Prevalence and Determinants of Obesity and Overweight Among Children and Adolescents in the Middle East and North African Countries: An Updated Systematic Review.

In recent years, the countries of the Middle East and North Africa (MENA) region have experienced alarming increases in the prevalence of childhood overweight and obesity. This updated systematic review sought to measure the prevalence and determinants of obesity and overweight among children and adolescents in MENA countries. A literature search for relevant observational studies published in English was conducted using PubMed, Web of Science, Google Scholar, and Saudi Digital Library. The risk of bias was evaluated using the Newcastle-Ottawa Scale. Twenty-one published articles during the past five years were included in the systematic review. Varied approaches were used to diagnose childhood overweight and obesity, including the International Obesity Taskforce (IOTF), Centre for Disease Control (CDC), World Health Organization (WHO), and Saudi Growth Pattern Curves. We found that the combined prevalence of childhood overweight and obesity in the Middle East is up to 49.4%, depending on the methods applied in their studies. Risk factors identified were age, male gender, lack of sufficient physical activity, consumption of fried food, perceived stress level, number of family members, family size, mother's occupation, education level, family history of obesity, high energy consumption from carbohydrates, ≥2 hours spent on watching television on weekend days with overweight, and always eating breakfast while watching television with obesity. The results of this review indicate that the issue of childhood and adolescent overweight and obesity in the Middle East is substantial and concerning. Most of the risk factors identified are modifiable and, if given appropriate attention, could significantly reduce the burden of associated chronic complications.

Angle of convergence of posterior crown preparations made by predoctoral dental students.

The aim of this study was to determine angle of convergence (AC) of posterior crown preparations made by predoctoral dental students at the University of Toronto. Ninety-one dies of students' crown preparations were digitally scanned with an in-Eos-Blue scanner (Sirona). Created images were virtually sliced at three similar locations of mesiodistal and buccolingual planes. Virtual protractor was used to determine AC of each section. Means and SDs were calculated, and data were statistically analyzed with ANOVA and student's t-test for operator's gender, experience, and tooth type. There were no significant differences among the groups except for AC of preparations grouped by tooth type (p<0.0001). The greatest mean mesiodistal AC was 26.4° found with mandibular molars, while the smallest was 16° found with maxillary premolars. ANOVA revealed significant difference in mean mesiodistal AC among groups (p<0.01). Also, greatest mean buccolingual AC was 25° found with mandibular molars, while the smallest was 20.8° found with maxillary premolars. ANOVA did not reveal significant difference in mean buccolingual AC among groups (p>0.05). Overall mean AC values were greater than ideal range of 2-5°; however, they were within ranges published for dentists/prosthodontists. Gender and experience had no significant effect on AC, but tooth type significantly affected AC.

Effect of precuring warming on mechanical properties of restorative composites.

To investigate the effect of prepolymerization warming on composites' mechanical properties, three composites were evaluated: Clearfil Majesty (CM) (Kuraray), Z-100 (3M/ESPE), and Light-Core (LC) (Bisco). Specimens were prepared from each composite at room temperature as control and 2 higher temperatures (37°C and 54°C) to test surface hardness (SH), compressive strength (CS), and diametral tensile strength (DTS). Data were statistically analyzed using ANOVA and Fisher's LSD tests. Results revealed that prewarming CM and Z100 specimens significantly improved their SH mean values (P < 0.05). Prewarming also improved mean CS values of Z100 specimens (P < 0.05). Furthermore, DTS mean value of CM prepared at 52° was significantly higher than that of room temperature specimens (P < 0.05). KHN, CS, and DTS mean values varied significantly among the three composites. In conclusion, Prewarming significantly enhanced surface hardness of 2 composites. Prewarming also improved bulk properties of the composites; however, this improvement was significant in only some of the tested materials.