Multidisciplinary approach to a subgingivally fractured incisor tooth: A case report.

This case report describes a multidisciplinary approach using orthodontic forced eruption to facilitate prosthetic restoration of a subgingivally fractured maxillary permanent central incisor. A 14-year-old male patient presented at the pediatric dental clinic due to unesthetic appareance and for management of a fractured maxillary right central incisor tooth. Intraoral examination revealed that the maxillary right central incisor had sustained a crown-root fracture with pulp exposure. We treated the tooth endodontically and performed orthodontic root extrusion with a modified Hawley appliance prior to prosthetic rehabilitation. Approximately 2-3 mm of extrusion of the tooth was obtained within 8 weeks. A fiber post was then inserted into the root canal, and final restoration was completed with an all-ceramic crown. Follow-up 18 months after treatment revealed good periodontal health, esthetics and normal function.

Resonance frequency analysis of 208 Straumann dental implants during the healing period.

The most important prerequisite for the success of an osseointegrated dental implant is achievement and maintenance of implant stability. The aim of the study was to measure the 208 Straumann dental implant stability quotient (ISQ) values during the osseointegration period and determine the factors that affect implant stability. A total of 164 of the implants inserted were standard surface, and 44 of them were SLActive surface. To determine implant stability as ISQ values, measurements were performed at the stage of implant placement and healing periods by the Osstell mentor. The ISQ value ranges showed a significant increase during the healing period. Except for the initial measurement, the posterior maxilla had the lowest ISQ values, and there was no significant difference among anterior mandible, posterior mandible, and anterior maxilla (P < .05). Implant length did not have a significant influence on ISQ value (P > .05). The second measurement was significantly higher in men compared with women (P < .05). The second measurement was significantly higher than the others at 4.8 mm, and for the final measurement, there were no significant differences between 4.8 and 4.1 mm, which were higher than 3.3 mm (P < .05). When comparing sandblasted, large-grit, acid-etched (SLA) and SLActive surface implants, there were no significant differences for insertion measurements, but for second measurements, SLActive was significantly higher (P = 0), and for the final measurement, there was no significant difference. It appears that repeated ISQ measurements of a specific implant have some diagnostic benefit, and the factors that affect implant stability during the healing period are presented.

A technique for removal of a fractured implant abutment screw.

The aim of this technique report was to present a procedure for removal of a fractured implant abutment screw. Whatever the cause, when an abutment fracture has occurred, the fractured screw segment inside the implant must be removed. The methods used by the clinicians may include the use of an endo-explorer self-made screwdriver and the use of implant repair kit available for some implant systems. The advantage of the presented method is that it may be extended to other implant systems that do not have a special repair kit and also that the technique is simple and does not require special equipment.

A technique to facilitate the fabrication of provisional restorations for ITI solid abutments.

The aim of this technique report was to present a procedure for the fabrication of provisional restorations for ITI solid abutments using impression caps in the laboratory with a number of advantages over intraoral techniques. There may be no need for cementation, and elimination of cementation may assist tissue healing.

Effects of different acids and etching times on the bond strength of glass fiber-reinforced composite root canal posts to composite core material.

OBJECTIVE: To investigate the effects of different acids and etching times on the bond strength of glass fiber-reinforced composite (FRC) posts to composite core material. METHOD AND MATERIALS: Twenty-six FRC posts (FRC Postec Plus) were randomly divided into 13 groups (each n = 2). One group received no surface treatment (control). The posts in the other groups were acid etched with 35% phosphoric acid and 5% and 9.6% hydrofluoric acid gel for four different etching times (30, 60, 120, and 180 seconds). A cylindric polytetrafluoroethylene mold was placed around the treated posts and filled with dual-cure composite core material (MultiCore Flow). All samples were light cured for 60 seconds. After 24 hours of water storage, the specimens were sectioned perpendicularly to the bonded interface under water cooling to obtain 2-mm post-and-core specimens. Eight specimens were made from each group. Push-out tests were performed at a crosshead speed of 0.5 mm/min using a universal testing machine. Data were analyzed by one-way ANOVA followed by the Tukey honestly significant difference test (alpha = .05). RESULTS: The lowest bond strength was observed in the control group (12.51 megapascal [MPa]). No statistical significant difference was observed among group H5-120 (20.31 MPa), group H9-120 (20.55 MPa), or group P-180 (20.57 MPa) (P > .05). These groups demonstrated the highest bond strength values (P < .05). CONCLUSION: For the FRC posts, all acid-etching procedures tested showed significantly increased bond strength when compared with the control group. Acid-etching with 5% hydrofluoric acid and 9.6% hydrofluoric acid for 2 minutes and with 35% phosphoric acid for 3 minutes (groups H5-120, H9-120, and P-180, respectively) demonstrated the highest bond strength values between the FRC post and composite core material. Although the bond strength was increased by prolonged acid etching, the microstructure of the FRC posts might have been damaged.

Effects of Er:YAG laser treatments on surface roughness of base metal alloys.

We investigated the effects of different Er:YAG laser treatments on the surface roughness of base metal alloys. A total of 36 specimens were prepared of two base metal alloys (Wiron 99, Bellabond plus). The surfaces of the specimens were standardized by gradual wet grinding with 320-, 600-, 800- and 1,000-grit silicon carbide paper for 10 s each on a grinding machine at 300 rpm. Specimens of each alloy were randomly divided into six groups (n = 6) comprising a control group (group C), a group sandblasted with Al(2)O(3) powder at 60 psi for 10 s through a nozzle at a distance of 10 mm (group S), and four Er:YAG laser (Fotona AT) treatment groups. The laser treatment groups were as follows: 500 mJ, 10 Hz, 100 µs (group 500MSP); 500 mJ, 10 Hz, 300 µs (group 500SP); 400 mJ, 10 Hz, 100 µs (group 400MSP); and 400 mJ, 10 Hz, 300 µs (group 400SP). Surface roughness measurements (Ra) were performed using a profilometer. The data were analysed by two-way ANOVA, and mean values were compared using Tukey's HSD test (α = 0.05). According to the two-way ANOVA results, the base metal alloys and interaction between base metal alloy and surface treatment were not statistically significant different (p > 0.05), the surface treatments were significantly different (p < 0.0001). For the two base metal alloy groups, no significant differences were observed among the control, 400MSP, and 400SP groups (p = 0.912), and these groups demonstrated the lowest Ra values. The highest Ra value was observed in group S (p < 0.05). Er:YAG laser treatment at 400 and 500 mJ/10 Hz is not an alternative method for surface roughening of base metal alloys.

Effects of air-polishing powders on color stability of composite resins

OBJECTIVES: The purpose of this study was to investigate the effect of different air-polishing powders on the color stability of different types of composite resin restorative materials. MATERIAL AND METHODS: Thirty cylindrical specimens (15×2 mm) were prepared for each of 7 composite resin restorative materials. All specimens were polished with a series of aluminum oxide polishing discs (Sof-Lex). The prepared specimens of each composite resin were randomly divided into 3 groups of 10 specimens each, for control (Group-C) and two air-powder applications (Group-CP: Cavitron Prophy-Jet; Group-PS: Sirona ProSmile prophylaxis powder). A standard air-polishing unit (ProSmile Handly) was used. All specimens were air-powdered for 10 s at 4-bar pressure. The distance of the spray nosel from the specimens was approximately 10 mm and angulation of the nosel was 90°. Specimens were stored in 100 mL of coffee (Nescafe Classic) for 24 h at 37°C. Color measurement of all specimens was recorded before and after exposure to staining agent with a colorimeter (Minolta CR-300). Color differences (∆E*) between the 2 color measurements (baseline and after 24 h storage) were calculated. The data were analyzed with a 2-way ANOVA test, and mean values were compared by the Tukey HSD test (p<0.05). RESULTS: According to the 2-way ANOVA results, composite resin restorative materials, air-polishing powders, and their interaction were statistically significant (p<0.05) For Aelite Aesthetic Enemal, Filtek Z250, Grandio, CeramX Mono, and Quixfil composite resin restorative materials, no significant difference was observed between Group-PS and Group-CP (p>.05) and these groups demonstrated the highest ∆E* values. For Filtek Silorane and IntenS, the highest ∆E* values were observed in Group-PS. The lowest ∆E* values for all composite resin groups were observed in Group-C. When comparing the 7 composite resin restorative materials, Aelite Aesthetic Enemal demonstrated significantly less ∆E* values than the other composite resins tested. The highest ∆E* values were observed in Quixfil. CONCLUSION: Except for Quixfil, all control groups of composite resins that were polished Sof-Lex exhibited clinically acceptable ∆E values (<3.7). Air-polishing applications increased the color change for all composite resin restorative materials tested. Composite restorations may require re-polishing after air-polishing.

Effects of air-polishing powders on color stability of composite resins.

OBJECTIVES: The purpose of this study was to investigate the effect of different air-polishing powders on the color stability of different types of composite resin restorative materials. MATERIAL AND METHODS: Thirty cylindrical specimens (15×2 mm) were prepared for each of 7 composite resin restorative materials. All specimens were polished with a series of aluminum oxide polishing discs (Sof-Lex). The prepared specimens of each composite resin were randomly divided into 3 groups of 10 specimens each, for control (Group-C) and two air-powder applications (Group-CP: Cavitron Prophy-Jet; Group-PS: Sirona ProSmile prophylaxis powder). A standard air-polishing unit (ProSmile Handly) was used. All specimens were air-powdered for 10 s at 4-bar pressure. The distance of the spray nosel from the specimens was approximately 10 mm and angulation of the nosel was 90°. Specimens were stored in 100 mL of coffee (Nescafe Classic) for 24 h at 37°C. Color measurement of all specimens was recorded before and after exposure to staining agent with a colorimeter (Minolta CR-300). Color differences (∆E*) between the 2 color measurements (baseline and after 24 h storage) were calculated. The data were analyzed with a 2-way ANOVA test, and mean values were compared by the Tukey HSD test (p<0.05). RESULTS: According to the 2-way ANOVA results, composite resin restorative materials, air-polishing powders, and their interaction were statistically significant (p<0.05) For Aelite Aesthetic Enemal, Filtek Z250, Grandio, CeramX Mono, and Quixfil composite resin restorative materials, no significant difference was observed between Group-PS and Group-CP (p>.05) and these groups demonstrated the highest ∆E* values. For Filtek Silorane and IntenS, the highest ∆E* values were observed in Group-PS. The lowest ∆E* values for all composite resin groups were observed in Group-C. When comparing the 7 composite resin restorative materials, Aelite Aesthetic Enemal demonstrated significantly less ∆E* values than the other composite resins tested. The highest ∆E* values were observed in Quixfil. CONCLUSION: Except for Quixfil, all control groups of composite resins that were polished Sof-Lex exhibited clinically acceptable ∆E values (<3.7). Air-polishing applications increased the color change for all composite resin restorative materials tested. Composite restorations may require re-polishing after air-polishing.

Alternative treatment procedure in the case of fractured abutment of adhesive bridge: a clinical report.

UNLABELLED: In this case report, an alternative approach was presented for treatment of coronal fracture including pulp of maxillary central incisor, one of the abutments of an adhesive bridge, by using fiber post and tooth's own fractured component. The patient was referred to our clinic with the complaint of pain from the upper right central incisor and mobility of the adhesive bridge in maxillary anterior segment. It was realized that, the upper right central incisor, one of the abutments of the adhesive bridge, had been fractured at middle thirds of the crown including the pulp chamber. After dismounting the adhesive bridge and completion of the root canal treatment, a fiber post was placed into the fractured tooth. The fractured component, adherent to adhesive bridge retainer, was concorded to the fiber post. The whole structure was cemented with adhesive resin. A 1-mm-wide groove was made along the fracture line and restored with composite resin. The patient was evaluated clinically and radiographically at 12 and 30 months after the treatment. CLINICAL SIGNIFICANCE: Adhesive cementation of fractured component by supporting the remaining tooth structure with a fiber post is an inexpensive and conservative treatment alternative when the fractured component is compatible with the remaining tooth structure in cases of tooth fractures including the pulp chamber at anterior segment.

Effects of different polishing techniques on the surface roughness of dental porcelains.

OBJECTIVE: The purpose of this study was to evaluate the effects of different polishing techniques on the surface roughness of dental porcelains. MATERIAL AND METHODS: Fifty-five cylindirical specimens (15x2 mm) were prepared for each feldspathic (Vita VMK 95, Ceramco III) and low-fusing dental porcelain (Matchmaker). Fifty-five specimens of machinable feldspathic porcelain blocks (Vitablocs Mark II), (12x14x18 mm) were cut into 2-mm-thick slices (12x14 mm) with low speed saw. The prepared specimens were divided into 11 groups (n=5) representing different polishing techniques including control ((C) no surface treatment), glaze (G) and other 9 groups that were finished and polished with polishing discs (Sof-Lex) (Sl), two porcelain polishing kits (NTI (Pk), Dialite II (Di)), a diamond polishing paste (Sparkle) (Sp), a zirconium silicate based cleaning and polishing prophy paste (Zircate) (Zr), an aluminum oxide polishing paste (Prisma Gloss) (Pg), and combinations of them. The surface roughness of all groups was measured with a profilometer. The data were analyzed with a 2-way analysis of variance, and the mean values were compared by the Tukey Honestly Significant Difference test (alpha=0.05). RESULTS: For all porcelain material groups, the lowest Ra values were observed in Group Gl, Group Sl, Group Pk, and Group Di, which were not significantly different from each other (p>0.05).When comparing the 4 different porcelain materials, the machinable feldspathic porcelain block group (Mark II) demonstrated statistically significantly less Ra values than the other porcelain materials tested (p<0.05). No significant difference was observed between the VMK 95 and Ceramco III porcelain groups (p=0.919), also these groups demonstrated the highest Ra values. CONCLUSION: Subjected to surface roughness, the surfaces obtained with polishing and/or cleaning-prophy paste materials used alone were rougher compared to the surfaces finished using Sof-lex, Dialite, and NTI polishing kit. Polishing kits and discs were found more effective than the polishing pastes used alone or combined use with Sof-lex discs, thus improving surface smoothness.

Effects of different polishing techniques on the surface roughness of dental porcelains

OBJECTIVE: The purpose of this study was to evaluate the effects of different polishing techniques on the surface roughness of dental porcelains. MATERIAL AND METHODS: Fifty-five cylindirical specimens (15x2 mm) were prepared for each feldspathic (Vita VMK 95, Ceramco III) and low-fusing dental porcelain (Matchmaker). Fifty-five specimens of machinable feldspathic porcelain blocks (Vitablocs Mark II), (12x14x18 mm) were cut into 2-mm-thick slices (12x14 mm) with low speed saw. The prepared specimens were divided into 11 groups (n=5) representing different polishing techniques including control ((C) no surface treatment), glaze (G) and other 9 groups that were finished and polished with polishing discs (Sof-Lex) (Sl), two porcelain polishing kits (NTI (Pk), Dialite II (Di)), a diamond polishing paste (Sparkle) (Sp), a zirconium silicate based cleaning and polishing prophy paste (Zircate) (Zr), an aluminum oxide polishing paste (Prisma Gloss) (Pg), and combinations of them. The surface roughness of all groups was measured with a profilometer. The data were analyzed with a 2-way analysis of variance, and the mean values were compared by the Tukey Honestly Significant Difference test (a=0.05). RESULTS: For all porcelain material groups, the lowest Ra values were observed in Group Gl, Group Sl, Group Pk, and Group Di, which were not significantly different from each other (p>0.05).When comparing the 4 different porcelain materials, the machinable feldspathic porcelain block group (Mark II) demonstrated statistically significantly less Ra values than the other porcelain materials tested (p<0.05). No significant difference was observed between the VMK 95 and Ceramco III porcelain groups (p=0.919), also these groups demonstrated the highest Ra values. CONCLUSION: Subjected to surface roughness, the surfaces obtained with polishing and/or cleaning-prophy paste materials used alone were rougher compared to the surfaces finished using Sof-lex, Dialite, ...

Effect of filler ratio in adhesive systems on the shear bond strength of resin composite to porcelains.

This in vitro study evaluated the effect of six different adhesive systems on the shear bond strength of resin composite to feldspathic and low-fusing porcelains. Sixty porcelain blocks were prepared for each low-fusing (Matchmaker) and feldspathic (MVK95) porcelain specimen. After surface preparation, the porcelain specimens were divided into six groups (n = 10) for different adhesive systems (Adper Prompt L-Pop, QuadrantUnil Bond, Te-Econom, PQ1, One-StepPlus and Prime&Bond NT). After adhesive application, a universal resin composite (FiltekZ250) was condensed on the specimens. The prepared specimens were then stored in distilled water at 37 degrees C for 24 hours, then all the samples were thermal cycled 1000 times between 5 degrees C and 55 degrees C. Shear testing was performed on a universal test machine using a crosshead speed of 0.5 mm/minute. The statistical analysis of the bond strength data included two-way ANOVA. Then, the means were compared by Tukey HSD test (alpha = 0.05). The lowest bond strength was observed in Adper Prompt L-Pop. No statistically significant difference was observed between One-Step Plus and Prime&Bond NT. The highest bond strength was observed in PQ1. When low-fusing or feldspathic porcelain restorations are repaired with resin composite, self-etching adhesive systems may not be indicated. If maximum bond strength is the goal in porcelain resin bonding, adhesive systems that have a high filler ratio should be used.

Effects of polishing procedures on color stability of composite resins

The purpose of this study was to investigate the effect of different polishing methods on color stability of posterior, universal and nanohybrid composite resin restorative materials upon exposure to a staining agent. Twenty-five specimens were prepared for each of 5 different composite resins (Filtek Z250, Filtek P60, Quadrant LC, Grandio and Filtek Supreme). Specimens were divided into 5 groups and different polishing procedures, including polishing discs (Pd), polishing discs then diamond polishing paste (PdP), polishing discs then a liquid polishing system (Biscover) (PdB), and combinations of these (PdPB) were used. Unpolished specimens served as the control (C). The specimens were stored for 48 h in a coffee solution. The color of all specimens was measured before and after exposure with a colorimeter, and total color change (DE*) were calculated. The data were analyzed with a two-way ANOVA and the means were compared by Tukey HSD test (a=0.05). The lowest color difference was observed in the groups PdP and C, while the highest color difference was observed in PdPB, and PdB. When comparing the five different restorative materials, no significant difference was observed between FiltekP60 and FiltekZ250, and these materials demonstrated significantly less color change than Quadrant LC and the nanohybrid materials (Grandio, Filtek Supreme). The posterior (Filtek P60) and universal (Filtek Z250) composite resin restorative materials, which do not contain tetraethyleneglycol dimethacrylate (TEGDMA), were found to be less stainable than the nanohybrid (Grandio, Filtek Supreme) and universal (Quadrant LC) composite resins, which contain TEGDMA. The use of diamond polishing paste after polishing with polishing discs significantly decreased staining when compared to the groups that used polishing discs alone, for all restorative materials tested. The highest color change values were obtained for the specimens that were polished with the...

Effects of polishing procedures on color stability of composite resins.

The purpose of this study was to investigate the effect of different polishing methods on color stability of posterior, universal and nanohybrid composite resin restorative materials upon exposure to a staining agent. Twenty-five specimens were prepared for each of 5 different composite resins (Filtek Z250, Filtek P60, Quadrant LC, Grandio and Filtek Supreme). Specimens were divided into 5 groups and different polishing procedures, including polishing discs (Pd), polishing discs then diamond polishing paste (PdP), polishing discs then a liquid polishing system (Biscover) (PdB), and combinations of these (PdPB) were used. Unpolished specimens served as the control (C). The specimens were stored for 48 h in a coffee solution. The color of all specimens was measured before and after exposure with a colorimeter, and total color change (DeltaE*) were calculated. The data were analyzed with a two-way ANOVA and the means were compared by Tukey HSD test (alpha=0.05). The lowest color difference was observed in the groups PdP and C, while the highest color difference was observed in PdPB, and PdB. When comparing the five different restorative materials, no significant difference was observed between FiltekP60 and FiltekZ250, and these materials demonstrated significantly less color change than Quadrant LC and the nanohybrid materials (Grandio, Filtek Supreme). The posterior (Filtek P60) and universal (Filtek Z250) composite resin restorative materials, which do not contain tetraethyleneglycol dimethacrylate (TEGDMA), were found to be less stainable than the nanohybrid (Grandio, Filtek Supreme) and universal (Quadrant LC) composite resins, which contain TEGDMA. The use of diamond polishing paste after polishing with polishing discs significantly decreased staining when compared to the groups that used polishing discs alone, for all restorative materials tested. The highest color change values were obtained for the specimens that were polished with the Biscover liquid polish system (PdB and PdPB groups).

The effects of children's drinks on the color stability of various restorative materials.

OBJECTIVE: To evaluate the effects of exposure to various children's drinks on the color stability of different esthetic restorative material commonly used in pediatric dentistry. STUDY DESIGN: Cylindrical specimens (15 x 2mm) were prepared from four different restorative materials (Fuji IX, Fuji II LC, Dyract Extra, and Filtek Z250). For each material, 20 specimens were prepared and divided into four groups. Each group was stored in a different solution (distilled water chocolate milk, cola, grape juice) for 24 hours. A colorimeter was used to measure the color of each specimen both before and after staining. Color change (deltaE*) was calculated, and data was analyzed using two-way ANOVA and Tukey HSD tests. RESULTS: For all restorative materials, the lowest deltaE* values were recorded for specimens stored in distilled water (0.42), followed by chocolate milk (0.88), grape juice (3.45) and cola (3.97). Among the four restorative materials tested, Fuji II LC showed the most color change (3.71) and Fuji IX the least (1.33). There were statistically significant differences among above groups (p < 0.05). CONCLUSIONS: DeltaE* values were acceptable for all materials tested, with the exception of Fuji II LC. Therefore, the use of RMGIC should be avoided in anterior restorations in children due to esthetic reasons.

Panoramic radiographic examination of edentulous mouths.

OBJECTIVE: Panoramic radiographs often are the first method used to screen edentulous patients before complete denture therapy. However, routine radiographic examination of edentulous patients is being questioned because of the cumulative effects and cost of radiation exposure. The purpose of this study was to determine the frequency and location of significant radiographic findings in edentulous jaws. METHOD AND MATERIALS: Panoramic radiographs from 338 patients were included in the survey (183 men, 155 women; 676 edentulous arches). The radiographs were evaluated by 1 oral radiology specialist for the following clinically significant radiographic findings: retained root fragments, impacted teeth, radiolucencies associated with cysts, radiopacities associated with localized sclerotic bone formation, location of the mental foramen on the crest, and location of the maxillary sinus close to the crest of the ridge. The data were analyzed using descriptive statistics. RESULTS: Radiographic findings were found in 47.6% (56.5% women, 43.5% men) of the edentulous patients. Fifty-two subjects (29 women, 23 men) had 67 submucosal or intrabony root remains, 50 of which were located in the maxilla. The most frequent finding was retained root fragment, followed by radiopacities. Impacted teeth were found in 11 women and 10 men. In 15 patients the mental foramen was situated at the top of the residual ridge. Of these patients, 13 were women and 2 were men. In 29 patients (14 women, 15 men) the maxillary sinus was close to the crest of the ridge. Six patients (3 women, 3 men) had a bilateral maxillary sinus close to the crest of the ridge. The other 23 patients had a unilateral maxillary sinus close to the crest of the ridge, and except for in 2 men, all were in the left side of the maxilla. CONCLUSION: Routine panoramic examination of the jaws is necessary to detect impacted teeth, retained root fragments, and other radiographic findings that may require treatment before construction of complete dentures.

Color stability of resin composites after immersion in different drinks.

The purpose of this study was to evaluate the discoloration of two nanohybrids, two microhybrids, and a posterior composite resin restorative material upon exposure to different drinks--namely tea, cola, coffee, red wine, and water. The colors of all specimens before and after storage in the solutions were measured by a colorimeter based on CIE Lab system, and the color differences thereby calculated. Data were analyzed by two-way analysis of variance (ANOVA) and Tukey's HSD test. According to ANOVA, the restorative material, staining agent, and their interaction were found to play a statistically significant role (P = 0.0001) in color change. Among the staining agents, water consistently showed the lowest deltaE* value for all materials, whereas red wine showed the highest deltaE* value. In other words, for all the materials tested, their color change in staining agents ranked in this increasing order: water < cola < tea < coffee < red wine. In terms of comparison among the five restorative materials, Filtek P60 and Z250 were observed to manifest less color change than the nanohybrids and Quadrant LC.

Bacterial penetration after obturation with four different root canal sealers.

The aim of this study was to compare bacterial penetration after obturation with lateral compaction technique using four different root canal sealers. This study was performed on 100 teeth including negative control (n = 10), positive control (n = 10), and experimental groups (n = 80). 80 teeth were randomly divided into five groups of 20 teeth each and obturated with AH 26 (A), AH Plus (AP), Sealapex (S), Ketac-Endo (K) root canal sealers. Evaluation was carried out for 60 days. After 30 days of comparing the bacterial penetration values, total penetration was observed in 85% of the Group AP, and group K, 80% of the group S, and 75% of the group A. According to the results of chi(2) test, there was no statistically significant difference observed between any groups (p > 0.05). After 60 days of comparing the bacterial penetration values, total penetration was observed in 100% of the group AP, group K, and group S and 95% of the group A. It may be concluded that under the conditions of this study, there was no difference in the bacterial penetration of the four root canal sealers tested at 30 and 60 days.

Effect of acid etching time and a self-etching adhesive on the shear bond strength of composite resin to porcelain.

UNLABELLED: PURPOSE The purpose of this study was to evaluate the effect of different acid etching times with 9.6% hydrofluoric acid gel and two adhesive systems on shear bond strengths of resin composite to porcelain. MATERIALS AND METHODS: Ninety-eight 7 x 7 x 2 mm feldspathic porcelain blocks (VMK 95, Vita) were prepared. The specimens were divided into 7 groups: 1 control (no surface treatment) and 6 groups acid etched with 9.6% hydrofluoric acid gel for different etching times, including 30 s, 30+30 s, 60 s, 60+60 s, 120 s, and 180 s. Each of the etching time groups was divided into two bonding agent (Single Bond, AdheSE) subgroups (n = 7). Microhybrid composite (Filtek Z250) was condensed using a teflon mold and light polymerized for 20 s on the porcelain specimens. The prepared specimens were then stored in distilled water at 37 degrees C for 24 h before mechanical testing. Shear testing of all groups was performed on a universal testing machine (Lloyd LRX) at a crosshead speed of 0.5 mm/min. The bond strength data were analyzed with two-way ANOVA. The means were compared using the Tukey HSD test (alpha = 0.05). RESULTS: Acid etching time and bonding agent statistically significantly influenced bond strength (p < 0.05). In the Single Bond group, the bond strengths between group 0 (10.48 MPa) and Group 30 (11.17 MPa) did not differ significantly, with these groups exhibiting the lowest bond strength values. The highest bond strength in Single Bond group was observed in group 120 (15.07 MPa) and group 60+60 (15.42 MPa), which did not differ significantly from each other. In the AdheSE group, the bond strengths of group 0 (9.33 MPa) and group 30 (9.49 MPa) did not differ significantly, and these groups exhibited the lowest bond strength values. The highest bond strengths in the AdheSE subgroup were observed in group 120 (14.84 MPa) and group 60+60 (14.96 MPa), which were not significantly different. Comparing the two different adhesive systems, Single Bond exhibited higher bond strength values than did the self-etching adhesive AdheSE. CONCLUSIONS: Acid etching of porcelain with 9.6% hydrofluoric acid gel for 120 s provided adequate bond strength for composite repair with a microhybrid composite. When a porcelain restoration is repaired with composite, Single Bond adhesive should be preferred to the AdheSE self-etching adhesive system.