The effects of Er:YAG, Nd:YAG, and Diode (940nm) Lasers irradiation on Microtensile bond strength of two steps self-etch adhesives.

BACKGROUND AND AIMS: Nowadays, studies show the effective laser irradiation role on the adhesion of bonding agents to the dentin. Therefore, the present study was set to find an appropriate protocol for the use of Nd:YAG, Er:YAG, and Diode lasers during the application of two steps self-etch adhesives in direct dental restorations in order to achieve higher microtensile strength. MATERIALS AND METHODS: A total number of 100 extracted healthy teeth were selected. After removing occlusal enamel and exposing dentin, samples randomly divided into ten groups: Group Control (C), two steps self-etch adhesives was applied in accordance with the manufacturer instructions, without using laser systems; Groups Er-YAG, laser (2940 nm, 10 Hz, 0.4w, 40 mJ) irradiated Before applying Primer (Er-BP subgroup), After applying Primer (Er-AP subgroup), After applying Bonding (Er-AB subgroup); Groups Nd-YAG, laser (1064 nm, 10 Hz, 1.2w, 40 mJ) irradiated Before applying Primer (Nd-BP subgroup), After applying Primer (Nd-AP subgroup), After applying Bonding (Nd-AB subgroup); Groups Diode, laser (940 nm, 10 Hz, 0.7w, 70 mJ) irradiated Before applying Primer (D-BP subgroup), After applying Primer (D-AP subgroup), After applying Bonding (D-AB subgroup). After intervention and composite build up, the samples were stored 24 hours in 37°C distilled water. The microtensile strength was measured using the universal testing machine. The data were analyzed by one-way ANOVA test and post hoc Tukey test. (p < 0.05). RESULTS: The Means and standard deviations of the groups were as follow: C = 30.09 ± 4.21, Er-BP = 18.83 ± 4.21, Er-AP = 14.43 ± 3.12, Er-AB = 19.67 ± 4.96, Nd-BP = 20.35 ± 5.55, Nd-AP = 39.85 ± 4.13, Nd-AB = 18.16 ± 3.36, D-BP = 26.74 ± 5.05, D-AP = 28.11 ± 5.12, D-AB = 37.28 ± 5.61. The mean microtensile strength achieved in groups: Nd-AP and D-AB were significantly higher than control group (p < 0.05). Groups D-BP and D-AP had no significant difference in comparison with control group while the remaining groups had significantly lower values (P < 0.05). CONCLUSIONS: Nd:YAG laser irradiation after applying the primer, and diode laser irradiation after applying the bonding agent, both can improve the microtensile bond strength in two steps self-etch adhesive systems significantly.

Total antioxidant capacity of saliva and dental caries.

OBJECTIVE: Dental caries is one of the most common infectious diseases worldwide. Saliva has many functions in the oral cavity and is the first line defense against dental caries. Oxidative stress can affect initiation and progression of many inflammatory and infectious diseases such as dental caries. Thus the aim of this study was to evaluate the relationship between total antioxidant capacity (TAC) of saliva and dental caries. STUDY DESIGN: 100 healthy high school students (50 female and 50 male) with age range of 15 -17 years were randomly selected, divided to four groups. Unstimulated whole saliva specimens were collected at the morning. TAC of saliva was evaluated by spectrophotometric assay. Statistical comparisons were performed using Student's t-test, by SPSS 13. RESULTS: The level of TAC was significantly higher in the saliva of caries active group relative to the caries free subjects. Statistical analysis for male and female groups showed a statistically significant reduction of TAC level in female group. CONCLUSION: TAC was higher in caries active group. Thus this result showed that total antioxidant capacity may influence in dental caries and activity can be measured by salivary factors and this may be helpful in preventive dentistry.

A clinicopathological survey of Basal cell carcinoma in an Iranian population.

STATEMENT OF PROBLEM: Basal cell carcinoma (BCC), the most common skin cancer, is a locally invasive malignant epidermal tumor with ulceration and destruction of underlying structures. PURPOSE: The purpose of this study was clinicopathological evaluation of BCC in the state and the private pathology centers in Hamadan province during 1990-2010. MATERIALS AND METHOD: In this retrospective study all histopathologically proven cases of BCC were reviewed and the related information including age, gender, place of residency and number of tumors for the patients alongside with the site of occurrence, size, histopathological and clinical type of the lesions were collected and then statistically analyzed, using SPSS software. RESULTS: A total of 804 incidents of BCC were diagnosed in 746 patients (296 females and 450 males) with the most affected site being in the head-face (84.8%), neck (2.6%), trunk (1.6%) and limbs (0.9 %) and 10.1% cases with unknown site. The mean age for the patients was 61.77±13.75 years (63.07± 13.44 for males, 59.81 ± 14.01 for females) and the highest frequency (27.2%) occurred among 60-69 years age group. Nodular type was the most common clinical and histopathological BCC lesions studied whereas the mean size of the lesions was 15.67 ± 11.06 mm with more frequency rate in urban than rural regions. CONCLUSION: This study focuses on the survey of BCC in Hamadan province but regarding to insufficiency of the data collected by state and provincial pathology centers about the BCC cases reported; it is highly recommended to apply comprehensive questionnaire, which are designated by skillful professionals who are familiar with the lesion nationally.

Classification of Death Rate due to Women's Cancers in Different Countries.

BACKGROUND: The two most frequently diagnosed cancers among women worldwide are breast and cervical cancers. The objective of the present study was to classify the different countries based on the death rates from sex specific cancers. METHODS: In this cross-sectional study, we used dataset regarding death rate from breast, cervical, uterine, and ovarian cancers in 190 countries worldwide reported by World Health Organization. Normal mixture models were fitted with different numbers of components to these data. The model's parameters estimated using the EM algorithm. Then, appropriate number of components was determined and was selected the best-fit model using the BIC criteria. Next, model-based clustering was used to allocate the world countries into different clusters based on the distribution of women's cancers. The MIXMOD program using MATLAB software was used for data analysis. RESULTS: The best model selected with four components. Then, countries were allocated into four clusters including 43 (23%) in the first cluster, 28 (14%) in the second cluster, 75 (39%) in the third cluster, and 44 (24%) in the fourth cluster. Most countries in South America were to the first cluster. In addition, most countries in Africa, Central, and Southeast Asia were located to the third cluster. Furthermore, the fourth cluster consisted of Pacific continent, North America and European countries. CONCLUSION: Considering the benefits of clustering based on normal mixture models, it seems that can be applied this method in wide variety of medical and public heath contexts.

Evaluation of Injuries among a Manufacturing Industry Staff in Iran.

BACKGROUND: Occupational injury is related to personal characteristics. This phenomenon is a controversial issue. This paper presents the relationships of certain occupational and individual characteristics with frequency of occupational injuries. METHODS: A standardized injury questionnaire was completed for 199 employees in a big Iranian industrial company (MAPNA Group) by the researcher in the presence of the subjects. The data were analyzed using zero-inflated Poisson regression with random effects. RESULTS: We demonstrated a significant relation between the marital status (P< 0.001) and score of injures (P < 0.001) with number of injuries by employees. Technicians and supervisors have high chance of "not to be injured at all" relative to workers (P< 0.05). Technicians and supervisors have less number of injuring than workers have (P< 0.05). In addition, increasing assessment score decreases the number of injuring of employees (P< 0.001). CONCLUSION: Due to being aware of the risks and remedial measures, married employees and workers should be assisted by occupational specialists.