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Two years of clinical experience with Procera titanium crowns.

PURPOSE: The purpose of the study were to evaluate the clinical performance of the Procera porcelain-fused-to-titanium crown system in general practice during a 2-year period, and to evaluate the performance of a new low-fusing porcelain as a veneering material on titanium. MATERIALS AND METHODS: A number of consecutive complete-coverage crowns (40) in 25 patients (14 women and 11 men) with a mean age of 53.1 years (range 35 to 79 years) were made according to the Procera (Nobel Biocare) technique in a 3-month period. The titanium copings were fabricated from solid rods of pure titanium using spark erosion and copy-milling technique, whereafter they were veneered with a new type of low-fusing ceramic material. The crowns were evaluated using the CDA criteria at baseline and after 2 years. RESULTS: The general failure rate was low and was restricted to one carious lesion, one porcelain fracture, and one loss of a crown resulting from failure of retention of a post and core. The most frequent single reason that the "excellent" color level was not recorded was a "too-high value." A slightly dull or granular porcelain surface was observed both at baseline and after 2 years. Overall, the responses of the patients were positive. CONCLUSION: Within the limitations of the study it can be concluded that porcelain-veneered Procera titanium crowns can be used as an alternative to other porcelain-fused-to-metal systems. However, conclusions should be made with caution from the results of this study because of the limited number of patients and crowns and the short observation period.

Adult↗

The 5-year clinical performance of direct composite additions to correct tooth form and position. I. Esthetic qualities.

The aim of the study was to evaluate the esthetic performance of direct composite additions in correcting tooth form and position at 5 years. Composite additions were directly placed using the acid-etch technique and enamel bonding on 87 intact maxillary anterior teeth in 23 young patients (12-19 years old). The restorations were made by one operator using an ultrafine midway-filled densified restorative composite. Color slides were made at baseline and 5 years. At the 5-year recall, esthetic performance was assessed clinically by two evaluators at chair-side in subterms of color match, translucency/opacity, surface roughness, and anatomical form. Five additional examiners scored esthetics on the 5-year slides. Of the restorations, 89% were still esthetically satisfactory after 5 years of clinical service. The remaining restorations needed replacement, mainly because of severe loss of anatomical form, to a lesser degree because of severe color mismatch. Central incisors and small unilateral restorations generally showed the best results concerning color match (68% and 74%, respectively) and surface smoothness (84% and 100%, respectively). The slide scores on color match and translucency/opacity were generally similar or somewhat better than the direct clinical scores; however, the difference were not statistically significant (P > 0.05). As far as surface roughness is concerned, the results were significantly better (P < 0.05) when recorded indirectly than by direct clinical evaluation. In conclusion, direct composite additions are a valuable and effective procedure for esthetic and conservative treatment of malformed and misaligned anterior teeth. Loss of anatomical form due to wear points to a shortcoming of the composite material used, with which a durable esthetic result cannot always be guaranteed in the long term.

Adolescent↗

A multicenter longitudinal clinical trial of a new system for restorations.

STATEMENT OF PROBLEM: A new method for fabrication of crowns and fixed partial dentures (Procera system) that involves electric discharge machining and copy milling has been developed. The metal used is unalloyed titanium, which can be processed as a single coping or multiple units joined to a pontic by laser welding. PURPOSE: The single-unit coping or the fixed partial denture (FPD) substructure is then veneered with a low-fusing porcelain. MATERIAL AND METHODS: In this article the clinical application of this technique was evaluated by six major universities in the United States. A total of 114 patients participated in this study, which involved 126 restorations (55 maxillary and 71 mandibular prostheses). There were 179 abutments, of which 73 were crowns and 53 were three-unit FPDs. Surface and color, anatomic form, and margin integrity were assessed 1 month after cementation and at 1 year with the California Dental Association (CDA) quality assessment evaluation system. RESULTS: No statistically significant differences in CDA scores between the 1 month evaluations and the 1 year assessments were found for surface and color (p = 0.68), anatomic form (p > 0.99), or margin integrity (p = 0.57). By use of the lowest ranking in the three categories as the overall quality of the restoration, only 3.3% (two crowns and two FPDs) were not acceptable at the 1-month visit and 4.5% (two crowns and three FPDs) were not acceptable at the 1-year evaluation. At-the 1-month visit 96.6% (114) of the restorations were considered to be satisfactory, whereas 95.5% (107 restorations) were evaluated similarly at the 1-year evaluation. CONCLUSIONS: The Procera system demonstrated, by use of the CDA criteria, its capability to produce quality prostheses that were rated satisfactory more than 95% of the time after insertion and maintained this high rating at least for 1 year.

Adolescent↗

6-year clinical evaluation of fired ceramic inlays.

The purpose of the present study was to evaluate the quality of fired ceramic inlay restorations consisting of a feldspathic porcelain system (G-Cera Cosmotech II) after 6 years in vivo. A total of 49 fired ceramic inlays (for 27 premolars and 22 molars: class 1 in 11 teeth, class 2 in 36 teeth, and onlays in two teeth) were placed in 29 patients, and all restorations were evaluated at the time of placement, at 6 months, and 1, 2, 4, and 6 years after placement using modified USPHS criteria. Replicas made of the restorations were observed using a scanning electron microscope (SEM) to assess the state of the marginal area and wear of the restoration. Favorable color match was noted, and no bulk fracture, tooth fracture, or missing restorations were detected. Longevity was observed in 92% of the fired ceramic inlay restorations at 6 years (Kaplan-Meier method); however, marginal fracture was detected in six restorations (13%) and marginal discoloration in 11 (23%). SEM evaluation disclosed marginal microfracture in 49% of the restorations, wear in 19%, and wear of resin cement along margins in 36% at 6 years. No significant difference was observed in the incidence of each of these three characteristics between molars and premolars. This longitudinal 6-year clinical observation suggested that fired ceramic inlay restorations made by the G-Cera Cosmotech II system are aesthetic, durable, and clinically acceptable. Further follow-up is needed for the restorations showing marginal degradation and fracture from a microscopic and macroscopic perspective.

Dental Marginal Adaptation↗

Direct composite resin restorations: a review of some clinical procedures to achieve predictable results in posterior teeth.

UNLABELLED: The interest of patients in having tooth-colored restorations and the development of techniques and materials that make these restorations easier have contributed to make the esthetic restoration of posterior teeth popular. The direct use of composites in posterior teeth is a technique-sensitive procedure. Some difficulties, nevertheless, can be overcome or at least minimized by a heedful clinician by paying thorough attention to the various stages of the restorative technique. The present article seeks to review some concepts about this adhesive restorative procedure and to illustrate the possibilities of the technique with clinical reports. CLINICAL SIGNIFICANCE: The direct posterior composite restorative technique offers the possibility of closely matching the natural optical characteristics of the lost tooth structure. Aimed at showing the potential of this technique, this article presents two step-by-step case reports and also reviews some concepts related to these clinical procedures.

Adult↗

Evaluation of esthetic parameters of resin-modified glass-ionomer materials and a polyacid-modified resin composite in Class V cervical lesions.

OBJECTIVE: The purpose of this study was to compare the esthetics of 3 resin-modified glass-ionomer materials and 1 polyacid-modified resin composite to the esthetics of a conventional glass-ionomer control material. METHOD AND MATERIALS: One hundred eighty-seven Class V cervical restorations were observed clinically over 18 months. The esthetic index system that was used evaluated color match, translucency or opacity, and surface roughness. RESULTS: The tested materials behaved very dissimilarly and inconsistently. In general, the esthetic results of the resin-modified glass-ionomer materials and the polyacid-modified resin composite were far from optimal. The esthetic appearance of restorations seriously deteriorated during clinical service, mainly because of discoloration of margins, changes in translucency and opacity, and rapidly appearing roughness or dullness on the surface. Both the resin-modified glass-ionomer materials and the polyacid-modified resin composite evaluated in this study performed better esthetically than did the conventional glass-ionomer material. CONCLUSION: Indications for these combination materials are limited to areas where esthetics is not a primary concern but where their ease of application may guarantee a more durable functional result.

Acrylic Resins↗

The influence of porcelain layer thickness on the final shade of ceramic restorations.

STATEMENT OF PROBLEM: Ceramic restorations should be made of porcelain layers of different opacity, shade, and thickness in order to provide a natural appearance. By means of CAD/CAM layering technology such as CICERO, it is feasible to produce all-ceramic crowns with porcelain layers of predetermined thickness. However, it is not yet known whether changes in thickness of these porcelain layers within the clinically available space can perceivably influence the overall shade of the restoration. PURPOSE: The purpose of this study was to determine, quantitatively, the effect of different thickness ratios of opaque porcelain (OP) and translucent porcelain (TP) layers on the overall shade of all-ceramic specimens. MATERIAL AND METHODS: The CIELAB values of 5 assembled specimens, each consisting of 2 or 3 discs (CORE 0.70 mm/OP--0, 0.25, 0.50, 0.75, or 1.00 mm/TP 1.00, 0.75, 0.50, 0.25, or 0 mm) were determined with a spectrophotometer for the Vita shades A1, A2, and A3. Distilled water was used to attain optical contact between the layers. Black or white backgrounds were used to assess the influence of the background on the final shade. Color differences (DeltaE) between layered specimens were determined. Correlation between the thickness ratio and the L*, a*, and b* values was calculated by 2-tailed Spearman correlation analysis. RESULTS: The results indicated that small changes in OP/TP thickness ratio can perceivably influence the final shade of the layered specimens (DeltaE>1). Redness a* and yellowness b* increased with the thickness of OP for all shades. Redness a* (P<.01 for all shades) correlated more strongly with thickness than yellowness b* (P<.01 for A1 and A3; P<.05 for A2). The lightness (L*) was shade dependent. The correlation (r) between OP/TP thickness and L* was 0.975 (P<.01) for shade A1, 0.700 (not statistically significant) for shade A2, and 0.900 (P<.05) for shade A3. CONCLUSION: Small changes in thickness and shade of opaque and translucent porcelain layers can influence the final shade of the layered porcelain specimen.

Computer-Aided Design↗

A new shading concept based on natural tooth color applied to direct composite restorations.

OBJECTIVE: Patient demands have prompted manufacturers to improve intrinsic optical properties of resin composites and clinicians to refine application procedures. The aim of this study is to present a shading concept based on colorimetric L*a*b* and contrast ratio data of human dentin and enamel. METHOD AND MATERIALS: Extracted teeth of the A and B Vita shade groups (n = 8 per group) were sectioned according to 2 different planes to measure specific color (using the CIE L*a*b* system) and opacity (contrast ratio). Standardized samples of enamel and dentin shades of a new composite system (Miris, Coltène Whaledent) were submitted to the same colorimetric evaluation for comparison with natural tissues. RESULTS: Comparison of teeth from the Vita groups A and B having the same chroma showed limited variations regarding a* (green to red) and b* (blue to yellow) values; the only significant variation was the increasing b* values (yellow) with increasing chroma (A1 to A4 and B1 to B3). As for dentin contrast ratio, limited differences were reported, while enamel proved to increase in translucency with age (reduced contrast ratio). CONCLUSION: These data served as the foundation of the so-called natural layering concept, which makes use of 2 basic composite masses (dentin and enamel) that optically mimic natural tissues. This concept allows for simplified clinical application and layering of composite, as it uses only 1 universal dentin hue with several chroma levels and 3 enamel types for young, adult, and old patients, each exhibiting specific tints and translucency levels.

Acrylic Resins↗

Postoperative dental bleaching: effect of microleakage on Class V tooth colored restorative materials.

The effect of 3 percent, 11 percent, and 16 percent carbamide peroxide bleaching solutions and 35 percent hydrogen peroxide bleaching gel on microleakage of Class V composite resins, resin modified glass ionomer cements, and compomer restorative materials together with corresponding (if indicated) fourth/fifth generation bonding agents was evaluated using previously extracted human teeth. Five groups of Class V cavity preparations were placed in enamel of the facial surfaces of 200 teeth. Groups A through D included 40 restorations each (4 different restorative materials and their accompanying bonding agent multiplied by 10 teeth) treated with 3 percent, 11 percent, and 16 percent carbamide peroxide bleach and 35 percent hydrogen peroxide bleach. Group E included 40 restorations without treatment of bleach and stood as the control. The restorative materials included were: Fuji II LC resin modified glass ionomer cement, Helioprogress composite resin/-Heliobond adhesive system, Aelitefil composite resin/Allbond 2 adhesive and Dyract compomer material/Prime & Bond adhesive system. Bleaching agents included were Rembrandt 3 percent peroxide gel, Perfecta 16 percent carbamide peroxide gel, White & Brite 11 percent carbamide peroxide solution and Superoxyl 35 percent hydrogen peroxide gel. All teeth were thermally stressed for 100 cycles and microleakage were assessed by dye penetration. The results were tabulated using Analysis of Variance (ANOVA) testing procedures. The Aelitefil composite resin material behaved the least favorably (relative to microleakage) compared to the other materials when exposed to various concentrations of dental bleaching agents.

Analysis of Variance↗

The oral pigmentation chart: a clinical adjunct for oral pigmentation in removable prostheses.

PURPOSE: Non-Caucasian patients exhibit different characteristics of oral pigmentation and may request that the acrylic resin parts of their dentures look natural, simulating the original mucosal color. Tooth loss, bone resorption, and lack of attached gingiva may, however, make it difficult to determine what the original pigmentation was like. The purpose of this investigation was to study the distribution in oral pigmentation around the natural dentition in non-Caucasians, in a preliminary effort to classify these variations into a chart of oral pigmentation, and to analyze its reproducibility. MATERIALS AND METHODS: For the study, 106 dentate non-Caucasians were selected from two universities: ACTA (patient group) and UCLA (nonpatient group). A pigmentation scheme was devised on the basis of half of the participants, and the others were divided into categories by four observers independently. Cohen's kappa was then calculated. RESULTS: On the basis of information obtained from the ACTA participants, six categories of mucosal pigmentation were defined. The kappa statistics for the four observers varied from .58 to .79 for intraobserver agreement and from .15 to .55 for interobserver agreement. CONCLUSION: The Oral Pigmentation Chart is a simple device that makes it possible to simulate oral pigmentation in the acrylic resin parts of removable dentures. The reproducibility appeared to be acceptable when clinician and dental technician were calibrated. Patients can be offered a choice of the kind of pigmentation geography they want in their removable prostheses.

Acrylic Resins↗

Does the end-to-end venous anastomosis offer a functional advantage over the end-to-side venous anastomosis in high-output arteriovenous grafts?

This study explores the hemodynamics, mechanics, and biologic response of end-to-end versus end-to-side venous anastomoses in a canine arteriovenous graft model. Femoral polytetrafluoroethylene grafts were implanted bilaterally in a paired fashion (n = 22). Detailed local hemodynamic measurements were made by use of color Doppler ultrasound imaging at 1, 4, 8, and 12 weeks after implant. Measurements included volumetric flow rate and Doppler-derived spectral window (percent window) as a measure of turbulence. Amplitude and velocity of vessel wall movement were also measured. Volume of perivascular tissue vibration quantitated kinetic energy transfer through the vessel wall. Volumetric flow rate (end to end, 1013 +/- 70 ml/min; end to side, 1015 +/- 72 ml/min), percent window (end to end, 6.6% +/- 0.6%, end to side, 5.6% +/- 0.4%) and volume of perivascular tissue vibration (end to end, 19.6 +/- 1.2 ml, end to side, 16.3 +/- 1.8 ml) were statistically equivalent in the two graft types (end to end vs end to side p greater than 0.05). Both graft types developed venous intimal-medial thickening of a similar magnitude: end to end, 0.35 +/- 0.05 mm, end to side, 0.43 +/- 0.09 mm, normal vein 0.070 +/- 0.004 mm (analysis of variance [ANOVA] p less than 0.001, p less than 0.01 for end to end or end to side vs control, end to end vs end to side p greater than 0.05 by Student-Newman-Keuls test). The best correlations with venous intimal-medial thickening were obtained from inverse percent window (r = 0.84, p less than 0.001) and volume of perivascular tissue vibration (r = 0.68, p less than 0.001). In the end to end configuration the relative amplitude of venous wall movement decreased, and the relative velocity of wall motion increased over time. We conclude that in the circumstances of this high flow arteriovenous graft model the end-to-end venous anastomosis does not significantly differ from the end-to-side venous anastomosis in terms of flow stability, turbulence, or kinetic energy transfer. The magnitude of the hyperplastic response is statistically equivalent for the two anastomotic types, but the pattern is somewhat different, possibly providing evidence for differences in stress distribution. Differences in the relative amplitude and velocity of vessel wall movement suggest that anastomotic geometry may affect the way in which kinetic energy is dissipated at the graft/vessel interface.

Animals↗

Influence of salivary organic substances on the discoloration of esthetic dental materials-a review.

The objective of this article was to review the articles on the interaction of salivary organic substances with resin-based dental materials and on the interaction of these organic substances with exogenous chemical agents, which results in discoloration. Original scientific articles or reviews on the saliva, acquired pellicle, and the interaction with pellicle and chemical agents related to dental resin-based materials were reviewed. Salivary esterases can increase or decrease the internal and external discoloration. The formation of acquired pellicle on the surface of a material varies by the properties of material, and the pellicle interacts with denaturation agents, such as tannin and chlorhexidine, to form stains and also adsorbs staining substances. Therefore, for the quality and longevity of restorations, protocols for the evaluation of the influence of organic substances on the extrinsic staining of restorative materials should be included in the evaluation of aesthetic restorative materials.

Dental Materials↗

The value of examination aids in victim identification: a retrospective study of an airplane crash in Nepal in 2002.

After the crash of an airplane in Nepal in the year 2002, the dental status of the 14 European victims was examined at autopsy as well as after additional removal of the soft tissue and compared with antemortem findings which were available in 11 cases. Re-examination of all jaws showed that nine composite fillings and seven root fillings as well as one parapulpal pin could not be detected during autopsy. Because tooth-coloured restorations may be overseen even by an experienced expert, the findings underline the necessity of performing a full resection of both jaws and removal of the soft tissue. Furthermore, X-ray analysis of the jaws and the use of phosphoric acid or ultra violet radiation for recognizing tooth-coloured restorations are recommended.

Accidents, Aviation↗

Phakic implantation of a black intraocular lens in a blind eye with leukocoria.

A 54-year-old woman with leukocoria from a white cataract requested evaluation for the undesired cosmetic appearance of her blind right eye. The eye was hypotonous from chronic total retinal detachment, and the lens appeared loose and partially resorbed. A solid, black poly(methyl methacrylate) intraocular prosthesis was placed in the phakic posterior chamber and sutured into the ciliary sulcus, leaving the lens undisturbed. The patient achieved excellent cosmesis and a significant improvement in self-image.

Blindness↗

Clinical evaluation of an anterior hybrid composite resin over 8 years.

AIM: To evaluate the performance of an anterior hybrid composite resin restorative material (Opalux). DESIGN: Single-centre clinical trial. MATERIALS AND METHODS: Scores were obtained based on USPHS criteria for marginal adaptation, anatomic form, colour match, surface roughness and marginal discolouration. INTERVENTIONS: The restorative material was evaluated in suitable cavities in 24 patients (12 male, 12 female). Ethical permission and consent were obtained. MAIN OUTCOME MEASURES: Baseline data was collected on 44 restorations (25 Class III, 3 Class IV, 16 Class V) and reviewed independently by two of the three clinicians who contributed to the study who then reached a consensus score. Restorations were reviewed and scored in the same way at 3 months and 1, 2, 3 and 8 years. RESULTS: The total number of alpha ratings at baseline and review (3 months and 1, 2, 3 and 8 years) appointments for the following parameters were: marginal adaptation (33, 28, 29, 27, 12, 17), anatomic form (39, 30, 32, 26, 17, 15), surface roughness (34, 26, 24, 23, 11, 4), colour match (24, 25, 26, 24, 15, 12) and marginal discolouration (39, 31, 30, 25, 10, 9). The incidence of secondary caries was very low. Life table analysis suggests a 73% survival, with no scores below B, at 8 years. CONCLUSIONS: The majority of these restorations continued to perform satisfactorily. Although this particular material is no longer available, these results may be applicable to currently available similar materials.

Adolescent↗