Relationship between post-preparation pain and apical patency: a randomized clinical trial

This study was conducted to compare the post-preparation pain experience following root canal preparation with or without achieving and maintaining apical patency during root canal preparation. Root canal preparation was completed in the first visit for eighty patients. The patients were divided randomly into two groups where patency was either established and maintained during preparation or not. Pain was recorded before treatment, 6,12,18,24 and 48 hours after treatment. Patients assessed their severity of pain over the first two days following root canal preparation using a modified visual analog scale of [0-9]. Our results showed that no significant difference was found between the two groups. No significant difference was found between the two groups studied. No significance was found between all the previous preoperative clinical and radiographic findings and post-preparation pain, except preoperative pain. Apical patency did not increase the post preparation pain significantly

Comparative evaluation of sealing ability of three Root Canal sealers with and without smear layer removal

Successful root canal treatment requires a complete obturation of the root canal system, the study of the sealing ability of different sealers especially the newly introduced ones will be of value for proper root canal treatment. Moreover, the sealing quality of these sealers in the presence or absence of smear layer may be of additional benefit. This study was designed to evaluate the sealing ability of three root canal scalers namely Endofill, GuttaFlow, Endo REZ .with removal of the smear layer or not. A total number of 120 human single rooted teeth were collected for the study. Their root canals were cleaned and shaped using crown down technique using Profile .04 taper rotary files, samples were divided into two equal main groups according to the irrigating solution used as final rinse. Samples of G1 had the smear layer preserved due to irrigation with 5.25% NaOC1 solution. Samples of G2 had the smear layer removed due to irrigation with 17% EDTA solution. Each main group subdivided into four equal subgroups according to the sealer used for obturation.Samples of subgroup A obturated with Zinc Oxide and eugenol based sealer [Endofill], Samples of subgroup B obturated with Silicon based sealer [GuttaFlow], Samples of subgroup C obturated with resin based sealer [Endo REZ] and Endo REZ master cone, samples of subgroup D obturated with Endo REZ and Gutta-Percha master cone .The stereomicroscope [magnification x20] was used to determine dye penetration depth in millimeter. The measurements showed that Zinc Oxide and eugenol based sealer [Endofill] had the highest leakage values between the other scalers in both conditions, Silicon based sealer [GuttaFlow]had the least leakage values which was significant from leakage values of [Endofill] and [Endo REZ with gutta percha master point]] but was not significant from [Endo REZ and Endo REZ master cone]. The smear layer removal using 17% EDTA solution did not significantly improve the sealing ability of the tested sealers

effect of apical termination of Root Canal preparation on postoperative pain [clinical study]

This study was conducted to evaluate the effect of apical terminus location of the root canal preparation on postoperative pain. Root canal preparation was completed in the first visit for sixty patients .The working length of the root canals were determined electronically by using apex locator and confirmed radiographically. The patients were divided randomly into three main groups according to apical termination of preparation [0.0, 0.5 and 1mm away from the apical foramen]. They recorded pain before treatment, 6, 12, 18, 24 and 48 hours after treatment. They assessed their severity of pain over the first two days following root canal preparation using a modified visual analog scale of [0-9]. Our results showed that Preparation to the apical foramen produced the highest significant level of postoperative pain at most of the time intervals. Otherwise no significant difference was found between the other groups

influence of apical patency on transportation of the Root canal [laboratory study]

This study was undertaken to evaluate the effect of apical patency on transportation of the apical foramen. Forty extracted human straight single rooted teeth with mature apices were used. The root of each tooth was mounted in a square piece of silicone leaving foramen on top. The specimens were randomly divided into two groups whether patency was established and maintained during preparation or not. Initial and final photographs of apical foramen were taken before and after instrumentation using a stereomicroscope. The images of each specimen [pre and post] were superimposed to determine transportation. No significant difference was found between the studied groups

Effect of the degree of polymerization on the intrinsic discoloration of light activated resin composite restorations

This study was carried out to investigate the effect oft he degree of polymerization on the intrinsic discoloration of light activated resin composite restorations. Three different commercially available resin composites were used in this study. Each group was subdivided into three sub groups, according to time of curing. Half of the specimens in each sub group, where stored in dry condition while the other half was stored in coffee. Color was assessed by the spectrophotometer and degree of polymerization was measured by FTIR. The collected data were statistically analyzed using two way analysis of variance [ANOVA]. Reverse relationship was found between the intrinsic discoloration and the degree of polymerization. The curing time should not be less than 40 sec. to ensure better color stability of different resin composites