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J Arends

Publications and source records attributed to J Arends.

At least 37 records · Page 2Linked to original sources
PubMed1997

A computer-assisted videodensitometric method to visualize mineral distributions in in vitro and in vivo formed root caries lesions.

A computer-assisted videodensitometry (CAV) method is presented for the microradiographical mineral determination and mineral visualization of in vitro and in vivo formed dentin lesions. The method employs as essential steps (1) image digitizing by a CCD camera, (2) conversion of gray values to equivalent aluminium thicknesses and (3) conversion of aluminium thickness to vol% of mineral. Procedure and accuracy are described. The CAV method is illustrated for dentin lesions formed in vitro as well as for clinical root caries lesions. The CAV method is especially advantageous for clinical lesions because it can be employed for very complex mineral distributions and irregular lesion outlines. In given areas of interest, the mineral distribution (in vol%) can be plotted in 3D form in pseudo-colors. Conventional microradiographical profiles can be obtained directly from the CAV images. For in vitro lesions, the mineral distribution parameters, lesion depth, mineral loss, and mineral acquisition values can be generated from CAV images with a reproducibility of better than 7%. The CAV method is a valuable tool in quantitative mineral studies of clinical lesions in extracted teeth as well as in in situ lesion investigations.

Absorptiometry, Photon↗
PubMed1997

Penetration of varnishes into demineralized root dentine in vitro.

In this paper the penetration of three different varnishes employed in caries prevention (Duraphat, Fluor Protector and Cervitec) into demineralized dentine is quantified using confocal laser scanning microscopy. The results show that the varnish penetration into lesions about 85 microns in depth if for Cervitec about 35 microns and considerably less for Duraphat and Fluor Protector. The penetration is into the dentinal tubules and is influenced by dentinal tubule direction. The drying procedure--pretreatment of the dentine--influences the penetration, though sizeably only for Cervitec applications. This paper shows that varnish penetration into the tissue and presumably 'sealing' tubules completely or partly is valuable with respect to root caries prevention and hypersensitivity.

Adolescent↗
PubMed1997

Major topics in quantitative microradiography of enamel and dentin: R parameter, mineral distribution visualization, and hyper-remineralization.

Three aspects of quantitative transverse microradiography are described and discussed: (1) the average mineral loss parameter of enamel or dentin lesions (R) in vol%; (2) mineral distribution visualization of lesions by means of a computer-assisted videodensitometric (CAV) method; and (3) the microradiography of hyper-remineralized lesions. "R", defined as the average amount of mineral lost (or gained) in a lesion per unit lesion length, is a useful parameter in dental caries. The results show that, in vitro, R is about constant over the demineralization period for enamel and dentin. This was found even for quite different dissolution kinetics. R is strongly reduced by the presence of small amounts of fluoride in the demineralizing system. R of dentin lesions is smaller than for enamel lesions. We conclude that the mineral loss value (delta Z) and the lesion depth (ld) are in general dependent parameters during in vitro or in situ studies on enamel or dentin. During lesion formation, mineral loss from the lesion and acid penetration in the tissue are obviously linked. This is possible only if the mineral content in the lesion does not change very much after passage of the lesion front. The CAV method presented is illustrated for enamel lesions formed in vitro and in situ.

Absorptiometry, Photon↗
PubMed1997

Electron probe microanalysis and transverse microradiography studies of artificial lesions in enamel and dentin: a comparative study.

In cardiology and research involving the interactions between restorative materials and dental hard tissues, it is important for small changes in tooth mineral content to be measurable. Currently, transverse microradiography (TMR) is the most accepted tool for the above purpose. Electron Probe Microanalysis (EPMA) can yield both qualitative identification of elements and quantitative compositional information. The purpose of this study was to compare the mineral distribution in well-defined artificial lesions, in dentin and enamel, by the use of both TMR and EPMA on the same sample. The good correlation between the two sets of data validates EPMA as a technique and helps in the interpretation of its results. The data from TMR analysis are expressed as vol% of mineral, while EPMA gives the levels of Ca and phosphate in wt%. The conversion between the two sets of data is complicated by the fact that local density is, as yet, unknown.

Analysis of Variance↗
PubMed1997

Caries development in fluoridated and non-fluoridated deciduous and permanent enamel in situ examined by microradiography and confocal laser scanning microscopy.

The aim of the study was to compare initial caries development in fluoridated and non-fluoridated deciduous and permanent enamel in situ. Enamel slabs were mounted in removable appliances and worn for 4 wks. Significantly larger lesions developed in deciduous than in permanent enamel when no topical fluorides were used. Fluoride mouthrinsing partly prevented lesion development in deciduous and completely in permanent enamel. Initial enamel caries not detected by microradiography can be visualized by CLSM (confocal laser scanning microscopy).

Dental Caries↗
PubMed1997

The caries-preventive effect of titanium tetrafluoride on root surfaces in situ as evaluated by microradiography and confocal laser scanning microscopy.

The aim of the present study was to investigate the cariostatic effect of titanium tetrafluoride (TiF4) on in situ-induced lesions on human root surfaces. Analysis of the samples was carried out by quantitative microradiography (TMR) and confocal laser scanning microscopy (CLSM). Pre-molar roots, sectioned into four pieces, were used for sample preparation. Before they were mounted into the recesses prepared in the acrylic intra-oral appliances, two root pieces from each tooth were treated with 4% TiF4 for 1 min, while the remaining two pieces served as controls. The appliances were worn by 12 volunteers for 4 wks. After 4 wks with no fluoride supplementation, the root pieces were removed and analyzed by TMR and CLSM. The TMR results showed that the TiF4 treatment reduced lesion depth and total mineral loss by 56% and 62%, respectively. CLSM images agreed well with the TMR measurements. A dense light-reflecting surface layer with almost intact subsurface structures was evident in the TiF4-treated samples.

Bicuspid↗
PubMed1997

Raman spectroscopy in dental research: a short review of recent studies.

The Raman spectroscopic technique enables us to obtain vibrational (IR and far-IR) spectra of minerals by analyzing scattered light caused by (visible or near-visible) monochromatic laser excitation. The method possesses several advantages over IR absorption, including simple sample preparation, easy spectral/band analysis, and linear-response to mineral/chemical concentrations. In micro-Raman spectrometer systems, samples are positioned under an optical microscope, and specimens can be scanned with a lateral resolution (approximately 1 mm). In this paper, recent applications of micro-Raman spectroscopy and near-infrared Fourier transform Raman spectroscopy in the study of dental hard tissues and of calculus are reviewed. Special attention is given to mineral components in enamel, dentin, and calculus, and to calcium fluoride formed in/on enamel. The results from the use of an Ar(+)-laser/grating-based micro-Raman spectrometer show that: CaF2 formed in/on enamel by APF treatment is detectable and different from pure CaF2; and with the technique, the crystallite orientation in enamel can be determined. A Raman spectrometer based on Fourier transform and a diode-laser-pumped Nd:YAG laser (1.06 mm) can be used to obtain fluorescence-free Raman signals from biological materials, and identification of mineral components present in dental calculus is possible.

Calcium Fluoride↗
PubMed1996

Raman spectra of human dentin mineral.

Human dentin mineral has been investigated by using micro-Raman spectroscopy. Fluorescence and thermal problems were largely avoided by preparing dentin samples by grinding and ultrasonic agitation in acetone. The Raman spectral features were consistent with those of impure hydroxyapatite containing CO3 and HPO4. While spectral differences between enamel and dentin were clearly observable as changes in the bandwidth of the PO4(3-)V1 band and the intensities of the OH-, CO3(2-) and HPO4(2-) bands, the technique could not detect spectral differences between coronal and root dentin. NaOCl, NaF and APF-gel treatments caused measurable changes in intensities of the bands due to CO3(2-) and HPO4(2-); the results were found to be useful for band assignments. After NaOCl treatment, the Raman bands, presumably due to amide and HPO4(2-), were lost, but the band intensity of the CO3(2-)V1 bands increased by 35-60%. This increase coincided with the appearance of a new broad band (250-300 cm-1). The same treatment on enamel caused no increase in the CO3(2-)V1 band intensity. This NaOCl-induced carbonate could be removed within 20 h in a 1000 ppm NaF solution. These findings indicate that the carbonate ions induced by the NaOCl treatment are presumably in or on the mineral surface. After 3 min of APF-gel treatment on NaOCl-pretreated dentin, the intensities of the hydroxyapatite phosphate bands dropped by approximately 20%, and newly formed CaF2 and HPO4 bands became observable.

Acidulated Phosphate Fluoride↗
PubMed1996

Microradiography and confocal laser scanning microscopy applied to enamel lesions formed in vivo with and without fluoride varnish treatment.

The aim of the present investigation was to combine 2 techniques suitable for lesion characterization: quantitative microradiography (TMR) and confocal laser scanning microscopy (CLSM) on in vivo induced lesions with and without a fluoride varnish (Duraphat) treatment. Orthodontic bands were attached to premolars to be extracted for orthodontic reasons to induce enamel caries on the buccal surfaces. In the caries development part of the study, 1 tooth of each pair received at the start 1 topical application with the fluoride varnish Duraphat, the contralateral tooth serving as untreated control. All teeth were extracted after 4 weeks. In the caries progression part, the premolars were banded for 4 weeks without any treatment to induce caries, 1 premolar in each pair was then extracted and analyzed. The contralateral tooth received one Duraphat application and was extracted after another 2 weeks. In the caries development part of the study, TMR analysis showed that the Duraphat treatment on sound enamel reduced lesion depth by 48% compared to the untreated control. In the caries progression part, no significant difference was found between the untreated teeth extracted after 4 weeks and the fluoride treated lesions extracted after another 2 weeks. CLSM images agreed well with the TMR measurements. In the fluoride treated lesions, the CLSM images showed more light scattering indicating precipitation of material.

Adolescent↗
PubMed1996

Effect of sodium hypochlorite treatment on remineralization of human root dentine in vitro.

Dentine consists simplified of mineral and of several organic components. Sodium hypochlorite (NaOCl) is a well-known nonspecific proteolytic agent capable to remove organic material. The aim of this study was to investigate the influence of organic material removal from artificial dentine lesions by means of NaOCl pretreatment on subsequent remineralization with and without fluoride. Human root dentine samples were demineralized in an acidic gel (pH = 5) at 37 degrees C for 2 weeks. After 2 min of pretreatment with a 0.4, 2 or 10% NaOCl solution, the samples were remineralized in a 20 mM HEPES buffer (pH = 7) containing 1.5 mM Ca(2) and 0.9 mM phosphate with or without addition of 10 ppm F(-) as NaF at 37 degrees C for 8 days. Mineral profiles were assessed by means of transversal microradiography after diol treatment to avoid shrinkage caused by drying. In a separate experiments the dentine contraction caused by 10% NaOCl was assessed. The contraction (negligible for sound dentine) was found to be about 12% for the lesions. The remineralization results showed that pretreatment with a 10% NaOCl solution for 2 min, increased lesion remineralization. After NaOCl treatment, the amount of accumulated mineral increased by about 27% without F in the remineralization solution, and by about 4% with 10 ppm in solution. The in vitro results suggest that removal of organic materials from dentine lesions is an interesting approach to enhance remineralization.

Adolescent↗
PubMed1996

Evaluation of sodium fluorescein for quantitative diagnosis of root caries.

The diagnosis of root caries, in particular the judgment of the activity of a visually observed lesion, is difficult. Quantitative determination of lesion severity would allow the lesion to be monitored with time, so that an indication of lesion activity could be obtained. This paper describes a step in the development of a method that provides such a quantitative determination. Specifically, fluorescein sodium salt is used as a penetrating dye, the subject of study being the relationship between dye concentration and porosity in demineralized root dentin. Fourteen human third molars were demineralized in vitro (lactic acid CMC-gel, pH 5; in each of 6 groups for 4, 7, 11, 14, 18, and 21 days). Fluorescein sodium salt (0.2 g/L) was applied for 2 min. Thin slices (+/- 130 microns) were cut from the root surfaces without water cooling. The dye fluorescence radiance in the demineralized dentin was determined by means of a micro-Raman spectroscope and compared with the mineral loss profiles measured with transverse microradiography (TMR). The TMR data were corrected for the difference in measurement area between the two measurement systems. Corrected TMR profiles were compared with the corresponding fluorescence scans, showing linear correspondence. The correlation coefficient was r = 0.96. We conclude that, after uptake of fluorescein sodium salt for 2 min, the dye concentration in an artificially produced root-surface caries lesion is proportional to the amount of mineral lost from that lesion.

Dentin↗
PubMed1996

Use of tetranectin, CA-125 and CASA to predict residual tumor and survival at second- and third-look operations for ovarian cancer.

Tetranectin (TN), CA-125 and CASA were measured in serum prior to 63 second-look and 5 third-look operations for ovarian cancer. Patients with residual tumor had significantly lower levels of TN and higher levels of CASA and CA-125 compared with tumor-free patients. The predictive values PVPos = 100% and PVNeg = 50.9% were found for TN at 9.3 mg/l. For CASA, a predictive value PVPos = 100% was found at 10 U/ml with a corresponding PVNeg = 52.7%. At the cut-off 35 U/ml for CA-125, the PVPos was 100% and the PVNeg = 53.6%. By combining the markers, PVNeg increased to 61.7% with a PVPos on 100%. Significantly differences in survival were found by lifetable analysis between patients tested as positive and negative respectively for any of the markers. Using multivariate Cox analyses, it was found that every marker had an independent prognostic function for survival.

Adult↗
PubMed1996

Instruments and methods for the quantitative measurement of factors affecting hygienist/dentist efforts during scaling and root planing of the teeth.

Manual calculus debridement through scaling accounts for a significant proportion of hygienist efforts in dental and periodontal practices. Despite this, little is quantitatively known concerning the effects of instruments, technique and treatments on debridement (scaling) efficiency or efficacy. The total work effort expended by therapists in calculus debridement results from the sum of the efforts associated with each scaling stroke. Each scaling stroke, in turn, is affected by a variety of physical forces, including those in the control of the therapist and those intrinsic to the calculus substrate. The development of procedures and treatments to facilitate easier calculus removal requires consideration of the physical and technique-related factors which contribute to hygienist effort. Instruments have recently been developed which can quantitatively measure force dynamics associated with scaling procedures, including both therapist-applied forces and forces developed due to the extreme hardness and tenacity of supra- and subgingival calculus deposits. The scaling instrument developed to quantitatively record developed forces in scaling, the Quanticalc, can be used for the assessment of techniques and treatments which can soften calculus, facilitating easier debridement. The device can also be used to instruct therapists on factors contributing to surface roughness and tactile response to these factors. The scaling instrument developed to quantitatively measure therapist applied forces in scaling, the Zappa device, can be used for assessment of techniques which can increase the efficiency of calculus removal with minimal damage to sound root substance. In this paper, the force dynamics associated with manual scaling procedures of dental professionals are defined. These force dynamics account for the total work expended by hygienists and other professionals in the important task of calculus removal. Using this as a foundation, the design, use, calibration and clinical applications of these newly developed scaling-force measurement systems are described.

Algorithms↗
PubMed1996

Crest Tartar Control benefits assessed by Quanticalc: clinical method and three-month results.

In this paper, a method is described for applying the Quanticalc (QC) dental scaler to the clinical assessment of tartar control dentifrice effects on supragingival calculus formation and therapist efforts required in subsequent calculus debridement. In a 3-month, randomized cross-over study, subjects using Crest Tartar Control were observed to form 25% less calculus than they formed in a similar period using Crest Regular non-tartar control dentifrice as placebo. QC measurements likewise revealed 25% savings in the developed force used to scale the anterior lingual surfaces, coupled with a 27% reduction in the number of strokes required to clean these surfaces free of supragingival calculus in subjects using tartar control dentifrice. The quantitative savings in professional effort amounted to 3 kg (developed forces saved) per subject using tartar control dentifrice. White subjects using placebo dentifrice for 3 months developed less calculus than shown at baseline (29% less calculus), this was not complemented by decreases in total force and strokes used in cleaning. This supports the hypothesis that the surface area coverage of calculus (e.g., the planimetric "area" of supragingival calculus on the tooth) does not contribute alone to the amount of effort as forces and strokes required in subsequent debridement. These results demonstrate that: 1) the QC dental scaler can be effectively used in the clinical assessment of scaling forces/efforts associated with supragingival calculus debridement; and 2) a tartar control dentifrice containing soluble pyrophosphate is clinically effective in reducing both the surface coverage of calculus and the therapist effort required in subsequent calculus debridement.

Adult↗
PubMed1996

Quanticalc assessment of the clinical scaling benefits provided by pyrophosphate dentifrices with and without triclosan.

The Quanticalc (QC) dental scaler permits a quantitative assessment of the work used by professionals in calculus removal through the measurement of force dynamics and scaling strokes applied in calculus debridement. The purpose of this study was to use the QC to compare the clinical effects of two 5% pyrophosphate dentifrices on dental calculus in subjects following six-months' product use. Three-hundred forty-six subjects participated in a six-month, double-blind tartar control clinical trial involving traditional Volpe-Manhold Index (VMI) evaluations. Following the six-month VMI examinations, the subjects had a QC prophylaxis (scaling force measurements). The three dentifrice treatment groups included a control dentifrice (NaF only, Crest); NaF dentifrice containing 5.0% pyrophosphate (Crest Tartar Control); and NaF dentifrice containing 5.0% pyrophosphate plus 0.28% triclosan (antimicrobial). Subjects were balanced by baseline (pretest) VMI scores at the start of the trial. QC examinations revealed statistically significant reductions in total force and stroke number used by the therapist to scale the six anterior VMI teeth for subjects using the pyrophosphate tartar control dentifrices as compared to control dentifrice. The reduction in scaling effort amounted to almost 3 kg per scaling for subjects. QC results paralleled VMI reductions of calculus on the teeth and demonstrated that the use of 5% pyrophosphate dentifrices, with or without triclosan antimicrobial, results in significant reductions in the total (developed) force and strokes required by therapists in regular calculus debridement at a six-month interval. The clinical benefits of tartar control toothpastes may not only include reductions in cosmetically objectionable supragingival calculus, but in reducing professional effort in calculus debridement during regular prophylaxis.

Analysis of Variance↗
PubMed1996

Effects of a scaling gel on forces developed in debridement of supragingival calculus determined by means of a transducer-modified dental scaler: the Quanticalc.

The efficacy of a calculus scaling gel, SofScale (Dentsply, York, PA), has been examined in two protocols by the measurement of scaling forces developed in supragingival calculus debridement from the anterior dentition using hand scaling with a transducer-modified dental scaler, the Quanticalc. In one protocol, the effects of the scaling gel were compared to a placebo gel composed of conventional toothpaste in a double-blind, split-mouth design. In another protocol, the effects of the scaling gel were determined in comparison to non-treated calculus. Results demonstrated that the scaling gel had no apparent effects on the physical forces (work) involved in calculus removal. These results suggest that the application of the scaling gel provides no quantitative benefits in facilitating calculus debridement during manual tooth scaling.

Analysis of Variance↗
PubMed1996

A Quanticalc clinical comparison of professional efficiency in manual supragingival calculus debridement.

The Quanticalc (QC) dental scaler permits the assessment of work effort expended by professionals in removing supragingival calculus from the teeth. The purpose of this study was to compare the efficiency of two professionals in scaling calculus under controlled clinical conditions in like populations. One-hundred and thirty-one subjects were randomly assigned to two professionals, A and B, for QC scaling of their six Volpe-Manhold Index (VMI) teeth. VMI assessments were carried out by a separate examiner prior to QC cleaning. The QC was used to record total developed force, total strokes and force/stroke used in calculus debridement. Results demonstrated significant differences in scaling efficiency between the two professionals. These results further demonstrate the potential utility of the QC and like devices in assisting in the instruction of professionals toward the development of more efficient manual scaling procedures.

Analysis of Variance↗