Darshan Devang Divakar

The Effect of Hydrofluoric Acid Etching Duration on the Surface Micromorphology, Roughness, and Wettability of Dental Ceramics.

The current laboratory study is evaluating the effect of hydrofluoric acid etching duration on the surface characteristics of five silica-based glass ceramics. Changes in the pore pattern, crystal structure, roughness, and wettability were compared and evaluated. Seventy-five rectangularly shaped specimens were cut from each material (IPS e-max™, Dentsply Celtra™, Vita Suprinity™, Vita mark II™, and Vita Suprinity FC™); the sectioned samples were finished, polished, and ultrasonically cleaned. Specimens were randomly assigned into study groups: control (no etching) and four experimental groups (20, 40, 80 and 160 s of etching). The etched surfaces’ microstructure including crystal structure, pore pattern, pore depth, and pore width was studied under a scanning electron microscope, and the surface roughness and wettability were analyzed using a non-contact surface profilometer and a contact angle measuring device, respectively. The results were statistically analyzed using one-way analysis of variance (ANOVA) and the post hoc Tukey’s test. The results showed a significant change in the pore number, pore pattern, crystal structure, surface roughness, and wettability with increased etching duration. Etching for a short time resulted in small pores, and etching for longer times resulted in wider, irregular grooves. A significant increase in the surface roughness and wettability was observed with an increase in the etching duration. The findings also suggested a strong association between the surface roughness and wettability.

Preliminary fabrication and characterization of electron beam melted Ti–6Al–4V customized dental implant

The current study was aimed to fabricate customized root form dental implant using additive manufacturing technique for the replacement of missing teeth. The root form dental implant was designed using Geomagic™ and Magics™, the designed implant was directly manufactured by layering technique using ARCAM A2™ electron beam melting system by employing medical grade Ti–6Al–4V alloy powder. Furthermore, the fabricated implant was characterized in terms of certain clinically important parameters such as surface microstructure, surface topography, chemical purity and internal porosity. Results confirmed that, fabrication of customized dental implants using additive rapid manufacturing technology offers an attractive method to produce extremely pure form of customized titanium dental implants, the rough and porous surface texture obtained is expected to provide better initial implant stabilization and superior osseointegration.

Prevalence of oral mucosal lesions among fishermen of Kutch coast, Gujarat, India

BACKGROUND The aim of the study was to assess the prevalence of oral mucosal lesions among fishermen population in the coastal region of Kutch, Gujarat, India. MATERIALS AND METHODS A descriptive cross-sectional survey was conducted to assess the prevalence of oral mucosal lesions among the 979 fishermen of Kutch District, Gujarat, India. The proforma included information on demographic details, habits (tobacco and alcohol), oral hygiene practices and presence and location of oral mucosal lesions according to World Health Organisation, 2013. Chi-square test was used for comparisons. Confidence level and p-value were set at 95% and 5%, respectively. RESULTS The majority of study population consumed tobacco and alcohol (88.1%) in some or the other form and used chewsticks (42.9%) for cleaning their teeth. Amongst all, 30.03% of the study subjects suffered from oral mucosal lesions. Leukoplakia (13.8%) was found to be the most prevalent lesion. The most affected sites were lips and vermillion border. The prevalence of oral mucosal lesions was found to be significantly associated with age, gender, oral hygiene practices and adverse habits. CONCLUSIONS Oral mucosal lesions were prevalent among 30.03% of the study population. More detailed studies probing this issue should be conducted and efforts should be directed towards primordial prevention of the conditions.

Microbiome of dental implants and its clinical aspect

Although dental implants are most common prosthetic treatment used to replace missing tooth, it gained considerable importance over a decade owing to the availability of advanced imagery techniques that can help in achieving a greater success rate and much better osseointegration. However, the chances that the implanted tooth can be rejected due to inflammation caused by oral microflora still persist. This review gives the viewers an overall idea of the dental implants, role of advanced imaging in implantation and instances of peri-implantitis that occur after implantation process. This review also entails the latest research on the different treatment modalities against peri-implantitis documented in peer-review journals.

Chitosanase purified from bacterial isolate Bacillus licheniformis of ruined vegetables displays broad spectrum biofilm inhibition

A number of bacterial species produces chitosanases which has variety of applications because of its high biodegradability, non-toxicity and antimicrobial assets. In the present study chitosanase is purified from new bacterial species Bacillus licheniformis from spoiled vegetable. This novel strain of Bacillus licheniformis isolated from spoilt cucumber and pepper samples has the ability to produce the chitosanase enzyme when grown on chitosan substrate. Study also examined its antibiofilm properties against diverse bacterial species with biofilm forming ability. The purified chitosanase inhibited the biofilm formation ability for all Gram-negative and Gram-positive biofilm-forming bacteria [biofilm producers] tested in this study in congo red agar and microtiter plates methods. Highly antibiofilm activity of chitosanase was recorded against Pseudomonas aeruginosa followed by Klebsiella pneumoniae with reduction of biofilm formation upto 22 and 29%, respectively compared with [100] % of control. Biofilm formation has multiple role including ability to enhance resistance and self-protection from external stress. This chitosanase has promising benefit as antibiofilm agent against biofilm forming pathogenic bacteria and has promising application as alternative antibiofilm agents to combat the growing number of multidrug resistant pathogen-associated infections, especially in situation where biofilms are involved.

Effectiveness of health education and behavioral intervention for tobacco de-addiction among degree students: A clinical trial

Background: Objectives of the study were to assess the prevalence of tobacco use among the degree students of Oxford institutions in Bangalore city, offer a tobacco cessation intervention for tobacco users among the degree students, and assess the effectiveness of intervention by comparing with the control group. Materials and Methods: A randomized control trial was conducted to assess the prevalence of tobacco use and the effectiveness of tobacco cessation behavioral intervention offered to degree students of Oxford institutions in Bangalore city. Then were randomly selected and divided into 55 students in the study group (group A) and 60 students in the control group (group B). Results: The effect of intervention of tobacco cessation in group A showed an increase of 29.1% students who stopped using tobacco completely after intervention compared to 15% in group B, and the highest reduction of 21.8% change was noticed in the students using one to five tobacco products per day and the least reduction in percentage (1.8%) change was noticed in the students using one tobacco product per day. Conclusion: Findings from the present study suggest that the intervention has suggestive significance on tobacco intervention.

Outcome of Palliative and Radical Radiotherapy in Patients with Oral Squamous Cell Carcinoma - a Retrospective Study

BACKGROUND The treatment selection for the oral squamous cell carcinoma remains controversial. Radiation therapy or surgical excision of the lesion can be applied as the sole treatment or it can be used in combination with other treatment modalities. Radiotherapy is considered to be the safest of all the treatment modalities and can be used in several situations for oral and oropharyngeal cancers. The aim of this study was to evaluate the survival outcome differences in patients treated with radical and palliative radiotherapy as the primary treatment modality. MATERIALS AND METHODS The study included a total of 47 patients with oral cancer reporting to our hospital between years 2009 to 2010. The age group for the selected patients was more than 65 years, treated with radical and palliative radiotherapy with no prior surgical interventions. Patients were evaluated till Dec 2013 for overall survival time. RESULTS Twenty nine patients were treated with radical radiotherapy as main stay of treatment, out of which 21 died during the follow up time with median survival of 352 ± 281.7 days with 8 patients alive. All the 16 patients were dead who received palliative radiotherapy with a median survival time of 112 ± 144.0 days. CONCLUSIONS This retrospective study showed improved overall survival time, loco regional control rates and reduced morbidity in patients treated with radical radiotherapy when compared to patients treated with palliative radiotherapy.

End Stage Palliative Care of Head and Neck Cancer: a Case Study

BACKGROUND Locally advanced head and neck cancer is generally incurable and has a short survival rate. This study aimed to evaluate symptom relief, disease response, and acute toxicity after palliative hypo-fractionated radiotherapy and long-term survival in affected patients. MATERIALS AND METHODS Between January 2011 to December 2011, 80 patients who were histopathologically diagnosed as having stage III or stage IV head and neck squamous cell carcinoma based on Eastern Cooperative Oncology Group (ECOG) performance status 1-3, were offered palliative radiotherapy (20 Gy/5Fr/5 Days). Later these patients were evaluated on 30th day after completion of treatment for disease response based on World Health Organisation (WHO) criteria and palliation of symptoms using symptomatic response grading and acute toxicities by the Radiation Therapy Oncology Group (RTOG). Many patients were given post radiation therapy (RT) palliative chemotherapy for appropriate palliative care and a few patients were selected for further curative RT. The overall survival was also evaluated among this group of patients with last follow up date of 1st May, 2014. RESULTS The most common presenting complaint was pain followed by dysphagia. Most patients (60-70%) had appreciable relief in their presenting symptoms. A good response was observed in the majority following palliative RT; a few patients had progressive disease and some had stable and regressed disease. None of the patients experienced radiation toxicity that required hospital admission. Almost all showed grade one and two acute skin and mucosal toxicity one month after completion of treatment. The mean survival days for patients given only hypofractionated palliative RT was 307 days, those with post palliative RT and palliative chemotherapy was 390 days and patients who went on to receive further palliative RT and curative RT dose had significantly overall survival of 582 days. CONCLUSIONS Advanced head and neck cancer should be identified for suitable palliative hypofractionated radiotherapy to achieve acceptable symptom relief in a great proportion of patients and should be followed by palliative chemotherapy or curative RT in suitable cases for long-term symptom-free survival.

The Effect of Lithium Disilicate Ceramic Surface Neutralization on Wettability of Silane Coupling Agents and Adhesive Resin Cements

This in vitro study was aimed to evaluate the possible changes in wettability of an etched glass ceramic surface to silane primers, adhesive resin and resin cement when the surface had been neutralized by a special neutralizing agent after etching. Rectangular shaped specimens were cut from the CAD blocks of an e-max lithium disilicate glass ceramic, cut specimens were sequentially polished and ultrasonically cleaned. All the specimens were etched for 20 s with 5% hydrofluoric acid and ultrasonically cleaned. Specimens were randomly assigned to one control group (without neutralization) and one treatment group (with neutralization) having 20 specimens each. The specimens of each group were further divided into two subgroups having 10 specimens each and tested to determine the effect of neutralizing agent on wettability of experimental and commercial silanes. Each subgroup specimen was tested for wettability to adhesive resin and commercial resin cement. Data were analyzed using two-way ANOVA. Neutralizing the ceramic surface did not show a significant effect on wettability to the silanes and the resin based materials, but the experimental silane showed better wettability than the commercial silane. The adhesive resin had statistically significant lower contact angle (high wettability) values than the commercial resin cement. The results of the current study suggested that the neutralizing agent did not have an impact on the wettability of the etched ceramic. However, there were differences in wetting properties of the silane primers, and adhesive resin versus resin composite luting cements.

Two-step vs. one-step conditioning systems and adhesive interface of glass ceramic surface and resin systems

Abstract The effect of two-step and one-step ceramic surface conditioning/priming, and subjecting to exposure with boiling water on adhesion strength of resin cements was evaluated. Rectangular shaped specimens were cut from CAD blocks of E-max (Ivoclar Vivadent) and Mark II (VITA Zahnfabrik) and randomly assigned to two main study groups. Group one specimens’ surfaces were conditioned using the two-step conditioning/priming procedure and group two specimens were treated using the one-step conditioning/priming system. After treating, 3 mm thick resin cement layer was applied onto the surface using a split stainless steel mold. Each group was further divided into four subgroups (n = 10) depending on type of resin cement applied and subjecting to exposure in boiling water. Adhesion strength of all the specimens was measured using the universal material testing machine, results were tabulated and subjected to statistical analysis at a significance level of p < 0.05. Adhesive resin showed higher values of 22.05 and 18.65 MPa with E-max and Mark II respectively, and resin composites showed 18.13 and 15.13 MPa with E-max and Mark II respectively, when two-step conditioning system was employed. Majority of the adhesive resin specimens showed cohesive failure in cement. Subjecting the specimens to exposure in boiling water for 24 h not only showed adhesive failure but also significantly reduced adhesion strength of adhesive resin and resin composite. The significance of the study is that, the traditional two-step ceramic surface conditioning is more effective than the one-step conditioning and unfilled adhesive resin provides better adhesion strength.