Effectiveness of Intracanal Calcium Hydroxide Placement: Comparison of Three in vitro Techniques

Calcium hydroxide (CH) is a widely used intracanal medicament due to its antibacterial properties, and its application must be effective to achieve the greatest biological effect. The aim of this study was to compare, using digital radiography, the obturation effectiveness of three CH application techniques. Twenty-seven simulated straight canals were prepared using standardized Mtwo rotary instruments, with a size 40 master apical file and 0.04 taper. The canals were randomly assigned to three groups (n = 9), and each group was obturated with CH paste using one of the following techniques: manual technique (MT), Lentulo spiral technique (LT), and syringe technique (ST). Based on the post-obturation digital radiographs, the quality of the filling was assessed according to two parameters: material density and apical extension of the filling, evaluated by the presence of voids and the apical reach of the material. The results showed that the probability of achieving complete CH density using the ST was 4.5 times higher than with the LT and MT. Likewise, the probability of obtaining full apical extension with the ST was 28 times higher compared with the MT. In conclusion, the ST proved to be the most effective method for applying CH in straight canals, achieving greater mate- rial density and more accurate apical reach.

KEY WORDS: Intracanal medication, calcium hydroxide, application techniques