bluuebunny/crossref_metadata_2025_split huggingface dataset:
Orofacial functions in patients with congenital and acquired maxillary defects: a fluoroscopic study
Authors: YONTCHEV E. , KARLSSON S. , LITH A. , ALMQVIST S.Å. , LINDBLAD P. , ENGSTRÖM B. 
Published: June 2007

SummaryBy means of videofluoroscopic recordings, chewing, swallowing and speech were monitored in nine patients with congenital and acquired maxillary defects. All of them were rehabilitated with a maxillary obturator prosthesis. The defective region was seldom used for chewing. No leakage between the obturator and surrounding tissue was observed, either for solids or for liquids. All of the prosthetic reconstructions were surprisingly stable during function. In the phonetic analysis, speech production was judged to be restored almost to normal. Videofluoroscopy may be valuable as a complement to other functional diagnostic procedures, and for the evaluation and improvement of rehabilitation with an obturator prosthesis.
In‐vitro study to compare the efficacy of N‐monochloro‐D,L‐2‐aminobutyrate (NMAB, GK‐101E) and water in caries removal
Authors: BARWART O. , MOSCHEN I. , GRABER A. , PFALLER K. 
Published: June 2007

SummaryThe present in‐vitro study was designed to investigate the chemical efficacy of N‐monochloro‐D,L,‐2‐aminobutyrate (NMAB, GK 101E) in removing carious material under clinically relevant conditions, using objective methods of measurement. Assuming that the chemical effectiveness of water in caries removal is minimal, a comparison of the efficacy of GK‐101E with that of water was made. The force required to achieve complete caries removal from symmetrically separated carious lesions was determined with the CaridexTM system, modified by a force gauge. One lesion half was treated with GK‐101E, while the corresponding half was treated with water. Thus a difference in the chemical potential of the fluids in softening carious material should lead to a difference in the force required to remove equal quantities of caries. Statistical analysis of the findings of the present study revealed no significant difference between GK‐101E and water, with regard to both the force and the number of excavation strokes and the time needed for caries removal. It is concluded that, under the given test conditions, the removal of carious dentine is not significantly enhanced by the chemical action of GK‐101E.
Stresses generated by luting resins during cementation of composite and ceramic inlays
Authors: REES J.S. , JACOBSEN P.H. 
Published: June 2007

SummaryThe present study used the finite element method to model the stresses generated by a composite luting cement around a class I composite restoration and a ceramic inlay. In many cases maximum tensile stresses of > 20MPa were found, and failure of the restoration‐dentine and restoration‐glass ionomer interfaces was predicted.
Longitudinal study on torque transmitted from a denture base to abutment tooth of a distal extension removable partial denture with circumferential clasps
Authors: OGATA K. , ISHII A. , NAGARE I. 
Published: June 2007

SummaryNot only forces but also torque exerted on abutment teeth are important factors for planning the construction of distal extension removable partial dentures. The purpose of this study was to make longitudinal analysis of torque transmitted from denture base to a direct abutment tooth of these dentures with circumferential clasps.The results are summarized as follows:(i) Vertical Max. MT (maximal mean value of torque) was decreased and became constant after one or one and half months of the insertion of new dentures.(ii) Lateral Max. MT in one subject was changed from the lingual direction to the buccal direction while in another subject it was constant.(iii) In the vertical direction, there were no remarkable differences of Max. MT and Ave. T (average value of torque) between subjects. Max. MT was 5–10 × 10−3 kgm−1 in the downward. Ave. T was 2–3 × 10−3kgm ss−1 in the downward and 0.3 × 10−3kgm ss−1 in the upward.(iv) In the lateral direction, there were considerable differences of Max. MT and Ave. T between subjects. Max. MT was less than 20 × 10−3kgm. Ave. MT was 2–8 × 10−3 kgm ss−1.
Masticatory function in hemimandibulectomy patients
Authors: MARUNICK M.T. , MATHES B.E. , KLEIN B.B. 
Published: June 2007

SummarySurgical resection of a segment or loss of continuity of the mandible can adversely affect most of the structures essential for mastication. Five subjects who had hemimandibular resections for cure of squamous cell carcinoma were studied. Masticatory function tests were conducted pre‐ and post‐surgery and post‐prosthetic rehabilitation. A 0.5‐g Frito® corn chip served as the test food, and a sieve analysis was used to evaluate swallowing threshold and masticatory performance. Ten controls were studied in order to determine corresponding normative scores. Post‐surgery results indicate that the extent of mandibular resection and loss of continuity tend to decrease masticatory function. The time required to perform the mastication test, and the number of strokes required to achieve swallowing threshold were increased. Prosthetic rehabilitation did improve masticatory function in some patients. Loss of mandibular continuity may not be an absolute predictor of decreased masticatory function.
A new guide for positioning of maxillary posterior denture teeth
Authors: EL‐GHERIANI A.S. 
Published: June 2007

SummaryThere is no definitive method for the arrangement of artificial teeth in complete denture construction. A new method is introduced whereby the maxillary posterior teeth have been set in approximate positions mediolaterally similar to their natural predecessors. The procedure is based on a constant relationship derived from the natural dentition. Its clinical application proved to be suitable for the arrangement of artificial teeth for complete dentures with minimal errors.
Filler particle size and composite resin classification systems
Authors: LANG B.R. , JAARDA M. , WANG R.‐F. 
Published: June 2007

SummaryThe currently used composite resin classification systems need review if they are to continue to serve as descriptives and quantitative parameters denoting the filler particle content of these materials. Examination of the particles in 12 composite resins using a technique of washing the filler particles from the matrix of the composite resin was presented as yet another method of grouping composites according to filler particle content. Light microscopic examination of the filler particles that remained provided a separation of the 12 materials into four easily distinguished groups based on filler particle sizes. The wear of the 12 composite resins determined in a previous study was examined in relation to the classification of the materials by the currently available systems. The wear values were also examined using the groupings of the materials according to their filler particle sizes as determined by separating the particles from the matrix by the washing technique. Grouping composites on the basis of the filler particle sizes found after washing was easily correlated with wear and supported the suggestion that composites with smaller filler particles wear less.
An in vitro study of the influence of X‐ray beam angulation on the adiographic images of the amelocemental junction and simulated alveolar crest
Authors: JENKINS S.M. , DUMMER P.M.H. , ADDY M. 
Published: June 2007

SummaryThe aim of this in vitro study was to determine the effect of X‐ray beam angulation on the radiographic images and relative positions of the amelocemental junction and alveolar crest. Using an artificial model to represent the tooth/bone relationship, radiographs were taken of a total of 15 extracted premolar teeth which had been divided into three distinct groups on the basis of the contour (configuration) of their approximal amelocemental junction. Radiographs of the tooth/bone units were taken at baseline and with a range of horizontal and vertical X‐ray beam angulations from 5° to 20°. Analysis of the radiographs revealed that when using the ideal horizontal angulation the radiographic image of the amelocemental junction was dependent upon its contour and was not always represented by its mid‐point bucco‐lingually. Changing the horizontal angulation of the X‐ray beam altered substantially that part of the junction visible on the film regardless of contour. Variation in the vertical angulation of the X‐ray beam had little influence on the distance between the radiographic images of the amelocemental junction and a point representative of the approximal crest of the alveolar bone. It is concluded that the contour of the approximal amelocemental junction has an influence on its radiographic appearance and that films taken with an inappropriate horizontal angulation never provide an image of its mid‐point bucco‐lingually.
Bite‐force endurance in patients with temporomandibular joint osteoarthrosis and internal derangement
Authors: STEGENGA B. , BROEKHUIJSEN M.L. , DE BONT L.G.M. , VAN WILLIGEN J.D. 
Published: June 2007

SummaryThe aim of this study was to investigate the potential clinical relevance of testing bite force endurance in patients with articular temporomandibular disorders. The endurance of a 50 N bite force was measured in 51 patients with painful temporomandibular joint disorders. The results were compared to those of a control group of 20 subjects. The force exerted was sustained until this taks could not be continued because of intolerable pain or fatigue. The endurance test was repeated following therapy.Testing bite force endurance could be reliably carried out (paired t‐test not significant, procluct‐momel11 correlation coefficient 0.87). The mean endurance time in the patient group was significantly different from that of the control group (t = 7.43, df = 69, P < 0.01). The 95% confidence intervals for patients and controls did not show any overlap. No difference in endurance time between diagnostic subgroups could be cletectcd (F = 1.30, df = 4,46, P < 0.28). Following treatment, all patients showed a significant increase of enclurancc time (t = 8.09, df = 50, p < (1.01) and reported a decrease in post‐test pain. The mean difference between pre‐ and post‐treatment endurance was 60s. Subjecls of the control group stopped the biting effort predominantly because of muscle fatigue. By contrast, the main reason of the patients to cease the effort was TMJ pain.The results of this study indicate that the discriminatory power of the test is sufficient to justify ils utility as a complementary tool in assessing the functional capacity of the masticatory system.
Maxillofacial prosthetics‐an international perspective of the British status quo*
Authors: WOLFAARDT J.F. 
Published: June 2007

SummaryMaxillofacial prosthetics is a recognized subspecialty of prosthodontics. In considering the international status of maxillofacial prosthetics it is found that this unique and superspecialized discipline has a varied implementation both in terms of educational structures employed and clinical services provided. There is a dirth of available literature on education in maxillofacial prosthetics. The available literature is reviewed and the conclusion drawn is that very little undergraduate or postgraduate curriculum time is devoted to maxillofacial prosthetics in Prosthodontic curricula. This, it is felt, adds to the ignorance of this important aspect of dentistry. Educational guidelines are reviewed and from this it is evident that the North American model of Prosthodontic education and training differs greatly from the British one. This dichotomy appears to have impacted on Prosthodontic training in other countries. Maxillofacial prosthetics enjoys special status in the United States but does not seem to be an important aspect of training in the British model. Indeed there is little evidence that maxillofacial prosthetics is an important focus of the British Consultant in Restorative Dentistry. Given the availability of the superb skills of the British trained maxillofacial prosthetic technicians and the hospital based restorative services, it is remarkable that the Restorative Consultants have not exercised their natural opportunity to lead internationally in both clinical and research areas, in this important discipline of dentistry. This must undoubtedly pose a challenge for the British dental profession as a whole in the future.
Preliminary observations on oral blood flow
Authors: CHRISTENSEN L.V. , DONEGAN S.J. 
Published: June 2007

SummaryUsing laser Doppler flowmetry (LDF), the blood microcirculation of the masseter muscle was studied in one healthy male subject performing clenching and grinding of the teeth. LDF suggested that blood flow was increased during clenching, and that it did not change appreciably during grinding. In one female patient (acute pain from myofibrositic lesion in masseter muscle), LDF suggested that How within the lesion was increased during rest (postural position). In three healthy adults, subjected to simulated traumatic occlusion of the incisors, LDF suggested an absence of consistent changes in pulpal blood flow.
Thermoanalytical characterization of visible light cure dental composites
Authors: VAIDYANATHAN J. , VAIDYANATHAN T.K. , WANG Y. , VISWANADHAN T. 
Published: June 2007

SummarySelected commercial and experimental composites and resin systems have been evaluated by thermal analysis techniques of Differential Scanning Calorimetry, Thermogravimetric Analysis and Thermomechanical Analysis. Important thermal data such as heat of cure, coefficient of thermal expansion, dimensional changes over selected temperature ranges, filler weight percent, onset temperature of decomposition, temperature of peak decomposition rate, temperature of the end of decomposition, etc. have been determined. Heat of cure, thermal expansion coefficient and dimensional changes appear to follow an inverse linear regression fit with filler fraction in the composite. Thermal expansion changes and exothermic reactions with temperature indicate secondary cure during postcure heating. The thermally‐induced decomposition occurs in multiple stages indicating presence of different structural species in the resin matrix.
The effects of dentine bonding agents on marginal leakage of composite restorations – long‐term studies
Authors: GRIEVE A.R. , SAUNDERS W.P. , ALANI A.H. 
Published: June 2007

SummaryThe aim of this study was to compare the effects upon marginal leakage of a number of dentine bonding agents when used with a posterior composite resin, Occlusin, after storage for periods of up to 2 years. The bonding agents used were Gluma, Scotchbond, Topaz and an experimental material. The results were compared with a glass ionomer, Chemfil II. Class V cavities with or without a bevelled cavo‐surface margin were prepared in the buccal surfaces of extracted premolar teeth. Following restoration, the teeth were stored for periods of up to 2 years and then thermally cycled. Marginal leakage was subsequently demonstrated using a radioactive isotope containing 45Ca, and an auto‐radiographic technique. Image analysis was used to determine the total amount of linear leakage for each specimen. The results showed that some leakage occurred for all materials at each time interval. The bevelled design of cavity allowed significantly less leakage than the unbevelled cavity. Overall, there was little difference between the various dentine bonding agents. The glass ionomer restorations showed significantly less leakage than the composite resin and dentine bonding agent combinations in unbevelled cavities.
The recording and analysis of EMG and jaw tracking. II. reproducibility of jaw tracking
Authors: HOWELL P.G.T. , ELLIS S. , JOHNSON C.W.L. , WATSON I.B. , KLINEBERG I. 
Published: June 2007

SummaryIn 10 male and 10 female adults jaw movements and muscle activity were monitored during chewing. Subjects had a Class I occlusion and fluent unrestricted jaw movements; none exhibited signs or symptoms of craniomandibular disorders. Recordings were made on two occasions separated by 2 weeks. Within each recording session the subjects carried out a number of tasks under direction, including eating nuts and gum. The jaw movements were monitored with a Sirognathograph® which had been interfaced to a computer for data logging and analysis.A computer program identified each chewing stroke and after scrutiny a data base was constructed of measurements from a subset of 4447 suitable strokes. Mean values of 10 parameters selected to describe jaw movements during chewing were entered into an anova. This indicated that the major contribution to variance was due to the subject from whom the data was recorded. This intersubject variability is well known, but can its separation from the other contributions to the variation within the data be assessed? To provide an estimate of the spread of data the variance for each parameter was calculated, transformed and these values entered into an analysis of variance.All subject differed significantly in their chewing movements from one another. But 15 of the 20 subjects showed a greater degree of consistency than the other five: they exhibited good inter‐ and intra‐recording reproducibility. The food being eaten made a major contribution to the variability. The timing of the chewing strokes was also more consistent than the dimensions of the chewing envelope.
Nature and frequency of dental wear facets in an Australian Aboriginal population
Authors: KAIDONIS J.A. , RICHARDS L.C. , TOWNSEND G.C. 
Published: June 2007

The nature and frequency of dental wear facets were studied in a sample of 18‐year‐old Aborigines, 28 males and 31 females, living at Yuendumu in the Northern Territory of Australia. Facet frequencies were scored indirectly using dental models for all permanent teeth, except third molars, and evidence of non‐masticatory tooth grinding in eccentric jaw positions was also recorded. The interplay between attrition and abrasion in an individual over time was assessed by examining facet appearance on serial dental models obtained at approximately yearly intervals from 7 to 25 years of age.Facetting was found to be a very common feature of the Aboriginal dentitions, with frequencies ranging from around 65% for pre‐molars to about 90% for molars. Evidence of extreme mandibular movement was noted in 93% of males and 100% of females. The longitudinal observations indicated that wear facet definition varied over time, apparently due to episodes of tooth grinding superimposed on continually‐acting abrasive influences.These results show that facetting on teeth associated with extreme mandibular positions and, by inference, the related behaviour of tooth grinding or bruxism are very common features in dentitions of Australian Aboriginals living an essentially non‐industrial way of life.
Taurodontism and length of teeth in patients with oligodontia
Authors: SCHALK‐VAN DER WEIDE Y. , STEEN W.H.A. , BOSMAN F. 
Published: June 2007

Taurodontism and a reduced tooth length are reported to occur in patients with oligodontia. The aim of this study was to evaluate the occurrence of these factors in Dutch patients with oligodontia.Panoramic radiographs of 117 patients with oligodontia and 91 controls were collected. Taurodontism of the mandibular first molars was recorded and the length of cuspids, bicuspids and first molars of the mandible were measured. In patients with oligodontia 28.9% showed taurodontism of one or two mandibular first molars. The prevalence of taurodontism in normal Dutch subjects was 9.9%. No significant differences were found between the two sexes in both groups. Neither was there a significant difference in the unilateral and bilateral occurrence of taurodontism. The present findings supported the hypothesis that taurodontism may be the result of an ectodermal defect and a manifestation of developmental instability in patients with oligodontia. The length of mandibular cuspids and first molars in females were significantly reduced. In males only the lower right first molar was significantly reduced. The reduced length of the teeth may also be the result of a defect in ectodermal cells. Both taurodontism and a reduced length are of importance considering dental therapy.
Radiopacity of 12 visible‐light‐cured dental composite resins
Authors: TOYOOKA H. , TAIRA M. , WAKASA K. , YAMAKI M. , FUJITA M. , WADA T. 
Published: June 2007

SummaryThe radiopacity of 12 VL‐cured composite resins was determined with reference to an aluminum step‐wedge. Two anterior composites were radiolucent while two anterior and one anterior/posterior composites exhibited the radiopacity equal to, or slightly greater than, that of human enamel. Three posterior and one inlay composites possessed the radiopacity equivalent to, or in tiny excess of, that of human enamel. Three posterior composites had the radiopacity, fairly exceeding that of human enamel. Chemical analyses of the filler particles were carried out with SEM/EDX. It became evident that radiopaque fillers contained at least one radiopaque oxide component such as BaO, ZrO2 and Yb2O3 with varying concentrations. In general, the radiopacity of the composite resin was linearly proportional to the amount of the radiopaque oxide in the filler. It was suggested that ZrO2 was radiopacifier equivalent to, or even stronger than, BaO.
Periodontal cell migration into the apical pulp during the repair process after pulpectomy in immature teeth: an autoradiographic study
Authors: VOJINOVIĆ O. , VOJINOVIĆ J. 
Published: June 2007

SummaryThe migration of dental papilla cells into the periodontium during the process of root development may occur as part of the process involved in the formation of the periodontal tissues. The question posed is whether such cells under pathological conditions could retromigrate from periodontium into dental pulp and together with other apical pulp cells of immature teeth, take part in the production of additional dental tissue, e.g. 1) the tertiary/dentine under deep carious lesion where odontoblasts had been destroyed 2) the dentine bridge on an amputation wound and 3) calcfied tissue which closes an apex during the apexification process in immature teeth.The migration of periodontal cells locally marked by H3 Thymidine immediately after partial pulpectomy in immature dog's teeth* was analysed at observation periods of 2, 24 and 50 h and also without H3 Thymidine labelling of periodontal cells 8 weeks after pulpectomy. The marked cells were found in the early observation periods after pulpectomy just in the places where the hard tissues were formed in the later observation period of 8 weeks. They were found in large numbers just around the coagulated necrotic foci. The finding supports the assumption that firm necrotic masses are a very important stimulative factor in the reparation process in pulp and periodontium. The experiment also corroborated the existence of periodontal cell retromigration into apical dental papilla of immature teeth. Future research should assess the possible role of the pathological condition in the determination of undifferentiated odontogenic ectomesenchymal periodontal cells into odontoblasts.