bluuebunny/crossref_metadata_2025 huggingface dataset:
Clinical performance of resin‐bonded bridges: a 5‐year prospective study. I. Design of the study and influence of experimental variables
Authors: CREUGERS N. H. J. , SNOEK P. A. , VAN'T HOF M. A. , KÄYSER A.F.
Published: June 2007

A total of 203 resin‐bonded bridges were inserted under controlled clinical conditions and evaluated over a period of 5 years. The study included two experiments to test the influences of retainer type, cementation material and operator on the success rate of resin‐bonded bridges. The overall survival at 5 years was 75%. Micromechanical retainers were better than macromechanical retainers. For inserting micromechanical retainers, the cementation materials Clearfil F and Panavia Ex were better than Conclude. An operator effect was not found in this study.
Solubility of zinc oxide‐eugenol and calcium hydroxide cements in simulated dentinal fluid
Authors: DRISCOLL C. F. , WOOLSEY G. D. , REDDY T. G. , CRAIG R. G.
Published: June 2007

The solubility of four dental cement bases was measured in simulated dentinal fluid and distilled water to evaluate the relevancy of the American Dental Association solubility test for cement bases in contact with vital dentine. A simulated dentinal fluid was formulated utilizing glucose, distilled water, and sterile human plasma. Cement‐base samples were immersed in either distilled water or simulated dentinal fluid at 37°C in a shaker water‐bath for 1, 2, or 3 months. Weight loss values were compared utilizing a three‐way analysis of variance. Zinc oxide‐eugenol cements were significantly more soluble in simulated dentinal fluid than distilled water, while the calcium hydroxide cement bases were significantly more soluble in distilled water than simulated dentinal fluid.
Effect of chewing training on mandibular postural position
Authors: TZAKIS M. , CARLSSON G. E. , KILIARIDIS S.
Published: June 2007

The inter‐occlusal rest space (free‐way space) was studied before and after short and long periods of chewing of a hard resin in 15 healthy subjects. During a month of daily training for one hour of chewing no significant changes in the interocclusal rest space were seen. After 30 min of intense chewing the mean interocclusal distance increased to about twice its original size. This occurred both before and after the training period. In a control group of eight subjects without any chewing exercise no significant changes in the interocclusal rest space were noticed during the observation period.
Relative influence of plaque control, scaling and root planing on occlusal sounds
Authors: MURAMOTO T. , TAGUCHI S. , ASAZUMA Y. , KIFUNE R. , HONMA S. , TSUCHIDA K. , HARA K.
Published: June 2007

Nine periodontally affected subjects and eight healthy subjects were selected in order to examine the effect of initial periodontal treatment on occlusal sounds. Gingival Index, probing depth, tooth mobility and occlusal sound duration via an occlusal sound analyser were recorded at the baseline. The nine periodontal patients were then treated by plaque control, root planing with general scaling and were re‐examined at 1 month and 3 months post‐operatively.

The following results were obtained:

(i) The normal duration of an occlusal sound is less than 10 ms.

(ii) Occlusal sounds of periodontal patients were of longer duration compared with the values in healthy subjects, but decreased and approached the normal value after treatment.
Comparison of the dimensional stability of two waxes and two acrylic resin processing techniques in the production of complete dentures
Authors: SYKORA O. , SUTOW E. J.
Published: June 2007

Two base plate waxes and two denture processing techniques were independently compared for dimensional stability. Occlusion rims were constructed from extra hard and medium soft base plate waxes and teeth were set. Acrylic resin bases were processed by a trial packing technique, and a continuous injection system. Tooth movement was measured in the horizontal and vertical planes to assess wax and denture base dimensional changes at various steps in the process, and after 1, 3, and 8 weeks of denture base immersion in water at room temperature. Posterior palatal border adaptation, incisal pin opening and loss of centric occlusion contacts, were also measured. Results showed there were no significant differences between the two waxes as determined by tooth movement in the horizontal and vertical planes. In comparison to the trial packing technique, the continuous injection system showed significantly smaller changes for incisal pin opening and loss of centric occlusion, and better adaptation of the posterior palatal border to the cast. Measurement of tooth movement in the horizontal and vertical planes showed no significant differences between the two processing techniques for times prior to immersion in water, whereas after 8 weeks immersion the continuous injection technique showed smaller dimensional changes, relative to the original dimensions at the time of investing.
Personality and anxiety in temporomandibular joint syndrome patients
Authors: SOUTHWELL J. , DEARY I.J. , GEISSLER P.
Published: June 2007

Much research has suggested that anxiety is involved in the temporomandibular joint syndrome (TMJ), but it is not clear whether it is a cause or a consequence of the disorder. The present study attempts to resolve this issue. Thirty‐two patients suffering from temporomandibular joint syndrome and 32 sex‐ and age‐matched dental clinic controls completed the Spielberger State‐Trait Anxiety Inventory, the Eysenck Personality Questionnaire and a standardized inventory of bodily symptomatology. TMJ patients scored significantly higher on Eysenck's neuroticism and introversion scales (both P < 0.05) and had higher trait anxiety scores (P < 0.005) when compared with controls. These results suggest that TMJ patients have personalities that are vulnerable to life stresses, but that they are not more anxious than controls at any given time. Such a personality profile is similar to that found in other ‘functional’ syndrome patient groups, such as individuals with globus pharyngis. We suggest that certain stress prone personalities express anxiety in the form of a predictable set of physical syndromes which may be subject to changes with time.
Number of remaining teeth and rehabilitation with removable dentures in psoriatics
Authors: KÖNÖNEN M. , MURTOMAA H.
Published: June 2007

The aim of this investigation was to study associations between the state of dentition and socio‐medical aspects in psoriatics.

It was found that the number of remaining teeth in subjects under 65 years of age was higher in psoriatics with skin symptoms (P‐group) than in psoriatics with skin and joint symptoms (PA‐group) (P<0.01), this rate being higher than that found among the general population in Finland. In younger subjects, women in the P‐group wore removable dentures more frequently than did women in the PA‐group (P<0.05), whereas among older subjects men in the PA‐group wore removable dentures more frequently than did men in the P‐group (P<0.001). In the log‐linear model that was applied, more advanced age, lower level of education and infrequent dental visits were associated with a low number of remaining teeth in both the P‐group and the PA‐group. A poor general state of health in the P‐group and a high number of teeth, indicating that there is an association between severity of general disease and dental health status.
Custom overdenture retainer
Authors: NEMCOVSKY C.E. , FITZIG S. , GROSS M.
Published: June 2007

A simple technique for fabricating stud overdenture retainers in the form of custom attachment castings with teflon retention discs has been described. This system allows for selective placement of the retention sphere on the root surface and control of retention through the size of the retention sphere. Using transfer location projections, exact transfer of the castings to the working model is possible. When necessary, the teflon discs may easily be replaced at the chairside.
Further studies of some masticatory characteristics of bruxism
Authors: FAULKNER K.D.B.
Published: June 2007

Quantitative analysis of a time dependent factor of jaw movement has shown there to be a significant difference in the muscle physiology of non‐bruxist and bruxist subjects.

Because bruxism can be difficult to detect in some patients, these results indicate that further development of the technique of jaw movement analysis might be useful as a diagnostic tool. They also point to the value of further study into the possible detection of ‘potential’ bruxists, thus allowing the development of a preventive aspect of bruxism.
Cu‐Ti, Co‐Ti and Ni‐Ti systems: corrosion and microhardness
Authors: CHERN LIN J.‐H. , MOSER J.B. , TAIRA M. , GREENER E.H.
Published: June 2007

Titanium alloys of 10 wt % ‐72 wt % Cu, 10 wt % ‐80 wt % Co and 20 wt % ‐84 wt% Ni were investigated. Ingots were fabricated in a vacuum/argon tungsten arc furnace. The surfaces of the alloys were examined by optical microscopy and SEM/EDS, and the Knoop hardness values of the alloys were measured. The corrosion resistance of the alloys was determined by a potentiodynamic polarization technique in buffered Ringer's solution. When a threshold composition of 30 wt % alloy was reached, a large decrease in corrosion resistance was found to occur. Knoop hardness measurements showed that similar hardness values of approximately 300 KHN can be obtained in all systems with lower alloy content. These values are similar to those obtained with a commercial dental titanium alloy.
Sensitivity to ambient light of visible light‐cured composites
Authors: DIONYSOPOULOS P. , WATTS D. C.
Published: June 2007

Fourteen representative visible light‐cured composite materials, including a total of 29 shades, have been examined for sensitivity to ambient light. The assessment was based upon a procedure recommended in an International Standard (ISO/DIS 4049). All but four of the 29 formulations exceeded the critical working time of 60 s when exposed to ambient illumination of 20 klx. These four composite resins exhibited working times greater than 60 s under 10 klx illumination, and the maximum working time observed at 10 klx was 227 s. These data confirm the finite working time of light‐cured resins under clinical lighting conditions.
Long‐term use of dentine adhesive as an interfacial sealer under Class II amalgam restorations
Authors: BEN‐AMAR A. , LIBERMAN R. , JUDES H. , NORDENBERG D.
Published: June 2007

An in vitro study was carried out to evaluate the long‐term sealing properties of a light‐cured dentine adhesive in Class II amalgam restorations. The restorations were subjected to repeated vertical occlusal loads and a number of thermocycling procedures. The results demonstrated significant advantages of using a dentine adhesive as an interfacial sealer in order to reduce microleakage, compared to a conventional Copal varnish.
A comparative study between three ethnic groups to derive some standards for maxillary arch dimensions
Authors: DIWAN R. , ELAHI J. M.
Published: June 2007

A sample of 91 adult Philippinos, 45 males and 46 females, were selected for maxillary arch measurements. The intercanine width (C‐C), intermolar width (M‐M), molar incisor (M‐I) and molar canine (M‐C) length were measured. The measurements were compared to previous studies of maxillary arch dimensions for adult male and female Egyptians and Saudi Arabians. The results showed wider (M‐M) measurements for the Egyptians than for the Philippinos, who also showed wider (C‐C) arch dimensions than the Saudi Arabians.
Method for identification and classification of single motor unit potentials in diagnostic electromyography
Authors: WIDMALM S.‐E. , ASH MAJOR M.
Published: June 2007

It is important to have an objective method for recording jaw muscle capacity such as EMG before, during and after treatment of muscle dysfunction and also for oral rehabilitation with dentures, implants or other types of restorations. Because measurements of motor unit potentials (MUPs) are needed in several areas of EMG analysis, algorithms have been developed in our laboratory for use in a small computer‐aided system for semi‐automatic detection and pattern recognition of MUPs. Based upon the test recordings it is suggested that a characteristic ‘maximal voltage increase per μs during the spike‐phase’ can be used as a supplement to the more generally used parameter ‘rise‐time’. Examples are given of how the programs can be useful in the study of the functional anatomy of jaw muscles by recording normative values for MUPs and their recruitment patterns.
Wear of composite resin in vitro: a testing machine with rubber plate. Preliminary results
Authors: HENGCHANG X. , VINGERLING P. A. , WENYI L. , GANG Z. , TONG W.
Published: June 2007

A new machine was developed to study the wear of dental filling materials in vitro. Four products: amalgam, Adaptic, Clearfil and acrylic resin were tested. Wear was measured quantitatively by weighing the specimen, and the wear pattern was studied qualitatively with a scanning electron microscope (SEM). A comparison was made with materials that were placed in the mouth for a prolonged period. It was found that the in vitro wear pattern was comparable to that found in vivo.
A potential MRI hazard: forces on dental magnet keepers
Authors: GEGAUFF A.G. , LAURELL K.A. , THAVENDRARAJAH A. , ROSENSTIEL S.F.
Published: June 2007

The objective of this study was to determine the forces on dental prosthetic magnet keepers, with a view to assessing the potential for patient injury during magnetic resonance imaging (MRI). Four pre‐formed keepers and one castable keeper alloy were tested. Magnetizations and high field susceptibilities were determined for each of the five specimens using data from a vibrating sample magnetometer. The magnetic field intensity with respect to distance from the main magnet coil was obtained from the manufacturer (1–5 tesla General Electric Signa Imaging System)*. A plot of force versus distance from the main coil and the maximum force at the magnet portal was determined for each specimen. The maximum forces ranged from 0.12–0.24N for the pre‐formed keepers and 3.67 MNm−3 for the castable alloy. It was concluded that the risk of patient injury by displacement is minimal, if the keepers are properly attached to supporting structures.
Electrical potentials of restorations in subjects without oral complaints
Authors: MULLER A.W.J. , VAN LOON L.A.J. , DAVIDSON C.L.
Published: June 2007

The electrical potentials of 183 amalgam and 11 precious metal restorations, and one set of brackets, were measured. None of the 28 subjects had galvanism, leukoplakia, oral lichen planus, or toxic or allergic reactions to restorations. The potentials of the amalgam restorations increased with age, from about −350 mV NHE at 30 days, to about +100 mV NHE after more than 1000 days. In most subjects potential differences of more than 50 mV were present between restorations; this phenomenon is therefore assumed to be common in healthy populations.
Dental cutting behaviour of mica‐based and apatite‐based machinable glass‐ceramics
Authors: TAIRA M. , WAKASA K. , YAMAKI M. , MATSUI A.
Published: June 2007

Some recently developed industrial ceramics have excellent machinability properties. The objective of this study was to evaluate the dental cutting behaviour of two machinable glass‐ceramics, mica‐containing Macor‐M® and apatite‐ and diopsidecontaining Bioram‐M®, and to compare them with the cutting behaviour of a composite resin typodont tooth enamel and bovine enamel. Weight‐load cutting tests were conducted, using a diamond point driven by an air‐turbine handpiece. While the transverse load applied on the point was varied, the handpiece speed during cutting and the volume of removal upon cutting were measured. In general, an increase in the applied load caused a decrease in cutting speed and an increase in cutting volume. However, the intensity of this trend was found to differ between four workpieces. Cutting Macor‐M® resulted in the second‐most reduced cutting speed and the maximum cutting volume. Cutting Bioram‐M® gave the least reduced cutting speed and the minimum cutting volume. It was suggested that two machinable glass‐ceramics could be employed as typodont teeth. This study may also contribute to the development of new restorative dental ceramic materials, prepared by machining.
Clinical oral test for the assessment of oral symptoms of glossodynia and glossopyrosis
Authors: CEKIĆ‐ARAMBAŠIN A. , VIDAS I. , STIPETIĆ‐MRAVAK M.
Published: June 2007

Subjective oral symptoms of a burning sensation and pain in the tongue may exist in the absence of any pathological changes in the oral mucosa. Owing to different treatment approaches and the lack of any specific therapy, it appeared potentially useful to identify these subjective symptoms by means of a test for an improved therapy evaluation. In this study, we have attempted to develop a method for the objective assessment of oral symptoms of glossodynia and glossopyrosis, by recording the local temperature. The temperature of the tongue was determined using a DT‐1 electron thermoesthesiometer, that was highly sensitive to temperatures between 36°C and 38°C. Measurements were performed in topographic areas recommended by the World Health Organization in 1980. The study sample consisted of a group of 50 patients with glossopyrosis and glossodynia, without any clinically manifest pathological changes in the oral cavity, who were compared with a group of 50 age‐ and sexmatched subjects free of these oral symptoms and with normal oral mucosa. Statistically significant temperature differences were observed between the patients and the controls, as measured in seven different areas. The lowest temperatures (33°C) were measured in the apex linguae area. The minimum temperature was significantly lower in the study group. Significant differences in temperature were also observed between the sexes. It was concluded that glossodynia and glossopyrosis, both inflammation and diminished circulation without any visible clinical signs, can be diagnosed using the thermoesthesiometry test. Such an objective test allows appropriate therapeutic treatment to be selected for patients with the above‐mentioned symptoms.
The effects of dentine bonding agents on marginal leakage of composite restorations
Authors: SAUNDERS W. P. , GRIEVE A. R. , RUSSELL E. M. , ALANI A. H.
Published: June 2007

The aim of this study was to compare the effects upon marginal leakage of a number of dentine bonding agents: Gluma, Scotchbond, Topaz and an experimental material when used with a posterior composite resin, Occlusin. The results were also compared with composite used without a dentine bonding agent and 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 3 months and then thermally cycled. Marginal leakage was subsequently determined using a radioactive isotope containing 45Ca, and an autoradiographic 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 non‐bevelled type. The use of dentine bonding agents did not improve the marginal seal of the composite restorations, and the glass ionomer restorations showed significantly less leakage than the composite resin and dentine bonding agent combinations.
Studies on fracture toughness of dental ceramics
Authors: TAIRA M. , NOMURA Y. , WAKASA K. , YAMAKI M. , MATSUI A.
Published: June 2007

One important mechanical property of dental ceramics is fracture toughness, KIC, which represents the serviceability in the oral cavity, such as the resistance to marginal fracture. KIC values of several dental ceramics, natural tooth enamel and industrial ceramics were examined by use of the indentation microfracture (IM) method. This technique was based on the series of radial cracks emanating from the corners of the Vickers indentation. It was observed that appropriate load levels should be selected on each specimen to induce radial/median cracks. For feldspatic dental porcelains, larger loads of 10, 20 and 30 kg were needed to determine their KIC values in the range 1.5–2.1 MN‐rn−3/2. For natural tooth enamel and a new apatite‐based castable glass‐ceramic, a smaller force of 1 kg was sufficient to decide the respective KIC values of about 0.9 and 1.8 MN‐m−3/2. The KIC values of most dental ceramics examined were slightly higher than that of soda lime glass, but less than one‐third that of zirconia. It was confirmed that the IM method is simple and cost‐effective for evaluation of KIC of dental ceramics.
Mandibular movement and velocity in relation to state of dentition and age
Authors: KARLSSON S. , PERSSON M. , CARLSSON G. E.
Published: June 2007

Parameters of mastication, such as mandibular displacement, velocity and chewing cycle duration, were investigated in relation to age and rehabilitation with complete dentures. Two groups of elderly subjects (mean age 80 years), one with natural dentition and the other with complete dentures, and one group of young dentate adults (mean age 26 years) participated. Three‐dimensional records of masticatory mandibular movements were obtained using the Selspot movement analysis system.

There were no differences in the duration of the total or individual components of a chewing cycle, except for the closing phase, which was significantly longer in the complete denture group. Mandibular closing velocity was significantly lower in the two groups of elderly subjects than in the group of young adults. There was a high degree of inter‐individual variation in mandibular displacement in all groups, but the mean vertical amplitude was smaller in the elderly groups compared to the group of young adults. For many of the parameters the variation was significantly greater in the groups of elderly subjects than in the younger group. Ageing thus appeared to have a more important effect than the state of the dentition on the parameters studied.
Replication of human occlusal tooth attrition surfaces for scanning electron microscopic study
Authors: AKPATA E. S. , WINTER P. J.
Published: June 2007

Silicone negative replicas of dentine islands exposed by occlusal attrition were examined on extracted human teeth using the scanning electron microscope. Because the details of the dentinal tubules were reproducible on the silicone impression, the replication technique was applied in vivo to occlusal attrition to demonstrate patent dentinal tubules in cases with symptomatic exposed dentine islands.

Using this replication technique, it should be possible to monitor the effect of the therapeutic management of symptomatic tooth attrition on dentinal tubule closure.
Dental amalgams subjected to sub‐fracture stresses at 37°C
Authors: GERZINA T.M. , WING G.
Published: June 2007

Amalgam beam specimens were subjected to sub‐modulus of rupture loads at 37°C. The specimens tested underwent varying degrees of deformation and ultimate fracture determined by the degree of specimen bend and time to fracture. The property most closely related to the sub‐fracture loading behaviour was creep, particularly the 72‐h determination of this property. Time and temperature of testing are also significant factors.

The present study indicates the importance of the use of 37°C testing in low‐load stressing of dental amalgam. The study has confirmed the nature of failure of amalgam in relation to its rheological properties at the temperature at which amalgam functions clinically.
Parotid salivary flow rates in two patients during immediate denture treatment
Authors: JENSEN J.C.L. , BRODIN P. , ØRSTAVIK J.
Published: June 2007

Parotid salivary flow rates in response to chewing or citric acid stimulation were studied in two patients who had their last maxillary teeth extracted and immediately replaced with complete dentures. The patients were monitored 6 months from the last week before extraction.

Parotid salivary flow rate in response to chewing was increased after insertion of the denture. For one of the patients a particularly high output from the parotid gland was found 2 weeks after treatment. Throughout the experiment, parotid salivary flow was higher on the chewing side than on the contralateral side. At the end of the experimental period the dentures were relined. Salivary flow measured immediately after relining was lower than prior to this procedure.

An increased salivary response was also observed during citric acid stimulation after transition from the dentate to the denture wearing state. This increase was more marked if the patients had their dentures in situ when the gustatory provocations were performed.

It is concluded that parotid salivation increases during masticatory and gustatory stimulation in patients subjected to total extraction and immediate complete denture treatment, and that the presence of a complete denture per se appears to act as an additional mechanical stimulus in the salivary reflexes.
Changes in compressive strength of glass ionomer restorative materials with respect to time periods of 24 h to 4 months
Authors: WILLIAMS J.A. , BILLINGTON R.W.
Published: June 2007

This study investigated whether long‐term changes occur in the compressive strength of a number of glass ionomer restorative materials, in view of the fact that little information is available from the manufacturers, and any variations with time might affect suitability for clinical use.

It was found that, over the period of 24 h to 4 months, some materials, namely those based on polyacrylic acid, maintained or even showed a slight increase in their strength, whereas others based on copolymers of acrylic acid first increased in strength, but thereafter showed deterioration. In one case the strength decreased by nearly 50% compared to that at 24 h.
The relationship between the isotonic mechanical power in jaw‐opening and jaw‐closing muscles in man
Authors: WATANABE K. , SHIMIZU K. , NAKATA S. , WATANABE M.
Published: June 2007

The relationship between isotonic jaw‐opening and jaw‐closing muscle function was studied using a newly developed apparatus which enables load and velocity to be detected simultaneously. The following results were obtained from 17 male adults(age range 22–23 years) without any occlusal dysfunction.

(i) The force‐velocity relationship in jaw‐opening and jaw‐closing muscles was represented by a hyperbolic curve, which fitted well with Hill's equation.

(ii) The theoretical maximum force obtained by extrapolation from regression was 32.55±4.98 kg for jaw opening and 35.74±4.52 kg for jaw closing.

(iii) The theoretical maximum velocity obtained by extrapolation from regression was 456.70±183.27 mm s−1 for jaw opening and 372.77±141.67 mm s−1 for jaw closing.

(iv) The maximum mechanical power (Pmax) calculated from the product of the force and velocity was 772.20±182.65 kg.mm s−1 for jaw opening and 708.68±128.14 kg.mm s−1 for jaw closing.

(v) The Pmax exerted by individual subjects was approximately 12–34% of the maximum possible force (Fmax) calculated from the force and velocity, in both jaw opening and jaw closing.

There were no statistically significant differences between jaw opening and jaw closing with regard to any isotonic muscle functions. In other words, the results of this study strongly indicated a substantial balance between isotonic jaw‐opening and jaw‐closing muscle function in the subjects who were investigated.
Power spectral analysis of occlusal sounds of natural dentition subjects
Authors: CHONG‐SHAN SHI , GUAN OUYANG , TIAN‐WEN GUO
Published: June 2007

Fifteen subjects with complete natural dentitions were selected for investigation of their occlusal sounds on the left and right sides by means of power spectral analysis. It was found that the occlusal sounds consisted of various frequency componets. Their mean power frequencies (MPF) and frequences at 10, 20, 50, 80 and 90% of cumulative powre (F10, F20, F50, F80, F90) on the left and right sides were almost identical (P<0.05). The correlation coefficients between MPF and F50, MPF and F50 with the others were high. The results indicate that F20, MPF or F50 and F80 may be used as indices to describe the power spectral shape, and that power spectral analysis of occlusal sounds may be used as a contribution to diagnosis of occlusal conditions.
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

By 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

The 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

The 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.
Determining the accuracy of gypsum casts made from type IV dental stone
Authors: MILLSTEIN P.L.
Published: June 2007

A study was conducted to evaluate the accuracy of casts made in Type IV dental stone. The results indicate that all casts distort, but that significant differences exist between various brands of die stone.
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

Not 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

Surgical 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

There 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.
Remarks on probability theory and TMJ diagnosis
Authors: CHRISTENSEN L.V. , ASH M.M.
Published: June 2007

On the basis of the classic concepts of events and probability theory, this article analyzes some recently introduced diagnostic probability concepts as they pertain to temporomandibular joint (TMJ) diseases and disorders.
Filler particle size and composite resin classification systems
Authors: LANG B.R. , JAARDA M. , WANG R.‐F.
Published: June 2007

The 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

The 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

The 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

Maxillofacial 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

Using 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

Selected 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

The 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

In 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.
Enamel surface roughness analysis after laser ablation and acid‐etching
Authors: ARCORIA C.J. , LIPPAS M.G. , VITASEK B.A.
Published: June 2007

Laser‐roughened enamel surfaces have been shown to provide for greater acid‐resistance and enhanced restorative material/enamel bond strength. Extracted tooth enamel was irradiated with several lasers: CO2/Nd:YAG (CW), CO2 (RSP), Nd:YAG (CW), Nd:YAG (Q‐switched), Argon (CW), and Ar:F excimer. Additional teeth were acid‐etched. Energy densities were standardized at 25‐47 J/cm2 for all mediums. Surface profile analyses were conducted with a profilometer to determine the amount of enamel surface roughness. The acid‐etched samples exhibited both a greater amount of surface roughness and a qualitatively different type of enamel surface morphology than the laser‐treated specimens. Independent use of the CO2 and Nd:YAG beams exhibited a moderate amount of roughness, while the coaxial CO2/Nd:YAG beam displayed surface roughness approaching that of the acid‐etch samples. Different laser mediums produce enamel surface morphologies that are characteristic of a variety of inherent lasing parameters.
Contribution of periodontal receptors and food qualities to masseter muscle inhibition in man
Authors: MÜLLER F. , HEATH M.R. , KAZAZOGLU E. , HECTOR M.P.
Published: June 2007

Previous studies of human muscle inhibition during chewing have shown that many factors contribute to the incidence and intensity of this reflex but few studies have been in a physiological context. During the first crushing cycle of brittle foods ipsilateral masseter muscle EMG, mandibular movement and vibration were recorded simultaneously in four healthy dentate subjects. Experiments were repeated before and during anaesthesia of the cheek teeth on the chewing side. The results suggest that vibration seems to be the most important factor in muscle inhibition during food crushing; conversely periodontal sensation, mandibular closing movement and the preload by the muscle at the onset of food fracture play a minor role.