bluuebunny/crossref_metadata_2025 huggingface dataset:
Pathogenesis and modifying factors of dental erosion
Authors: Meurman J. H. , ten Gate J. M.
Published: October 2007

Dental erosion is caused by acidic solutions which come into contact with the teeth. Because the critical pH of dental enamel is approximately 5.5, any solution with a lower pH value may cause erosion, particularly if the attack is of long duration, and repeated over time. Saliva and salivary pellicle counteract the acid attacks but if the challenge is severe, a total destruction of tooth tissue follows. Ultrastructural studies have shown that erosive lesions are seen in prismatic enamel as characteristic demineralization patterns where either the prism cores or interprismatic areas dissolve, leading to a honeycomb structure. In aprismatic enamel the pattern of dissolution is more irregular and areas with various degrees of mineral loss are seen side by side. In dentin the first area to be affected is the peritubular dentin. With progressing lesions, the dentinal tubules become enlarged but finally disruption is seen also in the intertubular areas. If the erosion process is rapid, increased sensitivity of the teeth is the presenting symptom. However, in cases with slower progression, the patient may remain without symptoms even though the whole dentition may become severely damaged. Regarding the role of causative agents, present data does not allow the ranking of different acids with regard to their potential of causing erosion. Neither is there consensus as to how effective fluorides are in preventing the progression of erosive lesions, or how the chemical and structural factors of tooth tissue in general might modify this pathological process.
Effects on salivary flow rate and composition of withdrawal of and re‐exposure to the β1 ‐selective antagonist metoprolol in a hypertensive patient population
Authors: Nederfors Tommy , Dahlöf Carl
Published: October 2007

Secretion rates and composition of unstimulated and chewing–stimulated whole saliva and 3% citric acid stimulated parotid and submandibular‐sublingual secretions were studied in 12 hypertensive patients during withdrawal of and re‐exposure to antihypertensive pharmacotherapy. All the patients' blood pressures were well controlled by monotherapy with metoprolol, a β1‐selective adrenoceptor antagonist. Blood pressure measurements and saliva sampling were performed at about 9.30 a.m., 2 h after intake of breakfast, on days 0 (medicated baseline), 7, 14, 28 (nonmedicated experimental values and nonmedicated baseline) and 35 (medicated experimental values). A significant increase in unstimulated whole saliva secretion rate was observed when metoprolol was withdrawn and a corresponding decrease when the drug was reintroduced. A positive correlation was found between diastolic blood pressure levels and chewing‐stimulated whole saliva secretion rates. In unstimulated whole saliva and 3% citric acid stimulated submandibular‐sublingual secretion, the output of total protein, amylase, potassium, calcium and phosphate was significantly increased during the withdrawal period and decreased when metoprolol was reintroduced. For chewing‐stimulated whole saliva, the corresponding changes were restricted to output of total protein and amylase while for citric acid stimulated parotid secretion, no changes in salivary composition were observed. Finally, in all secretions one or both of the ratios hexosamine/total protein and sialic acid/total protein were affected, indicating a possible effect of (J‐adrenoceptor antagonists on salivary protein synthesis.
A comparative study of the transition between predentin and dentin, using various preparative procedures in the rat
Authors: Goldberg Michel , Septier Dominique
Published: October 2007

The appearance of the junction between predentin and dentin of rat incisors was investigated after chemical fixation (aldehyde), physical fixation (high pressure freezing and freeze substitution) and by histochemistry. Physical fixation revealed a 1–2 urn wide intermediary zone, in which only the collagen fibers were mineralized. In dentin, which looked denser and more homogeneous, both collagen fibers and intercollagen‐ous spaces were mineralized. The intermediary layer could not be seen after aldehyde fixation. When cationic dyes were used during fixation in order to retain proteoglycans, a 0.5–5 μm border zone located at the junction between predentin and dentin was densely stained on the dentin side, whereas in dentin only the interglobular network displayed electron density. The periodic acid‐thiocarbohydrazide‐silver proteinate reaction, visualizing glycoproteins, and the phosphotungstic acid/chromic acid mixture, which reveals glycoproteins and phosphorylated proteins, produced extensive staining of the transitional zone located at the dentin edge, whereas staining was weaker in dentin. These morphological and histochemical investigations support the existence of an intermediary zone in which mineralization occurs. This transitional zone between predentin and dentin has specific properties; therefore we propose it be termed metadentin.
Expression of c‐erbB‐2 protein in keratinocytes of oral mucosal lichen planus and subsequent squamous cell carcinoma
Authors: Kilpi Anu , Rich Alison M. , Konttinen Yrjö T. , Reade Peter C.
Published: October 2007

Oral mucosal lichen planus (OMLP) is a well recognized mucosal disease with unknown etiology. Considerable controversy exists as to whether OMLP is intrinsically premalignant, or if the disorder facilitates the development of oral mucosal squamous cell carcinoma (OMSCC) by external factors. The aim of the present study was to investigate the expression of c‐erbB‐2 protein in the keratinocytes of initial biopsies of oral mucosal disorders diagnosed as OMLP with no evidence of epithelial dysplasia. and to compare the results with the expression of c‐erbB‐2 protein in subsequent biopsies obtained from the same patients. These results were compared with the findings from control groups (patients with dysplasia with no evidence of OMLP, patients with OMSCC with no evidence of OMLP and normal oral mucosa). The expression of the c‐erbB‐2 protein was evaluated by immunohistochemical staining of the gene product with the avidin‐biotin‐complex method using paraffin‐embedded tissue sections. Five of the initial biopsies from patients with OMLP expressed the c‐erhB‐2 protein and one did not. None of the OMLP cases that subsequently showed evidence of dysplasia expressed the c‐erhB‐2 protein, and of the three OMSCC specimens from the patients with OMLP. two were negative and one expressed c‐erbB‐2 protein. The specimens from the control groups all expressed the c‐erhB‐2 protein. The results indicated the probability of the absence of c‐erbB‐2 staining being an indication of a potential for neoplastic transformation in OMLP with dysplastic changes.
Modification of the proteoglycans of rat incisor dentin – predentin during in vivo fluorosis
Authors: Hall Rachel C. , Embery Graham , Waddington Rachel J.
Published: October 2007

Proteoglycans (PGs) were isolated from the dentin–predentin of fluorotic and control rat incisor teeth using demineralization in EDTA, followed by extraction with 4 M guanidinium chloride in the presence of protease inhibitors. Differences in the behaviour of fluorotic and control PG were evident during purification by anion exchange chromatography on Q‐Sepharose and MONO‐Q interfaced with fast protein liquid chromatography. The PG from fluorotic teeth exhibited a more anionic profile, due to changes in glycosaminoglycan characteristics, since no apparent differences were evident between the respective core proteins, both of which were 45 kDa. The constituent glycosaminoglycan chains of fluorotic dentin were of lower molecular size and showed the additional presence of dermatan sulfate and heparan sulfate by comparison to non‐fluorotic controls, where only chondroitin‐4‐sulfate was detected.
Toxicity parameters for cytotoxicity testing of dental materials in two different mammalian cell lines
Authors: Schweikl Helmut , Schmalz Gottfried
Published: October 2007

The present study compares three specific toxicity parameters for cytotoxicity testing of chemically different dental materials. Two glass ionomer cements, a zinc phosphate cement, and a composite material were used to evaluate the sensitivity of three assays: two viability assays, the MTT assay and the quantifiable neutral red assay, and a proliferation assay based on the determination of the total protein content of a cell culture. The colorimetric assays were carried out using transformed mouse fibroblasts (L‐929 cells) and fibroblasts derived from biopsies of normal human gingiva. In most cases. all colorimetric assays detected much weaker cytotoxic responses, if any in gingival fibroblasts than in L‐929 cells. The viability assays indicated cytotoxicity of the extracts of two glass ionomer cements in L‐929 cells when the materials were set at 0% relative humidity for 24 h. The severe cytotoxicity of the zinc‐phosphate cement in both viability assays was less influenced by the setting conditions. The cytotoxicity of the composite material was most pronounced in the neutral red assay. In general, both the MTT assay and the neutral red assay were more sensitive than the colorimetric proliferation assay. These assays can be performed very effectively; only few cells are needed for rapid, reliable and inexpensive screening purposes of a large number of samples in a short time. Automated processing with a microplate reader after non‐radioactive labeling of the cells and subsequent automated analyses of original data, with no need for sophisticated and expensive equipment, are additional advantages of the systems.
Effect of propanal and diacetyl on quantity of remaining double bonds of chemically cured BisGMA/TEGDMA resins
Authors: Peutzfeldt Anne , Asmussen Erik
Published: October 2007

The aim of the present study was to determine the effect of propanal and diacetyl addition on the quantity of remaining double bonds of chemically cured dental resins. Propanal (propionaldehyde) or diacetyl (2.3‐butanedione) was added to monomer mixtures, which were then made chemically curable. The monomer mixtures were varied with respect to content of propanal or diacetyl. Addition of propanal or diacetyl to chemically curable resins resulted in a decrease in the quantity of remaining double bonds from 19.6% to 1.9% and from 19.6% to 11.4%, respectively. A negative correlation of statistical significance was found between content of propanal and quantity of remaining double bonds, while the relationship between content of diacetyl and quantity of remaining double bonds was found not to be linear. Propanal was equally effective in reducing the quantity of remaining double bonds in chemically cured and in the light cured resins studied previously. As regards diacetyl, a more pronounced effect on quantity of remaining double bonds was noted for light cured resins as compared with chemically cured resins. The most likely common reaction mechanism of propanal and diacetyl seemed to be that of chain transfer reactions. Furthermore, analysis of the data indicated a possible additional photoinitiating function of diacetyl.
Elevated cortisol levels in whole saliva in HIV infected individuals
Authors: Enwonwu Cyril O. , Meeks Valli I. , Sawiris Peter G.
Published: October 2007

Free cortisol concentrations in unstimulated whole saliva samples, collected at 10.00 to 11.00 h, from 23 unmedicated HIV‐positive patients and 14 control subjects were measured by radioimmunoassay. Mean cortisol level (nmol/l ± SD) was significantly higher in the HIV patients than in control subjects (27.4±9.3 vs. 10.1±3.5). Two HIV patients with pseudomembranous candidiasis had the highest saliva cortisol concentrations (mean of 48.5 nmol/l). Two other HIV patients (one with Kaposi's sarcoma and the other with periodontitis) had a mean cortisol value of 29.9 nmol/l. The possibility of plasma contamination of whole saliva in the HIV patients with inflammatory oral mucosal lesions notwithstanding, our findings suggest an increased oral burden of cortisol in both the asymptomatic and symptomatic HIV‐infected individuals. Glucocorticoids cause immunosuppression, provide selective growth advantage to various microorganisms including the fungi, and enhance replication or reactivation of latent viruses (e.g. EBV, CMV. Kaposi's sarcoma‐associated herpes viruses). Our findings suggest a need to evaluate the relevance of endogenous glucocorticoid excess in blood and saliva to the causation of some major AIDS‐associated oral lesions such as candidiasis. Kaposi's sarcoma, oral hairy leukoplakia and necrotizing gingivitis.
Human glandular salivas: their separate collection and analysis
Authors: Veerman E. C. I. , van den Keybus P. A. M. , Vissink A. , Amerongen A. V. Nieuw
Published: October 2007

Human saliva is secreted by the three pairs of major salivary glands (parotid, submandibular, and sublingual), and numerous minor ones, e.g. labial, buccal and (glosso)palatine glands. Using individually adapted collection devices, sublingual. submandibular, parotid and palatine secretions of five individuals were collected and analyzed. Electrophoretic analysis revealed that each type of saliva possesses characteristic features, despite interindividual variations. Parotid salivas are characterized by intensely staining amylase and proline‐rich protein bands, but contain minute amounts of cystatins. lysozyme and the extra‐parotid glycoprotein. Sublingual salivas are characterized by high concentrations of both types of salivary mucins. MG1 and MG2, and contain relatively high levels of lysozyme. Submandibular salivas contain highest concentration of salivary cystatin S. Palatine secretions contain high molecular weight mucins and a relatively high amylase concentration.
Microradiography and confocal laser scanning microscopy applied to enamel lesions formed in vivo with and without fluoride varnish treatment
Authors: Øgaard Bjørn , Duschner Heinz , Ruben Jan , Arends Joop
Published: October 2007

Abstract The aim of the present investigation was to combine 2 techniques suitable for lesion characterization: quantitative microradiography (TMR) and confocal laser scanning microscopy (CLSM) on in vivo induced lesions with and without a fluoride varnish (Duraphat®) treatment. Orthodontic bands were attached to premolars to be extracted for orthodontic reasons to induce enamel caries on the buccal surfaces. In the caries development part of the study, 1 tooth of each pair received at the start 1 topical application with the fluoride varnish Duraphat®, the contralateral tooth serving as untreated control. All teeth were extracted after 4 weeks. In the caries progression part, the premolars were banded for 4 weeks without any treatment to induce caries. 1 premolar in each pair was then extracted and analyzed. The contralateral tooth received one Duraphat® application and was extracted after another 2 weeks. In the caries development part of the study. TMR analysis showed that the Duraphat® treatment on sound enamel reduced lesion depth by 48% compared to the untreated control. In the caries progression part, no significant difference was found between the untreated teeth extracted after 4 weeks and the fluoride treated lesions extracted after another 2 weeks. CLSM images agreed well with the TMR measurements. In the fluoride treated lesions, the CLSM images showed more light scattering indicating precipitation of material.
A 3‐year clinical study of tunnel restorations
Authors: Strand Gunhild Vesterhus , Nordbø Håkon , Tveit Anne Bjørg , Espelid Ivar , Wikstrand Knut , Eide Geir Egil
Published: October 2007

Tunnel restorations (n=161) performed by 4 dentists were evaluated after a mean of 35 months in situ. Demineralized enamel was to be spared during preparation. The preparations were filled with a cermet glass ionomer (polyalkenoate) cement. Evaluation was carried out using clinical and radiographical criteria. During the observation period, approximately 16% of the restorations were replaced due to caries in dentin and 14% due to marginal ridge fracture. Cavitation in the approximal surface and/or increased radiolucency of the approximal enamel were observed in 34% of the remaining tunnel‐restored teeth. A significantly higher frequency of failures were registered when treating patients with a high caries activity, where the initial lesion was large, and where the restoration did not reach the approximal surface.
Effect of xylitol on dentin formation in molars of adult rats
Authors: Tjäderhane Leo , Hakala Pia , Mattila Pauli , Svanberg Martti , Larmas Markku
Published: October 2007

A xylitol‐induced reduction in dentin formation has been observed in molars of post‐weanling rats, but the effect in older animals with a slower rate of secondary dentinogenesis has not been investigated. We examined the effects of different concentrations of dietary xylitol on dentinogenesis in molars of young adult rats. The control group received a commercial basal diet, while for the other 3 groups, the same diet was supplemented with 5. 10 and 20% of xylitol. After 8 weeks, dentin thickness beneath the main fissures in the mandibular 1st and 2nd molars was measured. The final body weights did not differ between the groups. Dentin formation in the 1st molars of the 10 and 20% xylitol groups was significantly lower as compared to the controls, whereas no difference was found between these 2 groups. In conclusion, dietary xylitol reduces dentin formation in young adult rats in spite of the slow rate of dentinogenesis.
Reasons for the caries decline: what do the experts believe?
Authors: Bratthall Douglas , Hänsel‐Petersson Gunnel , Sundberg Hans
Published: October 2007

The aim of this paper was to describe what experts of today believe are the main reasons explaining the caries decline seen in many westernized countries over the past 3 decades. We have collected the views of a number of international experts, trying to answer the specific question “What are the main reasons why 20‐25‐year‐old persons have less caries nowadays, compared to 30 years ago?”. A questionnaire was mailed to 55 experts with a number of thinkable explanations to be scored according to a predetermined scale. The 25 items were divided into main groups under the heading of diet, fluorides. plaque, saliva, dentist/dental materials and other factors. The experts were asked to think of a specific country or area, and also to specify whether the chosen area had water fluoridation or not. The main finding of our study, based on a 95% response rate, was that there is a very large variation in how the experts graded the impact of various possible factors. For the use of fluoride toothpaste, there was a clear agreement of a definite positive effect.
Factors for changes of caries prevalence among adolescents in Germany
Authors: Splieth Christian , Meyer Georg
Published: October 2007

Data on caries prevalence among adolescents in East and West Germany before and after unification (1990) were compared with changes in etiologic and preventive parameters. The postwar increase of total sugar consumption resulted in an increase of caries prevalence among adolescents in both East and West Germany until 1970. Parallel to the introduction of preventive measures, especially systemic fluoridation, the national caries level in East Germany stabilized at 4–5 DMFT (in 13–14–year–olds) with significant regional differences. The introduction of fluoridated toothpaste after 1973 in West Germany was followed by a caries decline in children (1970s) and in adolescents (1980s) from very high caries levels (8.8 DMFT in 13–14–year–olds in 1983) to moderate levels (5.1 DMFT in 1989). The sudden increase from 10% to 90% fluoridated toothpaste in East Germany in 1990 was also accompanied by a caries decline in adolescents. Group prevention, which included fluoride varnish programs and the introduction of free prevention (brushing instructions, fluoridations. sealants) at private dentists for 6–19–year–olds since 1983. seems to be responsible for the latest caries reductions all over Germany.
Changes in caries prevalence in Japan
Authors: Miyazaki Hideo , Morimoto Motoi
Published: October 2007

In Japan, the mean DMFT at 12 years of age increased from 2.8 in 1957 to 5.9 in 1975. From the 1981 survey (DMFT=5.43), conversely, the mean DMFT decreased and reached 3.64 in 1993. The increase in caries prevalence can, without doubt, be explained by an increment of sugar consumption, since the intake of sugar increased after World War II and exceeded 18.25 kg/year (50 g/day) in 1965 and reached a maximum value (29.3 kg/year) in 1973 in Japan. On the other hand, the reason why the DMFT has decreased since 1981 is not clear. In many industrialized countries, a caries reduction has been achieved with acceptable fluoride exposure, although sugar consumption was still at a high level. However, fluoride usage was still limited during the last 2 decades in Japan. There is no community where fluoridated drinking water has been supplied since 1972. Fluoride tablet use was also discontinued for children in the 1970s. Fluoride mouthrinsing programs were available for only 19r of school children in 1992. Moreover, the market share of fluoridated dentifrices stayed at 10% until 1986 and became 30% only in 1988. An excellent correlation (r=0.91; P 0.01) is observed between the DMFT in 12‐year‐olds and per capita sugar consumption per year between 1957 and 1987 in Japan.
Monitoring the caries process Optical methods for clinical diagnosis and quantification of enamel caries
Authors: Angmar‐Mansson B. , AI‐Khateeb S. , Tranaeus S.
Published: October 2007

Early detection of a caries lesion would enable the dentist, by using effective prophylactic measures, to enhance remineralization and conservation of the tooth substance rather than restoration of the dentition. The presently‐used diagnostic methods of detecting early lesions require visual observation. Reflected light is used to detect changes in color, texture, and translucency of the tooth substance. Attempts to improve the traditional methods or to develop new ones have been numerous. For clinical use, only 2 quantitative methods are presently available: (i) a method based on the scattering of light by enamel crystals in relation to their surrounding environment, and (ii) a method that uses visible laser light within the blue‐green region as the light source to excite the autofluorescence of enamel. The possibilities and limitations of these methods are evaluated, and clinical applications are presented and discussed.
Developmental dental defects associated with long breast feeding
Authors: Alaluusua Satu , Lukinmaa Pirjo‐Liisa , Koskimies Marjukka , Pirinen Sinikka , Hölttä Päivi , Kallio Markku , Holttinen Tiina , Salmenperä Leena
Published: October 2007

Despite its unequivocal advantages, breast feeding may be associated with undesired side‐effects. Recently, we have shown an association between exposure via mother's milk to dioxins and developmental defects of the child's teeth. The present study was undertaken to analyze further the association between the duration of breast feeding and the occurrence of dental defects. For this purpose, 2 different populations were selected. The first population comprised 40 children who had mineralization defects in the permanent 1st molars, and their age‐, living area‐ and sex‐matched controls. The median duration of breast feeding was 9 months in the affected children compared to 6 months in the controls. The defects were more extensive after prolonged breast feeding. The second population consisted of 97 children whose mothers had been encouraged to extensive and prolonged breast feeding. Of these children, 24 had mineralization defects. They all had been breastfed longer than 8 months. In both study populations mineralization defects were associated with the duration of breast feeding. The result suggests that long breast feeding may increase the risk of mineralization defects in healthy children, possibly because of environmental contaminants that interfere with tooth development.
Increased caries prevalence in 2.5‐year‐old children with cleft lip and/or palate
Authors: Bokhout B. , Hofman F. X. W. M. , van Limbeek J. , Kramer G. J. C. , Prahl‐Andersen B.
Published: October 2007

The prevalence of dental caries was determined clinically in 2.5‐year‐old Dutch cleft lip and/or palate children (n=76) and in children without congenital malformation (n=75). The parents were given a structured questionnaire regarding the child's dietary habits, oral hygiene, fluoride exposure and social economic background. The prevalence of dental caries was higher in children with oral cleft than in children without oral cleft. Initial caries (white spots) was diagnosed in 17.1% of the subjects with oral cleft compared with 4.0% of the control subjects. Manifest caries (cavities) was found in 26.3% of the children with oral cleft compared with 5.3% of the controls. The dft score (manifest caries) was significantly higher for the oral cleft group (0.59±1.35) than for the control group (0.11±0.54). 52% of the total number of initial and manifest lesions were localized to the maxillary incisors. A multivariate analysis yielded initial caries, oral hygiene and treatment with preoperative infant orthopaedics as the variables significantly associated with manifest caries.
Acid anion profiles in dental plaque following consumption of cereal‐based foods and fruits
Authors: Pollard M. A. , Higham S. M. , Curzon M. E. J. , Edgar W. M.
Published: October 2007

The aim of this study was to investigate the acid anions produced in plaque after chewing various cereal‐based foods and fruits for one minute. Test foods were oranges, apples, bananas, Cornflakes®. Branflakes®, Weetabix®. Alpert®. white bread, wholemeal bread, rice and spaghetti, plus positive and negative controls of 10% sucrose and 10% sorbitol. 4 males and 3 females, aged 22–37 years, participated in the study. 7 min from the start of chewing. 48‐h plaque was collected from all accessible smooth surfaces, with no attempt to collect interproximal plaque, and centrifuged. Plaque fluid was withdrawn and analyzed by isotachophoresis for formate, succinate, lactate. acetate and propionate. At rest, acetate was the major anion present in plaque fluid, whereas following carbohydrate consumption, highest levels of lactate were detected followed by acetate. The amount of lactate only, detected in plaque fluid, was significantly correlated to the carbohydrate present in the food. It was concluded that important information regarding the acidogenicity of test foods is gained by studying the acid anion profile of plaque fluid.
Prevention of etretinate‐induced craniofacial malformations by vitamin B6in the rat
Authors: Jacobsson Catharina , Granström Gösta
Published: October 2007

The preventive effect of vitamin B6 on etretinate‐induced malformations in pregnant Sprague‐Dawley rats was studied. The etretinate‐induced malformation was produced by intraperitoneal administration of 10 mg/kg etretinate at embryonal day 8.5. Vitamin B6 was administered as intramuscular injections at embryonal day 7.5 and 8.5. Vitamin B6 reduced the number and severity of facial clefts, micrognatia. meningocele. microtia and blood vessel anomalies. It is suggested that vitamin B6 induces suppressive effects on etretinate‐induced teratogenesis when administered before or at the same time as the teratogen.
Effect of surface coatings on flexural properties of glass ionomers
Authors: Miyazaki Masashi , Moore B. Keith , Onose Hideo
Published: October 2007

The purpose of this study was to investigate the change in flexural strength and fracture toughness of light‐cured glass ionomer cements after long‐term immersion in water, and to investigate the effect of surface coatings on their properties. 2 resin‐modified and 1 conventional glass ionomer cements were employed. For the flexural strength, a 25×2×2 mm stainless steel mold was used. For the fracture toughness (KIC). single edge notch specimens with dimensions 25×2.5×5 mm and a 0.5 mm notch (a/W=0.5) were prepared in a stainless steel mold. Specimens were subjected to the 3 point bending at 0.5 mm/min after storage in 37°C water for the periods of 1 h, 24 h, 1 wk. 1 month, and 6 months. The glass ionomer cements tended to exhibit an increase in mechanical properties over the 24‐h period and then to maintain a constant strength. The surface protection of the resin‐modified glass ionomer cement has some effect on the mechanical properties during early setting reactions, and it is desirable that the cement should be protected from direct water contact for at least 1 h after cement mixing.
Hypnosis compared with group therapy and individual desensitization for dental anxiety
Authors: Moore Rod , Abrahamsen Randi , Brodsgaard Inger
Published: October 2007

Effects of hypnotherapy (HT) and self–hypnosis training on extreme dental anxiety in adults aged 19–65 years were compared with group therapy (GT) and individual desensitization (SD) using scales of dental anxiety, dental beliefs, and fear of a next dentist (after specialist treatment). All experimental groups were demographically comparable and showed reduced anxiety and improved dental beliefs compared with 51 control patients. The 25 HT patients did not differ significantly in numbers of dropouts during training compared with the 30 GT patients or 68 SD patients. For patients completing treatment. HT (n=22) reduced dental anxiety to the same degree as GT (n=24) and SD (n=60). HT and SD patients required more therapist hours per patient than did GT, but total dropouts at 1 yr after specialist treatment were significantly greater in HT (13/25) than for SD rehearsals (5/34) or SD video (8/32). but not GT (15/30). Hypnotizability was found to vary from patient to patient, with a direct relationship to time saved. But hypnotizability had an inverse relationship to STAI general anxiety level for those who went on to dentists after 1 year. Transference effects were noted for most HT dropout patients as an aversive response to continued dental treatment with other dentists than the specialist.
Absence of binding of human salivary glycoprotein to human gingival fibroblast‐like cells in vitro
Authors: Zentner Andrej , Heaney Thomas G.
Published: October 2007

The aim of this study was to determine whether human high molecular weight salivary glycoprotein binds in vitro to human gingival fibroblastlike cells. Primary monolayer cultures of 2 human gingival fibroblastlike cell lines were incubated with a high molecular weight fraction of salivary glycoprotein which expressed blood group A activity and glycoprotein‐cell binding probed using an FITC‐conjugated mouse monoclonal antibody to human blood group A antigen. Surface fluorescence of protein‐treated cells was found to be no greater than that of untreated or serum‐treated control cultures. As significant binding of salivary glycoprotein to gingival fibroblast‐like cells does not occur in vitro, saliva‐mediated inhibition of fibroblast attachment to hydroxyapatite is not dependent on specific ligand‐lectin interactions.
X‐ray diffraction study of crystalline phases of calcium sulphate in alginate impression materials
Authors: Anastassiadou V. , Dolopoulou V. , Kaloyannides A.
Published: October 2007

In the present study the crystalline phases of calcium sulphate present in various commercially available alginate impression materials were identified by means of x‐ray diffraction. The diffractograms obtained indicated that the predominant crystalline phase in most materials was calcium sulphate dihydrate and confirmed the presence of calcium sulphate hemihydrate in some products.
Localized juvenile periodontitis and Actinobacillus actinomycetemcomitans in a Brazilian population
Authors: Tinoco Eduardo Muniz Barretto , Beldi Maria Ines , Loureiro Carlos Alfredo , Lana Marcia , Campedelli Flavia , Tinoco Neyde Muniz Barretto , Gjermo Per , Preus Hans Ragnar
Published: October 2007

Localized juvenile periodontitis (LJP) has been used as a model for studying periodontal disease, and its prevalence is considered to be higher in third‐world countries (0.3–8%) than in industrialized countries (0.1%). Mostly, the disease has been associated with Actinobacillus actinomycetemcomitans (A.a.) but lack of association has also been reported. The aim of this study was to identify LJP patients in geographically different Brazilian populations and assess the presence of A.a. in their periodontal lesions. 7843 children, 12–19–years of age, from the cities of Rio de Janeiro, Votorantim and Belo Horizonte were screened, and LJP patients were identified by strict clinical and radiographical criteria. A final LJP prevalence of 0.3%, with a 99% confidence interval between 0.16%) to 0.47%, was found. The prevalence in the subpopulations varied between 0.1–1.1% in the different areas. Subgingival bacterial samples were obtained from the oral cavity of 25 patients and their family members. 80% of these patients, 39.5% of their family members, 35.3% of their parents, and 43.9% of all siblings were culture positive for A.a. All but one of the families had at least one member in addition to the patient who was culture positive for A.a. In 3 families, >1 member showed radiographic and clinical signs of LJP. 30% of non‐LJP subjects coming from one of the areas with higher LJP prevalence harbored A.a. We conclude that LJP is highly associated with A.a. in this Brazilian population.
Effect of exposure time on in vitro caries diagnosis using the Digora® system
Authors: Huysmans Marie‐Charlotte D. N.J.M. , Hintze Hanne , Wenzel Ann
Published: October 2007

The aim of this study was to determine the in vitro diagnostic performance for approximal caries and occlusal dentine caries diagnosis of the Digora® system for digital radiography in relation to the exposure time. Radiographs were made of 220 extracted human posterior teeth and cuspids at exposure time levels of 3%, 6%, 10%, 20%, and 78% of the exposure time needed for E‐speed film (image sets I, II, III, IV, and V, respectively). The image sets were put in random order (III, I, IV, II, V) and assessed independently by 3 observers using a 5–point confidence scale. True caries status was determined histologically after sectioning of the teeth. Evaluated parameters were: interexaminer κ, sensitivity, specificity, Dz3/4 (the distance of one operating point to the diagonal in the ROC domain) and area under the ROC curve. The Spearman correlation coefficients between the parameters and both exposure time and order of viewing of the sets were calculated. For approximal surfaces, the ranges of mean parameter values were: sensitivity 26–33%, specificity 93–95%, Dz3/4 0.63–0.84, area 0.61–0.69. For occlusal surfaces, the ranges were: sensitivity 52–60%, specificity 91–95%, Dz3/4 1.03–1.34, area 0.79–0.87. Out of 24 pairwise comparisons between sets V and I, 5 were significant. Out of 24 comparisons between set V and II, only 2 were significant. It was concluded that diagnostic performance is unlikely to be impaired for an exposure time as short as 6% of E‐speed film exposure. When reducing the exposure time to 3% of E‐speed film exposure, caries diagnosis may be impaired.
Effects of chlorhexidine on the bacterial colonization and degradation of dentin and completely demineralized dentin in situ
Authors: van Strijp A.J.P. , van Steenbergena T.J.M. , ten Cate J.M.
Published: October 2007

The effects of 0.2% chlorhexidine on selected plaque microorganisms were studied in an intraoral dentin caries model. In 8 individuals wearing partial dentures, sound and completely demineralized dentin specimens were placed consecutively in 2 periods of 4 weeks, respectively. Throughout the experimental period, the specimens were treated 2 × daily with 0.2% chlorhexidine; control specimens were treated with water. Plaque accumulation on the specimens was left undisturbed. No protection against demineralization of the dentin or degradation of the dentin collagen by the chlorhexidine treatment was observed. The chlorhexidine treatment did not result in a reduction of the total cultivable flora when compared with the control specimens. A significant reduction of mutans streptococci and total streptococci recovered from completely demineralized dentin treated with chlorhexidine was observed, but the proportions of Actinomyces and lactobacilli were not affected significantly. It is speculated that areas of exposed roots, which are difficult to reach by oral hygiene measurements, such as approximal surfaces, will not be protected by a 0.2%) chlorhexidine mouthrinse against the caries process.
Immunocompetent cells in rat periodontal ligament and their recruitment incident to experimental orthodontic tooth movement
Authors: Vandevska‐Radunovic Vaska , Kvinnsland Inger Hals , Kvinnsland Steinar , Jonsson Roland
Published: October 2007

The aims of this study were to evaluate the number and distribution of immunocompetent cells in normal rat periodontal ligament (PDL) and to quantify their recruitment incident to experimental tooth movement. 27 young animals had the 1st right maxillary molar moved mesially by an orthodontic appliance for 1, 3, 7 and 14 days, respectively. 4 animals served as untreated controls. An immunohistochemical procedure was carried out on alternate serial cryostat sections, and monoclonal antibodies against CD1 II (macrophages, dendritic cells), CD43+ (lymphocytes, polymorphs), CD4 (helper T‐lymphocytes), and class II MHC molecules were used. Mean counts of the immunolabeled cells in the control group showed the highest number of GDI lb+ and class II molecule expressing cells, while CD4+ and CD43+ cells were scarcely found. Significant increase in the number of CD1 lb+, CD43+ cells and class II molecules was found in the PDL of the experimentally moved 1st molars compared with the contralateral side and the control group, while CD4+ cells showed no significant increase. CD11b+ and cells expressing class II molecules were found around hyalinized tissue, between dentin and cellular cementum and close to Malassez'epithelial cells. In conclusion, normal rat PDL has high number of macrophage and dendritic‐like cells, but few lymphocytes and granulocytes. Furthermore, experimental tooth movement leads to significant recruitment of cells belonging to the mononuclear phagocytic system, but has no significant effect on the number of lymphocytes and granulocytes in the rat PDL.
Effect of platelet‐derived growth factor‐BB on bone formation in calvarial defects: an experimental study in rabbits
Authors: Vikjasr Daniel , Blom Søren , Hjorting‐Hansen Erik , Pinholt Else Marie
Published: October 2007

The effect of recombinant human platelet‐derived growth factor‐BB (rhPDGF‐BB) on bone healing was examined in calvarial defects in rabbits. Bicortical circular (critical size) defects were prepared in the calvarial bone of 16 rabbits. The defects were closed on the dural side and covered externally with expanded polytetrafluoroethylene membranes to prevent interference with osteogenesis within the defect by the surrounding tissue and to keep the growth factor in place. A single dose of methylcellulose gel (4.4%) with (n= 8) or without rhPDGF‐BB (50/jg/ml) (n= 8) was applied to the defects, and the bone formation was evaluated after 8 weeks. Healing of detects in both groups was characterized by the presence of newly formed bone along the edges of the original defect and by a central area of fibrous connective tissue. The newly formed bone in the rhPDGF‐BB treated defects had a trabecular structure; in contrast, a more compact structure was found in the control defects. In the rhPDGF‐BB‐treated defects, the bone ingrowth was 51.8 ± 7.1% compared to 30.5 ± 3.3% in the control defects. Furthermore, the amount of mineralized tissue was increased 112% in the rhPDGF‐BB group. The amount of bone marrow was increased 75% in the rhPDGF‐BB‐treated defect. The porosity of cortical lamella in the newly formed bone was 84% higher in the rhPDGF‐BB‐trealed defects compared to the control. These results show that administration of a single dose of rhPDGF‐BB stimulates bone formation in critical size calvarial defects.
A computer‐assisted videodensitometric method to visualize mineral distributions in in vitro and in vivo formed root caries lesions
Authors: Inaba Daisuke , Takagi Okiuji , Arends Joop
Published: October 2007

A computer‐assisted videodensitometry (CAV) method is presented for the microradiographical mineral determination and mineral visualization of in vitro and in vivo formed dentin lesions. The method employs as essential steps (1) image digitizing by a CCD camera, (2) conversion of gray values to equivalent aluminium thicknesses and (3) conversion of aluminium thickness to vol% of mineral. Procedure and accuracy are described. The CAV method is illustrated for dentin lesions formed in vitro as well as for clinical root caries lesions. The CAV method is especially advantageous for clinical lesions because it can be employed for very complex mineral distributions and irregular lesion outlines. In given areas of interest, the mineral distribution (in vol%) can be plotted in 3D form in pseudo‐colors. Conventional micro radio graphical profiles can be obtained directly from the CAV images. For in vitro lesions, the mineral distribution parameters, lesion depth, mineral loss, and mineral acquisition values can be generated from CAV images with a reproducibility of better than 7%. The CAV method is a valuable tool in quantitative mineral studies of clinical lesions in extracted teeth as well as in situ lesion investigations.
Resin‐modified glass ionomer cements: fluoride release and influence on Streptococcus mutans growth
Authors: Friedl Karl‐Heinz , Schmalz Gottfried , Miller Karl‐Anton , Shams Mohammad
Published: October 2007

The aims of the present study were to measure the fluoride release of 1 glass ionomer cement, 1 cermet cement, 3 resin‐modified glass ionomer cements and 1 compomer, and to determine the influence of each material on bacterial growth. Test specimens were eluted in saline for 180 days. Every 2 days, the specimens were transferred into fresh saline and the fluoride content of the solution was measured. Furthermore, 48‐h, 14‐d, 90‐d, and 180‐d eluates were inoculated with Streptococcus mutans and bacterial growth was recorded nephelometrically. Fluoride release dropped significantly over time for each material with values between 6.2 (Ketac‐Silver) and 29.3 (Photac‐Fil) ppm after 48 h to values between 0.6 (Ketac‐Silver) and 1.7 (Ketac‐Fil, Vitremer) ppm after 180 days. Each material reduced bacterial growth at each time of examination, but the effect decreased significantly over time with a maximum growth of 71.7% (Ketac‐Fil) to 85.6% (Ketac‐Silver) after 48 h and 94.7 (Vitremer) to 99.0% (Ketac‐Silver) after 180 days (growth control = 100%). Both Ketac‐Silver and Dyract showed a significantly lower inhibiting effect on bacterial growth than the other materials. The tested materials showed a good correlation between fluoride release and influence on bacterial growth. However, both effects dropped dramatically over the 180‐days period.
Epithelium‐fibroblast co‐culture for assessing mucosal irritancy of metals used in dentistry
Authors: Schmalz Gottfried , Arenholt‐Bindslev Dorthe , Hiller Karl‐Anton , Schweikl Helmut
Published: October 2007

No valid animal or in vitro model exists to assess the potential mucosal irritancy of dental materials. However, recently, a commercially available model system based on a recombined co‐culture of human fibroblasts and human epithelial cells has been introduced for evaluating the time‐dependent irritancy of cosmetic products. Cell viability and prostaglandin E2 (PGE2) release from the cells were used as markers for the irritative potential of test materials. The objective of the present study was to evaluate the suitability of this model for monitoring the irritative potential of metals and cast alloys used in dentistry. The human fibroblast‐keratinocyte co‐cultures were exposed to test specimens fabricated from copper, zinc, palladium, nickel, tin, cobalt, indium, a high noble cast alloy, and from a dental ceramic. Cell survival rates decreased after exposure to copper (14–25%), cobalt (60%), zinc (63%), indium (85%), nickel (87%), and the non‐oxidized and oxidized high noble cast alloy (87%/90%) compared to untreated control cultures. Dental ceramic, palladium and tin did not influence cell viability. In parallel, the PGE2 release was continuously monitored up to 24 h using a competitive displacement enzyme immunoassay. PGE2 release increased most highly in the cultures exposed to copper (6–25 fold), cobalt (7 fold), indium (4 fold), and zinc (2 fold) compared to untreated control cultures. The PGE2 determination proved to be a non–destructive method for continuous monitoring of cell reactions in the same culture. The model used seems promising for evaluating the time‐dependent mucosal irritancy of dental cast alloys.
Short Communication Motor activity in sleep bruxism with concomitant jaw muscle pain. A retrospective pilot study
Authors: Lavigne Gilles J. , Rompré Pierre H. , Montplaisir Jacques Y. , Lobbezoo Frank
Published: October 2007

In a controlled polysomnographic (PSG) study that we recently performed in our laboratory, we noticed that some patients with a chief complaint of sleep bruxism reported concomitant non‐myofascial pain in their masticatory muscles. To study the influence of such pain on the pattern of bruxism motor activity, we re‐assessed the 2nd out of 2 consecutive PSG and masseter electromyographic (EMG) recordings of 7 bruxers without pain and 6 bruxers with concomitant jaw muscle pain. Among others, the selection of these patients was based on reports of current jaw muscle pain intensity, using 100‐mm visual analogue scales. In our sample of bruxism patients with pain, levels of pain intensity did not differ significantly between bedtime and awakening in the morning. Although there were no significant differences between both subgroups of bruxers in the number of bruxism bursts per episode and the root‐mean‐squared EMG level per bruxism burst, bruxers with pain had 40% less bruxism episodes per hour of sleep. This suggests that non‐myofascial jaw muscle pain decreases the number of initiations of bruxism episodes, but leaves their contents unaffected.
Dental anxiety among adolescents in St. Petersburg, Russia
Authors: Bergius Marianne , Berggren Ulf , Bogdanov Oleg , Kakeberg Magnus
Published: October 2007

This small‐size epidemiologic investigation examined the prevalence and etiology of dental fear and anxiety among 288 schoolchildren aged 13–18 years in St. Petersburg, Russia. The adolescent population was collected from a larger sociological investigation performed in Russia during the early period of reforms. The investigation revealed a comparatively elevated anxiety level with an average DAS score of 10.0 and a prevalence of high dental fear of 12.6%. The present study showed that the origin of dental anxiety as reported by adolescent, urban Russians parallels much of previous results from the US and Western Europe. Thus, the etiology of dental anxiety was related to negative dental experiences and this conditional learning seemed to be especially prevalent in the presence of previous oral pain experiences and an existing dental anxiety in the family.