ABSTRACT
Correction of dental crowding can be achieved with several orthodontic procedures like extraction of teeth, proximal stripping etc. In contemporary orthodontic practice, resolution of incisor crowding is most commonly achieved by the use of canine lacebacks. This method takes time, requires frequent activations and taxes anchorage since it involves the "PULL" mechanics. In order to overcome these disadvantages, mostly the time factor, we devised a method of using open coil NiTi spring on 0.016" SS wire piggy backed on the 0.014" heat activated NiTi base arch wire ligated only at the canines. This method, resolved the incisor crowding in almost one third of the time taken with the use of canine lacebacks. Moreover, the result was more physiologic since light continuous force was applied with the spring and it essentially eliminated the anchorage loss since it involved "PUSH" mechanics.
ABSTRACT
INTRODUCTION: The clinician's skill, impression techniques, and materials play a very important role in recording fine details in an impression for accuracy of fixed partial denture prosthesis. Impression of prepared teeth and of the opposing arch can be recorded simultaneously by dual-arch trays, while the full arch metal trays are used for impressions of prepared teeth in one arch. AIM: To measure and compare the accuracy of working dies made from impressions with metal and plastic dual arch trays and metal full arch trays, for two viscosities of impression material and by changing the sequence of pour of working and non-working sides. MATERIALS AND METHODS: A balanced design with independent samples was used to study the three variables (tray type, impression material viscosity, and pouring sequence). An impression made by dual arch trays and single arch trays were divided in to three groups (Group A-plastic dual arch tray, Group B-metal dual arch tray, Group C-full arch metal stock tray). Out of these three groups, two groups (Group A and B) were subdivided in to four subgroups each and one group (Group C) was subdivided in to two subgroups. A sample size of 30 was used in each subgroup yielding a total 300 impressions in three groups or ten subgroups. Impressions were made of a machined circular stainless steel die. All three dimensions (Occlusogingival, Mesiodistal, and Buccolingual) of the working dies as well as stainless steel standard die were measured three times, and the mean was used for the three standard sample values to which all working dies means were compared. Statistical analysis used for this study was a 3-factor analysis of variance with hypothesis testing at α =0.05. RESULTS: With respect to the selection of impression material viscosity statistically significant differences were found in the dies for the buccolingual and mesiodistal dimensions. Metal dual arch trays were slightly more accurate in the mesiodistal dimension in comparison to the plastic trays in reference of tray selection and in view of pouring sequence no differences were observed in occlusogingival dimension but in buccolingual and mesiodistal dimensions nonworking side was more accurate. CONCLUSION: The gypsum dies produced from the dual arch impressions were generally smaller in all three dimensions than the stainless steel standard die. Plastic dual-arch trays were more accurate with rigid impression material and there was not statistically significant difference for sequence of pouring. Metal dual-arch trays were more accurate with monophase impression material and working side was more accurate. Stock metal full arch trays were more accurate for monophase impression material.
ABSTRACT
Separation of teeth is an important and integral aspect of orthodontic treatment. Elastomeric separators are the most common devices used today which require special instrument to place them. The purpose of this study was to design a separator placing instrument of dental probe/explorer which can be used as an alternative to the special instrument required. The materials required were two dental probes/explorers, a light wire plier and elastomeric separators. The modified instrument made is easy to fabricate, inexpensive and can partially or completely replace the special separator placing plier.
