Quantitative and qualitative analysis of multiple unit titanium dental castings
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The past decade has shown an increase in the use of Titanium (Ti) for removable partial dentures (RPD). However, its use for crown and bridge procedures has been minimal due to internal porosity and lack of marginal accuracy. Wax bridges were fabricated on a metal analog that simulated a three unit bridge.Titanium castings (N=70) were made using an Argon/arc/vacuum/pressure machine (Cyclarc, J. Morita Co., Osaka, Japan). The resultant castings (ten/group) were analyzed as follows: (1) radiographic inspection for degree of porosity by four sprue designs (runner bar, runner bar with constriction, overall single sprue, individual unit sprue); (2) marginal accuracy by modifying burnout temperatures (BT: 910 degrees C, 920 degrees C, 930 degrees C); (3) marginal gap was measured and evaluated with a Nikon Measurescope MM-11 (Nikon Inc., Garden City, NY) (4) statistical comparison was made using Eclipse (J. M. Ney Co., Bloomfield, CT) as a control group. The following results were obtained: (a) porosity was less when a large individual unit sprue (6 gauge) was used , but the comparison with other sprue designs were suggestive of significance (p[less than]0.10) by Wilcoxon Rank Sum test; 0,) The Eclipse castings (marginal gap: 29:9[plus or minus]10.8pr) were statistically better than the titanium castings at selected temperatures (BT: 910 degrees C--39.7[plus or minus]13.0[mu], BT: 920 degrees C— 43.2[plus or minus]11.0[mu]BT: 930 degrees C--51.9[plus or minus]13.0[mu]by one way ANOVA at p[less than]0.001 and followed by the LSD multiple comparison procedure. (c) Also noted that the lower burnout temperatures 910 degrees C and 920 degrees C for titanium exhibited significantly smaller marginal gaps than the higher temperature 930 degrees C (p=0.003 and p=0.028 by LSD). These data show that titanium is a clinically acceptable substitute alloy when a proper waxing and casting regime is followed.
PLEASE NOTE: This work is protected by copyright. Downloading is restricted to the BU community: please click Download and log in with a valid BU account to access. If you are the author of this work and would like to make it publicly available, please contact firstname.lastname@example.org.Includes bibliography: (leaves 82-91).Thesis (D.Sc.D.)--Boston University, Henry M. Goldman School of Graduate Dentistry, 1994 (Prosthodontics).
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