Hexametaphosphate effects on tooth surface conditioning film chemistry--in vitro and in vivo studies

These studies compared the effects of Crest Dual Action Whitening dentifrice with sodium hexametaphosphate and control commercial dentifrices on the surface chemistry of conditioning film-coated dental enamel in vitro and in vivo. Conditioning film chemistry was studied by measurements of film thickness, ability to wet the surface/surface energy, conditioning film chemical composition and zeta potential. Laboratory and in vivo studies demonstrated that brushing and chemical-only treatment of pellicle-coated enamel surfaces produced marked changes in surface chemistry. Brushing of surfaces with all commercial dentifrices significantly reduced pellicle film quantity. Effects on non-brushed areas, of significance in the clinical situation, were different for different dentifrices. For dentifrice chemical treatments, calcium phosphate surface active builders, such as pyrophosphate and hexametaphosphate, produced stronger effects than standard (non-tartar control) dentifrices, peroxide baking soda dentifrices and dentifrices formulated with carboxylate polymers, viz. Colgate Total with copolymer. Crest Dual Action Whitening hexametaphosphate dentifrice removed more pellicle conditioning film, produced a lower zeta potential, produced the largest changes in film composition and had the greatest impact on surface free energies of the tested dentifrices. Crest Dual Action Whitening dentifrice also produced lasting changes in the reacquisition of pellicle conditioning film, as established by in vitro cycling immersion studies. Crest Dual Action Whitening dentifrice produced stronger and more lasting effects on surface film chemistry than low molecular weight pyrophosphate (Crest Tartar Control) or other polymeric-based dentifrice systems (Colgate Total). These surface chemistries may contribute to the unique clinical actions of hexametaphosphate established in recently reported, randomized clinical studies of tartar control, stain prevention and stain removal effects.     

Chronic oral inflammation and the progression of periodontal pathology in the third molar region.

PURPOSE: To assess the association between risk markers of chronic oral inflammation and changes over time in periodontal probing depth (PD) in the third molar region, the distal of a second molar, or around a third molar. SUBJECTS AND METHODS: The data from these analyses are part of a study of subjects enrolled with 4 asymptomatic third molars with adjacent second molars in an institutional review board-approved longitudinal trial. Full-mouth periodontal probing was conducted at enrollment and follow-up. Enrollment levels of periodontal pathogens and gingival crevicular fluid inflammatory mediators were assayed as indicators of the degree of oral inflammation. Subjects were categorized as those who had at least a 2 mm change in periodontal PD between baseline and follow-up in the third molar region and those who did not. The relationship between aggregated subject baseline PD, levels of periodontal pathogens, and gingival crevicular fluid IL-1 beta, and the proportion of subjects with changes in PD >or=2 mm versus those with PD <2 mm were compared with Cochran-Mantel-Haenzsel statistics. Level of significance was set at 0.05. Risk assessment models for a change in PD >or=2 mm were developed using logistic regression analysis. RESULTS: Twenty-four percent of 254 subjects exhibited a change in PD from baseline to follow-up of >or=2 mm in the third molar region. Of these, 95% had a baseline PD of >or=4 mm. Both high (>or=10(5)) "orange" and "red" complex bacteria and PD of >or=4 mm detected at enrollment were significantly associated with a change in PD >or=2 mm. Odds of a change in PD >or=2 mm were increased if baseline pathogen levels were >or=10(5) or a PD of >or=4 mm was detected at enrollment. CONCLUSION: Our findings are consistent with chronic oral inflammation leading to a progression of periodontal disease in the third molar region.     

Onset and duration periods of articaine and lidocaine on maxillary infiltration.

OBJECTIVES: The aim of this study was to compare the onset and duration of pulpal anesthesia by maxillary infiltration using 2% lidocaine with 1:100,000 epinephrine, 4% articaine with 1:200,000 epinephrine, and 4% articaine with 1:100,000 epinephrine. METHOD AND MATERIALS: Twenty healthy patients randomly received 1.8 mL of one of the three local anesthetics during operative dentistry procedures of low complexity on three maxillary posterior teeth. Onset and duration were determined using an electric pulp tester. RESULTS: The mean values for pulpal onset were 2.8, 1.6, and 1.4 minutes and for pulpal duration were 39.2, 56.7, and 66.3 minutes, respectively, for 2% lidocaine with 1:100,000 epinephrine, 4% articaine with 1:200,000 epinephrine, and 4% articaine with 1:100,000 epinephrine. Statistical analysis by the Kruskal-Wallis nonparametric test showed significant differences with better results (shorter onset and longer duration periods) for both articaine solutions compared with the lidocaine solution. Although 4% articaine with 1:100,000 epinephrine clinically presented the shortest onset and the longest duration periods, there was no statistically significant difference between the articaine solutions. CONCLUSION: Both articaine solutions produced shorter onset and longer duration of pulpal anesthesia by maxillary infiltration than the lidocaine solution did. Statistical analysis did not confirm better clinical results of 4% articaine with 1:100,000 epinephrine than with 4% articaine with 1:200,000 epinephrine.     

Comparison of a stabilized stannous fluoride/sodium hexametaphosphate dentifrice and a zinc citrate dentifrice on plaque formation measured by digital plaque imaging (DPIA) with white light illumination

OBJECTIVES: The objectives of this study were to verify use of a white light-illuminated adaptation of an established digital plaque image analysis (DPIA) technique to measure changes in plaque levels, and to compare the antiplaque efficacy of a 0.454% stannous fluoride/sodium hexametaphosphate dentifrice (SnF2/SHMP) and a 0.76% sodium monofluorophosphate/zinc citrate (ZnCit/SMFP) dentifrice using the white light DPIA system. METHODS: White Light DPIA Qualification--17 subjects were enrolled in the study. The following four images were captured on different days: a) non-disclosed morning plaque; b) disclosed morning plaque; c)just-brushed plaque; and d) post-prophylaxis plaque levels. Comparative Dentifrice Assessment-Following the qualification study, 21 subjects were enrolled in the dentifrice assessment. During Phase I (two weeks acclimatization phase), subjects used a standardized oral hygiene regimen twice per day, consisting of a sodium fluoride dentifrice and a standard flat-profile manual toothbrush. In Phase II (two-week treatment phase), subjects were randomized to one of two treatment groups: SnF2/SHMP dentifrice (Crest Pro-Health) or the ZnCit/SMFP formulation (Viadent). During each phase, plaque levels were assessed in the morning prior to the morning tooth brushing (a.m.), post-brushing in the morning (p.b.), and in the afternoon (p.m.). RESULTS: White Light DPIA Qualification--All 17 subjects completed the trial. The white light modification of DPIA successfully distinguished known variations in plaque coverage. Mean plaque coverage of the 12 anterior facial surfaces, as determined by the system for the four images, was: a) 0.07%; b) 11.44%; c) 4.99%; and d) 2.16%. Comparative Dentifrice Assessment-All 21 subjects completed the study. The SnF2/SHMP dentifrice provided a statistically significant 25% lower a.m. pre-brushing plaque level (p = 0.0385) versus ZnCit/SMFP. SnF2/SHMP also showed a directional 23% lower p.m. plaque (p = 0.09) level, and 15% less (p = 0.10) post-brushing plaque compared to ZnCit/SMFP. CONCLUSION: The white light DPIA system was shown to be a sensitive method to measure changes in plaque levels. Using this system, a SnF2/SHMP dentifrice was found to be significantly more effective than a ZnCit/SMFP dentifrice in the prevention of overnight plaque growth.     

Effects of hydrogen peroxide bleaching strip gels on dental restorative materials in vitro: surface microhardness and surface morphology

OBJECTIVE: This study examined the effects of peroxide tooth bleaching, including Crest Whitestrips hydrogen peroxide gel treatments, on the surface hardness and morphology of common dental restorative treatments. METHODOLOGY: American Dental Association (ADA) recommended dental restorative materials, including amalgam, dental gold, porcelain, glass ionomer, and composites, were prepared according to manufacturers' instructions. A cycling treatment methodology was employed which alternated ex vivo human salivary exposures with bleaching treatments under conditions of controlled temperature and durations of treatment. Bleaching treatments included commercial Crest Whitestrips bleaching gels, which utilize hydrogen peroxide as the in situ bleaching source, and several commercial carbamide peroxide bleaching gels. Control treatments included placebo gels and an untreated group. Crest Whitestrips bleaching included treatment exposures simulating recommended clinical exposures (14 hours), along with excess bleaching simulating exposure to five times suggested Crest Whitestrips use. At the conclusion of treatments, surface microhardness measures and surface morphological assessments with standard and variable pressure (VP-) SEMs were conducted to assess the effects of bleaching exposure on the surface morphology and structural integrity of the restoratives. RESULTS: Surface microhardness and SEM measures revealed no significant deleterious effects on the restoration surfaces from Whitestrips gels. CONCLUSION: These results confirm that tooth bleaching from the selected commercial hydrogen peroxide or carbamide peroxide bleaching systems does not produce changes in surface morphology or microhardness of common dental restorative materials. These results support the clinical safety of the selected commercial bleaching systems to the oral environment, matching results obtained from long-term use of these ingredients applied in dental offices and available in commercial formulations.     

Effects of Er:YAG laser compared to ultrasonic scaler in periodontal treatment: a 2-year follow-up split-mouth clinical study

BACKGROUND: The aim of this clinical study was to compare the results of non-surgical treatment of periodontal disease with an erbium-doped:yttrium, aluminum, and garnet (Er:YAG) laser to root debridement with an ultrasonic scaler. METHODS: Twenty-five patients furnished two quadrants containing four teeth with probing depths (PD) >4 mm; the quadrants were divided equally between the right and left sides. On one side, teeth were treated by Er:YAG laser using 160 mJ/pulse at 10 Hz (test group); on the contralateral side, teeth were treated by ultrasonic scaler (control group). Clinical baseline data, including plaque index, gingival index, probing depth (PD), and clinical attachment level (CAL), were recorded before treatment and at 3 months and 1 and 2 years. RESULTS: There were statistically significant differences in PD between the test and control groups for pockets of 1 to 4 mm (P <0.05), 5 to 6 mm (P <0.01), and > or =7 mm (P <0.001). However, there were no significant differences between the test and control groups for CAL gain in pockets of 1 to 4 mm; statistically significant differences were found between the test and control groups in pockets of 5 to 6 mm (P <0.01) and > or =7 mm (P <0.001). CONCLUSION: Er:YAG laser periodontal treatment resulted in statistically significant improvements in PD and CAL gain compared to ultrasonic scaler treatment at 2-year follow-up, especially in moderate and deep pockets.     

The effects of high concentration tooth whitening bleaches on microleakage of Class V composite restorations

OBJECTIVE: To explore the effects of high-concentration hydrogen peroxide bleaching agents on the microleakage of composite restorations. METHODS: In 60 extracted human molars, Class V restorations were prepared with Scotchbond 1/Filtek Z250 composite. Teeth were randomly divided into four groups: (1) no bleaching; (2) bleaching with 14% hydrogen peroxide gel from Crest Whitestrips; (3) bleaching with 20% carbamide peroxide gel from Opalescence PF 20; and (4) bleaching with 38% hydrogen peroxide gel Opalescence Xtra Boost. Bleaching procedures were carried out at 37 degrees C for 21 days/42 hours (2); seven days/42 hours (3); one day/45 minutes (4). Varnish was applied on the apical portion of the teeth only, excluding the restoration, prior to immersion in a 0.1% rhodamin-B-isothiocyanate solution for 24 hours at 37 degrees C. After rinsing, specimens were embedded in methacrylate blocks, and sectioned with a water-cooled microtome with three restoration cuts positioned centrally parallel to the long axis of the tooth. Microleakage was evaluated at the occlusal margins of the Class V restorations using a stereo microscope, separate for dentin and enamel margins. RESULTS: Over 90% of enamel margins exhibited no microleakage following cycling. Bleaching agents had almost no effect on numerical averages. Eighty-eight percent of the dentin margins were free of microleakage for the non-treated control group. Bleaching treatments collectively had slight numerical reductions to around 80%. The statistical evaluation (Kruskal-Wallis-test) showed no significant difference in microleakage between groups for enamel or dentin. CONCLUSION: Bleaching with the materials tested had no influence on microleakage of Filtek Z250 composite bonded with Scotchbond 1.     

Removal of extrinsic stain using a 7.0% sodium hexametaphosphate dentifrice: a randomized clinical trial

A nine-week, randomized and controlled clinical trial was conducted to compare the stain removal efficacy of a 0.243% sodium fluoride dentifrice containing 7% sodium hexametaphosphate (5% hexametaphosphate anion) to that of a 0.243% sodium fluoride control dentifrice. Following prophylaxis and a three-week pre-treatment period to induce extrinsic stain, healthy adult volunteers with tooth stain were randomized to the sodium hexametaphosphate dentifrice or the control. Stain area and intensity were assessed at baseline, three and six weeks. At both three and six weeks, the sodium hexametaphosphate dentifrice was statistically significantly superior to the control for all overall stain measures (p < 0.04). After six weeks of product usage, the sodium hexametaphosphate dentifrice demonstrated reductions of 29% in composite stain, 24% in stain intensity, and 25% in stain area relative to the control. Significant reductions in composite stain were seen on both gingival and body regions for the sodium hexametaphosphate dentifrice versus the control at three and six weeks. Both products demonstrated favorable safety profiles, as determined by oral soft tissue evaluations and recording of subject-reported adverse events.     

Pain prevalence and severity before, during, and after root canal treatment: a systematic review

Introduction

Anticipation and experience of root canal associated pain is a major source of fear for patients and a very important concern of dentists. Pretreatment, treatment, and posttreatment pain is anticipated, experienced, remembered, and shared by patients. The purpose was to determine the influence of root canal treatment on pain prevalence and severity and estimate the prevalence and severity of pretreatment, treatment, and posttreatment pain in patients receiving root canal treatment.

Methods

Defined searching of MEDLINE, Embase, Cochrane, and PsycINFO databases identified 5,517 articles. Systematic review, including title scanning, abstract scanning, full-text review, and quality rating, provided 72 studies for meta-analysis. L’Abbe plots were used to evaluate the influence of root canal treatment on pain prevalence and severity. Pretreatment, treatment, and posttreatment pain prevalence and severity data were analyzed.

Results

L’Abbe plots revealed that pain prevalence and severity decreased substantially after treatment. Mean pretreatment, 24-hour posttreatment, and 1-week posttreatment pain prevalences with associated standard deviations were 81 (28%), 40 (24%), and 11 (14%), respectively. Pretreatment, 24-hour posttreatment, and 1-week posttreatment pain severities, on a 100-point scale, were 54 (24%), 24 (12%), and 5 (5%), respectively. Supplemental injections were frequently required (60 [24%]).

Conclusions

Pretreatment root canal-associated pain prevalence was high but dropped moderately within 1 day and substantially to minimal levels in 7 days. Pretreatment root canal-associated pain severity was moderate, dropped substantially within 1 day of treatment, and continued to drop to minimal levels in 7 days. Supplemental anesthesia was often required.