ONE FOR ALL , 4 FROM 1 ! – AN INNOVATION IN MAKING DENTULOUS IMPRESSIONS WITH ADJUSTABLE TRAYS

Aim: It aims to provide an easy and efficient method of recording dentulous impressions by adjusting a single tray for various mouth sizes. Settings and Design/Methods and Material: Sectioning the maxillary and mandibular tray each in three parts and attaching 3 screws (regular stainless-steel wood screws were used) in the upper and 2 screws in the lower tray was done A demonstration model for the same has been constructed with nickel-titanium screws. The objective of writing the article is to propose the idea and demonstrate the functioning of the tray. Results: The trays were sectioned, screwing and unscrewing was done (with-Taparia flat tip mini head screw driver - 10.0 x 1.2 mm) and change in tray size from number 1 to 4 and vice-versa was observed. Matrix bands were placed on the sides to provide stability to the tray and to prevent movement of the sectioned parts while in use. Conclusion: The expandable tray is an easy and effective method of recording impressions. It can be easily modified according to the clinical scenario saving on valuable clinical time and effort. Keywords: expandable tray, dentulous tray, impression making, modified perforated tray, adjustable tray

Design characteristics of perforated tray aerator

The performance of the perforated tray aerator (PTA) was evaluated by conducting experiments in a tank of size 4 m × 4 m × 1.5 m. Based on the dimensional analysis, non-dimensional numbers related to geometric variables, viz. numbers of trays (n), ratio of consecutive width of tray to total height of aerator , ratio of perforation diameter to total height of aerator and ratio of the volume of water in the tank to total height of aerator were developed. Experiments were conducted with different numbers of trays (n): 1, 2, 3 and 4, keeping = 0.33, = 2.5 × 10−4, = 2,500 and pump flow rate (Q) = 0.010 m3/s as constants. The optimum number of perforated trays was found to be 3. Response surface methodology (RSM) and central composite rotatable design (CCRD) were used to further optimize the geometric variables with combinations of non-dimensional geometric variables , and . The flow rate (Q) of 0.013 m3/s and number of trays (n) as 3 were kept as constants. The optimum performance of PTA was obtained at = 0.665, = 1.85 × 10−4 and = 312.50 with the maximum non-dimensional standard aeration efficiency (NDSAE) and standard aeration efficiency (SAE) of 35.58 × 10−3 and 1.45 kgO2/kWh.

Optimization of BS4 Enzyme production with Different Substrate Thickness and Type of Trays

BS4 enzyme that is produced from solid substrate fermentation (SSF) on coconut cake with Eupenicillium javanicum BS4 in tray bioreactor has been applied as a feed additive. It increases the nutritional value of animal feedstuff. The BS4 production on SSF may be influenced by the better aeration through the perforated trays or by the thinner substrate. The aim of this research is to optimize the production of BS4 with different substrate thicknesses and types of trays. The trial was carried out using a factorial randomized design (2x2x3) with 6 replicates. The first factor was the type of trays: i.e., non-perforated and perforated tray. The second factor was the thickness of the substrate: i.e., 1.5 and 3.0 cm, while the third factor was the duration of fermentation: i.e. 5, and 7 days. The variables observed were moisture content, dry matter loss (DML), mannanase and saccharification activities, soluble protein content, their specific activities, and yield. Statistical analysis showed no interactions between the three factors, but there were interactions between types of trays and substrate thicknesses, as well as type of trays and incubation times on the mannanase activity and yield of mannanase. The results showed that DML was observed on day 7 were around 31.43- 36.89. The highest mannanase activity was observed on the non-perforated tray with 3 cm thickness on day 7. The saccharification activity towards palm kernel meal was better in the non-perforated tray on day 7 but not influenced by The yield value of mannanase and saccharification activities on a non-perforated tray with 3.0 cm thickness on day 7 was also the highest. Based on energy efficiency and the cost of production, it can be concluded that the optimum condition to produce the BS4 enzyme was observed in the non-perforated tray with 3 cm thickness and fermented for 7 days.

IMPRESSION DIMENSIONAL CHANGE OF POLYVINYL SILOXANE LIGHT AND MEDIUM BODY MATERIAL BY USING PERFORATED TRAY

Generally impression materials including elastomer impression materials show dimensional changes after impression taking. There are many investigations that show these dimensional changes with several causal factor possibilities proposed by the authors. The actual causal factor has not been elucidated yet. The aim of this study was to find out the behaviour and dimensional changes occured in two types of elastomeric impression consistency materials by using perforated tray. Light and medium body types of polyvinyl siloxane impression materials were used in this study. Impression consistency materials were tested with the method noted at the ANSI/ ADA specification no.19-2000. Design of study post-test only. Impression was taken by using perforated metal tray on frustum conical metal master die (n= 10 impressions/material). The dimensions of samples were measured by using digital calliper (Mitutoyo, Japan) at base, top area and height. The dimensional changes were calculated from master and stone die measurement. The results showed that there were dimensional changes occured in all of observed areas. Light body type showed dimensional changes at base, top area and height as many as (+) 0.032 ± 0.016 mm, (-) 0.136 ± 0.045 mm and (+) 0.112 ± 0.022 mm, respectively. Medium body type showed dimensional changes at base, top area and height as many as (+) 0.009 ± 0.013 mm, (-) 0.090 ± 0.016 mm and (+) 0.085 ± 0.010mm, respectively. In conclusion, there were significant differences between light and medium body types of polyvinyl siloxane impression materials caused the quantity of dimensional changes on impression (p< 0.05). Stress releasing passes through the holes on perforated tray may take a possible role to cause different direction of dimensional changes on impression.