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Senio r Lec t u re r Depa rtme nt of Orthodonti cs, NSVK-S ri Venkatesh wa ra Dental Coll ege, Ba ngalo re The correction of a class II malocclusion without extraction may be accomplished by expanding the arch, proclining anterior teeth, derotating' uprighting of posterior teeth, etc. O ne of the more commo n methods for creating dental arch length, without extracting teeth, has been through distalizing the maxillary posterior dentition. The present study compares the effects of Hilger's pendulum appliance and the M-Pendulum applia nce o n distalizing the upper first mo la r. It a lso attempts to know whether M-Pendulum appliance can bring about bodily movement of the molar instead of the tipping movement as produced by Hilger's pendulum appliance. In addition to these the vertical molar changes a nd the anchorage loss between the Hilger's pendulum and the M-pendulum are also evaluated.

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Joining of fixed appliance components has several applications in orthodontics. Joining attachments to archwires allows the clinician to transfer the point of force application to a location that is more advantageous from a biomechanical standpoint. Although several methods of joining attachments have been proposed, resistance spot welding and soldering have been the most commonly used procedures. Despite its common use, the literature regarding spot welding has been scarce and the technique improperly applied. The aim of this article is to describe the theory behind the use of electric spot welders and achieving an optimum weld joint. Recommendations have been made for the correct application of the parameters involved in electric resistance spot welding so that a clinically useful weld joint can be obtained.

Introduction There are various genes that affect craniofacial development and among the important genes that affect jaw development is distal-less homeobox (DLX) 6 genes. The present study was carried out to determine the role of DLX6 gene variations in mandibular deficiency. Methods Thirty subjects having retrognathic mandible were evaluated by clinical examination and assessed using lateral cephalometric radiographs based on cephalometrics for orthognathic surgery (COGS) analysis of hard tissue with N-Pog parameters being less than-13 mm. For the same subjects, saliva samples were taken and sent to biotechnology labs for genetic evaluation. DNA was isolated from salivary samples using a DNA extraction kit and was subjected to polymerase chain reaction (PCR) amplification and sequencing. Single nucleotide polymorphisms (SNP) analysis was done to assess the role of DLX6 gene in these study subjects. Results All 30 subjects showed N-POG parameters of COGS analysis for hard tissue to be less than-13mm, confirming retrognathic mandible. SNP analysis of subjects showed no SNPs in any EXON of the DLX6 gene for all 30 study samples. Conclusion No variations in DLX6 gene were found in the present study. Further studies are required to investigate other genes that could be involved in the cause of retrognathic mandible with a larger sample size and to include subjects in the sample having features other than mandibular retrognathia like hearing loss, abnormal pinnae, ectrodactyly, cleft palate, developmental delay and abnormal teeth to determine the contribution of DLX6 gene variations in mandibular deficiency.