ROEN0110

10 I I special _ endo-implant algorithm roottrunkperiphery,whichassistsindiscoveryofthe spatial orientation and morphology of the roots. The pulp chamber ceiling and pulp stones can be peeled away with a football diamond bur to identify grossly the primary orifices. Micro-etching (Danville Materials) the floor of the chamber, perhaps the most underused of all access tools, is invaluable in the exposure of fusion lines and groovesinordertoidentifyaccessoryorifices.Trough- ing with ultrasonic tips of any design is used solely to trace fusion lines, not affect gross removal. The use of ultrasonics to ‘jackhammer’ pulp stones is simply too risky as one approaches the floor of the chamber, par- ticularly if there are no water ports on the tips. Orifice lengthening and widening enables straight-line glide pathtotheapicalthird.Thestrategicobjectiveisnotto impede the file, stainless-steel or NiTi rotary along the axialwallswithminimaldentineremoval(Figs.8a&b). It is equally important to produce a high-quality coronal restoration at the time of sealing the root- canal system.21,22 Despite research supporting the effectiveness of coronal barriers and the need for immediate placement as a component of the com- pletion phase of root-canal treatment, a universally accepted protocol does not exist. SchwartzandFransmandescribedaclinicalstrat- egy for coronal sealing of the endodontic access preparationthatliststhefollowingconsiderationsin the protocol: use bonded materials (4th generation (three-step)resinadhesivesystemsarepreferredbe- cause they provide a better bond than the adhesives that require fewer steps); the etch and rinse adhe- sives are preferred to self-etching adhesive systems, ifaeugenol-containingsealerortemporarymaterial is used; self-etching adhesives should not be used with self-cure or dual-cure restorative composites. When restoring access cavities, the best aesthetics and highest initial strength are obtained with an incremental fill technique using composite resin. A more efficient technique that provides acceptable aestheticsistobulkfillwithaglassionomermaterial to within 2 to 3mm of the cavo-surface margin, fol- lowed by two increments of light-cure composite and, if retention of a crown or bridge abutment is a concern after root-canal treatment, post placement increasesretentiontogreaterthantheoriginalstate (Fig. 9).23 _Irrigation The complex anatomy of the root-canal space presents a daunting challenge to the clinician who must thoroughly debride and disinfect the corridors of sepsis in order to achieve a successful treatment outcome (Fig. 10). In addition, the absence of a cell- mediated defence (phagocytosis, a functional host response) in necrotic teeth means the micro-or- ganisms residual in tubuli, cul-de-sacs and arbori- sations are mainly affected by the redox potential (reduction potential reflects the oxidation—reduc- tion state of the environment—aerobic microflora can only be active at a positive Eh, whereas strict anaerobes can only be active at negative Eh values) and availability of nutrients in the various parts of the root canal.24 Whileourknowledgeofpersistentbacteria,disin- fectingagentsandthechemicalmilieuofthenecrotic root canal has greatly increased, more innovative basic and clinical research is required in order to Figs. 5a & b_Flat-field sensors provide a sense of the extent of osseous pathology; however, the peri-apical radiographic image corresponds to a 2-D aspect of a 3-D structure. Peri-apical lesions confined within the cancellous bone are usually not detected. Thus, a lesion of a certain size can be detected in a region covered by a thin cortex, whereas the same size lesion cannot be detected in a region covered by thicker cortex. Tables I & II_Derived from Baumgartner (Antibiotics and the Treatment of Endodontic Infections, Summer 2006). roots1_2010 Table I Table II Indications for adjunctive antibiotics Conditionsnotrequiringadjunctiveantibiotics Fever > 100°F Pain w/o signs and symptoms of infection Malaise Symptomatic irreversible pulpitis Lymphadenopathy Acute periradicular periodontitis Truismus Teeth with negrotic pulps and radiolucency Increased swelling Teethwithasinustract(chronicperiradicularabsess) Cellulitis Localised fluctuant swellings Osteomyelitis Fig. 5a Fig. 5b

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