One-year clinical evaluation of the efficacy of a new daytime at-home bleaching technique

The aim of this study was to compare the clinical efficacy and side effects of a new daytime at-home bleaching technique (28% carbamide peroxide [CP] gel) with the overnight application of 10% CP and to determine the change of tooth color 1-year post-treatment. Twenty healthy volunteers were assigned to one of two sample groups of 10. All participants employed one of the two at-home bleaching systems: (1) the new daytime at-home bleaching system including 28% CP gel with a non-custom-fit tray (Meta Tray, Remedent, Deurle, Belgium) for 20 minutes, and (b) the conventional overnight at-home bleaching system with a 10% CP gel and a custom-fit tray (Opalescence PF, Ultradent, South Jordan, UT, USA) for 6 to 8 hours. Digital images and CIE (International Commission on Illumination) L*, a*, and b* spectrophotometric measurements were taken at baseline, after the bleaching treatment and 1-year post-treatment. Tooth and gingival sensitivity was measured with a specially designed 4-point scale. Significant differences were found in L*, a*, and b* values, between initial and post-treatment, for both bleaching systems (p < 0.05). However, no significant difference was detected between post-treatment and 1-year follow-up. The bleaching effectiveness of Opalescence PF was found to be superior to that of Meta Tray, considering the color parameter of DeltaE (p < 0.05). Meta Tray provoked less tooth sensitivity (p < 0.05), however gingival sensitivity appeared more in this group (p < 0.05). Within the limitations of this study, it can be concluded that the new daytime at-home bleaching system tested (Meta Tray) produced significant bleaching effects. However, the clinical efficacy of the overnight bleaching system was found to be superior to the daytime at-home bleaching system evaluated in this study. The whitening effect remained similar 1-year after the bleaching treatment for both at-home bleaching systems. CLINICAL SIGNIFICANCE Although the new daytime at-home bleaching system tested exhibited significant bleaching effects, overnight bleaching with a 10% CP gel resulted in a higher bleaching effectiveness than this new system. Although the participants using the new bleaching system exhibited less tooth sensitivity probably because of the reduced contact time of bleaching gel with tooth surfaces, the application of the bleaching agent with a non-customized tray provoked more gingival sensitivity in this group.

Influence of fluoride- or triclosan-based desensitizing agents on adhesion of resin cements to dentin

Effect of desensitizers on the bond strength of resin cements to dentin was evaluated. Intact premolars (N = 90) were embedded in polymethyl methacrylate; dentin surfaces were exposed, and they were randomly divided into two main groups of cements (Duolink (D), Variolink II (V); n = 45 per group) and then into three desensitizer subgroups (n = 15 per subgroup). Teeth in controls (C) were treated according to cements' adhesion protocols; the other two groups received either fluoride- [Aqua-Prep F (F)] or triclosan-based [Seal&Protect (T)] desensitizers. Ceramic disks (Empress 2) were adhered; specimens were thermocycled (×5,000 cycles, 5-55 ± 1°C, dwell time 30 s) and subjected to shear bond strength test (MPa ± SD) in a universal testing machine (crosshead speed 1 mm/min). Failure types were classified using scanning electron microscope. For V, application of both desensitizers (29.6 ± 7.8 and 22.8 ± 2.8 for F and T, respectively) did not present significantly different results than that of the VC (21.2 ± 2.3; p > 0.05, one-way ANOVA). In D, F (20.6 ± 2.4) showed significantly higher results (p < 0.05) than those in T (16.1 ± 3.9) and DC group (15.2 ± 2.3). V showed significantly higher results than D (p < 0.05, Bonferroni). F and T did not negatively affect the bond strength results with D and V. Adhesive failures were more frequent with both T (84%) and F (66%) in D; cohesive failures in the cement (88%) were more commonly observed with F in V. Both F and T desensitizers can be safely used prior to final cementation but F in combination with V seems to be more reliable, considering both the bond strength and the failure types.

Bond strength of different dentin bonding systems to fluorotic enamel

PURPOSE

The effect of three different bonding strategies on the shear bond strength of a resin composite to fluorotic enamel surfaces was investigated.

MATERIALS AND METHODS

Thirty-six noncarious extracted human molars with fluorosis and 36 without fluorosis were scraped clean from any remaining tissue, and then were divided into three subgroups according to the tested dentin bonding systems. The resin composite was bonded to the teeth using three different adhesive systems: Peak LC Bond with an etch-and-rinse technique (Ultradent Products), Peak LC Bond with a self-etching technique using Peak SE Primer (Ultradent Products), and Xeno V (Dentsply Caulk) using a one-bottle self-etching technique. Following the photopolymerization of the resin composites, thermocycling was performed 5000 times. Shear bond strengths were tested using the Shimadzu Universal Testing Machine until failure. The analysis of the fractured enamel surfaces was performed using an optical microscope (Nikon ECLIPSE ME 600) at 10X and 1000X magnification, and the images were analyzed with an image analyzer (LUCIA 4.21). The data obtained were analyzed with two-way ANOVA and the Bonferroni test at a significance level of p < 0.05.

RESULTS

Mean shear bond strengths in MPa of the groups were: Peak LC Bond, self-etching, on fluorotic enamel 13.23 +/- 2.58 and on nonfluorotic enamel 17.81 +/- 2.90; Peak LC Bond, etch-and-rinse, on fluorotic enamel 16.77 +/- 2.32 and on nonfluorotic enamel 21.13 +/- 2.74; one-bottle self-etching Xeno V on fluorotic enamel 10.79 +/- 2.14 and on nonfluorotic enamel 14.58 +/- 2.99.

CONCLUSION

Fluorosis adversely affected the bonding performance of all the bonding systems to enamel. The use of the etch-and-rinse dentin bonding technique produced higher bond strengths of the resin composite tested to fluorotic and nonfluorotic enamel compared to both self-etching techniques.

Effect of Er,Cr: YSGG Laser on the Microtensile Bond Strength of Two Different Adhesives to the Sound and Caries-affected Dentin

The microtensile bond strength of a three-step etch-and-rinse and a two-step self-etch adhesive is not negatively affected by Er,Cr:YSGG laser irradiation in sound and caries-affected dentin.

Can the hydrogel form of sodium ascorbate be used to reverse compromised bond strength after bleaching?

PURPOSE

To assess the effect of the hydrogel form of different concentrations (2.5%, 5%, and 10%) of sodium ascorbate on the shear bond strength of composite after bleaching of the enamel with 10% carbamide peroxide gel.

MATERIALS AND METHODS

Sixty flat buccal enamel surfaces obtained from 30 bovine incisors were divided into 6 treatment groups: group I, control (nonbleached); group II, no antioxidant treatment after bleaching; group III, 10% sodium ascorbate solution after bleaching; group IV, 2.5% sodium ascorbate hydrogel after bleaching; group V, 5% sodium ascorbate hydrogel after bleaching; group VI, 10% sodium ascorbate hydrogel after bleaching. The specimens were bonded with Clearfil SE Bond, then thermocycled and subjected to the shear test until failure. Fracture analysis of the bonded enamel surfaces was examined using a stereomicroscope. Statistical analysis was carried out using Kruskal-Wallis and the Mann-Whitney U-test.

RESULTS

While the samples that were not treated with antioxidant after bleaching (group I) demonstrated significantly lower shear bond strengths and the 10% sodium ascorbate gel group (group VI) demonstrated significantly higher bond strengths than the control group (p < 0.05), no significant differences were found between the other groups and control group (p > 0.05). Among the antioxidant groups, only the groups treated with the 10% solution and the 10% hydrogel form of sodium ascorbate (group III and VI) revealed significantly higher bond strengths than the bleached group without antioxidant (group II) (p < 0.05). Higher scores were obtained with 10% sodium ascorbate gel (group VI) when compared with the other antioxidant-treated groups (p < 0.05).

CONCLUSION

Within the limitations of this study, it can be concluded that the 10% hydrogel form of sodium ascorbate may be used in clinical procedures instead of its solution form. However, using sodium ascorbate hydrogel with concentrations lower than 10% may not be as reliable as using this agent in 10% concentration for reversing the compromised bond strength.

Effect of different laser devices on the composition and microhardness of dentin

This study determined the compositional changes and microhardness of the cavity floor prepared by Er,Cr:YSGG and Er:YAG lasers and compared the results with the conventional method of bur preparation. Fifteen non-carious human molars were used in this study. On the buccal and lingual surfaces of each tooth, two cavities (mesio-distal 3 mm, inciso-gingival 3 mm, depth 2 mm) were prepared with two different laser devices (Er,Cr:YSGG laser; Waterlase MD and Er:YAG laser; KaVo Key Laser 3) and a high-speed turbine. The teeth were embedded into polyester resin and cross-sectioned. The microhardness measurements from the floor of each half cavity were recorded with the Vickers surface hardness tester. The remaining halves of the cavities were subjected to SEM-EDS atomic analysis. The results were statistically evaluated by one-way ANOVA and Kruskal Wallis tests (p = 0.05). No significant differences were observed among the microhardness values, quantities of Ca (Ca weight %), P (P weight %) and Ca/P ratio of the lased and conventionally prepared cavities (p > 0.05). The cavity preparation techniques and differences in laser devices did not significantly alter the composition and microhardness of dentin tissue. Both laser devices used in this study were observed to lead to minimal thermal damage in the dentin tissue and minimal thermally-induced changes in dentinal compositions.

Oxygen release of tetra acetyl ethylene diamine (TAED) and sodium perborate combination

AIM

To evaluate the effect of tetra acetyl ethylene diamine (TAED) on oxygen release from sodium perborate and to compare it with sodium perborate-hydrogen peroxide (H(2)O(2)) and sodium perborate-distilled water mixtures.

METHODOLOGY

Six groups were evaluated: control groups (groups I-III), sodium perborate was mixed with distilled water or 3% or 30% H(2)O(2); experimental groups (groups IV-VI), sodium perborate was mixed with TAED in different ratios and then distilled water was added to these mixtures. The amount of oxygen released from the samples was measured with a digital oxygen meter at room temperature (25 degrees C) and body temperature (37 degrees C) after 1 min, 1-6 h and 12 h and on each day up to 1 week. The results were statistically evaluated by one-way analysis of variance and post hoc Tukey's tests.

RESULTS

The TAED groups demonstrated significantly higher amounts of released oxygen after 1 min and 1 h at 25 degrees C and 1 min at 37 degrees C (P < 0.05). At all other measurement times, the amount of TAED in each mixture did not alter the amount or speed of oxygen release (P > 0.05).

CONCLUSIONS

Tetra acetyl ethylene diamine groups achieved their maximum oxygen release 2 h earlier at 25 degrees C and 1 h earlier at 37 degrees C than the other groups. Thus, TAED accelerated oxygen release from sodium perborate-distilled water mixtures regardless of its proportions up to 24 h.

Bond strength of glass-ceramics on the fluorosed enamel surfaces

OBJECTIVES

Effect of different adhesive luting systems on the shear bond strength of IPS Empress 2 ceramic restorations to fluorosed enamel surface was investigated.

METHODS

Forty-eight ceramic discs (2 mm x 3 mm; IPS Empress 2) were fabricated. Twenty-four non-carious extracted human molar teeth with fluorosis and 24 without fluorosis were cleaned with pumice using a plastic brush and then they were divided into two main groups. The IPS Empress 2 ceramic discs were luted to the teeth of four subgroups with two different adhesive luting systems, Variolink 2/Excite DSC (etch-and-rinse) and Clearfil Esthetic Cement/ED Primer II (self-etch), thermocycling was performed 5000 times. Shear bond strengths were tested using Shimadzu Universal Testing Machine until failure. An optical microscope and image analyzer were used at 10x and 1000x magnification to analyze the surfaces for adhesive, cohesive and mixed failure percentages. Data was analyzed with one-way ANOVA and Tukey test at a significance level of p<0.05.

RESULTS

Mean shear bond strength data of the groups in MPa were; Variolink 2/Excite DSC on fluorosed enamel: 18.3+/-3.08, Variolink 2/Excite DSC on non-fluorosed enamel: 18.79+/-2.65, Clearfil Esthetic Cement/ED Primer II on fluorosed enamel: 8.43+/-2.45, Clearfil Esthetic Cement/ED Primer II on non-fluorosed enamel: 13.53+/-1.68. Mixed failure was the most prevalent type of failure in moderate fluorosed and non-fluorosed teeth with etch-and-rinse dentin bonding system, and in fluorosed teeth with self-etch dentin bonding system.

CONCLUSIONS

The use of an etch-and-rinse adhesive luting procedure produced higher bond strengths of glass-ceramics bonded to fluorosed and non-fluorosed enamel surfaces than the self-etch bonding system.

Reversal of Compromised Bonding in Bleached Enamel Using Antioxidant Gel

Dental bond strength is significantly reduced when bonding is performed immediately after bleaching treatments. It has also been reported that the application of an antioxidant after bleaching treatment improves the adhesive bond strength of oxidized enamel tissue. The application of an antioxidant in gel form by the patient makes the application process easier and shortens time spent in the clinic.

Evaluation of the shear bond strength of 3 curing bracket bonding systems combined with an antibacterial adhesive

INTRODUCTION

The purpose of this in-vitro study was to investigate the shear/peel bond strength of metal brackets bonded to human enamel with differently cured bonded systems combined with an antibacterial adhesive component.

METHODS

One hundred twenty extracted molars were divided into 3 groups. Stainless steel brackets were bonded with 1 of 3 systems: group 1, no-mix bonding adhesive (Unite, 3M Unitek, Monrovia, Calif) (n = 40); group 2, 2-paste chemically cured bonding resin (Concise, 3M Unitek) (n = 40); and group 3, light-cured adhesive (Transbond XT, 3M Unitek) (n = 40). Each bonding group was separated into experimental (n = 20) and control groups (n = 20). In the 3 experimental groups, an antibacterial self-etch adhesive (Clearfil Protect Bond, Kurary, Osaka, Japan) was also applied to the enamel. Specimens in the control groups were bonded only with their relevant bonding systems according to the manufacturers' instructions. All specimens were stored in distilled water for 24 hours and thermocycled before testing. Debonded specimens were scored with the adhesive remnant index.

RESULTS

The mean bond strengths (in megapascals) were 9.8 (control, 15.7) in group 1, 12.0 (control, 18.5) in group 2, and 11.6 (control, 12.4) in group 3. Statistical analysis with t tests showed no difference between group 3 and its control (P = .178), whereas groups 1 and 2 were statistically different from their controls (P = .000).

CONCLUSIONS

The results indicated that the newly developed antibacterial self-etch adhesive can be combined with various bonding systems; achieved bond strengths were clinically more than satisfactory.

Influence of luting agent on the microleakage of all-ceramic crowns

PURPOSE

In this in-vitro study, microleakage of all-ceramic crowns was evaluated at enamel and dentin margins.

MATERIALS AND METHODS

Forty maxillary central incisors were randomly divided into 4 groups (n = 10). While buccal and palatal margins were placed on enamel, mesial and distal margins were placed below the cementoenamel junction. In groups 1 to 3, IPS Empress 2 crowns were luted with Variolink 2/Syntac Classic (group 1), Bifix DC/Solobond Plus (group 2) and Calibra/Prime & Bond NT combinations (group 3), respectively. In the control group (group 4), porcelain-fused-to-metal crowns were luted with a zinc-phosphate cement. All specimens were subjected to 5000 thermocycles (at 5 degrees C to 55 degrees C; 30-s dwell time). After immersion in India ink for 48 h at 37 degrees C, the specimens were sectioned both buccolingually and mesiodistally. Each section was evaluated for microleakage under a stereomicroscope at 24X magnification.

RESULTS

According to the Krukal-Wallis test, in all groups, there were significant differences in microleakage at the enamel margins (p = 0.001). Nevertheless, the margins finished in dentin showed no significant differences (p = 0.163). According to the Mann-Whitney U-test, statistically significant differences were observed in microleakage between groups 1 and 3 (p = 0.049), groups 1 and 4 (p = 0.001), groups 2 and 4 (p = 0.002), and between groups 3 and 4 (p = 0.045) at the enamel margin. In group 1, significantly greater microleakage was observed at the dentin margin compared to the enamel margin (p = 0.007).

CONCLUSION

The adhesive luting technique demonstrated an excellent ability to minimize microleakage of all-ceramic crowns at the enamel margins. Water-based dentin bonding systems showed less microleakage than the water-free acetone-based dentin bonding system at the enamel margin.

Effect of antioxidant on coronal seal of dentin following sodium-hypochlorite and hydrogen-peroxide irrigation

PURPOSE

To reduce the microleakage of a self-etching priming dentin adhesive with the use of antioxidant or bur finishing after sodium-hypochlorite or hydrogen-peroxide irrigation.

METHODS

70 single-root canals were enlarged and seven different treatment protocols were applied throughout the root canal treatment: The roots in Groups 1, 2, and 3 were irrigated with sodium-hypochlorite. Group 1 was used as the negative control with only sodium-hypochlorite irrigation whereas in Group 2, sodium-ascorbate was applied as an additional irrigation agent following sodium-hypochlorite. Irrigation procedure in Group 3 was same as in Group 1, however, after the roots in this group were obturated, cavities were cleaned off with a carbide bur (bur-finishing) to remove the effect of sodium-hypochlorite. Hydrogen-peroxide irrigation was used in Groups 4, 5 and 6; the procedural steps were similar to those of Groups 1, 2 and 3: hydrogen-peroxide in Group 4, sodium-ascorbate application in Group 5, and bur-finishing in Group 6. Group 7 was the positive control with saline irrigation alone. All roots were obturated with Diaket sealer and gutta-percha cones using cold lateral condensation technique immediately after irrigation. A self-etching priming adhesive plus resin composite was applied after the endodontic treatment. The microleakage of dentin margins was determined using dye-penetration technique with clearing process.

RESULTS

The Kruskal-Wallis followed by Mann-Whitney test showed that both sodium-hypochlorite and hydrogen-peroxide deteriorated the marginal seal of the dentin adhesive (P < 0.05), however, following both irrigation solutions the use of sodium-ascorbate reduced the microleakage (P < 0.05). Additionally, when sodium-ascorbate or bur-finishing was applied to remove the deterioration caused by sodium-hypochlorite or hydrogen-peroxide, the microleakage scores obtained were not different from that of the positive control (P > 0.05).

Shear bond strength of different adhesives to Er:YAG laser-prepared dentin

PURPOSE

The aim of this study was to examine the influence of Er:YAG laser on the shear bond strength of three different adhesives to lased dentin.

MATERIALS AND METHODS

Seventy specimens obtained from 35 extracted human molars were embedded in polyester resin and ground with silicon carbide papers. The samples were divided into seven groups. 1. Er:YAG laser (Key Laser 3, KaVo) + Clearfil Protect Bond (Kuraray); 2. Er:YAG laser + Clearfil tri-S Bond (Kuraray); 3. Er:YAG laser + 37% H3PO4 + Single Bond 2 (3M-ESPE); 4. Er:YAG laser + Single Bond 2; 5. conventional method + Clearfil Protect Bond; 6. conventional method + Clearfil tri-S Bond; 7. conventional method + 37% H3PO4 + Single Bond 2. The samples were subjected to shear bond testing 24 h after bonding. Statistical analyses were carried out by two-way ANOVA, t-test, one-way ANOVA, post-hoc Tukey's and Dunnett C test (p = 0.05).

RESULTS

Only the Er:YAG laser + Clearfil tri-S Bond group demonstrated significantly higher bond strengths vs conventionally prepared specimens (p < 0.05). There were no significant differences between the shear bond strengths of Single Bond 2 adhesive applied to laser- vs bur-treated specimens (p > 0.05). In laser prepared samples, Clearfil Protect Bond showed the highest scores (p < 0.05), whereas in conventionally prepared groups, no statistical differences were observed between Clearfil Protect Bond and Clearfil tri-S Bond (p > 0.05).

CONCLUSION

Er:YAG laser irradiation did not adversely affect the shear bond strength of Single Bond 2 and Clearfil Protect Bond to dentin, whereas it increased the shear bond strength values of Clearfil tri-S Bond.

Is an antibacterial adhesive system more effective than cavity disinfectants?

PURPOSE

To compare the antibacterial activity of an adhesive system containing an antibacterial monomer MDPB, Clearfil Protect Bond with three different cavity disinfectants, chlorhexidine gluconate-based Consepsis, benzalkonium chloride-based Tubulicid Red and 3% hydrogen peroxide.

METHODS

Materials were tested using agar well technique and a tooth cavity model. The test materials were filled in the agar wells of plates inoculated with Streptococcus mutans. After 48 hours of incubation, the zones of inhibitions were measured in millimeters. For the tooth cavity model test, cylindrical cavities were prepared in the flat occlusal dentin of human extracted molars. The teeth were left in a broth culture of Streptococcus mutans at 37 degrees C for 72 hours allowing bacteria to invade. Teeth were then randomly assigned into five groups of five teeth (10 cavity preparations) each. In the first four groups test materials were applied into the cavities following the manufacturer's instructions and the cavities in the fifth group were left untreated for control. The teeth were kept in saline for 72 hours. Standard amounts of dentin chips were obtained from the cavity walls and the number of bacteria recovered was counted.

RESULTS

The results were analyzed by ANOVA, Dunnett C and Bonferroni tests. For the agar well technique, Clearfil Protect Bond primer exhibited greater inhibition zones than all three cavity disinfectants (P< 0.05). When tested by the cavity method, the application of Clearfil Protect Bond system resulted in significantly less bacterial recovery than all disinfectants (P< 0.05). For both microbiological methods, there were no significant differences between the antibacterial activities of Consepsis and Tubulicid Red (P> 0.05). They were superior to hydrogen peroxide in the cavity test method (P< 0.05).

Bactericidal effect of Er,Cr:YSGG laser on Streptococcus mutans

The aim of this study was to compare the antibacterial activities of Er,Cr:YSGG laser with two different power outputs against a chlorhexidine gluconate-based cavity disinfectant. A cavity tooth model test was used to determine the antibacterial activity. Four cylindrical cavities were prepared on the dentin surface of 10 bovine incisors and left in contact with Streptococcus mutans for 72 hours to allow bacterial invasion. Following which, Er,Cr:YSGG laser with 0.75 W and 1 W power outputs and a chlorhexidine gluconate-based cavity disinfectant were applied separately on one of the three infected cavities, whereas the fourth was left untreated for control. Standardized amounts of dentin chips were obtained from the cavity walls, and the number of bacteria recovered was counted. Statistical analysis was carried out using one-way ANOVA and Dunnett's C test (p=0.05). No significant differences were observed among the data obtained from the chlorhexidine gluconate-based cavity disinfectant and the two Er,Cr:YSGG laser groups (p>0.05). However, when compared to the control group, both Er,Cr:YSGG laser groups and the chlorhexidine gluconate-based cavity disinfectant resulted in significantly less bacterial recovery (p<0.05). In conclusion, the antibacterial activity on S. mutans demonstrated by Er,Cr:YSGG laser with both energy outputs was similar to that of the tested chlorhexidine gluconate-based cavity disinfectant.

Effect of an antibacterial adhesive on the bond strength of three different luting resin composites

OBJECTIVES

Effect of a dentin adhesive system containing antibacterial monomer-MDPB (Clearfil Protect Bond) on the shear bond strength of all-ceramic-IPS Empress 2 restorations luted with three different dual-polymerizing systems (Variolink 2, RelyX ARC and Panavia F 2.0) to dentin was investigated.

METHODS

One hundred and eight all-ceramic discs (2 x 3mm; IPS Empress 2) were fabricated and ultrasonically cleaned. The buccal surfaces of 108 non-carious extracted human premolars were flattened to expose dentin and subsequently polished with 600-grit wet silicon carbide paper. Three dual-polymerizing luting systems had test groups and control groups consisting of 18 samples each. For the test groups Clearfil Protect Bond was applied to the exposed dentin surfaces. Control groups received the original bonding procedures of each adhesive system. After the all-ceramic samples were luted to the teeth, thermocycling was performed 5000 times. Shear bond strengths were tested using Shimadzu Universal Testing Machine until failure. Analysis of fractured dentin surfaces were performed using Optical Microscope at x10 and x1000 magnifications and the images were analyzed with Image Analyzer. Data was analyzed with one-way ANOVA and Bonferroni test at a significance level of p<0.05.

RESULTS

Mean shear bond strength data of the groups in MPa were; Variolink: 20.45+/-4.75, Variolink+Clearfil Protect Bond:29.32+/-2.37, RelyX ARC:18.82+/-3.19, RelyX ARC+Clearfil Protect Bond:25.58+/-4.05, Panavia F 2.0:17.11+/-2.98, Panavia F 2.0+Clearfil Protect Bond:24.40+/-7.46. Application of the antibacterial adhesive increased the shear bond strengths of all three dual-polymerizing systems to dentin (p=0.00). The surface analysis showed that most of the specimens showed the adhesive failure mode between the dentin and the composite luting agent interface.

CONCLUSION

The antibacterial adhesive system Clearfil Protect Bond can be safely used to prevent the potential risk of complications resulting from bacterial activity regardless of affecting the bond strength of IPS Empress 2 restorations luted with the dual-polimerizing systems used in this study.

Effect of endodontic irrigants on microleakage of coronal restorations

PURPOSE

To evaluate the effect of endodontic irrigants on the sealing ability of resin composite coronal restorations bonded with two different bonding systems, Clearfil SE Bond and PQ1.

METHODS

The specially designed coronal preparations with distal margins on dentin and mesial margins on enamel were performed on 100 single-rooted teeth. They were initially divided into five groups. Irrigants used during the root canal preparation in each group were as follows: sodium hypochlorite, hydrogen peroxide, Tubulicid Plus, Cetrexidin and saline (control). After root canal filling, each irrigation group was divided into two bonding groups. Following the placement of the composite restorations, the specimens were immersed in India ink and cleared to allow visualization of the leakage.

RESULTS

The differences among the irrigation groups were statistically significant only at margins remaining on dentin structures for both of the bonding resins (P< 0.05). Sodium hypochlorite, hydrogen peroxide groups demonstrated higher leakage scores than the controls (P< 0.005). Leakage patterns of Cetrexidin and Tubulicid Plus groups did not differ significantly from the controls (P> 0.005). Cetrexidin allowed better sealing than Tubulicid Plus in PQ1 bonded restorations, but did not in Clearfil SE Bond samples.

Clinical performance of a packable resin composite for a period of 3 years

OBJECTIVE

The purpose of this clinical study was to evaluate SureFil packable resin composite for posterior restoration of permanent teeth for a period of 3 years.

METHOD AND MATERIALS

Fifty-five resin composite restorations were placed in 36 patients (16 Class I and 39 Class II restorations). After cavity preparation, the enamel was etched with 34% phosphoric acid. Prime & Bond NT was applied 20 seconds to dentin and etched enamel and cured for 20 seconds. The teeth were restored in 3- to 5-mm increments. The restorations were assessed after placement, at 6 months, 1 year, 2 years, and 3 years for color stability, marginal discoloration, marginal adaptation, secondary caries, surface texture, anatomic form, and postoperative sensitivity according to Ryge's criteria. The changes in the parameters were assessed with Friedman test analysis with a Bonferroni correction at a significance level of .05.

RESULTS

Forty of the monitored 47 restorations were classified as excellent after 3 years. Thirty-one restorations were graded Bravo at baseline for color match. At the 3-year assessment (n = 47) the color of the 31 restorations had not changed. Two restorations (same patient) were lost after 1 month and were scored as Charlie until the end of the study. After 3 years there were five Bravos and one Charlie with marginal discoloration, five Bravos with marginal adaptation, and three Bravos with anatomic form (P < .05).

CONCLUSION

After 3 years of clinical service, SureFil packable resin composite, with a failure rate of 6%, was considered to be successful in Class I and II restorations.

Factors affecting microleakage of a packable resin composite: an in vitro study

This study was designed to determine the effects of three factors on the microleakage of a packable resin composite: different adhesive systems (single-step self-etching adhesive or total-etch and one-bottle adhesive), the use of a flowable resin composite (as a liner) and the different techniques of cavity preparation. Sixty extracted non-carious human first and second molars were selected and randomly divided into six groups. Cervical cavities were prepared using the conventional technique on the distal sides and the air-abrasive technique was used on the mesial sides of the teeth. The experimental groups were restored with PQ1 + SureFil or Prompt L-Pop + SureFil with or without PermaFlo. In the control groups, only SureFil was used on 10 teeth and PermaFlo + SureFil was applied on the remaining 10 teeth. The restored teeth were stored in 100% humidity at 37 degrees C for 24 hours and thermocycled between 5 degrees C and 55 degrees C for 100 cycles. Each tooth was immersed in India ink for 48 hours, then sectioned. Dye penetration at the occlusal and gingival margins was scored by two independent operators. The data were statistically analyzed to assess the differences between the test and control groups. No significant differences among the adhesives in terms of the occlusal margins of the cavities were observed. However, PQ1 led to less microleakage compared to Prompt L-Pop at the gingival margins (p < 0.0062). When flowable resin composite was used with Prompt L-Pop, microleakage was reduced (p < 0.0125). However, no significant difference was observed between the two cavity preparation techniques (p > 0.0125).

Antibacterial activity of two adhesive systems using various microbiological methods

PURPOSE

To compare the antibacterial activities of two dentin bonding systems (DBS), Clearfil Protect Bond and Xeno III, by agar well, paper and dentin disks, and a cavity tooth model.

MATERIALS AND METHODS

For the well technique, the test materials were filled in the agar wells inoculated with Streptococcus mutans (ATCC 25175). The paper disks were embedded in adhesives and placed on the seeded agar plates for the second technique. The adhesives were applied on the dentin disks and placed in holes in the plates for the third technique. After 48 h, the zones of inhibition were measured. In the cavity tooth model test, 3 cavities were prepared in the flat occlusal dentin of extracted human molars. The teeth were left in S. mutans for 72 h to allow bacterial invasion. The DBS were applied in the same manner as in clinical application on each of the two infected cavities and the third was left unapplied for control. The teeth were kept in saline for 72 h. Standard amounts of dentin chips were obtained from the cavity walls and the number of bacteria recovered was counted.

RESULTS

The results were analyzed by factorial ANOVA and Dunnett C test. Clearfil Protect Bond primer exhibited the greatest inhibition zones followed by Consepsis and unpolymerized Xeno III in all the techniques tested (p < or = 0.05). Clearfil Protect Bond resulted in significantly less bacterial recovery than Xeno III by the tooth cavity method (p < or = 0.05).

CONCLUSION

Clearfil Protect Bond was found to be the most antibacterial material with all the techniques used. Furthermore, Clearfil Protect Bond was able to inactivate the bacteria in the cavity more effectively than Xeno III.

Effect of 10% sodium ascorbate on the shear bond strength of composite resin to bleached bovine enamel

The purpose of this study was to comparatively investigate the effect of antioxidant treatment and delayed bonding after bleaching with three different concentrations of carbamide peroxide (CP) on the shear bond strength of composite resin to enamel. One hundred flat buccal enamel surfaces obtained from bovine incisors were divided into three bleaching groups of 10, 16 and 22% CP (n = 30) and a control group. Each bleaching group was then divided into three subgroups (n = 10). Group 1 consisted of specimens bonded immediately after bleaching. Group 2 specimens were treated with antioxidant agent, 10% sodium ascorbate, while Group 3 specimens were immersed in artificial saliva for 1 week after bleaching. Specimens in the control group were not bleached. After the specimens were bonded with Clearfil SE Bond and Clearfil AP-X, they were thermocycled and tested in shear until failure. Fracture analysis of the bonded enamel surface was performed using scanning electron microscope. The shear bond strength data was subjected to one-way analysis of variance followed by Duncan's multiple range test at a significance level of P < 0.05. Shear bond strength of composite resin to enamel that was bonded immediately after bleaching with 10, 16 and 22% CP was significantly lower than that of unbleached enamel (P < 0.05). For all three bleaching groups, when the antioxidant-treated and delayed bonding (1 week) subgroups were compared with the control group, no statistically significant differences in shear bond strength were noted (P < 0.05).

Effect of Bleaching and Repolishing Procedures on Coffee and Tea Stain Removal from Three Anterior Composite Veneering Materials

Discolored teeth can be treated with resin veneers, but their color changes when confronted with staining solutions. Polishing procedures can provide a remedy for highly stained composites, but they tend to remove some materials as well. However, bleaching procedures are an effective, nondestructive method for solving the problem. The aim of this study was to compare the color change of three veneer composites exposed to staining solutions and to evaluate the effectiveness of a 15% hydrogen peroxide bleaching agent and three polishing systems to remove the stain. Forty-five disks (12 x 2 mm) each of Clearfil ST (Kuraray Co. Ltd., Osaka, Japan), Esthet-X (Dentsply/Caulk, Milford DE, USA), and Filtek A110 (3M ESPE, St. Paul, MN, USA) were prepared. The specimens were polished with Sof-Lex (3M ESPE), Enhance (Dentsply/Caulk), or PoGo (Dentsply/Caulk). Five specimens for each material-polishing system combination were immersed in coffee (Nescafe Classic, Nestle SA, Vevey, Switzerland) or tea (Earl Grey, Lipton, Blackfriars-London, England) for 7 days. The remaining disks were stored in water. Color measurements were made with a spectrophotometer (X-Rite Seroice SP78, Loaner, Köln, Germany) at baseline; after 1, 3, 5, and 7 days; and after bleaching and repolishing. After 1 week, one side of the specimens was bleached with Illuminé-office (Dentsply De Trey GmbH, Konstanz, Germany) for 1 hour, and the other side was repolished for 30 seconds. All comparisons of color change for the polishing systems, times, and staining solutions were subjected to repeated measurements of analysis of variance. Paired t-test was used to examine whether significant color differences (deltaE*) occurred during immersion at the specified time intervals (p < or = .05). Filtek A110 was the least stained resin composite. Its color remained under a deltaE* value of 2 during the study. Clearfil ST exhibited the most color change after 1 week. All specimens polished with Enhance showed less staining, whereas those polished with the Sof-Lex system demonstrated the most color change. Water did not cause a variance in the deltaE*. There was no difference in the staining potential of coffee and tea. Bleaching and repolishing were effective in removing the stains. The resin composites tested reversed nearly to baseline color with the bleaching and to less than values at 1 day of staining with repolishing. The coffee and tea brands tested stained the composites used in this study equally. In-office bleaching was found to be more effective than repolishing in the restitution of the color.

CLINICAL SIGNIFICANCE

The results of this study suggest that the discoloration of resin veneers can be partially removed by in-office bleaching and repolishing procedures.

Esthetic enhancement of ceramic crowns with zirconia dowels and cores: a clinical report

There has been an increase in the use of esthetic metal-free ceramic crowns in restoring endodontically treated teeth or teeth with severe coronal destruction. Tooth-colored dowels and cores are used to enhance the esthetic result. This report describes the treatment of a patient with bilateral maxillary supernumerary lateral incisors, a severe malocclusion, and maxillary anterior tooth discoloration. Treatment included heat-pressed, metal-free ceramic crowns supported by zirconia ceramic dowel-and-core foundations.

Effect of cavity disinfectants on the sealing ability of nonrinsing dentin-bonding resins

OBJECTIVES

The purpose of this study was to determine the effect of three cavity disinfectants (chlorhexidine gluconate-based, Consepsis; benzalkonium chlorite-based, Tubulicid red; iodine-potassium iodide/copper sulphate-based, Ora-5) on the microleakage of nonrinsing dentin-bonding systems, Clearfil SE Bond and Prompt L-Pop.

METHOD AND MATERIALS

Class V cavity preparations were placed on the buccal and lingual surfaces of extracted molars with occlusal margins at the enamel and gingival margins in cementum. In the experimental groups, cavities were treated with combinations of one of the three cavity disinfectants with either Clearfil SE Bond or Prompt L-Pop. The preparations without disinfectant application were used as the negative controls for each adhesive system, and the cavities in which neither disinfectant nor dentin-bonding resin were applied, served as the positive controls. After the cavity preparations were restored with resin composite, specimens were thermocycled, stained, and sectioned to evaluate dye penetration. The tooth-resin composite interface of the sectioned specimens was examined under scanning electron microscopy.

RESULTS

Consepsis and Tubulicid red did not significantly affect the sealing ability of Clearfil SE Bond and Prompt L-Pop. Ora-5 exhibited gap formations at the tooth-resin composite interface and produced significantly higher microleakage when used with these bonding systems.

CONCLUSION

Consepsis and Tubulicid red can be used as cavity disinfectants with Clearfil SE Bond and Prompt L-Pop without affecting their sealing abilities. However, Ora-5 is not an appropriate disinfectant to use with these bonding systems.

The effect of one-step polishing system on the surface roughness of three esthetic resin composite materials

Proper finishing of restorations is desirable not only for aesthetic considerations but also for oral health. The primary goal of finishing is to obtain a restoration that has good contour, occlusion, healthy embrasure forms and a smooth surface. This study investigated: 1) analyzing the surface roughness of three resin composites finished and polished with a new one-step and two conventional multi-step polishing systems and 2) evaluating the effectiveness of one-step polishing system and surface morphology using scanning electron microscope analysis (SEM). Specimens (N = 72) measuring 8-mm in diameter x 2-mm in thickness were fabricated in a plexiglass mold covered with a Mylar strip using three esthetic resin composites. After polymerization six specimens per resin composite received no finishing treatment and served as a control. Fifty-four specimens were randomly polished with Sof-Lex discs, Enhance disc with polishing paste or PoGo for 30 seconds after being ground wet with a 1200 grit silicon carbide paper. The average surface roughness of each polished specimen was determined with a profilometer (Surtronic 4). The data were analyzed using repeated measures ANOVA and Scheffe's post-hoc test of multiple comparisons (p < or = 0.01). Representative samples of the mentioned finishing procedures were selected and examined using a scanning electron microscope (SEM). There was no surface roughness in all resin composites tested against Mylar strip. The results showed no difference between the surfaces of Clearfil ST and Esthet-X polished with PoGo and the Mylar group (p > or = 0.01). Among all the polishing systems tested, PoGo exhibited the smoothest finish for all resin composites. The combination of Enhance and Prisma Gloss polishing paste exhibited the highest roughness values for Filtek A110 and Clearfil ST; however, it gave the same Ra values as PoGo for Esthet-X (p < or = 0.01). SEM analysis of Esthet-X samples confirmed the profilometer's results. The surfaces of the Clearfil ST discs polished with PoGo resemble that of Mylar, while Enhance and Sof-Lex exposed and dislodged the filler particles. PoGo scratched in some places Filtek A110's surface, while Enhance produced mostly a Mylar-like surface with dislodged fillers in some places.

Amelogenesis imperfecta: the multidisciplinary approach. A case report

Amelogenesis imperfecta is a hereditary developmental disorder of the dental enamel, in both primary and permanent dentition. The main clinical characteristics are extensive loss of tooth tissue, poor esthetics, and tooth sensitivity. Transmission of the gene takes place by either autosomal, dominant X-linked, or recessive modes. This clinical report describes a treatment sequence based on a multidisciplinary approach. A 21-year-old girl with hypoplastic amelogenesis imperfecta was referred to the Ege University School of Dentistry clinic. She was concerned about the poor appearance and sensitivity of her teeth. The patient presented with an anterior open bite, although orthodontic treatment had been completed previously. Periodontal gingivectomy of her posterior teeth followed by endodontic treatment where indicated was proposed. The prosthodontic treatment consisted of metal ceramic fixed partial dentures of precious alloy. At the end of treatment, function and esthetics were improved to a level acceptable to both the patient and the dental team.

Effect of nonvital bleaching with 10% carbamide peroxide on sealing ability of resin composite restorations

AIM

To (i) determine the effect of nonvital bleaching with 10% carbamide peroxide on the sealing ability of resin composite restorations bonded with a self-etching adhesive system; and (ii) compare the effects of antioxidant treatment and delayed restoration after bleaching on marginal seal.

METHODOLOGY

Forty-eight noncarious maxillary incisors were divided into four groups (n=12) after conventional root canal treatment was completed. In group 1, access cavities were restored with a self-etching adhesive system and resin composite. In the remaining three groups, 10% carbamide peroxide bleaching gel was placed into the access cavities for periods of 8 h per day for 1 week. They were then restored in the same manner as group 1. Group 2 consisted of specimens restored immediately after bleaching. Group 3 specimens were treated with the antioxidant, 10% sodium ascorbate, whereas group 4 specimens were immersed in artificial saliva for 1 week before restoration. Ten specimens in each group were then subjected to dye leakage; the remaining 2 specimens were examined in a SEM (Jeol/JSM 5200, Tokyo, Japan). The dye penetration was assessed with the standard scoring system. Statistical analysis was carried out using the Kruskal-Wallis and the Mann-Whitney tests.

RESULTS

Groups 1, 3 and 4 exhibited similar leakage patterns and significantly less leakage than group 2 (P<0.0083). SEM examination of groups 1, 3 and 4 specimens demonstrated close adaptation of resin composite to cavity walls, whereas group 2 specimens did not.

CONCLUSION

Nonvital bleaching with 10% carbamide peroxide adversely affected the immediate sealing ability of resin composite restoration; both 10% sodium ascorbate treatment and a 1-week delay in restoration following bleaching improved the reduced sealing ability of resin composite.

Reversal of dentin bonding to bleached teeth

Many studies have shown a considerable reduction in enamel bond strength of resin composite restorations when the bonding procedure is carried out immediately after bleaching. These studies claim that a certain waiting period is needed prior to restoration to reach the original bond strength values prior to bleaching. This study determined the effect of anti-oxidant applications on the bond strength values of resin composites to bleached dentin. Ninety human teeth extracted for orthodontic purposes were used in this study. The labial surface of each tooth was ground and flattened until dentin appeared. The polished surfaces were subjected to nine different treatments: 1) bleaching with gel (35% Rembrandt Virtuoso); 2) bleaching with gel + 10% sodium ascorbate (SA); 3) bleaching with gel + 10% butylhydroxyanisole (BHA); 4) bleaching with sol (35% hydrogen peroxide); 5) bleaching with sol + 10% sodium ascorbate; 6) bleaching with sol + 10% BHA; 7) bleaching with gel + immersed in artificial saliva for seven days; 8) bleaching with sol + immersed in artificial saliva for seven days; 9) no treatment. After bonding application, the resin composite in standard dimensions was applied to all specimens. The teeth were stored in distilled water at 37 degrees C for 24 hours and a universal testing machine determined their resistance to shear bond strength. The data was evaluated using ANOVA and Duncan tests. Bond strength in the bleached dentin group significantly decreased compared to the control group. On the other hand, the antioxidant treatment had a reversal effect on the bond strength to dentin. After the bleaching treatment, the 10% sodium ascorbate application was effective in reversing bond strength. In the samples where antioxidant was applied after the bleaching process, bonding strength in dentin tissue was at the same level as those teeth kept in artificial saliva for seven days.

Two-year clinical evaluation of a packable resin-based composite

BACKGROUND

Packable resin-based composites were introduced in 1998, but few clinical studies have been conducted to evaluate them. The authors conducted a clinical study to determine the two-year performance of SureFil (Dentsply DeTrey GmbH, Konstanz, Germany) packable posterior resin-based composite in Class I and II restorations.

METHODS

An operator (L.S.T.) restored 55 cavities in 36 patients (16 Class I restorations and 39 Class II restorations). After cavity preparation, she etched the enamel with 34 percent phosphoric acid, applied Prime & Bond NT (Dentsply DeTrey GmbH) to dentin and etched enamel for 20 seconds and then cured it for 20 seconds. She restored the cavity using 3- to 5-millimeter increments of SureFil. Independent examiners assessed the restorations after placement and at six months, one year and two years for color matching, marginal discoloration, marginal adaptation, secondary caries, surface texture, anatomical form and postoperative sensitivity, using the Ryge criteria.

RESULTS

The authors assessed the changes in the parameters during the two-year period using a software program with Friedman test analysis with a Bonferroni adjustment at significant level of P = .05. At baseline, 31 restorations were graded as Bravo for color match. At the six-month and one-year recall periods (n = 55), 53 restorations remained unchanged. Two restorations from the same patient fell out after one month. After two years (n = 50), there were five Bravos for surface staining and three for marginal adaptation (P < .05).

CONCLUSION

After two years of clinical service, SureFil packable resin-based composite had a success rate of 96 percent, and the authors considered it successful in Class I and II restorations.

CLINICAL IMPLICATIONS

SureFil packable resin-based composite can be successful in clinical situations with limited-sized cavities and proper application of restorative techniques.

Delayed replantation of avulsed mature teeth with calcium hydroxide treatment

Three avulsed teeth that were replanted and splinted after approximately a 200-min dry extraoral period in two patients are presented. In case 1 calcium hydroxide treatment was performed 1 month after replantation, because the patient did not come for endodontic treatment on the day after replantation as requested. In case 2, calcium hydroxide treatment was initiated on the day after replantation. Calcium hydroxide treatment was used to prevent or treat inflammatory root resorption. During the follow-up periods the teeth reported in these cases have remained in a stable, functional position and did not reveal clinical ankylosis or replacement resorption.

Surgical extrusion of crown-root-fractured teeth: a clinical review

AIM

In this clinical study combined surgical and endodontic treatment was performed in 20 cases of crown-root fracture and the outcomes reviewed.

METHODOLOGY

Surgical treatment involved a conventional extraction and stabilization technique. Root canal treatment using calcium hydroxide was performed. Before root canal obturation, a calcium hydroxide dressing was maintained for 3 months.

RESULTS

Follow-up examinations, which varied between 6 and 36 (mean 14.5) months, showed that there were no radiographic and clinical signs of progressive root resorption, marginal bone loss or periapical disease in all except one case.

CONCLUSIONS

The favourable results of this study demonstrate that surgical extrusion in teeth with crown-root fractures may be an alternative treatment to orthodontic extrusion.

Surgical extrusion of intruded immature permanent incisors: case report and review of the literature

This report presents a case of intrusive luxation of immature maxillary central incisors with concomitant uncomplicated crown fractures in an 8-year-old boy. The intruded teeth with open apices were repositioned with surgical extrusion and endodontically treated through use of calcium hydroxide paste. Six months after initiation of apexification, definitive apical stops had formed. The canals were then permanently obturated, and the crowns were restored with composite resin. Clinical and radiographic examination 24 months after the surgical extrusion revealed satisfactory apical healing and healthy supporting tissues.

Effect of calcium hydroxide as an intracanal dressing on apical leakage

In this in vitro study, we investigated the effects of the use of two different calcium hydroxide (Ca(OH)2) preparations as an intracanal dressing on the sealing ability of two different sealers were investigated. Eighty-eight freshly extracted, single-rooted maxillary anterior teeth were used. After the root canals were hand-instrumented, they were divided into six groups of 10 each. The root canals were dressed with Ca(OH)2 paste, either mixed with sterile water (in groups 1 and 2) or with glycerine (in groups 3 and 4). The dressed root canals were incubated in 100% humidity at 37 degrees C for 7 days. In groups 5 and 6, the root canals were not dressed. After the root canal dressings were removed by irrigation with 5.25% NaOCl and reaming with a K-type file, all canals of the experimental groups were obturated with sealer and gutta-percha using a cold lateral condensation technique. Calciobiotric Root Canal Sealer, (CRCS), (in groups 1, 3 and 5) and Diaket (in groups 2, 4 and 6) were used as sealers. All specimens were placed in India ink for 7 days, and the amount of apical leakage was scored. Eight further prepared specimens were dressed with Ca(OH)2 plus water or Ca(OH)2 plus glycerine and examined with scanning electron microscopy (SEM) following the removal of dressings. There was a statistical difference in the leakage patterns amongst the 6 experimental groups (P < 0.05). Specimens in group 2 exhibited less leakage than the other experimental groups, except group 4 (P < 0.05). There were no other significant interactions. SEM examination revealed that Ca(OH)2 crystals were present on the surface of smear layer in both groups where Ca(OH)2 paste had been placed, but they did not penetrate into the dentinal tubules.

Delayed endodontic and orthodontic treatment of cross-bite occurring after luxation injury in permanent incisor teeth

A case is presented in which combined endodontic and orthodontic therapy was performed in traumatically injured teeth 12 months after an accident. Calcium hydroxide treatment was used to halt any possible resorption during orthodontic treatment. The teeth were repositioned in a desirable manner without any complication by orthodontic treatment. Root canal obturation was accomplished after the completion of active orthodontic treatment. Recall examination 12 months after completion of root canal treatment showed clinical and radiographic evidence of healing.

Periapical repair and apical closure of a pulpless tooth using calcium hydroxide

A case with a wide-open apex and a large cystlike periapical lesion in an adult is presented. The lesion formed as a result of necrosis from trauma to a maxillary central incisor 12 years ago. After nonsurgical endodontic treatment with calcium hydroxide paste and a calcium hydroxide-containing root canal sealer, apical closure and significant healing of the periapical lesion within 15 months were observed. This report suggests that even large periapical lesions (likely cystic) could respond favorably to nonsurgical treatment.

The effects of sodium hypochlorite and calcium hydroxide on tissue dissolution and root canal cleanliness

In this in vitro study, we investigated the efficacy of sodium hypochlorite (NaOCl) and calcium hydroxide (Ca(OH)2) in dissolving necrotic tissue and cleaning root canals. In the first part of the study, 0.5% NaOCl solution and Ca(OH)2 paste and solution were tested with samples of necrotic bovine muscle in different treatment modes and for different periods. The necrotic tissue was weighed before and after the test and the percentage of weight change calculated. In the second part of the study, 40 extracted single-rooted human teeth were hand instrumented and then subjected to different irrigation regimens. The cleansing efficacy in root canals of 0.5% NaOCl with Ca(OH)2 pretreatments and ultrasonics was examined using scanning electron microscopy. A solution of 5% NaOCl was significantly more effective than 0.5% NaOCl as a solvent of necrotic tissue. Calcium hydroxide was an effective solvent for necrotic tissue as a paste but not as a solution. Pretreatment of necrotic tissue with Ca(OH)2 increased its solubility in 0.5% NaOCl. While 5% NaOCl plus ultrasonic irrigation produced cleaner root-canal walls at the middle and apical thirds, 0.5% NaOCl used with the same technique achieved no root-canal cleaning. However, pretreatment of root canals with Ca(OH)2 paste increased the effectiveness of 0.5% NaOCl plus ultrasonic irrigation, except in the coronal third of the root canal.

Prognosis of permanent teeth with internal resorption: a clinical review

This study was performed in order to report the clinical features of internal resorption cases and evaluate their prognosis after endodontic treatment. Twenty-seven patients with 28 teeth with internal resorption were referred to our clinic and 20 teeth were treated endodontically. Sixteen teeth had non-perforating internal resorption and were treated by conventional root canal therapy. The remaining 4 teeth had perforating internal resorption and were initially treated by remineralization therapy with calcium hydroxide. The teeth treated by conventional root canal therapy showed clinical and radiographic evidence of healing. However, the remineralization therapy was successful in only one case. The three failed cases were subsequently treated by endodontic surgery. The surgical therapy was unsuccessful in one case due to extensive loss of marginal alveolar bone and increased tooth mobility.

Root canal treatment of a root-fractured incisor tooth with internal resorption: a case report

A case is described in which root canal treatment with calcium hydroxide was used successfully to repair a fracture site with internal resorption of the tooth.

Clinical investigation of traumatic injuries of permanent incisors in Izmir, Turkey

470 injured teeth of 370 patients who consulted the Dental Clinic of Ege University, Izmir, Turkey for examination or treatment between 1981-1993 were evaluated. Information concerning sex, age of patients at the time of injury, cause of trauma, number of injured teeth, type of tooth and type of trauma were recorded. More boys suffered traumatic injuries (64.8%) than girls (35.2%). Patients aged 11-15 years old exhibited the highest number of injuries (34.4%) followed by the 6-10 years old group (24.5%). Most injuries involved one tooth (60%) and maxillary central incisors were the most often affected teeth (66.2%). The leading cause of injury was undefined falls (45.1%). At the initial examination, cases seen after a long posttraumatic period showed more complications than those presented within a short time period. Educational programs about the importance of dental trauma, the benefits of immediate attendance and conservation of avulsed and fractured teeth would be very helpful for patients. Additionally improving the knowledge of the dental practitioner about trauma would be another important point in solving the problem.

Stability of various sodium hypochlorite solutions

Although the manufacturers use at least a 2-yr expiration date for sealed undiluted NaOCl solutions, chemical stability of NaOCl may be adversely affected by many factors. The purpose of this study was to investigate the effects of storage temperature, concentration, and time on the stability on three different brands of commercial household bleaching agents as a source of NaOCl, and to compare the stability of these brands. All solutions showed degradation versus time; however, this degradation occurred very slowly except for the group of solutions containing 5% available chlorine stored at 24 degrees C. Solutions containing 0.5% available chlorine stored at 4 degrees C and 24 degrees C and 5% solutions stored at 4 degrees C showed satisfactory stability at 200 days. No significant difference was found among three brands in respect to their chemical stability.

The smear layer: a phenomenon in root canal therapy

When the root canals are instrumented during endodontic therapy, a layer of material composed of dentine, remnants of pulp tissue and odontoblastic processes, and sometimes bacteria, is always formed on the canal walls. This layer has been called the smear layer. It has an amorphous, irregular and granular appearance under the scanning electron microscope. The advantages and disadvantages of the presence of smear layer, and whether it should be removed or not from the instrumented root canals, are still controversial. It has been shown that this layer is not a complete barrier to bacteria and it delays but does not abolish the action of endodontic disinfectants. Endodontic smear layer also acts as a physical barrier interfering with adhesion and penetration of sealers into dentinal tubules. In turn, it may affect the sealing efficiency of root canal obturation. When it is not removed, the durability of the apical and coronal seal should be evaluated over a long period. If smear layer is to be removed, EDTA and NaOCl solutions have been shown to be effective, among various irrigation solutions and techniques, including ultrasonics, that have been tested. Once this layer is removed, it should be borne in mind that there is a risk of reinfecting dentinal tubules if the seal fails. Further studies are needed to establish the clinical importance of the absence or presence of smear layer.

Root canal morphology of human permanent teeth in a Turkish population

An in vitro study was performed to determine the number and the type of root canals, their ramifications, transverse anastomoses, apical foramina locations, and frequency of apical deltas in a Turkish population. One thousand four hundred human permanent teeth were injected with India ink, decalcified, and cleared after the length of each was measured. The examination of root canal systems of the teeth was based on Vertucci's classification. The findings were used to classify the teeth into four groups. Variable root canal configurations were found in the second premolar and the mesiobuccal roots of first and second molars among the maxillary teeth and in all of the mandibular teeth, except the mandibular second premolar.

Allergy to sodium hypochlorite during root canal therapy: a case report

Sodium hypochlorite (NaOCl), is the most popular irrigation solution used in root canal treatment but it is known to be an irritant to vital tissues. There have been many case reports dealing with toxic effects of this material. Although the allergic potential of NaOCl has been described in the medical literature, only one case of known hypersensitivity to NaOCl has been reported in the dental literature. In this paper a case is presented, describing both local and systemic adverse tissue reactions, caused by an allergic response, after NaOCl irrigation.

Permeability of protective gloves used in dental practice

Two brands of latex rubber gloves and one brand of polyvinyl chloride glove were examined for their permeability. New and used gloves were included. All of the gloves were examined visually and then subjected to an air leakage test, an electrical test, and a microbiologic test. Permeability was evaluated independently by two researchers in a blind manner. Statistical analysis showed that there were no significant differences among the three brands of gloves or with respect to the usage periods, according to visual inspection and the air leakage test. Conversely, there were significant differences among each of the three brands of gloves and with respect to usage periods, according to the electrical and microbiologic tests.