KALIDENT-Calcium Hydroxyapatite GENERAL DESCRIPTION KALIDENT-Calcium Hydroxyapatite is based on a formulation designed to significantly enhance the natural salivary remineralisation of dental enamel. Each day dental enamel is demineralised by acids present in the mouth and remineralised by the calcium and phosphate ions carried in saliva. Under normal circumstances the dynamic balance between demineralisation and remineralisation is stable. This equilibrium results in healthy teeth which are not affected by caries, and are not eroded, decalcified or hyper-sensitive. Poor oral hygiene, wrong dietary habits, excess consumption of carbonated beverages, occupational hazards can all increase the rate of demineralisation. The dynamic balance ions-salt can also be adversely affected by reductions in the salivary flow resulting from the normal ageing process, the use of many common drugs, the fitting of orthodontic appliances, dehydration through occupational or recreational activities and the radiotherapy and surgical interventions connected to some diseases. Saliva is normally super-saturated in calcium and phosphate ions (i.e. saliva carries the maximum possible amount of them) hence it was not possible to increase its ions concentration in order to compensate for the loss of tooth enamel caused by any of the above circumstances. The problem of carrying high concentrations of calcium and phosphate ions directly to the tooth surface could not be solved in this way . The regular use of KALIDENT-Calcium Hydroxyapatite over an extended period can do much to alleviate problems caused by excessive demineralisation of dental enamel. The use of KALIDENTCalcium Hydroxyapatite helps preventing caries or to stabilise rampant caries, counteracting the consequences of poor oral hygiene, acid foods and carbonated drinks. It can help prevent the dental consequences of xerostomia or Sjogren’s syndrome. It can even assist in the reversal of dental erosion and its adverse consequences. KALIDENT-Calcium Hydroxyapatite is a good alternative to those patients unwilling to use fluorides as part of their dental care regime.

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CLINICAL PROPRIETIES Laboratory tests indicate that the fully nanoparticle hydroxyapatite is twice as effective in restoring demineralised tooth enamel as its larger-particle parent structure. Over half the dry weight of human bone, 97% of dental enamel and 70% of dentine is comprised of hydroxyapatite. Human saliva, rich in calcium and phosphate ions, is a saturated solution of hydroxyapatite. Natural and synthetic hydroxyapatite have a strong affinity with the human body, and are used widely in orthopedic and dental applications (such as bone augmentation, dental cement, coatings for implants, etc.), as well as in foods, as a readily absorbed dietary calcium phosphate supplement. A joint study carried out by the Tokyo Medical and Dental University and Gifu Dental University shows a significant reduction in new caries formation in children who brushed their teeth daily with an hydroxypatite-based toothpaste compared with a non-hydroxyapatite control. KALIDENT-Calcium Hydroxyapatite repairs microscopic defects in surface and subsurface tooth enamel, restoring the enamel to its original mineral density and reversing incipient caries, the beginning of tooth decay. This restoration also returns the enamel to its original optical characteristics.

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MODE OF ACTION Demineralisation and remineralisation of tooth enamel occur naturally and constantly in the oral environment. The surface of the teeth is covered by a salivary pellicle, which can be colonized by bacteria to form dental plaque. Minute cracks and scratches in the enamel surface and spaces between the teeth that are inaccessible to a toothbrush especially harbour plaque. The enamel itself is comprised of closely packed rods of hydroxypatite, separated by minute channels, around 50 nanometers in size. Plaque bacteria digest carbohydrates and produce acids which seep into the minute channels between the enamel rods, causing the enamel to dissolve and become microscopically demineralised. Saliva however, has a restorative function, acting not only as a buffer, to reduce the acidity caused by plaque bacteria, but also as a constant source of calcium and phosphate ions. Upon neutralization of plaque acids, calcium phosphate complexes from the saliva diffuse back into the channels between the depleted enamel rods, replenishing the supply of hydroxyapatite. So that the enamel gets remineralised.

Prismi dello “crystal” smalto dicolumn un The enamel dente sano prima dell'intacco in healthy teeth before da parte ditoacidi. exposure acids

Demineralized enamel “crystal” columns destroyed by acids

Remineralized enamel “crystal” columns

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Under optimum physiological conditions, demineralisation and remineralisation are balanced in the oral cavity, so that no net loss of mineral from the teeth occurs. But conditions such as excess plaque, inadequate saliva flow, frequent intake of acidic foods or carbohydrates can upset the balance, driving the equation overwhelmingly in the direction of demineralisation, so that cavity formation eventually occurs. It is now known, however, that early-stage demineralisation (incipient caries or “white spot lesions”) can be reversed by replenishing or reinforcing the enamel, before decay requiring medical treatment sets in. 1. Adhesion to and Reduction of Plaque KALIDENT-Calcium Hydroxyapatite has a strong propensity to bind with protein, and adheres to plaque bacteria and glycoproteins in the oral cavity, facilitating their removal on rinsing the mouth after brushing. This feature of hydroxyapatite has been enhanced by reduction of its particle size through nanotechnology, so enormously increasing the surface area to which bacterial proteins attach. 2. Repair of Microscopic Surface Damage KALIDENT-Calcium Hydroxyapatite also acts as a filler, restoring minute cracks and scratches in surface tooth enamel. Reduction of its size to nanometre level has enhanced this ability of hydroxyapatite to enter and rebuild the crystalline network at the surface defects in the enamel. By filling minute surface lesions and restoring smoothness to the enamel, KALIDENT-Calcium Hydroxyapatite also reduces the number of sites on the tooth surface to which plaque is likely to adhere. Results of research in this area were presented at the IADR in early 2004.

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3. Remineralisation of Subsurface KALIDENT-Calcium Hydroxyapatite, having almost the same composition as our teeth, directly provides mineral to demineralised subsurface areas of the tooth (incipient caries), restoring the enamel to its near-natural state, without changing the composition of the enamel. This is in contrast to fluorides, which are not true remineralising substances by themselves, but promote teeth remineralisation by salivary calcium phosphate, by creating a new substance, fluorapatite, on the tooth surface. Fluorides tend to form a coating on the surface of the enamel, in contrast to hydroxyapatite, which tends to restore subsurface lesions from the deeper part of the lesion first. This deep restorative effect has been enhanced by the reduction of the hydroxyapatite particle size to two-figure nanometer size, facilitating their deeper penetration into the enamel.

FUNCTIONAL CLAIMS Features -Dental sensitivity -Remineralization and filling of surface lesions -Plaque clinical-physical removal -Acid antierosion -Bio-available calcium and phosphate ions -Boosts natural ability of saliva to remineralise tooth structure Alleviates: -Teeth Erosion -Dental White lesions -Rampant caries -Dental effects of acidic mouth -Enamel problems in newly-erupted teeth

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Bibliography The Journal of Cosmetic Whitening Vol.3 2005 Interaction of Small Crystal Form of Hydroxyapatite with Mutans Streptococci T. ARAKAWA, T. ISHIZAKI, R.E. HAYMAN, N. HANADA, and H. SENPUKU Journal of Dental Research Vol. 83, 2036, Honolulu Abstracts. Special Issue A. 2004 A New Enamel Restoring Agent for Use after PMTC M. NISHIO, H. KAWMATA, K. FUJITA, T. ISHIZAKI, R. HAYMAN, and T. IKEMI Journal of Dental Research Vol. 83, 1920, Honolulu Abstracts. Special Issue A. 2004

A New Enamel Restoring Agent for Use after Bleaching H. KAWAMATA, K. FUJITA, T. ISHIZAKI, R. HAYMAN, and T. IKEMI Journal of Dental Research Vol. 83, 1919, Honolulu Abstracts. Special Issue A 2004 Interaction of Small Crystal Form of Hydroxyapatite with Mutans Streptococci Journal of Dental Research Vol.82, B81-0548, Goteborg Abstracts, 2003 Two New Methods for Evaluation of Subsurface Enamel Lesions K. FUJITA, H. KAWAMATA, T. ISHIZAKI, R.E. HAYMAN, T. UCHIYAMA, M.KIMURA, H. KIBA, and T. IKEMI, Journal of Dental Research Vol.82, B78-0521, Goteborg Abstracts, 2003 Microhardness Testing to Evaluate Remineralization of Tooth Enamel T. FUJIMARU, T. ISHIZAKI, R.E. HAYMAN, and K. NEMOTO, Journal of Dental Research Vol.82, B77-0519, Goteborg Abstracts, 2003 Effect of hydroxyapatite toothpaste on vital tooth color C.GUO, H.LIU, and l. KATAYAMA Juan of Dental Research Vol.81, A254-1964, San Diego Abstracts, 2002 Adsorption Effect of Hydroxyapatite to Oral Streptococci T.ARAKAWA, T.ISHIZAKI, R.E.HAYMAN, N . HANADA,and H. SENPUKU Journal of Dental Research Vol.81, A200-1478, San Diego Abstracts, 2002 Remineralization Effects of Nanohydroxyapatite-Containing Dentifrice: a pH-Cycling Study Using Supernatant Remineralization by Nanohydroxyapatite-Containing Dentifrice: a pH-Cycling Study Using Slurry Post-Bleach Stain Inhibition by Nano-Hydroxyapatite: a Cyclical Staining Test Restoration of Post-Bleach Enamel Gloss Using a Non-Abrasive, Nano-Hydroxyapatite Conditioner Revolutionary Biomaterial for Improving Oral Health – Australian Made TERRY SLOUGH Auxiliary, May/June 2000 Binding Characteristics of Streptococcus mutans for Calcium and Casein Phosphopeptide R.K. ROSE, Division of Restorative Dentistry, The Dental School, Bristol, UK Caries Research 34:5:2000, 427-431

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A clinical trial of the anticaries efficacy of casein derivatives complexed with calcium phosphate in patients with salivary gland dysfunction K. DAVID HAY, W. URRAY THOMSON, Green Lane Hospital and University of Ontago Oral Surgery Oral Medicine Oral Pathology, March 2002 Xerostomia and you K DAVID HAY, KIM J GEAR New Zealand Journal 98: 46-51; 2002 Saliva and Oral Health EDGAR WM, O’MULLANE DM London: British Dental Association, second edition, London 1996 Circadian rhythms in flow rate and composition of human stimulated submadibular saliva FERGUSON DB, BOTCHWAY CA Archives of Oral Biology 24: 433-437, 1979 The Xerostomia Inventory: a multi-item approach to measuring dry mouth THOMSON WM, CHALMERS JM, SPENCER AJ, WILLIAM SM Community Dental Health 16: 12-17, 1998 Further testing of the xerostomia inventory THOMSON WM, WILLIAM SM Oral Surgery Oral Medicine Oral Pathology Oral Radiology and Endodontics Pilocarpine and other cholinergic drugs in the management of salivary gland dysfunction FERGUSON MM Oral Surgery Oral Medicine and Oral Pathology Anticariogenic complexes of amorphous calcium phosphate stabilized by casein phosphopeptides: A review REYNOLDS EC Special Care in Dentistry 18: 8-16, 1998 Quality of life and nutritional studies in patients with xerostomia HAY KD, MORTON RP, WALL CR New Zealand Journal 97: 128-137, 2001 The association of xerostomia and inadequate intake in older adults RHODUS NL, BROWN J. Journal of the American Dietetic Association 90: 1688-1692, 1990 Qualitative nutritional intake analysis of older adults with Sjogren’s Syndrome RHODUS NL Gerodontology 7: 61-69, 1998 The information on product specifications provided herein is only binding to the extent confirmed by Kalichem in a written Sales Agreement. KALICHEM EXPRESSLY DISCLAIMS ANY RESPONSIBILITY FOR THE SUITABILITY OF THE PRODUCTS FOR ANY SPECIFIC OR PARTICULAR PURPOSES INTENDED BY THE USER. Suggestions for the use and application of the products and guide formulations are given for information purposes only and without commitment. Such suggestions do not release Kalichem´customers from testing the products as to their suitability for the customer’s intended processes and purposes. Kalichem does not assume any liability or risk involved in the use of its products as the conditions of use are beyond its control. The user of the products is solely responsible for compliance with all laws and regulations applying to the use of the products, including intellectual property rights of third parties.

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EFFICACY TESTS 0547 Interaction of Small Crystal Form of Hydroxyapatite with Mutans Streptococci T. ARAKAWA1, T. ISHIZAKI1, R.E. HAYMAN1, N. HANADA2, and H. SENPUKU3, 1 Sangi Co, Ltd, Saitama, Japan, 2 National Institute of Public Health, Tokyo, Japan, 3 National Institute of Infectious Diseases, Tokyo, Japan Objectives: Hydroxyapatite (HA) is a component of biological hard tissue, including tooth enamel. Small crystal HA (scfHA) shows stronger adsorption to all streptococci than moderate (mcfHA) and large (lcfHA) crystal forms. We examined the potential effectiveness of scfHA as an agent for removing mutans streptococci from the oral cavity in a Dental Drug Delivery System (3DS) employing a drug-retainer formed to fit on individual dentition. First, bacterial adsorption to mcfHA and lcfHA formed by heating at 800 and 1200 degrees-centigrade respectively, and to two types of scfHA formed at 0 and 200 degrees-centigrade respectively was investigated in human saliva. Second, a clinical trial of 3DS using scfHA paste was performed in 5 human subjects. Method: in vitro (1) Streptococcus mutans were mixed with HA or saliva-coated HA (s-HA) in PBS, with and without addition of divalent metal ions Ca2+ and Mg2+ respectively, and incubated for 90 min at 37 degrees-centigrade. After standing of the mixtures at room temperature, the optical density of the supernatants (O.D.550) was analyzed to assess bacterial adsorption levels. in vivo (2) 3DS using the paste was applied to subjects 5 minutes per day for 1 week. Oral bacteria numbers were determined quantitatively by culture from stimulated saliva collected before and after the week of application. Results: Bacterial adsorption to s-scfHA was reduced by Ca2+, in a dose-dependent manner, while Mg2+ showed no effect on adsorption. This suggests that Ca2+ in saliva may disturb the bacterial adsorption effect of scfHA paste in the oral cavity. In the clinical trial, saliva testing 5 weeks after 3DS treatment showed that mutans streptococci were removed from oral cavity by 3DS with scfHA paste. Conclusion: ScfHA paste is an effective agent for removing mutans streptococci from the oral cavity in 3DS, especially if a drug-retainer system that avoids the influence of saliva is used.

1920 A New Enamel Restoring Agent for Use after PMTC M. NISHIO1, H. KAWMATA1, K. FUJITA1, T. ISHIZAKI1, R. HAYMAN1, and T. IKEMI2, 1Sangi Co., Ltd, Tokyo, Japan, 2Nihon University at Matsudo, Japan Objective: Professional mechanical tooth cleaning (PMTC), which uses abrasives to remove biofilms and other surface deposits, also causes microscopic damage to tooth enamel. This can lead to early return of plaque, and in fact increase the risk of caries and periodontal disease. We developed and tested an agent designed to restore tooth enamel to its original state after PMTC treatment. Method: Extracted human anterior teeth without previous restorative treatment, caries or white-spot lesions were polished with a commonly used PMTC abrasive agent. The teeth were then polished with a hydroxyapatite-based agent designed to restore the enamel surface (PRTC Super Fine, SANGI). The enamel surface was observed before PMTC, after PMTC, and after post-PMTC polishing with the enamel restoring agent, using a scanning probe microscope (SPM) (SPI4000, Seiko Instruments) and a scanning electron microscope (SEM) (S-4500, HITACHI). SPM observation allowed both qualitative (three dimensional) and quantitative (computed) evaluation of the enamel surface at each stage of processing. Result: SPM observation showed some coarseness in the enamel surface prior to PMTC treatment, believed to result from tooth brushing and other normal abrasion. The enamel surface after PMTC treatment was much coarser, both qualitatively and quantitatively, indicating that further damage to the surface enamel had occurred. After post-PMTC polishing with the enamel restoring agent, the enamel surface closely resembled that prior to PMTC treatment, suggesting that restoration of the enamel had occurred. SEM observation confirmed that the enamel surface was rougher after PMTC treatment than before, and that after postPMTC treatment with the new enamel restoring agent, it closely resembled the original enamel surface. Conclusion: The hydroxyapatite-based agent tested effectively restores post-PMTC tooth enamel to its near-original state. We called this new agent PRTC ( eProfessional Re-enamel Tooth Cleaning') Super Fine, to distinguish it from traditional PMTC polishing agents.

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1919 A New Enamel Restoring Agent for Use after Bleaching H. KAWAMATA1, K. FUJITA1, T. ISHIZAKI1, R. HAYMAN1, and T. IKEMI2, 1Sangi Co., Ltd, Tokyo, Japan, 2Nihon University at Matsudo, Japan Objective: In-office bleaching is widely practised and appears to have little adverse effect on the teeth. But hypersensitivity and relapse of discoloration often occur, requiring regular follow-up to ensure patient well-being. We postulated that sensitivity and relapsed discoloration result from microstructural changes to the enamel surface during the bleaching process, and developed a new enamel restoring agent and examined its effect on the post-bleach enamel surface. Method: Specimens of extracted human anterior teeth without previous restorative treatment, caries or white-spot lesions were subjected to bleaching with Hi-Lite (Shofu), according to the maker's instructions. After bleaching, the teeth were polished with a newly developed hydroxyapatite-based agent designed to restore the enamel surface (PRTC Super Fine, SANGI). The microstructure of the enamel surface was observed before bleaching, after bleaching, then after post-bleach polishing with the enamel restoring agent, using a scanning probe microscope (SPM) (SPI4000, Seiko Instruments) and a scanning electron microscope (SEM) (S-4500, HITACHI). SPM observation allowed both qualitative (three dimensional) and quantitative (computed) evaluation of the enamel surface at each stage of processing. Result: SPM observation showed some coarseness in the enamel surface prior to bleaching, believed to result from tooth brushing and other normal abrasion. In comparison, the enamel surface after bleaching was much coarser, suggesting that damage to the microstructure had occurred. After post-bleach polishing with the enamel restoring agent, the surface resembled that of the original enamel surface prior to bleaching, suggesting that restoration of the microstructure had occurred. SEM observation also showed that the enamel surface was rougher after bleaching than before, and that after post-bleach polishing with the enamel restoring agent, the surface resembled that of pre-bleach enamel. Conclusion: We concluded that treatment of bleached enamel with the hydroxyapatite-based agent PRTC Super Fine restored the enamel surface to a condition similar to that of pre-bleach enamel.

1478 Adsorption Effect of Hydroxyapatite to Oral Streptococci T. ARAKAWA1, T. ISHIZAKI1, R.E. HAYMAN1, N. HANADA2, and H. SENPUKU2, 1Sangi Co, Ltd, saitama, Japan, 2National Institute of Infectious Diseases, tokyo, Japan Objectives:Hydroxyapatite (HA) is a component of biological hard tissue, including tooth surface enamel, and has high ability to adsorb oral streptococci. To investigate whether HA is a useful agent for Dental Drug Delivery System (3DS Formulation or device that delivers therapeutic agent(s) to desired body location(s) and/or provides timely release of therapeutic agent(s).:), a new system for specifically removing oral streptococci from the oral cavity, the relationship between bacterial adsorption and crystal growth of HA heated at different temperatures (0, 200, 800 and 1200°C) was analyzed by in vitro assay using 550 nm light absorbance. Methods:Oral streptococci (Streptococcus mutans, S. sobrinus, S. sanguis, S. mitis, S. salivarius, S. anginosus) mixed with HA or saliva-coated HA (s-HA) in PBS were incubated for 90 min at 37°C. After standing of the mixtures at room temperature, the supernatants were analyzed for the difference in optical densities before and after the application of HA or s-HA, to assess bacterial adsorption levels. The bacterial adsorption to HA was also observed by SEM. Results:Non- and 200°C-heated HA and s-HA showed strong adsorption to all streptococci in comparison with high heat-treated (800°C and 1200°C) HA and s-HA. Interestingly, s-HA heated at 800°C showed a high property of adsorption to S. mutans and S. mitis (more than 80%) and low property to S. sobrinus and S. salivarius (less than 20%). Moreover, SEM observation indicated that the adsorption levels were dependent on crystal size of HA. Conclusions:These results suggested that non- or lower heat-treated forms of HA might be useful as agents for 3DS.

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0187 Remineralization Effects of Nanohydroxyapatite-Containing Dentifrice: a pH-Cycling Study Using Supernatant A. ITTHAGARUN, N.M. KING, and M. CHEUNG, University of Hong Kong, Saiying Pun, Hong Kong Objective: to compare the effects of a dentifrice containing nano-hydroxyapatite (nHA) with a fluoride dentifrice on the remineralization of artificial enamel caries-like lesions, using a supernatant of each dentifrice preparation (the method commonly employed to assess the remineralization effect of fluoride, which is believed to occur at an ionic level) in a pH cycling model. Methods: Sound extracted third molars with artificial lesions, 100-120µm deep, were cut into sections 100-150µm thick. Each specimen was studied using polarized light microscopy and microradiography to evaluate the lesion depth (LD) and the mineral content of the lesions before and after 10 days of pH cycling. Each cycle involved three hours of demineralization twice a day, with two hours' immersion in a remineralizing solution approximating human saliva between demineralization, and another 16 hours similar immersion overnight. One-minute treatments with a supernatant of the selected dentifrice preparations were performed thrice daily, before the first demineralization and before and after the second demineralization. Thirty-three sections were randomly divided into three groups, Group 1: 950ppm NaF dentifrices; Group 2: dentifrices with no active ingredients (-ve control) and Group 3: 10% nHA dentifrices. Results: After 10 days pH cycling, the lesion depth decreased by 23% and 15% in Groups 1 and 3, respectively, while those in Group 2 showed an obvious increased in lesion depth by 78%. Groups 1 and 3 were significantly different from Group 2 (p0.05, ANOVA and SNK test). Conclusion: Based on the data obtained from this pH cycling model, using supernatant preparations of dentifrices, the dentifrice that contained 10% nHA showed no significant difference in healing efficacy from the dentifrice that contained 950ppm NaF. This study was supported by Sangi Co., Ltd. Japan

0186 Remineralization by Nanohydroxyapatite-Containing Dentifrice: a pH Cycling Study Using Slurry N.M. KING, A. ITTHAGARUN, and M. CHEUNG, University of Hong Kong, Saiying Pun, Hong Kong Objective: To compare the effects of dentifrices containing nano-hydroxyapatite (nHA) with fluoride dentifrices on the remineralization of artificial enamel caries-like lesions using slurry preparations (a method designed to allow for the postulated action of hydroxyapatite at nanocrystalline and ionic levels) in a pH cycling model. Methods: Extracted third molars with artificial lesions, 100-120µm deep, were sectioned to 100-150µm thick. Specimens were studied using polarized light microscopy and microradiography to evaluate the lesion depth and the mineral content before and after 10 days of pH cycling. Each cycle involved three hours of demineralization twice daily, with two hours' immersion in a remineralizing solution approximating human saliva between demineralization, and another 16 hours similar immersion overnight. One-minute treatments with a slurry of the selected dentifrice preparation were performed thrice daily, before the first demineralization and before and after the second demineralization. Fifty-five sections were randomly divided into five groups, Group 1: 900ppm MFP dentifrice (+ve control 1); Group 2: 900ppm NaF dentifrice (+ve control 2); Group 3: 10% nHA type A; Group 4: 10% nHA type B and Group 5: -ve control. Results: Lesion depth decreased by 4% in Group 1 and 5% in Groups 2, 3 and 4. Those in Group 5 increased by 27%. Groups 1, 2, 3 and 4 were significantly different from Group 5 (p0.05, ANOVA and SNK test). Conclusions: The dentifrices that contained 10% nHA showed no significant difference in healing efficacy from the dentifrices that contained fluoride. The pH cycling method using slurry preparations of dentifrices, can be successfully used to compare the remineralization effects of nHA and fluoride-containing dentifrices. This study was supported by Sangi Co., Ltd. Japan.

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1671 Post-Bleach Stain Inhibition by Nano-Hydroxyapatite: a Cyclical Staining Test M. NISHIO, K. FUJITA, T. ISHIZAKI, and R. HAYMAN, SANGI Co., Ltd, Tokyo, Japan "Objective:" Office bleaching is widely used as a means of non-abrasive whitening, but is often accompanied by problems of sensitivity and relapsed discoloration believed to result from microstructural changes to the enamel during the bleaching process. We developed a nano-hydroxyapatite conditioner designed to restore tooth enamel by mineral replacement, and examined its effect on the post-bleach enamel surface and the return of post-bleach extrinsic stains, using a new cyclical staining test. "Method:" Extracted human teeth with sound enamel were bleached with Opalescence® (Ultradent) according to the maker's instructions, then immersed in a solution of nano-hydroxyapatite conditioner overnight. The specimens were observed by SEM and SPM before and after bleaching and after treatment with the conditioner. A cyclical staining test was developed to assess relapse of stains, using one group of specimens treated by bleaching only, and another treated by bleaching followed by immersion in the conditioner. Each group was placed in red wine for 4 hours' staining, followed by 1 hour in an oxygen-purged incubator for colorfixing, then 30 minutes in a 10% polyethylene glycol 400 solution for stain-removal, and this cycle repeated 3 times. Color was measured for each specimen at the start of testing and after each cycle using a spectrophotometer (Murakami Color Research) and digital camera (Canon Inc.) . "Results:" SEM and SPM showed the post-bleach enamel surface was smoother for nano-hydroxyapatite-treated specimens than for untreated specimens. Cyclical staining showed much greater stain relapse in untreated specimens than in those treated with the nanohydroxyapatite conditioner, which retained a glossy, sparsely stained surface similar to that of sound enamel, even after three staining cycles. "Conclusion:" We concluded that the nano-hydroxyapatite conditioner is an effective agent for use after bleaching, restoring a smooth surface to the enamel and inhibiting relapse of extrinsic tooth stains.

1670 Restoration of Post-Bleach Enamel Gloss Using a Non-Abrasive, Nano-Hydroxyapatite Conditioner R. TAKIKAWA, K. FUJITA, T. ISHIZAKI, and R. HAYMAN, SANGI Co., Ltd, Tokyo, Japan "Objective:" Increasing demand for esthetic dentistry has led to an increase in recent years in the spread of vital tooth bleaching. The aim of bleaching is to improve the color and brightness of teeth, but it can result in postoperative changes such as roughness in the enamel surface which are seen as white turbidity or lack of gloss to the naked eye. We developed a non-abrasive, nano-hydroxyapatite conditioning agent designed to restore tooth enamel by mineral replacement, and examined its effect on the post-bleach enamel surface, in particular enamel gloss. "Method:" Sound extracted human teeth were cut into approximately 4×5×3 mm blocks and polished under running water with successive levels of abrasive paper (Buehler UF1200, UF800 and #600) to a standard enamel surface gloss of 200±10, as measured by surface gloss analyzer (SGA) (806H Tricor Systems Inc.). The specimens were then bleached with Hi-Lite (Shofu), according to the maker's instructions, and divided into two groups, one of which was then immersed in a solution of nano-hydroxyapatite conditioner overnight. All specimens were observed by SPM (Seiko Instruments) at the start of the experiment, after bleaching and, for the second group, after treatment with the nano-hydroxyapatite conditioner. SGA was repeated for both groups at the close of the experiment. "Result:" SPM and SGA showed surface roughness increased and glossiness decreased in all specimens after bleaching. But in the group then treated with nano-hydroxyapatite conditioner, surface roughness decreased and glossiness was seen to improve. "Conclusion:" Our results showed a correlation between the gloss and smoothness of surface enamel. We concluded that the nanohydroxyapatite conditioner is effective in restoring smoothness and gloss to post-bleach enamel, and could be a useful adjunct to the bleaching process, improving both its esthetic outcome and customer satisfaction.

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1964 Effect of hydroxyapatite toothpaste on vital tooth color C. GUO1, H. LIU1, and I. KATAYAMA2, 1Peking University, Beijing, China, 2Meikai University School of Dentistry, Sakado, Saitama Pref, Japan Objectives: Hydroxyapatite (HAP) adsorbs cariogenic bacteria and remineralizes subsurface demineralized areas of tooth enamel, and is a registered anticaries toothpaste ingredient in Japan. We examined its effect on tooth color, which reportedly changes up to 2 Lumin shades when treated with bleaches like hydrogen peroxide. Method: Two 6-person groups brushed their teeth 5 minutes 3 times daily for 30 days, one using HAP toothpaste (Apagard, Sangi Co., Ltd.) and the other an identical toothpaste without HAP. The color of subjects' central incisors was measured initially, then every 2-3 days (3 measurements each at the center of the labial surface) using a Photoresearch Spectra-Scan PR-650 photocolorimeter. The difference between initial and final average CIE L*a*b* values ( E) was calculated for each subject and compared with the average E for reddish brown tabs (A1 through A4) and reddish yellow tabs (B1 through B4) on the Lumin Vacuum guide, calculated using a Murakami CMS-35FS spectrophotometer. Two groups of extracted human teeth were brushed 5 minutes 3 times daily for 7 days using the same toothpastes respectively, then examined by SEM (Hitachi S-4500). Results: Vital teeth in the HAP group showed increased L* and an average E of 3.48, against 1.45 and no change in L* for the non-HAP group. Comparison with Lumin average E values (2.52 for A tabs and 3.55 for B tabs) showed the HAP group color change was equivalent to 1.4 shades on the reddish brown scale and 1.0 shade for reddish yellow. SEM observation showed a fine particle coating on extracted teeth in the HAP group, but not in the non-HAP group. Conclusion: Though less powerful than harmful bleaches, the results suggest HAP toothpaste can alter tooth color by at least one shade with daily brushing, and this effect may be related to its plaque-adsorbtion and enamel remineralization properties.

In Vitro Studies of Dental Plaque Formation: Adsorption of Oral Streptococci to Hydroxyaptite. BENJAMIN APPELBAUM ¹, ELLIS GOLUB ², STANLEY C. HOLT ³, and BURTON ROSAN ¹ Departments of Microbiology ¹ and Biochemistry ², School of Dental Medicine and Center for Oral Health Research, University of Pennsylvania, Philadelphia, Pennsylvania 19104, and Department of Microbiology, The University of Massachusetts, Amherst, Massachusetts 01003 ³ A mixture of saliva-coated hydroxyapatite beads and radioactively labeled bacteria has been employed as an in vitro model for the initial phase of dental plaque formation. Adsorption in this model can be expressed by the Langmuir adsorption isotherm, and the adherence of oral streptococci can be expressed as the product of the affinity constant (Ka) and the number of binding sites (N), KaN. With this approach, Streptococcus sanguis serotype 1 strains adhered better (KaN = [187 +/72] X 10(-2)) than serotype 2 strains (KaN = [97 +/- 84] X 10(-2)); a t test showed this difference to be statistically significant to the 99.99% confidence level. Strains of S. mitis, S. mutans, and S. salivarius did not appear to adhere as well. To analyze the bacterial receptors involved in adherence, competition studies in which increasing quantities of unlabeled bacteria were added to a fixed quantity (4 X 10(9) cells per ml) of 3H-labeled serotype 1, reference strain S. sanguis G9B, were performed. These studies indicated that the type 1 strains competed for the same, or closely related, binding sites. Competition studies using serotype 2 S. sanguis strains resulted in an increased binding of reference strain G9B to hydroxyapatite. Scanning electron microscopy indicated this effect was due to the formation of localized aggregations of bacteria, presumably representing the two bacterial types. The results of competition studies with S. mitis were variable, and several strains of other oral bacteria showed little or no competition.

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