bluuebunny/crossref_metadata_2025_split huggingface dataset:
Initial flow of tissue conditioners — influence of composition and structure on gelation
Authors: MURATA H. , IWANAGA H. , SHIGETO N. , HAMADA T. 
Published: June 2007

The effects of the molecular weight of polymer powders, the ethyl alcohol content of the liquids, the type of plasticizer and the polymer powder/liquid ratio on viscoelastic properties during gelation of tissue conditioners were studied with an oscillating rheometer. The results showed that:

The gelation time decreased exponentially with increases in molecular weight of the polymer powder and with powder/liquid ratio. There were linear relationships between the log of gelation time, and both the molecular weight of the polymer powder and the powder/liquid ratio.
In general, gelation time decreased exponentially with increases in ethyl alcohol content. However, the relationship between the log of the gelation time and ethyl alcohol content fitted a second‐order polynomial.
The type of plasticizer affected gelation time. The order of gelation times was: benzyl benzoate < dibutyl phthalate < butyl phthalyl butyl glycolate.

The initial flow of tissue conditioners could be controlled over a wide range by varying the molecular weight of the polymer powders, the ethyl alcohol content, the powder/liquid ratio and the type of plasticizer.
Longitudinal study on torque transmitted from denture base to an abutment tooth of lower distal‐extension removable partial dentures with conus crown telescopic system
Authors: OGATA K. , WATANABE N. 
Published: June 2007

The purpose of this study was to make a longitudinal analysis of torque transmitted to a direct abutment tooth of a lower distal‐extension removable partial dentures constructed with the conus crown telescopic system. Torque around the vertical and lateral axes of the tooth were measured during chewing of food at the time of insertion of the new dentures to about three months after. The maximal mean value of torque (Max.MT) was calculated from the peak level of all chewing strokes at the minimum of the interocclusal distance. The integration values of torque (I) and time (T) from initiation of chewing to swallowing were obtained, then the average value of torque (Ave.T) was calculated (Ave.T= I/T).The results are summarized as follows: (a) There were no remarkable changes of Max.MT around the both axes; (b) Max.MT around the lateral axis was 7‐47 × 10‐3kgm (mean: 25X10‐3kgm) (1kgm = 9.8Nm) in the downward direction and Ave.T around the lateral axis was 6.14 × 10‐3kgmss‐1 (mean: 10 × 10‐3kgm ss‐1) in the downward direction; (c) There were marked differences of Max.MT and Ave.T around the vertical axis between subjects. Max.MT around the vertical axis was less than 24 × 10‐3 kgm and Ave. T around the vertical axis was less than 6 × 10‐3 kgm ss‐1.
Clinical performance of different post and core systems ‐ results of a pilot study*
Authors: MENTINK A.G.B. , CREUGERS N.H.J. , MEEUWISSEN R. , LEEMPOEL P.J.B. , KÄYSER A.F. 
Published: June 2007

SummaryDuring the period 1974‐1986, 112 post and core build‐ups were inserted in 74 patients. The build‐ups consisted of a metal prefabricated post (Dentatus, Unimetric or Radix) in combination with a composite core. After an average follow‐up period of 7.9 years, 14 failures (12.5%) were noticed. Eight teeth could be rerestored and six teeth had to be extracted. However, when correction was made for teeth with a bad initial prognosis and for extractions not related to the build‐up restoration, eight failures remained caused by failure of the build‐up (7.5%). The Dentatus posts seemed to increase the risk for failure.
A model to describe how ligaments may control symmetrical jaw opening movements in man
Authors: OSBORN J.W. 
Published: June 2007

SummaryA mechanical model of the temporomandibular (TM) joint was converted into a computer program, with a graphic output, which tested the simultaneous effects on symmetrical jaw opening of the following three constraints: 1) the condyle could not move above the articular surface of the temporal bone; 2) the TM ligament and 3) the sphenomandibular (SN) ligament could not be stretched. Cartesian coordinates describing the ligaments and bones of six different skulls were measured and entered into the model. Although the constraints in the model allowed five different types of jaw opening movement, only one of these was physically possible for any given position of the mandible during opening. Each movement changed the geometry of the constraints. The opening movements of the condyle followed those of the hinge and kinematic axes which have been observed in studies of symmetrical jaw opening. Together with the constraint of the articular eminence, the early phase of opening was controlled by the backwardly inclined TM ligament. The late phase of opening was controlled by the forwardly inclined SN ligament. This mechanical explanation for the observed movements of the condyle is consistent with the principle that accessory ligaments have evolved around joints to reduce the need for some neuromuscular controls by replacing them with mechanical controls.
Dual cure luting composites – Part II: Clinically related properties
Authors: VAN MEERBEEK B. , INOKOSHI S. , DAVIDSON C. L. , DE GEE A.J. , LAMBRECHTS P. , BRAEM M. , VANHERLE G. 
Published: June 2007

SummaryThirteen dual cure luting composites were compared in function of film thickness, consistency, and working time by using the American National Standard/American Dental Association (ANS/ADA) specifications for zinc phosphate cement and direct filling resins. The effect of temperature and setting reaction on the film thickness was also evaluated for some representative products.All three clinically related properties varied widely among the products investigated. A strong linear correlation was found between film thickness and consistency. This relation is supported by the temperature dependence of film thickness of dual cure luting composites. Cooling of the material increased the consistency, resulting in a larger film thickness, while heating reduced the film thickness because of the lower consistency. However, one product with a rather short working time at room temperature occasionally exhibited a dramatically enlarged film thickness after heating, probably caused by accelerated chemical polymerization. No correlation emerged between film thickness and maximum filler size or between consistency and filler weight content. Maximum filler size and filler weight content had been measured previously in Part I of this study. Scanning electron microscope (SEM) analysis of the cured film thickness samples revealed that the largest filler particles had been crushed under the heavy load pressure during film thickness measurement. The lack of correlation between consistency and filler weight content can be explained by the multifactorial determination of the consistency.It is concluded that the great diversity in the currently available luting composites makes clear specifications with regard to the optimum composition of luting composites urgently needed. Furthermore, more adequate methods for testing the film thickness of luting composites are also required.
Relationship between craniomandibular dysfunction and malocclusion in white children with and without unpleasant life events
Authors: VANDERAS A.P. 
Published: June 2007

SummaryAn epidemiologic study was conducted to investigate the relationship between craniomandibular dysfunction and malocclusion in 386 children aged 6 to 10 years with and without unpleasant life events.The results showed no statistically significant correlations between each clinical sign and each type of morphologic malocclusion in both groups. The chi‐square test, however, revealed statistically significant correlation between the pain in the temple region and posterior crossbite in the calm group but not in the not calm group. With respect to the functional malocclusion, the chi‐square test showed statistically significant correlations between interferences in the terminal hinge movement and TMJ tenderness and difficulties in opening wide. However, these correlations were found only in the calm group. When the definitional symptoms of craniomandibular dysfunction were aggregated, no statistically significant correlations were found between them and each type of malocclusion in both groups.The results of this study showed that the correlations between malocclusion and craniomandibular dysfunction were inconsistent.
Monitoring of the discrimination threshold for interocclusal thicknesses in rehabilitated edentulous patients
Authors: PRETI G. , GASSINO G. , LOMBARDI M. , MAZZONE P. 
Published: June 2007

SummaryThirty‐seven white Caucasian subjects with unsatisfactory dentures were tested for interocclusal thickness discrimination threshold. New dentures were prepared and the test was repeated on days 1, 4 and 90 (from delivery). Eight patients whose situation was still unsatisfactory were given osseointegrated implant anchored dentures and the test repeated at the same intervals. Results were analysed statistically. Improved denture fit was found to increase interocclusal sensitivity. Decreased sensitivity during follow‐up might indicate the need to check denture fit.
Hyperalgesic change over the craniofacial area following urate crystal injection into the rabbit's temporomandibular joint
Authors: OKUDA‐AKABANE K. 
Published: June 2007

SummaryThe aim of this investigation was to study the characteristics of hyperalgesia and inflammatory change in the craniofacial area following the production of an acute arthritis of the temporomandibular joint (TMJ) in the rabbit. Unilateral arthritis was produced by the injection of monosodium urate (MSU) into the TMJ of the rabbits. Hyperalgesia was evaluated by the reduction in the threshold of the head‐withdrawal response to pressure stimulation, and inflammatory change was determined by the quantitative Evans‐blue test and light‐microscopic examination of histological sections. Several hours after an injection of MSU (0.15, 0.5, 1.5 mg), hyperalgesic changes were observed over not only the MSU‐administered condyle, but also over the ipsilateral masseter muscle and temporal muscle in a dose dependent manner, and lasted for more than 24 h before gradual recovery. The other craniofacial region showed no significant threshold‐reduction. Although a very intense inflammatory sign was found in the region of the MSU‐treated TMJ, a decreased or negative sign was found in the masseter muscle with a very low threshold. Local block of the TMJ using Bupivacaine® suggested that the hyperalgesic change in the masseteric region was partly due to prolonged excitation of TMJ afferents.
Changes in function of the masticatory system from 7 to 10 years of age in relation to articulatory speech disorders
Authors: PAHKALA R. 
Published: June 2007

SummaryThe aim of the present study was to determine changes in function of the masticatory system in children with articulatory speech disorders and in the controls by re‐examining a sample of 287 previously studied children from 7 to 10 years of age. Articulatory speech disorders were diagnosed by the same speech therapist during spontaneous speech and test words using the Remes Articulation Test. Mandibular movement capacity, occlusal interferences, slide between retruded and intercuspal positions, and signs and symptoms of the craniomandibular disorders (CMD) were recorded by a dentist.The follow‐up results showed that mandibular movement capacity increased in almost all individuals, decreasing only in about 10% of cases. However, among children with speech disorders lateral jaw movements decreased in about 30% of subjects. During growth the prevalence of CMD increased while single signs and symptoms fluctuated. Differences between the groups for expression of CMD, mandibular movement capacity and occlusal recordings mainly levelled off. Higher constancy of subjective symptoms and retrusive interferences in children with speech disorders than in the controls supports our previous findings that, in growing individuals, different orofacial dysfunctions seem to be associated with each other.
Masseter and temporalis surface electromyography in patients wearing complete dentures comparing anterior and posterior occlusal concepts — A pilot study
Authors: GRUNERT I. , KOFLER M. , GAUSCH K. , KRONENBERG M. 
Published: June 2007

SummaryThe activity of jaw elevator muscles (masseter and anterior temporal muscle) was studied by surface electromyography in 17 patients wearing complete dentures with anterior‐canine guidance.Baseline electromyography was recorded with the dentures and compared to recordings obtained with two different splints adapted to the upper denture, one providing anterior guidance leading to immediate disclusion of the posterior teeth during any jaw movement, the other providing posterior guidance buccally on the working side and lingually on the non‐working side (bilaterally balanced occlusion).Recordings were obtained during a sequence of different jaw movements: postural position, maximal tooth contact in intercuspal position, protrusive movement of the mandible (under tooth contact) and during lateral excursions, also carried out under tooth contact.Muscle activity was not significantly different as recorded with dentures only versus with the splints providing anterior guidance. However, a significant increase in activity was observed with bilaterally balanced occlusion.The results of this study in edentulous people are similar to those found in patients with natural teeth.
A 6‐year follow‐up study of oral function in shortened dental arches. Part II: Craniomandibular dysfunction and oral comfort*
Authors: WITTER D.J. , DE HAAN A.F.J. , KÄYSER A.F. , VAN ROSSUM G.M.J.M. 
Published: June 2007

SummaryIn this clinical 6‐year follow‐up study subjects with shortened dental arches (SDA, n= 55), characterized by the absence of molar support, are compared with subjects with complete dental arches (CDA, n= 52) with respect to items concerning craniomandibular dysfunction and oral comfort. In addition, a small group of subjects with SDA and removable partial dentures in the lower jaw (SDA + RPD, n=19) is included in this study.Oral comfort is defined using the following criteria: (i) absence of pain and distress, meaning the absence of signs and symptoms of craniomandibular dysfunction; (ii) chewing ability; and (iii) appreciation of the appearance of the dentition in relation to absent posterior teeth. Additionally, complaints about the free‐end RPD are described.It is concluded that: (i) a SDA (consisting of 3–5 occlusal units, OU) is not a risk factor for CMD and is able to provide long‐term sufficient oral comfort; and (ii) free‐end RPD (in the lower jaw) in SDA do not prevent CMD and do not improve oral function in terms of oral comfort.
The influence of gender on the masseter electromyographic jaw‐jerk reflex in young human subjects
Authors: KOSSIONI A.E. , KARKAZIS H.C. 
Published: June 2007

SummaryThe purpose of this study was to investigate the effect of gender on the masseteric jaw‐jerk reflex, evoked in a sample of nine male and nine female young subjects. Electromyographic jaw‐jerk recordings elicited by chin‐taps in the relaxed masseter muscle of the preferred chewing side, were obtained using a computerized recording and analysis system. In both groups, a jaw‐jerk reflex was recorded in 95.56% out of the total number of chin‐taps. The mean latency was significantly shorter in the females (5.75 ms) than in the males (6.14ms, P= 0.0045), while the amplitude of the reflex was significantly higher in the females (P= 0.0005). No significant differences were found in the mean duration between males (6.86ms) and females (6.73ms).It was concluded that sex variation should be taken into consideration in the interpretation of the jaw‐jerk reflex.
Cytotoxicity of components of resins and other dental restorative materials
Authors: WATAHA J.C. , HANKS C.T. , STRAWN S.E. , FAT J.C. 
Published: June 2007

SummaryCytotoxicity testing of dental restorative materials must be viewed as an assessment of hazards, that is the potential of the material to cause pulpal problems. In this context, composites, glass ionomers, amalgams, zinc‐based cements and peroxide bleaching agents are all possible hazards to the pulp. The risks that these materials will cause pulpal toxicity in vivo can be partly estimated by assessing the cytotoxicity of the substances which are released from these materials in vitro and comparing these cytotoxic concentrations with those concentrations that are present in vivo. The resin components of composites, metal ions and hydrogen peroxide, all of which are released from dental restorative materials, have been shown to be cytotoxic in vitro in sufficient concentrations. The potencies of these substances are quite diverse. However, the Cytotoxicity of these substances in usage tests, and therefore the risks of pulpal toxicity, depends on their ability to diffuse through the dentine and accumulate in the pulp.
Permeability of biological and synthetic molecules through dentine
Authors: HANKS C.T. , WATAHA J.C. , PARSELL R.R. , STRAWN S.E. , FAT J.C. 
Published: June 2007

SummaryThe diffusion through dentine by a number of biological and synthetic molecules, including resins and dyes, is reported. In vitro measurements were derived by experiments with a modified ‘split‐chamber device’. Diffusion was found to be indirectly proportional to dentine thickness for all molecules. Permeability of water‐soluble molecules and ethanol‐soluble molecules was proportional to the molecular weights, except for fluorescein, hydrogen peroxide (H2O2) and urethane dimethacrylate. The resin components tested are not soluble enough in an aqueous medium to diffuse through 0.5 mm dentine at sufficient concentrations to cause cytotoxicity to pulpal cells.
Reflections on the Michigan occlusal splint
Authors: RAMFJORD S.P. , ASH MAJOR M. 
Published: June 2007

SummarySpecific features related to the development, design and use of the Michigan splint have been described. Additional benefits from the Michigan splint beyond what can be expected from conventional stabilization splints and bite planes have been suggested. Important aspects of corrections and maintenance care of the Michigan splint have been stressed.
Multidimensional evaluation of craniomandibular dysfunction. II: Pain assessment
Authors: DE LEEUW J.R.J. , ROS W.J.G. , STEENKS M.H. , LOBBEZOO‐SCHOLTE A.M. , BOSMAN F. , WINNUBST J.A.M. 
Published: June 2007

SummaryTo standardize clinical history taking, a comprehensive anamnestic questionnaire was developed (Screen). Screen includes questions about: (i) pain, (ii) other symptoms of craniomandibular dysfuntion (CMD), (iii) correlates of CMD, (iv) pychosocial factors, and (v) general health. The current study focuses on variables in Screen concerning pain reported somewhere in the head, neck and/or shoulders. This study was performed to assess whether subgroups of patients with signs and symptoms of CMD and a control group of dental patients with and without signs and symptoms of CMD can be characterized by differences in areas reported to be painful, in quantitative and qualitative characteristics of pain, and in factors exacerbating pain. Results indicate that several characteristics of pain as measured in Screen can be used to discriminate between: (i) subgroups of subjects with signs and/or symptoms of CMD and controls without signs or symptoms of CMD, (ii) subgroups of clinical cases and controls with signs or symptoms of CMD, and (iii) patients with CMD with mainly a myogenous component and patients with CMD with mainly an arthrogenous component. The results of logistic regression analysis indicate that four adverbs describing pain correctly classified 75% of patients with CMD‐myo and patients with CMD‐arthro. Differences between patients and controls are interpreted with regard to the correct classification of patients with CMD with a mainly myogenous component and patients with CMD with a mainly arthrogenous component and the subjective treatment need for CMD. Implications for further research are discussed.
Thermocycling — the effects upon the compressive strength and abrasion resistance of three composite resins
Authors: CHADWICK R.G. 
Published: June 2007

SummaryThe purpose of this investigation was to examine the effects of thermocycling upon the compressive strength and abrasive wear resistance of three commercial composites Fulfil®, P‐50® and Herculite‐XR®. Specimens of each material were divided into five treatment groups comprising a control, and four different cycling and storage regimes. Tests for compressive strength and wear resistance were carried out. Prior to testing all specimens were stored in distilled water for 1 week. Three groups were stored at a temperature of 37°C and the remaining two at 60°C. Thereafter all groups that were thermocycled were subjected to 750 cycles of a thermocycling regime consisting of the cycle ACAB where A and B represent the fixed temperatures of 37°C and 5°C, and C, depending upon the treatment group, either 50°C or 60°C.One‐way analyses of variance upon the compressive strength and wear factor data following the treatments highlighted significant differences in the mean compressive strength for all materials (Fulfil (P < 0.05), P‐50 and Herculite‐XR (P < 0.01)) and in the wear factor values for only Fulfil and P‐50 (P < 0.001). Surprisingly, thermocycling P‐50 with an upper temperature limit of 50°C had catastrophic consequences upon the measured properties.It is concluded that some of the observed behaviour may have potentially detrimental consequences upon the long‐term clinical durability of the materials tested.
Assessment of chewing efficiency: a comparison of particle size distribution determined using optical scanning and sieving of almonds
Authors: MOWLANA F. , HEATH M.R. , VAN DER BILT A. , VAN DER GLAS H.W. 
Published: June 2007

SummaryParticle sizes obtained with progressive chewing cycles were quantified by use of an optical scanning device and compared with the sieving method. The aim of this study was to validate the optical method by comparison with sieving using a natural test food, almond. Masticatory efficiency was assessed in six dentate subjects. The almonds were chewed for 1, 4, 8, 16 and 32 chewing strokes. Each experiment was replicated. The chewed material was sieved through a 1 mm aperture sieve on a Büchner funnel and dried after washing with water and 100% alcohol. The dried particles were weighed and scanned by an optical scanning device for number and size. The same samples were sieved and weighed with a conventional sieve method. The results of both methods were described by particle size distributions based on the volume of particles. The results derived from the optical scanning and sieving showed similarity. It can be concluded that the optical method is simple to use, faster than sieving and needs little skill in the use of equipment. The comparison of the results validates both methods.