Aims:To assess the sex discrimination potential of permanent maxillary molar crown widths and cusp diameters.Materials and Methods:Measurements were made on plaster casts of 200 individuals of known sex (100 males, 100 females, aged 12-21 years). Eight parameters were measured on the first and second maxillary molars with a digital caliper [buccolingual, mesiodistal, mesiobuccal-distolingual and distobuccal-mesiolingual crown widths and cusp diameters (hypocone, protocone, paracone, and metacone)]. The percentage of sexual dimorphism for each parameter was calculated. Discriminant function analysis was used to determine the accuracy of sex determination for each molar separately and both the molars taken together.Results:The highest sexual dimorphism was shown by protocone in the first molar and hypocone in the second molar. Furthermore, the sex determination accuracy was highest when the first molar was taken alone than when the second molar or the first and second molars were taken together.Conclusion:Based on this study, odontometric measurements of maxillary molars provide low to moderate sex determination accuracy.

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Aim:The purpose of this study was to evaluate the Bolton overall ratio in a north Indian population reporting for orthodontic treatment and to determine the effect of extractions on the Bolton ratios. Another aim of the study was to check the effects of different extraction patterns on the final Bolton ratio.Materials and Methods:One hundred and twenty pre-treatment dental casts (60 males and 60 females) of orthodontic patients were selected randomly. Mesio-distal dimensions of the mandibular and maxillary teeth were measured before treatment, and subjected to Bolton analysis. Hypothetical tooth extraction by the following combinations: All the first premolars, all the second premolars, upper first and lower second premolars and upper second and lower first premolars were performed for each patient. The measurement results were again subjected to Bolton analysis to see whether any tooth-size discrepancy had been created.Results and Conclusion:The tooth material ratio of the studied north Indian population shows a mild maxillary tooth material excess. Extraction of premolars in any combination causes the maxillary tooth material to further increase. There is no significant sex difference in the tooth material ratios with or without extractions. In patients requiring extraction; all first premolar extraction or maxillary first and mandibular second premolar extraction should be preferred. For deciding a treatment plan involving extraction of teeth, we need to consider that the maxillary tooth mass may increase after extraction. Furthermore, the normal or the clinically significant tooth size discrepancies may change following extraction of teeth.

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The aim of the present study was to compare the accuracy of the bracket slot dimension at base and at face and at the mesial and distal surfaces of conventional 0.022 slot metal brackets marketed by different manufacturers. Materials and methods:Twenty brackets each of 0.022 inch upper left central incisor brackets from five different manufacturers were taken for evaluation of slot dimensions with a stereomicroscope. The images obtained were calibrated with a software (Dewinter Biowizard 4.3). The bracket slot at the base and the face were measured at both the mesial and distal tie-wings. The values obtained were subjected to ANOVA and paired t-tests. Results:The size of the slots ranged from a minimum of 0.0201" to maximum of 0.0248". In general, the size of the slots was greater at the face than at the base. The mean percentage loss of symmetry from base to face for different manufacturers ranged from 2.589 to 8.958%. There was a significant difference in the slot size between the mesial and distal aspects for all the brackets except 3M and Ortho Organizer. Conclusion:The results of this study indicate that orthodontic bracket slots were different than stated by the manufacturers. All the brackets were larger at the face than at the base. Clinicians should be aware that there may be a three-dimensional loss of tooth positioning as a result of the inadvertent use of orthodontic brackets with inaccurate slots.

OBJECTIVE:To investigate the effect of different intracoronal bleaching methods on the shear bond strength and site of failure of ceramic brackets.MATERIALS AND METHODS:Sixty freshly extracted human maxillary incisors were randomly divided into four groups (n = 15). Endodontic access cavity was prepared and root canals were filled, root fillings were removed 2mm apical to the cementoenamel junction, and a 2-mmthick layer of glass ionomer cement base was applied. Group 1 served as the control. Intracoronal bleaching was performed with 35% carbamide peroxide in group 2, sodium perborate in group 3, and 37.5% hydrogen peroxide in group 4. The teeth were immersed in artificial saliva for 4 weeks before bracket bonding. Ceramic brackets were bonded with composite resin and cured with LED light. After bonding, the shear bond strength of the brackets was tested with a universal testing machine. The site of bond failure was determined by modified ARI (Adhesive Remnant Index).RESULTS:The highest value of shear bond strength was measured in control group (18.67 ± 1.59 MPa), which was statistically significant from groups 2,3, and 4. There was no significant difference between groups 2 and 4. The lowest shear bond strength was measured in group 3. ARI scores were not significant from each other.CONCLUSIONS:Intracoronal bleaching significantly affected the shear bond strength of ceramic brackets even after 4 weeks of bleaching. Bleaching with sodium perborate affects shear bond strength more adversely than does bleaching with other agents like hydrogen peroxide and carbamide peroxide.

Objective: The aim of the study was to compare and evaluate the in vitro biodegradation of nickel and chromium from space maintainers, made of three different companies, i.e (Dantaurum, Rocky mountain and Dtech) in artificial saliva.Materials and methods: The study comprised of 30 space maintainers out of which 10 were fabricated using Dantaurum, 10 using Rocky mountain and 10 using Dtech band materials. Stainless steel wire (Dantaurum, Rocky mountain and Konark) was used for making loops and Leone solder and flux was used for soldering. Each group was further divided into four subgroups containing 1, 2, 3 and 4 space maintainers respectively. The space maintainers in each subgroup were placed in separate glass beakers containing 100 ml of artificial saliva at 37°C for 4 weeks. Salivary samples from each beaker was analyzed for nickel and chromium ions separately on days 1, 7, 14, 21 and 28 days using inductively coupled plasma-optical emission spectrophotometer.Results: Total release of nickel and chromium from all band and loop space maintainers ranged from 0.020 to 1.524 ppm and 0.002 to 0.289 ppm respectively. The release of nickel and chromium between the groups and within the groups was not significant (p < 0.5).Conclusion: There was no substantial release of nickel and chromium from space maintainers made of Dantaurum, Rocky mountain and Dtech which could cause any toxicity.How to cite this article: Anand A, Sharma A, Kumar P, Sandhu M, Sachdeva S, Sachdev V. A Comparative Study of Biodegradation of Nickel and Chromium from Space Maintainers: An in vitro Study. Int J Clin Pediatr Dent 2015; 8(1):37-41.

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