Effectiveness of different gutta-percha techniques when filling experimental internal resorptive cavities.

AIM: To determine the quality of root fillings in teeth with artificial internal resorptive cavities filled with Thermafil, JS Quick-Fill, Soft Core, System B and Microseal, and by cold lateral compaction (LC) technique. METHODOLOGY: Sixty maxillary incisor teeth were selected. After access cavity preparation and root canal instrumentation, the roots were sectioned horizontally and artificial internal resorption cavities were prepared on the canal walls. The tooth sections were cemented together and the root canals were filled using one of six different techniques: Thermafil, JS Quick-Fill, Soft Core, System B and Microseal, and by LC. The roots were then divided at the level of the previous section and each root surface was photographed. Image analysis program was used to calculate the percentage of sealer, gutta-percha and void in the internal resorptive cavities. All measurements were analysed statistically using One-way ANOVA and Newman-Keuls tests. RESULTS: The Microseal technique filled 99% of the artificial resorptive area followed by LC (92%), SystemB (89%), Quick-Fill (88%), Thermafil (74%) and Soft-Core (73%). Warm gutta-percha compaction techniques filled the resorption areas with more gutta-percha than sealer (Microseal 68%, System B 62%) compared to the other techniques (LC 48%, Quick Fill 41%, Soft Core 34%, Thermafil 35%). In addition, core techniques left a considerable volume of voids in the resorptive areas (Quick-Fill 12%, Thermafil 26%, Soft Core 27%). CONCLUSIONS: Warm gutta techniques filled artificial resorption cavities significantly better than the other gutta-percha techniques.

Comparison of curved canals preparations using profile, GT and Hero 642 rotary files.

This study compared preparations of curved canals, using Profile, GT file and Hero 642 rotary files. A total of 30 mesiobuccal canals of extracted first and second mandibular molars were used in this study. The teeth were embedded in resin and a pre-operative radiograph was taken. The specimens were then randomly divided into three instrument groups. Pre- and post-instrumentation radiographic images were scanned and superimposed using the VISI CAD/CAM program. At nine horizontal sections at 1 mm increments from the apex, it calculated pre- and post-instrumentation cross sectional areas (mm(2)) and enlargements to the inner aspect and outer aspects (mm). A Kruskal-Wallis test found no statistical difference among the groups in terms of total areas removed by each instrument (P > 0.05). It also found no significant difference in any group between the total of the inner and outer enlargements (P > 0.05). However the GT file removed significantly more material from the outer side of the canal than the inside at sections 3-5, and the Hero removed significantly more material from the outer side at sections 7-9 (P < 0.05). All instruments produced preparations that maintained original canal curvatures.

A new silicon-based root canal sealer (Roekoseal-Automix).

This study evaluated the new silicon-based sealer 'Roekoseal-Automix' (RSA) with respect to sealing, bonding capabilities and biocompatibility with rat subcutaneous connective tissue. For the microleakage study, 36 single rooted teeth were instrumented and 30 of these obturated with either Grossman's sealer or RSA using lateral condensation technique (15 of each). Six teeth were not obturated and used as control group. For investigating bonding capability, 10 of the obturated roots with RSA and Grossman's sealer were ground and split longitudinally and examined by scanning electron microscopy (SEM). The RSA was found to seal significantly better than Grossman's sealer. The SEM examination revealed a good bond between RSA and the dentine and between RSA and the gutta-percha. Tissue reaction was evaluated by injecting 0.1 mL RSA into the connective tissue of 21 male Albino-Wistar rats and observing at 24 h, 7 days and 30 days and 30 days. Formation of a new granulation tissue with fibrous tissue adjacent to the material at 30 days. This study found that RSA performed well.

Comparison of different gutta-percha root filling techniques: Thermafil, Quick-fill, System B, and lateral condensation.

OBJECTIVES: In this in vitro study, the core (gutta-percha or gutta-percha and carrier)/sealer ratio and the sealing ability were calculated for 4 different gutta-percha techniques: Thermafil, JS Quick-Fill, System B, and lateral condensation. STUDY DESIGN: One hundred single-rooted teeth were instrumented and obturated. Forty of the teeth were embedded in resin and sectioned horizontally at 1, 2,3, and 4 mm from the anatomic apex. Photographs were taken of each section, and the total area of the canal filled with core material or sealer was calculated. Sixty of the teeth were kept in wet storage for 90 days, after which the teeth were immersed in 2% methylene blue for 48 hours. The length of dye penetration was measured. RESULTS: Roots obturated with Thermafil and JS Quick-Fill contained significantly more core material than did those obturated with System B or with lateral condensation. The lateral condensation technique had the lowest core/sealer ratio (P < .05). Roots using Thermafil and Quick-Fill showed significantly less dye leakage than did the lateral condensation technique. CONCLUSIONS: Through use of these techniques in vitro, Thermafil and JS Quick-Fill with carrier and System B were found to be superior to the lateral condensation technique in terms of core/sealer ratio. Thermafil and Quick-Fill were superior to lateral condensation in terms of dye leakage.

A comparative study of the area of the canal space obturated by thermoplasticized gutta-percha techniques.

Two thermoplasticized gutta-percha techniques were evaluated for the percentage area of canal obturated by gutta-percha and compared with the lateral condensation of gutta-percha technique. All obturation systems were used in conjunction with Grossman's sealer. Single rooted teeth were obturated by either injected thermoplasticized gutta-percha (Ultrafil), thermoplasticized gutta-percha with metal carrier (Thermafil) or lateral condensation of gutta-percha. There were ten specimens in each group. The teeth were embedded in resin, sectioned at 1.5 mm, 3 mm and 4.5 mm from the root apex and examined with a stereomicroscope. Specimens filled by Ultrafil and Thermafil contained a significantly higher percentage of gutta-percha than specimens filled by the lateral condensation technique at every level. However no difference was found between Ultrafil and Thermafil. Three lateral condensation specimens showed voids at the 1.5 mm section; no voids were detected in specimens filled by Ultrafil or Thermafil at any level.

Evaluation of sealing properties of Thermafil and Ultrafil techniques in the absence or presence of smear layer.

The apical sealing abilities of two thermoplasticized gutta-percha techniques were evaluated. A total of 128 single-rooted teeth were divided into six groups in which Ultrafil, Thermafil, and lateral condensation techniques, with and without the smear layer, were used to obturate 20 roots in each group. The roots were implanted subcutaneously in rats for 90 days to expose the materials to vital tissue and tissue fluids. The roots were recovered, immersed in 1% methylene blue for 2 wk, cleared, and the dye penetration was measured using a dissecting microscope. Thermafil showed the least leakage with smear layer present and Ultrafil the least with it absent. The two thermoplasticized gutta-percha techniques both showed significantly less leakage than lateral condensation with and without the smear layer. Removing the smear layer reduced the leakage significantly in all groups.

Dentinal wall adaptation of thermoplasticized gutta-percha in the absence or presence of smear layer: a scanning electron microscopic study.

The dentinal adaptation of injected thermoplasticized gutta-percha and thermoplasticized gutta-percha resulting from Ultrafil and Thermafil systems was evaluated by scanning electron microscopy and compared with adaptation obtained with the lateral condensation of gutta-percha. Each method was evaluated with and without the smear layer removed. Scanning electron microscopic observations showed the thermoplasticized gutta-percha resulting from either system to have better dentinal wall adaptation than lateral condensation of gutta-percha in either the absence or presence of the smear layer. In the absence of smear layer, the adaptation of gutta-percha was improved in all groups. Although sealer was used, removing the smear layer was found to enhance the ability of the thermoplasticized gutta-percha to enter the patent tubules.

Treatment of root-fractured maxillary incisor with Thermafil obturator.

This case report describes the treatment of a maxillary left central incisor with intra-alveolar horizontal root fracture in the middle of the root. The pulp of the coronal segment was necrotic and endodontic treatment was performed. Instrumentation of the root canal through the fracture line was carried out and the tooth was obturated with Thermafil in order to bring about a union of the fragments. At the 24-month follow up examination the tooth was functionally and esthetically normal. Radiographically no pathosis was evident in the periapical or fracture areas.

Antibacterial efficacy of root canal medicaments.

The antibacterial efficacy of four endodontic medicaments was studied in vitro. Calcium hydroxide (CALACEPT), camphorated parachlorophenol (CPCP), Cresophene, and 2% iodine-potassium iodide (IKI) were tested against four anaerobic microorganisms, Streptococcus mutans, Peptostreptococcus anaerobius, Porphyromonus gingivalis and Fusobacterium nucleatum, for 10 or 15 min. IKI was effective only against F. nucleatum and P. gingivalis, and the others were effective against all four microorganisms.

Investigation of surface corrosion in amalgam.

In this study, surface corrosion of carved and polished specimens of conventional and high-copper amalgams was investigated. The specimens were studied to detect surface corrosion after immersion in artificial saliva for 48 h or 1 year, and later investigated by SEM. Corrosion was greatest in 1-year-immersed carved conventional amalgam specimens. The surface was very rough with the contours of the particles visible and deep holes opening at the surface. High-copper amalgam specimens showed less corrosion than conventional amalgam specimens.

Streptococcus mutans in plaque from margins of conventional and high copper amalgam restorations.

Levels of Streptococcus mutans in plaque samples from margins of conventional and high copper amalgam restorations were compared in fourteen patients, each having one conventional amalgam filling in each quadrant and one high copper amalgam filling on the contra-lateral side were examined. The percentage of S. mutans of total CFU count in plaque was higher on conventional amalgam than on high copper amalgam. The difference was statistically significant (p < 0.01).