ABSTRACT
Statement of the Problem: There are some concerns regarding the effect of Chlorhexidine [CHX] applied for cavity disinfection on the bond strength of adhesive restorations to dentin
Purpose: This study sought to assess the effect of CHX on the shear strength [SBS] of Equia resin-modified glass ionomer cement [RMGIC] to dentin in permanent teeth
Materials and Method: In this experimental study, the buccal surface of 84 freshly extracted human premolars was ground to expose the flat dentin. The samples were randomly assigned to four groups [n=21]. The steps were as following in the group I[a]: conditioning, Equia RMGIC, 500 thermal cycles; group Ib: conditioning, Equia RMGIC, 6000 thermal cycles; group II[a]: conditioning, CHX, Equia RMGIC, 500 thermal cycles, and group II[b]: conditioning, CHX, Equia RMGIC, and 6000 thermal cycles. Twenty samples from each group were subjected to SBS test and one sample was inspected under a scanning electron microscope. Data were analyzed using two-way ANOVA and t-test
Results: The SBS was significantly different among the groups [p= 0.007]. The groups subjected to 500 thermal cycles showed significantly higher SBS to dentin when they were treated with CHX [p= 0.000]. There was no significant difference between samples thermocycled for 6000 cycles with and without application of CHX [p= 0.269]
The SBS in the groups that were thermocycled for 6000 cycles [I[b] and II[b]] was lower than those thermocycled for 500 cycles [I[a] and II[a]]. This difference between II[a] and lib was statistically significant [p= 0.007]
Conclusion: Chlorhexidine can positively affect the short term SBS of Equia RMGIC to dentin
Subject(s)
Disinfectants , Disinfection , Shear Strength , Glass Ionomer Cements , Dentition, PermanentABSTRACT
Background and Aim: Detection of Horizontal root fracture is completely related to radiography and application of new methods is indispensable .The aim of this study was to compare the diagnostic accuracy of reverse contrast option of digital radiography with original images for detection of horizontal root fracture
Materials and methods: In this diagnostic study, digital radiographs were taken from 40 maxillary anterior teeth mounted in a dry alveolar socket with vertical angles of 0[degree sign]and 15 [degree sign] .Root fractures were created in the horizontal plane on each root and after relocating root fragments radiographs were repeated in a same position. Images were processed with reverse contrast option and assessed by observers. Data were analyzed with proportion test and Cochran's Q test
Results: There was no significant difference in sensitivity, specificity, PPV[Positive Predictive value] and NPV [Negative Predictive Value] between 0[degree sign]and 15[degree sign]radiographs in original and reverse contrast images. In either image groups, when fractures were certainly diagnosed by observers, 0[degree sign]radiographs obtained higher sensitivities [P=0.014] Also when fractures were likely diagnosed , sensitivity and NPV were significantly higher for 0[degree sign]radiographs [P=0.035] ,[P=0.023]respectively
Conclusion: The diagnostic accuracy of reverse contrast option of digital images are equal to original images, although 0[degree sign]radiographs are more appropriate