Root surface conditioning in periodontal treatment

Blomlöf J Root surface conditioning, in periodontal treatment. Thesis, Karolinska Institutet. Marginal periodontal healing following both invasive and non-invasive therapiesis influenced by a large number of systemic and local factors. In ordcr to optimizehealing, a lot of effort is put into minimizing possible sources of infection bothin performing different periodontal therapies as well as during the healing period.Mechanical root surface debridement inevitably produces an infected smear layer whichcovers the exposed mineralized root surface. The overall aim of the studies on whichthe present thesis is based, was to characterize how the nature of the root surfacemay modify the qualitv of periodontal healing tissues. The general working hypothesiswas that a smear-free dcntin surface in which collagen has been exposed providesa more biocompatible surface for periodontal healing compared to a mincralizcd andsmear covered root surface. This thesis is based on experimental in vitro (I-V,X),in vivo (II,VI-VIII) and in situ (IX,X) studies. Pre-clinical confirmation of theefficacy of EDTA in removing both smear and exposing collagen on a root surface wasobtained before the beneficial effect of the procedure was established in vivo aswell as its clinical utility. Similarly, previously recommended etching procedureswere studied and their low pH appeared to impair healing as seen both in the initialcellular event in colonization of denuded root surfaccs (II) and in a necrotizingeffect on healthy periodontal tissuee in the vicinity of an experimental periodontalwound (VI). Marginal periodontal healing after several weeks appeared also to sufferfrom etching at low pH while etching at neutral pH appeared not to interfere withspontaneous healing (VII,VTII). The results from the in situ studies indicate thatthe different root surface debridement and etching procedures functioned along thesame principles as observed in vitro with some modifications probably due to influencefrom the surrounding tissues, blood and the nature of the periodontitis affectedroot surfaces (IX,X). Two principally different areas of clinical use for EDTA etchingare evident: Firstly, in conventional non-surgical and surgical periodontal therapy to removesmear in order to minimize post-surgical infection. Secondly, in regenerative procedures to expose an intact collagenous matrix whichmay provide for retention of implants of biologically active substances such as growthfactors in addition to serving as a biocompatible surface for periodontal ligamentcell colonization. Key words: citric acid, collagen, EDTL, etching, monkey, periodontal healing,periodolntitis, phosphoric acid, root planing, scanning electron microscopy, smearlayer, ultrasonic scaling, vitality. ISBN: 91-628-2646-8 de