bluuebunny/crossref_metadata_2025 huggingface dataset:
Adrenomedullin Acts in the Rat Paraventricular Nucleus to Decrease Blood Pressure
Authors: Smith P. M. , Ferguson A. V.
Published: March 2003

Adrenomedullin is a recently discovered peptide involved in the control of fluid and electrolyte homeostasis and cardiovascular function through peripheral and central nervous system actions. The present study was undertaken to examine the cardiovascular effects of adrenomedullin microinjection directly into the paraventricular nucleus (PVN). Microinjection of adrenomedullin into the PVN of urethane anaesthetized male Sprague‐Dawley rats resulted in site‐specific, repeatable decreases in blood pressure. These hypotensive effects were found to be dose related, and were not mediated by activation of calcitonin gene‐related peptide receptors. These data suggest that adrenomedullin influences cardiovascular regulation through receptor mediated actions at the PVN of the hypothalamus.
The Effect of Acute and Chronic Restraint on the Central Expression of Prepro‐Neuropeptide Y mRNA in Normotensive and Hypertensive Rats
Authors: Sweerts B. W. , Jarrott B. , Lawrence A. J.
Published: March 2003

Neuropeptide Y (NPY), one of the most abundant neuropeptides found in the central nervous system (CNS), has been implicated in the regulation of many autonomic functions, including cardiovascular control and the central stress response. The present study represents a detailed investigation of the effects of acute and chronic restraint stress on the expression of the mRNA encoding the NPY precursor, prepro‐NPY, in the CNS of normotensive Wistar‐Kyoto (WKY) rats and spontaneously hypertensive rats (SHR) using in situ hybridization histochemistry. Basal (unstressed) levels of prepro‐NPY mRNA expression were found to be significantly increased in the hypothalamic arcuate nucleus of SHR compared to WKY rats, with similar levels of prepro‐NPY mRNA expression found in the remaining central nuclei. Following exposure to both acute and chronic restraint, significant changes in prepro‐NPY mRNA expression were found in a variety of central regions in both strains, including the arcuate nucleus and hippocampus (both strains), medial amygdala and cortex (WKY only), and dentate gyrus, nucleus of the solitary tract and ventrolateral medulla (SHR only). A comparison of the temporal response to restraint revealed that significant differences between strains existed in regions such as the arcuate nucleus, hippocampus and dentate gyrus, providing further evidence that hypertensive rats apparently have an impaired neural stress response. The present study demonstrates that exposure to restraint results in significant changes in prepro‐NPY mRNA expression in specific nuclei of both WKY and SHR that are components of not only the central circuitry regulating the stress response, but also the neural network modulating autonomic function.
Butyl Benzyl Phthalate, an Endocrine Disrupter, Inhibits Pulsatile Luteinizing Hormone Secretion Under an Insulin‐Induced Hypoglycaemic State in Ovariectomized Rats
Authors: Kawaguchi M. , Funabashi T. , Aiba S. , Kimura F.
Published: March 2003

Butyl benzyl phthalate (BBP) and bisphenol A (BPA), termed endocrine disrupters, are known to mimic oestrogen in their actions, and therefore there is concern about their effect on reproductive functions. Since it is reported that the inhibitory action of oestrogen on the pulsatile secretion of luteinizing hormone (LH) is enhanced under insulin‐induced hypoglycaemia, whether this also applies to BBP and BPA was examined in the present study. In adult ovariectomized (OVX) rats, the pulsatile LH secretion 24 h after subcutaneous injection of 10 mg BBP (BBP‐treated), 10 mg BPA (BPA‐treated) or 100 ng 17β‐oestradiol (E2‐treated), all of which were dissolved in sesame oil, was not changed significantly compared to that after the injection of sesame oil only. Furthermore, in oil‐treated OVX rats, the pulsatile LH secretion immediately after intravenous injection of insulin (1.0 U) was not changed compared to that after saline injection. In BBP‐treated OVX rats, the injection of insulin (1.0 U) significantly decreased the number of LH pulses as in E2‐treated OVX rats. The injection of insulin did not significantly affect the amplitude of LH pulses in BBP‐, BPA‐ and E2‐treated OVX rats. The results indicate that the oestrogenic action of BBP is significantly enhanced by insulin‐induced hypoglycaemia and thus the pulsatile LH secretion is inhibited. We suggest that weak oestrogenic endocrine disrupters may become harmful to reproductive functions even in adult female rats, if acting under a low energy state.
Overexpression of the V3 Vasopressin Receptor in Transgenic Mice Corticotropes Leads to Increased Basal Corticosterone
Authors: René P. , Grino M. , Viollet C. , Videau C. , Jullian E. , Bucchini D. , Epelbaum J. , Bertagna X. , De Keyzer Y.
Published: March 2003

The vasopressin V3 receptor (V3) is specifically expressed in pituitary corticotropes and mediates the stimulatory effect of vasopressin on adrenocorticotropic hormone (ACTH) release. The V3 gene is overexpressed in corticotrope pituitary tumours compared to normal pituitaries. We hypothesized that V3 overexpression might induce changes in corticotrope function and alter the regulation of the hypothalamic‐pituitary‐adrenal axis. Thus, we generated transgenic mice (POMV3) expressing the human V3 receptor in the pituitary under the control of rat pro‐opiomelanocortin (POMC) promoter sequences. The transgene was efficiently transcribed and vasopressin binding was increased in both corticotropes and melanotropes. In‐vitro ACTH release and inositol phosphate formation were unchanged in POMV3 pituitaries, but the responses to vasopressin were significatively increased. In vivo, basal circulating concentrations of ACTH in POMV3 mice were similar to those of controls but corticosterone concentrations were moderately increased. In addition, the levels of POMC mRNA in the transgenic pituitaries were comparable to those of control mice. Finally, POMV3 mice responded with a similar maximal increase of ACTH and corticosterone to a 20‐min acute restraint stress. Together, these results show that hypophyseal V3 overexpression led to increased basal concentrations of corticosterone and suggest that the negative glucocorticoid feedback may be altered at the pituitary level.
Functional Cooperation Between Neurosteroids and D2 Dopamine Antagonists on KCl‐Evoked [3H]Noradrenaline Release: Modulation By Calcium Channel Blockers
Authors: Monnet F. P.
Published: March 2003

It has recently been proposed that neurosteroids, such as dehydroepiandrosterone sulphate and pregnenolone sulphate, interfere with the dopamine system in the central nervous system. According to our previous report showing that the butyrophenone, spiperone, slightly enhances the evoked release of [3H]‐noradrenaline ([3H]NA) in the presence of these sulphated steroids, the present study was carried out to document the putative interplay between steroids and spiperone, which is known to be a prototypic D2 dopamine antagonist and also a 5‐HT2 serotonin antagonist. For this purpose, the paradigm of KCl‐evoked [3H]NA release from preloaded rat hippocampal slices was used to investigate the interactions between neurosteroids, spiperone and the voltage‐sensitive calcium channels (VSCCs). The selective 5‐HT2 serotonin antagonist ritanserine was ineffective, whereas sulpiride, a selective D2 dopamine antagonist mimicked the action of spiperone, thus suggesting that the blockade of D2 dopamine receptors accounted for the modulatory effect of spiperone on neurosteroid‐induced modulation of evoked [3H]NA release. In addition, this facilitation of KCl‐evoked [3H]NA release by the combination of a steroid and a D2 dopamine antagonist was partially inhibited by the L‐ and N‐type VSCC blockers nifedipine and ω‐conotoxin GVIA, respectively. The present results provide in‐vitro functional evidence for the putative role of VSCCs in the interplay between steroids and D2 dopamine receptors.
Effect of Direct Injection of Melanin‐Concentrating Hormone into the Paraventricular Nucleus: Further Evidence for a Stimulatory Role in the Adrenal Axis via SLC‐1
Authors: Kennedy A. R. , Todd J. F. , Dhillo W. S. , Seal L. J. , Ghatei M. A. , O'Toole C. P. , Jones M. , Witty D. , Winborne K. , Riley G. , Hervieu G. , Wilson S. , Bloom S. R.
Published: March 2003

Melanin‐concentrating hormone (MCH) is implicated in the control of a number of hormonal axes including the hypothalamic‐pituitary adrenal (HPA) axis. Previous studies have shown that there is evidence for both a stimulatory and an inhibitory action on the HPA axis; therefore, we attempted to further characterize the effects of MCH on this axis. Intracerebroventricular injection of MCH increased circulating adrenocorticotropic hormone (ACTH) at 10 min post injection. Injection of MCH directly into the paraventricular nucleus (PVN) was found to increase both circulating ACTH and corticosterone 10 min after injection. Additionally, MCH was found to increase corticotropin‐releasing factor (CRF) release from hypothalamic explants, and this effect was abolished by the specific SLC‐1 antagonist SB‐568849. Neuropeptide EI, a peptide from the same precursor as MCH was also found to increase CRF release from explants. These results suggest that MCH has a stimulatory role in the HPA axis via SLC‐1, and that MCH exerts its effects predominantly through the PVN CRF neuronal populations
Lengths of condylar pathways measured with computerized axiography (CADIAX®) and occlusal index in patients and volunteers
Authors: Gsellmann B , Schmid‐schwap  , Piehslinger  , Slavicek
Published: March 2003

The lengths of the condylar pathways during protrusive and opening movements were investigated with computerized axiography in 100 individuals. Forty‐two patients suffering from anterior disk displacement with reduction (ADD) in one or both temporomandibular joints (TMJ) and 28 patients with anterior overrotation clicking (AOC) of the TMJ were compared with 30 asymptomatic volunteers. Patients suffering from ADD showed significantly shorter tracings than did the two other groups. A significant difference of length of TMJ movement between men and women was found only in one group. The occlusal indices (OI) of the three groups were assessed and compared with each other. Here, a significant difference was found between volunteers and patients suffering ADD and between volunteers and patients with AOC. Between men and women a significant difference of the OI was found in the group with AOC, women presenting higher scores than men. Except for the group of patients with ADD, who showed shorter average lengths, volunteers as well as patients with AOC, were within the normal limits given in the literature for TMJ movement lengths recorded with axiography. The results of this examination therefore indicate that when considering movement length alone no discrimination between healthy and diseased TMJ can be made.
The masticatory–parotid salivary reflex in edentulous subjects
Authors: Scott  , Hassanwalia  , Linden
Published: March 2003

The parotid–masticatory salivary reflex has been studied in edentulous subjects. Salivary flow was recorded by siting a modified Lashley cup over the orifice of the parotid duct on one side of the mouth. Subjects chewed on small pieces of silicone rubber with their complete dentures for 1 min periods which resulted in a reflex secretion of parotid saliva. The secretion was greatest when the subject chewed on the same side of the mouth (ipsilateral) as the salivary flow was recorded. Less salivary flow resulted when the subjects chewed on the opposite side of the mouth (contralateral). Anaesthesia of the mucosa of the maxillary and mandibular denture‐bearing area was achieved by placing a thin layer of anaesthetic ointment in the fitting surface of the dentures on the side ipsilateral to the Lashley cup. This resulted in a reduction of salivary flow in response to similar chewing cycles. The results confirmed the presence of a parotid–masticatory salivary reflex in edentulous subjects which appears similar in many respects to that of dentate subjects. It is likely that receptors in the oral mucosa are stimulated when an edentulous subject masticates with complete dentures and that activity in these mechanoreceptive neurones results in the reflex salivary secretion.
The effect of dental alloys on mouse lymphocyte subpopulations
Authors: Zalkind  , Calderon  , Rabinowitz  , Hadar  , Schlesinger
Published: March 2003

The aim of the present study was to determine the effect of nickel‐containing alloys on lymphocyte subsets in an experimental setting. Plates of alloys containing nickel (Ceramalloy, Talladium, Cerillium, Rexillium) or gold (Orion) were implanted subcutaneously into mice. The levels of CD4+ and CD8+ T‐lymphocyte subpopulations and of Smig+ B lymphocytes were determined at various intervals following implantation, using monoclonal antibodies and flow cytometry. No changes were detected in the proportion of the lymphocyte subsets tested. One month after implantation, the mean fluorescence intensity of CD4, CD8 or Smig, in the peripheral blood lymphocytes (PBL) of the nickel alloy‐implanted animals, was significantly higher than that prior to this procedure. Only a mild increase in CD4 and CD8 was noted after implantation of the gold alloy. The observed effects are most likely attributable to the surgical trauma, and do not indicate that nickel‐containing dental alloys influence T cell subsets in this murine model.
The analysis of frequency of occlusal sounds in patients with periodontal diseases and gnathic dysfunction
Authors: Heûdzelek  , Hornowski
Published: March 2003

A study is presented of occlusosonograms obtained from healthy subjects and patients with periodontal diseases and gnathic problems. Gnathosonic examinations were carried out by means of a set of equipment whose basic elements were two piezoceramic transducers mounted on a specially made holder and an IBM PC with an ADC card. The evaluation of occlusosonograms was by means of mathematical analysis of the frequency pattern. In pathological stages, the occlusosonograms exhibit more high frequency components. In the case of healthy subjects, the recorded signal took the form of a strong impact of low frequencies and its subsequent exponential decay.
Self‐assessed masticatory ability in relation to maximal bite force and dental state in 80‐year‐old subjects
Authors: Tsuga K. , Carlsson G. E. , Österberg T. , Karlsson S.
Published: March 2003

By means of a questionnaire, clinical examination and force recordings, the relationships between self‐assessed masticatory ability, dental state and bite force were studied in 160 80‐year‐old persons, 74 men and 86 women. The subjects were in general satisfied with their masticatory ability and 70% had no problems, while 6% reported three or more problems with mastication. Half of the subjects were dentate without removable prostheses and almost one‐third had 20 or more natural teeth. The edentulous persons (about one‐fifth of all) reported more problems related to mastication than the other dentition groups. The maximal bite force varied much and exhibited a significant correlation to the number of remaining teeth and dental state. The self‐assessed masticatory ability was only weakly correlated with dental state and bite force. It was concluded that many subjects with few or no remaining teeth and/or removable dentures had only few complaints of impaired masticatory function and showed a good adaptation to an impaired dental status and small maximal bite force.
Long‐term strength of aesthetic restoratives
Authors: Frankel N. , Pearson G. J. , Labella R.
Published: March 2003

Glass‐ionomer cements have established an important role in clinical dentistry since their introduction over 20 years ago. More recently, in an attempt to enhance the strength of the material, resin additions have been made to conventional glass‐ionomer cements. This study established the long term flexural strength of two hybrid glass‐ionomer cements, by use of a bi‐axial flexural strength test (Shell test), and compared the values with those obtained for a light curing composite resin and a conventional glass‐ionomer cement. The results demonstrated that those materials with a high resin component relying on polymerization as the main method of setting had a greater initial flexural strength than those with little or no resin addition. Those materials where the glass‐ionomer acid–base reaction provided a substantial contribution to the setting reaction showed an increase in strength as they matured, whereas a decline in strength with time was observed for those materials where the resin setting reaction predominated.
Comparison of the most comfortable mandibular position with the intercuspal position using cephalometric analysis
Authors: Nakai  , Abekura  , Hamada  , Morimoto
Published: March 2003

SUMMARY For evaluation of the most comfortable position (MCP) in edentulous subjects, as decided by mandibular position sense, the MCP was recorded in ten edentulous subjects and compared with the intercuspal position (ICP) of normal dentate persons. It was found that the MCP was at a lower mandibular position than the ICP; the facial height was markedly reduced in the former by a front‐upward rotation of the mandible centering around the condyles. Thus, it has been suggested that the occlusal vertical dimension (OVD) of the MCP in the restored dentition is less than that of the original ICP.
Amalgam alternatives – micro‐leakage evaluation of clinical procedures. Part I: direct composite/composite inlay/ceramic inlay
Authors: Ziskind  , Avivi‐arber  , Haramati  , Hirschfeld
Published: March 2003

This study investigated the degree of dye penetration with three different types of tooth‐coloured restorations. Twenty‐four intact extracted molars were collected. The teeth were immediately stored in water at room temperature. Class II cavity preparations were prepared and restored with three different types of tooth‐coloured restorations: A, composite resin in the incremental technique; B, composite inlay technique; and C, ceramic inlay. Specimens were subjected to 700 cycles of thermal stress. They were than immersed in 2% basic fuchsin dye. The teeth were sectioned in three planes before being ranked as to the amount of dye penetration. The highest score obtained on three plano‐parallel sections was adopted as the representative value. The three groups were compared using the Kruskal Wallis non‐parametric test. Dye penetration was significantly lower at the enamel margins when using the composite inlay system and the incremental technique compared to the ceramic inlay technique. The restorations placed using the composite inlay technique showed less dye penetration than the incremental technique at the dentine margins (P < 0·017).
CMDME (curved mesh diagram of mandibular excursion) method for visualization and diagnosis of mandibular movement
Authors: Hayasaki H. , Nakata S. , Nishijima N. , Okamoto A. , Minematsu K. , Yamasaki Y. , Nakata M.
Published: March 2003

The CMDME (curved mesh diagram of mandibular excursion) method was developed for easy visualization and diagnosis of mandibular movement. This method uses measured mandibular movement to produce a diagram of the range, shape, and inclination of mandibular excursion in three dimensions using any arbitrary landmark of the mandible. First, the mandibular movement of a subject was measured by an opto‐electronic movement analysis system capable of measuring mandibular movement with six degrees‐of‐freedom at a sampling frequency of 100 Hz. For the measurement, the subject was initially instructed to perform four repetitions of mandibular excursion at will, with tooth contact, each lasting 30 s. A total of 12 000 positions of the mandible were thus obtained. Secondly, an attempt was made to match these positions to intersection points (0·1 mm apart) of a CMDME (i.e. mesh) for arbitrary mandibular landmarks with intercuspal position at the origin. The CMDME method can visualize mandibular excursion, and can be used to compare several landmarks, different subjects, or different times. This makes this method an effective diagnostic tool for mandibular movement.
Influence of finishing time on marginal sealing ability of new generation composite bonding systems
Authors: Yap A. U. J. , Ang H. Q. , Chong K. C.
Published: March 2003

Although variation in finishing techniques has been shown to affect microleakage, little research has been published on the influence of finishing time on the marginal sealing ability of new generation composite bonding systems. The objective of the present study was to evaluate the influence of finishing time on the enamel and dentine marginal sealing ability of four new generation composite systems. Two class V preparations, which were solely in enamel or dentine, were made on the buccal surfaces of 96 freshly extracted molar teeth. The teeth were randomly divided into four groups of 24 and restored with composite resin (Silux Plus®) utilizing the following bonding systems: Scotchbond Multi‐purpose®, Fuji Bond LC®, Prime & Bond 2·0® and Bisco One‐step®. Half of the restorations in each group were finished immediately after light polymerization and stored for 1 week. For the remaining restorations, finishing was delayed for 1 week. The storage medium was isotonic saline at 37°C throughout the experiment. All restorations were then thermocycled, subjected to dye penetration testing, sectioned and scored. The results suggest that the finishing of composite restorations, bonded with the bonding systems evaluated, should be carried out immediately after light polymerization. Delayed finishing does not improve but instead can be detrimental to the marginal seal of the restorations. The effects of delayed finishing are, however, both bonding system and tissue specific.
Criteria for restoration replacement and restoration life‐span estimates in an educational environment
Authors: Maupomé G. , Sheiham A.
Published: March 2003

The present survey assessed the subjective estimates of restoration longevity, the relative importance of the reasons to replace a restoration and the proportion of restorative treatment perceived to be carried out to replace previous restorations in a clinical setting where caries experience has been reported to be high. Three hundred and eight‐four final‐year dental students in Mexico City (64% female, mean age 23·2 years) made subjective longevity estimates (minimum acceptable, ‘average’ and ideal) for small and large amalgam restorations and cast restorations. Students attributed greater responsibility for restoration failure to patient‐related factors than to dentist‐related factors. The most important reasons given for the replacement of restorations were the presence of an active carious lesion and the presence of a lesion. The next most important reasons were the presence of fractured restorations, proximal overhangs or proximal marginal defects, and marginal defects. No marked differences could be detected in the restoration longevity appraisals compared either with other subjective estimations or to actual longevity figures, nor in the relative ranking of reasons to replace restorations between the estimates done by participants in this study and reports originating in low‐caries settings.
The relationship between satisfaction with mouth and number, position and condition of teeth: studies in Brazilian adults
Authors: Elias A. C. , Sheiham A.
Published: March 2003

The objective of this study was to analyse adults’ subjective perception of satisfaction in relation to number, position and condition of natural teeth. Subjective perception of satisfaction was assessed by interview. Dental status was assessed. Two types of survey were carried out in Brazil: a longitudinal and a cross‐sectional survey. The longitudinal study commenced in 1990, with 227 dentate people aged 45–54 years, of two social classes. Of the 227 subjects examined in 1990, 126 were re‐examined and interviewed 3 years later. The cross‐sectional survey used the same methods used for the longitudinal study. Six hundred and fifty‐seven dentate males aged from 35 to 54 years were examined and interviewed. There was a positive correlation between satisfaction and position of teeth. Premolar pairs had a higher correlation with satisfaction in both studies. Anterior teeth were the most significant predictors of satisfaction. There was no difference in the percentage of satisfied persons between the baseline and follow‐up studies. The results indicate that adults with three premolar pairs and intact anterior sextants were satisfied with their oral status. Keeping a certain number of teeth, depending on their position and condition, gave more satisfaction than having the missing teeth replaced with partial dentures.
In vitro corrosion behaviour and microhardness of high‐copper amalgams with platinum and indium
Authors: LI. B. G. I. , Aydin A. , Isûimer A. , Alpaslan G.
Published: March 2003

Samples prepared from Luxalloy®, GS‐80®, Permite‐C® and Logic® and polished after 24 h by traditional methods were stored in polypropylene tubes containing phosphate‐buffered saline solutions (pH 3·5 and 6·5) and distilled water. The amounts of mercury, silver, tin, copper, zinc, platinum and indium in the test solutions were determined at the first, second, eighth, 52nd and 78th week by atomic absorption spectrometry. At the end of the eighth week the amalgam samples were removed from solutions and evaluated by Rockwell Super Scial Microhardness tester. Statistically significant low amounts of metal ions were measured for Permite‐C® containing indium and Logic® containing platinum. The microhardness test results showed that there were statistically significant increases in the microhardness of Permite‐C® and Logic®. As a result it was shown that the amalgam samples were affected from corrosion conditions to different degrees. Sample of the Logic® group that was stored in distilled water, showed smoother surface properties than other amalgam samples containing high copper. However, it was observed that samples of Permite‐C® group had the smoothest surface properties.
Electromyographic examination of jaw muscles in relation to symptoms and occlusion of patients with temporomandibular joint disorders
Authors: Liu Z. J. , Yamagata K. , Kasahara Y. , Ito G.
Published: March 2003

Clinical/occlusal scores and jaw‐muscle EMGs were recorded in 24 TMD symptomatic (group S) and 20 normal (group N) subjects to evaluate the significance of EMG parameters and their clinical associations. Results indicated: (1) integrated EMG activity (IEMG) was larger at the rest position (RP) in anterior temporalis (Ta) but smaller at maximal voluntary clenching (MVC) in masseter (Ma) and Ta, and the ratios of IEMG at 70%MVC to the corresponding bite force (70%BF) were greater in group S; (2) mean power frequency (MPF) were almost the same in both groups but its shift was more rapid in group S; (3) silent period duration (SPD) was longer in group S; (4) asymmetry indices for SPD and silent period latency (SPL) were larger in group S; (5) muscle pain was associated negatively with IEMG at MVC and 70%BF but positively with IEMGs at RP and 70%MVC, and impaired jaw movements were associated negatively with the above EMG values; (6) muscle pain was positively associated with SPD in Ma, while joint pain and sound showed positive and negative associations with SPD, respectively; (7) associations between occlusion and EMG parameters were found more in group N. These findings verify: (1) jaw elevators in TMD may have hyper‐tonic activities and a weak functional efficiency; (2) jaw muscles in TMD may become easily fatigued following a functional effort, and less relaxed following a muscle twitch; (3) the severity of pain could not be reflected in EMG activities, but impaired jaw movement may increase tonic activity and decrease functional effort; (4) TMD symptoms may alter the functional adaptation of jaw‐muscle activities and occlusion.
Finishing and polishing of the ceromer material Targis. Lab‐side and chair‐side methods
Authors: Behr M. , Rosentritt M. , Leibrock A. , Schneider‐Feyrer S. , Handel G.
Published: March 2003

The aim of the study was to check four lab‐side and four chair‐side methods for finishing and polishing the ceromer material Targis®. Eighty bar‐shaped specimens (20 mm × 10 mm × 2 mm) of Vectris were produced; 72 were covered with a 2 mm (thickness) layer of the Ceromer Targis® and eight samples with the composite Tetric®. All specimens were ground plane parallel with 320 Silicium carbide grit sandpaper in order to start with the same level of roughness. Then the specimens were finished and polished using the following methods: (1) Artglass® toolkit, (2) pumice‐stone and brushes/linen brush and polishing paste P3, (3) Robinson® brush/Ivoclar Universal® paste and wool brush, (4) Silicone wheel and rag wheel, (5) Shofu Rainbow® set, (6) Sof‐Lex® discs, (7) Vivadent Politip® set and (8) Nupro‐pastes® and brushes. The surface roughness was determined with a profilometer. The arithmetical roughness value Ra was calculated. From each group one specimen was randomly chosen and sputtered with gold in order to observe the surface with a scanning electron microscope to evaluate its smoothness. The methods were ranked as followed: 2, 3 and 5 with the lowest roughness, then 8, 6, 7, 4, 1. The best ranked chair‐side method (5) and the best ranked lab‐side methods (2, 3) did not differ significantly between the Ra values. No difference was observed between the composite Tetric® and the ceromer Targis® when these materials were polished using the same method.

Conclusion: the lab‐side‐methods 2 and 3 and the chair‐side‐method 5 can be recommended for finishing and polishing the new ceromer material Targis®.
The effect of bonding agents on the microleakage and bond strength of sealant in primary teeth
Authors: Tulunoğlu Ö. , Bodur H. , Üçtaşli M. , Alaçam A.
Published: March 2003

This in vitro study investigated the effect of use of three dentine bonding agents: Scotchbond Multi‐Purpose Plus® (3M Dental Products, St. Paul, Minnesota, U.S.A.), Syntac® (Vivadent, Schaan, Liechtenstein), Optibond Dual Cure® (Kerr, Romulus, MI, U.S.A.) on microleakage and shear bond strength of a fissure sealant (Helioseal F®, Vivadent, Schaan, Liechtenstein) bonded to either dry or wet (saliva contaminated) enamels of primary teeth. Newly extracted 112 non‐carious primary teeth were sectioned and embedded in resin blocks. Eight groups were formed for each test. Each group consisted of 14 specimens. Group 1 and 2: fissure sealant was applied directly to etched enamel in dry and wet condition, respectively; Group 3 and 4: fissure sealant was applied onto etched and Scotchbond Multi‐Purpose Plus® treated enamel in dry and wet condition, respectively; Group 5 and 6: fissure sealant was applied onto etched and Syntac® treated enamel in dry and wet condition, respectively; Group 7 and 8: fissure sealant was applied onto etched and Optibond Dual Cure® treated enamel in dry and wet condition, respectively. The results revealed that the use of an enamel–dentine bonding agent under fissure sealant increased the bond strength and decreased the microleakage. The use of enamel–dentine bonding agents under sealant in moisture contaminated conditions gave better results than applying sealant alone onto non‐contaminated teeth. Finally, Scotchbond Multi‐Purpose Plus® yielded the best results for both tests.
Caries detector dyes—an in vitro assessment of some new compounds
Authors: Ansari G. , Beeley J. A. , Reid J. S. , Foye R. H.
Published: March 2003

Previous studies have shown that the caries detector dyes, basic fuchsin and acid red, lack specificity. Accordingly, their clinical use can lead to the unnecessary removal of sound tissue. In the present study, the specificity of three further dyes, Carbolan Green, Coomassie Blue and Lissamine Blue was studied. Carious dentine was removed in vitro by means of rotary instruments until the cavities were deemed caries free by conventional clinical criteria. Experimental dyes were applied to the cavity floors, all of which became stained. Stained dentine was removed from half the cavity by means of a burr, the other half remaining as a control. Further stain was then applied and the procedure repeated until no further reduction of the staining of the cavity floor could be achieved. Light microscopy of ground sections of experimental teeth showed that sound tissue had been removed unnecessarily from the experimental half of the cavity due to the lack of specificity of these dyes. This lack of specificity of staining was similar to basic fuchsin and acid red. Only Carbolan Green showed possible differential staining between control and experimental sites, but this was not caries specific. If a clinically useful dye is to be developed, it would need to specifically stain either bacteria in infected dentine and/or the carious degradation products of dentine matrix.
Determination of elastic properties of metal alloys and dental porcelains
Authors: Suansuwan N. , M. V.  , Swain
Published: March 2003

This study aimed to determine Young's modulus, shear modulus and Poisson's ratio of some metal alloys and dental porcelains used in fixed prosthodontics using the technique of impulse excitation of vibration. It also aimed to compare Young's modulus values of these materials with those obtained using the other two methods: the four‐point flexural test and the indentation test using the ultra micro‐indentation system (UMIS). Five types of metal alloys and four types of dental porcelains were tested. The samples were prepared to a rectangular shape of approximately 8×30×1·5 mm. Frequency of vibration in a sample was read when a singular elastic strike was made with an impulse tool. The elastic constants were calculated from the frequency of vibration, dimension and mass of each sample. Young's modulus values resulting from the impulse excitation of vibration are not significantly different (P<0·05) from those obtained using the flexural test and the UMIS test in most metal alloys but are different in titanium, titanium alloy and most of the dental porcelains. The technique of impulse excitation of vibration has proven to be an accurate method and is simple to operate. The elastic properties of these alloys and porcelains are essential for determining the other mechanical properties (fracture toughness) and are relevant in clinical application.
Effect of sandblasting on the bond strength of the bondable molar tube bracket
Authors: Chung K. , Hsu B. , Berry T. , Hsieh T.
Published: March 2003

This study examined the effect of surface treatment with sandblasting on bracket bonding strength. Extracted human tooth, base metal alloy and porcelain surfaces were treated with sandblasting. The bracket bonding strengths of sandblasted surfaces were evaluated and compared with the controls and etched enamel surfaces. Morphological observation of the treatment surfaces and the failure sites was conducted. Statistical analysis included one‐way analysis of variance (ANOVA) and a Scheffe′s F‐test at the 95% confidence level was performed. The results indicated that mean bond strength values ranged from 3·6 MPa (the untreated control) to 20·4 MPa for the etched enamel surface. No statistically significant differences were determined among the etched enamel, sandblasted metal and sandblasted porcelain surfaces (P > 0·05). Most debonding specimens failed at either the resin–tooth interface or within the adhesive. In conclusion, sandblasting the metal and porcelain surfaces obtained a bracket bond strength comparable with that with the etched enamel surface.
Candida albicans colonization on thermal cycled maxillofacial polymeric materials in vitro
Authors: Nikawa H. , Chen J. , Hamada T. , Nishimura M. , Polyzois G.
Published: March 2003

In the present study, the colonization of a single isolate of Canadida albicans on saliva‐, serum‐coated or protein free (uncoated), thermocycled (4–70 °C for 1 min, respectively; 0, 1000 and 10 000 times) 15 commercial maxillofacial materials were investigated, by adenosine triphosphate (ATP) analysis. In the case of control specimens (not thermocycled and uncoated), the fungal colonization appeared to depend upon the type of commercial products used. Thus, the lowest colonization was observed with additional silicone materials, soft acrylic liners with visible light curing, except for one product, whereas visible light curing liners comprising of single paste or single gel exhibited the highest colonization capacity, and cold cured acrylic liners exhibited the intermediate. However, the fungal colonization on the materials was significantly promoted both by thermal cycling (ANOVA; P < 0·01) and a layer of protein coating (saliva, P < 0·01; serum, P < 0·01). When the inter‐relation between the fungal colonization and the surface hydrophobicity of the materials were analysed, fungal colonization on 1000‐ and 10 000‐thermocycled materials correlated well with the contact angles of the materials (Student’s t‐test, P < 0·01), being consistent with the thermodynamic theory. These results, taken together, suggest that the ageing of the materials and the biological fluids of the host promote yeast colonization on maxillofacial materials.
Colour stability of a new light‐cured ceramic stain system subjected to glazing temperature
Authors: Lee S. Y. , Nathanson D. , Giordano R.
Published: March 2003

A light‐cured ceramic stain system (Orbit LC) offers promise as an effective method for surface characterization of ceramic restorations. This study evaluated colour change after glazing procedures for six commonly used stains from this novel system. One hundred and five ceramic specimens were made of the same enamel porcelain powder and standardized in size. The stains were applied on ceramic blocks and light‐cured according to the manufacturer’s recommendations. Porcelain colour was then measured with a calibrated colorimeter before and after each glazing procedure. The CIEL*a*b* colour co‐ordinates were obtained as a measure of the direction and magnitude of colour change. Colour changes were noted for all six stains when subjected to the first glazing procedure (ΔE* = 1·25–4·73). Brown, orange and green stains showed the greatest colour shifts (ΔE* > 3·3), which might be considered clinically significant. However, the colour change is not of the same pattern in the colour space. Compared with the first glazing procedure, the second and third glazing procedures demonstrated less effect on the colour stability of the stains (ΔE* = 0·36–1·12). The results provide important information about colour shifts in the system, which require overcorrection during stain application.
Defects of dental appearance assessed by patient and dental student groups
Authors: Ashley M. , Lamb D. J. , Ellis B.
Published: March 2003

A study was carried out to establish the relative need for treatment of a range of defects of dental appearance and identify differences between individual and group assessments. Three groups (n = 42), two of patients (one referred for a defect of dental appearance and one not) and one of dental students, assessed urgency of need on a visual analogue scale (VAS), of four cases of dental defect presented as colour prints. All groups rated the need for treatment of the four cases in the same order. Data sets were non‐normal with wide ranges. Patients without a defect of appearance usually assessed treatment need as significantly less urgent. Marked variation was discovered between individual assessments within otherwise similar groups. Based on group decisions, guidelines for treatment of defects of dental appearance could be established. However, so extreme are individual variations that very sympathetic application would be needed if dissatisfaction is not to result.
Influence of restorative manipulations on the blood perfusion of human marginal gingiva as measured by laser Doppler flowmetry
Authors: Vág J. , Fazekas Á.
Published: March 2003

Plaque accumulation caused by deficient fixed prosthodontics may evoke unequal degrees of gingival inflammation. Clinical investigation was performed to study the reaction of marginal gingiva during the course of routine prosthetic rehabilitation, e.g. replacement of two two‐unit fixed partial dentures for aesthetic and functional reasons in a female patient. To characterize the actual state of gingival margin we recorded conventional gingivitis indices in conjunction with the employment of non‐invasive laser Doppler flowmetry (LDF) for gingival perfusion measurements. Prior to the treatment procedures (control phase) the gingival indices were scored to 1 at all the five measuring points. At the end of the rehabilitation those values decreased to zero. A significant correlation was found between gingival indices and LDF readings (r=0·37, n=49, P < 0·01). Thus, our data suggest that monitoring of gingival blood perfusion by LDF may provide valuable information on the healing process of inflamed marginal gingiva.
Vibration analysis of maxillary removable partial denture frameworks
Authors: Inoue T. , Oki M. , Phankosol P. , Ohyama T. , Taniguchi H.
Published: March 2003

The purpose of this study was to investigate the vibratory characteristics of three designs of the Class I Kennedy maxillary removable partial denture frameworks as the basic study. Their major connectors comprised a U‐shaped palatal connector (UPC), single palatal bar (SPB), and anterior–posterior palatal bars (APB). Frequency response functions were measured when the framework was impacted. The modal shape was observed and the decay rate was calculated using modal analysis software. The results showed that the vibratory properties of each framework differed from each other. Within the range of frequencies from 10 to 2000 Hz, the UPC type had seven natural frequencies, while the SPB and the APB types had six. The UPC type had a greater number of natural modes accompanied by elastic deformation, including fluttering and twisting, than the other type, and the UPC type was considered to be unfavourable. The decay rate of the APB type was significantly higher than those of the UPC and the SPB types (P < 0·01).
Histopathological changes in the tissues under a denture base in experimental osteoporosis with a non‐pressure covering or bearing continuous pressure
Authors: Oki K. , Sato T. , Hara T. , Minagi S.
Published: March 2003

In this study, the experimental denture base on the hard palate of the molar region of osteoporotic rats was designed to cover without any mechanical pressure or to load continuous pressure (0·5, 1·5 or 3·4 kPa). Experimental osteoporosis was induced by ovariectomy and feeding on a low calcium diet. Histopathological changes induced by non‐pressure covering or continuous pressure in the tissues under the experimental denture bases were examined. Regarding the histological changes induced by continuous pressure, this was evaluated in relation to the time course of the intensity of the continuous pressure. In the tissues under the denture base in osteoporotic condition with non‐pressure covering, no histopathological changes caused by non‐pressure covering were observed except for a transient slight proliferative reaction in the epithelial ridge. The following histopathological changes were observed in the tissues under the denture base in the osteoporotic condition bearing continuous pressure; (i) bone resorption was induced on the periosteal surface (Ps) in the osteoporotic‐3·4 kPa group, and on the pressure side of the endocortical surface (p‐Ec) in the osteoporotic‐1·5 and ‐3·4 kPa group, (ii) the appearance of osteoclasts on the p‐Ec in the osteoporotic‐3·4 kPa group was earlier than that on the Ps in a same group, (iii) bone resorption on the pressure side of the Ec in the osteoporotic‐3·4 kPa group manifested at the earlier stage than that in the osteoporotic‐1·5 kPa group, (iv) bone formation following bone resorption on the p‐Ec was observed more markedly than that on the Ps and (v) histopathological changes in the tissues under the denture base in experimental osteoporosis bearing continuous pressure had an intimate relationship with the initial intensity and the time course of continuous pressure.
Bond strength of five current adhesives to caries‐affected dentin
Authors: Sengün A. , Ünlü N. , Özer F. , ÖztÜrk B.
Published: March 2003

Summary Five current dentin adhesives were evaluated for their ability to bond to caries‐affected dentin. The materials were: total etch [Solid Bond (SB)], two self‐etch [Clearfil SE Bond (CSE), Etch and Prime (EP)], two one bottle [Prime and Bond 2·1 (PB), One Coat Bond (OCB)]. Sixty extracted molar teeth with proximal caries (mesial or distal) extending into mid‐dentin were used. By grinding normal and caries‐affected proximal surfaces, flat dentin surfaces were obtained. The surfaces were then bonded with each adhesive system and composite resins were added to the surfaces by packing the material into a cylindrical‐shaped plastic matrix with an internal diameter of 2·5 mm and height of 3 mm. Shear bond testing was performed following 10 days incubation of specimens in distilled water at 37 °C. Results were analysed by Kruskal–Wallis ANOVA, and Mann–Whitney U multiple comparison test and Wilcoxon rank tests. The results obtained with CSE, SB, and EP were similar in caries affected and normal dentin (P > 0·05). But bonds made to normal dentin with OCB and PB were lower (P < 0·05) than bonds to caries‐affected dentin. Bonding to caries‐affected dentin with CSE (24·49 ± 5·38), SB (21·49 ± 9·15), and EP (21·19 ± 9·17) showed shear bond strengths higher than OCB (17·43 ± 9·78) and PB (14·10 ± 7·94) (P < 0·05). Bonding to normal dentin with CSE (29·91 ± 8·95) was the highest (P < 0·05). SB (21·17 ± 5·41) and EP (17·45 ± 6·21) showed shear bond strengths higher than OCB (11·99 ± 10·15) and PB (10·57 ± 4·56) (P < 0·05).
Dynamic viscoelastic properties of commercial glass‐fibre reinforced resin used for crowns and bridges
Authors: FUJII K. , ARIKAWA H. , KANIE T. , HAMANO T. , NISHI Y. , NAGAOKA E.
Published: March 2003

Summary In order to investigate the thermal stability, the physical and mechanical, and dynamic viscoelastic properties of glass‐fibre reinforced composite materials were measured. The G′ of the seven materials examined was within 5˙20 ± 14˙55 and 4˙50–14˙35 GPa for dry and wet specimens in air at 37 °C, respectively, and decreased with increasing temperature. The G′ values of dry specimens decreased by 7˙74–15˙4% when heated to 60 °C. The value of tan δ ranged from 0˙0102 to 0˙0295 and from 0·0181 to 0·0406 for dry and wet specimens in air at 37 °C, respectively. The coefficient of linear thermal expansion between 30 and 60 °C ranged from 0˙557 to 3˙95 × 10–5/°C. Moreover, the filler content ranged from 56˙36 to 88˙87 wt%. These results showed that the magnitudes of G′, tan δ, and the coefficient of linear thermal expansion and water absorption depend on the inorganic filler or glass‐fibre content; i.e. the amount of resin matrix. Moreover, for all the materials examined, the G′ values were thermostable in the temperature range encountered in the oral cavity.