bluuebunny/crossref_metadata_2025 huggingface dataset:
Masticatory muscle activity in myotonic dystrophy patients
Authors: ÖDMAN C. , KILIARIDIS S.
Published: May 2007

summary
The aim of the study was to compare the masticatory pattern and the activity of the masticatory muscles of a group of myotonic dystrophy patients with those of a group of healthy individuals. The electromyographic (EMG) activity of the temporal and the masseter muscles was measured in the resting position, during maximal clenching, and while the patient was chewing five peanuts until swallowing. It was found that the patients had approximately 3 times less EMG activity in the masticatory muscles during maximal clenching. During chewing the patients had approximately half the activity in the anterior temporal and the masseter muscles, while the activity of the posterior temporal muscle did not differ significantly from that in healthy individuals. No differences were found in the muscle activity in the resting position or in the speed of chewing between the groups. The patients needed more time and more chewing cycles to bring the five peanuts to the swallowing threshold, but possibly this was an effect of the lower number of antagonizing teeth. Myotonic dystrophy thus influences the masticatory muscles, reducing their activity both at a maximal and a functional level.
Evaluation of masticatory muscles of edentulous patients by computed tomography and electromyography
Authors: RAUSTIA A. M. , SALONEN M.A.M. , PYHTINEN J.
Published: May 2007

summary
On account of its tissue resolution capacity, computed tomography (CT) is an excellent method for the examination and quantitative analysis of the masticatory muscles. The aim of the present study was to evaluate the influence of the long edentulous period by CT on the structure of the main masticatory muscles in 10 edentulous patients and to study their functioning by electromyography (EMG) in connection with the renewal of the dentures. CT scanning was performed before prosthodontic treatment and EMG recordings of the masseter and temporal muscles before treatment and 4 weeks and 6 months after insertion of the new dentures. The results suggest, however, that a long edentulous period is visible not only in the functioning of the masticatory muscles, in terms of decreased EMG activity, but also as decreased density of the muscles which implies muscle atrophy, as seen by CT in the masseter and medial pterygoid muscles.
The relationship between maximal jaw opening and size of skeleton: a cephalometric study
Authors: MUTO T. , KANAZAWA M.
Published: May 2007

summary
The purpose of this study was to investigate the correlation between maximal mouth opening and size of the skeleton. The subjects were dental students at the Dental School of the Health Sciences University of Hokkaido with no functional disorders of the masticatory system. The stature and maximal mouth opening were recorded in 29 males and 31 females. These subjects agreed to have a lateral cephalogram taken at the closed and maximal mouth opening positions. The correlations between the maximal mouth opening and the body height, mandibular length and mandibular angle were significant. The correlation between the maximal mouth opening and the movement of the condyle was also significant.
Development and evaluation of a new 3‐D digitization and computer graphic system to study the anatomic tissue and restoration surfaces
Authors: DASTANE A. , VAIDYANATHAN T.K. , VAIDYANATHAN J. , MEHRA R. , HESBY R.
Published: May 2007

summary
It is necessary to visualize and reconstruct tissue anatomic surfaces accurately for a variety of oral rehabilitation applications such as surface wear characterization and automated fabrication of dental restorations, accuracy of reproduction of impression and die materials, etc. In this investigation, a 3‐D digitization and computer‐graphic system was developed for surface characterization. The hardware consists of a profiler assembly for digitization in an MTS biomechanical test system with an artificial mouth, an IBM PS/2 computer model 70 for data processing and a Hewlett‐Packard laser printer for hardcopy outputs. The software used includes a commercially available Surfer 3‐D graphics package, a public domain data‐fitting alignment software and an inhouse Pascal program for intercommunication plus some other limited tasks. Surfaces were digitized before and after rotation by angular displacement, the digital data were interpolated by Surfer to provide a data grid and the surfaces were computer graphically reconstructed: Misaligned surfaces were aligned by the data‐fitting alignment software under different choices of parameters. The effect of different interpolation parameters (e.g. grid size, method of interpolation) and extent of rotation on the alignment accuracy was determined. The results indicate that improved alignment accuracy results from optimization of interpolation parameters and minimization of the initial misorientation between the digitized surfaces. The method provides important advantages for surface reconstruction and visualization, such as overlay of sequentially generated surfaces and accurate alignment of pairs of surfaces with small misalignment.
Influence of experimental occlusal discrepancy on masticatory muscle activity during clenching
Authors: BABA K. , AI M. , MIZUTANI H. , ENOSAWA S.
Published: May 2007

summary
The influence of the experimental occlusal discrepancy on masticatory muscle activity was investigated on 12 subjects. Specially designed occlusal interferences were fabricated and various occlusal states were simulated with their aid. Subjects were asked to carry out eccentric clenching efforts and electromyographic activity of the masseter plus the anterior and posterior temporal muscles was measured. When compared with clenching on the unaltered natural dentition, clenching on the experimental interferences resulted in distinct patterns in the jaw elevator muscles, and the most characteristic change was observed when clenching effort was exerted on the experimental non‐working side interference. Electromyographic activity in the anterior and posterior temporal muscles was decreased on the working side and increased on the non‐working side and originally unilateral activity pattern with clear dominance on the working side was altered to a bilateral pattern, while that of the masseter muscles remained uninfluenced. Resultant bilateral activity in the anterior and posterior temporal muscles is thought to cause a superior movement of the working side condyle and an inferior movement of the non‐working side condyle.
Microleakage of direct and indirect inlay/onlay systems
Authors: HASANREÎARSOǦARLU U. , SÖNMEZ H. , ÜÇTAŞLI S. , WILSON H.J.
Published: May 2007

summary
The purpose of this in vitro study was to evalu ate the microleakage of direct and indirect inlay/onlay systems. Two of the groups investigated have indirect applications only and consist of microfine composites. The other two groups of inlay/onlay systems have both direct and indirect applications and are hybrid compos ites. Standardized MOD preparations were cut in 60 extracted human premolars. One gingival margin was placed in enamel above the cementoenamel junction (CEJ) and the other was placed in dentine below the CEJ. The inlays were made and luted according to each manufacturer's recommendation. The restored teeth were thermocycled and immersed in a basic fuchsin solution for 24 h. Following the mesiodistal sectioning of the specimens, extent of dye penetration at the restoration‐glass ionomer cement and tooth‐glass ionomer cement interfaces were scored using a stereomicroscope. Both direct and indirect inlays showed substantial leakage at gingival‐dentine mar gins. However, there was only superficial leakage at enamel margins. Comparing the overall indirect inlay systems, EOS inlay leaked the most (P≤0.05). Indirect Brilliant Dentin® inlays showed a significantly smaller amount of leakage than the other inlay systems. SR‐ Isosit® and Estilux Posterior C VS® inlays provided a favourable marginal seal. In the case of Brilliant Dentin® and Estilux Posterior C VS®, indirect inlays leaked more than direct inlays. Generally, no significant difference was observed between the interfaces evaluated in microleakage performance.
The importance of a multidisciplinary approach to the assessment of patients with obstructive sleep apnoea*
Authors: L'ESTRANGE P.R. , BATTAGEL J.M. , NOLAN P. J. , HARKNESS B. , JORGENSEN G.I.
Published: May 2007

summary
Obstructive sleep apnoea may present with a wide range of symptoms resulting in a variety of referral pathways. A multidisciplinary approach to examination and diagnosis helps to determine the most appropriate treatment plan for each individual. The subject is seen by each member of the team, appropriate investigations undertaken and a further meeting arranged at which all opinions are discussed. A reasoned treatment regime is produced, taking into consideration the patient's wishes and overall medical condition. This paper describes the team approach currently employed in the Department of Thoracic Medicine at The Prince Charles Hospital, Brisbane, Australia. The thoracic physician and ENT surgeon work in close collaboration with their dental colleagues: an orthodontist, prosthodontist and a maxillofacial surgeon. An outline of the examination and investigations made by each is described and the multidisciplinary approach is illustrated by a des cription of the management of five subjects with suspected obstructive sleep apnoea.
The prevalence of toothwear in 1007 dental patients
Authors: SMITH B.G.N. , ROBB N.D.
Published: May 2007

summary
The dental profession is becoming increasingly concerned about unacceptable levels of tooth‐wear and there is an impression that the condition is becoming more prevalent. There is, as yet, little epidemiological evidence to illuminate the question and so this study is therefore intended to provide baseline data on the prevalence of toothwear in a sample of the dental attending population of South East England. A degree of toothwear is normal and progresses throughout life. Toothwear which is acceptable in an older age group would not be so with younger patients. It is therefore necessary to designate threshold values of acceptable levels of toothwear for different age groups to reach realistic conclusions about the prevalence of unacceptable levels of tooth‐wear. Of the 1007 patients examined only nine had completely unworn dentitions. More than 93,500 tooth surfaces were examined and of these 5.1% had wear which exceeded the threshold values. Despite increasing the threshold values for the older age groups from those proposed in an earlier study by Smith & Knight (1984), these patients still had higher levels of unacceptable toothwear. There was a slight tendency for men to have more wear than women, but there was no clinically significant relationship between the number of missing posterior teeth and wear of the anterior teeth
The effect of a vital bleaching technique on enamel surface morphology and the bonding of composite resin to enamel
Authors: JOSEY A.L. , MEYERS I.A. , ROMANIUK K. , SYMONS A.L.
Published: May 2007

summary
This study examined the effect of a nightguard vital bleaching procedure on enamel surface morphology and the shear bond strength of a composite resin luting cement to enamel. Extracted human teeth were bleached for 1 week using a vital bleaching product. Control teeth were brushed with a fluoride toothpaste and processed similarly to the bleached teeth, however the bleaching product was substituted with artificial saliva in the night guards. Teeth were stored in artificial saliva for 24 h, 1, 6 or 12 weeks and then examined for any surface changes using light and scanning electron microscopy. The effect of etching surfaces with 37% phosphoric acid was examined at the scanning electron microscope level. The shear bond strength of composite resin luting cement to both buccal and lingual surfaces of bleached and control teeth was determined. Light microscopy investigation suggested the bleaching process resulted in a loss of mineral from enamel which was evident 24 h after bleaching and was sustained following 12 weeks storage in artificial saliva. Scanning electron microscopy showed a definite change in the surface texture of the bleached enamel surface. Acid etching of the bleached enamel surface produced loss of prismatic form and the enamel appeared overetched. The mean shear bond strength between composite resin luting cement and etched enamel tended to be lower for bleached enamel surfaces, however no significant difference in shear bond strength was noted between control and experimental groups. The results of this study suggest that bleaching resulted in changes to the surface and subsurface layers of enamel. Although surface changes were observed in the etched enamel, the shear bond strength of composite resin luting cement to etched bleached enamel appeared to be clinically acceptable
The strength of a heat‐pressed all‐ceramic restorative material
Authors: UCTASLI S. , WILSON H.J. , UNTERBRINK G. , ZAIMOGLU A.
Published: May 2007

summary
A heat‐pressed technique (IPS Empress®, Ivoclar) has been described to construct single unit crowns, inlay/onlays and veneers using precerammed and precoloured glass‐ceramic ingots. The aim of the study was to evaluate the strength of materials obtained using this technique. Strengths were determined by means of shell (disc rupture) tests. Seven groups of 10 specimens each were prepared with different combinations of core, incisal and glaze firing. Shell strength values of these seven groups varied between 167 ± 18 and 81 ± 9 MPa. After analysis, results showed that there was no statistical difference between groups when the core porcelain was in tension. However, there was a significant difference between those groups in which the lower surface was either core or incisal porcelain. The component thicknesses of the core and incisal materials did not change the strength of the complete specimen.
Predictability of jaw muscle pains from surface electromyograms
Authors: CHRISTENSEN L.V. , TRAN K.T.
Published: May 2007

summary
In seven (88%) of eight healthy subjects, weak to moderate pains were elicited in the masseter muscles through the isometric contractions of maximum voluntary teeth clenching. Integrated surface electromyograms of the right and left masseter muscles were used to quantify the absolute and relative contractile activities of the two muscles. The risk (relative probability) of inducing pain onset in the single masseter muscle generating the larger amount of isometric activity was 2–5 times the risk of eliciting pain onset in the single masseter muscle generating the lesser amount of isometric activity. However, as an aid in the diagnosis of pain onset, the method of masseteric surface electromyography had a false diagnostic ratio of 0.67
The relationship between gastro‐oesophageal reflux disease and dental erosion
Authors: BARTLETT D.W. , EVANS D.F. , SMITH B.G.N.
Published: May 2007

summary
It is well known that acid regurgitated from the stomach into the mouth will erode teeth. Conditions such as anorexia and bulimia nervosa, chronic alcoholism and gastric disturbances cause palatal dental erosion. The common factor in these conditions is the role played by the stomach and oesophagus in the acid movement. Acid moving through the lower oesophageal sphincter into the oesophagus is described as gastro‐oesophageal reflux (GOR). In some patients the acid movement becomes chronic, painful and requires treatment and is termed gastro‐oesophageal reflux disease (GORD). It is felt by many gastroenterologists that GORD is a failure of the anti‐reflux mechanism, which is predominantly controlled by the lower oesophageal sphincter (LOS). Regurgitation is the reflux of gastric juice through the upper oesophageal sphincter and into the oral cavity. Once the acid has reached the mouth the potential exists for damage to the teeth. This paper reviews the role of GOR, GORD and regurgitation in the aetiology of dental erosion.
Influence of paste temperature at curing on conversion rate and bending strength of light‐cured dental composites
Authors: LI J. , NICANDER I. , VON BEETZEN M. , SUNDSTRÖM F.
Published: May 2007

summary
Pastes of three dental composites were tempered to 20°C, 37°C and 60°C. Test specimens (22 × 2 × 2 mm) were cured by light and stored in deionized water. Three‐point bending strength was measured after 1 h and after 24 h. Degree of conversion on the surface exposed to the curing light and the opposite surfaces at the bottom of the mould was analysed by Fourier transform infrared (FTIR) after 1 h. After 1 h, specimens produced using the pastes cured at 60°C showed significantly higher bending strength than the specimens produced using pastes cured at 20°C and 37°C. However, after 24 h the composites pretempered at the lower temperatures had developed the same level of bending strength as the composites cured at 60°C. An increase in the degree of conversion with increased paste temperature was found in all materials after 1 h.
Effects of food/oral simulating fluids on microstructure and strength of dentine bonding agents
Authors: LEE S.‐Y. , GREENER E.H. , COVEY D.A. , MENIS D.L.
Published: May 2007

summary
This study evaluated the effect a food simulating solution, 75% v/v ethanol/water, and an artificial saliva, Moi‐Stir, have on the microstructure and on the diametral tensile strength (DTS) of three dentine bonding agents (Tenure, Scotchbond Multipurpose and Optibond). The microstructure was examined by using a scanning electron microscope (SEM). The DTS data were analysed using ANOVA and the Tukey LSD test. The microstructural observations were compared with changes in DTS. The SEM observation revealed deterioration of all bonding agents due to conditioning in the solutions for 30 days. The different solutions appeared to cause different reactions in the bonding agents. However, these effects may be exaggerated due to the presence of an air‐inhibited surface layer. Those conditioned in Moi‐Stir showed swelling. The presence of filler particles in the Optibond bonding agent appears to decrease the deterioration resulting from soaking. Materials conditioned in ethanol exhibited both dissolution and thinning. Diametral samples of each bonding material were tested after being conditioned in the above‐mentioned solutions for 1, 7, 14 and 30 days. Conditioning significantly decreased the DTS of all bonding agents, except Optibond in Moi‐Stir. Filled Optibond maintained its DTS longer than did the two unfilled bonding agents. The decrease in DTS of all the ethanol‐conditioned groups is a function of the square root of time (P < 0‐001) and conforms to Ficks laws of diffusion. The filled Optibond showed a lower ethanol diffusivity (0‐5 × 10 5 cm2 s1) than the other two unfilled bonding agent systems (average 1–2 × 105cm 2s−1) (P < 005). The high ethanol diffusivities were thought to be due to the presence of HEMA, a hydrophilic resin, in the bonding agent. These results also suggest that solution uptake occurred through the resin matrix. Filler particles may therefore play an important role in weathering resistance of these materials to oral environment solutions. The physical appearance and strength of dentine bonding agents are significantly altered by exposure to oral environment solutions.
Craniomandibular stiffness in myogenous and arthrogenous CMD patients, and control subjects: a clinical and experimental investigation
Authors: HESSE J.R. , NAEIJE M. , HANSSON T.L.
Published: May 2007

summary
The purpose of this study was to compare active maximum mouth opening, endfeel distance, and craniomandibular stiffness values of three crani‐ omandibular disorder (CMD) patient subgroups and a control group. The CMD patient subgroups consisted of myogenous pain patients and arthrogenous pain patients with a ‘closed lock’ and arthrogenous pain patients without a ‘closed lock’. Both myogenous pain patients and the ‘closed lock’ patients showed great differences on all parameters (P < 0.05 – P < 0.001). However, the arthrogenous pain patients without a ‘closed lock’ revealed no statistical differences with the control group on any of the tested parameters.
Open–close movements in the human temporomandibular joint: does a pure rotation around the intercondylar hinge axis exist?
Authors: FERRARIO V.F. , SFORZA C. , JR MIANI A. , SERRAO G. , TARTAGLIA G.
Published: May 2007

summary
Mandibular movements near the maximum intercuspal position were analysed for the location of the mean instantaneous centre of curvature of the interincisal point path. Measurements were performed using a kinesiograph in 28 healthy young adults with sound dentitions and free from temporomandibular joint disorders. The subjects performed habitual open‐close cycles at different speeds; opening movements starting from the centric relation occlusion were also analysed. In none of the 28 subjects was the interincisal point path derived from pure rotation movements performed around the intercondylar axis, not even in the first millimetres of motion. Translation and rotation were always combined, and the position of the centre of curvature changed during the motion, showing different characteristics in the open and close movements; these patterns were also dependent upon motion speed. The results show that the hinge axis theory cannot explain the mandibular movements because a pure rotation did not occur around the intercondylar axis.
Cutting effectiveness of diamond points on commercial core composite resins and cements
Authors: MIYAWAKI H. , TAIRA M. , YAMAKI M.
Published: May 2007

summary
In dental clinics, composite resin and cement cores are routinely cut and polished during abutment tooth preparation. To identify their characteristics during cutting, weight‐load cutting tests were performed on eight commercial core composites and two cements, using diamond points driven by an air‐turbine handpiece. It became evident that the cutting effectiveness of the diamond points on nine workpieces exceeded that on natural tooth dentine, while that on one composite containing Si3N4 filler was analogous to that on dentine. With continued use, the cutting effectiveness of the diamond point on all workpieces gradually declined. SEM observations revealed that diamond particles of the diamond point wore out with repeated use. It is clinically advised to select the core material with material characteristics during cutting and mechanical strength similar to those of dentin.
Failure of dental bridges. II. Prevalence of failure and its relation to place of construction
Authors: FAYYAD M.A. , AL‐RAFEE M.A.
Published: May 2007

summary In this investigation 156 dental bridges, constructed for 132 individuals, were evaluated. The bridges inserted at the College of Dentistry, King Saud University (KSU), Saudi Arabia, were compared with those placed in general dental practice. The results revealed that the rate of bridge failure averaged 35.5%. This was made up from failure of bridges inserted at KSU at (15.4%) and those in general dental practice (46.2%). The major reasons for failure revealed by this study were periodontal disease (36.6%) and secondary caries (23.2%). The average lifespan for the bridges was 6.1 years with 4.5 years for the unfailed bridges. The most commonly used material for bridges was metal‐ceramics. The most commonly used pontic design was the modified ridge lap (50.8%), but the saddle type accounted for the greatest percentage of failures (59.6%).
Bonding of a mica‐based castable ceramic material with a tri‐n‐butylborane‐initiated adhesive resin
Authors: MORIKAWA T. , MATSUMURA H. , ATSUTA M.
Published: May 2007

SUMMARY
Adhesive bonding of a mica‐based castable ceramic material (Olympus Castable Ceramics, OCC) was evaluated in vitro with the use of a silane primer in conjunction with an adhesive luting material. The primer contained a silane coupler and 4‐methacryloxyethyl trimellitate anhydride (4‐META), while the methyl methacrylate (MMA)‐based luting agent was initiated with a tri‐n‐butylborane derivative (TBB) and contained 4‐META (4‐META/MMA‐TBB resin). Ceramic specimens were sanded with No. 600 silicon carbide paper followed by blasting with alumina and/or etching with ammonium bifluoride. The specimens were bonded with various combinations and shear bond strengths were determined. Both priming and alumina blasting enhanced the bond between 4‐META resin and OCC. Although etching with ammonium bifluoride roughened the ceramic surface, this procedure did not improve the bond strength. Electron probe microanalysis of the ceramic surface revealed a decrease in silicon and aluminium elements after etching with ammonium bifluoride.
Visual versus mechanical wear measurement of dental composite resin
Authors: WINKLER M.M. , LAUTENSCHLAGER E.P. , BOGHOSIAN A. , GREENERY E.H.
Published: May 2007

SUMMARY
This study compares a visual method for measuring composite wear with a relatively inexpensive mechanical technique. The visual measurements used a set of 17 graduated stone standards as the reference. Two sets of 10 unknown casts were evaluated. The first was a set of 10 stone replicas selected from the reference set in the range of 25–250 μm. The second set was composed of 10 casts of clinical restorations. The mechanical test employed a computer‐controlled custom profilometer. Depth was recorded at 50 equidistant positions around the margin. A significant correlation was found (r > 0.98) between the visual and mechanical means for both measurement techniques. Mean values were equivalent for the standard casts. However, visual estimation of the clinical casts were significantly lower (61% of mechanical values) and thus not accurate for clinical use.
The effect of topical fluoride agents on saliva secretion
Authors: ENGEL‐BRILL N. , GEDALIA I. , RAXN F. , FRIEDWALD E. , ROTMANN M. , ROSEN L.
Published: May 2007

SUMMARY
The aim of this study was to assess the possible influence of various topical fluoride agents on the rate of saliva secretion. Fifteen healthy volunteers, both males and females, aged 20–60 years, participated in this study. Aminfluorides and monofluorophosphate products in gel, toothpaste and rinse states were used. Each subject brushed or rinsed the teeth and mouth for 2 minutes. Secreted saliva was collected for 5 minutes. Salivary secretion was significantly greater after toothbrushing with amin‐fluoride compounds as compared to toothbrushing with monofluorophosphate. There was a tendency for an increased saliva flow rate with higher fluoride concentration of the aminfluoride.
Materials for endosseous dental implants
Authors: Wataha J. C.
Published: May 2007

summary
The goal of placement of endosseous dental implants is to achieve osseointegration or biointegration of the bone with the implant. A wide variety of materials has been used for these implants, but only a few promote osseointegration and biointegration. Titanium and titanium alloy (TJ6A14V) have been the most widely used of these materials. The surface oxide of titanium appears to be central to the ability of this material to osseointegrate. The oxide limits dissolution of elements and promotes the deposition of biological molecules which allow bone to exist as close as 30 å to the surface of the implant. The details of the ultrastructure of the gap between the implant and bone remain undefined, and the consequences of elements which are released on the interface over time are not known. These areas of investigation are particularly important in defining the differences between commercially pure titanium implants and those made of titanium, aluminium and vanadium. The epithelial interface between the gingiva and titanium appears to contain many of the structural characteristics of the native tooth‐gingiva interface, but details are still vague. The connective tissue interface with the titanium appears to be one of tightly fitting tissues rather than adhesion. Ceramic coatings appear to improve the ingrowth of bone and promote chemical integration of the implant with the bone. The characteristics of these coatings are complex and affect the bony response, but the mechanisms remain obscure. The degradation of the coatings is an issue of particular controversy. Progress in dental implantology is likely to continue as the interface between the material and bone is more clearly understood, and biological molecules and artificial tissues are developed.
The effect of notch shape and self‐cured acrylic resin repair on the fatigue resistance of an acrylic resin denture base
Authors: Vallittu P. K. , Lassila V. P. , Lappalaine R.
Published: May 2007

summary
This study compares four different notch shapes made on the anterior margin of the palatal plates of heat‐cured acrylic resin test specimens as well as the effect of self‐cured acrylic resin repair on the fatigue resistance of dentures. The test specimens had the shape of an upper partial denture (n = 25). The fatigue test applied was a constant‐force fatigue test at a force of 150 N. The stress concentrations during loading the replicas of the test specimens were determined in the field of a circular polarized light. The results showed that the fatigue resistance of the test specimens decreased dramatically (P = 0–002) when there was a notch at the anterior margin of the palatal plate in the test specimen. A 90° notch decreased the fatigue resistance most effectively. The test specimens repaired with self‐cured acrylic resin were also weaker than the original unnotched test specimens. Examination of the replicas in the field of polarized light showed that stresses occurred only very close to the notch. The highest stress concentrations were detected in the test specimen with a 90° notch, i.e. the test specimens with the lowest fatigue resistance. The results of this study suggest that the shape of the anterior margin of the palatal plate in the acrylic resin‐based partial denture plays an important role in the fatigue resistance of the dentures.
Synthesis of fluorinated Bis‐GMA and its use with other fluorinated monomers to formulate hydrophobic composites
Authors: LI T. , CRAIG R.G.
Published: May 2007

summary
Fluorinated Bis‐GMA was synthesized and used with other commercially available fluorinated monomers and diluents to prepare hydrophobic composites. The composites were formulated as one‐paste systems and were polymerized using blue light. Mechanical properties and water‐related qualities were determined. Fluorination generally improved the hydrophobicity of the composites, but there was no clear‐cut effect on mechanical properties.
The evaluation of post‐retained crowns using a custom designed fatigue machine
Authors: ORR J.F. , MITCHELL C.A.
Published: May 2007

summary
There are many published reports of static tests on dental materials that are required to perform clinically under a range of load amplitudes and cyclic frequencies. There are fewer reports in the dental literature of fatigue tests on dental structures and materials, and these are reviewed in this paper along with a description of the design, manufacture and commissioning of a machine which can apply chosen cyclic load/time characteristics up to a maximum amplitude of 700 N and frequency of 5 Hz. The machine design is not specific to particular test specimens but is widely applicable within dental materials testing. The machine is being used for a continuing study of post‐retained crowns, cemented with glass‐ionomer cement. The planning of fatigue tests and the interpretation of results is discussed with reference to the experience of previous authors, and it is concluded that a survival analysis approach offers a means of understanding materials’ performances. The initial results from a random, blocked comparison of three glass‐ionomer luting cements indicated that cyclic loads can be identified to give a 50% survival probability for specimens. It is expected that loads experienced in vivo have lower amplitude than those applied in this study, however, such loading cycles have been chosen to facilitate material comparisons. It is concluded that gaining significant results under laboratory fatigue conditions is difficult, but that they may usefully complement clinical trials.
Two distinct pathways of tumorigenesis of adenocarcinomas of the esophagogastric junction, related or unrelated to intestinal metaplasia
Authors: Nunobe Souya , Nakanishi Yukihiro , Taniguchi Hirokazu , Sasako Mitsuru , Sano Takeshi , Kato Hoichi , Yamagishi Hisakazu , Sekine Shigeki , Shimoda Tadakazu
Published: May 2007

It is still uncertain whether intestinal metaplasia (IM) of the esophagogastric junction (EGJ) plays a role in the development of adenocarcinoma of the esophagogastric junction (AEGJ). The purpose of the present study was to clarify the relationship between AEGJ and IM in Japanese patients. Forty‐eight AEGJ, <3 cm and centered within 1 cm of the EGJ, were investigated. The frequency of IM around AEGJ and the correlation between IM and clinicopathological features were examined. IM was present in the surrounding mucosa in 22 of 48 cases (46%), and was seen more frequently in older patients (P = 0.008). Lymph node metastasis was observed only in cases in which the tumors were not associated with IM (P = 0.017). The gastric phenotype was seen almost exclusively in the group without IM, while the intestinal phenotype was predominant in the group with IM (P = 0.003). The present study found a lower incidence of associated IM than Western studies, and there were significant differences in clinicopathological features between AEGJ with and without IM. It is suggested that AEGJ may develop via two distinct pathways in Japanese patients: IM‐related and IM‐unrelated.
Association of p16INK4A hypermethylation with hepatitis B virus X protein expression in the early stage of HBV‐associated hepatocarcinogenesis
Authors: Zhu Rong , Li Bai‐Zhou , Li Hua , Ling Yu‐Qin , Hu Xi‐Qi , Zhai Wei‐Rong , Zhu Hong‐Guang
Published: May 2007

The aim of the present study was to explore the relationship between methylation status of the p16INK4A promoter and some HBV‐related factors, and the role of these factors in p16INK4A hypermethylation and hepatocellular carcinoma (HCC) progression. Twenty‐three cases of surgically resected HBV‐associated HCC and 25 fine‐needle aspiration biopsy cases of chronic hepatitis B (CHB) were studied. The methylation status of the p16INK4A promoter was determined by methylation‐specific polymerase chain reaction (PCR). Two‐step immunohistochemical staining showed the expression of viral antigens in situ. Tissue HBV‐DNA levels were determined by fluorescence quantitative real‐time PCR. PCR and the direct sequencing method were used for mutation analysis. In peritumoral tissues (P = 0.025) and CHB samples (P = 0.029), the expression of hepatitis B virus X protein (HBx) was higher in methylated groups of p16INK4A promoter than in unmethylated groups. Other HBV factors including hepatitis B surface antigen and hepatitis B core antigen, tissue HBV‐DNA levels and HBV x gene mutations had no relation to the methylation status of p16INK4A promoter. The data indicate that p16INK4A promoter hypermethylation correlated closely with higher HBx expression in the precancerous lesions, suggesting that HBx may play an important role in the early stage of HBV‐associated hepatocarcinogenesis via induction of hypermethylation of p16INK4A promoter.
Distribution of nestin and other stem cell‐related molecules in developing and diseased human spinal cord
Authors: Sakakibara Ayako , Aoki Eiko , Hashizume Yoshio , Mori Naoyoshi , Nakayama Atsuo
Published: May 2007

In mammalian spinal cords, no neurogenesis has been observed after initial development. However developed mammalian spinal cords seemingly contain neural stem cells (NSC), which can give rise to neurons and glial cells when they are placed in appropriate environments. The purpose of the present paper was to investigate the developing, developed, and diseased human spinal cord to see which cell types have an immunophenotype similar to NSC. In 12 specimens from preterm neonates and term infants up to 14 months old, nestin was expressed in cells that extended fibrous processes and were located around the midline in the ependymal layer. In all the preterm neonates, Musashi‐1 and glial fibrillary acidic protein (GFAP) were also expressed in this subpopulation, whereas Lewis X was detected in a less restricted subpopulation. Nestin expression by these cells was not detected in most adult spinal cords, but was observed in three spinal cords from 13 amyotrophic lateral sclerosis patients and eight of 14 spinal cords involved by the tumor. The present observations suggest that during gestation a subpopulation of cells in the ependymal layer remains undifferentiated as potential NSC/neural progenitor cells, and becomes unidentifiable in early infancy. These cells, however, appear in response to disease conditions, especially tumor involvement.
Thai Trade Policy: From Non‐discriminatory Liberalisation to FTAs
Authors: Sally Razeen
Published: May 2007

FTAs have dominated Thai trade policy recently, reflecting the general trend in east Asia. But they also reflect domestic political changes, especially the decision‐making style of the Thaksin government. Thai FTAs have become very politicised. In particular, the US‐Thai FTA negotiations have run into a storm of domestic protest. The first section of the paper surveys the national trade‐policy framework. It highlights the slowdown of unilateral trade and FDI liberalisation after the Asian crisis, though a descent back into protectionism was successfully resisted. Thailand punches well below its weight in the WTO, and not very forcefully in ASEAN, because political attention and negotiating resources have switched to FTAs. The second section identifies the main actors in Thai trade policy, and briefly describes the trade‐policy decision‐making process as well as recent developments during the Thaksin administration. The following central section deals with Thailand's FTAs. These have been driven by vague foreign‐policy goals, while credible economic strategy has been lacking. The residual commercial logic is narrowly mercantilist and ‘trade‐light’, seeking an exchange of concessions in a narrow range of sectors rather than comprehensive, trade‐creating FTAs. Weak and partial FTAs are the result. The sole exception has been the Thailand‐USA FTA negotiations, as the USA wants a strong, deep‐integration FTA. However, negotiations were suspended in 2006 in the wake of the Thai political crisis. Overall, Thai trade policy post‐Asian crisis is highly unbalanced. It stands on a shaky FTA leg, while the other WTO leg has gone to sleep and the ASEAN arm is limp. Above all, core unilateral liberalisation and related regulatory reform are lacking.
Efficacy of lisinopril in migraine prophylaxis – an open label study
Authors: Schuh‐Hofer S. , Flach U. , Meisel A. , Israel H. , Reuter U. , Arnold G.
Published: May 2007

The ACE‐inhibitor lisinopril has previously been shown to be effective in migraine prophylaxis at a daily dose of 20 mg. To test the effect of a low dose of lisinopril (5 mg daily) in migraine prevention, we performed an open label study in 21 migraineurs. The primary outcome measure was frequency of migraine attacks. Secondary efficacy measures were migraine hours, intake of acute migraine drugs, pain intensity and responder rate. Compared with baseline conditions, the attack frequency of migraine attacks was significantly reduced (P < 0.0005). The number of acute migraine drugs dropped significantly (P = 0.002). Three patients dropped out because of intolerable cough. Our study suggests that even low doses of lisinopril may be effective in migraine treatment. However, its use may be limited by intolerable side‐effects.
Myasthenia gravis patients with ryanodine receptor antibodies have distinctive clinical features
Authors: Romi F. , Aarli J. A. , Gilhus N. E.
Published: May 2007

Myasthenia gravis (MG) is an autoimmune disease caused in 85% of the patients by acetylcholine receptor (AChR) antibodies. Non‐AChR muscle antibodies, against titin and ryanodine receptor (RyR) are mainly found in sera of patients with thymoma or late‐onset MG. The occurrence of RyR antibodies increases the risk for severe MG and should lead to active immunomodulating treatment already at MG onset. The aim in this study was to describe the association between symptoms at MG onset and antibody profile in 152 patients. Patients with RyR antibodies had the highest rate of bulbar, respiratory and neck involvement at MG onset. They also had the highest frequency of non‐limb MG symptoms. Neck weakness occurred in 40%. Respiratory difficulties at MG onset occurred in patients with titin antibodies, with and without RyR antibodies. Patients with RyR antibodies have a distinctive non‐limb MG symptom profile, with bulbar, ocular, neck, and respiratory symptoms. These features, identified as early as at the first examination by a neurologist, characterize the RyR antibody positive subgroup at MG onset.
Polymorphisms at codons 129 and 219 of the prion protein gene (PRNP) are not associated with sporadic Alzheimer's disease in the Korean population
Authors: Jeong B.‐H. , Lee K.‐H. , Jeong Y.‐E. , Hwang K.‐A. , Lee Y.‐J. , Carp R. I. , Ju Y.‐R. , Kim Y.‐S.
Published: May 2007

Polymorphisms of prion protein gene (PRNP) at codons 129 and 219 play an important role in the susceptibility to Creutzfeldt‐Jakob disease (CJD). Alzheimer's disease (AD) and prion diseases, such as CJD, are both characterized by the accumulation of abnormally folded proteins in the brain. An association between sporadic AD and the PRNP polymorphism at codon 129 has been reported in several studies, but other studies have failed to confirm an association. To investigate whether PRNP polymorphisms are associated with an increased risk for developing sporadic AD in the Korean population, we compared the genotype, allele, and haplotype frequencies of PRNP polymorphisms in 271 sporadic AD patients with those in 236 healthy Koreans. Our study does not show a significant difference in PRNP genotype, allele, and haplotype frequency at codons 129 and 219 between sporadic AD and normal controls. Analyses stratifying by age at disease onset, and gender also failed to reveal any association between these polymorphisms and sporadic AD. These results indicate that these PRNP polymorphisms have no direct influence on the susceptibility to sporadic AD in the Korean population.
Reduction of optic nerve fiber layer thickness in CADASIL
Authors: Parisi V. , Pierelli F. , Coppola G. , Restuccia R. , Ferrazzoli D. , Scassa C. , Bianco F. , Parisi L. , Fattapposta F.
Published: May 2007

Our study aims to assess nerve fiber layer (NFL) thickness in patients affected by cerebral autosomal dominant arteriopathy with subcortical infarcts and leucoencephalopathy (CADASIL). Six CADASIL patients (mean age 42 ± 16 years, best corrected visual acuity >20/20 with refractive error between ±3 diopters, intraocular pressure <18 mmHg) were enrolled. They were compared with 16 age‐matched controls. In all subjects enrolled, NFL thickness was measured by optical coherence tomography (OCT). Three different measurements were taken in each quadrant (superior, inferior, nasal, and temporal) and averaged. The data from all quadrants (12 values averaged) were identified as NFL overall. In CADASIL eyes there was a reduction of NFL thickness in each quadrant and in the NFL overall evaluation compared with the values observed in control eyes. Our results suggest that in CADASIL patients there is a reduction of NFL thickness evaluated by OCT. This morphological abnormality could be ascribed to an impairment of the retinal vascular supply leading to a global neuroretinal involvement. These anatomical changes may precede the onset of the neurological clinical manifestations.
Association study of a functional variant in intron 8 of the dopamine transporter gene and migraine susceptibility
Authors: McCallum L. K. , Fernandez F. , Quinlan S. , Macartney D. P. , Lea R. A. , Griffiths L. R.
Published: May 2007

Migraine is a common, genetically influenced neurovascular disorder. The dopamine transporter gene is a candidate for migraine association studies. This study tested a functionally linked variable number tandem repeat (VNTR) in intron 8 of the dopamine transporter gene (DATInt8) in 550 migraine cases (401 with aura, 149 without aura) and 550 non‐migraine controls. Chi‐squared analysis of the DATInt8 revealed that the allele and genotype frequency distributions for migraine cases (including subtype analysis) and controls were not different (P > 0.1). These findings offer no evidence for an association of the DATInt8 with migraine with and without aura and therefore do not implicate the dopamine transporter gene as a modifier of migraine risk.
Paresthesia as a favorable predictor of migraine prophylaxis using topiramate
Authors: Lee S.‐T. , Chu K. , Park J.‐E. , Park H.‐J. , Park J.‐H. , Lee S.‐H. , Kim M.
Published: May 2007

Migraineurs treated with topiramate often experience adverse effects, such as paresthesia, fatigue, memory difficulty, or taste perversion. To investigate correlations between side effects and drug efficacy, we analyzed for these in 133 migraineurs treated with topiramate (100 mg/day). A 4‐week baseline screening phase preceded a 4‐week titration period and a 20‐week maintenance phase. A total of 118 patients were evaluated at 3 months and 89 patients at 6 months. Patients who developed paresthesia (n = 73) showed lower headache days than those who did not (n = 60) (P = 0.026 at 3 months, P = 0.002 at 6 months), and had a higher responder rate (3 months, 57.5% and 6 months, 65.8%) than those who did not develop paresthesia (3 months, 38.3% and 6 months, 41.7%). Moreover, retrospective analysis of patients that dropped out showed no survival bias between paresthesia and headache improvement. Other adverse effects were not found to correlate with drug efficacy. This study suggests that the development of paresthesia predicts a favorable response to topiramate in migraine prophylaxis.
Timing of stenting of symptomatic carotid stenosis is predictive of 30‐day outcome
Authors: Topakian R. , Strasak A. M. , Sonnberger M. , Haring H.‐P. , Nussbaumer K. , Trenkler J. , Aichner F. T.
Published: May 2007

For patients with symptomatic carotid stenosis, benefit from carotid artery stenting (CAS) highly depends on the 30‐day stroke and death rates. Identification of predictors of unfavourable outcome would help guide the patient selection. We analysed the influence of clinical and angiographic factors on the 30‐day outcomes of 77 consecutive patients who underwent CAS for ≥60% symptomatic carotid stenosis within 180 days of transient ischaemic attack or moderate stroke (modified Rankin Scale score ≤3). The 30‐day composite end‐point for stroke (7.8%) and death of any cause (1.3%) was 9.1%. Patients with complicated CAS were older than patients with uncomplicated CAS (mean age 75.1 ± 8.2 vs. 65.9 ± 9.5 years, P = 0.015) and underwent stenting significantly earlier after the qualifying event: median delay 1.5 weeks (range: 0.2–3.0) vs. 3.2 weeks (range: 0.5–26), P = 0.004. In multivariate logistic regression analyses, age [odds ratio (OR) = 1.148; 95% confidence interval (CI): 1.011–1.304 and P = 0.033] and delay of treatment <2 weeks (OR = 22.399; 95% CI: 2.245–223.445 and P = 0.008) remained the only variables significantly associated with 30‐day outcome. CAS carries a considerable risk in old patients and when performed early (<2 weeks) after the qualifying event. Future reports should address the timing of CAS.