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Dental Tribune Indian Edition

4 Dental Tribune Indian Edition - January 2013 may be a fundamental contributor to post-treatment disease. The following case illustrates the ability to overcome prior incomplete treatment to achieve successful healing (Figs 3a–c). Clinical example Restorative failure is a common cau- se of post-treatment disease. Failure to place an effective permanent access re- storation in a timely manner can allow for bacterial entry into the root-canal system by coronal leakage. Submar- ginal leakage on a crowned tooth can also allow bacterial entry to occur. Decay in a previously treated to- oth is another source of bacterial contamination. Structural damage to a tooth by trauma, cracking or frac- ture may provide an entry point for bacterial contamination of the canals. Our patients are responsible for their own oral health and must commit to effective oral hygiene techniques. Fai- lure of the patient to perform effective oral hygiene can result in the failure of even the most well-executed root- canal and restorative treatments. With the bacterial challenges clini- cians have to face, retreatment tech- niques must be capable of effective elimination of bacteria and their sub- strates. The use of a dental operating microscope and ultrasonic instru- ments allows clinicians to uncover all existing canal anatomy properly to ensure that they are able to cleanse the root-canal system completely. The following clinical case (Figs 4a & b) illustrates the extent of the canal space left untreated in the initial root-canal therapy by not opening the mesiobuc- cal canal adequately and not locating and cleansing the hidden second me- siobuccal canal. Endodontic ultrasonic tips are hi- ghly efficient at removing core bu- ild-up material, paste fills, posts and silver-point fillings, as demonstrated in Figure 5. These instruments allow clinicians to conserve root dentine by providing excellent visibility under a dental operating microscope, thereby greatly improving the ability to retre- at canals (Figs 6a–c). A heat source such as a System B tip (Axis, Sybro- nEndo) is efficient for the removal of gutta-percha and resin materials from the coronal third. Hand and ro- tary files can remove root fillings and shape canals to appropriate working lengths. Current NiTi rotary files are highly flexible and resistant to sepa- ration and allow us to mechanically enlarge the apical third of root canals safely and efficiently without altera- tion of the natural canal morphology, which allows effective irrigation to reach the complex apical root-canal anatomy where bacteria are able to hide and resist debridement. Once the canals have been located and instrumented, the ability to irri- gate becomes essential to successful treatment. The irrigant solutions tar- get the bacteria we are trying to eli- minate. While sodium hypochlorite is a potent and proven antimicrobial and tissue dissolver,22 2% chlorhexidine has been shown to prevent the adhe- sion of E. faecalis to dentine.23 EDTA 17% is often used as an effective sme- ar layer removal agent.24 Therefore, mechanical debridement and canal instrumentation provide a pathway for copious chemical irrigation deep into the canal. Passive ultrasonic irrigation allows clinicians to place an irrigant solution into the pulp chamber and activate it as it is carried down to the apical end of the root canal. The IrriSafe tip from Satelec (Acteon; Fig 7) is a non- cutting ultrasonic file that is placed into each canal and is moved up and down in the canal for three cycles of 20 seconds. Passive ultrasonic irriga- tion has been shown to irrigate lateral canals better at 4.5 and 2 mm from the working length of canals as com- pared with needle irrigation alone.25 It has been demonstrated that passive ultrasonic irrigation can remove den- tine debris in a canal up to 3 mm in front of where the tip extends apical- ly in straight or curved canals.26 This evidence shows that an effective flow of irrigation can assist in the clean- sing of teeth in which canal alteration occurred during the initial root-canal treatment. The following silver-point case (Figs 8a–c), with a large distal post and api- cal transportation in the mesial root, demonstrates the successful healing of post-treatment disease when proper disinfection has been accomplished. This case illustrates the reason that retreatment is the primary treatment option for post-treatment disease. Once debridement and disinfection have been completed, appropriate obturation methods are used to seal the canal spaces. The warm vertical technique using gutta-percha or resin with an appropriate sealing agent pro- vides a thorough seal of the well-cle- ansed and shaped canal spaces. The final restoration must provide a proper seal of the pulp chamber to prevent coronal micro-leakage. Current evidence has demonstrated that we can retreat previously endo- dontically treated teeth properly and successfully. The literature has also shown that specific bacteria, such as E. faecalis, are able to survive inside a previously filled canal. The use of a dental operating microscope, ultra- sonic instruments, irrigants, rotary NiTi files and appropriate obtura- tion materials increases our ability to attain healing after retreatment. As we continue to strive to maintain healthy natural teeth for our patients, endodontic retreatment should be the primary option for patients with post- treatment disease. A complete list of references is available from the publisher.DT Fig. 7: IrriSafe tip from Satelec. (Courtesy of Acteon Group, France)—Fig. 8a: Tooth #30 with silver-point fillings in the mesial root and a post in the distal root. The mesial root-canal preparations are transported towards the mesial. There is a radiolucent periapical lesion.—Fig. 8b: Post-op radiograph.—Fig. 8c: Fifteen-month follow-up. (Courtesy of Dr Brett E Gilbert) Fig 7 Fig 8a Fig 8b Fig 8c Dr Brett E Gilbert has a full-time private practi- ce specialising in endo- dontics in Niles, Illinois, USA. He also lectures nationally and internationally on clini- cal endodontics. He can be contacted at kingendo@kingendo.com. Contact Info Trends & Applications Fig. 3a: Tooth #30 with a radiolucent periapical lesion with evidence of incomplete cleansing, shaping and obturation.—Fig. 3b: Post-op radiograph.—Fig. 3c: Thirteen-month follow-up radiograph. (Courtesy of Dr Brett E Gilbert)—Fig. 4a: Tooth #3 with a radiolucent periapical lesion on the mesiobuccal root apex.—Fig. 4b: Post-op radiograph showing treatment of the second mesiobuccal canal and appropriate lengths on retreatment of the distobuccal and palatal canals. (Courtesy of Dr Brett E Gilbert)—Fig. 5: Photograph displays excellent visibility and magnification of the pulp chamber with the use of an ultrasonic tip. (Courtesy of Dr Scott Bentkover, USA)—Fig. 6a: Tooth #3 with silver-point fillings in the mesial root and a large post in the distal root. A large radiolucent periapical lesion is evident on the distal root.—Fig. 6b: Post-op radiograph.—Fig. 6c: Thirteen-month follow-up radiograph. (Courtesy of Dr Brett E Gilbert) Fig 3a Fig 3b Fig 3c Fig 4a Fig 4b Fig 5 Fig 6a Fig 6b Fig 6c