ABSTRACT
Objectives: The aims of this study were to compare the efficacy of two proven chemical disinfectants, glutaraldehyde and povidone iodine on dental impression and models by determining the reduction in the microbial load, and to compare changes in the physical properties of the models after adding the disinfectants. Materials and Methods: Irreversible hydrocolloid upper impressions of 90 patients were made and divided into 3 groups of 30 samples each; Group A––Control group; Impressions were run under clean tap water before pouring the model. Group B––2% Glutaraldehyde sprayed on the impression and left in situ for 10 min before pouring the model. Group C –10 ml of (5%) povidone iodine incorporated into the gypsum before pouring the model. Models from all three groups were subjected to microbiological assessment at three different time intervals, T0––24 h, T1––1 month and T2––3 months of storage by comparing the colony forming units (CFUs) of bacteria and fungi. The compressive strength of 5 models from each group was also analyzed in Newton’s/mm2. Results: 2% Glutaraldehyde proved more effective than povidone iodine after 24 h of storage (T1), however at the end of 1 month (T1) and 3 months (T2) the Povidone group showed the maximum disinfection. Both the disinfectants caused a reduction in the compressive strength of the model with the povidone iodine group showing the maximum reduction. Conclusion: Although povidone iodine was the most effective disinfectant after 3 months, it showed a significant reduction in the compressive strength and caused discoloration of the model. 2% Glutaraldehyde proved to be the choice of disinfectant with minimal adverse effects
ABSTRACT
In this study, we attempt to identify and trace cephalometric landmarks using two methods within the constraints of hand tracing (manual tracing). In the first method, we identify the specific landmarks pertaining to the particular structure and locate it as a continuation of the landmark tracing. In the second method, we segregate the landmarks but mark only the particular structure with a point in a way which is not too dissimilar to digitalized tracing.METHODS20 lateral Cephalograms were manually traced and analysed by the two different methods employed. Measurement obtained between the two tracings was analysed. Linear and angular measurements were taken for three cephalometric analyses, namely- Steiner’s analysis, McNamara Analysis, and Rakosi-Jarabak’s analysis.RESULTSThe analysis values were checked by the two methods of manual tracing. There seemed to be no significant difference between tracing done by locating the anatomical landmarks associated with the point and with tracing done by locating the reference points. Independent sample t-test was done to determine if any significant difference was present between the two methods of tracing.CONCLUSIONSTracing done by locating only the points after identifying the reference points is in a way, similar to how digital tracing is done. This could help put the doubts related to digitalized tracing to rest and confirm the accuracy of both the tracing methods. However, locating the anatomical landmarks along with the points could help the observer in relating to the point in an easier manner and improve the accuracy of manual tracing by inexperienced postgraduates and beginners.