جستجوی مقالات مرتبط با کلیدواژه "chi-square distribution" در نشریات گروه "پزشکی"

Cleaning is one of the most important steps in preparing surgical instruments for reuse. Thorough cleaning can ensure more effective sterilization, protect treatment teams and patients from transmissible infections, and extend the life of surgical instruments. This study was conducted to compare the manual, automated, and ultrasonic methods of cleaning surgical instruments. 

In this quasi-experimental study, three types of surgical instruments, namely curved hemostats, suction tips, and Metzenbaum scissors, (n=90) from among 20 surgical sets were randomly selected and assigned to three cleaning groups viz manual, automated, and ultrasonic. After the instruments were cleaned, surface protein and blood residue swab tests were conducted and the results were recorded on a data-registration form. Data were analyzed using SPSS version 16 and descriptive and inferential statistical methods.

According to the research results, in manually cleaned instruments group, 8 (26.7%) tested positive for blood and 10 (33.3%) tested positive for protein. Of the 30 automatically cleaned instruments, 6 (20%) tested positive for blood and 7 (23.3%) tested positive for protein and of the 30 ultrasonically cleaned instruments, 1 (3.3%) tested positive for blood and protein. The chi-square test showed a statistically significant difference between the three methods of cleaning residual blood and protein from the surgical instruments (p<0.05).

The results revealed that according to the research results, of the three cleaning methods, ultrasonic cleaning was by far the most effective in removing blood and protein residues from the surgical instruments. Hence, we suggest that ultrasonic cleaning can be routinely utilized as an efficient cleaning method in medical centers.

Temporomandibular disorder (TMD) is a multifactorial problem caused by many reasons. There is still controversy about the effect of different types of occlusal disorder on TMD. This study was designed to determine the effects of centric and assisted and unassisted non-working interferences on TMD.

In this cross-sectional study, 100 dental students, including 64 males and 36 females with the age range of 18 to 24 years old, were examined. Subjects with a history of systemic or muscular diseases and orthodontic treatment were excluded. TMD signs and symptoms including maximum mandibular opening limitation, maximum lateral movement limitation, maximum protrusion limitation, deviation and deflection, joint pain and tenderness, joint sounds, and masticatory muscle tenderness were examined. Subjects were also examined for having centric interferences and eccentric interferences including assisted and unassisted non-working interferences. Data were analyzed using the chi-square test and independent-sample T-test.

Subjects with centric interference had a significantly higher number of clicks (P=0.02), medial pterygoid tenderness (P=0.009), and right medial pterygoid tenderness (P=0.007). We could also find a significantly higher number of clicking in subjects with assisted non-working interference (P=0.002).

The findings of the present study suggest that different types of occlusal interference, specially centric and assisted non-working interferences, can lead to TMD signs and symptoms.