bluuebunny/crossref_metadata_2025_split huggingface dataset:
Tooth wear measurements using a reflex microscope
Authors: ADAMS L. P. , WILDING R. J. C. 
Published: June 2007

SummaryThe resistance to wear of composite resins is an important feature of their suitability for use as posterior restorative materials. The in vivo clinical evaluation of new materials requires an accurate and reliable method of assessing tooth wear. The purpose of this study was too investigate the possibility of using a new stereometric measuring instrument for this purpose. Tooth wear was experimentally produced on a lead cast. The volume and average depth lost was measured using a reflex microscope. A gravimetric method of wear measurement was used as a control. When the results of both methods were compared it was found that the mean difference in depth of wear measured between the two methods was 10 μm. The reflex microscope appears to be ideally suited to making objective comparisons between the wear characteristics of composite resins.
Finite element analysis of a mandibular model
Authors: FARAH J. W. , CRAIG R. G. , MEROUEH K. A. 
Published: June 2007

SummaryA two‐dimensional finite element model of a mandibular quadrant was used to examine the stresses and displacements resulting from a 100 N load placed as follows: (i) distributed on the second molar, (ii) concentrated at 30° to the vertical on the second molar, and (iii) distributed on the second premolar and second molar. Each tooth was supported by periodontal ligaments, cortical and cancellous bone. The modulus and Poisson's ratios for each material were selected from accepted values. The principal stresses were determined throughout the model, with special emphasis being placed for elements in the immediate vicinity of the teeth mentioned above.It was found that for the case where the load was uniformly distributed on the second molar the stresses σmain were mostly compressive (–) in nature while σmax were mostly tensile (+). In the case where the load was concentrated and at 30° to the vertical, the magnitude of the stresses were three to five times greater and the pattern less uniform than those resulting from the distributed load.The concentrated load at 30° to the vertical resulted in higher bending stresses than the distributed load and hence higher σmax stresses.
Physical properties of addition silicones as a function of composition
Authors: WILLIAMS J. R. , CRAIG R. G. 
Published: June 2007

SummaryThe effects of molecular weight of the base silicone, filler and copolymer concentrations on compression set, strain, creep and dynamic elastic modulus were determined. The molecular weight of the base silicone had the least effect on these properties although low molecular weights showed better properties. Chain extenders were detrimental to physical properties of creep, compression set and dynamic elastic modulus. Increased copolymer concentrations decreased compression set, strain and creep and increased the dynamic elastic modulus. The useful copolymer/base functional group ratio was from 1:1 to 3:1. Filler affected properties to a lesser extent than copolymer ratio. Compression set, strain, and creep decreased and the dynamic elastic modulus increased with increasing filler with the properties being directly proportional to the weight fraction. All properties were interrelated with In strain linearly related to In compression set, creep proportional to set, and the dynamic elastic modulus was inversely correlated with strain and creep.
History factors associated with symptoms of temporomandibular disorders
Authors: PULLINGER A. G. , MONTEIRO A. A. 
Published: June 2007

SummaryDifferences in prevalence of head or neck trauma, orthodontic treatment and molar oral surgery procedures reported by individuals were compared among patients with temporomandibular disorders (TMD) and with two comparison groups (a sample of asymptomatic individuals, and a sample with mild or early signs). Association to specific TMD symptoms was tested amongst the comparison groups.Trauma was the most significant factor characterizing TMD patients. History of trauma was also more common among those otherwise normal but symptomatic individuals in the non‐patient comparison group. Specific TMD symptoms were significantly associated with history of trauma in the comparison group. Significantly more women TMD patients had a history of orthodontic and molar oral surgery treatment than the asymptomatic comparison group. History of orthodontics was also associated with the symptomatic sample of the comparison group in women, but it was not significantly related to any specific TMD symptoms. Symptomatic members of the comparison group could not be differentiated based upon history of molar oral surgery.Certain risk factors may have been delineated, but causal relationship of treatment requires study of co‐existing and predisposing behavioural and structural factors.
Relationship of first primary palatine rugae to the maxillary canines in man
Authors: GROVE H. F. , CHRISTENSEN L. V. 
Published: June 2007

SummaryFifty dentate maxillary casts, obtained from thirty‐four males and sixteen females, were mounted in the three‐dimensional co‐ordinate system of a contour meter. A transverse line of reference (x‐axis) was drawn through the distal contact points of the maxillary canines, at a right angle to the y‐axis which passed through the contact points of the maxillary central incisors. Relative to the canine‐to‐canine baseline, the locations of the lateral borders of the right and left first primary rugae were determined. The rugae were distributed on both the anterior and posterior sides of the baseline, and the anterior and posterior distances from the baseline were on the average about 1 mm. The age of the subjects, ranging from 12 to 52 years, appeared to be unrelated to the frequencies of anteriorly and posteriorly positioned rugae. Right and left first primary rugae, located on the anterior side of the baseline, showed a minute asymmetry in their topography. By contrast, there was topographical symmetry when the rugae were located on the posterior side of the baseline.
Colour effect of denture base on denture tooth materials
Authors: MILLSTEIN P. L. , HARLAN J. , NATHANSON D. 
Published: June 2007

SummaryA study using a HunterLab colorimeter was conducted to determine the colour effect of denture base materials on denture tooth acrylics.The results show that denture base materials create a measurable change in the chroma of denture tooth acrylics and suggest that optimal shade selection of teeth should include a determination of the background effects of denture base materials.
Electromyographic studies of craniomandibular disorders: a review of the literature
Authors: DAHLSTRÖM L. 
Published: June 2007

SummaryCraniomandibular disorders have been investigated from many points of view, structurally and functionally. To evaluate the behaviour of the masticatory muscles, electromyography (EMG) has been widely used and the studies have emanated from many different paradigms. The purpose of this paper is to review articles in which EMG has been used to study symptomatic subjects.Findings from sleep studies and basic laboratory studies seem to support the hypothesis of a correlation between masticatory muscle hyperactivity and symptoms. Experimentally induced stress studies consistently show an increased activity in symptomatic subjects.Investigations of motor pauses, the often lengthened silent period, are summarized and discussed. Several different treatment strategies, particularly splints and biofeedback, have been evaluated using EMG, indicating a normalization, but controlled outcome studies are sparse. The use of EMG has thus substantially increased our knowledge of dysfunction of the masticatory system.
Real‐time signal acquisition and analysis for clinical dental electromyography using a microcomputer‐based system
Authors: YUEN S. W. H. , MA R. Y. P. , CHUNG Y. C. , HWANG J. C. C. 
Published: June 2007

SummaryThe Electromyographic (EMG) Signal Acquisition and Analysis System is an integrated hardware and software system that digitizes multichannels of amplified EMG signals and stores them in user defined disc files before analysis. The software runs on all IBM PC and its compatibles with the appropriate analogue‐to‐digital (A/D) conversion board. Both time and frequency domain analyses can be computed on‐line. This system provides a low cost method of digitizing and analysing EMG signals on real‐time for clinical dental electromyography.
Oral pathology and prostheses—are they related? Investigations in an elderly population
Authors: HOAD‐REDDICK G. 
Published: June 2007

SummaryA survey of 233 elderly subjects living in the district served by the Halton Health Authority (Cheshire, England) investigated the relationship between the age of dentures, their need for replacement and the presence of any oral pathological lesions. The retention, stability, occlusion and cleanliness of the dentures were all found to be worse in the older appliances; perceived need for denture replacement was found to increase from 40% in 5‐year‐old dentures to 84% in dentures over 31 years old. While 41% of the sample had an oral pathological lesion, no significant relationship was found between denture age and pathology or place of residence. People resident in the community with no assistance had the highest incidence of oral pathology and those living in long‐stay hospitals the least. The absence of a relationship between denture age and oral pathology is considered to be a powerful indicator of the need for regular oral examination of the edentulous population.
The effects of cusp and jaw morphology on the forces on teeth and the temporomandibular joint
Authors: KATONA T. R. 
Published: June 2007

SummaryBasic principles of engineering mechanics are used to solve for force vectors in the masticatory system. It was found that incisor guidance/cusp angulation, crown heights and the anterior‐posterior location of contact can significantly affect the magnitudes and/or directions of forces acting on contacting teeth and the temporomandibular joint. The results provide insight into the function of the jaws and the diagnosis and treatment of occlusion‐related trauma.
Preliminary studies of some masticatory characteristics of bruxism
Authors: FAULKNER K. D. B. 
Published: June 2007

SummaryThe masticatory cycles of bruxist subjects were studied using a closed‐circuit television movement detector. These cycles were compared with those of non‐bruxist subjects.Early results indicate a shorter stationary period between masticatory cycles in all components of movement in bruxist subjects than in non‐bruxist subjects. Also, in some bruxists, the envelopes of motion showed quite irregularly shaped patterns, with sudden changes in direction, while others showed a loss of the classical teardrop pattern.
Spectral analysis of the masseter and anterior temporalis: an assessment of reliability for use in the clinical situation
Authors: BARKER G. R. , WASTELL D. G. , DUXBURY A. J. 
Published: June 2007

SummaryThe electromyogram (EMG) of contracting muscles can be analysed in the frequency domain by spectral analysis. However, there is a need to establish the reproducibility of spectral parameters such as mean power frequency (MPF) This study examined the variation of MPF (masseter and anterior temporalis) between and within recording sessions.The MPF was found to be significantly reliable for both muscles, but considerable within‐subject variation was found despite comprehensive measures to standardize recording methods and conditions. It is concluded that MPF may have clinical application in the diagnosis and treatment of patients with facial pain arising from muscle dysfunctions, but caution should be exercised in interpreting small changes in frequency, given the inherent variability of MPF.
Dietary pattern, energy and nutrient intake in patients with oro‐facial discomfort complaints
Authors: YONTCHEV E. , SANDSTROM B. , CARLSSON G. E. 
Published: June 2007

In ninety‐six patients with oro‐facial and general complaints, which the patients assumed were caused by galvanic currents and/or metallic restorations, the recording and analysis of dietary pattern, energy and nutrient intake were performed. The records, in household measures, of the intake of food and beverages during 7 consecutive days according to a written instruction were collected. Sixty‐eight out of the ninety‐six records were sufficiently complete for calculation of nutrient intake. The remaining twenty‐eight could only be used partially in the analyses.Most of the patients had a varied food intake of all the food groups during the 7‐day period. The range was wide, however, and a few patients had relatively low intake of essential nutrients. It was not possible to find any correlation between oro‐facial discomfort complaints and intake of any single nutrient that could indicate a cause‐effect relationship. No correlation between diet pattern, energy and essential nutrients, and the measured electrode potentials of the fillings and constructions could be proved. Nor could the hypothesis that beverage intake might influence the electrode potentials and increase or aggravate the oro‐facial complaints be verified.
The mandibular condyles in the submentovertex projection—their morphology and topographical relationship to the foramina spinosa
Authors: KRENKEL C. , GRUNERT I. 
Published: June 2007

On conventional radiographs, the morphology and position of the condyles in an axial view are best seen in the submentovertex projection. The foramina spinosa, which are used by the middle meningeal arteries as passages and are clearly outlined in this view, serve as landmarks for a co‐ordinate system that permits precise measurements of various angles and distances.One hundred and twenty‐six submentovertex views were used for measuring the condyles. Results presented as means and standard deviations suggest condylar variables to be related to the function of the stomatognathic system. Practical applications include surgical, orthodontic or prosthetic manipulations of the mandible resulting in transverse or sagittal displacement of the condyles.
Myodynamic and conventional construction of complete dentures: a comparative study of comfort and function
Authors: BARRENÄS L. , ÖDMAN P. 
Published: June 2007

SummaryFunction and comfort during wearing of myodynamically and conventionally constructed dentures were evaluated in 30 patients. All patients were fitted with one set of myodynamic and one set of conventional dentures. The neutral zone was recorded with a Xantopren® blue impression. Twenty‐three of the patients preferred the myodynamic dentures, two preferred the conventional dentures, two experienced no difference and three patients used a combination of the conventional and the myodynamic sets. There were also less post‐insertion problems with the myodynamic dentures compared to the conventional ones.
Human bite force discrimination using specific maxillary and mandibular teeth
Authors: COFFEY J. P. , WILLIAMS W. N. , TURNER G. E. , MAHAN P. E. , LAPOINTE L. L. , CORNELL C. E. 
Published: June 2007

SummaryThe purpose of this study was to determine whether performance differences existed in subjects'self‐generated bite force discrimination ability using maxillary and mandibular central incisors, canines, premolars and first molars. Two separate studies were conducted: (i) to assess whether performance differences existed in subjects'bite force discrimination ability using central incisors and premolars; (ii) to compare subjects'performance on bite force discrimination using central incisors, canines and first molars. Assessment of bite force was measured using a specially designed strain gauge scale allowing subjects to visually monitor when their biting force equalled a preset resistance. Resistance forces of 500, 1000 and 3000 g were selected as standards. Subjects were presented with a series of paired resistance settings, one at a time, the first of each pair being the standard and the second being the comparator setting of a predetermined amount. This paired‐comparisons procedure was continued until the subjects'difference limen (DL) value (the threshold of discrimination between two forces) could be established. The first study revealed no significant (P>0.05) overall difference in subjects'bite force discrimination ability relative to specific teeth. In contrast, in the second study a significant difference (P<0.05) was identified in subjects'performance relative to specific teeth; subjects performed better using central incisors compared to first molars. In both studies, subjects' performance was significantly better (P<0.05) using the 500g standard compared to the 3000 g standard in the first study, and compared to the 1000g standard in the second study. No significant differences (P<0.05) were observed between the performance of males and females in either study.
Diagnosis of caries and treatment decisions in approximal surfaces of posterior teeth in vitro
Authors: NOAR S.J. , SMITH B.G.N. 
Published: June 2007

SummaryThe diagnosis of caries and treatment planning decisions have been reported to vary widely between individual dentists. However, opinions differ as to whether, in general, this results in too much or too little treatment.Eighty‐six dentists, mainly attending post‐graduate meetings, participated in this study. They were asked to make diagnostic and treatment planning decisions on a selection of extracted teeth set in realistic contact with each other. These decisions were compared with the appearance of the proximal surfaces before setting the teeth in contact, and the histological appearance of the teeth that were sectioned after the dentists had made their decisions.Opinions as to whether caries was present and whether it required treatment showed a wide distribution. However, had the decisions been acted upon, between 1‐6% of the sound surfaces would have been filled, but 20–68% of teeth with clearly cavitated surfaces or histological evidence of dentine involvement would not have been filled.
Clinical evaluation of two posterior composite resins: two‐year results
Authors: STANGEL I. , BAROLET R.Y. 
Published: June 2007

SummaryTwo composite resins were evaluated for clinical acceptability as restorative materials in Class I and II cavities over a 2‐year period. In addition, dispersed phase alloy was evaluated for comparison. All restorations were assessed for anatomical form, marginal integrity and marginal leakage using modified United States Public Health Service (USPHS) criteria. At the 2‐year recall, 96% of the composites and 100% of the amalgams were rated ‘alpha’ or ‘bravo’, using the parameters of assessment defined in this study. However, a significant number of shifts from the baseline, within the level of acceptability, had occurred. The two composites showed the greatest number of shifts for anatomical form and marginal leakage, while there were no differences between the composites and the amalgam for shifts in marginal integrity. Although a very high level of acceptability was determined for all of the materials, the frequency of rating change within categories for the composites was a cause of concern with regard to their long‐term clinical use.
An evaluation of a rapid setting glass ionomer cement used by general dental practitioners to restore deciduous teeth
Authors: KNIBBS P. J. , PLANT C. G. 
Published: June 2007

SummaryTwenty‐one general dental practitioners evaluated the clinical handling properties and performance of a newly formulated glass ionomer cement of the powder/water type. One hundred and eighteen restorations were placed. Sixty‐nine restorations were reviewed, on average, after 6 months by 17 practitioners who completed the trial. This formulation set rapidly. Approximately 90% of the restorations that were reviewed performed well over the period of assessment. The results of the trial were compared with those of trials on earlier glass ionomer cements used to restore deciduous teeth. The main advantage of the new formulation was the improvement in handling properties.
Finishing composite restorative materials
Authors: WILSON F. , HEATH J. R. , WATTS D. C. 
Published: June 2007

SummaryA clinically realistic in vitro study was performed to determine the best method for smoothing trimmed surfaces of seven composite restorative materials. Soflex discs produced the smoothest surface, and little advantage appeared to be gained by prior smoothing of the surface with stones or points. A polishing paste, even when used with intermediate finishing agents, produced a rougher surface than that left by the discs.
Oral comfort in shortened dental arches*
Authors: WITTER D.J. , VAN ELTEREN P. , KÄYSER A.F. , VAN ROSSUM G.M.J.M. 
Published: June 2007

SummaryIn this study, the oral comfort was compared between subjects with shortened dental arches (SDA, n= 74), subjects with SDA and free‐end removable partial dentures (SDA + RPD, n= 25) and subjects with complete dental arches (CDA, n= 72).Oral comfort was measured by (i) absence of pain or distress; (ii) chewing ability; (iii) appreciation of the appearance of the dentition. Additionally, the history of free‐end RPD over a period of nearly 7 years was taken into consideration.On the whole, the results did not reveal any significant differences between the three groups with respect to pain or distress. Only 8% of the subjects with SDA reported impairment of chewing ability, and 11% had aesthetic complaints, due to missing posterior teeth in the upper jaw. Of the subjects with SDA * RPD, 20% had complaints about the RPD. In addition, the repeated necessity for repair or replacement of free‐end RPD and the fact that some subjects (20%) stopped wearing the RPD during the observation period, confirm the poor performance of this dental provision. It is concluded that the oral comfort of subjects with SDA in this study is compromised to a small extent but remains on an acceptable level. Free‐end RPDs do not appear to help oral comfort in these cases.
Further studies of mandibular movement at initial tooth contact
Authors: FAULKNER K.D.B. 
Published: June 2007

SummaryBy measurement of movement of the mandible immediately after tooth contact during tooth tapping tasks, it has been shown that patterns of direction are less regular in bruxist subjects than in non‐bruxist individuals. The qualitative differences in these patterns are more apparent than the quantitative ones in both cessation and commencement of movement.
Other dental treatment needs in patients who requested removable partial dentures
Authors: ISA Z. , YUSOF Z. 
Published: June 2007

SummaryThe aims of this study were to determine the dental and periodontal status and the associated treatment needs, other than that for prosthetic care, in patients who requested removable partial dentures. Forty‐six patients who had never worn removable partial dentures before were examined for plaque index, tooth status, gingival index, loss of periodontal attachment and tooth mobility. Prior to prosthetic treatment, 15% of the teeth needed conservative treatment and 1% needed extractions. From the periodontal point of view, 65% of the teeth needed some form of related therapy, and 2% of the teeth were at risk of extraction due to advanced mobility.