Application Of Citric Acid Research Articles

Psychophysical and neurobiological evidence that the oral sensation elicited by carbonated water is of chemogenic origin.

The sensation produced by carbonated beverages has been attributed to chemical excitation of nociceptors in the oral cavity via the conversion of CO(2) to carbonic acid in a reaction catalyzed by carbonic anhydrase. In separate studies, we tested if the carbonic anyhdrase blocker, acetazolamide, reduced either the intensity of sensation in humans or c-fos expression by trigeminal neurons in rats, evoked by application of carbonated water to the tongue. In the psychophysical experiment, one-half of the dorsal tongue was pretreated with acetazolamide (1 or 2%), after which the tongue was exposed bilaterally to carbonated water. In a two-alternative forced-choice paradigm, subjects chose which side of the tongue yielded a stronger sensation and additionally rated the magnitude of sensation on each side. Pretreatment with acetazolamide reduced the magnitude of sensation elicited by carbonated water in a concentration-dependent manner, since a significant majority of subjects chose the untreated side of the tongue as having a stronger sensation and assigned significantly higher intensity ratings to that side. Acetazolamide did not affect the irritant sensation from citric acid, while capsaicin pretreatment reduced both the sensation elicited by carbonated water and the irritation induced by citric acid application. In a separate experiment using rats, delivery of carbonated water to the tongue significantly increased the number of cells expressing c-fos-like immunoreactivity in the dorsomedial trigeminal nucleus caudalis (versus saline controls); this was significantly reduced by pretreatment with acetazolamide. Our results support the hypothesis that carbonated water activates lingual nociceptors via conversion of CO(2) to carbonic acid; the nociceptors in turn excite trigeminal neurons involved in signaling oral irritation.

Permeability changes of dentine treated with titanium tetrafluoride

Objectives: The aim of this research was to evaluate the effect of titanium tetrafluoride on dentine permeability in comparison with sodium fluoride and acidulated phosphate fluoride to determine their contribution to acid resistance of dentine. Methods: Thirty-two dentine discs were prepared from extracted mandibular molars. The hydraulic conductance of all discs was measured before and after the formation of smear layer. The discs were then randomly divided into five experimental and one-control groups. Coronal surfaces of dentine discs were treated with either fluoride solutions of NaF, APF, 1% TiF 4, 0.5% TiF 4 and 0.1% TiF 4 or de-ionised water. Following the measurement of hydraulic conductance, treated surfaces were subjected to 25% citric acid application. Then, final permeability measurements were made. The data were statistically analysed using ANOVA and Tukey’s HSD multiple comparisons. Results: While smear layer formation considerably reduced dentinal permeability of dentine discs, fluoride or de-ionised water application to smeared surfaces did not cause any significant change in hydraulic conductance ( p>0.05). After citric acid application, control and NaF groups showed higher permeability values than 1%, 0.5% and 0.1% TiF 4 and APF groups ( p<0.01). Conclusion: Clinical use of acidic solutions of titanium tetrafluoride in dentine cavities may be considered since smeared dentine surfaces are modified to a stabile and acid-resistant state.

Does root surface conditioning with citric acid delay healing?

Effects of topical citric acid application on tissue maturation was studied in standardized periodontal defects in 6 beagle dogs. Following elevation of facial mucoperiosteal flaps, fenestration defects, 3 mm in diameter, were made through the cortical bone and recessed 0.5 mm into the dentin of maxillary canines. 1 defect in each dog was conditioned with a saturated solution of citric acid for 3 min and then rinsed with saline. Control defects in contralateral teeth were treated with saline only for the same length of time. The defects were covered with an expanded polytetrafluoroethylene membrane and the flaps repositioned and sutured. 14 days postsurgery, healing appeared more advanced along the defect walls and floor than in the center of the defect in all instances. Histometrically, citric acid-conditioned defects exhibited a higher density of collagen fibers along the defect walls and floor and adjacent to the barrier membrane as well as more advanced resolution of the residual blood clot than the surgical controls. Differences in fibroblast density within specimen pairs were non-significant. All control defects but none of the acid-conditioned defects showed an artifactual split between the dentin walls and the granulation tissue. This study failed to support the contention that topical application of citric acid to root surfaces may delay healing following periodontal surgery.

The Effect of Ultrasonic Irrigation Before and After Citric Acid Treatment on Collagen Fibril Exposure: An In Vitro SEM Study

The surface characteristics of periodontally diseased human teeth after two treatments were compared both before and after partial demineralization with citric acid. Thirteen teeth were obtained from patients with advanced periodontal disease. Three teeth were selected for control groups and 10 were used for experimental groups. All diseased root surfaces were identified and outlined. The roots were cut longitudinally into two sections. They were then scaled and root planed and the paired sections were separately classified into two control or two experimental groups. Three sections in control group 1 were rinsed by syringe with saline solution. The three sections in control group 2 were treated with ultrasonic irrigation. The 10 sections in experimental group 1 were rinsed by syringe with saline solution before and after citric acid application; the 10 sections in experimental group 2 were irrigated ultrasonically before and after citric acid application. The concentration of the citric acid was 25% (pH 1.62) and the immersion time was 3 minutes. The root samples were examined by scanning electron microscope. A significant amount of grinding debris covered on all the root surfaces in control group 1, whereas smear was removed in control group 2. The features of root surfaces of the two experimental groups differed considerably. All specimens in experimental group 2 exhibited collagen fibrils exposed as a consequence of citric acid etching. On the other hand, the smear layer was not thoroughly removed from the root surface in experimental group 1, which meant that few collagen fibrils were exposed after partial demineralization. From these results, ultrasonic irrigation before and after citric acid application improves exposure of collagen fibrils, which may be desirable for clinical success in periodontal regenerative therapy.

Effects of cadmium on the longitudinal and lateral xylem movement of citric acid through tomato stem internodes

SUMMARY Short-term experiments (2.5 h) were performed to gain insight in the effects of cadmium (Cd) on the longitudinal and lateral xylem movement of 14C-citric acid through tomato stem internodes (Lycopersicon esculentum, Mill, cv. Tiny Tim). The behaviour of citric acid was expressed by the concentrations of citric acid sorbed to the xylem walls (apparent anion exchange capacity AEC), and by the rate constant k for citric acid lateral escape. For 0.05 mM citric acid applications, the presence of 1.0 mM cadmium resulted in approximately 2-fold increases in values for apparent AEC and k; for the 9.5 mM citric acid concentrations, cadmium resulted in less than 2-fold increase in AEC, but here k did not change. In the presence of Cd, the stem-length profile of absorbed citric acid was shown to be in accordance with stem-length profiles of Cd xylem concentrations, rather than with the xylem concentrations of citric acid itself. These results were discussed in the light of the expected presence of Cd—citric acid complexes in the xylem sap; effects on k values were discussed with consideration for the possible processes of escape rate limitation in the stem.

Kinetics of the utilization of different C sources and the cellulose formation by Acetobacter xylinum

AbstractDifferent methylated glucose derivatives and cellobiose were examined as the carbon sources for growth and cellulose formation by Acetobacter xylinum. HPLC studies were carried out to gain information about the kinetics of the utilization of the C sources used. The type and yields of the synthesized cellulose were described. Besides glucose, cellobiose was a substrate for the synthesis of this polysaccharide by the bacteria. Other methylated derivatives of glucose were not accepted for a comparable synthesis of this polymer. An estimation of citrate in an unmodified culture liquid (SH medium) showed utilization in a late phase of cultivation. The influence of this organic acid on the pH value, cellulose synthesis and growth is described. By the application of citric acid as a sole carbon source “gel‐like” forms of cellulose were formed generally.

Effects of cadmium on the behaviour of citric acid in isolated tomato xylem cell walls

Effects of cadmium on the sorption of citric acid In isolated xylem cell walls were Investigated. 2.5 nM to 9.5 mM [1.5−14]crtic acid solutions were perfused through columns of xylem cell wall material, isolated from tomato plants (Lycoperslcon esculentum Mill, cv. Tiny Tim). The anion exchange potential of the column was estimated by amino acid analysis as approximately 46 meq dm whereas the apparent anion exchange capacity (AEC) was estimated as 1.65±0.18 10−4(citric acId units). This low AEC was attributed to a ‘zipper’ effect, a mutual screening of fixed R− and A+ charges. Pre-loading with 115Cd2+ did not affect citric acid sorption, indicating the absence of Cd-effects on the availability of fixed A+ charges, and the absence of the formation of effective R−-Cd2+ and Donnan tree space (DFS) (Cd(cit)H2]+ complexes. Simultaneous application of both citric acid and 115Cd2+,45Ca2+ or 28Mg2+ resufted in increased sorption of citric acid, probably due to capacity improvement rather than changes in valence-dependent anion sorption; this may be due to the presence of bulk (M(cit)H2]+, held in the column as [M(cit)H2]+ after protonation in the DFS. Sorption of citric acid was greatest in the presence of Ca2+ which was discussed in the light of the differences between Ca, Cd and Mg in their characteristics as co-ordinative M-com plexes of citric acid. The overall results indicate the potential importance of the presence of metal ions for the xylem transport behaviour of organic acids in plants.

Dentin demineralization. The effects of citric acid concentration and application time.

Preliminary work has shown that the rate of dentin demineralization increases with increasing concentrations of citric acid. This rate subsequently diminishes at much higher concentrations. The purpose of this study was to more precisely identify the citric acid concentration which produces peak dentin demineralization and to determine if this demineralization process is time dependent. Flat dentin surfaces were prepared on the buccal and lingual sides of 15 bovine molars. 8 depressions were made in each dentin surface using a #8 round bur in a high-speed handpiece with air-water coolant. Various concentrations of citric acid solutions (weight per cent) were prepared, e.g., 0%, 10%, 20%, 25%, 30%, 35%, 40%, 65% and their respective pH's recorded. 3 microliters of each citric acid solution were placed in individual depressions on the dentin surfaces and left undisturbed for 1, 2 or 3 min. Cotton pellets were used to soak up the citric acid solution, along with any dissolved calcium, and were subsequently placed in 10 ml of 18 Me omega water. The parts per million calcium found in each water sample were determined using atomic absorption spectrophotometry. Peak dentin demineralization for 1-, 2- and 3-min application times occurred at 30% (pH = 1.55), 25% (pH = 1.62) and 25% (pH = 1.62) citric acid concentrations/(pH), respectively. Dentin demineralization was found to be time-dependent for all citric acid solution concentrations. The clinical significance of these findings is discussed.

The macroscopic, microscopic and spectrometric effects of various chemotherapeutic agents on the plasma-sprayed hydroxyapatite-coated implant surface.

The purpose of this research was to determine the nature of the residual hydroxyapatite (HA)-coated implant surface after treatment with various chemotherapeutic modalities, including: citric acid, chlorhexidine gluconate, hydrogen peroxide, tetracycline HCl, stannous fluoride, polymyxin B and a prototype plastic Cavitron tip. Implant surfaces were evaluated macroscopically, microscopically (scanning electron microscopy (SEM)) and spectrometrically (energy-dispersive spectrometry and X-ray diffraction). HA-substrate bond strength and dissolution testing was also performed for surfaces treated with a supersaturated citric acid solution. All treatments left either microscopic residues or a loss of surface roughness when viewed on SEM. A 30- to 60-s application of citric acid left a significantly greater coating thickness than all other treatments, whereas a 3-min application of citric acid removed significantly more HA than untreated controls. Significant changes in Ca/P ratios were seen with most treatments. The clinical significance of this phenomenon is not known. No treatments altered the crystallinity of the residual HA coating. A 1-min application of citric acid did not significantly alter the tensile bond strength of the coating to the substrate. The clinical significance of these findings is not known at present. However, when taken with results from previous studies, it appears that in treating the infected HA-coated implant surface, a 30- to 60-s application of citric acid (pH 1) may be beneficial in detoxifying the HA coating prior to regenerative procedures. Further in vitro and in vivo studies are necessary to evaluate the biological response to citric acid when used to detoxify the infected implant surface.

In Vitro Effects of Citric Acid Application Techniques on Dentin Surfaces

The present study evaluated the in vitro effects of different application techniques of citric acid on dentin root surfaces. Ten freshly extracted, periodontally involved teeth were obtained and 4 dentin slabs, approximately 4 x 6 x 2 mm, were obtained from the roots of each tooth, for a total of 40 slabs. These slabs were identified by tooth and preserved in 1:1 anhydrous glycerol/absolute alcohol solution. Citric acid pH 1 was applied to 32 of the slabs for 5 minutes with one of 4 different techniques: 1) immersion; 2) placed with a saturated cotton pellet with no rubbing; 3) placed and burnished with a saturated cotton pellet; or 4) applied with a camel hair brush. The remaining 8 dentin slabs were used as negative control specimens, root-planed and non-acid treated. Following the various treatments, the slabs were fixed, dehydrated, critical point dried, and coated for scanning electron microscopic (SEM) evaluation. Scanning photomicrographs were obtained at 2,000, 6,000, and 40,000 magnifications. The surface characteristics of the treated dentin slabs were evaluated descriptively regarding the degree of fiber exposure; the number of exposed tubules and the surface area occupied by tubule orifices were also measured. Friedman's 2-way analysis for block designs was employed. Results demonstrated that root-planed, non-acid treated specimens had an amorphous, irregular surface which corresponded to a smear layer.(ABSTRACT TRUNCATED AT 250 WORDS)

Periodontal Healing Following Guided Tissue Regeneration With Citric Acid and Fibronectin Application

This study was undertaken to determine the effects of guided tissue regeneration (GTR) with and without citric acid conditioning and autologous fibronectin application. The study subjects were four female beagle dogs with spontaneous periodontitis. The dogs were given thorough root debridement and 4 weeks later, mucoperiosteal flaps were raised on both sides of the mandible involving the 2nd, 3rd, and 4th premolar and 1st molar teeth. After debridement, notches were placed on the roots at the level of supporting bone. Citric acid (pH 1) was topically applied for 3 minutes on the exposed root surfaces of one side (experimental). The roots were irrigated with normal saline solution. Both the root surfaces and the inner surface of the flap were then bathed in autologous fibronectin in saline. Following this, Gore-Tex periodontal material was adapted to the roots of each tooth and sutured. The contralateral side, serving as control, was treated by surgery and application of Gore-Tex periodontal material only. All membranes were removed 1 month after surgery, and the dogs sacrificed at 3 months. Both mesio-distal and bucco-lingual microscopic histological sections were evaluated by descriptive histology, and linear measurements and surface area determination of the furcal tissues were made. Periodontal healing following the use of GTR procedure resulted in an increase in connective tissue and alveolar bone regeneration. Adjunctive critic acid plus autologous fibronectin produced slightly better results, but these differences were not statistically significant for this sample.

An ultrastructural study comparing new gingival tissue attachment on chemically exposed fibrils and retained periodontal ligament.

Successful periodontal healing has been demonstrated in animals following application of citric acid to exposed root surface. However, we have been unable to achieve comparable results on clinical patients. Accordingly, the present study, using monkeys, was designed to re-evaluate the degree of interdigitation of newly-formed gingival fibrils with ones exposed to citric acid compared to normal attachment tissues of the retained periodontal ligament. We found that superficial collagen fibrils in both cases suffer degradation following normal inflammation and healing secondary to flap surgery. On retained periodontal ligament tissues, this change was limited to superficial levels and newly-formed collagen fibrils were linked immediately with old ones. In contrast, when exposed collagen fibrils were conditioned by exposure to citric acid, the degradative change occurred more deeply, and healing was delayed. Thus, the citric acid may not be the best choice of root treatments in terms of promoting better gingival tissue attachment. Furthermore, the results indicated that fibrils preserved on the root should not be curetted as possible during flap surgery as they offer an improved chance for optimal reattachment.

Citric acid burnishing of dentinal root surfaces. A scanning electron microscopy report.

The integrity of formalin-fixed periodontally diseased root surfaces was assessed following root planing to dentin and citric acid application. Extracted human teeth (fixed in 10% formalin), with crowns removed, were vertically sectioned in half. A horizontal groove on each proximal surface marked the extent of attachment loss. The diseased root surface was vigorously root planed to expose dentin. Cotton pellets, soaked in a saturated solution of citric acid, were either "placed" (control) or "burnished" (vigorously rubbed using root planing pressure) (experimental) on the prepared root surface for 5 min. Pellets were changed 2 times/min. The teeth were fixed and prepared for scanning electron microscope viewing and photography. A representative print was selected for each specimen. To confirm differences between test and control groups, untrained raters were asked to perform 2 sorting exercises. First, they were asked to sort the representative photographs of each specimen into 2 piles based on surface characteristics. Second, they were asked to choose from pairs of photographs, representing matched specimens, the one photograph which appeared to have the greatest collagen surface area. The surfaces of experimental specimens revealed patent dentinal tubules and an intertubular area with a very distinct "shag carpet" appearance of deeply tufted collagen fibrils. Control samples also exhibited open dentinal tubules, yet the intertubular surface displayed a "matted collagen" surface. Results of the 2 sorting exercises confirm that burnishing of formalin-fixed dentin root surfaces for 5 min with cotton pellets soaked in a saturated solution of citric acid consistently produces a distinct tufted collagen fibril surface.(ABSTRACT TRUNCATED AT 250 WORDS)

歯肉剥離掻は手術後の新付着に関する研究 脱灰掻はセメント質に対する歯肉付着について

Since endotoxin may be absorbed only in the superficial layer of cementum leaving the deep cementum unchanged morphologically, the cementum of teeth with periodontal involvement was examined. The author considered that the application of citric acid after curetting of only the superficial cementum was better root treatment than complete removal of the cementum. The aim of this study was to examine histological events during the formation of new fibrous attachment to demineralized cementum after flap surgery following citric acid treatment in fifteen dogs. The demineralized cementum prevented the apical proliferation of junctional epithelium. The fibroblasts apposed to the exposed cemental collagen produced numerous new fibrils. Furthermore, the newly-formed collagen fibrils appeared to link with the exposed ones. These findings suggest that this root treatment would facilitate the formation of new fibrous attachment.

Collagen linkage in periodontal connective tissue reattachment. An ultrastructural study in beagle dogs.

Early stages of connective tissue reattachment to surgically denuded cementum and root dentin following citric acid application were studied in fenestration wounds. Block specimens were obtained after seven, 14, and 21 days. Continuity between newly deposited collagen fibrils in the granulation tissue and unmasked dental matrix collagen had been established within seven days by interdigitation of fibrils in an up to 0.5 micron-wide zone at the cementum or dentin surface. Splicing of collagen at the fibrillar level by direct attachment to the severed end of matrix fibrils or by juxtapositioning of new and old fibrils was seen in rare instances only. At 14 and 21 days, distinct bundles of collagen fibrils inserted deeply into the orifice of dentinal tubules. Arrested and reversed surface resorption was encountered at all time points. At these sites as well, new collagen fibrils interdigitated with denuded matrix collagen, while some resorbed surfaces were characterized by absence of collagen continuity. The results lend continued support to the concept of reattachment based on interdigitation of collagen fibrils. However, since attachment is established even in the absence of this feature, a significant role for specific attachment substances not shown can also be postulated.

Pulpal response to topical application of citric acid to root dentin.

Abstract The purpose of the present study was to investigate the pulpal reactions to citric acid (pH 1.0) applied for 3 min to exposed root dentin. We used 48 roots of 24 maxillary and mandibular third and fourth permanent premolars from dogs divided equally into experimental (citric acid) and control (saline) roots. Following surgical exposure of the buccal root surface and the removal of the cementum with a Gracey curette, citric acid or saline was applied on the exposed dentin. The pulpal reactions were histologically evaluated 1, 7 and 15 days postoperatively using hematoxylineosin stained sections. Results obtained from 43 specimens showed no difference in the pulpal response at any of the observation intervals between citric acid and saline‐treated teeth.

Biological treatment of periodontally involved root surfaces. The effect of citric acid and fibronectin application

Biological treatment of periodontally involved root surfaces. The effect of citric acid and fibronectin application

The formation of a connective tissue attachment after the application of citric acid and fibrin adhesive

The formation of a connective tissue attachment after the application of citric acid and fibrin adhesive

The effectiveness of citric acid as an adjunct to surgical re-attachment procedures in humans.

The purpose of this study was to clinically evaluate the effect of citric acid on re-attachment and re-adaptation in conjunction with periodontal surgery. A split-mouth design was used in 10 patients involving 30 quadrants of surgery. A total of 120 teeth were treated. Each quadrant consisted of at least 2 teeth from cuspid to second molar. One quadrant was treated with a modified Widman flap alone while the root surfaces of the contralateral side were also treated with a 3 min application of citric acid. Immediately following hygienic phase and at 3 and 6 months postsurgically, the following measurements were taken in this sequence: gingival index, gingival crevicular fluid flow, plaque index, furcation involvement, level of attachment and probing depth. All the data were statistically analyzed using the paired t-test, chi 2 and Fisher exact probability test. The biometric results showed that both surgical techniques resulted in a loss of attachment in shallow pockets and a gain in deeper pockets. Both techniques resulted in similar amounts of recession and probing depth reduction at 6 months. Gingival index, plaque index and furcation values decreased at 3 and 6 months postsurgically. The gingival crevicular fluid values remained essentially the same up to 6 months postsurgically.

Autonomic mechanisms underlying capsaicin induced oral sensations and salivation in man.

The effects of capsaicin, citric acid and nicotine applied to the apex or radix of the tongue on taste sensations and salivation were studied in relation to the presence of substance P immunoreactive neurones in man. Application of capsaicin (30 micron) to the apex of the tongue or to the palatinal mucosa, but not to the radix of the tongue, caused a reproducible burning sensation and salivation from the submandibular-sublingual and parotid glands. The salivation response to capsaicin was reduced by methylscopolamine pretreatment. Similar levels of substance P immunoreactivity were present in the lingual apex and radix area (including vallate papillae) of man, while in the cat about 4 times higher levels of substance P immunoreactivity were present in the vallate papillae than in the lingual apex. Immunohistochemistry showed that in the cat many substance P immunoreactive nerves were associated with the taste buds of the vallate papillae, while in man substance P immunoreactive fibres were only seen penetrating into the epithelium of the lingual apex. In addition some subepithelial blood vessels in all regions were surrounded by substance P immunoreactive nerves in both cat and man. Citric acid application to the tongue apex caused both submandibular-sublingual and parotid salivary secretion concomitant with a burning sensation. Salivary secretion was also seen after citric acid application to the radix of the tongue. This response was associated with a sour taste. The salivation response to citric acid was not significantly reduced by methylscopolamine pretreatment. Lingual apex application of nicotine was associated with a sweet taste and a small rise in salivary secretion rate. This response was not significantly reduced by methylscopolamine. In conclusion, the sensitivity to capsaicin of the human tongue is restricted to the apex portion. This is in parallel with the occurrence of intraepithelial substance P immunoreactive nerve fibres. Capsaicin induced salivary secretion seems mainly to be mediated via parasympathetic, cholinergic reflex mechanisms. Citric acid and nicotine induced salivation responses are comparatively more resistant to methylscopolamine pretreatment.