Elution of monomer from different bulk fill dental composite resins.

OBJECTIVE: The purpose of this study was to evaluate the elution of Bis-GMA, TEGDMA, HEMA, and Bis-EMA monomers from six bulk fill composite resins over four different time periods, using HPLC. METHODS: Six different composite resin materials were used in the present study: Tetric Evo Ceram Bulk Fill (Ivoclar Vivadent, Amherst, NY), X-tra Fill (VOCO, Cuxhaven, Germany), Sonic Fill (Kerr, Orange, CA, USA), Filtek Bulk Fill (3M ESPE Dental Product, St. Paul, MN), SDR (Dentsply, Konstanz, Germany), EQUIA (GC America INC, Alsip, IL). The samples (4mm thickness, 5mm diameter) were prepared and polymerized for 20s with a light emitted diode unit. After fabrication, each sample was immediately immersed in 75wt% ethanol/water solution used as extraction fluid and stored in the amber colored bottles at room temperature. Ethanol/water samples were taken (0.5mL) at predefined time intervals:10m (T1), 1h (T2), 24h (T3) and 30 days (T4). These samples were analyzed by HPLC. The obtained data were analyzed with one-way ANOVA and Tukey HSD at significance level of p<0.05. RESULTS: Amount of eluted Bis-EMA and Bis-GMA from Tetric Evo Ceram Bulk Fill and amount of eluted TEGDMA and HEMA from X-tra Fill higher than others composites (p<0.05). SIGNIFICANCE: Residual monomers were eluted from bulk fill composite resins in all time periods and the amount of eluted monomers was increased with time.

Effects of contemporary orthodontic composites on tooth color following short-term fixed orthodontic treatment: a controlled clinical study.

BACKGROUND/AIM: To determine the color alterations of natural teeth associated with different orthodontic composites used in comprehensive short-term treatment. MATERIALS AND METHODS: Twenty-two patients were treated with fixed appliances and 22 untreated subjects were also evaluated. Lower incisors were bonded with different orthodontic composites: 42 with Grengloo, 41 with Light Bond, 31 with Kurasper F, and 32 with Transbond XT. The color parameters of the Commission Internationale de l'Eclairage (CIE) were measured for each tooth with a spectrophotometer. Color assessment in relation to time, adhesive material, and their interaction was made with 2-way mixed analysis of variance (ANOVA) and 1-way ANOVA for the color differences (ΔE*). Further analyses were done using Tukey's honestly significant difference tests and paired-samples t-tests. RESULTS: The color of teeth was affected by treatment. The mean L* and a* values increased, whereas the mean b* values decreased. Total color differences of teeth demonstrated visible color changes clinically after treatment, ranging from 1.12 to 3.34 ΔE units. However, there were no significant differences for color of enamel. CONCLUSION: Teeth may be discolored with fixed appliances during treatment. Moreover, contemporary orthodontic composites have similar effects of enamel discoloration.

Effect of accelerated aging on the bonding performance of fluoridated adhesive resins.

The purpose of this study was to investigate the dentin bond durability of a one-step, fluoride-containing, glass ionomer-based adhesive system, Reactmer Bond (RB), and that of a two-step, fluoride-containing, self-etch adhesive system, Clearfil Protect Bond (CPB). Enamel was removed from the occlusal surfaces of teeth, and flat dentin surfaces were entirely covered with a composite resin following the application of an adhesive material (n=10). After specimens were sectioned into rectangular sticks of 0.87 ± 0.03 mm(2), the sticks were randomly assigned into two accelerated aging time period groups: 1 week or 1 year. Microtensile bond strengths were determined. Bond strength of RB increased significantly after 1 year (1 week=27.80 ± 10.57 MPa versus 1 year=36.93 ± 14.38 MPa) (p<0.05). In contrast, there was no significant difference in bond strength between the two time periods for CPB (1 week=51.74 ± 17.8 MPa versus 1 year=56.03 ± 18.85 MPa) (p>0.05). Both fluoride-containing adhesives seemed to demonstrate reliable bonding performance after 1 year of accelerated aging in water.

Conversion degrees of resin composites using different light sources.

OBJECTIVE: The objective of this study was to compare the conversion degree of six different composite materials (Filtek Z 250, Filtek P60, Spectrum TPH, Pertac II, Clearfil AP-X, and Clearfil Photo Posterior) using three different light sources (blue light-emitting diode [LED], plasma arc curing [PAC], and conventional halogen lamp [QTH]). METHODS: Composites were placed in a 2 mm thick and 5 mm diameter Teflon molds and light cured from the top using three methods: LED for 40 s, PAC for 10 s, and QTH for 40 s. A Fourier Transform Infrared Spectroscopy (FTIR) was used to evaluate the degree of conversion (DC) (n=5). The results were analyzed with two-way analysis of variance and Tukey HSD test. RESULTS: DC was significantly influenced by two variables, light source and composite (P<.05). QTH revealed significantly higher DC values than LED (P<.05). However, there were no significant differences between DC values of QTH and PAC or between DC values of LED and PAC (P>.05). The highest DC was observed in the Z 250 composite specimens following photopolymerization with QTH (70%). The lowest DC was observed in Clearfil Photo Posterior composite specimens following photo-polymerization with LED (43%). CONCLUSIONS: The DC was found to be changing according to both light sources and composite materials used. Conventional light halogen (QTH) from light sources and Filtek Z 250 and Filtek P 60 among composite materials showed the most DC performance.

Effect of cavity preparation techniques and different preheating procedures on microleakage of class V resin restorations.

OBJECTIVES: This study aimed to evaluate the extent of microleakage of a single type of composite resin (Clearfil Majesty Posterior, Kuraray, Osaka, Japan) following different preheating procedures in Class V cavities prepared with a diamond bur or Er:YAG (erbium: yttrium aluminum garnet) laser. METHODS: The study randomly divided 72 permanent molar teeth divided into eight groups (n = 9): G1: Diamond bur-unheated composite resin (room temperature-24 ºC); G2: Diamond bur-composite preheated to 37 ºC; G3: Diamond bur-composite preheated to 54 ºC; G4: Diamond bur-composite preheated to 68 ºC; G5: Er:YAG laser-unheated composite resin (room temperature-24 ºC); G6: Er:YAG laser-composite preheated to 37 ºC; G7: Er:YAG laser-composite preheated to 54 ºC; and G8: Er:YAG laser-composite preheated to 68 ºC. The specimens were subjected to a thermal cycling regimen of 5000 cycles between 5 and 55 ºC; then they were immersed in a solution of 0.5% basic fuchsin dye for 24 hours. The dyed specimens were sectioned in the buccolingual direction and dye penetration was scored in a blinded manner using a five-point qualitative scale. Microleakage scores were analyzed with the Kruskall-Wallis, Mann-Whitney U, and Wilcoxon tests. RESULTS: There were no statistically significant differences between the microleakages of composite applied to cavities prepared by either the Er:YAG laser or diamond bur (P>.05). Statistical analysis revealed significant differences between the enamel and dentin in all restorations (P<.001). However, there were no significant differences among the preheated groups (P>.05). CONCLUSIONS: For all groups, microleakage values were higher at gingival margins than at occlusal margins. The use of the Er:YAG laser at different preheating procedures did not influence the marginal sealing in Class V composite resin restorations.

Cytotoxicity evaluation of dentin bonding agents by dentin barrier test on 3-dimensional pulp cells.

OBJECTIVE: The aim of this study was to evaluate the effects of 4 dentin-bonding agents on the cell viability of bovine derived cells. STUDY DESIGN: Cytotoxicity of dentin-bonding agents (G-Bond [GB], Adper Prompt Self-Etch [APSE], Clearfil DC Bond System [CDCB], and Quadrant University-1-Bond [UB]) was analyzed with a dentin barrier test device using 3-dimensional (3D) pulp cell cultures. A commercially available cell culture perfusion chamber was separated into 2 compartments using a 500 µm dentin disk. The 3D cultures were placed on a dentin disk and held in place with a special biocompatible stainless steel holder. Test materials were introduced into the upper compartment in direct contact with the cavity side of the dentin disks according to the manufacturer's instructions. Subsequently, the pulpal part of the perfusion chamber containing the cell cultures was perfused with a medium (2 mL/h). After an exposure period of 24 hours, cell survival was determined by using the MTT assay. Statistical analyses were performed using the Mann-Whitney U test. RESULTS: In the dentin barrier test, cell survival rates of UB and CDCB were similar to the control group (P > .05). However, all other tested materials were cytotoxic for the 3D pulp-derived cell cultures (P < .05). CONCLUSIONS: Dentin-bonding agents include biologically active ingredients and may modify pulp cell metabolism when the materials are used in deep cavities in spite of a dentin barrier. If these adhesive agents are used in deep cavities, a biocompatible cavity liner should be used.

Polymerization capacity of orthodontic composites analyzed by Fourier transform infrared spectroscopy.

INTRODUCTION: The aim of this in-vitro study was to analyze the polymerization capacity of 5 orthodontic composites by determining the degree of monomer conversion (DC). METHODS: Fourier transform infrared spectroscopy was used to evaluate the DC of the orthodontic composites immediately after polymerization and after storage in artificial saliva at 37°C ± 1°C for 30 days. The resin-based adhesive composites investigated were Bisco Ortho (Bisco, Schaumburg, Ill), Heliosit Orthodontics (Ivoclar, Schaan, Liechtenstein), Kurasper F (Kuraray, Okayama, Japan), Light Bond (Reliance Orthodontic Products, Itasca, Ill), and Transbond XT (3M Unitek, Monrovia, Calif), cured with Elipar FreeLight 2 (3M ESPE, St Paul, Minn) for the testing of the DC values. Fifty cylindrical specimens were manufactured in molds. The data were analyzed by 2-factor analysis of variance (ANOVA) and Tukey HSD test. RESULTS: According to 2-way ANOVA, the DC was significantly influenced by composite type (P <0.05); after 30 days, there were no differences among the composite types for the DC. The interaction of orthodontic composites and time played a statistically significant role in the DC (P <0.05), but there was no statistically significant influence of time for the DC (P >0.05). CONCLUSIONS: The DC was found to change according to composite materials used, and Bisco Ortho showed the most DC performance. The DC of orthodontic composites is a complex process that is affected not only by inorganic filler content of the composite but also the monomer type and many other factors. Sufficient DC values of 5 commercially available orthodontic composites can be achieved with a new-generation light-emitting diode curing light.

The effect of different surface treatments on roughness and bond strength in low fusing ceramics.

The aim of this study was to evaluate the influence of different surface treatments (air abrasion, acid etching, and laser irradiation) on the surface roughness and bond strength of a low fusing ceramic. Thirty-six discs of low fusing ceramic (Finesse, Ceramco) were prepared (10 mm in diameter and 2 mm in thickness) according to the manufacturer's instructions. Specimens were divided into three groups (n = 12), and the following treatments were performed: Air abrasion with alumina particles (50 µm), acid etching with 5% HF and Nd:YAG laser irradiation (distance: 1 mm, 100 mJ, 20 Hz, 2 W, and 141.54 J/cm(2)). Following determination of surface roughness (R(a)) by profilometry, specimens were examined with scanning electron microscopy (SEM). The luting cement (Clearfil Esthetic Cement) was bonded to the ceramic specimens using Teflon tubes. After 24 h of water storage, shear bond strength test was performed using a universal testing machine at a crosshead speed of 1 mm/min. The data were analyzed with two-way analysis of variance (ANOVA) and Tukey HSD tests (α = .05). Two-way ANOVA indicated that surface roughness was significantly affected by surface treatments (p < .001). Tukey honestly significant difference (HSD) indicated that the air abrasion group had a significantly higher mean value (p < .05) than the other groups. Shear bond strength was significantly affected by surface treatments (p < .001). Tukey HSD indicated that the air abrasion group had a significantly higher mean value (p < .05) than the other groups. No significant difference was found between the acid-etching and laser-irradiation groups (p > .05). The SEM image of the laser irradiation surface appeared to be relatively smooth as compared to the images of other the groups. Air abrasion of low-fusing porcelain surfaces was effective in improving the bond strength as compared to the acid-etching and laser-irradiation methods.

Effects of laser and acid etching and air abrasion on mineral content of dentin.

The aim of this study was to evaluate the mineral content of dentin prepared using an Er,Cr:YSGG laser at four different power settings, acid etching, and air abrasion. The study teeth comprised 35 molars which were randomly divided into seven equal groups. The occlusal third of the crowns were cut with a slow-speed diamond saw. The groups were as follows: group A, control group; group B, dentin etched with 35% buffered phosphoric acid for 30 s; group C, dentin abraded at 60 psi with 50-µm aluminium oxide for 1 s; groups D-G, dentin irradiated with the Er,Cr:YSGG laser at 1.50 W (group D), 2.25 W (group E), 3.00 W (group F), and 3.50 W (group G). The levels of Mg, P, Ca, K and Na in each dentin slab were measured by inductively coupled plasma-atomic emission spectrometry (ICP-AES). Data were analysed by one way analysis of variance and Tukey HSD tests. There were no significant differences between the groups in the levels of Ca, P and Na, and the Ca/P ratio (p>0.05); however, there were significant differences in the levels of K (p<0.001) and Mg (p=0.13). In addition, the levels of Mg in the air abrasion group were higher than in the other groups (p<0.01). Etching with the Er,Cr:YSGG laser system, air abrasion and acid etching did not affect the levels of Ca, P and Na, or the Ca/P ratio, in the dentin surface.

Effects of staining solutions on the discoloration of orthodontic adhesives: an in-vitro study.

INTRODUCTION: Our aim was to evaluate the effects of staining solutions on the discoloration of orthodontic adhesives. METHODS: Six orthodontic adhesives were investigated (Transbond XT [3M Unitek, Monrovia, Calif, USA], Heliosit Orthodontic [Ivoclar Vivadent, Liectenstein], Light Bond [Reliance Orthodontic Products, Itasca, IL, USA], Bisco Ortho [Bisco, Schamburg, IL, USA], Quick Cure [Reliance Orthodontic Products, Itasca, IL, USA], and Filtek Supreme XT [3M ESPE, St Paul, Minn, USA]), and 5 beverages (tea, cola, coffee, red wine, and yogurt). Sixty specimens were prepared. Five specimens from each group were stored in each of the 5 staining solutions. The 5 remaining specimens from each group served as the controls and were stored in distilled water. The specimens were immersed in staining solutions and water at 37°C ± 1°C for 5 days. The test period was 25 days. Before and after the test period, color measurements were carried out with a spectrophotometer, and color changes (ΔE∗) were calculated. Statistical differences were evaluated by using analysis of variance (ANOVA) and the Tukey HSD tests. RESULTS: Adhesive materials, staining agents, and their interactions were found to play statistically significant roles (P < 0.001) in color changes. Among the adhesive materials, the Light Bond water control group consistently showed the lowest ΔE∗ value for all materials, and the Filtek Supreme XT group showed the highest ΔE∗ value for all materials. After the in-vitro experimental process for staining solutions and water, unsatisfactory color stability was observed for the conventional adhesive systems except for Light Bond, Transbond XT, and Bisco Ortho water control group (ΔE∗ > 3.7), respectively. CONCLUSIONS: In esthetically critical areas, discoloration of adhesive materials for fixed orthodontics can cause patient dissatisfaction. Orthodontic composites will discolor from staining beverages during their lifespan.

Influence of different tooth types on the bond strength of two orthodontic adhesive systems.

The aim of this investigation was to evaluate the effects of different tooth types on the shear bond strength (SBS) of two orthodontic resin adhesive systems in vitro. Two hundred extracted sound human teeth were used in the study. Ten teeth of each tooth type were the mounted in acrylic resin leaving the buccal surface of the crowns parallel to the base of the moulds. In each experimental group, the adhesives (Transbond XT and Light Bond) were applied to the etched enamel surfaces. The orthodontic composite resins were then applied to the surface in cylindrical-shaped plastic matrices. For SBS testing, a force transducer (Ultradent) was applied at a crosshead speed of 1 mm/minute at the interface between the tooth and composite until failure occurred. Data were analysed using two-way analysis of variance (ANOVA), Kruskal-Wallis one-way ANOVA, a Bonferroni adjusted Mann-Whitney U-test, and an independent t-test. Generally, it was found that tooth type had a significant effect on SBS (P < 0.05) with Light Bond showing a higher SBS than Transbond XT (P < 0.05). The highest bond strengths were observed for the upper central incisor and lower molars with Light Bond (P < 0.05) and the lowest mean bond strengths for the upper molars and lower canine with Transbond XT (P <0.05). The results demonstrated that enamel SBS was significantly altered by both tooth type and adhesive system. Thus, the findings of this study confirm that enamel bond strength is not uniform for all teeth. These results may also explain the variability in the enamel-bonding efficacy of adhesives.

Microtensile bond strength of cad-cam and pressed-ceramic inlays to dentin.

OBJECTIVES: CAD-CAM system is popular because of high esthetic and short fabrication time. But, there is limited information available about the microtensile bonding of luting cements to CAD-CAM inlays and to dentin. The aim of this study was to examine the bond strength of CAD-CAM (Cerec 3) and pressed-ceramic (IPS Empress 2) inlays to dentin surface by microtensile testing using two luting cements. MATERIALS AND METHODS: Standardized mesio-occlusal cavities were made in forty extracted molar teeth. An occlusal reduction of 2 mm was made; the bucco-lingual width of the proximal boxes was 4 mm, the occlusal width 3 mm and the depth of the pulpal and axial walls 2 mm. The proximal boxes were extended 1 mm below the cemento-enamel junction. Teeth were randomly assigned to 2 groups to evaluate the bonding of 2 ceramic systems, Cerec 3 (Group I) and IPS Empress 2 (Group II), to dentin. Each of the 2 groups were further divided into 2 luting cement groups, Panavia F (Group A) and Variolink II (Group B). After cementation, the teeth were sectioned into two 1.2x1.2 mm wide 'I' shape sections. The specimens were then subjected to microtensile testing at a crosshead speed of 1 mm/min. Two-way ANOVA and Tukey HSD tests were used to evaluate the results. RESULTS: The mean microtensile bond strengths of Cerec 3 and IPS Empress 2 bonding to dentin with luting agents in MPa were Panavia F (13.98+/-3.44), Variolink II (14.19+/-3.12) and Panavia F (15.12+/-3.15), Variolink II (15.45+/-3.08) respectively. No significant differences were found among the 2 ceramic systems (P>.05) and 2 luting cements with regard to dentin bond strengths (P>.05). CONCLUSIONS: There was no difference found between the dentin bond strength of the Cerec 3 and IPS Empress 2 inlays cemented with two luting cements.

Two-year color changes of light-cured composites: influence of different light-curing units.

This study determined color changes in a composite cured with various types of curing units after two years. A hybrid (Clearfil AP-X) composite was cured with a conventional halogen, a high intensity halogen, a plasma arc and a light emitting diode unit. The specimens were stored in light-proof boxes after the curing procedure to avoid further exposure to light and stored in 37 degrees C in 100% humidity. Colorimetric values of the specimens immediately after curing and after two years were measured using a colorimeter. The CIE 1976 L*a*b color system was used to determine color differences. Differences from baseline were calculated as deltaE*ab. Data were analyzed with two-way analysis of variance (p<0.05). The deltaE*ab values varied significantly, depending on the curing unit used. The specimens cured with a plasma arc curing unit induced significantly higher color changes than any other specimen and the color differences were also visually appreciable by the non-skilled operator (deltaE*ab >2.5). The specimens cured with a high intensity halogen curing unit produced the lowest color change; however, there were no statistically significant differences among the color changes of specimens cured with conventional halogen, high intensity halogen and the light emitting diode unit, and the color changes were not clinically relevant (deltaE*ab <2.5). The results of this study suggest that composite materials undergo measurable changes due to curing unit exposure. The specimens cured with a plasma arc light showed the highest color changes as compared to specimens cured with other curing units.

Degree of conversion and surface hardness of resin cement cured with different curing units.

OBJECTIVE: The aim of this study was to evaluate the degree of conversion and Vickers surface hardness of resin cement under a simulated ceramic restoration with 3 different curing units: a conventional halogen unit, a high-intensity halogen unit, and a light-emitting diode system. METHODS AND MATERIALS: A conventional halogen curing unit (Hilux 550) (40 s), a high-intensity halogen curing unit used in conventional and ramp mode (Optilux 501) (10 s and 20 s, respectively), and a light-emitting diode system (Elipar FreeLight) (20 s, 40 s) were used in this study. The dual-curing resin cement (Variolink II) was cured under a simulated ceramic restoration (diameter 5 mm, height 2 mm), and the degree of conversion and Vickers surface hardness were measured. For degree of conversion measurement, 10 specimens were prepared for each group. The absorbance peaks were recorded using the diffuse-reflection mode of Fourier transformation infrared spectroscopy. For Vickers surface hardness measurement, 10 specimens were prepared for each group. A load of 200 N was applied for 15 seconds, and 3 evaluations of each of the samples were performed. RESULTS: Degree of conversion achieved with Optilux 501 (20 s) was significantly higher than those of Hilux, Optilux 501 (10 s), Elipar FreeLight (20 s), and Elipar FreeLight (40 s). For Vickers surface hardness measurement, Optilux 501 (20 s) produced the highest surface hardness value. No significant differences were found among the Hilux, Optilux 501 (10 s), Elipar FreeLight (20 s), and Elipar FreeLight (40 s). CONCLUSION: The high-intensity halogen curing unit used in ramp mode (20 s) produced harder resin cement surfaces than did the conventional halogen curing unit, high-intensity halogen curing unit used in conventional mode (10 s) and light-emitting diode system (20 s, 40 s), when cured through a simulated ceramic restoration.

Microtensile bond strength of two resin composite materials placed with direct and indirect techniques under simulated pulpal pressure.

PURPOSE: The aim of this in vitro study was to compare the dentin bond strength of directly and indirectly inserted composite restorations. MATERIALS AND METHODS: Twenty extracted human mandibular molars were prepared to form a flat occlusal dentin surface using an Isomet saw under water. Five-mm-thick composite restorations (Filtek Z 250 and Clearfil AP-X) were placed on the dentin surfaces by direct or indirect techniques. The direct restorations were bonded with Single Bond and Clearfil SE Bond bonding agents. Indirect restorations were cemented with two composite luting cements (3M Opal Luting Cement and Panavia F). All restorative procedures were applied under simulated pulpal pressure (15 cm H2O). Each tooth was then vertically sectioned with an Isomet saw through the composite buildups and the dentin. Thus, for microtensile testing, 0.65 x 0.65 mm specimens were obtained from pulpal and remote dentin regions. The results were analyzed according to the regional dentinal surfaces (pulpal and remote dentin). For statistical analyses, two-way ANOVA and Duncan post-hoc tests were used (p < 0.05). RESULTS: Direct application of Clearfil AP-X showed that tensile bond strengths were higher than those obtained for directly and indirectly applied Filtek Z 250 and indirectly applied Clearfil AP-X. No significant difference in tensile bond strengths was demonstrated between pulpal and remote dentin (p > 0.05). CONCLUSION: It is concluded that the bond strengths of resin luting cements to dentin need further improvement.

Effect of tooth age on microtensile bond strength of two fluoride-releasing bonding agents.

PURPOSE: The purpose of this study was to evaluate the effect of age of dentin and enamel on the microtensile bond strengths of a glass-ionomer based, all-in-one, single-step, self-etching adhesive system (Reactmer Bond, RB) and an antibacterial, two-step self-etching primer system (ABF Bond, ABF). MATERIALS AND METHODS: Extracted molars from 3 age groups (20 to 25, 35 to 40, and 50 to 55 years) were used. Enamel was removed from the occlusal surfaces of the teeth, and the entire flat surfaces were covered with composite resin (4 mm in height) following application of bonding agents. The bonded specimens were thinly sectioned parallel to the long axis of the tooth into 0.87 +/- 0.03 mm2 rectangular sections, resulting in 6 to 7 enamel specimens and 10 to 15 dentin specimens per tooth. The specimens were subjected to the microtensile test at a crosshead speed of 1 mm/min. The data were analyzed by Univariate ANOVA, Tukey HSD, and regression analysis. RESULTS: The bond strength of ABF to both enamel and dentin was higher than the bond strength of RB. Bond strengths of ABF to dentin were significantly higher than the bond strengths to enamel (p < 0.05). The 35- to 40-year age group of ABF showed the highest bond strength of all. In RB dentin groups, 34% of specimens showed cohesive failure in composite resin material. CONCLUSION: Bond strength values to enamel were not affected by age of teeth in either bonding system. Dentinal bond strength using ABF changed according to age of the teeth. Age did not affect bond strength values of RB to dental hard tissues. However, the high number of cohesive failures in Reactmer paste indicated low tensile strength of the material.

An interdisciplinary approach for restoring function and esthetics in a patient with amelogenesis imperfecta and malocclusion: a clinical report.

This clinical report describes an interdisciplinary approach for the coordinated treatment of a patient diagnosed with amelogenesis imperfecta and malocclusion. The patient's functional and esthetic expectations were successfully met with interdisciplinary treatments, including orthodontics, porcelain laminate veneers, metal-ceramic fixed partial dentures, and direct composite restorations.

Temperature rise during adhesive and resin composite polymerization with various light curing sources.

This study evaluated the temperature rise in two different adhesive (Clearfil SE Bond [CSEB] and EBS-Multi [EBSM]) and composite systems (Clearfil AP-X [CAPX,] Pertac II [PII]) by the same manufacturer when illuminated by four different light sources: Light-emitting diode (LED), Plasma arc curing (PAC), high intensity quartz tungsten halogen (HQTH) and quartz tungsten halogen (QTH). Forty dentin disks were prepared from extracted premolars. These dentin disks were placed in apparatus developed to measure temperature rise. Temperature rise during photopolymerization of adhesive resin and resin composite was then measured. The mean values of temperature increases for adhesive and resin composites did not differ significantly (p=0.769). The highest temperature rise was observed during photopolymerization of EBSM with PAC (5.16 degrees C) and HQTH (4.28 degrees C), respectively. Temperature rise values produced by QTH (1.27 degrees C - 2.83 degrees C for adhesive resin; 1.86 degrees C - 2.85 degrees C for resin composite) for both adhesive and resin composites were significantly lower than those induced by PAC and HQTH (p<0.05). However, these values were significantly higher than those produced by LED (1.16 degrees C - 2.08 degrees C for adhesive resin; 1.13 degrees C - 2.59 degrees C for resin composite). Light sources with high energy output (PAC and HQTH) caused significantly higher temperature rise than sources with low energy output (QTH and LED). However, in this study, no temperature rises beneath 1-mm dentin disk exceed the critical 5.6 degrees C value for pulpal health.

In vitro assessment of temperature change in the pulp chamber during cavity preparation.

STATEMENT OF PROBLEM: Tooth preparation with a high-speed handpiece may cause thermal harm to the dental pulp. PURPOSE: This in vitro study evaluated the temperature changes in the pulp chamber during 4 different tooth preparation techniques and the effects of 3 different levels of water cooling. MATERIAL AND METHOD: The tip of a thermocouple was positioned in the center of the pulp chamber of 120 extracted Shuman premolar teeth. Four different tooth preparation techniques were compared: (1) Low air pressure plus low load (LA/LL), (2) low air pressure plus high load (LA/HL), (3) high air pressure plus low load (HA/LL), and (4) high air pressure plus high load (HA/HL) in combination with 3 different water cooling rates. Control specimens were not water cooled; low water cooling consisted of 15 mL/min, and high water cooling consisted of 40 mL/min. Twelve different groups were established (n=10). An increase of 5.5 degrees C was regarded as critical value for pulpal health. The results were analyzed with a 3-factor ANOVA and Bonferroni adjusted Mann Whitney U test (alpha=.004). RESULTS: For all techniques without water cooling (LA/LL/0, LA/HL/0, HA/LL/0, and HA/HL/0), the average temperature rise within the pulpal chamber exceeded 5.5 degrees C during cavity preparation (7.1 degrees C; 8.9 degrees C; 11.4 degrees C, and 19.7 degrees C, respectively). When low water cooling was used with high air pressure and high load technique (HA/HL/15), the average temperature rise exceeded 5.5 degrees C limit (5.9 degrees C). However, when high water cooling (LA/LL/40, LA/HL/40, HA/LL/40, and HA/HL/40) was utilized, the critical 5.5 degrees C value was not reached with any air pressure or load (3.1 degrees C, 2.8 degrees C, 2.2 degrees C, and -1.8 degrees C, respectively). CONCLUSION: Within the limitations of this in vitro study, the results indicate that reducing the amount of water cooling or increasing air pressure and load during cavity preparation increased the temperature of the pulp chamber in extracted teeth.

Effect of NaOCl on bond strengths of bonding agents to pulp chamber lateral walls.

The objective of this study was to evaluate the effects of 5% NaOCl on bond strengths of four bonding systems-Clearfil SE Bond, Prompt L-Pop, Prime&Bond NT, and Scotchbond Multi Purpose Plus-to pulp chamber mesial walls. Forty mandibular third molar teeth were used in the study. The pulp chambers of the first 20 teeth were restored with bonding agents and composite resins after 5% NaOCl irrigation, and the remaining teeth were restored without 5% NaOCl treatment. Each bonding group had five teeth. Three rectangular thin sticks (1+/-0.03 mm) were obtained from the mesial wall of restored pulp chambers by horizontal sectioning. In general, NaOCl application decreased the bond strength values of the bonding agents. Both Clearfil SE Bond and Prompt L-Pop without NaOCL showed higher bond strength values than the other bonding groups. In NaOCl-applied groups, Clearfil SE Bond had the highest bond strength. It can be concluded that self-etching bonding systems are more successful than the other systems in bonding to pulp chamber dentinal wall and that NaOCl reduces bond strength.