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is the most important variable influencing a positive outcome with non-surgical and surgical retreatment (27-29) . Positive treat- ment outcomes may be more likely in certain teeth with a combination of both procedures rather than with one or the other alone (Fig 6). The premise that non-sur- gical retreatment improves the outcome of periapical surgery has been supported by both his- torical and current studies (30-32) . Apical surgical “correction” of intracanal infections may iso- late, but not eliminate, the re- sidual microflora of the root ca- nal space. It should therefore be limited to situations where non- surgical retreatment is judged impractical. With the range of sophisti- cated equipment and material in the conventional endodontic armamentarium, this is a remote consideration at best. When the etiology is independent of the root canal system, surgery is the most beneficial treatment (33) . Non-surgical retreatment may still be indicated in these cases, especially when intracanal in- fection cannot be ruled out. Time constraints or financial pres- sures, should never be a factor in making surgery the first treat- ment choice (Fig 7). Other options The variables associated with non-surgical retreatment are myriad and treatment outcome studies in endodontics have been egregiously abused by those wishing to diminish the value of re-engineering natural teeth. Many studies have categorised teeth with caries, fractures, peri- odontal involvement and poor coronal restorations as negative endodontic outcomes (34, 35) . Prior procedural errors (36), occlusal considerations (37) , ma- terial choice for the restoration (38) and design of the full coverage component all suggest that suc- cess is a function of comprehen- sive treatment planning as much as technical expertise. Evidence based or controlled best evi- dence studies should conclude that these are non-endodontic causes of failure and that the success of endodontic treatment itself is high and predictable. Kvist and Reit (39) have shown that while surgical cases may demonstrate higher healing rates than non-surgical retreatment cases initially, four years out there was no difference between the two modalities due to “late” surgical failure. The failure rate for surgical therapy appears to be analogous to the failure rate for retreatment as a function of the size of the lesion treated (40) . Levels of apical resection (41) and the type of root end fill- ing material make a difference in surgical treatment outcome success (42) ; however, the dentin bonded composite technique and the use of compomer materials has not been widely reported. As these techniques dome the resected root face, sealing off the cut tubuli, they may prove to be the most effective retrograde sur- gical protocols of all. In regard to periapical re-surgery, the litera- ture is unclear. Gagliani et al. (43) compared periapical surgery and re-sur- gery over a five-year follow-up period. Using magnification and microsurgical root-end prepara- tions, the positive outcome for primary surgery was 86 per cent and 59 per cent for resurgery. While others have shown posi-Fig 4. A) Less porous, less hydrated and highly mineralised outer dentine. B) Pulp canal space. C) More porous, more hydrated and less mineralised inner dentin. D) Water in the dentinal tubules and pulp space is held in a confined environment under hydrostatic pressure. Fig 5. Primary causes of fracture include excessive structure loss, loss of free unbound water from the root canal lumen and dentinal tubuli, age induced changes in the dentin and restorations and restorative procedures. Secondary causes of fracture include the effects of endodontic irrigants and medicaments on dentin, the effects of bacterial interaction with dentin substrate and bio-corrosion of metallic post-cores. 25ClinicalAugust 2-8, 2010United Kingdom Edition “Give me something that works fast and I might be interested” Patient, UK References: 1. Mason S et al. J Clin Dent 2010; 21 [Spec Iss]: 42-48. 2. Hughes N et al. J Clin Dent 2010; 21 [Spec Iss]: 49-55. 3. Banfield N and Addy M. J Clin Periodontol 2004; 31: 325–335. 4. Parkinson C and Willson R. J Clin Dent 2010. Accepted for publication. SENSODYNE and THE RINGS DEVICE are registered trade marks of the GlaxoSmithKline group of companies. 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Unoccluded dentine After treatment and a 30 second acid challenge After treatment and a 10 minute acid challenge *when directly applied with finger tip for one minute **when used twice daily The strontium acetate formulation of Sensodyne Rapid Relief forms a deep occlusive plug within the dentinal tubules3,4 providing: • Clinically proven relief.1,2 Works in 60 seconds*1 • Proven long-lasting relief with twice daily brushing2 • A deep, acid-resistant occlusion3,4 • Fluoride to strengthen tooth enamel SM1818_9 Rapid Relief Press Ad 2010 - Dental Tribune 2.indd 1 27/07/2010 15:16