bluuebunny/crossref_metadata_2025_split huggingface dataset:
The abrasion of acrylic resin by cleaning pastes
Authors: HEATH J. R. , DAVENPORT J. C. , JONES P. A. 
Published: June 2007

SummaryThe physical removal of plaque from dentures by brushing is important in the maintenance of oral health. However, there is a danger that brushing will abrade acrylic resin. A machine using a rotary brushing action was therefore utilized for laboratory tests of possible cleaning pastes, employing a toothbrush with good access and adaptability to denture surfaces. Crest toothpaste produced the most abrasion on acrylic resin, Dentu‐Creme the least. An experimental paste produced an appreciably lower abrasion rate. Self‐cured specimens wore more than heat‐cured ones. The rate of abrasion decreased as the temperature was raised. Brushing with water alone, or with a 10% solution of soap, did not produce detectable wear.The wear produced by proprietary cleaners when hand brushing the lingual flanges of dentures and flat blanks of heat‐cured acrylic was also measured. Boots denture cleaning paste produced the greatest abrasion, Dentu‐Creme the least. The wear measured by reference to a glass plane was at least twice that recorded by the decrease in depth of a groove. The machine did not quantitatively produce the same abrasion as hand brushing, nor did it qualitatively rank the pastes in the same order of abrasiveness.The clinical relevance of these results is discussed.
Intra‐radicular hydrostatic pressure changes during the cementation of post‐retained crowns
Authors: GROSS M. J. , TURNER C. H. 
Published: June 2007

SummaryThe intra‐radicular hydrostatic pressures generated during the cementation of parallel‐sided dental posts have been measured. Pressures are generated only when cement is inserted into the prepared post hole. Using zinc phosphate cement, with posts placed 2 min from the commencement of mixing, pressure has been shown to depend on post diameter, the closeness of fit, and the powder‐liquid ratio. The maximum pressure recorded was 1.7 × 104 kN/m2 using a 1.3 mm diameter post, a mean cement film thickness of 37 μm, and an ideal powder‐liquid ratio of 3.0. Pressures similar to that generated using zinc phosphate cement were recorded when black copper phosphate was used as the lute, but zinc polycarboxylate generated less pressure, and an ortho‐ethoxy benzoic acid cement markedly less pressure.Before it is possible to confirm the ideal luting cement for posts, further studies of the effectiveness of cement release channels, and post retention. are necessary.
Geographic comparisons of the incidence of dental erosion: a two centre study
Authors: XHONGA FRIDA A. , VALDMANIS SILVIA 
Published: June 2007

SummaryThis study revealed that the premolars in both arches are most commonly afflicted with erosion. The same results were obtained in an earlier study conducted by Sognnaes, Wolcott & Xhonga (1972) and Xhonga, Wolcott & Sognnaes (1972) evaluating the erosion pattern on extracted teeth. These findings should be helpful in further investigation into the aetiology and treatment.Educational, epidemiological and preventive concerns derive from a study establishing the dental erosion frequency on a large population sample (approximately 600 individuals and 1500 teeth). The comparative results for both locations used will provide a more significant basis for future studies of a similar nature.
The determination of free‐way space in edentulous patients: a cephalometric approach
Authors: POTGIETER PIETERJ. , MONTEITH BRIAN D. , KEMP PIETER L. 
Published: June 2007

SummaryThis study was prompted by the hypothesis that the contractile power of the masseter and medial pterygoid muscles influences not only the shape of the gonial angle of the mandible into which these muscles insert, but also that they play a major part in determining the amount of free‐way space present in any individual.Tracings were made from the lateral cephalograms of 130 dentate subjects and the gonial angle measured in each case. Free‐way space was also measured, using a dakometer, and the paired values subjected to statistical analysis. A strong inverse correlation was found to exist, indicating that throughout the sample a decrease (or sharpening) of the gonial angle is accompanied by a predictable increase in the free‐way space. By applying the processes of linear regression to the paired results, a formula was obtained which may be used to predict the best value of one variable for any given value of the other. Thus, in an edentulous case, where the value of the free‐way space measurement is unknown, a method is provided for predicting its best value by the determination of the patient's gonial angle through cephalometric analysis.
Computer graphic representation of mandibular movements in three dimensions: the method
Authors: KNAPP JOHN G. 
Published: June 2007

SummaryA mathematical simulation of the Denar D4A articulator and a simulated complement of graphically represented teeth were programmed in a Prime 4000 minicomputer. The computer program could be manipulated to quantitatively evaluate the theoretical effects of changes in articulator and control factors on the anatomy of selected teeth or tooth groups. The effects of these changes could be assessed graphically and numerically and data could be manipulated statistically.
Alteration in directional specificity of interdental dimension discrimination with the degree of mouth opening
Authors: MORIMOTO T. , HAMADA T. , KAWAMURA Y. 
Published: June 2007

SummaryThe interdental dimension discrimination (IDD) ability was tested at seven different degrees of mouth opening: 40 mm, 30 mm, 20 mm and 10 mm openings for the dentate subjects, and 10 mm opening, intercuspal position (ICP) and the ICP minus 5 mm for the edentulous subjects. The subjects were asked to discriminate between pairs of sticks held alternately between the upper and lower incisors. The IDD ability, evaluated in terms of the 50% difference limen (DL), did not differ significantly between any two of the tests conducted at seven different openings, although the number of misjudgments of the dentate subjects tended to increase with the degree of mouth opening. On the other hand, the directional specificity of the IDD, which is a tendency to overestimate the dimension of the first stick of each pair, developed almost linearly with a decrease in the opening degree. These findings indicate that the behaviour of the receptors concerned varies with the intermaxillary distance. Some edentulous subjects could not perceive the presence of a small test stick at the overclosed position (ICP ‐ 5 mm), but vibration applied to the mandible enabled the subjects to detect the stick at the same opening. These results support the assumption that the muscle spindles of the jaw‐closing muscles are the receptors responsible for the IDD.
Phenomenological model of creep of dental amalgam
Authors: VRIJHOEF M. M. A. , LOURENS F. L. , LEIJDEKKERS‐GOVERS A. F. M. 
Published: June 2007

SummaryEarlier work revealed that creep of a particular dental amalgam can be described by the model F(t)=F0 exp (t/t0)m. Here F(t) is the creep compliance at time t, whereas F0, t0 and m are constants of the model. In the previous study only three alloys were used. It was the aim of this study to investigate the factor alloy more thoroughly. After specimen preparation, the nineteen different amalgams were aged at 37°C for either one day or one week. Then creep was determined at a temperature of 22.5°C and a compressive stress of 117 MN/m2. F
0 turns out to depend upon both the ageing time as well as on the choice of the alloy. As expected, t0 shows up substantial differences between the respective amalgams, whereas the differences between the two ageing are absent or relatively small. The factor alloy significantly influences m. However, the ageing time exerts no significant influence upon m.
Initial physical tests of aluminoborate cements in the context of periodontal dressing development
Authors: WATTS TREVOR L. P. , BERTENSHAW BARRY W. , COMBE EDWARD C. 
Published: June 2007

SummaryA new glass ionomer cement system (aluminoborate) is under consideration for dental applications, including the possibility of a periodontal dressing material. Following the development of pertinent adhesive and rheological tests, two experimental formulations were selected by a simple screening procedure and subjected to appropriate adhesive tests. One formulation proved satisfactory and was subjected to a rheological test in addition. The possible role of aluminoborates as periodontal dressing materials is discussed.
Stomatognathic dysfunction in the western desert of Egypt: an epidemiological survey
Authors: ABDEL‐HAKIM A. M. 
Published: June 2007

SummaryResults of a study of 215 male subjects from Siwa oasis are presented. The Siwian community is representative of the Bedouin communities in the Egyptian western desert. The population belongs to a characteristic ethnic group, living in a primitive way. The most prevalent symptoms were headache (29%), pain in the ear (24%) and clicking joint sounds (19%); 84% of the subjects suffered from tenderness of one or more of the masticatory muscles; 8% of the subjects had painful movements of the mandible.The results extend knowledge of the distribution of jaw dysfunction complaints into hitherto uninvestigated communities.
A comparison of photoelastic and finite element stress analysis in restored tooth structures
Authors: de VREE J. H. P. , PETERS M. C. R. B. , PLASSCHAERT A. J. M. 
Published: June 2007

SummaryTwo methods for determining internal stresses in tooth structures were compared under a specific load condition. The numerical method of the finite element method has a definite number of advantages over the experimental photoelastic method. The numerical results obtained by the first method are in reasonable conformity with those obtained by the latter. In addition the sensitivity of the finite element method towards variation of a number of relevant parameters has been studied.
Salivary flow, saliva, pH and buffering capacity in 70‐year‐old men and women
Authors: ÖSTERBERG T. , LANDAHL S. , HEDEGÅRD B. 
Published: June 2007

SummaryA representative systematic selection of 30% of all 70‐year‐olds (1148 persons) in Göteborg were invited to a population study. The participation rate was 85%. Sixteen per cent of the men and 25% of the women reported dryness in the mouth (sex. diff.P<0.01). There was a significant correlation between the number of drugs consumed by the subjects and subjective dryness (in both sexesP<0.001). Intake of drugs from the groups of anticholionergics, antihistamines, sedatives, hypnotics or phenothiazines respectively seemed to have the highest predicative value for dryness in the mouth (menP<0.05 and womenP<0.01). There was also a positive correlation between subjective dryness and number of definable diseases in both sexes (P<0.01). In a consecutive sample (fifty‐eight men and fifty‐three women) a study of salivary flow, direct pH and buffer effect were performed. The mean value of unstimulated salivary secretion was in men 0.25 and in women 0.18ml/min. Corresponding figures for stimulated secretion was 1.65 and 1.04ml/min (sex. diff.P<0.01).A significantly lower unstimulated secretion was noted in women with subjective dryness (P<0.01).A negative significant correlation were found between dental invalidity, according to Eichner's classification, and stimulated secretion when drug treatment had been considered (menP<0.05 and womenP<0.01). Only weak relations were noted between salivary secretions and drug treatment. Only intake of drugs with diuretic effect were negatively correlated to stimulated secretion (P<0.01). Diseases of the circulatory system were correlated to subjective dryness (P<0.01).
Occlusal adjustment under the control of intra‐oral recording with the aid of the functiograph
Authors: KLEINROK MARIA 
Published: June 2007

SummaryObjective diagnosis of occlusal relationships is possible with the aid of a new instrument called the ‘Functiograph’. It enables recordings of both the free and tooth‐guided mandibular movements to be made intra‐orally on the same tracing plate. A series of twenty cases has been undertaken and a number of selected examples are illustrated.Occlusal equilibration under the control of tooth‐guided movement records enables the estimation of the results of occlusal correction in an objective and methodical way.
Bacteria‐tight sealing of exposed dog pulps
Authors: VAN WEELDEREN M. WIJNBERGEN‐BUIJEN , VAN MULLEM P. J. 
Published: June 2007

SummaryPenetration of bacteria past filling materials can interfere with the vitality of exposed pulps. In the present study, seventy‐three dog's teeth were filled – after exposure – with Cavit‐W and then sealed either with a chemically or a UV polymerizing bonding.After 14 days a failure rate of 28% was demonstrated using the chemically polymerizing Concise and of 4.5% using the UV polymerizing Uvio‐Bond. After 42 days the latter bonding revealed a success rate of 100%.To achieve a bacteria‐tight seal of deep cavities for middle long term animal experimentation, Uvio‐Bond can be used – after etching – to cover the filling material and the surrounding enamel.
The assessment of personality, anxiety and depression in mandibular pain dysfunction subjects
Authors: MOSS ROBERT A. , ADAMS HENRY E. 
Published: June 2007

SummaryThe search for distinct personality characteristics of mandibular pain dysfunction patients has produced confusing and contradictory results. The present study represents an attempt to clarify this area of research by assessing reliable measures of personality (MMPI), anxiety (Speilberger State‐Trait Anxiety Inventory), and depression (Beck Depression Inventory) in ten subjects with a history of facial pain and TMJ sounds. Two control groups, one with TMJ sounds only and other with no history of these symptoms, were matched for sex. The results indicated that the groups did not differ on any of these measures. Discussion focuses on possible explanations for the failure to find any differences in these measures and the future of personality assessment in mandibular pain dysfunction populations.
The transverse strength of acrylic resin strips and of repaired acrylic samples
Authors: GRAJOWER RAFAEL , GOULTSCHIN JOSEF 
Published: June 2007

SummaryA method was developed for measuring the transverse strength of repaired acrylic samples at a single butt joint. The strength was determined for samples prepared from two types of heat polymerizing resins and two types of repair resins. The temperature elevation during curing of the repair resins was determined. Cross‐linking of the resins was evaluated by immersion of samples in solvents. The appearance of the bead microstructure after various treatments was considered to indicate relaxation at the sample surface. Repaired samples of the heat polymerizing resin which exhibited relaxation after immersion in monomer, had a lower strength than samples prepared from the resin for which relaxation was not observed, although both resins were cross‐linked to a similar extent. The application of pressure during curing increased the strength of the samples repaired with the rapid curing, cross‐linked, repair resin. The strength of the samples repaired with the uncross‐linked, slow curing, repair resin was affected by pressure only if the insertion of the repair resin between the sample parts was delayed after mixing. Variations in the powder to liquid ratio of the uncross‐linked repair resin did not affect the sample strength. Wetting of the sample parts with monomer before repair, and variations in the curing temperature did not affect the sample strength for the investigated resin combinations.
A standardized system for evoking reflexes in human jaw elevator muscles
Authors: MURRAY G. M. , KLINEBERG I. J. 
Published: June 2007

SummaryA standardized reproducible system for evoking jaw reflexes following chin tap is described. It represents an improvement over non‐standardized and other standardized forms of instrumentation in that characteristics of the associated jaw displacement and parameters of the evoked jaw jerk reflexes recorded using this system have been shown to be reproducible. The need for standardized instrumentation to evoke jaw reflexes of any kind is emphasized by the influence of graded variations in tap force on the parameters of the evoked jaw jerk reflex response. Thus, higher levels of tap force correlate with an increased jaw jerk duration and amplitude and a decreased latency.
Interdental thickness discrimination in myofascial pain dysfunction subjects
Authors: CLARK G. T. , JACOBSON R. , BEEMSTERBOER P. L. 
Published: June 2007

SummaryInterdental thickness discrimination (ITD) was evaluated on twenty‐eight normal subjects and twenty subjects with myofascial pain dysfunction (MPD). This evaluation was performed before and after a submaximal isometric clenching task sustained to pain tolerance. The results of the study demonstrate a significant difference in ITD ability at several test points between the normal and MPD subjects. The experimental variable of sustained submaximal clenching did not significantly alter the ITD ability of either subject group.
Human discrimination of different bite forces
Authors: WILLIAMS W. N. , LA POINTE L.L. , BLANTON R.S. 
Published: June 2007

SummaryTwenty young adult subjects were selected to determine normal baseline data of dynamic interdental bite force discrimination by use of a specially designed strain gauge instrument. The data may aid in defining the role of the periodontal ligament, temporomandibular joint and muscles of mastication in the regulation of interincisor bite force.
The relationship of lining thickness and thermal insulating efficiency
Authors: JEFFREY I.W.M. 
Published: June 2007

SummaryThe minimum thickness of a lining material that must be inserted into a cavity in order to afford protection to the dental pulp from thermal trauma has never been determined. By taking the diffusivity ratios of the hard dental tissues, amalgam and lining materials and equating them with the situations incurred in the transmission of thermal energy by the unfilled, as against the restored tooth, it becomes possible to produce a simple table from which measurements serving as guidelines for adequate protection can be taken. An experimental method of confirmation of the hypothesis is described.
Guiding sleeve tilt angle in paralleling instruments
Authors: MöLLERSTEN LENNART 
Published: June 2007

SummaryTo investigate the guiding sleeve tilt angle in paralleling instruments, the diameter of guiding sleeves and drill shanks were measured for a number of instrument makes and Spirko type drill makes. Significant diameter differences between makes were found for drills as well as for sleeves. The guiding sleeve tilt angle changed considerably depending on drill—instrument combination. Selection of an unsuitably dimensioned drill could increase the sleeve tilt angle by about four times. A dimensional standardization of guiding shanks and sleeves is thus recommended.
In vitro plaque formation on dental amalgam
Authors: DUMMER P. M. H. , WILLS‐WOOD M. 
Published: June 2007

SummaryA previously described method for the study of in vitro microbial plaque formation on dental materials has been utilized to assess microbial adhesion and growth on five commercially available dental amalgams.Variations in both the amount and viability of the microbial plaques was found between the various types of amalgams.
The influence of stimulus type and stimulus strength on the silent period in human masticatory muscles
Authors: KROON G.W. , NAEIJE M. 
Published: June 2007

SummaryThe silent period in the jaw‐closing muscles of nine healthy subjects was investigated. The stimulus types used were the open–close–clench movement (OCC), the mechanical chin tap and electrical skin stimulation. Irrespective of the jaw‐closing speed for the OCC movements only the unmeasurable and single type silent periods were observed. Increasing the chin tap strength resulted in a decreasing percentage of single type silent periods and an increasing number of depressed, double and merged silent periods. The duration of the short and combined silent period was shorter for the OCC movements than for the chin taps. For the chin taps an increasing stimulus strength resulted in longer silent periods. Only the transition from hard to painful chin tap showed a slight, but significant decrease in short silent period duration. The beginning of the late inhibitory period, which could sometimes be evoked by electrical skin stimulation, coincided with the beginning of the second inhibitory phase of the chin‐tap evoked double silent period. The long silent period as shown by one of the subjects cast doubt on the validity of the relationship between silent period duration and TMJ dysfunction.
Enamel dissolution and fluoride uptake from sugar solutions
Authors: JERUSHALMI I. , MARKITZIU A. , FRIEDMAN M. , GEDALIA I. 
Published: June 2007

SummarySolubility studies and fluoride uptake by enamel powder in xylitol‐buffered solutions versus sucrose‐ and glucose‐buffered solutions were carried out. The studies were done at a pH range of 4–8.The enamel solubility in the xylitol media was similar to the enamel solubility in the other sugar solutions—increasing with a decreasing pH. The solubility of enamel in the buffered sugar solutions was significantly lower as compared to the solubility in the sugar‐free buffered solutions—up to the pH of 6. At the pH values of 7 and 8 the amounts of solubility were similar for the experimental and control solutions.No significant differences were found in the fluoride uptake by the enamel powder from the fluoride‐containing sugar solutions at the pH values of 6 and 7.5 respectively.The results point to the conclusion that the xylitol does not differ from sucrose and glucose in its effect on enamel powder solubility and the uptake of fluoride ions by enamel.
Demonstration of chewing motor disorder by recording peripheral correlates of mastication
Authors: STOHLER C. S. , ASH M. M. 
Published: June 2007

SummaryChewing motor performance was examined in twenty‐one patients. Twelve patients had TMJ dysfunction syndrome, eight had occlusal trauma, and one had CNS impairment. Surface electromyography and three‐dimensional jaw movement was recorded. Discomfort was recorded by the patient during chewing of beefstick. Specific changes in mandibular movement were related to the presence of pain, discomfort and other symptoms of the TMJ dysfunction syndrome.
The fracture toughness (KIC) of amalgam
Authors: LLOYD C. H. , ADAMSON M. 
Published: June 2007

SummaryThe fracture toughness (KIC) has been measured (at 1 week) for a selection of sixteen amalgam products. This included low copper (i.e. Cu<6%) and high copper (both single component and admixed) products in milled and spherical powder forms. The results have shown that the fracture toughness decreases progressively as the copper content increases. The admixed high copper products possess superior fracture toughness to those containing a single component powder. These results have been attributed to differences in the microstructures produced by changes in composition and form in which the copper addition is made.
Association between tooth loss and TMJ dysfunction
Authors: KIRVESKARI P. , ALANEN P. 
Published: June 2007

SummaryAn analysis of the distribution of tooth losses in 521 subjects having lost one to fourteen teeth, disclosed a statistically significant association between the loss of maxillary first premolar and the presence of TMJ dysfunction. The association was evident on both sides. Maxillary first premolars have earlier been shown to contact prematurely on hinge closure more often than the other teeth. The loss of other teeth seemed independent of the functional state of the stomatognathic system. It is suggested that TMJ dysfunction may predispose to the loss of the maxillary first premolar by direct trauma to the tooth and/or by speeding up periodontitis.