Accuracy of different electronic apex locators in determination of minimum Root perforation diameter

This study aims to evaluate the ability of Raypex 6, Propex Pixi, Dentaport ZX, Apex ID, Propex II and Dr.'s Finder NEO to detect minimum root canal perforation diameter. One hundred single-rooted, extracted human teeth were artificially perforated by 5 burs in different diameters (0.25-1.25 mm) in 5 mm above the apex. Twenty teeth were assigned to each group. The actual canal lengths (AL) were measured under stereomicroscope followed by a measurement of electronic canal length (EL) using each electronic apex locator (EAL). None of the EALs were able to detect the perforation at diameters of 0.50 and 0.25 mm. Although all EALs used in our study were unable to detect perforations at diameters of 0.5 mm and 0.25 mm, they were highly successful in the determination of simulated root perforations at diameters of 1.25, 1 and 0.75 mm.

Shear bond strength of resin-modified glass ionomer cement bound to mineral trioxide aggregate after various disinfection protocols

This study compared the effects of 3 different cavity disinfection protocols (CDP) on the shear bond strength (SBS) of resin-modified glass ionomer cement (RM-GIC) to mineral trioxide aggregate (MTA). One hundred eighty standard holes were prepared and filled with MTA. They then divided into 3 main groups based on the chosen time intervals (15 min, 24 h, and 72 h). Main groups were divided into 3 subgroups based on the CDP [chlorhexidine gluconate (CHX), ozone, laser, and control]. RM-GIC was applied on MTA after CDP for all groups. A universal testing device was then used for test and the data was statistically analysed. CHX showed significantly lower SBS values except ozone and laser than the control (p < 0.05). There were no statistically significant differences among the time intervals. As a result, CHX decreased the bond strength between the MTA and RM-GIC while ozone and laser had no negative effect.

Evaluation of the shear bond strength of zirconia to a self-adhesive resin cement after different surface treatment

OBJECTIVES

The aim of this study was to evaluate the SBS of pre-sintered and sintered zirconia to a selfadhesive resin cement after various treatment (air abrasion and the Nd:YAG laser irradiation at varying power levels -1 W, 2 W and 3 W).

MATERIAL AND METHODS

Ninety-nine zirconia specimens were prepared and divided into 3 groups: control (with no surface treatment); and pre-sintered and sintered groups with surface treatment. Surface treatment was applied before sintering in the pre-sintered group and after sintering in the sintered group. After following all protocols, a resin cement was layered on the zirconia surface. Shear bond strength was measured using a universal testing machine. The results were subjected to the statistical analysis. The surface topography and phase transformation of zirconia were evaluated using the atomic force microscopy (AFM), scanning electron microscopy (SEM) and X-ray diffraction (XRD) analyses after surface treatment.

RESULTS

The laser irradiation (3 W, 1 W and 2 W) of the pre-sintered zirconia surface resulted in the highest SBS values (p < 0.001), while the lowest SBS values were obtained with airborne particle abrasion of the pre-sintered and sintered zirconia surfaces.

CONCLUSIONS

Laser irradiation increased the SBS of pre-sintered zirconia to a resin cement. Surface treatment with air abrasion had a lesser effect on the SBS values.

Antibacterial activity of silver nanoparticles activated by photodynamic therapy in infected root canals

BACKGROUND

Root canal disinfection includes mechanical, chemical and biological struggle against microorganisms (MOs). Photodynamic therapy (PDT) and nanoparticle (NP) agents may be proposed as an alternative for use against intracanal infections due to their ability to disrupt biofilm and prevent bacterial adhesion to dentin. The use of NP agents in combination with light/photosensitizer (PS) agents increases the efficiency of PDT in root canal disinfection.

OBJECTIVES

The aim of the study was to evaluate the effect of light application - PDT - on the antibacterial activity of the combination of a PS agent (toluidine blue O -TBO) and an NP agent (silver nanoparticles - AgNPs) for the disinfection of the root canals inoculated with Enterococcus faecalis (E. faecalis).

MATERIAL AND METHODS

In this study, concentrations of 20 ppm of TBO and 10 ppm of AgNPs, which showed the highest antibacterial activity against E. faecalis in the TBO/AgNPs combination, were used according to the preliminary studies. After instrumentation, 120 human, single-rooted, straight-canal mandibular premolars of a standard length of 13 mm were contaminated with bacteria, and experimental procedures were conducted against 21-day-old mature biofilm. The teeth were randomly divided into 5 main experimental groups: TBO/light; AgNPs; TBO/AgNPs; AgNPs/light; and TBO/AgNPs/light. Then, these main groups were divided into 2 subgroups each, according to the 2 application time periods (30 s and 60 s) (n = 10). The remaining 20 teeth constituted positive and negative control groups. The data was analyzed with the Kolmogorov-Smirnov test, one-way analysis of variance (ANOVA), Tukey's honestly significant difference (HSD) test, and the Bonferroni correction.

RESULTS

The NaOCl group provided a bacterial reduction that was higher than in all other groups in a statistically significant manner. Light application on the TBO/AgNPs combination was the group that provided the highest bacterial reduction after NaOCl.

CONCLUSIONS

The photoactivation of the TBO/AgNPs combination led to an increase in the effect of PDT, and it has the potential to be used as an adjunct for disinfection of the root canal system.

Human pulp tissue dissolution ability of different extracts of Sapindus mukorossi: An in vitro study

Objective

Due to the many negative properties of sodium hypochlorite used in current root canal treatment, interest in biocompatible natural agents is increasing day by day. The aim of this study was to evaluate whether various extract solutions of Sapindus mukorossi have dissolution effects on human pulp tissues.

Methods

Primarily powder extracts were obtained by extracting fruit shells of S. mukorossi in different solvents (ethanol, methanol, buthanol and distilled water). The test solutions were prepared and randomly separated into six groups with 10 samples in each group: ethanol extract, methanol extract, butanol extract, distilled water extract of S. mukorossi, sodium hypochlorite (NaOCl) and the control group. Among these, S. mukorossi extracts were separated into two subgroups, depending on their concentration level (50 µg/mL and 100 µg/mL). The pulp tissues of freshly extracted human molars were used for dissolution test. The weights of the pulpal tissues were measured and recorded for two times after the samples were placed in the solutions. Statistical analysis for all descriptive statistics was performed using SPSS 22 (P < 0.05).

Results

Our results showed that maximum percent yield of preparation was obtained in methanol extract of S. mukorossi. Among all of the groups, the best dissolution capacity was seen in the NaOCl group (positive control group). Among S. mukorossi groups, the best tissue solvent solution was found in SMM group at 50 µg/mL and SMB group at 100 µg/mL.

Conclusion

The different extracts of S. mukorossi had a capacity to dissolve pulp tissue but this capacity was less than NaOCl. Therefore, further studies will enable the creation of a commercial solution for clinical use by increasing the effectiveness of S. mukorossi while combining it with other endodontic irrigation solutions.

Effect of Mouthrinse Containing Propolis on Oral Microorganisms and Human Gingival Fibroblasts

Objectives: The aim of this study was to compare the effects of four different mouthrinse containing propolis solutions and mouthrinse containing 0.2% chlorhexidine (CHX) on oral microorganisms and human gingival fibroblasts.

Methods: Four different solutions of propolis were prepared and propylene glycol and alcohol were used as solvents for each propolis sample. Mouthrinse containing propolis was prepared at four different concentrations as 10%, 5%, 2.5% and 1%. Besides, CHX was used as control group. The antibacterial effects of five solutions on oral microorganisms were tested and their cytotoxic effects on human gingival fibroblasts were evaluated by agar diffusion test.

Results: At this concentrations effectiveness of mouthrinse containing propolis samples on oral microorganisms were not found as effective as CHX. On the contrary, samples found less cytotoxic on human gingival fibroblasts than CHX.

Conclusions: Standardized preparations of propolis can be used as a mouthrinse at appropriate concentrations. To obtain a standardized chemical composition, advanced researches are needed. (Eur J Dent 2007;1:195-201)

Association of Toll-like receptors 2, 3, and 4 genes polymorphisms with periapical pathosis risk

Background

The aim of this study was to investigate the role of gene variations of Toll-like receptors (TLR) 2, 3, and 4 on genetic susceptibility to periapical pathosis.

Material and Methods

One hundred patients were included in the study and divided into two groups as follows; Control Group (n=50) that have root canal treatment and no periapical lesion, Patient Group (n=50) that have root canal treatment and periapical lesion. TLR2 Arg753Gln, TLR3 (c.1377C/T) and TLR4 Asp299Gly and Thr399Ile polymorphisms were genotyped by using PCR-RFLP. Genotypical analysis of control and patient groups were investigated to disclose whether there is any association between periapical lesions and gene variations.

Results

There are no significant statistical differences between control and patient groups according to TLR 2 and 4 gene sequence. On the contrary, CC allele detected 74% for TLR 3 in patient group, and this difference was found to be statistically significant (p < 0.005).

Conclusions

According to these results, it can be suggested that patients with Toll-like receptor 3 gene polymorphisms could be susceptible to periapical pathosis.

Key words:Toll-like receptors, periapical pathosis, endodontics.

Comparison of various current electronic apex locators to determine the working length using the clearing technique

BACKGROUND

Correct working length determination is an important step for successful endodontic therapy.

OBJECTIVE

The objective was to compare in vitro the accuracy of three electronic apex locators (EALs) (DentaPort ZX [Morita Co., Tokyo, Japan], SIROEndo Pocket [Sirona Dental Systems, NY, USA], and Rootor [Meta Biomed, Cheongwon-gun, Korea]) in detecting the major foramen using the clearing technique.

MATERIALS AND METHODS

Forty-five human extracted single-rooted teeth with mature apices were used for the study and divided into three groups of 15 teeth each. All teeth were embedded in an alginate model, and the electronic measurements were taken following the manufacturers' orientations. Then, the teeth were cleared and photographed under a stereomicroscope with a digital camera. The distance from the file tip to the major foramen was measured using image analysis software program. Statistical analysis was performed using the Kruskal-Wallis, Mann-Whitney U, and Chi-square tests at a significance level of 0.05.

RESULTS

The mean distances from the file tip to the major foramen were 0.164 ± 0.292, -0.162 ± 0.234, 0.341 ± 0.166 mm in the DentaPort ZX, SIROEndo Pocket, and Rootor groups, respectively. Statistical analysis showed that there was a significant difference between SIROEndo Pocket and Rootor (P < 0.05). However, no significant difference was found between DentaPort ZX and other EALs (P > 0.05).

CONCLUSION

DentaPort ZX located the major foramen with 100% accuracy within the range of ± 0.5 mm. However, the accuracy of the SIROEndo Pocket and Rootor in locating the major foramen within ± 0.5 mm was 73.3% and 86.7%, respectively. All EALs showed an acceptable determination of the major foramen within the range of ± 0.5 mm.

In vitro comparison of four different electronic apex locators to determine the major foramen using the clearing technique

OBJECTIVES

The aim of this study was to evaluate the accuracy of four electronic apex locators (EALs) (DentaPort ZX, Raypex 5, Endo Master and VDW Gold) in detecting the major foramen using the clearing technique.

MATERIALS AND METHODS

Forty-eight extracted single-rooted extracted teeth with mature apices were used for the study and divided into four groups of 12 teeth each. All teeth were embedded in an alginate model. Electronic measurements were taken using a size 15 K-file attached to the holder. Then, the teeth were cleared and photographed under a stereomicroscope with a digital camera. The distance between the tip of the file and the major foramen was measured by using an image analysis software program. Positive and negative values were recorded when the file tip was beyond or short of the major foramen and zero value when the file tip and the major foramen coincided. Statistical analysis was performed using the Kruskal-Wallis and Chi-square tests at a significance level of 0.05.

RESULTS

Mean distance from the file tip to the major foramen were 0.302 ± 0.202, 0.065 ± 0.293, 0.117 ± 0.475, and 0.258 ± 0.160 mm in the DentaPort ZX, Raype 5, Endo Master, and VDW Gold groups, respectively. There were no statistically significant differences among the devices (P > 0.05) .

CONCLUSION

Under the experimental conditions, all EALs showed an acceptable determination of the major foramen.

Electrophysiological evidence on epileptiform activity enhanced by electrical stimulation of teeth in rats

The aim of this study was to evaluate the possible effects of electrical stimulation (ES) of tooth on penicillin-induced epileptiform activity in rats. Experiment was realized on 24 adult male Sprague Dawley rats. Rats were assigned three groups [stimulation group (SG), penicillin group (PG), and penicillin+stimulation group (PSG)]. In SG, ES was only applied. Ten pulses of electrical current were delivered to the teeth for a duration of 2 milliseconds at 1-second intervals from a stimulator. Currents were applied in the range of 40-240 μA with 40 μA steps. Electrocorticography (ECoG) recordings were taken before and after ES. In PG, ECoG recordings were taken before and during the injection of penicillin. In PSG, after epileptiform activity was induced, ES was applied and ECoG recordings were taken as in SG. All the data were analyzed with Student's t test. Applied currents did not cause any epileptiform activity in SG. When the PSG was compared with the PG it was seen that the spike frequency of epileptiform activity increased in a statistically significant way after application of 240 μA (P < 0·05). On the other hand current application caused an increase in the spike amplitude of the PSG compared with the amplitude of the PG, but it was not statistically significant. We concluded that ES of tooth with high current can trigger epileptiform activity in rats. For this reason, further research is required to evaluate the effects of ES of tooth for pulp testing on epileptic human subjects and antiepileptic drug users.

Bond strength of calcium silicate-based sealers to dentine dried with different techniques

OBJECTIVE

To assess the influence of various canal-drying techniques on the push-out bond strength between radicular dentine and both MTA Fillapex and iRoot SP sealers.

MATERIALS AND METHODS

Eighty extracted single-root teeth were instrumented with ProTaper Universal rotary instruments to a size F4. The teeth were randomly assigned to 1 of 4 groups as follows: group 1, excess fluid in the canals was removed using a Luer vacuum adapter; group 2, the canals were dried with a single paper point; group 3, the canals were dried with 3-5 paper points, and group 4, the canals were rinsed with 95% ethanol and then dried with 3-5 paper points. In each group, the specimens were subgrouped according to root canal sealer into either subgroup A (MTA Fillapex) or subgroup B (iRoot SP sealer). Horizontal sections (thickness 1 ± 0.1 mm) were obtained from each specimen and a push-out test was performed using a universal testing machine at a crosshead speed of 1 mm/min on root slices. Statistical analysis was done using the Kruskal-Wallis test and Dunn's test for pair-wise comparisons. p < 0.05 was considered statistically significant.

RESULTS

Canals dried with only 1 paper point and obturated with the iRoot SP sealer (subgroup 2B) showed significantly higher bond strengths to the root canal wall compared to all other subgroups (p < 0.05), except for subgroup 1B (p > 0.05).

CONCLUSIONS

The canal-drying technique influenced the adhesive bond strength between calcium silicate-based root canal sealers and the root canal wall.

Comparison of influence of different manufacturing methods on the cleaning efficiency of rotary nickel-titanium files

The purpose of this study was to evaluate and compare cleaning effectiveness of TwistedFile, GT series X, Revo-S, RaCe, Mtwo, and ProTaper Universal rotary files in curved canals. Seventy mesiobuccal canals of extracted human first maxillary molars were divided into seven groups of 10 samples each. Canals were prepared with six nickel-titanium (NiTi) rotary systems and manual K-Flexofile. Irrigation was performed with 2 mL 2.5% NaOCl solution after each file, and 5 mL 2.5% NaOCl was used for the final flush. After the roots were split longitudinally, the presence of debris and smear layer was visualized using scanning electron microscopic photomicrographs taken at coronal, middle, and apical third. Mean scores for debris and the smear layer were calculated and statistically analyzed for significance between groups using the Kruskal-Wallis nonparametric analysis of variance (P < 0.05) and Mann-Whitney U test (P < 0.001). There was no significant difference among the groups in terms of debris and smear layer scores (P > 0.05). Without considering the preparation method used, while no statistically significant difference was found between the coronal third and the middle third (P > 0.05), higher amount of debris and smear layer were found in apical third (P = 0.001). The new generation of NiTi rotary files including the Twisted File and GT Series X presented similar cleaning effectiveness compared with traditionally ground NiTi rotary files.

Antibacterial activity and physical properties of conventional glass-ionomer cements containing chlorhexidine diacetate/cetrimide mixtures

STATEMENT OF THE PROBLEM

Hand excavation instruments are not as efficient as that with rotary burs in atraumatic restorative treatment (ART).

PURPOSE

To evaluate the antibacterial activity (ABA), microhardness numbers (VHN), and cumulative fluoride releasing (CFR) patterns of conventional GICs (Fuji IX (FX) and Ketac Molar (KM)) containing chlorhexidine diacetate/cetrimide mixtures (2.5%/2.5%) (AB).

MATERIALS AND METHODS

The powders of ABs were added to powders of FX and KM selected as experimental groups (EXPs). FX and KM were assigned as controls (CNTs). ABA against S.mutans (MS) and L.casei (LB) were examined between 1-90 days. VHN were calculated after 24 hours and CFR patterns measured between 1-30 days. Analysis of variance was used for comparison (p<0.05)

RESULTS

Differences were found between EXPs regarding MS levels at days 1, 7 and 60 as well as for LB at all time periods (p<0.05). VHN decreased in EXPs compared to CNTs (p<0.05), and no differences were found between EXPs (p>0.05). CFR patterns tended to decrease in EXPs compared to the CNTs, but no differences were found between EXPs (p>0.05) CLINICAL SIGNIFICANCE These mixtures could be recommended for ART procedures to provide beneficial antibacterial effects without seriously deteriorating the physical properties of selected GICs.

Comparison of the sealing ability of three filling techniques in canals shaped with two different rotary systems: a bacterial leakage study

OBJECTIVE

This study compared the sealing ability of 3 current filling techniques in root canals shaped with 2 different rotary systems.

STUDY DESIGN

Eighty human extracted mandibular premolars were divided randomly into 2 similar groups of 40 each and instrumented with either ProTaper (Dentsply Maillefer, Tulsa, OK; group A) or Mtwo (VDW; Antaeos, Munich, Germany; group B) rotary systems. Each group was divided into 3 subgroups (n = 10) and 2 control groups (n = 5). Canals were filled either with the tapered single-cone technique (SC; subgroups A1 and B1), with lateral condensation (LC; subgroups A2 and B2), or warm vertical compaction (WVC; subgroups A3 and B3). AH Plus was used as a root canal sealer in all groups. Samples were sterilized in an ethylene oxide sterilizer for 12 hours. The apical 3-4 mm of the roots were immersed in brain-heart infusion culture medium with phenol red indicator within culture chambers. The coronal access of each specimen was inoculated every 48 hours with a suspension of Enterococcus faecalis. Bacterial leakage was monitored every 24 hours for 8 weeks. The data obtained were analyzed using a chi-squared test, and P was set at .05.

RESULTS

In group A, 70% of the specimens filled with SC (subgroup A1), 50% of the specimens filled with LC (subgroup A2), and 20% of the specimens filled with WVC (subgroup A3) leaked. There was no statistically significant difference between the subgroups (P > .05). In group B, bacterial leakage was observed in 50% of SC samples (subgroup B1), 40% of LC samples (subgroup B2), and 50% of WVC samples (subgroup B3). There was no statistically significant difference between subgroups B1, B2, and B3 (P > .05). There was also no statistically significant difference between group A and group B (P > .05).

CONCLUSION

Filling with SC, LC, and WVC techniques in canals treated with ProTaper or Mtwo rotary instruments showed similar levels of sealing efficacy.

Treatment of horizontal root fractures using a triple antibiotic paste and mineral trioxide aggregate: a case report

This case report describes the treatment of a horizontal root fracture in a maxillary central incisor (tooth #8) using a triple antibiotic paste and mineral trioxide aggregate. A nonsurgical endodontic treatment was performed to a coronal root canal fragment of tooth #8. During the treatment procedure, 1% sodium hypochlorite solution was used for irrigation and a triple antibiotic paste was used as an intracanal medicament. The coronal part of the canal was obturated with mineral trioxide aggregate totally. At follow-up examination after 12 months, the tooth was asymptomatic and radiographically showed repair of the fracture region. Healing was achieved without any need for further interventions.

Antibacterial Activity and Physical Properties of Glass-ionomer Cements Containing Antibiotics

The incorporation of low quantity antibiotics into glass-ionomer cement can be effective for use with the ART approach.

Influence of storage media containing Salvia officinalis on survival of periodontal ligament cells

AIM

The purpose of this study was to determine the ability of Salvia officinalis (S. officinalis) extracts to serve as a storage medium for the maintenance of periodontal ligament (PDL) cell viability of avulsed teeth.

METHODS AND MATERIALS

PDL cells were obtained from healthy third molars and cultured in Dulbecco's Modi?ed Eagle's Medium (DMEM). Cultures were subjected to 4, 2.5, 1.5, and 0.5% S. officinalis solutions, Hank's balanced salt solution (HBSS), phosphate buffered saline (PBS), and tap water. Tissue culture plates were incubated with experimental media at 37 masculineC for 1, 3, 6, 12 or 24 hours. PDL cell viability was assessed by trypan blue exclusion. Statistical analysis of the data was performed by one-way analysis of variance (ANOVA) complemented by the Tukey's test. The level of significance was 5% (p< 0.05).

RESULTS

The results showed 2.5% S. officinalis was a more effective storage medium than the other experimental solutions (p<0.05). Only at 1 hour and 3 hours was there found similar effect between 2.5% S. officinalis and HBSS. At 24 hours, 2.5% S. officinalis was found to be significantly better than the other solutions tested.

CONCLUSION

S. officinalis can be recommended as a suitable transport medium for avulsed teeth.

CLINICAL SIGNIFICANCE

The findings of this study support the use of S. officinalis as another option for clinicians to use to store and transport avulsed teeth until reimplantation procedures can be done.

Effect of mouthrinse containing propolis on oral microorganisms and human gingival fibroblasts

OBJECTIVES

The aim of this study was to compare the effects of four different mouthrinse containing propolis solutions and mouthrinse containing 0.2% chlorhexidine (CHX) on oral microorganisms and human gingival fibroblasts.

METHODS

Four different solutions of propolis were prepared and propylene glycol and alcohol were used as solvents for each propolis sample. Mouthrinse containing propolis was prepared at four different concentrations as 10%, 5%, 2.5% and 1%. Besides, CHX was used as control group. The antibacterial effects of five solutions on oral microorganisms were tested and their cytotoxic effects on human gingival fibroblasts were evaluated by agar diffusion test.

RESULTS

At this concentrations effectiveness of mouthrinse containing propolis samples on oral microorganisms were not found as effective as CHX. On the contrary, samples found less cytotoxic on human gingival fibroblasts than CHX.

CONCLUSIONS

Standardized preparations of propolis can be used as a mouthrinse at appropriate concentrations. To obtain a standardized chemical composition, advanced researches are needed.

Fracture resistance of the buccal cusps of root filled maxillary premolar teeth restored with various techniques

AIM

To compare the cusp fracture resistance of teeth restored with composite resins and two post systems.

METHODOLOGY

Eighty extracted single-rooted human maxillary premolars were randomly assigned to eight groups (n = 10). Group 1 (control) did not receive any preparation. From groups 2 to 8, the teeth were root filled and mesio-occluso-distal (MOD) cavities were prepared. Group 2 remained unrestored. Group 3 was restored with packable resin composite using a single-step adhesive. Group 4 was restored with packable resin composite using a single-step adhesive and a thin layer of flowable resin composite. Group 5 was restored with packable resin composite using a total-etch two-step adhesive. Group 6 was restored with ormocer resin composite using a total-etch two-step adhesive. Group 7 was restored with an endodontic glass fibre post and hybrid resin composite using a total-etch two-step adhesive. Group 8 was restored with an endodontic zirconium post and hybrid resin composite using a total-etch two-step adhesive. The teeth were then mounted in a universal testing machine, the buccal cusp loaded (30 degrees ) until fracture, and the data analysed statistically.

RESULTS

Group 1 had the greatest fracture resistance, and group 2 the poorest. Groups 5-8 had significantly greater (P < 0.05) fracture resistance than groups 3 and 4. No significant differences were found between groups 3 and 4, or amongst groups 5-8 (P > 0.05).

CONCLUSIONS

For root filled maxillary premolars with MOD cavities, adhesive resin composite restorations, with and without glass and zirconium posts, increased the fracture resistance of the buccal cuSPS. A total-etch two-step adhesive increased significantly fracture resistance more than a one-step adhesive. For the one-step adhesive, an additional layer of flowable resin composite did not enhance fracture resistance.

Nonsurgical Endodontic Treatment of Dens Invaginatus in a Mandibular Premolar with Large Periradicular Lesion: A Case Report

This case report describes the treatment of a dens invaginatus in a mandibular premolar with large periradicular lesion. A nonsurgical endodontic treatment was performed to tooth #28. During the treatment procedure, calcium hydroxide and a triple antibiotic paste were separately used for intracanal dressing. The apical third of the canal was obturated with mineral trioxide aggregate (MTA), and the remaining canal space was obturated with gutta-percha and AH 26 root canal sealer, using a lateral condensation technique. At follow-up examination after 1 year, the tooth was asymptomatic and radiographically showed repair of the lesion. Healing was achieved without any need for further endodontic surgical intervention.

The lamp effect of laser Doppler flowmetry on teeth

The aim of this study is to analyse the intra and extracoronal scattering of laser light. Twelve vital teeth from 12 volunteer individuals (aged 22-29 years) were used. The camera removing the charge coupled device's infrared cut filter was used for imaging the laser Doppler flowmetry light during pulpal blood flow measurement. When the obtained photos were analysed, it was seen that the laser beam caused the tooth to shine like a lamp and it also illuminated the tissues inside the mouth (tongue, lips, adjacent teeth, etc.). As a result, it was shown that when the necessary cautions were not taken, the laser could scatter all around the tissues surrounding the tooth. Because of the conductive characteristic of the fibre and the optical characteristics of the tooth, we think that the beam is inevitably scattered onto the tissues outside the pulp and together with the isolation of the gingiva, crown should be isolated, as well.

Penetration depth of laser Doppler flowmetry beam in teeth

OBJECTIVE

The aim of this study was to determine the penetration depth of laser light in teeth for contact and noncontact probe tip.

STUDY DESIGN

Fifty-one freshly extracted human mature maxillary and mandibular single rooted teeth were selected for the study. A laser Doppler flowmeter was used as a laser source. A digital camera was used to take pictures (with "night shot" mode in total darkness). When probe tip was in contact and when it was 1 mm away from the tooth, the depths of the areas illuminated in high and low density were measured.

RESULTS

In contact probe, root was illuminated to 4.28 +/- 0.14 mm depth with high density and 13.27 +/- 0.27 mm depth with low density. In noncontact probe, 4.36 +/- 0.16 mm with high density and 13.28 +/- 0.30 mm with low density of illumination were seen on the root. Between contact and noncontact probe situations the difference was not statistically significant in the depth of illumination. On the other hand, in both groups the difference between areas illuminated in high and low density was statistically significant (P < .05).

CONCLUSION

Contact or noncontact of the probe on tooth surface did not show any significant difference in light penetration. Besides, we think that, for the present, it is impossible to eliminate the contamination from periodontal tissues completely even if the necessary precautions (periodontal paste etc.) are taken.

Apical extrusion of intracanal bacteria following use of two engine-driven instrumentation techniques

AIM

To evaluate the number of bacteria extruded apically from extracted teeth ex vivo after canal instrumentation using the two engine-driven techniques utilizing nickel-titanium instruments (ProTaper and System GT).

METHODOLOGY

Forty extracted single-rooted human mandibular premolar teeth were used. Access cavities were prepared and root canals were then contaminated with a suspension of Enterococcus faecalis and dried. The contaminated roots were divided into two experimental groups of 15 teeth each and one control group of 10 teeth. Group 1, ProTaper group: the root canals were instrumented using ProTaper instruments. Group 2, System GT group: the root canals were instrumented using System GT instruments. Group 3, control group: no instrumentation was attempted. Bacteria extruded from the apical foramen during instrumentation were collected into vials. The microbiological samples from the vials were incubated in culture media for 24 h. Colonies of bacteria were counted and the results were given as number of colony-forming units. The data obtained were analysed using the Kruskal-Wallis one-way analysis of variance and Mann-Whitney U-tests, with alpha = 0.05 as the level for statistical significance.

RESULTS

There was no significant difference as to the number of extruded bacteria between the ProTaper and System GT engine-driven systems (P > 0.05).

CONCLUSIONS

Both engine-driven nickel-titanium systems extruded bacteria through the apical foramen.

Endodontic Treatment of a Large Cyst-Like Periradicular Lesion Using a Combination of Antibiotic Drugs: A Case Report

This case report describes the endodontic treatment of a large cyst-like periradicular lesion using a combination of antibiotic drugs. A 15-yr-old boy with a large cyst-like lesion from the apices of his teeth 29 to 31. Conservative root canal treatment was performed (tooth #30). During treatment procedure, 2.5% sodium hypochlorite solution was used for irrigation and a combination of antibiotic drugs was used for the intracanal dressing. Periapical healing was observed 3-month after initial treatment and continued at the 7-month review.

Effect of gingiva on laser doppler pulpal blood flow measurements

The purpose of this study was to evaluate the effect of labial and palatinal gingiva on laser Doppler pulpal blood flow measurements. Twenty upper central incisor teeth determined to be vital from 20 volunteers were included into the study. To stabilize the probe, a laboratory-made acrylic splint positioned the probe labially on the cervical third of the tooth crown. We collected measurements without any gingival covering, and under three conditions: after application of an opaque paste on the labial gingiva, the palatal gingiva, or both the labial and palatal gingiva. The measurement values decreased 46% when there was opaque paste on labial gingiva, 10% on palatinal gingiva, and 63% on both. The decrease in the values when there was an opaque paste on palatinal gingiva was not statistically significant (p > 0.05). The differences between all other groups were statistically significant (p < 0.05). In these measurements, the contribution of labial gingiva to laser Doppler pulpal blood flow measurements is more than that of palatinal gingiva.

The sources of laser Doppler blood-flow signals recorded from vital and root canal treated teeth

OBJECTIVES

The aim was to determine the strength of signals derived from the dental pulp and those from the surrounding tissues in human teeth using the laser Doppler flowmetry (LDF).

METHODS

Twenty-six vital teeth (13 experimental and 13 controls) from 12 patients were used. Experimental teeth had root canal treatment in a single visit and their healthy antimeres were controls. Blood flow measurements were made before and after local anaesthesia, after root canal preparation, following root canal filling and coronal restoration.

RESULTS

Perfusion unit (PU) values recorded from empty pulp chamber were determined to be only 30% lower than the values recorded before anaesthesia from the experimental intact teeth. When the measurements in the group were compared with each other the values of variation in the both groups were not statistically significant. The variation between the groups when the measurement values before anaesthesia, 10min after anaesthesia and after coronal restoration were compared, it was not statistically significant (P>0.05). The variation between the groups after preparation and root canal filling in their values of measurements was important statistically (P<0.05). The measurement values of the study group were lower than that of the control group.

CONCLUSIONS

In pulpal, LDF a major portion of the signal comes from tissues other than pulp. Without taking precautions (such as rubber-dam application) in pulp blood flow measurements, the results may be inconsistent.

In vitro fracture resistance of root-filled teeth using new-generation dentine bonding adhesives

AIM

To compare the fracture resistance of root-filled premolar teeth restored with new-generation dentine bonding adhesives.

METHODOLOGY

Sixty extracted single-rooted human maxillary premolar teeth were used. Access cavities were prepared, and the roots were instrumented with K-files to an apical size 50 using a step-back technique. Root fillings were accomplished using gutta percha (Sure-Endo, Seoul, Korea) and AH Plus root canal sealer (Dentsply DeTrey, Konstanz, Germany) using the lateral condensation technique. The teeth were then randomly divided into six groups of 10 teeth each. A mesiodistocclusal (MOD) cavity was prepared in the teeth to the level of the canal orifices so that the thickness of the buccal wall of the teeth measured 2 mm at the occlusal surface and 3 mm at the cemento-enamel junction. Preparations were restored using the following adhesive systems: Etch & Prime 3.0 (Degussa AG, Hanau, Germany), Clearfil SE Bond (Kuraray, Osaka, Japan), Prompt L-Pop (ESPE, Seefeld, Germany), Panavia F (Kuraray, Osaka, Japan), Optibond Plus (Kerr, Orange, CA, USA) and Admira Bond (Voco, Cuxhaven, Germany); all preparations except those of the Panavia F and Admira Bond groups were further restored with resin composites. The Panavia F group was restored with amalgam and the Admira Bond group with Ormocer (Voco, Cuxhaven, Germany). The teeth were mounted in a Universal Testing Machine (Hounsfield, Surrey, UK), and the buccal walls were subjected to a slowly increasing compressive force until fracture occurred. The force of fracture of the walls of each tooth was recorded and the results in the various groups were compared. Statistical analysis of the data was accomplished using one-way anova.

RESULTS

There was no significant difference in the fracture resistance of any of the test groups.

CONCLUSIONS

In this laboratory study, the type of dentine bonding agents had no influence in the fracture resistance of teeth.