bluuebunny/crossref_metadata_2025 huggingface dataset:
Impact fracture characteristics of intact and crowned human central incisors
Authors: STOKES A.N. , HOOD J.A.A.
Published: June 2007

Dynamic fracture energies and patterns of fracture in extracted human central incisors were determined for groups of intact controls, groups with Vita Dur N® crowns, Vita Hi Ceram® crowns, Dicor® crowns and porcelain veneers. Teeth were struck on their middle labial surfaces by a pendulum impact device.

The mean fracture energy for teeth with Dicor crowns was significantly lower than for all other groups (P<0.05). Control tooth crowns fractured obliquely in an apicaldirection. Vita Dur N® and Dicor® crowns, shattered, the underlying tooth usually fracturing in the plane of the impact force. Vita Hi Ceram® crowns chipped at the site of impact and some fractures were located in the roots. Gold crowns remained cemented and fracture occurred at the crown/root junction, or in the root. Porcelain veneers fractured at the site of impact but remained cemented. Dicor® crowns were less fracture resistant than other restoration types tested. Porcelain veneers and full gold crowns stiffened teeth which led to more root fractures than the porcelain crowns.
The ratio between vertical and horizontal changes of impressions
Authors: LEWINSTEIN I.
Published: June 2007

The purpose of this study was to analyze theoretically and experimentally the relations between the horizontal and the vertical changes of impressions taken with a mandibular stock tray. According to the theoretical analysis the ratio between the horizontal (ΔX) and the vertical changes (ΔX) can be expressed as:
image
where μ is the Poisson's ratio and Lx and Lz are the horizontal and vertical dimensions of the die, respectively. With regard to the experimental findings the Poisson's ratio calculated by this expression was μ=0.44 which fits the range of Poisson's ratio for rubber materials. In addition it was shown that the ratio between the vertical and horizontal strains is constant for a particular impression technique.
Knowledge‐based design of removable partial dentures using direct manipulation and critiquing
Authors: HAMMOND P. , DAVENPORT J.C. , POTTS A.J.C.
Published: June 2007

A knowledge‐based system for designing removable partial dentures is described in which graphical representations of denture components are manipulated directly by the user to build the required denture design. The arch form of individual patients may be depicted by linear movement and rotation of the icons representing teeth. The size, shape and position of many denture components are determined dynamically to conform to the shape of abutment teeth and to the juxtaposition of other elements. Expert clinical knowledge is used to analyse the developing design and suggest alternate approaches.
Dual‐cure luting composites. Part I: filler particle distribution
Authors: INOKOSHI S. , WILLEMS G. , VAN MEERBEEK B. , LAMBRECHTS P. , BRAEM M. , VANHERLE G.
Published: June 2007

Fourteen dual‐cure luting composites were analyzed for their filler particle shape, predominant and maximum filler size, and filler weight in function of their clinical use. Polished surfaces were etched with an argon ion beam and studied by means of scanning electron microscopy.

The type of filler particles, either inorganic or prepolymerized, could clearly be recognized. Their shapes were angular, rounded or spherical, depending on the product. The maximum filler size varied extremely from less than 1 urn to 250 urn. A particle‐size distribution analyser disclosed a bell‐shaped filler‐size distribution. The predominant filler size for all the products was much smaller than the maximum filler size. The filler weight varied from 36 to 77%. After ion etching, some products showed small areas with a low degree of filler loading. A classification of the luting composites based on the maximum filler size is proposed. Since the particle size varies widely within the group of products analyzed, a standard specification for luting composites is urgently needed.
Parameters of tooth mobility in cases of normal function and functional disorders of the masticatory system
Authors: NIEDERMEIER W.
Published: June 2007

Tooth mobility was measured mechano‐electronically with the aid of quasi‐static and dynamic methods in 309 patients comprising 2650 teeth being periodontally healthy. Besides, clinical and roentgenographic findings were ascertained to relate functional features to each periodontium. In general the result was that teeth loaded excessively show increased mobility parameters compared to those loaded normally. However, the mobility of teeth loaded poorly or deficiently was even greater compared to teeth stressed excessively. Moreover, follow‐up studies showed that tooth mobility decreases after removal of functional disorders of the masticatory system or an immobilisation of splinted teeth. An experimental trauma of the periodontal ligament also brings on an increased tooth mobility which decreases to the original values some days after the trial.
A method for the estimation of traces of chlorhexidine in water
Authors: WILSON S.J. , WILSON H.J.
Published: June 2007

A simple method of estimating traces of chlorhexidine in water using bromothymol blue is described. The procedure involves the extraction of the chlorhexidine/bromothymol blue complex into carbon tetrachloride from a buffered neutral solution and measurement of the absorbances of the extracts in a spectrophotometer.

The extracted complex has good colour stability, and the method is accurate, reproducible, and very sensitive, with concentrations of chlorhexidine down to 0.05 μg ml‐1 measurable.
Longitudinal study on occlusal force distribution in lower distal‐extension removable partial dentures with conus crown telescopic system
Authors: OGATA K. , ISHII A. , SHIMIZU K. , WATANABE N.
Published: June 2007

The purpose of this study was to examine longitudinal changes of the occlusal force distribution in lower distal‐extension removable partial dentures with the conus crown telescopic system. Occlusal force applied to the denture and forces transmitted to the retainers were measured on several separate occasions from the insertion of new dentures to about 3 months after. The occlusal force distribution ratio to the retainers was calculated when a load of 20N was applied to the denture.

The results are summarized as follows:

 The more posterior the loading point of occlusal force, the smaller was the ratio. When the occlusal force was applied to the most anterior artificial tooth, the ratio was 65‐100% of the occlusal force.

 As the denture wearing time proceeded, the ratio was decreased. The smaller the ratio, the greater was the rate of its decrease.
Comparison of the prevalence, severity and possible causes of occlusal tooth wear in two young adult populations
Authors: JOHANSSON A. , OMAR R. , FAREED K. , HARALDSON T. , KILIARIDIS S. , CARLSSON G.E.
Published: June 2007

Most reports of the prevalence and severity of tooth wear in contemporary Western populations claim that advanced wear is uncommon by comparison with certain non‐Western populations. Differing methods of wear evaluation in the various studies, however, preclude accurate comparisons from being made. This study records mean total and segmental wear indices obtained from the casts of a selected Swedish patient population sample, and age‐ and sex‐matched Saudi high‐wear and random samples. The wear experience of the Saudi random sample compared favourably with that of the Swedish selected one, while the wear of the Saudi high‐wear sample was significantly higher than that of the Swedish sample (P<0.01). The findings from a questionnaire revealed certain significant correlations between aetiological factors and wear, most notably, the relatively greater presence of bruxism (P<0.01), absence of biting habits and minimal cola consumption (P<0.01) in the Swedish sample. Harsh environmental and climatic conditions probably account for the Saudi experience of high wear.
A 4‐year clinical evaluation of extensive amalgam restorations — description of the failures
Authors: PLASMANS P.J.J.M. , VAN 'T HOF M.A.
Published: June 2007

The 4‐year evaluation of a randomized controlled clinical trial to the functioning of Extensive Amalgam Restorations (EAR) is reported. In this trial 300 EAR were made by three operators on molar teeth. Five different auxiliary retention methods were used to retain these restorations. In the evaluation a differentiation in ‘absolute’ and ‘relative’ failures was made. After 4 years seven absolute failures (EAR dislodged or removed) were encountered (2%). When relative failures (endodontic treatment or restoration at margin) are also taken into account the number of failures increased to 31 (10%). Due to the low number of failures, no significant influences from experimental variables (c.q. retention method or operator) could be detected. It may be concluded that the results of this interim analysis of the clinical functioning of EAR are promising. It is thought that careful evaluation of cusp strength and reducing weak cusps diminishes clinical failure and as a result, it is not necessary to protect an EAR with a cast restoration in the first 4 years of its clinical life.
Effects of post‐curing by heat on the mechanical properties of visible‐light cured inlay composites
Authors: KHAN A.M. , SATOU N. , SHINTANI H. , TAIRA M. , WAKASA K. , YAMAKI M.
Published: June 2007

The aim of this study was to evaluate the effects of post‐curing by heat on the mechanical properties of visible‐light (V‐L) cured three inlay composites and three posterior filling composites. One group was only photo‐cured according to the manufacturers' recommended methods, while the other group was heat‐treated at 100°C for 15 min following initial cure by V‐L. Knoop hardness, diametral tensile strength and compressive strength were measured to evaluate the mechanical properties. Cure performance was checked out by the solvent immersion test. Upon secondary‐curing by heat, it was confirmed that the mechanical properties of the composites were increased moderately and the cure performance of the composites was also improved.
Processing dentures using a microwave technique
Authors: ILBAY S.G. , GÜVENER S. , ALKUMRU H. N.
Published: June 2007

In this research the technique of curing denture base acrylic resins by microwave energy was investigated with respect to polymerization method, hardness, mechanical and physical properties. Twenty‐one different polymerization methods were used by varying radiation power and curing time. The Vickers hardness test was applied to the samples which were polymerized. The average value was found to be 22.46 VHN (Vicker hardness number), that is, almost the same as conventionally cured acrylic. The recommended polymerization method of curing acrylic was 3min at 550 W in a microwave oven. Mechanical and physical tests were applied to the samples which were cured by the recommended polymerization method. The average transverse load to fracture value was found to be 7.6 kg, and the transverse deflection value was 1.5 mm at 3500g, and 2.9mm at 5000g. Water sorption of acrylic resin cured by microwave energy was 0.72mg cm−2 and the solubility rate in water was 0.038 mg cm−2. Results conformed with the ADA specification.

The findings showed that acrylic resin cured by microwave energy is more resistant to mechanical failure than conventionally cured acrylic and this technique can safely be applied to the production of denture bases.
Occlusion and craniomandibular function among patients treated with removable partial dentures
Authors: MÄHÖNEN K.T. , VIRTANEN K.K.
Published: June 2007

Forty patients treated with removable partial dentures (RPDs) at the Institute of Dentistry, University of Oulu, were selected for this study. The type of occlusion, horizontal and vertical overlap, the slide between retruded contact position and intercuspal position, and the occlusal interferences were investigated as occlusal parameters. Helkimo's anamnestic and clinical indices were used to measure the craniomandibular function and the clinical index score was used to compare the differences between different groups.

The RPD‐generated occlusal interferences seemed to cause most harmful effects in point centric, interference free occlusions, when the damage was directed at the temporomandibular joint. These interferences were most frequently found in the retruded contact position and caused by the RPD teeth.
Objective evaluation for bite plate therapy in patients with myofascial pain dysfunction syndrome
Authors: KOTANI H. , ABEKURA H. , HAMADA T.
Published: June 2007

An electromyographic study of the masseter and anterior temporal muscles together with questioning patients regarding subjective symptoms was performed on 15 patients with myofascial pain dysfunction (MPD) syndrome prior to and during bite plate therapy.

The electromyographic study was evaluated by the slopes of the voltage tension (V/T) curves (calculated as the value of the relative inclination between the integrated electromyram and the biting force). The improvement of subjective symptoms was recognized earlier than the relief of objective symptoms by bite plate therapy. The results confirm that judgement of level of improvement following treatment of MPD syndrome is more appropriate through objective evaluation. Follow‐up recording of the voltage tension can be considered to be an objective indicator for patients with MPD syndrome.
Interexaminer reliability of six orthopaedic tests in diagnostic subgroups of craniomandibular disorders
Authors: LOBBEZOO‐SCHOLTE A.M. , DE WIJER A. , STEENKS M.H. , BOSMAN F.
Published: June 2007

Interexaminer reliability is defined as the degree of consistency among examiners when making observations of the same clinical variable. In the present study, the interexaminer reliability of six orthopaedic tests was determined in a group of 79 patients with signs and/or symptoms of craniomandibular disorders (CMD), subdivided into three subgroups of patients with a mainly myogenous, a mainly arthrogenous, and a combined myogenous and arthrogenous disorder. Multi‐test scores were composed for each test and combinations of tests for the three main symptoms of CMD, viz. pain, joint noises and restriction of movement. Although the orthopaedic tests showed different reliability scores, overall reliability of the determination of these three main symptoms of CMD was satisfactory.

In the subgroups, arthrogenous signs and symptoms could be determined reliably with the set of six tests, whereas the reliability of the tests in determining pain and joint noises in the myogenous group was rather low. It may be concluded that the tests are well suited to evaluate arthrogenous signs and symptoms, but that the clinician should be aware of erroneous results of the tests in evaluating pain of a myogenous origin.
Histological and immunohistochemical studies on the articular cartilage after experimental discectomy of the temporomandibular joint in rabbits
Authors: MIYAKI K. , MURAKAMI K. , SEGAMI N. , IIZUKA T.
Published: June 2007

Total discectomy was performed experimentally in the rabbit temporomandibular joint (TMJ). In order to evaluate the injury and repair of the articular cartilage of the mandibular condyle after discectomy, both histologic and immunohistochemical observations were made. Immunohistochemical observation by using bromodeoxyuridine (BrdU) and its monoclonal antibody in vivo labelling method was used.

The present study demonstrated that the cartilage on the articular surface of the condyle disappeared at 1 week post‐operatively. This defect in the injured articular cartilage was not repaired by the cartilage, but was covered by a fibrous connective tissue at 6 weeks post‐operatively, where the condylar recontouring by the adjacent articular cartilage, and flattening and hyperplasia of the condyle were observed. Thus, the cartilaginous repair following discectomy was characterized by the proliferation of the adjacent cartilage to the injured site and osteoblastic formation in the bone marrow at the exposed subchondral bone.
Temporomandibular joint osteoarthritis: a comparative clinical and tomographic study pre‐ and post‐treatment
Authors: SATO H. , FUJII T. , YAMADA N. , KITAMORI H.
Published: June 2007

Nineteen patients with definite and suspected temporomandibular joint (TMJ) osteoarthritis participated in this study. All patients were treated by dental care including bite plane therapy. By comparing the pre‐treatment clinical symptoms and TMJ tomograms with those post‐treatment, efficacy of the dental treatment applied for these patients has been assessed.

Since TMJ pain and limitation of mouth opening were considerably improved in almost all patients post‐treatment, this suggests that the clinical prognosis of TMJ osteoarthritis can be favourable. On the other hand, radiographic changes post‐treatment were variable. The longitudinal changes found in the TMJ tomograms were classified into four types. The frequency of Type 2 and Type 3, which indicate the occurrence of TMJ remodelling during the observation period, was fairy high (20 TMJs and 14 patients).
Effect of polylactic acid on osteoinduction of demineralized bone: preliminary study of the usefulness of polylactic acid as a carrier of bone morphogenetic protein
Authors: SAITOH H. , TAKATA T. , NIKAI H. , SHINTANI H. , HYON S.‐H. , IKADA Y.
Published: June 2007

To evaluate the usefulness of polylactic acid (PLA), a bioabsorbable and plastic polymer, as a carrier of bone morphogenetic protein (BMP), a preliminary study has been carried out to investigate any negative effect of PLA on osteoinduction of demineralized bone (DB). PLA (10,600mol. wt) was mixed with DB particles (1– 1.5 mm square) prepared from rat femurs and laid subcutaneously on the intercostal muscle of 4‐week‐old Wistar rats. The PLA/DB pellets were harvested at 2, 4, 8 and 24 weeks after the operation, and prepared for light microscopic examination. Histological examination revealed cartilage formation at 2 weeks and new bone formation at 4 weeks. Extensive bone and marrow formation were observed at 24 weeks. PLA was gradually absorbed and completely disappeared at 24 weeks to be replaced by connective tissue. These results demonstrate that PLA does not have a negative influence on the osteoinductive activity and that PLA could well be a promising bioabsorbable carrier of BMP.
Multidimensional evaluation of craniomandibular dysfunction. I: Symptoms and correlates
Authors: DE LEEUW J.R.J. , STEENKS M.H. , ROS W.J.G. , LOBBEZOO‐SCHOLTE A.M. , BOSMAN F. , WINNUBST J.A.M.
Published: June 2007

To standardize clinical history taking, a comprehensive anamnestic questionnaire was developed (Screen). Screen includes questions about (i) pain, (ii) other symptoms of CMD, (iii) correlates of CMD, (iv) psychosocial factors, and (v) general health. Variables discriminating between subgroups of clinical cases and controls were described successively. This study was performed to assess whether subgroups of patients with signs and symptoms of craniomandibular dysfunction (CMD), and a control group of dental patients with and without signs and symptoms of CMD, can be characterized by differential report of signs and symptoms of CMD, as reported in Screen. Results indicate that Screen can be used to discriminate between (i) subgroups of subjects with signs or symptoms of CMD (both clinical cases and controls) and controls without signs or symptoms of CMD; (ii) subgroups of clinical cases and controls with signs and/or symptoms of CMD; and (iii) patients with CMD with mainly a myogenous component and patients with CMD with mainly an arthrogenous component. Differences between patients and controls are interpreted with regard to the correct classification of patients with CMD with mainly a myogenous component and patients with CMD with mainly an arthrogenous component, and with regard to the subjective treatment need for CMD. The results of logistic regression analyses indicate that subsets of items of Screen correctly classified up to 80% of patients with myogenous or arthrogenous CMD. Implications for further research were discussed.
Leaching from glass ionomer cements
Authors: BAPNA M.S. , MUELLER H.J.
Published: June 2007

This study compared the electrical conductivities, pH and leached ion (F−, Ca, Al, Si) concentrations in supernatant liquids obtained from four glassionomer cements, a buffered ionomer cement, a polycarboxylate cement and a zinc phosphate cement, at three different levels of settings. The result indicated that the measured parameters are highest for the unset condition of cements and decreases as the set condition is approached, except for pH, which shows the opposite trend. Two pulp sensitive glassionomer cements, Chem Bond and Ketac Cem showed high Ca : F ratios as well as high Ca and F concentrations. Further, it is suggested that the cytotoxicity of leached F−, Si, Al and Zn at high concentration and at low pH may induce sensitivity in tooth structure.
An assessment of approximal bone height in the posterior segments of 15—16‐year‐old children using bitewing radiographs
Authors: DUMMER P.M.H. , JENKINS S.M. , NEWCOMBE R.G. , ADDY M. , KINGDON A.
Published: June 2007

SUMMARY
The alveolar bone height in a total of 713 15–16‐year‐old children consisting of 364 males and 349 females was assessed using posterior bitewing radiographs. The distance between the alveolar crest (AC) and amelo‐cemental junction (ACJ) on all molar and premolar teeth was determined from magnified images of the radiographs. Analyses of variance models were fitted in order to assess the dependence of the overall ACJ to AC distance on the inter‐subject variables of gender and social class and the intra‐subject variables of site, missing adjacent tooth, condition of the approximal tooth surface, and for mesial surfaces, gingivitis and pocket depth. The overall geometric mean for bone height for the whole population was 0.542mm. The ACJ to AC distance for the vast majority of sites was below 2 mm. Site had a highly significant effect on bone height (P≤ 0.001): ACJ to AC distances were greater in the maxilla compared to the mandible (P≤ 0.001), greater for distal sites compared to mesial (P≤ 0.001) and significantly affected by tooth type (P≤ 0.001). Sites with missing adjacent teeth also had significantly increased distances (P≤ 0.001). The condition of the approximal tooth surface and the presence of pocketing or gingivitis did not have a significant association with bone height. The geometric mean AC to ACJ distance, adjusted for subject, site and social class was 0.577mm for males and 0.506mm for females (P≤ 0.001), but the main effect of social class was not significant.
Angle of mouth opening measurement: realibility of a technique for temporomandibular joint mobility assessment
Authors: DIJKSTRA P.U. , DE BONT L.G.M. , STEGENGA B. , BOERING G.
Published: June 2007

SUMMARY
The maximal interincisal distance added to the vertical overlap is generally used as a measure for temporomandibular joint mobility. However, the length of the mandible also has an influence on this measure. The angle of mouth opening as a measure of temporomandibular joint mobility is independent of the length of the mandible. The aim of the study was to develop a mandibular goniometer to measure the angle of mouth opening and to test its realiability. Ten subjects, two males and eight females (mean age 28.1 years) participated in the study. The measurements were performed during four independent sessions of three measurements each. The results were analysed with ANOVA. Intraobserver variability was found to be 2–0° when the result of all the measurements were analysed, and were found to be 1–2° when the mean value of the sessions were used for analysis. Based on the results of this study it can be concluded that the angle of mouth opening canbe measured reliably.
Influence of alterations in the oral environment on speech production
Authors: ICHIKAWA T. , KOMODA J. , HORIUCHI M. , MATSUMOTO N.
Published: June 2007

SUMMARY
We examined the influence on temporal aspects of three consonants, /k/, /c/ and /s/, of alterations in the oral environment produced by either palatal augmentation or by an increase in the vertical dimension of occlusion. Voice onset time (V.O.T.) for /k/ and /c/ was influenced more than aspiration time by the palatal augmentation. Consonant duration for /s/ was also influenced by palatal augmentation. Significant influence of an increase in vertical dimension on the timing was not recognized. Speech disorder caused by the malformation of palate seems to be more frequent than that caused by vertical dimension. Adaptation to prostheses would seem to be definitely concerned with orosensory feedback.
Vectorial analysis of the equilibrium of forces transmitted to TMJ and Occlusal biteplane splints
Authors: DOS SANTOS J. , DE RIJK W.G.
Published: June 2007

SUMMARY
A mechanical model (link quadrilateral bell crank) is used to demonstrate the equilibrium of normal force vectors transmitted to the masticatory system and maxillary occlusal biteplane splints with different designs. Occlusal contacts were imposed on the proposed models under the action of a masticatory force vector with an arbitrary value of 40 kgf. The consequence of this force action created different responses within the joint and at the level of the dentition. When compared to the intercuspal position in centric occlusion, intra‐oral appliances with either smooth contacting surfaces or indentations, both with increased vertical dimension, forced the mandible to assume an anterior position with a con‐ current increase of joint forces. The bite‐splint that produced the least amount of joint force was the stabilization type with minimal increase of vertical dimension.
Masseter muscle activity and the hypoglossal nerve
Authors: HARA I. , HIRAKAWA T. , HONDA E. , SETO T. , NAKAHARA S.
Published: June 2007

SUMMARY
The effects of severing the hypoglossal nerve and resultant restriction of tongue movement was evaluated for its effect on masticatory jaw movement. Electromyograms of masseter muscles in the feeding rat were recorded 3 days after the nerve severing operation at 1 week intervals. Even after severing the lateral branches of the hypoglossal nerve bilaterally, active‐feeding behaviour continued with mastication slightly impaired. After severing the medical branches bilaterally, feeding behaviour was rarely observed, but where eating did take place mastication was impaired with marked disturbance in the masticatory rhythm.
A study of the microstructure of some dental retention pins and prefabricated root canal posts
Authors: DIONYSOPOULOS P. , SKOLIANOS S. , PAPADOGIANNIS Y.
Published: June 2007

summary
Pins and root canal posts are generally considered indispensible aids in clinical restorative dentistry. To secure the long‐term efficiency of pins and posts, such devices should be of sufficient strength to carry the relevant loads. It is, however, essential that their properties do not decline as a consequence of corrosion, or that corrosion of metallic pins and posts does not cause unfavourable effect in contacting biological tissues. The microstructure of certain commercially available dental retention pins and prefabricated root canal posts has been investigated using optical microscopy and standard metallographic techniques. The specimens were then examined by scanning electron microscope and energy dispersive X‐ray analysis (EDAX). The results indicate differences in microstructure and condition between the types examined. The results also showed the presence of included particles in some pins and posts. These differences and the presence of inclusions may have an important bearing on service life and corrosion resistance.
Conversion of dual cure luting cements
Authors: DARR A.H. , JACOBSEN P.H.
Published: June 2007

summary
This investigation determined the efficiency and rate of cure of polymeric luting agents when cured under manufacturers' instructions with the appropriate visible light source, and under conditions where light was excluded and curing was reliant on the chemical reaction only. Indentation hardness was used as a reflection of conversion. There was a rapid increase in hardness immediately after light curing followed by a steady increase in hardness over the next 24h. The non‐irradiated chemically cured samples exhibited steadily increasing hardness over 24h, but were too soft to test in the initial 30 min. Hardness values were extrapolated to obtain predicted values of flexural strength. Dual curing was more effective than chemical curing alone. The results suggest that the formulation of dual cure materials is a balance between high levels of conversion in all aspects of the restoration and colour instability due to amine degradation. Clinically there may be poorly cured areas in the deeper aspects of a deep cavity.
Oral habits and TMJ dysfunction in facial pain and non‐pain subjects
Authors: MOSS R.A. , LOMBARDO T.W. , VILLAROSA G.A. , SIMKIN L. , HODGSON J.M.
Published: June 2007

summary
Multifactorial theories for facial pain aetiology have been proposed in the past, although little research has been produced to support a multifactorial actiology. The present study assessed self‐rated oral habits over a 7 day period for facial pain and non‐pain subejects with and without a clinical symptom of TMJ dysfunction. The results indicate a significant effect for TMJ dysfunction and teeth clenching and an interaction between TMJ dysfunction and facial pain for biting of the lips and mouth. A significant chi‐square test showed that most non‐pain controls with TMJ dysfunction reported that they never clenched. The results are discussed in terms of support for a multifactorial aetiology in some facial pain patients and the need for future research to delineate subgroups of facial pain and non‐pain sujects.
Vertical asymmetry of the mandibular ramus and condylar heights measured with a new method from dental panoramic radiographs in patients with psoriatic arthritis
Authors: MATTILA M. , KÖNÖNEN M. , MATTILA K.
Published: June 2007

summary
Vertical asymmetry of the mandibular ramus and condylar heights was measured with a new method from dental panoramic radiographs. The study groups consisted of 45 psoriatic arthritis (PA) and 45 control (CO) matched pairs. Vertical asymmetry was calculated with the formulal |(R‐L)/ (R+L)|× 100. Females showed no statistical significant difference in vertical asymmetry between the PA and CO pairs. In males however, vertical asymmetry showed a statistically significant difference between the PA and CO groups among those aged 35–55 years (P=0.008). This group included four men with arthritis mutilans, a severe form of psoriatic arthritis.
Satisfaction with complete immediate dentures and complete immediate overdentures. A 1 year survey
Authors: JONKMAN R.E.G. , VAN WAAS M.A.J. , KALK W.
Published: June 2007

summary
The aim of this study was to evaluate denture satisfaction over a 1 year period after extraction of the last teeth. Seventy‐four patients who required immediate denture therapy in the mandible were randomly treated, (1) with complete immediate dentures (22); (2) with immediate overdentures on two lower canines without attachments (26); or (3) with immediate overdentures on two lower canines provided with Dyna® direct magnetic attachments, inserted on the abutments 9 months after treatment (26). Denture satisfaction was estimated by means of questionnaires, filled out by each patient at certain periods, starting before treatment and ending 1 year after denture in sertion. After 1 year approximately 85% of the patients in the three groups were satisfied with their dentures, had got used to them and could eat well. This phenomenon was constant over the whole first year period. No differences in denture satisfaction were found between the three groups. It can be concluded that although patients who receive immediate complete dentures might experience a lot of discomfort during the first year of edentulousness, they are satisfied, in general, with their dentures independent of the treatment procedure.
Psychological factors related to the prevalence of temporomandibular joint sounds
Authors: SPRUIJT R.J. , WABEKE K.B.
Published: June 2007

summary
This study focuses on the association between psychological factors and TMJ sounds, and the most suitable research design to establish this relation. A traditional research design is simulated to demonstrate how self‐report may bias findings. A refined design is presented to obtain unbiased estimates of the role of psychological variables. In the ‘naïve’ design the importance of psychological variables was overestimated and the role of physiological variables was underestimated. It was concluded that future studies in the aetiology of TMJ clicking should abandon the use of self‐report as a proxy for objective findings. With the refined design it was found that psychological factors play only a minor role in the prevalence of TMJ sounds. Findings do not support speculation about mechanisms that relate psychological factors to the presence of TMJ sounds.
The rate of OH− ion release from lining materials containing calcium hydroxide
Authors: LIBERMAN R. , BEN‐AMAR A. , LUPO N.
Published: June 2007

summary
Four light‐cured calcium hydroxide and three chemically cured resin‐based lining materials were compared for hydoxil ion (OH) release. Results indicated that the chemically cured calcium hydroxide cements were capable of OH− release for a longer period than the light‐cured resin bases. Alkaliner (a chemically cured liner) produced and maintained the highest alkaline environment in the long‐term, whereas calcium fluoride liner and Basic‐L (both resin‐based) showed the lowest values of OH− ion release.
Experimental occlusal interferences. Part IV. Mandibular rotations induced by a pliable interference
Authors: CHRISTENSEN L.V. , RASSOULI N.M.
Published: June 2007

summary
In 12 subjects, a pliable, yet unbreakable, intercuspal interference (aluminium shim onlay splint; uniform height of 0.25 mm) was placed between either the right or left maxillary and mandibular second premolars and first molars. During brief and forceful biting (dynamic chewing stroke of about 20 kg force) the interference emulated a semisoft food bolus, and at the end of biting (subsequent static clenching stroke of about 20 kg force) it emulated a rigid metal interference. During dynamic/static biting, rotational electrognathography measured maximum frontal and horizontal plane torque of the right and left mandibular condyles.

Eleven subjects (92%) showed frontal plane upward rotation (mean of 1.0°) of the condyle contralateral to the interference, and one subject (8%) showed frontal plane upward rotation (0.4°) of the condyle ipsilateral to the interference. Two subjects (17%) showed no horizontal plane rotation; seven subjects (58%) showed backward rotation (mean of 0.4°) of the condyle contralateral to the interference; and three subjects (25%) showed backward rotation (mean of 0.3°) of the condyle ipsilateral to the interference. It is suggested that, in the presence of an occlusal interference, mastication may have both short‐ and long‐term detrimental effects.
The anterior facial triangle: a method of cephalometric appraisal
Authors: SARHAN O.A.
Published: June 2007

summary
The purpose of this study was to introduce a simple cephalometric method to identify individually the possible rotations of the palatal and mandibular planes, using point nasion as a reference, without the need to include the Sella Nasion or Frankfort horizontal planes. Also, using this method, it was possible to detect the antero‐posterior position of subspinale. A random sample of 150 British school children aged 9‐12 years was used. Lateral skull radiographs were taken. The lateral films were traced and digitzed. A mean shape outline ± 1 s.d. for the sample was produced and superimposed on the craniofacial centroid for all the digitized tracings. A facial triangle was established, joining nasion to posterior nasal spine and nasion to the anteroposterior position of the subspinale intersecting the line joining the posterior nasal spine and anterior nasal spine.
Occlusal variables, bruxism and temporomandibular disorders: a clinical and kinesiographic assessment
Authors: TSOLKA P. , WALTER J.D. , WILSON R.F. , PREISKEL H.W.
Published: June 2007

summary
Seventy‐five patients suffering from myofascial pain, headaches and anterior disc displacement were assessed clinically and with a kinesiograph. Twenty‐eight asymptomatic dental staff served as a control group. The prevalence of awareness of bruxism was significantly greater in our TMD patients than the controls. Bruxism patients recorded a higher prevalence of incisor dentine wear suggestive of a forward mandible posture. Class II, Division 1 malocclusions formed a significantly higher proportion of the TMD patient group than the controls. Kinesiographic recordings showed that the vertical and lateral components of movement from postural position to intercuspal were significantly greater in the patient group.
General health factors and denture function in patients with burning mouth syndrome and matched control subjects
Authors: SVENSSON P. , KAABER S.
Published: June 2007

summary
A total of 30 denture‐wearing patients with burning mouth syndrome (BMS) referred to a Pain Clinic Unit and 26 age‐ and sex‐matched control subjects were examined and compared with respect to general health factors and denture function. The study demonstrated a significantly higher frequency of multiple chronic diseases, psychosocial stress factors, and tenderness/pain in masticatory, neck, shoulder, and suprahyoid muscles in patients with BMS. Denture function differed also between the two groups as patients with BMS had significantly less daily use of dentures, reduced tongue space, incorrect placement of occlusal table and increased vertical dimension. Pain interview with the use of the McGill Pain Questionnaire demonstrated that pain in parts of the body other than the oral cavity were reported more frequently and that the intensity of past pain experiences was not rated higher except for pain in the head in patients with BMS. The results suggested a complex interaction between several general health factors, psychosocial stressors and denture dysfunction in order to explain an idiopathic burning pain in the anterior part of the oral cavity. The existence of demonstrable load factors does not seem to support the suggestion that BMS is primarily a psychogenic disorder.
Prevalence of signs and symptoms of craniomandibular disorders and orofacial parafunction in 4‐6‐year‐old African‐American and Caucasian children
Authors: WIDMALM S.E. , CHRISTIANSEN R.L. , GUNN S.M. , HAWLEY L.M.
Published: June 2007

summary
Children, 4‐6 years old, 153 Caucasian and 50 African‐American, from a pre‐school and kindergarten programme in a low income industrial area, who participated in a voluntary oral health examination, were questioned and examined for signs and symptoms of craniomandibular disorders (CMD) and of oral parafunctions. Most of the CMD signs and symptoms were mild. Eight per cent had recurrent (at least 1‐2 times per week) TMJ pain, and 5% had recurrent neck pain, African‐American chil‐ dren more often than Caucasian children (P < 0.05). Seventeen per cent had recurrent headache. Three percent had recurrent earache. Pain or tiredness in the jaws during chewing was reported by 25% of the children, more often by African‐American than by Caucasian children (P < 0.001) and more often by girls than by boys (p < 0.05). Pain at jaw opening occurred in 10% of the children, more often in the African‐American than in the Caucasian group (P < 0.001). Thirteen per cent of the children had problems in opening the mouth. Deviation during opening was observed in 17% and reduced opening in 2%. Reduced lateral movements, locking or luxation were not observed in any child. Palpation pain was found in the lateral TMJ area in 16%, in the posterior TMJ area in 25%, in the temporalis and masseter areas in 10%, and pain for all regions was found more often in the African‐American than in the Caucasian children (P < 0.01). Thirty‐four per cent of the African‐American, and 15% of the Caucasian children admitted to having ear noises (P < 0.01). TMJ sounds, as recorded by auscultation, occured in 48% of the children, more often in the African‐ American than in the Caucasin children (P < 0.001) and more often in girls than in boys (P < 0.05). Bruxism was noted in 31% of the African‐American and in 17% of the Caucasin children (P < 0.05). Thumb sucking was reported in 56% of the children, more in the girls than in the boys (P < 0.01). The habit was still present in 29% of the children. Fifty‐five per cent had the parafunction nail biting. The results of this study showed that mild but distinct signs and symptoms of CMD already occur by the age 4‐6 with slight differences in distribution observed between the sexes and strong differences noted between the African‐American and the Caucasian races.
Stability of dental waxes following repeated heatings
Authors: KOTSIOMITI E. , McCABE J.F.
Published: June 2007

summary
The flow and strength properties of dental waxes were examined following excessive and repeated heatings of the materials. For one product, the flow at 40±0.5°C was reduced by 25.3% following heating above 200°C. A decrease of the elastic modulus at 20±1°C by approximately 66% was observed in some cases after the heating temperature had been increased to 300°C Property variations were related to compsitional changes, which were investigated by infrared spectroscopy nad thermal analysis. Exposure of dental waxes to temperatures higher than 200°C, particularly if it is repeated, may affect the composition and properties, resulting in inferior materials.
Automated optical scanning for rapid sizing of chewed food particles in masticatory tests
Authors: MOWLANA F. , HEATH M.R. , AUGER D.
Published: June 2007

summary
Analysis of the reduction in sizes of particles after chewing has been a standard method for assessing masticatory efficiency for over 40 years, but the sizing of particles with sieves is very time consuming. A rapid simple method of measuring chewed almond particle sizes by an optical scanning method has been developed and is described. The aim of this study is to validate the accuracy, repeatability and speed of the application of an optical scanning system in measuring chewed particles. To determine the accuracy, paper circles were measured and compared with the travelling microscope measurements. The effect of orientation of the images was assessed by measuring three irregular shaped pieces of paper and three different sized pieces of chewed almonds. Measurements were taken singly at 18° increments from 0‐180° orientations with each piece of paper. To assess the repaeatability of measuring chewed particles, the particles from a single masticated almond washed with water and absolute alcohol were spread, separated and measured by the optical scanning system. The samples were then remeasured 10 times. The reproducibility of the method was investigated using three repeated masticatory tests for each subject in a group of 13 young dentate subjects. The speed of spreading the particles and of measurement was assessed. The absolute error range for a mean area of 31 mm2 was 2.85% to 7.32% with a mean of 3.86%. The relative accuracy of measurement was higher for larger particles but in no case was the standard deviation >0.4 mm2. Therepeatability with different spreads of a chewed almond showed each time the particles were spread there was a small difference in sizing. This was again ±0.44mm2 for an average sized particle (CV = 5.4%). The overall spreading, plus the machine time for measuring the total number and sizes of particles >1 mm, plus anaylsis of size distribution could normally be completed within 6 min. It can be concluded that the application of the optical scanning method gives fast and accurated measurement, counting and sizing of chewed particles.
Prevalence of signs and symptoms of temporomandibular disorders in a young male Saudi population
Authors: NOURALLAH H. , JOHANSSON A.
Published: June 2007

SUMMARY
The aim of the present study was to investigate the prevalence of temporomandibular disorders (TMD) in a selected young male Saudi population. The material comprised 105 dental students having a mean age of 23 years within the range of 20–29 years. A functional evaluation of the stomatognathic system was performed using the Helkimo anamnestic and clinical dysfunction index. Almost two‐thirds of the individuals had no sings and symptoms of TMD. Thirty per cent of the individuals reported mild dysfunction (Ai I) and 6% had severe symptoms (Ai II). Thirty—three per cent showed mild clinical signs of dysfunction (Di I) and 3% had signs of moderate dysfunction (Di II). Only 1% exhibited severe clinical signs (Di III). While the individuals represented a non‐Western population, the prevalence of signs and symptoms of temporomandibular disorders compared favourably to that found in Western countries, at least as regards to reported symptoms.
Masseter muscle relaxation rate in volunteers with a myogenous craniomandibular disorder
Authors: LYONS M.F. , BAXENDALE R.H.
Published: June 2007

SUMMARY
Twelve volunteers were investigated to determine their masseter muscle relaxation rate following voluntary contractions. Four of these volunteers were patients diagnosed as having a myogenous craniomandibular disorder. Electromyograms were recorded from the left and right masseter muscles and maximum bite force was recorded in the midline between the incisor teeth. A sustained contraction was maintained at 50% maximum voluntary bite force for 90s, during which there was a brief relaxation every 10s. Recordings were continued for a 3 min recovery period. This sequence was then repeated at 25% of maximum bite force. Median power frequencies were calculated from the power spectra for the first and last 3s of the sustained contractions. Relaxation rates were measured for each brief relaxation during the sustained contraction and for the relaxation from each brief clench during the recovery period. It was found that maximum bite force values were very similar for volunteers in both the patient and control groups. Relaxation rates slowed more and percentage changes in median frequency were greater in the controls than in the patients during the sustained contractions. However, relaxation rates returned to initial levels more quickly in the controls than in the patients.
Adhesive bonding of titanium with a methacrylate–phosphate primer and self‐curing adhesive resins
Authors: TAIRA Y. , MATSUMURA H. , YOSHIDA K. , TANAKA T. , ATSUTA M.
Published: June 2007

SUMMARY
The adhesive bonding of titanium was evaluated with the use of a metal primer and three types of self curing luting agent. The primer contained 10‐methacryloyloxydecyl dihydrogen phosphate (MDP). One luting agent was a composite material that contained the MDP monomer in its liquid part. The other luting agent was based on methyl methacrylate (MMA), initiated with tri‐n‐butylborane derivative (TBB), and contained 4‐methacryloyloxyethyl trimellitate anhydride (4‐META). The MMA‐TBB resin without 4‐META was used for the control. Pure titanium metal specimens were bonded with various combinations. Shear bond strengths were determined after repeated thermocycles in water. Both MDP and 4‐META were effective in bonding titanium. The decrease in bond strength was minimum when the titanium was primed with MDP and then bonded with the TBB‐initiated resins.
Presentation of a new Flexi‐Flange® post system for
Authors: MUSIKANT B.L. , DEUTSCH A.S. , COHEN B.I.
Published: June 2007

SUMMARY
Advantages of a new post design, Flexi‐Flage® are described. It incorporates a split‐shank parallel threaded post with a flange that seats into an occlusal countersunk dentine space. This case report desecribes placement of three Flexi‐Flange posts in a first bicuspid, canine and central incisor. The Flexi‐Flange system was designed to offer high retention of the post in the root, superior distribution of stresses on insertion and under function, and longterm resistance to metal fatigue.