bluuebunny/crossref_metadata_2025 huggingface dataset:
Sleeping positions and dental arch dimensions in children with suspected obstructive sleep apnea syndrome
Authors: Pirilá Kirsi , Tahvanainen Paula , Huggare Jan , Nieminen Peter , Löppönen Heikki
Published: October 2007

The present paper analyzed the association between children's sleeping positions and dental arch morphology. The sleeping patterns of 27 children, aged 3 to 10 yr, suspected of having the obstructive sleep apnea syndrome (OSAS) were studied by polysomnography (PSG) and videotape recordings under laboratory conditions. The PSG recordings were used to calculate the apnea index (AI) and the relative time spent sleeping on the back, and the videotapes to categorize distinctly different sleep and head postures. Plaster casts were made for the assessment of dental arch morphology. Sleeping predominantly on one's back, was associated with a reduced maxillary intercanine width, while prolonged head extension during sleep correlated inversely with the overjet. The subjects with the highest AI scores (>4) had larger dental arches. We suggest that sleeping on the back causes a more posterior tongue position, reducing its moulding effect on the anterior dental arch. As nasopharyngeal airway obstruction in OSAS‐patients might trigger an anterior tongue position to secure a free airway passage, there will be increased lingual pressure on the dental arches, leading to their dimensional increase.
Casting of TI‐6AI‐4V alloy compared with pure Ti in an Ar‐arc casting machine
Authors: Syverud Morten , Okabe Toru , Herø Håkon
Published: October 2007

Dental protheses of Ti are normally cast in pure Ti. Some appliances, however, require higher yield strength. Casting of Ti alloys is of interest in such cases. The objective of the present work was to study the quality of castings made of Ti‐6A–4V compared with those made of pure Ti. Casting was made into a mold kept at room temperature using a MgO‐Al2O3 investment. A standardized five‐unit bridge was cast, consisting of two cylindrical crowns with sharp margins and three pontics. The overall mold filling was satisfactory. The margins of the casting alloys were, however, more rugged and incomplete than those of pure Ti. The most likely reason for this difference is the increased formation of dendrites in the alloy and thus more resistance to fluid flow. Furthermore, the sprue of the alloy was also found to contain some spherical, internal pores. Such pores were rare in the pure Ti castings. The surface reactions were found to be minimal for both of the materials. Increased casting deficiencies observed in the cast bridges of the Ti‐6AI‐4V alloy, compared with pure Ti, were: 1) the margins of the crowns in the bridge were less complete and 2) there was a tendency to an increased internal porosity, particularly in the sprues.
Multivariate analysis of fears in dental phobic patients according to a reduced FSS‐II scale
Authors: Hakeberg Magnus , Gustafsson Jan‐Eric , Berggren Ulf , Carlsson Sven G.
Published: October 2007

This study analyzed and assessed dimensions of a questionnaire developed to measure general fears and phobias. A previous factor analysis among 109 dental phobics had revealed a five‐factor structure with 22 items and an explained total variance of 54%. The present study analyzed the same material using a multivariate statistical procedure (LISREL) to reveal structural latent variables. The LISREL analysis, based on the correlation matrix, yielded a chi‐square of 216.6 with 195 degrees of freedom (P=0.13S) and showed a model with seven latent variables. One was a general fear factor correlated to all 22 items. The other six factors concerned “Illness & Death” (5 items). “Failures & Embarrassment” (5 items), “Social situations” (5 items), “Physical injuries” (4 items). “Animals & Natural phenomena” (4 items), One item (opposite sex) was included in both “Failures & Embarrassment” and “Social situations”. The last factor, “Social interaction”, combined all the items in “Failures & Embarrassment” and “Social situations” (9 items). In conclusion, this multivariate statistical analysis (LISREL) revealed and confirmed a factor structure similar to our previous study, but added two important dimensions not shown with a traditional factor analysis. This reduced FSS – II version measures general fears and phobias and may be used on a routine clinical basis as well as in dental phobia research.
Longitudinal study of incisal tooth wear in children and adolescents
Authors: Silness John , Berge Morten , Johannessen Gerd
Published: October 2007

This report was derived from a longitudinal study of the development and progress of incisal tooth wear in children and adolescents. The study group was established in 1991/1992 and consisted of 79 participants between 8 and 15 yr. They were reexamined in 1993 and the time span between the first and second examination was 12–14 months. Assessment of incisal Wear was made on stone casts based on silicone impression material according to the Incisal wear Index (IwI). The index used was shown to have good reproducibility. The results showed that the pattern of incisal wear had been maintained during the observation period. Prevalence and severity of incisal wear had increased significantly with age. The strength of the suggested linear relationship between age and incisal wear decreased during the observation period. At the same time the growth increments of wear, ΔIwI, were negatively correlated with age, indicating that the progression of incisal wear slowed down with increasing age. Description of the true relationship between age and incisal wear outside the age range represented in the sample must await the results of forthcoming studies.
Effect of xylitol‐containing chewing gum on sorbitol metabolism in dental plaque
Authors: Assev Synnøve , Rølla Gunnar
Published: October 2007

The aim of the present study was to examine whether a long‐term use of chewing gum with xylitol as the only sweetener would affect sorbitol metabolism in dental plaque. Ten test subjects used xylitol‐sweetened chewing gum for 12 weeks. Plaque was collected at three occasions; 1) Control plaque; 2) Test plaque I: plaque collected after 12 weeks of chewing xylitol‐containing chewing gum; 3) Test plaque II: sucrose‐stimulated plaque collected 2 d after Test plaque I was collected. Plaque suspensions were incubated with [14C]sorbitol, and uptake of sorbitol and production of sorbitol metabolites were determined by HPLC. Plaque formation and sorbitol uptake were significantly reduced.
Effect of unilateral masticatory function on craniofacial growth in the rabbit
Authors: Poikela Aila , Kantomaa Tuomo , Tuominen Marja , Pirttiniemi Pertti
Published: October 2007

In this study the main purpose was to investigate the effect of altered masticatory function on the shape and inclination of the articular surface of the glenoid fossa, and on the growth of the mandible in the rabbit. The maxillary and mandibular molars of 14, 10‐d‐old rabbits were ground down to the gingiva on the right side twice a week; 9 were controls. At age SO d all rabbits were killed, soft tissue of the heads was removed, and the measurements were made. The inclination of the articular surface of the glenoid fossa was shallower on both sides in the experimental group than in the controls; the difference was greater on the right side. There were dimensional and angular differences between right and left sides of the mandible and maxilla in the experimental animals. In conclusion, unilateral masticatory function was found to cause an asymmetric craniofacial growth. Furthermore, function has an effect on the shape of the glenoid fossa, especially on the balancing side, in conjunction with asymmetric function.
Interfacial gaps of resin cemented ceramic inlays
Authors: Sorensen John A. , Munksgaard Erik Christian
Published: October 2007

A method was developed for measuring presence, location and extent of interfacial contraction gaps of resin‐cemented ceramic inlays in dentin cavities. Cylindrical ceramic inlays were cemented using one of 12 commercially available resin composite cements to make film thickness of 200‐μm. Cross‐sections revealed absence of marginal gaps but contraction gaps occurred at all dentin‐cement interfaces at the cavity floors and ranged from 1.6 to 7.1 μm. This was equivalent to 0.8‐3.5% of the cement film thickness and was 3‐10 times greater than the wall‐to‐wall contraction in percent observed when resin composites are used as filling materials in 3‐5 mm butt‐joint dentin cavities. The results support the theory that contraction gaps developing adjacent to thin films of resin cements reach size equivalent to the cement film thickness multiplied by the volumetric polymerization shrinkage of the cement.
Differential diagnosis of odontophobic patients using the DSM‐IV
Authors: Moore R. , Brødsgaard I.
Published: October 2007

Categories of extreme anxiety for dental treatment were derived using, DSM‐IV psychiatric criteria. A sample of 40 men and 40 women patients with extreme dental anxiety were initially evaluated with Dental Anxiety Scale (DAS), Trait Anxiety Inventory (STAI‐T) and Geer Fear Scale (GFS). Patients all had DAS scores ≥15 indicating extreme dental anxiety and were further evaluated with clinical interviews, Denial Fear Survey (DPS), Dental Beliefs Survey (DBS) and Mood Adjective Checklist (MACL). Results showed that 46% of 80 patients complained mainly of powerlessness and embarrassment about dental treatment while also having greater DBS scores than other categories, i.e. social phobia. Another 19% reported conditioned specific phobias (pain, drilling, injection, etc.) most often and lower DBS and GFS scores than other groups; while 35% had broader general anxiety complications, such as multiple phobias and agoraphobia with or without general anxiety symptoms (higher GFS and STAI‐T compared to others). Symptoms of general anxiety disorder (GAD) were present in 30 of 80 patients, who had greater STAI‐T and GFS and lower MACL scores than non‐GAD patients. These results have implications for appropriate treatment strategies.
Determination of temporomandibular joint fluid concentrations using vitamin B12 as an internal standard
Authors: Alsteirgren Per , Appelgren Anna , Appelgren Bjorn , Kopp Sigvard , Luncteberg Thomas , Theodorsson Elvar
Published: October 2007

The aim of the investigation was to test the reproducibility and accuracy of a new method to measure temporomandibular joint (TMJ) fluid concentrations of various substances by saline washing, using exogenous B12 as a marker. An in vitro test was first performed with glucose as a lest substance. The difference between a B12‐calculated and known standard concentration of glucose was very small. Saline washing of the TMJ was performed on 13 patients having signs of TMJ arthritis, and the aspirates obtained were analyzed for neuropeptide Y‐like immunoreactivity (NPY‐LI) and interleukin‐lβ (IL‐1β). Vitamin B12 was mixed with the saline immediately before injection, and a sample of the aspirate was later compared photometrically with the injection solution. There were positive correlations between saline aspirate and joint fluid concentrations for NPY‐LI and IL‐1β, and the correlations were stronger for saline aspirates with high joint fluid content. This study shows that the method is reliable for measurement of joint fluid concentrations of various substances, such as NPY‐LI and IL‐Iβ.
Effect of specimen preparation method on relative volume of the microvasculature – a light microscopic study in rat tongue
Authors: Selliseth Nils J. , Olsen Hugo C. , Selvig Knut A.
Published: October 2007

The study of corrosion casts by scanning electron microscope is an established means of investigating three‐dimensional microvascular architecture. However, concern has been raised that the volume of the vasculature is affected by the perfusion procedure. Ten rats (group A) were standard perfusion fixed, while 10 rats (group B) were perfused with acrylic resin after fixation. Vascular volume was assessed by computer‐aided analysis of thin sections of tongue lamina pro–pria. The results showed that vascular volume in lamina propria of rat tongue is 13.6±4.1 % (mean±SD). No significant differences in vascular volume were found between group A and group B specimens. It can be concluded that plastic‐perfused specimens may be as reliable as histologic sections in obtaining a true image of vascular systems. Thus, corrosion casts are suitable for histometric analysis of the microvasculature.
Effects of delmopinol on antimicrobial peroxidase systems and lysozyme in vitro and in human whole saliva
Authors: Tenovuo Jorma , Hannuksela Satu , Lenander‐Lumikari Marianne
Published: October 2007

Delmopinol is a new surface‐active agent which can reduce plaque formation and gingivitis. This study was aimed to analyze whether delmopinol (0.0032–0.65 mM) interferes with the activity of two surface‐active oral antimicrobial enzymes, salivary peroxidase and lysozyme. In addition to human whole saliva (pH 5.0 and 6.0), the experiments were done in 0.1 M phosphate buffer (pH 6.0) with purified laetoperoxidase (LPO) and myeloperoxidase (MPO). LPO and MPO were significantly inhibited in buffer by delmopinol concentrations >6.5 mM and 3.2 mM, respectively. No such inhibition was found for total peroxidase activity in mixed saliva. In vitro, delmopinol was found to desorb surface‐bound peroxidases in an active form to the liquid phase. In further analyses, the possible effect of delmopinol on peroxidase‐generated hypoihiocyanite (HOSCN/OSCN−) was studied in saliva and buffer. No effect was found in buffer, but salivary HOSCN/OSCN declined significantly with 6.5 mM delmopinol. This was obviously due to an enhanced decay of hypothiocyanite. rather than its reduced rate of formation. No deimopinol‐related inhibition of lysozyine occurred in saliva or buffer. The results suggest that high concentration (6.4 mM – 0.2 %) of delmopinol may lower the concentrations of antimicrobial HOSCN/OSCN− in saliva but has no effect on human lysozyme.
Mutans Streptococci and dental caries prevalence in a group of Latvian preschool children
Authors: Köhler Birgitta , Bjarnason Sibilla , Care Ruta , Mackevica Inese , Pence Inguna
Published: October 2007

Paraffin‐stimulated saliva samples were collected from 140 children 3‐ and 4‐yr old attending nine nursery schools in Latvia. The salivary levels of mutans streptococci were rated from zero to 3 after being cultured on a commercially available strip selective for these microorganisms. Of the children, 29.3% were rated at zero (∼104 cfu per ml saliva). This group of children demonstrated the lowest mean caries prevalence dmfstot= 1.5 (SD 1.9). The highest dmfstot was found among children in class 2 (38.6%; %105‐106 cfu/ml) and class 3 (12.1% >106 cfu/ml) with a mean caries prevalence of 6.5 (SD 5.8) and 6.4 (SD 6.0), respectively. The study demonstrates the association between high caries prevalence and high salivary levels of mutans streptococci in the young child. It is suggested that early identification of mutans streptococcicolonized children might be of value in selecting at caries risk children for preventive measures.
The influence of the position of surface recording electrodes on the relative uptake of the masseteric and temporal M‐responses in man
Authors: Macaluso Guido Maria , De Laat Antoon
Published: October 2007

The present report aimed at evaluating the influence of recording conditions on the relative uptake of direct motor responses obtained in the masseter and tempo‐rails muscles after electrical stimulation of their nerves, using a monopolar needle technique. In 10 subjects, various surface electromyographic recording set‐ups were compared using supramaximal M‐responses. Volume‐conducted potentials originating from the masseter muscle could be recorded from the neck. For the masseter muscle, the optimal position for the active recording electrode was over the anterior and inferior part of the muscle belly. The configuration of the masseter M‐response recorded from various positions over the muscle belly was highly variable both intra‐ and interindividually. The configuration of the M‐response of the anterior part of the temporalis muscle showed less variability.
Expression of the α‐subunit of CR4(CD11c) by peripheral blood and crevicular fluid neutrophils
Authors: Mouynet P. , Genetet N. , Plcot C. , Apiou J. , Nicolas P. , Michel J.F.
Published: October 2007

This work determined the levels of expression of CD11c by neutrophils (PMNs) collected from subjects with various periodontal conditions. The percentages of GDI Ic‐positive crevicular fluid PMNs were significantly lower than those of peripheral blood PMNs, but the levels of CD11c expression were similar in PB‐PMNs and CF‐PMNs (P<0.001). On the other hand, no significant difference could be found between the groups, either for the percentages of CD11c‐positive cells or for the CD11c expression levels.
Oral mucosal desquamation caused by two toothpaste detergents in an experimental model
Authors: Herlofson Bente Brokstad , Barkvoll Pål
Published: October 2007

Sodium lauryl sulfate (SLS), the most widely used detergent in toothpastes, has been reported to cause adverse effects on oral soft tissues. This double‐blind cross‐over study describes the oral mucosal effects of SLS‐containing toothpastes and pastes containing a zwitterionic detergent, cocoamidopropyl‐betaine (CAPB) in an experimental model in 28 healthy females. Seven toothpastes, differing only in detergent concentration and/or type, were used: SLS (0.5, 1.0, 1.5%), CAPB (0.64, 1.27, 1.90%) and a placebo. Each participant applied 1 cm of assigned test toothpaste via a cap splint to the teeth and the mucosa of the upper jaw. The splints were used twice daily for 2 min during a period of 4 d, after which the participants were examined for oral desquamation. No other oral hygiene was allowed during the test periods. Ten days brushing with a detergent‐free toothpaste was performed between each test period. Forty‐five desquamative reactions were observed in 21 of 27 subjects (one was excluded) during the trial. Forty‐two reactions were recorded during the SLS periods and the remaining three during the CAPB periods. The detergent‐free toothpaste did not result in oral desquamation. SLS in toothpastes significantly increased the incidence of desquamation of the oral mucosa compared with toothpastes containing the detergent CAPB. The model used is not directly relevant to normal toothbrushing with toothpaste, but indicates that sensitive patients may contract mucosal irritation through SLS in toothpastes. Less toxic detergents, e.g. CAPB, are desirable in oral hygiene products.
Characterization of new periodontal and endodontic isolates of spirochetes
Authors: Dahle Ulf R. , Tronstad Leif , Olsen Ingar
Published: October 2007

Gas chromatographic analysis of cellular fatty acids (CFA), biochemical reactions, electrophoresis of soluble cellular proteins, as well as immunodiffusion were used to discriminate between 16 fresh spirochete isolates from periodontal and endodontic infections. CFA patterns were compared by the Hewlett Packard MIDI library to all available reference strains, and results of the biochemical tests were compared to VPI's records for treponemal strains. The electrophoretograms of soluble proteins of the fresh isolates were compared to those of previously well described strains of Treponema denticola, T. pectinovorum, T. vincentii, T. socranskii subsp. socranskii, T. socranskii subsp. paredis, T. socranskii subsp. buccale, and T. socranskii 04. Immunodiffusion was carried out by using adsorbed polyclonal rabbit antibodies to representative strains of the species mentioned. These methods separated most clinical strains from approved species strains, suggesting that new species had been isolated.
Mercury vapor release from dental amalgam in patients with symptoms allegedly caused by amalgam fillings
Authors: Berglund Anders , Molin Margareta
Published: October 2007

The aim of this study was to determine whether a group of patients with symptoms, self‐related to their amalgam restorations, experienced an exposure to mercury vapor from their amalgam restorations that reached the range at which subtle symptoms have been reported in the literature. Furthermore, the aim was to determine whether the mercury exposure for these patients was significantly higher than for controls with no reported health complaints. The symptom group consisted of 10 consecutively selected patients from a larger group, referred by their physicians for investigation into any correlation between subjective symptoms and amalgam restorations. The control group consisted of 8 persons with no reported health complaints. The intra‐oral release of mercury vapor was measured between 7:45 a.m. and 9:00 p.m. at intervals of 30–45 min. following a standardized schedule. The mercury levels in plasma, erythrocytes, and urine were also determined. The calculated daily uptake of inhaled mercury vapor, released from the amalgam restorations, was less than 5% of the daily uptake calculated at the lower concentration range given by the WHO (1991), at which subtle symptoms have been found in particularly sensitive individuals. The symptom group had neither a higher estimated daily uptake of inhaled mercury vapor, nor a higher mercury concentration in blood and urine than the control group. The study provides no scientific support for the belief that the symptoms of the patients examined originated from an enhanced mercury release from their amalgam restorations.
Photodynamic therapy of oral cancer A review of basic mechanisms and clinical applications
Authors: Nauta Jan M. , van Leengoed Henricus L. L. M. , Star Willem M. , Roodenburg Jan L. N. , Witjes Max J. H. , Vermey Albert
Published: October 2007

Photodynamic therapy (PDT) is an experimental cancer treatment modality. PDT is based on the accumulation of a photosensitive dye in premalignant and malignant lesions. A certain period of time after the dye has been administered, tumor tissue may contain more of the sensitizer then the surrounding normal tissues. When tissue containing the sensitizer is exposed to light of a proper wavelength and dose, a photochemical reaction between sensitizer and light will occur. The activated photosensitizer reacts with available oxygen which subsequently damages cells and eventually may cause necrosis of the tumor. Photosensitizers can also be used for fluorescence detection. If a tumor contains more of the photosensitizer than the surrounding normal tissue, its fluorescence can potentially be utilized to detect tumors. Analogous to PDT, this can therefore be referred to as photodynamic detection (PDD). This paper reviews the basic mechanisms and clinical applications of PDT and PDD. Emphasis is placed on PDD and PDT with the photosensitizer Photofrin for detection and treatment of premalignant epithelial lesions and squamous cell carcinomas of the oral mucosa.
Prevalence of dental erosion and the implications for oral health
Authors: Nunn June Heather
Published: October 2007

The literature on dental erosion is made up of a number of areas, some of which are reviewed here: there are anecdotal case reports, linking a small number of clinical cases with a possible etiogical factor. The second area of evidence concentrates on case control studies in which there is a strong association with dental erosion, for example, patients with bulimia. The final piece of epidemiological evidence is beginning to emerge as prevalence studies, but the information from prevalence data worldwide is scanty. It is difficult to compare prevalence studies because of the different indices used in the various studies and also because of the different teeth assessed in the sample. Standardization of indices used would overcome some of these differences as would the reporting of results in a comparable way. However, identifying the true prevalence of erosion per se is fraught with difficulty because there may be more than one etiological factor operating and attrition and or abrasion may complicate the picture, especially in older populations. Case reports frequently associate evidence of erosion with excessive use of particular drinks or foodstuffs so they must be viewed with caution. There is an increasing awareness, amongst the dental profession, of the potential for this particular form of tooth wear to occur. It is important that the dental team is vigilant and instigates preventive measures before tooth tissue loss becomes clinically significant. The importance of erosion in dental health promotion should not be overlooked.
Dental erosion, summary
Authors: ten Gate J. M. , Imfeld T.
Published: October 2007

Although reports on dental erosion have always appeared in the dental literature, there is currently a growing interest among researchers and clinicians. Potential risk factors for dental erosion are changed lifestyle and eating patterns, with increased consumption of acidic foods and beverages. Various gastrointestinal and eating disorders expose the dentition to frequent contacts with very acidic gastric content, which may lead to erosion. Whether these factors indeed lead, on a population scale, to a higher prevalence and incidence of erosion is yet to be established. This article summarizes the different aspects of the prevalence, pathology, etiology, assessment, prevention and treatment of dental erosion, and concludes with recommendations for future research.
Galvanic corrosion and cytotoxic effects of amalgam and gallium alloys coupled to titanium
Authors: Bumgardner Joel D. , Johansson Berit I.
Published: October 2007

The aim of this study was to examine and compare the galvanic corrosion of a conventional, a dispersed high‐copper, and a palladium‐enriched spherical high‐copper amalgam and a gallium alloy coupled to titanium in saline and cell culture solutions, and to evaluate the effects of the couples on cultured cells. The potentials and charge transfers between amalgams and titanium were measured by electrochemical corrosion methods. Cytotoxicity of the couples, as indicated by the uptake of neutral red vital stain, was determined in 24‐h direct contact human gingival libroblast cell cultures. Results of this study indicated that before connecting the high‐copper amalgams to titanium, the amalgams exhibited more positive potentials which resulted in initial negative charge transfers, i.e. corrosion of titanium. However, this initial corrosion appeared to cause titanium to passivate, and a shift in galvanic currents to positive charge transfers, i.e. corrosion of the amalgam samples. Lower galvanic currents were measured for the amalgam‐titanium couples as compared to the gallium alloy‐titanium couple. Coupling the conventional or the palladium‐enriched high‐copper amalgams to titanium did not significantly affect the uptake of neutral red as compared to cells not exposed to any test alloy. However, significant cytotoxic effects were observed when the dispersed‐type high‐copper amalgam and the gallium alloy were coupled to titanium. Even though the corrosion currents measured for these couples were less than gold alloys coupled to amalgam, these results suggest there is the potential for released galvanic corrosion products to become cytotoxic. These data warrant further investigations into the effects of coupling amalgam and gallium alloys to titanium in the oral environment.
Three‐point bending strength of ceramics fused to cast titanium
Authors: Pröbster Lothar , Maiwald Uwe , Weber Heiner
Published: October 2007

Titanium requires special ceramic systems for veneering. This study compared the three‐point bending strength of three commercially available titanium ceramic systems with a NiCr‐alloy with conventional ceramics. Three‐point bend specimens 25 × 5 × 0.5 mm were cast from polyethylene patterns. After α‐case removal, they were veneered with 8 × 5 × 1 mm of ceramics at the center of the bar. Specimens were tested in a universal testing machine without ageing, after thermocycling, and after 90 d storage in an electrolyte solution. Titanium‐ceramic systems were found to have a significantly lower bond strength in comparison to the NiCr‐ceramic system. One of the titanium ceramic systems had a significantly lower bond strength in comparison to the other systems investigated. It could be concluded that bonding between titanium and ceramics is obtainable; however, the achievable bond strengths did not match the NiCr‐ceramic control.
Variations in fibrinolytic activity of human whole saliva
Authors: Majerus Patrick , Dalcette Benoit , Hermans Marh , Pourtois Michel , Capel Paul
Published: October 2007

The physiological variations of fibrinolytic activity (FA) in saliva were investigated in a population of 149 healthy volunteers including 12 pregnant women. An increase in FA could be observed with increasing age. Marked variations were observed during daytime with a peak value early in the morning. Higher FA values were observed in males as compared with females in the 20‐39 yr age group. A clear decrease in FA was observed during pregnancy. A significant correlation existed between FA and suspended epithelial cell concentration, which seemed responsible for most of the physiological FA variations. It was concluded that age, sex, pregnancy, and the time of the day are important for salivary FA and should be taken into account in any study on salivary FA related to physiological or pathological processes.
Plaque fluoride and mutans streptococci in plaque and saliva before and after discontinuation of water fluoridation
Authors: Seppä Liisa , Hausen Hannu , Kärkkäinen Sakari
Published: October 2007

Our aim was to compare plaque fluoride and the level of mutans streptococci in saliva and plaque before and 1 and 2 years after discontinuation of water fluoridation in Kuopio, Finland. For comparison, a low‐fluoride community was included in the study. Pooled plaque and saliva were collected from a random sample of 12‐year‐olds in both communities (n=139). Enumeration of mutans streptococci in plaque was made on MSB agar and the level of salivary mutans streptococci was measured using the Strip mutans® method. Fluoride was analyzed using a fluoride specific electrode. Caries, gingival status, fluoride varnish applications and self‐reported oral health habits were recorded at baseline. Before discontinuation of fluoridation. the level of mutans streptococci in saliva was significantly lower in the fluoridated than in the non‐fluoridated community. The difference in plaque mutans streptococci was not statistically significant. After discontinuation of water fluoridation, there was a significant shift towards elevated values of salivary mutans streptococci in the fluoridated community, but the level of mutans streptococci in plaque remained at the baseline level. There was no significant difference between the communities in the fluoride content of plaque either before or after discontinuation of fluoridation. From the background factors, only caries scores (higher in the non‐fluoridated community) and oral hygiene (better in the non‐fluoridated community) were significantly different between the communities.
Influence of temperature on the co‐adhesion of oral microbial pairs in saliva
Authors: Bos Rolf , van der Mei Henny C. , Busscher Henk J.
Published: October 2007

Coaggregation (interactions between two planktonic microorganisms) and co‐adhesion (interactions between sessile and planktonic microorganisms) are believed to be important factors in the formation of dental plaque by many investigators, although others doubt whether coaggregation and co‐adhesion occur in vivo. It is known that coaggregation and co‐adhesion generally occur equally well in buffer as in saliva, but the influence of temperature on the co‐adhesion of coaggregating oral microbial pairs in saliva is unknown. Therefore, co‐adhesion of streptococci suspended in saliva to glass with adhering actinomyces present (1.0x106 cells cm−2) was studied in a parallel plate flow chamber in the temperature range from 22°C to 40°C. In the range from 22°C up to 35°C both pairs studied. Streptococcus oralis 34 with Actinomyces naeslundii 5951 and Streptococcus oralis J22 with A. naeslundii 5951, displayed similar co‐adhesion kinetics and co‐adhesion in a stationary end‐point, but around and above 37°C co‐adhesion almost disappeared. Hence, we conclude that co‐adhesion of coaggregating oral microbial pairs in saliva may be critically influenced by temperature, especially around the temperatures prevailing in the oral cavity.
All‐ceramic resin‐bonded bridges A 3‐dimensional finite‐element analysis study
Authors: Pospiech Peter , Rammelsberg Peter , Goldhofer Gerhard , Gernet Wolfgang
Published: October 2007

Resin‐bonded fixed partial dentures (FPD) with a metal framework have some disadvantages: a grey shimmer of the metal wings through the abutment teeth, a higher corrosion rate, and an allergenic potential of the non‐precious alloys used. The Al2O3, ceramic In‐Ceram© seems to be strong enough to serve as a framework for resin‐bonded all‐ceramic FPDs. Because of the fact that ceramic wings often don't have enough inter‐occlusal space, a new preparation design was developed. The objective of this study was to determine the influence of load orientation (45° and 60°) and the design of the interproximal connector on the stress distribution in the bridges. A 3‐dimensional finite‐element model was developed to simulate the anatomical situation. The biting force was assumed as 250 N and oriented in oro‐buccal direction. The loading‐point was palatal 1.5 mm beneath the incisal edge. It was found that stress generally increased with an angle of the biting force of 60°. A small interdental connector (3 mm height) and/or strong interdental separation resulted in stresses of up to 455 MPa (45°) or 534 MPa (60°). Less separation with rounded edges and a higher connector (4 mm) reduced the stress to 122 MPa (45°) and 143 MPa (60°). Due to an average tensile strength of In‐Ceram at 340–400 MPa. an all‐ceramic resin‐bonded FPD may only be recommended it the height of the connector could be minimum 4 mm. Rounded edges and little interdental separation are significant for stress reduction.
The caries decline: a review of reviews
Authors: Petersson Gunnel Hänsel , Bratthall Douglas
Published: October 2007

The aim of this paper is to review publications discussing the declining prevalence of dental caries in the industrialized countries during the past decades, focusing on some main conferences addressing this issue. Has there been a real decline in the prevalence of dental caries? Several excellent papers and reviews have been published, and there is a general agreement that a marked reduction in caries prevalence has occurred among children in most of the developed countries in recent decades. This fact has stimulated much debate and attempts to identify the most likely explanations for this change. The conclusion made from this review is that the various authors believe that the use of fluoride in various forms has contributed most significantly to the decline in dental caries prevalence. A number of other factors must, however, also be taken into consideration, and such factors have been extensively discussed in the various publications.
Hypothetical mortality risk associated with spiral computed tomography of the maxilla and mandible
Authors: Dula Karl , Mini Roberto , van der Stelt Paul Frans , Lambrecht Jörg Thomas , Schneeberger Paul , Buser Daniel
Published: October 2007

In the present study, dose measurements have been conducted following examination of the maxilla and mandible with spiral computed tomography (CT). The measurements were carried out with 2 phantoms, a head and neck phantom and a full body phantom. The analysis of applied thermoluminescent dosimeters yielded radiation doses for organs and tissues in the head and neck region between 0.6 and 16.7 mGy when 40 axial slices and 120 kV/165 mAs were used as exposure parameters. The effective dose was calculated as 0.58 and 0.48 mSv in the maxilla and mandible, respectively. Tested methods for dose reduction showed a significant decrease of radiation dose from 40 to 65%. Based on these results, the mortality risk was estimated according to calculation models recommended by the Committee on the Biological Effects of Ionizing Radiations and by the International Commission on Radiological Protection. Both models resulted in similar values. The mortality risk ranges from 46.2×10‐6 for 20‐year‐old men to 11.2×10−6 for 65‐year‐old women. Using 2 methods of dose reduction, the mortality risk decreased by ∼ 50 to 60% to 19.1×10−6 for 20‐year‐old men and 5.5×10−6 for 65‐year‐old women. It can be concluded that a CT scan of the maxillofacial complex causes a considerable radiation dose when compared with conventional radiographic examinations. Therefore, a careful indication for this imaging technique and dose reduction methods should be considered in daily practice.
Electrophoresis of whole‐cell soluble proteins of microorganisms isolated from bacteremias in endodontic therapy
Authors: Debelian Gilberto J. , Olsen Ingar , Tronstad Leif
Published: October 2007

We have previously demonstrated that anaerobic bacteria are the microorganisms most frequently isolated from blood following endodontic therapy of teeth with apical periodontitis. Phenotypic characterisation of the isolates suggested that the bacteria in the blood originated from the root canal. The present experiment using sodium dodecyl sulfate‐polyacrylamide gel electrophoresis (SDS‐PAGE) was carried out in an effort to verify these findings, and to further study the microorganisms involved in endodontic bacteremias. Soluble cellular proteins were extracted from 11 reference strains and 26 bacterial isolates recovered from the root canal and blood. These included Propionibacterium acnes, Peptostreptococcus prevotii, Fusobacterium nucleatum, Prevotella intermedia, Actinomyces israelii, Streptococcus intermedius, Streptococcus sanguis. The electrophoretic patterns mostly confirmed the identity of the isolates as determined by the biochemical and antimicrobial resistance tests. Furthermore, with this typing method the species Prevotella intermedia and Prevotella nigrescens could be differentiated. These species had been recovered from both root canal and blood. Also, differences between subspecies of Fusobacterium nucleatum became evident with SDS‐PAGE, and the results indicated that the organism recovered from the root canal and blood was Fusobacterium nucleatum subsp. vincentii. The electrophoretic patterns of the different organisms isolated from the root canal and the blood were similar, providing further evidence that the bacteria found in the blood originated from the root canal.
Effect of cortical perforations of both graft and host bed on onlay incorporation to the rat skull
Authors: Alberius Per , Gordh Monica , Lindberg Lisbeth , Johnell Olof
Published: October 2007

The mechanisms involved in the integration of autogeneic bone grafts still attract much interest due to their clinical importance. The purpose of this study was to obtain data on the effects of a combination of cortical bone perforations both at the recipient site and the inner layer of a bicortical graft. 12 adult rats obtained femoral or tibial bicortical bone grafts from isogeneic donors to the tibia, one on each leg. On the experimental side, both the recipient bed and the inner cortical graft layer received multiple perforations (0.25 mm in diameter), while on the control side, only perforations of the recipient cortical bed were made. The findings were assessed by routine histology and immunohistochemical analysis for some bone and cartilage matrix proteins after 4 and 20 weeks. The combined cortical perforations of the graft and the host bed induced a locally improved bony incorporation of the graft and a corticalization of the graft marrow, implying improved mechanical stability. The graft height persistence was similar between groups. Intense labelling of the bone matrix proteins was apparent in all bone tissue and by diversified intensity at its various components, demonstrating ongoing remodeling activities. PRELP and fibromodulin mainly outlined the soft tissues surrounding the graft and compact bone sealing off the graft marrow. Immunolabelling contributed a more delicate picture of the mechanisms involved in graft incorporation.
Facilitated diffusio1n by iontophoresis of vasoactive agents to the rat incisor pulp
Authors: Kostouros George D. , Olgart Lelf , Gazelius Bertil , Edwall Lennart
Published: October 2007

The use of iontophoresis for facilitated diffusion of vasoactive agents into the dental pulp was investigated in lower incisor teeth of anaesthetized rats. Acetylcholine, carbachol and noradrenaline were iontophoresed with anodal and sodium nitroprusside with cathodal direct current through a superficial dentin exposure. Pulpal blood flow was measured with laser Doppler flowmetry. Current intensities below 100 μA of both polarities, using sodium chloride as a medium, caused no or minor afferent nerve‐induced vasodilation, but excited sympathetic fibres of the pulp in a current‐dependent manner. The current threshold for facilitated diffusion of acetylcholine was about 20 μA. The vascular responses to the cholinergic and noradrenergic drugs appeared within a minute after the onset of current and they were abolished by systemic administration of atropine and phenoxy benzamine, respectively. Iontophoresis of acetylcholine (40–100 μA for 20–120 s) caused a 3‐fold increase of pulpal blood flow which was not dose‐dependent; carbachol provoked a high‐magnitude, long‐lasting vasodilation and so did sodium nitroprusside. Noradrenaline caused a long‐lasting vasoconstriction. In denervated rats iontophoresis of carbachol had effects similar to those seen in intact animals. None of the drugs used locally had any effect on systemic blood pressure. The results of this study indicate that iontophoresis can be used for delivery of vasoactive agents from an exposed dentin surface into the pulp in sufficient quantity to elicit drug‐specific local vascular responses without causing systemic vascular effects.
Bonding of resin cements to a metal substrate: influence of pretreatment on the adherence energy
Authors: Asmussen Erik , Attal Jean‐Pierre , Degrange Michel
Published: October 2007

The adherence of resin cements to restoration as well as tooth structure is of prime importance for the longevity of cemented restorations. It was the aim of the study to investigate the effect of an acid and à base primer on (i) surface polarity of a nonprecious alloy and on (ii) adherence energy of resin cements bonded to the alloy. The beams were pretreated with a 3% acetone solution of either maleic acid or N,N‐diethanol‐p‐toluidine, and the solvent evaporated. The polarity was determined by means of measurements of contact angles. The adherence energy was measured by means of the wedge test, according to which 2 beams were glued together with the resin cement. A wedge was introduced between the joined beams to create a fissure, and on the basis of the length of the fissure, the adherence energy was calculated. It was found that the polar component of the surface free energy of the alloy increased as a consequence of the pretreatments. The results also showed that the pretreatments gave rise to an increase in adherence energy of 11–15 J/m2, equivalent to relative increases of 22–54%. The observed increases in adherence energy may be due to an increase in polar interactions at the interface between adhesive and substrate.
Carbon fiber reinforced root canal posts Mechanical and cytotoxic properties
Authors: Torbjörner Annika , Karlsson Stig , Syverud Morten , Hensten‐Pettersen Arne
Published: October 2007

The aim of this study was to compare the mechanical properties of a prefabricated root canal post made of carbon fiber reinforced composites (CFRC) with metal posts and to assess the cytotoxic effects elicited. Flexural modulus and ultimate flexural strength was determined by 3 point loading after CRFC posts had been stored either dry or in water. The bending test was carried out with and without preceding thermocycling of the CFRC posts. The cytotoxicity was evaluated by an agar overlay method after dry and wet storage. The values of flexural modulus and ultimate flexural strength were for dry stored CFRC post 82±6 GPa and 1154±65 MPa respectively. The flexural values decreased significantly after water storage and after thermocycling. No cytotoxic effects were observed adjacent to any CFRC post. Although fiber reinforced composites may have the potential to replace metals in many clinical situations, additional research is needed to ensure a satisfying life‐span.
Expression of collagen and elastic fibers in duct‐ligated submandibular glands of mice
Authors: Zaia Alexandra A. , Coletta Ricardo Delia , Almeida Oslei P. , Line Sergio R. P.
Published: October 2007

Atrophy of salivary glands may occur by ductal obstruction caused by calculus, infection or neoplastic processes, or as consequence of systemic diseases and aging. In the present work, we have used histochemical methods to study the expression of elastic and collagen fibers during experimental atrophy of the submandibular gland of mice. Glandular atrophy was accompanied by a rapid increase in collagen deposition in both septal and intralobular regions. The expression of elastic fibers was not significantly altered during atrophy; a discrete increase of elastic fibers was noted only around ductal structures. The results showed that experimental ductal obstruction is a useful in vivo model to study molecular events that take part in the remodeling of the extracellular matrix during atrophy of salivary glands.
Immunotoxic effects of smokeless tobacco on the accessory cell function of rat oral epithelium
Authors: Hasséus Bengt , Wallström Mats , österdahl Bengt‐Göran , Hirsch Jan‐Michaél , Jontell Mats
Published: October 2007

Smokeless tobacco (ST) is known to adversely effect the oral mucosa, but knowledge about the influence on immune defence is limited. Few studies have investigated the effect of ST on the local immune response. In the present study, we have assessed the effect of a crude Swedish moist snuff (SS) extract, alkaloids, and nitrosamines on T‐cell mitogenic response to Con A using epithelial cells, including Langerhans cells, of the rat oral mucosa as accessory cells. SS extract at a concentration of 4% reduced the T‐cell proliferation by 50% (IC50= 4%). Pretreatment of either oral epithelial cells or T‐cells with SS extract also gave a significant inhibition of T‐cell proliferation. This effect was not obtained following preincubation with SS components as alkaloids and different tobacco‐specific nitrosamines (TSNA). None of the tested compounds were found to possess any mitogenic properties. This in vitro study showed that SS extract can evoke an immunosuppressive effect on mitogen‐driven T‐cell proliferation using cells from oral epithelium as accessory cells. This effect was more pronounced when SS extract was employed compared to when the single SS components were used alone.