A Segura’s research while affiliated with The University of Texas at San Antonio and other places

To compare the efficacy and safety outcomes of two tooth-whitening systems. 44 subjects, 12-17 years of age, participated in the study and were divided into two balanced groups. 15 subjects received 6.5% hydrogen peroxide professional whitening strip treatment and 29 subjects received 9.5% hydrogen peroxide high-adhesion whitening strips to wear for 30 minutes twice a day. Teeth were bleached for 20 days with the 9.5% hydrogen peroxide strips and 21 days with the 6.5% hydrogen peroxide strips. Digital image analysis measured color in b*, L*, and a* color spaces, where b* indicated yellowness, L* indicated lightness, and a* indicated redness at days 8, 11 and 22 for both the maxillary and mandibular arches. Oral examinations and interviews were used to ascertain any adverse events that may have occurred during treatment. 36 subjects completed the study. At each post-baseline visit, both of the treatment groups had statistically significant (P < 0.02) mean color improvement from baseline for b*, L* and a*. The 9.5% hydrogen peroxide strips group provided statistically greater reduction in yellowness (deltab*) relative to the 6.5% hydrogen peroxide strips group for each visit of in the maxillary arch (P < 0.02) and for Day 8 and Day 22 in the mandibular arch (P < 0.02). In addition, the 9.5% hydrogen peroxide high-adhesion strip group provided statistically greater improvement in lightness (deltaL*) relative to the 6.5% hydrogen peroxide strip group for each visit in the maxillary arch (P < or = 0.007) and for the final visit in the mandibular arch (P = 0.002). 18 subjects (62%) in the 9.5% hydrogen peroxide high-adhesion strip group reported adverse events compared to 8 subjects (53%) in the 6.5% hydrogen peroxide polyethylene strip group. Minor and transient tooth sensitivity and oral irritation were the most common adverse events.

Objective: As a sensitive and quantitative tool, Quantitative Light-Induced fluorescence (QLF) has been widely used to detect tooth demineralization. The loss of enamel mineralization is indicated by fluorescence loss with respect to surrounding sound enamel. The correlation between fluorescence loss and the status of mineralization has been studied thoroughly, however, the correlation between the fluorescence loss and demineralization depth are not fully understood. The purpose of this project was to study this correlation to estimate demineralization depth. Methods: Extracted teeth were collected. Artificial caries-like lesions were created and imaged with QLF. Novel image processing software was developed to measure the largest percent of fluorescence loss in the region of interest. All teeth were then sectioned and imaged by polarized light microscopy. The largest depth of demineralization was measured by NIH ImageJ software. The statistical linear regression method was applied to analyze these data. Results: The linear regression model was Y = 1.485 X+1.745, where X was the largest percent loss of fluorescence and Y was the deepest depth of demineralization. The correlation coefficient was 0.9696. The two-tailed t-test for coefficient was 7.93, indicating the p-value = 0.0014. The F test for the entire model was 62.86, which shows the p-value =0.0013. Conclusion: The results indicated statistically significant linear correlation between the largest percent loss of fluorescence and depth of the deepest enamel demineralization. This would facilitate in-vivo measurement of demineralization using the non-invasive QLF technique, based on this linear model. This method provides dentists critical information about the depth of demineralization when treatment planning dental care for patients. This research was supported, in part, by NIDCR 5 RO1 DE017875-03.

A randomized controlled clinical trial was conducted to compare two professional at-home tooth whitening systems in a teenage population. Informed consent and child assent were obtained from 60 teenagers aged 12-17 (mean age = 14.8). After baseline measurements, subjects were randomized to one of two groups, using either 14% hydrogen peroxide whitening strips or 10% carbamide peroxide in a custom bleaching tray. Strips were used for 30 minutes twice daily, while the tray was worn overnight. Treatment took place for 14 days sequentially, first on the maxillary arch and then on the mandibular arch; all use was unsupervised. Efficacy was measured objectively by L*a*b* color change from digital images obtained at baseline and end of treatment, using combined color measures for both arches. Both professional whitening systems had significant (p < 0.0001) reductions in yellowness (Deltab*) and increased lightness (DeltaL*) after two weeks of treatment on each arch. At the end of treatment, Deltab* or DeltaL* did not differ significantly between the groups (p > 0.28). Tooth sensitivity and mild oral irritation represented the most common adverse events, with only one subject discontinuing treatment as a result. Teenagers who used either bleaching method for two weeks experienced significant tooth whitening without serious adverse events.

The purpose of this study was to compare the efficacy and safety outcomes of a currently marketed, peroxide-containing, tray-based, tooth-whitening system to a peroxide-containing, "trayless" tooth-whitening system. Fifty-seven subjects, 12 to 17 years of age, participated in this study and were divided into 2 balanced groups. Twelve subjects received custom trays with 10% carbamide peroxide gel that they were instructed to wear overnight. Forty-five subjects received 10% hydrogen peroxide polyethylene strips to wear for 30 minutes twice a day. Teeth were bleached for 2 weeks. Digital image analysis measured color in B, L, and A color spaces, where B indicated yellowness, L indicated lightness, and A indicated redness. Oral examinations and interviews were used to ascertain any adverse events that may have occurred during treatment. Fifty-one patients completed this study. Both whitening systems yielded significant (P<.001) color improvement, as evidenced by decreased yellowness, increased lightness, and decreased redness. Groups did not differ significantly (P>.39) regarding color improvement for B, L, or A on either the maxillary or mandibular teeth. Twelve subjects (27%) in the polyethylene strip group reported adverse events compared to 5 subjects (42%) in the tray-delivered group. Minor and transient tooth sensitivity and oral irritation were the most common adverse events. Both the daytime strip and overnight tray groups significantly (P<.0001) whitened teeth; there were no significant differences between the 2 groups in any of the color parameters; both whitening systems were well tolerated, and most adverse events were mild in severity.

To compare the plaque removal efficacy of a positive control power toothbrush (Colgate Actibrush) to an experimental power toothbrush (Crest SpinBrush) following a single use. This study was a randomized, controlled, examiner-blind, 4-period crossover design which examined plaque removal with the two toothbrushes following a single use in 39 completed subjects. Plaque was scored before and after brushing using the Turesky Modification of the Quigley-Hein Index. Baseline plaque scores averaged 2.18 and 2.16 for the experimental toothbrush and control toothbrush treatment groups, respectively. With respect to all surfaces examined, the experimental toothbrush delivered an adjusted (via analysis of covariance) mean difference between baseline and post-brushing plaque scores of 0.66 while the control toothbrush delivered an adjusted mean difference of 0.43. This represents an increase of 55% plaque removal relative to the control power toothbrush. The difference between brushes was statistically significant (P < 0.001). With respect to buccal and lingual surfaces, the experimental toothbrush delivered very consistent results relative to the control toothbrush. The differences between brushes were also statistically significant (P < 0.001).

To measure, over time, the release of fluoride from a resin-modified glass-ionomer cement, loaded with different levels of fluoride, then to evaluate the adjacent dentin demineralization inhibition relative to these fluoride levels. (Phase I) 25 standardized discs were fabricated from a non-fluoridated resin-based composite (control), resin-modified glass-ionomer cement and resin-modified glass-ionomer cement loaded with sodium fluoride at 1%, 2% and 3% by weight fluoride. Fluoride release was evaluated over 30 days. (Phase II) 50 restorations, from the materials listed in Phase I, were placed as Class V restorations in teeth, the teeth were acid-challenged, then dentin margins adjacent to restoration margins were evaluated for demineralization. As sodium fluoride additions increased, fluoride release increased. Evaluation of demineralization indicated the resin-modified glass-ionomer cement inhibited adjacent demineralization in a direct relationship with sodium fluoride concentration where 3% fluoride exhibited significantly less adjacent demineralization than all other groups; 2% and 1% fluoride exhibited significantly less adjacent demineralization than the non-loaded resin-modified glass-ionomer cement and non-fluoridated resin-based composite control (P< 0.05).

The authors retrospectively evaluated the clinical performance of one resin-modified glass ionomer cement as a restorative material in Class I, Class II, Class III and Class V restorations in primary teeth. A total of 306 patients who had received a total of 864 resin-modified glass ionomer restorations, which had been in their mouths for a minimum of three years, were included in this evaluation. The authors assessed the clinical observations recorded in patients' records and used bitewing radiographs to assess Class II restorations. The authors found an overall restoration success rate of 93.0 percent, with Class I restorations having a 92.6 percent success rate, Class II restorations having a 93.3 percent success rate, Class III restorations having a 100 percent success rate, and Class V restorations having a 98.0 percent success rate. The resin-modified glass ionomer cement functioned well as a Class I, Class II, Class III and Class V restorative material in primary teeth. Resin-modified glass ionomer restorative cement is a durable and reliable material to use for Class I, Class II, Class III and Class V restorations in primary teeth. Therefore, dentists have a proven alternative to silver amalgam and resin-based composite for primary tooth restoration.

The purpose of this study was to examine the in vitro remineralization of incipient caries lesions on teeth adjacent interproximally to teeth with Class II glass ionomer cement restorations. Sixty-four extracted molars were selected and 1 x 5 mm artificial caries lesions were created at the interproximal contact point. One hundred micrometer sections were obtained at the caries sites, and polarized-light photomicrographs were obtained. The sections were covered with varnish, leaving only the external section site exposed, and were placed back into the original tooth. In another sixty-four molars, Class II cavities were prepared. Equal numbers of preparations were filled with Fuji IX GP, Vitremer, Ketac-Molar, or Z 250. These sixty-four teeth were mounted to have interproximal contact with the adjacent teeth containing the artificial caries lesions. Specimens were placed in closed environments of artificial saliva for one month. After thirty days, the same sections were photographed again under polarized light, and areas of the lesions were quantitated. Decrease in the size of caries lesions indicated the glass ionomers had significantly greater remineralization effects on adjacent caries than the nonfluoridated composite resin (ANOVA p < 0.05). There were no significant differences among the three glass ionomers tested.

The ability of fluoride-releasing resins to inhibit dentin demineralization remains controversial. The purpose of this study was to evaluate the caries inhibition of resin composite restorations with an experimental fluoridated hydroxyethyl methyl methacrylate (HEMA) and water wetting agent. Standardized Class V preparations were placed in 40 molars, the gingival margin placed below the cementoenamel junction. Two dentin primers (sodium fluoride, HEMA and water; HEMA and water) were placed in equal numbers of 20 preparations, then One-Step Dental Adhesive (Bisco) was applied as recommended by the manufacturer, followed by the placement of a resin composite restoration. Amalgam restorations with no primer/adhesive were placed in 10 preparations and 10 preparations were restored by placing One-Step Dental Adhesive, then resin composite. All teeth were subjected to an artificial caries challenge (pH 4.4) for 5 days. Results demonstrated the mean areas (microm2 +/- s.d.) of demineralization 100 microm from the restoration/dentin margin to be: amalgam 5,570 +/- 873; One-Step 7,038 +/- 2,099; HEMA and water 6,126 +/- 634; fluoridated HEMA and water 3,411 +/-593. ANOVA and Duncan's test (P < 0.05) demonstrated the fluoridated HEMA and water wetting agent to have significantly less adjacent dentin demineralization than the other three groups. Eighty percent of HEMA and water wetting agent, 80% of One-Step Dental Adhesive and 100% of amalgam restorations demonstrated wall lesions. One hundred percent of restorations with fluoridated HEMA and water wetting agent demonstrated inhibition zones in adjacent dentin.

The authors clinically examined two restorative materials to evaluate their effectiveness in Class II restorations in primary molars and their ability to inhibit recurrent caries. Forty subjects, each in need of two Class II restorations in primary molars, took part in this study. Each patient received one Class II restoration of resin-modified glass ionomer cement and one of amalgam. The authors evaluated the restorations at six-month, one-year, two-year and three-year recall appointments. On exfoliation, teeth with experimental restorations were retrieved and microscopically examined for inhibition of demineralization at restoration margins. The results of the clinical evaluation demonstrated no significant differences between the resin-modified glass ionomer cement restorations and the amalgam restorations (P < .05). Polarized light microscopic examination of the returned teeth that were restored as a part of this study indicated that the resin-modified glass ionomer cement had significantly less enamel demineralization at restoration margins than did amalgam (P < .0001). The resin-modified glass ionomer cement functioned clinically as well as amalgam for Class II restorations in primary molars. However, the resin-modified glass ionomer exhibited significantly less enamel demineralization at restoration margins than did amalgam. Resin-modified glass ionomer cement restorative material functions well for Class II restorations in primary molars and exhibits less recurrent caries at restoration margins than does amalgam.