Pulp therapy for non-vital teeth

Question 1

Techniques includes:

Answer 1

1. Calcium hydroxide apexification
2. Mineral trioxide aggregate plug ( MTA) technique
3. Regenerative endodontic technique

Question 2

POSTERIOR IMMATURE TEETH

Answer 2

Saving posterior immature teeth is considered in selected cases where the preservation of the tooth is crucial for the occlusion

Extraction of non vital immature first permanent molars is usually the recommended approach; with careful orthodontic assessment

The patient’s oral hygiene, motivation, caries risk, and periodontal health should be carefully considered

Question 3

Calcium hydroxide apexification

Answer 3

Technique first introduced by Kaiser and Frank in the 1960s

This technique aims at inducing a calcified barrier in a root with an open apex through the use of calcium hydroxide as an intracanal medicament

High pH (btw 12.5 and 12.8) of CaOH makes it bactericidal, able to initiate a zone of liquefaction and coagulation necrosis adjacent to the healthy apical tissues
This results in the formation of a cementum-like structure acting as a calcific barrier

Question 4

Disadvantages of Calcium hydroxide apexification

Answer 4

Prolonged use of calcium hydroxide in the root canal increases the risk of root fractures due to the high alkalinity of calcium hydroxide which denatures the collagen of the dentin specifically by interfering with the phosphate and the carboxylate groups within the dentinal proteins

This technique also requires application of calcium hydroxide at 3-monthly intervals for 6–18 months with an average of 9 months . Therefore, this technique is associated with higher cost, patient taking time off school, and parents taking time off work

Question 5

The speed of apical barrier formation was shown to be dependent on:

Answer 5

1. Frequency of calcium hydroxide application
2. Patient’s age apical foramen width.
3. Severity of the trauma.
4. Presence of an abscess and periapical radiolucency

Histologic studies had shown the presence of numerous vascular channels into the calcific barrier (“Swiss cheese” like) which could lead to bacterial invasion and leakage of filling materials (sealers)

The calcific barrier does not always form at the radiographic apex of the tooth. (86.2% within 0–1 mm)

Question 6

Mineral trioxide aggregate plug technique ( MTA)

Answer 6

Mineral trioxide aggregate (MTA) was developed at the beginning of the 1990s at Loma Linda University in California and has since been used widely in pulpal management of immature permanent teeth

There are some differences among published studies regarding the chemical composition of MTA with incorporation of tricalcium silicate, tricalcium aluminate, calcium silicate, tetracalcium aluminoferrite, and bismuth oxide

Question 7

Advantages and disadvantages to the use of MTA.

Answer 7

Advantages:
1. Reduced number of dental visits
2. Good biocompatibility
3. Prevents microleakage
4. Induction of odontoblasts and hard tissue barrier
5. Capacity to set in a moist environment
6. Radiopacity that is slightly greater than dentine
7. Low solubility

Disadvantages of using MTA
1. Highly pH of 12.5 after setting may denature dentine collagen, potentially leading to root fracture especially in immature thin roots

2. Discoloration of the crown which is linked to bismuth oxide content
3. Setting time of 3–4 hours
4. Compressive strength after setting is 70 MPa.

Question 8

Apexification vs MTA plug technique

Answer 8

Due to the weak, unreliable evidence supporting the use of calcium hydroxide in multi-visit apexification in traumatized necrotic immature anterior teeth, coupled with the recent evidence showing negative effect of long-term calcium hydroxide use of dentine fracture strength, the use of calcium hydroxide is no longer the technique of choice when managing immature non vital teeth.

The use of a MTA plug technique in the last decade has improved the outcomes of managing immature non vital teeth . Nevertheless, MTA’s high alkalinity could result in tooth brittleness and future root fractures; therefore, research on the long-term effect of this technique is needed

Question 9

REGENERATIVE ENDODONTIC TECHNIQUE

Answer 9

The ultimate objective of REPs is to regenerate the pulp-dentin complex, extend the tooth longevity and restore the normal function

In order to achieve any qualitative increase in root dimensions, it would be essential to restore the blood supply to the tooth that was disrupted

Similarly, in trauma cases, a viable epithelial root sheath of Hertwig is required for consolidation of root length and increase in the crown-to‐root ratio therefore, continued root development is less successful in trauma cases due to damage to the epithelial root sheath of Hertwig

Question 10

Irrigation

Answer 10

The root canal system is irrigated with: copious amounts of 2.5% sodium hypochlorite. When irrigating with NaOCl, the needle should be introduced into the root canal to a point 2 mm short of the apical foramen, and the NaOCl is slowly expressed from the syringe to prevent its introduction into the periapical tissues

Followed by 5 mL sterile saline
The canal is dried using paper points
Metronidazole (100 mg) and ciprofloxacin (100 mg) should be mixed with distilled water
The mixture of the two antibiotics is filled into the root canal
A cotton pellet is placed to cover the root canal orifice and the access sealed with a glass Ionomer cement to prevent any coronal leakage or contamination of the root canal with oral microorganisms

2nd appointment
The antibiotic mixture is flushed out of the root canal by irrigation with: copious amounts of normal saline followed by 10 mL 17% EDTA.
The root canal is thoroughly dried with paper points

Insert a sterile sharp instrument (needle or a finger spreader) with a length of 2 mm beyond the working length , past the confines of the root canal, into the periapical tissues to intentionally induce bleeding into the root canal.
The bleeding is allowed to fill the root canal. Once the root canal is filled with blood, a cotton pledget is placed in the pulp chamber and a clot allowed to form in the root canal

Once the clot has formed, the pulp chamber in the coronal part is thoroughly cleaned to remove any remnants of blood, which could cause discoloration in the future.
The access cavity is hermetically sealed with three layers of material to prevent coronal leakage and contamination; Portland cement, followed by glass ionomer and then composite resin . Bleaching of nonvital discolored