Caspian Journal of Dental Research

Introduction: When using sliding mechanics for space closure during orthodontic treatment, friction occurs at the bracket-wire interface. The aim of this study was to evaluate the frictional resistance between monocrystalline (ICE) brackets and Stainless Steel, Beta TMA and NiTi wires.

Methods: In this experimental study, we used 5 different types of orthodontic wires. Brackets and wires were divided in to 5 groups: 1-(monocrystalline+stainless steel 18) 2–(monocrystalline+stainless steel 19×25) 3-(monocrystalline+Beta-TMA) 4–(monocrystalline+Beta TMA 19×25) 5-(monocrystalline+NiTi 18). Instron Universal Testing Machine was used to investigate the static frictional resistance. The angulation between bracket and wire was 0 and the wires were pulled through the slots at a speed of 10 mm/min. Tests were performed 10 times for each group in artificial saliva. The average of 10 forces recorded was considered as static friction. One-way ANOVA and SPSS Version 18 and LSD post hoc test were used to evaluate the results of the study.

Results: The mean static frictional force for each group was: group1: 0.82 ± 0.14, group 2: 1.09 ± 0.30, group 3: 0.87 ± 0.53, group 4: 1.9 ± 1.16, group 5: 1.42 ± 0.30. There was a significant difference when comparing the two groups of similar wires in terms of shape (round or rectangular cross-section) as when comparing Beta TMA 18 and 19×25 arch wires with each other, the obtained p-value was 0.023, while the obtained p-value for the comparison of stainles steel arch wires was 0.034 .

Conclusions: The result of this study shows that Stainless Steel 18 wires generate the least amount of friction and round wires produce less friction than the rectangular wires. Beta TMA wires generate the highest amount of friction.

Introduction: Obesity as a pervasive phenomenon in recent years has the risky consequences on public and oral health and endangers the teeth especially periodontal tissues. This aim of this study was to assess the relationship of oral health (teeth and periodontal tissue) with obesity and anthropometric measures such as waist circumference (WC) and body mass index (BMI).

Materials &Methods: This cross sectional study was conducted on 180 subjects in 3 groups of normal weight, over-weight and obese. Periodontal pocket depth (PPD), bleeding on probing (BOP) and Community Periodontal Index (CPI) were recorded.  Multivariate logistic regression was also applied after adjusting for the confounding factors.

Results: Of 180 subjects, 54, 68 and 58 cases were normal, overweight and obese. 75 and 105 participants were male and female, respectively. Generally, a pocket depth was increased 1.394 times with one unit increase of BMI (OR: 1.394, 95% CI: 0.936-2.077). Dental caries index enhanced to 1.036 with one unit increase of waist circumference (WC) (OR: 1.036, 95% CI: 1.001-1.071). One centimeter rise of WC increased CPI up to 0.625 times (OR: 1.122, 95% CI: 0.053-0.078).

Conclusion: Obesity even in the absence of underlying systemic diseases can cause the potential risk in oral health.