microcirculation model

Introduction: An increase in the temperature of the pulp chamber occurs during polymerisation of all types of light-curing resin-containing restorative materials, due to both the exothermic reaction of the material and the energy absorbed during the curing process. Increase in temperature of the pulp chamber of primary teeth during the curing process or the thermal conductivity properties of coloured compomers (CCs) have not yet been investigated in detail. The aim of the present study was to investigate the increase in pulpal temperature in primary teeth during curing of CCs.Materials and Methods: A Class-II cavity was prepared on the extracted primary mandibular second molar. Pulpal microcirculation of the tooth was performed using an experimental mechanism. The study included 15 groups and 10 experiments in each. Seven different CCs: pink, blue, gold, silver, orange, lemon, green, respectively from two different manufacturers (Groups 1-7: Twinky Star; VOCO, Cuxhaven, Germany. Groups 8-14: Nova Rainbow; IMICRYL, Konya, Turkey.) and a tooth-CC (Group 15: Dyract XP; DENTSPLY, Weybridge, UK.) were applied in prepared cavity. In all groups the compomers were light cured for 40 s. Intrapulpal temperature changes (Delta t) in 20th and 40th second were recorded. In Group-15 the Delta t values in 10th second were also recorded as per the manufacturer's instructions. The Kruskal-Wallis test and the Mann-Whitney-U test were used for statistical analyses.Results: At the end of 40-s irradiation time, the orange, lemon and green colours of Nova Rainbow resulted in significantly lower Delta t values than the same colours of Twinky Star (p = 0.0001), and silver, blue, lemon, green, orange, and pink CCs of Nova Rainbow and the blue and silver shades of Twinky Star demonstrated lower Delta t values than the reported critical temperature increase (5.5 degrees C).Conclusion: An increase in the irradiation time consequently led to an increase in the intrapulpal temperature. Therefore, manufacturers should focus on production of new CCs with shorter polimerization time.C1 [Ertugrul, Ceylan Cagil] Pamukkale Univ, Dept Pediat Dent, Denizli, Turkey.[Ertugrul, Ihsan Furkan] Pamukkale Univ, Dept Endodont, Denizli, Turkey

microscopy evaluation

The aim was to investigate the cyclic fatigue life of two novel rotary compactors produced for MTA compaction and produced for gutta-percha compaction. Two-type of nickel-titanium rotary compactors were used (n = 20). A static model was preferred for this study due to simulating the clinical application of compaction and to obtain a baseline repository data of this type of instruments. OrthoMTA Compacter (25/0.02) and Revo Condensor (30/0.04) instruments were operated speed of 250 and 4,800 rpm, respectively at 35 degrees C until fracture occurred. The time to fracture was recorded, and the length of the fractured fragments was registered. The independent t-test was performed (p < .05). The fractured instruments were evaluated with a high-resolution field emission scanning electron microscope to allow visualization of the surfaces under several magnifications (x100 and x10,000). OrthoMTA Compacter (3679.27 NCF), was extremely different in the mean number of cycles to failure when compared with Revo Condensor (1269.48 NCF) (p < .0001). The mean length of the fractured tip of OrthoMTA Compacter and Revo Condensor were 4.87 mm and 4.51, respectively (p < .0001). The surfaces of the instruments shown typical features of cyclic fatigue failure, involving crack origins, fatigue regions, and an overload region. This is the first study in the literature to date evaluating the cyclic fatigue life of Revo Condensor and OrthoMTA Compacter. OrthoMTA Compacter presented higher cyclic fatigue life compared with Revo Condensor.C1 [Orhan, Ekim O.] Eskisehir Osmangazi Univ, Fac Dent, Dept Endodont, TR-26480 Eskisehir, Turkey.[Ertugrul, Ihsan F.] Pamukkale Univ, Fac Dent, Dept Endodont, Denizli, Turkey

temperature assessed with pulpal blood microcirculation model

Objective The aim of the study was to evaluate the effect of different dry-polishing regimens on the intrapulpal temperature assessed using a pulpal blood microcirculation model. Materials and Methods Eighty extracted human mandibular premolar teeth were used. Standardized class V cavity preparations were performed and were then restored. Teeth were divided into four main groups (n = 20): Fine polishing disc (SSF; 3M Sof-Lex, 3M ESPE, Minnesota); Super-fine polishing disc (SSS; 3M Sof-Lex); Spiral finishing wheel (SSW; 3M Sof-Lex); Enhance PoGo-One step diamond micro-polisher cup (EPO; Dentsply Sirona, Inc, Delaware). The main groups were divided: the low-load pressure (0.4N) and the high-load pressure (0.8N). The average change in intrachamber temperatures (Delta t), from initial to highest, were measured. Results The highest temperature increase was recorded in SSF08 (9.55 degrees C). The lowest value was recorded in EPO04 (1.9 degrees C). SSS08, SSW08, and EPO08 demonstrated significantly higher Delta t values than the low-load mode in SSS04, SSW04, and EPO04, respectively (P < .0001). Conclusions Temperature was the least affected by the diamond cup in both pressure modes, and it was also less affected by the spiral finishing wheel in the low-load mode than in the high-load mode. Fine and super-fine discs had the greatest effect on intrachamber temperatures. Clinical Significance The present study suggests intrachamber temperature can rise among different dry-polishing regimes. Dental practitioners should pay attention to dry-polishing regimens and pressures for reducing heat-related dental problems.C1 [Ertugrul, Ihsan Furkan] Pamukkale Univ, Dept Endodont, Fac Dent, Denizli, Turkey.[Orhan, Ekim Onur] Eskisehir Osmangazi Univ, Dept Endodont, Fac Dent, Eskisehir, Turkey.[Yazkan, Basak] Pamukkale Univ, Dept Restorat Dent, Fac Dent, Denizli, Turkey

The effect of micro-electric current and other activation techniques on dissolution abilities of sodium hypochlorite in bovine tissues

BACKGROUND: The aim of the study was to evaluate the effects of micro-electric current on sodium hypochlorite’s (NaOCl’s) tissue-dissolution abilities, compared with other activation methods, including sonic, ultrasonic, pipetting, and temperature. METHODS: Bovine muscle tissues (n = 154) with standard sizes and weights were prepared and divided into two temperature groups: room temperature and 45 °C. Each temperature group was divided into seven sub-groups by activation methods: D = distilled water (−control); NaOCl = 5.25 % passive NaOCl (+ control); P = 5.25 % NaOCl with pipetting; SA = 5.25 % NaOCl with sonic activation; UA = 5.25 % NaOCl with ultrasonic activation; E-NaOCl = 5.25 % NaOCl with micro-electric current; and E-NaOCl + P = 5.25 % NaOCl with micro-electric current and pipetting. Specimens were weighed before and after treatment. Average, standard deviation, minimum, maximum, and median were calculated for each group. Resulting data were analyzed statistically using multi-way ANOVA and Tukey HSD tests. The level of the alpha-type error was set at < 0.05. RESULTS: At room temperature, the E-NaOCl + P group dissolved the highest amount of tissue (p < 0.05), and the UA, SA, and P groups dissolved significantly higher amounts of tissue than did the positive control or E-NaOCl groups (p < 0.05). At 45 °C, there was no significant difference between the SA and E-NaOCl groups (p > 0.05), and the E-NaOCl + P group dissolved a higher amount of tissue than any other group (p < 0.05). CONCLUSIONS: Using NaOCl with micro-electric current can improve the tissue-dissolving ability of the solution. In addition, this method can be combined with additional techniques, such as heating and/or pipetting, to achieve a synergistic effect of NaOCl on tissue dissolution