Dyes for caries detection influence sound dentin bond strength

This study evaluated the influence of caries-detection dyes on the in vitro tensile bond strength of adhesive materials to sound dentin. Caries-free human molars were ground to expose superficial dentin. Two dyes (a commercial 0.5% basic fuchsin in propylene glycol and Cari-D-Tect) were applied to sound dentin and rinsed. Subsequently, the dentin was etched with phosphoric acid (35%) and rinsed, leaving a moist dentin surface. The adhesive (Prime & Bond 2.0) was applied in two layers and light cured. A composite (TPH Spectrum), a compomer (Dyract), and a hybrid ionomer (Advance) were used to prepare the bond-strength specimens with a 3-mm-in-diameter bonding area. Control groups were made without use of dyes. Six specimens were prepared for each group. After 24 hours in distilled water, tensile bond strength (MPa) was measured using a testing machine. Analysis of variance was used to evaluate the data. Without dyes, bond strengths of TPH Spectrum and Dyract with Prime and Bond 2.0 were similar and both values were significantly (P < 0.05) higher than that of Advance with Prime & Bond 2.0. Dyes for caries detection reduced the bond strength of TPH Spectrum and Dyract but not Advance when used with Prime and Bond 2.0.

Comparison of bond strengths of three denture base resins to treated nickel-chromium-beryllium alloy

PURPOSE

In-vitro bond strengths of 3 denture base resins (Trutone, Lucitone 199, and Triad) to a nickel-chromium-beryllium removable partial denture alloy (Ticonium) were tested with 3 surface pretreatments: sandblast, acid etch, and Rocatec (silica blasting), with or without primers (Dentsply, CR inlay cement, and Super Bond).

MATERIAL AND METHODS

Lucitone 199 denture base resin bonded to the nonprimed sandblasted alloy specimen served as the control group. Alloy specimens were prepared, surface treated, and primed or not primed with primer. The treated specimens were then packed and processed with the denture base resin. Bonded specimens were stored in the distilled water at 37 degrees C for 24 hours, and then debonded in tension. The force at which the bond failed was noted, and bond strength was calculated in megapascals (MPa). Five replications for each condition (180 specimens total) were tested.

RESULTS

Significant differences in bond strength were observed with primer, the most important factor, followed by pretreatment and denture base resin. Without primer for all 3 denture base resins, the Met-Etch and Rocatec treated group showed significantly higher bond strengths than the sandblasted groups. For Trutone denture base resin, nonprimed treated groups produced significantly higher bond strength than those for the other 2 denture base resin, nonprimed treated groups produced significantly higher bond strength than those for the other 2 denture base resins. The control group had zero bond strength. For Dentsply primer, the Rocatec treated group bonded to Lucitone 199 resin produced the highest bond strength value (14.8 +/- 1.8 MPa). For CR inlay cement, the Met-Etch and Rocatec treated groups for Lucitone denture base resin demonstrated the highest bond strength (19.3 +/- 4.8 MPa, and 19.3 +/- 1.8 MPa, respectively). For super Bond primer, the Met-Etch treated group for Trutone resin demonstrated the highest bond strength (19.8 +/- 6.2 MPa).

CONCLUSIONS

Without primer, the control had the lowest bond strength (0 MPa), and the Trutone groups showed the highest bond strength (11.7 +/- 4.1 MPa). Met-Etch and Rocatec treated groups produced higher bond strengths than the sandblasted groups. The primed specimens demonstrated significantly higher bond strengths than nonprimed specimens, except for Trutone resin, for which primed specimens produced lower bond strengths than the nonprimed specimens.

Bond strength between cements and metals used for endodontic posts

OBJECTIVES

Adhesive cements used with metal endodontic posts may decrease fracture in non-vital teeth. Results from studies that evaluate cements for post retention by pulling posts out of extracted teeth are difficult to interpret owing to the number of interfaces where fracture might occur. The objective of this study was to isolate the metal/cement interface for tensile bond strength testing and microscopic observation.

METHODS

Three metals and seven cement treatments were examined for bond strength by using a truncated cone tensile test. The bond strength data were analyzed by a two-way ANOVA and Scheffé's multiple comparison test at p = 0.05. Specimens were examined at 50x magnification to determine the failure mode and with scanning electron microscopy (500x) to observe the surfaces after debonding.

RESULTS

Significant differences in tensile bond strengths were found among cements compared within two of the metal groups. One of the metal groups had no significant differences among cement bonds. When comparing within cement treatment groups, two groups had significant differences in bond strength among the metals. Microscopic observations revealed adhesive, cohesive and mixed failure modes that varied with cement treatment and metal combination. The interaction between metal and cement was a critical determinant of the strength and characteristic fracture mode of the bond achieved.

SIGNIFICANCE

Some of the cement treatments performed better (i.e., higher bond strength) with some metals than with others. Other cements had similar bond strengths with all three metals. Because of this interaction, careful consideration of the materials combination should help to maximize the bond at the metal/cement interface.

Bond strength to dentin with artificial carious lesions: influence of caries detecting dye

PURPOSE

To evaluate the influence of dyes for caries detection on tensile bond strength of adhesive materials to artificial carious dentin.

MATERIALS AND METHODS

Buccal and lingual enamel of human molars were removed leaving intact dentin surfaces. The entire surface of each specimen was covered with nail varnish, keeping a window area of 4 x 4 mm. Artificial carious lesions were induced with acidified gel. Three dyes (0.5% basic fuchsin; Caries Finder and Cari-D-Tect) were used according to manufacturers' recommendations. Specimens were etched with 35% phosphoric acid for 20 s, washed and dried, leaving a wet dentin surface. The adhesive system (Prime & Bond 2.0) was applied in two layers and light-cured. Restorative materials (TPH Spectrum, Dyract, Advance) were bonded using a 3-mm diameter inverted-cone mold. Control groups were made without dye. Eight samples were tested for each group. After 24 hrs of storage in distilled water, the samples were debonded using a testing machine at 0.5 mm/min crosshead speed.

RESULTS

ANOVA and Tukey-Kramer test showed that TPH Spectrum (0.73 MPa) and Dyract (0.74 MPa) had similar bond strengths, and both were higher than Advance (0.0 MPa), which was statistically different (P < 0.01). The use of the dyes did not cause any changes in tensile bond strength for any tested materials.

X-linked female band heterotopia-male lissencephaly syndrome

We report a family with band heterotopia in a mother and daughter and lissencephaly in a son (X-linked inheritance pattern). Postmortem examination of the boy revealed classical lissencephaly and, among other findings, simplified and discontinuous inferior olives without inferior olivary heterotopia. The absence of inferior olivary heterotopia may distinguish X-linked lissencephaly from other conditions with classic lissencephaly such as Miller-Dieker syndrome.

Effectiveness of adhesive systems for a Co-Cr removable partial denture alloy

PURPOSE

In vitro bond strengths of traditional denture base acrylic resin (Lucitone 199) to a cobalt-chromium partial denture alloy (J.D. Partial Denture Alloy) were tested using two surface pretreatments (sandblast, sandblast and electrochemical etch) with three adhesive primers: Lee Metal Primer, Acrylic Solder, and CR Inlay cement. A sandblasted group with no primer served as the control.

MATERIALS AND METHODS

The alloy specimens (8.0-mm bonding diameter) were cast and invested to receive a traditional denture base resin after surface treatments (sandblasted, and sandblasted-electrochemically etched) and application of adhesive primers. The bonded specimens were stored in distilled water at 37 degrees C for 24 hours and divided into two groups. The first group was debonded in tension on a testing machine at a cross-head speed of 0.05 cm/min. The second group was subjected to thermocycling of 1,000 cycles and then tested for tensile bond strength. The force at which the bond failed was recorded, and the bond strength was calculated in megapascals (MPa). The sites of bond failure were examined, quantified under (20x) magnification, and recorded. Ten specimens were evaluated for each experimental condition for a total of 160 specimens. Data were analyzed by ANOVA with a factorial design. Means were compared by Tukey intervals at the 0.05 significance level.

RESULTS

Significant differences in bond strength were observed, with primers being the most important factor, followed by pretreatment and storage and thermocycling with significant interactions. Sandblasted-electrochemically etched alloy with primers more effectively enhanced bond strength of the denture base resin to the treated alloy than sandblasted alloy with primers. Thermocycling had a greater effect on bond strength of the specimens with Acrylic Solder when compared with Lee and CR Inlay primers. The highest bond strengths (> or = 18.0 MPa) were observed for the conditions involving electrochemical etching and the priming with CR Inlay cement (both after 24 hours and thermocycling of 1,000 cycles). For primed specimens, the bond failures occurred cohesively within the primers or the denture resin and adhesively between the primers and the denture base resin, or between primers and alloy. For nonprimed, the bond failures occurred adhesively at the denture base resin-metal interface.

CONCLUSIONS

Nonprimed specimens (both sandblasted and electrochemically etched) had lowest bond strength (0.4 +/- 0.1 MPa; 0.3 +/- 0.4 MPa). The bond strengths of the primed treated specimens were improved significantly. The CR Inlay-treated specimens exhibited the highest bond strength (20.6 +/- 6.3 MPa). After thermocycling for 1,000 cycles, the bond strengths of the specimens were significantly lower than the bond strengths of the specimens after 24 hours.

Discoloration of a compomer by stains

This study evaluated the color stability of a polyacid-modified composite (compomer) upon exposure to stains. Five disks were prepared for immersion in each of five stains: coffee, chlorhexidine, cola, red wine, and water as a control. Color measurements were made on a reflection spectrophotometer at baseline, after 24-hour incubation, and after 24, 48, and 72 hour immersion in each stain. At 24 hours, perceptible color changes occurred for specimens in red wine and coffee. After 48 hours, perceptible color changes occurred for specimens in cola. Chlorhexidine and water caused no perceptible color changes. A compomer is susceptible to staining by coffee, red wine, and cola.

Tensile bond strength of porcelain teeth to denture resin before and after aging

PURPOSE

This in vitro study compared the effects of four surface treatments on the bond strength between porcelain denture teeth and heat-polymerized denture base acrylic with and without a ceramic primer and bonding agent and after three storage conditions.

MATERIALS AND METHODS

Polished porcelain specimens (120) were divided into 24 groups of five each as follows: surface treatments (none, etched, sandblasted, and air abraded), ceramic primer and bonding agent (yes and no), and storage conditions (water storage, thermocycling, and accelerated aging). All the specimens were tested to failure in tension on a testing machine.

RESULTS

Hydrofluoric acid etching, sandblasting, and air abrasion did not improve the bond strength of specimens without ceramic primer and bonding agent compared to those polished with 600-grit silicon carbide paper. Use of ceramic primer and light-activated bonding agent (Scotchbond MP) increased the bond strength. For thermocycled specimens treated with ceramic primer and bonding agent, the bond strengths ranged from 10 to 31 MPa in the following order: air abraded = etched < no treatment < sandblasted.

CONCLUSIONS

Ceramic primer and bonding agent dramatically improved the bond strength of porcelain teeth to heat-polymerized denture resin. Sandblasting improved bond strength of bonded samples compared to those that were etched or polished only.

Comparison of bond strengths of denture base resins to nickel-chromium-beryllium removable partial denture alloy

PURPOSE

In vitro bond strengths of a traditional denture base resin (Lucitone 199) and three adhesive denture base resins (Meta-Dent, Meta-Fast with liner, and Meta-Fast without liner) to treated nickel-chromium-beryllium (Ni-Cr-Be) partial denture alloy were tested with four alloy surface pretreatments (sandblast, Met-etch, Rocatec with silane, and Rocatec without silane), with or without primer (Dentsply). The Lucitone 199 resin bonded to the nonprimed sandblasted group was the control group. The hypothesis was the use of alloy pretreatments and/or primer does not improve the bond strength of denture base resins to sandblasted Ni-Cr-Be partial denture alloy.

MATERIAL AND METHODS

Primed and nonprimed bonded specimens were prepared and finished, stored in 37 degrees C distilled water for 24 hours, then debonded in tension on a testing machine. The bond strength was calculated in megapascals (MPa). Five specimens were prepared and tested for each experimental condition, both with and without primer, for a total of 160 specimens.

RESULTS

For three-way analysis of variance, the main effects of resins and treatment were statistically significant (p < 0.05), but the main effect of primer was not statistically significantly (p > 0.05). Without primer, the control group had the lowest bond strength (0 MPa). The three adhesive resin groups produced significantly higher bond strengths than the Lucitone resin groups. For the treated groups, nearly all sandblasted groups produced significantly lower bond strength than the other three treated groups. Meta-Dent to Met-etch treated group had the highest bond strength (23.9 MPa). With primer, the bond strengths of the Lucitone resin groups were significantly higher than the nonprimed groups, and the Lucitone resin-primed Rocatec treated group had the highest bond strength (14.8 MPa). For the three adhesive denture base resins, nearly all primed treated groups had significantly lower bond strengths than nonprimed groups.

CONCLUSIONS

Without primer, the Lucitone resin-sandblast treated group (control) had the lowest bond strength (0 MPa). The Meta-Dent denture base resin with the Met-etch treated group had the highest bond strength (23.9 MPa). With primer, the Lucitone resin-primed Rocatec-silane treated group had the highest bond strength (14.8 MPa). For the adhesive denture base resins, nearly all bond strengths of the primed treated groups were significantly lower than the values of the nonprimed groups.

Primary solitary amyloidosis of the spine: a case report and review of the literature

BACKGROUND

Amyloidosis is a term that encompasses a group of disorders that have as their common feature the intercellular deposition of the amyloid protein by several different pathogenetic mechanisms. Primary solitary amyloidosis, or amyloidoma, is a rare subset of amyloidosis in which the amyloid deposition is focal and not secondary to a systemic process or plasma cell dyscrasia. We present the second reported case of a cervical spine amyloidoma and discuss its presentation and management.

METHODS

This 58-year-old man presented with a 1-year history of intermittent chest pain that would radiate into both legs precipitated by valsalva maneuvers. A magnetic resonance imaging (MRI) of the cervical spine revealed a homogenously enhancing lesion focally involving the C-7 vertebral level with significant spinal cord compression. He underwent combined anterior and posterior decompressive procedures with instrumentation for spinal stabilization. Histopathology revealed amyloid deposits and a systemic work-up was negative for amyloidosis.

RESULTS

The patients is free of any tumor recurrence at 24 months and has a stable spine construct.

CONCLUSIONS

Primary solitary amyloidosis is a rare subtype of amyloidosis which, unlike other forms of amyloidosis, has an excellent prognosis with local resection. Diagnosis requires special stains and therefore a degree of suspicion for the disease. Management of vertebral amyloidoma involves aggressive local resection of the tumor when feasible and stabilization of the spine as mandated by the degree of tumor involvement. Complete evaluation for the diagnosis of systemic amyloidosis is essential for the management and prognostication of each case.

Phenotypic variability of CADASIL and novel morphologic findings

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is a non-arterio-atherosclerotic, non-amyloidotic arteriopathy affecting preferentially the small arteries and arterioles of the brain. The morphologic hallmark is the presence of a characteristic granular alteration of the arterial media that ultrastructurally corresponds to the accumulation of electron-dense material surrounding the smooth muscle cells. Although the presence of this granular osmiophilic material (GOM) was originally described as limited to brain vessels, identical electron microscopic findings have been demonstrated in the media of peripheral tissue arteries, allowing for a pathologic diagnosis of the disease by a simple skin, muscle or nerve biopsy. We report some atypical features identified in our CADASIL patients that broaden the phenotypic expression of this disease. Firstly, we identified a cortical infarct in an otherwise typical CADASIL patient. Secondly, we observed GOM in skin arteries of a 30-year-old man with hemiplegic migraine, the son of a woman who had died with CADASIL. This confirms that it may be possible to diagnose the disease at a preclinical stage by the ultrastructural evaluation of peripheral tissue biopsy material, particularly for individuals for whom there is a supporting family history. Thirdly, ultrastructural examination of the skin, and subcutaneous and striated muscle of an unrelated and apparently sporadic patient with neuropathologic and neuroradiologic evidence of CADASIL in meningeal and cerebral vessels failed to reveal diagnostic lesions in peripheral arteries. Thus, the possibility of a false-negative pathologic diagnosis in patients with a clinicoradiologic diagnosis of CADASIL, if one relies solely on a peripheral tissue biopsy, does exist. Additionally, we have identified heat shock proteins (Hsp70 and alphaB crystallin) and ubiquitin in the vascular myocytes of affected arteries. <alpha>B crystallin also seemed to be deposited extracellularly, which suggests that GOM also might be immunoreactive for alphaB crystallin.

Orthodontic adhesives and bond strength testing

A bracket bond failure is a frustrating occurrence in orthodontic practice. Because the location of the bond failure may indicate the probable cause, it is important to understand the significance of "bond strength" in a clinical application. Bonding in orthodontics can be studied using controlled clinical models or in vitro using simulated clinical models or more fundamental, isolated substrate models, in which bonding of an adhesive to tooth structure or a bracket is studied independently. With numerous adhesives and orthodontic band and bracket materials available as well as other orthodontic substrates besides enamel, such as esthetic ceramic restorations, in vitro models play an important role in characterizing the bonding potential of new systems. This article reviews bonding of orthodontic brackets and bands using various orthodontic adhesives to dental substrates from the perspective of bond strength and its measurement.

Accelerated aging affects color stability of provisional restorative materials

PURPOSE

The color stability of two shades each of five acrylic resin and seven resin composite provisional restorative materials was evaluated by reflection spectrophotometry following in vitro accelerated aging.

MATERIALS AND METHODS

Specimens of provisional restorative materials were polymerized according to manufacturers' instructions and aged in an artificial aging chamber with exposure to a total ultraviolet irradiation of 60 kJ/m2. Color was measured by CIE L*a*b* on a reflection spectrophotometer before and after aging. Color change (delta E*) was calculated and analyzed statistically.

RESULTS

Statistically significant changes in color were observed after accelerated aging. Nine of the 12 provisional materials tested showed perceptible color change of at least one of the shades tested. The most color-stable materials were the acrylic, Alike, and the resin composites, Luxatemp and Protemp Garant, which had no perceptible color changes under these conditions.

CONCLUSIONS

Some acrylic resin and composite provisional materials change color significantly and perceptibly when exposed to in vitro accelerated aging conditions.

A mouse model for X-linked adrenoleukodystrophy

X-linked adrenoleukodystrophy (X-ALD) is a peroxisomal disorder with impaired beta-oxidation of very long chain fatty acids (VLCFAs) and reduced function of peroxisomal very long chain fatty acyl-CoA synthetase (VLCS) that leads to severe and progressive neurological disability. The X-ALD gene, identified by positional cloning, encodes a peroxisomal membrane protein (adrenoleukodystrophy protein; ALDP) that belongs to the ATP binding cassette transporter protein superfamily. Mutational analyses and functional studies of the X-ALD gene confirm that it and not VLCS is the gene responsible for X-ALD. Its role in the beta-oxidation of VLCFAs and its effect on the function of VLCS are unclear. The complex pathology of X-ALD and the extreme variability of its clinical phenotypes are also unexplained. To facilitate understanding of X-ALD pathophysiology, we developed an X-ALD mouse model by gene targeting. The X-ALD mouse exhibits reduced beta-oxidation of VLCFAs, resulting in significantly elevated levels of saturated VLCFAs in total lipids from all tissues measured and in cholesterol esters from adrenal glands. Lipid cleft inclusions were observed in adrenocortical cells of X-ALD mice under the electron microscope. No neurological involvement has been detected in X-ALD mice up to 6 months. We conclude that X-ALD mice exhibit biochemical defects equivalent to those found in human X-ALD and thus provide an experimental system for testing therapeutic intervention.

Analysis of a sequenced cDNA library from multiple sclerosis lesions

To identify genes that are expressed in MS pathogenesis, we have analyzed a normalized cDNA library made from mRNA obtained from CNS lesions of a patient with primary progressive MS. Complementary DNA clones obtained from this library were subjected to automated DNA sequencing to generate expressed sequence tags. Analysis of this MS cDNA library revealed the presence of 54 cDNAs that were associated with immune activation and indicated the presence of an ongoing inflammatory response with evidence of both cell-mediated and humoral immune responses. The surprising finding was that 16 of the cDNAs encoded autoantigens associated with seven other autoimmune disorders, while only three of these 16 autoantigen cDNAs were present in a similarly constructed adult brain library. Such aberrant autoantigen expression could provide a source of secondary autoimmune stimulation that could contribute to the ongoing inflammatory response in MS. In addition, two cDNAs were found that mapped to a known MS susceptibility locus (5p14-p12): one encoded an excitatory amino acid transporter and the other a human homologue of the Drosophila disabled gene. This approach to the molecular biology of MS pathogenesis may help to illuminate previously unappreciated aspects of this disease.

Diagnostic criteria for the neuropathologic assessment of Alzheimer's disease

The provisional criteria proposed in 1985 by Khachaturian et al. emphasized numbers of plaques and neglected tangles, as did CERAD (Consortium to Establish a Registry for Alzheimer's Disease). The decision to set an arbitrary number of plaques as "pathologic" assumed that some neuritic plaques are a normal phenomenon in the aging brain. Neuritic plaques and neurofibrillary tangles are age-related lesions, but they are pathologic (i.e., lesions) no matter how many there are. In a clinically demented patient without vascular or other neurodegenerative lesions, a clinico-pathologic diagnosis of AD (a clinico-pathologic entity) can be made with a high level of confidence by demonstrating, and without counting, plaques and tangles. The vast majority of AD cases are straightforward, and diagnostic lesions can be appreciated with a simple silver stain. If patients' histories are unknown or uncertain, the clinical significance of the observed plaques and tangles must remain debatable. This is the essence of the consensus statement with which I wholeheartedly agree. In such cases without a dementia history, one can offer a neuropathologic diagnosis of Senile or Pre-senile Cerebral Disease (not "dementia") of the Alzheimer type. Precise clinico-pathologic correlations and some quantitative measures are needed for elucidating the pathogenesis of AD and for establishing a primary dementing diagnosis when AD is mixed with other dementing diseases. These correlations must be based on periodic and fairly extensive neuropsychological testing followed shortly thereafter by a detailed postmortem neuropathologic evaluation.

Hardness and stress-corrosion of rubber dam clamps

Rubber dam clamps fracture infrequently during use. There are no American National Standards Institute or International Standards Organization standards for their manufacture. The purpose of this study was to measure the hardness of the clamps and test their resistance to a stress-corrosion test. Upper molar, lower molar, and premolar clamps were obtained from two manufacturers (A, B). The Rockwell C hardness at four sites on the bow of each clamp was then determined. Fresh clamps were placed on blocks corresponding to the average buccal-lingual dimension of the tooth on which they would be used. These blocks were then submerged in room temperature 5.25% sodium hypochlorite for 20 min and then allowed to air dry for 30 min. This was repeated 10 times. Rockwell C hardness values ranged from C30 to 38, with the clamps of manufacturer B being significantly harder. None of the clamps from manufacturer B cracked or corroded. When a third batch received from manufacturer A was tested in the same manner, none of the clamps fractured or corroded either.

Human leukocyte antigens and cytokine expression in cerebral inflammatory demyelinative lesions of X-linked adrenoleukodystrophy and multiple sclerosis

The two most common forms of X-linked adrenoleukodystrophy (X-ALD) are the cerebral forms (CER) with an inflammatory demyelinating reaction that resembles multiple sclerosis, and adrenomyeloneuropathy (AMN) which involves primarily the spinal cord and in which the inflammatory reaction is mild or absent. We found no significant association between the childhood cerebral form (CCER) or AMN and the human leukocyte (HLA) class I and Class II antigens including the class II DR2 haplotypes associated with multiple sclerosis. Inflammatory cytokine (tumor necrosis factor-alpha, interleukin-1 beta, interleukin-4, interleukin-6 and interferon-gamma) gene expression was increased in multiple sclerosis brain lesions, as has been reported previously, but much less so in CER brain lesions. These findings suggest that the pathogenesis of the inflammatory response in X-ALD differs from that in multiple sclerosis.

Color accuracy of resin cements and try-in pastes

The color accuracy of resin composite cements and their corresponding try-in pastes was assessed. Three shades of three brands were compared using the cements alone and in contact with a standard porcelain disk. There were significant differences in color between resin cements and their corresponding try-in pastes. The addition of a 1-mm-thick porcelain disk greatly reduced the apparent color differences. The color of resin cements changed over time, but not significantly. Baseline measurements of resin cement colors were compared and measurements made after 24 hours of storage. Color changes were statistically significant but not perceptible, and all samples became slightly darker with age.

Bond strength of orthodontic composite cement to treated porcelain

A porcelain-fused-to-metal ceramic was prepared for bonding by five treatments: sandblasting, sandblasting and silanating, hydrofluoric acid etching, hydrofluoric acid etching and silanating, and 600-grit polishing and silanating. Two commercial, all-purpose bonding agents were used to bond a composite cement to the porcelain samples. In vitro tensile bond strengths were compared with samples for which no bonding agent was used. Highest bond strengths (22 to 41 MPa) were obtained, with one exception, when the porcelain surface was silanated; however, the use of silane increased the occurrence of porcelain fracture on debonding. Composite cement bonded without bonding agent to nonsilanated porcelain prepared by sandblasting or etching with hydrofluoric acid had bond strengths of 6.5 MPa and 18 MPa, respectively, with all bond failures at the bracket/composite interface. The use of all-purpose bonding agents and silanating agents may not be necessary for adequate orthodontic direct bonding.

Motor neuron disease and angiotropic lymphoma

BACKGROUND

The number of patients with motor neuron disease (MND) and a concomitant hematologic disorder appears to be overrepresented. Angiotropic large cell lymphoma, a rare and aggressive type of lymphoma, has been associated with MND only once (to our knowledge) prior to this report. There are more than 35 cases of MND associated with lymphoma or monoclonal gammopathy reported in the literature. The nature of this association remains disputable.

OBJECTIVE

To investigate whether the association between some MNDs and certain hematologic disorders is coincidental or pathogenetically related.

CASE PRESENTATION

We describe the clinical and neuropathologic findings in a case involving a 70-year-old man with a rapidly progressive lower MND who at autopsy also exhibited angiotropic large cell lymphoma without ischemic lesions in the nervous system.

CONCLUSIONS

This case supports the notion that the association between some MNDs and certain hematologic disorders is not coincidental but pathogenetically related. A 2-hit hypothesis is proposed in which an initial abnormal glycosylation in motoneurons would require the production of an appropriate autoantibody for disease expression.

Color stability of heat-activated and chemically activated fluid resin acrylics

PURPOSE

Heat- and chemically activated acrylics processed by compression molding or fluid resin matrix techniques for fabrication of partial dentures were evaluated for color stability by reflection spectrophotometry after accelerated aging.

MATERIALS AND METHODS

Samples of heat-activated (L199, PDON, SB) and chemically activated (PR, PVAR, SC) denture base acrylics were polymerized according to manufacturers' instructions. Samples were aged in an artificial aging chamber, and color was measured by CIE L*a*b* on a reflection spectrophotometer at baseline and after each of three aging cycles.

RESULTS

At 450 kJ/m2, color changes of two chemically activated acrylics (PR and SC) were perceptible. PR became less red, whereas SC became darker and more yellow. The most color-stable acrylics were a heat-activated resin (SB) and one chemically activated acrylic (PVAR).

CONCLUSIONS

The three heat-activated acrylics tested were more color-stable than two of the chemically activated acrylics, but one chemically activated acrylic (PVAR) recommended for a fluid resin matrix technique was color-stable.

Primary leptomeningeal histiocytic lymphoma in a young child

A 20-month-old boy had an 8-week history of vomiting, lethargy, generalized muscle weakness, and seizures. There was no history or clinical signs of an underlying systemic disease or an immunodeficiency. Cerebrospinal fluid (CSF) had 99 nucleated cells/cu mm, malignant cells, high protein and normal glucose. CT and MRI scans showed diffuse meningeal enhancement around the brain and spinal cord, but no parenchymal involvement. Biopsy of the leptomeninges showed malignant cells with marked nuclear pleomorphism and prominent clear to eosinophilic cytoplasm. The immunohistochemical studies were positive for histiocyte-macrophage markers and were negative with T and B cells, Ki-1, neural and glial cell antibodies. Multiple tests revealed no other site of disease. The patient died 3 months after onset of treatment despite intensive i.v. and intrathecal chemotherapy. We have not found any other reported case of primary histiocytic leptomeningeal lymphoma in a young child.

Coexistence of Huntington's disease and familial amyotrophic lateral sclerosis: case presentation

We present the clinical, molecular genetic and neuropathological findings of an 81-year-old man with concurrent Huntington's disease (HD) and familial amyotrophic lateral sclerosis (FALS). His mother had been diagnosed clinically as having ALS. There was no known family history of HD, but a maternal uncle had died in a chronic care psychiatric hospital. The diagnosis of HD in the patient was suspected at age 66, after 8 years of personality change, hallucinations, agitation, cognitive decline and choreoathetosis. No symptoms of motor neuron disease were noticed at that time, but progressive weakness developed later. Postmortem examination revealed cerebral atrophy, marked atrophy of basal ganglia (grade 3), and atrophy of brain stem and spinal cord. The neostriatum displayed massive neuronal loss and gliosis. The neocortex showed changes characteristic of Alzheimer's disease. Pathological lesions also included loss of neurons and gliosis in the anterior horns, Clarke's columns and the hypoglossal nuclei; degeneration of the lateral corticospinal tracts, dorsal spinocerebellar tracts and fasciculus gracilis; and rare Bunina bodies and ubiquitin-positive filamentous skeins in motor-neuron perikarya. Molecular analysis demonstrated chromosome 4p16.3 expansion of trinucleotide repeats characteristic of HD. Analysis of Cu,Zn superoxide dismutase gene and heavy neurofilament subunit gene failed to demonstrate mutations. The concurrence of HD and FALS in our patient and three previously reported cases did not appear to be associated with cosegregation in other family members.

Infarcted spinal schwannoma: an unusual MR finding

We present a case of infarcted schwannoma of the thoracic spine in a patient with acute cord compression. MR images did not enhance after contrast administration, which is highly atypical for schwannoma, but was in keeping with the pathologic findings in this case.

Accuracy of wax, autopolymerized, and light-polymerized resin pattern materials

PURPOSE

The marginal fit of MOD inlay and full-crown patterns fabricated from wax, autopolymerized acrylic resin, and two light-polymerized, diacrylate resin pattern materials was compared on standardized dies.

MATERIALS AND METHODS

Four pattern materials were studied-two light-polymerized, diacrylate resin materials (Palavit G LC and Triad VLC Burnout Paste), an inlay wax, and an autopolymerized resin (Duralay). Patterns were fabricated using incremental and bulk techniques on stone dies made from addition silicone impressions of American Dental Association MOD and full-crown master dies. Gaps were measured with a measuring microscope in four marginal areas on the master dies at 1 and 24 hours after fabrication.

RESULTS

For the MOD inlay patterns, marginal gaps ranged from 7 to 23 microns, and the light-polymerized, diacrylate resins and autopolymerized acrylic resin material had statistically smaller gaps than the inlay wax. For the full-crown patterns, marginal gaps ranged from 10 to 23 microns, with the exception of the autopolymerized acrylic resin prepared by the bulk technique (40 to 46 microns). With the incremental technique, the light-polymerized, diacrylate resins and inlay wax had statistically smaller gaps than the autopolymerized acrylic resin material. Overall, the incremental technique produced equal or smaller marginal gaps than the bulk technique for full-crown patterns. Generally, the patterns measured at 1 hour had smaller marginal gaps than at 24 hours.

CONCLUSIONS

When measured on intra- and extracoronal master dies, the light-polymerized, diacrylate resins had equal or better marginal fit, compared with wax or autopolymerized acrylic resin, and were less affected by placement technique and storage. The marginal gaps of all four pattern materials ranged from 7 to 46 microns and are within the range of clinical acceptability.

Bond strength of composites to hybrid ionomers

Tensile bond strengths among three different hybrid ionomers and two different hybrid composites were evaluated. With one exception, bond strength to a high-modulus composite (Z-100) was higher than that to a low-modulus composite (Charisma). Thermocycling lowered the bond strength of Charisma, whereas storage for 3 months increased the bond strength of Z-100 compared to storage for 24 hours. Etching the hybrid ionomers with phosphoric acid had no effect on bond strength.

Tensile and tear properties of dental dam

The tensile and tear properties of highly extensible latex are sensitive to specimen shape. Three specimen shapes (ASTM D412 Die C dumbbell tensile specimen, rectangular tensile specimen with 1.74 mm hole, and ASTM D624 Die C tear specimen) were evaluated for proposed ANSI/ADA specification #90 for dental dams. Fresh and aged dental dams from two manufacturers (Aseptico and Hygenic) in three weights (thin, medium, and heavy) and from two other manufacturers (Ivory and Ivoclar) in one weight (medium) were tested. Means and standard deviations of 10 specimens for tensile strength (MPa), elongation (%), and tear strength (kN/m) are included herein. Data were analyzed by analysis of variance. Means were compared by a Tukey-Kramer interval calculated at the 0.05 significance level. The use of the dumbbell and tear specimens for the evaluation of dental dam should be reconsidered. The rectangular specimen with a hole is recommended for use in the proposed specification because of its sensitivity to condition (fresh versus aged) and manufacturer.

Long-term follow-up of outpatient interdisciplinary pain management with a no-treatment comparison group

The long-term psychosocial and physical functioning impact of an outpatient interdisciplinary pain management program was evaluated by comparison of pain management completors and a no-treatment group. Although pain intensity did not change and there were no significant differences between groups in several aspects of daily activity, the group that completed the program reported a greater sense of control over pain, had a more hopeful outlook on the future, perceived pain as interfering less with their life, and used strategies that are considered adaptive for long-term management of pain. The results suggest that patients with chronic, complex pain problems can improve perceptions regarding pain control and reduce the interference of pain in their lives. Outlook regarding the future was identified as a critical assessment and treatment variable. Individuals who were more optimistic about the future perceived a greater control over pain and endorsed coping strategies that involve diverting attention, ignoring pain sensations, and making coping self-statements. Although pain intensity rating did not differ, individuals who had a more pessimistic outlook on life considered pain to interfere with their work activity, mood, relations with other people, and overall enjoyment of life to a greater extent than individuals who were more optimistic.

Performance of composite finishing and polishing instruments after sterilization

PURPOSE

To evaluate the performance before and after sterilization of Enhance and Min-Identoflex finishing and polishing systems on TPH and Z100 composites.

MATERIALS AND METHODS

Finishing and polishing instruments consisted of a light-cured resin cup impregnated with an abrasive and a silicon dioxide impregnated rubber cup. Sterilization methods included microwaving and autoclaving.

RESULTS

Performance of the finishing and polishing instruments were affected more by the composite being finished and polished than by autoclaving or microwaving.

Surface roughness of composites and hybrid ionomers

This study examined the average surface roughness (Ra, micron) of two composites and three different hybrid ionomers before and after treatment with a 12-fluted finishing bur, two finishing and polishing systems, and a hybrid-ionomer glaze for the hybrid ionomers. The 12-fluted finishing bur produced a roughened surface with all materials compared to the initial surface formed and cured against glass. Both the Enhance Finishing and Polishing System and the Sof-Lex contouring and polishing disks produced smoother surfaces for the composites, Revolution and Charisma, compared to the hybrid ionomers, Fuji II LC, Variglass, and Vitremer. However, the Fuji II LC glaze and the Vitremer glaze created smoother surfaces compared to Revolution finished with the Enhance system. Overall, the Sof-Lex disk system produced the smoothest surfaces for all materials.

Bond strength of composite to sound and artificial carious dentin

PURPOSE

To determine the in vitro bond strength of a composite (Herculite XRV) to sound dentin and artificial carious lesions in dentin.

MATERIALS AND METHODS

Buccal and lingual surfaces from extracted human molar teeth were ground to expose sound dentin surfaces. The buccal surface was maintained as sound dentin, while an artificial carious lesion was created in the lingual surface using an acidified gelatin gel. A bonding agent (Optibond) was applied to both buccal and lingual surfaces with and without prior etching with 37.5% phosphoric acid. The composite was applied and debonded under tension after 24 hours in water at 37 degrees C.

RESULTS

Both sound dentin (23.1 MPa) and etched sound dentin (22.2 MPa) had similar bond strengths, whereas artificial carious lesions in dentin that had been etched (11.8 MPa) and non-etched dentin lesions (8.8 MPa) had significantly lower bond strengths. Adhesive failures were greatest for dentin lesions (60-95%) and least for sound dentin(40-50%). Etching with phosphoric acid did not improve the bond strength of composite to sound dentin or artificial carious lesions in dentin.

Fabrication of biodegradable polymer scaffolds to engineer trabecular bone

We present a novel method for manufacturing three-dimensional, biodegradable poly(DL-lactic-co-glycolic acid) (PLGA) foam scaffolds for use in bone regeneration. The technique involves the formation of a composite material consisting of gelatin microspheres surrounded by a PLGA matrix. The gelatin microspheres are leached out leaving an open-cell foam with a pore size and morphology defined by the gelatin microspheres. The foam porosity can be controlled by altering the volume fraction of gelatin used to make the composite material. PLGA 50:50 was used as a model degradable polymer to establish the effect of porosity, pore size, and degradation on foam mechanical properties. The yield strengths and moduli in compression of PLGA 50:50 foams were found to decrease with increasing porosity according to power law relationships. These mechanical properties were however, largely unaffected by pore size. Foams with yield strengths up to 3.2 MPa were manufactured. From in vitro degradation studies we established that for PLGA 50:50 foams the mechanical properties declined in parallel with the decrease in molecular weight. Below a weight average molecular weight of 10,000 the foam had very little mechanical strength (0.02 MPa). These results indicate that PLGA 50:50 foams are not suitable for replacement of trabecular bone. However, the dependence of mechanical properties on porosity, pore size, and degree of degradation which we have determined will aid us in designing a biodegradable scaffold suitable for bone regeneration.

Incorrect diagnosis of Alzheimer's disease. A clinicopathologic study

OBJECTIVES

To examine the accuracy of clinical diagnoses of Alzheimer's disease (AD) in subjects enrolled in the Rochester Alzheimer's Disease Project (RADP) who were examined at autopsy, and to present a list of clinical "red flags."

DESIGN

Autopsy examination of both prospective and retrospective subjects consecutively enrolled in this clinicopathologic study of the RADP.

SETTING

University hospital and research center, using a multidisciplinary geriatric neurology clinic, satellite clinics, nursing home visits, and home visits.

PATIENTS

One hundred seventy subjects clinically diagnosed as having AD who were enrolled in the RADP between 1983 and 1993 underwent neuropathologic examination. Of these, 93 had been enrolled prospectively and 77 retrospectively.

MAIN OUTCOME MEASURES

Agreement between clinical and pathologic diagnoses.

RESULTS

One hundred forty-nine subjects of 170 clinically diagnosed as having AD fulfilled the pathologic criteria for AD, yielding an accuracy rate of 88%. Of 93 subjects enrolled prospectively and diagnosed as having AD, 83 (90%) met the histologic criteria for AD. Of the 77 subjects enrolled retrospectively, neuropathologic examination indicated definite AD in 66 (86%).

CONCLUSIONS

There was a high correlation between clinicians' diagnoses and final pathologic diagnoses. The most common clinical errors involved the misdiagnosis of dementias due to Parkinson's disease and cerebrovascular disease. There was no significant difference in the accuracy rates of subjects enrolled prospectively and retrospectively.

Color stability of facial prostheses

The limited service of facial prostheses is the result of degradation of the elastomer and color instability. Deterioration may be caused by many factors, which include environmental exposure and changes in humidity. This investigation assessed the efficacy of an additive, intrinsic, broad-spectrum ultraviolet light absorber on the color stability of a pigmented facial elastomer. Samples were weathered artificially and outdoors at exposure levels of radiant energy of 150 to 450 kJ/m2. The samples changed color slightly but perceptibly. Artificial aging caused a greater change than outdoor aging. The ultraviolet light absorber UV-5411 did not protect the samples from color changes.

Alpers' syndrome presenting with seizures and multiple stroke-like episodes in a 17-year-old male

Alpers' syndrome is a progressive neurodegenerative disorder with liver disease that usually presents in the first few years of life. Only rarely have patients presented later in life with delayed onset of Alpers' syndrome. Herein we present a case of a 17-year-old male with a progressive 8-month course of severe headaches, multiple stroke-like episodes with visual deficits, and seizures that concluded with acute hemorrhagic pancreatitis. Neuropathological findings were characteristic for Alpers' syndrome: neurodegeneration and astrogliosis of the occipital cortices including the striate cortices, similar but less advanced changes in the parietal cortices, right Ammons horn sclerosis, degeneration of the posterior columns, and mild cerebellar Purkinje cell loss. Examination of the liver revealed extensive centrilobular hepatocyte necrosis. Skeletal muscle did not contain ragged red fibers, nor were there mitochondrial DNA point mutations characteristic for mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS).

The pathology of peroxisomal disorders with pathogenetic considerations

Peroxisomal disorders are rare systemic maladies in which specific major organ systems are typically involved: most importantly the central nervous system (CNS), but also the peripheral nervous system, eyes, liver, adrenal, kidney and skeleton. Zellweger syndrome (ZS) is the most severe of the generalized types and exhibits major neocortical migration defects, less severe and non-inflammatory white matter lesions, and dysmorphic features. In adrenoleukodystrophy (ALD) the major lesion again is in the CNS, but consists of extensive dysmyelination/inflammatory demyelination without neuronal migration defects or dysmorphism. In adrenomyeloneuropathy long tract degeneration of spinal cord, peripheral neuropathy, and variable CNS dysmyelinative to inflammatory demyelinative lesions are the dominant nervous system lesions. Saturated very long chain fatty acids, either free in the cytoplasm of affected endocrine cells or as components of membrane lipids (e.g. gangliosides, glycerophospholipids, and proteolipid protein) in axons or myelin, may be central to the pathogenesis of these neuronal migration defects, dysmyelination/inflammatory demyelination and spinal tract degeneration. Cytokines, particularly tumor necrosis factor-alpha, and delayed cellular hypersensitivity appear to be major secondary pathogenic factors in ALD.

Selected leukodystrophies

The clinicopathologic profiles of the major leukodystrophies (adreno-leukodystrophy, metachromatic leukodystrophy, globoid cell leukodystrophy or Krabbe's disease, Pelizaeus-Merzbacher disease, and spongy degeneration of infancy or Canavan's disease) are reviewed. Particular attention is paid to distinctive imaging characteristics, molecular advances, pathogeneses, and potential therapies.

Bond strength of composite to air-abraded enamel and dentin

Human enamel and dentin were prepared with an air abrasion unit (KCP-2000), using two particle sizes (27 micrometers and 50 micrometers) of aluminum oxide. In vitro tensile bond strengths of a composite resin were determined after three enamel and three dentin surface treatments. Enamel treatments were: air abraded only, E-1; air abraded + adhesive, E-2; air abraded + acid etch + adhesive, E-3. Dentin surface treatments were air abraded only, D-1; air abraded + adhesive/no primer, D-2; air abraded + primer + adhesive, D-3. Etched enamel and dentin prepared with 600-grit SiC paper and adhesive served as controls. There were 10 replications for each condition. A dentin bonding system (Optibond) and a composite resin (Herculite XRV) were bonded to treated surfaces by light curing in an inverted, truncated cone die with a bond diameter of 3 mm. Samples were stored at 37 degrees C and 100% relative humidity for 24 hours and debonded in tension using a Universal Testing Machine at a 0.05 cm/min crosshead speed. Based on analysis of variance, there was no statistical difference between 27 micrometers and 50 micrometers aluminum oxide abrasive for both enamel and dentin. For enamel bond strengths, E-2 was significantly higher than E-1, and E-3 was significantly higher than E-1 and E-2. E-1 and E-2 were significantly lower than the control, while E-3 was not significantly different from the control (P < or = 0.05). For dentin bond strengths, D-2 was significantly higher than D-1, and D-3 was significantly higher than D-1 and D-2. All treatments except D-3 were significantly lower than the control (P < or = 0.05). Air-abrasion treatment of enamel and dentin alone resulted in reduced in vitro bond strengths as compared to etched enamel and dentin prepared with dentin adhesive and dentin primer.

Practice guidelines for autopsy pathology. Autopsy procedures for brain, spinal cord, and neuromuscular system. Autopsy Committee of the College of American Pathologists

The Autopsy Committee of The College of American Pathologists has prepared this guideline in conjunction with representatives of other organizations to assist pathologists in autopsy procedures for brain, spinal cord, and neuromuscular system. The guideline is to be regarded as being primarily an educational tool. Application of these recommendations on autopsy reporting is to be made on the basis of the judgment of the pathologist engaged in a specific case.

Serial magnetic resonance imaging in isolated angiitis of the central nervous system

Isolated angiitis of the central nervous system (IACNS) is a rare form of vasculitis restricted to the CNS. We report serial MRI findings in a biopsy-proven case of IACNS. MRI showed extensive white matter and subcortical disease. Before specific treatment, neuroimaging showed the development of new lesions corresponding with an overall progressive clinical course of the illness; the post-treatment MRI showed improvement.

Color stability of light-cured and post-cured composites

PURPOSE

To determine the color stability of five composites after light-curing and recommended post-curing using reflection spectrophotometry.

MATERIALS AND METHODS

Samples of the composites were prepared as disks 10 mm in diameter and 1 mm thick. The pre-cured samples were prepared with a clear plastic sheet on the top and bottom of disk, pressed between two glass slabs to the thickness of the mold, and then removed from between the glass slabs. The color of the samples was measured with the clear plastic sheets in place. The color of the composites before curing served as the control.

RESULTS

Light-curing caused barely perceptible to perceptible color changes for all of the composites from the pre-cured shade. Clearfil and TrueVitality changed color significantly more than Charisma, Conquest C&B and Herculite XRV. Once the composites were light-cured, post-curing caused no further perceptible changes in shade.

Properties of hand-held spreaders after simulated use

Root canal spreaders are available in a wide variety of diameters, lengths, and tapers. Proposed ANSI/ADA Specification no. 71 standardizes certain properties of these instruments; however, none of these testing procedures subjects the instruments to conditions of clinical usage. Diameters (D3 and D16) and taper of 40 D11T root canal spreaders from each of three companies [Endeco (EN), Hu-Friedy (HF), and Premier (PR)] were measured. Permanent angular deformation of the instrument tip was measured by a bend test apparatus for four conditions: (group A) as-supplied control, (group B) spreader sterilized in an autoclave for 10 cycles, (group C) spreader inserted 50 times at a rate of 200 mm/min into plastic blocks with a canal curvature of 30 degrees, and (group D) spreader sterilized for 10 cycles and then inserted in blocks as described. All instruments passed the bend test in proposed specifications under all conditions. The EN spreader was more susceptible to permanent deformation than HF or PR. There were no statistical differences among the control and the three simulated clinical conditions.

Adrenoleukodystrophy: molecular genetics, pathology, and Lorenzo's oil

Knowledge about adrenoleukodystrophy (ALD), a disorder which was described first in 1923, has increased greatly during recent years. The principal biochemical abnormality, the presumed enzyme defect, and the gene defect, have been defined. A dietary therapy has been proposed and attracted world-wide attention through a motion picture. Nevertheless, many questions remain and cannot be answered without a more fundamental understanding of pathology and pathogenesis. This article will provide a review of the history, clinical features, pathology, biochemistry, and the gene defect, and then appraise current efforts to clarify pathogenesis and develop therapeutic approaches.

Color stability of hybrid ionomers after accelerated aging

PURPOSE

The color stability and surface roughness of three commercial hybrid ionomers were determined in vitro after accelerated aging. Three shades of each hybrid ionomer prepared in light-cured and dark-cured conditions were tested.

MATERIALS AND METHODS

Samples were aged in an artificial aging chamber by subjecting them to total ultraviolet light irradiation of 150 kJ/m2 over a period of 77 hours. Color (CIE LAB system) was measured before and after aging on a reflection spectrophotometer. Surface roughness was measured with a profilometer.

RESULTS

After accelerated aging, all samples became lighter. Photac-Fil Aplicap (ESPE-Premier, Norristown, PA) and Fuji II LC (GC America, Chicago, IL) also became less chromatic (less red and less yellow). Among the light-cured samples, Fuji II LC had the greatest change in color followed by Photac-Fil Aplicap and Vitremer (3M Dental Products, St Paul, MN). For the dark-cured samples, Fuji II LC had the greatest change in color followed by Vitremer and Photac-Fil Aplicap. There were no differences in delta E* between the two lightest shades, but the darker shades of each product showed the greatest changes in color. All samples became significantly rougher after aging.

CONCLUSIONS

Hybrid ionomers changed color significantly and perceptibly after in vitro accelerated aging. Surfaces became significantly rougher and showed evidence of cracking and degradation.

Retention capacity of the bracket bases of new esthetic orthodontic brackets

Tensile bond strength and bond failure locations were evaluated in vitro for three types of direct bonding cements (self-cured diacrylate, dual-cured diacrylate, and dual-cured glass ionomer) with four types of brackets (stainless steel, polycarbonate, ceramic, and ceramic-polycarbonate) by using a plastic cylinder as the substrate. A highly filled, self-cured diacrylate cement gave the highest bond strength values with the polycarbonate, stainless steel, and ceramic-polycarbonate brackets. A dual-cured diacrylate cement gave the highest bond strength with a mechanically retained ceramic bracket. The dual-cured glass ionomer cement gave the highest bond strength values with a silanated ceramic bracket. All bond failures occurred at the bracket/cement interface with the stainless steel bracket, whereas failure locations were at the bracket/cement interface and within the cement with the polycarbonate bracket. Bond failures occurred between bracket and cement, within the cement, and within the bracket with the ceramic brackets.

Surface roughness of opalescent porcelains after polishing

Intraoral porcelain polishing is an important consideration in many restorative and esthetic procedures. Several porcelain polishing systems as well as improved ceramics are now commercially available. This study evaluated the efficacy of eight different intraoral polishing techniques on three opalescent porcelains. The surface roughness (Ra) of the opalescent porcelains were measured before and after the polishing procedures with a profilometer. These results were then compared to self-glazed and overglazed control groups. Five of the techniques tested produced surfaces smoother than glazing. The use of a 30-fluted carbide bur before diamond polishing paste produced the smoothest surfaces.

Parkinsonian features of eight pathologically diagnosed cases of diffuse Lewy body disease

Premortem diagnosis of diffuse Lewy body disease (DLBD) is difficult, and knowledge of the parkinsonian features of DLBD might facilitate the diagnosis. In this study, we compared the parkinsonian syndrome of DLBD and Parkinson's disease (PD). We retrospectively reviewed the charts of Columbia-Presbyterian Medical Center (CPMC) Brain Bank cases (1989-1993) with pathologically diagnosed DLBD or PD, and the literature on the parkinsonian features in DLBD patients presenting with parkinsonism. Parkinsonism accompanied or preceded cognitive/psychiatric changes in most CPMC cases (DLBD 100%, PD 88%). DLBD had an earlier mean age of onset than PD did (57 versus 64 years), a similar male:female ratio (1.7:1 versus 1.9:1), and similar mean disease duration (12-13 years). Cognitive/psychiatric changes were less frequent in PD than in DLBD (65 versus 100%) (p = 0.025). Rest tremor was specifically mentioned in 29% of DLBD versus 56% of PD (p = 0.10). Bradykinesia was less common in PD (56% versus 86%) (p = 0.05). All those with PD responded to L-Dopa, as did all those with DLBD who received L-Dopa. In conclusion, there are subtle differences between PD and DLBD in age of onset, frequency of cognitive/psychiatric changes, bradykinesia, and rest tremor. However, even when taken together, these cannot be used to distinguish these entities.