Management of post-orthodontic white spot lesions and subsequent enamel discoloration with two microabrasion techniques

Statement of the Problem: Demineralization of enamel adjacent to orthodontic appliances frequently occurs, commonly due to insufficient oral hygiene

Purpose: The aim of this study was to compare two microabrasion techniques on improving the white spot lesions as well as subsequent enamel discoloration

Materials and Method: Sixty extracted premolar teeth without caries and hypoplasia were selected for this study. White spot lesions were artificially induced on the buccal surface of each tooth. Teeth were randomly assigned to three treatment groups, each treated with pumice powder as the control, microabrasion with 18% HCl, and microabrasion with 37% H3PO4. Subsequently, the three groups were daily immersed for five minutes in a tea-coffee solution for a period of one week. Colorimetric evaluation was done before and after formation of white spot lesions, after microabrasion, and after immersion in the colored solution; then the color differences [Delta E] were calculated. Statistical analysis was performed by multiple measurement analysis and the Tukey's test

Results: This study showed that Delta E between the stages of white spot formation and microabrasion for H3PO4 was more than other groups and for the pumice powder group it was less than the others. Furthermore, there was a significant difference between Delta E of the three study groups [p= 0.017]. Additionally, Delta E after placing the teeth in the colored solution and microabrasion was the highest for the HCl group and the lowest for the pumice powder group. There was also a significant difference between the three groups [p= 0.000]

Conclusion: Pumice powder alone had similar effects as 18% HCl on removing the white spot lesions. Nevertheless, 18% HCl makes the enamel susceptible for subsequent color staining more than the other microabrasion methods

Comparison of antibacterial effects of ZnO and CuO nanoparticles coated brackets against streptococcus mutans

Statement of the Problem: During the orthodontic treatment, microbial plaques may accumulate around the brackets and cause caries, especially in high-risk patients. Finding ways to eliminate this microbial plaque seems to be essential

Purpose: The aim of this study was to compare the antibacterial effects of nano copper oxide [CuO] and nano zinc oxide [ZnO] coated brackets against Streptococcus mutans [S.mutans] in order to decrease the risk of caries around the orthodontic brackets during the treatment

Materials and Method: Sixty brackets were coated with nanoparticles of ZnO [n=20], CuO [n=20] and CuO-ZnO [n=20]. Twelve uncoated brackets constituted the control group. The brackets were bonded to the crowns of extracted premolars, sterilized and prepared for antimicrobial tests [S.mutans ATCC35668]. The samples taken after 0, 2, 4, 6 and 24 hours were cultured on agar plates. Colonies were counted 24 hours after incubation. One-way ANOVA and Tukey tests were used for statistical Analysis

Results: In CuO and CuO-ZnO coated brackets, no colony growth was seen after two hours. Between 0-6 hours, the mean colony counts were not significantly different between the ZnO and the control group [p>0.05]. During 6-24 hours, the growth of S.mutans was significantly reduced by ZnO nanoparticles in comparison with the control group [p< 0.001]. However, these bacteria were not totally eliminated

Conclusion: CuO and ZnO-CuO nanoparticles coated brackets have better antimicrobial effect on S.mutans than ZnO coated brackets

Analysis of MTHFR gene C.677C>T and C.1298A>C polymorphisms in Iranian patients with non-syndromic cleft lip and palate

Non-syndromic cleft lip with or without cleft palate [nsCL/P] is one of the most common congenital abnormalities of the orofacial region with a multifactorial etiology. The present study aimed to investigate the association of two common polymorphisms of methylenetetrahydrofolate reductase [MTHFR] gene [c.677C>T and c.1298A>C] with the occurrence of nsCL/P in an Iranian population. Forty-five nsCL/P patients, 43 mothers of patients, and 101 unrelated controls participated in the present study. Analysis of c.677C>T and c.1298A>C polymorphisms in MTHFR gene was conducted using polymerase chain reaction and restriction enzyme digestions. There was no statistical difference in genotype and allele frequencies for c.677C>T variants between patients or their mothers and the control group. However, differences in the frequencies of alleles and genotypes of c.1298A>C polymorphism were statistically significant between patients and control group [P=0.01 for alleles and P=0.005 for genotypes]. The odds ratios [OR] for the CC versus AA homozygotes were 6.1 [95% CI 1.8-20.5] and 4.2 [95% CI 1.1-15.4], in patients and mothers, respectively. We found no association between genetic polymorphism of MTHFR c.677C>T and the risk of nsCL/P in the population studied. Yet the results suggested that c.1298A>C polymorphism of MTHFR gene may be a risk factor for the occurrence of nsCL/P in the Iranian population

Evaluation of nsomaxillary growth of adolescent boys in northeastern Iran

Anthropometry, a useful method for evaluating craniofacial soft tissues, makes the quantitative description of the face possible. It also assesses the degree of disharmony and imbalance in the growth and development of the face. The aim of this study was to examine the overall common age-related changes of nasomaxillary complex of adolescent boys in northeast Iran. Three- hundred- twelve 12 to 15 year-old boys voluntarily participated in this study. They were divided into three age groups [12-13, 13-14 and 14-15 yearold groups]. Digital photographs of the subjects' faces were taken in Natural Head Position [NHP] frontal and profile views. After determination of the landmarks, nine anthropometric parameters including nasal length, mouth width, alar width, columella width, philtrum height, nasal width, nasolabial angle, nasal root slope angle and nasal index were measured by the Smile Analyzer software considering the magnification ratio of each image. One way ANOVA and Tukey test were used for statistical analyses. Significant differences between the three groups were detected in the mean alar, mouth and philtrum widths, nose length, nasolabial angle and nasal index [P<0.05]. We did not find any significant differences in the mean nasal-root-slope angle and the mean philtrum height between the groups [P=0.29 and P=0.13, respectively]. Aging of the facial profile is not a gradual process; it occurs in spurts and at different periods of life. During the studied time span, significant growth in nose width and nose length was obvious

Correction of a severely rotated maxillary central incisor with the Whip device

The aim of this case report was to introduce an appliance that can be used for Whip device; correcting severe rotation of anterior teeth in pre-adolescent children. Severe rotation; This is a case report of an 11-year-old Iranian boy with a mixed Mesiodens dentition Class I malocclusion defined by a severe rotation of upper left central incisor and a mesi-odens between the centrals. The supernumerary tooth was first extracted, and then a Whip device including removable appliance, a cantilever spring and bonded tube on rotated tooth was inserted into his mouth. After 8 months, the upper left central incisor was orthodontically brought into proper alignment. Circumferential supracrestal fibrotomy was done next to overcorrection of the tooth and one week after surgery, the device was removed and the retention was started. The whip device, a removable appliance can be very effective for correcting severe rotation of anterior teeth