Biomedical subjects

W Buchalla

Publications and source records attributed to W Buchalla.

At least 19 recordsLinked to original sources

PubMed2006

Deposition of fluoride on enamel surfaces released from varnishes is limited to vicinity of fluoridation site.

The aim of the in-situ study was to determine fluoride uptake in non-fluoridated, demineralized enamel after application of fluoride varnishes on enamel samples located at various distances from the non-fluoridated samples. All enamel samples used were demineralized with acidic hydroxyethylcellulose before the experiment. Intra-oral appliances were worn by ten volunteers in three series: (1, Mirafluorid, 0.15% F; 2, Duraphat, 2.3% F and 3, unfluoridated controls) of 6 days each. Each two enamel samples were prepared from 30 bovine incisors. One sample was used for the determination of baseline fluoride content (BFC); the other was treated according to the respective series and fixed in the intra-oral appliance for 6 days. Additionally, from 120 incisors, each four enamel samples were prepared (one for BFC). Three samples (a-c) were placed into each appliance at different sites: (a) directly neighboured to the fluoridated specimen (=next), (b) at 1-cm distance (=1 cm) and (c) in the opposite buccal aspect of the appliance (=opposite). At these sites, new unfluoridated samples were placed at days 1, 3 and 5, which were left in place for 1 day. The volunteers brushed their teeth and the samples with fluoridated toothpaste twice per day. Both the KOH-soluble and structurally bound fluoride were determined in all samples to determine fluoride uptake and were statistically analyzed. One day, after fluoridation with Duraphat, KOH-soluble fluoride uptake in specimen a (=next) was significantly higher compared to the corresponding samples of both the control and Mirafluorid series, which in turn were not significantly different from each other. At all other sites and time points, fluoride uptake in the enamel samples were not different from controls for both fluoride varnishes. Within the first day after application, intra-oral-fluoride release from the tested fluoride varnish Duraphat leads to KOH-soluble fluoride uptake only in enamel samples located in close vicinity to the fluoridation site.

Adult↗

PubMed2006

The ability of selected oral microorganisms to emit red fluorescence.

Some novel caries detection and excavation devices rely on the ability of bacteria to produce red fluorescing compounds. The aim of this study was to examine the ability of selected oral microorganisms to emit red fluorescence. Streptococcus mutans, S. oralis, S. salivarius, S. sobrinus, Lactobacillus fermentans, L. casei, L. rhamnosus, Actinomyces naeslundi, A. israelii, Prevotella intermedia, and Fusobacterium nucleatum were inoculated onto Columbia agar with haemin and vitamin K and incubated anaerobically for up to 7 days in the dark. The resulting bacterial colonies were excited using filtered xenon light (405 +/- 20 nm) and digitally photographed through a 530-nm high-pass filter. The red and green portions of the colony fluorescence were analyzed using a computer program and the red/green ratio was calculated. All colonies emitted both red and green fluorescence. The green outweighed the red portion for the following species (in descending order) S. oralis, S. salivarius, S. mutans, F. nucleatum and S. sobrinus. The red portion was higher for the following species (in descending order) P. intermedia, A. naeslundi, A. israelii, L. fermentans, L. rhamnosus and L. casei. With all the bacteria examined, one color portion generally outweighed the other, giving the visual impression of either red or green fluorescence. We conclude that red fluorescence is well suited to detection of the bacteria which cause dentin caries but it is not suitable as an indicator of the presence and activity of the streptococci involved in initial caries.

Bacteria, Anaerobic↗

PubMed2006

Prevention of erosion and abrasion by a high fluoride concentration gel applied at high frequencies.

The aim of this study was to determine maximum attainable protection of enamel from erosion and erosion abrasion using a highly fluoridated gel with and without additional fluoride from toothpaste. Thirty-six bovine enamel specimens were subjected to six erosive attacks per day (1% citric acid with pH 2.3 for 30 s), while the rest of the day the specimens were in artificial saliva. There were four treatment groups (9 specimens in each group): fluoride-free toothpaste/saliva slurry twice daily (group T0), fluoride-containing toothpaste/saliva slurry twice daily using 1,250 ppm F toothpaste (group TF), fluoride-containing toothpaste/saliva slurry twice per day plus application of a highly fluoridated gel (12,500 ppm F) twice a day for 120 s (group 2F) and a group with gel application 8 times a day (group 8F). Additionally, half of each specimen in all groups was subjected to brushing abrasion during application of the toothpaste/saliva slurry. Brushing abrasion alone led to no observable enamel loss measured with profilometry. After 14 days of cycling of erosion without toothbrushing abrasion, high-fluoride gel application 2 or 8 times daily showed significantly less enamel loss (median 24/19 microm) than with toothpaste with or without fluoride (41/45 microm). After 14 days of cycling of erosion and toothbrushing abrasion, gel application 2 or 8 times daily (33/29 microm) showed significantly less enamel loss than toothpaste with or without fluoride (57/62 microm). We conclude that a highly fluoridated acidic gel is able to protect enamel from erosion and toothbrushing abrasion while fluoridated tooth paste provides little protection.

Amines↗

PubMed2006

Effect of a casein/calcium phosphate-containing tooth cream and fluoride on enamel erosion in vitro.

The aim of this study was to determine whether a tooth cream containing casein/calcium phosphate (CasCP) protects enamel against erosion. Sixty bovine enamel specimens were prepared for profilometry and distributed into five groups. Specimens were rinsed with artificial saliva interrupted by 1% citric acid (pH 2.3) for 30 s 6 times daily for 14 days. Group 1 (n=12) was not treated (control); in group 2 (n=12) CasCP was applied for 120 s twice daily; in group 3 (n=12) 250 ppm fluoride as NaF was applied for 120 s twice daily; in group 4 (n=12) CasCP was applied for 120 s, then 250 ppm fluoride for 120 s twice daily, and in group 5 (n=12) amine fluoride (AmF) gel (12,500 ppm fluoride) was applied for 120 s twice daily. Differences between groups with respect to erosive enamel loss (profilometrically determined depth after 7 and 14 days) were tested by the Mann-Whitney test (alpha=0.05). After 7/14 days' erosive cycling, specimens treated with AmF gel showed significantly less enamel loss (18.5/35.5 microm; medians) than those treated with CasCP (25.5/46.9 microm), 250 ppm fluoride (25.0/ 40.9 microm), CasCP and 250 ppm fluoride (23.9/47.4 microm) or with no treatment (26.3/49.8 microm). It is concluded that highly fluoridated acidic AmF gel can protect enamel against erosion while CasCP, 250 ppm fluoride or a combination of CasCP and 250 ppm fluoride provide little protection.

Amines↗

PubMed2005

Suitability of a malachite green procedure to detect minimal amounts of phosphate dissolved in acidic solutions.

The study describes the suitability of a colorimetric method (malachite green procedure) for detection of minimal amounts of phosphate (7.3-29.1 micromol/L) in different acidic solutions (hydrochloric acid, oxalic acid, maleic acid, perchloric acid, tartaric acid, citric acid, lactic acid and acetic acid) adjusted to pH 2.0. A mixture of the respective phosphate concentrations with distilled water served as control. The experiments were run with ten repeats in series. Assessment of intra- and interassay coefficient of variation and lower limit of quantification revealed that depending on the acid used, the applied method is a reliable and suitable tool to detect and quantify minimal phosphate contents in small samples of acidic solutions that have the potential to cause erosive dental lesions.

Acids↗

PubMed2005

Enamel fluoride uptake of a novel water-based fluoride varnish.

Aim of the in situ-study was to evaluate fluoride retention in sound and demineralised enamel after application of a novel water-based fluoride (0.12% F) varnish Mirafluorid (Hager and Werken, Germany) compared to the resin-based varnish (2.26% F) Duraphat (Colgate, USA). Each five enamel specimens were prepared from 60 bovine incisors. In 150 of these specimens, incipient lesions were produced with acidic hydroxyethylcellulose (pH 4.8; 72 h), 150 specimens were not demineralised. The samples were equally (n=100) allotted to three groups (A: Mirafluord, B: Duraphat, and C: control). Each 80 specimens (40 demineralised and 40 sound) were varnished with either Mirafluorid or Duraphat or remained unfluoridated (controls). The other specimens were used for measuring base-line fluoride content of the respective tooth. Each six specimens (three demineralised and three sound) were fixed in intraoral appliances worn for 5 days by 10 volunteers in three series (A-C). During the experiment, the samples were brushed twice daily with fluoridated toothpaste. KOH-soluble and structurally bound fluoride (0-30 and 31-60 microm depth) was determined immediately, 1, 3 and 5 days after fluoridation. Fluoride uptake was calculated as compared to base-line content and statistically analysed. Immediately after fluoridation, uptake of KOH-soluble and structurally bound fluoride was similar for Mirafluorid and Duraphat in both demineralised and sound enamel. However, at day 1, 3 and 5 statistically significantly higher amounts of KOH-soluble and structurally bound fluoride were found in the samples treated with Duraphat. For Mirafluorid only the uptake for KOH-soluble fluoride and structurally bound fluoride in the first enamel layer (0-30 microm) of the demineralised samples was significantly higher compared to the controls (C). It is concluded that the novel fluoride varnish Mirafluorid deposits less KOH-soluble and structurally bound fluoride on both demineralised and sound enamel compared to Duraphat under in situ-conditions.

Adult↗

PubMed2005

Impact of modified acidic soft drinks on enamel erosion.

OBJECTIVE: To evaluate the enamel erosive potential of modified acidic soft drinks under controlled conditions in an artificial mouth. MATERIALS AND METHODS: From each of 144 bovine incisors one enamel sample was prepared. Labial surfaces of the samples were ground flat, polished and covered with adhesive tape, leaving an exposed area. The samples were distributed among four (A-D) groups for treatment with A: Coca-Cola, B: Sprite; C: Sprite light, D: orange juice. Either 1.0 mmol l(-1) calcium (Ca) or a combination (comb.) of 0.5 mmol l(-1) calcium plus 0.5 mmol l(-1) phosphate plus 0.031 mmol l(-1) fluoride was added to the beverages. Samples of each group were subdivided into three subgroups (-original; -Ca and -comb.) for treatment with original and modified drinks. De- and remineralization cycles were based on a standard protocol described earlier. Surface loss of the specimens was determined using profilometry after test procedure. RESULTS: In all subgroups, loss of enamel was observed. The enamel loss recorded for the samples rinsed with original Sprite and original orange juice was significantly higher compared with all other solutions (P = 0.001). Lowest enamel loss was recorded for the original Coca-Cola group (P = 0.001). With the exception of Coca-Cola, demineralization with the modified beverages led to significantly lower losses compared with the respective original solutions. CONCLUSION: Modification of the test soft drinks with low concentrations of calcium or a combination of calcium, phosphate and fluoride may exert a significant protective potential with respect to dental erosion.

Animals↗

PubMed2004

Fluorescence spectroscopy of dental calculus.

BACKGROUND: Correct diagnosis of the presence and extent of subgingival calculus is important for periodontal treatment planning and reassessment after periodontal therapy. Traditional tactile methods often lack sensitivity. The present investigation shall contribute to understanding the fundamental fluorescence properties that may be useful for optical detection of both supra- and subgingival calculus. OBJECTIVES: The aim of this study was to investigate emission spectra from supra- and subgingival calculus under a wide range of excitation wavelengths. METHODS AND RESULTS: Extracted human molars with either supragingival or subgingival calculus deposits on the root surface were selected (n = 3 each). Emission spectra were recorded from the calculus of each tooth and corresponding areas of clean root surfaces using a fluorescence spectrophotometer at excitation wavelengths from 360 nm up to 580 nm in steps of 20 nm. The spectra were corrected for the wavelength dependent instrument sensitivity and normalized to peak intensity (the highest peak was set at 1.0). Emission spectra of calculus exhibited distinct fluorescence bands between 570 and 730 nm not present in clean root surfaces. This fluorescence emission was strongest for excitation wavelengths from 400 to 420 nm. No differences were observed between supra- and subgingival calculus. CONCLUSIONS: Human dental calculus can clearly be differentiated from clean root surfaces by emission spectrophotometry. The characteristic fluorescence emission of supra- and subgingival calculus may be due to a variety of porphyrin derivatives and may provide the basis for future diagnostic procedures.

Dental Calculus↗

PubMed2003

Effect of mineral supplements to citric acid on enamel erosion.

The aim of this study was to evaluate the effect of mineral supplements to citric acid (1%; pH 2.21) on enamel erosion under controlled conditions in an artificial mouth. From each of 156 bovine incisors one polished enamel sample was prepared. The samples were divided among 13 experimental groups (n=12). In group 1 citric acid only was used (control). In groups 2-10 either calcium, phosphate or fluoride in various low concentrations was admixed to the citric acid. In groups 11-13 the citric acid was supplemented with a mixture of calcium, phosphate and fluoride. For demineralisation the specimens were rinsed with the respective solution for 1 min, immediately followed by a remineralisation period with artificial saliva (1 min). The specimens were cycled through this alternating procedure five times followed by rinsing for 8 h with artificial saliva. The de- and remineralisation cycle was repeated three times for each specimen interrupted by the 8 h-remineralisation periods. Before and after the experiments, the specimens were examined using microhardness testing (Knoop hardness) and laser profilometry. Hardness loss and enamel dissolution was significantly higher for the controls as compared to the remaining groups. Significantly lowest hardness loss for all groups was recorded for group 12 with admixture of calcium, phosphate and fluoride to citric acid. The significantly highest enamel loss was recorded for the controls compared to all other samples. Groups 3 and 4 revealed significantly lower and higher tissue loss compared to the remaining groups (2-13), respectively. The other groups did not differ significantly from each other. Modification of citric acid with calcium, phosphate and fluoride exerts a significant protective potential with respect to dental erosion. However, with the low concentrations applied enamel dissolution could not be completely prevented.

Animals↗

PubMed2003

Influence of tea on intrinsic colour of previously bleached enamel.

Aim of the study was to evaluate the influence of tea applied at various time intervals after bleaching of enamel on intrinsic tooth colour. Ninety bovine specimens were distributed among six groups (A-F, n=15). The samples of group A-D were bleached with the 10% carbamide peroxide (CP) gel VivaStyle for 8 h, followed by storing in artificial saliva for the remaining period of the day. The specimens were removed from the saliva at different intervals (A: 0 min, B: 60 min, C: 240 min) and immersed in freshly prepared black tea for 10 min. Group D (bleaching, no tea), E (no bleaching, but tea) and F (no bleaching, no tea) served as controls. These procedures were repeated for 8 days. Colour was measured at baseline, after each day, and after final cleaning using the CIELab-system. Then Deltab (initial b-value - final reading), DeltaL, and composite colour (DeltaE) were statistically analysed. External bleaching (A-D) led to a distinct whitening effect with lower Deltab- (=reduction in yellow) and higher DeltaL-values (=increase in brightness) compared with controls. The Deltab- and DeltaL-values of the samples A-C were not significantly different from the samples which were bleached only. No significant difference was observed comparing specimens of group A-C. It is concluded that application of tea directly after bleaching with 10% CP does not significantly effect the outcome of a bleaching treatment irrespective of the time interval elapsed between the bleaching procedure and the contact of the tooth surface with tea.

Animals↗

PubMed2002

Electronic determination of root canal length in primary teeth with and without root resorption.

AIM: To test an electrical device for determining root canal length in primary teeth in vitro, and to compare it with the radiographic length measurement. METHODOLOGY: Two examiners determined the root canal length of 24 extracted maxillary primary incisors (12 with visible root resorption and 12 without) using an electrical root canal meter (Tri Auto ZX, Morita, Dietzenbach, Germany). The instrument was left in the root canal after the second examination and a radiograph was taken. The whole tooth was cleared by immersion in methylsalicylate and subsequently photographed. Both radiographs and photographs of cleared teeth were measured and compared with the electronic measurements. RESULTS: The evaluation of the radiographs showed a mean distance between the instrument tips and apices of 0.60 (+/- 0.41) mm; evaluation of the cleared teeth showed an equivalent distance of 0.62 (+/- 0.40) mm. The mean distance between instrument tip and acceptable working length (determined with the clearing method) was 0.26 (+/- 0.24) mm in teeth without resorption and 0.29 (+/- 0.30) mm in teeth with resorption. CONCLUSION: The presence of resorption in primary teeth did not affect the accuracy of electrical measurement of root canal length in vitro. The application of this method in primary teeth should be evaluated further.

Confidence Intervals↗

PubMed2002

Clinical evaluation of the cleansing properties of the noninstrumental technique for cleaning root canals.

AIM: The purpose of the present study was to evaluate noninstrumentation technology (NIT) for root-canal cleansing in vivo. METHODOLOGY: A total of 22 teeth that were to be extracted in 18 patients were treated with NIT for 30 min with 3.0% NaOCl. After extraction, the remaining organic debris in the root canals was evaluated histologically and categorized as the percentage of the corresponding canal length in the apical middle and coronal regions of the roots. Percentage of residual debris was categorized as follows: D1, 0%; D2, 1-50% and D3, 51-100%. RESULTS: In the coronal region, 55% of the roots were totally clean (Dl), whereas 12% and 33% were scored as D2 and D3, respectively. The middle section was evaluated as D1 in 27%, D2 in 18% and D3 in 55%. In the apical region, only 21% of the roots were totally cleaned: the remaining 79% were scored as D3. CONCLUSION: The results indicate that the noninstrumental technique for cleaning root canals needs further modifications for achieving acceptable results under clinical conditions.

Chi-Square Distribution↗

PubMed2002

Fluoride uptake, retention, and remineralization efficacy of a highly concentrated fluoride solution on enamel lesions in situ.

Repeated topical application of concentrated fluorides is known to reduce caries. Little is known about fluoride retention and remineralization in incipient caries lesions following a single application. We investigated fluoride and the remineralization kinetics of a single application of elmex fluid (GABA International AG, Münchenstein, Switzerland; 10,000 ppm F) in initial enamel lesions. In this double-blind, placebo-controlled, randomized, crossover in situ study that conformed to good clinical practice, volunteers received intra-oral removable appliances carrying demineralized enamel samples after application of elmex fluid or placebo. After 5 min, 1, 2, 3, and 4 weeks in situ, KOH-soluble fluoride (KOHF), structurally bound fluoride (SBF), mineral gain, and lesion depth reduction were measured. Elmex fluid promoted higher KOHF and SBF at all times, decreased KOHF with time, increased SBF up to 3 weeks, and registered a higher mineral gain than placebo. Volunteers with higher stimulated salivary flow rates had lower fluoride uptake, but higher mineral gain. In conclusion, a single application of highly concentrated fluoride solution increases remineralization.

Adolescent↗

PubMed2001

In vitro evaluation of different remineralization periods in improving the resistance of previously eroded bovine dentine against tooth-brushing abrasion.

One dentine specimen was prepared from each of 90 bovine incisors. The samples were then evenly distributed among nine groups (A-I) and submitted to 10 alternating de- and re-mineralization cycles, including abrasion by tooth brushing. Each cycle started with a demineralization using the erosive soft drink Sprite Light for 1 min, followed by storing the samples in pooled human saliva for a total of 240 min. The specimens were removed from the saliva at different intervals (group A, 0 min; B, 15 min; C, 30 min; D, 45 min; E, 60 min; F, 90 min; G, 120 min) and brushed in an automatic brushing machine. Groups H (erosion, but no brushing) and I (no erosion, but brushing), which were also stored in saliva for 240 min, served as controls. After these cycles, loss of dentine was determined by profilometry, producing the following values (mean+/-S.D.), which were analysed statistically (P< or = 0.05): group A (5.03+/-1.49 microm), B (4.44+/-1.09 microm), C (4.91+/-0.95 microm), D (5.47+/-1.52 microm), E (5.29+/-1.45 microm), F (4.76+/-0.74 microm), G (5.16+/-0.71 microm), H (2.61+/-1.31), I (1.11+/-0.39). Groups A-G had no significant differences, but they showed a significantly greater loss of dentine than groups H and I. It is concluded that the abrasion resistance of eroded bovine dentine is still decreased after a remineralization period of 120 min.

Analysis of Variance↗

PubMed2001

Three-year follow up assessment of Class II restorations in primary molars with a polyacid-modified composite resin and a hybrid composite.

PURPOSE: To evaluate the 3-year success rate of Class II restorations in primary molars performed with Compoglass, a polyacid-modified resin-based composite (compomer) and TPH-Spectrum, a hybrid resin-based composite. MATERIAL AND METHODS: In a dental practice, in each of 52 children at least two primary molars were restored. 96 primary molars were restored with TPH-Spectrum using the total-etching-technique and 94 with Compoglass without acid etching prior to application of the bonding adhesive. The restorations were assessed at baseline (1996) and after 1 and 2 yrs according to the Ryge criteria. After 3 yrs the restorations (46 Compoglass, 46 TPH-Spectrum) of 35 children were re-evaluated. RESULTS: After 3 yrs the cumulative success rate according to the Kaplan-Meier-estimation was 79.5% for the Compoglass and 85.8% for the TPH-Spectrum restorations. No significant differences were observed between the two materials with respect to color matching, cavosurface discoloration, anatomic form, margin integrity and caries assessment. The present investigation revealed that TPH-Spectrum and Compoglass are suitable materials for restoring primary molars. CLINICAL SIGNIFICANCE: After an observation period of 3 years, both TPH-Spectrum and Compoglass demonstrated acceptable clinical results.

Acid Etching, Dental↗

PubMed1999

Effect of toothbrushing on fluoride release of polyacid-modified composite resins.

The aim of the study was to evaluate the fluoride release of polyacid-modified composite resins (Dyr-act, Compoglass) submitted to brushing abrasion. Twenty samples were taken from each material and stored in a buffer solution (pH 4.0) for 12 days. Each day, the samples were transferred to a fresh solution. Ten samples of each material were brushed in an automatic tooth-brushing machine (250 strokes, 260-g load) every fourth day. The remaining samples were not subjected to brushing. Fluoride content of the solutions was measured with a fluoride sensitive electrode after the addition of TISAB. Statistical analysis demonstrated significant differences between the two materials with regard to cumulative fluoride release within the 12 days of the experiment. However, no difference was observed between the fluoride release of the brushed samples compared to the unbrushed specimens. This was true for both, the cumulative fluoride release and its release on the day following brushing. It is assumed that regular brushing of the tested materials did not influence their release of fluoride and that brushing of polyacid-modified composite resins does not lead to maintaining their initially high level of fluoride release.

Analysis of Variance↗

PubMed1999

Fluoride release/uptake of polyacid-modified resin composites (compomers) in neutral and acidic buffer solutions.

The aim of the present study was to evaluate the fluoride uptake/release of polyacid-modified resin composites (compomers) in neutral and acidic buffer solutions. Two compomers (Dyract and Compoglass) were tested and the conventional glass-ionomer cement (GIC) Vivaglass Base served as a control. Forty specimens were fabricated from each of the respective materials. Twenty of these specimens were placed in artificial saliva and the other 20 specimens in a fluoridated dentifrice slurry for 5 min. Then, 10 fluoridated and 10 non-fluoridated specimens were immersed in a neutral buffer solution (pH 6.8), and the other specimens were immersed in an acidic solution (pH 4.0). After 1, 2, 3, 4, and 5 days the samples were again placed in either a fluoridated dentifrice slurry or saliva for 5 min, after which time they were transferred to fresh buffer solutions. The fluoride content of the solutions was assessed with a fluoride sensitive electrode. Fluoride release from all the materials decreased continuously during the experiment, with a significantly higher release in the acidic solution compared to the neutral buffer solution. Fluoridation did not result in an increased fluoride release for the compomers. However, the conventional GIC revealed a significantly higher fluoride release after fluoridation. It is concluded that Dyract and Compoglass can not be replenished with fluoride, irrespective of the pH value of the environment.

Analysis of Variance↗

PubMed1998

Toothbrushing abrasion of polyacid-modified composites in neutral and acidic buffer solutions.

STATEMENT OF PROBLEM: Polyacid-modified composites are recommended for use in lesions that are subjected to toothbrushing abrasion and acidic challenges, such as cervical lesions. There is little information whether these materials are able to withstand degradation due to erosive attacks and toothbrushing abrasion. PURPOSE: This study evaluated the resistance of polyacid-modified composites against toothbrushing abrasion under acidic and neutral conditions. METHODS: Forty specimens fabricated of each of two polyacid-modified composites (Dyract, Compoglass) were investigated. For each composite group, 20 specimens were placed in a neutral solution (pH: 6.8) and 20 specimens were placed in an acidic solution (pH: 3.0) for 24 hours. All specimens were brushed in an automatic toothbrushing machine, then subjected to storage in the respective buffer solution (8 hours), followed by brushing three times. Abrasion was determined profilometrically. RESULTS: For both materials, abrasion in the acidic environment was significantly higher compared with neutral conditions. Thus, Compoglass composite demonstrated a lower abrasion resistance than Dyract composite. CONCLUSION: The abrasion resistance of the investigated materials was reduced under acidic conditions.

Acids↗