Pulsed ultrasound modulated optical tomography utilizing the harmonic response of lock-in detection.

Ultrasound modulated optical tomography (USMOT) can image the optical properties of a scattering medium at a spatial resolution approaching that of ultrasound (US). A lock-in parallel speckle detection technique is proposed to detect pulsed US modulated light using a multipixel detector. The frequency components of the pass band match those of the US pulse train and provide efficient detection. The modulation depth is extracted by taking the difference between a pair of speckle patterns modulated by a pair of phase-inversed US bursts. Modification to pulse inversion mode enables the second harmonic US modulation due to nonlinear US propagation to be detected.

Longitudinal acoustic properties of poly(lactic acid) and poly(lactic-co-glycolic acid).

Acoustics offers rich possibilities for characterizing and monitoring the biopolymer structures being employed in the field of biomedical engineering. Here we explore the rudimentary acoustic properties of two common biodegradable polymers: poly(lactic acid) and poly(lactic-co-glycolic acid). A pulse-echo technique is developed to reveal the bulk speed of sound, acoustic impedance and acoustic attenuation of small samples of the polymer across a pertinent temperature range of 0-70 °C. The glass transition appears markedly as both a discontinuity in the first derivative of the speed of sound and a sharp increase in the acoustic attenuation. We further extend our analysis to consider the role of ethanol, whose presence is observed to dramatically modify the acoustic properties and reduce the glass transition temperature of the polymers. Our results highlight the sensitivity of acoustic properties to a range of bulk properties, including visco-elasticity, molecular weight, co-polymer ratio, crystallinity and the presence of plasticizers.

Clinical effectiveness and soft tissue compatibility of a temporary restorative material.

OBJECTIVE: The purpose of this six-week study was to evaluate in vivo the effectiveness of Systemp.inlay as a temporary restorative material. METHOD: Subjects with the proper indication for a class II restoration were entered into the study. Twenty-three subjects and twenty-nine temporary restorations were evaluated at time of placement, three and six weeks. Two faculty members were calibrated to evaluate the material. Following the six-week trial, the temporary restorative material was removed and the test teeth were restored with a definitive restorative material. RESULTS: The temporary restorative material provided mechanical and anticariogenic protection of tooth structure while preventing dental sensitivity and patient discomfort. It promoted soft tissue health as evidenced by the enhanced plaque and gingival indices found associated with the temporarily restored teeth. Its ease of placement and removal makes it an attractive alternative for the dental practitioner. The change in color of the material over the six-week duration of the study may limit its use to posterior teeth and to lingual/palatal surfaces of anterior teeth. CONCLUSION: Ease of placement and removal and retention of the temporary restorative material were extremely good. Marginal and surface integrity of the material was maintained and no or minimal sensitivity was reported throughout the study. The material did not promote the accumulation of plaque nor result in gingival inflammation. The color change noted was not of clinical importance. Therefore, this temporary restorative material was demonstrated to be clinically effective in Class II cavity preparations.

Investigation of vacuum pumping on the dose response of the MAGAS normoxic polymer gel dosimeter.

The effect of vacuum pumping on the dose response of the MAGAS polymer gel dosimeter has been investigated. A delay of several days post-manufacture before irradiation was previously necessary due to the slow oxygen scavenging of ascorbic acid. The MAGAS polymer gel dosimeter was vacuum pumped before gelation to remove dissolved oxygen. The MAGAS polymer gel dosimeter was poured into glass screw-top vials, which were irradiated at various times, post-manufacture to a range of doses. Magnetic resonance imaging techniques were used to determine the R2-dose response and R2-dose sensitivity of the MAGAS polymer gel. The results were compared with a control batch of MAGAS polymer gel that was not vacuum pumped. It was shown that vacuum pumping on the MAGAS polymer gel solution immediately prior to sealing in glass screw-top vials initially increases the R2-dose response and R2-dose sensitivity of the dosimeter. An increase in the R2-dose response and R2-dose sensitivity was observed with increasing time between manufacture and irradiation. Over the range of post-manufacture irradiation times investigated, the greatest R2-dose response and R2-dose sensitivity occurred at 96 hours.

A clinical comparison of 2 electric toothbrush designs.

A single blind 30 day study compared the reduction of plaque and gingivitis for the Hapika Powerbrush to the Interplak ultra 10 tuft. A longitudinal parallel group design was utilized and screening evaluation was performed to determine patient eligibility prior to study enrollment, 66 subjects were entered into the study and assigned to 1 of 2 groups, each using one of the toothbrushes. At baseline, subjects received an oral soft tissue exam, a dental hard tissue exam, and were scored by the Lobene modification of the Löe and Silness gingival index (GI). Plaque was then disclosed and scored both pre and post brushing using the modified Turesky plaque/debris examination and an interproximal bleeding examination was performed post-brushing. On days 15 and 30, after an oral soft tissue and GI examination, plaque was graded by the Modified Turesky plaque/debris exam. Subjects then brushed and were graded by the Modified Turesky plaque/debris examination and an interproximal bleeding index examination. The results showed that both brushes provided a similar change in clinical indices. All produced a statistically significant reduction from baseline to day 30 for the gingival index (26.5-29.1%), the bleeding index (13.8-24.1%), and the plaque index (16.9-19.4%). A comparison of pre and post brushing scores for the plaque index at 30 showed that both brushes reduced plaque similarly with a statistically significant reduction (P < 0.05) from their pre-brushing plaque index scores at all time periods.

A microbiological and clinical study of the safety and efficacy of baking-soda dentifrices.

This article reports the results of a study that examined the clinical and microbiological changes associated with regular use of baking-soda dentifrices. Two dentifrice formulations were examined in a 6-month longitudinal study of 101 adult subjects with assessments for plaque, gingival inflammation, and stain at baseline and 3 and 6 months during the active phase of the study, and at 3 months after cessation of product use. One dentifrice contained 52% baking soda and 3% sodium percarbonate (Arm & Hammer PeroxiCare) while the other dentifrice contained 65% baking soda (Arm & Hammer Dental Care). Both dentifrices resulted in statistically significant reductions in dental plaque, gingival inflammation, and stain at all time periods compared to baseline. Dental plaque and buccal soft-tissue samples were obtained for microbiological analysis from a 50-subject subset. Microbiological assays, including bacterial culture, phase-contrast microscopy, and immunofluorescence microscopy, confirmed the safety of both formulations. Beneficial alterations in dental plaque bacteria were noted, including significant reductions in the levels of Actinomyces species. The data from this study indicate that dentifrices containing high levels of baking soda are clinically effective and microbiologically safe.

Clinical evaluation of the effect of a hydrogen peroxide mouth rinse, sodium bicarbonate dentifrice, and mouth moisturizer on oral health.

The objective of this 60-day single-blind, parallel trial, using 150 subjects, was to evaluate the effect of a 20% sodium bicarbonate dentifrice, a 1.5% hydrogen peroxide solution and a mouth moisturizer on oral tissues and microflora. Subjects were randomly assigned to one of five groups. The treatments were: 1) Sage dentifrice (sodium bicarbonate). Toothette Plus containing baking soda saturated with the hydrogen peroxide solution and use of a mouth moisturizer, 2) Crest dentifrice, Toothette Plus containing baking soda saturated with the hydrogen peroxide solution and use of a mouth moisturizer, 3) Crest dentifrice, Toothette Plus containing baking soda with a control solution and no mouth moisturizer, 4) Crest dentifrice, Toothette (without baking soda), saturated with a control solution and no mouth moisturizer, and 5) Crest dentifrice, Toothette saturated with 1.5% flavored H2O2 and no mouth moisturizer. From a subgroup of 35 patients (seven from each group) buccal smears for exfoliative cytology were taken as were supragingival microbiological samples from the mesial aspect of first molars (pooled). Buccal smears were evaluated for signs of histopathological changes. Microbiological samples from supra- and subgingival plaque for P. gingivalis, P. intermedia, A. actinomycetemcomitans. A viscosus, F. nucleatum, F. sanguis and C. albicans were evaluated. Clinical parameters measured were a stain index (SI), the modified gingival index (MGI), and a plaque index (PI). There were no adverse changes in the oral microflora and no anaplastic or other pathological changes in any subjects. Clinical parameters showed a statistically significant reduction in the MGI ranging from 26.7-29.9% with no significant differences among the groups (p > 0.05). The PI showed small reductions in all groups except group 2, but the differences were not statistically significant from each other or baseline (p > 0.05). The SI revealed slight increases in all groups and no differences among the groups. It can be concluded that use of Sage dentifrice, Toothette Plus saturated with Perox-A-Mint and Sage Mouth Moisturizer are safe to oral tissues. Using these components did not result in clinically noticeable stain formation, promote plaque formation, or produce any significant adverse changes in the oral microflora.

A microbiological and clinical study of the safety and efficacy of baking-soda dentifrices.

This article reports the results of a study that examined the clinical and microbiological changes associated with regular use of baking-soda dentifrices. Two dentifrice formulations were examined in a 6-month longitudinal study of 101 adult subjects with assessments for plaque, gingival inflammation, and stain at baseline and 3 and 6 months during the active phase of the study, and at 3 months after cessation of product use. One dentifrice contained 52% baking soda and 3% sodium percarbonate (Arm & Hammer PeroxiCare) while the other dentifrice contained 65% baking soda (Arm & Hammer Dental Care). Both dentifrices resulted in statistically significant reductions in dental plaque, gingival inflammation, and stain at all time periods compared to baseline. Dental plaque and buccal soft-tissue samples were obtained for microbiological analysis from a 50-subject subset. Microbiological assays, including bacterial culture, phase-contrast microscopy, and immunofluorescence microscopy, confirmed the safety of both formulations. Beneficial alterations in dental plaque bacteria were noted, including significant reductions in the levels of Actinomyces species. The data from this study indicate that dentifrices containing high levels of baking soda are clinically effective and microbiologically safe.

Clinical effects of a stannous fluoride mouthrinse on plaque.

The purpose of this 3-week, double-blind study was to determine the effect of a stannous fluoride-containing mouthrinse on existing and developing dental plaque. A total of 55 subjects (mean age = 31.42 yrs.) received a professional prophylaxis in randomly assigned contralateral quadrants and were then stratified into two balanced groups based on screening plaque scores: one group (27 subjects) used the placebo rinse, the second group (28 subjects) used the test mouthrinse (0.63% diluted to 0.1% stannous fluoride). Plaque index (PI) and stain index (SI) were scored at baseline, week 1 and week 3. Gingival inflammation (GI) was monitored as a measure of product irritancy potential. The PI for the stannous fluoride rinse was significantly lower than the placebo, (p < 0.0001), for both prophied and unprophied sites with an average reduction of 29% at week 1 and 28% at week 3. There was no statistically significant difference between the presence or absence of prophylaxis. Plaque indexes for both stannous fluoride and placebo showed significant reduction (p < 0.0001) compared to baseline in all sites. Differences in staining potential between stannous fluoride and placebo were not significant (p > 0.05) at any time during the study. The stain index for both stannous fluoride and placebo showed a non-significant increase from baseline in the prophied and unprophied sites. No irritancy was noted, although a trend towards lower GI scores was observed at 3 weeks for the stannous fluoride group.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of vitamin E gel, placebo gel and chlorhexidine on periodontal disease.

The purpose of this study was to compare the effects of a topical 5% vitamin E gel, a placebo gel and chlorhexidine on established and developing plaque and periodontal disease in 48 adult subjects. Baseline data included Plaque Index, Gingival Index and periodontal probing depth. All data were collected by a single calibrated examiner using a double-blind methodology. One group of subjects applied 12 mL of a vitamin E-containing gel delivering 800 mg of alpha-tocopherol, another applied 12 mL of a placebo gel, and the final group rinsed with 0.5 oz of 0.12% chlorhexidine gluconate. After two weeks, the clinical data were again recorded, and two quadrants were randomly selected and treated by root planing and scaling, with data collection repeated after both 4 and 6 weeks. Our results indicated that no significant effects upon plaque or gingivitis were obtainable in either the placebo or the vitamin E groups. However, use of 0.12% chlorhexidine significantly reduced plaque. These results do not support the use of vitamin E as a topical chemotherapeutic agent for the control of gingivitis or periodontal disease.

A clinical comparison of two electric toothbrushes with different mechanical actions.

The purpose of this study was to compare the effectiveness of plaque removal of the Water Pik Automatic Toothbrush and Interplak brush versus the Oral B-40 manual brush. Thirty healthy patients having plaque on all tooth surfaces were admitted for this two-week, double-blind study. Patients served as their own control by brushing manually for one week, and then for a second week with a randomly-assigned electric brush. Three plaque indexes were scored at baseline, one week and two weeks. For all these indexes, results showed that the Water Pik Automatic Toothbrush removed significantly more plaque than manual brushing. The Interplak brush removed statistically more plaque than manual brushing only with the Turesky Index. The data for all indexes have a trend toward better plaque scores for patients who used the Water Pik Automatic Toothbrush. However, statistical analysis of these scores showed that both electric toothbrushes performed equally well.

Effect of a chemotherapeutic agent delivered by an oral irrigation device on plaque, gingivitis, and subgingival microflora.

Sixty-six adults were examined in a double-bind study which examined the effect of an antimicrobial agent delivered by an oral irrigating device. Each subject received a randomized half mouth dental prophylaxis. The Gingival Index, gingival crevicular fluid volume, Plaque Index, Modified Papillary Bleeding Index, probing pocket depth, and probing attachment levels were determined at baseline, 3 weeks, and 6 weeks. The composition of the subgingival microflora in the prophied and non-prophied quadrants was examined by phase contrast microscopy and by immunofluorescence. This study demonstrates that an antimicrobial product delivered by an oral irrigating device could result in significant reductions in plaque, bacterial cell counts, and gingival bleeding and may, therefore, be an effective adjunct to normal oral hygiene.

The effect of an antimicrobial mouthrinse on early healing of gingival flap surgery wounds.

A randomized double-blind crossover design study using 25 patients requiring bilateral gingival flap surgery was completed. The effect of rinsing postsurgically three times daily with an antimicrobial mouthrinse or physiological saline on dental plaque formation, gingival inflammation, bleeding, wound healing, and patient comfort was evaluated at 7, 14 and 28 days. The antimicrobial rinse was statistically significantly 28.9% more effective than saline at seven days for reducing plaque. It was also significantly more effective for improving wound healing at day 7 as measured by edema (p less than 0.04). There were no significant differences in gingival index scores or bleeding at any time period. Use of an antimicrobial mouthrinse may be an effective aid in early healing of gingival flap surgery wounds.

The application of a collagen stabilizer to the gingiva of the beagle dog. Effect on ligature-induced periodontal disease.

The objective of this study was to determine the effect of crevicular application of a collagen stabilizer on ligature-induced periodontal disease in beagle dogs. Fourteen male and female dogs, 15 months of age, were studied. The mandibular first molars and third and fourth premolars were ligated for 6 months and moderate periodontitis resulted. Ligatures were removed for 2 months and then replaced for an additional 3 months to experimentally mimic the episodic changes seen in human periodontal disease. Following this phase, ligatures were removed and the animals were assigned to a placebo or treatment group. Medications were then applied intracrevicularly, three times a week over 5 months using an IMAX irrigator. Clinical indices measured were plaque index (PI), gingival index (GI), gingival crevicular fluid flow (GCF), attachment level (AL), pocket depth (PD) and standardized radiographic analysis of alveolar bone height. While overall changes in PI, GI and GCF were not significant, the results showed that alveolar bone regeneration was increased approximately twice as much in the treatment group as compared to the placebo group, PD improved by 20% vs. 12.5% (P less than 0.001) and AL improved by 8.8% vs. 4.5% (P less than 0.001). The data were also evaluated in terms of the response in more severe sites as compared to those less severe. The results of these evaluations showed the more severe sites to be significantly more responsive to treatment than the less severe sites.(ABSTRACT TRUNCATED AT 250 WORDS)

An evaluation of minocycline in patients with periodontal disease.

The purpose of this study was to determine the passage into and concentration of Minocycline HCl (Minocin) in gingival crevicular fluid (GCF) and the relationship between its concentration of saliva. GCF, serum and changes in periodontal health. Over an 8 day period, 10 adults with periodontal disease received orally 200 mg/day of Minocin and 10 other received 150 mg/day. The parameter evaluated included the DMF, gingival index, plaque index, crevice depth, oral soft tissue evaluation. SMA-12, CBC, prothrombin time, and concentrations of Minocin in serum, saliva and GCF. The DMF score, crevice depth, SMA-12, CBC and prothrombin time were determined on days 1 and 8. All other parameters were evaluated on days 1, 2, 3, 5 and 8. The results of this study showed that Minocin administration resulted in no significant changes in blood chemistry, blood counts and prothrombin time, was effective against oral microorganisms as shown by reductions in plaque scores, produces an improvement in gingival health, is present in serum at therapeutically effective levels when given in doses of either 200 mg or 150 mg per day and is concentrated in gingival crevicular fluid at levels 5 times as high as serum.

The effect of a quaternary ammonium-containing mouthwash on formed plaque.

The effect on formed dental plaque of a commercial mouthwash containing cetylpyridinium chloride (CPC) was evaluated in forty-one adults. During this fourteen day study no oral hygiene other than the use of a mouthwash was provided. Plaque and gingival indices were scored on sixteen teeth at days 0, 7 and 14. The results of this study suggested that subjects using the CPC containing mouthwash formed less plaque than those using the placebo mouthwash. No change in the Gingival Index was observed. Of those patients using the CPC containing mouthwash, four showed a slight staining of the anterior teeth and five reported a mild burning sensation of the tongue.

Clinical evaluation of a quaternary ammonium-containing mouthrinse.

This was a double-blind, radomized, crossover study of adult subjects to evaluate the effect of a test mouthrinse (Cepacol) on plaque accumulation. The study was divided into two parts, four weeks each, one in which only a mouthwash was used (part I) and the other in which a mouthwash and toothbrushing were used (part II). 1. The test mouthrinse produced a satistically significant reduction in dental plaque when compared to a placebo rinse. 2. The GI averaged approximately 1.0 throughout the study regardless of which mouthrinse was used. 3. A possible carryover effect of the test mouthrinse was noted. 4. A lower plaque score was seen in 67 to 75% of all patients during the period in which the test mouthrinse was used as compared to the placebo. 5. Ten subjects reported a burning sensation of the tongue with the test mouthrinse. No objective adverse effects were seen.