摘要:

The present report aimed at evaluating the influence of recording conditions on the relative uptake of direct motor responses obtained in the masseter and tempo‐rails muscles after electrical stimulation of their nerves, using a monopolar needle technique. In 10 subjects, various surface electromyographic recording set‐ups were compared using supramaximal M‐responses. Volume‐conducted potentials originating from the masseter muscle could be recorded from the neck. For the masseter muscle, the optimal position for the active recording electrode was over the anterior and inferior part of the muscle belly. The configuration of the masseter M‐response recorded from various positions over the muscle belly was highly variable both intra‐ and interindividually. The configuration of the M‐response of the anterior part of the temporalis muscle showed les

ISSN:0909-8836    

DOI:10.1111/j.1600-0722.1995.tb01855.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

The effects of the antihypertensive drug captopril on salivary secretion rate and composition was evaluated in 24 healthy adults (18–46 yr) according to a double‐blind, cross‐over design. Unstimulated and paraffin‐chewing stimulated whole saliva and 3% citric acid stimulated parotid and submandibtilar‐sublingual (SM‐SL) secretion were collected at 10.30 a.m. (about 2h after intake of breakfast) on day 0 (baseline values), day 1 (experimental acute values) and day 7 (experimental chronic values) in each treatment period. In 8 of the subjects, also morning samples were collected at 7.30 a.m., with the test subjects in a fasting condition. Whole saliva was assessed for flow rate and for concentrations of sodium, potassium, chloride, calcium and phosphate. In addition, parotid and SM‐SL secretion were assessed for concentrations of total protein, hexosamine. sialic acid, lactoferrin and salivary IgA and for activities of amylase. lysozyme and salivary peroxidase. During treatment with the angiotensin converting enzyme inhibitor captopril, the secretion rates tended to increase for unstimulated and paraffin‐chewing stimulated whole saliva and for parotid secretion. For salivary composition, no alterations were observed in any of the colle

ISSN:0909-8836    

DOI:10.1111/j.1600-0722.1995.tb01856.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

The aim of this double‐blind study was to enumerate the total number of living and dead bacteria on defined tooth areas during the application of antibacterial mouthrinses. After prophylaxis, 40 students refrained from all oral hygiene measures for 3 d, during which they rinsed with a phenolic compound (Listerine), an amine fluoride/stannous fluoride solution (Meridol), 0.2% chlorhexidine (CHX) or a control solution (0.02% quinine‐hydrochloride). The plaque index (PII) was recorded at the start and the end of the investigation. Total bacterial counts (BC) and colony‐forming units (CPU) of 1d‐, 2d‐ and 3d‐old dentogingival plaque were determined. The plating efficiency (PE) was calculated as a percentage of CFU/BC and the portion of vital microflora estimated by a vital fluorescence technique (VF). All groups started with a P1I approximating 0.1. On day 3, the P1J values were 1.21 in the control group and 0.51, 0.37 and 0.14 after Listerine, Meridol and CHX use, respectively. A tremendous variation existed between the numbers of viable bacteria found per mm‐ on the enamel surface on day 3 (CHX: 0.2: Meridol: 300; Listerine: 6×104; control: 2×106). while higher total numbers of bacteria were concomitantly present (CHX and Meridol: 1–2×104; Listerine: 2×105: control: 2×106). Both vitality parameters PE and VF reached 92% in the control group at day 3, but only 7% after CHX use. With Meridol and Listerine, the corresponding PE values were 3% and 43%, respectively, while the VF values reached 48% and 54%. The P1I, BC, CFU and PE values of the CHX and the Meridol groups differed significantly from those of the control group. In contrast, Listerine showed no difference as compared to the control rinse. Due to the strong antibacterial action of CHX and Meridol during their use, almost only dead or non‐proliferating bacteria were found on the tooth surfaces. Thus, only a thin plaque could develop. As a clinical consequence, both substances showed retardation of plaque development as reflected by significantly

ISSN:0909-8836    

DOI:10.1111/j.1600-0722.1995.tb01857.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

F‐dentifrice usage causes slightly elevated fluoride levels in saliva. Therefore, the effects of permanent low fluoride concentrations versus daily dentifrice treatments were studied on enamel and dentin lesions in a pH‐cycling model of alternating demineralization and remineralization. Groups received 1) no fluoride treatment. 2) 3 μM (0.06 ppm) F continuously present during re‐ and demineralization or 3) daily 5–min F‐dentifrice treatments. Solutions were analyzed for changes in calcium and fluoride. Cumulative results (10 d) showed that for the non‐fluoride group the dentin lesions increased, while for enamel lesions mineral uptake and loss were balanced. Addition of 3 μM F caused small, non‐significant, enhancement of remineralization (1–7%). while demineralization was significantly inhibited for both tissues (9–23%). The daily dentifrice treatments resulted in a balance between mineral uptake and loss of dentin, due to inhibited demineralization (‐33%) and enhanced remineralization (+ 79%). For enamel, the F‐dentifrice treatments resulted in 43% reduction of demineralization, with no significant effect on remineralization. Fluoride loss from the 3 μM F cycling solutions was significant (up to 50%) and constant during the experimental period. Microradiographic analysis showed remineralization at the lesion front in enamel. In dentin, the lesion depth was increased in all groups, with concomitant mineral deposition in the surface region of the dentifrice group. Results indicate that slightly elevated fluoride levels may be considerably less effective in inhibiting lesion progression in dentin than in enamel, and suggest mineral uptake and loss to occur at similar depths for enamel lesions, while demineralization and remineralization occur at di

ISSN:0909-8836    

DOI:10.1111/j.1600-0722.1995.tb01858.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

The effects of a 10% NaOCl treatment for 2 min on demineralized human root dentin were investigated by means of: microradiography (MR), scanning electron microscopy (SEM), confocal laser scanning microscopy (CLSM) and secondary ion mass spectroscopy (SIMS). MR measurements revealed that NaOCl caused a tissue contraction not related to water loss but to removal of organic sub‐stance(s), resulting in reductions of the lesion depth and mineral loss values by 15% and 42%, respectively. CLSM observations on wet dentin showed that the dentinal tubules underneath the surface are clearly observable and not deformed substantially by the NaOCl, except near the outermost surface. This indicates the importance of wet as well as of dried (high vacuum) observations. SEM micrographs (high vacuum) showed definite changes in the outer dentin surface structure, 85% of the originally open dentinal tubules were closed after NaOCl treatment. No marked changes were observed in the dentin ultrastructure inside lesions, as shown by SEM on fractured surfaces. SIMS data, pertaining to samples in high vacuum, showed a remarkable increase of chlorine (Cl) content in the entire lesion due to the NaOCl, indicating deep penetration of the original OC1 ions. The results suggest that the 2‐min treatment of demineralized dentin by NaOCl solutions removes and/or changes part of the dentin matrix in nearly the whole lesion. As a consequence the mineral is somewhat redistributed, the outermost surface of a few μm is changed, but the main dentin structure and element composition are still intact. These findings indicate that NaOCl treatments are of interest in remineralization and hyperremineralization studies of de

ISSN:0909-8836    

DOI:10.1111/j.1600-0722.1995.tb01859.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

The aim of this paper is to report on the demineralization‐induced changes in dentin autofluorescence. Confocal laser scanning microscopy (CLSM) images and fluorescence excitation and emission spectra ofin vitrodemineralized root surfaces and sound controls on the same tooth roots were compared. When observed in CLSM images, demineralized dentin, excited at 488 nm. gave an increased emission at 529 nm compared to sound dentin. The difference in fluorescence decreased deeper into the root, as the sound dentin underneath the lesion was reached. In contrast, when using fluorescence spectrophotometry, excitation around 460 and 488 nm yielded a lower emission around 520 nm for demineralized dentin than for sound dentin, but in a more pronounced peak. From excitation spectra for emission around 520 nm. it could be seen that in demineralized dentin the contribution of excitation between 480 and 520 nm was more important than in sound dentin. The recorded fluorescence in CLSM images was not affected by demineralization‐caused changes in scattering and absorption properties, due to the small measurement volume. Thus, the increased fluorescence for demineralized dentin implies an increased quantum yield. In fluorescence spectrophotometry. where the measurement volume is large, changes in scattering and absorption do have an influence on the fluorescence signal. Then, increased absorption by non‐fluorescing chromophores and increased re‐absorption around the emission wavelength may compensate for the increase in quantum yield and absorption around the excitation wavelength by fluor

ISSN:0909-8836    

DOI:10.1111/j.1600-0722.1995.tb01860.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

Titanium granules were tested for their antibacterial effect on strains ofStreptococcus sanguis. Streptococcus mitis, Actinomyces naeslundii, Haeinophilus parainfluenzae, Fusobacieriumspp. andPrevotella intermediain comparison with amalgam and two of its components, copper and tin. Glass beads were used as controls. The number of viable bacteria was estimated in samples exposed to the various materials for 1, 3, 6 and 24 h, respectively, and the viable counts were related to the baseline value. Titanium showed low antibacterial effect on the species tested. Copper and amalgam showed an expressed toxicity to all species and differed significantly from titanium and glass particles. Gram positiveStreptococcusspp. andA. naeslundiishowed a lower susceptibility to the metals than the Gram negative species, The antibacterial effect of copper and amalgam test particles onS. sanguisandP. intermediawas significantly decreased in the presence of serum. This study showed that some metals have a toxic effectin vitroon oral bacteria, a fact that may play a role in plaque formation when these materials are used for dental restorations. Titanium did not have a similar antibacterial effect.

ISSN:0909-8836    

DOI:10.1111/j.1600-0722.1995.tb01861.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

The purpose of this study was to investigate the condensation pressure during amalgam placement in patients. Forty‐four practitioners were asked to fill two class 2 cavities in the lower jaw on their patients in their own practice with the aid of a force‐measuring plugger. This device, with semiconductor strain gauges, allowed the dentist to have an identical tactile feedback as with any other plugger. Three different amalgams, with different shapes of alloy particles, were tested. The results showed a maximum condensation pressure of 8.9±2.4 MPa and 5.5±1.8 MPa with a small and a large amalgam plugger, respectively. Average condensation pressures were 3.7±1.3 MPa for the small and 2.2±0.9 MPa for the large instrument. The total working time required to fill a cavity was on average 131 s; the amalgam was effectively condensed for 44 s. No significant differences between amalgams with different shapes of alloy particles, no influence of time of day, and no difference between female and male dentists were found. This study showed that the condensation pressure is lower than often recommended, and that it is not statistically different from the values obtained in a previous laboratory st

ISSN:0909-8836    

DOI:10.1111/j.1600-0722.1995.tb01862.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

The quality of visible‐light‐cured composites depends on the capability of the light source to properly polymerize the material within a specified exposure lime. In this study, the degree of conversion of different composite materials (hybrid and microfilled) of light and dark shades was compared after illumination by a standard curing unit and pulsed laser (γ=468) respectively. The degree of conversion was measured by Fourier transform infrared spectroscopy. Results obtained by the analysis of the pulsed laser‐induced polymerization were significantly higher for all the materials and shades observed. All values of the degree of conversion were lower for dark shades of all types of composites, regardless of the photopolymerization technique used. Besides the surface, better polymerization was recorded also at depths of 1.0. 2.0 and 3.0 mm, respectively. These values varied from 59.7%±2.14 to 84.5%±0.33 for pulsed laser (including all depths) caused by the saturation effect induced by high power laser pulses and from 42.7%±1.48 to 74.7%±0.99 for standard poly

ISSN:0909-8836    

DOI:10.1111/j.1600-0722.1995.tb01863.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

The aim of this study was to compare two different modes of behaviorally‐oriented therapies for dental fear. The subjects were chosen consecutively from the waiting‐list of a Dental Fears Research and Treatment Clinic. In addition, a control group was selected from patients treated under general anesthesia to compare levels of dental and general fear with the experimental groups. Twenty‐two women, with a mean age of 31.8 yr, were included and randomly assigned to two groups. The median time of avoidance of dental care was 9.5 yr. One group received hypnotherapy (HT) and one group a behavioral treatment based on psychophysiological principles (PP). Both therapies included eight sessions followed by standardized conventional dental test treatments. Pre‐ and posttreatment measures were dental fear, general fear. mood, and patient behavior. Nine patients were not able to conclude the treatment sessions (6 HT and 3 PP); these patients did not differ significantly from the remaining patients before treatment. The PP group reported a statistically significant decrease in dental fear as well as a rise in mood during dental situations, as opposed to the HT group. General fear levels decreased but not significantly. Eleven patients completed conventional dental treatment according to a dentist's behavioral rating scale, indicating that they were relaxed, and no problems occurred during the treatments. These patients were referred to general practitioners within the community dental service. In conclusion, this small size study showed that a majority of the patients, who accomplished the behavioral therapy and the dental test treatments, became less fearful of dental care and were able to manage conventional dental care, including changing

ISSN:0909-8836    

DOI:10.1111/j.1600-0722.1995.tb01864.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY