|
KMID : 0362419940320020327
|
|
Journal of Korean Academy of Prosthodontics
1994 Volume.32 No. 2 p.327 ~ p.358
|
|
|
Photoelastic stress analysis on the mandible caused by implant overdenture.
|
|
Kang Jeong-Min
Vang Mong-Sook
|
|
|
Abstract
|
|
|
|
This study was performed to evaluate the effects of number and alignment of implant fixture and various bar designs on the retention of denture and the stress distribution. Six kinds of photoelastic mandibular models and nine kinds of overdenture specimens were designed. A unilateral vertical load was gradually applied on the right first molar to calculate the maximal dislodgement load of each specimen. A unilateral vertical load of 17 Kgf was applied on the right first molar and a vertical load of 10 Kgf was applied on the interincisal edge region. The stress pattern which developed in each photoelastic model was analyzed by the reflection polariscope. The results obtained were as follows: 1. The maximal dislodgement load reversely increased with the distance from the lading point to the implant fixture, while it linearly increased with that from the most posterior implant fixture to the mesial clip. The maximal dislodgement load also increased with the use of a cantilever bar. 2. Under the posterior vertical load, the stress to the supporting tissue of the denture base increased with the distance from the loading point to the implant fixture. The stress concentration on the apical area of the implant fixture reversely increased with the distance from the loading point to the implant fixture. 3. In the overdentures supported by two implant fixtures under the posterior vertical load. the specimen implanted on lateral incisor areas with a cantilever bar exhibited more favorable stress distribution than that without a cantilever bar. The specimen implanted on the canine areas without a cantilever bar, however, exhibited more favorable stress distribution. 4. In the overdentures supported by more favorable stress distribution than that implanted on the midline and the first premolar areas. 5. In the overdentures supported by four implant fixtures, the specimen implanted with two adjacent implant fixtures exhibited more favorable stress distribution than that implanted at equal distance under the posterior vertical load. 6. Under the anterior vertical load, the overdentures supported by three implant fixtures exhibited stress concentration on the supporting structure of the middle implant fixture. In overdentures supported by two or four implant fixtures, no significant difference was noted in stress distribution between the types of bars. These results indicate that the greater the number of implant fixtures, the better the stress distribution is. A favorable stress distribution may be obtained in the overdentures supported by two or three implant fixtures, if the location and the design of the bar are appropriate.
|
|
|
KEYWORD
|
|
|
|
|
|
FullTexts / Linksout information
|
|
 
|
|
|
Listed journal information
|
|
 
|