Effect of diode laser irradiation on the apical sealing of MTA retrofillings

Apical sealing is essential for the success of paraendodontic surgery, so any procedure that may favor an adequate sealing of the apical remainder should be performed. The purpose of this study was to evaluate the influence of diode laser irradiation on the apical sealing of root-end cavities with MTA retrofillings. Root canals in twenty extracted human teeth were shaped with K-files and filled with gutta-percha. The apexes were cut off and root-end preparations were performed. The roots were divided randomly in 2 groups. Group 1 (ten specimens) was retrofilled with MTA. Group 2 was irradiated with diode laser, with 1 W for 20 seconds, on the apical surface and root end cavity before retrofilling with MTA. The specimens had their external surfaces impermeabilized with cyanoacrylate, except for the apical surface, and were then immersed in 1% rhodamine B dye for 72 h and placed in plaster stone. After that, the specimens were submitted to longitudinal abrasion until half of the root remained. The linear dye leakage was observed in these mid-roots between the root canal wall and retrofilling. The linear dye leakage was measured with Image Lab software, and the results were statistically analyzed with Student's t test. There were no statistically significant differences between the two groups (p > 0.05). The diode laser irradiation did not improve the apical sealing of MTA retrofillings under the conditions of this in vitro study.

Effect of different dye solutions on the evaluation of the sealing ability of Mineral Trioxide Aggregate

Alkaline materials have shown incompatibility with methylene blue dye in leakage experiments. The goal of the present study was to analyze the effect of different dyes on the evaluation of the apical sealing ability of Mineral Trioxide Aggregate root-end fillings. Fifty-six extracted human canines were submitted to root canal instrumentation and obturation. After apical resection, retrograde cavities were prepared and teeth were randomly divided into four experimental (n = 13) and two control groups (n = 2). The following root-end filling materials were used: groups 1 and 2--Pro Root MTA (Dentsply), groups 3 and 4--zinc oxide-eugenol cement (ZOE). Teeth in groups 1 and 3 were immersed in 2% methylene blue solution, while teeth in groups 2 and 4 were immersed in 0.2% rhodamine B in a reduced pressure environment for 48 hours. Teeth were then longitudinally sectioned and leakage was evaluated. Results were submitted to statistical analysis (ANOVA and Tukey's test). Group 1 presented the least leakage (p < 0.05). It was concluded that the evaluation of the sealing ability of MTA is influenced by the dye used, since this material presented better sealing ability when evaluated with Methylene Blue, but was similar to ZOE when evaluated with rhodamine B.

Levels of evidence for the outcome of endodontic surgery

The purpose of this investigation was twofold: (1) to search for clinical articles pertaining to success and failure of periapical surgery and (2) to assign levels of evidence to these studies except case reports. Electronic and manual searches were conducted to identify all the literature regarding success and failure of periapical surgery since 1970. Articles were reviewed, and each article was assigned to a level of evidence from 1 (highest level) to 5 (lowest level). This search located 79 clinical studies. Among these studies, there were no level of evidence-1 randomized clinical trial studies. Five of the seven level of evidence-2 randomized clinical trials compared postoperative pain between surgical and nonsurgical retreatment. Only two level of evidence-2 randomized clinical trials compared the outcomes of surgical treatment with that of nonsurgical treatment. The majority of frequently quoted "success and failure" studies were case series (level of evidence 4).

A standard for radiopacity of root-end (retrograde) filling materials is urgently needed

AIM

To assess the radiopacity of materials used, or recommended for use, as apical root-end (retrograde) fillings.

METHODOLOGY

The radiopacity of 14 materials falling into the category of root-end filling materials was measured in equivalent millimetres of aluminium (mm Al) using a new computerized method. These included temporary or intermediate sealing materials; composite, compomer and GIC filling materials; EBA-derived cements; amalgam, etc. Gutta-percha cone material was added as a control. Samples of 1 mm thickness were radiographed on periapical film alongside an aluminium step wedge calibrated in millimetres, and the opacity of the materials, in greyscale or pseudo-colour, was compared with the equivalent step.

RESULTS

The radiopacity ranged from 1.75 mm Al to >10 mm Al. The lower range appears insufficient for routine clinical detection when it is compared with the minimal requirement for intracanal fillings.

CONCLUSIONS

Because of the proliferation of root-end filling materials with a broad range of radiopacity, an international standard stipulating the required minimal radiopacity, as well as other properties, is needed urgently. It should be based on in vitro results and on large-scale clinical radiographic surveys.

The quality of ultrasonic root-end preparation: a quantitative study

Ultrasonic root-end preparation techniques have recently been introduced and revolutionized the field of endodontic surgery. The purpose of this study was to compare quantitatively the quality of root-end preparation techniques prepared by a specially designed ultrasonic retrotip with those prepared in a traditional manner by a microhandpiece bur. Twenty roots with two canals and an isthmus from extracted maxillary human molars were selected for this study. After instrumentation, obturation, and root-end resection, root-end preparations were made using either an ultrasonic retrotip or a conventional microhandpiece bur. With the aid of the image processing and analysis system, the specimens were inspected under a stereomicroscope for further evaluation of the quality of the shape and size of preparation. The results of this investigation showed that the ultrasonic root-end preparations produced more conservative and less perforated cavities than those made with conventional microhandpiece bur preparations.

[Comparative study of the sealing properties of retrograde amalgam root fillings using a microtechnic and the naked eye]

The aim of the present investigation was to compare the quality of retrograde amalgam fillings made under the control of the naked eye and that of a stereomicroscope. The 58 extracted upper incisors used for study had been divided into two groups and were filled with one of the control methods. In both groups on 25 teeth the microleakage was assessed by dye diffusion, the surfaces of the remaining 4 teeth were subjected to SEM examination. The depths and angle belonging to the stained sections of the perimeter had been measured under a stereomicroscope with a magnification of 40 and the area affected was calculated. Significantly (p less than 0.001) less area was involved in the stereomicroscopic group (1.46 +/- 0.34 mm2) than in the naked eye group (3.89 +/- 1.80 mm2). The SEM photographs demonstrated the faults which can be eliminated by the use of a stereomicroscope and showed also those which derive from the physical and chemical properties of the amalgam.

Comparison of apical sealing methods. A preliminary report

A comparison of the seal provided by gutta-percha root canal filling, heat-sealed gutta-percha, retrograde amalgam filling, and retrograde Durelon filling was made by observation of dye penetration around the above filling materials in extracted teeth. A small but not significant difference between gutta-percha, heat-sealed gutta-percha, and retrograde amalgam was noted. Retrograde Durelon filling gave a poor seal in comparison to gutta-percha and retrograde amalgam filling, but the difference between it and the heat seal was not significant.