bluuebunny/crossref_metadata_2025_split huggingface dataset:
The production of secondary caries‐like lesions on cavity walls and the assessment of microleakage using an in vitro microbial caries system
Authors: GILMOUR A. S. M. , EDMUNDS D. H. , DUMMER P. M. H. 
Published: June 2007

SummaryThe aim of this study was to assess microleakage along restored cavity walls using a new in vitro microbial technique. Extracted human teeth containing cavities restored with a microfine posterior composite were incubated in broth inoculated with a single strain of Streptococcus mutans for 10 days, using a sequential batch culture technique. Each margin of the cavities was finished in one of three ways: butt joint and etching; butt joint and no etching, or; bevel joint and etching. The assessment of microleakage was achieved by examining sections of the teeth histologically using polarized light for the presence or absence of caries‐like cavity wall lesions. Outer (surface) lesions were also examined and displayed the characteristic zones of early natural caries lesions. The cavity wall lesions were observed as a translucent zone in 31% of butt and unetched margins, 16% of butt and etched margins, and 5% of bevelled and etched margins.
Microleakage in alloy‐glass ionomer lined amalgam restorations after thermocycling
Authors: ARCORIA C.J. , FISHER M.A. , WAGNER M.J. 
Published: June 2007

SummaryMarginal microleakage was measured around amalgam restorations lined with alloyglass ionomer cement and coated with a glass ionomer varnish. Preparations were made in 48 human extracted mandibular molar teeth. Alloy‐glass ionomer liners and varnishes were placed into selected preparations. Tytin amalgam was inserted into all of the teeth and left unburnished and unpolished. Half of the total samples were thermocycled for 5 days and the remainder were left in deionized water. The teeth were immersed in a 0.5% methylene blue dye and sectioned vertically with a diamond saw. Microleakage was scored visually at xl00 magnification, and the data were analysed using the Mann‐Whitney U‐test (P≤0.05). Thermocycling did not have a significant effect on microleakage, except when both an alloy‐glass ionomer liner and varnish were used. Overall, the use of an alloy‐glass ionomer liner made the most significant difference in reducing microleakage.
The effect of etching on glass polyalkenoate cements
Authors: AGGART S. E. T , PEARSON G. J. 
Published: June 2007

SummaryThe effect of acid etching on the surface appearance and flexural strength of four glass polyalkenoate cements was investigated. Specimens were etched for intervals of 10–60 s, both at the recommended time after mixing and after a 24‐h delay. The surface texture was examined microscopically. Further specimens were subjected to a 4‐point bend test following etching 1 h and 24 h after mixing. Deterioration of the surface appearance occurred as the etching time was increased beyond 10 s following immediate etching. Etching after 24 h reduced surface damage, but a 10‐s etch still gave the most favourable surface appearance without loss of particulate material.Etching beyond 10 s significantly reduces flexural strength.
A comparison of two methods for locating the intercuspal position (ICP) whilst mounting casts on an articulator
Authors: WALLS A.W.G. , WASSELL R.W. , STEELE J.G. 
Published: June 2007

SummaryThe accuracy of two different techniques for locating casts in the intercuspal position (ICP) in a semi‐adjustable articulator was assessed. The techniques for establishing the ICP were a polyether interdental registration, or location of the casts in a position of maximum interdigitation using tactile and visual methods.Fifty‐three sets of study models were used in this investigation. Each set of study models was mounted on two occasions, once with each of the two techniques. The models were divided into two groups at random, and mounting and assessment procedures were performed using a single blind crossover design. The quality of the contacts between the mounted casts was compared with the results of an occlusal examination of the same subjects.Hand articulation of the casts prior to mounting the lower cast against the upper cast was a more accurate means of locating the ICP than the use of a low‐viscosity polyether interdental registration material, unless there were difficulties in establishing the ICP by visual and tactile methods.
Occlusal contacts in maximum intercuspation and craniomandibular dysfunction in 16‐ to 17‐year‐old adolescents
Authors: GIANNIRI A.I. , MELSEN B. , NIELSEN L. , ATHANASIOU A.E. 
Published: June 2007

SummaryThe relationship between number, distribution and intensity of occlusal tooth contacts and the craniomandibular functional status was investigated in 56 subjects aged 16–17 years. The photocclusion technique was used for the qualitative and quantitative evaluation of occlusal contacts, and a clinical examination was performed to assess the function of the stomatognathic system. According to a matched‐pairs design two groups were formed, one consisting of individuals with signs of craniomandibular disorders, and the other consisting of functionally healthy adolescents. The pairs were matched according to morphological occlusal characteristics.The results of the present study emphasize the importance of occlusal contacts in relation to craniomandibular function. In particular the posterior occlusion appeared to be related to function, since statistically significant differences between the two groups were detected with regard to the number and load of contacts. Symmetry of intensity rather than symmetry of contact distribution per se seemed to be important in relation to craniomandibular function.
Mandibular reaction time to auditory and visual signals in young and elderly subjects
Authors: NAGASAWA T. , YUASA Y. , TAMURA H. , TSURU H. 
Published: June 2007

SummaryMandibular reaction time was measured in young and elderly volunteers. Each subject was instructed to open the jaw from the closed position and to close the jaw from the open position as quickly as possible after perceiving an auditory or visual signal. The reaction time of the elderly subjects to both signals was significantly slower than that of the young subjects. This was due almost entirely to prolongation of the premotor time component. There was no difference in the maximum velocity of the jaw movement between the two groups of subjects.
Reflected light microscopy of the human mandibular condyle – a study of a post‐mortem material
Authors: JAGGER R. G. 
Published: June 2007

SummaryThe surface characteristics of the articulating surfaces of 11 human mandibular condyles removed post‐mortem were determined by the use of reflected light dark‐field microscopy. Good agreement was obtained between macroscopical grading of degenerative change and appearance as observed by microscopy. Microscopical appearances believed to correspond to normal surface, fibrillation and degenerative changes are described.
Stimulus‐response latencies of two instruments delivering transcutaneous electrical neuromuscular stimulation (TENS)
Authors: GOMEZ C. E. , CHRISTENSEN L. V. 
Published: June 2007

SummaryStimulus‐response latencies of low‐frequency transcutaneous electrical neuromuscular stimulation (TENS) were studied in 15 healthy subjects, applying the two different pulse configurations delivered by the Biotens and the Myomonitor instruments. Latencies, in milliseconds, were determined on bipolar raw surface electromyograms (EMG) of the suprahyoid muscles, using the skin surface over the sigmoid notches of the mandible as the site of stimulation. Stimulus‐response times were measured from the onset of the stimulus artefact to the first response peak on EMG, and their mean values showed ranges of 3.79–4.49 ms for Biotens and 5.10–5.34 ms for Myomonitor. It was concluded that low‐frequency TENS caused direct stimulation of motor nerves, and that the timing of the contraction response was not affected by altered electrode placement, lead‐wire reversal or unbalanced (right/left) stimulation.
An electrognathographic study of aspects of ‘deprogramming’ of human jaw muscles
Authors: CARR A.B. , DONEGAN S.J. , CHRISTENSEN L.V. , ZIEBERT G.J. 
Published: June 2007

SummaryThree‐dimensional electrognathography of an incisor point was used to detect peripheral correlates of deprogramming of the jaw elevator muscles. Putative deprogramming was attempted through the clinically recommended use of a leaf gauge, placed for 10–15 min between the maxillary and mandibular anterior teeth and disoccluding the posterior teeth by about 2 mm. Studied mandibular displacements were those that occurred during voluntary elevation of the mandible from the postural to the intercuspal position. Use of the leaf gauge did not affect the displacement patterns. Within a freeway space of about 0.2 mm3, the incisor point moved about 2 mm vertically, about 1 mm sagittally, and about 0.2 mm laterally.
Thermal effect on the dissolution of mercury from two dental amalgams
Authors: SOH G. , CHEW C. L. , LEE A. S. , YEOH T. S. 
Published: June 2007

SummaryVarious factors affect dissolution of mercury from dental amalgams. In this study we examined the effect of temperature on the release of mercury from two dental amalgams, namely an admixed high‐copper amalgam (Contour) and a new tin‐ and copper‐free amalgam (Composil). Ten cylindrically‐shaped specimens of each type of amalgam were used in this investigation, and were divided into two equal groups. The five specimens in each group were each incubated in 10 ml purified water at either 37°C or 60°C, with a change of water every 24 h over an 8‐day period. The quantity of mercury released from each amalgam specimen during each incubation period was expressed as μg cm−2 24 h−1. The amount of mercury released was estimated by cold‐vapour atomic spectrometry. The results demonstrate that specimens incubated at 60°C released significantly larger amounts of mercury than specimens incubated at 37°C for both types of amalgam. The release of mercury by Composil was significantly greater than that by Contour (P≤0.0001) for both temperatures studied. Raising the incubation temperature caused a disproportionate increase in mercury release from Composil compared to Contour.
Shortened dental arches and periodontal support*
Authors: WITTER D.J. , DE HAAN A.F.J. , KÄYSER A.F. , VAN ROSSUM G.M.J.M. 
Published: June 2007

SummaryThe periodontal support of subjects with shortened dental arches (SDA, n=74), and of subjects with SDA and free‐end removable partial dentures in the lower jaw (SDA and RPD, n=25) was compared with that of subjects with complete dental arches (CDA, n=72). The periodontal support was determined by tooth mobility and alveolar bone height, measured on a radiograph, of the distal alveolar bone of the premolars. Significant differences in tooth mobility were found between the three groups of subjects. The relative bone height showed a trend towards lower values for the SDA group and the SDA and RPD group. For some teeth these differences were significant. Premolars that are the most posteriorly located occluding teeth in the dental arch tend to have a lower relative alveolar bone height than premolars in an intermediate location. This effect is more marked in the upper jaw than in the lower jaw. Premolars in the lower jaw, that serve as abutment teeth for free‐end RPDs, tend to show lower values for the relative bone height.It is concluded that the differences between the three groups with regard to the periodontal support are small. The large amount of crowns and bridges in both the SDA and SDA and RPD groups, and the dental history of these subjects, resulting in SDA, should be taken into account. However, as indicated by the periodontal breakdown of premolars in some subjects with SDA, the combination of an existing severe periodontal involvement and a SDA is considered to be an unfavourable situation.
Occlusal force pattern during rhythmic human tapping movement
Authors: MUNAKATA Y. , TSUJI M. , KASAI S. 
Published: June 2007

SummaryThe dynamic occlusal force patterns associated with the performance of rhythmic tapping movement were analysed in normal subjects, who were instructed to make tapping movements at four frequencies, 2, 2.5, 3.3 and 5 Hz, with as constant a magnitude of force as possible. The occlusal force recorded by an intra‐oral customized device showed a triphasic pattern which could be divided into two components, and this pattern was more clearly defined during slower tapping movements. Of the two components, the first was relatively stable, regardless of changes in tapping frequency, while the second was highly dependent on the tapping cycle duration, and its duration was shortened with increases in tapping frequency. Furthermore, there was a significant correlation between the changes in the occlusal power phase and those in the burst duration of the masseter EMG simultaneously recorded by a pair of surface electrodes. On the basis of these findings, it is suggested that the tapping rhythm is modulated by the duration of the occlusal power phase and the associated jaw elevator muscle activity.
Effectiveness of fortnightly tooth brushing with amine fluorides in caries‐prone subjects
Authors: RAN F. , GEDALIA I. , FRIED M. , HADANI P. , TVED A. 
Published: June 2007

SummaryThe aim of this study was to assess the caries incidence and plaque accumulation in schoolchildren at caries risk, after brushing the teeth fortnightly with gels containing 0, 0.4% F, 1.25% F as amine fluoride (AmF) or the common amine fluoride toothpaste containing 0.125% F. The study was conducted double blind over an 18–month period, and after 6 months discontinuation of brushing. Only the group that brushed with the 1.25% AmF gel showed a significant decrease in caries development compared to the group that brushed with the 0.125% AmF toothpaste. During the 6‐month discontinuation period, the incidence of caries increased in all groups: the differences in caries development between all groups were not significant. Plaque indices were significantly lower in the AmF‐treated groups. The highest fluoride concentration in the gel reduced the development of caries to zero, probably due to increased fluoride levels in the oral milieu of caries risk children. In order to maintain a positive effect of fluoride over an extended time period, caries‐prone subjects should continue an initiated fluoride programme.
Functional stress modification after high condylectomy surgery
Authors: ALEXANDRIDIS C. , CAPUTO A.A. , ELIADES G.C. 
Published: June 2007

SummarySurgical removal of the head of the condyles inevitably leads to radical redistribution of loads applied to the mandible. The nature of this redistribution can have important implications on the surgical approach and subsequent reconstructive procedures. The purpose of this investigation was to visualize photoelastically the functionally delivered stresses after high condylectomy surgery. Three identical models of a dentate human mandible were constructed from a photoelastic material. One mandible simulated a unilateral and the other simulated a bilateral high condylectomy. The third mandible had both condyles intact and served as basis for comparisons. Silicone implants were placed on the sectioned condylar heads. The condyles, with the silicone implants, were fitted into simulated fossae and the mandibles were loaded unilaterally and bilaterally. The resulting stresses were observed and photographed in the field of a circular polariscope.Substantial differences in load‐generated stresses were observed as a result of both unilateral and bilateral condylectomies, compared to the normal case. The most severe stress conditions occurred with the unilateral condylectomy, where stresses associated with torsion were most evident.
Residual monomers (TEGDMA and Bis‐GMA) of a set visible‐light‐cured dental composite resin when immersed in water
Authors: TANAKA K. , TAIRA M. , SHINTANI H. , WAKASA K. , YAMAKI M. 
Published: June 2007

SummaryRods of a visible‐light‐cured dental composite resin were photo‐polymerized and immersed in water at 37°C for 7 days. The residual monomers (TEGDMA and Bis‐ GMA) trapped in the set composite and those eluted into water were analysed by gas‐liquid chromatography. It became evident that minor amounts of the residual monomers dissolved in water, but that most residual monomers remained in the set composite. Extension of the irradiation period contributed to the significant reduction in the residual monomer level and its elution into water.
Mandibular manipulation of anterior disc displacement without reduction*
Authors: JAGGER R.G. 
Published: June 2007

SummaryThe history and clinical symptoms of anterior temporomandibular joint disc displacement without reduction are characteristic, and include limitation of mandibular movement and mandibular deviation on opening of the mouth. Twelve consecutive patients attending a clinic with such symptoms were treated by mandibular manipulation. An immediate increase in the range of mandibular movement was obtained for all patients, with a mean increase in interincisal opening of 8mm. The method of manipulation is described, and the implications of the results for the treatment of TMJ patients are discussed.
Tooth enamel softening with a cola type drink and rehardening with hard cheese or stimulated saliva in situ
Authors: GEDALIA I. , IONAT‐BENDAT D. , BEN‐MOSHEH S. , SHAPIRA L. 
Published: June 2007

SummaryThe in‐situ remineralization effect of hard cheese was compared with that of saliva on tooth enamel in man. The intra‐oral test of softening enamel surfaces by a cola type drink followed by rehardening by chewing hard cheese and/or parafilm was assessed by microhardness and SEM measurements. Cheese consumption significantly increased the enamel hardness, whereas stimulated saliva did not have this effect. The remineralizing effects are presumably due to uptake of calcium and phosphate salts by the surface enamel. Morphologically, the enamel surfaces did not return to their original state.
Sex differences in signs and symptoms from masticatory and other muscles in 19‐year‐old individuals
Authors: KROGSTAD B. S. , DAHL B. L. , ECKERSBERG T. , ØGAARD B. 
Published: June 2007

SummaryPain and tenderness of masticatory muscles are often related to muscle tenderness elsewhere in the body. It has been shown that women are more prone to musculo‐skeletal disorders than men. We sought to determine whether sex differences of muscular symptoms were established by the age of 19. The subjects comprised 51 boys and girls who received a questionnaire regarding the function of their masticatory system, frequency of headache, and neck, shoulder and low back pain. Their masticatory system was examined, and neck and shoulders were palpated. For all variables in the questionnaire girls reported symptoms more often than the boys. Of the subjects 50% had tender chewing muscles upon palpation. Again the girls had the most. There was good correlation between reports of pain in one area as compared to others. The number of clinically tender neck and shoulder muscles correlated with the number of tender masticatory muscles. It was concluded that girls presented more muscular symptoms than boys.
Complete mandibular denture stability when posterior teeth are placed over a basal tissue incline
Authors: JOOSTE C.H. , THOMAS C.J. 
Published: June 2007

SummarySix patients with previous denture experience were provided with new dentures. Metal indicators were placed on either side of the mandibular denture and a cobalt‐chromium alloy marker was inserted in the left bucco‐posterior area of the mandible in each case. In the new dentures posterior teeth were positioned up to the retro‐molar pad, over the basal tissue slope of the posterior mandibular alveolar ridge. After habituation had taken place, a cineradiographic recording was made of chewing. Prior to the second recording the mandibular teeth were removed to a point where the remaining teeth were not over inclined residual alveolar ridges. Denture movement was observed by measuring the distances between the markers on an analytical projector. The results show a significant difference between the cranial values of the two chewing experiences. Values for all denture movements were less after removal of the teeth over an incline. These results support the clinical observation that teeth placed over a basal tissue incline have a destabilising effect during complete mandibular denture function.
Longitudinal study on occlusal force distribution in lower distal‐extension removable partial dentures with circumferential clasps
Authors: OGATA K. , MIYAKE T. , OKUNISHI M. 
Published: June 2007

SummaryIn this study, longitudinal changes of the occlusal force distribution ratio were examined in lower distal extension removable partial dentures with cast circumferential clasps. Occlusal force applied to the denture base and forces transmitted to the retainers were measured on several separate occasions from the insertion of new dentures to about 4 months after. Two rates of loading were chosen. One was simulated mastication (fast loading rate) and the other was 10 Ns‐1 (slow loading rate). Location of the loading points were first premolar (PI), second premolar (P2) and first molar (P3) of the denture. The occlusal force distribution ratio to the retainers was calculated when a load of 20N was applied to the loading point.The results are summarized as follows: (1) The occlusal force distribution ratio at fast loading rate on P1 and P2 was changed until 1 or 11/2 months after the insertion of the new dentures, and then became constant. This constant value was 30% on P1, 20% on P2 and 10% on P3. (2) Slow loading rate produced a greater ratio than the fast loading rate on P2 and P3 while there were no remarkable differences in the ratio between both loading rates on P1.
The recording and analysis of EMG and jaw tracking. I the recording procedure
Authors: HOWELL P. G. T. , JOHNSON C. W. L. , ELLIS S. , WATSON I. B. , KLINEBERG I. 
Published: June 2007

SummaryA computer‐based system is clescribccl which records and analyses electromyographic (EMG) signals and tracking data for mandibular movements during function! EMG signals were obtained bilaterally from six muscles and ii Sirognathograph monitored the postion of the lower incisor teeth in three dimensions. Directed jaw movement tasks by subjects were monitored These data were continuously sampled at a rate of 1 KHz per channel oven an operator controlled period.Analysis of the data was performed off‐line following the experiment. Individual chweing cycles associated with masticatory function were identified and the timing and dimensions of each chewing envelope established Corresponding EMG values were also determined and displays of EMG and jaw movement were plotted on a common time base an average chewing cycle and correlated EMG activity could also be displayed on a high resolution monitor and plotted for a hard copy to enable a comparison to be mad between subjects with and without jaw dysfunction.
Bending strength of Fuji® and Ketac® glass ionomers after sonication
Authors: ARCORIA C.J. , BUTLER J.R. , WAGNER M.J. , VITASEK B.A. 
Published: June 2007

SummaryGlass ionomer cements mixed by conventional methods contain voids that can decrease their overall strength. This study evaluated the effect of sonication on the reduction of air entrapment by measuring the bending strength in glass ionomer cements (Fujj‐II® and Ketac‐fil®). Glass ionomer cement was placed in identical‐test vials and sonicated for 45s, 10s, or 0s. The bending strengths were measured (0.005 in min−1) after setting times of 1 or 2 weeks. Mean bending strengths (MPa ± SD) for the 12 treatment both cements (P<0.001) and sonication times (P<0.001). The effect of setting time produced minimal increases in bending strength (P<0.218). The sonication of freshly mixed glass ionomer cements is a possible solution for reducing voids to increase bending strength.