Abstract: Secondary caries, marginal discoloration and marginal gap/fracture account for a significant majority of clinical diagnoses of restoration failure and reason for restoration replacement. These failures occur at the interface between the restoration and the cavity preparation. It is an underlying belief, or at least an underlying assumption of the dental profession, that improving the seal between a restorative material and tooth structure will reduce the frequency of such occurrences, which will in turn lead to enhanced restoration longevity. This paper reviews the current status of in vitro literature regarding the ability of modern restorative materials and techniques to reliably seal cavity preparations. In addition, methodology for accomplishing in vitro research is reviewed for the purpose of elucidating trends, areas of interest and controversial topics.

Abstract: PURPOSE To evaluate the micro-shear bond strength of current adhesive systems to cervical and mid-coronal enamel. MATERIALS AND METHODS Two commercially available resin adhesives were investigated; a self-etching primer system (Clearfil SE Bond) and a one-bottle adhesive system (Single Bond) intended for use with the total-etch wet-bonding technique were employed. Two regions of enamel, cervical and mid-coronal regions, were chosen from the buccal surface of extracted molars and were then bonded with each adhesive system and submitted to the micro-shear bond test. In addition, the conditioned enamel surfaces without any bond and the enamel-resin adhesive interfaces were studied morphologically using scanning electron microscopy (SEM). RESULTS No significant differences were found between the adhesive systems used (P > 0.05). However, for both bonding systems, cervical enamel showed significantly lower bonding than mid-coronal enamel (P < 0.05). The relatively lower bond strengths obtained from cervical enamel probably resulted from its aprismatic structure, which appears to be more resistant to dissolving in acids than prismatic mid-coronal enamel.

Abstract: PURPOSE To determine the effect of self-etching primer application method on enamel bond strength. MATERIALS AND METHODS Five commercial self-etching primer systems, Imperva Fluoro Bond, Mac Bond II, Clearfil Liner Bond II sigma, Clearfil SE Bond and Unifil Bond were used. Bovine mandibular incisors were mounted in self-curing resin and the facial enamel surfaces were ground wet on 600-grit SiC paper. The self-etching primers were only applied without agitation (inactive) or were agitated by brush (active); and resin-based composites were condensed into the mold (o4 x 2 mm) on the enamel surface and light cured. Fifteen specimens per test group were stored in 37 degrees C water for 24 hours, or followed by thermal cycling, and shear tested at a crosshead speed of 1.0 mm/minute. One-way ANOVA followed by the Student's t-test or Duncan multiple range test were used. RESULTS The bond strengths with active application were higher than with inactive application. Significant differences were found for Fluoro Bond, Mac Bond II, and Unifil Bond. From the results of this study, active application of self-etching primer may help to ensure the creation of roughened enamel surface and enhance the penetration of primer into subsurface demineralized enamel.

Abstract: PURPOSE To compare the effectiveness of rinsing with an essential oil-containing antimicrobial mouthrinse with that of dental floss in reducing interproximal gingivitis and plaque in an unsupervised 6-month clinical trial designed in accordance with ADA Acceptance Program Guidelines. MATERIALS AND METHODS 319 qualifying subjects, aged 18-63, were randomized into one of three groups: essential oil mouthrinse (Listerine Antiseptic); dental floss (Reach Dental Floss); or a negative control rinse. At baseline, subjects received a complete oral soft tissue examination and scoring of the Modified Gingival Index (MGI), modified Quigley-Hein Plaque Index (PI), and bleeding index (BI). Following a complete dental prophylaxis and receiving flossing or rinsing instructions, subjects started on their respective regimen. They continued on their assigned regimen unsupervised at home, in addition to toothbrushing, and were reexamined at 3 and 6 months. The treatment groups were compared with respect to baseline demographic and clinical variables. The primary efficacy variables were mean interproximal MGI and PI at 6 months. Intergroup differences at 3 and 6 months were tested using a one-way analysis of covariance model with treatment as a factor and the respective baseline value as the covariate. In addition, the essential oil mouthrinse was compared to floss for interproximal gingivitis reduction using "at least as good as" statistical criteria. RESULTS 301 subjects were considered evaluable. There were no statistically significant differences among the 3 groups at baseline, with the exception of the essential oil mouthrinse group having significantly fewer AfroAmerican subjects than the other two groups. For the interproximal MGI, the essential oil mouthrinse and flossing were both significantly more effective than the negative control (P < 0.001) at 3 and 6 months. The essential oil mouthrinse was shown to be "at least as good as" dental floss for the control of interproximal gingivitis. For the interproximal PI, the essential oil mouthrinse was significantly more effective than the negative control at 3 and 6 months (P < 0.001) while flossing was significantly more effective than the negative control at 3 months (P < 0.05) but not at 6 months. The essential oil mouthrinse was significantly more effective than floss (P < 0.001) at both these time periods.

Abstract: PURPOSE: To compare pain response between two different flow rates (slow versus fast) of local anesthetic solution injected into palatal tissue using the recently available Wand Local Anesthetic System (WLAS), which provides the technologic advance to permit reliable replication of constant injection flow rates, regardless of tissue resistance. METHODS AND MATERIALS: Twenty adult subjects received bilateral palatal injections of local anesthetic in random sequence during the same appointment following topical anesthesia application. Pain response was measured by subjective self-report using a visual analogue scale, a quantified verbal descriptor scale, and a comparison to prior injection experience, as well as an operator's global assessment of the subject's pain response. Heart rate, as a physiologic indicator of pain response, was also recorded. RESULTS: All measurements of pain response were statistically less for the slow compared to the fast injection rate. No significant difference in mean heart rate, however, was demonstrated between the two flow rates. A slow, constant flow rate (161 sec/mL) of a 0.3 mL volume of local anesthetic solution was statistically less painful than a fast flow rate (29 sec/mL) during palatal injection. Contrary to the manufacturer's claim, the WLAS reduced but did not eliminate pain elicited by palatal injections in some patients.

Abstract: PURPOSE To evaluate clinically whether the addition of glutardialdehyde to the one-bottle enamel-dentin adhesive Gluma Comfort Bond (GCB) has a desensitizing function, as insinuated by the brand name Gluma Comfort Bond+Desensitizer (GCB+D). MATERIALS AND METHODS Two pain studies following identical protocols were conducted in Abu Dhabi (A) and Bologna (B). Each of the 60 and 59 patients selected, respectively, had two sensitive cervical tooth sites, characterized by a score three or higher on a five-step pain scale: 1 (no), 2 (slight), 3 (mild), 4 (severe), 5 (very severe) discomfort upon application of a 2-second cold air stimulus. The buccal sensitive sites treated in A were generally small, in B larger and in most cases extending into the proximal tooth area. The patients indicated their discomfort level according to the pain scale prior to and immediately after topical application of GCB and GCB+D, respectively, and then at recalls after 1 week, 1 (A) or 3 (B) months, and 6 months. The data was statistically analyzed by chi2-tests (P < 0.05). RESULTS With the cumulative scores 1 and 2, the following percentage success rates were found for GCB/GCB+D. A: postoperatively 93/98, 1 week and 1 month 98/98, and at 6 months 92/100. In B, the respective decrease in sensitivity was uniformly 43/100 throughout the entire evaluation period, postoperatively through 6 months. The 33 teeth (57%) of GCB with scores 3 and 4 in the B-study received a rescue treatment with Gluma Desensitizer immediately after the 1 week recall. This regimen reduced the sensitivity instantaneously to scores 1 and 2 until the end of the evaluation after 6 months. In the A-study, GCB+D was significantly more effective than GCB after 1 week, 1 month, and 6 months, in the B-study at all recall sessions. It is hypothesized that a thin film of adhesive applied to a sensitive area may not polymerize and seal the dentin surface adequately due to oxygen inhibition. In particular, proximal sensitive tooth sites with poor access for adhesive application are suspected to remain inadequately sealed with a polymer film and thus sensitive. In this latter case however, glutardialdehyde as a component of the adhesive compound will result in coagulation of peripheral tubular liquid protein and thus desensitization, due to hampering of the liquid shift across the tubules upon excitation of a cold stimulus. In conclusion, glutardialdehyde played an active and effective role as a desensitizing agent, when added to the ethanol-water based one-bottle adhesive Gluma Comfort Bond.

Abstract: PURPOSE To clinically evaluate conservative fiber-reinforced composite inlay fixed partial dentures (IFPDs) bonded to inlay abutments. MATERIALS AND METHODS Forty fiber-reinforced composite IFPDs were made for 29 patients. Restorations were manufactured with the composite Targis reinforced by Vectris prefabricated glass-fiber elements and were inserted with a high viscosity insertion technique. Forty bonded IFPDs were examined clinically after 1 year, and 25 after 2 years, using modified USPHS criteria. Twenty-five abutment inlays and 12 pontics were analyzed quantitatively by scanning electron microscopy SEM. Results were tested for statistical significance with ANOVA. RESULTS Although most clinical criteria were rated "alpha", four IFPDs had to be replaced: two retainers debonded and two presented total delamination of veneering material from fiber framework. Two partial delaminations were repaired intraorally. No fractures of framework were observed. SEM marginal analysis of tooth-composite interface exhibited 96.5 +/- 3.0% continuous margin at baseline, 91.0 +/- 5.7% at the 1-year and 89.6 +/- 5.2% at the 2-year recall. Decrease of marginal quality was statistically significant between baseline and 1 year (P= 0.001), but not between 1- and 2-year recalls.

Abstract: PURPOSE To evaluate the 1-year clinical retention rate of restorations of non-carious cervical lesions placed using a "one-bottle" adhesive (One-Step) and one of two low modulus resin-based composite (RBC) restorative materials (AEliteflo or Bisco Glaze) or a microfilled RBC (Silux Plus). MATERIALS AND METHODS 105 non-carious cervical lesions in 14 patients, mean age 60 years, were restored using either AEliteflo, Bisco Glaze or Silux Plus with One-Step dentin bonding agent. The dentin surface was lightly roughened with a fine diamond stone, cleaned with pumice and water and restored according to the manufacturers' instructions. Patients were recalled at 6 months and 1 year, and the restoration sites examined. RESULTS At 6 months all restorations were present. At 1 year, five restorations were missing (two Silux, three AEliteflo), three of which were in one patient. A cumulative retention rate of 95% was recorded. A small number of restorations exhibited marginal discoloration, but this was believed to be due to excess RBC on unetched enamel.

Abstract: PURPOSE To compare the long-term caries increment associated with the use of two dentifrices: (1) a test dentifrice containing 0.836% sodium monofluorophosphate (1100 ppm F) in a dicalcium phosphate dihydrate base plus 10% xylitol; and (2) a positive control dentifrice containing 0.836% sodium monofluorophosphate (1100 ppm F) in a dicalcium phosphate dihydrate base. MATERIALS AND METHODS Three thousand three hundred ninety four (3,394) school children aged 7-12 years were selected to participate in this double blind clinical caries study at 28 public schools in the central plateau of Costa Rica. Children accepted for participation were stratified into two balanced groups within the participating schools on the basis of age and sex, and assigned to one of the two dentifrices. The study was conducted in harmony with the guidelines for caries clinical studies published in 1988 by the Council on Dental Therapeutics of the American Dental Association, and employed clinical diagnostic criteria provided in 1991 guidelines published by the National Institute of Dental Research (NIH/NIDR). Dental radiographs were not employed. RESULTS Of those subjects who met the initial inclusion/exclusion criteria for this study, 2,539 were available for the 30-month exam. DFS increments over the 30-month period of this clinical study were 1.30 for the test dentifrice containing 10% xylitol, and 1.51 for the positive control dentifrice without xylitol; for DFT, the corresponding increments were 0.69 for the test dentifrice containing 10% xylitol, and 0.81 for that which did not contain xylitol. For both DFS and DFT, the increments associated with the test dentifrice containing 10% xylitol were statistically significantly lower than those associated with the positive dentifrice without xylitol (P < 0.05), with the observed reductions in caries increment exceeding 10% in for both parameters.

Abstract: Purpose To evaluate the effect of enamel prism orientation on microtensile bond strengths (MTBS) to enamel using two current bonding systems. Materials and methods The crown segments of extracted human third molars were cut mesio-distally to obtain buccal and lingual halves. One of the halves was cut horizontally at the middle of the crown to make a flat enamel surface parallel to prism orientation (parallel specimen). The other half was ground at the equator of the crown to produce a flat enamel surface perpendicular to the prism orientation (perpendicular specimen). Each surface was ground with 600 grit silicone carbide paper, treated with Clearfil Liner Bond IIsigma (LB) or Single Bond (SB) according to the manufacturers' instructions and resin composite, AP-X or Z100, respectively, was built up onto it. After storage in water at 37 degrees C for 24 hours, all bonded specimens were sectioned and trimmed for measuring MTBS. In MTBS, the parallel specimens were stressed perpendicular to the prism long axis and the perpendicular specimens were stressed parallel to the prism axis. Results MTBS of specimens stressed perpendicular to the prism long axis were 11.93 +/- 5.56 MPa for LB and 10.97 +/- 1.80 MPa for SB. MTBS of specimens stressed parallel to the prism axis in LB and SB were 19.07 +/- 6.35 MPa and 23.99 +/- 9.20 MPa, respectively. For each prism orientation, no difference in MTBS was found between the bonding systems (P> 0.05). Both systems showed lower MTBS in specimens stressed perpendicular to the prism long axis than in specimens stressed parallel to the prism axis.

Abstract: The sealing ability of restorations is an important factor in order to prevent or reduce marginal gaps, which are often associated with postoperative sensitivity, caries and pulp disease. Usually the sealing ability of a new material is tested under laboratory conditions before being introduced on the market. However, in vitro evaluation of marginal integrity cannot predict in vivo performances of enamel-dentin bonding systems. A critical review of available data on sealing ability of last generation of adhesive-restorative materials placed on vital teeth is presented. The review includes the data of sealing performances of direct and indirect restorations, ethical considerations, influence of dental substrates on bonding, correlation between in vivo leakage studies and bond strength tests and microscopic evaluations. An in vivo protocol is presented in order to standardize leakage studies performed on vital teeth. A larger number of in vivo leakage tests are desirable in order to compare properties of new materials in multicenter studies. The ideal sequence of evaluation for new enamel-dentin bonding systems should be: in vitro tests, short term in vivo evaluations and then clinical trials.

Abstract: PURPOSE To determine and compare the intrinsic antibacterial activity of commercially available simplified adhesive systems. MATERIALS AND METHODS The antibacterial activity of five self-etching/priming one-step adhesives and three priming/bonding adhesives against Streptococcus mutans, Lactobacillus casei, and Actinomyces viscosus was assessed by the agar disc-diffusion test and determination of the minimum inhibitory/bactericidal concentration (MIC/MBC). Twenty microl of each adhesive was impregnated into a paper disc and placed on an agar plate inoculated with a bacterial suspension, with or without light-irradiation. The size of inhibition zones produced around the specimens was measured after 48 hours of incubation. The MIC values were measured by serial microdilution assays, visually examining the growth of bacteria after incubation with each adhesive for 24-48 hours. The subcultures were made on BHI agar plates from the wells showing no visible growth of bacteria, and the MBC values were determined based on production of colonies. Two primers in two-step self-etching systems and an experimental primer containing chlorhexidine were tested for reference. The results of disc-diffusion tests were analyzed by ANOVA and Fisher's PLSD test. RESULTS The size of inhibition zones produced by adhesives varied among the brands. None of the available commercial adhesives showed significant inhibition against all three of the bacterial species tested. Light-irradiation reduced the size of inhibition zones for a few materials, but a similar trend to the effectiveness of non-irradiated specimens was observed. The antibacterial activity of commercial products determined in terms of MIC/MBC values were different from the results by disc-diffusion tests. The self-etching adhesives with low pH were not necessarily more effective than priming/bonding solutions, and no significant relationships between the acidity and antibacterial effects were found. Compared with commercial products, an experimental primer containing chlorhexidine produced significantly larger inhibition zones against all species (P < 0.05) and exhibited greater bacteriostatic/bactericidal activity, demonstrating lower MIC/MBC values.

Abstract: PURPOSE: To develop an interproximal laboratory model to compare the potential effectiveness of powered brushing to remove biofilm plaque from interproximal spaces beyond the reach of bristles. MATERIALS AND METHODS: Streptococcus mutans biofilms were first grown on glass microscope slides in a drip-flow reactor. The slides were removed and positioned in the interproximal model. Each slide was exposed to 15 seconds powered brushing with either the Sonicare Elite or the Braun Oral-B 3D Excel. The thickness of the biofilm was measured with confocal microscopy at various distances from the bristle tips. RESULTS: The Sonicare Elite reduced the thickness of biofilm by 57% at a distance of 0-5 mm from the bristle tips, 53% at 5-10 mm and 43% at 10-15 mm, relative to biofilm in areas unexposed to brushing. All reductions in thickness were statistically significant (P 0.1).

Abstract: PURPOSE To determine the influence of NaOCl application on shear bond strengths (SBS) to superficial and deep dentin, using Prime & Bond 2.1. MATERIALS AND METHODS Superficial and deep dentin was exposed in 40 extracted third molars by sectioning the occlusal surface immediately under the enamel-dentin junction or close to the pulp chamber. After polishing the dentin disks (600-grit SiC), they were assigned to two groups: (1) 36% orthophosphoric acid for 15 seconds, or (2): 36% orthophosphoric acid for 15 seconds followed by 5% sodium hypochlorite (NaOCl) for 2 minutes. The dentin adhesive was applied as per manufacturer's instructions, followed by TPH resin-based composite. The specimens were stored in water for 24 hours at 37 degrees C and thermocycled x500 and SBS were determined. Data were statistically analyzed with ANOVA and Student's t-test. RESULTS For acid-etched specimens, superficial dentin resulted in statistically higher mean SBS than deep dentin. After NaOCl application, deep and superficial dentin resulted in statistically similar mean SBS. Collagen removal did not affect mean SBS on superficial dentin, while SBS values on deep dentin were increased.

Abstract: PURPOSE Recently, several 'one-bottle' systems have been introduced for bonding into root canals. This study evaluated the influence of two brushes used as carriers of a primer-adhesive solution in the formation of resin tags, adhesive lateral branches and hybrid layer when used to bond fiber posts. MATERIALS AND METHODS Twenty root canal treated teeth, extracted for periodontal reasons, were selected for this study. The samples were randomly divided into two groups of 10 samples each: Group 1: Microbrush + One Step + Dual Link resin cement; Group 2: One Step + Dual Link resin cement. The adhesive system and resin cement were used strictly following manufacturers' instructions. The priming-adhesive solution of the 'one-bottle' system was light-cured before placing the resin cement and the post. Twenty translucent fiber posts were used. Then, root samples were processed for SEM observation. RESULTS The adhesive system showed resin dentin interdiffusion zone (RDIZ), resin tag and adhesive lateral branch formation. Microscopic examination of restored interfaces of Group 1 showed a higher % (P < 0.05) of RDIZ than those found in samples of Group 2. In Group 2 samples RDIZ morphology was well detectable and uniform in the first two thirds of root canals while in the apical third the RDIZ was not uniformly present while in Group 1 RDIZ was visible at the apical third too. No statistically significant differences were found among the two groups coronally and at the middle third, while the apical third of Group 1 showed significantly more resin tags than in Group 2. The characteristic reverse cone shape of resin tags was always noted in the coronal and middle third of the root canals of both groups and at the apical third of Group 1. In the apical third of Group 2 root canals, the resin tags showed a less uniform morphology and a shorter length than those found in the other observed thirds.

Abstract: PURPOSE: To evaluate microleakage at enamel and dentin margins of two composite resins, using bulk and incremental placement techniques, "rebonding", and facial and lingual curing methods. MATERIALS AND METHODS: One hundred standardized Class V cavity preparations were made on the facial surface of extracted human premolars and were randomly assigned to 10 groups. Single Bond was used as the dentin/enamel adhesive. A heavily filled composite resin, Z250, and a microfill, Silux Plus, were inserted and polymerized using five different techniques: (1) incremental placement and facial curing; (2) incremental placement, facial curing and rebonding; (3) bulk placement and facial curing; (4) bulk placement, facial curing and rebonding; (5) incremental placement and lingual and facial curing. After the restorations were finished and polished, the margins of those in the rebonded groups were etched, rinsed, and dried. The adhesive resin, Single Bond, was applied at the composite resin-tooth interface and light-cured. All the specimens were thermocycled, stained with 1% methylene blue, sectioned, and evaluated for leakage (0-4 scale) by two examiners. RESULTS: Almost no leakage occurred at enamel margins. At the cementum margins, differences in microleakage related to restorative material or technique were not statistically significant. However, leakage at the cementum margins was significantly greater than at the enamel margins for both composite resin materials.

Abstract: PURPOSE To compare the whitening effectiveness of two professional vital bleaching systems in a randomized clinical trial. MATERIALS AND METHODS Balancing for baseline color, 6 9 adult volunteers were randomized to either a whitening strip containing 6.5% hydrogen peroxide (Professional Crest Whitestrips) or a custom tray-based system using both hydrogen and carbamide peroxide (Nite White Excel2). Total contact time was 21 hours for the strip system and 28 hours for the 10% carbamide peroxide equivalent tray system. Whitening response was measured objectively as L*a*b* from digital images of the maxillary anterior teeth. RESULTS Both treatments resulted in significant (P < 0.01) improvements in yellowness (deltab*), brightness (deltaL*) and overall color (deltaE*). For between group comparisons, strip subjects had a statistically significant or directionally favorable whitening response relative to the tray system at intermediary time points, while at the end-of-treatment, the strip group had highly statistically significant (P < or = 0.005), superior whitening response for all color parameters measured in the study. Both treatments were generally well tolerated, with 35-40% of the subjects in each group reporting minor tooth sensitivity or gingival irritation.

Abstract: Purpose To evaluate the feasibility of the calcium phosphate precipitation (CPP) method as a treatment for dentin hypersensitivity using vital teeth of beagle dogs. Also, gingival tissue response to two types of CPP methods was examined histologically. Materials and methods Dentin tubules of the dogs' vital teeth were exposed by shallow cavity preparation followed by etching with 50% citric acid to simulate the condition of hypersensitive dentin. After CPP treatment was applied to the vital tooth, the dentin surface and longitudinal sections were observed by SEM to evaluate the occluding ability of the CPP method. The precipitate was also analyzed by energy-dispersive X-ray microanalysis to obtain compositional information. The gingival tissue before and after CPP method was examined histologically with light microscopy. Results Dentin tubules were occluded homogeneously and completely with an apatitic mineral after application of the CPP treatment in vital teeth. However, the depth of the precipitate in dentin tubules from the dentin surface was approximately half that seen in extracted teeth. No histological change was observed in gingival tissues when NaHCO3 was used as a post-treatment solution of the CPP method, whereas another CPP method using NaOH solution resulted in atrophy and degeneration of the epithelium of gingival tissue.

Abstract: PURPOSE To evaluate the clinical response of a low peroxide concentration bleaching system with a desensitizing agent relative to a marketed control. MATERIALS AND METHODS After balancing for baseline color and age, 34 healthy adult volunteers were randomized to one of two marketed bleaching systems, 5% carbamide peroxide bleaching gel + potassium nitrate in a custom tray (Colgate Platinum Gentle Plus) or 6.0% hydrogen peroxide bleaching strips (Crest Whitestrips). Daily contact time was 6-8 hours for the tray system compared to 1 hour for the strip system, following manufacturers' instructions. Whitening was measured objectively using digital image analysis to assess L*a*b* after 7 days, while tolerability was assessed through interview and examination. RESULTS The predominantly female (85%) and non-smoking (91%) study population ranged from 20-47 years of age. Both treatments yielded a statistically significant (P < 0.001) whitening benefit with respect to reduction in yellowness (Ab*) and improvements in other color endpoints (deltaL*, deltaE*, and a new parameter, deltaW*) compared to baseline. The strip group experienced greater color improvement on average for all color parameters in the study. After 7 days treatment, the adjusted mean deltab* was -1.24 in the strip group and -0.65 in the tray group, with these groups differing significantly (P = 0.04). Tooth sensitivity was reported by 13% of subjects using the hydrogen peroxide strips, compared to 22% of subjects using the carbamiide peroxide potassium nitrate tray system. No subjects discontinued treatment early due to an adverse event.

Abstract: PURPOSE To evaluate microleakage at the dentin margins of Class II resin-based composite restorations using four simplified adhesive systems: Etch & Prime 30, Prime & Bond NT, Clearfil Liner Bond 2V and Clearfil SE Bond, upon thermal and mechanical stresses MATERIALS AND METHODS Forty slot preparations (5mm x 3mm x 15mm) were cut in sound human molars with gingival margins below the cement/enamel junction All adhesive systems were applied strictly according to manufacturers' instructions Cavities were restored using Clearfil AP-X composite resin After finishing and polishing, teeth were submitted to thermal (x700, 5-55 degrees C, 60-second dwell time) and consecutively mechanical cycling (100,000 cycle; 8 Kgf load) Specimens were coated with nail polish, immersed in silver nitrate for 2 hours and sectioned longitudinally with a diamond disc The extent of leakage was ranked using a 0-4 scale RESULTS Statistical analysis was performed using Kruskal-Wallis test Minimal leakage occurred with Clearfil SE Bond There was a statistically significant difference (P<001) between this system and Clearfil Liner Bond 2V, although the latter also showed low values of dye penetration No statistically significant difference was found between Etch & Prime 30 and Prime & Bond NT Both showed statistically greater leakage than the two other systems (P<001)

Abstract: PURPOSE To evaluate the bond strengths of two different types of resin bonding systems to coronal dentin and dentin of the pulp chamber floor. MATERIALS AND METHODS 20 extracted human molars were sectioned into three regions; superficial coronal dentin, deep coronal dentin and floor of pulp chamber dentin. The dentin surface of each region was bonded with Single Bond or Clearfil Liner Bond 2V. A core build-up light-cured resin composite, Clearfil Photocore, was placed and light-cured for 40 seconds. After storage in 37 degrees C water for 24 hours, shear bond strengths were measured using a single plane shear test assembly at a crosshead speed of 2.0 mm/minute. Morphological changes of the conditioned dentin and hybrid layer formation were observed by SEM. RESULTS For Single Bond, the bond strengths to superficial dentin were within anticipated bounds (23 MPa), whereas the bond strengths to deep dentin (15 MPa) and floor of pulp chamber dentin (13 MPa) were significantly lower (P < 0.05). For Clearfil Liner Bond 2V, higher bond strengths (approximately 30 MPa) were obtained for each region. The data were analyzed by one- and two-way ANOVA, and Fisher's PLSD (P < 0.05). The appearance of the conditioned dentin varied according to dentin region and conditioner. For Single Bond, thick hybrid layers (3-4 microm) were observed, while thin hybrid layers (less than 0.5 microm) were observed in Clearfil Liner Bond 2V for all regions.

Abstract: PURPOSE To compare 6 shear bond test procedures using 2 primers by evaluating differences in strength and fracture surfaces. MATERIALS AND METHODS Part I - a 2(3)-factorial design evaluated the effects of (1) 2 primer systems, (2) the dentin moisture level, and (3) the application technique defining the bond area. The outcome of Part I then led to choosing for Part II one primer system, applying the primer the entire surface with moist dentin as the substrate while comparing 6 shear test designs: (1) knife-edged chisel-on-iris; (2) similar to 1 with support added to the tooth; (3) chisel on composite plug; (4) similar to 3 with support added; (5) wire loop on composite plug; (6) modified Watanabe assembly. RESULTS In Part I mean shear bond strengths (SBS) ranged from 14-36 MPa. SBS was highest for either primer when it was applied to moist dentin over the entire dentin surface. Each of the factors, moisture level, primer system and application technique significantly affected SBS (3-way ANOVA, P<0.05). The effects from each primer system on SBS depended on the surface moisture or the application technique, indicating significant interactions. In Part II, mean SBS ranged from 18-32 MPa with Groups 1 and 2 having significantly higher bond strengths than the others (P<0.05).

Abstract: PURPOSE To examine and compare the effect of increasing the priming time and the adhesive resin pre-curing time on shear bond strength of new dentin bonding systems (DBS). MATERIALS AND METHODS Two multi-step/total etch DBS, Scotchbond Multi-Purpose Plus (SBMP+) and OptiBond FL (OB FL), and one one-bottle/total etch DBS, Single Bond (SB), were used. One hundred flat dentin specimens were prepared from extracted human molars. Approximately 1 mm of dental structure was ground to expose superficial dentin. The specimens were randomly assigned to the three DBS, and minimum of five specimens were used for each test condition. For each multi-step DBS, 40 specimens were divided into four groups with priming times of 10, 20, 30, and 40 seconds. Each group was further subdivided into two subgroups with adhesive resin pre-curing times of 20 and 40 seconds. The SB specimens were divided into four subgroups with a waiting time of 10, 20, 30, and 40 seconds before drying and curing of its one-bottle adhesive. Shear bond strength tests were performed using a universal testing machine (Instron) at a crosshead speed of 0.5 mm/minute. Results were analyzed using ANOVA and Duncan's multiple range tests. RESULTS For the multi-step DBS, increasing the priming time up to 30 or 40 seconds caused a significant increase in the mean shear bond strength values (P < 0.0001). Lengthening the adhesive resin pre-curing time did not cause any significant increase (P = 0.05) in the mean shear bond strength values except with 30-second and 40-second priming times. For SB, increasing the one-bottle adhesive waiting time before drying and curing to 30 seconds resulted in a statistically significant increase (P < 0.002) in the mean shear bond strength.

Abstract: Purposes (1) To determine the radiopacity of one titanium and seven fiber-reinforced resin posts by densitometric analyses of radiographs, taken from the separate posts and from posts after seating in extracted root-treated human canine teeth with and without a radiopaque luting resin, respectively, and (2) To receive a ranking order by 20 dental practitioners of 16 randomly selected radiographs (2 for each post brand) by radiodensity and by acceptability assessment of the posts' radiographic appearance. Materials and methods One reference titanium post (1) and the following 7 commercial fiber post brands were investigated: AEsthetiPlus/RTD (2), FiberKor/Jeneric Pentron (3), Light-Post/RTD (4), LightPost/Dentatus (5), Mirafit/Hager & Werken (6), Snowlight/Carbotech (7), and Snowpost/Carbotech (8). Standardized radiographs of the separate posts and of posts in extracted canines both before cementation and after cementation with Panavia 21 EX were produced and evaluated densitometrically together with a reference aluminum step-wedge. The cemented posts' radiodensities were determined from radiographs taken without and with 10 mm Plexiglass shielding. The optical densities were recorded in mm Al equivalents. Sixteen radiographs (2 for each post) were presented in random order to 20 dentists for ranking by decreasing radiopacity and by clinical acceptability scores from good (1), adequate (2), acceptable (3), not acceptable (4), to no radiopacity (5) of the posts' radiographic appearance. Statistical evaluation by ANOVA and Duncan post-hoc test at P Results Statistically the posts' radiodensities were significantly different. For separate and cemented posts, recorded from radiographs of Plexiglass shielded specimens, respectively, the following Duncan rankings were obtained: 1>7, 8>3>2, 4, 5>6 and 1>7, 8> 3, 5, 2, 6>6, 4. The dentist ranking by radiopacity scores was 1>7, 8>3>5,6>4>2, and by clinical acceptability scores 1>7, 8>3>2, 4, 5, 6. The titanium post (1) and posts 7 and 8 received scores better than acceptable, post 3 was assessed acceptable, whereas posts 2, 4, 5 and 6 were characterized as "not acceptable" or "not radiopaque".

Abstract: PURPOSE To examine the clinical performance of two-unit cantilevered resin-bonded fixed partial dentures that were inserted at The Prince Philip Dental Hospital, Hong Kong by students and staff between 1992 and 1998. MATERIALS AND METHODS A search of the Hospital computer records system revealed a list of 130 patients who had received two-unit cantilevered resin-bonded fixed partial dentures (RBFPD) placed more than 24 months previous to the review date. For each patient clinically examined, the following data were recorded: gender, age, operator, cementation date, endodontic treatment if performed, bone support, tooth mobility, the presence of shimstock contacts on abutment or pontic in intercuspal position, the presence of interproximal contacts adjacent to the prosthesis assessed by dental floss. Date of any debonds with subsequent treatment was recorded and the patient was asked qualitative questions about their prosthesis. RESULTS 82 prostheses were placed in 69 patients and were found to have a mean service life of 36.7 +/- 15.4 months and a range of 4.3 months to 95.4 months. In total, four prostheses were reported to have debonded resulting in a clinical retention rate of 95.1%. No rotation, drifting or tipping was observed for any of the prostheses during the time of this study. Overall patients' satisfaction with RBFPDs was good with an average assessment rating of 8.2.

Abstract: Purpose To compare in vitro the efficacy of five resin-based desensitizing agents at reducing human dentin permeability and to compare their cytotoxicity. The tested hypothesis was that their different curing techniques cause variations in efficiency and cytotoxicity. Materials and methods Dentin slices (0.5 +/- 0.05 mm thick) were prepared from human third molars (10 per group) and their hydraulic conductance was recorded before and after application of one of the desensitizing agents with a Flodec device. Six desensitizing agents were studied: one light curing agent (Seal and Protect); one self-curing agent (Pain Free); the resin-based agents without any polymerization initiator (Health-Dent, Gluma Desensitizer, Isodan); one oxalate-based agent served as a control (Protect). A MTT assay on L 929 fibroblasts was performed to measure the cytotoxicity of the six desensitizing agents applied onto additional dentin slices (10 per group). Results All the desensitizing agents resulted in a large decrease in dentin permeability. The best results were obtained with Gluma Desensitizer, Isodan, Pain Free and Protect. A statistically significant difference was found among the materials (P = 0.001). All the materials were non-cytotoxic. Cell viability ranged from 88% for Seal and Protect to 100% for Isodan. No difference was found among their cytotoxicity.

Abstract: Purpose To determine, whether different tooth colored materials and application techniques influence the proximal contact strengths (PCS) in vitro. Materials and methods Standardized MO-cavities for direct restorations were prepared into 360 artificial lower first molars. Eight groups were formed (n = 45) and restored with amalgam (1), low (2, 3), medium (4, 5) and high (6, 7) viscosity hybrid composites and compared to the original contact strengths of the unprepared teeth (8). The restored teeth were mounted into a socket simulating physiological tooth mobility. PCS were quantified by measuring the forces necessary for passing the proximal contact with floss under standardized conditions using a universal testing machine. Results PCS ranged from 1.32 +/- 0.56 N for the low viscosity composite to 9.90 +/- 1.98 N for the Amalgam restoration. Medium (5.65 +/- 1.08 N) and high viscosity hybrid composites (5.90 +/- 1.45 N) inserted in a multi-layer technique showed no statistically significant differences to the original PCS of the unprepared teeth (5.76 +/- 0.53 N).

Abstract: PURPOSE A randomized, double blind clinical trial was conducted to evaluate initial color improvement and post-treatment color retention following vital bleaching with a strip-based tooth whitening system. MATERIALS AND METHODS After balancing for baseline color, 57 healthy adults were randomized to either whitening strips with a 5.3% hydrogen peroxide bleaching gel (Crest Whitestrips) or placebo strips without hydrogen peroxide. Maxillary and mandibular anterior teeth were treated twice daily for 30 minutes each over a 2-week period, and efficacy was measured objectively by comparing digital images of teeth collected at baseline, end-of-treatment (Week 2) and 6 months after treatment (Month 6). RESULTS The whitening strip group experienced a highly significant (P< 0.0001) reduction in yellow of -2.0 deltab* units versus baseline and -1.95 deltab* units versus placebo, with similar results noted for the other color parameters in the study. Most of the initial color change remained at 6 months post-treatment, with the whitening strip group continuing to demonstrate highly significant (P< 0.0001) improvements in tooth color relative to baseline and placebo. Age was found to significantly contribute to initial color improvement, with younger subjects experiencing a greater initial reduction in yellowness compared to older participants, but not to post-treatment color retention. The whitening strips were well tolerated, with minor tooth sensitivity and oral irritation representing the most common findings during treatment. There were no persistent or new treatment-related adverse events during the 6-month monitoring period.

Abstract: PURPOSE To evaluate the interface with tooth structure, mode of failure and stability of Fuji Bond LC (FBLC) resin-modified glass-ionomer bonding system MATERIALS AND METHODS The study was in three main parts The first part with interfacial characteristics of FBLC The micropermeability of the FBLC/dentin interface of restored cavities in extracted teeth, after fluorescent dye was introduced into the pulp chamber, was assessed by confocal microscopy In other teeth, confocal microscopy was also used to examine trhe failure of FBLC bonded to flat dentin surfaces, on shear loading In the second part, cervical cavities restored with FBLC (with and without light-curing) and a resin-based composite were examined for stability of the interface over the first 15 minutes In the last part of the study, a new fluorescent dye was mixed with FBLC for restoration of cavities and subsequent examination using 2-photon imaging techniques RESULTS FBLC adapted well to tooth structure, had an interface with dentin that was permeable to fluid and displayed the absorption layer Shear loading at the dentin interface resulted in complex failure with areas of cohesive failure where the absorption layer was present Light-curing of FBLC seemed to produce a stable restorative while "co-curing" resulted in an unstable situation, with the appearance of an emmisable exudate from the FBLC Advanced fluorescent imaging of the material itself seemed to suggest that there was a movement of aluminum ions in a manner similar to other glass-ionomer cements The presence of HEMA in the matrix of the cement associated with the absorption layer was also demonstrated