In vitro evaluation of coronal microleakage associated with two root obturation techniques

Abstract

Aim: The purpose of this study was to determine the influence of the smear layer on the coronal microleakage in root canals obturated with laterally condensed cold gutta-percha or Thermafil and two root canal sealers. Materials and methods: Sixty extracted single-rooted human teeth with straight root canals were allocated to two experimental groups. The root canals were instrumented using the STEP-BACK technique, K reamers and K files and irrigated with 2.5 % NaOCl. The teeth in the first group were treated with 17% EDTA and 2.5 % NaOCl to remove the smear layer. The teeth in both groups were obturated either with laterally condensed cold guttapercha (28 teeth) or Thermafil gutta-percha with plastic cores (28 teeth) and RSA or AH-PLUS sealers. The specimens were evaluated for coronal microleakage using silver nitrate solution. The linear penetration of the dye was assessed using a binocular magnifying glass (x25), with an inserted micrometer scale. Results: The results showed low coronal microleakage in the group where the smear layer was removed in both the lateral compaction technique (RSA - 1.71mm and AHPLUS - 1.61mm) and the Thermafil groups - RSA (1.65mm) and AH-PLUS (1.66mm). In the group with the intact smear layer, greater microleakage was noticed in both groups, lateral compaction technique -RSA (3.06 mm) and AH-PLUS (2.83mm) and Thermafil technique -RSA (2.99mm) and AH-PLUS ( 2.83mm). The difference was statistically significant between the groups with and without the smear layer for both RSA (p lt 0.001) and AH-PLUS sealers ( p lt 0.001). Conclusion: The present results suggest that the removal of the smear layer significantly improves the tightness of the coronal seal and reduces the coronal microleakage.

Cilj: Cilj ovog rada je bio da se proveri uticaj razmaznog sloja na krunično mikopropuštanje kanala opturisanih primenom Termafil i tehnike hemijski razmekšane gutaperke. Materijal i metod: Korišćeno je 60 ekstrahovanih jednokorenih zuba sa pravim kanalima koji su podeljeni u dve eksperimetnalne grupe. Kanali su obrađeni primenom STEP-BACK tehnike i primenom proširivača i turpija tipa K uz obilnu irigaciju 2,5% rastvorom NaOCl. U prvoj grupi kanal je tretiran 17% rastvorom EDTA i 2,5% rastvorom NaOCl radi uklanjanja razmaznog sloja, a uzroci druge grupe su bili sa očuvanim razmaznim slojem. Zubi prve i druge grupe su potom opturisani tehnikom hemijski razmekšane gutaperke (28 zuba) odnosno primenom Termafil tehnike opturacije (28 zuba) primenom pasti RSA RDEKO SEAL i AH-PLUS. Zubi su pripremljeni za proveru krunične mikropropustljivosti potapanjem u rastvor srebro-nitrata. Linearni prodor boje procenjivan je uz pomoć binokularne lupe sa mikrometarskim razmernikom i uvećanjem 25 puta. Rezultati: Dobijeni rezultati su ukazali na manju kruničnu mikropropustljivost u grupi gde je razmazni sloj bio uklonjen i kod tehnike hemijski razmekšane gutaperke (RSA- 1,71mm, AH-PLUS-1,61mm) i primenom Termafil tehnike obturacije (RSA-1,65mm, AH-PLUS-1,66mm). U grupi gde razmazni sloj nije uklonjen uočena je veća mikropropustljivost i primenom tehnike hemijski razmekšane gutaperke (RSA- 3,06mm, AH-PLUS - 2,83mm) i primenom Termafil tehnike (RSA - 2,99, AH-PLUS - 2,83). Razlika je bila statistički značajna između grupa gde je razmazni sloj uklonjen i grupe gde nije uklonjen kod oba testirana materijala na nivou p lt 0,001. Zaključak: Dobijeni rezultati su pokazali da uklanjanje razmaznog sloja značajno poboljšava kvalitet zaptivanja u kruničnom delu i time značajno smanjuje krunično mikropropuštanje.