bluuebunny/crossref_metadata_2025_split huggingface dataset:
The relative movements of the chin and the mandible during chewing
Authors: JEMT TORSTEN , HEDEGÅRD BJORN 
Published: June 2007

SummaryThe suitability of the soft tissue over the chin as a reference point in studies of mandibular performance during chewing was investigated. The movements of reference diodes (LEDs), one on the chin and the other attached to a lower front tooth, were registered simultaneously using the Selspot system and analysed in relation to the reference system in this method.With respect to chewing rhythm, the conformity of the behaviour of the two diodes‐or the two tissue locations‐was good, thus allowing the conclusion that a chin reference point is suitable for analysing chewing rhythm.Vertical displacement and velocity were less marked with the chin reference than with the tooth reference, however, indicating that the skeletal part of the mandible moves within the tissues envelope. The difference in movement at maximal opening was significant, the magnitude of the difference being between 12 and 20%.Lateral displacement seemed to be of similar magnitude, although a tendency towards larger movements of the chin point than of the tooth was found.
Subjective and objective evaluation of bruxing patients undergoing short‐term splint therapy
Authors: MEJIAS JUDITH E. , MEHTA NOSHIR R. 
Published: June 2007

SummarySubjective and objective criteria were utilized to evaluate the effectiveness of short‐term bite splint therapy on bruxistic behaviour. A simple bruxism monitoring device was used to check pre‐treatment and post‐treatment nocturnal bruxism. This preliminary study suggests that short‐term splint therapy is effective in eliminating mild to moderate facial pain and dysfunction while reducing bruxistic behaviour. The bruxism monitoring device is a simple and effective tool for diagnosing bruxism quantitatively.
Computer‐analysed movements in three dimensions recorded by light‐emitting diodes
Authors: JEMT TORSTEN , LSSON STIGKAR 
Published: June 2007

SummaryMandibular movements recorded by means of intraorally placed light‐emitting diodes (LEDs) were described and tested. By using a reference system attached to the test subject, the influence of head movements on the registration of the mandibular movements could be avoided. The errors of the method were tested. The stability of the reference system during function was found to be greater when the light impulses did not have to penetrate the lip.A limited clinical test was performed and the following observations were made: the mean cycle duration was, after the first cycles, stable through the whole chewing phase, 0.52 s when chewing crispbread; the duration of the occlusion phase appeared to be shorter than that of the opening and closing phases; the velocity of the mandible was greater in the opening phase than in the closing phase, with a mean velocity of 84 and 70 mm/s respectively; the clinical test showed that the method was easy to handle in the clinical situation, thereby creating an instrument for studies in larger groups of patients. By adding a simple computer program, the manual analysis could be reduced considerably and a number of variables could be measured with a high degree of precision.
EDTA enhancement of strontium uptake by intact human enamel
Authors: FRIEDMAN MICHAEL , HIRSCHFELD Z. 
Published: June 2007

SummaryThe aim of this research was to study the effect of EDTA on the strontium uptake by intact tooth enamel.EDTA did not significantly affect the strontium uptake in an acid medium of pH 4.5. However, it caused a sharp rise in strontium uptake at pH 6.0. At such a pH, the stability constants of the Ca‐EDTA complex are approaching a maximal value, and as a result of it a significant dissolution of the surface enamel, accompanied by a highly effective increase of the contact area for strontium uptake, is taking place. In all the experiments, treatment with strontium solution resulted in a decrease of the solubility and dissolution rate of enamel in an acidic environment.The resistance of enamel to acid attack was proportional to the quantity of absorbed strontium, reaching maximal values after treatment with strontium solutions in 10−2 M EDTA at pH 6.0.
Staining of composite resins by cigarette smoke
Authors: RAPTIS C. N. , POWERS J. M. , FAN P. L. , YU R. 
Published: June 2007

SummaryTwo conventional composites and one microfilled composite were exposed to cigarette smoke in vitro in a smoking chamber. Colour parameters were measured using reflectance spectrophotometry. The conventional composites showed more extensive staining than the microfilled composite. The stains were effectively removed by extensive cleaning.
Prevention of microleakage into experimental cavities in teeth: an in vitro study
Authors: THE G. S. T. , VAN MULLEM P. J. , PLASSCHAERT A. M. 
Published: June 2007

SummaryDye penetration into cylindrical, 1 mm diameter cavities in forty‐nine extracted human teeth was studied. Twenty‐eight teeth were filled with Cavit‐W or gutta percha and the remainder were left unfilled. The enamel surrounding all cavities was etched and the cavities sealed with three types of sealants. After 8 weeks, during which the temperature of the teeth was changed twice daily, Estilux appeared to have prevented the dye from penetrating into the cavities.
Correlations between EMG jaw muscle activity and facial morphology in complete denture wearers
Authors: TALLGREN A. , HOLDEN S. , LANG B. R. , ASH M. M. 
Published: June 2007

SummaryIn a sample of fifteen partially edentulous subjects assigned for immediate complete denture treatment, a correlation analysis was performed between pre‐extraction facial morphology determined from lateral cephalograms, and EMG activity of the anterior temporal and masseter muscles in maximal clench and tapping of teeth. Marked correlations observed between vertical and sagittal jaw relations and mean voltages of the jaw‐closing muscles indicated strong biting activity in subjects with a square facial type. No significant associations were observed between biting strength and the age of the subjects.Correlations between facial morphological changes and changes in EMG biting activity after denture insertion and during 1 year of denture wear indicated that the anterior temporal muscles were extremely sensitive to sagittal changes in anterior occlusion. The masseter muscles were less sensitive, but responded in some instances to changes in vertical jaw relationship.
The use of biofeedback to obtain jaw‐muscle relaxation in denture‐wearing subjects
Authors: YEMM R. 
Published: June 2007

SummaryA group of ten edentulous patients, who had experienced persistent soreness of the mucous membrane underlying their lower dentures, have been shown to exhibit a tendency towards greater activity of the temporal muscle while ostensibly at rest, compared with a number of normal subjects. A biofeedback technique, based on electromyography, proved effective in teaching the patients to relax during an experiment of approximately 20 min duration. In contrast relatively little change could be achieved by the normal subjects. It is concluded that the results support the hypothesis that muscle tension may contribute to lower denture discomfort, and suggest that biofeedback muscle relaxation training may be a useful method of treatment in such cases.
An investigation of the process of casting cores on to preformed wrought dental posts
Authors: TURNER C. H. , WILLOUGHBY A. F. W. 
Published: June 2007

SummaryThe casting of gold on to wrought ‘Wiptam’ and ‘G.T.’ posts has been investigated. Notching of ‘Wiptanm’ posts gave rise to grain structure rearrangement; carbon deposits from the wax burn were retained in the notches and prevented complete filling by the gold. Serious cracks developed from these notches when the core was cast on centrifugally but only slightly when Solbrig's method was used. These cracks explain why ‘Wiptam’ posts occasionally fracture.The above problems were not encountered with the ‘G.T.’ post, which has inbuilt retention channels, and allows a more complete burn out of the wax pattern.
Influence of auriculotemporal nerve anaesthesia on the masseteric silent period
Authors: SMITH D. M. , ZITER W. D. , MOHL N. D. , McCALL W. D. 
Published: June 2007

SummarySilent periods were evoked from the masseter muscles bilaterally in response to chin taps during a clench. Injection of 0.75 ml of 3% Mepivicaine posteromedial to each condyle led to a distribution of skin anaesthesia consistent with the distribution of the auriculotemporal nerve. Silent periods were evoked prior to and during anaesthesia in ten subjects.The silent period latencies (mean ± standard deviation) prior to anaesthesia were 12.5 ± 1.8 ms and 11.9 ± 2.5ms in the right and left masseters. During anaesthesia the latency decreased by 0.3 ± 1.3 ms in the right masseter and by 0.3 ± 2.1 ms on the left masseter. Neither change was statistically significant (P > 0.05).The silent period durations prior to anaesthesia were 20.3 ± 4.0 ms and 22.8 ± 7.1 ms in the right and left masseters. During anaesthesia, these decreased by 2.74 ± 5.8 ms on the right and 2.15 ± 4.4 ms on the left. These decreases were not statistically significant (P > 0.05).These results failed to demonstrate an influence of the predominant nerve supply of the TMJ on either the latency or the duration of the masseteric silent period.
Surface treatment studies aimed at streamlining fissure sealant application
Authors: MAIN C. , THOMSON J. L. , CUMMINGS A. , FIELD D. , STEPHEN K. W. , GILLESPIE F. C. 
Published: June 2007

SummaryThree laboratory studies were carried out with the aim of improving or streamlining enamel surface treatment procedures in fissure sealing.In Study 1, the effect of reducing acid etch time from 60 s to 10 s was assessed by SEM and tensile bond strength measurements. Reduction in etch time produced a finer etch pattern, gave a reduced but still high, bond‐strength, albeit with slightly poorer long‐term adhesion.Study 2 showed that a conventional acid etch treatment could completely remove acquired pellicle, without prior prophylaxis. SEM studies and bond‐strength measurements corroborated this view.In Study 3, compressed air and chemical drying agents were compared for drying speed and efficiency. Compressed air gave more rapid, thorough drying, and greater resultant bond strengths.
Long‐term dimensional stability of three current elastomers
Authors: CLANCY JAMES M. S. , SCANDRETT FORREST R. , ETTINGER RONALD L. 
Published: June 2007

SummaryThe long‐term dimensional stability of three non‐aqueous elastomeric impression materials, a silicone, a polyether and a polysiloxane, were investigated. The testing apparatus was an A.D.A. specification No. 19 test block and mould. The impressions were measured by the use of a travelling stage reflecting microscope and a Quantimet 720 Image Analyzing computer at time zero and again at 4, 24 and 48 h, and at 1, 2, 3 and 4 weeks.Impressions poured immediately had the greatest accuracy for all the materials. The polysiloxane (0.025 mm) and polyether (0.033 mm) showed very little change in dimension after 4 weeks when compared to the test block. However, the silicone showed significant change at 4 h (0–14 mm) and 0–2 mm after 4 weeks. After 4 weeks the polysiloxane maintained the best surface detail, the polyether was adequate but the silicone lost much of its detail in as little as 24 h. The reasons for these findings are discussed.
Variations in the particles produced at the end of mastication in subjects with different types of dentition
Authors: JIFFRY M. T. M. 
Published: June 2007

SummaryThe final composition of the size of particles of food or the swallowable composition (SC) has been investigated in subjects with different types of dentition. A convenient mouthful of hard‐baked soya beans was masticated and thereafter the bolus was dried, sieved and weighed. Full denture wearers prepared a SC with a mode value around 4000 μm whereas subjects with mixed dentition prepared a SC with a mode value around 2000 μm. Subjects with partial dentition produced wide variations in the SC. To produce a SC which is usually swallowed by a particular subject the quantity of masticated food should bear an optimum ratio to the area of the healthy oral tissues.
The relationship of occlusal wear to occlusal contact area
Authors: RUSSELL M. D. , GRANT A. A. 
Published: June 2007

SummaryIt has been suggested that masticatory efficiency is directly related to the area of the occlusal surfaces that make contact. However, little work has been carried out to determine if occlusal wear increases the area of contact, and controversy exists as to whether this would be an advantage. Using a wax registration method, occlusal contact area was measured in a group of individuals with either local or generalized wear, before and after treatment. The changes in occlusal contact area were statistically significant for the group exhibiting generalized wear but not for the group exhibiting localized wear.
Denture aesthetics: an evaluation of laymen's preferences
Authors: MARUNICK M. T. , CHAMBERLAIN B. B. , ROBINSON C. A. 
Published: June 2007

SummaryThe purpose of this study was to evaluate whether the lay public perceives anterior teeth selected by Williams's typal matching method as aesthetically pleasing. The theory was tested by laymen responding to questions about photographs of three edentulous male and three edentulous female patients. These patients were selected as representatives of square, tapering, and ovoid facial forms. The photographs were portrait views of the patients wearing different dentures displaying square, tapering, and ovoid teeth.Substantiation for typal match was found in the square female, square male, and the ovoid female patients. Responses to the photographs demonstrated a preference for square tooth forms over ovoid, and then tapering. Overall, ovoid teeth were preferred for females and square teeth were preferred for males.
Investigation of hydrostatic pressure changes during cementation of screw‐retained posts, and posts with integral cement release channels
Authors: TURNER C. H. , GROSS M. J. 
Published: June 2007

SummaryIntra‐radicular pressures during the cementation of screw‐retained posts have been found to reach 1.5 × 104 KN/m2 when cement is inserted into the prepared post hole or no pressure, indicating that an incomplete cement lute had developed, when the post was coated with cement. The effectiveness of cement channels was investigated and for the traditional single channel, using the cement ‘insertion’ method, there was an intra‐radicular pressure of 8.5 × 104 KN/m2, compared with 1.1 × 104 KN/m2 for the corresponding round post. Multiple cement release channels* gave an enhanced pressure reduction to 2.0 × 103 KN/m2.
Relationship between creep, γ2, and marginal fracture of dental amalgams
Authors: SARKAR N. K. , EYER C. S. , NORLING B. K. 
Published: June 2007

SummaryThe effect of γ1 and γ2 on the creep deformation of dental amalgams has been investigated. It has been shown that the creep of a conventional amalgam is not dependent on γ1 as was previously reported. Rather it is strongly influenced by γ2 and its volume fraction. It has been speculated that Sn‐rich grain boundaries also enhance creep by facilitating grain boundary sliding. The reported correlation between creep and marginal fracture has been explained in terms of this dependence of creep on corrosionprone Sn‐rich microstructural constituents of amalgams.
Serum creatine kinase studies in mandibular pain dysfunction
Authors: COX P. J. , ROTHWELL P. S. 
Published: June 2007

SummaryA biochemical test for muscle damaghe (serum creatine kinase estimation) was used to investigate twenty‐six normal subjects, nine normal subjects following experimental bruxism and twenty‐seven patients suffering from mandibular pain dysfunction. No significant differences in serum creatine kinase levels were detected between any of the groups.
Antiplaque properties of sustained release SnF2: pilot studies
Authors: SWANSON T. D. , TINANOFF N. 
Published: June 2007

SummaryPilot studies examining the physical and clinical properties of an intracoronal sustained release fluoride delivery system were performed. After testing various percentages of SnF2 incorporated into polycarboxylate, zinc phosphate, and zinc oxide cements, 70% SnF2 polycarboxylate cement was found to have adequate compressive strength while releasing the greatest amount of fluoride in vitro.A 30‐day in vivo trial, in which this fluoride cement was used as a temporary intracoronal restoration, produced elevated salivary fluoride levels with only transient elevation in urinary fluoride levels. Plaque scores decreased during the experimental period, suggesting that the released SnF2 affected bacterial growth or attachment. The SnF2‐polycarboxylate cement was an adequate temporary restorative material without significant side effects.
Influence of chin tap force and bite force parameters on the duration of the electromyographic silent period
Authors: McCARROLL R. S. , NAEIJE M. , ZORN H. 
Published: June 2007

SummaryControversy exists as to whether chin tap force and bite force affect the duration of the electromyographic silent period following the jaw jerk reflex during isometric contraction of the elevator muscles of the mandible.This study demonstrates that statistical trends exist showing increased silent period duration for increased tap forces and decreased silent period duration with increased bite forces.
Quantitative cement solubility experiments in vivo
Authors: PLUIM L. J. , ARENDS J. , HAVINGA P. , JONGEBLOED W. L. , STOKROOS I. 
Published: June 2007

SummaryThe dissolution and dissolution rate of dental luting cements was measured longitudinally. Cement samples in enamel were placed in a full prosthesis and worn in the mouth for up to 6 months. At given intervals, replicas of the cement surfaces were made and quantified by means of SEM stereographic photographs. With a stereometer the distance between cement surface and original enamel surface can be determined quantitatively. The results show in vivo solubility rates for zinc‐phosphate and glass‐ionomer cement of about 80μ week−1 and 2μm week−1 respectively.
An investigation into the type of union achieved between cast cores and Wiptam wire posts
Authors: AHMAD M. , JONES J. C. GLYN 
Published: June 2007

SummaryThe type of union formed between Wiptam wire posts and cast cores has been investigated.Scanning electron microscopy of sectioned ‘as cast’ specimens showed that the union between Wiptam posts and cast cores was predominantly mechanical in nature.Diffusion studies, however, using an X‐ray Microanalysis Unit, revealed that there was evidence of diffusion of silver atoms into the post from the core. This suggests that the bonding between the two components is not merely a simple mechanical lock.
Influence of experimental interfering occlusal contacts on the activity of the anterior temporal and masseter muscles during mastication
Authors: RIISE C. , SHEIKHOLESLAM A. 
Published: June 2007

SummaryQuantitative electromyography (EMG) was used to study, in eleven volunteers with complete, natural dentitions, the effects of an experimental intercuspal occlusal interference on the pattern of activity of the anterior temporal and masseter muscles during mastication.The results show that a small occlusal interference (about 0‐5 mm) in the intercuspal position can change the co‐ordination of muscular activity during mastication. In general, there was a prolonged contraction time as well as a reduction of the activity in all the investigated elevators, especially on the side of the interference. Furthermore, after 48 h several subjects preferred to chew unilaterally. After removal of the interference, the pattern of co‐ordination of muscular activity returned almost to the pre‐experimental pattern within 2 weeks.
Cumulative electromyography of the human masseter muscle during fatiguing isometric contractions
Authors: CHRISTENSEN L. V. 
Published: June 2007

SummarySix adult males performed maximum voluntary tooth clenching (MVC) for 10, 20, 30, 40 s and, after 15 min, for 40, 30, 20, 10 s. During the isometric exercises the electrical currents of the masseter muscle were sampled by integrated and cumulative surface electromyography. Subjective masseter fatigue was present after 30 and 40 s of MVC clenching, accompanied by changes in myoelectrical activity. Strength testing of the masseter muscle, before and after endurance testing, showed that the strength increased by a significant 16% following two endurance tests. This observation was explained by a post‐tetanic potentiation and/or a differentiated use of motor units in the fatigued muscle. It is concluded that brief MVC isometric activity, or strength testing, is not a reliable measure of fatigue in the masseter muscle when cumulative electromyography is used. Prolonged MVC isometric activity, or progressive endurance testing, monitors reliably the onset and progression of masseter fatigue.
The minimal width of the periodontal space
Authors: RALPH W. J. , JEFFERIES J. R. 
Published: June 2007

SummaryRadiographs of horizontal serial sections of dentate human mandible disclose a picture of the periodontal space, the bony margin of which is highly irregular. The minimal width of this space was measured at four points roughly 90° apart and the average minimal width obtained.It is suggested that the usual clinical radiographic picture of the periodontal space of a particular tooth or teeth is such that a judgment of the width of the space cannot be made with any certainty.
Visco‐lelastic properties of four currently used tissue conditioners
Authors: DE MOT B. , DE CLERCQ M. , ROUSSEEUW P. 
Published: June 2007

SummaryAbout 60% of complete denture wearers experience a mostly painless inflammation of the palatal mucosal membrane. Especially prosthetic trauma and Candida albicans infection are assumed as aetiological factors. The treatment can be prosthetic or medicamentous, dependent on the cause. In this connection tissue conditioners could be very effective by their visco‐elastic properties.Four tissue conditioners have been examined (Coe Comfort, FITT, Ivoseal, Visco Gel) for their impression softness and elastic recovery. All tests have been done on 20 mm specimens. The length of the specimens was measured during a 10 min compression and a 60 min relaxation. Eight ageing times have been taken into consideration.From the results large differences appear between the various tissue conditioners. Two main groups can be distinguished. FITT and Ivoseal are harder materials, whereas Coe Comfort and Visco Gel are softer. The ageing time has a clear hardening influence especially on Visco Gel. Visco Gel appears to be the best tissue conditioner by its relative plasticity during the first hours and its elastic behaviour during a longer ageing period. The clinical relevance of these materials is certainly not proved by this study. Further research will show this.
Relationship of electromyographic parameters in jaw dysfunction patients classified according to Helkimo's index
Authors: McCARROLL R. S. , HONEE G. L. J. M. , NAEIJE M. 
Published: June 2007

SummaryForty‐two jaw pain‐dysfunction syndrome patients (PDS) were divided into three groups depending on the severity of their condition using the Helkimo clinical dysfunction index. For both the left and right masseter and anterior temporal muscles three parameters of their electromyographic activity were measured, the silent period (SP), the root mean square value (RMS) and the mean power frequency (MPF). During the experiments the patients were instructed to clench as hard as possible in the intercuspal position.No statistically significant differences could be found between the values for any of the muscles measured between the different Helkimo clinical dysfunction groups. However, when the affected side was compared with the unaffected side in this patient material, statistically significant longer silent period durations and greater RMS values were found in the masseter muscles of the affected side group.