Prototyping of increased vertical dimension of occlusion using an existing removable partial denture and composite resin: a case report.

Full-mouth rehabilitation can be challenging due to the complexity of restoring the vertical dimension of occlusion (VDO) and replacing missing teeth. In partially edentulous patients, the concept of a bonded composite resin prototype for increasing the VDO has previously been applied through the use of an overlay removable partial denture (RPD) with acrylic resin covering the existing dentition. Unfortunately, this type of prosthesis does not always accurately model the function and phonetics intended for the definitive prostheses, and the esthetic result often is less than ideal. It would be advantageous if direct bonding could be used with the patient's existing RPD to model the increased VDO, but this approach has not been reported in the literature. This case report describes the direct bonding of an existing RPD to create a prototype for increased VDO in a partially edentulous patient with a skeletal Class II malocclusion. The successful outcome has been maintained for more than 1 year.

24 hour polymerization shrinkage of resin composite core materials.

PURPOSE: The study's purpose was to evaluate the 24-hour polymerization shrinkage of resin composite core materials. MATERIAL AND METHODS: Eleven resin composite core material samples (n = 12) were evaluated using a non-contact imaging device with measurements obtained over 24 h. Shrinkage values were determined corresponding to proposed times involved with CAD/CAM same-day treatment and at 24 h. Shrinkage data was statistically compared using Friedman/Dunn's test for intragroup analysis and Kruskal Wallis/Dunn's test for intergroup analysis, all at a 95% level of confidence (α = 0.05). RESULTS: Mean results identified a wide volumetric shrinkage range with considerable similarity overlap. Inconsistent shrinkage behavior was evident and all materials reached maximum values before 24 h. No significant difference was observed during proposed digital same day all ceramic crown procedures, but some differences were noted at 24 h. CONCLUSIONS: Under this study's conditions results were material specific, at times inconsistent, with wide variation. Shrinkage consistently increased for all products and it is not known if the continued shrinkage magnitude may compromise the stability and fit of all-ceramic crowns at 24 h.

Minimally invasive esthetic improvement in a patient with dental fluorosis by using microabrasion and bleaching: A clinical report.

Dental fluorosis is a condition that produces unesthetic coloration of enamel because of excessive fluoride ingestion during enamel formation. Its appearance can range in severity from mildly white and opaque to dark brown and can lead a patient to seek dental treatment. Historically, these lesions have been masked, either with direct or indirect restorations, but more conservative treatment options are now available, including the combination of microabrasion and bleaching. This clinical report describes the use of these treatment options to address a young patient's dental fluorosis.

Restoration of Anterior Dental Erosion with a Combination of Veneers and Crowns: A 3-Year Case Report.

This report describes the conservative management of a 40-year-old female patient with smooth, eroded facial enamel affecting her maxillary anterior and some posterior teeth. Using conventional enamel bonding, pressed leucite-reinforced laminate veneers were used to restore the length, contour, and esthetics of the maxillary right canine, as well as of the right lateral and both central incisors; at the same time, it was necessary to restore the maxillary left lateral incisor, canine, and first premolar of the same quadrant with all-ceramic crowns of the same material. The patient has been followed for 3 years and demonstrates a good esthetic outcome with no shade discrepancy between the two types of restoration. Apparently, the tooth structure, though eroded, was able to provide an adequate bonding substrate for these adhesive restorations.

Film thickness of crown disclosing material and its relevance to cementation.

STATEMENT OF PROBLEM: Regardless of the type of indirect restoration being fabricated, optimizing fit at cementation is a challenge. Several disclosing agents have been recommended to identify intaglio surface contacts that may result in incomplete seating and poorly adapted margins. The International Organization for Standardization has established a standard of 25 µm for the maximum film thickness for water-based cements. To accurately predict the clinical behavior of a luting cement, the disclosing agents themselves should have a film thickness no greater than 25 µm. PURPOSE: The purpose of this study was to determine the film thickness of 2 disclosing products, a spray-on powder (Occlude Indicator Marking Spray) and a silicone disclosing agent (Fit Checker). MATERIAL AND METHODS: The film thickness of the 2 disclosing products was determined by using optically flat glass cylinders according to the method set forth in International Organization for Standardization Standard 9917 for water-based cements. Because the silicone product is fast setting, the load was applied within 10 seconds of completing the mix. The spray-on product was allowed to dry before applying the load, in accordance with its intended clinical use. The film thickness of both products was determined with a load of 150 N applied for 30 seconds. Additional determinations were made for the silicone product at both 100 N and 50 N applied for 30 seconds and at 150 N applied for 90 seconds. An additional film thickness determination for the spray-on product was made with no load applied. The film thickness data for the various loads and intervals for the silicone product were analyzed with a 1-way ANOVA and the Tukey-Kramer multiple comparison test (α=.05). A t test (unequal variance, 2-tailed) was used to compare the spray-on and silicone products as measured at a load of 150 N applied for 30 seconds. RESULTS: The average film thickness of Fit Checker ranged from 16.7 to 23.7 µm, with the two 150-N groups significantly lower than the others, whereas that of Occlude was 67.7 µm unloaded and 48.4 µm when loaded. The film thickness of Fit Checker was significantly less than that of Occlude for the 150 N, 30-second group. CONCLUSION: Within the limitations of this study design, Fit Checker had a film thickness that satisfied the 25-µm limit imposed on water-based luting cements in the International Organization for Standardization standard, whereas Occlude Spray did not.

Four-year follow-up of the rehabilitation of a mandibular arch with a cementable zirconia-reinforced fixed dental prosthesis: a clinical report.

Implant-supported prostheses have been used extensively to rehabilitate completely edentulous arches. Although combinations of different restorative materials have reportedly been used to fabricate such prostheses, a metal framework is usually chosen for acrylic resin reinforcement. However, cost and the frequent need to section and solder to attain a passive framework fit are disadvantages for using metal. Zirconia has been used widely in restorative dentistry as an alternative to metal. This clinical report describes the fabrication of a zirconia-reinforced cementable fixed dental prosthesis with a 4-year follow-up.

New method of measuring water permeability of adhesive resin films.

PURPOSE: To adapt a simple gravimetric method to measuring the permeability of adhesive resin films to liquid water, and to compare this to the water vapor permeability of the same resins. METHODS: Using commercially-available permeability cups designed for industrial permeability testing, the loss of mass of water vapor or liquid water from a stainless steel cup sealed with a resin film was measured over 1-2 days. The permeabilities of Parafilm (control), Clearfil SE Bond adhesive, Xeno IV and One-Up Bond F were compared. RESULTS: The lowest resin film permeability was obtained with Clearfil SE Bond adhesive films. The permeabilities ofXeno IV and One-Up Bond F to liquid water were 2.76 and 3.27-fold higher (P < 0.001) than that of Clearfil SE Bond adhesive. Liquid water permeability was always 2.8-3.8-fold higher (P < 0.05) than water vapor transmission rate. It was concluded that quantitative comparisons of the permeability properties of resin films can be made gravimetrically. The large permeability cups that are available commercially may be reduced in size in the future for measuring dentin adhesive films with smaller surface areas that are less liable to contain imperfections.

Resin Bonding of a Lithium-Disilicate Crown Using a Ligated Rubber Dam: A 2-Year Case Report.

Enduring glass-ceramic restorations greatly depend on the quality of adhesion of the crown to enamel and dentin. Proper isolation is vital to the success of bonded ceramic restorations. The rubber dam has long been considered the primary method of preventing contamination of the operating field, a crucial requisite for adhesion. However, many dentists do not use rubber dam isolation due to its penchant for slowing down procedures. The authors present a case report that describes a technique for the indirect bonding of a ceramic restoration to a maxillary first molar using rubber dam isolation in conjunction with a floss ligature,a method that is aimed at optimizing operator effectiveness and efficiency.

Two-year clinical performance of Clearfil SE and Clearfil S3 in restoration of unabraded non-carious class V lesions.

This study was undertaken to evaluate the two-year clinical performance of a self-etching primer and a self-etching adhesive, both of which employ the same acidic monomer. Forty pairs of restorations of AP-X hybrid resin composite (Kuraray Co, Ltd, Osaka, Japan) were placed in caries-free cervical erosion/abfraction lesions. Based on insensitivity to air, the dentin in 62% of these lesions was considered to be sclerotic. The restorations were placed with no abrasion of tooth surfaces, except for cleaning with plain pumice and no use of phosphoric acid etching, which is counter to the manufacturer's instructions that call for etching of unprepared enamel. One restoration from each pair was placed using Clearfil SE Bond, an adhesive employing a self-etching primer, and the other was placed using Clearfil S3 Bond, a self-etching adhesive. To emulate the results likely to occur in a private practice, the restorations were placed by well-educated, experienced clinicians who had no particular expertise in adhesive dentistry research and who placed the restorations according only to their interpretation of the manufacturer's instructions. The restorations were clinically evaluated at baseline and at 6, 12 and 24 months, using modified Ryge/USPHS criteria. For both products, retention of 81%-84% of the restorations was observed over two years, which is lower than has been previously observed with these products and is likely due to limitations in the manufacturer's instructions compounded by inexperience of the operators in adhesive dentistry research. One restoration placed with each adhesive demonstrated secondary caries, which was probably attributable to the study being conducted in a non-fluoridated area and which reduced the percentages of clinically successful restorations to 78%-81%. No statistically significant difference (p = 0.50) between the two adhesives was observed in overall performance.

Minimally retentive gold onlays: a six-year case report.

Partial veneer gold restorations, such as gold onlays, have changed little in preparation design over the past 40 years, as evidenced by textbooks that have long been in print. Such designs must have been based on the assumption that restorations would be luted with zinc phosphate cement but have not altered, despite the introduction of stronger luting cement classes, such as resin composite and resin-modified glass ionomer cements. It is well-established that both porcelain and base metal materials, which have been etched on the intaglio surface, can be combined with resin composite luting cements to produce restorations retained largely through adhesion. However, neither of these materials can equal the combination of minimal tooth reduction and margin adaptation that is possible with high noble gold restorative materials. Although high noble gold alloys cannot be etched, air abrasion of the intaglio surface of restorations likely improves micromechanical retention, but it is unknown whether this, along with a strong luting cement, is sufficient to stabilize high noble gold alloys in preparations with considerably less retention and resistance form than traditional designs.

Film thicknesses of recently introduced luting cements.

STATEMENT OF PROBLEM: A luting cement must maintain a minimum film thickness over a sufficient period of time to allow seating of indirect restorations. The performance of newer luting cements in this regard has not been evaluated. PURPOSE: The purpose of this study was to compare the film thicknesses of 6 luting cements, 2 resin-modified glass ionomer (FujiCEM and RelyX Luting Plus), 2 composite resin (Panavia 21 and RelyX ARC), and 2 self-adhesive resin (Maxcem and RelyX Unicem) cements, over 3 minutes. MATERIAL AND METHODS: The film thickness (microm) of each cement (n=7) was determined at room temperature at 1, 2, and 3 minutes after the start of mixing, according to the testing method set forth in ISO Standard 9917. Means of all cements were compared at the 2-minute interval, and means at the 1- and 3-minute intervals for each were compared to the mean for the same cement at 2 minutes, using 1-way analyses of variance (ANOVA) and Tukey-Kramer multiple comparison tests (alpha=.05). RESULTS: Except for 1 resin-modified material at 3 minutes, a point beyond its specified working time, all materials produced film thicknesses under 30 microm at 3 minutes and under 26 microm at 2 minutes. CONCLUSIONS: All of the materials tested meet the ISO standard of 25-microm maximum film thickness for up to 2 minutes after mixing.

Microtensile dentin and enamel bond strengths of recent self-etching resins.

In this study, the microtensile bond strengths of resin composites to dentin and enamel produced by recently introduced self-etching resins were determined. Included were two adhesives with self-etching primers, Clearfil SE (Kuraray) and Peak SE (Ultradent), four self-etching adhesives, Optibond All-In-One (Kerr), Clearfil S3 (Kuraray), Adper Prompt L-Pop (3M ESPE) and iBond (Heraeus Kulzer) and, as a positive control, PQ1 (Ultradent), an etch-and-rinse adhesive. Each product was evaluated using the same hybrid resin composite, Z250 (3M ESPE). Testing was performed after 48 hours using a "non-trimming" microtensile test at a crosshead speed of 0.6 mm/minute. Sample size was five teeth per group, with the value for each tooth calculated by averaging the bond strengths of seven beams derived from it. Mean values in MPa (SD) for dentin were: Clearfil SE 81.6 (3.5),a Peak SE 80.3 (9.9),a PQ1 73.4 (4.9),a,b Optibond All-In-One 64.4 (5.9),b Clearfil S3 62.5 (2.2),b,c iBond 51.0 (4.0)c and Prompt L-Pop 33.9 (6.4).d Mean values in MPa (SD) for enamel were: PQ1 55.6 (2.5),a Clearfil SE 54.1 (5.4),a Prompt L-Pop 54.0 (5.4),a Peak SE 51.8 (1.5),a,b Clearfil S3 44.3 (5.2),b,c Optibond All-In-One 40.1 (2.1)c,d and iBond 33.8 (3.3).d (Values for each substrate with the same letter were not significantly different, one-way ANOVA, Tukey-Kramer Multiple Comparison Test, p<0.05.) Compared to the positive control, PQ1, only adhesives with self-etching primers, Clearfil SE and Peak SE, were as effective in bonding to both enamel and dentin. With the exception of Prompt L-Pop, scanning electron micrographs of the etched enamel surface produced by self-etching products indicated far less surface topography than conventional etching, even for self-etching primer systems producing the same bond strengths as the etch-and-rinse adhesive.

The effect of subject age on the microtensile bond strengths of a resin and a resin-modified glass ionomer adhesive to tooth structure.

In this study, the microtensile bond strengths of an etch-and-rinse resin adhesive to dentin and enamel and a resin-modified glass ionomer adhesive to dentin were determined on teeth known to have originated from subjects over 60 years of age. The same tests were repeated on teeth originating from young subjects. The resin adhesive was Prime & Bond NT (Caulk/Dentsply), while the resin-modified glass ionomer adhesive was Fuji Bond LC (GC America). Both were paired with the same hybrid resin composite, TPH3 (Caulk/Dentsply). Testing was performed after 48 hours using a "non-trimming" microtensile test at a crosshead speed of 0.6 mm/minute. No significant differences were observed between the young and aged teeth for any comparison (p > 0.05). SEM evaluation of the etched dentinal surfaces demonstrated less depth of decalcification in the intertubular areas of aged dentin, but there was no observable difference within the tubules of young and aged dentin.

Comparison of traditional and low sensitivity whiteners.

This placebo-controlled, double-blind randomized clinical trial compared five 10% carbamide peroxide tooth whitening formulations. Three products contained varying concentrations of potassium nitrate as desensitizers. One contained no desensitizers and one was a placebo. During the two weeks of active bleaching, participants used a daily diary to record the number of days of sensitivity from hot, cold, gums, tongue and/or throat. The total number of days of sensitivity experienced by the participants in each group was compared. Participants using the agent with no desensitizers did not experience any more sensitivity than those using the agent containing 3% potassium nitrate. The products that included 0.5% potassium nitrate and 0.5% potassium nitrate and 0.25% sodium fluoride were not associated with any more sensitivity than the placebo group. In addition, the shade tab change from baseline to 11 weeks following cessation of bleaching was compared. Using an active bleaching agent, no difference in color change was noted among the four groups. All four groups were associated with significantly higher color change than the placebo. The addition of a small percentage of potassium nitrate to a 10% carbamide peroxide tooth whitener was shown to significantly reduce postoperative sensitivity without reducing efficacy.

Sealing properties of mineral trioxide aggregate orthograde apical plugs and root fillings in an in vitro apexification model.

One-visit mineral trioxide aggregate (MTA) apexification is gaining in popularity over the use of calcium hydroxide barriers. This study examined the sealing properties of two MTA apexification procedures using an in vitro apexification model. White MTA was introduced into instrumented single-rooted canals with standardized artificially created open apices to form 3- to 5-mm-thick orthograde apical plugs or complete orthograde fillings of the root segments. The remaining canal spaces in the former group were backfilled with thermoplasticized gutta-percha without a sealer. A Flodec fluid filtration device was used to record fluid flow across filled root canals at 48 hours and after 4 weeks of immersion in phosphate-buffered saline (PBS). Although MTA root fillings exhibited a better seal than MTA apical plugs at 48 hours, seals of these two groups were not significantly different after 4 weeks. Interaction of MTA with PBS may result in apatite deposition that improves the seal of MTA apical plugs with time.

The effect of light curing source on the residual yellowing of resin composites.

PURPOSE: This study evaluated the amount of residual yellow in cured resin composites when polymerizing with either a quartz-tungsten-halogen (QTH) or blue light-emitting diode (LED). MATERIAL AND METHODS: Twelve shades (bleaching to conventional shades) of microfill, hybrid and microhybrid resin composite specimens (n = 10) were polymerized with both light types. All the materials contained only camphorquinone as the photoinitiator. After exposure, the specimens were stored in the dark for 24 hours. Then, the specimen color parameters were recorded (L*, a*, b* and C*(ab)) and color differences (deltaE*(ab)) were determined by examining for changes among the test combinations. Group comparisons were examined using ANOVA and the Tukey-Kramer post-hoc test, and pairwise comparisons were made using the Student's t-tests at a pre-set alpha of 0.05. RESULTS: When a significant difference in the shade of yellow was noted, the QTH light produced a greater yellow tinge than most comparisons using the LED. The potential for producing more residual yellowing could not be anticipated with respect to composite filler classification or shade, as this effect may be more dependent on individual product composition. The extent to which residual yellowing differences were noted between light curing units fell within levels considered detectable by the human eye (deltaE > 2.0). CONCLUSION: The selection of light curing unit to polymerize resin-based restorative materials can have a significant influence on the amount of residual yellow present, with the QTH light tending to leave more yellow than an LED unit.

The effect of chlorhexidine on dentin hybrid layers in vivo.

This in vivo study evaluated by TEM the degradation of dentin hybrid layers in deep occlusal resin composite restorations. Caries-free premolars scheduled for extraction as part of orthodontic treatment were prepared, restored and evaluated after two and six months. The adhesive used was a single-bottle etch-and-rinse product (Single Bond Plus, 3M ESPE). Control group restorations were placed according to the manufacturer's instructions, while the experimental group received application of a 2% solution of chlorhexidine digluconate after etching. No degradation was observed in either group after two months. Slight degradation was found in the control group after six months, but none was observed in the experimental group. In vitro testing showed no significant difference in microtensile bond strength between the control and experimental adhesive protocols.

Effect of restoration size on the clinical performance of posterior "packable" resin composites over 18 months.

Fifty predominantly moderate or large Class II or multiple-surface Class I resin composite restorations were placed in molars under rubber dam isolation. The restorative systems used were: Alert Condensable (Jeneric/Pentron) and SureFil (Dentsply/Caulk). The restorations were classified according to size, with 7 small, 25 moderate and 18 large, of which 8 were cusp replacement restorations. Baseline, 6, 12 and 18-month double-blinded clinical evaluations were carried out using modified USPHS criteria. The independent variables: restorative material, restoration size and three other clinical factors, were tested using a Multiple Logistic Regression procedure to determine if any were predictive of failure. Of the 50 restorations, four failed by the 18-month recall, three failed due to fracture of the restoration and one due to secondary caries. Both restorative systems demonstrated a 92% success rate. No association between restoration size (p = 0.99) or restorative material (p = 0.65) and failure was found. Similarly, the additional variables, occlusal contact type, presence of occlusal wear facets and first or second molar, were not predictive of failure.

Restoration of proximal contact in direct class II resin composites.

Although this technique performed well in the case presented, it becomes more advantageous with larger restorations. This would be especially true for core build-up restorations of missing cusps, although such cusps must be restored prior to placement of separating rings. Clear plastic matrices are available and permit effective curing of resins, but the authors find the preset contours of these matrices not sufficiently adaptable to differing clinical situations and prefer metal matrices, even though these necessitate additional light curing after matrix removal.

The microtensile bond strength of self-etching adhesives to ground enamel.

It is uncertain whether single-phase self-etching adhesives form bonds to enamel as reliable as those of etch-and-rinse adhesives. This study compared the microtensile bond strengths to ground enamel of three self-etching adhesive systems, a self-etching primer system and an etchand-rinse adhesive system. Human enamel was ground flat with 320-grit silicone carbide paper. The self-etching adhesives iBond (Heraeus Kulzer), Prompt L-Pop (3M ESPE) and Xeno III (Caulk/Dentsply), the adhesive with a self-etching primer Clearfil SE Bond (Kuraray) and the etch-and-rinse adhesive Scotchbond Multipur-pose (3M/ESPE) were applied as directed, followed by a core of the same manufacturers' hybrid resin composite. A microtensile bond strength evaluation was performed after 48 hours of water storage, using untrimmed beams approximately 0.9 mm2 in cross-sectional area at a crosshead speed of 0.6 mm/minute. There were no pretest failures in any group, and failures were predominately adhesive or mixed. Adhesion to enamel of Clearfil SE was not significantly different from Scotchbond Multi-Purpose, while the three self-etching adhesive systems demonstrated significantly lower bond strengths (One-way ANOVA, Tukey-Kramer Multiple-Comparison Test, p < 0.00001).