Please activate JavaScript!
Please install Adobe Flash Player, click here for download
ePaper created 2016-03-31, 16:35:38 | version 1.38.0
| literature review fibre post restorations 28 roots1 2016 The authors state that ‘although prosthodontic textbooksdonotgenerallyadvocatetheplacementof fibre posts in endodontically treated incisors, the re- sults of this study indicate that the use of fibre posts insuchteethincreasestheirresistancetofractureand improves the prognosis in case of fracture’. In a study of 80 endodontically treated maxillary premolars treated with or without fibre posts, and MOD cavity preparations restored with different types of crowns, including porcelain fused to metal, lithiumdisilicate,fibrereinforcedcompositeorzirco- nia crowns, Salemeh et al,63 loaded the restorations until failure, recording the maximum breaking loads. Under vertical loading conditions, the fracture loads of teeth restored with fibre posts were significantly greater than those without posts, and the fibre posts significantly contributed to the reinforcement and strengtheningofpulplessteethbysupportingthere- mainingtoothstructureagainstverticalcompressive stresses. There are many more studies showing the rein- forcementoftoothstructurewithfibreposts.64–73 Itis impossible to summarise them all, but it seems obvi- ous that our concept of restoring endodontically treated teeth is continually advancing as new prod- uctsandbondingtechniquesevolve.Evenwhenthere are variations in the types of fibre posts used in the studies,anddifferentcementationandadhesivepro- tocols, there is compelling evidence that fibre posts can reinforce tooth structure. To create balance in this overview of the literature, itmustbesaidthatthereareofcoursesomepublished scientificarticlesthatdonotshowareinforcingeffect of fibre posts.7, 74, 75 Inadditiontothetraditionaldefinitionofmechan- icalreinforcement:restoringacompromisedtoothto afracturestrengthequaltoorgreaterthanitsoriginal ‘untreated’ fracture resistance, we clinicians perhaps should be more focused on the predictability of out- comes, particularly in worst-case scenarios. That is the contribution of the post versus no post, or com- positeonly,totheremainingstructures.Themostpre- dominant conclusion emerging from the growing body of in vitro76–79 (and clinical) data is that failures of fibre posts insitu are more likely to be described as ‘non-catastrophic’or‘repairable’,whichisusuallynot the case with high modulus posts. Furthermore, recently published clinical trials cor- relate the success rate to the number of remaining dentine walls.51, 80, 81 Variations in the literature on fi- brepostsaretheresultsof:useofnaturalteethorbo- vine teeth; invivo versus invitro results; the effect of the periodontal ligament in distributing some of the stresses; loading technique (vertical, horizontal or at anangle);thetypeandqualityofthepost;therecog- nition of the ‘secondary smear layer’ and how it af- fectsadhesion;thetypeofradiculardentinethatisto be bonded; the adhesive used; the light carrying or transmission capability of the post; the type of com- posite used to cement the post; the amount of com- Fig.7: The typical result of creating a full crown with a ferrule in a moderately tapered endodontic access opening. Fig.8:When preparing a ferrule on a tooth with a wide flare,the preparation removes all lateral dentine,creating a standalone core,which drastically decreases the clinical success rate. Fig.7 Fig.8