Background. It is crucial to maintain periodontal health in patients undergoing orthodontic treatment. Biotype is a critical factor to be considered in this regard. This systematic review investigated the scientific evidence on the relationship between gingival biotype and marginal periodontal alterations induced by orthodontic interventions. Methods. An electronic search was conducted for pertinent studies in three databases: PubMed, Scopus, and Cochrane up to August 1, 2019 based on a detailed protocol according to the PRISMA statement. The authors also completed a hand search in six dental journals and the bibliographic lists of the relevant studies. Results. Of 1512 citations retrieved through the electronic search, 602 were duplicate entries. By evaluating titles, abstracts, and full texts, eight articles conformed to the inclusion criteria; however, no relevant studies were found through hand searching. The evidence suggested that recession was inversely related with the thickness of the facial margin. These findings were more evident in proclined teeth and patients using fixed appliances. Conclusion. The existing evidence suggests that orthodontic therapy might result in mild detrimental effects on the periodontium, especially in patients with thin biotype. However, due to the limited investigations and their inconsistent methodology, further well-designed prospective studies are necessary.

Objective: This study aimed to evaluate the accuracy of linear measurements made on CBCT (New Tom VGi) scans with different image magnifications. Methods: Forty-two titanium pins were inserted into seven dry sheep mandibles. Lengths of the pins were measured using a digital caliper with 0.01 mm readability, and the mandibles were radiographed using a CBCT unit. After reconstruction of CBCT images, three experienced radiologists measured the length and diameter of titanium pins at100%, 200% and 400% magnifications. Accuracy of measurements was analyzed using descriptive statistics and one-way analysis of variance (ANOVA) P<0.05 was considered statistically significant. Inter observer reliability was calculated using the intra class correlation coefficient (ICC) test. Results: The mean differences of linear measurements from the actual lengths of pins were 0.1960 mm, 0.2143 mm and 0.2047 mm at 100%, 200% and 400% magnifications, respectively (P>0.05). The mean differences of linear measurements from the actual diameters of pins were 0.2206 mm, 0.2063 mm and 0.1984 mm at 100%, 200% and 400% magnifications, respectively (P>0.05). Inter observer reliability of pin length measurements was estimated to be0.285, 0.707 and 0.479 at 100%, 200% and 400%magnifications, respectively. Inter observer reliability of pin diameter measurements was 0 .078, 0.469 and 0.587 at 100%, 200% and 400%magnifications, respectively. Conclusion: Based on the results, image magnification does not affect the accuracy of linear measurements made on CBCT scans. Inter observer reliability of pin length measurements was good at 200% magnification, while it was below the acceptable range at other magnifications. For measurement of pin diameters, this index was below the acceptable range at all magnifications.

Objective: To systematically review the randomized clinical trials (RCTs) on the effect of Platelet Rich Fibrin (PRF) concentrate on the tissue regeneration of intra-oral defects. Methods: An electronic search was performed in PubMed/Medline and Cochrane Library using relevant keywords until June 2018. RCTs which used PRF concentrate for treatment of intrabony defects, sinus augmentation, furcation involvement, endo-periodontal lesions, gingival recession, and ridge preservation were included in the present review. Results: In total, 79 studies that were used PRF either solely or mixed in human trials were included and divided based on the defect type. Most of the studies used PRF to treat intra-bony defects showed that it would improve treatment outcomes. In case of furcation involvement, the application of L-PRF in addition to open flap debridement improved the bone regeneration in grade II mandibular furcation involvement. In case of ridge preservation and sinus floor augmentation, the results were controversial. Conclusions: The result of the current systematic review implied that the treatment outcome of PRF application for periodontal and soft tissue repair depends on the treatment strategies and type of the defect. It was shown to PRF application is a practical approach to accelerate and enhance new bone formation in human studies in intrabony defects and furcation involvements.  However, further clinical trials for evaluation of other types of intra-oral defects are required.

Objective This study aimed to evaluate the accuracy of linear measurements made on cone beam computed tomography (CBCT) (New Tom VGi) scans with different image magnifications. Methods Forty-two titanium pins were inserted into seven dry sheep mandibles. Lengths of the pins were measured using a digital caliper with 0.01 mm readability, and the mandibles were radiographed using a CBCT unit. After reconstruction of CBCT images, three experienced radiologists measured the length and diameter of titanium pins at 100%, 200% and 400% magnifications. Accuracy of measurements was analyzed using descriptive statistics and one-way analysis of variance. P < 0.05 was considered statistically significant. Interobserver reliability was calculated using the intraclass correlation coefficient test. Results The mean differences of linear measurements from the actual lengths of pins were 0.1960, 0.2143 and 0.2047 mm at 100%, 200% and 400% magnifications, respectively (P > 0.05). The mean differences of linear measurements from the actual diameters of pins were 0.2206, 0.2063 and 0.1984 mm at 100%, 200% and 400% magnifications, respectively (P > 0.05). Interobserver reliability of pin length measurements was estimated to be 0.285, 0.707 and 0.479 at 100%, 200% and 400% magnifications, respectively. Interobserver reliability of pin diameter measurements was 0.078, 0.469 and 0.587 at 100%, 200% and 400% magnifications, respectively. Conclusion Based on the results, image magnification does not affect the accuracy of linear measurements made on CBCT scans. Interobserver reliability of pin length measurements was good at 200% magnification, while it was below the acceptable range at other magnifications. For measurement of pin diameters, this index was below the acceptable range at all magnifications.

Objectives: This study assessed the prevalence of dental trauma among the 5-6, 12 and 15-year-old Iranian children. Age, sex and place of residence of children with dental trauma and the correlation between parental level of education and prevalence of dental trauma were also evaluated. Methods: In this descriptive, cross-sectional study, we used the 2012-national survey data on oral health, which included a sample of Iranian individuals recruited from all provinces of Iran. A cluster random sample of 26,000 children in 3 age groups were included in this study. SPSS software was used for statistical analysis after quality control and data clean up. Results: The overall prevalence of dental trauma was 4.1% for the total sample. This value was 5.4% in boys and 3.1% in girls. The most common age of occurrence was 15 years (6%) followed by 12 years (4.9%) and 5-6 years (1.5%) of age. The highest percentage of dental trauma in 12 and 15-year-old children was noted in “Kohkiloye and Boyerahmad” Province. Higher level of parental education was associated with lower frequency of trauma in all age groups. The prevalence of dental trauma was lower among those residing in rural compared with urban areas. Conclusion: This study demonstrated relatively high prevalence of dental traumatic injuries among 5-15 year-old Iranian children (4.1%). Based on the reported associations, more effort is necessary to educate all parents and children on trauma prevention with priority in urban areas.