ABSTRACT
BACKGROUND: In the past few years, there has been a major research drive to increase bond strength between dental materials and dental hard tissue and to reduce the associated demineralization around fixed orthodontic appliances. Thus, a recent approach is to incorporate an antibacterial agent into the primer to reduce the demineralization and enhance bond strength. The objective of this study was: (1) To evaluate the shear bond strength of orthodontic preadjusted edgewise appliance brackets bonded to extracted premolar teeth with antimicrobial self-etch primer (Reliance self-etching primer, Clearfil Protect Bond) and self-etching primer without antimicrobial agent (Clearfil SE bond). (2) To compare the mean shear bond strength values of the tested materials to conventional self-etching primer Transbond Plus. MATERIALS AND METHODS: A total of 125 extracted human premolar teeth were randomly divided into five groups of 25 teeth each. Each sample was embedded in an acrylic block of polymethyl meth acrylate resin till coronal portion. Instron testing machine model LR LOYD 50 K was used for testing the shear bond strength of individual samples. RESULTS: The results of the study showed that all five groups had adequate clinically acceptable bond strength. In intergroup comparison, there was statistically significant difference in bond strength of Reliance self-etching primer, Promt L pop, Clearfil Protect Bond, clearfil SE bond and Transbond Plus. CONCLUSION: Reliance self-etching primer showed highest bond strength, followed by Clearfil Protect Bond, clearfil SE bond, and Transbond Plus. Clearfil Protect Bond primer containing methacryloxy dodecyl pyridium bromide have been demonstrated to kill Streptococcus mutans within a short time of contact and also exhibits an inhibitory effect on the growth of bacteria on its surface.
ABSTRACT
BACKGROUND: The aim of this study was to verify the intra-individual reproducibility of natural head position (NHP) in centric relation (CR) position, to prove the inter-individual differences in the Frankfort horizontal plane and sella-nasion line compared with the true horizontal line, and to establish linear norms from A-point, B-point, Pog as well as soft tissue A-point, soft tissue B-point, and soft tissue Pog to nasion true vertical line (NTVL) in adult Indian subjects. METHODS: Lateral cephalograms (T1) of Angle's Class I subjects were taken in NHP and with bite in CR. A second lateral cephalogram (T2) of these subjects with ANB angle in the range 1-4° were taken after 1 week using the same wax bite and both the radiographs were analyzed based on six angular parameters using cephalometric software (Do-it, Dental studio NX version 4.1) to assess the reproducibility of NHP. Linear values of six landmarks were taken in relation to NTVL, and the mean values were calculated. A total of 116 subjects were included in this study. RESULTS: When the cephalometric values of T1 and T2 were analyzed, it was found that, the parameters showed a P < 0.001, indicating the reproducibility of NHP in CR. Mean values for point A, point B, Pog and their soft tissue counterparts were also obtained. CONCLUSION: The study proved that NHP is a reproducible and accurate when recorded with the mandible in CR. Linear norms for skeletal Class I subjects in relation to NTVL were established.
ABSTRACT
OBJECTIVE: Orthodontic diagnosis and treatment planning for growing children must involve growth prediction, especially in the treatment of skeletal problems. Studies have shown that a strong association exists between skeletal maturity and dental calcification stages. The present study was therefore taken up to provide a simple and practical method for assessing skeletal maturity using a dental periapical film and standard dental X-ray machine, to compare the developmental stages of the mandibular canine with that of developmental stages of modified MP3 and to find out if any correlation exists, to determine if the developmental stages of the mandibular canine alone can be used as a reliable indicator for assessment of skeletal maturity. MATERIALS AND METHODS: A total of 160 periapical radiographs, of the mandibular right canine and the MP3 region was taken and assessed according to the Dermirjian's stages of dental calcification and the modified MP3 stages. RESULTS AND DISCUSSION: The correlation coefficient between MP3 stages and developmental stages of mandibular canine was found to be significant in both male and female groups. When the canine calcification stages were compared with the MP3 stages it was found that with the exception of the D stage of canine calcification the remaining stages showed a very high correlation with the modified MP3 stages. CONCLUSION: The correlation between the mandibular canine calcification stages, and the MP3 stages was found to be significant. The canine calcification could be used as a sole indicator for assessment of skeletal maturity.
