Citations
Citations
The use of flowable composite resins as liners in class II packable composite restoration has been suggested by some manufacturers. However, the contributions of this technique are unproven. The purpose of this study was to compare the gingival microleakage in class II packable composite restorations with or without the use of flowable composite resins as liners.
Slot cavities were prepared on both proximals of 80 extracted human molars and randomly assigned to 8 groups of 20 each. The gingival margins were located at 1mm above CEJ in 80 cavities (group1-4) and 1mm below CEJ in 80 cavities (group5-8). The prepared teeth were mounted in the customized tray with adjacent teeth to simulate clinical conditions and metallic matrix band (Sectional matrix) and wooden wedges were applied. After acid etching and application of Single Bond, each group was restored with the following materials using incremental placement technique: Group 1,5 (Filtek P60), group 2, 3, 4 and group 6, 7, 8 (AeliteFlo, TetricFlow, Revolution/Filtek P60). All specimens were thermocycled 500 times between 5℃ and 55℃ with 1 mimute dwell time, immersed 2% methylene blue dye for 24 hours and then rinsed with tab water. The specimens were embedded in clear resin and sectioned longitudinally through the center of restoration with a low speed diamond saw. Dye penetration at gingival margin was viewed at 20 magnification and analyzed on a scale of 0 to 4. Kruscal-Wallis One way analysis and Mann-Whitney Rank sum test were used to analyze the results.
The results of this study were as follows.
1. The leakage values seen at the enamel margin were significantly lower than those seen at the dentin margin(P<0.05).
2. On the enamel margin, packable composite resins with flowable liners showed lower leakage than those without flowable liners, but there were no significant differences among the four groups(P>0.05).
3. On the dentin margin, four groups demonstrated moderate to severe leakage, and there were no significant differences in leakage values(P>0.05).
Citations
The purpose of this study was to evaluate the resin infiltration into dentin of one-bottle adhesive systems and self-etching primer bonded to Class V cavities using confocal laser scanning microscope(CLSM).
Forty Class V cavities were prepared from freshly extracted caries-free human teeth. These teeth were divided into two groups based on the presence of cervical abrasion: Group I, cervical abrasion; Group II, wedge-shaped cavity preparation. Resin-dentin interfaces were produced with two one-bottle dentin bonding systems-ONE COAT BOND(OCB; Coltene®) and Syntac®Srint™(SS; VIVADENT)-, one self-etching priming system-CLEARFIL™ SE BOND(SB; KURARAY)- and one multi-step dentin bonding system-Scotchbond™Multi-Purpose(SBMP, 3M Dental Products)-as control according to manufacturers'instructions. Cavities were restored with Spectrum®(Dentsply). Specimens were immersed in saline for 24 hours and sectioned longitudinally with a low-speed diamond disc. The resin-dentin interfaces were microscopically observed using CLSM. The quality of resin-infiltrated dentin layers were evaluated by five dentists using 0-4 scale.
Confocal laser scanning microscopal investigations using primer labeled with rhodamine B showed that the penetration of the primer occurred along the cavity margins.
Statistical analysis using one-way ANOVA followed by Duncan's Multiple Range test revealed that the primer penetration of the group 2(wedge-shaped cavity preparation) was more effective than group 1(cervical abrasion) and that of the gingival interfaces was more effective than the occlusal interfaces. In the one-bottle dentin bonding systems, the resin penetration score of OCB was compatible to SBMP, but those of SS and self-etching priming system, SB were lower than SBMP.
The purpose of this study is to evaluate the two warm gutta-percha filling techniques by measuring the weight changes of resin blocks before and after canal filling in ribbon shaped canal. Simulated ribbon shaped root canals in 30 transparent resin blocks were instrumented to #40 using .06 taper Profile. 15 resin blocks were obturated with gutta-percha using cold lateral condensation. Warm lateral condensation using the Endotec II was then accomplished on the same 15 blocks. Another 15 resin blocks were obturated using the System B. All canals were obturated without sealer. The resin blocks were weighed after canal preparation and after each subsequent obturation, and then weight changes of the resin blocks were calculated.
The results were as follows.
1. Warm lateral condensation using Endotec II and continuous wave of condensation using System B produced a denser obturation of gutta-percha compared with conventional cold lateral condensation (p<0.01).
2. There was no significant difference between warm lateral condensation and continuous wave condensation.
In conclusion, the warm gutta-percha condensation techniques like warm lateral condensation and continuous wave condensation can be expected to bring favorable canal obturation results in ribbon shaped canals.
Citations
The purpose of the present study was to evaluate the direct and indirect composite restorations which had been placed for 1 year.
The composite restorations which had been placed between 1999. Mar and 1999, Dec was evaluated after 1 year. For direct restorations, Spectrum (Dentsply, USA) and Z100 (3M, USA) were used in the anterior teeth and Surefil (Dentsply, USA) were used. For class V restorations of anterior and posterior teeth, Spectrum was used. For indirect restorations, Targis/Vectris system (Vivadent/Ivoclar, Liechtenstein) was used. 2 examiners evaluated marginal quality, proximal contact, discoloration, presence of 2nd caries, loss of filling and hypersensitivity of restorations. The restorations was clinically evaluated by modified methods based on USPHS.
60 teeth were evaluated. 59 were clinically acceptable and 1 restoration which was placed in class v cavity in the posterior tooth was fallen out. In most cases, the restorations were clinically acceptable. For restorations which had been directly placed in the class II cavities, loose proximal contact was indicated as the main complaints.
Most of Anterior and posterior restorations which bad been directly or indirectly placed for 1 year were clinically acceptable. For posterior teeth, loose proximal contact was indicated as the main problem in the directly placed Class II restorations. Long term clinical study is needed.
Citations
Citations
The purposes of this study were to evaluate the microtensile bond strength of one-step adhesives according to various dentin surface treatments and to observe the interface between resin(Z-100™) and dentin under SEM.
In this study forty-five non-caries extracted human molars and three adhesive systems were used; All-Bond 2(AB), One-Up Bond F(OU), AQ-Bond(AQ).; In Group 1, 2, 3, AB was used and tooth surfaces were treated by smearing(S), ultrasonic cleansing(US), etching(E) respectively. In Group 4, 5, 6, One-Up Bond F was used and tooth surfaces were also treated as the same way above. In Groups 7, 8, 9, AQ Bond was used and tooth surfaces were treated as the same way. Each specimen was prepared for microtensile bond testing, and were stored for 24hrs in 37℃ distilled water. After that, microtensile bond strength for each specimen was measured. Specimens were fabricated to examine the failure patterns of interface between resin and dentin and observed under the SEM.
The results were as follows;
1. The results(mean±SD) of microtensile test were group 1, 25.69±4.31MPa; group 2, 40.93±10.94MPa; group 3, 47.65±8.85MPa; group 4, 36.98±9.14MPa; group 5, 39.66±8.45MPa; group 6, 43.26±13.01MPa; group 7, 25.07±4.2MPa; group 8, 30.4±4.74MPa; group 9, 33.61±7.88MPa.
2. One-Up Bond F was showed the highest value of 36.98±9.14MPa in dentin surface treatment with smearing, and there were significant differences to the other groups(p<0.05).
3. All-Bond 2 was showed the highest value of 40.93±10.94MPa in dentin surface treatment with ultrasonic cleansing, but was no significant difference to One-Up Bond F(p>0.05).
4. All-Bond 2 was showed the highest value of 47.65±8.85MPa in dentin surface treatment with etching(10%phosphoric acid), and there were significant differences to the other groups(p<0.05).
5. All-Bond 2 was showed the highest value of 47.65±8.85MPa in dentin surface treatment according to manufacture's directions, but was no significant difference to One-Up Bond F(p>0.05).
6. AQ Bond was showed the lowest microtensile bond strength with various dentin surface treatment, and the were significant differences to the other groups(p<0.05).