Current status of nightguard vital bleaching

Indications for using a 10% carbamide peroxide material in a custom-fitted tray to whiten teeth include teeth discolored from aging, chromogenic foods and drinks, and smoking, and also brown fluorosis-stained teeth, single dark teeth, and tetracycline-stained teeth. Tetracycline-stains may require 2 to 6 months of nightly treatment, whereas after discolorations generally resolve in 2 to 6 weeks. After an initial relapse in the first 2 weeks after the end of treatment, color tends to be stable for 1 to 3 years, with some treatments being permanent. The ADA has approved only six 10% carbamide peroxide materials, which have extensive research and publications on safety and efficacy. Considering the average cost of $196 per arch, and the noninvasive nature of this treatment, nightguard vital bleaching is probably the safest, most cost-effective, patient-pleasing method to improve the appearance of a smile. However, it should be supervised by a dentist for the proper examination, diagnosis of the cause of discoloration, treatment options, and fabrication and fitting of the carrier. Sensitivity during whitening may be treated with fluoride and potassium nitrate.

Bleaching primary teeth with 10% carbamide peroxide

Bleaching teeth with 10% carbamide peroxide in a custom-fitted tray has been popular for more than 10 years. However, primary teeth are seldom considered for bleaching due to the need for compliance by the child and the natural whiteness of the primary teeth. This report describes an indication-teeth darkened from trauma-as well as the technique and outcome for bleaching discolored primary teeth.

Tray delivery of potassium nitrate-fluoride to reduce bleaching sensitivity

OBJECTIVE

Tooth sensitivity is a common side effect associated with tooth whitening. The purpose of this study was to determine if bleaching tray delivery of potassium nitrate-fluoride reduces bleaching sensitivity enough to allow continuation of whitening treatment.

METHOD AND MATERIALS

Thirty patients were enrolled in a university-approved clinical study and had their teeth bleached at night with 10% carbamide peroxide in a custom-fitted tray. The bleaching tray was a rigid experimental design for which sensitivity was expected. If tooth sensitivity was experienced, the patient applied a gel containing 5% potassium nitrate and 1,000 ppm sodium fluoride in the bleaching tray for various time periods. Log forms were collected upon completion of bleaching, and patient interviews were used to compare effects of the gel before and after sensitivity treatment.

RESULTS

Sixteen out of 30 patients experienced tooth sensitivity. Of those 16 patients, 12 used the gel, and 11 of the 12 reported a reduction in sensitivity. Treatment times ranged from 10 minutes before bleaching to 30 minutes before and after. The number of applications ranged from one to continuous use. Some patients were able to continue bleaching after one gel application with no subsequent sensitivity. Other patients were unable to continue bleaching unless they continued using the gel. The incidence of tooth sensitivity (53%) reported in this study is consistent with sensitivity reported in studies using semi-rigid custom-fitted trays made from stone casts with a nonscalloped, nonreservoir design.

CONCLUSION

The use of a 5% potassium nitrate-fluoride gel applied in the tray as needed for tooth sensitivity associated with nightguard vital bleaching can reduce sensitivity in a majority of patients and allow most patients to continue bleaching to completion.

Nightguard vital bleaching of tetracycline-stained teeth: 54 months post treatment

PURPOSE

The purpose of this longitudinal whitening study was to determine the stability, post-treatment side effects, and patient satisfaction after 6 months of active treatment of tetracycline-stained teeth with 10% carbamide peroxide at 0 and 54 months post treatment.

MATERIALS AND METHODS

Twelve patients who completed the study (80%) were contacted and asked to participate in a survey concerning their whitening experience. Subjects were asked whether there had been any change in the shade of their teeth after treatment, and if they had experienced any side effects that they believed were treatment-related. Eight of the twelve patients underwent clinical examination.

RESULTS

Ten patients (83%) reported no obvious shade change or only a slight darkening not noticed by others. Two (17%) reported a slight darkening that is probably noticeable by other people, but no one reported moderate darkening or significant darkening back to original shade. All respondents (n = 12) denied having to have a crown or root canal that they believed was treatment-related. Examiners who compared preoperative and post-treatment photographs and Vita shade values were in agreement with the patient's perceptions of shade change. The degree of improvement was significant for both the immediate (0 mo) and the 54-month post-treatment comparison with the pretreatment shade (p < .005 and p < .01 respectively).

CLINICAL SIGNIFICANCE

Results of this nightguard vital bleaching study indicate that tetracycline-stained teeth can be whitened successfully using extended treatment time, and that shade stability may last at least 54 months after treatment. Patients who participated in this study were overwhelmingly positive about the procedure in terms of shade retention and lack of post-treatment side effects.

Teaching nightguard bleaching and other tooth-whitening procedures in North American dental schools

Tooth-whitening using carbamide peroxide delivered in a custom-fitted tray (nightguard bleaching) is a relatively new procedure, yet it is currently one of the most commonly used types of esthetic dental treatment in private practice. This study determined the extent that nightguard bleaching (NGB) has been included in dental school curricula. All sixty-five dental schools in North America were surveyed about curriculum content and treatment protocol for the use of nightguard and other bleaching procedures, generating an 82 percent response. The survey covered eighteen subject areas related to NGB ranging from clinical requirements and indications to products and recall intervals used. The most commonly taught tooth-whitening procedure was NGB, which was most often taught by operative and restorative faculty. Although no schools had clinical requirements for NGB, 92 percent taught it. The most common indications for NGB were esthetic shade change and pre-restorative lightening of teeth. Unrestored caries, defective restorations, and pre-existing sensitivity were common contraindications. Most schools do not use a specific NGB consent form, but most use written patient instructions. Most schools use at least two different NGB products, bleach for two to four weeks, and use reservoired and scalloped trays. An average of 25 percent of NGB patients were estimated to develop sensitivity, for which treatment recommendations include fluoride, desensitizing toothpaste, and reduced exposure time. Curriculum time and safety concerns were reasons for not teaching NGB (8 percent schools). Most schools indicated that the relative importance of NGB in the curriculum was increasing.

Bleaching and temporomandibular disorder using a half tray design: a clinical report

A maxillary soft, custom-fitted tray was fabricated for a patient to perform nightguard vital bleaching. Treatment was interrupted after the patient experienced pain in the temporomandibular joint area shortly after wearing the bleaching prosthesis. The tray was trimmed so the labial, incisal and buccal cusps were covered and Sc) the patient had complete tooth-to-tooth contact in the maximum intercuspal position. The prosthesis proved to be retentive even without the presence of the bleaching material. The thick, sticky bleaching material was contained in the half tray design and the tray was held in place. The patient was able to continue the bleaching process for the 2-week duration necessary to achieve successful lightening of the teeth without further TMD symptoms.

Nightguard vital bleaching beneath existing porcelain veneers: a case report

Dentist-prescribed, at-home bleaching with 10% carbamide peroxide was used to lighten the apparent color of teeth with preexisting porcelain veneers. Veneers had been placed over unprepared, tetracycline-stained teeth; the translucency of the veneers over the discolored teeth resulted in a graying of the veneers. A custom-fitted tray with no reservoirs and no gingival scalloping was fabricated. A 10% carbamide peroxide material was applied nightly for 9 months to achieve the maximum change in the underlying tooth color. The patient was pleased with the apparent color change. Tooth sensitivity during treatment was minimal (lasting 4 days total); the patient treated sensitivity by brushing with a potassium nitrate-containing toothpaste or applying fluoride in the tray.

Efficacy of nightguard vital bleaching technique beyond the borders of a shortened tray

PURPOSE

The purpose of this study was to determine if bleaching extends beyond the borders of a shortened tray or if a demarcation line is found.

MATERIALS AND METHODS

Fifteen extracted teeth were selected darker than B2 on a Vita Lumin Shade guide (Vita Lumin, Bad Sackingen, Germany). The teeth were mounted in arch-like fashion in dental stone. Alginate impressions were made, and a stone replica of the four arches of teeth was generated. Vacuum-formed bleaching trays were fabricated for each arch, without and with reservoirs, as per the product to be tested. The nonreservoir trays were trimmed to one half the clinical crown length, and the reservoir trays were trimmed 1 mm beyond the border of the half-length reservoir. Measurements were taken from the cementoenamel junction (CEJ) to the tray border for each tooth. The trays averaged 5.1 mm short of the CEJ. The reservoir group was treated with viscous glycerin-based 10% carbamide peroxide (Opalescence, Ultradent Products Inc., South Jordan, Utah); the nonreservoir group with creamy dentifrice-based 10% carbamide peroxide (Platinum, Colgate Oral Pharmaceuticals, Canton, Massachusetts). The trays were loaded and fully seated on the teeth. Excess bleaching material was removed with a toothbrush and water rinse. Each assembly was placed in a humidor with incisal edges down to simulate oral conditions. The process was repeated for fourteen 6- to 8-hour bleaching sessions. Blinded and nonblinded operators determined post-bleaching shades, with consensus reached on differing shades.

RESULTS

All teeth demonstrated lightening of 1 to 10 (mean 5.2) increments on the value-oriented shade guide. The bleaching effect extended beyond the tray and no demarcation lines were noted on any of the teeth.

CLINICAL SIGNIFICANCE

This in vitro study suggests that successful bleaching occurs beyond the borders of inadvertently shortened trays. The clinician does not necessarily need to remake the tray if the tray does not cover all portions of the tooth.

Assessing dentin color changes from nightguard vital bleaching

BACKGROUND

At-home bleaching with 10 percent carbamide peroxide in a custom-fitted tray has been reported to change the color of dentin. The purpose of this study was to validate the color change of dentin and to determine whether the color change was uniform or occurred from the outside (the dentinoenamel junction) to the inside (the pulpal wall).

METHODS

The authors sectioned 10 extracted human teeth incisogingivally through the midfacial long axis, and sealed their cut surface against glass microscope slides. Identifying marks were placed on the glass over the tooth sections to serve as a color control and in the dentinal areas closest to the dentinoenamel junction and the pulpal wall. Teeth were bleached for 10 days with 10 percent carbamide peroxide. Photographs were taken from the glass-covered side of the teeth, digitized and converted to gray-scale levels (consisting of 256 shades of gray ranging from black to white). Marked areas were measured with a National Institutes of Health Image software program and analyzed statistically for changes in lightness between the control marks and the inner and outer dentinal marks over time.

RESULTS

Paired t-tests and analysis of variance indicated a significant increase in lightness (P = .01) for the inner and outer dentinal areas during bleaching compared with the control areas. No significant differences were found in the rate of change for the inner and outer dentinal areas (P = .89).

CONCLUSIONS

The increase in lightness confirms that a significant color change occurred in the dentin during bleaching with 10 percent carbamide peroxide. This change occurred throughout the dentin at a uniform rate, rather than from the outside inward.

CLINICAL IMPLICATIONS

The results of this study show that at-home bleaching with 10 percent carbamide peroxide can change the color of dentin, which is important to treat intrinsic stains from tetracycline treatment, trauma and aging or inherited discolorations. The bleaching material easily penetrates the tooth to change the dentin color at the same rate throughout, indicating that the type of stain may be the important factor in determining bleaching success.

The current status of vital tooth whitening techniques

Tooth whitening of vital teeth continues to have a major impact on the practice of dentistry. The growing public interest in having whiter, brighter teeth is clearly evident in the advertisements from toothpaste manufacturers on "whitening" formulations of their products and by the number of individuals seeking whitening procedures from their dentists. In addition, new over-the-counter whitening products continue to emerge in a marketplace that cannot seem to get teeth white enough, bright enough, fast enough. What new products and procedures have evolved over the past decade to whiten teeth? Are they better, safer, faster, and more effective now? Are dentists meeting public demand for whiter teeth and is this quest having a positive or negative impact on the practice of dentistry or the patient's dental health? I posed these questions to a group of experts on whitening procedures to get their opinions and recommendations.

Carbamide peroxide whitening of nonvital single discolored teeth: case reports

Patients who present with a single discolored tooth represent a significant restorative challenge. These case reports describe an economic and conservative treatment option for these patients. The situations presented demonstrate techniques for bleaching with carbamide peroxide in a traditional nightguard or with an inside-outside technique to achieve acceptable esthetic results on isolated nonvital discolored teeth. Although these techniques may not be effective in all cases, they do not compromise or eliminate any future treatment options.

Simultaneous bleaching of vital teeth and an open-chamber nonvital tooth with 10% carbamide peroxide

OBJECTIVE

The purpose of this study was to evaluate the effectiveness of bleaching a nonvital tooth with an open pulp chamber while simultaneously bleaching the other vital teeth with 10% carbamide peroxide.

METHOD AND MATERIALS

Ten discolored nonvital teeth were treated. Each nonvital tooth was prepared as in the conventional "walking bleaching" fashion, so that the gutta-percha was sealed from the pulp chamber. The 10% carbamide peroxide was injected into the chamber of the nonvital tooth and loaded into the custom-fitted tray for all teeth. The nonvital teeth were bleached from both the inside and the outside. The patient closed the orifice with a cotton pellet during the day and changed the cotton pellet after meals. The patient applied fresh solution nightly.

RESULTS

All teeth were successfully lightened. The time required to lighten the nonvital tooth was related to the duration of the discoloration.

CONCLUSION

With proper patient selection and education, this technique can provide an effective way to lighten nonvital and vital teeth simultaneously, especially where extended treatment time may be required for difficult discolorations.

Use of different concentrations of carbamide peroxide for bleaching teeth: an in vitro study

OBJECTIVE

This in vitro study compared the shade changes in extracted teeth during 2 weeks' whitening with 5%, 10%, or 16% carbamide peroxide.

METHOD AND MATERIALS

After color calibration, the sole examiner selected 110 extracted unrestored, noncarious teeth, shade A3 or darker on a value-oriented guide. The teeth were randomly distributed into equal color groups. The control group (11 teeth) was treated with 0.9% saline, while the experimental groups (33 teeth each) were treated with 5%, 10%, or 16% carbamide peroxide. The solutions remained on the teeth for 8 hours. The teeth and tray were rinsed with tap water for 2 minutes, then rehydrated in 0.9% saline for 16 hours in the humidifier. The shade was assessed, and the process was repeated daily for 2 weeks.

RESULTS

Repeated-measures analysis of variance indicated a significant difference in overall shade values between the control and all carbamide peroxide-treated groups at days 8 and 15. A Kaplan-Meier Survival Analysis indicated a quicker two-tab color change for the 10% and 16% groups than the 5% group. However, continuation of the 5% treatment to 3 weeks resulted in shades that approached the 2-week 10% and 16% values.

CONCLUSION

Lower concentrations of carbamide peroxide take longer to whitening teeth but eventually achieve the same result as higher concentrations. Higher concentrations may cause increased sensitivity.

Vital tooth bleaching with Nightguard vital bleaching

Between July 1994 and May 1996, several landmark articles were published concerning the safety and efficacy of vital tooth bleaching with 10% carbamide peroxide in a customfitted tray. The American Dental Association (ADA) published guidelines for ADA acceptance, and three products received approval. Long-term clinical trials on 38 patients indicated 92% successful bleaching after 6 weeks of treatment. Results were stable in 74% of the patients at 1.5 years, and in 62% of the patients at 3-year follow-up with no further treatment. Clinical pulpal studies and periodontal studies indicated no detrimental safety problems, although some laboratory cell studies suggested concerns. The noncarcinogenic potential of 10% carbamide peroxide was established in animal studies. Successful bleaching of tetracycline-stained teeth was achieved after 6 months of treatment, with no tooth problems detected clinically or by scanning electron micrograph. Extended treatment times are effective on other stains from dentinogenesis imperfecta or nicotine. On insertion in the mouth, 10% carbamide peroxide elevated the pH in the tray and saliva. After 4 hours of clinical wear, over 60% of the newer, thicker materials (Opalescence [Ultraclent Products, South Jordon, UT] and Platinum [Colgate Oral Pharmaceuticals, Canton, MA]) was present and active in the tray. Nightguard vital bleaching seems to be the most cost-efficient, user-friendly, patient-accepted method of bleaching teeth available to the profession and is safe and effective. Over-the-counter products can have harmful effects on tooth structure and may not lighten teeth.

Nightguard vital bleaching removes brown discoloration for 7 years: a case report

Nightguard vital bleaching with 10% carbamide peroxide was used to remove a brown stain from the maxillary central incisor of a 13-year-old-boy. After 7 years, during which there was no touch-up treatment, the discoloration had not returned. This conservative technique should be considered before more invasive procedures for the treatment of discolored vital teeth in young patients.

Dental practices that aid the general practitioner and forensic dentist

There are practices that improve the efficiency of a general dentistry office and may aid a forensic dentist in making an identification. These practices include maintaining current dental charts, using the accepted post-mortem charting nomenclature, and maintaining quality radiographs as well as complete and legible progress notes.

Using double-poured alginate impressions to fabricate bleaching trays

Esthetic and diagnostic treatment often requires two casts of one arch, one for baseline and one for alterations (diagnostic wax-up, bleaching tray, occlusal analysis). The purpose of this study was to compare the accuracy of stone casts generated from a second pour of a properly handled alginate impression with first-poured casts. A maxillary dentoform was indexed with six reference spaces (#8-15, 9-2, 2-15, and incisal-to-gingival of #3, 9, 14). Irreversible hydrocolloid (Jeltrate) impressions were made in perforated steel trays by a single investigator. Impression material was spatulated for 1 minute. The seated impression and dentoform were wrapped in a damp paper towel to simulate intraoral conditions, and allowed to set for 2 minutes. Upon separation, the impression was stored in a damp towel for 5 minutes. The impression was poured in cast stone (Microstone) according to the manufacturer's instructions. The stone-filled impression was immediately rewrapped in a damp paper towel and allowed to set for 45 minutes at room temperature. Upon removal of the stone, the impression was rinsed with cold water, shaken dry, and repoured in the same manner. Ten impressions were made: the first five impressions were poured to make casts for Group A, then repoured as described above for casts for Group B. The remaining five impressions were poured once to make casts for Group C. The six spaces of each cast were measured three times in random order using a dial caliper and the space average calculated for the cast. At each space, analysis of variance showed no significant difference among Groups A, B, or C (P < 0.05). When alginate impressions that have been poured with cast stone are kept moist during stone setting and repoured within 45 minutes, two casts can be generated from one impression with the same degree of accuracy as two casts made from taking two separate impressions, providing the alginate does not tear during first cast removal.

Risk factors for developing tooth sensitivity and gingival irritation associated with nightguard vital bleaching

The purpose of this study was to determine risk factors in the development of tooth sensitivity and gingival irritation associated with the nightguard vital bleaching technique. The potential risk factors evaluated (sex, age, reported allergy, whitening solution, number of times the solution was changed daily [its usage pattern], and dental arch) were collected from the daily log form turned in by each of the 64 participants after completion of the 6-week lightening process. Also evaluated for each participant, from color slides, were tooth characteristics such as gingival recession, defective restorations, abfraction lesions, enamel-cementum abrasion, etc, and reported side effects. The generalized Mantel-Haenszel statistic was used to assess the association between the potential risk factors and the development of tooth sensitivity and/or gingival irritation. No statistical relationship existed between age, sex, allergy, tooth characteristics, or the dental arch lightened and the development of side effects. Initially, a statistically significant association existed between side effects and the whitening solution used. However, when the analysis was controlled for usage pattern, this relationship disappeared. Patients who changed the whitening solution more than once a day reported statistically significantly more side effects than did those who did not change the whitening solution during their usage time.

Effect of 10 percent carbamide peroxide on color of provisional restoration materials

To improve esthetic results, nightguard vital bleaching of teeth using 10 percent carbamide peroxide, or CP, may be indicated when an anterior tooth is restored with a provisional crown. This study evaluated the effect of NGVB solutions containing 10 percent CP on the color stability of provisional restoration materials. Disks were fabricated from six representative provisional restoration materials and were tested in five different 10 percent CP bleaching agents. An orange discoloration occurred with provisional materials that contained methacrylate when they were exposed to 10 percent CP bleaching solutions.

Historical development of whiteners: clinical safety and efficacy

Since the introduction in 1989 of a home tooth-bleaching technique, the practice has become widespread in the USA. Safety concerns led the Food and Drug Administration (FDA) to temporarily ban sales in 1991 but the ban was later lifted, and the American Dental Association (ADA) now issues guidelines for safety and efficacy. Early information on safety of home bleaching products was often skewed because they were being compared out of context with those designed to be used only in the dental office. The early studies also failed to put the risks into perspective with the risks from other routine dental procedures. The risks are minimized with the systems supplied by dentists because he or she is able to diagnose any problems or special needs, to plan appropriate treatment and to fabricate, fit and adjust the prosthesis used to apply the material. A wide variety of disfigurements may now be treated successfully at home using preparations supplied by the dental practitioner.

Nightguard vital bleaching: current concepts and research

Nightguard vital bleaching, or NGVB, which involves the use of a 10 percent carbamide peroxide in a custom-fitted mouthguard, has been used with much success since its introduction in 1989. Normal bleaching treatment time is one to two weeks, although times may be extended to months for difficult stains. When used in a professionally supervised manner, nightguard vital bleaching is as safe as any other routinely used dental treatment.

Demineralization effects of 10 percent carbamide peroxide

OBJECTIVES

The purpose of this in vitro study was to measure the amount of calcium lost from enamel exposed to a 10% carbamide peroxide solution.

METHODS

Nine teeth (3 incisors, 2 premolars, 4 molars) were sectioned to serve as paired test and control specimens. Each tooth half was coated with wax, leaving a uniform 3 mm x 4 mm window of exposed enamel. Test specimens were placed in culture tubes with 1.00 ml of deionized water and 0.02 ml of 10% carbamide peroxide for 6 h; controls were exposed to water alone. Calcium concentrations in the solutions were measured using a Perkin-Elmer 5100 atomic absorption spectrophotometer.

RESULTS

Teeth exposed to carbamide peroxide lost an average of 1.06 micrograms/mm2 of calcium. This amount of loss was significantly greater than controls (p < 0.001), according to ANOVA. For comparison, teeth were exposed to a cola beverage for 2.5 min, the time equivalent of drinking a 16 oz. beverage. The amount of calcium lost from these teeth was also about 1 microgram/mm2.

CONCLUSIONS

Teeth exposed to 10% carbamide peroxide lost calcium. However, the amount of loss was small, and may not be clinically significant.

Assessing the effects of 10 percent carbamide peroxide on oral soft tissues

To examine the effects of a 10 percent carbamide peroxide bleaching gel on the oral soft tissues, the authors conducted a prospective, double-blind, placebo-controlled clinical investigation. Fifty-two patients completed a two-week treatment regimen, applying either a placebo or a 10 percent carbamide peroxide gel in a soft tray for eight hours a day. Clinicians examined the participants' oral soft tissues at baseline and one week, two weeks and six weeks after the first treatment. The examiners recorded the Silness and Löe plaque and gingival indexes, nonmarginal gingival index and nongingival oral mucosal index at each examination. The data collected at these intervals did not indicate that any soft tissue damage had occurred as a result of the bleaching regimen.

Commonly asked questions about nightguard vital bleaching

There are three basic classes of materials and techniques used for the bleaching of vital teeth. These include the in-office bleaching technique with 35 percent hydrogen peroxide, the Nightguard vital bleaching technique with 10 percent carbamide peroxide, and the over-the counter bleaching kits with three-to-six percent hydrogen peroxide. The most popular of these techniques is Nightguard vital bleaching also referred to as dentist-prescribed, home-applied bleaching. This article looks at the current status of the Nightguard vital bleaching technique, with a special emphasis on the clinical aspects of the treatment, along with the most commonly asked questions concerning the procedure. It would still appear that this form of dentist-prescribed, home-applied bleaching, when preceded by a proper examination and correct diagnosis, applied with a properly fitted prosthesis, and monitored as needed by a dentist, is as safe as other accepted dental procedures or commonly ingested foodstuffs.

Change in pH of plaque and 10% carbamide peroxide solution during nightguard vital bleaching treatment

The purpose of this study was to evaluate in vivo changes in the pH of plaque and of a 10% carbamide peroxide solution occurring within the bleaching guard during a 2-hour nightguard vital bleaching procedure. Baseline pH values for plaque and the carbamide peroxide solution were established. A small hole was placed in the anterior interproximal region of the guard to allow placement of the pH electrode. The pH of the carbamide peroxide solution was measured at 5-minute intervals. After 2 hours, the guard was removed and pH of the plaque was remeasured. The procedure was repeated three times on each of four subjects. The mean baseline pH reading for plaque was 6.31 and mean final pH reading was 6.86. The difference was statistically significant. At initial placement of the carbamide peroxide-filled guard, the mean intraguard pH was 4.50 (range of 2.80 to 7.80). The mean peak intraguard pH of 8.06 (range of 7.30 to 8.43), which was significantly different from baseline, was obtained within 31 minutes. The pH of plaque, saliva, and a 10% carbamide peroxide bleaching solution within the guard increased significantly during bleaching and remained significantly elevated for the duration of the study (2 hours).

Effectiveness, side effects and long-term status of nightguard vital bleaching

In this clinical trial of nightguard vital bleaching for six weeks, 92 percent of the patients experienced some lightening of treated teeth. About 97 percent of patients with teeth stained through aging, inherent discoloration, brown fluorosis or trauma experienced lightening, as did 75 percent with tetracycline-stained teeth. Sixty-six percent experienced side effects, which resolved in 24 to 48 hours. Earliest re-treatment was done after one year in less time. Minimal color change occurred for 74 percent after 1 1/2 years and 62 percent after three years.

Salivary pH changes during 10% carbamide peroxide bleaching

The purpose of this study was to evaluate the effect on salivary pH of a 10% carbamide peroxide solution when used with a custom-fitted guard for bleaching teeth. Baseline pH values were established for unstimulated saliva and on saliva produced while wearing an empty guard. After insertion of a guard half filled with Proxigel, salivary pH measurements were made at 5-minute intervals until the values returned to baseline levels. Mean salivary pH values were 6.81 +/- 0.11 for unstimulated samples and 6.91 +/- 0.18 after insertion of the empty guard. After insertion of the filled guard, there was a statistically insignificant decrease in salivary pH during the first 5 minutes, followed by an increase above baseline at 10 minutes, to a mean peak value of 7.32 +/- 0.27 at 15 minutes. The difference between the baseline values and the mean peak value at 15 minutes was statistically significant. The results of the study indicated that the pH of saliva increased significantly during the first 15 minutes of nightguard vital bleaching and did not significantly drop below baseline in the first 2 hours after insertion with a moderately low-pH solution.

Toxicity of two carbamide peroxide products used in nightguard vital bleaching

This study evaluated the effects of two generic classes of 10% carbamide-peroxide (CP) oxygenating agents (currently under clinical assessment for nightguard vital tooth bleaching) for lethality and genetic mutation after oral administration to mice, and for cellular cytotoxicity to mouse fibroblasts in vitro. The single dose LD50 values for a non-carbopol-containing CP (Gly-Oxide) and a carbopol-containing CP (Proxigel) in mice were found to be 143.8 mg/kg and 87.2 mg/kg, respectively. Genotoxicity, as measured by the Mouse Micronucleus test for mutagenicity, was negative for both 10% CP agents in comparison with positive and negative controls. Cytotoxicity as measured in the L929 fibroblast lysis assay resulted in 50% killing of L929 fibroblasts at 0.62 for the non-carbopol-containing CP and 1.88 mmol/L for the carbopol-containing CP. Both 10% CP agents were compared with seven widely-used dental products in the L929 fibroblast lysis assay and found to be no more toxic than these products.

Efficacy of foam liner in 10% carbamide peroxide bleaching technique

The purpose of this study was to determine if the use of a foam liner in a tray during the nightguard vital bleaching technique would cause a difference in the rate of bleaching or the final shade of the bleached teeth. Ten subjects were selected who had previously successfully bleached their maxillary arch by using a 10% carbamide peroxide solution. Vacuum-formed guards were fabricated for the mandibular arch so that one quadrant was covered with a conventional-style guard, and the other quadrant was covered with a foam-lined guard. All patients were successful in bleaching their mandibular arch. No patient reported any difference between the two quadrants in the rate of bleaching or in the final shade, nor was any difference apparent to the operators clinically or in photographic evaluation. It appears that the addition of a foam insert does not noticeably alter the clinical result of home bleaching. If bleaching is successful in one arch, it can be expected to be effective in the other arch.

Commonly asked questions about nightguard vital bleaching

There are three basic classes of materials and techniques used for the bleaching of vital teeth. These include the in-office bleaching technique with 35 percent hydrogen peroxide, the Nightguard vital bleaching technique with 10 percent carbamide peroxide, and the over-the-counter bleaching kits with three-to-six percent hydrogen peroxide. The most popular of these techniques is Nightguard vital bleaching, also referred to as dentist-prescribed, home-applied bleaching. This article looks at the current status of the Nightguard vital bleaching technique, with a special emphasis on the clinical aspects of the treatment, along with the most commonly asked questions concerning the procedure. It would still appear than this form of dentist-prescribed, home-applied bleaching, when preceded by a proper examination and correct diagnosis, applied with a properly fitted prosthesis, and monitored as needed by a dentist, is as safe as other accepted dental procedures or commonly ingested foodstuffs.

History, safety, and effectiveness of current bleaching techniques and applications of the nightguard vital bleaching technique

This article reviews the literature on the use of hydrogen peroxide in three professionally administered bleaching techniques from historical, technique, and safety viewpoints. Safety over time, absolute safety, and relative safety of nonvital bleaching, in-office vital bleaching, nightguard vital bleaching, and over-the-counter bleaching kits are compared. The advantages and disadvantages of different bleaching options, as well as indications for individual or combined use of the techniques, are discussed. In addition, specific indications for the use of the nightguard vital bleaching technique are presented.

Bleaching of vital and nonvital teeth

Although tooth bleaching has been known to the dental profession for over 100 years, new knowledge is continually surfacing. This review discusses the 1990 to 1991 literature on two nonvital bleaching techniques (thermocatalytic and walking) and three classes of vital bleaching techniques (in-office; dentist-prescribed, home-applied; and over-the-counter kits). The choice for nonvital bleaching is the walking bleach technique, with the use of sodium perborate alone having less potential for cervical resorption. The choices for vital bleaching techniques are either the dentist-prescribed, home-applied technique, the in-office technique, or a combination of the two. Bonding should be delayed 2 weeks after bleaching. Microabrasion is a possible second choice for certain discolorations. These chosen bleaching techniques, when used in a professionally appropriate manner, seem as safe as other commonly used dental treatments.

Overview and status of mouthguard bleaching

Since the bleaching of vital teeth using a tray delivery system with a 10 percent carbamide peroxide first became common knowledge in March, 1989, there has been much discussion, improvement, and questions concerning the process and the various products available. This article presents an overview of its history, the variations in techniques, and questions concerning safety, including the impact on tooth structure, the pulp, soft tissue of the mouth, and systemic ingestion. It divides currently available products according to their composition, into either a carbamide peroxide with and without carbopol, a hydrogen peroxide of varying concentrations, a hydrochloric acid, or other categories. It discusses the various delivery mechanisms and comments on their apparent effectiveness, as well as reflecting the current knowledge base of the profession.

Nightguard vital bleaching: how safe is it?

The conservative technique for bleaching vital teeth using a nightguard and a 10% carbamide peroxide solution has captured the esthetic interests of the dental profession. The purpose of this article is to assess the safety of the products used in this bleaching technique based on results from past related research and current research. Ten percent carbamide peroxide solutions used in numerous studies have demonstrated tissue-healing properties as well as a propensity for the reduction of plaque and gingivitis. None of these clinical studies revealed any untoward or detrimental side effects, and all demonstrated beneficial effects. Although some concern exists regarding the potentiating effects of peroxide solutions in the presence of known carcinogens, concerns of toxicity or damage to hard and soft tissues appear unfounded. The majority of current and past research and literature indicates that the current use of a 10% carbamide peroxide solution in the method advocated for bleaching vital teeth is apparently safe when administered properly under the supervision of a dentist.

Nightguard vital bleaching: effects on enamel surface texture and diffusion

A recently reported technique for bleaching vital discolored teeth involves the use of a mouthguard and 10% carbamide peroxide without preoperative etching or postoperative polishing of the enamel. This in vitro study evaluated the effects of the bleaching agent on the surface texture of the enamel. Thirty-three extracted teeth were subjected to 10% carbamide peroxide for a period equivalent to 5 weeks of nighttime wear. A control area on each tooth had been covered and sealed. All discolored teeth experienced lightening, but there was no difference in color between the treated and control areas; the color-changing effects apparently extend to portions of the tooth not in direct contact with the solution. Epoxy replicas of the teeth were examined under a scanning electron microscope. No etching was apparent, and no difference in surface texture between treated and control areas was detected.

Thermal removal of composite resin: effect on rebonding etched metal

If a correctly etched-metal, resin-bonded fixed partial denture debonds, one recommendation for reuse is to clean the prosthesis by oven burnout, then to recement it without reetching. The purpose of this study was to determine whether the tensile strength of the bond of composite resin cement to either electrolytically or chemically etched metal was affected by earlier removal of residual resin with a burnout procedure. Pairs of rods made of nickel-chromium-beryllium were electrolytically or chemically etched according to accepted techniques, then bonded end-to-end with an enamel bonding agent and composite resin cement in an alignment apparatus. The rods were stored for 24 hours in 37 degrees C water, then debonded to determine the tensile bond strengths in megapascals. After debonding, the rods were placed in the burnout oven at 510 degrees C for 30 minutes. The rods were then ultrasonically cleaned in ethyl alcohol for 6 minutes. The pairs were rinsed under running water and then rebonded and debonded nine more times under the same conditions. A linear regression analysis revealed that there was no statistically significant difference (p less than 0.05) in the tensile strength of the bonds after repeated thermal cleanings and bondings. Correctly etched metal, resin-bonded fixed partial dentures may be recemented without re-etching after thermal cleaning without a statistically significant loss in the tensile strength of the bonds.

Placement of cast restorations over direct pulp capping procedures: a decision analytic approach

A review of the literature shows a significant amount of controversy regarding the success of pulp capping procedures, with the average clinically evaluated pulp capping success being 81%, and 75% when evaluated histologically. This study evaluated the costs and benefits of a pulp cap versus endodontic therapy for a tooth that is to receive a cast restoration, and determined what level of success is needed for pulp capping to be the preferred treatment.

Effects of water, speed, and experimental instrumentation on finishing and polishing porcelain intra-orally

Previous studies indicated that porcelain can be polished smoother than glazed porcelain with instruments suitable for intra-oral use. This study evaluated several experimental instruments and materials to determine if polishing could be done more efficiently. Scanning electron microscopy was used to evaluate the surface texture produced by different combinations of experimental instruments applied with high and moderate speed, wet and dry, to porcelain disks. No sequence matched the polished standard. However, the optimum surface texture was obtained with diamond instruments (with progressively smaller particle sizes) used at a moderate speed with water, followed by a 30-fluted carbide bur at high speed and dry, then diamond polishing paste on a webbed rubber cup. In all polishing sequences tested, the best results were obtained with each individual instrument when diamond instruments were used at moderate speed wet, and when carbide instruments were used at high speed dry.