bluuebunny/crossref_metadata_2025 huggingface dataset:
Noise level evaluation of dental handpieces
Authors: MUELLER H. J. , SABRI Z. I. , SUCHAK A. J. , McGILL S. , STANFORD J. W.
Published: June 2007

We evaluated the noise level of fourteen air‐driven handpieces, six low speed (less than 20,000 rev/min) and eight high speed (greater than 160,000 rev/min), with respect to a three‐directional co‐ordinate system and distances of 6, 12 and 18 in. in each chosen direction. A two‐way analysis of variance of the noise level between handpieces and positions indicates that large significant differences exist amongst handpieces and in different positions, and that interaction is just barely significant. The ranking and least significant differences for the mean of all handpieces v. position and for the mean of all positions v. handpiece were compared with the results for the ranking and significances from the one‐way ANOVAS for each handpiece v. position and for each position v. handpiece.

A trend exists with some of the handpieces of straight design (all low speed) for increased noise levels in a direction perpendicular to the handpieces and decreased levels in a direction parallel to the handpieces. For handpieces of angled design (all high speed) both directions parallel and perpendicular (the perpendicular to the longitudinal turbine axis) to the rotor axis indicate increased noise levels. The parallel direction includes the exiting air from the exhaust port. The perpendicular direction can be indicative of an aerodynamic factor associated with the established air flow patterns. The extremes in noise level were 56.8 dBA for a low‐speed handpiece of straight design at the 18 in. distance in a direction parallel to the handpiece, and 87.3 dBA for a high speed handpiece at the 6 in. distance in a perpendicular direction.
Effects of occlusal adjustment on the periodontal condition and on the symptoms of masticatory dysfunction in patients treated with fixed prosthesis–a one‐year follow‐up study
Authors: ETTALA‐YLITALO U.‐M.
Published: June 2007

A total of fifty‐nine patients treated with a fixed prosthesis 4 years previously were recalled for a clinical and radiological examination. The subjects studied consisted of two groups: in group A the teeth of the patients with TMJ symptoms were selectively ground, whereas no grinding was performed in group B.

At the first examination, occlusal interferences were found in 43.0% of the crowns and in 29.0% of pontics in group A before occlusal adjustment. At the second examination 1 year later, the percentage of occlusal interferences was decreased in this group (33.0% of the crowns and 25.8% in the pontics). In group B no changes in occlusal interferences were found after the 1‐year follow‐up period.

The results of the investigation suggested that the frequency of interferences related to occlusal adjustment is important and the effect of occlusal adjustment to periodontal condition and TMJ symptoms is beneficial.
The effect of partial denture design on abutment tooth and saddle movement
Authors: FEINGOLD G. M. , GRANT A. A. , JOHNSON W.
Published: June 2007

A laboratory investigation designed to simulate the effect of loads applied to a free‐end saddle partial denture was carried out. Abutment tooth and also saddle movement were monitored using a photogrammetric method. Loads applied to the denture saddle were transmitted through the occlusal rest and also the clasp components causing movement of both denture saddle and the abutment tooth. The direction of abutment tooth movement was towards the mesial, whether the occlusal rest was situated on the mesial or distal aspect of the tooth crown. It was also evident that the design of the clasp unit used affects the magnitude and direction of abutment tooth movement.
A clinical evaluation of fixed bridges, 10 years following insertion
Authors: KARLSSON S.
Published: June 2007

In this long‐term clinical study, the condition of extensive fixed bridges was investigated 10 years after cementation. From the records of the Swedish Insurance System (Gothenburg branch) the individuals were randomly selected. All restorative treatment had been performed by private general practitioners. The investigation comprised a total of 238 bridges making 1606 units, 944 abutment and 662 pontics. Seven bridges had been removed and in a further nine cases the bridge had been separated and units removed. Loose retainers were detected at thirty (3%) abutments. In 14.5% of the surfaces a deficiency in marginal adaptation was found. An open margin seemed to be the most serious defect and was often related to caries in contact with the margin of the crown. Caries and fillings in relation to the margin were detected in 8.1% of the surfaces. Porcelain bonded to gold restorations were significantly more often overcontoured in the interproximal space compared with acrylic resin veneer gold bridges. In the investigation the caries status has been also thoroughly reported. Abutment teeth, presumed to be vital, had a prevalence of 10% radiographically visible periapical lesions. Finally, 93.3% of the bridges cemented 10 years prior to the investigation were still in function without any parts being removed.
Electromyographic screening of myogenous and arthrogenous TMJ dysfunction patients
Authors: NAEIJE M. , HANSSON T. L.
Published: June 2007

Sixty patients, clinically examined for TMJ dysfunction, were also electromyographically screened. The TMJ dysfunction pain in forty patients was evaluated to be mainly of a myogenous origin and in fourteen patients of a mainly arthrogenous origin. Due to lack of findings in the clinical examination six patients were not to be classified into either of the two groups. They were excluded from the EMG study. For the EMG examination the patients were asked to clench for 30 s in the intercuspal position at 50% of the maximum EMG activity of the masseter muscles. Surface electromyograms of the right and the left masseter and anterior part of the temporalis muscles were monitored. The amplitude of the EMG signal, the duration of the silent period and the changes in the frequency composition of the signal during the 30 s contraction were analysed.

Statistically significant differences between the two patient groups were found in EMG amplitude and in silent period duration. However, the difference in silent period duration was due to the dependency of the silent period on the activation level of the muscle. No statistically significant difference in silent period was found when this dependency was corrected for in the data. The EMG parameters related to muscular fatigue phenomena did not show any difference between the two groups.

The difference in EMG amplitude and consequently the difference in silent period duration support the clinically made distinction into mainly a myogenous or mainly an arthrogenous origin of TMJ dysfunction pain.
The prophylactic reduction of cusps—is it desirable?
Authors: OWEN C. P.
Published: June 2007

In the opinion of some authors cusps are functionally efficient when worn down: others view cusps as efficient structures in themselves which should be retained. Such opinions are reviewed, and some conclusions drawn as to whether cusps should be retained or imitated when restoring an occlusion.
Occlusal force pattern during chewing and biting in dentitions restored with fixed bridges of cross‐arch extension
Authors: LUNDGREN D. , LAURELL L.
Published: June 2007

The pattern of axially directed occlusal forces, i.e. magnitude, distribution, duration and frequency of occlusal forces perpendicular to the occlusal plane, was studied during chewing, swallowing and biting in twelve subjects whose dentitions were periodontally treated and prosthetically restored with fixed, cross‐arch bridges whose periodontal support included bilateral end abutments.

The measuring devices consisted of four strain gauge transducers bilaterally mounted into pontics of maxillary bridges to represent the posterior and anterior regions. The forces could thus be studied in various parts of as well as over the entire dentition simultaneously.

All subjects exhibited a rhythmic chewing pattern with preference of one side as chewing side.
Adaptation of eight modern dental amalgams to walls of Class I cavity preparations
Authors: SYMONS A. L. , WING G. , HEWITT G. H.
Published: June 2007

An in vitro study was conducted in which a range of amalgam alloys was condensed into Class I cavity preparations. The force of condensation and increment size were varied to determine the effect of these operator variables on the adaptation, of the alloys investigated, to the prepared cavity walls. Specimens were sectioned, metallographically polished and examined using light and scanning electron microscopes. For each specimen ten random points on the pulpal and both vertical walls were selected to measure the adaptation of the amalgam to the tooth structure.

For the Class I cavity preparation the adaptation of all alloys to the vertical walls was better than the adaptation to the pulpal walls. The overall adaptabilty of the alloy did not appear to be determined by the particle size, shape or composition. Condensation force was the most important factor in influencing adaptation of amalgam to the cavity walls. Heavy condensation forces produced better adaptation for all alloys particularly when condensing small increments.
Denture identification—a simple approach
Authors: HEATH J. R.
Published: June 2007

In order to find a denture identification method that could be rapidly applied to completed dentures, a variety of spirit pens and commercial and experimental sealants were investigated. The pens were generally rapidly removed by one or more abrasive, denture cleansing, antiseptic or mouthwash agent; the sealants exhibited greater longevity. An experimental sealant (acrylic polymer dissolved in chloroform) was found to be cheap, readily prepared, easily applied, very resistant to abrasion, unaffected by immersion denture cleansers, antiseptics and mouthwashes, to produce no more crazing on dentures than the other sealants investigated, and not to affect the transverse strength of acrylic resin.
The use of computed tomography in the detection of radiolucent denture base material in the chest
Authors: NEWTON J.P. , ABEL R.W. , LLOYD C.H. , YEMM R.
Published: June 2007

With the introduction of acrylic resin denture base materials to the dental profession, radiolucency was recognized as a significant deficiency at an early stage. Continuous research into the production of a radiopaque material has been directed at including radiopaque glasses, salts or metals powders in an otherwise radiolucent polymer. However, the majority of new dentures are still made in radiolucent material which is notoriously difficult to locate by conventional radiography and reports continue to appear relating to the inhalation or ingestion of dentures (or fragments of them), occasionally leading to the death of the patient.

Advances in radiographic techniques and equipment have seen the development of computed tomography (CT). This has proved invaluable as a diagnostic aid for disease and therapy but little attention appears to have been given to the use of this sophisticated technique in the detection of foreign bodies, in particular those of dental origin. This study investigates the use of CT in the detection of radiolucent denture base material. The results suggest that CT has substantial advantages over conventional radiography in the detection of this material and should be considered as a valuable diagnostic aid in those patients thought to have inhaled dentures or fragments of dentures.
A new technique for measuring the radiopacity of natural tooth substance and restorative materials
Authors: WILLIAMS J. A. , BILLINGTON R. W.
Published: June 2007

A technique was developed which utilized a visible‐light spectrophotometer to measure the transmission of light through a radiograph. This was used to compare readings produced by an aluminium step‐wedge and the material of which radiopacity was under investigation. This enabled the radiopacity of the material, be it tooth substance or restorative material, to be measured accurately. The radiopacity, on average, of fresh enamel was found to be 2.1 mm Al/1 mm enamel and that of dentine to be equivalent to 1.0mm Al/1 mm dentine.
Differences between sexes in maximum jaw opening when corrected to body size
Authors: PULLINGER A. G. , LIU SHU‐PAO , LOW G. , TAY D.
Published: June 2007

According to linear interincisal measurements, women have a smaller maximum jaw opening than men. In this study the difference was 2.7%. In contrast, epidemiological surveys indicate that woman have a greater mobility of joints and generally more joint laxity.

Covariate analysis was used to test for the difference between sexes in mean maximum passive opening adjusted according to group mean differences in other parameters of body size. The net result was that the values became more equal between sexes.

A second method, employing a geometric estimation for the angle of maximum jaw opening, showed that women had a 5.4% wider range of jaw opening than men (P<0.057). This method avoided the problem of considering relative body size and body factors which generally correlated poorly with maximum opening. It should be noted that an increased range of opening is a measure of hyperextensibility and does not necessarily imply laxity or instability.
Lateral and anterior–posterior mandibular position discrimination by normal subjects
Authors: WILLIAMS W. N. , LAPOINTE L. L. , FAIRCLOTH B. H.
Published: June 2007

This study examined and compared lateral and anterior‐posterior (A‐P) mandibular position discrimination for a group of twenty normal subjects (mean age=26 years). A specially designed and constructed sliding scale required subjects to position their mandible precisely in the horizontal plane and to try to discriminate differences in the control of their mandibular position. The results revealed that subjects are more sensitive in detecting changes in the lateral positioning of their mandible than in the A‐P positions. Subjects' difference limen (DL) values (threshold of discrimination between two positions) in detecting changes in mandibular position to the right of centre was 1.59 mm, and to left of centre was 1.41 mm. Subjects' DL values obtained with the mandible forward, and back of, the reference position were 1.39 and 2.61 mm respectively.
Periodontal conditions with removable complete and partial dentures in the adult population aged 30 years and over
Authors: MARKKANEN H. , LAPPALAINEN R. , HONKALA E. , TUOMINEN R.
Published: June 2007

The periodontal conditions of subjects with different combinations of removable dentures were studied in a representative sample of 8000 subjects, of which 90% were used for the experiment. The number of subjects with removable dentures was 1468. Subjects with removable partial dentures had significantly more pockets and deeper pockets than did those without dentures. The periodontal condition of subjects with a complete denture in the opposite jaw was significantly better than that in other subjects. This was true in both men and women. The results indicated the importance of prophylactic and maintenance care in subjects with removable partial dentures.
A study of the occlusal plane orientation in complete denture construction
Authors: KARKAZIS H. C. , POLYZOIS G. L.
Published: June 2007

A cephalometric study was conducted on eighteen dentulous subjects and fifty‐six complete denture wearers to determine the location of the natural and artificial occlusal planes as related to Camper's plane. The results indicated that both the natural and artificial occlusal planes were not parallel to Camper's plane. However, the final anteroposterior inclination of the artificial occlusal plane in complete dentures was almost the same as the inclination of the natural occlusal plane.
Functional disturbances of the masticatory system related to temporomandibular joint involvement by rheumatoid arthritis
Authors: ETTALA‐YLITALO U.‐M. , SYRJÄNEN S. , HALONEN P.
Published: June 2007

Several theories have been proposed concerning the aetiology of dysfunction of the temporomandibular joint (TMJ). To analyse the relationship of radiographic changes to clinical signs and symptoms of TMJ dysfunction, the present study was conducted in subjects highly predisposed to TMJ involvement, i.e. in patients with rheumatoid arthritis (RA). The aim of the study was to estimate the frequency of disturbances in the masticatory system of RA patients. In addition, the relationship between TMJ abnormalities and the signs and symptoms of dysfunction was investigated.

The study consisted of sixty patients with RA and forty control subjects. Asymptomatic subjects were more frequent in the RA group than in the controls. Muscle pain during palpation was recorded in 53.3%, clicking in 53.3%, crepitation in 21.7%, reduced movement capacity of the TMJ in 41.7%, and restricted mouth opening in 31.7% of the RA patients examined. In the control group the most common symptoms and signs were clicking (57.5%), muscle pain during palpation (57.5%) and restricted opening (25.0%).

Normal radiographic appearance of the TMJ in RA patients was found in 31.7%. Minor changes comprised 31.7%, moderate changes 21.6%, and severe changes or total loss of the condyle 15.0%. In the control group a normal joint was detected in 87.5%, while minor changes were encountered in 7.5%, and moderate or severe changes only in 5.0%. No relationship was found between Helkimo's anamnestic, clinical or occlusal indices and the severity of the disease graded according the criteria outlined by the American Rheumatism association (ARA). In the ARA group the frequency of signs and symptoms of dysfunction increased with the destructive changes in the TMJ area. In the controls, muscle pain during palpation and clicking sounds in the TMJ were most commonly connected with normal radiographic appearance of the TMJ. In the discriminant analysis the most discriminating factors were crepitation, tenderness to palpation of muscles and movement of TMJ.
Edentulousness—an oral handicap. Patient reactions to treatment with iawbone‐anchored prostheses
Authors: ALBREKTSSON T. , BLOMBERG S. , BRÅNEMARK A. , CARLSSON G. E.
Published: June 2007

A questionnaire was sent to all 189 edentulous patients with denture adaptation problems who were treated with fixed prostheses on osseointegrated oral implants during the period 1965–1978. One hundred and fifty‐two patients (80%) responded. Practically all had adapted well to the prostheses and were most satisfied with the rehabilitated oral function, including chewing ability. Four out of five patients regarded the bridge as part of their own body instead of a foreign object, and 90% would not hesitate to have the treatment performed again, if necessary. Parallel with the improved oral function the patients reported a definite reduction of psychosocial problems associated with their previous oral invalidity, and increased security and self‐esteem.
The use of panoramic radiographs to measure alveolar bone areas
Authors: WILDING R. J. C. , LEVIN I. , PEPPER R.
Published: June 2007

The purpose of the study was to determine the accuracy of measurements made of the mandible from panoramic radiographs. A comparison was made between measurements made directly from dry mandibles, and measurements made from panoramic radiographs of the same mandibles. The use of linear proportions reduced the errors of successive radiographic observations but failed to reveal left‐ and right‐side differences. A method was developed to demarcate two areas of the radiograph, one of which was defined by the crest of the residual alveloar ridge and the other independent of the alveolar ridge. Both areas were measured and their proportions calculated for each mandible observed. This proportional value was referred to as the Area Index. The method was applied to panoramic radiographs of individuals with complete dentitions. The inter‐observation error of the Area Index was found to be 4·9%. It was concluded that, in selected cases, panoramic radiographs can be used to provide information about resorption of the residual mandibular alveloar bone.
Pressures recorded at the denture base–mucosal surface interface in complete denture wearers
Authors: WATSON C. J. , HUGGETT R.
Published: June 2007

This study reports on pressures recorded at the denture base–mucosal surface interface in four edentulous subjects. Four sites were selected, namely (a) the mid‐palatal region in the upper complete denture, (b) the labial to the mid‐line lower complete denture, (c) directly under the lower left and (d) right first molar teeth.

The study examined the reproducibility of the pressure values obtained when the subjects chewed two test foods (carrot and peanut). The subjects repeated the chewing sequences on the same day and one subject was tested over a 3‐day period. The younger subjects and subjects with the shortest chewing sequences gave the most reproducible results. The two foods were shown to have different effects both on the pressure values recorded and the duration of the chewing sequence. Patients who transferred the food bolus from side to side during the chewing sequence affected the reproducibility of the results obtained from the lower denture transducers.
Dental stability and maximal masticatory muscle activity
Authors: JIMÉNEZ I. D.
Published: June 2007

The electromyographical (EMG) activity of masticatory muscles during full clenching in the retruded contact position (RCP) and intercuspal position (IP) with and without a posterior stabilizing splint was studied. The linear envelope EMG signal from three bilateral muscles was recorded (masseter, anterior temporal and posterior temporal). Thirty‐seven subjects were evaluated. Clenching in the RCP without the splint and with the presence of an unstable occlusal contact inhibited the masseter muscle activity and reduced anterior temporal and posterior temporal muscle activity. The masticatory muscle activity returned to normal when clenching in the RCP with a splint that permitted stability in the dentition. EMG activity was the same in the IP with and without the splint.

The results indicate that the determinant of maximal masseter isometric muscle contraction is the amount of stability in the dentition rather than the jaw position. If the dentition takes the major role of stabilizing the mandible, i.e., there is good intercuspation, the masseter muscle can exert maximal isometric contraction. If the stability is not provided by the dentition, i.e., there is a premature contact, the jaw muscles must contribute to the stabilization and reduce the magnitude of the maximal contraction to avoid damage to the structures involved in the compensatory stabilization.
Forces required by complete dentures for penetrating food in simulated function
Authors: EERIKÄINEN E. , KÖNÖNEN M.
Published: June 2007

Forces required by complete dentures for penetrating some commonly used food items were measured experimentally. These forces were compared with the maximal bite forces of twenty‐seven complete denture wearers.

Food items that required the greatest forces in direct closure were rye bread (167 N), raw carrot (118 N), boiled meat (80 N), and raw cabbage (74 N). Raw carrot and raw cabbage required the greatest force in straight incision (39 N and 33 N, respectively). Simulated laterotrusion aided most in the penetration of rye bread and boiled meat. The penetration forces in simulated conditions were high compared with the maximal bite forces of the complete denture wearers.
Chemomechanical caries removal—a clinical evaluation
Authors: ZINCK J. H. , McINNES‐LEDOUX P. , CAPDEBOSCQ C. , WEINBERG R.
Published: June 2007

The aim of this investigation was to evaluate the efficacy and convenience of decayed dentine removal with N‐monochloro‐DL‐2 aminobutyrate (CARIDEX) in all classes of cavities. Fifty‐seven patients, each with two teeth having similarly sized carious cavities, participated in this study. One cavity in each patient was treated with the chemomechanical CARIDEX technique and the other cavity was treated with conventional mechanical drilling. The cavities were restored with either amalgam, composite or glass ionomer restorative materials. The time taken for access and caries removal was noted and the efficacy of caries removal with each technique was evaluated. The chemomechanical caries removal technique was effective in removing 90–100% of decayed dentine in 98% of the cavities treated. Multiple regression adjusted access and caries removal time to account for volume of caries removed. This adjusted time was operator dependent, and ranged from 4 to 10 minutes longer for CARIDEX than for the conventional technique. Ninety‐three per cent of patients preferred the chemomechanical method of caries removal over the conventional technique (highly significant P<0·001). Even though the chemomechanical removal of caries is slower than the conventional technique, the efficacy of CARIDEX and its high patient acceptance provides a viable alternative method for dentinal caries removal in all classes of cavities.
Single‐crystal sapphire endosseous dental implant loaded with functional stress—clinical and histological evaluation of peri‐implant tissues
Authors: HASHIMOTO M. , AKAGAWA Y. , NIKAI H. , TSURU H.
Published: June 2007

Peri‐implant tissues of the single‐crystal sapphire implant connected with neighbouring teeth by a metal bridge‐work were examined clinically, radiographically, and histologically in ten monkeys. Professional tooth cleaning was performed during the study. At 3–12 months after insertion, most of the implants were firmly connected to the surrounding tissues and peri‐implant gingiva was regarded as healthy, based on various periodontal parameter scores. Destructive changes of the peri‐implant bone were not found radiographically. Histologically peri‐implant gingiva was revealed to show similar structure to that of the gingiva around natural teeth. Direct bone‐implant interface was observed at 3 months after insertion, while a thin loose fibrous connective tissue layer was present between bone and implant at 6 and 12 months. Such different interrelationship between bone and implant might be attributable to the difference in distribution of functional stress.
Bilabial compression force discrimination by human subjects
Authors: WILLIAMS W. N. , VAUGHN A. O. , CORNELL C. E.
Published: June 2007

This study examined and compared bilabial compression force difference limen (DL) values (the minimally perceivable difference between two compression forces) for a group of twenty normal‐speaking female subjects (mean age, 25 years) under conditions with and without the teeth clenched. In addition, measures of maximum bilabial compression force under conditions with and without the teeth clenched were obtained. Mean DL values obtained against a standard of 100 gm were 36 gm for the clenched condition and 38 gm with no clenching. Discrimination performance under these two conditions was not significantly different (P>0.05). Mean maximum bilabial compression force was 411 gm with the teeth clenched and 568 gm without clenching. This difference in performance was significant (P<0.01). This study provides initial normal data against which individuals with labial sensorimotor dysfunction can be compared.
A new objective parameter for the electromyographic evaluation of masticatory function of edentulous patients
Authors: NAGASAWA T. , YOSHIDA K. , MINAGI S. , TAMURA H. , TSURU H.
Published: June 2007

An objective parameter for the electromyographic evaluation of the masticatory function of edentulous patients was studied. The normal ranges of the parameters for such subjects were also established.

This study focused on the time parameter of electromyography, which is one of the most reproducible parameters. The variation coefficient of the time parameters (interval and duration) were revealed to be reliable and reproducible for the evaluation of masticatory functions.
Pain in the sternocleidomastoid muscle and occlusal interferences
Authors: KOHNO S. , YOSHIDA K. , KOBAYASHI H.
Published: June 2007

The EMG of the sternocleidomastoid muscle and the masticatory muscles during function has been observed in relation to opposing occlusal contacts. The purpose was to investigate the possible developmental mechanism of pain which can occur in the muscles.

Six subjects with normal function and ten patients were studied. EMG activities of temporal, masseter, sternocleidomastoid (insertion) and sternocleidomastoid (middle) were recorded by surface and needle electrodes.

EMG activity was recorded from the insertion of the sternocleidomastoid during activity of the masticatory muscles in tapping, clenching, and mastication. On the other hand little activity was registered from the middle of the sternocleidomastoid. The amplitude of the EMG of SCM‐I increased as the occlusal force increased. During chewing the sternocleidomastoid muscle was functioning more actively on the working side than on the non‐working side. On the patients, EMG activities of the muscles were of low amplitude and low frequency with no synchronization with the chewing movement, suggesting hyperactivity of the muscle.
Lateral forces exerted on the abutment tooth of complete mandibular overdentures
Authors: OGATA K. , NISHIGAWA G. , AOKI T. , MAEDA Y. , OKUNO Y.
Published: June 2007

The purpose of this study was to analyse the magnitude and direction of lateral forces exerted on the abutment tooth of a complete mandibular overdenture. A newly developed transducer was used for measuring forces. It was small enough to be embedded in the lower denture base, and could detect the magnitude and direction of forces.

Five subjects, 38 to 77 years of age, with an edentulous maxilla and one or two canines remaining in the mandible were selected for this experiment. An upper complete denture and a lower complete overdenture with only one abutment tooth were fabricated for each subject. Forces exerted on the abutment tooth were measured during tapping and chewing of kamaboko (a Japanese cooked fish paste with soft consistency) and also peanuts, a few days and about 20 days after the denture insertion.

The following results were obtained: (i) the average magnitude of lateral forces ranged from 0.5 to 2.0 kgf, and there were significant differences of the mean value between subjects; (ii) lateral forces were mainly observed on an imaginary line drawn through the experimental tooth (lower canine) and the opposite retromolar pad. There were no significant differences between the first and the second measurement.
Dentine hypersensitivity. I. Effects produced by the uptake in vitro of metal ions, fluoride and formaldehyde onto dentine
Authors: ADDY M. , MOSTAFA P.
Published: June 2007

Dentine has been shown to possess affinity for a large number of varied compounds, many of which have been shown effective in clinical trials, for the treatment of dentine hypersensitivity. The mode of action of these compounds is unclear. The aim of this study was to investigate the uptake of metal ions, fluoride and formaldehyde in solution onto dentine in vitro and determine whether therapeutic effects could be mediated through occlusion of dentinal tubules. Etched dentine sections were exposed for 1 h to 1000 ppm solutions of fluoride and metal salts. Levels of fluoride and respective metals could be extracted and measured from the specimens. Saliva pretreatment had a variable but small effect on uptake of each ion, but post treatment washings reduced all levels of retained fluoride and metals. X‐ray micro‐analysis indicated surface or immediate subsurface deposits of metals. However, surface changes were only consistently produced by zinc and more particularly tin salts. Both zinc and tin salts produced covering or obturation of tubules. The surface effects of zinc could largely be reversed by washing, but not those of tin. Formaldehyde alone or in the presence of saliva produced no effects. A 4‐week study involving twice daily exposure of specimens to saliva and fluoride, metals or formaldehyde yielded essentially the same results. It is unlikely that, except for tin, the compounds tested achieve their apparent clinical effects mediated by direct occlusion of dentinal tubules.
Simple methods for denture identification: a clinical trial
Authors: HEATH J. R. , ZOITOPOULOS L. , GRIFFITHS C.
Published: June 2007

The persistence of identification marks applied to dentures with two‐spirit solvent based fibre tip pens and graphite pencil covered with an experimental and a proprietary sealant were studied under service conditions. In general, the marks applied with the pens were rapidly lost, but those covered with the sealants persisted satisfactorily. The experimental sealant performed slightly better than the proprietary product.
Investigation of the aetiopathogenesis of amelogenesis imperfecta through microscopic, submicroscopic and cytogenetic methods—a case report
Authors: KORAY F. , SOYMAN M. , ERDOǦAN G.
Published: June 2007

A case of hypomineralized type of amelogenesis imperfecta has been evaluated by using microscopic, submicroscopic and cytogenetic techniques. It has been observed that some of the enamel contained hydroxyapatite crystals and showed normal mineralization, but some others consisted of transparent, crystal plates of octacalcium phosphate, revealing that these enamel prisms have hypomature characteristics. Extra chromosomes which belong to D‐autosomes were found in the culture obtained from the peripheral blood of the patient, suggesting that the patient has 15% hyperdiploids. It is suggested that the structural disorders in some of the enamel prisms resulted from alterations in the environmental conditions related to chromosome anomalies.
Effect of elimination of occlusal interferences on signs and symptoms of craniomandibular disorder in young adults
Authors: KIRVESKARI P. , LE BELL Y. , SALONEN M. , FORSSELL H. , GRANS L.
Published: June 2007

Sixty‐two dental students judged not to be in need of treatment for craniomandibular disorder (CMD) were randomly divided into two groups, one receiving occlusal adjustment and the other mock adjustment. A double‐blind study design was applied. After 2 years of education in dentistry, including courses in stomatognathic physiology, the increase in the subjective symptoms of CMD was significantly greater in the placebo control group than in the treatment group. The difference between the groups in the increase of sites tender to palpation was less clear, showing only a trend. However, the increase was statistically significant within the placebo group but not within the treatment group. Prophylactic occlusal adjustment thus appears to be effective in reducing the occurrence of symptoms of CMD, and possibly also the occurrence of clinical signs.
Dentine hypersensitivity. II. Effects produced by the uptake in vitro of toothpastes onto dentine
Authors: ADDY M. , MOSTAFA P.
Published: June 2007

Toothpastes arguably are the most common preparations used in the treatment of dentine hypersensitivity. Evidence for efficacy largely comes from clinical trials, and supports the role of the contained so‐called “active” ingredient. How such compounds produce therapeutic benefit has received limited attention. This study measured the availability and uptake onto dentine of fluoride and metal ions contained in commercial and test toothpastes. The effects of exposure of dentine sections to these toothpastes, and abrasive only pastes in particular, was investigated by scanning electron microscopy and X‐ray microanalysis. Aqueous extracts of the different toothpastes contained measurable concentrations of the incorporated metal and or fluoride, but usually considerably below that incorporated by the manufacturer. Extraction of dentine sections exposed to toothpaste slurries revealed levels of fluoride and metal ions, although post‐treatment washing in water reduced these levels. Surface changes at 1 and 10 h were not consistent with the uptake of fluoride or metals. These changes were almost certainly produced by the contained abrasives, including calcium carbonate, dicalcium phosphate, alumina and silica. In particular fume silica progressively accumulated on the dentine surface to narrow and occlude dentinal tubules. Unlike other abrasives fume silica was resistant to removal by washing. It would appear that insufficient attention has been given to the therapeutic potential of toothpaste ingredients, particularly abrasives, to produce benefit by occlusion of dentinal tubules.
Water sorption and solubility of resin‐based materials following inadequate polymerization by a visible‐light curing system
Authors: PEARSON G. J. , LONGMAN C. M.
Published: June 2007

The water sorption and solubility of three hybrid and one microfine composite are reported. The values obtained are dependent on composite type and resin system. Incomplete polymerization of the two materials resulted in increased solubility and sorption due to incomplete conversion of the monomer. The marked increase in both parameters will have clinical significance on the durability of the material.
Wearing of removable partial dentures in relation to periodontal pockets
Authors: TUOMINEN R. , RANTA K. , PAUNIO I.
Published: June 2007

Using a representative sample of 5028 dentulous Finnish adults the occurrence of periodontal pockets was studied separately for the maxillae and the mandibles among removable partial denture (RPD) wearers and non‐wearers. RPD(s) were worn in 11.2% of the 3444 maxillae with at least four natural teeth remaining, and in 7.7% of the 4706 corresponding mandibles (P<0.001). Periodontal pockets were more frequently observed in maxillae than mandibles. Wearing of RPDs highly significantly (P<0.0001) increased the odds of having periodontal pockets in general (4 mm or more) as well as the odds of having deeper periodontal pockets (exceeding 6 mm). This phenomenon was observed both in the maxillae and in the mandibles. These results suggest that wearing of RPD is a threat to periodontal tissues and that dentists should take care to frequently recall their patients fitted with RPD(s). During the recall visits more attention should be paid to the periodontal conditions of patients wearing RPD(s).
Physical properties of two new crown and bridge veneering resins
Authors: GREENER E. , DUKE S.
Published: June 2007

The degree of conversion and physical properties of two contemporary resin veneers based on light‐cured microfilled composite formulations and employing proprietary curing systems were evaluated. Visio‐gem (V) and Dentacolor (D) were polymerized using the appropriate curing systems. Polymer structure and degree of conversion were determined by Fourier transform infra‐red (FTIR) techniques. Physical properties, including depth of cure, compressive and diametral tensile strengths, hardness, thermal expansion and colour stability were determined by standard test modalities. Both materials appear to have the properties of typical microfilled resins including low compressive yield strengths and high thermal expansion coefficients. The curing system for V produced an increased depth of cure compared to conventional light curing techniques and the D system, but no clinically significant increase in the physical properties.
Comparative electromyographic study of elevator muscles in patients with complete dentures and natural dentition
Authors: MIRALLES R. , BERGER B. , IDE W. , MANNS A. , BULL R. , CARVAJAL A.
Published: June 2007

An analysis of integrated electromyographic (IEMG) activity of masseter and anterior temporal muscles was undertaken in fifteen patients with complete dentures and eight adult subjects with natural dentition.

Bipolar surface electrodes were used for IEMG recordings during maximal voluntary clenching and saliva swallowing in the inter‐cuspal position.

The IEMG activity of both muscles during maximal voluntary clenching was significantly lower in patients with complete dentures than in subjects with natural dentition. During saliva swallowing the activity in both muscles was similar in both groups. This may have a great clinical significance in the maintenance of the functional state of the different structures of the stomatognathic system in complete denture wearers, since the process of swallowing is a 24‐h function repeated about 600–2400 times each day.
The determination of the electrical potential of a metallic restoration in the oral cavity
Authors: MULLER A. W. J. , DE GROOT D. A. J. , DAVIDSON C. L.
Published: June 2007

An improved method for measuring the electrical potential of a metallic restoration is proposed and tested. Care was taken to avoid disturbing the restoration surface, hence it was not cleaned or dried. The probe tip was a gold‐plated pin, insulated from the saliva by soft wax. The probe was pressed through the wax on to the restoration just before measurement. An Ag/AgCl reference electrode was in contact with the saliva. The probe and the tip of the reference electrode were disposable.
A comparative study of the bond strengths of amalgam and alloy–glass ionomer cores
Authors: ARCORIA C. J. , DE WALD J. P. , MOODY C. R. , FERRACANE J. L.
Published: June 2007

The purpose of this study was to compare the bond strengths of dental amalgam cores and dental alloy‐glass ionomer cores that were luted to cast gold crowns with glass ionomer cement. Seventy‐two human extracted molars were sectioned horizontally and four regular thread mate system pins were inserted into a flat pulpal floor. The teeth were restored with amalgam or alloy‐glass ionomer admixture and prepared for crown preparations. Castings were produced with type III gold and cemented to the cores with Fuji type I glass ionomer cement. Thirty‐six of the specimens were subjected to thermal fatigue by cycling between 4 and 50°C for periods of 1, 5 and 10 weeks. The remainder of the specimens were retained in deionized water at 37°C. Bond strengths of the cores, in tension, were measured with a universal testing machine. The alloy‐glass ionomer cores exhibited higher bond strengths than the amalgam cores for virtually all time periods, particularly the thermocycled samples. The alloy‐glass ionomer cores exclusively displayed core fractures and pin/tooth insufficiencies while the amalgam cores failed because of a deterioration of the glass ionomer luting cement.
The recognition of craniomandibular disorders—an evaluation of the most reliable signs and symptoms when screening for CMD
Authors: BEZUUR J. N. , HANSSON T. L. , WILKINSON T. M.
Published: June 2007

Two hundred and twenty‐two patients who had been examined and treated for craniomandibular disorders were re‐evaluated using a screening protocol. This protocol was developed from previous studies which had elucidated the most reliable signs and symptoms of craniomandibular disorders. Unilateral signs and symptoms were found to be more common than bilateral signs and symptoms. Dynamic and static pain tests were shown to be decisive in determining the preliminary diagnosis. There was a significant difference in vertical condylar height asymmetry between those patients diagnosed as having a myogenous and an arthrogenous origin of pain.
Bridges in general dental practices: a descriptive study of the types of bridges and patients*
Authors: LEEMPOEL P. J. B. , VAN ROSSUM G. M. J. M. , DE HAAN A. F. J. , REINTJES A. G. M.
Published: June 2007

Based on data from patient records from a random sample of Dutch general practices, a study was made of the bridge distribution pattern in different patient groups. Patient variables such as age, sex and insurance type were analysed. More women had a bridge inserted than men. However, there appeared to be no difference in the average quantity of bridges in men or women. The abutment teeth most frequently used were the cuspids in the maxilla and the second premolars and second molars in the mandible. Fourteen per cent of the bridges consisted of five or more units, 14% were free‐end bridges, 13% did not meet Ante's law and 16% had one or more non‐vital abutment teeth.
Balance in masticatory muscle activity during natural chewing and submaximal clenching
Authors: McCARROLL R. S. , NAEIJE M. , HANSSON T. L.
Published: June 2007

The balance in the electromyographic (EMG) activities of the left and the right masseter and the left and right anterior temporal muscles during chewing and during submaximal clenching at 10% and 50% of the maximum voluntary contraction in the inter‐cuspal position was investigated in twenty healthy adults. Muscular asymmetry patterns during chewing and clenching were positively correlated for both pairs of masticatory muscles investigated at the 50% level (P<0.01‐P<0.001) and for the masseter muscles, also at the 10% level (P<0.01). Stronger correlations in muscular asymmetry were found for the masseter muscles and at the higher submaximal clenching level. In general, the masseter muscles displayed a greater degree of asymmetric activity than the anterior temporal muscles during both chewing and clenching (0.05<P<0.1−P<0.025). The average EMG amplitudes of both masseter or both anterior temporal muscles within each subject showed no correlation between clenching and chewing. The correlations between muscular asymmetries observed during static (clenching) and dynamic (chewing) conditions suggest that there are common factors influencing these activities.
Colour measurements of all ceramic crown systems
Authors: ROSENSTIEL S. F. , PORTER S. S. , JOHNSTON W. M.
Published: June 2007

The objectives of this study were: (i) to determine variability among colour parameters of five different ceramic crown systems; and (ii) to measure the effect of using coloured luting agents on restoration colour. The crown systems studied were Cerestore, Dicor, Hi‐Ceram, Renaissance, and Vitadur‐N. Five crowns for each system were made according to manufacturer's instructions with the same nominal shade (Vita LuminVacuum A2) to fit an Ivorine central incisor tooth. Restoration thickness was adjusted to within ±0.1mm (±0.05mm in the mid‐facial area where colour measurements were to be made) with the aid of a dial calliper prior to glazing or, in the case of Dicor, surface staining. Where a core was part of the system this was fabricated to the minimum recommended thickness. The crowns were cemented using luting agents of five different colours in a randomly chosen sequence. The colour of each restoration/cement combination was measured three times using a small‐area colorimeter (Minolta CR‐121). The variance of each colour parameter (L*,a*,b*) was statistically compared for each crown system using an analysis of variance procedure, as was the effect of the cement. Observed differences were related to visual perception by using the colour difference formula. There were statistically significant differences among the variances of the crown systems and the cements, with significant interactions between crown systems and direction of colour and between‐ cement and direction of colour. Restorations made with different ceramic crown systems had noticeably different colour despite having the same nominal shade. Changing the shade of the luting agent had a perceivable effect on Dicor crowns and, to a lesser extent, on Vitadur‐N crowns but not on the other systems due, presumably, to the opacity of their core materials.
Clinical performance of resin‐bonded bridges: a 5‐year prospective study. II. The influence of patient‐dependent variables
Authors: CREUGERS N. H. J. , SNOEK P. A. , VAN'T HOF M. A. , KÄYSER A. F.
Published: June 2007

A total of 203 resin‐bonded bridges was inserted under controlled clinical conditions and evaluated for a number of patient‐dependent variables over a period of 5 years. Of the variables evaluated only ‘initial occlusion of the abutment teeth’ and ‘location in the dental arch’ had a significant influence on the retention of resin‐bonded bridges. Anterior resin‐bonded bridges were more durable than posterior bridges. Mandibular posterior bridges showed the lowest retention ratio. It is concluded that the design of posterior resin‐bonded bridges should include tooth preparation or a wrap‐around design of the retainers.