Plaque Removed Research Articles

Efficacy of the lift-the-lip technique for dental plaque removal in preschool children.

The objective of this study was to compare the efficacy of two dental brushing techniques in relation to the lift lip method to control oral hygiene. This controlled and randomized field trial included 40 preschool children aged 24-59 months, divided into four groups: Group A (modified bass without lift the lip), Group B (modified bass with lift the lip), Group C (horizontal technique with lift the lip), and Group D (horizontal technique without lift the lip). The dental plaque accumulation was recorded through the O'Leary index. In addition, to perform hygiene control, the plaque index was performed in the initial evaluation at 7 and 14 days. ANOVA and Friedman test were applied to compare oral hygiene in each group. Finally, Kruskal-Wallis test was applied to compare groups at 7 and 14 days. The children with the modified Bass associated to the lift the lip had significantly more plaque removed at 7 (P = 0.041) and 14 days (P = 0.027) than other techniques. The modified Bass related to the lift-the-lip technique was the most effective for plaque removal in preschool children at 7 and 14 days.

Removing atherosclerotic plaque created using high cholesterol diet in rabbit using ultrasound.

BackgroundThe aim of the proposed study was to conduct a feasibility study using a flat rectangular (3 × 10 mm2) transducer operating at 5 MHz for removing atherosclerotic plaque in an in vivo model. The proposed method can be used in the future for treating atherosclerotic plaques in humans.Methods and resultsThe plaque in the rabbits was created using high cholesterol diet for 4 months. The amount of plaque removed was studied as a function of intensity, with a fixed pulse repetition frequency (PRF), and duty factor (DF).ConclusionsThe amount of plaque removed is directly related to the acoustic intensity. It was found that the presence of bubbles accelerates the removal of plaque. In order to ensure that pure mechanical mode ultrasound was used, the intensity used does not produce temperatures that exceed 1°C.

Interproximal access efficacy of three manual toothbrushes with extended, x‐angled or flat multitufted bristles

This laboratory research study was conducted to evaluate three manual toothbrushes for their ability to remove artificial plaque from interproximal sites. Interproximal access efficacy (IAE) was evaluated using a pressure-sensitive artificial plaque substrate placed around simulated anterior and posterior teeth with horizontal and vertical brushing motions. Efficacy was determined as the maximum width of artificial plaque removed from around the teeth. Testing was conducted on three manual toothbrushes with different bristle configurations coded as: Extended [Aquafresh Between Teeth (also marketed as Dr. Best Zwischenzahn)], X-angled (Oral-B CrossAction) and Flat multitufted (Oral-B Indicator). Twenty-four tests on each toothbrush design were conducted, and the results were statistically analysed using two-sample t-tests, assuming unequal variances. The individual mean IAE values on anterior and posterior tooth shapes with vertical and horizontal brushing were significantly (P < 0.001) higher for the toothbrush with extended bristles (Aquafresh Between Teeth) than for the other two toothbrush designs tested. When the data were combined to give an overall average, the IAE for the toothbrush with extended bristles (Aquafresh Between Teeth) was significantly (P < 0.001) higher than the IAE value for the toothbrushes containing x-angled (Oral-B CrossAction) or flat multitufted bristles (Oral-B Indicator). Based on the demonstrated predictability of the IAE assay for clinical interproximal plaque removal, the manual toothbrush with extended bristles should be an effective brush for cleansing the dental interproximal sites.

Clinical evaluation of brushing time and plaque removal potential of two manual toothbrushes

To compare plaque removal efficacy of Oral-B CrossAction (CA) used for 1 min with an American Dental Association (ADA) manual toothbrush used for 2 or 5 min in an examiner-blind, three-treatment, six-period crossover study. After refraining from all oral hygiene procedures for 23-25 h, subjects were randomly assigned to one of nine possible six-period (visit) treatment sequences. Plaque was assessed at baseline (Rustogi Modified Navy Plaque Index). Post-brushing scores were recorded after brushing with a marketed dentifrice and the assigned toothbrush for the specified duration. The same procedure was followed at each of six subsequent visits. Clinical measurements were carried out by the same examiner. Forty subjects completed the study. All three treatments effectively removed plaque from the whole mouth, along the gingival margin and from approximal surfaces. Whole mouth and gingival margin plaque removal scores with CA for 1 min did not differ significantly from scores with the ADA toothbrush used for 2 min. The ADA brush used for 5 min showed significantly greater whole mouth (P < 0.001) and gingival margin (P < 0.001) plaque reduction than the two other treatments. Approximal plaque removal scores did not differ between the three treatments. Efficient plaque removal can be achieved after 1 min of brushing with CA. The amount of plaque removed did not differ significantly from that achieved with the ADA brush after 2 min of brushing. Greater whole mouth and gingival margin plaque removal scores were seen with the ADA brush after 5 min.

Correlations Between Two Plaque Indices in Assessment of Toothbrush Effectiveness

The Rustogi et al. Modified Navy (RMNPI) and Turesky et al Modification of the Quigley Hein (TQHPI) plaque indices are commonly used to measure plaque removal. This study evaluated the possible correlations of both indices using data relative to a single use assessment of plaque removal using commercially available toothbrushes. Single use crossover study designs have been previously reported. Disclosed plaque was scored pre- and post-brushing using both the RMNPI and the TQHPI. Sixty subjects, with an initial mean RMNPI score of 0.6 or greater, were enrolled and completed the study. No minimum score was required for TQHPI. After the initial scoring, the order for each index was randomized so that each subject was scored with either RMNPI followed by TQHPI or vice versa. Two manual toothbrushes [Oral-B CrossAction (CA) and Colgate Navigator (NA)] and one battery-powered brush (Crest SpinBrush Pro) (SBP) were evaluated in the trial. One examiner performed all clinical measurements. Pearson correlations were performed on whole mouth, buccal, and lingual plaque scores for the CA toothbrush. Strong positive correlations were found between the two plaque indices for pre- and post-brushing scores for the whole mouth and on lingual and buccal surfaces, where Pearson correlation coefficients ranged between 0.963 and 0.995. There was no correlation between the pre-brushing plaque score and the amount of plaque removed by brushing indicating that higher plaque levels before brushing do not necessarily predict that greater amounts of plaque will be removed during toothbrushing. Each toothbrush was found to be safe and significantly reduced plaque levels after a single brushing (t-test, p=0.0001). Significantly greater plaque reductions were found with the CA than the NA and SBP toothbrushes at whole mouth, lingual, and approximal surfaces for both indices (analysis of variance (ANOVA), p < or = 0.0002 for all comparisons). Strong positive correlations were found between two plaque indices (the RMNPI and TQHPI) for pre- and post-brushing scores at whole mouth, lingual, and buccal surfaces as assessed using data from a single use assessment of plaque removal. Efficacy data from this study demonstrated the CA toothbrush provided superior cleaning when compared to the NA manual toothbrush and SBP battery toothbrush. Two commonly used indices for assessing plaque removal in clinical studies are RMNPI and TQHPI. However, each index differs in the way plaque is scored. This study used both indices to assess comparative toothbrush efficacy and showed a strong correlation between indices for both pre- and post- brushing plaque scores. The result suggests that both indices demonstrate sufficient sensitivity to differentiate toothbrush efficacy.

A study on the plaque removal efficiency of new and worn toothbrushes

Increased plaque accumulation is associated with gingivitis1) and if not adequately removed may lead to periodontitis.2) Poor oral hygiene status usually increases the possibility of alveolar bone loss.3) It is now widely accepted that thorough plaque control will prevent the development and recurrence of periodontitis .4,5) Toothbrushing is the most widespread mechanical means of personal plaque control in the world6) and is considered to be an important factor in the long-term maintenance of periodontal health.7) The toothbrush is still the most common and often the only cleaning device people use. Therefore, its proper use is of importance in plaque control and prevention of periodontal disease. Many factors can influence the ability of an individual to remove plaque with a manual toothbrush. Brushing duration, brushing force and brushing technique will all either increase or decrease the amount of plaque removed and therefore, in the long term, influence gingival health. Another factor that is thought to affect brushing efficacy is toothbrush wear.8) Dental professionals and toothbrush manufacturers generally recommend that a toothbrush be replaced every three months. This is based on the supposition that a toothbrush is likely to be less effective than a new one. The American Dental Association also makes this recommendation, stating that worn brushes are not effective at removing plaque bacteria and broken bristles may injure gums.9) Evidence supporting the hypothesis that a brush is less effective at removing plaque than a new brush is, however, relatively scarce. Few studies have investigated the effect of toothbrush wear and those written on the subject have produced conflicting results. Studies by Kreifeldt et al.,10) Glaze and Wade11) and Warren et al.8) found that a toothbrush was significantly less effective at

Relationship between the plaque removal efficacy of a manual toothbrush and brushing force.

This survey investigated the association between the efficacy of plaque removal and toothbrushing forces during a normal brushing regime. The 94 subjects participating in this study were requested not to brush 24 h prior to the experiment. Panelists brushed for 1 min with a manual toothbrush. Before and after brushing, plaque was assessed using the Turesky modification of the Quigley & Hein plaque index. A second 1-min exercise of brushing was carried out to assess the toothbrushing force. The mean plaque reduction was 39%, with vestibular surfaces being cleaned most effective (69%) and the lingual surfaces the least (21%). The mean brushing force was 330 g. No correlation was observed between efficacy and brushing force (r=0.14, p=0.16). The relationship between pre- and post-brushing plaque was stronger (r=0.68, p<0.001). Multiple regression analysis entering squared values of force as an independent variable into the equation, indicated that the relation between efficacy and force was not linear. A curve could be fitted to the plot (p=0.0004), demonstrating that up to a certain level of force, an increase of force is associated with an increase in efficacy (r=0.33, p<0.01). Beyond this point, application of higher forces resulted in reduced efficacy (r=-0.49, p=0.03). As was calculated in this particular test this 'transition' level of force was 407.4 g. The absence of a correlation between brushing force and plaque removal efficacy suggests that in a 'user model' brushing situation, other factors than brushing force are of major influence on the amount of plaque removed.

Three-dimensional intravascular ultrasound assessment of plaque volume after successful atherectomy

The primary purpose of directional coronary atherectomy is the removal of intraluminal plaque. Angiography allows assessment of residual lumen narrowing but is limited in the assessment of residual plaque burden. Intravascular ultrasound has proven useful in assessing plaque size, but current use has been limited to a single, representative cross-sectional image rather than an evaluation of the entire plaque volume. To determine the volume of residual plaque after angiographically successful directional coronary atherectomy (≤20% residual stenosis), we performed intravascular ultrasound in 19 patients before and after atherectomy. Only coronary lesions optimal for three-dimensional analysis (a single, discrete stenosis in a nontortuous, non-calcified native coronary artery) were selected. A 2.9F sheath-design intravascular ultrasound catheter with a motorized pullback device was used in all patients. The cross-sectional area of the artery (defined by the medial-adventitia border), the lumen, and the plaque were measured at 1 mm intervals over a 15 to 20 mm segment, which included the target lesion and a proximal reference segment ( n = 362 cross-sections), before and after atherectomy. The volumes of the artery, vessel lumen, and plaque were calculated with a modified Simpson's equation and compared with standard area measurements at the point of maximal stenosis. After directional atherectomy there was no change in the volume of the artery, lumen, or plaque proximal to the target lesion. In contrast, there was a significant increase in luminal volume in the region of the target lesion (67.6 ± 25.7 mm 3 to 120.7 ± 47.7 mm 3; p = 0.01) because of a reduction in plaque volume (107.9 ± 28.2 mm 3 to 65.1 ± 10.6 mm 3; p= 0.01). On average, 39.7% (range 24% to 56%) of the target plaque volume was removed. The proportion of plaque removed did not relate to atherectomy catheter size or the ratio of catheter size to arterial or lumen size. Although a large percentage of target plaque volume remained, the average residual plaque volume (per millimeter of artery) was similar to the average plaque volume in the proximal reference segment ( p not significant). Two-dimensional analysis at the point of maximal stenosis tended to overestimate the effect of the atherectomy (51.7% vs 39.7% of the plaque removed; p < 0.05) because of an overestimation of plaque burden (79.4% of the vessel area vs 61.9% of the vessel volume; p < 0.05) but did provide an adequate postatherectomy assessment of the residual plaque and lumen. Directional coronary atherectomy increases lumen size by decreasing plaque volume without significantly changing arterial size. Despite apparent angiographically documented success, the majority of plaque volume remains after coronary atherectomy. Two-dimensional measurements of plaque, luminal, and arterial area at the site of maximal stenosis may overestimate the atherectomy effect but if appropriately selected can provide an adequate representation of the residual plaque.

Intracoronary ultrasound imaging before and after directional coronary atherectomy: In vitro and clinical observations

The rate of restenosis after directional coronary atherectomy (DCA) is higher than expected. To elucidate why, the current study used intravascular ultrasound (IVUS) imaging to investigate the mechanism of DCA. An in vitro validation study was performed to determine the accuracy of the measurement of plaque removal by IVUS. DCA was performed in eight human atherosclerotic artery segments. The volume of removed plaque was measured by water displacement and was compared with the volume calculated from IVUS images. A clinical study of DCA was performed in 32 lesions. IVUS was performed in 28 lesions after successful DCA. Measurements of lumen dimensions from digital angiograms before and after DCA were compared with observations of lumen and plaque size from the cross-sectional IVUS images. In the in vitro study, the mean plaque volume removed by DCA was 19.9 ± 8.5 μl. The calculated estimate of removed plaque volume by IVUS was 18.6 ± 7.9 μl and correlated closely with the volume by water displacement ( r = 0.92). The calculated volume of plaque removed from histologic sections was 14.3 ± 6.0 μl and was linearly correlated with plaque volume by water displacement ( r = 0.81). In the clinical study, the angiographic mean minimum lumen diameter increased from 1.0 ± 0.4 to 2.7 ± 0.5 mm and the percentage stenosis decreased from 70% to 19% ( p < 0.0001). The IVUS images before and after DCA showed that the lumen DCA improved from 2.9 ± 1.5 to 7.0 ± 1.5 mm 2 ( p < 0.0001). In addition the vessel cross-sectional area (CSA) increased from 17.1 ± 5.9 to 18.7 ± 5.5 mm 2. The atheroma CSA was reduced from 14.2 ± 5.0 to 11.7 ± 4.8 mm 2. This combined effect of reduction in atheroma CSA and stretching of the outer vessel diameter resulted in an improvement in percentage plaque area stenosis from 83% ± 7% to 61% ± 9%. It is concluded that despite a successful angiographic appearance, DCA removed an average of 2.5 mm 2 from the atheroma, which corresponds to only 18% of the atheroma CSA. The total lumen CSA increased 4.1 mm 2; 61% of the new lumen was created by cutting and removal of plaque, whereas 39% of the new lumen was made by stretching the external wall of the artery. Despite an excellent angiographic result, IVUS imaging reveals that after DCA a significant amount of residual atheroma remains. As in balloon dilatation, a stretching effect is a significant component of DCA.

730-3 “Directional” Coronary Atherectomy Removes Atheroma More Effectively from Concentric than Eccentric Lesions: Intravascular Ultrasound Predictors of Lesional Success

Directional coronary atherectomy (DCA) was developed to remove atheroma from eccentric lesions. Conventional teaching proposes that DCA is most effective for eccentric plaques; however, no data have correlated plaque configuration with atheroma removal. We performed intravascular ultrasound and angiography to assess the effect of plaque distribution and morphology on acute lesional success (percentage of plaque removed). We examined 101 target lesions and reference sites in 88 patients pre-and post-atherectomy. A core laboratory, blinded to outcome, classified lesions as concentric if plaque exceeded 0.75 mm in thickness for the entire 360° vessel circumference. Lesions with sparing of a portion of the vessel circumference (minimum plaque thickness &lt; 0.75 mm) were classified as eccentric. Other variables quantified by ultrasound included the presence and arc (in degrees) of vessel wall calcification. Angiographic lesion eccentricity and/or calcification did not correlate with percentage of plaque removed. The presence of ultrasound calcium decreased the percentage of plaque removed from 24.2% to 13.6%, p = 0.05. The arc of ultrasound calcification correlated inversely with plaque removal, r = 0.55. Most importantly: Ultrasound Plaque Distribution Concentric Lesions Eccentric Lesions p value Plaque Removed (mm 2 ) 4.66 2.43 0.003 Plaque Removed (%) 29.9 18.7 0.02 Adjunctive Balloon 56% 81% 0.05 Contrary to current doctrine, atherectomy achieves better plaque removal and requires adjunctive balloon less often in lesions with concentric, rather than eccentric, atheromata. Ultrasound target lesion calcification is a negative predictor of plaque removal.

Effect of a new pre‐brushing rinse on dental plaque removal

Non-prescription prebrushing rinses to facilitate dental plaque removal have been advertised in recent years. The purpose of the present study was to determine the plaque removal effectiveness of Plax (Colgate) prebrushing rinse by comparing it to a placebo solution. 19 dental students volunteered for this double blind study which consisted of 2 experimental periods. The following procedure was followed: 3 weeks after scaling and polishing, the participants abstained from oral hygiene for 3 days to allow dental plaque to accumulate. After plaque disclosing, the 4 mandibular incisors were photographed using a strictly defined technique, as described by Quirynen et al. Then the volunteers mouthrinsed for 30 s with 15 ml of a solution provided to them. Neither the volunteers nor the examiners knew which solution (test or control) was used. After mouthrinsing, the participants were allowed to brush their teeth and the remaining plaque was photographed again. During the 2nd experimental period, the same procedure was followed, and the 2nd solution was used for mouthrinsing. The effectiveness of the solutions was evaluated by comparing the proportion of dental plaque removed during the 2 experimental periods. The area of dental plaque was measured by an electronic high-precision device (planimeter). The proportion of plaque removed after rinsing with Plax was 0.40 +/- 0.23 and after rising with placebo 0.42 +/- 0.24, of the tooth surface (p = 0.962). Analysis of data by means of paired t-test between the 2 experimental periods revealed no beneficial effect regarding plaque removal when Plax was used.

A comparison of three methods for estimating dental plaque removal from individual teeth

The purpose of this study was to determine the efficiency of dental plaque removal, in vitro, by physical force. Of the 3 methods used, turbidity was the most sensitive for measuring microgram amounts of plaque. Air-dried weight and dental plaque imprint assays (DPIA) complemented turbidity measurements by providing a weight standard and a new method for visualizing plaque bacterial structure before the stained imprint was transformed into numerical data. The amount of dental plaque removed from a tooth by physical force can be measured and described as a percentage of the total removable plaque on that tooth.

Self-application of topically applied stannous fluoride: a feasibility study

If the cariostatic effects of topically ap­ plied stannous fluoride depend on plaque removal, self-prophylaxis is as beneficial as technician-applied prophylaxis. Some subjects cleaned their own teeth in this study. Others had their teeth cleaned by dental technicians. All used SnFg. The amount of plaque removed in all groups, those brushing their own teeth and those whose teeth were cleaned by the tech­ nicians, was about the same. Apparently, the patient can perform the first step of the three-agent SnF2 method, thereby saving the dentist’s time and allowing more people to enjoy the benefits of pre­ ventive dentistry.