Alexandre Capelli

Evaluation of apical microleakage of teeth sealed with four different root canal sealers

Objectives: to compare the apical sealing ability of four root canal sealers. Materials and methods: forty extracted human maxillary canines were instrumented 1 mm short of the anatomical apex and randomly assigned to four groups (n=10), according to the root canal sealer used for obturation: Endofill, AH Plus, EndoREZ and Epiphany. Root canals were obturated with guttapercha points, except for the Epiphany group, in which resin points (Resilon) were used. The teeth were immersed in India ink for seven days and clarified using methyl salicylate. The extent of apical dye penetration was measured with a measuroscope in all aspects of the canal. Results: AH Plus (0.02 mm ± 0.07), Epiphany (0.00 mm ± 0.00) and EndoREZ (0.32 mm ± 0.62) did not differ statistically to each other (p>0.01). EndoFill presented the highest dye penetration mean (0.83 mm ± 0.73) and was statistically different from the other sealers (p<0.01). Conclusions: the resin-based root canal sealers presented lesser apical microleakage than the zinc oxide and eugenol based sealer. No statistical differences were observed among resin based sealers.

Influence of cervical preflaring on apical file size determination in maxillary lateral incisors

The purpose of this study was to investigate the influence of cervical preflaring on determination of the initial apical file in maxillary lateral incisors. Forty human lateral incisors with complete root formation were used. After standard access cavities, a size 06 K-file was inserted into each canal until the apical foramen was reached. The WL (WL) was set 1 mm short of the apical foramen. Four groups (n=10) were formed at random, according to the type of cervical preflaring performed. Group 1 received the initial apical instrument without previous preflaring of the cervical and middle root canal thirds. Group 2 had the cervical and middle root canal thirds enlarged with nickel-titanium Orifice Opener instruments. Group 3 had the cervical and middle root canal thirds enlarged with Gates-Glidden drills. Titanium-nitrite treated, stainless steel LA Axxess burs were used for preflaring the cervical and middle root canal thirds of group 4. Each canal was sized using manual K-files, starting with size 08 files with passive movements until the WL was reached. File sizes were increased until a binding sensation was felt at the WL, and the instrument size was recorded for each tooth. The apical region was then observed under a stereoscopic magnifier, images were recorded digitally and the differences between root canal and maximum file diameters were recorded (in mm) for each sample. Significant differences were found between the groups regarding the anatomical diameter at the WL and the first file to bind the canal (p = 0.01). The major discrepancy was found when no preflaring was performed (0.1882 mm average). Canals preflared with Orifice Opener instruments (0.0485 mm average) and Gates-Glidden drills (0.1074 mm average) also showed great discrepancy. The LA Axxess burs produced the smallest differences between anatomical diameter and first file to bind (0.0119 mm average). Instrument binding technique for determining anatomical diameter at WL was not accurate. Preflaring of the cervical and middle thirds of the root canal improved anatomical diameter determination; the instrument used for preflaring played a major role on determination of the anatomical diameter at the WL. Canals preflared with LA Axxess burs created a more accurate relationship between file size and anatomical diameter.

Shock of paradigms on the instrumentation of curved root canals

This paper makes a practical analysis about the paradigm on the instrumentation of curved root canals. In Endodontics, a paradigm has been created. Theories and techniques for instrumentation of curved root canals state that the use of a #25 file in the apical portion fulfills all the requirements for cleaning and shaping of the root canal system. Every scientific theory or paradigm should be continuously opened to modifications or refutation. The existence of extremely flexible instruments fabricated from metal alloys, methods for accurate determination of the real anatomic diameter and achievement of optimal shaping and cleaning of the apical portion created new theories and a new paradigm on the instrumentation of curved root canals. Therefore, this new insight will gradually modify the mentality of researchers and clinicians, but will still be open to further investigations and theories.

In vitro evaluation of the thermal alterations on the root surface during preparation with different Ni-Ti rotary instruments

The present study evaluated, in vitro, the temperature alterations on the external root surface during instrumentation with four different rotary systems. A total of 20 extracted human maxillary lateral incisors were instrumented using either the ProFile, MicroMega, Quantec or K3 systems and the thermal alterations on the root surface were recorded by means of three thermocouples attached to the coronal, middle and apical portions of the root. Mean temperature increases no higher than 0.4 degrees C +/- 1.0 degrees C (ProFile system) were recorded, which indicates that these instruments are safe for the surrounding periodontal tissues.

Influence of gutta-percha points on the filling of simulated lateral canals.

The aim of this study was to investigate, in vitro, the percentage of filling of simulated lateral canals in teeth obturated with TP medium and standardized gutta-percha points. Twenty human mandibular canines were prepared with LA Axxess (SybronEndo) and K³ Endo rotary system (SybronEndo) up to a #50 file, according to the Free Tip Preparation Technique. During instrumentation, the root canals were alternately irrigated with 1% sodium hypochlorite and 17% EDTA. Six artificial lateral canals were prepared at the apical third of each tooth. Then, the teeth were assigned to two groups (n=10): Group 1 - filled with TP medium master gutta-percha points (Dentsply, Mailleffer); Group 2 - filled with standardized master gutta-percha points (Dentsply, Mailleffer). Root canal filling was complemented with AH Plus sealer (Dentsply, Mailleffer) and accessory gutta-percha points (Dentsply, Mailleffer), according to the classic technique. The teeth were radiographed and the images obtained were digitized. Linear measurements of the percentage of filling of the artificial lateral canals in each group were accomplished on the Image Tool 2.02 software. Statistical analysis of the data using Mann-Whitney U non-parametric test evidenced significant difference (p<0.01) between the experimental groups. The group obturated with TP medium points yielded higher percentage of filling of the lateral canals. It may be concluded that the use of master gutta-percha points with larger taper resulted in better filling of the simulated lateral canals, as compared to the use of standardized master gutta-percha points.

Er:YAG laser evaluation of smear layer removal from flattened root canals submitted to rotary instrumentation

This study evaluated smear layer removal of 40 mesio-distal flattened root canals after rotary instrumentation. Teeth were divided into 4 goups: Group 1: 2.5% sodium hypochlorite was used as an irrigating solution; Group 2: instrumented as Group 1 followed by Er:YAG laser irradiation (140mJ input/10Hz, withdrawn at 2mm/s from the apical to the cervical region touching the buccal wall; the procedure was then repeated for the lingual wall); Group 3: instrumented as Group 1 and followed by Er:YAG laser irradiation (250mJ input/10Hz, in the same way as described for Group 2) and Group 4: instrumented as Group 1 and alternated with 17% EDTA. Teeth were then split longitudinally and prepared for examination under the scanning electron microscope. Scores from 1 to 4 were given to the fotomicrographs by three independent evaluators, and these data were submitted to statistical analysis. Teeth where alternated 17% EDTA was used (Group 4) showed less amount of smear layer, followed by the group irradiated with 250mJ input/10Hz (Group 3), the group irradiated with 140mJ input/10Hz(Group 2) and the group where only sodium hypochlorite was used (Group 1). The apical third presented more smear layer than the middle third (p<00.1)

In vitro evaluation of smear layer removal of root canals by irradiation with Er:YAG laser after Ni-Ti rotary instrumentation

The smear layer removal of root canal walls irradiated with Er:YAG laser after nickel-titanium rotary instrumentation was evaluated by scanning electron microscopy. Thirty mesial roots of human mandibular molars were selected and randomly distributed in three groups, according to treatment. Group 1 was instrumented with rotary nickel-titanium files 1 mm from the anatomical apex and irrigated with 2.5% sodium hypochlorite. Group 2 received the same treatment as Group 1, but after instrumentation the root canals were irradiated with Er:YAG laser. Group 3 received the same treatment as Group 1, but irrigation was performed with 2.5% sodium hypochlorite alternated wtih 17% EDTA during instrumentation. Photomicrographs were obtained from middle and apical thirds and submitted to qualitative evaluation. Statistical analysis showed that 2.5% sodium hypochlorite associated with 17% EDTA (Group 3) removed smear layer more efficiently than 2.5% sodium hypochlorite al one (Group 1) (p<0.05). Root canals irradiated with Er:YAG laser occupied an intermediary position regarding smear layer removal. There were no statistical differences between the evaluated radicular thirds (p>0.05).