ABSTRACT
BACKGROUND: The aim of the present study was to evaluate the efficiency of two irrigating techniques - static and dynamic (passive ultrasonic instrumentation) irrigation in the elimination of bacterial biofilm. MATERIALS AND METHODS: Forty extracted human permanent maxillary central incisors teeth with straight roots and single canals, were randomly allocated to two groups for static irrigation and passive ultrasonic irrigation (PUI). The root canal irrigant used was 2.5 % sodium hypochlorite. The root canals were prepared to tip sizes (20, 40) and tapers (0.04, 0.08). Using system GT instruments (Dentsply Malliefer, Switerzland). The teeth were split longitudinally into two, stained collagen was applied to the canal surfaces and the tooth reassembled for static and PUI. Digital images of the canal surface were taken before and after irrigation with 9, 18, 27 and 37 mL solution. The digital images were analyzed using ImageJ software (National Institute of Health, USA) to quantify residual canal coverage by the stained collagen. The data were analyzed using linear regression models and subjected to statistical analysis. RESULTS: The mean percentage of canal surface with residual collagen increased with the coronal level of canal, decrease in apical size and taper of canal preparation and decrease in the volume of the irrigant. There was less residual collagen after PUI compared with static irrigation. The canal surface facing the open side port of the needle had less residual collagen after irrigation than the opposing surface. CONCLUSION: The stained collagen biomolecular film could not be removed completely either by passive ultrasonic instrumentation or static irrigation. The PUI was found to be more effective in the removal of collagen, especially in the apical part of the root canal.
ABSTRACT
AIM: To evaluate microleakage in resin composite restorations after antimicrobial pre - treatments. MATERIALS AND METHODS: Forty freshly extracted non carious human premolars were procured. In all forty premolar specimens, class V preparation of standard dimension were prepared and were randomly divided into three experimental and one control group. In all control and experimental groups the class V preparations were restored with FILTEK Z350 composite restorative material. The experimental groups included different self etching primers and 2% Chlorhexidine gluconate. The control group included Xeno III and no antimicrobial pre-treatment was done for the control group. Thereafter these specimens were thermocycled, dried and sealed with nail varnish, leaving 1mm around the restoration and immersed in 0.5% basic fuchsin for 24 hours and then the specimens were subjected for microleakage evaluation. The results were statistically analyzed by Kruskal Wallis Test and Mann Whitney 'U' test. RESULTS: Results indicate that group II (2% chlorhexidine gluconate group) had the minimum mean value (15.05) and group III(Clearfil protect Bond group) and IV(control group) had the maximum mean microleakage at the enamel margin (23.00). At the gingival margin the lowest mean microleakage values were obtained with group I (Clearfil SE bond group) and group II (2% chlorhexidine gluconate) (20.25) and highest with group III and group IV (20.85). The difference was not statistically significant both at the enamel margin and the dentin margin (p>0.05). INTERPRETATION & CONCLUSIONS: Within the limitations of this in-vitro study, we conclude that: None of the materials tested in this study completely eliminated microleakage at the enamel and at the gingival margin.All of the tested materials provided better sealing at the enamel margin than at the gingival margin.
