Palatal Expansion Appliance with Vertical Bone Screw Fixation
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Solution Overview
Problem
Conventional palatal expansion appliances face challenges in effectively expanding a narrow palate without applying force to teeth, particularly in adults with hardened median palatine sutures, due to limited expansion range, instability of bone screws, and discomfort caused by excessive appliance width and soft tissue contact.
Innovation Solution
A palatal expansion appliance design featuring a pair of bone screw joints with linearly arranged bone screw holes, a driving portion that moves the joints horizontally, and a narrow width to accommodate multiple bone screws near the median palatine suture, reducing twisting forces and allowing stable expansion without full soft tissue contact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If conventional palatal expansion appliances are used to expand the palate, then the palate width can be increased, but the appliance applies force to teeth which causes tooth damage and discomfort
Solution Approach 1:
The invention extracts the force application point from teeth to the median palatine suture (MPS) bone directly. The appliance includes a central element positioned on the MPS that receives expansion force directly at the bone level, eliminating the need to transfer force through tooth structures. This extraction of the force application point from the harmful location (teeth) to the target location (MPS bone) resolves the contradiction between achieving palate expansion and avoiding tooth damage.
Solution Approach 2:
The invention introduces a central element as an intermediary component that mediates between the expansion force source and the MPS bone. This central element acts as a dedicated interface for force application directly to the bone, serving as an intermediary structure that eliminates the need for force transmission through teeth. The intermediary central element with its bone-contacting surface provides a direct force application pathway that avoids harmful effects on teeth while achieving the desired palate expansion.
2Reliability
If the appliance width is increased to accommodate bone screw fixation, then stability improves, but soft tissue contact increases causing discomfort and inflammation
Solution Approach 1:
The invention transitions from a wide transverse appliance design to a narrow apical design that focuses expansion force at the midline. By changing the dimensional approach from width-based stability to depth-based force application at the MPS, the appliance achieves reliable bone screw fixation in a vertical dimension while minimizing lateral soft tissue contact. The central element's apical positioning and narrow profile allow bone screw insertion for stability without the wide soft tissue contact that causes discomfort and inflammation.
Solution Approach 2:
The invention applies local quality by concentrating the force application and bone screw fixation at the specific local region of the median palatine suture rather than distributing components across a wide area. The central element is locally positioned at the MPS with bone screw holes arranged to provide stable fixation precisely where needed. This localized approach to stability achievement minimizes overall appliance width and corresponding soft tissue contact, resolving the contradiction between reliability and comfort.
3Reliability
If multiple bone screws are inserted to prevent disassembly, then fixation stability improves, but the appliance width increases causing soft tissue contact
Solution Approach 1:
The invention arranges bone screw holes in a vertical arrangement along the central element rather than spreading them horizontally. This vertical dimensionality change allows multiple bone screws to be inserted in a stacked configuration that provides stable fixation without increasing the appliance's lateral width. The central element's narrow profile with vertically arranged bone screw holes enables reliable multi-screw fixation while maintaining minimal soft tissue contact area.
Solution Approach 2:
The invention employs a nested arrangement where multiple bone screw holes are positioned one above another along the central element's length. This nesting of bone screw positions in the vertical dimension allows multiple fixation points without lateral expansion. The compact nested configuration of bone screw holes provides enhanced fixation stability through multiple screws while keeping the appliance width minimal, thus avoiding soft tissue contact issues.
4Object-affected harmful factors
If the appliance is designed with narrow width to avoid soft tissue contact, then comfort improves, but the expansion range is limited
Solution Approach 1:
The invention employs a dynamic expansion mechanism where the central element can be rotated or adjusted to control the expansion force application. The keyhole formation portion with multiple keyholes at different positions allows dynamic adjustment of the expansion vector and magnitude. This dynamic capability enables a narrow appliance to achieve significant expansion range by varying the activation pattern and force application points, resolving the contradiction between narrow width for comfort and sufficient expansion range.
Solution Approach 2:
The invention achieves expansion range not through lateral width but through vertical positioning and rotational adjustment of the central element. The keyhole formation portion positioned apically on the central element allows force application in a vertical dimension that translates to horizontal palate expansion. This dimensional transformation enables a narrow appliance to generate sufficient expansion range by leveraging the lever arm created by the apical keyhole position and the rotational mechanics of the expansion screw.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The appliance achieves sufficient palatal expansion with reduced risk of bone screw disassembly and discomfort, enabling effective treatment of narrow palates with improved stability and ease of use, even for adults with hardened tissues.
Implementation Method 1
The screw rod 12 has threads of two types respectively formed at one end portion and the other end portion thereof in opposite directions... as each of the bodies 13 moves, each of the tooth connecting rods 15 is moved in the direction indicated by the arrow, thereby transferring a force to the teeth T
Data Source
AI summary
A palatal expansion appliance includes one pair of bone screw joints arranged to face each other, each of the one pair of bone screw joints extending in one direction and having a plurality of bone screw holes formed thereon, and a driving portion arranged between the one pair of bone screw joints, in which, as at least a part of the driving portion is moved in one direction, the one pair of bone screw joints are moved in another direction.