Biofilm: a new view of plaque.

Dental researchers have attempted to understand the microbial nature of oral diseases over the past 120 years. Their view of plaque and its constituent microorganisms has shifted from a specific plaque hypothesis to a non-specific plaque hypothesis and back again to a theory of specific periodontal pathogens in plaque. Changes in the way plaque and its microorganisms are viewed affect the strategies used to prevent and control periodontal diseases. In recent years, dental researchers have begun to view plaque as a biofilm. This shifting view of plaque has important implications for future efforts in prevention and treatment. This article describes the various ways that dental professionals have viewed plaque throughout the years highlighting the current view of plaque as a biofilm and the ramifications for periodontal therapy.

An investigation of dental hygiene treatment fear.

PURPOSE: The purpose of this study was to develop and test the psychometric properties of a dental hygiene fear survey in a convenience sample population from a Midwestern metropolitan area. METHODS: A convenience sample of 300 subjects from two sites, a suburban general dental practice and a dental school intramural faculty practice located in a metropolitan area, was utilized. A 16-item instrument was developed that incorporated the University of Washington Fears Clinic four subtypes of dental fear: fear of specific stimuli, generalized anxiety, distrust, and catastrophe. The survey was administered prior to dental hygiene treatment. Scores were summed and patients were classified as experiencing dental hygiene fear if their scores were greater than one standard deviation above the mean. Reliability was estimated by Cronbach's alpha. Validity was examined by correlating the revised instrument with measures of conceptually related variables. RESULTS: Cronbach's alpha coefficient was .85 for specific dental hygiene stimuli, .79 for generalized anxiety, .75 for distrust, and .68 for fear of catastrophe while receiving dental hygiene treatment. Overall reliability of all 16 items was estimated at .92. A significantly positive correlation (.58) was found between dental hygiene patients who reported high fear and avoidance (> 2 years) of dental hygiene treatment (p < .05). Dental hygiene fear correlated negatively (-.12) with age (p < .05). Females reported dental hygiene fear more frequently than males. CONCLUSIONS: Further revisions of the Dental Hygiene Fear Survey are needed; however, this survey shows promise in evaluating dental hygiene fear.

The effect of personal protective equipment on high-and low-dental fear patients.

PURPOSE: This investigation was designed to examine both high- and low-dental-fear patients' perceptions about and anxiety responses to personal protective equipment (PPE) as presented in a videotaped, simulated interaction between oral healthcare worker and patient. METHODS: Sixty-two individuals representing a convenience sample presented at the University of Missouri-Kansas City (UMKC) Dental School and were screened for eligibility. The Dental Fears Survey was administered to participants to assess level of dental fear. Subjects were then matched according to fear level, gender, and age, and randomly assigned to an experimental or control group. Subjects viewed a videotaped vignette of a male dentist conducting a new patient interview. The control group viewed a tape in which the provider did not utilize PPE. The experimental group viewed the provider putting on PPE at completion of the interview. Subjects were instructed to complete a semantic differential scale at completion of the tape in order for the researchers to assess their attitude toward the scene. Paired adjectives in the semantic scale were scored from 1 to 7, with low scores reflecting negative evaluations and high scores reflecting positive evaluations. Heart rate and skin conductance were measured prior to and during the viewing of the videotapes by means of a photoplethysmograph and an electrodermograph, respectively. RESULTS: A two-factor ANOVA found the main effect of fear to be significant (p < .05), with subjects exhibiting high levels of dental fear rating both videotapes (PPE & NO PPE) more negatively than subjects exhibiting low levels of dental fear. A repeated measure ANOVA was used for analysis of heart rate and skin conductance. The Dunn's Multiple Means Comparison Test showed that skin conductance increased significantly (p < .05) in both groups from baseline to presentation of the oral healthcare environment. CONCLUSIONS: A videotaped presentation of the dental environment produced significantly more negative evaluations from patients with high fear than from patients with low fear. Both groups experienced a significant increase in skin conductance (perspiration) upon presentation of the oral healthcare environment. However, presence of PPE did not adversely affect patient perceptions of the oral healthcare provider.

Effectiveness of antimicrobial mouthrinses on aerosols produced by an air polisher.

PURPOSE: The purpose of this examiner-blind investigation was to study the effect of two antimicrobial mouthrinses on the quantity and potential respiratory-penetrating ability of microorganisms generated by an air-abrasive polisher. METHODS: Forty-five adult subjects were randomly assigned to one of three groups and asked to rinse for 30 seconds with 15 ml of either a 0.12% chlorhexidine rinse, an essential oil mouthrinse, or water prior to air polishing. Prior to treatment, microbes in ambient air were collected for five minutes using an Andersen air sampler. This device simulates the human respiratory system and collects airborne microbes by means of blood agar plates stacked in a cascade impact system. Bacteria found at stages two, four, and six--representing the pharynx, bronchi, and alveoli-were collected and counted in this study. During three minutes of air-abrasive instrumentation and two minutes immediately following, airborne microbes were again collected. Agar plates removed from the sampler were incubated for 24 hours at 37 degrees C. Colony-forming units per cubic foot of air (CFUs/ft(3)) were enumerated using a Lab Line colony counter. Data were analyzed using a two-factor repeated measure ANOVA and Dunn's multiple mean comparison techniques. RESULTS: Results showed no significant effect of prerinsing among treatment groups. An increase in CFUs/ft(3) was found at each sequential stage of the air sampler, resulting in a statistically significant within-group effect (p< or =.05). Additionally, a significant interaction was found between prerinse treatment and respiratory stage (p< or =.05) . CONCLUSION: While the air-abrasive polisher produced significant amounts of deeply penetrating bacterial aerosol, differences in CFUs/ft(3) generated following the antimicrobial prerinsing tested are of little clinical significance.

Aerosol generation by two ultrasonic scalers and one sonic scaler. A comparative study.

The purposes of this study were to compare the amount of aerosols generated from ultrasonic and sonic scalers and to measure the potential depth of respiratory tract penetration. Forty subjects were randomly assigned to receive instrumentation with the magnetostrictive, piezoelectric, or air turbine scaler. The Anderson Air Sampler collected total baseline airborne microbes for 20 minutes prior to treatment and for 20 minutes during instrumentation. This cascade impactor system measures the degree of microbial penetration in a simulated respiratory system. Blood agar plates from the sampler were incubated for 24 hours at 37 degrees C. Colony forming units per cubic foot of air (CFUs/cu. ft.) were enumerated by one blind examiner using a Lab Line Colony Counter. Data for total microbial CFUs/cu.ft. and CFUs/cu.ft. by sampler level were analyzed on the log-transformed data using ANCOVA. Baseline values of airborne bacteria served as the covariate. Results showed no significant difference in mean combined total CFUs/cu.ft. for the magnetostrictive, piezoelectric, or air turbine sonic scalers. The magnetostrictive scaler generated the lowest CFUs/cu.ft. at the deepest level of penetration; however, no significant difference in level of penetration was found among the three scalers.

Effectiveness of chlorhexidine and sodium fluoride in reducing dentin hypersensitivity.

This investigation was conducted to evaluate the effect of chlorhexidine, sodium fluoride, and sequential rinses of chlorhexidine (Cx) and sodium fluoride (NaF) on dentin hypersensitivity. Forty-four adult patients with dentin hypersensitivity on three teeth were randomly assigned to receive one of four treatment rinses: (1) placebo; (2) 0.12% Cx; (3) 0.2% NaF; or (4) 0.12% Cx plus 0.2 NaF. Patients' responses to cold stimulation were recorded at baseline, two weeks, and four weeks. Pain response was quantified by applying successively decreasing temperature intervals of water (20 degrees C, 15 degrees C, 10 degrees C, 5 degrees C, and 0 degrees C) to exposed dentin. Plaque Index (Silness and Löe) was recorded at baseline only. Data on dentin sensitivity over time were analyzed using a repeated measures ANOVA. This ANOVA was conducted to generate an error term for calculation of Dunn's multiple mean comparison test. A Spearman rank order test was computed to assess correlation between plaque and hypersensitivity at baseline. Results showed the Cx and NaF rinses alone significantly reduced hypersensitivity (p less than .01) at four weeks compared to baseline. Sequential Cx and NaF rinses significantly decreased sensitivity (p less than .01) at both the two- and four-week intervals compared to baseline. At the four-week interval, the sequential Cx/NaF rinse group showed a significantly greater reduction (p less than .01) in hypersensitivity response when compared to placebo. Cx alone, or NaF alone groups. A moderate, positive correlation (r = 0.55) was demonstrated between plaque and dentin hypersensitivity. This was statistically significant at the (p less than .05) level.

The effectiveness of a patient-applied tooth desensitizing gel. A pilot study.

Potassium nitrate has been found to be an effective ingredient for reducing dentinal hypersensitivity. The purpose of this study was to evaluate the effectiveness of a patient-applied 10% potassium nitrate glycerine-based gel in decreasing dentinal sensitivity on cold on teeth with exposed dentin apical to the cemento-enamel junction, 12 patients, each having 3 hypersensitive teeth, were tested. The patients were divided into 3 treatment groups: group 1 was treated with a glycerine-based 10% potassium nitrate gel: group 2 was treated with a glycerine gel without potassium nitrate; and group 3 received no gel and no treatment (control). Following brushing and flossing, groups 1 and 2 applied the gel to the test teeth using custom-made soft acrylic trays, for a period of 5 min/day for 4 weeks. Patient responses to cold water stimuli of 20 degrees C, 10 degrees C and 0 degrees C, were measured at baseline (week 0), then at 1-, 2-, 3- and 4-week intervals. Group 1 patients showed a significant decrease in sensitivity to cold at week 2 only. The group 2 patients showed a significant decrease in sensitivity to cold after 3 and 4 weeks. A statistically significant decrease in sensitivity was noted between group 2 and group 3 patients at week 3. The most sustained decrease in sensitivity to cold was found on teeth treated with plain glycerine.

Assessment of curette sharpness.

Nothing to date has appeared in the literature addressing the relationship of specific bevel dimension and clinical sharpness of curette blades. This study investigated the degree of clinical sharpness of Gracey curettes following four periods of simulated root planning and, using the scanning electron microscope (SEM), determined the approximate number of strokes at which loss of clinical sharpness became apparent. Seventy-five new stainless steel curette blades were standardized and randomly assigned to one of five groups: control, 30-stroke, 50-stroke, 70-stroke, and 90-stroke. With the exception of the control group, blades underwent a simulated root-planing procedure, on extracted, periodontally involved teeth, which employed a device to standardize pressure and stroke length. Blades were then tested for clinical sharpness using light reflection, with two degrees of magnification; and plastic stick, a tactile evaluation. Blades were photographed under the SEM at a magnification of x1,000. Bevel width was measured at 10 standardized locations on the photomicrographs, and a mean was calculated. Nonparametric data were analyzed using the Kruskal-Wallis statistical test and SEM parametric data using ANOVA and post hoc Newman-Kuels tests. Results showed no significant differences among treatment groups when either tactile or magnification sharpness tests were used. Analysis of the SEM data showed no statistically significant differences among bevel dimensions for any of the five groups. A Spearman rank order correlation, used to compare the clinical data to the SEM bevel measurements, showed no correlation of clinical sharpness and SEM-determined bevel dimension.