Evaluation of Apical Vapor Lock Formation and comparative Evaluation of its Elimination using Three different Techniques: An in vitro Study.

AIM: The aim of this study was (i) to evaluate the formation of air bubbles in the apical region of root canal (apical vapor lock) during syringe irrigation, using cone beam computed tomography (CBCT) and (ii) comparative evaluation of the elimination of an established vapor lock by EndoActivator, ultrasonics, and manual dynamic agitation (MDA), using CBCT. MATERIALS AND METHODS: A total of 60 extracted human single-rooted teeth were equally divided into three groups of 20 teeth each. The samples were decoronated 17 mm from the apex, cleaned, and shaped to size F4 Protaper using 3% sodium hypochlorite. Samples were irrigated with 3% sodium hypochlorite + cesium chloride radiopaque dye, and preoperative CBCT images were obtained. After formation of apical vapor lock in the scanned teeth, EndoActivator (group I), passive ultrasonic irrigation (group II), and MDA with K-file (group III) were performed and the teeth were again placed in CBCT scanner and results analyzed using the chi-square test. RESULTS: The apical vapor lock was formed in all the samples. Out of the 20 teeth in each group, the apical vapor lock was eliminated in 18 samples of EndoActivator group (90%), 16 samples of ultrasonic group (80%), while it was eliminated in 10 samples by MDA (50%). CONCLUSION: It is concluded that (1) apical vapor lock is consistently formed during endodontic irrigation in closed canal systems and (2) sonic activation performs better than the ultrasonics and MDA in eliminating the apical vapor lock, with statistically significant difference between all the three groups (p < 0.05). CLINICAL SIGNIFICANCE: The results suggest that the apical vapor lock (dead water zone) is consistently formed during routine endodontic irrigation which impedes irrigant penetration till the working length, thereby leading to inefficient debridement. Hence, to eliminate this vapor lock, techniques, such as sonics or ultrasonics should be used along with the irrigant after shaping and cleaning of the root canal.

Efficacy of Different Root Canal Irrigating Solutions in Removing Smear Layer: A Scanning Electron Microscopic Study.

Background The aim of the present investigation was to evaluate and compare the efficacy of frequently used chemical agents in terms of their capacity to eliminate the smear layer after instrumentation, as observed via scanning electron microscopy (SEM). Materials and methods Sixty extracted single-rooted mandibular premolar teeth, each with roots 15 mm in length, were used in this study. The teeth were divided into one control group and four study groups, each containing 12 teeth. In Control Group 0, teeth were irrigated with 3 ml of saline only. In Group 1, teeth were irrigated initially with 3% sodium hypochlorite (NaOCl) and then given a final rinse with 3 ml of 17% ethylenediaminetetraacetic acid (EDTA) for one minute. In Group 2, teeth were irrigated with 3% NaOCl and given a final rinse with 3 ml of a mixture of tetracycline, acid, and detergent (MTAD, BIOPURE) for one minute. In Group 3, teeth were irrigated with saline and given a final rinse with 3 ml of 17% EDTA for one minute. In Group 4, teeth were irrigated with saline and given a final rinse with 3 ml of MTAD for one minute. One-half of each tooth was chosen and prepared for scanning electron microscopic (SEM) examination at the cervical, middle, and apical thirds. These were observed at magnifications of up to 1,000 times to check for the presence or absence of a smear layer. The data were analyzed using the Kruskal-Wallis test and post-hoc Dunn's test. Results All of the root canal irrigation protocols exhibited superior efficacy compared to the control group in the elimination of the smear layer. Group 2 (3% NaOCl with MTAD) showed the lowest mean scores, compared to all the groups, followed by Group 1 (3% NaOCl with 17% EDTA). MTAD was more effective than EDTA. The smear layer was effectively removed from the apical third, followed by the middle and coronal thirds of the root. Conclusion Initial irrigation with 3% NaOCl and one-minute final irrigation with 3 ml MTAD was the most effective root irrigant, and particularly indicated in teeth with infection of the apical third.

Cephalometric evaluation-based on Steiner's analysis on young adults of Chhattisgarh, India.

AIM: The study was conducted to establish skeletal and dental parameters for Chhattisgarhi young adults, evaluation of variability between male and female Chhattisgarhi normal occlusion subjects and comparison of Cephalometric norms of Chhattisgarh population with Caucasians as well as other non- Caucasian groups. MATERIALS AND METHODS: A Cephalometric study of 80 Chhattisgarhi young adults (40 males and 40 females) with acceptable profile and occlusion was carried out by means of Steiner's analysis. RESULTS: In comparison to the Caucasian samples, the Chhattisgarhi samples were more protrusive skeletally and dentally and exhibited a more horizontal growth pattern than the Caucasians. The females reported with an increased incisor procumbency, prominent chin and prognathic maxilla than their male counterparts. CONCLUSION: The results of the study support the fact that a case of malocclusion cannot be treated to a template of norms which have been derived from mean values of a certain select group of subjects with excellent occlusion and harmonious facial proportions. CLINICAL SIGNIFICANCE: A case of malocclusion needs to be treated based on the individual merits and demerits of that case and not based on template of norms derived from mean values of select subject groups with ideal occlusion and proportion.

Comparative evaluation of resistance failure in nonprecious metal-ceramic restoration at the incisal edge with varying thickness under different application of load: an in vitro study.

OBJECTIVE: To determine the resistance failure value of nonprecious metal-ceramic restorations at the incisal edge with varying thickness under different application of load. MATERIALS AND METHODS: An Ivorian central incisor was prepared to receive metal-ceramic crown, which was further duplicated, invested, casted and 72 metal dies were fabricated in Co-Cr alloy. Metal dies were relieved with die spacer, lubricated and wax patterns were prepared for metal copings, which were further invested and casted and 72 metal copings were fabricated. The ceramic materials were used for the study viz. Vita/VMK, IPSd SIGN, and superporcelain. Ceramic built-up was carried out according to manufacturer instructions. Incisal ceramic built-up was carried out with increasing thickness from 2.00 to 2.5 and 3.00 mm. RESULTS: A total of 72 samples, prepared for the study, were divided into two groups, i.e. group I (36 samples) and group II (36 samples), as per the direction of application of load. The samples were mounted on acrylic block (6 samples/block). A total 12 acrylic blocks were prepared. All the samples were tested using universal testing machine (MTS/USA). The load was applied with crosshead speed of 5 mm/min. CONCLUSION: Fracture resistance was found to be highest for the 2.00 mm and lowest for 3.00 mm incisal ceramic thickness samples regardless of the ceramic material in both groups. There was a gradual decrease in fracture resistance as the incisal ceramic thickness increased from 2.00 to 3.00 mm in all samples. Fracture resistance was marginally higher for incisal ceramic build-up of 3 mm thickness on group II metal copings than on group I copings. Fracture resistance was highest for IPSd SIGN followed by that of Vita/VMK-95 and superporcelain. CLINICAL SIGNIFICANCE: A 3.00 mm incisal ceramic thickness offered greater fracture resistance in comparison to lower values of incisal thickness; IPSd SIGN offered greatest fracture resistance followed by that of Vita/VMK-95 and superporcelain.

Effect of acidic environment and intracanal medicament on push-out bond strength of biodentine and mineral trioxide aggregate plus: an in vitro study.

INTRODUCTION: This in-vitro study aims to evaluate the effect of acidic environment and intracanal medicament on push out bond strength of Biodentine and Mineral Trioxide Aggregate Plus (MTA Plus). METHOD: Forty extracted single rooted teeth were sectioned below the cement-enamel junction. The root canals were instrumented using rotary files and then peeso reamer was used to obtain standardized root canal dimension. Specimens were randomly classified into following groups- Group 1: calcium hydroxide in the absence of acidic environment; Group 2: calcium hydroxide in the presence of acidic environment; Group 3: no intracanal medicament in the absence of acidic environment; Group 4: no intracanal medicament in the presence of acidic environment. Specimens were kept for 7 days at room temperature. Thereafter, specimens of each group were transversely sectioned into 1 mm thick slices and divided into 2 sub-groups according to the use of biodentine and MTA Plus. Using Universal Testing Machine, push out bond strength test was carried out and the data were analyzed statistically. RESULTS: There was no statistically significant difference in the bond strength of biodentine and MTA Plus (P>0.05). For both MTA Plus and biodentine, with or without calcium hydroxide, the push out bond strength was less in acidic environment and this difference was more pronounced without calcium hydroxide. In all the four groups, MTA plus showed comparable bond strength to biodentine. CONCLUSION: MTA Plus is a viable option for apexification. The push out bond strength of Biodentine and MTA Plus is impaired by acidic environment. Prior application of calcium hydroxide slightly increased the bond strength, though the difference was statistically insignificant.