Tooth bleaching: its effect on oral tissues.

After investigating the literature, we suggest these guidelines for tooth bleaching: If bleaching solutions of high concentration are used, prevent accidental exposure of gingival tissues to the solutions by use of a rubber dam. If using lower concentrations of bleaching solutions, avoid long-term exposures to gingival tissues. To maintain pulp vitality, keep bleaching time and temperatures to a minimum. Check teeth for exposed dentin and enamel fractures. Advise patients that thermal sensitivity may occur after the bleaching procedure and may persist for several days. Prescribe premedication with an anti-inflammatory drug, when necessary. Avoid bleaching the cervical area of the tooth by covering the area with a base to avoid cervical resorption. Avoid dentin exposure by noting that abrasive bleaching techniques can remove significant amounts of enamel. Take special care when bleaching enamel--especially near the cervix of the tooth, where the enamel is thin.     

Antibacterial effect of silver-zeolite on oral bacteria under anaerobic conditions

OBJECTIVES: The purpose of this study was to evaluate the antibacterial effect of silver-zeolite (SZ) against oral bacteria under anaerobic conditions. METHODS: The antibacterial activity of SZ was evaluated by determining the minimum inhibitory concentrations (MICs) using two-fold serial dilutions of SZ in Brain Heart Infusion broth. Release of Ag+ into the broth was measured by an atomic absorption technique. RESULTS: SZ inhibited the growth of the bacteria tested under anaerobic conditions. The MIC of SZ ranged between 256 and 2048 micrograms/ml, which corresponded to a range of 4.8-38.4 micrograms/ml of Ag+. All strains grew in broth containing 16,384 micrograms/ml of type-A zeolite. SIGNIFICANCE: These results suggested that SZ may be a useful vehicle to provide antibacterial activity to dental materials used even under anaerobic conditions such as deep in the periodontal pocket.     

Fibrinolytic activity of oral anaerobic bacteria.

We assayed 13 species of anaerobic microorganisms found in the human oral cavity for fibrinolytic activity. Activity was detected in 6 of 6 strains of Bacteroides melaninogenicus subsp. asaccharolyticus, 3 of 3 strains of Bacteroides oralis, and 11 of 12 strains of Treponema denticola. The activity observed in Bact. oralis was variable and was the only species that required plasminogen. The fibrinolytic activity of T. denticola was extracellular. The culture supernatant was concentrated by ultrafiltration, fractionated with ammonium sulphate, then applied to a column of 2 per cent agarose. This resulted in a 1750-fold purification. The purified T. denticola fibrinolysin had only one major band on polyacrylamide gel electrophoresis, and an apparent molecular weight near 1,000,000. It was not inactivated by heating at 75 °C for 10 min and was stable from pH 5.5 to 9.5. The enzyme appeared to be an aggregation of smaller molecules. The fibrinolytic enzyme of Bact. melaninogenicus subsp. asacch. was bound to the cell membrane and shared many properties with the collagenase reported by others. The activity of this enzyme was enhanced by treatment with SDS.     

Vital tooth bleaching in dental practice: 1. Professional bleaching

As dental health improves, with the concurrent drop in the provision of basic restorative care, patients are now asking their dentists to provide aesthetic treatments rather than the treatment of disease. Tooth bleaching is one such treatment that is frequently described in consumer magazines and television shows, driving consumer interest in this, apparently, benign therapy. This three-part series demonstrates the techniques that can be employed, within the dental practice or under the supervision of a clinician, those systems that can be bought by patients over the counter and, finally, a discussion of the biological effects of peroxide-containing solutions and the legal position on such products in the UK. In this section, we will describe the common methods by which teeth can be bleached, either by the clinician directly, or under his/her supervision by the use of'at home' kits. Efficacy and safety issues will be described. CLINICAL RELEVANCE: Clinicians should be able to discuss the merits, risks and likely success of a variety of bleaching treatments with their patients and, in doing so, assist in the process of obtaining informed consent.     

Vital tooth bleaching: review and current status.

Vital tooth bleaching refers to the clinical application of a chemical solution to a tooth surface in order to achieve a lightening effect. This article reviews the available literature to address the following questions: What are the methods of vital bleaching? How does vital bleaching work and is it effective? What effects are there on the teeth, dental restorative materials, soft tissues and systemic health? The techniques used in the application of dentist-applied and patient-applied bleaching systems are described. Generally, vital tooth bleaching has been found to be effective, however, relapse does occur. The literature suggests that bleaching agents may have transient effects on the tooth itself, and may affect some dental materials. Soft tissues exposed to hydrogen peroxide for prolonged periods show changes consistent with inflammation or hyperplasia. Hydrogen peroxide may also potentiate the carcinogenic effect of known carcinogens. However, more clinically relevant studies are needed. Until long-term safety data becomes available, the dental practitioner should approach the use of in-home bleaches with caution. The U.S. Food and Drug Administration (FDA) recently classified these products as "new drug." However, dentist-applied bleaching gel systems are a viable alternative and deserve further consideration. They are simple to use, require little armamentarium, and limit the exposure of the bleaching agent to the teeth only. Vital tooth bleaching refers to the clinical application of a chemical solution to a tooth surface in order to achieve a lightening effect. There was a resurgence of interest in vital bleaching with the recent introduction of the in-home bleaching technique.(ABSTRACT TRUNCATED AT 250 WORDS)     

Vital tooth bleaching in dental practice: 2. Novel bleaching systems

This paper describes some of the novel commercial approaches to tooth bleaching. Known as 'direct-to-consumer' products there are two main systems available, one employing coated, cellulose strips and the other a paint-on gel. A further development is the production of dentifrices that contain active hydrogen peroxide, made possible by the use of dual chambered tubes. Each of the systems is described and demonstrated and an overview of the research supporting their safe, effective use is presented in each case. It is likely that our patients have access to these products and, hence, it is important that we are aware of their strengths and weaknesses. CLINICAL RELEVANCE: The systems described within this paper are available for sale in Europe and over the internet. Patients may well be using, or planning to use, them and may ask for professional advice.     

An overview of bleaching techniques: 2. Night Guard Vital Bleaching and non-vital bleaching

Night Guard Vital Bleaching (NGVB) or dentist-monitored bleaching technique is probably the most widely used bleaching technique because of its relative ease of use, low cost, safety and high success rate. There are many non-vital bleaching techniques available, all of which have one thing in common, usually a successful result in the procedure returning the discoloured tooth to its original colour and beyond that when required. This article will give an overview of various home bleaching techniques: materials and regimens used, bleaching procedure and treatment of side-effects. In addition, it will review various in-surgery and at home techniques used for bleaching non-vital teeth.     

Effect of oral antiseptic agents on phospholipase and proteinase enzymes of Candida albicans

ObjectiveCandida-associated denture stomatitis is the most prevalent form of oral candida infections among the denture wearers. Generally, antiseptic oral rinses used in the treatment of these infections are considered as an adjunct or alternative antifungal treatment. Studies have suggested that the intraoral concentrations of antiseptics decrease substantially to the sub-therapeutic levels on account of the dynamics of the oral cavity. This condition yields the question about the minimum antiseptic concentration that effect the character or pathogenesis of Candida during treatment. The extracellular phospholipase and proteinase enzymes of Candida albicans are regarded to have a crucial role in the pathogenesis of human fungal infections. Therefore, the aim of this study was to investigate the effect of different sub-therapeutic concentrations of chlorhexidine gluconate, hexetidine and triclosan on the production of these enzymes by C. albicans strains isolated from 20 patients with denture stomatitis.MethodsPhospholipase test was done by using Sabouraud dextrose agar with egg yolk, proteinase test was done by using bovine serum albumin agar.MethodsPhospholipase test was done by using Sabouraud dextrose agar with egg yolk, proteinase test was done by using bovine serum albumin agar.ResultsExoenzyme production of 20 strains which were brief exposured to sub-therapeutic concentrations of three antiseptic agents decreased significantly compared with the strains that were not exposured with antiseptic values (p < 0.05). There was significant difference between the sub-therapeutic concentrations of each of three antiseptics (p < 0.05). When the same concentrations of each antiseptic was compared, there were no significant differences between enzymatic activities (p > 0.05).ConclusionsThe results of this study show that sub-therapeutic levels of each antiseptic may modulate candidal exoenzyme production, consequently suppressing pathogenicity of C. albicans.     

Vital bleaching: a new light-activated hydrogen peroxide system.

With ever increasing interest in cosmetic enhancement of dentition by dentists and patients alike, this article introduces a new light-activated bleaching system that adds up to total patient satisfaction and reduced chair time. The chairside application of hydrogen peroxide 30% was effective in lightening a moderate case of tetracycline staining. The uniqueness of this system allows the practitioner complete control within an office setting, and it provides the patient with an immediate result. The ease of application and strict supervision of a dentist has allowed this system to satisfy recent watchdogs of the Federal Drug Administration.     

Intracoronal isolating barriers: effect of location on root leakage and effectiveness of bleaching agents.

The purpose of this study was to evaluate the ability of several intracoronal isolating barrier materials to prevent leakage of a bleaching agent into the roots of teeth and to determine whether placement of the barrier material at the cementoenamel junction or below the cementoenamel junction has an effect on the bleaching results of the crowns. Fifty teeth were stained in vitro, and gutta-percha fillings were placed in the root canals. The experimental isolating barriers were placed at the cementoenamel junction or 2 mm below the cementoenamel junction. A walking bleach of Superoxol and sodium perborate was placed in the pulp chamber for three treatments. The roots of the teeth were evaluated for the presence of root decoloration, and the crowns of the teeth were evaluated for bleaching effect. Findings from this study showed a significant difference between gutta-percha alone and gutta-percha with barrier in preventing root decoloration (p less than 0.05). No significant differences were found between the other experimental groups in preventing root decoloration. Placement of an intracoronal isolating barrier material 2 mm below the cementoenamel junction resulted in a more acceptable esthetic bleaching result of the crowns than did placement of barrier material at the cementoenamel junction.     

Post-operative bleaching: effect on microleakage.

The effect of a carbamide peroxide bleaching gel on the microleakage of Class V resin composite restorations with two dentin bonding agents was evaluated using extracted human teeth. Class V cavity preparations were placed at the cementoenamel junction of the facial and lingual surfaces of 20 teeth for a total of 40 preparations. Half of the teeth were restored with Scotchbond 2/Silux Plus and half were restored with Prisma Universal Bond 3/AP.H. Five teeth were randomly selected from each of the two groups and were stored in water at 37 degrees C to serve as controls. The remaining teeth were exposed to a carbamide peroxide gel for three 2-hour periods per day for 9 days. The specimens were stored in distilled water at 37 degrees C except during treatment periods. All teeth were then thermally stressed for 100 cycles. Microleakage was assessed by dye penetration. The results demonstrated that the carbamide peroxide agent adversely affected the marginal seal of both restorative systems.     

Amixicile targets anaerobic bacteria within the oral microbiome

ObjectivesAnaerobic bacteria are the major causative agents of periodontal disease. However, so far, targeted therapy aimed at reducing those pathogens has not been widely implemented. We have previously reported on a novel antimicrobial, amixicile, that targets anaerobic bacteria through inhibition of the function of the major anaerobic metabolic enzyme pyruvate ferredoxin oxidoreductase (PFOR), while not affecting aerotolerant organisms. It effectively inhibited the growth of oral anaerobes both in monocultures as well as in mixed in vitro mixed cultured however, amixicile's activity in in vivo-like conditions remained to be established.MethodsHere, we expand our study using an ex vivo oral microbiome combined with metagenomic sequencing to determine the effect of amixicile treatment on the composition of the microbiome and compare it to that of metronidazole.ResultsOur results show that in the complex microbiomes, anaerobic bacteria are selectively inhibited, while the growth of aerotolerant ones, such as Streptococcus, Klebsiella, Neisseria, and Rothia is unaffected. Veillonella was the most abundant anaerobic genus in our ex vivo microbiome, and we observed complete inhibition of its growth. In addition, growth of other anaerobes, Fusobacterium and Prevotella, was significantly inhibited. It is noteworthy that a change in abundance of bacteriophages, such as Siphoviridae and Myoviridae, associated with the oral microbiome was observed.ConclusionsCollectively, our data expand on the so far reported inhibitory spectrum of amixicile and demonstrates that it inhibits anaerobic bacteria, including both clinical isolates and laboratory strains.     

Comparative study of the effects of two bleaching agents on oral microbiota

This study evaluated the in vivo effects of bleaching agents containing 10% carbamide peroxide (Platinum/Colgate) or 7.5% hydrogen peroxide (Day White 2Z/Discus Dental) on mutans Streptococcus during dental bleaching. The products were applied on 30 volunteers who needed dental bleaching. In each volunteer, one of the two bleaching agents was used on both dental arches one hour a day for three weeks. Analysis of the bacterial counts was made by collecting saliva before (baseline values), during (7 and 21 days) bleaching treatments and 14 days posttreatment. The Friedman non-parametric analysis (alpha=0.05) found no differences in microorganism counts at different times for each group for both agents (p>0.05). The Mann Whitney nonparametric test (alpha=0.05) showed no differences in micro-organism counts for both agents (p>0.05). Different bleaching agents did not change the oral cavity mutans Streptococcus counts.     

The whitening effect of bleaching agents on tetracycline-stained rat teeth

This study compared the whitening effect of three bleaching agents on the teeth of rats and demonstrated differences in bleaching where dentin was exposed or enamel was thin. Thirty Albino rats were peritoneally injected with tetracycline solution daily for two weeks. Thirty-two disc-shaped specimens were cut from the crowns of incisors removed from sacrificed rats and were irradiated with UV light for 16 hours. Sections were stored in saline. Eight sections served as controls and were not bleached. Three bleaching agents (Opalescence, Rembrandt and Nite White) were applied to eight specimens each, five times a day for two weeks, and images of the sections were recorded at the following times: before bleaching (baseline), day 1, day 3, day 5, day 7, day 9, day 11 and day 14. Mean colors to demonstrate any change (deltaE) from baseline for each time period were as follows: control-9.78 (baseline), 9.17, 9.36, 9.65, 9.40, 9.99, 10.57, 11.36; Opalescence-10.08, (baseline) 7.63, 6.72, 6.04, 5.10, 4.87, 4.89, 4.27; Rembrandt-9.83 (baseline), 11.27, 9.55, 8.36, 7.75, 6.94, 7.11, 7.04; Nite White-10.44 (baseline), 9.92, 7.58, 6.80, 5.45, 5.05, 4.73, 4.01. All bleached teeth were lightened (p<.01). Another 56 tetracycline-stained rat incisors were UV irradiated for three days. Three different penetration depths were tested: penetration through lingual dentin and labial enamel (DN group), penetration through labial enamel only (RE group) and penetration through labial enamel covered with 1.0 mm human enamel (HE group). Specimens were bleached with Opalescence for one hour five times a day for one week or four weeks. A control group of unbleached teeth was also examined. Results (deltaE) were as follows: control--11.67; 1-week DN--13.55; 1-week RE--12.80; 1-week HE--12.07; 4-week DN--7.48; 4-week RE--7.50; 4-week HE--11.69. The color change in the 4-week DN and the 4-week RE groups showed the greatest reduction (p<.01).     

Activity of endodontic antibacterial agents against selected anaerobic bacteria

The antimicrobial activity of substances used as antibacterial agents (solutions of 10% calcium hydroxide, camphorated paramonochlorophenol - PMCC, 2% chlorhexidine digluconate and 10% castor oil plant detergent) on anaerobic bacteria (Fusobacterium nucleatum ATCC 25586, Prevotella nigrescens ATCC 33563, Clostridium perfringens ATCC 13124 and Bacteroidesfragilis ATCC 25285), using a broth dilution technique, was evaluated in vitro. For determination of minimum inhibitory and minimum bactericide concentrations (MIC and MBC), two culture broths, Reinforced Clostridial Medium (RCM) and supplemented Brucella, standardized inoculum and serially diluted solutions were used. All antibacterial agents presented antimicrobial activity that varied for different bacteria. There were no differences in the performance of the two broths. Chlorhexidine digluconate was the most effective, with the lowest MICs, followed by castor oil detergent, PMCC and calcium hydroxide. C. perfringens and B. fragilis were the most resistant bacteria to all agents.     

Sterinole and cetylpirydine chloride influence on non-sporulated anaerobic bacteria of oral cavity

Sensibility (MBC--Minimal Bactericidal Concentration) of 97 strains of non-sporulated anaerobic bacteria separated from clinical material from oral cavity to Sterinole (Polfa) and cetylpirydine chloride has been examined. Experiments have been carried out by means of suspension method adapted appropriately to the tests on non-sporulated anaerobes. 72 hours' cultures of strains containing 10(9) of live bacterial cells in 1 ml have been used as inoculum. MBC readings have been performed after 7 days' incubation at temperature of (37 degrees C) 310 degrees K. From the total number of 97 strains under examinations 34 strains were sensible to low concentration of Sterinole equal to 7.8 to 15.5 micrograms/ml. Further 19 strains exacted MBC within 15.6 to 31.1 micrograms/ml and further 40 strains perished in the antiseptic concentration of 31.2 to 62.4 micrograms/ml. The remaining 4 strains exacted concentration of 62.5 to 125 micrograms/ml to be perished. Among 97 strains 29 strains were perishing in low concentrations of cetylpirydine chloride equal to 7.8 to 15.5 micrograms/ml. Successive 25 strains were damaging by the antiseptic concentration equal to 15.6 to 31.1 micrograms/ml. Further 28 strains exacted utilization of concentration equal to 31.2 to 62.4 micrograms/ml while in case of the remaining 15 strains MBC values achieved the level of 62.5 to 125 micrograms/ml. Strains from Leptotrichia buccalis and then Gram--positive anaerobic bacteria were the most sensitive ones both to Sterinole and cetylpirydine chloride while Gram--negative anaerobic bacteria and anaerobic micrococcus were less sensitive.