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In vitro study of a mandibular implant overdenture retained with ball, magnet, or bar attachments: comparison of load transfer and denture stability
THE JOURNAL OF PROSTHETIC DENTISTRY
excess (Fig. 1). The extension of the wax (indicated by straight arrows) will help to form a notch required to remove the processed acrylic resin sprues (Fig. 1). 3. Remove the wax with hot water to form the mold (Fig. 2, A). 4. Apply separating medium (Cold mold seal, Dental Products of India Ltd; Mumbai, India) to the mold space and pour autopolymerizing resin (Dental Products of India Ltd; Mumbai, India) into the mold space. 5. After the acrylic resin has set remove the patterns and trim the excess resin (Fig. 2, B). The measuring scale will help to select the sprue of desired length.
FERNANDES AND COELHO
2. Mirfazaelian A, Mangoli AA. Easy way to prepare plastic sprues for dowel fabrication. J Prosthet Dent 2000;83:486. Reprint requests to: DR AQUAVIVA S. FERNANDES SEBASTIAN VILLA AVEDEM PO QUEPEM, GOA 403705 INDIA E-MAIL: [email protected] Copyright © 2003 by The Editorial Council of The Journal of Prosthetic Dentistry. 0022-3913/2003/$30.00 ⫹ 0
REFERENCES 1. Shillingburg HT Jr, Hobo S, Whitsett LD, Jacobi R, Brackett SE. Fundamentals of fixed prosthodontics. 3rd ed. Chicago: Quintessence; 1997. p. 214.
Noteworthy Abstracts of the Current Literature
doi:10.1016/S0022-3913(03)00236-1
In vitro study of a mandibular implant overdenture retained with ball, magnet, or bar attachments: comparison of load transfer and denture stability Masahiro Tokuhisa, Yasuyuki Matsushita, and Kiyoshi Koyano. Int J Prosthodont 2003;16:128-134.
Purpose. When implants are used to support a removable overdenture, the optimal stress distribution to minimize both forces on the implants and denture movement is desirable. This study compared the stress patterns generated around implants and denture movement among three retention systems. Materials and Methods. Two root-form implants were anchored in a mandibular model made of resin, and a removable overdenture on which all experiments were performed was fabricated. The surface of the model was covered with a layer of impression material to simulate oral mucosa. Ball/ O-ring, bar/clip, and magnetic attachments were used. A vertical force was applied to the left first molar and gradually increased from 0 to 50 N in 5-N steps. The resultant stress distribution and denture movement were evaluated. Results. The ball/O-ring attachment transferred the least stress to both implants and produced less bending moment than the bar/clip attachment. Vertical force applied to the bar/clip attachment created immediate stress patterns of greater magnitude and concentration on both implants. Conclusion. This in vitro study suggested that the use of the ball/O-ring attachment could be advantageous for implant-supported overdentures with regard to optimizing stress and minimizing denture movement.—Reprinted with permission of Quintessence Publishing.
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excess (Fig. 1). The extension of the wax (indicated by straight arrows) will help to form a notch required to remove the processed acrylic resin sprues (Fig. 1). 3. Remove the wax with hot water to form the mold (Fig. 2, A). 4. Apply separating medium (Cold mold seal, Dental Products of India Ltd; Mumbai, India) to the mold space and pour autopolymerizing resin (Dental Products of India Ltd; Mumbai, India) into the mold space. 5. After the acrylic resin has set remove the patterns and trim the excess resin (Fig. 2, B). The measuring scale will help to select the sprue of desired length.
FERNANDES AND COELHO
2. Mirfazaelian A, Mangoli AA. Easy way to prepare plastic sprues for dowel fabrication. J Prosthet Dent 2000;83:486. Reprint requests to: DR AQUAVIVA S. FERNANDES SEBASTIAN VILLA AVEDEM PO QUEPEM, GOA 403705 INDIA E-MAIL: [email protected] Copyright © 2003 by The Editorial Council of The Journal of Prosthetic Dentistry. 0022-3913/2003/$30.00 ⫹ 0
REFERENCES 1. Shillingburg HT Jr, Hobo S, Whitsett LD, Jacobi R, Brackett SE. Fundamentals of fixed prosthodontics. 3rd ed. Chicago: Quintessence; 1997. p. 214.
Noteworthy Abstracts of the Current Literature
doi:10.1016/S0022-3913(03)00236-1
In vitro study of a mandibular implant overdenture retained with ball, magnet, or bar attachments: comparison of load transfer and denture stability Masahiro Tokuhisa, Yasuyuki Matsushita, and Kiyoshi Koyano. Int J Prosthodont 2003;16:128-134.
Purpose. When implants are used to support a removable overdenture, the optimal stress distribution to minimize both forces on the implants and denture movement is desirable. This study compared the stress patterns generated around implants and denture movement among three retention systems. Materials and Methods. Two root-form implants were anchored in a mandibular model made of resin, and a removable overdenture on which all experiments were performed was fabricated. The surface of the model was covered with a layer of impression material to simulate oral mucosa. Ball/ O-ring, bar/clip, and magnetic attachments were used. A vertical force was applied to the left first molar and gradually increased from 0 to 50 N in 5-N steps. The resultant stress distribution and denture movement were evaluated. Results. The ball/O-ring attachment transferred the least stress to both implants and produced less bending moment than the bar/clip attachment. Vertical force applied to the bar/clip attachment created immediate stress patterns of greater magnitude and concentration on both implants. Conclusion. This in vitro study suggested that the use of the ball/O-ring attachment could be advantageous for implant-supported overdentures with regard to optimizing stress and minimizing denture movement.—Reprinted with permission of Quintessence Publishing.
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VOLUME 90 NUMBER 2