surgical_procedure

7/30/2019 SURGICAL_PROCEDURE

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SURGICAL PROCEDURE

The principles and steps for removing impacted teeth are thesame as for other surgical extractions. Five basic steps make up thetechnique. The first step is to have adequate exposure of the area of

the impacted tooth. This means that the reflected soft tissue flapmust be of an adequate dimension to allow the surgeon to retractthe soft tissue and perform the necessary surgery. The second stepis to assess the need for bone removal and to remove a sufficientamount of bone to expose the tooth for sectioning and delivery. Thethird step is to divide the tooth with a bur or chisel to allow the toothto be extracted without removing excessive amounts of bone. In thefourth step, the sectioned tooth is delivered from the alveolarprocess with the appropriate elevators. Finally, the wound isthoroughly cleansed with irrigation and mechanical debridementwith a curette and is closed with simple interrupted sutures. Thefollowing discussion elaborates on these steps for the removal of impacted third molars.

While the surgical approach to the removal of impacted teethis similar to other surgical tooth extractions, it is important to keepin mind several distinct differences. For instance, the typical surgicalextraction of a tooth or tooth root requires the removal of arelatively small amount of bone. However, when an impacted tooth(especially a mandibular third molar) is extracted, the amount of bone that must be removed to deliver the tooth is substantiallygreater. This bone also is much denser than it is for typical surgical

extraction, and its removal requires better instrumentation and ahigher degree of surgical skill.

Impacted teeth also frequently require sectioning, whereasother types of tooth extractions do not. Although erupted maxillaryand mandibular molars occasionally are divided for removal, it is nota routine step in the extraction of these teeth. However, withimpacted mandibular third molars, the surgeon is required to dividethe tooth in a substantial majority of patients. The surgeon musttherefore have the necessary equipment for such sectioning, as wellas the necessary skills and experience for dividing the tooth alongthe proper planes.

Unlike most other types of surgical tooth extractions, for animpacted tooth removal the surgeon must be able to balance thedegree of bone removal and sectioning. Essentially, all impactedteeth can be removed without section-ing if a large amount of boneis removed. But the removal of excessive amounts of boneunnecessarily prolongs the healing period and may result in aweakened jaw. Therefore the surgeon should remove mostmandibular third molars only after sectioning them. On the otherhand, removal of a small amount of bone with multiple divisions of the tooth may cause the tooth sectioning process to take an

excessively long time, prolonging the operation unnecessarily. Thesurgeon must remove an adequate amount of bone and section the



tooth into a reasonable number of pieces both to hasten healing andto minimize the time of the surgical procedure.

Step 1: Reflecting adequate flaps for accessibility . Thedifficulty of removing an impacted tooth depends on itsaccessibility. To gain access to the area and to visualize the

overlying bone that must be removed, the surgeon must reflect anadequate mucoperiosteal flap. The reflection must be of adimension adequate enough to allow the placement andstabilization of retractors and instruments for the removal of bone.

In most situations, the envelope flap is the preferredtechnique. The envelope flap is easier to close and heals better thanthe three-cornered flap. However, if the surgeon requires greateraccess to the more apical areas of the tooth, which might stretchand tear the envelope flap, the surgeon should consider using athree-cornered flap.

The preferred incision for the removal of an impactedmandibular third molar is an envelope incision that extends from themesial papilla of the mandibular first molar, around the necks of theteeth to the distobuccal line angle of the second molar, and thenposteriorly to and laterally up the anterior border of the mandible(Fig. 9-43, A). The incision must not continue posteriorly in a straightline because the mandible diverges laterally, as well as posteriorly.An incision that extends straight posteriorly falls off the bone andinto the sublingual space and may damage the lingual nerve, whichis in close proximity to the mandible in the area of the third molar. If this nerve is traumatized, the patient probably will have a lingual

nerve anesthesia, which may be distracting to the patient. Since theincision must always be on bone, the surgeon should palpate theretromolar area carefully when beginning the incision.

The flap is reflected with laterally to approximately theexternal oblique ridge with a periosteal elevator Fig. (9-43, B). Thesurgeon should not reflect beyond the external oblique ridgebecause this results in increased morbidity and an increasednumber of complications following surgery. The retractor is placedon the buccal shelf just at external oblique ridge and is stabilized byapplying pressure toward the bone. This results in a retractor that isstable and does not continually traumatize the soft tissue. The

Austin and the Minnesota retractors are the most commonly usedfor flap reflection when removing mandibular third molars.

If the impacted third molar is deeply embedded in bone andrequires more extensive bone removal, a releasing incision may beuseful (Fig. 9-43, C and D) . The flap created by this incision can bereflected farther apically without risk of tearing the tissue.

The recommended incision for the maxillary third molar is alsoan envelope incision. It extends posteriorly from the distobuccal lineangle of the second molar and anteriorly to the mesial aspect of thefirst molar (Fig. 9-44, A and B) . In situations in which much access

is required (for instance, in a deeply embedded impaction), arelease incision extending from the mesial aspect of the second



molar can be used (Fig. 9-44, C and D).In the removal of third molars, it is vital that the flap be large

enough for adequate access and visibility of the surgical site. Theflap must have a broad base if the release incision is used. Theincision must be made with a smooth stroke of the scalpel, which is

kept in contact with bone throughout the entire incision so that themucosa and periosteum is completely incised. This allows a full-thickness mucoperiosteal flap to be reflected. The incision should bedesigned so that it can be closed over solid bone (rather than over abony defect). This is achieved by extending the incision at least onetooth anterior to the surgical site when a vertical releasing incisionis used. The incision should avoid vital anatomic structures. Only asingle releasing incision should be used.

Step 2: Removal of overlying bone. Once the soft tissue iselevated and retracted so that the surgical field can be visualized,the surgeon must make a judgment concerning the amount of boneto be removed. In some situations the tooth can be sectioned with achisel and delivered without bone removal. In most cases, however,some bone removal is required.

Although chisels can be used to remove bone overlyingimpacted teeth, most surgeons and patients prefer that bone beremoved with a drill. The preferred instrument is a handpiece withadequate speed, high torque, and the ability to be sterilizedcompletely, usually in a steam autoclave.

The bone on the occlusal aspect and on the buccal and distalaspects down to the cervical line of the impacted tooth should be

removed initially. The amount of bone that needs to be removedvaries with the depth of the impaction, the morphology of the roots,and the angulation of the tooth. Rarely, if ever, is bone removed onthe lingual aspect of the mandible because of the likelihood of damaging the lingual nerve.

The burs that are used to remove the bone overlying theimpacted tooth vary with surgeons' preferences. A large round bur,such as a No. 8, is desirable because it is an end-cutting bur and canbe used effectively for drilling with a pushing motion. The tip of afissure bur, such as a No.703 bur, does not cut well. but the edgeremoves bone rapidly and sections teeth quickly when used in a

lateral direction. The typical bone removal for the extraction of an impacted

mandibular tooth is illustrated in Fig. 9-45. The bone on the occlusalaspect of the tooth is removed first to expose the crown of thetooth. Then the cortical bone on the buccal aspect of the tooth isremoved down to the cervical line. Next, the bur can be used toremove bone between the tooth and the cortical bone in thecancellous area of the bone with a maneuver called ditching. Thisprovides access for elevators to gain purchase points.

For maxillary teeth, bone is removed primarily on the buccal

aspect of the tooth down to the cervical line to expose the entireclinical crown. Additional bone must be removed on the mesial



aspect of the tooth, allowing an elevator an adequate purchasepoint to deliver the tooth. Since the bone overlying maxillary teethis usually thin, it can be removed easily with a unibevel chisel withonly hand pressure.

Step 3: Sectioning the tooth. Once sufficient amounts of bone

have been removed from around the impacted tooth, the surgeonshould assess the need to section the tooth. Sectioning allowsportions of the tooth to be removed separately with elevatorsthrough the opening provided by removal.

The direction in which the impacted tooth should be divided isprimarily dependent on the angulation of the impacted tooth.Although minor modifications are necessary for teeth with divergentroots or for teeth that are more deeply or less deeply impacted, themost important determinant is the tooth's angulation.

Tooth sectioning can be performed with either a bur or chisel;however, the bur is used by most surgeons. If a chisel is used, itmust be extremely sharp and the blows delivered to it by the malletmust be sharp and forceful enough to split the tooth. For theconscious patient, the sound of the chisel striking the tooth may bebothersome.

When the bur is used, the tooth is sectioned three fourths of way toward the lingual aspect. A straight elevator is inserted intothe slot made by the bur and rotated to split the tooth. The burshould not be used to section the tooth completely through in thelingual direction, since this is more likely to injure the lingual nerve.

The mesioangular impaction is usually the least difficult to

remove of the four basic angulation types. After sufficient bone hasbeen removed, the distal half of the crown is sectioned off at thebuccal groove to just below the cervical line on the distal aspect. This portion is delivered. The remainder of the tooth is removed witha No. 301 elevator placed at the mesial aspect of the cervical line. Amesioangular impaction also can be removed by preparing apurchase point in the tooth with the drill and using a Crane pickelevator to elevate the tooth from the socket (Fig. 946).

The next most difficult impaction to remove is the horizontalimpaction. After sufficient bone has been removed down to thecervical line, exposing the superior aspect of the distal root and the

majority of the buccal surface of the crown, the tooth is sectionedby dividing the crown of the tooth from the roots at the cervical line. The crown of the tooth is removed, and the roots are displaced witha Cryer elevator into the space previously occupied by the crown. If the roots of an impacted third molar are divergent, they may needto be sectioned into two separate portions and delivered individually(Fig. 9.47).

The vertical impaction is one of the two most difficultimpactions to remove. The procedure of bone removal andsectioning is similar to the mesioangular impaction; that is, the

occlusal buccal and distal bone is removed. The distal half of thecrown is sectioned and removed, and the tooth is elevated by



applying an elevator at the mesial of the cervical line of the tooth. This is more difficult than a mesioangular removal because accessaround the mandibular second molar is difficult to obtain andrequires the removal of substantially more bone on the buccal anddistal sides (Fig. 9-48).

The most difficult tooth to remove is the distoangularimpaction. After sufficient bone is removed from the buccal-occlusaland the distal sides of the tooth, the crown is sectioned from theroots just above the cervical line. The entire crown is usuallyremoved because it interferes with visibility and access to the rootstructure of the tooth. If the roots are fused, a Cryer or straightelevator can be used to elevate the tooth into the space previouslyoccupied bythe crown. If the roots are divergent, they usually are sectioned intotwo pieces and delivered individually. Extracting this impaction isdifficult because much distal bone must be removed and the toothtends to be elevated distally and into the ramus portion of themandible (Fig. 9-49).

Impacted maxillary teeth rarely are sectioned because theoverlying bone is usually thin and relatively elastic. In situation inwhich the bone is thicker or patient is older (and therefore the bonenot so elastic), tooth extraction is usually accomplished by boneremoval rather than tooth sectioning. Under no circumstancesshould a chisel be used to section maxillary teeth becausedisplacement of the tooth into the maxillary sinus is hightly likely.

In general, impaced teeth elsewhere in the mouth usually are

sectioned only at the cervical line. This permits removal of thecrown portion of the tooth, displacement of the root portion into thespace previously occupied by the crown, and removal of the rootportion.

Step 4: Delivery of the sectioned tooth with elevator . Onceadequate bone has been removed to expose the tooth and the toothhas been sectioned in the appropriate fashion, the tooth is deliveredfrom the alveolar process with dental elevators. In the mandible, themost frequently used elevators are the straight elevator, the pairedCryer elevator , and the Crane pick.

An important difference between the removal of an impacted

mandibular third molar and of a tooth elsewhere in the mouth isthat there is almost no luxation of the tooth for the purpose of expansion of the buccal or lingual cortical plate. Instead, bone isremoved and teeth are sectioned to prepare an unimpeded pathwayfor delivery of the tooth. Application of excessive force may result inunfavorable fracturing of the tooth, of excessive buccal bone, of theadjacent second molar, or possibly of the entire mandible. Elevatorsare designed not to deliver excessive force but to engage the toothor tooth root and to apply force in the proper direction. Some highlyskilled surgeons use the periapical curette to remove sectioned

roots from their sockets. Because the impacted tooth has neversustained occlusal forces, the periodontal ligament is weak,



permitting the easy displacement of the tooth root if appropriatebone is removed and force is delivered in the proper direction.

Delivery of maxillary third molars is accomplished with smallstraight elevators such as the No. 301 elevator, which luxates thetooth distobuccally. Some surgeons prefer angled elevators, such as

the Potts or Miller elevators, which aid in gaining access to theimpacted tooth. The elevator tip is inserted into the area at themesial cervical line, and force is applied to displace the tooth in thedistobuccal direction (Fig. 9-50). The surgeon should be cautiousabout applying excessive pressure anteriorly to avoid damage to theroot of the maxillary second molar. In addition, as pressure isapplied to displace the tooth posteriorly, the surgeon should have afinger on the tuberosity of the maxilla (especially if the impaction ismesioangular), so that if a fracture does occur, steps can be takento salvage the tuberosity of the maxica.

Step 5: Debridement of wound and wound closure. Once theimpacted tooth is removed from the alveolar process, the surgeonmust direct his attention to debriding the wound of all particulatebone chips and debris. The surgeon should irrigate the wound withsterile saline, taking special care to irrigate thoroughly under thereflected soft tissue flap. The periapical curette should be used tomechanically debride both the superior aspect of the socket andthe inferior edge of the reflected soft tissue to remove anyparticulate material that might have accumulated during surgery. The bone file should be used to smooth any sharp, rough edges of bone. A mosquito hemostat can be employed to remove any

remnants of the dental follicle. Once the follicle is grasped, it islifted with a slow, steady pressure and will pull free from thesurrounding hard and soft tissue. A final irrigation and a thoroughinspection should be performed before the wound is closed.

The incision closure usually should be a primary closure. If theflap was well designed and not traumatized during the surgicalprocedure. it will fit closely back into its original position. The initialsuture should be made through the attached tissue on the posterioraspect of the second molar. Additional sutures are placedposteriorly from that position and anteriorly through the papilla onthe mesial side of the second molar. Usually three or four sutures

are necessary to close an envelope incision. If a release incision wasused, attention must be directed to closing that portion of theincision as well.

PERIOPERATIVE PATIENT MANAGEMENT The removal of impacted third molar is a surgical procedure

that is associated with a large amount of patient anxiety. Inaddition, this surgical procedure can involve a number of unpleasantnoises and sensations. As a result, surgeons who routinely performsurgical removal of impacted third molars commonly recommend to

their patients some type of profound anxiety control, such as ageneral anesthetic or deep IV sedation.



The choice of technique is based on the surgeon's preference.However, the goals are to achieve a level of patient comfort thatallows the surgeon to work rapidly and be efficiently and that limitsthe patient's experience to the minimal number of unpleasanteffects. Whether a deep IV sedative or a light general anesthetic is

used, most surgeons intend their patients to have a profoundamnesia of the procedure. Thus the patient has little if anyunpleasant memory of the surgical experience.

In addition to the increased need for pain and anxiety control,a variety of medications are required to control the sequelae of thirdmolar extraction surgery. The surgeon should consider writing aprescription for a potent oral analgesic for every patient whoundergoes surgical removal of an impacted third molar. Enoughtablets should be prescribed to last for 3 or 4 days. Combinations of codeine, or codeine congeners, with aspirin or acetaminophencommonly are used. Nonsteroidal antiinflammatory analgesics maybe of some value for certain patients.

To minimize the swelling common after the surgical removalof impacted third molars, some surgeons prefer to give parenteralsteroids. Intravenous administration of a modest amount of aglucocorticoid steroid provides sufficient antiinflammatory activityto give relief from swelling. Although many different regimens andprotocols of steroids exist, a relatively common one is the singleadministration of 8 mg of dexamethasone before surgery.

This is a relatively long-acting steroid, and its efficacy in

controlling third molar postsurgical swelling is documented.Although steroids given in this manner have few side effects orcontraindications, the general philosophy of weighing the risks andbenefits of drug administration must be followed carefully beforethe decision is made to give these drugs routinely.

Another medication that sometimes is used is an antibiotic. If a patient has had a preexisting pericoronitis, it is common toprescribe antibiotics for a few days after surgery. However, if thepatient is healthy and there is no systemic indication for antibioticsor preexisting local infection, antibiotics usually are not prescribed.

The normal postoperative experience of a patient after

surgical removal of an impacted third molar is more involved thanafter a routine extraction. The patient can expect a modest amountof swelling in the area of the surgery for 3 or 4 days, with theswelling completely dissipating by about 10 days. A modest amountof discomfort usually follows the procedure. This discomfort can beeffectively controlled with potent oral analgesics. Patients usuallyrequire analgesics for 2 or 3 days on routine basis and intermittentlyfor several more days. The patient may have some mild soreness nthe region for 2 to 3 weeks after the surgery.

Patients who have had mandibular third molars surgically

removed frequently have mild to moderate trismus. This inability toopen the mouth interferes with the patient's normal oral hygiene



and eating habits. Patients should be warned that they will beunable to open their mouths normally following surgery. The trismusgradually resolves, and the ability to open the mouth should returnto normal by 10 to 14 days after surgery.

All of the sequelae of the surgical removal of impacted teeth

are of less intensity in the young, healthy patient and of far greaterintensity in the older, more debilitated patient. Even healthy adultpatients between the ages of 35 to 40 years have a significantlymore difficult time following the extraction of impacted third molarsthan do healthy 17-year-old patients.

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