Effect of different machine driven instrumentation techniques on the original root canal anatomy of the first maxillary molars

Abstract

The idea for this study emerged from everyday problems that practitioners are faced in their clinical work during endodontic therapy of teeth with complex root canal anatomy, and due to a lack of information and sufficient data from the literature about influence of machine driven instrumentation techniques on the original anatomy of the root canal system of first maxillary molars. Crucial aim of this dissertation followed the idea of the study, and upon that fact the major tasks were given in order to choose relevant group of maxillary first molars: A) teeth with three distinctive roots and with canal configuration of Vertucci type IV in the mesiobuccal root, and B) teeth with fused roots. Detailed evaluation of several parameters that will define changes of anatomical details were conducted before and after root canal preparation with five machine driven instrumentation techniques: ProTaper Next, Revo-S, WaveOne, Tilos and Self Adjusting File (SAF). With the aid of Cone Beam Computed Tomography (CBCT), introduced in endodontics in the last decade, at the distance of 1.0 mm and 0.1 mm along each root canal the following measurements were conducted: canal walls thickness, dimensions of root canal diameters measured from two directions, and surface area of the root canal cross sections before and after mechanical preparation. The influence, mode of effects and differences of those effects between applied machine driven techniques on the original anatomy of root canals in first maxillary molars were analyzed using appropriate statistical methods. Results of the studies of the anatomical features of two groups of maxillary first molars showed that all dimensions of the tooth crown measured at the level of the pulp chamber floor were significantly greater in teeth with three distinctive roots than in those with fused roots. It was also shown that distances between centers of the canal orifices were significantly different between the two groups of maxillary first molars. These results are of great clinical importance, and with no similar findings in available endodontic literature. Changes in the root canal diameters after mechanical preparation were least in the apical third, and significantly greater at the orifice and in the coronal third of all root canals irrespective to the instrumentation technique. Degree of changes in dimensions of canal diameter was different between the group with three distinctive roots and group with fused roots...

Ideja za istraživanje proizašla je iz problematike sa kojom se susreću terapeuti u kliničkom radu tokom endodontske preparacije zuba sa komplikovanim kanalnim sistemima i nedostataka literaturinih podataka o uticaju mašinskih tehnika instrumentacije na originalnu anatomiju kanalnog sistema prvih maksilarnih molara. Osnovni cilj ove disertacije je pratio ideju istraživanja, na osnovu čega su postavljeni i konkretni zadaci, koji su rukovodili odabir relevantnih grupa prvih maksilarnih molara: I – zubi sa tri odvojena korena i morfološkim tipom Vertucci IV kanala u mezio-bukalnom korenu i II – zubi sa fuzionisanim korenovima. Na njima su sprovedena proučavanja parametara koji će definisati promene anatomskih detalja pre i posle instrumentacije kanala korena koristeći pet specifičnih sistema mašinske obrade: ProTaper Next, Revo-S, WaveOne, Tilos i Self Adjusting File (SAF). Koristeći kompjuterizovanu tomografiju konusnog zraka (CBCT), uvedenu u endodonciju pre nepune decenije, na rastojanju od 1,0 i 0,1 mm duž svakog kanala merene su: debljine zidova korenskih kanala, dimenzije prečnika kanala iz dva osnovna pravca i površine poprečnih preseka kanala pre i posle mašinske preparacije. Statističkim metodima analizirano je da li i na koji način primenjeni sistemi za mašinsku preparaciju utiču na originalnu anatomiju prvih maksilarnih molara i da li između njih postoje razlike. Rezultati antomskih karaktersitika dve grupe prvih maksilarnih molara pokazali su da su sve dimenzije krunice zuba na nivou dna krunične komore veće u grupi sa tri odvojena nego u grupi sa fuzionisanim korenovima. Takođe je pokazano da su rastojanja između cenatara ulaza u korenske kanale statistički zančajno različite između ove dve grupe prvih maksilarnih molara, što je od izuzetnog kliničkog značaja, a bez sličnih nalaza u dostupnoj literaturi. Promene dimenzije prečnika kanala posle preparacije su bile najmanje u njihovoj apeksnoj trećini, a statistički značajno veće na ulazu i u koronarnoj trećini kanala. Stepen promena dimenzija prečnika razlikovao se između grupe sa tri odvojena i grupe sa fuzionisanim korenovima. U obe grupe zuba su najizrazitije promene vrednosti prečnika kanala bile na njihovom ulazu, a najmanje u apeksnoj trećini, i to posle primene svih pet tehnika instrumentacije...