bluuebunny/crossref_metadata_2025 huggingface dataset:
The experimenter effect on results with oral form recognition tests and with tests measuring oral muscular ability*
Authors: LANDT HORST , AHLIN LARS , LINDQUIST LARS
Published: June 2007

In the introductory part of the present study considerable differences in registrations were found between three different experimenters when an oral form recognition test and an oral muscular‐motor test was applied on ten subjects.

In the following part recording differences between six other experimenters were evaluated. An intensive training programme was established and repeated twice with those six experimenters during a test period during which twenty‐eight subjects were tested with the same tests as mentioned above. The results show that in spite of the training programme, uniformity could not be obtained between experimenters.

Registration deviations were (1) clearly found for the time results of identifying, (2) less distinctly for registration of subjective judgements of difficulty or for the times of putting together the halves of the test pieces in the test of muscular‐motor ability and (3) not at all at the recording of test piece confusions at the oral form recognition test.

It was found that the present forms of the training programme alone were not sufficient to gain uniformity between different experimenters but the suitability of prospective experimenters who are supposed to form a common group should be tested by an evaluation of test results found in a real test situation. Experimenters who are clearly deviating, should be replaced by other ones for the task who are more suitable individuals.

The present study thus emphasizes the previously observed difficulties when clinical observations made by different persons are to be compared.
Adaptation of silicate and Adaptic to the margins of cavities
Authors: SELA M. , SELA J. , ARAD T. , ULMANSKY M.
Published: June 2007

The effects of etching of the enamel, on the adaptation of silicate and Adaptic to the cavity walls was examined with the scanning electron microscope. Replica methods were utilized to ensure that no shrinkage of the filling materials was caused by the vacuum in the instrument. It was shown that following etching of the cavity margins, Adaptic adhered to the enamel with absent, or minimal, fissure formation on one side of the filling, and some on the opposite side. The adaptation of silicate to the margins of the cavities was not improved by etching.
Some effects of experimental hyperactivity of the mandibular locomotor system in man
Authors: CHRLSTENSEN L. VESTERGAARD
Published: June 2007

A review of recent literature on the effects of experimental hyperactivity of the mandibular locomotor system of man is presented, with special reference to the effects on the nervous, muscular and vascular components of this locomotor system.
Linear dimensional change during setting of a zinc phosphate cement
Authors: ØILO GUDBRAND
Published: June 2007

A method for studying the linear dimensional changes of dental cements during setting has been described. The measurements started 3 min after commencing the mix with specimens placed on a mercury bath. Measurements were performed at 37°C a.nd under various environmental humidity.

The specimens were made of a fine grain zinc phosphate cement with high powder/ liquid ratio (3/1: g/ml) and low powder/liquid ratio (2/1: g/ml), and the measurements showed that the cement contracted during setting under both wet and dry conditions.

Under wet conditions cements with both high and low powder/liquid ratio showed the same contraction, with 0.43% after 30 min reaching a maximum of 0‐66% after 1 day.

Under dry conditions the contraction was more pronounced, and somewhat dependent on the powder/liquid ratio. The cement with the high powder/liquid ratio showed 1.33% contraction after 30 min with a maximum of 3.83% after 7 days, whereas the corresponding values for cement with low powder/liquid ratio were 0.79% and 4.76%.
Cleanser solution effects on denture base resins
Authors: ROSSIWALL B. , NEWESELY H.
Published: June 2007

Scanning electron microscopic investigations were conducted to determine morphostructural alterations on denture base resin surfaces after immersions in commercially available oxygen liberating denture cleansers. The topography of properly processed denture resins did not show corrosive effects, whereas inconsistent surface characteristics of improperly processed wet‐mix acrylates could suggest less resistance. In spite of thorough rinsing after immersion, deposits were noted on the resins of varying amount, size, and quality according to the cleanser used. A possible clinical relevance of such deposits is yet to be evaluated.
The concept of oral rehabilitation*
Authors: FRANKS A. S. T.
Published: June 2007

Dentistry must re‐examine its professional obligations towards the patient and consider whether its present basis is too rigidly technical. Oral rehabilitation can be defined in terms of the restoration of function and aesthetics. However, it must include also a philosophy of concern for an oral invalid who may require continued and varied help in the management of his disability. The understanding of this concept requires an analysis of the meaning and impact of an oral disorder on an individual, and the responsibilities of those who have to provide him with guidance. Consideration must be given to the reflections of these principles of care on the teaching of dental students.
Frequency of symptoms of mandibular dysfunction in young Swedish men
Authors: MOLIN CARL , CARLSSON GUNNAR E. , FRILING BO , HEDEGÅRD BJÖRN
Published: June 2007

The occurrence of symptoms of dysfunction of the masticatory system was studied in 253 Swedish men from the region of Stockholm with an average age of 19 years. Besides inquiry by questionnaire regarding subjective symptoms a clinical functional examination of the masticatory apparatus was performed.

Fourteen per cent were aware of clicking of the temporomandibular joint and 12% of other symptoms of dysfunction such as difficulties in opening the mouth wide, locking and pain on performance of various movements of the mandible. In the clinical investigation, symptoms of dysfunction were noted in 28 % of those examined, mainly in the form of tenderness to palpation over the temporomandibular joints and of the masticatory musculature as well as difficult, painful and irregular movements of the mandible.

Individuals with clinical symptoms of dysfunction of the masticatory system had a higher frequency of other joint and muscle symptoms, clicking of the temporomandibular joint and occlusal disturbances in the form of balancing side interferences, than those without clinical symptoms. Balancing side interferences were the only occlusal disturbance that was significantly correlated with the symptoms of dysfunction (pain on movement and tenderness to palpation).
A long‐term prognosis for the fixed saddle‐bridge
Authors: IZIKOWITZ LENNART
Published: June 2007

This report constitutes a long‐term study of 100 saddle‐bridges applied by the author during the years 1958–1973. The aim of the investigation has been to assess the prognosis for this form of therapy. The probability that a saddle‐bridge will still be functioning completely, without repair, after 5 years is 93 %, and after 10 years (as also after 12 years) 83%. Only 12% of the appliances had been removed 12 years after the application.

The risk of defects is about the same during the first 5‐year period after the application as it is during the second and the third 5‐year periods. A comparison between saddle‐bridges applied before and after 1965 shows no demonstrable difference as regards the 5‐year prognosis in spite of modifications with respect to range of indication and therapy.

The causes of the defects have been divided into biological and technical. During the first 5‐year period technical defects appear to be in the majority, whereas during the later stages, biological defects predominate. Background factors such as sex, the age of the patient, length of saddle, localization in the jaw do not prove to have any appreciable importance for the prognosis. There is, on the other hand, a significantly better prognosis when the opposing jaw is furnished with the patient's own teeth and/or fixed bridges than with a removable denture.

The author points out that from the result of the study, the saddle‐bridge has such a good long‐term prognosis that its range of application for fixed constructions should be considerably extended.
Abrasion of restorative materials by toothpaste
Authors: HEATH J. R. , WILSON H. J.
Published: June 2007

A method of measuring toothbrush‐dentifrice abrasion of restorative materials is described. The method also includes a quantitative assessment of surface roughness. Values of wear and surface roughness of a range of restorative materials are presented.
Disturbances in the contraction and co‐ordination pattern of the masticatory muscles due to dental restorations
Authors: KLOPROGGE M. J. G. M. , van GRIETHUYSEN A. M.
Published: June 2007

Recent Swedish publications report that a large number of patients suffer from the mandibular dysfunction syndrome. Some theories assume that this syndrome is the result of a disturbance in blood flow through the maxillary artery.

The present authors suggest, that the syndrome is caused by a disturbance in the pattern of contraction of the masticatory muscles. This hypothesis is based on the assumption that the human periodontal membrane contains mechanoreceptors which are able to exert reflex control over the pattern of contraction of the muscles during chewing.

If the pattern of stimulation of these receptors is modified following dental restoration, then this could result in a disturbance of the neuromuscular pattern of the masticatory apparatus. In order to test this hypothesis, an electromyographic study was carried out in three volunteers and eight patients. The results of this study support the view that there are receptors in the human periodontal membrane which are able to control the pattern of contraction of the masticatory muscles.

The hypothesis that the mandibular dysfunction syndrome is the result of a disturbance in the pattern of contraction of these muscles is pursued further in the discussion.
The long term bonding of a polymeric fissure sealant to stannous fluoride treated enamel
Authors: LOW T. , VON FRAUNHOFER J. A. , WINTER G. B.
Published: June 2007

A report is presented of extended studies of tensile bond strength of Nuva Seal to fluoride‐treated enamel 1 week, 3 months and 9 months after application. The differences in strength were not statistically significant. The use of stannous fluoride as the topical agent did not lead to any marked evidence of enamel staining.
The role of retro‐disclusion in the treatment of the TMJ‐patient
Authors: GAUSCH KURT , KULMER SIEGFRIED
Published: June 2007

A clinical procedure is described for treatment of patinets with condylar malposition. The method of construction of the occlusal splint used is outlined and its mode of action discussed.
Evoked EMG of masseter and temporal muscles in man
Authors: FUJI HIROYUKI
Published: June 2007

Following a percutaneous stimulation on the mandibular notch skin, two kinds of responses were recorded in the ipsilateral masseter and temporal muscles in man. The two responses had their proper stimulating points. The early response appeared with about a 2 ms latency and the late one with about 6 ms latency which was shorter than that of T wave of the same muscle by about 1 ms. No responses were induced in the contralateral masseter and temporal muscles.

Regarding the recovery process of the late response following double stimuli, a testing late response was released about 100% from the effect of conditioning shock at a longer interval than 80∼95 ms. It might be safe to consider that the previous assumption, i.e. those two responses seemed to be M and H waves respectively, had been fortified. H response evoked in muscles tested seems to be sensitive enough to show the difference between excitatory states of its reflex arc.
Removal time: a factor in the accuracy of irreversible hydrocolloid impressions
Authors: KHAKNEGAR BIJAN , ETTINGER RONALD L.
Published: June 2007

Controversy exists regarding the correct time of removal of an alginate impression from the mouth. to investigate the effect of time of removal on accuracy, a series of alginate impressions were made of the lower left quadrant of a subject having a cast gold crown with four reference marks on tooth No. 19. The impressions were removed from the mouth at 1.5,2,3,4.5 and 7 min after the insertion of the tray. Accuracy of the impressions was assessed by comparing the distances between the reference marks in stone casts with standard measurements taken from the gold crown prior to cementation.

Impressions removed at 1.5 and 7 min produced the greatest distoritions buccolingually. For the mesio‐distal lengths all time intervals produced casts which were larger than the standard. The reasons for these findings are discussed and possible explanations are presented.
A 3‐months'study of enzymes as denture cleansers
Authors: BUDTZ‐JÖRGENSEN E.
Published: June 2007

It was the purpose of the study to test the efficacy of dissolvent tablets containing mutanase and protease in removing denture plaque. The study group consisted of forty institutionalized geriatric denture wearers, who were assigned randomly into an enzyme group and a placebo group. Enzyme tablets and placebo for denture soaking were administered by the nurses. The dentures were immersed for 15 min once daily for three months. The amount of denture plaque, the clinical condition of the palatal mucosa, and the concentration of yeasts and bacteria in mucosal and denture smears were recorded before, during, and after the experimental period. The study was designed and carried out as a double‐blind study. After denture soaking for six weeks a significant reduction of the amount of denture plaque and improvement of the clinical condition of the palatal mucosa was recorded. After denture soaking for twelve weeks the conditions had improved further when comparing the enzyme group with the placebo group.
Long term preventive aspects in oral rehabilitation of adults and elderly
Authors: LANGER A.
Published: June 2007

Prevention should be regarded as more important for the health than the cure. In adult and geriatric patients prevention is directed towards limiting disability rather than preventing the onset of the disease, since treatment is undertaken after pathological changes have taken place and some degree of invalidity is already present. Oral rehabilitation, if successfully performed, will limit the spread and further deterioration of oral conditions at any developmental stage of a functional pathology. The objective of the rehabilitation should not be the integrity of a single dental arch and certainly not the replacement of the lost teeth. Rather, the principle guiding the treatment should be the achievement of a harmonious functional relation between the maxillary and mandibular jaws, so as to enable them to function in well balanced co‐operation and force distribution. This objective may be best achieved by sensible planning and faultless execution, when the patient is younger, and most of his teeth and their supporting structures are still preserved.
A survey of partial denture design in general dental practice
Authors: BASKER R. M. , DAVENPORT J. C.
Published: June 2007

The objects of this investigation were to discover the methods by which general dental practitioners communicated partial denture designs to dental laboratories and to ascertain the extent to which certain design criteria were being followed. The results of the survey showed that the responsibility for design appeared to be largely delegated to the technician. In most instances cobalt‐chromium dentures were produced which would assist in maintaining oral health; however, this was not the case with acrylic dentures.
Activity of oro‐facial musculature during use of mouthpieces for diving
Authors: INGERVALL BENGT , WARFVINGE JOHAN
Published: June 2007

The EMG activity in the temporal muscle, masseter muscle, and in the lower lip was recorded during 27 minutes use of three makes of mouth‐pieces for air supply during diving. For comparison, recordings were made also of the muscle activity with the mandible in the postural position and during maximal bite. Five male amateur divers, aged 22–35, took part in the investigation.

The muscle activity necessary to hold the mouthpiece in position varied from one make of mouthpiece to the other. Compared with the activity with the mandible in the postural position, the activity in the lip increased most, and then considerably, during use of a mouthpiece. Two of the mouthpieces also raised the activity in the masseter muscle. The temporal muscle was affected least and showed an increase in activity during use of only one of the mouthpieces.

In the laboratory experiments the muscle activity necessary for retention of the mouthpieces was only a fraction of that during maximal bite. It is stressed, however, that the force with which the mouthpiece is gripped when diving may, owing to emotional factors, be much greater. To avoid undue muscle fatigue and pain it is therefore recommended to use the mouthpiece which, according to the laboratory studies, was shown to require the least muscle activity for retention.
Trauma from occlusion in monkeys
Authors: JOHANSEN JAN R. , KARLSEN KJELL
Published: June 2007

Traumatic occlusion was induced in monkeys by insertion of bridges raising the bite. Both incisors and molars were used as abutments. Observation periods ranged from 7 to 24 months. No appreciable effect of the trauma on the apical proliferation of the crevicular epithelium was found. The results were the same in monkeys with or without marginal gingival inflammation before the trauma was induced.
The influence of surface roughness on the retentive ability of two dental luting cements
Authors: ØILO GUDBRAND , JØRGENSEN KNUD DREYER
Published: June 2007

Two series of brass cones and two series of dentine posts with varying surface roughness were produced. Maximum roughness value and arithmetical mean roughness were recorded for each cone. Brass crowns were cemented either with zinc phosphate cement (De Trey's Zinc Cement Improved®) or with polycarboxylate cement (Durelon®). A tensile stress was applied until the crown and the cone separated. The retentive force in relation to retention area was measured.

The results showed that the retentive ability of both cements increased with increasing surface roughness. The increase in retention was greater for brass than for dentine. Differences were also found between the two cements; on smooth surfaces the zinc phosphate cement had a lower retentive ability than the polycarboxylate cement, but on rough surfaces the opposite relationship was observed.
Mesurement of lip posture and interaction between lip posture and resting face height
Authors: YEMM R , EL‐SHARKAWY M. , STEPHENS C.D.
Published: June 2007

A method for measurement of lip incompetence is described. Electromyographic techniques were used to obtain relaxation of the muscles of the lip and of a jaw elevator muscle. Standardized photographs were taken of the subject's profile, from which lip separation and face height were measured. Variation was found in successive measurements of lip posture, some of which appeared to depend upon mandibular posture. With the teeth in occlusion, lip separation was reduced. Active maintenance of lip contact by the subject was often associated with a reduction in lower face height, which may have been a direct consequence of the lip muscle activity, or of jaw elevator activity facilitating the lip closure.
Bite force and oral function in complete denture wearers
Authors: HARALDSON TORGNY , KARLSSON ULF , CARLSSON GUNNAR E.
Published: June 2007

Oral function was evaluated in complete denture wearers by using a questionnaire, clinical examination and bite force measurements. Ten patients with satisfactory and ten with unsatisfactory dentures were studied and six of the latter patients were reexamined 1 year after the insertion of new dentures. The bite force values were compared with those obtained in ten dentate controls.

No significant differences in bite force were found between the satisfactory and unsatisfactory denture groups. Individual values varied much in both groups. The six patients re‐examined were satisfied with their new dentures and thought they had improved chewing but no significant increase of bite force was found. The maximal bite force was 5–6 times greater in the dentate subjects than in the denture wearers. Edentulous persons are very handicapped in masticatory function and even clinically satisfactory complete dentures are poor substitutes for natural teeth.
The relationship between bruxism and temporomandibular joint dysfunction as shown by computer analysis of nocturnal tooth contact patterns
Authors: TRENOUTH M. J.
Published: June 2007

Whilst there are many causes of temporomandibular joint dysfunction, one of the most frequently encountered is bruxism. The two conditions have many aetiological factors in common and there is a rational physiological reason why bruxism could cause temporomandibular joint dysfunction. In fact, experimental bruxism performed under laboratory conditions has been found to cause such joint dysfunction.

This contention is supported by direct measurements of nocturnal tooth contact. Patients with temporomandibular joint dysfunction were found to differ from control subjects to a degree which was statistically significant.
Cervical enamel: a danger zone
Authors: DAVIS W. B.
Published: June 2007

The British Standards Institution's document (1974) recommending toothpaste specifications states that ‘There is no evidence that any toothpaste ever produces a level of abrasion causing harm to dental enamel’. This paper questions the assumption that the enamel crown, especially at the cervical margin, is able to cope with modern dietary insult and a ‘good’ oral hygiene regimen, regardless of the enamel abrasivity of the dentifrice used. Once the enamel crown is breached the underlying dentine is sensitive and vulnerable to physical damage. In this work the potential rates of erosive and abrasive loss are related to the thickness of the protective enamel and to the relevance of fluoride treatments for adults. It is suggested that improvements in dental care and an increased tooth life expectancy now make the loss of tooth tissues at the cervical margin more important than is apparent at first sight.
The reproducibility of movement parameters of the empty open—close—clench cycle in man and their dependency on the frequency of movements
Authors: NAEIJE M. , HONéE G.L.J.M.
Published: June 2007

The reproducibility of the empty open‐close‐clench cycle has been investigated. Four subjects were asked three times to perform thirty empty open‐close‐clench movements at each frequency of ½, 1 and 2 cycles s−1.

To describe such a series of thirty movements a set of nine parameters were selected. By reference to these parameters it was found that the subjects were not always able to exactly reproduce a series of thirty movements at a repeat test.

The movement‐parameters strongly depended on the frequency of the movements. On increasing the frequency the durations of time in which a movement cycle was divided decreased, while the maximum jaw speeds during opening and closing and the jaw speed just before tooth contact increased. The parameter values chosen to describe the smoothness of the movements performed, indicated that the smoother movements were executed at the higher frequencies.
Some subjective‐experiential parameters in experimental tooth clenching in man
Authors: CHRISTENSEN L. V.
Published: June 2007

Experimental tooth clenching was performed by fourteen human subjects in order to determine the onset of the subjective sensations of jaw muscle fatigue and jaw muscle pains, the ability to endure jaw muscle pains, and other discomforts. During production of maximal voluntary isometric tension by the elevator jaw muscles the fatigue threshold (x̄= 31 s), the pain threshold (x̄= 55 s), and the pain tolerance (x̄= 118 s) of tooth clenching did not vary significantly intraindividually, whereas this was so interindividually. There might have existed psychological relationships between the three parameters, but they might also have been influenced by the same physiological cause. The weak to intense discomforts were localized to the face, and primarily to the jaw muscles, and after determination of the pain tolerance they disappeared in about 90 s.
Distribution and evaluation of complete dentures in a population in Northern Norway
Authors: NORHEIM PER W. , VALDERHAUG J. JAKOB
Published: June 2007

The frequency and distribution of complete dentures were studied in a population of 358 persons aged 20–69 living in a community in Northern Norway.

Among the 83 % who attended the investigation, 49 % had a maxillary and 26 % a mandibular denture. The occurrence of dentures increased with increasing age and with decreasing income and/or social class, while dentures were almost equally common in both sexes, when differences of age and income were taken into account.

Of the participants between 50–69 years 39 % had received their first maxillary denture at the age 17–24 years. In the age group 30–49 years the corresponding percentage was 20.

Forty‐four percent of the participants had maxillary dentures and 33 % mandibular dentures which were older than 10 years. According to an index on the clinical evaluation of complete dentures as well as to the denture wearers' own opinion, the insufficiency of the dentures tended to increase with increasing age of the dentures. Sex, age, income and social class, however, were found to have only a minor effect on the age and the condition of the dentures as well as on the denture wearers' degree of satisfaction with their dentures. Persons who had natural mandibular teeth, tended to be less satisfied with their maxillary dentures than persons with complete dentures in both jaws.
The structure of experimental in vitro lesions around glass ionomer cement restorations in human teeth
Authors: WESENBERG GRO , HALS EINAR
Published: June 2007

Class V cavities were prepared at the amelo‐cementum junction in sixty‐eight extracted human teeth. Fifty‐one were filled with glass ionomer cement (ASPA R′). ‘Secondary carious’ lesions were produced around thirty‐five of the restorations by exposure to acidified gelatin. Thirty‐three teeth served as controls of the effect of the preparation procedure, the conditioner, the ASPA liquid and the filling material proper on the cavity walls.

Sixty 120 μm‐thick longitudinal sections from the teeth with the restorations in situ were studied by polarized light microscopy and microradiography.

The glass ionomer cement caused by itself a narrow zone of increased radiopacity in the dentine cavity wall. The ‘secondary caries’ pattern consisted of a subsurface outer lesion and a subsurface wall lesion as observed previously in corresponding experi ments with silicate fillings. Outer‐ lesions in enamel were more frequent than with silicate cement.

In the cementum all the experimental teeth showed outer lesions. The wall lesions extended only slightly beyond the level of erosion of the restorations. Between the wall lesions (in dentine) or outer lesions (in cementum dentine) and the surface of the cavity wall, a zone of increased radiopacity was found, assumed to be due to reprecipitation of Ca and P promoted by release of fluoride from the filling material.
An in vitro study of marginal leakage associated with composite restorations using an acidified agar technique
Authors: GRIEVE A. R. , GLYNJONES J. C.
Published: June 2007

The marginal leakage associated with a composite restorative material was examined using an in vitro method for the production of secondary caries‐like lesions after the restorations had been subjected to thermal cycling. The fillings were placed in cavities with a 90° cavo‐surface angle with and without etching of the walls with phosphoric acid and in cavities with a bevelled margin which were also acid etched. Some degree of leakage was demonstrated in 95% of the unetched cavities while approximately half of the restorations in etched unbevelled cavities showed leakage. With the bevelled and etched group virtually no leakage occurred.
The surface structure of the temporomandibular joint disk: a scanning electron microscopic study
Authors: JAGGER R. G.
Published: June 2007

The surface appearance of seven temporomandibular joint disks obtained at postmortem has been studied by scanning electron microscopy. Two of the disks had lateral perforations which corresponded, in position, to macroscopic changes in the condylar and temporal joint components.

The nature of the disk surfaces has been described. The central portion of the disks consisted of tightly bound collagen bundles; the bundles of the anterior and posterior parts were more loosely bound and irregularly orientated.

The implications of the findings have been discussed in terms of articular function and dysfunction and of disease processes within the joint.
The use of differential scanning calorimetry for the evaluation of dental materials
Authors: McCABE J. F. , WILSON H. J.
Published: June 2007

The presence of thermal transitions within the working range of denture base polymers may have a drastic effect on the dimensional stability of the material. The glass transition temperatures of fifteen denture base polymers have been measured and their significance discussed. The effect of thermal contraction and polymerization contraction on dimensional stability is not fully understood at the present time. An attempt has been made to explain the dimensional changes which occur in denture bases with the aid of transition temperatures and inferred thermal contraction and polymerization contraction values.
Microporosity in bis‐glycidyl methacrylate films
Authors: WILLIAMS B. , von FRAUNHOFER J. A.
Published: June 2007

The existence of hitherto unsuspected micropores in fissure sealant films (bis‐glycidyl methacrylate resin films) has been demonstrated by means of scanning electron microscopy. Immersion of specimens in various ionic solutions showed that the defects in the surface of the resin film tended to become filled with the passage of time.
Book reviews
Authors: FRANKS A. S. T. , WILSON H. J. , FOSTER T. D. , WADE O. L. , STENGELHOFEN J.
Published: June 2007

Books reviewed in this article.

Temporo‐Mandibular Joint: Function and Dysfunction ED. By G. A. Zarb and G. E. Carlsson.

An Outline of Dental Materials and their Selection Ed. by William J. O'Brien and Gunnar Ryge

A Colour Atlas of Clinical Conditions in Paedodontics Ed. by Robert Rapp and Gerald B. Winter.

Lecture Notes on Drugs for Dental Students Ed. by T. J. Wilkin and P. N. Davidson.

A Career in Speech Pathology Ed. by Charles Van Riper.
The management of patients with severe hypodontia
Authors: HOBKIRK J. A. , BROOK A. H.
Published: June 2007

Severe hypodontia is thought to be caused by hereditary and environmental factors. It has a population incidence of 0.3% in the permanent dentition, being much rarer in the deciduous dentition. The management of patients suffering from this condition is described, including the use of conservative, prosthodontic and orthodontic procedures.
Some electromyographic parameters of experimental tooth clenching in children
Authors: CHRISTENSEN L.V.
Published: June 2007

Twelve children exercised maximal voluntary tooth clenching until pains appeared (pain threshold) in the right masseter muscle and could no longer be endured (pain tolerance). Concomitantly the integrated electrical activity of the muscle was determined as a ratio of the isometric is muscle exercises. It is possible that the two exercises were accompanied by progressive muscle fatigue. While changes in the pain threshold could not be related to similar changes in the accompanying electrical muscle activity, the pain tolerance seemed to increase with a decrease in electrical muscle activity. To a large, but unknown, extent the pain threshold might have depended on psychological factors, rather than electrical muscle activity, whereas the pain tolerance to a large, but unknown, extent might have depended on the electrical muscle activity. The muscle activity of the two subjective tests might have been influenced by the same physiological determinants, e.g. progressive muscle fatigue and ischaemia of the muscle tissue. The number of teeth in contact during the isometric muscle exercises and the size of the gonial angle of the mandible did not influence either the pain threshold and pain tolerance or the muscle activity of these tests.
Pulpal response to a temporary crown and bridge material in ferret teeth
Authors: TOBIAS ROSALIND S.
Published: June 2007

The histological effects of a temporary crown and bridge material (Scutan) on the pulp of canine teeth of ferrets was investigated at time intervals up to 6 months. After 24 h a moderate to severe pulpal response was observed which persisted up to 6 months. A case of contact sensitivity to Scutan is reported.
Behaviour of teeth under various loading conditions with finite element method
Authors: TAKAHASHI NORIAKI , KITAGAMI TETSUYA , KOMORI TOMIO
Published: June 2007

A study was made of behaviour of the upper central incisor, lower second premolar and lower first molar under various loading conditions, with the finite element method. Analysis was made of tooth deflections, rotational centre, stresses in the periodontal membrane, turning moments of tooth and supporting forces of the periodontal membrane.

It was shown that the horizontal vector of load was much more influential to the teeth than the vertical vector, and that effects of the loading angle on the tooth behaviour were found most markedly in the lower first molar, followed by the lower second premolar and upper central incisor in decreasing order.
An in vitro model for studying adsorption of oral streptococci to crown and bridge cements
Authors: ØRSTAVIK JON , ØRSTAVIK DAG
Published: June 2007

A sensitive, in vitro method has been developed for the study of bacterial adsorption to dental crown and bridge cements. The method employs heavily radiolabelled cells which adhere to the wall in wells made from the cements. Loss of radioactivity from the bacterial suspension during incubation is used to measure the degree of bacterial adherence to the materials.

Strains of Streptococcus sanguis and Streptococcus mutans adhered in greater numbers than a strain of Streptococcus salivarius to both a zinc phosphate cement and a zinc carboxylate cement. The zinc phosphate cement supported adherence to a greater degree than did the zinc carboxylate cement. Pretreatment of the cement surfaces with human saliva tended to reduce bacterial adherence. Pretreatment of the bacteria with saliva slightly enhanced sorption of S. sanguis and S. salivarius, but tended to impair sorption of S. mutans to both types of cements. When both bacteria and cements had been pretreated with saliva, a strong inhibition of the adherence of S. mutans was observed.
Toothpaste abrasive requirements to control naturally stained pellicle
Authors: BAXTER P. M. , DAVIS W. B. , JACKSON J.
Published: June 2007

Toothpaste abrasivity should be sufficiently high to give effective cleaning without causing mechanical damage to tooth tissue. A clinical trial carried out to measure the cleaning power of calcium carbonate toothpastes of different abrasivity is described; cleaning power is then related to in vitro dentine abrasivity measurements. These findings are used to derive an expression specifying the toothpaste cleaning power which ensures that a chosen low and cosmetically acceptable level of stain is not exceeded providing a consistent daily brushing routine is adhered to.
Jaw muscle fatigue and pains induced by experimental tooth clenching: a review
Authors: CHRISTENSEN L.V.
Published: June 2007

Maximal voluntary isometric contractions of the elevator jaw muscles, with the mandible in the position of maximal intercuspation of the natural teeth, can induce fatigue and weak as well as severe pains in the jaw muscles of children and adults. A subjective sensation of muscle fatigue appears after about 0.5 min of clenching, and it seems as if the psychological parameter of fatigue onset to a large, but unknown, extent is determined by the physiological parameter of the amount of isometric contractile activity, and perhaps also the original strength of the muscle; however, also individual psychological factors seem to play a role. Pains in the elevator jaw muscles appear after about 1 min of clenching. Although isometric contractions are necessary to cause onset of jaw muscle pains, it is conceivable that the perception of the moment of onset of pains to a large, but unknown, extent depends on psychological factors, perhaps the intensity of pains; however, also physiological factors may play a role. The severe muscle pains and gradually increasing subjective exhaustion of the elevator jaw muscles can be endured for about 2 min of maximal voluntary tooth clenching. It is suggested that the psychological parameter of muscle endurance to a large, but unknown, extent depends on the physiological parameter of isometric contractile activity, but also individual psychological factors seem to play a role.
Patterns of cortical bone growth around alumina implants
Authors: HOBKIRK J. A.
Published: June 2007

Intra‐bony defects are frequently observed around endosseous implants. It has been thought that these are due to occlusal loading and infection. More recently it has been suggested that they may be related to implant shape. This hypothesis has been tested using alumina implants with flat, cone shaped and flared ends, which were inserted into the mandibles and iliac crests of rabbits. The implants remained in situ for up to 18 months and the tissue reaction was studied qualitatively and quantitatively using resin embedded histological sections. New bone was laid down parallel with the implant surface and at a pronounced angle to that in the cortex. Deep intra‐bony defects were seen adjacent to the flared implants and, to a lesser extent, the straight ones. Tapering implants appeared to encourage bone growth on the implant above the level of the cortex.
Mandibular flexure associated with muscle force applied in the retruded axis position
Authors: OMAR R. , WISE M. D.
Published: June 2007

The object of this study was to measure any mandibular flexure occurring in the horizontal plane, when R.A.P. recordings were made with an ‘anterior jig’ (Lucia, 1964), chin‐point guidance and patient‐applied muscle force.

The rationale for the experimental method was that any arch‐width change noted at the tooth level reflected a flexure of the mandible.

Ten subjects participated and the mean lateral flexure of the mandible in the horizontal plane was 0.073 ± 0.028 mm. As a corollary to the study, mean medial flexure of the mandible in wide opening movements was found to be 0.093 ± 0.044 mm, which was consistent with earlier workers’results.

On the basis of the results obtained, restorations constructed to muscle‐R.A.P. recordings could conceivably present as occlusal interferences and, indeed, articulators may require modification so as to allow for mandibular resilience.
Is a low viscosity bonding resin necessary?
Authors: RETIEF D. H. , WOODS E.
Published: June 2007

Low viscosity bonding resins have been introduced for use on etched enamel surfaces prior to the application of the viscous composite resins. In this in vitro study the effects of a low viscosity bonding resin on the bond strength, adaptation and microleakage of a composite resin to etched enamel were evaluated. The low viscosity bonding resin did not improve the tensile bond strength of a composite resin to etched enamel, did not increase resin penetration into etched enamel and did not decrease marginal leakage at the composite resin/etched enamel interface. The continued use of low viscosity bonding resins in clinical dentistry is questioned.
The influence of temperature on some physical properties of dental composites
Authors: BAUSCH J. R. , DELANGE C. , DAVIDSON C. L.
Published: June 2007

In this study diametral tensile strength and microhardness of composites were investigated in relation to various temperatures during curing. It has been demonstrated that temperatures elevated up to 60°C can improve the mechanical properties considerably. Also the stability of the resin system in aggressive environments was improved due to more efficient cross‐linking. Thermal analysis of the material showed an endothermic reaction between 60 and 70°C that is believed to be responsible for the initiation of the extra cross‐linking. Heating of composite fillings during clinical use is suggested.
Solubility of enamel powder following treatments with 1% sodium dodecyl sulphate in the presence and absence of fluoride
Authors: GALON E. , FRIEDMAN M. , GEDALIA I. , RAJSTEIN J.
Published: June 2007

Deionized water exerts a solubility effect on enamel which is increased in the presence of sodium dodecyl sulphate (SDS), at a concentration used in dentifrices.

As expected, incorporation of fluoride by enamel decreases the solubility effect of the detergent in water and acidic buffer. With duration of treatment, the detergent has a lesser effect than demineralized water alone on subsequent solubility of enamel in acidic buffer.
The silent period in the masseter and the anterior temporal muscles at repeated registrations
Authors: FURUYA RYOICHI , HEDEGÅRD BJÖRN
Published: June 2007

Three dental nurses took part in an investigation of the reproducibility of the EMG silent period. The latency and duration of the silent period after tooth tapping and jaw jerk were found to be rather stable within the same day and between recordings every other day for 10 days. No differences in the SP variables between right and left side were found. Differences in the latency and duration of the silent period between the masseter and anterior temporal muscles during tooth tapping and jaw jerk were registered. The findings suggest functional difference between the two muscles.
Distribution of stress patterns in the human zygomatic arch and bone
Authors: ALEXANDRIDIS C. , THANOS C. E. , CAPUTO A. A.
Published: June 2007

A three‐dimensional photoelastic model was reproduced from a human skull. The insertions of the superficial and deep portions of the masseter muscle and the temporalis fascia were simulated with leather bonded to the appropriate areas. The following loading conditions were employed: (1) bilateral loading of the masseter muscle; and (2) bilateral loading of the masseter muscle together with a bilateral occlusal load. The stress freezing technique was used to lock the resulting stress patterns into the model skull. The stress trajectories were observed and photographed in a circular polariscope.

The results suggest that the major stress trajectories to the zygomatic bone and arch follow an alveolo‐maxillary‐zygomatic‐temporal direction. Stresses were highly concentrated in the zygomatic process of the temporal bone. Generally, the stresses were concentrated in those areas of the bone where architectural reinforcement had been demonstrated by other methods.
Thermal conductive analysis of restored teeth by finite element method
Authors: TAKAHASHI NORIAKI
Published: June 2007

In order to clarify the thermal conductive effects of restorative conditions, interpulpal thermal changes of restored vital teeth with inlays and full crowns were analysed theoretically by a finite element method, under thermal irritation from cold and hot drinks. It was concluded that the thermal conductivity of the restorative materials and the thickness of remaining tooth structure both influenced the interpulpal temperatures of restored vital teeth.
Changes in recurrent headache and mandibular dysfunction after treatment with new complete dentures
Authors: MAGNUSSON TOMAS
Published: June 2007

The changes in headache and mandibular dysfunction were studied in a group of forty‐three complete denture wearers 6 months after treatment with new complete dentures. All patients completed a questionnaire and all were subjected to clinical examination of the function of the masticatory system. Eleven of the seventeen patients with recurrent headache reported less frequent headache 6 months after treatment and nine reported that the headache was less severe. There was also a statistically significant reduction of clinical signs of dysfunction of the masticatory system.
Fatigue testing of denture base polymers
Authors: STAFFORD G. D. , LEWIS T. T. , HUGGETT R.
Published: June 2007

Fatigue characteristics should be an important part of assessment of the behaviour of denture base polymers. Only limited studies have been completed to any extent, largely because of the difficulty in designing suitable machinery. A review of the clinical parameters required in such a machine is discussed, and the development of a multi‐station machine is described, with some preliminary results.
An evaluation of mechanical and adhesive properties of polycarboxylate and glass ionomer cements
Authors: NEGM M. M. , BEECH D. R. , GRANT A. A.
Published: June 2007

Mechanical and adhesive properties of polycarboxylate and glass ionomer cements were studied. Water had an adverse effect on the compressive and tensile strengths of both materials. Both cements showed good bonding to enamel and dentine. Bonds between polycarboxylate cement and sterling silver were strong enough to cause cohesive failure of the cement rather than adhesive failure, when the specimens were tested. Surface cleaning and conditioning with 5% sodium hypochlorite solution showed an improvement in the bonds of the cements to dentine and they were significantly stronger than the bonds formed after the use of 50% citric acid solution (ASPA conditioner.)
The size of the Balkwill angle and the height of the Bonwill triangle
Authors: OHM E. , SILNESS J.
Published: June 2007

The Balkwill angle and the height of the Bonwill triangle were measured on cephalograms of 128 adult females and males who had all their natural teeth. The size of the Balkwill angle was dependent on the choice of the condylar reference point, whereas the height of the Bonwill triangle was not. When analysed by sex, it was found that the Balkwill angle was larger in males than in females. Likewise, the height of the Bonwill triangle was larger in males.
A clinical re‐examination of patients treated with pinledge‐crowns
Authors: LUNDQVIST P. , NILSON H.
Published: June 2007

A group consisting of forty patients received a clinical and radiological re‐examination, of a cross‐sectional type, to examine the effects of pinledge‐crowns on teeth and periodontal tissues.

The mean age of the material, which consisted of patients treated at the Department of Prosthetics, University of Umea, during the period February 1969‐November 1971, was 48.6 years (18 ± 22°). In these patients fifty‐one pinledge‐crowns had been inserted, in 88 % of the cases on a canine tooth. In every person, the contralateral tooth served as a control tooth. The teeth were examined with regard to the frequency of failure (expressed as failure rate %/year), the presence of caries, and the periodontal status.

The results showed that of the total number of pinledge‐crowns (fifty‐one), twelve had been removed before the time of examination. At the examination it was found that one crown had extensive caries, which required a revision of the crown, and one tooth had a non‐sensitive pulp with a periapical osteitis. These fourteen (27.5%) pinledge‐crowns were classified as failures. The value of the failure rate expressed as %/year was, after 8 years, 3.43 pinledge/year or 3.13, if the patient was used as a unit.

Concerning the periodontal effects, the difference between teeth fitted with pinledge‐crowns and control teeth was small.