bluuebunny/crossref_metadata_2025_split huggingface dataset:
A differential thermal analysis (DTA) for the heats of reaction and temperature rises produced during the setting of tooth coloured restorative materials
Authors: LLOYD C. H. 
Published: June 2007

SummaryDifferential thermal analysis (DTA) has been used to obtain the temperature rises produced during the setting of a range of tooth coloured restorative materials, which included silicates, glass ionomers and composites. These have been compared on the basis of the temperature rise per unit volume of material. Calibration of the areas under the reaction peaks (produced during this isothermal operation) to obtain heats of reaction is discussed and a method described. As for the temperature rises, values are given per unit volume of material. The results are compared with those reported in other studies from which DTA is seen to be a technique suited to the determination of these parameters and which might be considered for use a standard method.
Physiological reactions to stress in subjects with and without myofascial pain dysfunction symptoms
Authors: MOSS ROBERT A. , ADAMS HENRY E. 
Published: June 2007

SummaryMyofascial pain dysfunction syndrome and temporomandibular joint (TMJ) dysfunction syndrome have been suggested as resulting from masticatory muscle hyperactivity. Furthermore, this hyperactivity has been viewed as a response‐specific reaction to stress. The present study was designed to assess the effects of laboratory‐induced stress (i.e., startle stimulus, buzzer series, serial sevens tasks, and pain threshold/tolerance tests) on physiological responses (i.e. bilateral masseter EMG, skin conductance level, and heart rate) of ten patients (TMJ pain) with a history of facial pain and TMJ sounds. The two control groups, one with TMJ sounds only (TMJ sound) and the other with no history of these symptoms (non‐TMJ), were matched for sex and age. The results indicated that the TMJ pain group did not exhibit different masseter EMG levels when comparing symptomatic versus asymptomatic sides. Few significant differences were noted in the masseter EMG recordings of the TMJ pain and non‐TMJ group, while no difference occurred between the EMG levels of the TMJ pain and TMJ sound group. Little support was found for the assertion that TMJ pain subjects show greater EMG reactivity and less adaptation than do non‐TMJ subjects. Finally, no differences were found among groups in relation to the latency to ischaemic pain onset or tolerance. The discussion focuses on reasons for the findings of the present study being discrepant from previously reported research.
Analysis of factors influencing the long‐term effect of treatment of TMJ‐pain dysfunction
Authors: MEJERSJÖ CHRISTINA , CARLSSON GUNNAR E. 
Published: June 2007

SummaryA follow‐up study on 154 females was performed approximately 7 years after the start of treatment for TMJ pain dysfunction. At the follow‐up the function of the patients' masticatory system had on average greatly improved. The individual variation was great, however. In this paper the influence of such factors as diagnosis, age, general health, occlusal disharmonies, dentition and social environment on the long‐term effect of treatment was analysed.Patients with TMJ osteoarthrosis had, on average, no more signs or symptoms of dysfunction at the follow‐up than those judged to have had mainly neuromuscular problems. Poor general health was found to have a negative influence both on the immediate response to treatment of TMJ pain dysfunction and on the long‐term prognosis. Few correlations were found between occlusal factors and dysfunction. Occlusal interferences showed no correlation to dysfunction at the first examination and at the follow‐up were mainly correlated to some reported symptoms.Loss of molars and premolars was correlated to impaired TMJ‐function.The patients with repeated periods of treatment (14%) did not differ from the rest with respect to signs and symptoms of dysfunction at the follow‐up. In eight patients with extremely long periods of treatment general health problems and/or psychosocial factors were evident.
The effect of ultrasonic scaling on the surface of Class V amalgam restorations—a scanning electron microscopy study
Authors: RAJSTEIN J. , TAL M. 
Published: June 2007

SummaryClass V cavities were prepared on twelve extracted teeth and then filled with amalgam which was condensed in six cases by hand and six by mechanical means. SEM records were obtained before and after ultrasonic scaling of the restored area. They showed that such scaling had a deleterious effect on the surface of the amalgam and its marginal integrity. However the mechanically condensed specimens were less affected.
The hardness of composites as a function of temperature
Authors: GREENER E. H. , GREENER C. S. , MOSER J. B. 
Published: June 2007

SummaryThe microhardness of conventional, posterior and microfil composites were measured as a function of temperature in an aqueous environment. With the exception of one posterior composite and two microfils, the composites suffered dramatic decreases in hardness (of the order of 30–50%) over temperature intervals corresponding to that encountered in oral service. In those systems which did not display hardness changes, interactions between glass and matrix as well as enhanced filler packing may be important.
The in vivo corrosion of Dispersalloy
Authors: McTIGUE D. , BRICE C. , NANDA C. R. , SARKAR N. K. 
Published: June 2007

SummaryThe in vivo corrosion of Dispersalloy amalgam restorations was characterized by scanning electron microscopy and energy dispersive X‐ray analysis. It was observed that the corrosion of CuSn resulted in pitting on the restoration surface. Corrosion of Sn‐rich grain boundaries led to intergranular separation of γ1 grains. The tin released through corrosion reacted with Ca, P, Cl and O forming various insoluble complexes on the external surface, at the tooth‐amalgam interface, and within the interior of the restoration. The demineralization of the amalgam‐adjacent margin has been attributed to corrosion.
Attachment retained overdentures: a report on their maintenance requirements
Authors: SHAW M. J. 
Published: June 2007

SummaryTwenty‐three patients who received attachment retained overdentures between 1964 and 1977 are reviewed. One third of the patients examined had carious abutment teeth, oral hygiene was poor, and periodontal disease prevalent. Overdentures opposed by natural teeth required more extensive prosthetic maintenance than overdentures opposed by a conventional complete denture. Three quarters of the teeth retaining the prostheses were functioning adequately after a mean period of 7 years.
A 4 year follow‐up study of alveolar bone height influenced by two dissimilar Class II amalgam restorations
Authors: FISHER D. , MARKITZIU A. , FISHEL D. , BRAYER L. 
Published: June 2007

SummaryFifty‐four paired, approximal amalgam fillings, extended (E) versus unextended (NE) were placed in forty‐three patients and followed up to 4 years. Yearly measurements between the alveolar crest and (a) the apical margin of the fillings (E, NE), and (b) the cemento‐enamel junction of the control group, were performed using bite‐wing radiographs joined to a translucent grid magnified ten‐fold. The rate of alveolar crest resorption was similar for the control (C) and the unextended filling (NE) and reached 0.45 mm after 4 years of follow‐up. The resorption of the alveolar crest under the extended (E) filling was significantly higher and reached 0.80 mm after 4 years (P<0.001).
New sustained release dosage form of chlorhexidine for dental use: use for plaque control in partial denture wearers
Authors: HIRSCHFELD Z. , FRIEDMAN M. , GOLOMB G. , BEN‐YAACOV D. 
Published: June 2007

SummaryThe aim of this work was to test the effectiveness of a local sustained release application of chlorhexidine in prevention of plaque formation in a group of five partial denture wearers when oral hygiene procedures were withdrawn. The clinical study demonstrates that coating of the partial dentures with ethyl cellulose polymer containing the drug, prevents accumulation of plaque during a period of 12 days. No typical side effects of chlorhexidine such as tooth staining and unpleasant taste were observed during the study.
Microprobe analysis of dental amalgam alloy particles of Ag‐Cu eutectic composition
Authors: BRYANT R. W. 
Published: June 2007

SummaryAn electron microprobe was used to investigate the composition and microstructure of commercially available, and experimental dental amalgam alloy particles of approximately Ag‐Cu eutectic composition. The method of alloy and amalgam specimen preparation and the technique used in microprobe analysis have been briefly outlined. The dispersant particles in one commercial alloy were of Ag‐Cu eutectic composition (28.1% Cu), in another commercial alloy they were Cu‐rich (31% Cu). Although the dispersant particles were predominantly of uniform appearance, there was evidence in some particles of an internal structure pattern, small spherical inclusions or voids. The possible composition of the Cu‐rich inclusions was investigated using particles from an experimental alloy of approximately Ag‐Cu eutectic composition.
A method to determine the loss of substance of dental restorations
Authors: VRIJHOEF M. M. A. , LETZEL H. , HENDRIKS F. H. J. 
Published: June 2007

SummaryA method is described for quantitative in vivo wear measurements on Class I and II composite restorations. Class I gold inlays were made in an acrylic premolar and molar. Over the occlusal parts of the teeth cast silver caps were made after releasing the surface of the inlay with tinfoil. Wear on the restorations was simulated by grinding away some gold from the inlay. Silicon impressions of the teeth were made with the caps both before and after this simulation. The volume and the average thickness of the removed gold was measured from the weight of the enclosed impression material in the cap before and after the wear simulations, the density of the tinfoil and the impression material as well as thickness and the weight of the tinfoil‐release.Values expected for the volume and the average thickness of the removed gold were calculated from the weight of the restored acrylic teeth before and after the wear simulation, the weight, the density and the thickness of the tinfoil and the density of the gold used for the inlays. Measured and expected values are linearly correlated (r=0.97). An average wear thickness of the occlusal surface of a particular tooth of at least 30 μm can be detected. Because of its simplicity, inexpensiveness and accuracy the wear measurement method is highly productive and suitable for large scale and long‐term clinical research on the wear behaviour of posterior composites.
Results of epidemiological examinations of the temporomandibular joint in adolescents and young adults
Authors: GROSFELD O. , JACKOWSKA M. , CZARNECKA B. 
Published: June 2007

SummaryAn epidemiological investigation of the temporomandibular joint in 800 persons was undertaken, including two groups of 400 persons aged 15–18 and 19–22 years. The numbers of boys and girls was about the same. Interview and clinical examination comprised morphological and functional features of the stomatognathic system. The TMJ examination carried out included mandibular movements, pain and sound symptoms. The results of the examinations were noted, counted by electronic methods and statistically analysed. From the material, two groups were selected: without TMJ symptoms (OTMJ group) and with TMJ disorders (TMJ group). TMJ disorders were evident in 67.62% of the examined persons and this was common to both age groups. In groups with TMJ disorders a significant incidence of girls was found. In groups with TMJ disorders the number of statistically significant pathological features in the stomatognathic system increased with age. TMJ disorders appeared in both age groups in various forms, separately or in combination, with different frequency. With reference to the number and kind of symptoms obtained on interview and/or on clinical examination, four degrees of intensity of TMJ disorders have been defined and their incidence discussed.
An alternative method for recording the occlusion of the edentulous patient during the construction of replacement dentures
Authors: DUTHIE N. , YEMM R. 
Published: June 2007

SummaryAn alternative method of recording the occlusion for the edentulous patient is described. The method is applicable to situations where replacement dentures are to be prescribed. In place of conventional record blocks, shellac‐based wax replicas of the existing dentures are used. Such record blocks facilitate both retention of satisfactory features of the existing dentures and also the incorporation of specific modifications.
The effectiveness, in vitro, of miconazole and keteconazole combined with tissue conditioners in inhibiting the growth of Candida albicans
Authors: QUINN D. M. 
Published: June 2007

SummaryTwo recent antifungal agents, miconazole and ketoconazole, were combined with three tissue conditioners and tested in vitro for their effects on the growth of Candida albicans. Studies for comparison were carried out using the earlier antifungal agents, amphotericin B and nystatin. Miconazole and ketoconazole were as effective as nystatin in completely inhibiting the growth of Candida albicans. The ineffectiveness of amphotericin B when combined with tissue conditioners as an antifungal agent was confirmed. (See Addendum p.181.).
Mandibular dysfunction in 10–18 year old school children as related to morphological malocclusion
Authors: LIEBERMAN M. A. , GAZIT E. , FUCHS C. , LILOS P. 
Published: June 2007

SummaryAn association was sought between certain morphologic characteristics of malocclusion—Angle classification, over‐bite, over‐jet, open‐bite, cross‐bite and crowding—and the presence or absence of three cardinal symptoms of mandibular dysfunction—joint sounds, joint sensitivity to palpation and muscle sensitivity—in a sample of 369 1 school children. In addition, two additional independent variables, ‘occlusa, wear’ and ‘previous orthodontic treatment’ were introduced into the statistical analysis.Occlusal wear and abnormal overbite were the only factors found to increase significantly the presence of dysfunction symptoms.
The disc of the human temporomandibular joint: design, function and failure
Authors: OSBORN J. W. 
Published: June 2007

SummaryThe directions and limits of mandibular movements are controlled by muscles and nerves, and by biomechanical constraints in the dentition and the temporomandibular joints with their associated ligaments. This paper analyses biomechanical constraints in relation to shape, function, stability and dysfunction of the disc in the joint. It is argued that the dense part of the disc is modelled in response to condylar forces which compress it into the articular eminence thereby thinning its centre and squeezing out a thickened anulus around its rim. Because of a lack of congruence between the two articulating surfaces of the joint and a very low coefficient of friction, the disc is potentially squeezed off the condyle by compression forces during opening, closing and mastication. It is stabilized mainly by its anulus whose thick rim isunable to prolapse between the condyle and articular eminence. An important function of the elastic tissue behind the thick part of the disc may be, by contracting, to prevent the soft tissues behind the joint being nipped between the condyle/disc/temporal bone when the jaw is closing. The author suggests that during mastication the function of the disc is not only to spread the joint forces but also to limit the depth to which the condyle is compressed into the soft tissues covering the temporal bone and thereby allow the condyle (and disc) sufficient freedom to spin and slide over the temporal bone without distorting and damaging the surfaces. In other words, the function of the disc is to destabilize the condyle. In terms of biomechanical constraints the disc seems more liable to prolapse anteriorly than posteriorly. It prolapses when the compression forces which tend to wedge it off the condyle cannot be resisted by its thickened anulus. If the energy of compression is stored within the distorted disc and suddenly released there is an audible click.
Wear patterns of composite restorative resins in vivo; observations by scanning electron microscopy
Authors: HENGCHANG XU , TONG WANG , SHIQING SONG 
Published: June 2007

SummaryIn this study, the wear pattern of seven commercial composite resins, one experimental composite and one dental amalgam were investigated. These materials were separately inserted in a separation preparation cavity of the patient's mouth. After clinical service for 3, 9 and 12 months the specimens were taken out and observed by scanning electron microscopy (SEM). It was found that the softer resin matrix wore away first while the inorganic filler particles showed no signs of abrasive wear, whereafter filler particles were loosened once there was no support of the resin matrix around them.
Methodological aspects in clinical evaluation of cast restorations with colour slides
Authors: MEZGER P. R. , VAN T'HOF M. A. , LETZEL H. , ESCHEN S. , LEEMPOEL P. J. B. , SNOEK P. A. , VRIJHOEF M. A. 
Published: June 2007

SummaryIn a methodological investigation colour slides were used for the clinical evaluation of crowns. Four criteria, described in a criteria list or recorded by means of reference slides, were used. In assessing the clinical characteristics of crowns to a certain extent colour slides turned out to be a useful instrument. Shortcomings of the method are discussed and improvements are suggested.
The application of a duplication technique in post‐surgical Prosthodontics
Authors: ORR M. T. S. 
Published: June 2007

SummaryIn the management of patients with acquired defects of the palate, continuity between immediate and intermediate stages of obturation has always posed a major problem. This is because the intermediate obturatior is required as early in the post‐surgical phase as possible, consistent with minimum interference to the healing tissues and minimum trauma to the patient. This paper describes a technique, which helps to overcome the problem.
A retrospective analysis of the treatment of occlusal disharmony by selective grinding
Authors: WINSTANLEY R. B. 
Published: June 2007

SummaryThe method of treatment by the author of twenty patients with the signs and symptoms of occlusal disharmony over a 2 year period are described. The majority of patients attending for recall had partial or complete resolution of symptoms. The number of patients treated was insufficient for any definite conclusions to be reached concerning this method of treatment, although it was observed that loss of first molar teeth and the presence of third molar teeth in a number of patients could be aetiological factors.
Occlusal force pattern during chewing and biting in dentitions restored with fixed bridges of cross‐arch extension
Authors: LUNDGREN D. , LAURELL L. 
Published: June 2007

SummaryThe pattern of axially (perpendicular to the occlusal plane) directed occlusal forces developed during light tooth tapping in habitual occlusion, chewing, swallowing and maximal biting was studied in twelve subjects whose dentitions were periodontally treated and prosthetically restored with cross‐arch bridges with unilateral posterior two‐unit cantilevers.The measuring devices consisted of four strain‐gauge transducers uniformly and bilaterally mounted in pontics of maxillary bridges to represent the posterior (end abutment and distal cantilever respectively) and anterior regions. Thus, the forces could be studied locally in various parts of the dentition simultaneously as well as totally over the entire dentition.The results demonstrated that the distal cantilever unit, on average, was subjected to forces about or less than half of those over the contralateral end abutment unit irrespective of the activity studied. Furthermore, the cantilever forces either equalled or were even significantly smaller than those of the anterior regions.All subjects preferred the end abutment side as the chewing side. When the cantilever side was used as the chewing side, which occurred most infrequently, the bolus was usually located in the anterior region.The mean total chewing force (about 50 N) was only about half of that found in a previous study of subjects supplied with cross‐arch bridges with bilateral end abutments (Lundgren & Laurell, 1985). Furthermore, on average only 26% of the voluntary muscular capacity was used during chewing, compared with 37% in the ‘bilateral end abutment group’ referred to.The reasons for the comparably small forces over the distal cantilever unit and the lower muscular utilization during chewing in cross‐arch bridges with unilateral posterior two‐unit cantilevers as well as the implications of the findings for the dimension of such bridge constructions are discussed.
Laboratory studies of visible‐light cured fissure sealants: setting times and depth of polymerization
Authors: STRANG R. , CUMMINGS A. , STEPHEN K. W. 
Published: June 2007

SummaryMeasurements were made, using an acoustic transmission method, of the setting times of three visible‐light curing sealants (two filled, one unfilled). Five commercially available visible‐light polymerizing sources were tested with each material. Only three of the light sources gave setting times not significantly different from the manufacturers' recommended times for all three materials tested.The variation in microhardness with depth of sealant was measured to study the depth of polymerization of the sealants, all of which were adequate. The filled sealants had microhardness values greater than the unfilled sealant, at all depths studied.
Assessment of microleakage of restorative materials by a diffusion model
Authors: SHEN C. , HERRIN K. 
Published: June 2007

SummaryThe time‐dependent microleakage behaviour of two types of restorative materials, a microfilled composite resin and a glass ionomer, was studied. A dentine bonding agent was also included. This study was based on a diffusion model of microleakage. It was found that the initial gap sizes of the restorations increased progressively for restorations microfilled with bonding agent, microfilled alone, and glass ionomers, in that order. Analysis of microleakage over some periods suggests that the gap size of the restorations by microfilled with bonding agent may increase with time, and that while restorations by glass ionomer and microfilled composite resin decrease in gap sizes with time, glass ionomer restorations show a faster rate of decrease.
Heat treatment, microstructure and corrosion of a low‐gold casting alloy
Authors: STRUB J. R. , EYER C. S. , SARKAR N. K. 
Published: June 2007

SummaryThe aim of this study was to understand the relationship between heat treatment, microstructure and corrosion of a low‐gold casting alloy. Potentiostatic and potentiodynamic polarization techniques were used to evaluate the chloride corrosion resistance of the alloy in the following conditions: (A) as cast, (B) bench cooled, (C) homogenized, (D) homogenized and aged for 2 h, and (E) homogenized and aged for 4 h.The microstructure of each sample, before and after corrosion, was examined by optical and/or scanning electron microscopy. In general, heterogeneous structures containing dendritic segregations and precipitates were found to be more prone to corrosion than the single phase solid solution structure produced by homogenization. On the basis of the potentiodynamic polarization data, the samples were ranked as follows: C>D>B>A>E, C being the most corrosion resistant structure.