Dowel space preparation and the apical seal

Abstract

Seventy maxillary central incisors were tested to determine if two different methods of dowel space preparation had any effect on the apical seal. The teeth were obturated with either thermoplasticized or laterally condensed gutta-percha. Immediately following root canal obturation, dowel spaces were prepared utilizing heated endodontic pluggers or Gates Glidden drills. After the root canal sealer was allowed to set, the teeth were centrifuged in India ink. The teeth were then decalcified in a 20% formic acid solution and dehydrated in alcohol. The teeth were cleared in methyl benzoate. This allowed for direct visual observation of any India ink alongside the gutta-percha root canal filling. A linear measurement of apical leakage was recorded for each tooth. Statistical analysis of the data included an analysis of variance and a multiple range test (Scheffe procedure). Analysis confirmed that no significant difference existed between teeth whose root canals were filled with thermoplasticized or laterally condensed gutta-percha. Dowel spaces prepared with heated instruments were not significantly different in their effect on the apical seal from those prepared with Gates Glidden drills.