Prediction of colorectal cancer risk among adults in a lower middle-income country.

BACKGROUND: Globally, colorectal cancer (CRC) is ranked as the third most common cancer in men and the second in women. Use of a simple, validated risk prediction tool will offer a low-cost mechanism to identify the high-risk individuals for CRC. This will increase efficient use of limited resources and early identification of patients. The aim of our study was to develop and validate a risk prediction model for developing CRC for Sri Lankan adults. METHODS: The risk predictors were based on the risk factors identified through a logistic regression model along with expert opinion. A case control design utilizing 65 CRC new cases and 65 hospital controls aged 30 years or more was used to assess the criterion validity and reliability of the model. The information was obtained using an interviewer administered questionnaire based on the risk prediction model. RESULTS: The developed model consisted of eight predictors with an area under the curve (AUC) of 0.849 (95% CI: 0.8 to 0.9, P<0.001). It has a sensitivity of 76.9%, specificity of 83.1%, positive predictive value (PPV) of 82.0%, negative predictive value (NPV) of 79.3%. Positive and negative likelihood ratios are 4.6 and 0.3. Test re-test reliability revealed a Kappa coefficient of 0.88. CONCLUSIONS: The model developed to predict the risk of CRC among adults aged 30 years and above was proven to be valid and reliable and it is an effective tool to be used as the first step to identify the high-risk population who should be referred for colonoscopy examination.

Household Expenditure on Tobacco Consumption in a Poverty-Stricken Rural District in Sri Lanka.

Tobacco is a determinant of poverty and a barrier for development. Monaragala, a rural, agricultural district, reports the highest poverty-related indicators in southern Sri Lanka. A cross-sectional study was used to describe the household expenditure on tobacco and its association with food- and education-related expenditures at household level. This study used a 4-stage cluster sampling method to recruit a representative sample of 1160 households. Response rate was 98.6%. Median monthly household income was LKR 20 000 (interquartile range [IQR] = LKR 12 000-30 000). The median monthly expenditure on tobacco was LKR 1000 (IQR = LKR 400-2000) with the highest spending tertile reporting a median of LKR 2700 (IQR = LKR 2000-3600).The proportionate expenditure from the monthly income ranged from 0.0% to 50% with a median of 5.0% (IQR = 2.0-10.0) and a mean of 7.4% (7.6). The poorest reported the highest mean proportionate expenditure (9.8%, SD = 10) from the household income. Household expenditure on tobacco negatively associated with expenditure on education.

Accuracy and evaluation of a new regression equation in predicting the width of unerupted permanent canines and premolar teeth.

AIM: To assess the applicability of two regression equations based on mixed dentition analysis and to propose and evaluate a new regression equation using the mandibular incisors and first permanent molars as predictors in calculating the size of unerupted permanent canines and premolar teeth in school children. METHODS: Dental study casts of 100 children (50 males and 50 females) aged 11-14 years from schools situated in Moradabad, Uttar Pradesh, India were used. The analysis of Tanaka Johnston, Bernabe Flores-Mir and the proposed equation were tested on the casts. RESULTS: The analysis of Tanaka Johnston and Bernabe Flores-Mir tended to overestimate the mesio-distal width of the canines and premolars. The proposed equation also overestimated but the mean difference showed a closer approximation with the actual measured values compared to the other two equations. CONCLUSION: Validating studies with a similar population must be conducted to confirm the applicability and precision of the proposed equation.

Evaluation of Different Root Canal Obturation Methods in Primary Teeth Using Cone Beam Computerized Tomography.

OBJECTIVE: To evaluate the efficiency of 3 different obturation techniques; motor driven lentulospiral, hand held lentulospiral and reamer in primary anterior teeth and presence of voids by analyzing with CBCT. STUDY DESIGN: 60 single rooted extracted primary teeth were prepared and obturated with ZOE paste. Obturation methods were divided into three groups. GROUP I- motor driven lentulo spiral, II- hand held lentulo spiral and III- reamer. Obturated samples were scanned in CBCT machine and images were analysed for the evaluation of their quality of fill comprising presence, location and size of voids. RESULTS: At all the locations, Group II had maximum number of sites with voids when compared to other two groups. However, statistically significant intergroup differences were observed only at coronal third location (p=0.001) and overall assessment (p=0.003). Number of affected sites revealed the difference between Groups I and II be significant statistically (p=0.002) while the difference between Groups I and III and between Groups II and III was not significant statistically (p>0.05). At all the locations as well as for combined assessment, Group I had minimum mean size of the void. CONCLUSION: Motor driven lentulo spiral technique demonstrated more number of optimal fills with fewer voids when compared to hand held lentulo spiral technique and reamer.

Effect of ethanol wet bonding technique on the durability of resin- dentin bond with contemporary adhesive systems.

OBJECTIVE: To evaluate the effect of ethanol wet bonding technique on the immediate and long term bond strength of simplified etch and rinse adhesive systems to dentin. STUDY DESIGN: 96 extracted human permanent molars were ground to expose the flat dentin surface. The teeth were divided into four groups (n=24) according to the adhesives used, either Tetric N Bond or Solobond M and bonding techniques i.e. water wet bonding or ethanol wet bonding (EWB). Composite cylinder was bonded to each specimen using the respective adhesive technique. Ten samples from each group were then tested immediately for shear bond strength evaluation and two samples for SEM analysis. The remaining samples (12) were tested after 6 month storage in distilled water. RESULTS: Upon immediate testing, there was no significant difference in the mean shear bond strength of the groups regardless of the bonding technique or adhesive used. The bond strength fell dramatically in the water wet bonded specimens after 6 months water storage, while the bond strength of both the adhesives was maintained when EWB technique was used. SEM observation revealed good interfacial adaptation in EWB groups even after six months. CONCLUSION: For both simplified etch and rinse adhesives used, ethanol wet bonding technique led to significant preservation of the resin dentin bond over 6 months.

Dental adhesion: mechanism, techniques and durability.

Contemporary dental adhesives show favorable immediate results in terms of bonding effectiveness. However, the durability of resin-dentin bonds is their major problem. It appears that simplification of adhesive techniques is rather detrimental to the long-term stability of resin-tooth interface. The hydrostatic pulpal pressure, the dentinal fluid flow and the increased dentinal wetness in vital dentin can affect the intimate interaction of certain dentin adhesives with dentinal tissue. Bond degradation occurs via water sorption, hydrolysis of ester linkages of methacrylate resins, and activation of endogenous dentin matrix metalloproteinases. The three-step etch-and-rinse adhesives still remain the gold standard in terms of durability. This review discusses the fundamental process of adhesion to enamel and dentin with different adhesive techniques, factors affecting the long-term bonding performance of modern adhesives and addresses the current perspectives for improving bond durability.

Comparative evaluation of shear bond strength of various esthetic restorative materials to dentin: an in vitro study.

AIM: To comparatively evaluate the shear bond strength of recent tooth-colored restorative materials to dentin. MATERIALS AND METHODS: Flat dentinal surface were prepared from 60 caries free, extracted human permanent molars and were mounted in acrylic rings. These were randomly divided into four groups - Group A to Group D, according to the restorative material used i.e. Glass ionomer cement (Fuji IX), Giomer (Beautifil), an Ormocer-based composite (Admira) and Nano Ceramic restorative material (Ceram X). These restorative materials were applied on dentinal surface of all the specimens using nylon cylinders. The mounted samples were stored in distilled water for 24 hours and thermocycled. They were then subjected to shear bond strength test using universal testing machine. Data was analyzed using a one-way analysis of variance (ANOVA) and student's 't'-test. RESULTS: Ceram X (16.63 ± 0.94 MPa) and Admira (17.31 ± 0.95 MPa) were comparable in their bond strength values, but depicted significantly higher bond strength when compared to Beautifil (12.39 ± 1.05 MPa) and Fuji IX (7.76 ± 1.07 MPa). CONCLUSION: Nano-ceramic and ormocer-based restorative materials showed better bonding potential to dentin as compared to GIC and Giomer.