bluuebunny/crossref_metadata_2025 huggingface dataset:
Isoenzyme changes during rat facial development
Authors: GRANSTRÖM GÖSTA
Published: October 2007

Abstract –

A method is presented by which rat facial processes from different stages were obtained in pure fraction. The morphology, and protein and DNA contents in free dissected facial processes were determined. Facial processes of embryonic rats aged 9‐15 days were analyzed by isoelectric focusing for their isoenzymic distribution of four enzymes: lactate dehydrogcnase, creatine phosphokinase, fructose diphosphate aldolase and phosphoglycerate mutase. A dominance of LDH‐5, LDH‐4 and LDH‐3 isoenzymes was observed. As a comparison, LDH isoenzymes from mandibular and maxillary processes of rat embryos aged 9‐11 days only revealed LDH‐5 and to a smaller extent LDH‐4. The results support the presence of a prominent anaerobic metabolism in these tissues during early facial development. The change to LDH‐3 development correlates well with the formation of new blood vessels. From the ninth embryonic day, isoenzyme BB of creatine phosphokinase was present and during days 10‐15 MB and MM developed. Isoenzyme As4 of fructose diphosphate aldolase was present from the ninth embryonic day and isoenzymes A3C and A2C2 developed during days 10‐15. From the tenth embryonic day, isoenzyme BB of phosphoglycerate mutase was present and during days 10‐15 isoenzyme MB and MM developed. Isoenzyme development was first seen in mandibular processes, followed by maxillary, lateral nasal and medial nasal processes, and it preceded morphologic evidence of skeletal muscle formation.
Intraoral bacterial growth on tetracyclineimpregnated dentin
Authors: BJORVATN KJELL , SKAUG NILS
Published: October 2007

Abstract — Previous studies have shown that tetracyclines react with enamel and dentin in vitro to form slightly soluble compounds wish a pronounced and long‐lasting antimicrobial capacity. The purpose of the present project was to study the effect of doxycycline‐impregnation of dentin on the growth of oral microorganisms in vivo. Slabs of native human dentin were immersed in aqueous solutions of doxycycline HC1, 10 mg/ml, for 10 min, and were subsequently ligated to orthodontic brackets placed bucally on maxillary molars in seven individuals. Untreated native dentin specimens were similarly placed on contralateral teeth. Test and control specimens were removed from the oral cavity after 2 h, 24 h or 120 h, respectively. The individual specimens were then placed in 0.5‐ml saline and agitated mechanically for 30 s. The resulting bacterial suspensions were plated onto blood agar and various selective growth media. Based on CFUcounts obtained after incubation of the plates, doxycycline‐treated dentin specimens showed a significantly lower number of viable microorganisms after 2 h and 24 h in the oral cavity than did the control specimens. The bacterial growth was also less pronounced in the test specimens after 120 h. The effect of doxycycline was similar for all the cultivable bacteria. No significant difference in yeast growth was seen between test and control specimens.
Cigarette smoking in patients referred for periodontal treatment
Authors: PREBER HANS , BERGSTRÖM JAN
Published: October 2007

Abstract — 369 adult patients with moderate to severe periodontitis were compared with a survey sample from the population of Stockholm regarding smoking habits. The results showed that the frequency of daily cigarette smokers was significantly greater in the periodontitis sample. The odds ratio for a smoker to appear among periodontitis patients was more than doubled as compared to the population at large. In addition, the periodontal variables of PII, GI, probing depth and the patient's experience of gingival bleeding were recorded and compared between smoking and non‐smoking patients. PII was found to be similar in smokers and non‐smokers. Signs and symptoms of gingivitis as evidenced by the patients' experience of gingival bleeding and by GI were less pronounced in patients who smoke. Only 25% of smokers reported bleeding gingiva as compared to 51 % of non‐smokers. No differences were observed regarding probing depth except for lingual pockets of the maxilla where a significantly greater probing depth was observed in smokers. It was concluded that smokers may run an increased risk for periodontitis. Furthermore, gingival inflammatory symptoms seem to be suppressed in patients who smoke.
Aggregation of human salivary Ca‐proteinates in the presence of simple carbohydrates in vitro
Authors: SÖDERLING EVA , MÄKINEN KAUKO K.
Published: October 2007

Abstract — The effect of 8 polyols and 14 aldoses or ketoses on the spontaneous aggregation of Ca‐proteinates was followed spectrophotometrically in supernatants and filtrates of human mixed saliva. Each carbohydrate was added to the saliva samples at 37°C and the precipitated material was analyzed for protein, total carbohydrate and Ca. Based on their effect on aggregation, the carbohydrates could be divided into three groups: 1) those that showed no effect on aggregation: D‐xylose, D‐ribose and i‐erythritol, 2) those that inhibited aggregation strongly: xylitol, Dsorbitol and D‐mannitoi, and 3) those that inhibited aggregation moderately: glucose, fructose and sucrose. The inhibitory effect of the above polyols on the aggregation of Ca‐proteinates varied greatly among the saliva donors, and correlated positively with the turbidity of the saliva and its protein content more than with the Ca‐concentration or the pH of the saliva sample. It is suggested that inhibition of aggregation shown the most clearly for xylitol, sorbitol and mannitol manifests itself as a retardation of the final, irreversible aggregation of those glycoproteins that already exist in a precipitated form and which are responsible for the turbidity of saliva.
A new phosphate bonded investment
Authors: JÖRGENSEN KNUD DREYER , WATANABE AKIRA
Published: October 2007

Abstract — A new type of phosphate bonded investment has been studied. The setting expansion was found to be 0.03–0.05%, the thermal expansion was 1.54–1.85% depending upon the mixing liquid used: water or aqueous glycerol solutions, 5, 10, or 20%. Trial castings of alloys with a thermal expansion room to solidus temperature ranging from 1.60 to 1.91% showed either a very high accuracy or the possibility of improving the accuracy actually found by modifying the glycerol content of the mixing liquid used. To prevent cracking, heating of the investment mould in the temperature range 200–300°C must be slow, probably not faster than 2–3° per min.
Calcitonin gene related peptide: a sensory transmitter in dental pulps?
Authors: UDDMAN ROLF , GRUNDITZ TORSTEN , SUNDLER FRANK
Published: October 2007

Abstract — Nerve fibers displaying calcitonin gene related peptide (CGRP) immunoreactivity occurred in dental pulps of several mammals, including man. The CGRP fibers were more numerous in the apical parts than in the coronal parts and were distributed around small blood vessels as well as in the pulpal stroma without any obvious relation to blood vessels. The trigeminal, spinal and jugular‐nodose ganglia harbored a moderate supply of GGRP immunoreactive perikarya and nerve fibers. Immunocytochemic double staining revealed the coexistence of CGRP and SP in a population of perikarya in the sensory ganglia and suggested coexistence of the two peptides in perivascular nerve fibers in the cat dental pulp. The cervical sympathetic ganglia did not contain CGRP‐immnunoreactive perikarya. Cervical sympathectomy (studied in the guinea‐pig and rat) did not affect the frequency or distribution of pulpal CGRP fibers. The distribution of CGRP fibers within the dental pulp and the presence of CGRP perikarya in sensory ganglia known to supply the dental pulps indicate that the pulpal CGRP fibers are sensory in nature and that CGRP together with SP may participate in the regulation of local blood flow and the response to local inflammation.
Anxiety and dental fear in a group of parenteral drug addicts
Authors: SCHEUTZ FLEMMING
Published: October 2007

Abstract — The aim of the study was to evaluate whether general anxiety and dental anxiety were more common in a group of parenteral drug addicts. 41 drug addicts x̄=27.4 yr) attending a dental clinic in Aarhus in Denmark participated. A randomly sampled reference group comprising 350 individuals living in Aarhus and with similar age distribution was selected from the Central Person Register. Questionnaires with social and educational data and three self‐report rating scales, namely Corah's dental anxiety scale (CDAS) and Spielberger's State‐Trait anxiety inventory's two scales (STAI‐State and STAI‐Trait) were completed by the participants. Response rates were 95.6% and 89.3% for drug addicts and controls, respectively. Median CDAS, STAI‐State, and STAI‐Trait were 10, 46 and 44 in the addicts which was statistically significantly higher than in the general population. These differences were still present when the addicts were compared to a subsample from the reference group with a better matching of educational and social background factors. Spearman's correlation coefficient between CDAS and STAI‐State, CDAS and STAI‐Trait, and STAI‐State and STAI‐Trait were 0,57, 0.49 and 0.50, respectively, which were significant and moderately high correlations. Finally, anxiety levels were similar irrespective of caries experience.
Scanning electron microscope and electron microprobe study of reactions of stannous fluoride and stannous chloride with dental enamel
Authors: ELLINGSEN JAN EIRIK
Published: October 2007

Abstract — Stannous fluoride but not stannous chloride has shown a caries inhibiting effect in animal studies. The effect of aqueous solutions of stannous fluoride and stannous chloride on dental enamel surfaces was investigated by scanning electron microscope and analytical electron microprobe. Some large globules and a continuous layer of small globules were observed after stannous fluoride treatment. The large globules were soluble in both water and alkali, whereas the small ones were only soluble in alkali. Both fluoride and tin were found to be present on the enamel surfaces by the electron microprobe after stannous fluoride treatment. The fluoride could not be detected after immersion in distilled water whereas alkali treatment removed the tin. The large fluoride‐containing globules may consist of calcium fluoride as this substance is known to be slightly soluble in water and soluble in alkali. Stannous chloride treatment gave a layer of small tin‐containing globules with properties similar to the layer formed on enamel treated with stannous fluoride. It is therefore suggested that the tin‐containing layer is not associated with caries protection whereas calcium fluoride‐like deposition on the enamel probably is a factor in the caries inhibition caused by stannous fluoride.
Oral implantation of Streptococcus mutans in man with and without prior chlorhexidine mouthrinses
Authors: SVANBERG MONA , OLSSON JAN
Published: October 2007

Abstract — Oral implantation of streptomycin resistant S. mutans was enhanced when chlorhexidine mouthrinses were applied before implantation. The difference in recovery of implanted bacteria between implantations with and without prior chlorhexidine mouthrinses was significant 9 days (P<0.05), 15 days (P<0.05) and 28 days (P<0.01) after implantation. After 28 days implanted bacteria were no longer detected in any of the 20 test subjects when chlorhexidine was not used prior to implantation, but persisted in 11 subjects when chlorhexidine was used.
Malignancy grading of squamous cell carcinoma in the floor of the mouth related to clinical evaluation
Authors: ANNEROTH GÖRAN , BATSAKIS JOHN G. , LUNA MARIO
Published: October 2007

Abstract — A multifactorial grading system was used for histologic classification and grading of malignancy in 89 patients with squamous cell carcinoma in the floor of the mouth. All patients had been treated with surgery alone and only those patients were included in the study who at the initial diagnosis had no clinically suspected regional lymph node or distant metastatic involvement. There was a statistically significant correlation between the mean total malignancy scoring, on the one hand, and clinical staging, frequency of recurrences, and death from the first primary oral carcinoma, on the other.
Corrosion of dental alloys in vitro by differential oxygen concentration
Authors: RAVNHOLT GERT
Published: October 2007

Abstract — The corrosion of a conventional and a high Cu dental amalgam, a Cu‐Zn dental alloy, and pure silver (control) were studied in vitro under conditions of differential oxygenation, resembling a partially covered dental filling. The experimental method enabled the simultaneous recording of separate pH changes at anordic and cathodic areas and of the corrosion current generated; the corrosion products formed and the corroded alloys were examined by powder X‐ray diffraction, optical and scanning electron microscopy, and EDAX elemental analysis. Marled anodic pH drops and cathodic pH rises were seen which, with the total electric change integrated from the recordings, formed the basis for a qualitative evaluation (electrochemical reaction schemes) and a quantitative evaluation (amounts of metal corroded) of the progress of corrosion. The corrosion products found were SnG2, ZnSn(OH)6, and Cu2O of the amalgams, and Zn5(OH)8Cl2 of the Cu‐Zn alloy; twice as much tin corroded from the conventional as from the high Cu amalgam, and zinc corroded selectively from the Cu‐Zn alloy. These findings were substantiated by the microscopic and EDAX observations.
Absorption of fibronectin from human saliva by strains of oral streptococci
Authors: ERICSON DAN , TYNELIUS‐BRATTHALL GUNILLA
Published: October 2007

Abstract — Freshly collected human submandibular/sublingual saliva contained between 1.0 and 26.1 μ/ml of fibronectin as determined by ELISA. 109organisms of 12 oral streptococcal strains tested removed between 2.6 and 89.4% of the fibronectin present in 400 μl saliva. Fibronectin was retained in bacterial pellets after washings in buffer but could be eluted using 1 M NaCI
Posteruptive tooth age and severity of dental fluorosis in Kenya
Authors: BAELUM VIBEKE , MANJI FIROZE , FEJERSKOV OLE
Published: October 2007

Abstract – The purpose of the present study was to assess whether the degree of severity of enamel changes in a population exhibiting rather severe dental fluorosis may be related to posteruptive tooth age and to describe the clinical manifestations of the enamel destructions. All permanent teeth in 102 children aged 10–15 yr who were born and reared in a 2 ppm fluoride area of Kenya were examined for dental fluorosis using the TF‐Index. Clinically, at time of eruption all teeth appeared chalky white, but already prior to coming into occlusion discrete pits had formed. A variety of more extensive damages to the surface enamel was found in teeth already in occlusion. In particular, the maxillary incisors exhibited extensive artificial attrition for cosmetic reasons, which make these teeth unreliable for accurate scoring of severity in the present population. An analysis of the proportion of teeth exhibiting TF1‐scores 4+, 5+ and 6+ showed that children aged 13–15 yr had a significantly greater proportion of teeth with TFI‐scores >6 compared to children aged 10–12 yr (Wilcoxou, P<0.0001). This finding is unlikely to be a result of different fluoride exposures in the two age groups and indicates that even several years after eruption there is a trend towards an increasing severity of enamel surface destructions in children exhibiting pronounced degrees of subsurface enamel hypomineralization at time of eruption.
Porosity in posterior composite resins
Authors: VAN DIJKEN JAN W. V. , RUYTER I. EYSTEIN , HOLLAND ROY I.
Published: October 2007

Abstract – The percent pore area and the mean pore size were measured in specimens made of nine brands of composite resin restorative materials. The overall percent porosity ranged from 0.01 to 4.5%. The specimens for the study were prepared in two ways; by condensation or by pressure. Most of the materials, including all those chemically activated, showed more porosity in the condensed than in the pressure specimens. Reversed results emerged for two of the materials, and for another two, the specimens were similar in this respect. The mean pore sizes were smaller in the condensed than in the pressure specimens. Neither mean pore size nor total amount of porosities could be correlated to the curing method of the materials.
Effect of a sport drink mixture with and without addition of fluoride and magnesium on plaque formation, dental caries and general health of rats
Authors: SORVARI RITA , KOSKINEN‐KAINULAINEN MAARIT , SORVARI TAPANI , LUOMA HEIKKI
Published: October 2007

Abstract – A sport drink mixture (pH 3.2) containing 6% sucrose was given to Osborne‐Mendel rats for 42 days. In some experimental groups the drink was supplemented with 15 ppm F, 38.5 ppm Mg or both F and Mg. The rats were fed a slightly cariogenic powdered diet containing 15% sucrose. Sport drink mixture increased significantly the accumulation of plaque but, compared with a group that drank distilled water, did not affect caries. Addition of fluoride to the sport drink mixture, alone or with magnesium, significantly reduced caries and tended to decrease plaque; addition of magnesium had no clear effect on plaque or caries. In spite of the fact that the rats had a sport drink mixture as the only drink for 6 wk, there were no untoward effects on growth, in histological studies of the inner organs, or in Ca, Mg, Na and K contents of kidney, heart and aorta.
Scanning electron microscopic study of giant tubule content in bovine dentin
Authors: DYNGELAND TROND , FOSSE GISLE
Published: October 2007

Abstract — Incisal segments of unerupted permanent incisors from l/Z‐l l/2‐yr‐old calves were fractnred along an axiomesiodistal plane exposing the organic components within the giant tubule lumina situated in this plane. Along the lining wall of the pulpal vasclurized giant tub & portion, large flattened cells and a few odontoblasts were situated in shallow depressions. Just incisal to the vascular loop numerous cells were seen, both along the giant tubule wall and enclosed within a loosely textured collagsnous matrix. Further incisally, the number and size of the cells decreased, and they were embedded in a compact nnmineraPized collagenous matrix that completely filled out the giant tubule lumina. This matrix consisted of fibrils regularly arranged in separate bundles whose orientation was mainly longitudinal. The initial origins of the giant tubes were filled with coarse Fmhrils being about three times thicker than those of the luminal matrix and those of the circumpulpal dentin proper.
Biophysical and microbiologic studies of “heavy” and “light” plaque formers
Authors: SIMONSSON THOMAS , EDWARDSSON STIG , GLANTZ PER‐OLOF
Published: October 2007

Abstract — In order to trace factors possibly influencing initial bacterial colonizatirrn of tooth surfaces, a multiple linear regression analysis was performed on the present results as well as on those from certain clinical and biochemical studies previously performed in the same subjects. No statistically significant difTerences were observed between the two groups of plaque farmers for the individual parameters. The multiple regression analysis showed, however, that the calculated work of adhesion for two polar and one non polar test liquid, the rate of unstimulated salivary secretion, morphologic differences in the dento‐gingival areas of maxillas premolars and saliva‐induced aggregation of S. mitior were crucial for about 90% of the variation in the number of CFU colonizing tooth surfaces after both 2 and 6 h. Both electrostatic and van der Wall's forces, as well as salivary flow conditions could thus have influenced the initial attachment of bacteria to the test surfaces. It is concluded that saliva including its suspended microorganisms could Be looked upon as being a colloidal biological system, and if so, the initial bacteria1 colonization of tooth surfaces should follow known, general biophysicai laws.
Rate of plaque formation – some clinical and biochemical characteristics of “heavy” and “light” plaque formers
Authors: SIMONSSON THOMAS , RÖNSTRÖM ANDERS , RUNDEGREN JAN , BIRKHEB DOWEN
Published: October 2007

Abstract –The purpose of the present study was to give a clinical arid biochemical characterization of two groups of individuals with different rates of plaque formation. From 133 individuals, 9 “heavy” and 10 “light” plaque formers were selected. The mean plaque index after 3 days of plaque accumulation, on buccal surfaces of premolars and first molars, was 2.6 for the “heavy” and 0.6 for the “light” plaque formers. The following variables, were determined: periodontal status, DFS, dietary habits, salivary secretion rate and buffer effect, S. mutans and lactobacillus counts in saliva, salivary content of IgA, lactoferrin, lactoperoxidase and lysozyme, saliva‐induced aggregation of certain oral streptococci, gel electrophoresis of saliva, amino acid composition of saliva and the acquired pellicle and retention depth of the dentogingival area. Comparing the two groups of plaque formers, statistically significant differences were found for the following three variables: parotid saliva‐induced aggregation of a strain of S. sanguis, content of glutamic acid in the acquired pellicle and retention depth of the dentogingival area for maxillary premolars. Large variations for all studied variables were found, both within and between the groups. Several factors may be involved in plaque formation and none of the studied variables alone could explain the large difference in the amount of plaque formed after 3 days between the “heavy” and “light” plaque formers.
In vitro attachment of oral microorganisms to solid surfaces: Evaluation of a controlled flow method
Authors: CHRISTERSSON CECILIA E. , FQRNALIK MARK S. , BAIER ROBERT E. , GLANTZ PER‐OLOF J.
Published: October 2007

Abstract – A flow cell method was modified to provide shear‐controlled experimental conditions for monitoring initial attachment and detachment of oral microorganisms, to solid surfaces. Whole unstimulated human saliva was collected and circulated at a flow rate of 1 ml/min, through a cell composed of two parallel test plates. Infrared‐transparent plates of medium surface energy served as test substrata in these initial calibration experiments. The plates presented a similar distribution of polar forces and dispersion forces at the surface as that of human tooth enamel and some restorative dental materials. Internal reflection infrared spectroscopy verified the presence of deposited organic material. After saliva had been circulated through the flow cells for 15 min at 37 ° C, sterilized distilled water was introduced at the same flow rate and time of exposure to remove unattached microorganisms. Morphologic characterizations and counts of adherent Gram‐stainable microorganisms were performed using incident light microscopy. Three different surface zones corresponding to the inlet area, the middle area and the outlet area of the flow cell were analyzed, and compared with enumerations of microorganisms in the whole saliva samples. Numbers of attached microorganisms in the three zones followed predictions from the laminar flow conditions, with a positive correlation shown between total numbers of microorganisms in saliva and total numbers of microorganisms attached. Cocci and rods were the only morphotypes observed on the plates, and no significant difference could be detected between the percentage of cocci and rods attached in the three different zones. The results showed high deposition efficiency from the zone immediately adjacent to the test surfaces. No apparent morphological selectivity was induced. This flow cell method has numerous advantages for monitoring the influence on cellular adhesion of varying liquid phase and solid surface combinations, under dynamically controlled experimental conditions. It is particularly useful for small sample volumes and short exposure times.
Effect of Gluma in acid‐etched dentin cavities
Authors: HANSEN ERIK KEITH
Published: October 2007

Abstract – The marginal adaptation of a restorative resin in combination with a dentin bonding agent was investigated in dentin cavities treated either with a strong solution of phosphoric acid or with an 0.5 M EDTA solution neutralized to pH 7.4 with NaOH. It was found that both the maximum marginal contraction gap and the extent of the gap were significantly increased in acid‐etched cavities when compared to cavities cleaned with the EDTA solution.
Pattern of periodontal breakdown in adult Tanzanians
Authors: BAELUM VIBEKE
Published: October 2007

Abstract – A total of 170 adult Tanzanians aged 30‐ 691 yr were examined for loss of attachment, gingival recession, plaque, calculus and gingival bleeding on all surfaces, of all teeth. The severity of loss of attachment varied considerably between tooth types. Irrespective of age, mandibular incisors and first and second molars were the teeth most affected by loss of attachment. In all age groups heavy plaque deposits and gingival bleeding occurred more frequently in posterior than in anterior teeth, Dental calculus was most frequently observed in the maxillary posterior and mandibular anterior teeth. The distribution of calculus within the dentition showed a close resemblance with the patterns of loss of attachment and gingival recession. The variation of the severity of periodontal breakdown within individuals indicates that the use of mean values to describe periodontal breakdown may give the impression of a greater uniformity than really exists.
Synthesis of sulfated glycosaminoglycans by human gingival fibroblasts from phenytoin‐induced gingival overgrowth in vitro
Authors: DAHLLÖF GÖRAN , HJERPE ANDERS
Published: October 2007

Abstract – The in vitro synthesis of sulfated glycosaminoglycans (GAGs) was studied in gingival fibroblasts from two patients exhibiting phenytoin(PHT)‐induced gingival overgrowth, i.e. pseudopockets, which required surgical excision, from one patient on PHT medication not exhibiting pseudopockets and from two normal controls. The results showed that the newly synthesized GAGs were distributed to the culture medium, to a pericellular pool and to the cell fraction. Gingival fibroblasts from the PHT‐induced gingival overgrowth showed a significantly increased incorporation of 35SO42‐ into GAGs compared to the other strains, and this, increase was mainly confined to the dermatan sulfate fraction. These results are in accordance with our previous biochemical studies where increased amounts of GAGs were found in gingival biopsies from the PHT‐induced lesion.
Malignant transformation in oral leukoplakia
Authors: LIND PETTER O.
Published: October 2007

Abstract – A retrospective study on the incidence of malignant transformation in oral leukoplakia was performed covering the period from 1970 to 1980. Carcinoma developed in 11 of the 157 patients, and this 7% incidence increased to 8.9% when the same patients were followed prospectively for 6 more years. Dysplasia was fotind in biopsies from 51 patients (31.8%), and was significantly more frequent in women than men (P<0.05). Dysplasia grade and cancer development were related to updated clinical and etiological parameters.
Histologic characteristics of clinically healthy gingiva in adolescents
Authors: LAURELL LARS , RYLANDER HARALD , SUNDIN YVONNE
Published: October 2007

Abstract – Gingival biopsies from healthy buccal gingival units in 10 young individuals (12–14 yr) were analyzed morphometrically. The connective tissue was generally characterized by a dense collagenous network, apart from a well defined zone subjacent to the smooth and noninfiltrated juncdonal epithelium. This zone, which constituted on average 10%, of the connective tissue volume, was less dense than the remaining part of the connective tissue and devoid of well defined collagen fiber bundles. This zone could also harbor clusters of infiammatory cells, mainly mononuclear cells, surrounded by non‐infiltrated collagen‐poor connective tissue, in the noninfiltrated collagen‐dense mid‐portion of the gingival connective tissue small areas of infiltrates could be found, the composition of which resembled that of the infiltrated areas subjacent to the junctional epithehum.
Effects of irradiation with dental light curing units on Langerhzuis cells in human stratified epithelium in heterotransplanted skin
Authors: BONDING NINA , GRAEM NIELS , RYGAARD JÖRGEN , DABELSTEEN ERIK
Published: October 2007

Abstract – Grafts of human skin on nude mice were subjected to a single dose of either 21/2 min or 4 min of radiation from two different commercial dental light curing units with emission mainly in the visible light spectrum but also with a small fraction of UV‐A light. Seventy‐two hours after exposure the tissue was examined for presence of Langerhans cells using monoclonal antibody OKT6 double layer immunofluorescence staining. Epithelial hyperplasia and reduced reactivities for OKT6 were seen after 21/2 min exposure. After 4 min of exposure OKT6 positive ceils were completely absent from the epithelium. The results indicate that emission from dental light curing units can affect Langerhans cells in human epithelium and could thus modify the local immunologic response.
Erosive effect of a sport drink mixture with and without addition of fluoride and magnesium on the molar teeth of rats
Authors: SORVARI RITA , KIVIRANTA ILKKA , LUOMA HEIKKI
Published: October 2007

Abstract – A sport drink mixture (pH 3.2), either as such or supplemented with 15 ppm F or 38.5 ppm Mg or both, was given to Osborne‐Mendel rats as the only liquid for 42 days. The erosion was scored on the lingual surfaces of the first mandibular molar teeth. Sport drink caused marked erosion, but in the groups where fluoride, alone or with magnesium, was added to the drink, the erosion damages were less severe. Magnesium alone had no clear effect on erosion. Dental plaque, induced by a powdered diet containing 15% sucrose, seemed to modify the erosion process by covering a part of the enamel and thus protecting these areas from the direct effect of acidic drink.
Oral function in subjects with overdentures supported by osseointegrated implants
Authors: HARALDSON TORGNY , JEMT TORSTEN , STÅLBLAD PER‐ÅKE , LEKHOLM ULF
Published: October 2007

Abstract – Nine subjects treated with overdentures on osseointegrated implants in the mandible were functionally evaluated before and after treatment. The last recordings were performed 1 yr after treatment. The evaluation comprised a subjective and a clinical examination. Measurements of bite force and of chewing efficiency were also performed. The bite force was measured during gentle biting, biting as when chewing and biting with maximal effort. Almonds, were used as test food. All subjects improved subjectively as well as clinically after treatment. The bite force during gentle biting increased on average from 17.3 N before treatment to 24.0 N 1 yr after treatment. A corresponding improvement of biting as when chewing was also found, from on average 24.0 N before to 38.7 N after treatment. The maximal bite force increased from on average 74.6 N at the baseline examination to 131.5 N at the 1‐yr follow‐up. The chewing efficiency improved from Ci=4 (Median value) before treatment to Ci=2.8 (Median value) after treatment. It is concluded that treatment with an overdenture supported by osseointegrated implants in the mandible improves oral function compared to the situation before treatment.
A 10‐year follow‐up study of the masticatory system after treatment with osseointegrated implant bridges
Authors: HARALDSON TORGNY , ZARB GEORGE
Published: October 2007

Abstract – Twenty‐one patients with osseointegrated implant bridges (OIB), with an average age of 65 yr, were functionally examined at a 10‐yr follow‐up. Altogether 27 OIBs, supported by 138 fixtures, were examined. The examination comprised an anamnestic and clinical examination and registration of bite force. 90% of the patients were very satisfied with the outcome of the treatment. According to the anamnestic dysfunction index (Ai), 80% of the patients were symptom free in their masticatory system. The occlusal state was found to be good. Seventy‐five percent of the patients were found to have only mild dysfunction of their masticatory system or to be symptomless according to the clinical dysfunction index (Di). The bite force ranged from 3 to 118 N at gentle biting, from 25 to 250 N at “biting as when chewing” and from 77.5 to 495.5 N at maximal bite force. On average the bite force had improved significantly at all biteforce levels tested compared to an examination 10 yr earlier. It is concluded that oral function in patients with OIBs is very favorable.
Impression materials: effect of hydrophilicity and viscosity on ability to displace water from dentin surfaces
Authors: PEUTZFELDT ANNE , ASMUSSEN ERIK
Published: October 2007

Abstract – The water‐displacing ability of hydrophilic and hydrophobic impression materials was determined and related to the hydrophilicity and viscosity of the materials. The waterdisplacing ability of the materials was determined on a network of grooves in a dentin surface covered by a drop of water. After setting of the material, the number of crossings reproduced in the impression was calculated in percent of the total number of crossings. The hydrophilicity was assessed by measuring the contact angle between water and impression material. To determine viscosity, a rotoviscosimeter was used. Impression materials with contact angles less than 70° showed a significant negative correlation between water‐displacing ability and contact angle, i.e. the reproducing ability decreased with decreasing hydrophilicity of the materials. Impression materials with contact angles above 70° showed a significant positive correlation between water‐displacing ability and viscosity, i.e. the water‐displacing ability improved with increasing viscosity.
Organic structures of developmental origin in human surface enamel
Authors: NYVAD BENTE , FEJERSKOV OLE , JOSEPHSEN KAJ
Published: October 2007

Abstract – The aim of this study was to examine the distribution of organic material in mature enamel surfaces immediately prior to eruption. Thirty‐six samples of buccal or lingual enamel from unerupted third molars were prepared for transmission electron microscopy by a method involving demineralization of the enamel after embedding in Epon. The results showed that at time of eruption human surface enamel is a highly porous structure containing large amounts of developmental protein which appear as a variety of triangular, funnel‐shaped, or invaginated configurations extending into the enamel. The implications of this finding may be of importance to the understanding of early caries lesion formation in the enamel since organic structures may modify the diffusion of ions in and out of the tissue.
Cervical abrasion in relation to toothbrushing and periodontal health
Authors: BERGSTRÖM JAN , ELIASSON SÖREN
Published: October 2007

Abstract – Cervical abrasion and some factors related to oral hygiene habits and periodontal health were investigated in 250 subjects aged 21–60 yr. The subjects were considered dentally aware since they had visited their dentist on a regular basis over the past several years. A high occurrence rate of cervical abrasion was noted with 85% of subjects exhibiting at least one superficial lesion. Manifest or deep lesions, although less common, were present in 22% of subjects. Both prevalence and severity increased with age. The severity expressed as the mean number of lesions was 7.3 for the total sample. It increased significantly with calculus index, frequency of periodontal pockets, and reduction of the alveolar bone height. No significant associations were observed between abrasion and oral hygiene factors. It is concluded that cervical abrasion, although most likely related to toothbrushing, may not be synonymous with periodontal health. Ineffective toothbrushing may not only fail to prevent disease but may also cause cervical abrasion.
Effect of pyrophosphate on protein adsorption to hydroxyapatite in vitro and on pellicle formation in vivo
Authors: RYKKE MORTEN , RÖLLA GUNNAR , SÖNJU TORLEIF
Published: October 2007

Abstract – This study showed that pyrophosphate (PP) desorbed an acidic protein (albumin) from hydroxyapatite (HA) more effectively than phosphate and that HA pretreated with PP took up markedly less protein than untreated HA. The protein which adsorbed to PP‐treated HA was more loosely bound than that adsorbed to untreated HA. In vivo experiments showed that pellicle formed more slowly on PP‐treated etched enamel than on untreated controls. The possible clinical implications of these findings are discussed.
Effect of disinfecting solutions on accuracy of alginate and elastomeric impressions
Authors: PEUTZFELDT ANNE , ASMUSSEN ERIK
Published: October 2007

Abstract— The effect of immersion in six disinfecting solutions on the accuracy of 10 impression materials was investigated. Impressions were taken of a truncated steel cone. 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 iron), and after 24 h poured with gypsum. A steel ring fitting the steel cone was placed on the resulting dies, and the discrepancy between the top surface of the ring and the die was measured. From these measurements the deviation between the base diameter of the die and of the impression was calculated to express the inaccuracy. All impressions except some in Blueprint exhibited a net shrinkage, giving rise to too large die stones and incomplete seating of the steel ring. Blueprint impressions, however, occasionally swelled and resulted in too small die stones and “overseating” of the steel ring. The disinfecting solutions had no significant impact on two impression materials. For the remaining eight materials the accuracy was decreased, increased, or unaffected by the immersion. Generally, the accuracy of the alginates investigated were more affected by the disinfecting solutions than were the elastomeric impression materials. The accuracy of the three alginates was drastically impaired by immersion in 70% ethanol, whereas the remaining five disinfecting solutions had a smaller, though sometimes statistically significant, effect on the accuracy. For the elastomeric materials only a few specific combinations of impression material and disinfecting solution reduced the accuracy. Since the control values of accuracy varied, it was concluded that the choice of elastomeric impression material is more critical than the choice of disinfecting agent. As for the alginates, brand as well as type of disinfecting solution have to be considered to obtain an acceptable accuracy of disinfected alginate impressions.
Dental root translucency as an indicator of age
Authors: SOLHEIM TORE
Published: October 2007

Abstract –The apical translucent zone was studied in 1000 human teeth. For each type of tooth, excluding molars, the size of the apical translucency was estimated according to the scoring methods of Gustafson(I), Dalitz(2) & Johanson(3). The lengths of the translucent zones were measured on moist and then on dry teeth, both unsectioned and sectioned, while the areas were measured on dry sectioned teeth only. Statistical analyses using the SPSS package in a Cyber computer indicated a symmetric distribution of the translucent zone in left and right teeth. The extent of the translucency showed little variation from one type of tooth to another. The length of the translucent zone measured on unsectioned teeth demonstrated in most types the closest relation to age. Multiple regression analyses, including more than one method of measuring the size of the translucent zone, resulted in formulas showing a high correlation with age (from 0.68 to 0.86). Slightly larger translucent areas were found in teeth from males, in darker teeth and in teeth with increased thickness of the cementum. The increase in the translucent zone with advancing age was found to be almost linear and was not affected by periodontal destruction.
Chemical and structural challenges in remineralization of dental enamel lesions
Authors: LARSEN MOGENS JOOST , FEJERKOV OLE
Published: October 2007

Abstract – The aim of the present paper was to identify some chemical and structural factors which may prevent a full remineralization of caries lesions and to study whether it is possible to overcome such obstacles. Samples of powdered enamel apatite were equilibrated with solutions metastably supersaturated with respect to enamel hydroxyapatite and fluorapatite. After 10 min and 60 min of equilibration at 20°C the suspensions were centrifuged and the calcium and phosphate concentrations and the pH were determined in the supernatant. In parallel studies, 50–75‐μm‐thick sections of 27 fluorotic teeth of a severity of 5–7 according to Thylstrup and Fejerskov's classification were examined by microradiography and in polarized light using distilled water, and Thoulett's media or seen dry in air. Five obstacles inhibiting remineralization were identified: 1) Although remineralizing solutions or saliva are supersaturated with respect to enamel apatite the total amount of calcium and phosphate dissolved in it is small, so that after precipitation of the dissolved mineral only 1/20 000‐1/30 000 of the volume of the mineralizing solution is occupied by mineral. 2) The concentration gradients from the mineralizing solution into the enamel is small, which indicates a slow diffusion into and out of the lesion. 3) The uptake of calcium and phosphate by the enamel apatite crystals is so rapid that the aqueous phase within the pores can be presumed to be only marginally supersaturated in the deeper parts of the lesion. 4) The surface layer of the enamel lesions was found to be a serious obstacle to remineralization so that a subsurface area remains hypomineralized after exposure to salivary remineralization even for a lifetime. 5) Nucleation of new apatite crystals to substitute lost crystals is an unsolved problem.
Caries preventive effect of fluoride varnish applications performed two or four times a year
Authors: SEPPÄ LIISA , TOLONEN TYTTI
Published: October 2007

Abstract – The efficacy of Duraphat varnish applications performed two or four times a year was compared in a 2‐yr clinical trial. 254 children aged 9‐13 yr and having higher than average DMFS values participated in the study. The children were randomly divided into two treatment groups. Clinical and radiographical examinations were performed at baseline and after 2 yr by one dentist. For the group receiving applications every 3 months, the 2‐yr DMFS increment was 2.90 (SD 4.45) and for the group receiving applications every 6 months, 2.92 (4.47). There were no significant differences in DMFS increments between the groups for any type of tooth surfaces. Neither was there any difference between the groups when the children were divided into two subgroups on the basis of baseline DMFS values. The increments for the children with high (10) baseline DMFS values were 4.25 (4.81) and 4.30 (5.53) in the groups receiving applications four times and twice a year, respectively. The results suggest that fluoride varnish applications performed more frequently than twice a year may not provide additional caries protection in a population with relatively low caries activity.
Occurrence of malocclusion in attritive environment: a study of a skull sample from southwest Finland
Authors: VARRELA JUHA
Published: October 2007

Abstract – Occlusal variation and occurrence of malocclusion were examined in a Finnish skull sample derived from the 15th and 16th centuries. The material consisted of 207 adult individuals; 141 maxillas and 159 mandibles, including 93 pairs, were in observable condition. In the skull sample, only dental anomalies were observed; no skeletal malocclusions were found. The frequency of an Angle Class I lateral relationship was 97.7%. The mean values for overjet and overbite were 1.6 and 1.4 mm, respectively. A comparison with present‐day Finns revealed that the skull sample showed less variation in all occlusal variables studied. An Angle Class II type occlusion, deep bite, crowding, spacing, and lateral crossbite occurred with significantly lower frequencies in the skull sample than in the present‐day Finns. Advanced dental wear in the skull sample shows that a hard and attritive diet was eaten at that time. It is suggested that a dietary transition from hard to soft food is the most probable cause of the increased occlusal variation and high frequency of malocclusion in present‐day Finns.
Radix entomolaris: identification and morphology
Authors: CARLSEN OLE , ALEXANDERSEN VERNER
Published: October 2007

Abstract – The Royal Dental College, Copenhagen, houses an extensive collection of human teeth, extracted in Denmark. At present, the collection includes 398 permanent mandibular molars with a root complex containing a lingually‐located supernumerary root. This macrostructure is called radix entomolaris (RE). By analyzing the large number of available specimens it was possible to establish uniform and precise criteria for the identification of RE on M1 inf, M2 inf, and M3 inf. The analyses included separate as well as non‐separate RE. The representation of the RE variants according to tooth types was mapped. Furthermore, the following relevant clinical variables with respect to RE were registered: degree of separation, divergence, apical bend, apical gracility, and fusion. Because of the nature of the material, the investigation was mostly qualitative and non‐metric. The results should be of interest to clinical dentists, dental morphologists, and dental anthropologists.
Root surface caries and associated factors
Authors: FURE SOLVEIG , ZICKERT INGEGERD
Published: October 2007

Abstract – The prevalence of root surfaces caries in 208 randomly selected 55, 65, and 75‐yr‐old Swedes was related to the frequency of coronal caries, the number of remaining teeth and to bacteriologic, salivary, and dietary variables. At least one decayed or filled root surface was found in 89% of the individuals and all of those had also experienced coronal caries. The frequency of root surface caries was positively correlated to the frequency of coronal decay and negatively correlated to the number of remaining teeth and exposed root surfaces. The study shows that the same factors which are associated with enamel caries seem to be of importance in determining the development of root surface caries. The variation in the frequency of root surface caries was best explained by the salivary levels of mutans streptococci and lactobacilli, the percentage of surfaces harboring plaque and the frequency of carbohydrate intake. Other contributory factors were the saliva secretion rate and the buffer capacity.