Dental Muffle Cooling via Phase Transition Enthalpy

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Solution Overview

Problem

Current dental cooling methods are either too slow, risk stress cracks in the muffle, or damage the dental restoration due to uneven cooling and excessive material removal, and are economically inefficient.

Innovation Solution

A method involving a cold liquid medium that penetrates only the outer areas of the muffle, utilizing phase transition enthalpy for rapid and uniform cooling, ensuring even heat absorption without contact with the restoration parts, using a latent heat storage device to manage thermal energy effectively.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If cooling with a fan is used to accelerate cooling, then cooling speed is improved, but uniformity of cooling deteriorates creating local temperature gradients

Engineering Contradiction:

Improvecooling speedVSAvoidtemperature uniformity

Core Design Contradiction:

SpeedVSStability of the object's composition

Solution Approach 1:

The patent applies phase transition of water (liquid to vapor) as the cooling mechanism. Water is applied to the muffle surface, absorbs heat through evaporation, and transitions to vapor, providing rapid and uniform cooling across the entire surface without creating local temperature gradients.

Inventive Principle:

Principle #36Phase transitions

Solution Approach 2:

The patent uses hydraulic principles by applying liquid water to the muffle surface through a spray system. The water flows over the surface and evaporates, providing a uniform cooling distribution that avoids the localized cooling problems of fan-based air circulation.

Inventive Principle:

Principle #29Pneumatics and hydraulics

2Speed

If sandblasting is used to split the muffle while hot to improve cooling, then cooling speed is improved, but damage to the dental restoration increases

Engineering Contradiction:

Improvecooling speedVSAvoiddamage to dental restoration

Core Design Contradiction:

SpeedVSObject-affected harmful factors

Solution Approach 1:

The patent uses the phase transition of water (evaporation) as a gentle cooling mechanism that does not mechanically impact the dental restoration. The water evaporates from the muffle surface, absorbing heat without physically contacting or damaging the embedded restoration components.

Inventive Principle:

Principle #36Phase transitions

Solution Approach 2:

The patent introduces water as an intermediary cooling medium between the hot muffle and the external environment. This intermediary absorbs the thermal energy through evaporation, providing cooling without direct mechanical contact that would damage the dental restoration.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Speed

If complete immersion cooling is used, then cooling speed is improved, but quality of the dental restoration deteriorates due to uneven cooling

Engineering Contradiction:

Improvecooling speedVSAvoidrestoration quality

Core Design Contradiction:

SpeedVSManufacturing precision

Solution Approach 1:

The patent utilizes the phase transition of water (evaporation) occurring at the muffle surface to provide rapid cooling. This surface-level evaporation cooling is more uniform and controlled compared to complete immersion, preventing thermal shock and ensuring consistent temperature distribution that preserves restoration quality.

Inventive Principle:

Principle #36Phase transitions

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

This approach enables rapid, uniform, and material-friendly cooling, reducing the risk of stress cracks and economic disadvantages, achieving cooling times significantly shorter than traditional methods without compromising the quality of the dental restoration.

Implementation Method 1

The medium, especially if liquid, penetrates the outer surfaces of the muffle, preferably only the outer third or at most the outer half, so that no contact can occur between the medium and the dental restoration components. According to the invention, it is provided to utilize the additional enthalpy required at a phase transition temperature of the medium.

Methodology Applied

Scientific EffectPhase transition enthalpy: Latent Heat

Implementation Method 2

The phase transition considered here occurs from solid to liquid and from liquid to gaseous. The thermal energy of the muffle is essentially converted into the enthalpy of vaporization and/or fusion of the medium and is thus consumed, so that heat is intensively extracted from the muffle.

Methodology Applied

Scientific EffectEvaporation: Evaporation

Implementation Method 3

Due to the intensive thermal contact, the medium is heated to the phase transition temperature, and preferably even beyond. This automatically utilizes the phase transition enthalpy of the medium.

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP3669821B1Dental cooling method

Publication Date: 2023.06.21 IVOCLAR VIVADENT AG

Figure 1~2(d)
Figure 3~4

AI summary

A dental cooling device is provided, comprising a muffle (12) and a medium (30) as a cooling source. The medium (30), in particular a liquid medium (30), is stored at least in the outer region of the muffle (12) and has an evaporation temperature higher than room temperature. The quantity of the medium (30) is pre-calculated such that the enthalpy of vaporization of the medium is substantially destroyed or consumed when the muffle (12) is cooled to the evaporation temperature.