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Radio Microsurgery Update: Troughing and Impression Taking

Dr. Irving Ellman, electrical engineer, inventor, and doctor of dental surgery, patented in 1976 a high-frequency radio wave generator using 3.8 MHz and a fully rectified current. For centuries, man has used sharpened instruments to incise tissue. After the advent of electricity, various electric modalities were applied to tissue for hemostasis and incision. The use of electricity in dentistry and medicine has come a long way from spark gap generators (1907),1 electrocautery (1909),2 and electrosurgery (1928).3
In 1972, after having worked with the new Ellman High Frequency 3.8 MHz Radio Wave Generator, I created the International Academy of Radiosurgery and defined the word radiosurgery as the use of high-frequency radio waves of 3.8 MHz to incise, sculpt, ablate, or coagulate tissue. Until 1972 the “advantages” of electrosurgery (high heat, hot electrode) were that one could operate with some control of coagulation. The emphasis was on coagulation, not on incision. With the advent of Ellman technology it became possible to incise with an electrode as with a scalpel, which was not possible with electrosurgery.4,5 Hence, dental office closets were filled with discarded electrosurgical units.
Ellman state-of-the-art technology today uses patented generators of 4 MHz (Figure 1) and new alloy electrodes (advanced composite electrodes [Ace]) that create a harmonic field, resulting in physiologically compatible tissue vaporization and negligible tissue alteration. The electrode is cold. Leaders in surgical innovation throughout the world in all surgical disciplines—arthrosurgery, ophthalmology, facial plastic surgery, dermatology, pediatric neurosurgery, endoscopic spine surgery, otolaryngology, gynecology, proctology, and dentistry—are using Ellman technology, which continues to evolve by responding to requirements and wishes of those who experience the satisfaction of relaxed, successful, anxiety-free practice.6-22


Figure 1. Dento-Surg 90 F.F.P.

Figure 2. Retraction cords.

Troughing by definition is  the preparation of gingival tissue by cell vaporization prior to taking impressions of teeth that have been prepared to receive a dental prosthesis. Whether taking impressions with a dental impression material or with optics, it is very stressful, both for the dentist and the patient, to miss a margin and have to redo an impression or a finished prosthesis. I remember in the past using dental plaster to take impressions in the mouth, breaking the plaster in the mouth, then reattaching it to make a working model. If one did not want to use plaster, there were always copper tubes with a compound material, which was a long, tedious procedure necessitating multiple transfers, and it was not always kind to the gingival tissue. As often as not, the periodontal attachment was impinged upon. All of this was very time consuming, often frustrating, and always stressful. With the introduction of elastomers life became a bit easier, but the problem of reproducing multiple preparation margins in a manner that did not impinge upon the periodontal attachment as with the time-consuming, frustrating use of cotton cords with or without some vasoconstrictor and/or coagulating agent was not solved. Very often gingival contraction after prosthetic cementation occurred due to injury of the gingival attachment during the placement of “retraction cords” (Figure 2).
Troughing with radiosurgery (low heat, controlled coagulation) has “destressed” that which was always an anxious, stressful experience. With radiosurgery it is possible to expose with ease tooth preparation margins for excellent, predictable elastomer or optical impressions.

Troughing Guidelines23,24

Figure 3. Ace Vari-Tip 0.007 electrode.

Figure 4. Troughing 1.

Figure 5. Troughing 2.

Figure 6. Troughing 3.

Figure 7. Troughing 4.

Figure 8. Troughing 5.

1. Electrode Movement:

• Use finger rest or hand support.
• Use short, precise, perpendicular strokes.
• Use light “brush-like“ strokes.
• Do not remain motionless in tissue.
• The slower the movement, the more lateral heat and coagulation.

2. Electrode selection:

• Anterior teeth—depending upon tissue thickness an Ellman new proprietary Ace Vari-Tip 0.007 to 0.010 electrode (Figure 3). Do not destroy epithelial attachment.
• Posterior teeth—depending upon tissue thickness an Ellman new proprietary Ace Vari-Tip 0.010 to 0.014 electrode.
Probe the sulcus depth with a nonactivated Vari-Tip electrode and adjust the electrode tip to a depth just short of the sulcus depth while resting the Teflon tube of the Vari- Tip on the finish line of the tooth preparation. Wipe the gingival tissue on the inside of the gingival sulcus (Figures 4 to 8) with the energized electrode. Do not destroy epithelial attachment.

3. Do not trough in hyperemic tissue. To do so would be “periodontal treatment” with subsequent tissue retraction upon healing.

4. Use a fully rectified filtered frequency wave and control coagulation with speed of electrode movement, energizing the electrode prior to tissue contact.

5. Use the minimum amount of current necessary to vaporize the tissue easily. If tissue vaporizes “white” or “sticks” to the electrode, there is insufficient current. If there is sparking, there is too much current. Set the Ellman Radiolase II unit in monopolar mode to “cut” and 1.75. Adjust the current amplitude up or down from there.

6. Injecting a local anesthetic directly into the tissue immediate to the troughing site will increase the amount of electrolyte in the tissue, thereby reducing the amount of current required for optimal tissue vaporization.

7. Irrigate the troughed area with 5% volume hydrogen peroxide, rinse carefully with water, lightly air dry, and take impression with elastomer material or optics.

8. Apply Ellman Corporation Tincture of Myrrh and Benzoin (a liquid band-age) to troughed area prior to cementation of the temporary prosthesis.


Figure 9. Prepared and troughed.

Figure 10. Ten days after impression.

Figure 11. Five years postoperative.

Figure 12. Five years postoperative; closeup of Figure 11.

Troughing with the Ellman high-frequency/low temperature RF energy source and new low-heat proprietary Ace electrodes25 is a safe,26 predictable, economic, and stress-free technique to prepare gingival tissue for impressions, be it with elastomers or optics. Margins of preparations are clearly visible and accessible (Figures 9 to 12). It should not be performed with high-heat, low-frequency electrosurgical units. The new low-heat proprietary Ellman Ace electrodes are not compatible with other brand generators, as the subsequent harmonic fields do not lend themselves to optimal tissue vaporization.


  1. Pollack SV, Carruthers A, Grekin RC. The history of electrosurgery. Dermatol Surg. 2000;26:904-908.
  2. Doyen D. Sur les destruction des tumeurs cancéreuses accessibles par la méthode de la voltaïsation bipolaire et de l’électrocoagulation thermique. Arch Elec Med. 1909;17:1791-1795.
  3. Bovie WT. New electro-surgical unit with preliminary note on new surgical current generator. Surg Gynecol Obstet. 1928;47:751-784.
  4. Maness WL, Roeber FW, Clark RE, et al. Histologic evaluation of electrosurgery with varying frequency and waveform. J Prosthet Dent. 1978;40:304-308.
  5. Turner et al. Analysis of tissue margins of core biopsy specimens obtained with “cold knife”, co2 and Nd:yag lasers and Radiosurgical unit. J Reproductive Med. 1982;
  6. Guillaume B. Contribution of radiosurgery to implantology. J Implant. 2005, Elsevier.
  7. Davidoff SR. Developing soft tissue contours for implant-supported restorations: a simplified method for enhanced aesthetics. Pract Periodontics Aesthet Dent. 1996;8:
  8. Ferris RT. Periodontal-flap management is improved with radiosurgery. Dent Econ. 1993;83:96-97.
  9. Brown JS. Radio surgery for minor operations in general practice. Cosmetic Dermatol. July 2000:33-36.
  10. Weinstein S. Gyn. Dept. Univ. of Texas, Vaginal lip and labia reduction: personal communication, August 14, 2007. 
  11. Cohen A. Pediatric brain and spinal neurosurgeon, Cornell Univ, and head of neurosurgery, Brooklyn Hosp, NY: personal communication, June 5, 2001.  
  12. Niamtu J. 4 MHz radiowave applications in cosmetic facial surgery. Cosmetic Dermatol. November 2003; 16(11):33-46.
  13. Hurwitz JJ, Johnson D. High-frequency radio wave electrosection of full-thickness eyelid tissues. Can J Ophthalmol. 1993;28:28-31.
  14. Deshpande B. Ellman radiosurgery unit: an excellent treatment for biopsy on skin lesions. Personal communication, January 2006. 
  15. Older JJ. Review: the value of radiosurgery in oculoplastics. Ophthal Plast Reconstr Surg. 2002;18:214-218.
  16. Nikolayev MP, Ulyanov YP, Kutin GA, et al. Role of radiosurgery in otorhinolaryngology. Int Med J. 1998;11/12:933-935.
  17. Associated Press. Peru’s ‘mermaid’ baby celebrates first birthday. http://www.msnbc.msn.com/id/7681201/. Published April 29, 2005. Accessed October 11, 2007.
  18. Goodrich JT, Staffenberg DA. Cranio-pagus twins: clinical and surgical management. Childs Nerv Syst. 2004;20:618-624.
  19. Ragab SM. The effect of radiosurgery and mitomycin C on the closure rate of human tympanostomy. Otol Neurotol. 2005;26:355-360.
  20. Shehata MS, Ragab SM, Behiry ABS, et al. Telescopic-assisted ra-diofrequency adenoidectomy: a prospective randomized controlled trial. Laryngoscope. 2005;115:162-166.
  21. Bersnev VP, Solovyev AN, Gulyaev DA. Brain tumour removal using radiowave surgical device Ellman “Surgitron”; Russian Neurosurgical Research Institute, St. Petersburg, Materials of Polenov Readings, January 16, 2006. 
  22. Anders JC. High frequency radiosurgery: novel energy source for intracranial neurosurgery with monopolar indications; Abstract, Japan Neurosurgery Association, December 2006.
    23. Goldstein AA. Radiosurgery In Dentistry. Journal Dentaire Du Québec.1977;xiv:32-39.
    24. Goldstein AA. Radiosurgery In Dentistry Journal Dentaire Du Québec. 1977;xiv:36-45.
    25. Shoji T. Kansai Electric Power Hospital, Osaka, Japan Japan Seminar of Clinical Radiosurgery.
    26. Silverman EB, et al. Histologic comparison of canine skin biopsies collected using monopolar electrosurgery, CO2 laser, radiowave radiosurgery, skin biopsy punch, and scalpel. Vet Surg. 2007;36:50-56.

Dr. Goldstein graduated from Northwestern University dental school in 1961 and served as a full-time instructor in operative dentistry at the Royal Dental College of Denmark in Aarhus, Denmark, until 1963. Since then he has maintained a private practice in the principality of Monaco. He is a Fellow of the AGD and the International College of Dentists, founder and president of the International Academy of Radiosurgery, and a Founding Member and Fellow of The International Academy of Gnathology – European Section. He is widely published, and has presented more than 150 courses on the topic of radiosurgery. He can be reached at This email address is being protected from spambots. You need JavaScript enabled to view it. or by visiting dragoldstein.com.

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