Micro-Raman spectroscopy analysis of dentin remineralization using eggshell derived nanohydroxyapatite combined with phytosphingosine

The aim of this study was to assess the remineralization efficacy of chicken eggshell-derived nano-hydroxyapatite (CEnHAp) combined with phytosphingosine (PHS) on artificially induced dentinal lesions. PHS was commercially procured whereas CEnHAp was synthesized using microwave-irradiation method and characterized using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), high-resolution scanning electron microscopy-energy-dispersive X-ray spectroscopy (HRSEM-EDX), and transmission electron microscopy (TEM). A total of 75 pre-demineralized coronal dentin specimens were randomly treated with one of the following test agents (n = 15 each): artificial saliva (AS), casein phosphopeptide-amorphous calcium phosphate (CPP-ACP), CEnHAp, PHS, and CEnHAp-PHS under pH cycling for 7, 14, and 28 days. Vickers microhardness indenter, HRSEM-EDX, and micro-Raman spectroscopy methods were used to assess the mineral changes in the treated dentin samples. Data were submitted to Kruskal-Wallis and Friedman's two-way analyses of variance (p < 0.05). HRSEM and TEM analysis depicted irregular spherical structure of the prepared CEnHAp with a particle size of 20-50 nm. The EDX analysis confirmed the presence of Ca, P, Na and Mg ions. The XRD pattern showed the characteristic crystalline peaks for hydroxyapatite and calcium carbonate that are present in the prepared CEnHAp. Dentin treated with CEnHAp-PHS revealed highest microhardness values along with complete tubular occlusion compared to other groups at all test time intervals (p < 0.05). Specimens treated with CEnHAp showed increased remineralization than those treated with CPP-ACP followed by PHS and AS groups. The intensity of mineral peaks, as observed in the EDX and micro-Raman spectra, confirmed these findings. Further, the molecular conformation of the collagen's polypeptide chains, and amide-I and CH₂ peaks attained peak intensities in dentin treated with CEnHAp-PHS and PHS whereas other groups revealed poor stability of collagen bands. Microhardness, surface topography, and micro-Raman spectroscopy analyses revealed that dentin treated with CEnHAp-PHS have an improved collagen structure and stability as well as highest mineralization and crystallinity.

Self-perception of Body Weight and Physical Activity with its Relationship to Actual Body Weight among Students in a Medical College: An Analytical Cross-sectional Study

Introduction: Obesity and sedentary life style are becoming more prevalent among the student generation. Every human being has a very good insight about the outlook. But many are not able to maintain what they perceive. During this survey, the students get a vivid picture of their real body weight and their perception of their body structure. Aim: To compare the self-perceived body weight with actual body weight among medical students and to analyse the perceptions and practice of medical student’s related to physical activity. Materials and Methods: This analytical cross-sectional study included 400 medical students. Self-perceived body image was assessed using Silhouette matching technique. Students represented the figure how they currently look (Feel) and how they actually wanted to look (Ideal). The Feel minus Ideal Discrepancy (FID) score was noted. Actual body weight and height were measured. Body Mass Index (BMI) was calculated using the Quetelet formula- weight(Kg)/height(metres)2. Perceptions and practice of physical activity were assessed using Exercise Benefits/Barrier Scale (EBBS). Comparison of perceived and actual body weight was done by Student’s Independent t-test and Pearson correlation test using Statistical Package for the Social Sciences (SPSS) version 17.0. Results: The actual BMI and perceived BMI showed strong positive correlation (r= 0.726; p=0.0001). Males had high exercise benefit scores (92) when compared with females (86) (p=0.0002). The students had high total score (benefit score plus barrier score); males had 127 and females had 124 (p=0.003) and high benefit/barrier ratio. Conclusion: Actual BMI and self-perceived BMI were well correlated indicating participant’s awareness of their body image. Male participants were more actively involved in physical activity and more concerned about maintaining their body weight. All students had higher benefit scores which is a favourable sign towards a healthy and active physical life.

Chemical Characterization of Denture Base Resin with a Novel Cycloaliphatic Monomer

AIM

The aim of this study is to identify and characterize newly formed copolymers by modifying methyl methacrylate (MMA) monomer by substituting cycloaliphatic monomer using Fourier transform infra-red (FTIR) spectroscopy.

MATERIALS AND METHODS

Heat-cure polymethyl methacrylate (HC-PMMA) experimental specimens were made by dissolving tricyclodecane dimethanol diacrylate (TCDDMDA) at 10% and 20% concentrations in commercially available MMA monomer. Specimens made without TCDDMDA served as the control. The specimen was then scrapped and mixed with dried potassium bromide (KBr) to form pellet. Each pellet was placed in a FTIR spectrometer and 10 scans were recorded with a spectral resolution of 4 cm^-1. A mean of scans was automatically processed and deduced by the system software and a final transmittance spectral graph was obtained for one specimen.

RESULTS

Three significant spectral differences exist between control and experimental groups. The first difference was the disappearance of weak peak at 1637.34 cm^-1 (alkenyl C═C stretch) in both experimental groups. The second difference was the appearance of new moderate broad peaks at 1482.25 cm^-1 and 1449.56 cm^-1 in both experimental groups which are attributed to the ring -CH₂ asymmetric bending (C-H deformation) vibrations. The third difference was the appearance of another new weak peak at 1386.57 cm^-1 in both experimental groups. This new peak confirms the formation of a new structure of copolymer.

CONCLUSION

TCDDMDA copolymerizes with MMA, thereby decreasing the uncured residual monomer in the polymerized specimens.

CLINICAL SIGNIFICANCE

Copolymerization of TCDDMDA with MMA would lead to the development of new monomeric composition for the fabrication of dentures possessing better mechanical properties and biocompatibility.

Learning style-based teaching harvests a superior comprehension of respiratory physiology

Students entering medical college generally show vast diversity in their school education. It becomes the responsibility of teachers to motivate students and meet the needs of all diversities. One such measure is teaching students in their own preferred learning style. The present study was aimed to incorporate a learning style-based teaching-learning program for medical students and to reveal its significance and utility. Learning styles of students were assessed online using the visual-auditory-kinesthetic (VAK) learning style self-assessment questionnaire. When respiratory physiology was taught, students were divided into three groups, namely, visual (n = 34), auditory (n = 44), and kinesthetic (n = 28), based on their learning style. A fourth group (the traditional group; n = 40) was formed by choosing students randomly from the above three groups. Visual, auditory, and kinesthetic groups were taught following the appropriate teaching-learning strategies. The traditional group was taught via the routine didactic lecture method. The effectiveness of this intervention was evaluated by a pretest and two posttests, posttest 1 immediately after the intervention and posttest 2 after a month. In posttest 1, one-way ANOVA showed a significant statistical difference (P=0.005). Post hoc analysis showed significance between the kinesthetic group and traditional group (P=0.002). One-way ANOVA showed a significant difference in posttest 2 scores (P < 0.0001). Post hoc analysis showed significance between the three learning style-based groups compared with the traditional group [visual vs. traditional groups (p=0.002), auditory vs. traditional groups (p=0.03), and Kinesthetic vs. traditional groups (p=0.001)]. This study emphasizes that teaching methods tailored to students' style of learning definitely improve their understanding, performance, and retrieval of the subject.

Paget's sarcoma: limb salvage by custom mega prosthesis: four case reports

Of 4 Paget's sarcoma patients (age range, 55-68 years) underwent limb salvage surgery by custom mega prosthesis, 3 had lesions in the upper extremity and one in the proximal femur. Three of the patients were at stage IIB of the disease, according to Enneking's system of staging musculoskeletal tumours. All 4 patients underwent wide resection with a mean length of 152.5 mm. The defects were reconstructed with custom-made prostheses: proximal humeral prostheses in 2 of the patients, total elbow prosthesis in one, and total hip prosthesis in one. During a mean postoperative follow-up period of 40 months, one died of disseminated disease 14 months after surgery; one remained disease-free; 2 had local recurrence and required amputation, of whom one died of disseminated disease one year after amputation, the other had no further evidence of the disease. We report the functional outcomes of the 2 patients who were alive at the latest follow-up. The 2-year patient survival rate was 50%.

Limb salvage in aggressive and malignant tumours of the fibula

We treated 25 patients with aggressive and malignant fibular tumours between April 1989 and May 2001. There were 11 osteosarcomas, seven Ewing's sarcoma and five chondrosarcomas. The tumours predominantly involved the upper one third; 16 were of Stage IIB. Neo-adjuvant and adjuvant chemotherapy were given to all patients with osteosarcoma and Ewing's sarcoma. In 20 patients, surgical margins were wide and in three radical. Mean follow-up was 71 (26-168) months. Local recurrences were met with in three patients requiring amputation. Three patients died of disease and one was lost to follow-up. Functional outcome was excellent in 12 patients and good in seven. The 5- and 10-year survival rates of patient and limb are reported based on Kaplan-Meier survival analysis.

Custom megaprosthetic replacement for proximal tibial tumours

We analysed 133 patients treated with resection and endoprosthetic proximal tibial replacement from 1988 to 2000. Mean age was 22.3 years and osteosarcoma was the most common tumour. Average follow-up was 59.4 months. An excellent functional result was achieved in 63 patients and a good result in 36. The number of patients who had no evidence of disease was 102. Twenty-four patients died due to disease. Infection was the most common complication, followed by periprosthetic fracture and aseptic loosening. The 5-year limb survival rate was 85.5%.

Proximal femoral reconstruction with custom mega prosthesis

Seventy-seven patients with proximal femoral tumours underwent limb salvage surgery with custom mega prostheses between July 1989 and January 2002. We describe 44 cases with a mean follow-up of 57.8 months. Forty-one patients presented with malignant neoplasms of which 11 were malignant giant cell tumours, eight were chondrosarcoma and five were metastases. Wide margins were achieved for all malignant tumours, and marginal resection was done for all benign and metastatic lesions. Six patients died of disease and two were lost to follow-up. Mechanical complications were observed in six cases, fracture being the most common. Oncological complications occurred in five patients. Functional activity was satisfactory in 79% of patients.