Effect of Aerva sanguinolenta (Lal bishalyakarani) plant extract on biofilm-induced human enamel demineralization: An in vitro study.

BACKGROUND: Controlling cariogenic biofilm formation by plant extracts could add to preventive strategies to dental caries. OBJECTIVE: To evaluate in vitro the role of Aerva Sanguinolenta ethanolic extract on biofilm-induced microbial human enamel demineralization. METHODOLOGY: The prepared enamel sections of study group (SG), positive control group (PCG), and negative control group (NCG) were immersed in 2 ml of 0.2% ethanolic extract of A. sanguinolenta, 0.12% chlorhexidine, and distilled water, respectively, for 2 min before subjecting to closed batch culture technique utilizing mono- or dual-species culture media of Streptococcus mutans and Lactobacillus acidophilus. Quantification of biofilm and demineralization of enamel was performed by crystal violet (CV) assay and scanning electron microscope (SEM) attached to energy-dispersive X-ray analysis, respectively. STATISTICAL ANALYSIS: Two-way ANOVA and Tukey's test were used for analysis. RESULTS: CV assay of biofilm recorded the highest and lowest optical absorbance value in NC3 (2.728660) and PC3 (0.364200), respectively. Thus, biofilm formation is highest in NCG and lowest among PCG. Surface roughness and porosity in enamel are greatest among NCG and lowest among SG as evident by SEM. Wt% of calcium (S3 47.7170) and phosphorus ion (S3 22.7330) was highest in SG, closely resembling that of B enamel (Ca = 41.9530, P = 19.6650). Wt% of oxygen is lowest in SG (S3 28.8920) and resembles baseline O2 (37.4950). Thus, the amount of biofilm formation is moderate and amount of demineralization of enamel is least among SGs. CONCLUSION: Enamel exposed to 2 ml of 0.2% solution of A. sanguinolenta for 2 min could fairly inhibit formation of biofilm and positively inhibit underlying demineralization in cariogenic environment.

Profilometric analysis of root surfaces after using various polishing agents.

BACKGROUND: Polishing is an important step in oral prophylaxis procedure which retards further accumulation of plaque on the root surfaces. Though polishing was done with various abrasive particles with different sizes over a long period of time, it was never been highlighted to evaluate the ideal polishing material and the particle size that would produce the ideal surface smoothness (Ra <0.2 µm). MATERIALS AND METHODS: The present study was carried out on 70 periodontally involved, caries-free extracted human teeth from 42 patients. All the teeth were collected from the region of incisors, canines, and premolars. In vitro scaling and root planing were performed by piezoelectric scaler and Gracey's area specific curettes, respectively. All the teeth were grouped at random into control and experimental. The collections of abrasive materials were done directly from the market, and the different particle sizes were prepared in the laboratory. EXPERIMENTATION: The polishing was done at a constant speed of 200 rpm with cylindrical nylon bristle brush followed by rubber prophy cup. Each group belonging to control and experimental was subjected to profilometric study for evaluation of surface roughness. RESULTS: Regular polishing abrasives are not able to produce the surface smoothness of our desire level (i.e., Ra <0.2 µm), which can be achieved only by submicron-sized particles. CONCLUSION: Regular size polishing particles available in the market (>5 µm) are not able to produce the surface smoothness <0.2 µm. Only, submicron sized particles are able to produce the desired smoothness.

A clinical study on the efficacy of hydroxyapatite - Bioactive glass composite granules in the management of periodontal bony defects.

BACKGROUND: In periodontal regeneration, several alloplastic materials are being used with a goal to reconstruct new osseous tissue in the infrabony defect sites. The present study was undertaken to evaluate the efficacy of hydroxyapatite-bioactive glass (HA:BG) composite granules in the management of periodontal bony defects. MATERIALS AND METHODS: A randomized control study was conducted. Subjects with infrabony defects were divided into three groups. Test Group 1 (n = 10): Defect site was treated with HA:BG, with a biodegradable membrane. Test Group 2 (n = 10): Defect site was treated with HAP, with a biodegradable membrane. Control group (n = 10): Defect site was treated with open flap debridement with a biodegradable membrane. RESULTS: The healing of defects was uneventful and free of any biological complications. The gain in clinical attachment level, reduction of probing pocket depth, and defect fill were statistically significant in all three groups. TG1 sites showed significant defect fill than TG2 and CG sites. CONCLUSION: The performance of HA:BG was better compared to HAP and open flap debridement for the reconstruction of infrabony defects.

In vivo bone response and interfacial properties of titanium-alloy implant with different designs in rabbit model with time.

BACKGROUND: Using implants for dental applications are well-accepted procedures as one of the solutions for periodontal defect repair. Suitable design and materials, their reaction with the surrounding hard tissues and interfacial biomechanical properties are still considered to be the primary criteria which need to be addressed systematically. In the present study, a thorough and systemic approach was made to identify a suitable implant, considering the above criteria after both in vitro and in vivo animal trials. MATERIALS AND METHODS: Titanium alloy (Ti-6Al-4V) implants, with thread and without thread models, were implanted to the mid-metaphysial portion of the tibia of the right hind leg of three white Australian Chinchilla rabbit species and their effects and response to the surrounding bone were investigated. Parameters studied included hematological and biochemical features (serum alkaline phosphatase and calcium), both preoperatively and postoperatively, consecutively for 7 days and after 1-3 months. The interfacial integrity and compositional variation along the interface were studied using scanning electron microscope (SEM) with energy dispersive analysis of X-ray (EDAX) and histopathology from 1 to 3 months consecutively. Finally, biomechanical properties were studied with the help of push-out test. RESULTS: Bone remineralization started through the process of electro-physiological ionic exchanges, which helps in formation of osteoblastic cells in the area of bony injury. The SEM-EDAX results confirmed the initial stability for the Ti (with thread) implant, but the regeneration of new bone formation was faster in the case of Ti (Without thread) implant, and hence could be used for faster healing. These have also been substantiated through push-out and histopathlogical tests. CONCLUSION: From the physico-chemical and biomechanical observations, it was found that that smooth type implants were well accepted in the physiological condition although chances of elemental leaching from the surface were also observed. Increase of the surface roughness can help into the formation of physico-chemical bondage with the surrounding hard tissues.

Spectral characteristics of a binary dye-mixture laser.

We have investigated laser action in a binary mixture of dyes, Rh-6G and DCM, resulting in tunable laser emission over an extended frequency region. The two dyes absorb the same pump radiation but fluoresce over frequency ranges that are shifted with respect to each other, thereby resulting in extended tunability. Following a time-dependent analysis of a rate-equation model that describe the operation of such a laser, theoretical estimates for optimum dye concentrations and the corresponding extension of the laser tuning range have been obtained.

A study on cryopreservation of cultured rabbit periodontal ligament cells.

Cultured rabbit periodontal ligament cells were subjected to short term cryopreservation in liquid nitrogen, for a period of 84 hours and 168 hours, to study the effect of cryopreservation on coll viability and culturing ability. The vital cell count performed by Trypan Blue exclusion was 14.93 x 10(0) cells/ml in vial A and 9.11 x 10(6) cell/ml in vial B, before cryopreservation. The loss of viability was minimal--vital cell count being 14.64 x 10(6) cells/ml in vial A and 8.87 x 10(6) cells/ml in vial B after 84 hrs of cryopreservation and 14.6 x 10(6) cells/ml in vial A and 8.82 x 10(6) cells/ml in vial B after 168 hours of cryopreservation. The cryopreserved cells after thawing could grow again in cultured.

High-repetition-rate, narrow-band dye lasers with water as a solvent for dyes.

The performance of a copper vapor laser-pumped narrow-band dye laser in oscillator-amplifier configuration with water-based binary mixture solvents is described. Although oscillator efficiency in water-surfactant (sodium lauryl sulfate) solvent was comparable with that that employed pure ethanolic solvent, amplifier efficiency was found to be lower. Experiments that were carried out with vertically polarized pump beams and either horizontally or vertically polarized signal beams show that, in case of both the pump and signal having orthogonal polarization (horizontal) and same polarization (vertical), the extraction efficiency for both ethanolic and water-micelle media increased substantially from 15.7% to 18.5% and from 10% to 12.5%, respectively. However, the relative difference remained nearly the same, indicating that a slower orientational diffusion of excited dye molecules in a micellar medium is not responsible for a decrease in amplifier efficiency. Amplifier efficiency comparable with that containing ethanolic dye solutions could be obtained with a binary solvent that comprises a mixture of water and about 30% n-propanol. The performances of two efficient dyes, Rhodamine-6G and Kiton Red S, using water-based solvents were studied.