Guidance for the gastrointestinal evaluation and management of iron deficiency in Sub-Saharan Africa.

BACKGROUND: Over 30% of the world's population is anaemic, with a significant proportion of these being iron deficient. As iron deficiency (ID) anaemia in men and post-menopausal women is mostly caused by gastrointestinal blood loss or malabsorption, the initial evaluation of a patient with ID anaemia involves referral to a gastroenterologist. The current drive towards patient blood management in sub-Saharan Africa (SSA)prescribes that we regulate not only the use of blood transfusion but also the management of patients in whom the cause of iron loss or inadequate iron absorption is sought. Recommendations have been developed to: (i) aid clinicians in the evaluation of suspected gastrointestinal iron loss and iron malabsorption, and often a combination of these; (ii) improve clinical outcomes for patients with gastrointestinal causes of ID; (iii) provide current, evidence-based, context-specific recommendations for use in the management of ID; and (iv) conserve resources by ensuring rational utilisation of blood and blood products. METHOD: Development of the guidance document was facilitated by the Gastroenterology Foundation of Sub-Saharan Africa and the South African Gastroenterology Society. The consensus recommendations are based on a rigorous process involving 21 experts in gastroenterology and haematology in SSA. Following discussion of the scope and purpose of the guidance document among the experts, an initial review of the literature and existing guidelines was undertaken. Thereafter, draft recommendation statements were produced to fulfil the outlined purpose of the guidance document. These were reviewed in a round-table discussion and were subjected to two rounds of anonymised consensus voting by the full committee in an electronic Delphi exercise during 2022 using the online platform, Research Electronic Data Capture. Recommendations were modified by considering feedback from the previous round, and those reaching a consensus of over 80% were incorporated into the final document. Finally, 44 statements in the document were read and approved by all members of the working group. CONCLUSION: The recommendations incorporate six areas, namely: general recommendations and practice, Helicobacter pylori, coeliac disease, suspected small bowel bleeding, inflammatory bowel disease, and preoperative care. Implementation of the recommendations is aimed at various levels from individual practitioners to healthcare institutions, departments and regional, district, provincial and national platforms. It is intended that the recommendations spur the development of centre-specific guidelines and that they are integrated with the relevant patient blood management protocols. Integration of the recommendations is intended to promote optimal evaluation and management of patients with ID, regardless of the presence of anaemia.

The effect of three whitening oral rinses on enamel micro-hardness.

The purpose of this study was to determine the effect on human enamel micro-hardness of three over-the-counter whitening oral rinses available in South Africa. Enamel fragments were gathered into three groups of 15 each. One group was exposed to Colgate Plax Whitening Blancheur, the second group to White Glo 2 in 1 and the third to Plus White, in each case for periods recommended by the respective manufacturers. Surface micro-hardness of all groups was measured before and after a 14 day treatment period. pH levels of the oral rinses were also determined with a combination pH electrode. Pre- and post- treatment data were analysed by the Wilcoxon Signed Rank Sum Test. According to the micro-hardness values no significant (p > 0.05) enamel damage was found as a result of treatment. However, it was observed that Colgate Pax and White Glo decreased the enamel hardness, an early sign of enamel damage, while Plus White showed a small increase in hardness. The three whitening oral rinses on the South African market do not damage the tooth enamel significantly when used as recommended by the manufacturers. However, extending the contact period and increasing the frequency of application might lead to damage of enamel.

Guidelines for the selection of tooth whitening products amongst those available on the market.

BACKGROUND: Several tooth whiteners are available on the market, and the ideal choice should be determined by efficacy and optimal clinical results. OBJECTIVES: The purpose of this study was to compare the reported clinical success rates of different tooth whitening products. SEARCH STRATEGY: The relevant literature (1998 - 2011) was studied, using as sources the databases: Google Scholar, Science Direct, Medline and Pubmed. SELECTION CRITERIA: The material was clearly identified, the manufacturers' instructions were respected and the sample size stated. RESULTS AND CONCLUSIONS: This descriptive report on 49 papers focuses on the total colour change, measured with a calibrated shade guide and also numerically (colourimeter, chromameter or spectrophotometer), the relapse of the colour change and tooth sensitivity. In general, the dentist-supervised at-home bleaching and the in-office treatment gave approximately the same initial percentage improvement of tooth whitening. However, the relapse after a four week or longer period was significantly higher for the in-office treatment. The treatment of choice should be a dentist supervised at-home bleaching product which generally contains approximately 10% carbamide peroxide applied over about 14 days for about eight hours per night. Tooth sensitivity should not be a general problem although some subjects might choose to discontinue treatment as a result of sensitivity.

Whitening efficacy of three over-the-counter oral rinses.

AIM: The aim of the study was to determine the whitening efficacy of three different oral rinses. MATERIALS AND METHODS: Eighty extracted teeth were randomly divided into four groups, cleaned with a slow-speed handpiece with pumice and placed in a staining broth for 14 days. Measurements of tooth shades were measured with a spectrophotometer. Three groups (20 each) were then exposed to Colgate Plax Whitening Blancheur (A), White Glo 2 in 1 (B) and Plus White (C) for 21 days for 2 minutes a day and in between stored in artificial saliva. The other group acted as a control and was only stored in the artificial saliva. RESULTS: The Kruskal-Wallis and Tukey-Kramer analysis showed no statistical significant differences (on a 5% basis) for the differences between base-line and after treatment (21 days) for deltaL*, deltaa*, deltab* and deltaE*ab median values amongst the control, Colgate Plax Whitening Blancheur, White Glo 2 in 1, and Plus White. CONCLUSION: None of the 3 commercially available oral rinses resulted in any significant bleaching effect on the teeth over a 21 day treatment period.

A clinical study of the effectiveness of two different 10% carbamide peroxide bleaching products: a 6-month followup.

The purpose of this study was to evaluate the efficacy of two different 10% carbamide peroxide bleaching products just after treatment and after a 6-month follow-up period. Methods. Two 10% carbamide peroxide products (Opalescence PF and Nite White ACP) were applied nightly for 14 days, according to the manufacturers' instructions. The color of teeth 11 and 21 of thirty-four subjects having A2 or darker teeth were measured with a spectrophotometer (L(∗); a(∗); b(∗)) before treatment, just after treatment (14 days) and after 6 months. Results and Conclusions. Both products produced significant whitening of teeth with total color change (ΔE(ab) (∗)) of approximately 5.20 units. There was a significant improvement in all 3 color coordinates (L*, a*, and b(∗)) for up to 6 months postbleaching (P < .05). Nite White showed a higher degree of relapse (27%) than Opalescence (18%) over the 6-month period. It is suggested that rebleaching after 6 months is not necessary.

Effect of four over-the-counter tooth-whitening products on enamel microhardness.

OBJECTIVES: This in vitro study evaluated the effect of four over-the-counter tooth-whitening products on enamel microhardness. METHODS: Fifty enamel blocks were prepared from extracted human molar teeth. The enamel surfaces were polished up to 1200 grit fineness and the specimens randomly divided into five groups. Enamel blocks were exposed to: Rapid White (n=10); Absolute White (n=10); Speed White (n=10) and White Glo (n=10) whitening products, according to the manufacturers' instructions. As control, ten enamel blocks were kept in artificial saliva at 37 degrees C without any treatment. Microhardness values were obtained before exposure (baseline) and after 1, 7 and 14-day treatment periods using a digital hardness tester with a Vickers diamond indenter. Data were analysed using Wilcoxon Signed Rank Sum Test, one-way ANOVA and Tukey-Kramer Multiple Comparison Test (p<0.05). RESULTS: Both Rapid White and Absolute White reduced enamel microhardness. Speed White increased the microhardness of enamel, while White Glo and artificial saliva had no effect on hardness. CONCLUSIONS: Over-the-counter tooth-whitening products might decrease enamel microhardness depending on the type of product.

The pH of various tooth-whitening products on the South African market.

OBJECTIVES: The purpose of this in vitro study was to investigate the pH of 21 commercially available tooth-whitening products. METHODS: Tooth-whitening products were divided into four categories: dentist supervised-home bleaching products (n = 5); in-office bleaching products (n = 5); over-the-counter bleaching products (n = 4) and whitening toothpastes and rinses (n = 7). The pH of three samples of each product was measured using an Orion Expandable Ion Analyzer EA940 with a Sure-Flow, Epoxy-body combination pH electrode. The group data were analysed using one way ANOVA (significant at p < 0.05). RESULTS: The five dentist supervised-home bleaching products had a mean pH of 6.21 +/- 0.76 and ranged from 4.88 to 6.81. The five in-office bleaching products had a mean pH of 6.26 +/- 1.19 and ranged from 5.30 to 7.85. The four over-the-counter whitening products had a mean pH of 5.07 +/- 1.74 and ranged from 3.76 to 8.03 and the seven whitening toothpastes had a mean pH of 7.66 +/- 1.19 and ranged from 6.61 to 9.68. The pH of the over-the-counter category was significantly lower (more acidic) than all other categories (p < 0.05). The whitening gel of Rapid-White had the lowest acidic pH of 3.76 and Colgate Advanced Whitening toothpaste showed the highest alkaline pH of 9.68. CONCLUSIONS: The pH of all tooth-whitening products showed a wide range from 3.76 (highly acidic) to 9.68 (highly alkaline). Over-the-counter whitening products showed the lowest pH levels and in general these can be expected to damage enamel more than the other products. Dentists should be vigilant with regards to products used outside their surgeries and should warn their patients accordingly. CLINICAL IMPLICATIONS: The acidic pH of many of the whitening products other than in-office bleaching products is of concern and the general public should be better informed by the dental professionals of the dangers of these products.

Spectrophotometric assessment of the effectiveness of Opalescence PF 10%: a 14-month clinical study.

OBJECTIVES: To evaluate the effectiveness of Opalescence PF 10% just after treatment, at 6-month follow-up and at a 14-month follow-up period. METHODS: Opalescence PF 10% was applied nightly for 14 days. The color of teeth 11 and 21 of 17 subjects were measured with a spectrophotometer (L*; a*; b*) before treatment, just after treatment (14 days), after 6 months and after 14 months. Subjects were instructed to take note of any tooth sensitivity. RESULTS: For all three components (L*, a* and b*) statistical significant differences (p<0.05) in the values between base-line, after treatment (14 days later), after 6 months and after 14 months were found (Wilcoxon Signed Rank Sum Test). The decrease in L* was about 20% after 6 months and about 50% after 14 months. The a* value decreased approximately 14% after 6 months but was worse after 14 months than at the beginning. The b* value decreased the least with about 9% after 6 months and about 8% after 14 months. The decrease in DeltaE(ab)(*) was approximately 20% after 14 months. Less than 20% of the subjects experienced mild tooth sensitivity just after treatment. CONCLUSION: Significantly whiter teeth were found after treatment as well as after a 6-month follow-up period. The whiteness/brightness (L*) decreased with approximately 50% after 14 months and the a* value with approximately 50% after 7 months, while the yellowness (b* value) remained even after 14 months. CLINICAL IMPLICATIONS: The product is an effective tooth whitener resulting in only low tooth sensitivity. Re-bleaching could be done at about 14 months.

The relationships between two different drinking water fluoride levels, dental fluorosis and bone mineral density of children.

This field study included the whole population of children aged 10-15 years (77 from a 0.19 mg/L F area; 89 from a 3.00 mg/L F area), with similar nutritional, dietary habits and similar ethnic and socioeconomic status. The fluoride concentration in the drinking water, the bone mineral content, the bone density and the degree of dental fluorosis were determined. The left radius was measured for bone width, bone mineral content, and bone mineral density. The mean fluorosis score was 1.3 in the low fluoride area and 3,6 in the high fluoride area. More than half the children in the low fluoride area had no fluorosis (scores 0 and 1) while only 5% in the high fluoride area had none. Severe fluorosis (30%) was only observed in the high fluoride area. The Wilcoxon Rank Sum Test indicated that fluorosis levels differed significantly (p < 0.05) between the two areas. No relationships were found between dental fluorosis and bone width or between fluorosis and bone mineral density in the two areas (Spearment Rank correlations). A significant increase in bone width was found with age but no differences amongst and boys and girls. A significant positive correlation was found in the high fluoride area between bone mineral density over age. In the 12-13 and 13-14 year age groups in the high fluoride area, girls had higher bone mineral densities. However, a significant negative correlation (p<0.02) was found for the low fluoride area (0.19 mg/L F) over age.

Effect of various tooth-whitening products on enamel microhardness.

OBJECTIVES: The purpose of this in vitro study was to evaluate the effect of various tooth-whitening products containing carbamide peroxide (CP) or hydrogen peroxide (HP), on enamel microhardness. METHODS: Enamel blocks were exposed to: Nite White ACP 10% CP (Group 2, n=10); Yotuel Patient 10% CP (Group 3, n=10); Opalescence PF 10% CP (Group 4, n=10); Opalescence PF 20% CP (Group 5, n=10); Opalescence Treswhite Supreme 10% HP (Group 6, n=10); Yotuel 10 Minutes 30% CP (Group 7, n=10); Opalescence Quick 45% CP (Group 8, n=10), Yotuel Special 35% HP (Group 9, n=10), Opalescence Boost 38% HP (Group 10, n=10) according to the instructions of the manufacturers. The control (Group 1, n=10) was enamel blocks kept in artificial saliva at 37 degrees C without any treatment. The microhardness values were obtained before exposure and after a 14-day treatment period. Specimens were kept in artificial saliva at 37 degrees C between treatments. Data were analysed using Kruskal-Wallis one-way ANOVA and Tukey-Kramer Multiple Comparison Test. Indent marks on the enamel blocks were also examined under the Scanning Electron Microscope. RESULTS: All whitening products decreased enamel microhardness except group 10 but only Groups 2, 3, 4, 5 and 7 showed significant decrease in enamel microhardness as compared to the control group (p < 0.05). Groups 2, 3 and 7 differed significantly from all the other groups (p < 0.05). The highest damage was recorded for Group 2 (Nite White ACP 10% CP), which differed significantly from Groups 3 and 7. SEM images also showed damage to enamel. CONCLUSIONS: All products tested in this study decreased enamel microhardness except Opalescence Boost 38% HP. The products containing carbamide peroxide were more damaging to enamel because of the longer application times. Nite White ACP 10% CP showed the highest reduction in enamel microhardness as compared to other products tested.

Effect of four different opalescence tooth-whitening products on enamel microhardness.

OBJECTIVES: The purpose was to evaluate the effect of various Opalescence tooth-whitening products on enamel. METHODS AND MATERIALS: Enamel blocks were exposed to Opalescence PF 10% Carbamide Peroxide (n = 10), Opalescence PF 20% Carbamide Peroxide (n = 10), Opalescence Trèswhite Supreme 10% Hydrogen Peroxide (n = 10) and Opalescence Quick PF 45% Carbamide Peroxide (n = 10) according to the manufacturer's instructions. The control group was enamel blocks (n = 10) kept in artificial saliva. The values were obtained before exposure and after the 14-days treatment period. Enamel blocks were kept in saliva between treatments. Indent marks on enamel blocks were examined using the scanning electron microscope for treatment effects. RESULTS: All four different Opalescence products damaged enamel. The most damage was done when treated for a long period (112 hours). SEM images also showed damage to enamel by all 4 products. Opalescence with 10% and with 20% Carbamide Peroxide showed the highest damage, which also differed significantly (p < 0.05) from the saliva control group (p < 0.05; Tukey-Kramer Multiple comparison test). CONCLUSION: All 4 Opalescence products damaged enamel. Higher damage was done by the 10% carbamide peroxide and 20% carbamide peroxide products because of the much longer exposure period (112 hours in comparison to 7 hours).

A comparison of microleakages of five different recent bonding agents/systems in enamel and dentine.

UNLABELLED: This study compared the microleakages in enamel and dentine of newly developed bonding systems from different manufacturers. Fifteen or more extracted non-carious human premolars were used for each dental material system. The bonding systems were used with their respective composites. Cylindrical cavities were prepared in enamel (scored as a separate entity 0-3) and cementum/dentine (scored 0-4) on the buccal surface at the cemento-enamel junction and restored. The specimens were thermocycled, cut into slices and the depth of dye penetration scored. For enamel, the microleakage values of Clearfil Protect Bond (CPB; median = 1.0) and Xeno III (2.3) did not differ statistically (p > 0.05, Chi-square test), while the microleakage of CPB (1.0) was significantly better than that of GC Unifil Bond (GC; 3.0), Prime & Bond XP (P & B; 3.0) and Adper Prompt L-Pop (APL; 3.0), p < 0.05. At the cementum/dentine side significantly (p < 0.05) more microleakage for CPB (2.0) was found than for GC (0.0), P&B (0.5), APL (0.5), and Xeno III (0.5). CONCLUSION: Enamel was most effectively sealed by CPB and cementum/dentine by GC, P&B, APL and Xeno III. The chemical composition perse did not seem to determine the amount and location of microleakage.

Patterns of tooth surface loss among winemakers.

There are a few documented case studies on the adverse effect of wine on both dental hard and soft tissues. Professional wine tasting could present some degree of increased risk to dental erosion. Alcoholic beverages with a low pH may cause erosion, particularly if the attack is of long duration, and repeated over time. The purpose of this study was to compare the prevalence and severity of tooth surface loss between winemakers (exposed) and their spouses (non-exposed). Utilising a cross-sectional, comparative study design, a clinical examination was conducted to assess caries status; the presence and severity of tooth surface loss; staining (presence or absence); fluorosis and prosthetic status. The salivary flow rate, buffering capacity and pH were also measured. Thirty-six persons, twenty-one winemakers and fifteen of their spouses participated in the study. It was possible to show that there was a difference in terms of the prevalence and severity of tooth surface loss between the teeth of winemakers and those who are not winemakers. The occurrence of tooth surface loss amongst winemakers was highly likely due to frequent exposure of their teeth to wine. Frequent exposure of the teeth to wine, as occurs among wine tasters, is deleterious to enamel, and constitutes an occupational hazard. Erosion is an occupational risk for wine tasters.

Cytotoxicity of a dentine bonding agent on four different cell-lines.

UNLABELLED: The aim of this study was to compare the cytotoxicity of a recently available dentine bonding agent on four different cell-lines (three human dental pulp fibroblast cell-lines and one mouse 3T3 fibroblast cell-line). METHODOLOGY: Three human dental pulp cell-lines from 3 different donors and one established 3T3 mouse cell-line were grown and sub-cultured. Cell viability following exposure to Scothbond was then compared to a similar number of controls using the MTT assay. RESULTS: Scotchbond 1 was cytotoxic to all four cell-lines. 3T3 cells showed a survival rate of about 60% as compared to two of the human dental pulp cells which showed a significantly lower survival rate (p<0.05, Kruskal-Wallis Multiple-Comparison Test). CONCLUSION: These findings indicated that is cytotoxic to both human pulp and 3T3 cell-lines. In general, the human pulp cell-lines showed higher sensitivity than the 3T3 cell-lines. CLINICAL SIGNIFICANCE: Scotchbond 1 cannot be recommended for direct pulp capping techniques and care should be taken when using this dentine bonding agent in cavities where the remaining dentine layer is minimal.

Effect of saliva contamination on microleakage of a bonding system.

UNLABELLED: Saliva contamination is a major clinical problem during restorative dental treatment. Restorative systems must possess sufficient marginal sealing ability to avoid microleakage. PURPOSE: The purpose of this study was to investigate the effect of saliva contamination on the microleakage of cavities restored with Prime & Bond NT and Dyract-AP. METHOD: Cavities were prepared with occlusal margins in enamel and gingival margins in dentine on the buccal surfaces of extracted human permanent premolar teeth. The cavities were etched with phosphoric acid or a non rinse conditioner (NRC). Preparations were distributed randomly into 4 treatment groups (N = 18) consisting of two respective etching methods (phosphoric acid/NRC), each with and without saliva contamination. After the restorative process the samples were thermocycled in dye, sectioned, and scored for microleakage. RESULTS: Contamination with saliva had no significant effect on microleakage on the enamel or dentine sides where phosphoric acid was used as conditioner. Where NRC was used, significantly more microleakage was observed at the enamel sides, but significantly less at the dentine sides.

Cytotoxicity of two concentrations of a dentine bonding agent on mouse 3T3 and human pulp fibroblast cell-lines.

The objective of this study was to investigate the cytotoxicity and effect of concentration of a recent dentine bonding agent on a mouse fibroblast cell-line (3T3) and four different human pulp fibroblast cell-lines. A mouse fibroblast 3T3 cell-line and 4 different human pulp fibroblast cell lines were used. The cells were grown and subcultured using standard conditions. For the testing of the cytotoxicity of the bonding agent (Prime & Bond NT) it was extracted with DMEM medium and the different cell-lines were exposed to the extraction. The MTT assay was used to establish the number of viable cells. For all 5 pairs (control vs test sample) of cell-lines for 4 microl bonding agent, the mouse and only two of the four human cell-lines showed a statistical significant difference (p < 0.05; Mann-Whitney) due to the cytotoxicity of the bonding agent. However, all 5 pairs showed significant differences (p < 0.05) at the 8 microl concentration level. To investigate the relative effect of concentration (4 microl compared to 8 microl) of a chemical agent (we used a bonding agent, Prime & Bond NT) on the cytotoxicity of these 5 cell-lines, the Kruskal-Wallis Multiple-Comparison test was used on the standardised medians. Statistically significant differences (p < 0.05) were found for various cell-lines between both concentration levels. In general, the tested bonding agent, at a higher concentration level, has an increased cytotoxic effect on all 5 cell-lines. About 69% (median) of 3T3 cells stayed viable with 4 microl (0.94cm2/ml) bonding agent and 61% when 8 microl was used. For the pulp cells the percentages were between 91% and 72% for 4 microl and between 77% and 24% for 8 microl. These findings indicated that the bonding agent Prime and Bond NT was cytotoxic and that different human pulp fibroblast cell-lines should be used in the cytotoxic testing of dental materials and secondly, if only one concentration is to be used it should be in the higher range of that suggested by the ANSI/ADA document (2000, Revision) for recommended standard practices for biological evaluation of dental materials.

Volumetric polymerisation shrinkage of different dental restorative materials.

STATEMENT OF PROBLEM: Polymerisation shrinkage is a critical limitation of dental resins and may contribute to micro leakage. PURPOSE: The purpose of this study is to record and compare volumetric changes of various dental composites and compomers, exposed for 40 seconds to a commercial halogen light source. MATERIAL AND METHODS: Eleven light-polymerised composites and compomers were evaluated using a dilatometer that recorded the polymerisation shrinkage every 0.5 second. The mercury column pressure was measured electronically with a pressure-sensitive transducer, and the data recorded and stored in a computer. The computer also recorded the temperature, controlled the light-source and displayed the data in graphic format. Every material was tested ten times. The data were analysed by means of an ANOVA (P < 0.05). RESULTS: A high rate of shrinkage occurred for all materials in the first ten seconds of polymerisation. Surefil showed the lowest rate while TPH displayed the highest. Of the higher filled materials, Surefil (0.96%) showed the least shrinkage, followed by Z250 (0.99%), Dyract AP (1.18%), Herculite (1.27%), Compoglass (1.32%), Amelogen (1.34%) and TPH-Spectrum (1.6%). Overall, the flowable materials exhibited significantly more shrinkage (P < 0.05). For this group Compoglass Flow (2.3%) showed the least shrinkage followed by Filtec Flow (2.31%). Permaflo (3.6%) exhibited the most shrinkage followed by Dyract Flow (3%). CONCLUSION: Within the limitations of this study, it is concluded that significant differences exist among the polymerisation shrinkage of the most resins tested. An increase in the filler content of a material significantly lessens the polymerisation shrinkage while an increase in the monomer concentration causes significantly more polymerisation shrinkage. CLINICAL SIGNIFICANCE: The more flowable a composite material becomes, the more the restoration will shrink. Clinicians should take this into account when they decide on cavity design and materials to use.

In vitro human dental enamel erosion by three different wine samples.

The aim of this study was to investigate the erosive effect of different wine samples on the enamel of human permanent teeth. Twenty-one extracted, sound, permanent human incisor teeth were imbedded in epoxy resin and seven immersed in each of the three different wine samples for 0, 2, 5, 15, 30, 45 and 60 minute periods. The Knoop hardness for each tooth at each of the immersed periods was determined as a measure of the degree of enamel erosion (demineralisation). The main finding was that all three wines eroded enamel (softer enamel) which should mainly be due to their very low pH values (3.2, 3.7, 3.8) and high total acid content. From the Wilcoxon non-parametric tests it was clear that wine 2 had the severest influence on the hardness of the teeth, and the wines differed significantly (p < 1%) from 30 minutes onwards. These tests showed that wine 1 differed significantly from wine 2 from 30 minutes onwards and so did wine 3, but wines 1 and 3 did not differ at all (p > 5%). It is concluded that all three wine samples were erosive to enamel and it is difficult to predict the relative erosion rate of different kinds of wines according to their chemical compositions, as this process is most probably governed and affected by a large number of a combination of factors. The only reliable way to know the exact degree of erosion of a specific wine is by means of a laboratory study. Possible ways to decrease the damaging effect of erosion caused by wine are provided.

Dentine bonding agents--a review of adhesion to dentine.

Although constant innovation has improved the performance of dentine adhesives, the true mechanism of resin adhesion to dentine is still not clear and the optimal dentinal surface pretreatment has yet to be determined for adhesive integrity of resin to dentine. The integrity of the collagen fibrils left exposed upon acid etching seem to play a major role in the mechanism of adhesion and intermingling of the adhesive monomers with the filigree of collagen fibers or hybrid layer should be considered the paramount dentine bonding mechanism. Definite trends are emerging but more research is necessary before general conclusions can be made about the functions of different bonding agents. The all-in-one self-etching/self-primer bottle systems are relatively new to the market and need more research before they can be advocated as the agent of choice.