Gender and race distribution of dental graduates (1985 - 2004) and first year dental students (2000 - 2005) in South Africa

This paper, written at the close of a decade of democracy in South Africa, sets out to analyse the demographic profile of dental graduates from 1985-2004 at the five Faculties/Schools of Dentistry in South Africa. A comparison of the profiles for the pre-democracy (1985-1994) and post-apartheid (1995-2004) periods has been made. The demographic profile of first year dental students from 2000-2005 is also presented. From 1985-1994, most dental graduates were male (79%), but this changed substantially from 1995-2004, with females comprising 46% of those graduating. In the pre-democracy period, more than three-quarters of all graduates were White (78%), decreasing to 46% in the post-apartheid period under review. Black graduates increased from 6% to 24% across the two study periods. Amongst the first year dental student intake from 2000- 2005, females comprised 57%. There was an almost equal distribution across the White, Black and Asian groups. Dental faculties/schools have made important strides in transforming the demographic profile of their students. The percentage of Black graduates, however, needs to be significantly increased if it is to reflect the national population. Faculties/schools must further ensure that able students from working class background are identified and considered for acceptance into the undergraduate dental programme, and should then be offered the necessary academic and mentoring support to enable success

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 View the MathML source was ∼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 ∼50% after 14 months and the a* value with ∼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.Web of Scienc

In vivo Spectrophotometric Assessment of the Tooth Whitening Effectiveness of Nite White 10% with Amorphous Calcium Phosphate, Potassium Nitrate and Fluoride, Over a 6-month Period

To clinically evaluate the effectiveness of Nite White 10% carbamide peroxide with amorphous calcium phosphate, potassium nitrate and fluoride over a 6-month follow-up period. Nite White was applied nightly for 14 days, according to the manufacturer’s instructions. The color of teeth 11 and 21 of twenty one subjects was measured with a spectrophotometer (L*; a*; b*). Subjects were instructed to take note of any tooth sensitivity and gingival irritation. For all three components (L*, a* and b*) statistical significant differences (p<0.05) in the values between base-line (pre-bleaching) and; after treatment, after 1-month, after 3-months as well as after 6-months were found (Wilcoxon Signed Rank Sum Test). Significant differences were also found amongst the ΔE*ab (0-14days) values and; ΔE*ab (0-1 month), ΔE*ab (0-3 months) and ΔE*ab (0-6 months). However, no significant differences were found between pairs of ΔE*ab (0-1 month), ΔE*ab (0-3 months) and ΔE*ab (0-6months). The decrease in ΔE*ab was the highest after 1 month (~30%). The highest decrease in L* was about 58% after 1 month. Over the 14-day treatment period tooth sensitivity was 24.5%. Conclusions: Nite White ACP demonstrated significant tooth-whitening (unit increase = 5.29) with a low tooth sensitivity (25%) probably due to the presence of amorphous calcium phosphate, potassium nitrate, and fluoride. The whitening effect decreased the most after one month and then maintained well even after a 6 month period (units 3.89)

Effect of various tooth-whitening products on enamel microhardness

Objectives: The purpose was to evaluate the effect of various tooth-whitening products on the South African market, 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) was enamel blocks (n=10) kept in artificial saliva at 37˚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˚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. 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 damaged enamel except Opalescence® Boost 38% HP. In general, the products containing carbamide peroxide were more damaging while longer treatment periods influenced the microhardness values negatively. Nite White® ACP without fluoride showed relatively more damage than all the other products containing fluoride.Department of HE and Training approved lis

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.Department of HE and Training approved lis

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.Department of HE and Training approved lis

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).Department of HE and Training approved lis