Effect of smear layer removal on bleaching of human teeth in vitro

The purpose of this study was to evaluate objectively in vitro the effectiveness of bleaching artificially discolored teeth with or without the smear layer present using sodium perborate mixed with sterile water or 35% hydrogen peroxide (H2O2). Seventy fully developed maxillary anterior teeth were artificially stained with human hemoglobin and separated into one control and four experimental groups. After the smear layer was removed on half the experimental teeth and left intact on the other half, all of the teeth were bleached intracoronally with sodium perborate and 35% H2O2 or sodium perborate plus water. The bleaching agents were applied twice over a 6-day period. The changes in tooth shade were objectively analyzed using a SP78 sphere spectrophotometer at 1, 30, and 60 days postbleaching. The presence or absence of the smear layer did not significantly influence the outcome of bleaching (p > 0.05). The teeth bleached with sodium perborate and 35% H2O2 were significantly lighter than the teeth bleached with sodium perborate and sterile water (p < 0.0001) at each experimental period. Based on the findings of this study, it is not advantageous to remove the smear layer before intracoronal bleaching.

Combining treatment modalities for tetracycline-discolored teeth

Tetracycline-discolored teeth that are to be restored by porcelain laminate veneers present a clinical challenge. Successfully bleaching such teeth prior to veneering will permit the clinician and technician to overcome the technical difficulties associated with masking dark teeth. This article describes a combined treatment modality in which the teeth are bleached after the preparation for porcelain laminate veneers.

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.

Long-term prognosis of intentional endodontics and internal bleaching of tetracycline-stained teeth

A total of 112 severely tetracycline-stained teeth in 20 patients were treated by endodontics and nonthermal internal bleaching. All teeth were healthy, intact, and had no history of trauma. The patients were monitored for 5 to 15 years. Excellent, permanent esthetic results were obtained with no side effects. The quality of endodontic treatment and lingual access restoration were important factors in the longevity of the bleaching results.

Laser tooth whitening

Cosmetic and adhesive dentistry has not only increased patients' self-esteem and confidence, it has increased their awareness of the value of healthy teeth and gums. White teeth have always been a high priority with patients. Creating and maintaining white teeth, however, has not always been easily achieved. The recent development of laser-assisted tooth whitening procedures makes it easier, faster, non-invasive, and affordable for patients to have whiter teeth.

Nightguard vital bleaching: a review and clinical study

Based on current clinical experience and research, dentist-prescribed home bleaching, also referred to as nightguard vital bleaching, is a safe and effective technique for whitening teeth when a carbamide peroxide material (up to 10 percent) is used. The bleaching material should be produced by a recognised and reputable manufacturer and must be used under a dentist's supervision over a relatively short time. Mild thermal sensitivity is a common side effect; however, no long-term pulpal effects have been shown. The reduction in the bond strength of resin to freshly bleached enamel and dentine has been shown to be transient, and no clinically significant changes in surface morphology or physical properties have been shown to occur to teeth or dental restorative materials as a result of vital bleaching. As a consequence, vital bleaching has gained favour with patients and dentists alike. Significant benefit was obtained in 12 subjects using two nightguard bleaching systems which were equally effective.

Dimensional changes during veneering procedures on discoloured teeth

OBJECTIVES

The aim of the study was to determine the dimensional changes of teeth when veneering procedures are involved.

METHODS

Fifteen discoloured central incisors were selected from a group of 180 veneer restorations (VRs) composed of three different types of materials (direct resin composite, indirect resin composite and porcelain). Impressions and dies were made before treatment, after preparation and after placement and finishing the restoration. Contact stylus profilometry and subsequent analysis of the 3-D surface images provided quantitative data of the differences between the various treatment phases.

RESULTS

The preparation reduction was the most for indirect resin composite VRs and the least for direct resin composite VRs. All veneer restorations showed nearly the same thickness and dimensional change after treatment, except one, which resulted in an additional increase of volume of the tooth.

CONCLUSION

From the results of this study it is concluded that the dimensions of a discoloured tooth treated with a veneer restoration unintentionally increased, resulting in overcontour.

The efficacy and safety of a 10% carbamide peroxide bleaching gel

OBJECTIVE

A 6-month, double-blind study was undertaken to assess the efficacy and safety of a 10% carbamide peroxide gel designed for at-home tooth bleaching.

METHOD AND MATERIALS

Sixty patients were randomized into two equal subgroups balanced by age, gender, and oral health status. Shade guide measurements, color transparency photographs, and colorimeter readings were taken and evaluated at baseline and 1, 2, 3, 6, 12, and 24 weeks. The active phase of treatment lasted 14 days.

RESULTS

At 22 weeks postbleaching (week 24 of the study), patients receiving the active agent had a 14.1 rank order difference in the shade guide from baseline, and 66% had a clinically observable color change as determined by photographic assessment. They also had a measurable, statistically significant color change from baseline to 6 months of delta E* = 5.0. The tooth color of maxillary incisors stabilized at week 6 and maxillary canines at week 12. The mean color change lost from weeks 2 to 24 was 45% (in delta E*). Transient tissue and tooth sensitivity, noted in some patients, resolved after treatment was completed.

CONCLUSION

The product tested is an effective and safe tooth-whitening agent.

Enamel staining and hypoplasia due to multiple causes in a Nigerian adolescent: report of a case

The aim of this report is to discuss the effects of childhood drug ingestion and metabolic disturbances of ill health in childhood on the coloration, structure and therefore the aesthetics of permanent dentition. To illustrate this, the report presents a case of a 15 year old Nigerian girl with combined tetracycline staining and chronological enamel hypoplastic defects on her teeth. The relationship between the clinical appearance of her teeth and her childhood medical and drug history are analysed. The various treatment modalities available for the management of the dental anomalies are discussed along with the rationale for the treatment given. Strategies for the prevention of these conditions are emphasised.

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.

The applications and integration of at-home bleaching into private dental practice

Since the introduction of home bleaching, the "whitening" of teeth has become much more common. This article describes at-home bleaching and the integration of this new treatment modality into the private dental practice. Case reports of the use of bleaching with and without restorative dentistry are presented, as well as tips on patient education and the timing of therapy.

Nightguard bleaching to lighten a restored, nonvital discolored tooth

Traditional techniques to lighten discolored endodontically treated teeth have used bleaching materials that had to be applied and directly monitored by dentists. These bleaching techniques have been associated with cervical resorption in nonvital teeth, and the treatment outcome is often difficult to predict. This article describes the use of nightguard bleaching to obtain an esthetic result for a restored nonvital tooth that had been treated with limited success with traditional office-based bleaching procedures.

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.

Gateways to patient acceptance of cosmetic procedures

Many clinicians have the desire to incorporate cosmetic dentistry into their everyday office procedures. It is often challenging to gain patient acceptance for these procedures. This review explores a way in which two services, tooth whitening and chairside esthetic mockups, can be used to introduce patients to cosmetic dentistry, to educate patients, and to increase happiness in the office while providing worthwhile services.

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.

Removal of surface stains from enamel surfaces with at-home vital bleaching: a case report

Stone model casts of a patient's maxillary and mandibular arches were used to fabricate a clear, soft, vacuum-formed custom mouth guard that was scalloped to end 1.0 mm supragingivally. The patient was given prophylaxis and oral hygiene home care instruction, and instructions regarding the placement of an at-home bleaching gel into the mouth guard and the mouth guard into the mouth. The patient was asked to wear the mouth guard for two hours daily before bedtime for one week and to return to the clinic for evaluation. This protocol was followed for three weeks for each arch. At the end of the three weeks, the stains on the most affected teeth were reduced dramatically.

The skeleton buildup technique: a systematic approach to the three-dimensional control of shade and shape

Due to the limitations of current shade-matching systems, shade communication has proven inadequate. Techniques for the fabrication of porcelain crowns that match the natural definition must address numerous factors. While all-ceramic restorations are indicated for the rehabilitation of the anterior dentition, these modalities are problematic in the restoration of teeth with discolored substrates. This article presents a systematic procedure for the three-dimensional fabrication of porcelain restorations. Techniques for building porcelain and altering the translucency of ceramic cores are also presented.