Direct pulp capping is a minimally invasive endodontic procedure used to preserve the vitality of the tooth's pulp when it is exposed due to caries or trauma. The goal is to induce a biological response that leads to the formation of dentin-bridge to seal the pulp and prevent further infection.

Indications:
- Cariously exposed pulp that is asymptomatic and has no evidence of irreversible pulpitis.
- Recent traumatic exposure of the pulp with no signs of necrosis or infection.
- Presence of a thin layer of residual dentin over the pulp.

Contraindications:
- Signs of irreversible pulpitis or pulpal necrosis.
- Presence of a deep carious lesion that may lead to pulpal exposure during restoration.
- Large pulp exposures or when the pulp is exposed for an extended period.
- Immunocompromised patients or those with poor oral hygiene.

Procedure:
1. Local anesthesia: Numb the tooth and surrounding tissue to ensure patient comfort.
2. Caries removal: Carefully remove caries and any infected dentin using a high-speed handpiece with water spray to prevent pulp exposure.
3. Hemostasis: Apply a mild hemostatic agent if necessary to control bleeding.
4. Pulp conditioning: Apply a calcium hydroxide paste or a bioactive material to the exposed pulp for a brief period.
5. Application of the capping material: Place a bioactive material, such as mineral trioxide aggregate (MTA), calcium silicate, or a glass ionomer cement, directly over the pulp.
6. Restoration: Seal the tooth with a temporary restoration material and place a final restoration (usually a composite resin) to protect the pulp from further trauma.
7. Follow-up: Monitor the tooth for signs of pain, swelling, or discoloration. If these symptoms occur, a root canal treatment may be necessary.

Advantages:
- Preservation of pulp vitality.
- Reduced need for root canal treatment.
- Faster healing and less post-operative sensitivity.
- Conservative approach, maintaining more natural tooth structure.

Disadvantages:
- Limited success in deep or prolonged exposures.
- Higher risk of failure in certain cases, such as extensive caries or pulp exposure.
- Requires careful technique to avoid further pulp damage.

Bacterial portals to pulp: caries (most common source), exposed dentinal tubules (tubule permeability ↓ by dentinal fluid, live odontoblastic processes, tertiary and peritubular dentin)

1.        Vital pulp is very resistant to microbial invasion but necrotic pulps are rapidly colonized

2.        Rarely does periodontal disease → pulp necrosis

3.        Anachoresis: microbes carried in blood to area of inflammation where they establish infection

Caries → pulp disease: infecting bacteria are immobile, carried to pulp by binary fission, dentinal fluid movement

1.        Smooth surface and pit and fissure caries: S. mutans (important in early caries) and S. sobrinus

2.        Root caries: Actinomyces spp.

3.        Mostly anaerobes in deep caries. 

4.        Once pulp exposed by caries, many opportunists enter (e.g., yeast, viruses) → polymicrobial infection

Pulp reaction to bacteria: non-specific inflammation and specific immunologic reactions

1.        Initially inflammation is a chronic cellular response (lymphocytes, plasma cells, macrophages) → formation of peritubular dentin (↓ permeability of tubules) and often tertiary dentin (irregular, less tubular, barrier)

2.        Carious pulp exposure → acute inflammation (PMN infiltration → abscess formation).  Pulp may remain inflamed for a long time or become necrotic (depends on virulence, host response, circulation, drainage, etc.)

Endodontic infections: most commonly Prevotella nigrescens; also many Prevotella & Porphyromonas sp.

1.        Actinomyces and Propionibacterium species can persist in periradicular tissues in presence of chronic inflammation; they respond to RCT but need surgery or abx to resolve infection

2.        Streptococcus faecalis is commonly found in root canals requiring retreatment due to persistent inflammation

Root canal ecosystem: lack of circulation in pulp → compromised host defense

1.        Favors growth of anaerobes that metabolize peptides and amino acids rather than carbohydrates

2.        Bacteriocins: antibiotic-like proteins made by one species of bacteria that inhibit growth of another species

Virulence factors: fimbriae, capsules, enzymes (neutralize Ig and complement), polyamines (↑ # in infected canals)

1.        LPS: G(-), → periradicular pathosis; when released from cell wall = endotoxin (can diffuse across dentin)

2.        Extracellular vesicles: may → hemagglutination, hemolysis, bacterial adhesion, proteolysis

3.        Short-chain fatty acids: affect PMN chemotaxis, degranulation, etc.; butyric acid → IL-1 production (→ bone resorption and periradicular pathosis)

Pathosis and treatment:

1.        Acute apical periodontitis (AAP): pulpal inflammation extends to periradicular tissues; initial response

2.        Chronic apical periodontitis (CAP): can be asymptomatic (controversial whether bacteria can colonize)

3.        Acute apical abscess (AAA), phoenix abscesses (acute exacerbation of CAP), and suppurative apical periodontitis: all characterized by many PMNs, necrotic tissue, and bacteria

Treatment of endodontic infections: must remove reservoir of infection by thorough debridement

1.        Debridement: removal of substrates that support microorganisms; use sodium hypochlorite (NaOCl) to irrigate canals (dissolves some organic debris in areas that can’t be reached by instruments); creates smear layer

2.        Intracanal medication: recommend calcium hydroxide (greatest antimicrobial effect between appointments) inserted into pulp chamber then driven into canals (lentulo spiral, plugger, or counterclockwise rotation of files) and covered with sterile cotton pellet and temporary restoration (at least 3mm thick)

3.        Drainage: for severe infections to ↓ pressure (improve circulation), release bacteria and products; consider abx

4.        Culturing: rarely needed but if so, sterilize tissue with chlorhexidine and obtain submucosal sample via aspiration with a 16- to 20-gauge needle

In endodontics, dental trauma often results in the luxation of teeth, which is the displacement of a tooth from its normal position in the alveolus (the bone socket that holds the tooth). There are several types of luxation injuries, each with different endodontic implications. Here are the main types of dental luxation:

1. Concussion: A tooth is injured but not displaced from its socket. The periodontal ligament (PDL) is compressed and may experience hemorrhage. The tooth is usually not loose and does not require repositioning. However, it can be tender to percussion and may exhibit some mobility. The pulp may remain vital, but it can become inflamed or necrotic due to the trauma.

2. Subluxation: The tooth is partially displaced but remains in the socket. It shows increased mobility in all directions but can be repositioned with minimal resistance. The PDL is stretched and may be damaged, leading to pulpal and periodontal issues. Endodontic treatment is often not necessary unless symptoms of pulp damage arise.

3. Lateral luxation: The tooth is displaced in a horizontal direction and may be pushed towards the adjacent teeth. The PDL is stretched and possibly torn. The tooth may be pushed out of alignment or into an incorrect position in the arch. Prompt repositioning and splinting are crucial. The pulp can be injured, and the likelihood of endodontic treatment may increase.

4. Intrusion: The tooth is pushed into the alveolar bone, either partially or completely. This can cause significant damage to the PDL and the surrounding bone tissue. The tooth may appear shorter than its neighbors. The pulp is often traumatized and can die if not treated quickly. Endodontic treatment is usually required after repositioning and stabilization.

5. Extrusion: The tooth is partially displaced out of its socket. The PDL is stretched and sometimes torn. The tooth appears longer than its neighbors. The pulp is frequently exposed, which increases the risk of infection and necrosis. Repositioning and endodontic treatment are typically necessary.

6. Avulsion: The tooth is completely knocked out of its socket. The PDL is completely severed, and the tooth may have associated soft tissue injuries. Time is of the essence in these cases. If the tooth can be replanted within 30 minutes and properly managed, the chances of saving the pulp are higher. Endodontic treatment is usually needed, with the possibility of a root canal or revascularization.

7. Inverse luxation: This is a rare type of luxation where the tooth is displaced upwards into the alveolar bone. The tooth is pushed into the bone, which can cause severe damage to the PDL and surrounding tissues. Endodontic treatment is often necessary.

8. Dystopia: Although not a true luxation, it's worth mentioning that a tooth can be displaced during eruption. This can cause the tooth to emerge in an abnormal position. Endodontic treatment may be necessary if the tooth does not respond to orthodontic treatment or if the displacement causes pain or infection.

The endodontic management of luxated teeth varies depending on the severity of the injury and the condition of the pulp. Treatments can range from simple monitoring to root canal therapy, apicoectomy, or even tooth extraction in severe cases. The goal is always to preserve the tooth and prevent further complications.

Condensing osteitis is a diffuse radiopaque lesion believed to represent a localized bony reaction to a low-grade inflammatory stimulus, usually seen at the apex of a tooth in which there has been a long-standing pulpal pathosis.

Causes

Condensing osteitis is a mild irritation from pulpal disease that stimulates osteoblastic activity in the alveolar bone.

Symptoms

This disorder is usually asymptomatic. It is discovered during routine radiographic examination.

Diagnosis

The diagnosis is made from radiographs. Condensing osteitis appears in radiographs as a localized area of radio opacity surrounding the affected root. It is an area of dense bone with reduced trabecular pattern. The mandibular posterior teeth are most frequently affected.

Histopathology

Microscopically, condensing osteitis appears as an area of dense bone with reduced trabecular borders lined with osteoblasts. Chronic inflammatory cells, plasma cells, and lymphocytes are seen in the scant bone marrow.

Treatment

Removal of the irritant stimulus is recommended. Endodontic treatment should be initiated if signs and symptoms of irreversible pulpitis are diagnosed.

Prognosis

The prognosis for long-term retention of the tooth is excellent if root canal therapy is performed and if the tooth is restored satisfactory. Lesions of condensing osteitis may persist after endodontic treatment.

The Ca(OH)2, has been used by endodontists throughout the world since Hermann introduced it to dentistry in 1920.

It is a highly alkaline substance with a pH of approximately 12.5.

Calcium hydroxide has antibacterial properties and has the ability to induce repair and stimulate hard-tissue formation. The

bactericidal effects is conferred by its highly alkaline pH. The release of hydroxyl ions in an aqueous environment is related to the

antimicrobial property.

Hydroxyl ions are highly oxidizing free radicals that destroy bacteria by :

· Damaging the cytoplasmic membrane

· Protein denaturation

· Damaging bacterial DNA

The vehicle used to mix Ca(OH)2 and the manner in which it is dispensed has a significant role to play in achieving maximum

antibacterial effects as an intracanal medicament in endodontics.

In general, aqueous viscous or oily vehicles are used. The aqueous or water-soluble vehicles have high degree of solubility and

need multiple dressings to achieve desired results.

On the other hand, viscous vehicles like glycerine, polyethylene glycol, and propylene glycol promote slow solubility and hence

longer dressing intervals. The other medicaments combined with Ca(OH)2 include CMCP and 0.12% chlorhexidine.

I. VASCULAR VITALITY ASSESSMENT OF PULP

Traditional vitality assessment methods such as heat, cold, and electric pulp testers assess neural vitality and often cause false-positive errors. As the histological assessment of pulpal status is not feasible clinically, a tool to assess the vascular flow of the pulp would be very useful.

Laser Doppler flowmetry (LDF) is an accurate method to assess the blood flow in a microvascular system

II. PULP CAPPING AND PULPOTOMY

Pulp capping and pulpotomy constitute a more conservative form of pulp therapy in comparison to pulpectomy. Although the outcome of pulp capping procedure is variable ranging from 44 to 97%, the procedure is recommended when the exposure is 1.0 mm or less and especially when the patient is young. Pulpotomy is recommended in immature permanent teeth, where pulpectomy is not advised.

The most commonly used agents for both the procedures are calcium hydroxide and MTA (mineral trioxide aggregate). The use of a laser in these procedures leads to a potentially bloodless field as the laser has the ability to coagulate and seal small blood vessels. The laser-tissue interactions make the treated wound surface sterile and also improve the prognosis of the procedure.

III. DISINFECTION OF ROOT CANALS

The ability of bacterial pathogens to persist after shaping and cleaning is one of the main reasons for endodontic failures. This is attributed to the complex nature of the root canal system, the presence of a smear layer, and the fact that large areas (over 35%) of the canal surface area remain unchanged following instrumentation with various Ni-Ti techniques.

IV. OBTURATION

Thermoplasticized gutta-percha obturation systems are one of the most efficient methods is achieving a fluid-impervious seal. Softening of the gutta-percha has been attempted with various lasers. These include argon, CO , Nd:YAG, and Er:YAG.

V.APICAL SURGERY

Apical surgery including apical resection is indicated when the previously performed root canal therapy fails and nonsurgical means are inadequate to ensure the complete removal of the pathological process.

The potential for using lasers is on the basis of the following observations:
• Ability of lasers to coagulate and seal small blood vessels, thereby enabling a bloodless surgical field
• Sterilization of the surgical site
• Potential of lasers (Er:YAG) to cut hard dental tissues without causing elaborate thermal damage to the adjoining tissues .