NIGHTGUARD VITAL BLEACHING

Post-Treatment Effects, Longevity, and Long-Term Results

Ralph H. Leonard, Jr.

INTRODUCTION

In 1989, Haywood and Heymann published their landmark article describing a new and revolutionary technique for lightening extrinsically stained or discolored teeth. Originally termed Nightguard Vital Bleaching (NGVB), the treatment has also been referred to as tooth whitening, tooth bleaching, and dentist-prescribed, home-applied (DPHA) bleaching. As described in the Haywood and Heymann article, this innovative technique was performed under the supervision of a dentist with respect to tray fabrication, diagnosis of tooth discoloration, and so on, but was implemented by the patient, who applied the treatment solution at home. As word spread about the new technique, acceptance of this simple and effective process to lighten teeth was rapid among dental practitioners as well as patients seeking a simple and effective way to lighten discolored teeth (Christensen 1989, Albers 1991, Haywood 1992) (Figures 19.1–19.3) Thus, manufacturers of dental products saw the interest in and demand for tooth bleaching and soon developed products ranging from simple bleaching solutions to comprehensive bleaching systems. Along with these product lines came the investment of millions of dollars in advertising to enlighten the public about this technique. It was no surprise that NGVB became one of the most sought-after cosmetic dental procedures requested by the public.

As described by Haywood and Heymann, the original technique involved wearing a rigid, nonscalloped treatment tray without reservoirs for 6 weeks and using a medium-viscosity 10% carbamide peroxide treatment solution. The technique has undergone many modifications including changes in tray material and design, different active ingredient concentrations, addition of thickening agents for sustained release of the active ingredient, use of reservoirs, and adjustments in treatment times (Christensen 1989, Darnell and Moore 1990, Freedman 1990, Haywood 1990, Albers 1991, Christensen 1991, Garber et al. 1991, Haywood 1991a, Haywood 1991b, Haywood 1991c, Haywood 1992a, Haywood 1992b, Haywood et al. 1994, Haywood et al. 1997). In addition, a trayless system using strips as the treatment solution delivery mechanism was developed (Sagel et al. 2000).

The use of NGVB generally preceded what the literature was reporting, and patients were asking questions concerning efficacy, longevity, and safety. Early on, the literature did report NGVB as being effective in lightening extrinsically stained or discolored teeth, in many cases up to 98% lighter (Haywood and Heymann 1989, Darnell and Moore 1990, Albers 1991, Christensen 1991, Garber et al. 1991, Haywood 1991c, Haywood 1992a, Ouellet et al. 1992, Williams et al. 1992, Gegauff et al. 1993, Reinhardt et al. 1993, Haywood et al. 1994, Matis et al. 2002). It was also well documented that up to 67% of patients using this procedure were reporting side effects, primarily tooth sensitivity (TS) and/or gingival irritation (Freedman 1990, Haywood 1990, Haywood 1991c, Powell and Bates 1991, Cooper et al. 1992, Howard 1992, Ouellet et al. 1992, Scherer et al. 1992a, Scherer et al. 1992b, Williams et al. 1992, Reinhardt et al. 1993, Schulte et al. 1993, Haywood et al. 1994, Schulte et al. 1994, Matis et al. 2002). These side effects were thought to be minor and transient, disappearing soon after completion of the treatment. At that point, speculation could only be made as to the longevity of NGVB and the long-term sequelae of the side effects associated with this tooth lightening technique.

The purpose of this chapter is to summarize the literature on the long-term effects of NGVB. Efficacy of NGVB using trays and strips and treatment solutions of various concentrations has been discussed elsewhere. Although several clinical studies will be cited, the emphases of this chapter will come from long-term NGVB studies in which I have been involved (Haywood et al. 1994, Leonard et al. 1997a, Leonard et al. 2001, Ritter et al. 2002, Boushell et al. 2012). In all the studies cited, unless otherwise noted, participants used a 10% carbamide peroxide bleaching solution at night for up to 8 hours. Specifically, the purpose of this chapter is to discuss the longevity, post-treatment effects, and long-term results of NGVB using a 10% carbamide peroxide bleaching solution.

Some content originally published in Leonard R. (2003) Long-term treatment results with Nightguard Vital Bleaching. Compend Contin Educ Dent 24(4A):364–74. Copyright © 2003 AEGIS Communications. All rights reserved. Reprinted with permission from the publisher.

LONGEVITY

“How long does bleaching last?” was a question posed by both patients and dental clinicians in the early 1990s. The literature did report the efficacy of NGVB (up to 98%), with a certain percentage of patients reporting side effects (up to two thirds); however, nothing existed in the literature related to longevity (Darnell et al. 1990, Haywood 1991c, Haywood 1992b, Ouellet et al. 1992, Gegauff et al. 1993, Reinhardt et al. 1993, Haywood et al. 1997, Sagel et al. 2000). In 1990 Dr. Van Haywood began an NGVB clinical study to evaluate efficacy, longevity, and occurrence of side effects. This patient cohort was followed for 12 years. As stated by Haywood et al. in their original article, 74% of the patients who initially responded to NGVB treatment and had not re-treated were satisfied with the shade of their teeth at 1.5 years after treatment (Haywood et al. 1994). Satisfaction decreased to 62% at 3 years after treatment. Ritter et al. reported on the same cohort of participants 9–12 years after treatment (mean 10 years). Shade retention and satisfaction at 10 years after treatment was 43% (Ritter et al. 2002). Only one participant at the 10-year recall appointment felt that the teeth had regressed back to the baseline shade.

Two other long-term studies worth consideration have followed patients for 47 months (Leonard et al. 2001) and 90 months (Leonard et al. 1997a). As reported in the 47-month longitudinal study by Leonard et al. (2001), the efficacy rate for the treatment solution used was 98%. The treatment time was 2 weeks using a viscous 10% carbamide peroxide solution. The bleaching effect was observed at 47 months (range 36–55 months) after treatment in 89% of the participants. Eighty-two percent still had at least a two-shade change from baseline, and on average the participants had a mean shade value of five Vita shade units lighter than baseline at 47 months after treatment.

With respect to the 90-month (range 84–100) study using a 6-month extended treatment time for patients with tetracycline-stained teeth, 60% were still satisfied with the shade of their teeth, with no one reporting tooth darkening back to the original shade (Leonard et al. 1997a). Thirty-six percent (four) of the participants had re-treated their teeth between the 54- and 90-month recall appointments. Eighty-eight percent of the participants had at least a two-shade Vita shade tab change from baseline at 90 months after treatment. Overall, the participants had a mean shade value of 10 Vita shade units lighter than baseline. Patients were given a satisfaction survey to complete before their clinical examination. According to the survey, patients were satisfied with the efficacy of the procedure and shade retention after treatment. It was noted in the study that shade regression occurred within the first 6 months after the completion of treatment and that the shade remained stable thereafter and would be consistent if the patient was not exposed to any more tetracycline products.

Boushell et al. (2012) reported on a cohort of patients who had successfully bleached their teeth and were at least 10 years post-treatment and as long as 17 years post-treatment (mean 12.3 years). Thirty-one of approximately 150 participants in various NGVB studies were evaluated clinically and asked to complete a questionnaire regarding their perceptions of the bleaching procedure. In this study it was reported that 35% of the patients who underwent NGVB with no additional retreatment were satisfied with results for up to 17 years post-treatment (Figures 19.1–19.3, Table 19.1).

In summary, longitudinal studies have documented that NGVB can be an effective method to lighten stained or discolored teeth. The longevity and stability as determined by both clinician examination and patient perception have also been documented. The results of these studies are consistent with overall long-term trends in levels of patient satisfaction, indicating that approximately one third of the patients who use NGVB will likely experience long-term satisfactory results.

Another question that patients ask is, “Will I need to re-treat, and if so, how often?” Based on the information that now exists in the literature, patients should be informed that in some cases a touch-up or re-treatment procedure may be needed after treatment (Haywood et al. 1994, Leonard et al. 1997a, Leonard et al. 2001, Burrows 2009). From the data gathered from the aforementioned studies, the re-treatment may take only 1 or 2 days to complete. It is important to point out to patients that, just as with the original treatment, the touch-up bleaching procedures should be done under the direct supervision of a dentist. As reported in the original study by Haywood et al., patients re-treated only after a mean of 25 months post-treatment (Haywood et al. 1994). In Leonard’s 47-month study, re-treatment occurred at 32 months (range 24–42), and in the extended treatment time for tetracycline-stained teeth, participants re-treated at least 54 months post-treatment (Leonard et al. 2001). Therefore the shade retention of NGVB can be noted in approximately one third of patients up to 17 years post-treatment without any touch-up treatment during that time. The results of these studies should help strengthen the fact that touch-up bleaching is not routinely needed.

POST-TREATMENT EFFECTS

SIDE EFFECTS

As previously stated, two thirds of patients undergoing NGVB may experience side effects, primarily tooth sensitivity and gingival irritation. Why some patients develop side effects and others do not is not fully understood, especially because all patients are exposed to the same chemical byproducts of carbamide peroxide degradation. Leonard et al. conducted an NGVB clinical study in which 20% of the participants reported sensitivity to wearing the treatment guard without any treatment solution and 36% reported sensitivity to a placebo (Leonard et al. 2002). In a second study by Leonard et al., 7.5% of the participants reported sensitivity to wearing the guard alone (Leonard et al. 2004). It was concluded that factors other than the treatment solution play a major role in the occurrence of side effects as reported by patients. There is no doubt that the cause of tooth sensitivity and/or gingival irritation is multifactorial (Leonard et al. 1997b).

The most likely cause for gingival irritation is the border of the tray extending onto the gingiva and trapping the bleaching solution against the gingival tissue. This can be corrected or avoided by trimming the treatment tray just short of the tissue. Haywood showed that even if the tray did not completely cover the entire tooth, the tooth would still lighten because of the angulation of the enamel rods.

Tooth sensitivity can come from many sources, but orthodontic movement of the teeth caused by the tray as well as penetration of the carbamide peroxide through the tooth structure and into the pulp is one likely cause. Increased carbamide peroxide exposure time and carbamide peroxide concentration will also increase the risk of developing tooth sensitivity. On the market today are various bleaching formulations using additives such as amorphous calcium phosphate, fluoride, and/or potassium nitrate that may decrease the risk of tooth sensitivity. Haywood et al. (2005) demonstrated that the use of a potassium nitrate plus fluoride dentifrice for 2 weeks before bleaching as well as throughout the treatment procedure was useful in the management of bleaching-induced tooth sensitivity. Leonard et al. (2004) reported that a 30-minute application of a 3% potassium nitrate and 0.11% fluoride desensitizing agent before bleaching was useful in decreasing tooth sensitivity, especially in a population at risk for developing tooth sensitivity during bleaching.

Stay updated, free dental videos. Join our Telegram channel

Join