bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Clinical, Radiographic, and Histological Evaluation of Permucosal Dental Implants of Dense Hydroxylapatite in Dogs
Authors: De Lange G.L. , De Putter C. , De Groot K. , Burger E.H. 
Published: November 2010

A clinical, histological, and radiographic examination was performed on 77 permucosal dental implants, made of dense sintered hydroxylapatite: 34 solid cylinders and 43 hollow cylinders. The hollow cylinders were pre-compressed between two titanium caps. The implants were placed in partly edentulous mandibles of dogs, and were physiologically loaded. Healing was clinically and radiographically evaluated during a six-month to five-year period. At various times, implants with their surrounding tissues were removed and prepared for light and electron microscopy. All implants showed a good initial fit and were maintained in place without undercut or mechanical stabilization. After 18 months, 76% of the solid cylinders had fractured at the implant/bone junction due to fatigue. However, the submerged portions of the solid cylinders were preserved without clinical problems, and became entirely embedded in bone. The pre-stressed implants did not fracture, and 91% were functioning 24 months after placement. The average scores of pocket depths and gingival bleeding showed no significant differences between implants and surrounding natural teeth. Bone deposition occurred on the entire surface of the implant below the crest of the alveolar bone, and intimate bone contact was confirmed by electron microscopy. It was also observed that a layer of bone tissue was deposited on the implant surface in the permucosal area just above the alveolar bone level. Embedding of gingival fibers in this layer resulted in gingival attachment to the implant, comparable with that of natural teeth.
In vivo Effects of Zinc and Chlorhexidine on Dental Plaque Ureolysis and Glycolysis
Authors: Giertsen E. , Scheie A.Aa. , Rolla G. 
Published: November 2010

We assessed the in vivo effects of zinc and chlorhexidine (CH) on plaque ureolysis and glycolysis in five volunteers. We monitored plaque pH by a surface glass electrode on two teeth in each subject, after topical application of either 5% wt/vol urea or 5% wtlvol glucose solutions. The recordings were repeated 15 and 75 min after a single mouthrinse, with either 20 mmol/L zinc acetate or 0.33 mmol/L CH diacetate. Ureolytic activity decreased significantly (p<0.03) up to 75 min after a single mouthrinse with the zinc-containing test solution. CH had no effect on plaque ureolytic activity. Acid production by dental plaque decreased significantly (p < 0. 01) up to 75 min after a single mouthrinse with either the zinc- or the CH-containing test solution.
The Effect of pH on the Sensitivity of Species of Lactobacillus to Chlorhexidine and the Antibiotics Minocycline and Spiramycin
Authors: Cleghorn B. , Bowden G.H. 
Published: November 2010

The purpose of this study was to determine the sensitivity of a range of Lactobacillus species to chlorhexidine, Minocycline, and Spiramycin, at a range of pH from 5.0 to 7.4. Strains of Streptococcus were also tested for their sensitivity to chlorhexidine, as a comparison between the genera. There were both inter- and intra-species variations in the sensitivity of these strains to chlorhexidine. The strains tested were sensitive at pH 6. 7 to the following levels of chlorhexidine (μg/mL) : L. casei (6 strains), 10-60; L. plantarum (4 strains), 40; L. fermentum (13 strains), 2-20; L. brevis (1 strain), 10; and L. acidophilus (3 strains), 10-60. The Streptococcus species were sensitive to 1-4 μ/mL (13 strains); 4-10 μg/mL (3 strains); and 10-20 μg/mL (2 strains). One strain was able to survive 20 μg/mL. Chlorhexidine was found to be less effective at lower pH levels. The following examples show sensitivity (μg/mL) at pH 6.5 followed by sensitivity at pH 5.0 : L. casei (ATCC 15008), 40,60 ; L. plantarum (CH 374), 40,100 ; L. fermentum (CH 324) 10,40 ; L. acidophilus (ATCC 4356), 10,40 ; and S. mutans (BM 52), 2,2. All of the strains of Lactobacillus tested with Spiramycin were resistant at pH 5.0. Minocycline was less affected by changes in pH, but at pH 7.4 Lactobacillus strains were more resistant to Minocycline as compared with Spiramycin. Both of these antibiotics are bacteriostatic, and therefore may have a more limited effect than a bactericidal agent such as chlorhexidine. The Lactobacillus strains tested required higher concentrations of chlorhexidine than did the strains of Streptococcus for a killing effect in vitro.
Surface Tension and Contact Angle on Enamel of Surfactant Solutions for Caries Diagnosis with Dyes
Authors: Van de Rijke J.W. , Busscher H.J. , Ten Bosch J.J. , Perdok J.F. 
Published: November 2010

We measured the surface tension of solutions of five surfactants in water, ethanol, and a 50% water/ethanol mixture at 25°C, as well as the contact angle of these solutions on ground and polished bovine enamel in vitro and on intact pellicle-covered human enamel in vivo. All surfactants lowered the surface tension of water. In ethanol, no reduction of the surface tension was achieved by any of the five surfactants. In the water/ethanol mixture, only Fluorad® lowered the surface tension from 29.2 to 19.7 mJ.m-2 at 25°C. On bovine dental enamel, all surfactant solutions showed a significantly lower contact angle than did distilled water. On pellicle-covered human enamel, Rewoteric® in distilled water showed no significantly lower contact angle than did pure distilled water, but all other solutions did. Both in vitro and in vivo, ethanol spread instantaneously over the enamel surface. Based on these measurements, we concluded that several surfactants may be used to spread ayueous dye solutions. In a 50% mixture of water and ethanol and in pure ethanol, no surfactant is necessary for enhanced spreading of the solution, but surfactants may be considered for adhesive properties.
A Clinical Trial of Intraligamentary Anesthesia
Authors: Edwards R.W. , Head T.W. 
Published: November 2010

The effectiveness of the periodontal ligament injection in providing anesthesia for routine extractions and the possible mechanisms of action of the periodontal ligament injection in producing dental anesthesia were investigated in a clinical trial. Periodontal ligament injections were administered under strong pressure with lidocaine on 14 teeth, with epinephrine on seven teeth, and with normal saline on another seven teeth. The anesthesia attained was evaluated by: response of the teeth to an electric pulp tester, gingival probing around the teeth, and the ability for teeth to be extracted without pain. The results demonstrated that periodontal ligament injections with lidocaine were effective in providing adequate anesthesia for the performance of dental extractions. Lidocaine periodontal ligament injections were statistically and clinically more effective in attaining anesthesia than were epinephrine or saline injections. Epinephrine periodontal ligament injections resulted in a slight but statistically significant increase in the stimulus necessary to produce a patient response, when the teeth were stimulated with an electric pulp-tester. Saline injections produced no change in response to the stimulus tested. It appears, based on the results of the saline and epinephrine injections, that hydrostatic pressure had no direct effect on the production of anesthesia with the periodontal ligament injection.
Effect of Force Level on Synthesis of Type III and Type I Collagen in Mouse Interparietal Suture
Authors: Yen E.H.K. , Yue C.S. , Suga D.M. 
Published: November 2010

Nine-week-old Swiss male white mice were divided into groups killed after time intervals of force application of six h, and one, three, five, seven, ten, 14, 21, and 28 days. Each group had 45 animals: three control, three sham-operated, and three experimental animals for each of the five force levels: 50 g, 35 g, 25 g, 15 g, and 5 g. The experimental animals had helical springs placed surgically in their calvaria for expansion of the interparietal suture. The sham-operated animals received inactive springs. Control animals were at the same age as the experimental and sham-operated animals. After death, the amount of sutural expansion was measured, and the calvaria with the implanted springs were explanted into Trowelltype organ culture dishes. [ 14C]-glycine was added for two h after 60 min of culture for all explants. The rate of suture expansion was directly proportional to the force value of the tensile stress, and a maximum 2.0-mm expansion was achieved for all force levels by the 28th day. Sutural collagen was solubilized by limited pepsin digestion, and radiolabeled types I and III a-chains were separated by SDS-PAGE, visualized fluorographically, and measured densitometrically. All the experimental and sham-operated animals responded with a rapid rise followed by an almost equally rapid fall in the proportion of newly-synthesized type III collagen before becoming stabilized for the rest of the experimental period at a level that was significantly higher than that of the control and sham-treated animals of the same age. The increase in the proportion of type III collagen was directly related to force level and rate of suture expansion. The peak value of the proportion of type III collagen due to the lightest force was much closer to the proportions that occur naturally in the suture during normal rapid growth and development than to those caused by the heavier forces. Thus, it appeared that light forces tended to initiate a more physiological response than heavy forces, with respect to the proportion of newly-synthesized type III collagen.
Transient and Residual Stress in a Porcelain-Metal Strip
Authors: Asaoka K. , Tesk J.A. 
Published: November 2010

Porcelain-fused-to-metal (PFM) restorations may develop cracks during processing or in-mouth service if the relative physico-mechanical properties of the porcelain and metal are highly mismatched. Precise conditions when this might occur are not known. Many processing and property variations can affect the stresses developed throughout a porcelain-metal system. To understand this, we conducted a computer simulation of stress developed in a PFM beam. The simulation considers cooling from temperatures higher than the porcelain sag-point. The following temperature-dependent factors were incorporated: the elastic modulus, shear viscosity (porcelain), and coefficients of thermal expansion. The cooling rate dependencies of the glass transition temperature, (Tg), and the temperature distribution during cooling were also included. The results suggest that transient tensile stress at the porcelain alloy interface may result in cracks in the porcelain during cooling. Occlusal forces may set up stresses to cause cracking at the surface of the porcelain if the compressive residual stress is not high enough. PFM restorations with an alloy of high thermal expansion coefficient require rapid cooling; on the contrary, PFM restorations with the alloys of lower coefficients require slow cooling. A high cooling rate can make up for thermal expansion mismatches between the alloy and the porcelain up to 2 × 10-6/°C. Finally, the results indicated that curvature was not a sensitive indication of stress for a multimaterial beam when visco-elastic relaxation and high cooling rates are involved. For the case modeled here, curvature varied inversely with a 1/2 to 1/7th power of the stress.
Hearing-damage Risk and Communication Interference in Dental Practice
Authors: Wilson C.E. , Vaidyanathan T.K. , Cinotti W.R. , Cohen S.M. , Wang S.J. 
Published: November 2010

The use of high-speed air-turbine handpieces, operated at 300, 000 to 400, 000 revolutions per minute, has led to concern over the possibility of noise-induced hearing loss. Sound levels were measured in clinical settings and in a pre-clinical laboratory for estimation of hearing-damage risk among dentists, and the extent of communication interference. Octave-band sound pressure levels were obtained with use of a Fast-Fourier-Transform analyzer and associated instrumentation. The results of this study indicate that the sound energy contribution of a typical dental practice is about 8% to 12% of the dentist's average 24-hour noise exposure. However, noise levels during dental procedures result in an articulation index of 0.21 to 0.37, corresponding to understanding of about 18% to 48% of nonsense syllables and 52% to 90% of sentences. It appears that hearing-damage risk is slight among dentists using modern equipment. However, further noise control in handpieces is necessary so that error-free communication during dental procedures can be ensured.
Interaction of Saliva and Taste
Authors: Spielman A.I. 
Published: November 2010

In spite of the coexistence of saliva and taste in the oral cavity, an understanding of their interactions is still incomplete. Saliva has modulating effects on sour, salt, and the monosodium-glutamate-induced savory or umami taste. It has a diminishing effect on sour taste as a result of the buffering by salivary bicarbonate. It probably also contributes to the umami taste with endogenous salivary glutamate levels. Salt taste is detected only when above salivary sodium-chloride concentrations; thus saliva influences salt taste threshold levels. It also provides the ionic environment for taste cells, probably critical in signal transduction. Salivary flow rate and composition are influenced by the type of taste stimuli. In general, sour taste, elicited by citric acid or sour food, induces the highest flow rate and Na+ concentrations, while salt gives rise to high protein and Ca2+ concentrations. Stimulation with the four basic taste modalities (sour, sweet, salty, and bitter), however, does not increase the relative proportion of any of the salivary proteins. This review examines the literature on the interactions of saliva with taste, and the effect of taste on salivary composition. The possible role of the von Ebner's salivary glands and the role of saliva as a chemical cue are also discussed.
Evaluation of Alveolar Bone in Relation to Nutritional Status During Pregnancy
Authors: Clark D.E. , Navia J.M. , Manson-Hing L.R. , Duncan H.E. 
Published: November 2010

Demand for nutrients necessary for the formation of mineralized tissues increases dramatically during pregnancy to meet fetal requirements. The purpose of this clinical study was to identify short-term effects of pregnancy and dietary intakes of calcium, phosphorus, protein, and vitamin C on radiographic density and alveolar crest morphology of the mandible. Seventy-six subjects between ten and 20 weeks' gestational age were recruited from the Jefferson County, Alabama, Department of Health maternity clinic. Initially, an evaluation of their diet was done, and a single periapical radiograph was taken in the canine-premolar region of the mandible. A final evaluation of the diet and a periapical radiograph of the same teeth were obtained at a time as close to the expected date of delivery as possible. Dietary evaluation consisted of a 24-hour recall history and a food-frequency history at the two visits. Radiographs were made with a bite-block film-holding system with occlusal registration in acrylic for reproduction of projection geometry at the two visits. An aluminum stepwedge was incorporated for densitometric standardization. Measurements of plaque, and bleeding and pocket-depth probing were recorded for control of local effects on alveolar change. Standard statistical procedures of regression determined correlation of 12 nutrients and periodontal variables with bone density change and with alveolar crest morphology change. Vitamin C intakes (24-hour recall) showed a positive correlation (p = 0.033) with bone density change, and calcium intakes (24-hour recall) showed a negative, but not significant, correlation (p = 0.058) with bone density change, contributed particularly by subjects with the highest calcium intakes. The strongest relation with alveolar crest morphology change was the interproximal pocket-depth change (p = 0.086).
Properties of Alkaline Phosphatase of the Human Dental Pulp
Authors: Goseki M. , Oida S. , Nifuji A. , Sasaki S. 
Published: November 2010

Enzymatic and immunological properties of alkaline phosphatase [ALP; orthophosphoric monoester phosphohydrolase, alkaline optimum, EC 3.1.3.1.] in the human dental pulp were investigated. In inhibition and thermal inactivation studies, dental pulp ALP showed properties of universal-type ALP (kidney/bone/liver type). Dental pulp ALP cross-reacted with polyclonal and monoclonal antibodies against purified swine-kidney ALP, and with monoclonal antibody against ALP of human osteoblast-like cells in the same manner as ALPs of human bone and kidney. The sodium dodecyl sulfate-gel electrophoretic pattern showed a 140, 000-Mr native protein band. These data suggest that dental pulp ALP can be classified as a universal-type ALP having antigenic determinants common to ALP of the kidney and bone.
Salivary Flow Rates and Salivary Film Thickness in Five-year-old Children
Authors: Watanabe S. , Dawes C. 
Published: November 2010

The flow rate of unstimulated whole saliva, the volume of saliva in the mouth before (VMAX) and after (RESID) swallowing, and the surface area of the mouth were measured for determination of the average thickness of the salivary film in five-year-old children with primary dentitions. In 30 subjects of each gender, RESID was calculated from the potassium concentration in unstimulated saliva by a dilution technique. VMAX was calculated as the total of RESID plus the volume normally swallowed (the unstimulated salivary flow rate divided by the swallowing frequency). From these children, ten subjects of each gender who had no missing teeth were selected, and impressions were taken for determination of the surface area of the mouth. Aluminum foil, of known weight per unit area, was adapted to the stone models of different regions of the mouth, and the surface areas were calculated from the weights of foil. The unstimulated salivary flow rate was 0.22 ± 0.14 mL/min, the mean values of RESID and VMAX were 0.38 ± 0.11 mL and 0.50 ± 0.15 mL, respectively, and the mean total surface area of the mouth was 117.6 ± 7.6 cm2. There were no significant differences in these values due to gender. The average thickness of the salivary film in the mouth was calculated to vary between 0.06 and 0.09 mm. Although the values of salivary flow rate, RESID, and VMAX were much lower than those reported for adults, the average thickness of the salivary film was very similar to that in adults.
The Epidemiology of Root Surface Caries
Authors: Beck J. 
Published: November 2010

Although a secular decline is being seen in coronal caries in children in industrialized countries, there appears to be a relatively high prevalence of root caries, with chronologically older adults exhibiting the highest prevalences. This paper reviews the descriptive and analytical epidemiology of root caries as found in recent national, regional, and local studies. A review of the variety of study designs, populations surveyed, and epidemiologic criteria for root caries comprising recent studies is presented as a background for comparison of prevalence rates which range from 7.3% to 69.7% of the population with root decay. In the few incidence studies reported, attack rates range from 1.6 surfaces per 100 surfaces at risk to 6.3 per 1000 surface-months at risk. Risk indicators for root caries are also reviewed with studies applying multivariate techniques implicating age, fluoride, educational level, use of dental services, coronal caries, loss of attachment, and number of teeth as possible risk factors. Although incidence studies have isolated risk factors, the small number of studies result in little agreement. Risk factor models from the Iowa 65 + Oral Health Study and a Risk Indicator model from the Piedmont 65 + Dental Study are presented to illustrate the variety of factors that may be involved in the expression of root surface caries in human populations.
Prevalence and Need for Replacement of Amalgam and Composite Restorations in Dutch Adults
Authors: Kroeze H.J.P. , Plasschaert A.J.M. , van 't Hof M.A. , Truin G.J. 
Published: November 2010

In 1986, the'first nationwide epidemiological survey of adult oral health and attitudes to oral health care was carried out in The Netherlands. One of the aims of this study was to evaluate the prevalence and the quality (in terms of need for replacement) of amalgam and composite restorations in the Dutch adult population. A group of 600 dentate individuals, 20-44 years of age, was examined. Stratified cluster sampling included as factors age, gender, socio-economic status, and area of residence. Two additional parameters were studied: frequency of visiting a dentist and type of health insurance. Oral examinations consisted of direct (mirror and explorer) and indirect (color slides and bite-wing radiographs) observations with use of well-defined criteria. On average, 13.4 restorations per individual were present, of which 23.3% were classified as unsatisfactory. A great difference in prevalence and quality data was found among several types of restorations. Test results (ANOVA) for effects of age, gender, socio-economic status, area of residence, frequency of visiting a dentist, and insurance on the prevalence of (un)satisfactory restorations resulted nearly always in significant effects of only age and frequency of visits to a dentist. There was a tendency (p<0.05) for the prevalence of (un)satisfactory restorations to be higher with increasing age. For individuals visiting a dentist infrequently (once or not at all in the past two years), the prevalence of restorations was lower, and the percentage of unsatisfactory restorations was higher, in comparison with individuals visiting a dentist frequently. The two major reasons for the scoring of restorations as clinically unacceptable were approximal ledges (43%) in class II restorations and marginal (secondary) caries (57%) in all other types of restorations.
The Effect of Sucrose and Fat in Cookies on Salivation and Oral Retention in Humans
Authors: Brudevold F. , Kashket S. , Kent R.L. 
Published: November 2010

Six adults were served accurately weighed portions (about 5 g) of cookies varying in sucrose and fat content. The cookies were chewed and spat out at the time the subjects were ready to swallow. Additional spittings were collected at intervals up to two, three, and four min. Chewing time decreased with increase in sucrose, or with increase in fat. The volume of saliva in each spitting was calculated from its wet and dry weights, and it was assumed either (a) that saliva produced during chewing was not carried over in the retained food, or (b) that saliva was incorporated in the retained food in the same proportion as in the first spitting. Both approaches revealed that salivary flow rates were independent of cookie formulation, with two exceptions: (1) The cookie highest in sucrose produced a significantly higher flow rate during chewing, and (2) the fat-free cookie, which was hard to chew, elicited an elevated flow rate up to two min. The total volume of saliva for the entire experimental period was similar for all formulations, except the latter. Masticatory effects, therefore, appeared to predominate over sweetness stimulation, unless sugar content was very high. The volume of saliva in the food bolus at the time of swallowing correlated with chewing time. Oral clearance of the cookies did not give straight lines when logarithms of retained material were plotted against time. Initial clearance rates appeared to diminish with increasing sucrose and fat content of the cookies. Effects of sugars and fat on all parameters may reflect changes in cookie texture and the sizes of particles produced within the mouth.