Ivana Miletić

Detection of Tumor Necrosis Factor α in Normal and Inflamed Human Dental Pulps

Abstract Background The aim of this study was to determine concentrations of tumor necrosis factor-α (TNF-α) in normal, painful, and asymptomatic human dental pulps. Methods Pulps were obtained from three groups of teeth, including healthy teeth, asymptomatic teeth with caries and/or large restoration, and symptomatic teeth with clinical diagnosis of irreversible pulpitis. Pulpal tissues were collected, prepared, and analyzed for TNF-α concentration by ELISA technique. Results Nonparametric Kruskal-Wallis test revealed significant differences between TNF-α concentration in normal samples (64.01 ± 53.12 pg/g) and irreversible symptomatic pulpal tissue (1,962.99 ± 1,288.75 pg/g), between irreversible symptomatic and asymptomatic (1,120.09 ± 649.72 pg/g), and between normal and irreversible asymptomatic pulpal tissue ( p = 0.000). Conclusions TNF-α may be an objective marker for determining extent of pulpal inflammation associated with irreversible pulpitis.

Tumor Necrosis Factor-Alpha in Peripical Tissue Exudates of Teeth with Apical Periodontitis

Aim. The aim of this study was to determine tumor necrosis factor-alpha (TNF-α) levels in periapical exudates and to evaluate their relationship with radiological findings. Methodology. Periapical exudates were collected from root canals of 60 single-rooted teeth using absorbent paper points. TNF-α levels were determined by enzyme-linked immunosorbent assays. The samples were divided into three groups according to the periapical radiolucent area. Results. Nonparametric Kruskal-Wallis test revealed significant differences between TNF-α concentrations in control group (40, 57±28, 15 pg/mL) and group with larger radiolucent areas (2365, 79±582, 95 pg/mL), as well as between control and canals with small radiolucent areas (507, 66±278, 97) (P<.05). Conclusions. The levels of TNF-α increase significantly in teeth with periapical pathosis, from smaller to bigger lesions. This research and its results have shown that objective analysis of the TNF-α levels enables establishment of a relationship between different concentrations of TNF-α and different radiological changes.

In vitro genotoxicity of root canal sealers

AIM To evaluate the effect of leakage on differences in genotoxicity of root canal sealers ex vivo according to their main components using two different cytogenetic assays. METHODOLOGY Six materials of different composition (GuttaFlow, Epiphany, Diaket, IRM, SuperEBA and Hermetic) were tested on human peripheral blood lymphocytes using the comet assay and chromosomal aberration analysis. Prepared materials were eluted in physiological solution for 1 h, 1 day, 5 and 30 days. Thereafter cultures were treated with 8 microg, 4 microg and 2 microg of each sealer. Frequencies of chromatide and chromosome breaks and accentric fragments were determined. Comet assay was used to evaluate primary DNA damage by measuring tail length and tail intensity. Chi-square, Fishers PLSD (Protected Least Significant Difference) and Kruskall-Wallis non parametric tests were used for statistical analysis. RESULTS After 1-h elution only the highest dose of Diaket, Hermetic and SuperEBA significantly (P = 0.035, P = 0.048, P = 0.037 respectively) affected the measured cytogenetic parameters. The migration ability of DNA was more strongly affected than induction of chromosomal aberrations. After elutions longer than 24 h none of the tested sealers exhibited a genotoxic effect. CONCLUSION Under the conditions used in the study all sealers had acceptable biocompatibility in terms of genotoxicity.

Comparison of Er:YAG Laser and Surgical Drill for Osteotomy in Oral Surgery: An Experimental Study

PURPOSE High-energy lasers have been proposed as an alternative to the conventional surgical drill in oral and maxillofacial surgery. The aims of this study were to compare thermal changes of the bone surface, procedure time, and volume of the removed bone after drilling with an erbium (Er):yttrium-aluminum-garnet (YAG) laser versus a low-speed surgical drill. The bone sections were observed under light microscopy and examined histologically. MATERIAL AND METHODS Thirty bone blocks were prepared from porcine ribs. On each block 2 holes (tunnel preparations) were performed using a low-speed, 1.0-mm-wide, surgical pilot drill and an Er:YAG laser (pulse energy, 1,000 mJ; pulse duration, 300 μs; frequency, 20 Hz). The temperature induced by the preparation techniques was measured using an infrared camera. The removed bone volume was calculated by a modified mathematical algorithm. The time required for the preparation was measured with a digital stopwatch and a time-measurement instrument integrated within the computer program. The cortical and spongiose surfaces of the specimens were examined microscopically and histologically under a light microscope with a high-resolution camera. RESULTS The Er:YAG laser removed significantly more bone tissue than the drill (P < .01) in a significantly shorter time (P < .01). The temperature was statistically lower during the laser preparation (P < .01). Cavities prepared with the laser were regular with clear sharp edges and knifelike cuts. In the drill group, the preparations exhibited irregular edges full of bone fragments and fiberlike debris. Histologic examination of the laser sides showed a 30-μm-thick altered sublayer. The tissue in the drill group was covered with a smear layer without any alterations. CONCLUSIONS The Er:YAG laser produced preparations with regular and sharp edges, without bone fragments and debris, in a shorter time, and with less generated heat. Thermal alterations in the treated surface were minimal.

Salivary Levels of TNF-α and IL-6 in Patients with Denture Stomatitis Before and After Laser Phototherapy

OBJECTIVE The aim of this study was to monitor therapeutic response by determining the level of proinflammatory cytokines TNF-alpha and IL-6 in whole unstimulated saliva in patients with denture stomatitis (DS), before and after laser phototherapy (LPT). BACKGROUND DS is an inflammatory condition that occurs in subjects who wear dentures, and it is a common oral mucosal lesion. A potential noninvasive treatment for DS patients is LPT. MATERIALS AND METHODS A sample consisting of 40 consecutive subjects was selected on a voluntary basis from patients who presented for the diagnosis and treatment of DS at the Oral Medicine Unit of the Medical Faculty at the University of Rijeka. A clinical examination was performed according to the standard clinical criteria. Lesions described as palatal inflammation were diagnosed as Newton type II denture stomatitis. The patients were randomly assigned to either an experimental group (20 patients receiving real LPT) or a control group (20 patients receiving inactive/placebo laser treatment). In order to determine the salivary levels of TNF-alpha and IL-6, ELISA (Sigma Immunochemicals, St Louis, MO) was performed. RESULTS Following treatment with LPT for 4 wk, the levels of TNF-alpha and IL-6 decreased significantly (p < 0.001) and were significantly different from controls (p < 0.001). CONCLUSION The results of this study suggest that LPT may be an efficacious choice of therapy.

Active versus passive microleakage of Resilon/Epiphany and gutta-percha/AH Plus

The purpose of this in vitro study was to assess the active versus passive dye microleakage and apical sealing ability of laterally condensed gutta-percha/AH Plus versus Resilon/Epiphany. One hundred and twenty teeth were instrumented and divided into experimental, positive and negative control groups. In group 1, the teeth were obturated with gutta-percha/AH Plus and in group 2 the teeth were obturated with Resilon/Epiphany. The apical seal was evaluated with a passive and active dye penetration test. Absorbance of the extracted dye was determined with a spectrophotometer. Resilon/Epiphany showed less dye penetration in comparison with the gutta-percha/AH Plus group (P < 0.05). There were no statistically significant differences between the passive and active dye penetration tests (P > 0.05). In this in vitro study, canals obturated with Resilon/Epiphany showed less apical leakage than those obturated with gutta-percha/AH Plus, regardless of the type of dye penetration test used.

Ablative potential of the erbium-doped yttrium aluminium garnet laser and conventional handpieces: a comparative study.

OBJECTIVES To compare the ability of the Variable Square Pulse technology (VSP-technology)-based erbium-doped yttrium aluminium garnet (Er:YAG) laser working in maximum speed (MAX) mode (1000 mJ, 300 micros, 20 Hz) and the high-speed handpiece to ablate enamel, to compare the ability of for the VSP-technology-based Er:YAG laser working in MAX mode and the low-speed handpiece to ablate dentin, and to analyze in vitro effects of Er:YAG ablation of enamel and dentine surfaces using scanning electron microscopy (SEM). BACKGROUND DATA A VSP-technology-based Er:YAG laser operating in MAX mode should be appropriate for achieving the maximum ablating speed in hard dental tissues. MATERIALS AND METHODS The experiment was conducted on extracted, cleaned, sterilized human molar teeth. Cavity preparations were made in hard dental tissues using the VSP-technology Er:YAG laser in MAX mode, in enamel using the high-speed handpiece, and in dentin using the low-speed handpiece at different time intervals. A laser triangulation profilometer was used to determine cavity volumes. The cavity surfaces of five specimens were examined using SEM. RESULTS The Er:YAG laser removed a volume of enamel that was 3.3 times as large as that removed by the high-speed handpiece in the same period of time. In dentin, the Er:YAG laser removed 8 to 18 times as much volume as the steel bur in the same period of time. The Er:YAG ablation rate in dentin was faster than in enamel. SEM of laser prepared cavities showed a well-defined surface, free of the smear layer. CONCLUSIONS The VSP-technology-based Er:YAG laser, working in MAX mode, is more efficient than mechanical drills for enamel and dentin ablation.

Influence of Different Pulse Durations of Er:YAG Laser Based on Variable Square Pulse Technology on Microtensile Bond Strength of a Self-Etch Adhesive to Dentin

OBJECTIVE The aim of the study was to evaluate the microtensile bond strength of a composite resin to dentin modified with three different pulse durations of the Er:YAG laser based on variable square pulse technology and with one self-etch adhesive. MATERIALS AND METHODS The entire occlusal enamel was removed to obtain flat dentin surface for 48 human molar teeth. The teeth were randomly divided into four experimental groups (n=12 per group), according to the pretreatment of dentin: (1) control group; (2) super short pulse (SSP) (50 μsec); (3) medium short pulse (MSP) (100 μsec); and (4) short pulse (SP) (300 μsec) with Er:YAG laser. The energy of the laser used was 80 mJ with average power of 0.8 W. The microtensile bond strength was tested with a universal testing machine. Two specimens from each experimental group were subjected to scanning electron microscopic (SEM) examination, to observe the irradiated surface. RESULTS Dentin surface treated with SSP showed significantly lower microtensile bond strength values (24±9.8 MPa) in comparison with the control group and SP group (35.3±12.8 and 32.9±10.7 MPa, respectively), (p<0.05). The MSP and SP groups did not show any statistically significant difference in microtensile bond strength in comparsion with the control group (p>0.05). CONCLUSIONS The use of SP and MSP of the Er:YAG laser with one step self-etch adhesive does not impair or improve the microtensile bond strength in dentin, whereas SSP may not be suitable for dentin surface treatment prior to bonding procedures.

Evaluation of cytotoxic and genotoxic effects of two resin-based root-canal sealers and their components on human leucocytes in vitro

AIM To evaluate the in vitro genotoxicity and cytotoxicity of two resin-based root canal sealers and to determine the type of cell death they induce. METHODOLOGY The sealers tested were Epiphany and RealSeal. Each component of the material (Epiphany Primer, Epiphany Thinning Resin, Epiphany Sealant, RealSeal Primer, RealSeal Thinning Resin and RealSeal Root Canal Sealant), components in permutual combinations and all components mixed together were tested on human peripheral blood leucocytes using ethidium bromide/acridine orange viability staining and comet assay. Simultaneously, untreated negative control cultures were analysed in the same manner. DNA damage was evaluated following 4 h of treatment and after 24 h in the absence of the components of the materials. RESULTS After 4 h of treatment, except thinning resin, each individual component and the different combinations of components induced a significant increase in DNA migration ability (P < 0.05). After 24 h, combination of primer, thinning resin and sealant of both materials caused cell death inducing intense apoptosis. After 24 h, cells exposed to Epiphany Sealant and RealSeal Root Canal Sealant, both in polymerized and unpolymerized form, exhibited a level of DNA damage that was similar to the control. CONCLUSIONS Primer and thinning resin of both resin-based root canal sealers and their combinations were cytotoxic and induced apoptosis. Both sealants had no significant effect on the viability of the human leucocytes.

The Temperature Changes in the Pulp Chamber During Cavity Preparation with the Er:YAG Laser Using a Very Short Pulse

OBJECTIVE The aim of this study was to examine the temperature changes in the pulp chamber during cavity preparation with the Er:YAG laser (2940 nm) with a very short pulse (VSP). MATERIALS AND METHODS Nine groups of 10 intact molars each were used. One root of each sample was amputated and a thermocouple was inserted into the chamber. Class V cavity preparation in enamel was performed, and then preparation was performed in dentine. The enamel was lased with 400, 360, and 320 mJ in contact mode using a VSP with a duration of 100 microsec. The diameter of the fiber tip was 950 microm. Frequencies of 10, 12, and 15 Hz were used, and the total time of irradiation was 10 sec. The dentine was irradiated with 340, 280, and 200 mJ at 10, 8, and 5 Hz for 7 sec. Cooling was done with a water spray (73 psi and 50 mL/min). The differences were tested by MANOVA and the Bonferroni post hoc test. RESULTS The highest rise in temperature in the pulp was achieved after enamel irradiation with 400 mJ and 15 Hz (1.99 +/- 0.28 degrees C), and the lowest was after irradiation with 320 mJ and 10 Hz (0.70 +/- 0.18 degrees C). In dentine the highest temperature increase was achieved with 340 mJ and 10 Hz (1.37 +/- 0.42 degrees C), and the lowest was with 200 mJ and 5 Hz (0.43 +/- 0.18 degrees C). Two-way analysis of both enamel and dentine showed that the influence of energy on temperature increase was stronger than that of frequency. CONCLUSION Cavity preparation with an Er:YAG laser using VSP mode in vitro did not cause significant increases in temperature in the pulp chamber of human molars.