bluuebunny/crossref_metadata_2025_split huggingface dataset:
Studies related to reaction of supporting soft tissue to denture wear: the histological response of vervet monkey oral epithelium to a ‐80 mmHg vacuum
Authors: GROSSMAN E. S. , FORBES M. E. 
Published: June 2007

SummaryThe histological response of vervet monkey oral epithelium to a negative force similar to that experienced under dentures was investigated. Using impression trays with adherent impressions linked to a vacuum pump, the epithelia of the hard palate, attached gingiva and alveolar mucosa of 16 monkeys were subjected to a continuous vacuum of ‐80 mmHg, and then fixed by perfusion and immersion while in situ. After processing for light microscopy, sections were measured to obtain the rete peg length, supra‐papillary width, epithelial width and basal, spinous and superficial cell density 700 μm−2. Mean values and standard deviations were calculated for each measurement and, using Student's t‐test, these data were compared with results obtained for normal tissue from nine additional monkeys. The vacuum caused an increase in epithelial width in the palate and attached gingiva, and a decrease in epithelial width in the alveolar mucosa. The cell density 700 μm−2 decreased significantly in all layers of the palate, but increased in the basal layer of the attached gingiva and the basal and superficial layers of the alveolar mucosa. The alveolar mucosa within 0.5 mm of the mucogingival junction showed a variable response. This study demonstrates that a vacuum of ‐80 mmHg modifies the structure of the oral epithelium, and this response is directly related to the functional demands of the tissue.
Comparison of food particle distribution masticated by subjects wearing complete dentures and with natural teeth
Authors: CHONG‐SHAN SHI , GUAN OUYANG , TIAN‐WEN GUO 
Published: June 2007

SummaryThe sizes of soya particles masticated by 12 complete denture wearers and 10 subjects with natural dentition were directly measured by means of a graphic digitizer and computer, following a varied number of chewing strokes. It was found that the chewed particle size frequency distributions of the two groups tended to a state of normal logarithm distribution. Compared with the dentate subjects, the mean, 20th, 50th and 80th percentile of the particle sizes chewed by complete denture wearers were increased, whilst the distribution shapes were nearly identical. The results suggest that there are no qualitative differences in the manner in which the two groups break up food. Selection and breakage functions of complete denture wearers are decreased, and this could be related to the denture conditions and the change of oral state in such individuals.
Observations on the motor control of brief teeth clenching in man
Authors: CHRISTENSEN L.V. , CARR A.B. , DONEGAN S.J. , ZIEBERT G.J. 
Published: June 2007

SummaryWithout artificial feedback control, maximum voluntary isometric contractions were performed for about 1 s by six subjects. Randomly selected surface electromyograms of the anterior temporalis and masseter muscles suggested that, in some cases, the motor control of the entire isometric contraction might have been preprogrammed through the phenomenon of anticipation. In the majority of cases, the control of the initial contraction phase might have been preprogrammed, followed by a phase of servo‐controlled motor activity. As a functional basis for the servo‐control of isometric force generation, it was suggested that compartmentalized ‘extrafusal and intrafusal motor units’ were recruited and decruited in an orderly manner, and periods of alphamotor inhibition were interpreted as signs of switching from one control scheme to another, possibly via a transcortical loop.
Force‐related changes in the masseter muscle reflex response to tooth‐taps in man
Authors: BJØRNLAND T. , BRODIN P. , AARS H. 
Published: June 2007

SummaryIn 14 subjects with no disorder of the masticatory apparatus, excitatory and inhibitory reflex responses in the masseter muscles were derived by standardized mechanical stimulation of the upper central incisor. A series of eight taps was delivered during isometric contraction at 40% of maximum EMG activity, with tapping forces ranging from 0.25–9 N. The mean post‐stimulus masseteric EMG complex (PSEC) consisted of up to three inhibitory (I‐1, I‐2 and I‐3) and three excitatory phases. The first inhibitory wave increased in duration with increasing tapping force, and the second and third inhibitory waves occurred at higher thresholds than the first inhibitory wave.
Masseteric post‐stimulus EMG complex following mechanical stimulation of osseointegrated oral implants
Authors: BONTE B. , van STEENBERGHE D. 
Published: June 2007

SummaryPeriodontal receptors can be located in the periodontal ligament itself, the alveolar bone, the periosteum and the gingiva. The aim of the present study was to quantify the contribution of the periodontal ligament receptors in eliciting a reflex response in human masseter muscles. Surface EMG recrordings were made in 17 human subjects, fully or partially edentulous, and all provided with osseointegrated oral implants ad modum Brånemark. They maintained a constant clenching level. Mechanical stimulation of an oral implant in the upper central incisor region failed to elicit a reflex in fully edentulous subjects with oral implants in both jaws. The absence of a reflex response strongly suggests that the receptors in the periodontal ligament itself are mainly responsible for the reflex. Stimulation of the same area in subjects with oral implants in the upper jaw and natural teeth in the lower jaw clicited a reflex response in most subjects. Since they were instructed to clench in full habitual occlusion, transmission from the stimulated area to periodontal receptors of natural teeth is very probable.
Influnece of an occlusal splint on integrated electromyography of the masseter muscles
Authors: SHAN SHI CHONG , YUN WANG HUI 
Published: June 2007

SummaryIn order to examine the effect of an occlusal splint on the integrated electromyography (EMG) of the masticatory muscles, EMG of bilateral masseter muscles of 23 patients with temporomandibular joint distrubance syndrome (TMJDS), with and without an occlusal spint, was measured and integrated on line during maximum clenching. It was found that the integrated myoelectrical value of the masseter muscle on the involved and non‐involved side was reduced with the occlusal splint. The absolute difference between integrated myoelectrical values in the left and right masseter muscles was reduced with an occlusal spint, but the relative difference remained virtually unchanged. These results indicate that the occlusal splint can decrease masseter muscle activity and thus exert a therapeutic effect.
Causes and signs of temporomandibular joint pain and dysfunction: an electromyographical investigation
Authors: SCHROEDER H. , SIEGMUND H. , SANTIBÁÑEZ‐H G. , KLUGE A. 
Published: June 2007

SummaryThe spontaneous muscular activity of the masseter and two non‐masticatory muscles, and their activity under conditions of noise and flickering light, were recorded in 30 patients with mandibular dysfunction, and in 25 control subjects. The mood of the subjects during the investigation, and the possible presence of emotional disturbances was evaluated by means of questionnaires. The enhanced muscular activity of the masseter muscle differentiated patients from the control group, although it does not constitute a pathognomic sign. Unilaterality of complaints, and dysfunctions of differing intensity were not reflected in differential EMG findings. One‐fifty of the patients exhibited neck muscle activity occurring simultaneously with the masseter activity. The effect of the applied stimuli on the muscular activity was not homogeneous, leading to activation in some cases and inhibition in others. Symptoms of anxiety could be observed in seven TMJ patients. Anxious patients showed higher levels of muscular activity and emotional irritability during the experiment than non‐anxious patients.
Reproducibility of electromyographic measures: a statistical analysis
Authors: FERRARIO V.F. , SFORZA C. , D'ADDONA A. , MIANI A. 
Published: June 2007

SummaryThe masseter, temporalis anterior and digastric anterior muscles of five volunteers have been investigated by means of surface electromyography. Each muscle was tested by three operators at different times and under three distinct conditions of intermaxillary relationship: resting, with no occlusal contact (physiological rest position); occlusion in centric occlusion (C.O.) without clenching force; and maximum voluntary clench. In all the trials the BIO‐PAK system (Bio‐Research Associates Inc., Milwaukee, WI, USA) was used. Measurements were made in two consecutive experimental trials separated by an interval of about 15 days. In the first trial the operators had minimal instrumental experience. while in the second trial the same operators had performed at least 30 measurements each. The data have been analysed by a factorial variance analysis, particularly with a view to comparing the variability between operators for each volunteer subject. The analysis revealed statistically significant differences only in the first experimental trial, due to the operators' lack of experience. The study demonstrates that the electromyographic system and protocol used allow good reproducibility of measurements. Furthermore, they have potential applications in both clinics and research.
Defects in automixed addition silicone elastomers prepared by putty‐wash impression technique
Authors: SOH G. , CHONG Y.H. 
Published: June 2007

SummaryVoids presenting in impressions of five automixed addition silicone elastomers were investigated. Impressions were prepared with the putty‐light body impression technique on stainless‐steel cylinders with acrylic spacers. The number of voids was counted at a predetermined site on three separate days using a stereomicroscope at x7 magnification. Impression specimens of a hand‐mixed addition silicone, and from hand‐mixing of the automixed materials, were made for comparison. Express gave a significantly higher number of voids than other automixed materials, with President Jet having the lowest void count. Automixed materials generally produced impressions with significantly fewer voids than the hand‐mixed material. Automixing was effective in reducing void defects in elastomeric impressions.
Age and maintenance of removable dentures in Finland
Authors: MURTOMAA H. , KÖNÖNEN M. , LAINE P. 
Published: June 2007

SummaryThe age and maintenance of dentures, and denture‐cleaning habits, were studied by an interview survey. The material represented nation‐wide the Finnish population aged ≥ 15 years old, and there were 957 interviewees, of whom 328 were denture wearers. In total, 45% of the upper and 40% of the lower dentures were over 10 years old. More than one‐third of the dentures more than 5 years old had never been maintained during that time. Individuals whose dentures had been made and fitted by dental technicians visited dentists less frequently than individuals whose dentures had been made by dentists. Over 80% of the denture wearers reported cleaning their dentures by brushing at least once a day, and women cleaned them more frequently than men. The present findings suggest that denture wearers should be a special target group for dental health education, for the development of the latter, and for the development of dental health care services in the future.
Surface electromyographic estimates of recruitment/rate coding of masseteric motor units
Authors: DONEGAN S.J. , CHRISTENSEN L.V. , KALTENBRUNNER A. M. G. 
Published: June 2007

SummarySurface electromyographic (EMG) recordings were obtained from the masseter muscles in healthy subjects performing brisk maximum voluntary teeth clenching (MVC) for about 1s. During the onset (0–600 ms) of ballistic MVC activity, the peak amplitude of the EMG interference patterns showed a consistent and significant increase, on examination for 0–200 ms, 200–400 ms, and 400–600 ms of MVC activity. The peak (maximum) and median (centroid) frequencies of power spectrum density functions of the raw surface EMGs (interference patterns) showed an absence of consistent and significant changes during 0–600 ms of ballistic MVC activity. However, the estimated total energy contents (peak amplitude × peak frequency) of the surface interference patterns showed a consistent and significant increase from 0 to 600 ms of ballistic MVC activity, and this was interpreted as global recruitment/rate coding of masseteric motor units.
Number and intensity of occlusal contacts following surgical correction of mandibular prognathism
Authors: ATHANASIOU A.E. 
Published: June 2007

SummaryThe aim of the present investigation was to study the changes in the number and intensity of occlusal tooth contacts in the intercuspal position following surgical correction of mandibular prognathism. The study sample consisted of 33 adults with mandibular prognathism whose management included bilateral vertical ramus set‐back osteotomy and combined orthodontic treatment. Measurement of the number and intensity of occlusal tooth contacts was performed by means of the photocclusion technique. Recordings of the number and intensity of occlusal contacts were made 1 day before operation and 6 months post‐surgery. Testing of the differences of the means for both the number of occlusal contacts and their intensity between the two phases was achieved by means of a paired t‐test. The results of the study showed that the combined orthodontic and surgical treatment produced a significant increase (P < 0.001) in the number and intensity of occlusal contacts (4.54 and 160 kg mm−2 respectively). However, whether this increase in occlusal contacts resulted in an overall improvement in craniomandibular functional status cannot be answered by the present study.
Reinforcement of acrylic resin denture base material with metal or fibre strengtheners
Authors: VALLITTU P. K. , LASSILA V. P. 
Published: June 2007

SummaryThe effect of different metal and fibre strengtheners on the fracture resistance of polymethylmethacrylate was tested. Different types of commonly used metal wire and glass fibre, as well as carbon and aramid fibres, were used as strengtheners in test specimens. There were 21 groups, and each group contained 12 test specimens. Each metal strengthener had a beneficial effect on the fracture resistance of the polymethylmethacrylate (P<0.001–0.01). Some fibres, which were silanized for better adhesion, also had strengthening properties.
The clinical performance of a posterior composite resin restorative material, Heliomolar R.O.®: 3‐year report
Authors: KNIBBS P.J. , SMART E.R. 
Published: June 2007

SummaryA posterior composite resin restorative material was evaluated over a 3‐year period by means of a controlled clinical trial. A total of 52 composite resin restorations and 52 amalgam alloy restorations were included in this trial, and were examined with regard to marginal integrity, surface texture, anatomical form and proximal contact with adjacent teeth. There were no significant differences in clinical performance between test and control materials, which both gave good service over the period of evaluation. Only five restorations (one of amalgam and four of composite resin) failed during the trial. Plastic replica dies were used to support the clinical examinations of the restorations, and such dies were found to be helpful.
Digital imaging techniques for dental alloy castability quantification
Authors: COHEN S.M. , VAIDYANATHAN T.K. , TANABE N. 
Published: June 2007

SummaryIn this study, mesh monitors cast from experimental compositions of a Ni‐Cr‐Be alloy are evaluated by the application of image analysis techniques. Castability values obtained by this method are then contrasted with those from three commonly employed manual counting procedures. While castability values obtained by all methods reflect the effect of compositional variations, a comparison of results with respect to evaluation method indicates that the image analysis technique consistently yields higher castability values, especially evident in the poorly casting groups. The apparent explanation for these observed differences is that with imaging, segments that are partially cast to varying degrees are not arbitrarily eliminated from the data, as is the usual practice in manual counting methods; therefore, castability values obtained by using the imaging technique will very closely reflect an actual alloy volume of each cast monitor.
Microleakage of indirect inlays placed on different kinds of glass ionomer cement linings
Authors: KARAAǦACLIOǦLU L. , ZAIMOǦLU A. , AKÖREN A.C. 
Published: June 2007

SummaryThe objective of this study is to compare the marginal seal of Class II cavities restored with indirect inlays constructed on glass ionomer cement linings having different curing properties. Also the effect of acid‐etching of these liners on microleakage was investigated.Mesio‐occlusal and disto‐occlusal cavities in 80 extracted human molars having the cervical floor below the cementoenamel junction were prepared (n:160). Half of the preparations were restored with Ceramco II® porcelain and the rest with SR‐Isosit® resin inlay material. Liners as light curing lonoseal® light+chemically curing LCL 8® and Zionomer® and chemically curing Ketac‐Bond® glass ionomer cements (GICs) were used. On mesial preparations GICs were acid‐etched but were not on distal preparations. All inlays were cemented with Ultrabond® composite material. After thermocycling the teeth were placed in a basic fuchsin dye solution for 24h, then each tooth was sectioned. By using a stereomicroscope the extent of marginal leakage was scored and statistically evaluated.Microleakage was observed beneath all GIC linings and was more extensive between light curing GIC/dentine interface. By acid‐etching of GICs the microleakage between GIC/dentine interface was increased significantly. Whether acid‐etching was applied or not a significantly increased microleakage was recorded between chemically curing GIC/composite interfaces. Although the marginal microleakage was witnessed in both inlays, it appeared that porcelain inlays provided a better marginal seal, in comparison to SR‐Isosit inlays.
Physics and the sounds produced by the temporomandibular joints. Part I
Authors: CHRISTENSEN L. V. 
Published: June 2007

SummaryIn clinical dentistry, the sounds (clicking) and noises (grating) produced by the temporomandibular joints (TMJ) usually signify dysfunction or disease of the mandibular locomotor system. In an attempt to provide guidance to the general practitioner, this article discusses some pertinent parameters defining the physics of airborne and solidborne vibrations.
Physics and the sounds produced by the temporomandibular joints. Part II
Authors: CHRISTENSEN L.V. 
Published: June 2007

SummaryIn clinical dentistry, the solidborne vibrations (tissue pressure waves) produced by the temporomandibular joints (TMJ) may signify dysfunction or disease of the mandibular locomotor system. This article discusses aspects of the applied mathematics and electronic recording of solidborne vibrations of the TMJ (electrovibratography).
Contribution of the mucosal tactile information to the mandibular position sense in paticnts wearing dentures
Authors: Munakata Y. , Kasai S. 
Published: June 2007

SummaryThe effects of mechanicals stimulation of denture‐bearing mueosa on the perception of mandibular position was tested in five patients wearing dentures. In order to produce mucosal stimulation of different intensities, five types of a punctate stimulus plate each having a different number of raised points was used. A hydraulic vertical displacement meter was also used so as to vary mandibular position. The mandibular position sense altered with changes in the physical stimulus intensity to the denturebearing mucosa within a limit of jaw separation (less than 2.3 mm). In addition, the increases of the stimulus intensities stabilized the response regarding the mandibular position discrimination. From these results, it has been suggested that the tactile information from the denture‐bearing mucosa regulates the neural mechanism concerning the mandibulr position discrimination.
Influence of lower lip support on recording of vertical dimension in edentulous patients
Authors: EKFELDT A. , KARLSSON S. 
Published: June 2007

SummaryThe purpose of this investigation was to assess the influence of differences in design of the occlusion rim on recorded vertical dimension in complete denture therapy. Edentulous patients were studied with an opto‐electronic method when the vertical dimension of rest was established with and without labial support of the occlusion rim. As no significant differences were found, the results did not support the hypothesis that the contour of the lip support will influence the recorded physiological rest position. However, a significant difference between intra and extraoral placement of the point of measurement was found.
The effect of time of trimming on the surface finish of anterior composite resins
Authors: HEATH J.R. , JORDAN J.H. , WATTS D.C. 
Published: June 2007

SummaryThis in vitro study investigates whether the surface smoothness of a finished composite resin is a function of the time at which it is trimmed. Five materials were studied. Visiodispers® (VIS) is a sintered microfine, the remainder were hybrid formulations: Miradapt® (MIR), Command Ultrafine® (COM) and two experimental formulations –‘EXP (2)’and‘EXP (15)’– with larger filler particles. All except MIR were photoactivated. Samples were placed and cured in holes machined in Perspex rods, ensuring excess of material and moulded to shape with cellulose acetate matrix strip. The strips were removed immediately after light curing and after 5 min in the case of MIR. Sample groups were finished after the following intervals: 10, 15, 30, 45 s, 1, 2, 3, 4, 5min, dry, and after 1 and 7 days in 37°C water. The finishing procedure used plain‐cut tungsten‐carbide burs and coarse, medium and fine finishing discs, which were applied for standardized times, directions and pressures. Surface roughness was assessed visually and with a surface profilling instrument. COM and VIS materials significantly improved in surface finish when the procedure was delayed for 7 days. However, EXP (2), EXP (15) and MIR surface finishes were independent of finishing time. This may result from a rapid attainment of optimum surface hardness, whereas with COM and VIS incomplete curing leads to smearing of resins and filler across the surface.
Effect of dental metals on magnetic resonance imaging (MRI)
Authors: MASUMI S. , ARITA M. , MORIKAWA M. , TOYODA S. 
Published: June 2007

SummaryThe aim of this research was to examine the effects of metals used in dentistry upon magnetic resonance imaging (MRI). Ten disk‐shaped samples of metals have been used in this study. Each sample has been set into a volunteer who had produced a normal MR image when tested. The subject was imaged in the sagittal, frontal and coronal plane with a 0.1T MRI device and results examined for MR defects.Au, Ag, Au‐Ag‐Pd and amalgam produced no defect. Ni‐Cr, Co‐Cr and SUS304 expressed small amounts of MR defects, but SUS405, Pd‐Co‐Ni and Sm‐Co expressed large defects. Those metals which create MR image degradation must not be used for fixed prosthesis or orthodontic devices both of which could easily be made from other metals. If the MR image degrading metals are to be used in dentistry, their application should be restricted to removable prosthesis.