal will be to enable dental and alveolar formations to complete their construction. 

Dental crowns are used to restore the shape and function of a damaged tooth.
Bruxism, or teeth grinding, can cause premature wear and often requires wearing a retainer at night.
Dental abscesses are painful infections that require prompt treatment to avoid complications. Gum grafting is a surgical procedure that can treat gum recession. Dentists use composite materials for fillings because they match the natural color of the teeth.
A diet high in sugar increases the risk of developing tooth decay.
Pediatric dental care is essential to establish good hygiene habits from an early age.
 

PATHOLOGIES OF THE IMMATURE PERMANENT TOOTH