Five-year results of nonsurgical treatment to manage severe generalized aggressive periodontitis.

It is challenging for clinicians to carry out successful periodontal therapy and maintain a full dentition in young patients with generalized bone loss of 90%. Due to advanced attachment loss and the young age of patients, fixed or removable prosthetic treatment options are compromised. Implant therapy would be complex and expensive. The presented case shows the successful conservative periodontal therapy of advanced generalized aggressive periodontitis in a 29-year-old female. A conservative approach was applied and maintained all teeth with patient satisfaction both functionally and esthetically. This case was followed over 5 years.

Durability of fiber post-to-composite bonds achieved by physical vapor deposition and tribochemical silica coating.

PURPOSE: To evaluate post-to-composite bonds in terms of their durability, achieved either by physical vapor deposition (PVD) or tribochemical silica coating (TSC) compared to coupling strategies for fiber posts at chairside. MATERIALS AND METHODS: Thirty uncoated fiber posts (DT Light) each were either left untreated (control) or silanized with a one-bottle (Monobond Plus) or a two-bottle (Clearfil SE Bond/Porcelain Bond Activator) silane at the chairside. Thirty coated fiber posts each had already been silica coated and silanized by the manufacturer using PVD (DT Light SL) or TSC (DentinPost Coated) deposition techniques. Surface analysis was carried out by profilometry and x-ray microanalysis. All the posts were surrounded by 2-mm-thick disks of a dual-curing composite resin (MultiCore Flow). After water storage for 24 h at 37°C, the specimens in each group were randomly divided into three subgroups (n=10) and subjected to 0, 1500, and 20,000 thermocycles (5°C to 55°C) prior to push-out testing. Failure modes were evaluated by optical and scanning electron microscopy. The statistical significance was determined with two-way ANOVA, the Student-Newman-Keuls test, and Fisher's exact test. RESULTS: The conditioned posts had significantly higher interfacial bond strengths than the control posts after thermocycling (p<0.05). Extended thermocycling significantly reduced the interfacial strength of chairside silanized posts (p<0.05). This effect was not significant with industrially coated posts (p>0.05). Coatings deposited by TSC reached the highest bond values (p<0.05) and showed predominantly adhesive failures in the form of coating delamination (p<0.0001). In contrast, the other coupling strategies showed significantly lower values and adhesive failures between the post and the composite. CONCLUSION: PVD and TSC techniques enhanced the bond durability of fiber posts. TSC led to a superior post-tocomposite bond, probably based on more effective micromechanical adhesion due to the higher surface roughness.

Lamella settlers for storm water treatment - performance and design recommendations.

Three lamella settlers were monitored over a period of 4 years. The main objective was to determine removal efficiencies for total suspended solids and associated pollutants. For this purpose a new sampling method based on large volume solid samplers was developed allowing a detailed analysis of solids. With regard to total suspended solids the average removal efficiency of the plants range from 49 to 68%. Similar values could be achieved for phosphorus and heavy metals mainly because of the high portion of fine particles in treatment plants' influent. A clear dependency between solid removal efficiency and the parameters maximum surface load and influent concentration could be observed on a single event basis. The aggregation of all findings result in a recommended maximum design surface loading rate (SLR) of 4 m/h. A solid removal rate of 50%, which is defined as minimum long-term efficiency, can be achieved safely at this SLR. In addition to the definition of the maximum SLR, a proper dissipation of the inflow energy and an equal collection of the clear water above the lamellas turn out to be essential.

Which self-etch bonding systems are suitable for which clinical indications?

Self-etch bonding systems are promoted as a time-saving and user-friendly alternative to etch-and-rinse bonding systems. Self-etch adhesives are characterized by a relatively mild etching effect, resulting in a relatively low incidence of postoperative hypersensitivity. On the other hand, their mild etching effect causes a reduction in bond strength to enamel compared to that achieved with phosphoric acid etching. All-in-one adhesives still suffer from less-than-optimal initial bond strengths and from inadequate durability of the bond. Future developments need to focus on the elimination of water deposits along the adhesive interface of all-in-one adhesives. While self-etch adhesives may yield acceptable results when applied in combination with light-cured composite resin, their acidic monomers inhibit the polymerization of auto-cured and dual-cured composite resins. Unfortunately, most "self-cure" or "dual-cure" activators do not overcome this problem. This incompatibility has to be taken into consideration when using self-etch adhesives for adhesive cementation and for core build-up restorations. When assessing self-etch bonding systems, it should be noted that they do not represent a homogenous category of materials but rather comprise a great variety of different types of products, each with specific strengths and weaknesses.

Reconsidering the double etching of enamel: do self-etching primers contaminate phosphoric acid-etched enamel?

PURPOSE: To evaluate the composite-to-enamel bond following double etching of the enamel using phosphoric acid and different self-etching (SE) bonding systems with and without the application of their respective acidic primers. MATERIALS AND METHODS: The enamel surfaces of 90 human molars were ground (600 grit) flat and randomly divided into nine groups (n = 10). Three two-step SE systems (AdheSE, ASE; Clearfil SE Bond, CSE; OptiBond Solo Plus SE, OSE) were tested, both with and without primer application on enamel pre-etched with phosphoric acid under dry bonding conditions. As the controls, the SE systems were applied according to their original directions without pre-etching. All the specimens were built up with a microhybrid composite resin (Arabesk Top). After water storage for 24 h at 37°C, the bonded specimens were sheared to failure in the Zwicki 1120. Etching and failure patterns were evaluated using a scanning electron microscope (SEM). Shear bond strength was analyzed with two-way ANOVA and Tukey's test. Failure modes were analyzed with Fisher's exact test. RESULTS: Without pre-etching, CSE showed significantly higher bond strengths than ASE and OSE (p < 0.05). Enamel etching prior to the application of the SE systems tended to result in higher bond strengths, but significantly increased the values only for ASE (p < 0.05). Contamination of the pre-etched enamel with the SE primer decreased the bond strength by values of 19% for ASE (p > 0.05), 36% for CSE (p < 0.05), and 75% for OSE (p < 0.05). SEM analysis showed that omission of the priming step significantly increased the number of cohesive failures within the resin for OSE (p < 0.0001). CONCLUSION: Additional etching with phosphoric acid before the application of SE systems does not necessarily result in better enamel bonding, since unavoidable primer contamination of the pre-etched enamel was shown to significantly reduce the bond strength for two of the three systems tested.

Antibacterial activity of calcium hydroxide and chlorhexidine containing points against Fusobacterium nucleatum and Parvimonas micra.

OBJECTIVE: Up to 90% of the flora of an infected root canal consists of obligate anaerobic bacteria. However, most studies have centred on microaerophiles. This quantitative assay investigated the antibacterial effects against Fusobacterium nucleatum and Parvimonas micra of gutta-percha (GP) points containing either calcium hydroxide (Ca(OH)(2)) or chlorhexidine (CHX) compared to those of conventional GP points. METHODS: Standardized root canals were prepared in 192 bovine incisors. The canals were sterilized and then inoculated with one of two bacterial species (n=96 teeth per bacterium). After anaerobic incubation at 37°C, the inoculum was removed and the canals were filled with one of the three points. Control teeth were filled with a saline/serum mixture. After 0, 1, 4 and 8 days of anaerobic incubation, the numbers of viable bacteria (CFU/ml) were determined on both the points and the canal wall dentin. Six replicates were carried out for each experiment. RESULTS: None of the points completely eradicated the bacteria in the canal. GP+CHX was significantly more effective than GP+Ca(OH)(2) and GP (P<.05 in each case). The inhibitory effect of GP+Ca(OH)(2) did not significantly differ from that of GP (P>.05). Compared to the controls, the antibacterial effect of the medicated points was reached initially. CONCLUSION: Within the limitations of the in vitro model, the incorporation of commonly used medicaments in GP does not offer a long-lasting antibacterial advantage over non-medicated GP.

Effectiveness of the bond established between ceramic inlays and dentin using different luting protocols.

PURPOSE: To evaluate the ceramic-to-dentin bond following luting with light- and dual-curing resin composites using different adhesive techniques. MATERIALS AND METHODS: Dentin surfaces from 160 human molars were ground flat and randomly divided into eight groups (n = 20). Vita Mark II ceramic disks measuring 2 and 4 mm in thickness were bonded to the dentin with one of the following luting systems: Syntac/Tetric Ceram (ST), Syntac/Variolink II (SV), OptiBond Solo Plus/ Prodigy (OP), OptiBond Solo Plus/Nexus 2 (ON). Two different irradiation times (60 s, 120 s) were used per luting system, each without (-PC) and with (+PC) precuring the respective adhesive layer. After storage in water for 24 h at 37°C, the bonded specimens were sectioned perpendicularly to the adhesive interface into 1-mm-thick sticks. Three sticks per specimen were loaded to failure under tension in the Zwicki 1120. Failure analysis was performed using a scanning electron microscope (SEM). RESULTS: Four-way ANOVA showed that the ceramic thickness, the type of luting system used, and the adhesive precuring had a significant effect on the microtensile bond strength. The longer irradiation times did not significantly increase the bond strength. The highest values were recorded with SV/+PC (27.9 ± 4.3 MPa) and the lowest with ST/-PC (10.2 ± 3.5 MPa). Under the SEM, failed specimens that had not been precured showed significantly more exposed dentin than those which had been precured (chi-square test). CONCLUSION: The precuring step of light-curing bonding systems and the use of dual-curing luting composites were shown to optimize the dentin bond under thick ceramic layers.

Effects of self-curing activator and curing protocol on the bond strength of composite core buildups.

PURPOSE: To determine the effect of the polymerization mode of simplified bonding systems and the corresponding core buildup resin composite on the bond strength to dentin. MATERIALS AND METHODS: Composite core buildups were bonded to flat prepared dentin surfaces of 320 human molars using a two-step etch-and-rinse (Excite, ER) and a two-step self-etching (AdheSE, SE) bonding system. Bonding systems were used both with and without their respective self-curing activators (Excite DSC, ER+SC; AdheSE DC, SE+SC). Six curing protocols for the dual-curing composite (MultiCore Flow) were examined: self-curing for 5 min (a); irradiation with light from each aspect for 10 s (b), 20 s (c), and 40 s (d); and irradiation with light from the occlusal aspect only for 60 s (e) and 120 s (f). Shear bond strengths were measured immediately after curing. Additional measurements were performed after water storage of the specimens for 24 h at 37°C. These specimens had been cured according the curing protocols given in the manufacturer's instructions (groups a and d). Failure modes were analyzed using scanning electron microscopy. RESULTS: Immediate bond strengths were significantly different among the bonding systems (p < 0.001): SE > ER > ER+SC > SE+SC. Immediate bond strengths of ER and SE were significantly lower when the composite was self-cured (p < 0.05). The use of SC activators reduced the bond strength and promoted adhesive failures to dentin. A severe incompatibility problem was observed between the composite and SE+SC. CONCLUSION: Dentin bonding of dual-curing composite core buildups in combination with simplified bonding systems is still unsatisfactory, even when SC activators are employed. For adequate bonding to dentin, polymerization of the dual-curing composite should always be light initiated.

Feasibility of ultra-short echo time (UTE) magnetic resonance imaging for identification of carious lesions.

The objective of this study was to investigate the potential of ultra short echo time imaging for the assessment of caries lesions and early demineralization. 12 patients with suspected caries lesions underwent a dental magnetic resonance imaging investigation comprising ultra short echo time imaging (echo time=50 µs) and spin echo imaging. Before the dental magnetic resonance imaging, all patients underwent a conventional clinical dental investigation including visual assessment of the teeth as well as dental x-ray imaging. All lesions identifiable in the x-ray could be clearly identified in the ultra short echo time images, but only about 19% of the lesions were visible in the spin echo images. In 19% of all lesions, the lesions could be more clearly delineated in the ultra short echo time images than in the x-ray images. This was especially the case for secondary lesions. In direct comparison with the x-ray images, all lesions appeared substantially larger in the dental magnetic resonance imaging data. The presented data provide evidence that caries lesions can be identified in ultra short echo time magnetic resonance imaging with high sensitivity. The apparent larger volume of the lesions in dental magnetic resonance imaging may be attributed to fluid accumulation in demineralized areas without substantial breakdown of mineral structures.

Antibacterial activity of a triclosan-containing resin composite matrix against three common oral bacteria.

This study investigated the antibacterial effect of a resin composite matrix with or without incorporated triclosan (0.3 wt%) on Streptococcus mutans, Actinomyces viscosus and Lactobacillus casei. In the quantitative assay, bacterial suspensions were filled into 20-µl cavities within temporary restorative resins. After 0, 4, 8, 12, 24 and 48 h of incubation, the suspensions were removed from the restoratives and the numbers of viable bacteria were determined. Bacterial suspensions incubated without restoratives served as the controls. Ten replicates were carried out for each experiment. The resin composite containing triclosan demonstrated variable degrees of antibacterial activity against the microorganisms, revealing a significant inhibitory effect on S. mutans within 12 h compared to the control. The viable counts of A. viscosus significantly decreased after 24 h. A significant reduction of L. casei was observed after 48 h. The unloaded resin composite did not reveal a marked antibacterial effect. The resin composite loaded with triclosan might be beneficial in preventing cavity contamination and minimizing the risk of pulpal irritation in the short-term.

Effectiveness of bonding fiber posts to root canals and composite core build-ups.

This study investigated the effects of fiber posts, silanization, and luting agents on the interfacial strength to root dentin and composite cores. Root canals of 120 crownless human teeth were instrumented. Three different posts (opaque and translucent), with and without silane treatment, were bonded using etch-and-rinse, self-etch, and self-adhesive luting agents. The restored roots were built up with dual-curing composite. After storage in water for 24 h at 37 degrees C, 2-mm-thick slices were cut from each sample: one from the composite core and one from the restored root. Interfacial push-out bond strengths of the posts were determined in a universal testing machine. Failure modes were analyzed using scanning electron microscopy. The post type and the luting agent had significant effects on both the post-to-dentin and post-to-core strengths. Silanization did not significantly influence post-to-dentin strengths, but enhanced post-to-core strengths. With etch-and-rinse luting agents, debonding occurred predominantly between the post and the cement, while the self-etch and self-adhesive luting agents showed more failures on root dentin. No failures occurred between the composite core and the cement. The combination of translucent posts and etch-and-rinse dual-curing luting agents can positively influence the retention of fiber posts in root canals. Silanization seems to be less relevant for intra-root canal bonding, but may have beneficial effects on post-to-core strengths.

Effect of different surface treatments on the composite-composite repair bond strength.

The aim of this study was to investigate the effect of different mechanical and adhesive treatments on the bond strength between pre-existing composite and repair composite using two aging times of the composite to be repaired. Standardized cylinders were made of a microhybrid composite (Spectrum TPH) and stored in saline at 37 degrees C for 24 h (n = 140) or 6 months (n = 140). Three types of mechanical roughening were selected: diamond-coated bur followed by phosphoric acid etching, mini sandblaster with 50-microm aluminum oxide powder, and 30-microm silica-coated aluminum oxide powder (CoJet Sand), respectively. Adhesive treatment was performed with the components of a multi-step bonding system (OptiBond FL) or with a one-bottle primer-adhesive (Excite). In the CoJet Sand group, the effect of a silane coupling agent (Monobond-S) was also investigated. The repair composite (Spectrum TPH) was applied into a mould in three layers of 1 mm, each separately light-cured for 40 s. Repair tensile bond strengths were determined after 24-h storage. Mechanical and adhesive treatment had significant effects on repair bond strength (P < 0.001). The age of the pre-existing composite had no significant effect (P = 0.955). With one exception (CoJet Sand/OptiBond FL Adhesive), adhesive treatments significantly increased repair bond strengths to 6-month-old composite when compared to the controls without adhesive. Adhesive treatment of the mechanically roughened composite is essential for achieving acceptable repair bond strengths. The more complicated use of silica-coated particles for sandblasting followed by a silane coupling agent had no advantage over common bonding systems.

Marginal integrity of class V restorations: SEM versus dye penetration.

OBJECTIVES: To perform an in vitro investigation on the marginal integrity of different adhesives (Optibond FL, Scotchbond 1XT, Clearfil SE Bond, Adper Prompt L-Pop, S(3) Bond, iBond exp., Adper Prompt L-Pop) in combination with Tetric Ceram as well as an experimental silorane-restorative (Hermes, Hermes Bond; 3M ESPE) using SEM and dye penetration (2% methylene blue) in a comparative manner. METHODS: Standardized class V-cavities (3 mm x 1.5 mm) were prepared in 70 extracted human teeth (n=10). The adhesives were applied according to manufacturers' instructions. The cavities were restored with three increments. After finishing and polishing (Sof-Lex discs) and thermocycling (5000x, 5/55 degrees C), replicas were taken and the teeth immersed in the dye for 10s (D10) and evaluated. After another penetration of 30 min (D30) a final evaluation of the percentage of dye-penetrated margins was conducted. RESULTS: The median percentages in marginal gaps (%) at the enamel margins for the three methods investigated (D10/D30/SEM) were--Optibond FL: 0/0/4, Scotchbond 1 XT: 5/16/11, Clearfil SE Bond: 0/0/0, S(3) Bond: 0/0/1, iBond exp.: 20/42/12, Adper Prompt L-Pop: 5/23/8, Hermes/Hermes Bond: 5/45/24. Cementum margins--Optibond FL: 0/1/0, Scotchbond 1 XT: 0/21/23, Clearfil SE Bond: 0/0/4, S(3) Bond: 0/0/0, iBond exp.: 0/0/0, Adper Prompt L-Pop: 10/32/23, Hermes/Hermes Bond: 0/0/13. After pooling the data of all groups, a Spearmann's rho test showed a good correlation between the methods D10 and D30 at the enamel margins and at the entire cavity margins (correlation coefficient 0.8 and 0.7). SIGNIFICANCE: SEM did not correlate with the results obtained from D10 (correlation coefficient <0.5). A fair correlation was found between SEM and D30 for the entire cavity margin but a good correlation for the enamel margins. No correlation between investigation methods was determined at the cementum margins. D30 showed a better correlation to SEM than D10 did. Therefore, 30 min of dye penetration time seems to be more suitable than 10 s.

Dentin diffusion of HEMA released from etch-and-rinse and self-etch bonding systems.

The aim of this in vitro study was to determine the diffusion of 2-hydroxyethyl methacrylate (HEMA) released from different bonding systems (BS) through dentin. Occlusal cavities with a remaining dentin thickness (RDT) of 0.5 mm (n=90) and 0.25 mm (n=80), respectively, were prepared in dentin discs of non-carious human molars. Artificial pulp chambers were attached to the pulpal side of each dentin disc. Bonding systems were applied with (Clearfil SE Bond, OptiBond FL, OptiBond Solo Plus) or without (AdheSE, Adper Prompt L-Pop, Clearfil SE Bond, OptiBond FL, OptiBond Solo Plus Self Etch, Xeno III) prior phosphoric acid etching. HEMA was detected by gas chromatography/mass spectrometry (n=10 per BS and RDT). The highest mean HEMA concentration was found in the 0.25 mm RDT group treated with OptiBond FL (13.3 microg) and the lowest mean HEMA concentration was detected in the 0.5 mm RDT group treated with AdheSE (0.5 microg). At 0.25 mm RDT the quantities of HEMA recovered in the artificial pulp chambers were significantly higher than at 0.5 mm RDT, except for Clearfil SE Bond. Etching with phosphoric acid increased the detected HEMA quantities compared with self-etch BS. In deep cavity preparations, etching with phosphoric acid should be avoided in favor of the use of self-etch BS.

Dentin bonding of light- and self-curing resin composites using simplified total- and self-etch adhesives.

OBJECTIVE: The purpose of this study was to evaluate the influence of (1) the curing mode of resin composites and (2) activators for dual curing of the bonding on dentin bond strength. METHODS: The light-curing resin composite Brilliant (B) and the self-curing resin composite Brilliant MH were bonded with the following adhesives (n = 10): OptiBond FL, Excite, Prime&Bond NT, OptiBond Solo Plus, Adper Prompt L-Pop, Clearfil SE Bond, Xeno III, and AdheSE. Excite, Prime&Bond NT, and OptiBond Solo Plus were also used in combination with activators for dual curing. Tensile bond strengths were measured after 24 hours of water storage (37 degrees C), and fractured surfaces were analyzed in the scanning electron microscope. RESULTS: Except for Excite/dual curing and Prime&Bond NT/dual curing, bond strengths with Brilliant MH were significantly lower than with Brilliant. Activators significantly increased bond strengths in Excite/Brilliant MH, but not in Prime&Bond NT/Brilliant MH and OptiBond Solo/Brilliant MH. CONCLUSIONS: This study confirms the incompatibility between self-curing resin composites and simplified bonding systems containing acidic components. Activators for dual-curing the bonding eliminated this chemical incompatibility only in 2 of 3 bonding systems. The use of these activators in combination with light-curing resin composites must be avoided.

Effect of simulated pulpal pressure on dentin bond strength of self-etching bonding systems.

PURPOSE: To evaluate in vitro the influence of dentin perfusion on dentin bond strengths of etch and rinse and self-etch adhesives. METHODS: 64 extracted human molars were ground flat and resin composite (Brilliant) was bonded using the following bonding systems (each n=16): OptiBond FL including phosphoric acid etching (OFL+), OptiBond FL without phosphoric acid etching (OFL-), Clearfil SE-Bond (CSE) and Prompt L-Pop (LP). In each bonding system, half of the specimens (n=8) were bonded without (PP-) and half with (PP+) simulated intrapulpal pressure. After water storage (37 degrees C, 24 hours), a 1 mm thick slice was cut vertically from the middle of each sample. Microtensile bond strength (microTBS) was determined and the debonded surfaces were investigated in SEM for the mode of failure. Statistical significance was determined by ANOVA, Tukey-test, and t-test (P= 0.05). RESULTS: Mean microTBS measured were (MPa +/- SD): OFL+/PP- 58.6 (5.8), OFL+/PP+ 38.1 (3.8), OFL-/PP- 37.9 (3.7), OFL-/PP+ 33.3 (3.5), CSE/PP- 41.1 (4.1), CSE/PP+ 39.0 (4.4), LP/PP- 35.8 (6.4), LP/PP+ 29.0 (4.8). The presence of PP resulted in a decrease of microTBS in all bonding systems, which reached significance in OFL+ (P< 0.0001), OFL- (P= 0.023) and LP (P= 0.032). Both, with and without PP, the bonding systems showed significant differences in bond strength (ANOVA: P< 0.0001).

Coverage of Miller class I and II recession defects using enamel matrix proteins versus coronally advanced flap technique: a 2-year report.

BACKGROUND: The aim of this study was to evaluate a comparison of the coronally advanced flap procedure with or without the use of enamel matrix proteins in the treatment of recession defects. METHODS: This 2-year study was conducted as a blinded, split-mouth, placebo-controlled, and randomized design. Thirty patients from two dental schools with two paired buccal recession defects were chosen. Surgical recession coverage was performed as the coronally advanced flap technique. One site was additionally treated with derivative (EMD) and the other site with a placebo (propylene glycol alginate [PGA]). A blinded examiner assessed pre- and post-surgical measurements. Measurements comprised the height and width of the gingival recession, height of keratinized tissue, probing attachment level, probing depth, and alveolar bone level. RESULTS: Twenty-four months after therapy, both treatment modalities showed significant root coverage and probing attachment gain. The mean gingival recession decreased from 3.6 to 0.8 mm for the EMD-treated sites and from 3.8 to 1.4 mm for the control sites. However, this difference was not statistically significant (P = 0.122). Similarly, all other clinical parameters did not differ significantly in the between-group comparison except for the recession width (P = 0.027) and probing depth (P = 0.046) exhibiting higher reductions in the EMD group. Complete root coverage could be maintained over 2 years in 53% of the EMD versus merely 23% in the control group. A total of 47% of the treated recessions in the control group deteriorated again in the second year after therapy compared to 22% in the EMD group. CONCLUSION: Enamel matrix derivative seems to provide better long-term results.

In vitro comparison of dentin bonding systems: effect of testing method and operator.

OBJECTIVES: The purpose of this study was to investigate the influence of different in vitro tests on the ranking of four dentin bonding systems (OptiBond FL, Solid bond, OptiBond Solo, Etch&Prime 3.0) and to determine operator influence on push-out test results. METHOD AND MATERIALS: One-hundred eighty extracted human molars were used in this study. For all bonding systems, bond strengths were determined using the shear, tensile, and push-out tests. In the push-out test, two series of specimens were bonded by two operators. Additionally, margin adaptation in Class V cavities was evaluated using scanning electron microscopy and dye penetration. RESULTS: Both test methods and bonding systems revealed a significant influence on bond strength. Ranking of mean bond strengths was identical in the shear and tensile tests but different in the push-out test. In addition, material ranking in the push-out test was found to be operator dependent. No correlation was observed between bond strength and margin adaptation. A weak correlation was found between the percentage of gap formation and dye penetration in Class V cavities. CONCLUSION: Comparisons of dentin bonding systems based on the results of different in vitro tests may be misleading. Operator influence on the results of push-out tests require further consideration.

Marginal adaptation of dentin bonded ceramic inlays: effects of bonding systems and luting resin composites.

This in vitro study evaluated the marginal adaptation of bonded inlays of lucite-reinforced glass ceramic (Empress) to dentin as influenced by different bonding systems and by luting resin composites (LRCs) with different curing modes. Forty-eight Empress inlays etched with 5% hydrofluoric acid and treated with a silane-coupling agent (Monobond-S) were bonded to two-surface Class II cavities. Two total-etch bonding systems (OptiBond FL, Nexus) and one bonding system with selective enamel etching and a self-conditioning dentin primer (ART Bond) were included in the study. ART Bond was tested with and without the pre-curing of a first layer of adhesive resin selectively applied to the cervical cavity floor (selective double-bond technique). Each bonding system was used in combination with a light-cured resin composite (Prodigy) and a dual-cured LRC (Nexus or Vita Cerec Duo Cement). Marginal integrity was evaluated before and after thermocycling (TC) in a scanning electron microscope (SEM). Dye penetration tests were performed after TC was completed. The median percentages of continuous margin in dentin ranged from 80% to 100% before TC and from 53.5% to 96.1 % after TC. After TC, the influence of the bonding system was more pronounced than that of the LRC. In combination with the LC resin composite, ART Bond with precuring was significantly higher and the Nexus bonding system had significantly lower proportions of continuous margin than all the other bonding systems investigated. Swelling of the adhesive along the gingival margins was frequently found with the Nexus bonding system and with ART Bond without pre-curing. Microleakage was detected with all bonding system/LRC combinations, with somewhat lower rates in specimens completed using the selective double-bond technique. With the exception of the Nexus bonding system, post-TC marginal integrity was not influenced by the curing mode of the LRC (LC vs DC). In conclusion, the marginal quality of dentin bonded ceramic inlays can be improved by proper selection of the bonding sys- tem/LRC combination. The results of this study indicate the use of the Nexus luting system as directed without substitution.

Additive antimicrobial activity of calcium hydroxide and chlorhexidine on common endodontic bacterial pathogens.

It is an established procedure to use calcium hydroxide [Ca(OH)2] as a therapeutic component to achieve sterilization of infected root canals. Unfortunately, some bacterial species are relatively resistant to Ca(OH)2 and are therefore associated with treatment failures. The objective of this study was to identify combinations of substances that improve antimicrobial activity. Ca(OH)2 was used as a suspension or as a component of gutta-percha points. Efficacy of killing was compared for (a) Ca(OH)2 suspension alone; (b) zinc oxide (ZnO) points alone; (c) Ca(OH)2 suspension combined with ZnO points; (d) Ca(OH)2 suspension combined with ZnO/chlorhexidine points; and (e) Ca(OH)2 points combined with ZnO/chlorhexidine points. Common endodontopathogenic bacterial species (Enterococcus faecalis, Fusobacterium nucleatum, Peptostreptococcus micros, Porphyromonas gingivalis, Streptococcus intermedius) in pure cultures served as target organisms. In the in vitro assay, the antibacterial substances and approximately 10(7) colony forming units of test bacteria were co-incubated in diluted human serum under growth conditions appropriate for the single bacterial species. Samples were taken on days 0, 1, 2, 4, 7, and 14 of incubation and viable counts determined. Gram-negative bacteria were sufficiently killed by Ca(OH)2 alone. Combinations with other agents did not improve the killing kinetics. For the inactivation of the Gram-positive bacteria P. micros and S. intermedius, a combination of Ca(OH)2 and ZnO/chlorhexidine, killed the bacteria faster than Ca(OH)2 alone. For E. faecalis, combining Ca(OH)2 suspension with ZnO/chlorhexidine points lead to a faster decrease in the overall number of viable bacteria, but no test conditions lead to the complete loss of culture viability. The results of this study support the use of a combination of Ca(OH)2 and chlorhexidine for faster eradication of P. micros and S. intermedius from infected root canals.