bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of image enhancement for detectability of bone lesions in digitized intraoral radiographs
Authors: WENZEL ANN
Published: October 2007

Abstract —Digital image enhancement is concerned with the computer‐controlled manipulation of image information. The aim of this study was to evaluate whether diagnostic accuracy would improve in digitally enhanced images of radiographs with impaired density. Each of 83 dry mandibles was divided into four regions. By random assignment it was decided for each region whether or not a hole should be drilled. Three intraoral radiographs (3x4 cm) were performed of each region. at different exposure times: 2.0 s, 0.60 s, and 0.16 s and interpreted. The radiographs were thereafter recorded by a video camera connected to an IBM‐PC. The personal computer held a hardware digitization card defined at a 512x5I2x8 matrix resolution on the basis of which a software program with image enhancement facilities was developed. The light and dark radiographs were digitally enhanced by the use of contrast stretching and smoothing filters. The light (0.16 s) original radiographs were less accurate than the ones with optimal density (0.60 s) while no significant differences were found between dark (2.0 s) and optimal density original radiographs. No significant differences were found between original and digitized radiographs of optimal density and digitally enhanced images of light or dark radiographs. The diagnostic accuracy obtained from optimal density radiographs can thus be maintained in digitized dark radiographs and in light radiographs with a four‐times dose reduction after digital image enhancement,
Silicoating: evaluation of a new method of bonding composite resin to metal
Authors: PEUTZFELDT ANNE , ASMUSSEN ERIK
Published: October 2007

Abstract — Silicoating is a new type of pretreatment of the metal in the resin‐bonded bridge technique. The size of bond strength between resin cement and silicoated metal was investigated. Different resin cements, types of metal, and grain sizes of sand used for roughening the metal surface were tested. Furthermore, the effect on the bond strength of contamination with saliva and of thermocycling was measured. There was no difference of importance between the two resin cements tested. Bond strengths obtained with Wirobond were the highest and insensible to changes in resin cement, grain size of sand, and to thermocycling. It was found that sand of the smallest grain size used brought about the highest bond strengths. Contamination with saliva did not significantly reduce the size of the bond strengths. Rinsing the metal surfaces with water or ethanol after contamination restored the bond strengths to their original magnitude. By silicoating, a greater resistance to thermocycling was obtained. Nevertheless, except for Wirobond, a fall in bond strength was measured after thermocycling. Bond strengths of the size of those between etched enamel and composite resin were measured, and the Silicoater method seems a reliable pretreatment of the metal.
Buffering effect of antacids in the mouth ‐ a new treatment of dental erosion?
Authors: MEURMAN J. H. , KUITTINEN T. , KANGAS M. , TUISKU T.
Published: October 2007

Abstract – Antacids are drugs of choice in the treatment of reflux esophagitis and peptic ulcer disease, where acid regurgitation may cause dental erosion. Since there are no specific preventive measures or effective treatment for erosions, the present study was made to assess whether the keeping of antacids in the mouth before swallowing would be beneficial with regard to their effect on mouth pH, after acidic challenge. Five healthy subjects formed the test panel. After measuring the acid binding capacity of all the antacid preparations in the Finnish market, the two most effective were selected for testing, one in emulsion form (Novaluzid), the other a tablet (Link). Acid regurgitation was mimicked by consuming a low‐pH (3.2) drink immediately before the antacid. Control series were made with the acidic drink only. Both the antacids were found to counteract totally the pH fall caused by the drink, when measured as changes in the tongue surface pH. The Novaluzid preparation was more effective than the Link preparation but the difference was not significant. It may be anticipated that patients suffering from acid regurgitations would benefit if they are counseled to keep their antacids in the mouth for a while before swallowing.
Chemically induced inflammation in rat oral mucosa
Authors: AHLFORS E. E. , LARSSON Å.
Published: October 2007

Abstract – The toxic, irritative, and sensitizing effects of topically applied sodium lauryl sulfate (SLS), dithranol triacetate (DTA), nonanoic acid in methyl‐ or propyl ester (NAM, NAP) in the buccal mucosa were investigated in a Sprague‐Dawley rat model. Semi‐quantitative evaluations of cellular infiltrates were performed in routine histologic preparations. The toxic potential was tested with 2% and 0.2% solutions. All substances, except 0.2% SLS, caused an increased cellularity, mainly of a mononuclear cell type. The low dose of NAM induced stronger inflammatory reactions than the high dose. Repeated applications of 2% solutions decreased the response compared to one application, except for NAM, where a clear irritative potential was observed. Pre‐exposure of dorsal skin prior to buccal painting resulted in an enhanced reaction to NAM and NAP, whereas no sensitizing capacity was noted in SLS or DTA in this model.
Corrosion of dental amalgam and mercury vapor emission in vitro
Authors: MOBERG LARS‐ERIK
Published: October 2007

Abstract – Amalgam specimens were immersed for 30 days in 1) water, 2) 0.9% NaCl in water, 3) 0.9% NaCl and 10 mM phosphate buffer in water, and 4) 0.9% NaCl, 7.7 mM phosphate, and 6.1 mM citric acid in water. The solutions were stored in stoppered glass tubes. Hg‐drops were immersed in solutions 1, 2, and 3. The concentration of mercury vapor in the air above the solutions was measured once a day. After 30 days the amounts of Cu, Zn, Hg, and Ag in the solutions were analyzed by atomic absorption spectrophotometry. The results showed that 0.9% NaCl alone or in combination with the additives increased the amounts of elements released into the solutions. The concentration of Hg° in the glass tubes increased with the amount of Hg in the solutions, with the exception of solution No. 3, from which significantly less Hg° evaporated. The results indicate that the composition of the saliva, oral hygiene and dietary factors may be determinants of Hg° emission from amalgams in the oral cavity.
Fluoride acquisition on and in human enamel during topical application in vitro
Authors: SAXEGAARD ERIK , RÖLLA GUNNAR
Published: October 2007

Abstract – Fluoride acquisition during topical fluoride treatment was studied after different time intervals, at different concentrations and at different pH. The effects of pretreating the enamel with Ca++, and of pre‐etching were also tested. Four experimental groups of repeated measures design were established. Chemical assessments were made of the amounts of fluoride formed on (as alkali soluble fluoride, i.e., calcium fluoride) and in enamel (as firmly bound fluoride). The depositions on enamel were also demonstrated by SEM. The amounts of alkali soluble fluoride on enamel increased with time, concentration, pH‐decrease and calcium availability. The time of exposure seemed to be the major factor. The amounts of fluoride deposited on enamel outranged by far (>70%) the amounts of fluoride acquired in the enamel. The formation of alkali soluble fluoride on enamel is probably limited by the availability of calcium ions. It is suggested that the fluoride on enamel may protect the enamel surface and serve as a reservoir of fluoride.
Gingival and mucosal reactions after intensive chlorhexidine gel treatment with or without oral hygiene measures
Authors: ALMQVIST HELÉNE , LUTHMAN JOHAN
Published: October 2007

Abstract – The aim of this study was to elucidate whether soft tissue reactions during chlorhexidine (CHX) treatment might be associated with meticulous oral hygiene measures. A commercially available 1% chlorhexidine digluconate gel (Hibitane Dental Gel) was applied in a custom tray for the mandibular arch, 10 min daily, for 14 days. A split mouth approach was used to allow evaluation of the effect of oral hygiene measures with toothbrush, toothpaste, and dental floss on one side of the arch. During the treatment period, 8 out of 12 subjects developed gingival and/or mucosal reactions appearing as white patches or ulcerations. Both the gingival reactions on the buccal marginal gingiva and the mucosal reactions near the margin of the custom tray occurred only when the gel treatment was combined with meticulous oral hygiene measures. The white patches, which could easily be detached, leaving ulcerated areas, consisted entirely of stratified squamous epithelium. The findings suggest that intensive treatment with chlorhexidine gel, in individually fitted custom trays, combined with meticulous oral hygiene measures may induce toxic effects on the surface layers of the gingiva and mucosa.
Aluminum oxalate/glycine solutions as pretreatment in the Gluma bonding system
Authors: DE ARAUJO PAULO AMARANTE , ASMUSSEN ERIK
Published: October 2007

Abstract— Dentin and enamel surfaces were treated with solutions of aluminum oxalate (AO), the pH of which was adjusted by glycine. Gluma as well as an enamel bonding agent were applied to the surfaces before the placement of a composite resin. On shear bond testing, there was obtained a strong adhesion that was influenced by the pH of the AO solutions. Dentin and enamel specimens for examination by scanning electron microscopy (SEM) were also prepared and treated as. above. Enamel specimens showed a very definite etching pattern, and on the dentin surfaces a precipitate was observed. The amount of this product seemed to decrease as the pH increased.
Radiographic control of fixture‐abutment connection in Brånemark implant technique
Authors: SEWERIN IB PAUL
Published: October 2007

Abstract— In the treatment with osseointegrated implants ad modum Brånemark a radiographic control of the fixture‐abutment connection is recommended. The purpose of the present study was to analyze the possibilities of detecting incomplete connection by radiography using the recommended technique. In an experimental model the influence of film density, orientation of the fixture hexagon, angulation between film plane and fixture axis, leakage width, and partial connection were analyzed. Slits of 0.05 mm were detectable under optimum projection conditions. On the other hand, slits of 0.1 mm were obscured even at deviations of 5°. A number of factors, e.g. low density level and “unfavorable” orientation of the hexagon in relation to the X‐ray beam, reduce the possibilities of detecting slits. It is concluded that in clinical cases a demonstration of incomplete fixture‐abutment connection by the use of the recommended radiographic technique radiography to some extent is fortuitous, and that radiographic control has certain limitations.
Ultrastructural relationship of cell envelope layers in Wolinella recta
Authors: KEROSUO EERO , HAAPASALO MARKUS , LOUNATMAA KARI
Published: October 2007

Abstract – The cell envelope of Wolinella recta was studied by electron microscopy. In thin sections the surface layer (S‐layer) seemed to be in close contact to the outer membrane (OM). A hexagonally arranged pattern of the S‐layer was revealed by freeze‐etching. Unlike in other oral bacteria with an S‐layer, the cleavage occurred along the S‐layer by freeze‐fracture, suggesting an exceptionally tight relationship between the two outermost layers. The convex surface of the S‐layer was usually revealed by this technique. When cleavage occurred through the outer membrane, no periodicity was seen in the arrangement of the intramembranous particles.
In vitro investigation of shear bond strength of a phosphate based dentinal bonding agent
Authors: HUANG GREGORY T. , SÖDERHOLM KARL‐JOHAN M.
Published: October 2007

Abstract – The objective with this study was to investigate how the shear bond strength of a phosphate based dentinal bonding agent is influenced by storage in saline at 37°C up to 6 months. The effect of dentin bonding agent on the leachability of calcium fron dentin was also determined. The results showed that the shear bond strength decreased after saline storage. After half a year, the strength was ca. 60%, of the initial dry strength. The bonding agent also accelerated the leaching of calcium from the dentin discs, a finding which was explained as being a result of acidic reactions occurring at the dentin‐bonding agent interface. In addition to the increased calcium leachability, the dentin bonding agent peeled off with time from the dentin discs. SEM investigation of the dentin surfaces after either shear strength determination or the film had peeled off due to water storage showed that a residual film was left on the dentin. This film, based on morphologic appearance, is most likely composed of the bonding agent but may also contain residuals of the smear layer.
Potentiation of fibroblast DNA synthesis by a phenytoin‐induced mononuclear cell derived factor in vitro
Authors: MODÉER THOMAS , DAHLLÖF GÖRAN , KARSTEN JOHAN , OTTESKOG PER
Published: October 2007

Abstract – Human mononuclear cells purified by Lymphoprep flotation were incubated with phenytoin (PHT) (20 μg/ml) or its metabolite p‐HPPH (2 μg/ml) in the presence of Concanaval‐in A (10 μg/ml) in vitro. The results indicate that phenytoin and its metabolite p‐HPPH induce the release of a mononuclear cell factor(s) that activates quiescent human gingival fibroblast to synthesize DNA.
Longitudinal study on the effect of early interceptive treatment in 4‐year‐old children with unilateral cross‐bite
Authors: LINDNER ANDERS
Published: October 2007

Abstract— To evaluate the results of early interceptive grinding and also the possibility of selfcorrection of unilateral cross‐bite, 76 4‐yr‐old children with this malocclusion were divided into one treated and one untreated group. In the treatment group 50% of the children exhibited a normal transverse occlusion evaluated in the mixed dentition, at the age of 9. In the untreated group only 17% showed a spontaneous correction of the cross‐bite. Among the studied dental variables the “max./mand. arch width difference” especially in the canine region was found to be a valuable predictor indicating whether cross‐bite can be successfully treated in preschoolchildren by selective grinding. The results of this study support early treatment of unilateral cross‐bite and gives the criteria whereby successful treatment by selective grinding may be expected.
Occlusal tooth contacts in natural normal adult dentition in centric occlusion studied by photocclusion technique
Authors: ATHANASIOU ATHANASIOS E. , MELSEN BIRTE , KIMMEL PHILIPPE
Published: October 2007

Abstract— The inter‐ and intraexaminer reproducibility in the interpretation of the registrations of the photocclusion technique as well as the number of occlusal contacts and their intensity in natural normal dentition in centric occlusion were studied in 20 adults. No significant differences were found regarding the inter‐ and intraexaminer interpretations for both number and intensity of occlusal contacts. A mean number of 23.8 contacts per individual, an almost symmetric and balanced distribution of the contacts between left and right sides of the dentition, and an absence of any significant differences between female and male subjects characterized the normal natural dentition.
Number of teeth, prevalence of caries and periapical lesions in insulin‐dependent diabetics
Authors: FALK HANNE , HUGOSON ANDERS , THORSTENSSON HELENE
Published: October 2007

Abstract – Ninety‐four long and 86 short duration diabetics and 86 non‐diabetics, aged 20–70 yr, participated in the study. The clinical and radiographic examination comprised recordings of the number of teeth, carious lesions, restorations, endodontically treated teeth and periapical lesions. There were no significant differences between long and short duration diabetics and non‐diabetics in the number of teeth and the total number of decayed and filled tooth surfaces (DFS %). However, long duration diabetics exhibited more decayed proximal tooth surfaces (D %) than non‐diabetics. There were no significant differences between long and short duration diabetics and non‐diabetics in the mean number of endodontically treated teeth and periapical lesions. Women with long diabetes duration, however, exhibited more endodontically treated teeth with periapical lesions than women with short diabetes duration and women without diabetes. Long duration diabetics exhibited teeth with periapical lesions to a greater extent than the other groups. On the whole, diabetics and non‐diabetics exhibited a similar caries frequency but among the diabetics there was a group of individuals who had more periapical lesions than the non‐diabetics.
Effect of sorbitol‐ and xylitol‐containing chewing gum on salivary microflora, saliva, and oral sugar clearance
Authors: WENNERHOLM KERSTIN , EMILSON CLAES‐GÖRAN
Published: October 2007

Abstract – The effect of frequent use of a sorbitol‐containing nicotine chewing gum on saliva secretion rate and buffer capacity and some oral bacteria was studied in 27 patients at a smoking cessation clinic. The effect was compared with that obtained after frequent use of a chewing gum containing xylitol in a second study in 14 subjects. The results showed that sorbitol‐containing nicotine chewing gum had no significant effect on salivary numbers of oral streptococci and lactobacilli during a 3‐month period of active chewing five times a day. Chewing on xylitol‐containing gum caused a significant decrease in salivary S. mutans after 2 months but not after 3 months. No change in secretion rate or buffer capacity was observed in the two studies. Oral sugar clearance time was reduced after 3 months with a statistically significant difference to baseline values in subjects consuming the sorbitol‐containing nicotine chewing gum.
Effect of different caries preventive measures in children highly infected with mutans streptococci
Authors: LINDQUIST BIRGITTA , EDWARD STIG , TORELL PER , KRASSE BO
Published: October 2007

Abstract – The caries preventive effect of topical application of fluoride varnish (Duraphat), ferric‐aluminum‐fluoride solution (FeAlF) and chlorhexidine gel was compared in a 2‐yr clinical study. Children with more than 106 mutans streptococci per ml saliva were selected and a total of 189 13‐yr‐old children participated in the study. The children in the fluoride groups were treated every third month with either Duraphat or FeAlF‐solution. In the chlorhexidine group children with more than 2.5 × 105 mutans streptococci per ml of saliva were treated every third month. The mean number of new decayed and filled tooth surfaces was 3.06 in the chlorhexidine group, 5.88 in the Duraphat group, 5.33 in the FeAlF group, and 6.34 in the control group. Thus supervised antimicrobial treatment can significantly reduce the incidence of dental (caries) in children with high numbers of mutans streptococci.
Surface properties and ultrastructure of Porphyromonas gingivalis W50 and pleiotropic mutants
Authors: HAAPASALO MARKUS , SHAH HAROUN , GHARBIA SAHEER , SEDDON SHAUN , LOUNATMAA KARI
Published: October 2007

Abstract – Cell surface ultrastructure and other surface properties of Porphyromonas gingivalis strain W50 and pleiotropic mutants W50/BP1 (black), W50/BR1 (brown), and W50/BE1 (beige) were studied. The percentage hydrophobicity of strains W50, W50/BP1, W50/BR1, and W50/ BE1 gradually decreased from 24 to 9. Ruthenium red stained cells studied by transmission electron microscopy revealed a layer of extracellular polymeric material of varying thickness depending on the strain. The layer was thickest in W50/BP1 (15–20 nm), strains W50 and W50/ BR1 both had a layer of 12–15 nm, while strain W50/BE1 completely lacked this layer. The results clearly showed that the hydrophobicity of P. gingivalis was related not only to the thickness of the layer but also to other factors like the composition of the capsular material, such that only strain W50/BE1, for example, showed no haemagglutinating activity. The surface properties of the pleiotropic mutants appeared to be stable characteristics as cells grown on either solid or in liquid media gave comparable results. The loss of virulence of the beige strain (W50/BE1) is probably partly due to the alteration of these surface properties. Both virulent and avirulent strains, however, possessed extracellular vesicles.
Immunoelectron microscopic study of distribution of T cell subsets in oral lichen planus
Authors: JUNGELL PETER , KONTTINEN YRJÖ T. , NORTAMO PEKKA , MALMSTRÖM MARIA
Published: October 2007

Abstract – Monoclonal anti‐CD4, anti‐CD8, and anti‐GD18 antibodies were applied in avidinbiotin‐peroxidase complex staining using a pre‐embedding immunoelectron microscopy technique. Although most of the local T cells in situ were of CD4+ subtype, local CD8+ cells generally had a lower nucleus/cytoplasm ratio and contained more cell organelles than CD4+ cells. This suggests a local activation of CD8+ subpopulation, rather than activation of the numerically predominant CD4+ cells. Topographical analysis disclosed that all lymphocytes, regardless of location, were CD18+ and that most of the CD8 + cells were located subbasally and intraepithelially, whereas CD4+ cells often occurred in small clusters deeper down in the subepithelial lymphocyte‐rich band. Furthermore, CD8+ cells were often in close contact with macrophages, whereas CD4+ cells were in some instances in direct contact with plasma cells. This indicates that CD4+ cells may be involved in T cell‐dependent B cell‐mediated immunoglobulin synthesis, whereas CD8+ cytotoxic lymphocytes and tissue macrophages may be involved in the local pathogenetic process leading to basement membrane alterations.
Cross‐sectional study of patients fitted with fixed partial dentures with special reference to the caries situation
Authors: ERICSON GUNNEL , NILSON HANS , BERGMAN BO
Published: October 2007

Abstract – The caries situation among 30 patients with fixed partial dentures was examined 3 yr after cementation of the constructions. The fit of the crowns on the abutment teeth, the size of the interproximal areas and the relation between the crown margin and the gingival margin were registered. Risk factors for caries development, such as salivary factors, microbiologic factors, oral hygiene and diet were evaluated for each patient. During the 3‐yr period 54 caries lesions occurred in 25 patients. Eleven lesions were found on abutment teeth. Two were located on the root surfaces unconnected with the crown margin (>2mm from the gingival margin), three were recurrent lesions, where the crown margin was located above the gingival margin but closer than 2 mm and six were recurrent lesions where the crown margin was located under the gingival margin. No single caries risk factor seemed to be so closely correlated to the number of caries lesions developed that it could be used alone to select of patients at risk. When the sum of the assumed negative factors was used, more caries was found among the patients with three or more factors with negative values in the group as a whole. However, predicting the development of caries in an individual case with a high degree of probability seems to be complicated. Generally speaking there was no indication that caries disease development was caused by the presence of the fixed partial denture per se.
Effect of disinfecting solutions on surface texture of alginate and elastomeric impressions
Authors: PEUTZFELDT ANNE , ASMUSSEN ERIK
Published: October 2007

Abstract – The effect of immersion in six disinfecting solutions on the surface texture of 10 impression materials was investigated. Assessment of the surface texture was based on measurement of the ability to reproduce fine detail. Impressions were taken of a roughness standard, i.e. a steel block with known roughness. After setting, the impressions were either stored at room temperature for 24 h, for control, or immediately immersed in a disinfecting agent for 60 min (in one case 10 min), and after 24 h poured with gypsum. After another 24 h, the roughness of the dies was recorded with a profilometer. Three addition‐curing silicones were left unaltered by disinfection. For the remaining seven materials, the ability of detail reproduction was changed for some of the combinations of impression material and disinfecting solution. In general, this meant a reduction of detail reproduction, but occasionally an improvement of the surface texture resulted from disinfection. Changes in surface texture were most often brought about by a solution of chlorinated trisodium phosphate. It was concluded that elastomeric impression materials reproduced fine detail better than did alginates and that both types of impression material may be immersed in specific disinfecting solutions for as long as 1 h without the surface texture being impaired.
Sample, count, identify, and store the mutans streptococci
Authors: GOMEZ ILIANA DEL RIO , BRATTHALL DOUGLAS
Published: October 2007

Abstract – According to a new method for sampling mutans streptococci, “Strip mutans”, a plastic strip is contaminated by human saliva and incubated in a selective broth. After growth the strip with adherent colonies may be dried and stored. We wanted to know for how long a time bacteria in the colonies were viable if the strips, were stored under different conditions. The survival time is important if the bacteria need to be subjected to further analyses. The results showed that the viability of the bacteria after the incubation period was at least l yr when the strips were stored frozen or frozen in glycerine. Stored dried in room temperature the survival was about 8 wk. A second part of the study aimed at identifying the colonies on strips obtained from different countries. Dried strips were sent air mail to our laboratory for biochemical and immunological analyses and the results showed that serotype/biotype c/e/f of S. mutans were most frequent but d/g S. sobrinus was also present in the samples, which came from Brazil, Greece, and Sweden. Three colonies of 213 on these strips did not grow, possibly indicating non‐mutans bacteria.
Expulsion mechanism of xylitol 5‐phosphate in Streptococcus mutans
Authors: PIHLANTO‐LEPPÄLÄ ANNE , SÖDERLING EVA , MÄKINEN KAUKO K.
Published: October 2007

Abstract – The expulsion mechanism of xylitol 5‐phosphate in Streptococcus mutans ATCC 25175 was studied using resting cells incubated in the presence of 14C‐xylitol. The expulsion appeared to be a two‐step process: xylitol 5‐phosphate was first hydrolyzed to xylitol and inorganic phosphate, and the xylitol was subsequently expelled from the cells. The dephosphorylation step appeared to be energy‐requiring and it was most likely associated with a phosphatase which was active on xylitol 5‐phosphate. Two to three successive cultivations of the cells in the presence of 6% xylitol increased this enzyme activity 4.3‐fold. These results are in accordance with the presence of an energy‐dependent xylitol 5‐phosphate cycle in S. mutans, which is regulated by exogenous xylitol.
Interindividual and longitudinal studies of amino acid composition of pellicle collected in vivo
Authors: RYKKE MORTEN , SÖNJU TORLEIF , RÖLLA GUNNAR
Published: October 2007

Abstract – The formation of the acquired enamel pellicle is due to the adsorption of salivary proteins to the enamel surface. This adsorption is assumed to be specific and is dependent on the chemical characteristics of the surface. The aim of the present study was to investigate the consistency of the chemical composition of the acquired pellicle collected in vivo. Inter‐ and intraindividual differences in the chemical composition of pellicle material were examined during 2 yr in three different individuals. The amino acid profiles obtained from pellicle analyses were compared to hydrolyzed whole saliva collected at the same time as the pellicle material. The results showed that the amino acid composition of pellicle was consistent both between and within the individuals. The amino acid profiles obtained from the analyses of the saliva samples were different from the pellicle profiles, illustrating the selective nature of pellicle formation. This supports the contention that the adsorption of salivary proteins to dental enamel is a very specific process.
Absorption of UVA light by latex and vinyl gloves
Authors: LEHTINEN RISTO , KUUSILEHTO ASKO
Published: October 2007

Abstract – UVA‐radiation can produce malignant changes in skin. When making light cured dental fillings, dentist and dental assistant, particularly on their fingers, may be exposed to UVA radiation. The latex examination gloves were able to absorb 76% of the radiation, whereas the vinyl examination gloves absorbed only 33% of the radiation. Latex gloves thus proved to give more effective protection against UVA radiation than vinyl gloves.
Prevalence of caries and salivary levels of mutans streptococci in 5‐year‐old children in relation to duration of breast feeding
Authors: ALALUUSUA SATU , MYLLÄRNIEMI SINIKKA , KALLIO MARKKU , SALMENPERÄ LEENA , TAINIO VELI‐MATTI
Published: October 2007

Abstract – 144 children with a known breast feeding history were studied for their caries prevalence and level of salivary mutans streptococci. 19% of the children were exclusively breastfed for more than 9 months and 38% of the children were weaned after the age of 12 months (max. 34 months). The results of the study showed an equal caries prevalence at the age of 5 among children with a longer or shorter period of exclusive breast‐feeding (x2= 3.68, 9 df, NS). Exclusive breast‐feeding also did not affect the levels of salivary mutans streptococci (x2= 4.87, 9 df, NS). Children who were weaned late did not differ from those who were weaned early with respect to caries experience (x2= 6.12, 9 df, NS), level of salivary mutans streptococci (x2= 5.49, 9 df, NS) or presence of mutans streptococci (x2= 1.53, 4 df, NS). On the basis of our sample we concluded that breast feeding alone cannot be connected with an increased or lowered caries prevalence.
Root complex and root canal system: a correlation analysis using one‐rooted mandibular second molars
Authors: CARLSEN OLE
Published: October 2007

Abstract – The principal aim of this investigation was to verify an expected, probable correlation between certain variables, which are initially represented in the macrostructure of the root complex corresponding to the cemento‐dentin junction, and certain variables that subsequently manifest themselves in the root canal system. A material consisting of 76 one‐rooted, permanent mandibular second molars (M2 inf) was used. The specimens were cut at the mid‐root level and all observations were made on the coronal root segment using a stereomicroscope. Relevant variables of the root complex were observed. The total macromorphologic variation of the root complex could be subdivided and classified in well‐defined, distinguishable types. In accordance with the single root complex type an expected, logically deduced configuration of the root canal system was established. The relevant variables of the canal system were then recorded. Finally, the root complex morphology, as well as the expected and actually observed canal configuration, were compared type by type. In 76.3% of the teeth a good concordance could be shown between the expected and the actual canal configuration, whereas in 23.7% of the specimens there was a divergence. In 42.1% of the investigated teeth, 1 centrally localized main canal with varying cross section images, among them a C‐shaped image, was found. In 30.3%, 2 main canals were found, which were often localized mesially and distally. In 23.7%, 3 main canals were observed: 1 mesiofacial, 1 mesiolingual and 1 distal. In the remaining 3.9%, 1 non‐independent supernumerary canal was seen in a distolingual position.
Mineralization of and cementoblast attachment to original and reparative cementum
Authors: PHILIPSON STEFAN , LINDSKOG SVEN , FLOCK AKE
Published: October 2007

Abstract – Cementoblast attachment to original and reparative cementum as well as the mineralization pattern of the two tissues were studied ultrastructurally. Although differences were found in the mineralization pattern between the two types of cementum, cementoblasts attached to both with focal contacts, indicating a non‐motile synthesizing state of the cells. It was concluded that the differences in morphology between the two types of cementum are only reflections of the rate with which they are formed.
Marginal microhardness of corroded amalgams: a comparative in vitro study
Authors: PATSURAKOS AJIS , MOBERG LARS‐ERIK
Published: October 2007

Abstract – One conventional and two high‐Cu amalgams were tested for marginal microhardness after 2 months' corrosion in an 85 mM NaCl solution. Amalgams immersed in 200 mM phosphate buffer solution were used as controls. The microhardness tests were conducted on cross‐sections of the amalgams 50μm from the surface edges. The microstructure of the amalgams was studied in SEM and the amounts of Sn, Cu, Zn, Ag, and Hg dissolved in the solutions were analyzed with an atomic absorption spectrophotometer. For the amalgams immersed in the NaCl solution the depth of corrosion after 2 months was between 50 and 400μm. The specimens immersed in the phosphate solution showed no signs of subsurface corrosion. The marginal microhardness of all the amalgams was reduced after corrosion in the NaCl solution. The greatest microhardness in both the uncorroded and corroded states was shown in the two high‐Cu amalgams. The reduction in marginal microhardness after corrosion can probably be attributed mainly to degradation of the gamma‐2 phase for the conventional amalgam and to degradation of the η′ phase for the two high‐Cu amalgams.
Oral electrochemical action after soft drink rinsing and consumption of sweets
Authors: VASSILAKOS NIKOLAOS , NILNER KRISTER , BIRKHED DOWEN
Published: October 2007

Abstract – The aim of this study was to investigate the influence of pH changes in dental plaque and saliva on the magnitude of the galvanic current created when amalgam restorations make contact in the oral cavity. Ten persons with 46 contacts between amalgam fillings in all participated in the experiments. Potential, polarization, and pH measurements were performed before and after Coca‐Cola and orange juice rinsing and intake of sweets, which were used as test products. Distilled water was used as a control. The measurements were performed 2, 5, 10, 20, and 30 min after the rinsing or intake. There was no statistically significant difference in the current magnitude after any test product or between the time intervals after the different products. The results indicated that changes of the plaque and saliva pH for a short time after food and soft drink intake do not influence the magnitude of the galvanic current flowing between amalgam restorations in contact.
Enzymatic degradation of BISGMA/TEGDMA‐polymers causing decreased microhardness and greater wear in vitro
Authors: FREUND METTE , MUNKSGAARD ERIK CHRISTIAN
Published: October 2007

Abstract – The microhardness of the surfaces of BISGMA/TEGDMA‐polymers decreased after treatment with pork liver esterase for 48 h in concentrations 0.05 U/ml. This softening effect on BISGMA/TEGDMA‐polymer surfaces was also shown as an increased wear rate of the polymers in the presence of esterase measured by a laboratory abrasion method. In this method, polymer cylinders were vigorously shaken in an aqueous slurry containing abrasive particles. The shaking was performed for 3 s followed by a rest period of either 100 or 200 s. This was repeated for 24 h. A greater mean loss of weight of the cylinders was measured when esterase was present in the slurry and the loss of weight increased significantly from 6.7% to 23.8% (P<0.001) when the rest period was increased from 100 s to 200 s. The results indicate that enzymatic hydrolytic activity in the mouth will contribute to a breakdown of composite resin fillings.
Guinea pig maximization test with a polyether impression material
Authors: HENSTEN‐PETTERSEN ARNE , NILNER KRISTER , MÖLLER BENGT
Published: October 2007

Abstract – Adverse reactions to a polyether rubber impression material introduced in the midsixties have been reported in the literature. Most of the reports are inconclusive regarding the distinction between allergic and toxic responses. The aim of this study was to assess the allergenic potential of this material using a guinea pig maximization test. Ten guinea pigs in the experimental group were sensitized in two steps. First, an extract of the material was injected intradermally, and 7 days later, the material mixed in petrolatum was applied topically. After another 2 wk test solutions were applied, and the skin response was evaluated by visual inspection. Ten nonsensitized animals served as controls. From the challenge test it was evident that the catalyst as well as the freshly mixed material elicited positive skin reactions interpreted as being delayed hypersensitivity reactions. The findings indicate that the material contained substances which could be classified as strong to extreme sensitizers. Some of the adverse reactions seen in connection with the use of this material might well be related to delayed hypersensitivity reactions.
Microbial patterns in pooled subgingival plaque samples from young adults with advanced marginal periodontitis
Authors: FIEHN NILS‐ERIK , WESTERGAARD JYTTE
Published: October 2007

Abstract – Different bacterial profiles of subgingival plaque have been described for different clinical categories of marginal periodontitis. In the present investigation the subgingival microflora was studied in young adults with advanced marginal periodontitis. From 12 patients pooled subgingival plaque samples from 5 advanced stages of diseased sites were examined by direct differential phase‐contrast microscopy and by cultivation on enriched and selective media. The proportions of the following genera and species were calculated: black‐pigmented Bacteroides sp., B. gingivalis, Fusobacterium nucleatum, Veillonella sp., Actinobacillus actinomycelemcomitans, Capnocytophaga sp., Eikenella corrodens, Campylobacter sp., and Candida sp. Spirochete identification was carried out ultrastructurally. Calculated percent minimum similarity levels between the individuals revealed that each patient harbored its characteristic cultivable subgingival microflora different from the other individuals. The spirochetes seemed to constitute the subgingival bacterial group with the smallest variation as certain morphotypes were dominating in almost all individuals.
Dental anxiety in young adult Danes under alternative dental care programs
Authors: SCHWARZ ELI
Published: October 2007

Abstract – The purpose of the present report is to establish to what extent dental anxiety is expressed by young adults with a long history of regular dental care, to analyze whether expressions of dental anxiety vary during young adulthood in response to different dental care delivery programs, and to study which factors might account for existing expressions of dental anxiety. The study comprised 697 persons who participated in a longitudinal study on alternative dental care programs, running from the youngsters' 16th to their 19th yr. At the end, Corah Dental Anxiety Scale (DAS) was applied through self‐completed questionnaires. Overall DAS‐mean was 7.26; women expressed more anxiety than men (7.73; 6.78). Significant association between anxiety expressed at the end and at the start of the study indicated that dental anxiety was probably present at an early age. No association was found with utilization of dental services, A multiple regression analysis indicated early expressed dental anxiety and negative self assessment of dental health as important predictors for dental anxiety, while sex, negative assessment of gingival health, and dental program were of less importance, altogether explaining 22% of the DAS score variation. The risk group concept currently employed by the Public Child Dental Health Services might be extended to include expressions of dental anxiety.
Oral hygiene compliance and gingivitis expression in cigarette smokers
Authors: BERGSTRÖM JAN
Published: October 2007

Abstract – The compliance with an oral hygiene intervention program and its effect on oral cleanliness and gingivitis was studied in smokers and non‐smokers. The study group represented patients with regular dental attendance. It comprised 68 patients 21‐60 yr of age, including 28 habitual smokers. The program included toothbrushing with an electric toothbrush for 12 months. Oral cleanliness was evaluated according to a percentage plaque index and gingivitis according to the percentage of bleeding sites. The compliance with the oral hygiene program was very high among smokers and non‐smokers. Plaque index at baseline was very similar in smokers and non‐smokers and remained so during the course of the investigation. Following the introduction of the oral hygiene program, plaque index decreased in both groups, and there were no statistically significant differences between the two groups. In spite of the similarity in plaque index, gingival bleeding was significantly lower in smokers than non‐smokers. The results suggest that smokers and non‐smokers do not differ with respect to habitual oral hygiene or compliance with hygiene programs. In smokers, however, the clinical gingivitis expression in response to plaque is suppressed.
Mechanical properties of heat treated restorative resins for use in the inlay/onlay technique
Authors: ASMUSSEN ERIK , PEUTZFELDT ANNE
Published: October 2007

Abstract – Inlay/onlay materials based on composite resins have recently been introduced. It was the aim of the present study to investigate the effect of post‐curing temperature on selected mechanical properties. Four different composite resins were produced. The composite resins had identical filler content, but varied with respect to the content of the monomers BISGMA, TEGDMA, UEDMA, and HEMA. After Initial curing by light, the materials were post‐cured at 37, 100, 125, 150, 175, or 200°C for 1 h. We then measured diametral tensile strength, flexural strength, and modulus of elasticity. These properties were found to vary with the composition of the material. Composites containing UEDMA or UEDMA/HEMA were stronger and stiffer than BISGMA/TEGDMA formulations. The optimum post‐curing temperature was 150°C, but the increase in strength and stiffness was moderate, only about 9%.
Background factors in craniomandibular disorders: reported symptoms in adolescents with special reference to joint hypermobility and oral parafunctions
Authors: WESTLING LILIAN , MATTIASSON AGNETA
Published: October 2007

Abstract— Correlations between craniomandibular disorders (CMD) symptoms and an inherited factor (general joint hypermobility) were studied in 193 adolescents (96 girls and 97 boys). They answered a questionnaire concerning CMD symptoms, oral parafunctions, head and jaw trauma and symptoms from other joints. Joint mobility was assessed by determining the Beighton score (0‐9). Twenty‐eight percent of the girls and 21% of the boys could perform four or more of the maneuvres. Twenty‐two percent of the girls and 3% of the boys were extremely hypermobile (score ≥5). Eighty‐nine percent were aware of some oral parafunction and the prevalences of oral habits were about the same in the two groups. Girls reported significantly more dysfunction symptoms than boys. No indication was found that oral parafunctions generally produced CMD but a systemic factor (joint hypermobility) seemed to play an important role when the masticatory system was exposed to local forces as in oral parafunction. This may be one explanation for the predominance of females among CMD patients.
Effect of fluoride amalgams on artificial recurrent enamel and root caries
Authors: SKARTVEIT LIV , WEFEL JAMES S. , EKSTRAND JAN
Published: October 2007

Abstract— The present study examined the effect of F‐containing amalgams on recurrent caries in vitro. Four amalgams were tested: A ‐ Conventional amalgam; B ‐ Amalgam A with 1% SnF2; C ‐ Non‐gamma‐2 amalgam; D ‐ Amalgam C with 1% SnF2. Twenty fillings from each amalgam were placed at the cementoenamel junction in sound extracted human teeth. The teeth were covered with varnish except for a 2‐mm‐wide zone around the fillings and immersed in separate vials containing dialyzed 15% gelatin gel, pH 4.2, for 17 days. Longitudinal sections through the created enamel and root lesions were examined using polarized light microscopy with distilled water as imbibition medium. Lesion depth was measured adjacent to the fillings and at the midpoint of the lesions. In the amalgam D group, 14 enamel lesions and 15 root lesions showed no demineralization in the area closest to the fillings, and mean lesion depth was significantly smaller than adjacent to the F‐free amalgams in enamel as well asin root surfaces. In the root lesions, protection was most evident in amalgam D. At the midpoint of the lesions, depths were not statistically different between groups A‐D. This study suggests that fluoride amalgams have anticaries properties sufficient to inhibit recurrent caries.
Caries incidence after topical application of varnishes containing different concentrations of sodium fluoride: 3‐year results
Authors: HAUGEJORDEN OLA , NORD ALF
Published: October 2007

Abstract— Previous studies have shown that topical application of the fluoride varnish Duraphat reduces caries incidence. The aim of the present study was to compare the caries inhibiting effect of a new fluoride varnish (Carex) containing 1.8% fluoride (F) with that of Duraphat (2.26%F). Informed consent was obtained from the guardians of 495 children 10‐12 yr old in Voss Dental Health District (low F area). The children were randomly allocated to two groups. One group of subjects received 6‐monthly application of Duraphat (n=185), the other Carex (n=165). Ethical considerations precluded the use of a placebo varnish. All participants received dental examinations including one pair of posterior bitewing radiographs and necessary dental care annually. One trained examiner interpreted bitewing radiographs blindly. Total 3‐yr net DFS increment for 24 posterior approximal surfaces was 2.63 (SD = 3.81) in the Duraphat group and 2.12 (SD = 3.50) in the Carex group. DMFS increments based on 40 posterior occlusal and approximal surfaces were 5.21 (SD = 5.79) and 4.04 (SD = 4.92), respectively. Thus the results indicate a comparable efficacy for Carex and Duraphat at the caries activity level exhibited by these study participants.
Objective and subjective efficacy of saliva substitutes containing mucin and carboxymethylcellulose
Authors: OLSSON HÅKAN , AXÉLL TONY
Published: October 2007

Abstract— The lubrication properties of mucin and carboxymethylcellulose (CMC)‐containing saliva substitutes and water were evaluated in a double‐blind trial. After mouthrinsing with the substitutes, the patients answered a questionnaire (subjective effect) and the change of oral mucosal friction was measured with a probe (objective effect). Mucin and CMC‐containing saliva substitutes showed almost the same objective effects, with changed friction values of about 15 min, which was more than twice as long as for water. Both water and the two saliva substitutes relieved the symptoms of dry mouth to some extent but they did not have a sufficiently long‐lasting effect.