Browsing Faculty of Dentistry by Author "Grobler, Sias"
Now showing items 1-12 of 12
-
Basson, Nicolaas; Grobler, Sias (BioMed Central, 2008)[more][less]
Abstract: Background: Honey has been shown to have wound healing properties which can be ascribed to its antimicrobial activity. The antimicrobial activity can be effective against a broad spectrum of bacterial species especially those of medical importance. It has also been shown that there is considerable variation in the antimicrobial potency of different types of honey, which is impossible to predict. With this in mind we tested the antimicrobial activity of honeys produced from plants grown in South Africa for their antibacterial properties on selected standard strains of oral microorganisms. Methods: The honeys used were produced from the blossoms of Eucalyptus cladocalyx (Bluegum) trees, an indigenous South African plant Leucospermum cordifolium (Pincushion), a mixture of wild heather shrubs, mainly Erica species (Fynbos) and a Leptospermum scoparium (Manuka) honey. Only pure honey which had not been heated was used. The honeys were tested for their antimicrobial properties with a broth dilution method. Results: Although the honeys produced some inhibitory effect on the growth of the microorganisms, no exceptionally high activity occurred in the South African honeys. The carbohydrate concentration plays a key role in the antimicrobial activity of the honeys above 25%. However, these honeys do contain other antimicrobial properties that are effective against certain bacterial species at concentrations well below the hypertonic sugar concentration. The yeast C. albicans was more resistant to the honeys than the bacteria. The species S. anginosus and S. oralis were more sensitive to the honeys than the other test bacteria. Conclusion: The honeys produced from indigenous wild flowers from South Africa had no exceptionally high activity that could afford medical grade status. URI: http://hdl.handle.net/10566/597 Files in this item: 1
BassonAntimicrobialactivity2008.pdf (210.5Kb) -
Grobler, Sias; Majeed, Abdul; Hayward, Roche; Rossouw, Roelof; Moola, Mohamad H.; van Wyk Kotze, Theuns (Hindawi Publishing Corporation, 2011)[more][less]
Abstract: 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 andNiteWhite 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 URI: http://hdl.handle.net/10566/587 Files in this item: 1
GroblerClinicalStudy2011.pdf (676.3Kb) -
Olivier, Annette; Grobler, Sias; Osman, Yusuf (Scientific Research Publishing, 2012)[more][less]
Abstract: Today it is generally accepted that most bonding agents are cytotoxic. In this study the relative cyto-toxicity of seven recent dentine bonding agents on mouse 3T3 fibroblast cells were investigated. Materials and Methods. Near-confluent mouse 3T3 fibro- blast cells were exposed to Dulbecco Modified Eagle’s Medium containing extractions from the seven different bonding agents. The cell survival rate was then determined using the standard MTT assay. Results. The cell survival rate ranking is: iBond (94%) < Gbond (78%) < Xeno V (71%) < Adper Easy Bond (63%) < Xeno V+ (61%) < Adper Scotchbond SE (33%) < XP Bond (32%). Part A of Adper Scotchbond SE had a survival rate of 35% and part B 38%. These two parts did not differ significantly. Adper Scotchbond SE and XP Bond do not differ significantly. While Xeno V+, Xeno V and Adper Easy Bond do not differ. (p < 5%; Tukey-Kramer Multiple-Comparison Test). Conclusion. All of the tested adhesive bonding agents were cytotoxic with survival rate of 3T3 cells between 94% to 31%. Of the 7 bonding agents tested iBond was found to be only slightly toxic and by far the least toxic. The two bonding agents (XP Bond and Adper Scotchbond SE) containing UDMA plus TEGDMA plus HEMA plus camphorquinone were found to be the most toxic. URI: http://hdl.handle.net/10566/589 Files in this item: 1
OlivierCytotoxicityofseven2012.pdf (339.1Kb) -
Majeed, Abdul; Grobler, Sias; Moola, Mohamad H.; Rossouw, Roelof; Van Wyk Kotze, Theuns (South African Dental Association, 2008)[more][less]
Abstract: 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). URI: http://hdl.handle.net/10566/581 Files in this item: 1
MajeeddifferentOpalescence2008.pdf (1.805Mb) -
Majeed, Abdul; Grobler, Sias; Moola, Mohamed; Oberholzer, Theuns (South African Dental Association, 2011)[more][less]
Abstract: 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. URI: http://hdl.handle.net/10566/616 Files in this item: 1
-
Grobler, Sias; Majeed, Abdul; Moola, Mohamad H. (South African Dental Association, 2009)[more][less]
Abstract: 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. URI: http://hdl.handle.net/10566/590 Files in this item: 1
GroblerEnamelMicrohardness2009.pdf (1.648Mb) -
Grobler, Sias; Majeed, Abdul; Moola, Mohamad H.; Rossouw, Roelof; van Wyk Kotze, Theuns (Bentham Open, 2011)[more][less]
Abstract: 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 (prebleaching) 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 E*ab (0-14days) values and; E*ab (0-1 month), E*ab (0-3 months) and E*ab (0-6 months). However, no significant differences were found between pairs of E*ab (0-1 month), E*ab (0-3 months) and E*ab (0-6months). The decrease in E*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). URI: http://hdl.handle.net/10566/586 Files in this item: 1
GroblervivoSpectrophotometric2011.pdf (287.8Kb) -
Hudson, Athol; Grobler, Sias; Harris, Angela (Master Publishing Group, 2011)[more][less]
Abstract: The purpose of the study was to assess the relative base designs of three different maxillary molar stainless steel brackets with reference to the shear bond strength of three different adhesive resins. The molar brackets used were Victory series (3M Unitek), Upper Molar (GAC) and Optimesh XRT (Ormco). The adhesives used were Transbond XT (3M Unitek), Enlight (Ormco) and Sure Ortho Light Bond (Sure Orthodontics). The human enamel specimens (144) were randomly divided into nine groups and each group (n=16) was allocated to a bracket/adhesive combination. The contact surface of each of the bracket bases was measured three dimensionally using a reflex microscope. The base designs were also subjected to further microscopic investigations. The brackets were bonded to the enamel, temperature cycled and the shear bond strength was measured. The size and design of each of the brackets was different. The base size, surface treatment, mesh strand diameter and aperture size of the bracket base mesh have a significant effect on the shear bond strength at the bracket/adhesive interface. The shear bond strengths of all three Ormco bracket/adhesive resin combinations (5.8-6.8 MPa) were significantly lower (p<0.05; Kruskal-Wallis) than the other six bracket/adhesive combinations (9.4-12.1 MPa). The different adhesive types (3 types) could not be mainly responsible for the low shear bond values found for the Ormco bracket. The 3M Unitek combination of the Victory series bracket and Transbond XT adhesive proved to have a high shear bond strength without enamel damage. URI: http://hdl.handle.net/10566/558 Files in this item: 1
HudsonOrthodonticMolarBrackets2011.pdf (1.831Mb) -
Grobler, Sias; Chikte, Usuf; Westraat, Jaco (Hindawi Publishing Corporation, 2011)[more][less]
Abstract: The purpose of this study was to determine the pH levels of 29 different samples of methamphetamine on the street market in Cape Town. The sample was dissolved in water and the pH of each sample determined. The pH levels varied from 3.02 to 7.03 with an average of 5.0. Seventy-two percent (21) of the samples had a pH level below the saliva “critical pH point of 5.6” and therefore should cause significant damage to enamel, especially in hyposalivation subjects without a saliva flow. However, about 26% of the samples had a pH level close to the neutral point and should cause minor damage to enamel. To lessen enamel damage, subjects should exercise good oral hygiene practice, rinse with a fluoride-containing mouth rinse, drink artificially sweetened drinks, and eat cheese. It is concluded that most of the methamphetamine samples have a low enough pH to cause direct damage to enamel especially in hyposalivation subjects. URI: http://hdl.handle.net/10566/560 Files in this item: 1
-
Majeed, Abdul; Grobler, Sias; Moola, Mohamad H. (South African Dental Association, 2011)[more][less]
Abstract: 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. URI: http://hdl.handle.net/10566/579 Files in this item: 1
Majeedtoothwhiteningproducts2011.pdf (1.207Mb) -
Grobler, Sias; Louw, Adrian; Chikte, Usuf; Rossouw, Roelof; van Wyk Kotze, Theuns (Bentham Science Publishers, 2009)[more][less]
Abstract: 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. URI: http://hdl.handle.net/10566/404 Files in this item: 1
GroblerDrinkingWater2009.pdf (114.0Kb) -
Grobler, Sias; Hayward, R; Wiese, S; Moola, Mohamad H.; van Wyk Kotze, Theuns (Elsevier, 2010)[more][less]
Abstract: 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. URI: http://hdl.handle.net/10566/556 Files in this item: 1
GroblerSpectrophotometric2010.pdf (957.3Kb)
Now showing items 1-12 of 12