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PubMed2003

Copper ions inhibit the demineralisation of human enamel.

Cu2+ is cariostatic in rats reportedly due to it bacteriocidal properties. Here, we report the use of a simple abiotic model system to investigate whether Cu2+ has any inhibitory effect on the acid dissolution of human enamel. Crowns were exposed to a sequence of seven 10 mmol/l acetic acid challenges. The mineral dissolved during each challenge was then determined. CuSO4 (10 mmol/l) was present during the fourth of these challenges. Loss of calcium and phosphate were reduced by 57 and 63%, respectively, (P<0.0001) in the presence of Cu2+. Losses were also significantly reduced during the next acidic challenge in the absence of Cu2+. The degree of protection was found to approach maximum at about 5 mmol/l Cu2+. The well-known cariostatic properties of Cu2+ may therefore be due not only to its ability to inhibit bacterial growth but also to its ability to directly inhibit acid dissolution of enamel.

Acetic Acid↗
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↗
PubMed2000

The effect of sucrose diet of rat dams on the dentine apposition and dental caries of their pups.

The purpose was to examine whether a sucrose diet in rat dams reduces dentine apposition and enhances dental caries in their pups. Sprague-Dawley rat pups were randomized into four groups on the day of birth. During the lactation period three dams received a standard rodent diet and three a diet containing 41% sucrose. At the age of 3 weeks the pups were weaned and given an intraperitoneal injection of oxytetracycline hydrochloride. During the experimental period, half of the pups of control dams received a sucrose diet (Cnt-Suc pups) and half of the pups of sucrose dams received a standard diet (Suc-Cnt pups). The pups in the other halves received the same diet as given to their dams during lactation (Cnt-Cnt and Suc-Suc pups). Urine samples were collected from dams and pups during the test periods. After 4 weeks the pups were killed, their blood was collected and their jaws sectioned sagittally. Dentine apposition was determined planimetrically and dental caries using Schiffs staining. Ca, K and Na of serum and urine were measured flame photometrically and P using an ultraviolet method. The lactational sucrose diet was associated with decreased P and Na excretion in the dams, and also with reduced dentine apposition in their pups. Reduced dentine apposition and induced Ca excretion with decreased P, K and Na excretions were observed in Suc-Suc pups and Cnt-Suc pups during the experiment period. Fewer intact teeth with more enamel and dentinal caries lesions occurred in sucrose-exposed groups (Suc-Cnt, Cnt-Suc and Suc-Suc pups). It was concluded that the sucrose diet given to dams during lactation changed the function of the pulp dentine complex of their pups leading to reduced dentinogenesis, but also predisposed to a reduction of dentinogenesis in pups during the experimental period and enhanced the occurrence of dental caries.

Analysis of Variance↗
PubMed2002

Resistance of an enamel-bonding agent to saliva and acid exposure in vitro assessed by liquid scintillation.

OBJECTIVES: To determine the leakage and resistance of a bonding agent and a light-curing fine hybrid composite when exposed to saliva or lactic acid (pH 4) in vitro. METHODS: Twenty discs in each of four groups of selected irradiated bovine lower central incisors were treated with one of three sealing options: an enamel bond (Heliobond, Vivadent, Schaan, Liechenstein) in a single-step application; Heliobond in a two-step application; and Tetric Flow (Vivadent) as the negative control. One group served as the positive control and remained unsealed. Loss of apatite was determined using the radiochemical method of liquid scintillation. The Cherenkov radiation was assessed in order to evaluate the acid resistance and leakage of smooth surface enamel bonding after exposure to saliva and lactic acid. In addition, replicas were made for SEM analysis of micromorphologic surface changes. RESULTS: A mean loss of 416.5 g (s.d. 57.0) apatite was observed over the unsealed sites following 14 days of exposure to lactic acid. The application of Heliobond in a one- and two-step application still revealed a remarkable degree of leakage, and substance losses of 196.5 g (s.d. 38.9) and 161.8 g (s.d. 39.7), but a protective potential was evident. In saliva, untreated, as well as sealed teeth, showed a modest leakage that was less than 20 g. When Tetric Flow was used (negative control) leakage was reduced to a minimum of 2.4 g (s.d. 1.0) in saliva and 12.8 g (s.d. 19.6) in lactic acid. These results were confirmed by SEM analysis. SIGNIFICANCE: The method of liquid scintillation was revealed to be of considerable value in evaluating leakage and acid resistance of potential smooth enamel sealing options. Sealing with an unfilled resin still demonstrated remarkable levels of acid dissolution, although a protection tendency could be observed. This leads to the conclusion that there is a need for further investigation to establish more acid-resistant enamel sealing agents.

Acrylates↗
PubMed1997

Effect of acidic conditioners on dentin morphology, molecular composition and collagen conformation in situ.

OBJECTIVE: The aim of the study was to evaluate the effect of some acidic conditioners on dentin morphology, molecular composition and collagen conformation in situ. METHODS: Smear layer-covered dentin specimens prepared from third molars immediately after extraction were imaged by tapping made AFM and analyzed by MIR-FTIR spectroscopy. The same specimens were subjected to conditioning treatments with CA Agent (Kuraray), Scotchbond Etchant (3M Dental Products) and Scotchbond MP Etchant (3M Dental Products) gels and then imaged and analyzed again. The extent of dentin decalcification at the uppermost 2 microns region was calculated from the percentage reduction in the-PO4/amide I peak area ratio of conditioned specimens relative to their individual smear layer-covered references. These results were compared by ANOVA and Scheffé statistical analyses. The conformational changes of dentin type I collagen at the region were studied qualitatively by deconvoluting the amide I bands of MIR-FTIR spectra and assigning the band components to carbonyl hydrogen bonding states related to the alpha-helix structure. RESULTS: All the conditioners removed the smear layer, funneled the tubules, increased the intertubular roughness and contaminated the dentin surfaces with residues from irreversibly adsorbed thickening agents. Conditioned dentin surfaces showed a reduction in orthophosphates and carbonates and an increase in amide I, II and III groups. CA Agent manifested a significantly lower extent of dentin decalcification than Scotchbond etchants (p < 0.05). Collagen conformational changes involved a decrease in intermolecular hydrogen bonded amide I carbonyls associated with the alpha-helix structure and enhancement of imide carbonyls hydrogen bonded to water, which suggest collagen denaturation. SIGNIFICANCE: Apart from dentin decalcification, the acidic conditioners induced considerable changes on dentin collagen conformation mostly associated with denaturation processes. In addition, irreversibly adsorbed residual thickeners substantially modified the morphology and composition of dentin surfaces. These findings show the complex interaction pathways between conditioners and dentin surfaces and the great potential of modern in situ imaging and analysis techniques in probing these interactions.

Acid Etching, Dental↗
PubMed2000

Enamel demineralisation assessed by computerised image analysis of clinical photographs.

OBJECTIVES: To investigate the use of computerised image analysis to measure the area of demineralisation on the buccal surface of a tooth and to analyse the effect on that measurement of varying the angle at which a photographic image of the buccal surface of a tooth is taken. METHODS: Twenty-two teeth with areas of incremental demineralisation on the buccal surface were photographed perpendicular to the buccal surface and at angles of 20 and 40 degrees, above (Cuspal) and below (Gingival) the perpendicular. The images were captured and analysed using computerised image analysis. RESULTS: The Gingival views showed lower limits of agreement than the Cuspal views, probably due to the positioning of the masking on the lower part of the flash, to reduce reflection. There was a significant difference between the areas of demineralisation measured for the three angles from the Gingival views (p<0.001). The mean differences in areas measured were not linear, but there was a significantly greater reduction in area measured for the 40 degrees views. CONCLUSIONS: Computerised image analysis to measure areas of demineralisation from a captured 35mm slide is reproducible. The position of the masking on the camera flash and the angle of the camera makes a difference to the area measured and the grey scales recorded. Images taken at a larger angle than 20 degrees to the perpendicular will record a significantly reduced area of demineralisation. Standardisation of photographs with the use of calibration markers and manipulation of images is discussed.

Analysis of Variance↗
PubMed2001

Dental caries-protective agents in milk and milk products: investigations in vitro.

OBJECTIVES: To characterise and identify the anti-dental caries components that exist in milk and milk products. METHODS: Standard enamel or hydroxyapatite demineralisation tests were devised to simulate the action of acid on tooth mineral, and they were used to show which constituents of milk possessed a potential protective action against acid attack. RESULTS: Milk and milk products were fractionated and tested, revealing that minerals, including calcium and phosphorus, played a part in this protective process. The findings also drew attention to the effectiveness of minor milk protein or protein-associated components, the structures of which are mostly known, which were separated and characterised by gel electrophoresis as proteose-peptone fractions 3 and 5. The strength of adsorption of the protein or polypeptides in these fractions to dental enamel was measured and found to be sufficient to reduce the extent of demineralisation of enamel by acid buffer solutions. CONCLUSIONS: The removal of lactose, fat, casein and other proteins had little influence on the protective effect of the milk fractions. Besides calcium and phosphorus, milk contains other more powerful protective factors, which were identified as proteose-peptone fractions 3 and 5. Details of their composition and the strength of their adherence to the surface of dental mineral are given.

Animals↗
PubMed2001

The effect of fluoridated and non-fluoridated rewetting agents on in vitro recurrent caries.

OBJECTIVE: This study examined the in vitro caries inhibiting potential of fluoridated and non-fluoridated rewetting agents that are applied to acid-etched enamel and dentine before the use of a water-free, dentine adhesive. MATERIALS AND METHODS: Twelve caries-free premolars were divided into three groups of four teeth each. 2 x 3 x 1.5 mm cavities were prepared on the mesial and distal surfaces of each tooth, with half of the cavosurface margin in enamel and half in root dentine. In Group I (control), One-Step (Bisco, Schaumburg, USA) was applied without etching or rewetting agents. In Group II, cavities were acid-etched, rinsed, dried, and rewetted with Aqua-Prep (Bisco), a non-fluoridated rewetting agent, and then bonded with One-Step. Treatment for Group III was similar to Group II, except that Aqua-Prep F (Bisco), a fluoridated rewetting agent was used. Bonded cavities were restored with a non-fluoride-containing flowable composite (AEliteFlo, Bisco). Artificial carious lesions were induced in these specimens, from which multiple 100+/-20 microm thick longitudinal sections were prepared, yielding 16 specimens per group for evaluation with polarised light microscopy (PLM) and microradiography (MRG). Representative sections were processed for transmission electron microscopy (TEM) examination and scanning transmission electron microscopy/energy dispersive X-ray (STEM/EDX) analyses. RESULTS: The differences in demineralisation of dentine among the groups were not statistically significant for 'relative' lesion depth (p > 0.05, ANOVA, Student-Neuman-Keuls test), but highly significant for 'relative' lesion area (p < 0.001). Wall lesions were consistently present in Group I, while inhibition zones were invariably observed in Group III. 87.5% of Group II specimens exhibited neither wall lesion nor inhibition zone. TEM showed that remnant dentine apatite crystallites within the inhibition zones in Group III were larger and denser than those present within the corresponding wall lesions. STEM/EDX analyses confirmed the presence of calcium, phosphorus and fluorine in these plate-like crystallites. CONCLUSION: When used with a water-free, single-bottle dentine adhesive, a non-fluoridated rewetting agent is able to reduce, but cannot completely prevent recurrent caries. The use of a fluoridated rewetting agent is useful under the situation when microleakage occurs, by providing the additional benefit of fluoride-induced demineralisation inhibition.

Analysis of Variance↗
PubMed2002

Reaction of sound and demineralised dentine to Carisolv in vivo and in vitro.

OBJECTIVES: The aim of the present study was to assess the structural reaction of intact dentine to Carisolv in vivo and in vitro. METHODS: For the in vivo study occlusal cavities were prepared in 48 caries-free molars in Wistar rats (age: three months) and Carisolv-solution was placed into the cavities of 24 M for 1, 10 and 20 min. Twenty four contralateral molars served as controls and were treated with an inert liquid containing purified water, carmellose and erythrosin for corresponding periods. For the in vitro study 24 rat molars were resected en bloc and fractured to expose an area of crown dentine area. Molars were demineralised with EDTA for eight weeks to expose the collagenous dentinal matrix. One half of the specimens was then coated with Carisolv-solution for 20 min. The other half served as a control and was coated with an inert solution for 20 min. RESULTS: In the in vivo specimens no signs of pulp cell damage were observed in the experimental group. The odontoblastic processes were destroyed in proximity to the floor of the cavity but were intact in the inner portion of dentinal tubules in experimental molars and a mechanical damage was noted in the control molars. In the in vitro specimens no structural discrepancy was detected between the experimental molars and the control molars in collagen fibrils of demineralised dentine. CONCLUSIONS: Carisolv causes destruction of cellular components of odontoblastic processes but does not attack healthy collagen fibrils.

Animals↗
PubMed2004

Effect of Er:YAG laser and organic matrix on porosity changes in human enamel.

OBJECTIVES: Cariostatic effects of lasers have been well documented in the past few decades; however, the mechanisms remain unclear. Our previous study revealed the statistically significant effect of organic matrix (OM) in the laser-induced caries prevention. The aim of the present study is to further investigate the role of organic matters in the laser-induced porosity changes. METHODS: Enamel powder from five sound molars was randomly divided into two samples. One sample was treated with approximately 10% NaClO solution to remove OM and the other was left untreated. Both groups were then subjected to irradiation by an Er:YAG laser. The samples were characterized by thermogravimetric analysis (TGA) and N(2) physico-adsorption. RESULTS: TGA results confirmed that the NaClO treatment had at least partially removed the OM in enamel powder. The surface area and pore volume of normal enamel powder decreased significantly after laser treatment. In contrast, in the NaClO-treated enamel powder, laser treatment did not significantly decrease the surface area and the pore volume remained almost unchanged. The substantial difference between the normal enamel powder and the NaClO-treated enamel powder after laser treatment confirmed the laser-induced blocking of OM in the micro-diffusion pathway in enamel. CONCLUSION: The findings in this study seemed to substantiate the "organic blocking theory" as one of the mechanisms in the laser-induced caries prevention.

Dental Enamel↗
PubMed1998

Morphometric assessment of enamel demineralisation from photographs.

OBJECTIVES: To investigate the validity and reproducibility of a method of morphometric assessment of enamel demineralisation. METHODS: An in vitro investigation was carried out on 22 human teeth. One investigator coated the crowns of the teeth with an acid-resistant varnish, leaving a small window on the buccal surface. This was incrementally occluded by varnish over a 14-day period, during which the teeth were placed in a demineralising gel at pH 4.5. After varnish removal, a second investigator blindly quantitated the demineralised area by three methods of examination; direct visual, microscopic and from photographs. The microscopic and photographic measurements were carried out using a morphometric assessment with a 121-dot array. Photographs and assessments were repeated after 1 week. The readings were analysed using the kappa statistic, the limits of agreement and the coefficient of repeatability. RESULTS: Photographic assessments demonstrated excellent agreement for grid positioning (kappa > 0.81) and substantial agreement for reading reproducibility (kappa = 0.61-0.80). The coefficients of repeatability were found to be the same for repeat readings of the same slide and the repeated slides (5.0 mm2). They were higher for the microscopic technique (6.8 mm2) and for the direct visual technique (7.8 mm2). The limits of agreement are presented graphically. CONCLUSIONS: The photographic technique used was a reproducible method of measuring artificial enamel demineralisation. Measurement from photographs was more reproducible than direct measurement with the naked eye. Subjectiveness of the index leads to most variation and more objective means of assessing enamel demineralisation need to be found.

Humans↗
PubMedDate not supplied

Detection of Streptococcus mutans by PCR amplification of the spaP gene in teeth rendered caries free.

OBJECTIVES: To investigate the degree of association between tactile and optical criteria as used to assess the carious status of the enamel-dentine junction (EDJ) during cavity preparation, assessment with a caries detector dye and detection of Streptococcus mutans using culture and polymerase chain reaction (PCR) techniques. METHODS: Twenty-nine teeth, extracted within the previous 30 min, and 15 teeth prepared under rubber dam in vivo, were clinically assessed at the EDJ after the removal of evident carious tissue. Demineralisation was then assessed using a caries detector dye (1% acid red in propylene glycol; Cavex). A rosehead bur was used to remove tissue at the EDJ for culture and PCR analysis. Culture was carried out on a tryptone yeast cystine sucrose bacitracin selective medium, and PCR used to amplify a sequence (192 bp) of the spaP gene, which encodes the surface protein antigen I/II of S. mutans. RESULTS: Demineralised tissue at the EDJ, as shown using the dye, was found in 52% of teeth. Removed tissue was culture and PCR positive for S. mutans in 2 and 47% of teeth, respectively. A highly significant association (77% of cases; P < 0.001) was shown between dye and PCR assessment methods. No association was found between any other combination of assessment methods. CONCLUSIONS: Culture methods may underestimate the presence of S. mutans. Removal of sufficient dye-stained tissue is therefore recommended to prevent further carious assault from residual S. mutans.

Antigens, Bacterial↗
PubMedDate not supplied

Fluoride release and cariostatic ability of a compomer and a resin-modified glass ionomer cement used for orthodontic bonding.

OBJECTIVES: The aims of this study were to compare the local and systemic uptake of fluoride released from a compomer material (Dyract Ortho) and a resin-modified glass ionomer cement (Vitremer) with that of a conventional resin adhesive (Right-On) and to compare the cariostatic ability of each of the test materials with that of the resin control. METHODS: Twenty six patients were randomly allocated to have a bracket bonded to a premolar on one side of the arch with one of the test materials and on the opposite side with the control material. Premolars destined for extraction as part of an orthodontic treatment plan were selected for bonding. A non-fluoride toothpaste was used by all participants for 4 weeks prior to bracket bonding and throughout the 4 week trial period. Fluoride release was measured in saliva, plaque and urine samples taken pre-bonding and 4 weeks post-bonding. Enamel demineralisation was assessed by scoring the buccal surface of each extracted tooth using a caries index. RESULTS: Neither Vitremer nor Dyract Ortho altered salivary or urinary fluoride concentration significantly 4 weeks post-bonding but plaque fluoride concentration increased significantly around premolars bonded with Vitremer. The test materials as a combined group were associated with significantly less demineralisation than the control material but there was no significant difference in cariostatic ability detected between either Dyract Ortho or Vitremer when each group was compared separately with the control. CONCLUSIONS: Fluoride released from Dyract Ortho or Vitremer is likely to exert a local and not a systemic effect. In a 4-week clinical study, the cariostatic ability of the fluoride-releasing cements, as a combined group, was superior to that of the non-fluoride releasing control but there was no significant difference in cariostatic ability between the two test materials when each test group was compared separately with the control.

Adolescent↗
PubMed2003

Bond failure and decalcification: A comparison of a cyanoacrylate and a composite resin bonding system in vivo.

This prospective, in vivo study compared bond failure and enamel decalcification with a cyanoacrylate bracket bonding system (SmartBond, Gestenco International, Gothenburg, Sweden) and a traditional light-cured composite system (Light Bond, Reliance Orthodontic Products, Itasca, Ill). A total of 327 teeth were evaluated after a period of 12 to 14 months; 163 experimental teeth were bonded with the cyanoacrylate bonding system, and 164 control teeth were bonded with the light-cured composite resin. All teeth were evaluated for breakage (bond failure). The average percentage of bracket failures with cyanoacrylate was 55.6% compared with 11.3% with composite resin (P <.001). All maxillary anterior teeth (94) were evaluated for enamel decalcification on a graded scale. Occurrence of enamel decalcification between the 2 bonding systems after 1 year of orthodontic treatment was similar. The cyanoacrylate bonding material had more than 4 times as many bond failures and a similar amount of decalcification as the traditional composite material. Cyanoacrylate as a routine orthodontic bonding agent is not a suitable bonding material for clinical practice at this time. It is important to test new bonding systems in vivo in several studies before using them in routine clinical practice.

Adolescent↗
PubMed1994

Effect of rotary electric toothbrush versus manual toothbrush on decalcification during orthodontic treatment.

The purpose of this study was to determine whether daily use of a rotary electric toothbrush (Rota-dent, Prodentec Corp., Batesville, Ark.) and a 0.05% sodium fluoride (NaF) rinse would significantly reduce decalcification when compared with manual toothbrushing only (control group) or manual toothbrushing and daily use of a NaF rinse (rinse group). All three groups used a standard fluoride toothpaste. Ninety consecutive adolescent patients who were to receive orthodontic treatment were placed into one of three groups according to age and sex criteria. Decalcification was evaluated single blind by two calibrated examiners on the facial surfaces of all permanent teeth before appliances were placed (baseline) and 3 months after appliances were removed (posttreatment). Data were analyzed by analysis of covariance with the dependent variable derived by subtracting the baseline decalcification scores from the posttreatment scores and using the baseline scores as the covariate. The results showed that although there were no significant differences between the three groups at baseline, the Rota-dent group showed significantly (p < 0.05) less posttreatment decalcification than either the control or rinse groups. In a separate analysis of first molars, the Rota-dent group again showed the least decalcification and the control group showed the most. These data suggest that twice daily use of the Rota-dent electric toothbrush with a standard fluoride toothpaste and once daily use of a 0.05% NaF rinse is more effective for preventing decalcification in adolescents during orthodontic treatment with fixed appliances than either conventional toothbrushing with a fluoride toothpaste, or similar toothbrushing and toothpaste with a once daily NaF rinse.

Adolescent↗