There are situations in which it may not be feasible or desirable to manage the gingiva with retraction cord alone. Even if the general condition of the gingiva in a mouth is healthy, areas of inflammation and granulation tissue may be encouered around a given tooth. This can be caused by overhangs on previous restorations or by the caries itself. It may have been necessary to place the finish line of the preparation so near the epithelial attachment that it is impossible to retract the gingiva sufficiently to get an adequate impression. In these cases, it may be necessary to use some means other than cord impregnated with chemicals to gain access and stop minor bleeding.
The use of electrosurgery has been recommended for enlargement of the gingival sulcus and control of hemorrhage to facilitate impression making. Strictly speaking, electrosurgery cannot stop bleeding once it starts. If hemorrhage occurs, it first must be controlled with pressure and/or chemicals, and then the vessels can be sealed with a coagulating ball electrode.
Electrosurgery has been described for the removal of irritated tissue that has proliferated over preparation finish lines, and it is commonly used for that purpose. There has been concern expressed about the use of electrosurgery on inflamed tissue, be used on exaggerated response to an electrosurgical procedure. Proximity to bone and lateral heat production may have been responsible for the response. Bone is very sensitive to heat.
Electrosurgery is unquestionably capable of tissue damage, Most surgical instruments are dangerous if used improperly. Tremendous iatrogenic damage has been done over the years by the rotary handpiece, but no one has suggested that it not be used. Kalkwarf et al reported that wounds created by a fully rectified, filtered current in the healthy gingiva of adult males demonstrated epithelial bridging at 48 hours and complete clinical healing at 72 hpurs. In a double-blind study on 27 patients. Aremband and Wade detected no difference in healing in gingivectomies done by scalpel or electrosurgery. When variables are properly controlled in electrosurgery. Untoward events in wound healing are rare.
An electrosurgery unit is a high-frequency oscillator or radio transmitter that uses either a vaccum tube or a transistor to delver a high-frequency electrical current of at least 1.0 MHZ (one million cycles per second). It generated heat in a way that is similar to a producing heat in muscle tissue for physical therapy. Electrosuregy has been called surgical diathermy.
Credit for being the direct progenitor of electrosurgery is generally given to d’Arsonval.
His experiments in 1891 demonstrated that electricity at ;high frequency will pass through a body without producing a shock (pain or muscle spasm_, producing instead an increase in the internal temperature of the tissue. This discovery was used as the basis for the eventual development of electrosurgery.
Electrosurgery produces controlled tissue destruction to achieve a surgical result. Current flows from a small cutting electrode that produces a high current density and rapid temperature rise at its point of contact with the tissue. The cells directly adjacent to the electrode are destroyed by this temperature increase. The concentrates at points and sharp bends. Cutting electrodes are designed to take advantage of this property so they will have maximum effectiveness. The circuit is completed by contact between the patient and a ground electrode that will not generate heat in the tissue because its large surface area produces a low current density, even though the same amount of current passes
through it. The cutting electrode remains cold, this differs from electrocautery, in which a hot electrode is applied to the tissue.
Types of Current:
There are different forms of current that can be generated for electrosurgical use, depending on the type of machine (and circuitry) used or the setting on any given machine. These current exhibit different wave forms when viewed on an oscilloscope. They are significant because each produces a different tissue response
The unrectified, damped current is characterized by recurring peaks of power that rapidly diminish. It is the current produced by the old hyfurcator or spark gap generator, an it given rise to intense dehydration and necrosis. It causes considerable coagulation, and healing is slow and painful.
Sometimes referred to as the Oudin or Telsa current. It is not used routinely in dental electrosurgery today.
A partially rectified, damped (half-wave modulated) current produces a wave form with a damping in the second half of each cycle. there is lateral penetration of heat, with slow healing occurring in deep tissues. The damping effect produces good coagulation and hemostatis but tissue destruction is considerable and healing is slow.
A better current for enlargement of the gingival sulcus is found in the fully rectified (full-wave modulated) current that produces a continuous flow of energy. Cutting characteristics are good and there is some hemostasis.
The fully rectified, filtered is a continuous wave that produces excellent cutting. Healing of tissues cut be a continuous wave current will be better initially than tissues cut by a modulated wave.
The continuous wave produces less injury to the tissue than does a modulated wave. However, a controlled histologic study found that after 2 weeks, haling of wounds produced by filtered current was nor remarkably better than healing of wounds produced by nonfiltered full-wave modulated current.
Filtered current probably produces better healing in situations requiring an incision and healing by primary intention, because there is less coagulation of the tissues in the walls of the wound. This is not critical in those procedures done in conjuction with restorative dentistry, when
either the inner wall of the gingival sulcus is removed, or modified gingivosplasty is accomplished by planning the surface of the tissue. In thsese cases, hemostatis is required, and moderate tissue coagulation is not only tolerated but desired.
Grounding:
For the patients safety, it is important that the circuit be completed by the use of the ground electrode, which is also known as a g round plate, indifferent plate, indifferent electrode, neutral electrode, dispersive electrode, passive electrode, or patient return. Some dentists, prompted by the unfortunate advertising of a few electrosurgical manufactures, have chosen to dispense with the used of this vital piece of equipment. An electrosurgery unit will work without one, but it is neither as efficient nor as safe.
Grounding the chair is not an acceptable alternative. Current will be dissipated through the path of least resistance, and patient contact with a piece of equipment, including metal parts of the chair, could cause a burn. It is acceptable, however, to permanently attach a metallic mesh grounding antenna to the chain under the upholstery and insultated from all metal chain parts. This can do much to reduce patient anxiety.
The safe use of electrosurgery dictates that current flow be facilitated along the proper circuit from the generator to the active electrode, the patient, and back to the generator. Because patient burns have been attributed to faulty grounding in many cases, the proper grounding of a patient is considered to be the single most important safety factor when electrosurgery is used.
Oringer recommends that the ground be placed under the thigh rather than behind the back, as is often done. Contact with a small, bony protuberance, such a vertebra or shoulder blade, could produce a high enough current density to cause a burn. The only precaution to be observed in placing the ground under the legs is that the patient doesn not have keys in a pants pocket or is not wearing metal garters ( the latter is unlikely in this day).
Contraindications:
For reasons of safety, electrosurgery should not be used in some circumstances. It should not be employed on patients with cardiac pacemakers. The demand (synchronous) type of pacemaker, which is the most common, is designed to sense cardiac impulses ( the R wave). When
bradycardia occurs because the heart does not emit an impulse, the pacemaker fires at an appropriate rate to keep the heart beating. External electromagnetic interference hinders the pacemaker’s sensing function. Incorrectly sensing the interference as an intrinsic myocardial impulse, the generator shuts down until the interference ceases, with consequences that could be quite serious for the patient.
Electrosurgery will alter the normal function of a pacemaker, an it presents a hazard to the patient who wars one. Shielding in recent pacemaker models diminishes the risks from extraneous electromagnetic interferences, but the use of electrosurgery is still contraindicated for those patients who wear pacemakers.
Because it can produce sparks in use, electrosurgery should not be used in the presence of flammable agents. This does not present the risk in dentistry that it does in medicine, because flammable gases are not routinely employed as dental anesthetics such as ethylchloride and other flammable aerosols should be avoided when electrosurgery is to be used.
Many fires in hospital operating rooms do not involve flammable anesthetics. Instead they occur when ordinary combustible materials are ignited in an oxygenated atmosphere that will support a fire. There is a slight danger attached to the use of nitrous oxide with electrosurgery because of the enriched oxygen atmosphere that will be present in the oral cavity and nasopharynx. The number of reported cases involving flash fires caused by dental electrosurgery in the presence of nitrous oxide-oxygen analgesia is minimal. Oringer describes two such occurances. Given the right circumstances with an extremely dry mouth and an accumulation of oxygen, a small spark caused by the electrode touching a metallic restoration could conceivably set off a dry cotton packing. Therefore, whenever electrosurgery is used in the presence of nitrous oxide-oxygen analgesia, be sure that any cotton packing in the mouth is kept slightly moist, if in fact it is not already that way from absorption of oral fluids.
Electrosurgery Armamentarium 1. Electrosurgery unit 2. Set of cutting electrodes 3. Cotton pliers
4. Mouth mirror
5. Fischer Ultrapak Packer
6. DE plastic filling instrument
7. High-volume vaccum with plastic tip 8. Wooden tongue depressor
9. Cotton rolls
10. Cotton-tipped applicator 11. Aromatic oil
12. Hydrogen peroxide 13. Dappen dish 14. Alcohol sponges 15. Retraction cord Electrosurgery technique:
Before an electro surgical procedure is done, verify that anesthesia is profound and reinforce it if necessary. With a cotton-tipped applicator, place a drop of a pleasant smelling aromatic oil, such as peppermint, at the vermillion border of the upper lip. The odor from it will help to mask some of the unpleasant odor emanating from the mouth during electrodurgery.
Check the equipment to make sure all the connections are solid. Be especially certain that the cutting electrode is seated completely in the handpiece. If any uninsulated portion of it other than the cutting tip is an accidental burn on the patient’s lip.
Proper use of electrosurgery requires that the cutting electrode be applied with very light pressure and quick, deft strokes. The pressure required has been described as the same needed to draw a line with an ink-dipped brush without bending the bristles. It is obvious that the electrode is being guided, and not pushed, through the tissue.
To prevent lateral penetration of heat into the tissues with subsequent injury, the electrode should move at a speed of no lessthan 7 mm per second. If it is necessary to retrace the path of a previous cut, 8 to 10 seconds should be allowed to elapse before repeating the stroke. This will minimize the buildup of lateral heat that could disrupt normal healing.
Initially set the power selector dial at the level recommended by the manufacturer and make adjustments as necessary. As the electrode passes through the tissue, it should do so smoothly without dragging or charring the tissue. If the tip drags and collects shreds of clinging tissue, the unit
has been placed on a setting that is too low. On the other hand, if the tissue chars or discolors, or it there is parking, the setting is too high. If an error must be made initially, it is better to have a setting that is slightly too high. Moist tissue will cut best. If it dries out, spray it lightly. Avoid collections of water, however, because that will increase resistance and decrease efficiency.
A high –volume vaccum tip should be kept immediately adjacent to the cutting electrode at all times to draw off the unpleasant odors that are generated. The lip must be plastic to prevent any burns that might be caused by accidental contact with the electrode. For the same reason, a wooden tongue depressor or plastic-handled mirror should be used rather than the metal-backed mouth mirror that would customarily be employed.
Stop frequently to clean any fragments of tissue from the electrode by wiping it with an alcohol-soaked 4x4 sponge. The electrode is completely safe as soon as the foot switch has been released. Proper technique with the cutting electrode can be summed up in three points.
1. Proper power setting
2. Quick passes with the electrode
3. Adequate time intervals between strokes Gingival Sulcus Enlargement
Before any tissue is removed, it is important to assess the width of the band of attached gingiva. The electrosurgery tip is a surgical instrument; it cannot restore lost gingiva. If there is unattached alveolar mucosa too near the gingival crest, peridodontal surgery, probably in the form of a gingival graft, must be employed to reinstate an adequate bend of healthy, attached tissue.
To enlarge the gingival sulcus for impression making, a small, straight or J-shaped electrode is selected. It is used with the wire parallel with the long axis of the tooth so that tissue is removed from the inner wall of the sulcus. If the electrode is maintained in this direction, the loss of gingival height will be about 0.1 mm. Holding the electrode at an angle to the tooth, however, is likely to result in a loss of gingival height.
Around those teeth where the attached gingival tissue is thin and stretched tightly over the bone on the labial surface, there is a greater chance for a loss of gingival height. This is frequently true of maxillary anterior teeth, and particularly the canines, and is worth bearing in mind if the esthetic requirements are great and any gingival recession will be unacceptable.
With the electrosurgery unit off, the electrode is held over the tooth to be operated and the cutting strokes are traced over the tissue. Depress the foot switch before contacting the tissue, and then move the electrode through the first pass. A whole tooth should be encompassed in four separate motions: facial, mesial, lingual and distal at a speed of no less than 7 mm per second one area. Wait 8 to 10 seconds before repeating that stroke. This will minimize the production of lateral heat. Clean tissue debris off the electrode tip after each stroke. Use a cotton pellet dipped in hydrogen peroxide to clean debris from the sulcus. Better results are usually obtained if retraction cord is loosely packed in the enlarged sulcus before the impression is made.
Dental electrosurgery can provide a safe and efficient modality for crating a space in the gingival sulcus by the removal of a small wedge of tissue with an electrode tip. This tissue dilation method is commonly referred to as creating a sub gingival tissue through or subgingival impression funnel. The procedure creates a wedge or soft –tissue funnel that extends from the tissue crest to approximately 0.3 to 0.5 mm below the finish margin. This provides space for an adequate bulk of the elastic impression material beneath the margin and results in more accurate duplication of the preparation for fabricating master casts and dies. The tooth margin is prepared to the gingival crest, the soft tissue funnel is established, and then the margin is refined to the desired sulcular depth.
Caution must be exercised in preparing the margin to the base of the tissue funnel since the impression material will not duplicate tooth structure beneath the finishing line.
When electrosurgery is satisfactorily utilized the tissue response is excellent. Research has established the need for biterminal electrode application and has shown that thehear produced because of tissue resistance disperses in a lateral direction. A fully rectified surgical current produces the least amount of tissue heat and allows for healing by primary intention. A thin layer of coagulum also provides a clot for haling. Bleeding is either non-existent or minimal in the majority of patients.
In the authors opinion, dental electrosurgery provides the following advantages when compared with the other two methods: (1) excellent vision of the margins; (2) refinement of margins to the desired depth in the sulcus after tissue dilation; (3) access to root caries by rapid tissue removal; (4) hemostasis; (5) predictable healing of the tissues; (6) improved accuracy for impression materials by providing increased bulk; (7) reduction in chair time and stress for the patient and the dentist; (8) better access to margins for construction of treatment restorations; (9) ability to remove irregular or excess tissue around the teeth and recontour the pontic space just prior to making impressions; and (10) minimal postoperative discomfort for the patient.
INSTRUMENTATION
The electronic current of choice for tissue displacement is the surgical current. The coagulation current should only be used for bleeding control. Small single or thin double wire loop electrodes are suggested to expose the margins. Electrode is commonly used for anterior teeth and the single or double wire loop for posterior teeth (Fig.2, A and B). For the neophyte, the J loop or A.P. 11/2 electrode (Fig.2c) can provide guidance in establishing the depth of the subgingival tissue trough. The short end of the J loop electrode is 1.5 subgingival tissue trough. The short end of the J loop electrode is 1.5 mm and the exposed portion of the A.P. 1 ½ electrode is the same length. The depth can then be controlled by the amount of the electrode visible above the tissue crest. As an example, for a 0.75 mm trough depth, 0.75 mm of the J loop or A.P. 1 ½ electrode would be above the gingival crest as trough is established. The short side of the J loop is furthest from the tooth. A disadvantage of the J loop is cleaning the shortside of the electrode between application. The cleaning the shortside of the electrode between applications. The short end catches in the 2”X2”
gauze pads used to clean the electrode.
Additionally, small loop electrodes are used in removing redundant tissue approximating the teeth or in the pontic area (Fig.3). Whether the dentist is restoring several single teeth or placing a fixed partial denture, the tissue should be recontoured to provide the treatment indicated for the individual patient.
ANTERIOR RESTRORATIONS
Exposure of the preparation margin for single or multiple individual restorations on the anterior teeth is most exacting. The tissue is thinner at the gingival crest than at the posterior teeth, with the possible exception of the mandibular first premolars. Regardless of the tissue dilation method used, great care must be exercised during the procedure. Figure 1 illustrates the type of gingival tissue that yields predictable results when using tissue dilation procedures. For the maxillary and mandibular central and lateral incisors a single wire tip electrode is suggested. The tooth
Exposure of the preparation margin for single or multiple individual restorations on the anterior teeth is most exacting. The tissue is thinner at the gingival crest than at the posterior teeth, with the possible exception of the mandibular first premolars. Regardless of the tissue dilation method used, great care must be exercised during the procedure. Figure 1 illustrates the type of gingival tissue that yields predictable results when using tissue dilation procedures. For the maxillary and mandibular central and lateral incisors a single wire tip electrode is suggested. The tooth