The following is an excerpt from #vanendo lecture series at this year’s Pacific Dental Conference.
The apical 3mm of an infected root canal system is considered to be the “Critical Zone” when it comes to the chemomechanical preparation. Mechanical instrumentation and chemical disinfection of the root canal system to its full length significantly affect the outcome of treatment. All endodontists agree that the irrigation phase of the root canal treatment must be accompanied by an agitation technique. These techniques include: sonic agitation (EndoActivator), ultrasonic agitation, multi-sonic agitation (promising area of research currently), and the cheapest and simplest of all, Manual Dynamic Agitation (MDA).
The following video demonstrates how the MDA technique (repeated insertion of a well-fitting gutta-percha cone to the WL at a frequency of 100 strokes/min) significantly facilitates debris removal from the apical portion of a root canal system that appears to be fully shaped and cleaned.
Office website: vanendo , FaceBook page: @endospecialists
It is known that micro-organisms in irregular spaces beside the main canals and specially in lateral and accessory canals survive the limited effect of chemomechanical instrumentation. There are overwhelming amount of evidence in endodontic literature in support of the short-term use of CaOH (a week or longer). It effectively reduces or eliminates bacterial infection from the root canal system. Therefore, it is always beneficial to use an inter-appointment medicament such as calcium hydroxide, specially in non-vital or re-treatment cases.
CaOH is usually made into a paste by mixing with saline. Inside the root canal system, CaOH dissociates into Ca++ and OH- ions resulting in an increased pH (up to 12.5) and an alkaline environment. No micro-organisms survive at this pH and when they come into direct contact with CaOH.
The beneficial effects of CaOH include:
- Prolonged and broad antibacterial action
- Anti-inflammatory action (for example, stopping the exudative stage of inflammation)
- Helping the local immune system
- Enhancing the necrotic tissue dissolution when using in conjunction with NaOCl
- Promoting bone formation and repair (complete repair is expected in 2-3 months)
- Preventing re-infection inside the canal system by virtue of its physical presence
My favourite preparation of calcium hydroxide is UltraCal® XS. UltraCal® XS is an aqueous, 12.5 pH, syringeable, radiopaque, calcium hydroxide paste. Flexible NaviTips are used to deliver CaOH inside the canals. NaviTips are not side-vented needles. So, care should be taken while placing CaOH suing this delivery method. It should be delivered short of the apex (use the rubber stopper as a guide) while slowly withdrawing tips.