Stress analysis of implant-supported overdenture and effect of position and number of implants
Complete Denture
Complete denture is one of the dental treatment for edentulous patients.
Complete denture is an artificial denture placed in the mouth to restore masticatory function of edentulous patients.
Complete denture[1]
However, complete denture is fitted and bonded to the shape of mouth, so the are vulnerable to lateral forces and are prone to shifting from side to side.
Implant Overdenture
Implant overdenture (IOD) is a treatment in which 2-4 dental implants are placed in patient's jawbone, and the implants are used as support devices to hold the denture in place.
The denture part of IOD is removable from the implants for easy maintenance.
Structure of IOD[2]
Compared to complete dentures, IOD is less likely to shift when lateral force are applied because the denture is held in place by the implants. It also reduce the risk of spontaneous falling off.
However, bacause IOD is supported by a small number of implants, the denture can't be used if even one implant fails, whish has the disadvantage of causing malocclusion. Therefore, the type, placement position, and number of implants appropriate for the patient must be established at the time of implant placement.
Placement Position of Implant
Currently, the positioning of implants for IOD is still controversial, especially for the maxilla,
and guidelines have been made for anterior-posterior placement in a wide and polygonal fashion[3], but the mechanical evidence is lacking.
The actual insertion location is set based on the dentist's experience and clinical practice.
Example of implant placement for maxillary IOD[4]
Reverse Engineering
In this study, reverse engineering was used as a method to create a 3D model of the jawbone, which is a complex shape.
Reverse engineering is a method of taking data on the shape of an actual object and creating a 3D model based on it.
Stress analysis was performed using the model created by this method.
Necessity of Stress Analysis in This Study
As noted above, it is debatable what placement conditions are less burdensome to the patient in implant overdenture.
Currently, the placement position and number of implants is determined based on the physician's experience and clinical practice.
In this study, 3D models were created by setting the placement position and number of implants and placing them in several edentulous jaw cases.
Using this model, stress analysis was performed to evaluate the effects of stress distribution on the maxilla and denture under various conditions,
enabling the appropriate placement position and number of implants to be set.
Purpose of Research
Stress analysis is performed to evaluate the relationship between the position and number of supporting implants
and the stress distribution in implant overdentures and the optimal conditions for implant placement.
Slides
[1]ひかり歯科クリニック
http://www.gerontogical-dental.com/esthetic/full-dentures
[2]たかやまデンタルクリニック
http://www.katayama-dental.com/14399052915864
[3]口腔インプラント治療指針2020
https://www.shika-implant.org/publication/dl/2020_guide.pdf
[4]知っておくべきインプラントオーバーデンチャー これからのスタンダード
https://www.shien.co.jp/book/sample/s3/8124.pdf