2. Isolation, Access, Length determination.pdf

Isolation, Endodontic Access, and Length Determination Isolation advantages • Enhances visibility • Protection for the patient and creates an aseptic environment • Protects from laceration from rotary instruments, chemical agents, and medicaments. • Irrigating solutions are confined to the operating...

Isolation, Endodontic Access, and Length Determination Isolation advantages • Enhances visibility • Protection for the patient and creates an aseptic environment • Protects from laceration from rotary instruments, chemical agents, and medicaments. • Irrigating solutions are confined to the operating field • Protects the patient from swallowing or aspirating instruments and materials • Reduce the potential for transmission of systemic diseases • Barrier against the patient’s saliva and oral bacteria • Significantly increases the tooth survival rates after initial RCT • Mandatory for legal considerations (STANDARD OF CARE!!) • Not using one is an unnecessary risk Dam Components • Latex and Non-Latex RD • Thickness - light, medium, heavy (medium is recommended) • Frames - Metal, Plastic (plastic is recommended b/c it won’t block x-ray) Dam Placement • Place as one unit • Or put the frame on after placement • Or put clamp on and then stretch RD over clamp • When using a non-wing clamp, place RD first then then clamp Preparation for Rubber Dam Placement • May not have much tooth structure to clamp o May need to remove decay and build up to allow proper isolation • May have young pt with only partially erupted tooth • Caulk can be used to fill spaces dam cant reach, such as when isolated around bridges • Sometimes you will have to clamp against gums o Palatal tissue is very tight, placement puts lots of pressure on the tissue and induces pain, hence give Greater palatine nerve anesthetic Access Openings • Based on the anatomy/morphology of each individual tooth group • In general pulp is located at CEJ o Pulp horns more prominent in young teeth, at about the level of height of contour o Morphology of pulp will change with age General Principles for endo access 1. Outline form 2. Convenience form 3. Caries removal 4. Periphery cleaning: Preparation’s periphery is cleaned to ensure no debris or object fall into the canals Outline Form • It is the recommended shape to access preps for a normal tooth w radiographic evidence of pulp chamber, canal space to ensure: • In anterior and premolars - calcifica[on o Correct shape occurs in a coronal to apical direc[on o Location • In posterior teeth with bifurca[ons and o Straight line access to apical canal/first curvature trifurca[ons - secondary den[n is • It is the projection of internal anatomy onto external structure deposited on the floor of the chamber • Can change with time (Pulp chamber can change w age, trauma) • In old age pulp size and number of cells decrease, and fibrous tissue increases o Absent pulp horns o Access is ovoid • Attrition affects pulp horns, appearing as dead tracts and sclerotic dentin • Normally, anterior teeth have mesial and distal pulp horns- triangular access Convenience Form • Allows modification of ideal outline form • Facilitates unstrained instrument placement and manipulation Ex. Nickel-titanium rotary instruments require straight-line access Caries Removal • Essential for: o The development of an aseptic environment prior to entering pulp chamber/radicular space o Assesses for restorability before tx o Provides sound tooth structure for placement of adequate provisional restorations (coronal seal) Cleaning the Periphery • Involves preventing materials, objects from entering the chamber and canal space • Common error is entering the pulp chamber before the coronal structure or restorative materials have been adequately prepared. • As a result, these materials enter canal space and block apical portion of the canal. Canal Morphologies • 5 major canal morphologies: o Round o Ribbon/figure-eight o Ovoid o Bowling Pin o Kidney bean o C-shape (Common in lower molars- Asian population) General Considerations • Access can be done w/o the placement of a rubber dam • Rubber dam MUST BE PLACED before files and broaches are used • Assess pre-op images to determine case difficulty • Depth of access calculated • X-rays are encouraged to ensure correct orientation after start of access • High speed fissure burs best for access opening • Sharp endo explorer used to detect canal orifice or dislodge calcifications • A tipped tooth may be ‘up righted’ or a rotated tooth ‘realigned’ • One canal can be used as a reference point for finding the others o Files can be inserted and an angled image taken to reveal what canal has been found o Complex restorations (ex. crowns, fixed partial dentures) can change coronal landmarks used in canal location • Access through crowns w extensive foundations can hinder visibility o Ceramic crown penetration via high speed round diamond w water coolant o Then, switch to fissure bur once dentin has been penetrated o All ceramic/zirconia crowns has special burs to assist in gaining access thru these materials