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Histologic evaluation of a human immediately loaded titanium implant with a porous anodized surface.

BACKGROUND: Several researchers have demonstrated, in the past decade, in clinical and histologic studies, that immediate loading can be successfully used in implant dentistry. Many factors are thought to be of importance in obtaining mineralized tissues at the interface. One of these factors is the implant surface characteristics. Recently, an implant with a new porous anodized surface has been introduced in the market. PURPOSE: The goal of this study was to histologically evaluate a clinically retrieved immediately loaded implant with a porous anodized surface. MATERIALS AND METHODS: After a 6-month loading period, an immediately loaded implant with a porous anodized surface that had been inserted in the posterior maxilla was retrieved. RESULTS: Histology showed that mineralized tissue was present at the interface and the bone-implant contact percentage was about 60%. No gaps or fibrous tissue or inflammatory infiltrate were present at the interface. CONCLUSIONS: Results show that immediate loading of dental implants has no untoward effects on the formation of mineralized tissues at the interface. Immediate loading is a possible alternative in implant dentistry. key words: dental implants, histology, immediate loading, oxide coating, porous surface

Benzenesulfonates↗

Color measurements as quality criteria for clinical shade matching of porcelain crowns.

STATEMENT OF PROBLEM: The ability of a dentist to select and communicate an acceptable shade match to a dental laboratory may be the most important factor in esthetic restorative dentistry. PURPOSE: The purpose of this study was to evaluate the use of instrumental color measurement in clinical shade matching of porcelain-fused-to-metal (PFM) and all-porcelain crowns. The relative effects of clinical and laboratory factors related to shade matching for PFM and all-porcelain crowns were also evaluated. MATERIALS AND METHOD: Forty patients treatment planned to receive PFM or all-porcelain crowns made up the study population. The patients were randomly divided into two groups for shade selection: conventional visual assessment and photocolorimetric analysis. At the preparation appointment, a photograph was taken of the target tooth along with four shade guide tabs selected by the two visual observers. The crown was fabricated by either visual selection or by the lowest E* values determined from the photographs and a spectrophotometer. The same dental laboratory fabricated all 40 restorations. At the cementation appointment, clinical criteria were used to evaluate anatomy/contour, surface texture, and the amount of glaze as it relates to color perception before the restoration was cemented. RESULTS: The mean E* between the reference tooth before preparation and the crown before cementation in the visual assessment group was 10.49 (+/- 14.6), whereas the mean E* in the photocolorimetric group was 8.99 (+/- 5.7). Analysis of data showed that the observers and the colorimetric technique were perfect (E* = 0) 41% of the time and varied (E* = 0.1 or higher) 59% of the time. Data collected further showed no significant difference or correlation between shade selection methods and the evaluated clinical criteria. CONCLUSIONS: These results provide evidence that there is no significant difference in shade selection using the conventional visual assessment by two experienced clinicians or the photocolorimetric technique. CLINICAL SIGNIFICANCE: The use of photocolorimetric analysis in shade selection can serve as a reliable alternative to conventional visual shade selection. This method is useful for clinicians who have difficulty with shade selection.

Color↗

Priapism in sickle cell disease: the case for early implantation of the penile prosthesis.

OBJECTIVES: Recurrent ischemic priapism in sickle cell (SS) patients often leads to impotence. Blockage of venous outflow by sickle cells leads to anoxia of the cavernosal smooth muscle with subsequent replacement of the erectile tissue with dense fibrosis. This study evaluates the efficacy of early penile prosthesis implantation in patients with priapism associated with sickle cells disease. METHODS: Our recent experience includes 6 SS patients with impotence resulting from repeated episodes of priapism and 1 SS patient who suffered penile autoamputation from prolonged tricorporeal low flow priapism. The average age was 26 years. Six patients underwent excision of fibrotic cavernosal sinusoidal tissue and placement of a malleable prosthesis. The autoamputation case was managed with a one-stage penile reconstruction using a forearm free-flap and a two-piece inflatable penile prosthesis. RESULTS: All patients in our series are currently potent. Because of infection, 1 patient required removal and subsequent reinsertion of his prosthesis, and another has required revision. CONCLUSION: Potency in the young SS patient with recurrent episodes of ischemic priapism may best be managed by a penile prosthesis. Early implantation may lessen the psychological trauma of repeated priapisms, and reduce the technical difficulties and complications associated with penile prosthetic insertion in the presence of dense fibrosis.

Adolescent↗

Stain resistance of maxillofacial materials.

The resistance of three silicone and one polyvinyl chloride maxillofacial materials to staining by tea, lipstick, and disclosing solution was measured by reflectance spectrophotometry. Changes in color caused by staining were larger than changes caused by color instability of the base elastomers or pigments under conditions of accelerated aging.

Color↗

Analysis of edge-losses in reflectance measurements of pigmented maxillofacial elastomer.

Edge-losses occur during reflectance measurements of pigmented maxillofacial elastomer when light is scattered within a sample beyond that part of the surface exposed to the observation system of the optical device. A custom sample-holder is presented which redirects light that would not be measured during conventional reflectance measurement back into the sample. The amount of edge-loss occurring within thin layers of maxillofacial elastomer with tan pigment on black-and-white backings was found to depend on sample thickness, the backing, the beam size used during conventional reflectance measurement, and the optical term bS = (2KS + K2)1/2. Data analysis revealed a significant interaction among these four factors. Additionally, the edge-loss occurring during the tristimulus reflectance measurement of thick samples of maxillofacial elastomer with various concentrations of tan and black pigment was found to be linearly related to bS up to a limiting value, with no additional edge-loss occurring for bS values above this limiting value. Edge-loss is an important consideration during the matching of the optical characteristics of pigmented maxillofacial material to those of human skin.

Absorption↗

Histologic evaluation of an immediately loaded titanium implant retrieved from a human after 6 months in function.

Clinical and histologic studies have demonstrated that immediate loading can be successfully used in implant dentistry. Many factors are thought to be of importance in obtaining mineralized tissues at the interface. This study describes the implant interface of an immediately loaded implant with a conical implant-abutment connection that had been inserted in the posterior mandible for 6 months. Histology showed that mineralized tissue was present at about 74% +/- 6% of the implant interface. No gaps, fibrous tissue, or inflammatory infiltrate were present at the interface. The bone adjacent to the implant was mainly lamellar (90% +/- 4.5%). Tetracycline was used to label trabecular bone, and labeled bone was found in direct contact with the implant surface. The extensive labelling by tetracycline demonstrated a large quantity of newly formed bone at the implant interface. The distance between the 2 lines marked by tetracycline was 85 +/- 5 mm. The results of this study show that immediately loaded dental implants can form mineralized tissues at the bone-implant interface.

Aged↗

Bone response to machined and resorbable blast material titanium implants: an experimental study in rabbits.

The aim of the present study was a comparison of implants' responses to a machined surface and to a surface sandblasted with hydroxyapatite (HA) particles (resorbable blast material [RBM]). Threaded machined and RBM, grade 3, commercially pure, titanium, screw-shaped inplants were used in this study. Twenty-four New Zealand white mature male rabbits were used. The inplants were inserted into the articular femoral knee joint according to a previously described technique. Each rabbit received 2 inplants, 1 test (RBM) and 1 control (machined). A total of 48 implants (24 control and 24 test) were inserted. The rabbits were anesthetized with intramuscular injections of fluanisone (0.7 mg/ kg body weight) and diazepam (1.5 mg/kg b.wt.), and local anesthesia was given using 1 mL of 2% lidocaine/adrenalin solution. Two rabbits died in the postoperative course. Four animals were euthanatized with an overdose of intravenous pentobarbital after 1, 2, 3, and 4 weeks; 6 rabbits were euthanatized after 8 weeks. A total of 44 implants were retrieved. The specimens were processed with the Precise 1 Automated System to obtain thin ground sections. A total of 3 slides were obtained for each implant. The slides were stained with acid and basic fuchsin and toluidine blue. The slides were observed in normal transmitted light under a Leitz Laborlux microscope, and histomorphometric analysis was performed. With the machined implants, it was possible to observe the presence of bone trabeculae near the implant surface at low magnification. At higher magnification many actively secreting alkaline phosphatasepositive (ALP+) osteoblasts were observed. In many areas, a not yet mineralized matrix was present. After 4 to 8 weeks, mature bone appeared in direct contact with the implant surface, but in many areas a not yet mineralized osteoid matrix was interposed between the mineralized bone and implant surface. In the RBM implants, many ALP+ osteoblasts were present and in direct contact with the implant surface. In other areas of the implant perimeter it was possible to observe the formation of an osteoid matrix directly on the implant surface. Mature bone with few marrow spaces was present after 4 to 8 weeks. Beginning in the third week, a statistically significant difference (P < .001) was found in the bone-implant contact percentages in machined and RBM implants. It must be stressed that these results have been obtained in a passive, nonloaded situation.

Alkaline Phosphatase↗

Limitations and discrepancies of transthoracic and transoesophageal echocardiography compared with surgical findings in patients submitted to surgery for complications of infective endocarditis.

OBJECTIVE: Transoesophageal echocardiography (TEE) is recognized to be superior to transthoracic echocardiography (TTE) in evaluating complications of infective endocarditis (IE). The aim of this study was to compare results from TTE and TEE with surgical findings, and to assess limitations and discrepancies of TEE as compared with surgical findings. METHODS: A retrospective analysis was carried out in 63 consecutive patients undergoing surgical intervention for IE-related complications. All patients were submitted to TTE and TEE before surgery. Clinical, anaesthesiological and surgical data were reviewed for all patients as well as the TTE and TEE examinations recorded on S-VHS videotape. Patients were divided into two groups according to the time elapsed from TEE to surgery (> 72 h in group A and < 72 h in group B). RESULTS: The study population included 44 patients with native valve endocarditis and 19 patients with prosthetic valve endocarditis for a total of 76 affected valves (54 native and 22 prosthetic valves). No significant differences were observed between groups in number of patients (31 vs. 32; P = NS), of native valves (29 vs. 27; P = NS), and of prosthetic valves (10 vs. 12; P = NS). Discrepancies between TEE and surgical findings were found in 14 cases (11/31 in group A vs. 3/32 in group B; P = 0.01). CONCLUSIONS: Time between TEE and surgery seems to be an important factor affecting comparison. Lesion characteristics appear to be more precise and concordant with surgical findings the shorter the time elapsed from TEE to surgery. Changes resulting from disease progression require repeat TEE evaluation prior to surgical intervention for IE-related complications. This could be useful in providing the surgeon with a more accurate definition of valvular lesions for optimal planning of intervention.

Abscess↗

Does the quality of advanced prosthetic dentistry determine patient satisfaction?

In a clinical follow-up study 42 patients were selected from an original sample of 335 individuals who had undergone extensive prosthetic treatment. The selection was done in accordance with a treatment satisfaction measure. The selected patients' appliances were classified in accordance with the California Dental Association (CDA) quality assessment system. Altogether, most of the new reconstructions were rated as satisfactory. The removable partial dentures had a somewhat higher share of non-acceptable appliances according to the CDA criteria. There was an association between the CDA categories and patient satisfaction. Using logistic regression analysis and knowing the CDA rating, we could correctly classify 67% of the patients with regard to the satisfaction measure. The satisfaction measure was modified on the basis of an interview, improving the model to 83% correctly classified. It was concluded that the technical quality of the prosthodontic treatment was associated with patient satisfaction.

Attitude to Health↗

Optical properties of paint-on resins for shade modification of crown and bridge resins--light transmittance characteristics--.

The purpose of this study was to examine the light transmittance characteristics of the paint-on resins for shade modification. Three shades of paint-on resin, one crown and bridge resin, and human enamel were used. Specimens with four different thicknesses (75-150 microm) were prepared. The light transmittances including its wavelength distribution and diffusion characteristics were measured. The color values and the color differences among thicknesses of specimens were also determined. The light transmittance values of the paint-on resins ranged from 60.3% to 88.3% at 100 microm thickness, which were lower or nearly equal in comparison with the crown and bridge resin and enamel. Although differences in the wavelength distribution of transmittance among materials were found at lower wavelengths, all materials showed similar diffusion characteristics. The thin layer of paint-on resin effectively changed the color of restorative resin. The paint-on resin may be an effective material for the modification of the color appearance matching required.

Color↗

The Ross procedure in children under ten years of age.

BACKGROUND AND AIMS OF THE STUDY: The potential advantages of the Ross procedure in children under 10 years of age have yet to be validated. Concerns remain regarding progressive dilatation of the pulmonary autograft and potential homograft stenosis. We present our experience in this age population. METHODS: A retrospective analysis of aortic root replacement using the Ross procedure in 11 young children (nine males, two females; median age 84 months; range 3 months to 10 years) between January 1996 and January 1999 was performed jointly in two pediatric surgical centers. RESULTS: There were no operative deaths. Mean hospital stay was 12 +/- 4 days, and mean follow up 14.5 +/- 8 months. The event-free survival (death, reoperation, endocarditis, arrhythmia) was 100%. Currently, nine children are in NYHA functional class I, and two in class II. The autograft and homograft were evaluated by serial echocardiography. There was no sign of progressive dilatation of the autograft. Aortic regurgitation was trivial in four children and mild in seven. No growth of the autograft was noted; this was consistent with minimal somatic growth. Homograft peak gradients remained low during the follow up. CONCLUSIONS: Although the pulmonary autograft procedure is more complex than other types of aortic valve replacement, it can be safely applied in children. Early follow up indicates satisfactory performance of the autograft. If dilatation will not occur, pulmonary root autograft may be an attractive substitute for diseased aortic valves in children.

Aortic Valve↗

Shades of a color. Illusion or reality?

Attaining the highest clinical level in esthetic and cosmetic dentistry necessitates the development of artistic skills; of balancing illusion with reality. The shade of a tooth is a combination of color and light and varies in different light conditions. Understanding the differences in color shades is the basis to creating illusions. Understanding light and color, and the reality of illusions, allows the clinician to design and sculpt a smile, to modify a flawed display artistically so that patients may perceive it as natural and more attractive, and to design laminates and veneers, class III, class IV, and cervical cavities.

Color↗

Three-dimensional shade analysis: perspectives of color--Part II.

In addition to outlining the fundamental principles of color and its qualitative and quantitative measurement, the first part of this article explained the chemical, physical, physiological, and psychological realization of color. To complete this discussion, the second part focuses on numerous variables that affect shade determination in the clinical chromatic environment. A contemporary shade selection system is also presented, and its systematic approach and limitations when utilized in a laboratory or clinical environment are detailed.

Adult↗

Influence of posts and cores on light transmission through different all-ceramic crowns: spectrophotometric and clinical evaluation.

PURPOSE: The influence of different types of posts and cores on light transmission through all-ceramic crowns was assessed by spectrophotometric analysis and clinical evaluation. MATERIALS AND METHODS: Three extracted natural teeth were replicated in acrylic resin, with roots prepared to receive standardized posts and cores. Using a silicone impression material as a template, various prosthodontic reconstructions were obtained by combining four types of posts and cores (polished and matte-finished gold alloy, all-ceramic, and ceramized metal alloy) and three types of all-ceramic crowns (IPS-Empress 2 surface-colored, IPS-Empress 2 stratified, and In-Ceram). The spectrophotometric analysis was performed in the dark at 25 degrees C. The teeth were backlit with an incandescent lamp at the color temperature of A illuminant and shielded to avoid spurious light entering the spectrophotometer. The transmitted light was analyzed in terms of luminance at four points of the sample surface (cervical, middle, incisal, and proximal). Twelve measurements were performed for the natural teeth, and 144 were performed for the artificial teeth. RESULTS: Natural teeth had the highest luminance. Among all-ceramic crowns, surface-colored IPS-Empress 2 had the highest luminance, and stratified IPS-Empress 2 had the lowest. Regarding posts and cores, the luminance was highest with the all ceramic, lower with the ceramized and the polished gold alloy (which had very similar luminance), and lowest with the matte-finished gold alloy. No significant difference among prosthodontic combinations was detected under clinical observation. CONCLUSION: The surface-colored glass ceramic (IPS-Empress 2) was the most translucent crown. At the standard crown thickness used, there were small, significant spectrophotometric, but not clinical, differences among the combinations tested. These findings show no esthetic contraindications for the use of polished gold alloy posts and cores with all-ceramic crowns.

Acrylic Resins↗

Histomorphometric analysis of the bone-implant contact obtained with 4 different implant surface treatments placed side by side in the dog mandible.

PURPOSE: The different implant systems available today present several types of surface treatment, with the aim of optimization of bone-implant contact. This study compared 4 different types of implant surfaces. MATERIALS AND METHODS: The first, second, third, and fourth mandibular premolars were extracted from 5 young adult mongrel male dogs. Ninety days after removal, four 3.75-mm-diameter, 10-mm-long screw-type implants (Paragon) were placed with different surface treatments in mandibular hemiarches. The dogs received 2 implants of each of the following surface treatments: smooth (machined), titanium plasma spray (TPS), hydroxyapatite coating (HA), and sandblasting with soluble particles (SBM). The implants were maintained unloaded for 90 days. After this period, the animals were sacrificed, and the hemimandibles were extracted and histologically processed to obtain non-decalcified sections. Two longitudinal ground sections were made for each implant and analyzed under light microscopy coupled to a computerized system for histomorphometry. RESULTS: The following means were obtained for bone-implant contact percentage: machined = 41.7%, TPS = 48.9%, HA = 57.9%, and SBM = 68.5%. DISCUSSION: The means for all treatments that added roughness to the implant surface were numerically superior to the mean found for the machined surface. However, this difference was statistically significant only between groups SBM and machined (Tukey test, P < .05). CONCLUSIONS: The SBM-treated surface provided a greater bone-implant contact than a machined surface after 90 days without loading in this model.

Analysis of Variance↗