Diagnostic accuracy of intraoral film and direct digital images for detection of simulated recurrent decay.

UNLABELLED: This study compared the diagnostic accuracy of bitewing images for detection of simulated recurrent caries using the following imaging modalities: Ektaspeed Plus film and different digital imaging system technologies comprised of a charge-coupled device (CCD) based digital imaging unit, a photo-stimulable phosphor (PSP) based unit and contrast- and brightness-enhanced PSP images. STUDY DESIGN: Twenty-four extracted posterior teeth with MOD inlay preparations were secured in models simulating a natural arrangement of teeth. Lesions were created in proximal boxes using dental burs of varying sizes. Defects were filled with wax and plaster and preparations were restored with composite or amalgam. RESULTS: Averages of receiver operating curve areas (Az) revealed diagnostic performances of Az = 0.74 for film, Az = 0.80 for CCD, Az = 0.73 for unenhanced PSP and Az = 0.64 for enhanced PSP. The differences between these means were significant (MANOVA p < 0.0001). Unenhanced PSP produced significantly poorer performance than other modalities. CCD performance was not significantly better than enhanced PSP. Lesions under radiopaque composite restorations were easier to detect, followed by those under amalgam and radiolucent composites across imaging modalities and lesion locations. Based on lesion location, those located at the buccal point angle were easiest to detect, followed by those at mid-gingival floor and lingual-point angle sites. CONCLUSIONS: Contrast and brightness-enhanced digital images enabled better signal detection and a comparable performance with film for detection of artificially induced recurrent caries.

Eighteen-month clinical evaluation of a filled and unfilled dentin adhesive.

OBJECTIVE: The purpose of this study was to evaluate the performance of a filled (OptiBond Solo) and an unfilled (Prime & Bond 2.1) "one-bottle" adhesive in Class V restorations after 18 months of clinical service. METHODS: Thirty-three patients with non-carious cervical lesions were enrolled in the study. A total of 101 lesions were restored using one of the adhesives and a hybrid composite resin. Enamel was not beveled, nor was any mechanical retention placed. The restorations were evaluated at baseline, and at 6 and 18 months after placement using modified USPHS criteria. RESULTS: Cumulative 18-month retention rates were 93.6% for OptiBond Solo and 98.0% for Prime & Bond 2.1. The difference in retention rates was not statistically significant. For OptiBond Solo, the only notable problems were interfacial staining and marginal adaptation, both of which were less than ideal in 9% of restorations. Marginal problems were slightly less frequent for Prime & Bond 2.1 restorations, but the difference was not significant. CONCLUSIONS: Both adhesives provided Class V retention rates exceeding the 18-month, full acceptance guidelines set by the American Dental Association. Any additional benefit provided by the use of a filled adhesive was not detected in this 18-month clinical trial.

Clinical evaluation of Prime & Bond 2.1 for treating cervical dentin hypersensitivity.

PURPOSE: To evaluate the effectiveness of a "one-bottle" dentin adhesive for reducing or eliminating hypersensitivity in exposed cervical dentin. MATERIALS AND METHODS: Eight patients with hypersensitive teeth were enrolled in this clinical trial. The hypersensitive teeth included a total of 22 premolars and anterior teeth with exposed cervical dentin that was sensitive to cold or other stimuli. A single layer of Prime & Bond 2.1, an acetone-based "one-bottle" adhesive, was applied to the cervical dentin and was light-cured. Sensitivity to compressed air and cold stimuli was determined immediately before and after treatment, and at periods ranging to 24 wks after treatment. Patient responses to the stimuli were timed, and were also evaluated by the use of a visual analogue scale. RESULTS: Application of a single coat of Prime & Bond 2.1 significantly reduced cervical dentin hypersensitivity to both compressed air and cold stimuli immediately after treatment. The reduction in hypersensitivity remained significant at 24 wks after treatment.

Effect of finishing technique on the microleakage and surface texture of resin-modified glass ionomer restorative materials.

PURPOSE: The purpose of this study was to evaluate the effects of wet and dry finishing/polishing procedures on the microleakage and surface texture of resin-modified glass ionomer (RMGI) restorative materials. MATERIALS AND METHODS: Class V cavity preparations were made at the cemento-enamel junction (CEJ) on the buccal and lingual surface of 30 extracted human molars. The teeth were restored in three groups of 10 (20 preparations in each group) using Fuji II LC and Vitremer, both RMGIs, and Fuji II, a capsulated conventional glass ionomer cement (control). One restoration per tooth was finished/polished with copious applications of water and the other was finished/polished without water. All restorations were finished/polished using a sequence of four abrasive disks. Finishing/polishing was initiated according to manufacturers' instructions-immediately after light-curing Fuji II LC and Vitremer, and 15min after placement for Fuji II. The specimens were thermocycled and subjected to a silver nitrate leakage test. Each tooth was sectioned buccolingually and examined with an optical microscope at 40x to determine the extent of microleakage at enamel and dentin margins. The data were subjected to a non-parametric statistical analysis. To evaluate surface roughness after polishing, three disks each of Vitremer and Fuji II LC were fabricated in Teflon molds. One disk of each material was not finished/polished (control). The others were finished/polished using Sof-Lex abrasive disks. One specimen of each material was kept wet during all finishing/polishing procedures, while the other was kept dry. Atomic force microscopy was used to determine the average roughness (R(a)) of the specimens. RESULTS: For each material, microleakage at the enamel margin was very slight. Leakage of the conventional glass ionomer Fuji II was severe at dentin margins. Statistical analysis indicated that both Vitremer and Fuji II LC had significantly less leakage than Fuji II, and that Vitremer had significantly less leakage than Fuji II LC (p<0.05). Leakage at enamel margins was significantly less than at dentin margins. Differences related to wet and dry polishing were not statistically significant. Profilometry data indicated that polished specimens were rougher than those cured against a Mylar strip. Wet polishing created greater surface roughness than dry polishing. CONCLUSIONS: RMGIs rather than conventional glass ionomers should be used in Class V cavity sites to allow immediate finishing and to reduce the incidence of microleakage. Dry finishing of RMGIs with abrasive disks is recommended because it produces a smoother surface and does not contribute to microleakage. However, wet finishing of conventional glass ionomers is still recommended to avoid desiccation.

The effect of depth of dentin demineralization on bond strengths and morphology of the hybrid layer.

Previous studies have shown that different phosphoric acid-based etchants do not penetrate intertubular dentin to the same depth. The purpose of this study was to determine the effect of different phosphoric acid-based conditioners on dentin shear bond strengths of three one-bottle bonding systems and to evaluate the corresponding interfacial ultramorphology. The null hypothesis to be tested was that no correlation could be established between the depth of intertubular demineralization and dentin shear bond strengths. The labial surface of 90 bovine incisors was polished to expose middle dentin. The specimens were randomly assigned to three one-bottle adhesive systems (n = 30): OptiBond SOLO, Permaquick PQ1, and Single Bond. For each adhesive system the specimens were divided into three subgroups of different silica-thickened etching gels (n = 10): 37.5% phosphoric acid gel (Kerr Gel Etchant), 35% phosphoric acid gel (Ultraetch), and 35% phosphoric acid gel (Scotchbond Etching Gel). After 24 hours in water at 37 degrees C, the specimens were thermocycled for 500 cycles in baths kept at 5 degrees C and 55 degrees C and the shear bond strengths measured. The data were analyzed with one-way and two-way ANOVA. Further, the adhesives were applied to 800 microns-thick bovine dentin disks (two per subgroup), which were restored with a low-viscosity composite resin. Six small dentin/resin sticks with a cross-section of 1.0 mm x 1.0 mm were obtained from each bonded disk. They were then decalcified in a buffered solution of EDTA, fixed, stained, and sectioned in 90 nanometer-thick slices to observe under the Transmission Electron Microscope (TEM). The mean shear bond strengths were not statistically different at a confidence level of 95%. When the means were pooled for dentin adhesive and for etching gel, the number of cohesive failures was greater for Permaquick PQ1 and for Ultraetch, respectively. Pearson's correlation coefficient showed no correlation between hybrid layer thickness and bond strengths. The ultramorphological observation showed that all materials penetrated the dentin and formed a hybrid layer, regardless of the etching gel used.

Two-year clinical evaluation of tooth whitening using an at-home bleaching system.

PURPOSE: The purpose of this study was to evaluate the 2-year effectiveness of a carbamide peroxide at-home bleaching gel used to provide tooth lightening treatment. MATERIAL AND METHODS: Twenty-nine patients participated in the original study, during which they treated their maxillary teeth with a 10% carbamide peroxide gel nightly for 2 weeks. Shades were determined before and after treatment by comparison with a Vita shade guide. Twenty-four patients (a recall rate of 83%) were recalled for evaluation 2 years after the initial bleaching treatment. The shade of the maxillary incisors was evaluated and compared with shades before, immediately after, and at 6 months and 2 years after initial treatment. Data were analyzed using a repeated-measures analysis of variance. RESULTS: At 2 years after bleaching with a 10% carbamide peroxide gel, the median shade was D2, a six-increment difference from the baseline median of D3. Twenty of 24 patients (83.3%) had a shade change of two or more units, which is the threshold value for bleaching efficacy using American Dental Association guidelines. The lightening result remained statistically significant (p < .0001) at 2 years. CLINICAL SIGNIFICANCE: Although some reversal of the lightening effect occurs over time following the original bleaching treatment, loss of the lighter color appears to be gradual for most patients. Although the longevity of the lightening effect remains to be determined, this clinical trial indicates that the majority of patients have a satisfactory result 2 years after treatment.

Seventeen-year clinical study of ultraviolet-cured posterior composite Class I and II restorations.

OBJECTIVES: To compare the clinical performance of four commercial ultraviolet light-cured composite materials, and to evaluate curing-system effects on long-term wear resistance of Class I and II restorations. MATERIALS AND METHODS: Approximately 32 samples of each of four different ultraviolet light-cured composites (n = 130) were inserted into conventional Class I and II cavity preparations by two clinicians. Cavosurface margins of the preparations were not beveled. Enamel walls of the preparation were etched, and the respective bonding agent was applied. Each restoration was evaluated by two clinicians at 5, 10, and 17 years. Direct evaluations were performed using modified United States Public Health Service (USPHS) criteria. Indirect evaluations were performed using the Leinfelder cast evaluation method. RESULTS: After 17 years, 65% of the restorations were recalled and pooled direct evaluations were conducted for color matching (94% alfa), marginal discoloration (100% alfa), marginal integrity (100% alfa), secondary caries (92% alfa), surface texture (72% alfa), and anatomic form (22% alfa). Mean occlusal wear from indirect evaluations at 5, 10, and 17 years was 197 +/- 85 microns, 235 +/- 72 microns, and 264 +/- 80 microns, respectively. For direct and indirect evaluations there were significant differences (p < or = .05) between the baseline and 5-year recall evaluations. CLINICAL SIGNIFICANCE: This study demonstrated that the mean pooled occlusal wear of four ultraviolet light-cured posterior composites at 17 years was 264 microns (approximately 0.25 mm), and that most wear (75%) occurred in the first 5 years. Of all recalled restorations, 76% were judged clinically acceptable at 17 years, and 22% of those exhibited no clinically detectable wear.

Bond strengths of conventional and simplified bonding systems.

PURPOSE: To compare the shear bond strengths of composite to dentin using conventional (three-component) and simplified (two-component) adhesive systems. MATERIALS AND METHODS: 100 bovine teeth were mounted in phenolic rings and ground to 600-grit to obtain 90 flat facial dentin surfaces and 10 flat facial enamel surfaces. The dentin specimens were assigned to nine treatment groups of 10 teeth each. Three groups were assigned to conventional, three-component bonding systems: All-Bond 2, OptiBond FL, and Scotchbond Multi-Purpose Plus. Six groups were assigned to simplified, two-component bonding systems: Clearfil Liner Bond 2, Fuji Bond LC, One-Step, OptiBond Solo, Prime & Bond 2.1, and Tenure Quik with Fluoride. The enamel specimens were used as the control group with Scotchbond Multi-Purpose Plus Adhesive. Each ground surface was first conditioned according to the manufacturers' directions. After rinsing, the surface of each specimen was left visibly moist prior to application of the bonding system. Each bonding system was applied according to its manufacturer's directions. The corresponding composite restorative materials were applied in 4.4 mm diameter molds to the adhesive surface and light-cured from four directions. The completed specimens were stored in water 48 hours before testing. Shear bond strengths were measured using an Instron universal testing machine. Data were subjected to one-way ANOVA and Tukey's multiple comparison test. RESULTS: Mean shear bond strengths of the conventional systems ranged from 16.3 to 20.6 MPa. Mean shear bond strengths of the simplified systems ranged from 14.7 to 17.4 MPa. The mean shear bond strength of the control (enamel bonding) was 21.4 MPa. The mean shear bond strengths of the conventional and simplified systems were not significantly different from each other or from the control system.

Clinical evaluation of two carbamide peroxide tooth-whitening agents.

A blinded study was conducted to evaluate the efficacy and safety of a dentist-prescribed, accelerated carbamide peroxide tooth-whitening system. Fifty-one patients with discolored teeth completed a clinical trial using an overnight bleaching regimen. One group used an experimental bleaching (whitening) regimen with 10% carbamide peroxide bleaching paste, and another group used the Colgate Platinum Professional Overnight Whitening System. The study included an initial 1-week control/compliance phase using a placebo gel, followed by a 1-week active phase using the assigned bleaching agent. The shade of each participant's maxillary anterior teeth was evaluated by 2 trained and calibrated evaluators at the start of the control/compliance phase, the beginning of the active phase, and days 3, 5, and 7 of the active phase. A value-oriented Vita shade guide with 16 rankings was used to measure color changes, and the number of shade guide units of change (delta sgu) was calculated. Potential side effects, such as tooth hypersensitivity and gingival irritation, also were assessed at each recall examination, as well as recorded by the patients in their daily diaries. At the end of the 7-day active phase, the mean delta sgu for the group using the experimental bleaching agent was 7.1 +/- 2.4, and for the Colgate Platinum Overnight group, the delta sgu was 7.5 +/- 2.2. There were no statistically significant (p > or = 0.05) differences between the results of both groups at the 0-, 3-, 5-, and 7-day evaluations. After 7 days, the change in shade guide units for both groups ranged from 3 to 13 units, far exceeding the minimum required change by the American Dental Association Guidelines (delta sgu = 2 units) for demonstrating efficacy. There was no statistical difference in the whitening achieved at day 5 vs. day 7 for either tooth-whitening group. There were no notable changes in any gingival, bleeding, or plaque indexes for the 50 patients completing the active phase. The number of days of mild tooth sensitivity during the active phase was 0.9 +/- 1.3 days for the experimental agent group and 1.1 +/- 1.5 days for the Colgate Platinum group.

Effect of polymerization mode on bond strengths of resin adhesive/cement systems.

PURPOSE: The purpose of this study was to examine the effect of resin adhesive/cement system primer and cement polymerization mode (auto- vs dual-polymerized) on the shear bond strength to dentin. MATERIALS AND METHODS: Dentin surfaces of 90 bovine teeth were polished to 600 grit. The dentin was etched for 15 seconds with phosphoric acid, rinsed, and blotted. Three adhesive systems, All-Bond 2, Prime & Bond 2.1 Dual-Cure, or Scotchbond Multi-Purpose Plus, were applied. Three primer polymerization methods were used with each system: dual-polymerized, autopolymerized, or strictly following manufacturers' recommendations. Resin cements, which were also either auto- or dual-polymerized, were applied to dentin using gelatin capsules. Shear bond strengths were determined using an Instron universal testing machine. RESULTS: The greatest bond strength, 15.4 MPa, was found with the Scotchbond system when the primer was dual-polymerized and the cement was autopolymerized. The lowest bond strength, 7.5 MPa, was found with All-Bond 2/Duo-Link, when the primer and cement were dual-polymerized. The autopolymerization mode produced the highest mean bond strength for All-Bond 2, while dual-polymerization of primer and cement resulted in the highest mean bond strength for Prime & Bond 2.1. Scotchbond Multi-Purpose Plus was least affected by the polymerization method. Two-way ANOVA showed that the interaction between the type of adhesive system and the method of polymerization significantly influenced bond strength (p = .0001). CONCLUSIONS: The effect of the primer polymerization method on ultimate bond strength was different for each adhesive system evaluated. More research is needed to elucidate the interaction between adhesive system and method of polymerization on bonding of resin cements to dentin.

Bond strengths of a new dentin adhesive system.

PURPOSE: This in vitro study evaluated the shear dentin bond strengths of EBS, a new three-component adhesive system containing an aqueous primer. Two other adhesive systems (Scotchbond Multi-Purpose and OptiBond FL) were included in the study for comparison. A simple tensile test and the effect of composite restorative material on shear bond strength were also evaluated. MATERIALS AND METHODS: Eighty bovine teeth were obtained, embedded in acrylic, polished to 600 grit to form standardized dentin specimens, and randomly assigned to eight treatment groups. Resin composite was placed in gelatin capsules and bonded to dentin using the three adhesive systems. Each system was used according to manufacturers' instructions on dentin that was blotted to remain moist after etching. Each bonding system was used with its own manufacturer's composite material, and EBS and OptiBond FL were also used with a higher modulus composite, Z100. Specimens were stored in water for 24 hours, and bond strengths were determined using an Instron universal testing machine. RESULTS: EBS/Pertac II had a mean shear bond strength of 17.2 MPa, which was significantly less than Scotchbond Multi-Purpose/Z100 (22.5 MPa) but similar to OptiBond FL/Herculite (16.4 MPa). Shear bond strengths of EBS and OptiBond were only slightly higher when they were used with Z100 composite. Tensile bond strengths were less than shear bond strengths but were nearly identical for all three systems (range: 8.0-9.8 MPa).

Shear bond strengths of one-bottle dentin adhesives using multiple applications.

This study evaluated the effect of multiple applications of the one-bottle adhesives Prime & Bond, One-Step, and Tenure Quik on the shear bond strength of composite to dentin. In addition, the study examined the effects of surface moisture and dual-cure composite on bond strengths of One-Step and Tenure Quik respectively. The adhesive systems were bonded to the occlusal dentin of extracted human teeth. Control group specimens received only two applications of adhesive, as recommended by the manufacturers. Two experimental groups of each system received a greater number of adhesive applications. Additional experimental groups using only two adhesive applications were made to test modifications in surface moisture and composite type for One-Step and Tenure Quik. Shear bond strengths were determined using an Instron Universal Testing Machine. The mean shear bond strength of the Prime & Bond control group was significantly greater than that of the other two control groups. Multiple applications of adhesive decreased the bond strength of each system, but the difference was significant only for four applications of One-Step. The method of moisture removal (compressed air or blotting) had no effect on shear bond strength of One-Step. The shear bond strength of Tenure Quik was not affected by the type of composite used. Prime & Bond had significantly higher shear bond strengths to dentin than either One-Step or Tenure Quik. Both Prime & Bond and One-Step had significantly higher bond strengths than Tenure Quik.

Effects of viscosity and surface moisture on bond strengths of resin-modified glass ionomers.

PURPOSE: To evaluate the effects of surface moisture and material viscosity on the shear bond strength of resin-modified glass ionomers to dentin. MATERIALS AND METHODS: Sixty human teeth were mounted in phenolic rings and ground to obtain flat facial and lingual dentin surfaces. The specimens were assigned to six treatment groups. Three groups were first conditioned with 10% polyacrylic acid. On one surface of each specimen, dentin was left visibly moist prior to application of the restorative material. On the opposite surface the dentin was dried, but not desiccated, after conditioning. For these three groups, Fuji II LC resin-modified glass ionomer was mixed at powder/liquid (P/L) ratios of 1.4, 3.0 and 3.6 and applied to the conditioned dentin in 2.5 mm diameter molds. The other three groups were treated with Vitremer primer. One surface of each specimen was "dry" and one surface was "moist" before primer application. Vitremer restorative material was mixed at P/L ratios of 2.2, 2.5 and 2.8 and applied to the primed surfaces. Shear bond strengths were measured using a universal testing machine. Data were subjected to three-way ANOVA and Tukey's multiple comparisons test. RESULTS: Mean shear bond strengths of the two materials ranged from 6.9 to 10.4 MPa and varied little regardless of the viscosity of the materials or the degree of surface moistness. The differences among viscosities and surface moistness were not statistically significant. IN this in vitro study, the shear bond strengths of two resin-modified glass ionomers were unaffected by the viscosity of the materials and the surface moisture of the dentin substrate.

Effect of a surface sealant on microleakage of Class V restorations.

PURPOSE: To evaluate the effect of a low-viscosity surface-penetrating sealant on microleakage around Class V restorations. MATERIALS AND METHODS: Box-shaped Class V preparations were made in the facial and lingual surfaces of 50 extracted human teeth. Occlusal margins were in enamel and gingival margins were in dentin/cementum. Preparations were restored with the following systems (n = 20): Dentin Conditioner + Fuji II LC; ProBond primer + VariGlass VLC; OptiBond + XRV Herculite; Scotchbond Multi-Purpose + Silux Plus; and Scotchbond Multi-Purpose + Restorative Z100. Half of the restorations in each group were randomly selected and sealed with Fortify resin immediately after finishing and polishing. Specimens were thermocycled 500x between 5 degrees and 55 degrees C and subjected to a silver nitrate microleakage test. Penetration of the silver nitrate tracer was evaluated and recorded using a 0-4 ordinal scale. Data were analyzed using non-parametric statistical tests. RESULTS: All of the restorative systems had very little leakage at enamel margins, regardless of whether the resin sealant was used. Each of the systems except VariGlass had minimal leakage at unsealed dentin margins also. Application of the resin sealant significantly reduced leakage at the interface between VariGlass and dentin or cementum, but had no effect on the other restorative systems.

Pre-admission credentials and dental school performance of dental hygienists.

This study examined the effect of dental hygiene preparation prior to entering dental school on dental school performance. Study participants included 203 female students who entered a public dental school from 1980-1989. Groups 1 and 2 had completed dental school prerequisites and a dental hygiene curriculum in a community college setting (n = 19) or university setting (n = 22) respectively, and Group 3 (n = 162) were traditional students with no dental hygiene education. Preadmission variables were predental science and non-science grade point averages (GPA) and Dental Admission Test (DAT) scores. Performance variables were GPA of years one and two of dental school and National Board scores (Part 1). Results showed that Group 2 hygienists had significantly lower predental science GPAs than Group 1 or 3 and significantly lower non-science GPAs than Group 3 (p < 0). Both groups of hygienists had significantly lower DAT scores than Group 3 (p < 0). No difference was seen in first and second year GPAs or the National Board average. Adjusting performance scores to compensate for deficiencies in preadmission variables showed that Group 2 hygienists had significantly higher adjusted first-year GPAs and National Board averages than Group 3 (p < 0). Thus, hygienists performed as well as non-hygienists in spite of weaker admission credentials.

Five-year clinical study of u.v.-polymerized posterior composites.

Four u.v.-polymerized composites (Estilux, Nuva-Fil, Nuva-Fil P.A. and Uvio-Fil) were clinically evaluated in Class I and II cavity preparations in permanent teeth. The restorations were evaluated at baseline, 1, 2, 3, 4 and 5 years using USPHS criteria for direct evaluation and at 3, 4 and 5 years using the Leinfelder method for indirect evaluation of wear. The wear measured by the USPHS method showed increasing wear rates in earlier reports, apparently due to the limited sensitivity of the scale to early wear. The wear by the Leinfelder method showed gradually decreasing wear rates. There were no statistically significant differences among the wear values for the four u.v.-cured materials or between these materials and the self-cured and visible light-cured controls.