Endodontics: Rotary Instruments, Luxation, and MTA
Endodontic Materials and Procedures
Rotary Instruments: Protaper, K3, and G Pack
- Protaper: SX D0=0.19mm Taper=3.5-19%
- S1: D0=0.17mm Taper=2-11%
- S2: D0=0.20mm Taper=4-11.5%
- F1: D0=0.20mm D0-D3=7%
- F2: D0=0.25mm D0-D3=8%
- F3: D0=0.30 D0-D3=9%
- K3 (2002-McSpadden): Sizes:
- 0.02 taper: #15-45
- 0.04, 0.06: #15-60
- Lengths: 21, 25, 30 mm
Body Shapers
- Tapers: 0.08, 0.10, 0.12
- Tip: #25
- Length: 17, 21, 25mm
G Pack
Design features: Positive rake angle, 3 radial lands, relief on 2, Asymmetrically placed lands, unequal land width, Asymmetric flute depth, width
Ni-Ti Rotary Instruments
Advantages:
- Gradually evenly tapered radicular preparation
- Few instruments required
- Less time
- Use in a handpiece allows better vision
- Less debris extrusion
Disadvantages:
- Narrow canals difficult – instrument fracture
- Fracture occurs without signs
- Expensive
- Dulls quickly
Luxation Injuries
Involves trauma to the supporting tissues of the tooth.
Luxation injuries in increasing order of severity:
Concussion
A minor injury to the periodontal tissue without malposition or mobility of the teeth.
Mechanism:
A frontal impact leads to hemorrhage and edema in the periodontal ligament.
Treatment:
- Relief of occlusal interferences
- Recommendation of soft diet for two weeks
- Monitor pulp response periodically
Subluxation
Results from slight injury to the periodontal tissue with a slight increase in mobility.
Mechanism:
If the impact has greater force, the periodontal ligament fibers may be torn, resulting in loosening of the injured teeth.
Pathogenesis:
Oblique forces displace the tooth out of its socket.
Treatment:
Consists of atraumatic repositioning and fixation.
Extrusive Luxation
Lateral Luxation
An injury involving displacement labially, lingually, distally, or incisally.
Pathogenesis:
Horizontal forces displace the crown palatally and apex labially.
Clinical Features:
Lateral displacement of tooth, sulcular bleeding, sensitivity to percussion.
Treatment:
Local anesthetic administered. Tooth repositioned.
Intrusive Luxation
An injury involving displacement in an apical direction into the alveolus.
Diagnosis and Clinical Presentation:
Tooth pushed into the socket, gives metallic sound to percussion test, infra occlusion.
Treatment:
Depends entirely upon the stage of root development.
Fiber Reinforced Posts
Advantages:
- Esthetics
- Biocompatible
- A cementing procedure that is light, dual, or self-curing can be used
- Higher bond strength
- Metal-free, which does not break down cement
- Higher bond strength of the core material buildup due to similar chemical composition
- Dentin bonding
- Easy removal
- High tensile strength
- High fatigue strength
Disadvantages:
- Micro leakage
- Less strength
- Color of the carbon creates esthetic problems
- Less stiffness
Indications:
- Minimum tooth structure missing
- Uncertain endodontic prognosis of the tooth
Contraindications:
- Tooth under lateral load
Ceramic Posts
Advantages:
- Esthetics
- Good stiffness
- Biocompatible
Disadvantages:
- Uncertain clinical performance
- Difficult to use
- Lack of retention
- Expensive
Rotation vs. Reciprocation in Endodontics
Rotation Advantages:
- Greater tactile touch and efficiency gained
- Requires less inward pressure
- Improves hauling capacity of debris
Rotation Disadvantages:
- Risks associated with torque and cyclic fatigue failures
Reciprocation Advantages:
- Mimics manual movement
- Reduces various risks
Reciprocation Disadvantages:
- Requires multifile sequences
- Decreased cutting efficiency
- More required inward pressure
- Limited capacity to debride canals
Mineral Trioxide Aggregate (MTA)
Advantages:
- High biocompatibility
- Hydrophilic
- Radio-opaque
- Highly alkaline pH (Bacteriostatic)
- Excellent sealing ability
Disadvantages:
- Difficult manipulation
- High cost
- Irreversible application
Analgesics in Dentistry
Opioid Analgesics:
- Act centrally
- Cause addiction
- Produce CNS depression
- Do not produce gastric irritation
Non-Opioid Analgesics:
- Act peripherally
- Do not cause addiction
- No CNS depression
- Produce gastric irritation
Adverse Effects Shared by N-NSAIDs:
- GIT upsets (nausea, vomiting)
- GIT bleeding & ulceration
- Bleeding
- Hypersensitivity reaction
- Inhibition of uterine contraction
Adverse Effects of Opioids:
- Sedation
- Respiratory depression
- Dependence
- Nausea
- Constipation
- Dizziness
Pulp Regeneration
Advantages:
- Apex is not fully developed (blunderbuss shape)
Disadvantages:
- Cleaning and shaping of the apical portion of the root canal system can be difficult
- Complicated by the presence of thin, fragile dentinal walls
- Open apex increases the risk of extruding material into the periradicular tissues