RF tightening therapy transfers heat from the dermis to the subcutaneous tissue, inducing remodeling through wound healing. While this technology has a history of more than 23 years, its clinical efficacy and patient satisfaction depend not merely on being a heating device, but on how safely and efficiently heat can be delivered to deep tissues. This article systematically outlines the fundamental principles of capacitively coupled radiofrequency, the characteristics of DENSITY, and its clinical applications.
- INDEX
- Principles of High-Frequency Heating and the Role of Capacitive Coupling (01:20- )
- How Deep Heating is Achieved: The Role of Impedance and Capacitive Coupling (03:50- )
- The Innovativeness of DENSITY: Combination of Monopolar and Bipolar Technologies (10:00 -)
- Clinical Applications and Future Prospects (11:50- )
Principles of High-Frequency Heating and the Role of Capacitive Coupling (01:20- )
RF heating involves two types: Joule heating, where heat is generated by electric current, and dielectric heating, where molecular vibration caused by the electric field generates heat. Lower frequencies favor Joule heating, while higher frequencies favor dielectric heating. Capacitively coupled RF occupies an intermediate position. Devices operating at 40.68 MHz, for example, vibrate water molecules to stimulate collagen regeneration and enhanced metabolism via heat shock proteins. Skin temperature remains around 45°C, so collagen contraction like that seen with 65°C or higher is not achieved. Therefore, monopolar irradiation is often used in combination for immediate tightening effects. Unfortunately, it is said that with this type of Joule heating, simply placing the electrodes on the skin without any technique results in most of the energy being consumed in the superficial layers, with little to no heat generated in the deeper tissues.
How Deep Heating is Achieved: The Role of Impedance and Capacitive Coupling (03:50- )
To reliably deliver Joule heating deep into tissue, the impedance at the skin surface must match the impedance on the electrode side. This is achieved through “capacitive coupling.” The dielectric film formed between the electrode and skin functions as a capacitor, allowing current to flow efficiently into deeper layers without surface losses. Also, to prevent heat concentration due to the skin effect characteristic of high frequencies, Kapton film is placed at the tip to uniformly disperse energy. Furthermore, adopting the internationally approved 6.78 MHz frequency reduces the impedance of fibrous connective tissue, enabling efficient heating.
The Innovativeness of DENSITY: Combination of Monopolar and Bipolar Technologies (10:00 -)
DENSITY features an innovative design among capacitively coupled RF systems, characterized by its ability to output both monopolar and bipolar modes from a single tip. The monopolar mode delivers heat to the deep layer, while the bipolar mode targets the dermis. Switching the final pulse of a 5-pulse sequence to bipolar mode—a technique supported by research on POTENZA—enhances heat penetration due to reduced impedance after monopolar irradiation. This approach achieves both deep, long-term remodeling and immediate superficial contraction, leading to increased patient satisfaction and repeat treatment rates.
Clinical Applications and Future Prospects (11:50- )
Our clinic frequently employs a method where 200 to 300 shots are administered using the Classic Tip, followed by an additional 100 to 150 shots with the High Tip. Treatment time is short, taking about 20 minutes for 450 shots. Pain is mild, and the high patient throughput offers significant operational benefits. In our staff’s cases, facial contour tightening is evident, with visually confirmed results in nearly all cases. We also plan to introduce the new Alpha Tip, which is designed to accumulate heat more uniformly over a wider and deeper area. DENSITY, with its excellent balance of immediate results, lasting effects, and equipment investment recovery, has the potential to become the new central device for skin tightening treatments.
