Category Archives: Principles of Management of Impacted Teeth

PERIOPERATIVE PATIENT MANAGEMENT

The removal of Impacted third molars is a surgical procedure that is associated with a large amount ‘of patient  anxiety. In .addition, this surgical procedure can involve-unpleasant noises and sensations. As a result, surgeons who routinely perform surgical removal of impacted
third molars com monly recommend to their patientssome type of profound anxiety control such as a general anesthetic or deep intravenous (IV) sedation. The choice of technique is based on the surgeon’s preference.
However, the  goals are to achieve a level ofpatient comfort that allows the surgeon to work efficiently  and that limits the patient’s experience to the
minimal number of unpleasant effects. Whether a deep IV sedative or a Iight general anesthetic is used, most surgeons intend their patients to have little, if any, unpleasant memory of the surgical experience. In addi-tion to the increased need for anxiety control, a variety of medications are required to control the sequelae of third molar extraction surge~y. The’ use of longacting  local anesthetics should be considered in themandible. They will provide the patient with a pain-free period of 4 to 6 hours during which prescriptions can be. filled and analgesics taken. The surgeon should consider ‘writing a prescription for a potent oral analgesic for every
patient w ho undergoes surgical removal ofarr impactedthird molar. Enough tablets should be prescribed to last for 3 or 4 days. Combinations of codeine or codeine congeners with aspirin or acetaminophen are commonly used. Nonsteroidal antiinflammatory drugs (NSAf[)s)
may be of some value for certain patients.To minimize the swelling common after the  removal of impacted third molars, some  to give parenteral steroids. amount of a glucocorticoid steroid provides sufficient antunrlammatory activity to give relief to swelling.
Although many different regimens and protocols for steroids exist, a relatively common one is the single administration 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 ster ids given in this manner have few side effects or contraindicatlons, the general philosophy  of weighing the risks and benefits of drug administration must be carefully followed before the decision is made to give these dru gs routinely. .Many surgeons recommend the use of ice packs on the face to help prevent postoperative swelling. Although it is
unlikely that the  ice has much effect on preventingswelling, patients ‘frequently report that the ice made them feel more comfortable. Something cool applied to . the face often makes patients more comfortable. It also
provides them  the opportunity to participate in theirpostoperative care, which is important for many patients. The intraoral use of ice may have additional benefit. Gently sucking on small pieces of ice or even on commerciai  Popsicles may be of some value in helping patients feel more  comfortable, although any measurable decrease in swelling in patients who use this technique is unlikely. Another medication that is sometimes used is an antibiotic.  If a patient has had a preexisting pericoronitis, it iscommon to prescribe antibiotics for a few days after surgery. However, if the patient is healthy and the clinician finds no systemic indication for antibiotics. or a preexisting  local infection, antibiotics are usually not indicated.The normal postoperative experience of a patient after  surgical. removal of an impacted’ third molar is more involved than after a routine extraction. The patient can expect a modest amount of swelling in the area of the surgery
for 3 to 4 days, with the swelling completely dissipatingby about 5 to 7 days. A modest amount of discomfort usually follows the procedure. This discomfort can be effectively controlled with potent oral analgesics.
Patients us ually require analgesics for 2 or 3 days on a routlne basis and intermittently for several more days. The patient may have some mild soreness in the 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 to open the mouth interferes with the
patient’s normal or al hygiene and eating habits. Patients should be warned that they will be unable to open their mouths normally after surgery. The trismus gradually resolves, and the ability to open the mouth should return
to normal by 10 to 14 days after surgery.  All of the sequelae of the surglcal removal of impacted teeth are of less intensity in the young, healthy patient
and of far greater intensity in the older, more debilitated patient. Even healthy adult patients between the ages of  to 40 years have a significantly more difficult time after the extraction of impacted ‘third molars than do
healthy 17-year-ol d pattents. See Chapter 10 for a more detalled  escription of postoperative  care

SURGICAL PROCEDURE

The principles andsteps for removing impacted teeth are the same as for other surgical extractions. Five basic steps make up the technique: The first’ step is to have adequate exposure of the area of the impacted tooth. This means that the reflected soft tissue flap must be of an adequate dimension to allow the surgeon to retract the soft tissue and perform the necessary surgery. The second step is to assess the need for bone removal and to remove a sufficient amount of bone to expose the tooth for sectioning
and delivery.  The third step is to divide the tooth with abur or chisel to allow the tooth to be extracted without removing excessive amounts of bone. In the fourth step the sectioned tooth is delivered from the alveolar process  with the appropriate elevators. Finally, in the fifth step the.wound is thoroughly cleansed with irrigation and mechanical debridement with a curette and is closed with simple   interrupted sutures. The following discussion elaborates onthese steps for the removal of impacted third molars. Although the surgical approach to. the removal of impacted teeth is similar to other surgical tooth extrac tions, it is important to keep in mind several distinct differences. For instance, the typical surgical extraction of a
tooth or tooth root requires  the removal of a relativelysmall 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 substantially greater. .This bone is also much’denser than it is’ for typical surgical extractions, and its  removal requires better  nstrumentation and a higherdegree of surgical skill Impacted teeth also frequently require sectioning, whereas other types of tooth, extractions do not. Although ‘erupted maxillary and mandibular molars are  occasionally divided for removal, it is not a routine stepin the extraction of these teeth. However, with impacted mandibular third molars, tile surgeon is required to divide the tooth in a substantial majority of patients. The  surgeon must therefore have the necessary equipment for – ‘such sectioning and the necessary skills and experience for dividing the tooth along the proper planes.  Unlike most other types of surgical tooth extractions,for an impacted tooth removal the surgeon must be able to balance the degree of bone removal and sectioning. Essen

DIFFICULTY OF REMOVAL OF OTHER  IMPACTED TEETH

most commonly impacted tooth is the maxillary canine. If  the patient seeks orthodontic care, the orthodontist will frequently request that the maxillary canine simply have the overlying soft and hard tissue removed so that the  tooth can be manipulated into its proper position byorthodontic appliances. When the tooth is positioned in such a way that orthodontic manipulation can assist the proper positioning of the impacted canine, the tooth is exposed and bracketed (Fig. 9-42, A). A four-corner flap is
created  to allow the soft tissue to be repositioned apically should this be required for maximum keratinized tissue rnuiagement t+Ig. 9-42, B). The overlying bone tissue is then removed with chisel or burs as is-necessary (Fig. 9-42, 0. Once the area is debrided, the surface of the tooth is prepared by the usual standard procedures of etching and applying primer. The bracket is then luted to the surface of thetooth (Fig. 9-42, D). A wire Call be used to connect the bracket to the orthodontic appliance or more commonly a gold chain is attached from the orthodontic bracket to the
orthodontic arch wire. The gold chain provides a greater  degree of flexibility and -the incidence of breakage of thechain ts much less than breakage of a wire. Fhe soh tissue   is then sutured ill such a \\’ay as to provide, the maximum•coverage 01 the exposed tissue with keratinized tissue (fig. 9-42, 1:). A~the tooth is pulled into place with the ortho-,
dontic app liances, the soft tissue surrounding the newlypositioned tooth should have adequate keratinized tissue and the tooth should be in an ideal position.  If the tooth is positioned ‘toward the palatal aspect, the tooth may be either repositioned or removed. f the toothis repositioned, it is surgically exposed and moved into position orthodontically. In this procedure the overlying  is excised; flaps are not needed to gain attached
tissue. Because the bone  in the ‘palate is thicker, a bur isusually necessary to remove the overlying bone. The exposed tooth then is managed in the same manner as is the labially positioned tooth. ‘ If the dentist decides the tooth should be removed, it must be determined if the tooth is positioned labially.toward the palate, or in the middle of the alveolar process. If the t ooth is on the-‘labial aspect, It is easy to reflect a soft tissue flap and to remove the underlying bone and the tooth. However, if the tooth is on the
palatal aspect or in the intermediate buccoiingual position, it is much more difficult to remove. Therefore when assessing the impacted maxillary canine for removalsurgeon’s most important assessment is 01 the buccolin- .gual position of the tooth.   Similar considerations are necessary for other irnpactions, such as mandibular premolars and supernumerary
teeth. The super  tooth in the midline of the  maxilla, called a mesiodens, is almost always found on the palate and should be approached from a palatal direction when it is removed.

MODIFICATION OF CLASSI FICATION SYSTEMS FOR MAXILLARY IMPACTED TEETH

The classification systems for the maxillary impacted third molar are essentially the same as for the impacted  mandibular third molar, However, several distinctionsand additions must be made to assess more accurately the  difficulty of removal during the treatment-planningphase of the  procedure. oncerning, angulation, the three types of maxillary third molars are (1) the vertical impaction (Fig. 9-39, A), (2) the distoangular impaction (Fig. 9-39, B), and (3) the mesioangular impaction (Fig. 9-39, C). The vertical impaction OCCUrsapproximately 63O,{) of the time, the distoangular approximately 25%, and the mesioangular position appr oximately ]2% of the time. Rarely other positions, such as a transverse, inverted, or horizontal position,  are encountered; these. unusual positions account for less  than 1’X, of impacted maxillary third molars., The same angulations in mandibular third molar extractions cause opposite degrees of difficulty for maxillary third molar extractions. Vertical and distoangular
impactions are the easiest to remove   mesioangularimpactions are the most difficult (exactly the opposite of impacted mandibular third molars). Mesioangular impactions are more difficult to remove because the bone
that overlies t he impaction and that must be removed orexpanded is on the posterior aspect of the tooth and is much heavier than in the vertical or distoangular impaction. In addition, access to the mcsloangularly   ositionedtooth is more difficult.  The position of the maxillary third molar in a buccopalataldirection is also important for deter.ninu ,g the difficulty
of the removal. Most maxillary third molars areangled toward the buccal aspect of the alveolar process, which makes the “overlying bone in thai area thin and therefore easy to remove or to expand. Occasionally, the -impac ted maxillary third molar is positioned toward the  palatal aspect of the alveolar process, This makes the too.th much more difficult to extract, because greater amounts of bone must be removed to gain access to the underlying tooth. A combination of radlographic assessment and clinical
digital palpation of the tuberosity area can determine if the maxillary third molar is in the buccopalatal position.  If the tooth is positioned toward the buccal, a definite palpablebulge is found in the area; if the tooth is palatally
.positloned, a bony deficit is found in t hat region. Wheneither is determined by clinical examination, the surgeon must anticipate a longer, more difficult procedure. The Pel! and Gregory A, B, and C classification used to diagnose the depth of impaction in the mandible is also used in the maxilla (Fig. 9-40). Preoperative assessment of the remaining classifications is the same. The.factors that influence the difficulty of mandibular impacted third molar removal are the same for maxillary third molar removal. For example, the individual impacted tooth root
morph ology plays a substantial role in determining thedegree of extraction difficulty. The most common factor that causes difficulty with maxillary third molar removal  is a thin, non fused root with erratic curvature (Fig. 9-41).The majority of m axillary third molars have fused roots that are conic. However, the surgeon should examine thepreoperative radiograph carefully to ensure that .this is the situation with each individual impaction. The surgeon should also check the periodontal ligament, because
the wider the ligament space the-less difficult the tooth isto remove,’ In addition, similar to mandibular third .molars, the periodontal ligament space tends to decrease as the patient increases in age,  The follicle surrounding the crown of the impacted tooth also has an influence on th-e difficulty of the   extraction. “Ifthe follicular space is broad, the tooth will
be easier to remove than if the follicular space is thin or nonexistent.
BORe density is also an important factor in maxillary impaction removal and is related closely to the age of the  patient. The younger the patient, the less dense and more elastic-and therefore more expandable-is the h(lr.~·sur
rounding the impact ed third molar. As the pat« nt ages,the bone becomes denser and less elastic, and the tooth  becomes more difficult to remove.palatal aspect of the alveolar  process, This makes the tooth much more difficult to extract, because greater amounts of bone must be  removed to gain access to the underlyingtooth. A combination of radlographic assessment and clinical  digital palpation of the tuberosity area can determine  if the maxillary third molar is in the buccopalatal position.If the tooth is positioned toward the buccal, a definite palpable
bulge is found in the  area; if the tooth is palatally.positloned, a bony deficit is found in that region. When  either is determined by clinical examination, the surgeon  must anticipate a longer, more difficult procedure.The Pel! and Gregory A, B, and C classification used to diagnose the depth of impaction in the mandible is also  used in the maxilla (Fig. 9-40). Preoperative assessment of the remaining classifications is the same. The.factors that
influence the d ifficulty of mandibular impacted third molar removal are the same for maxillary third molar removal. For example, the individual impacted tooth root morphology plays a substantial role in determining the
degree of extraction  difficulty. The most common factor that causes difficulty with maxillary third molar removal is a thin, non fused root with   curvature (Fig. 9-41).  The majority of maxillary third molars have fused roots that are conic. However, the surgeon should examine thepreoperative radiograph carefully to ensure that .this is
the  situation with each individual impaction. The surgeonshould also check the periodontal ligament, because  the wider the ligament space the-less difficult the tooth isto remove,’ In addition, similar to mandibular third
.molars, the periodont al ligament space tends to decreaseas the patient increases in age, . The follicle surrounding the cron of the impacted
tooth also has an i fluence on th-e difficulty of the  extraction. “Ifthe follicular space is broad, the tooth will be easier to remove than if the follicular space is thin or nonexistent. BORe density is also an important factor in maxillary impaction removal and is related closely to the age of the  patient. The younger the patient, the less dense and more elastic-and therefore more expandable-is the h(lr.~·surrounding the impacted third molar. As the pat« nt ages, the bone becomes denser and less elastic, and the tooth becomes more difficult to remove.

Nature of Overlying Tissue

The preceding-systems all classify factors that make third molar extraction easier or more difficult. The classification  system discussed in this section does not fit into this category. However, it is the system used by most dental
insurance ‘companies and the one by which the surgeon charges for his

 

 

According to this scheme, the three types of impactions  are (1) soft tissue impaction, (2) partial bony impaction, and (3) full bony impaction. An impaction is defined as a soft tissue impaction when the height of the tooth’s contour is above the level of the alveolar. bone, and the superficial portion of the tooth is covered only by soft. tissue (Fig. 9-36). To remove the soft tissue  impaction, the surgeon must incise the soft tissue andreflect a small soft tissue flap to obtain access to the tooth to elevate it from its socket. The soft tissue impaction is  usually the easiest of the three extractions.The partial bone impaction occurs when the superficial portion of the tooth is covered by soft tissue, but the  height of the tooth’s contour is below the level of the surroundingalveolar bone (Fig. 9-37). To remove the tooth,
the surgeon must incise the sof t tissue, reflect a soft tissueflap, and remove the bone above the height of the’ contour. The surgeon may need to divide the tooth in addtion  to removing bone.The complete bone tmpactton is an impacted tooth  that is completely encased in bone so that, when the surgeon  reflects the soft tissue trap, no tooth is visible (Fig.9-38). To remove the tooth, extensive amounts of bone must be removed and the tooth almost always must be sectioned. The complete bony impaction is often the most difficult to remove. Although this classification is extensively used, it frequently has no relationship to the difficulty of the extraction  (Boxes 9-1 and 9-2). The parameters of angulation,

BOX 9_1

Factors that MakeImpaction Surgery Less Difficult

1. Mesioangular
position
2. Class 1 ramus
3. Class A depth
4. Roots one third to
two thirds formed”
5.1=used conic roots
6. Wide periodontal
ligament”
7. Large follicle”
8. Elastic bone”
, 9¥ Separated from second
‘molar ‘
10. Separated from. inferior
alveolar nerve”
11. Soft tissue impaction

BOX 9-2

Factors that Make Impaction Surgery More Difficult
1. Distoanqular
2. Class 3 ramus
3. Class C depth
4. Long, thin roots”
5. Divergent curved
roots
6: Narrow periodontal
ligament”
7. Thin follicle”
8. Dense, inelastic bone”
9. Contact with second
molar
10. Close to inferior alveolar
canal
11. Complete bony impaction
“Present in older patients.

Relationship to Inferior Alveolar Nerve

Impacted mandibular third molars frequently have roots that are superimposed on the inferior alveolar canal on radiographs. Although the canal is usually on the buccal  aspect of the tooth, it is in close proximity to the tooth. Therefore one of the potential sequelae of impacted thirdmolar removal is damage to or bruising of the inferior alveolar nerve. This usually results in some altered sensation (paresthesia or anesthesia) of the lower lip on the  injured side. Although this altered sensation is usuallybrief (lasting only a few days), it may extend for weeks or  months; on rare occasions it can be permanent. If the root ends of the tooth appear to e close to the inferior
alveolar nerve, the s urgeon must take special care to  avoid injuring the nerve Fig. 9-35), which makes the procedure more difficult.

Contact with Mandibular Second Molar

If space exists between the second molar and the impacted third molar, the extraction will be easier, However, if the  tooth is a mesioangular or horizontal impaction, it is frequently in direct contact with the adjacent second molar. To
remove the third molar sa fely without injuring the second• molar, the surgeon must be cautious with pressure from elevators or with the bur when removing bone. If the second molar has caries or a large restoration or root canal, the surgeon must take special care not to fracture the restoration or
a portion of the carious crown (see Fig. 9-17, B)

Density of Surrounding Bone

The density of the bone surrounding the tooth plays a role in determining the difficulty of the extraction.  Although some clues can be seen on the radiographs,variations in radiograph density and angulation  render interpretations based on radio graphs unreliable. Bone densityis best

who are 18 years of age or younger have bone densities  favorable for tooth removal. The bone is less dense, is more likely to be pliable, and expands and bends somewhat,which allows the socket to-be expanded by elevators
or by luxation forces applied to the tooth itself. Addltionally, the bone is easier to cut with a dental drill and can be removed more rapidly than denser bone. Conversely, patients who are older than age 35 have denser bone and thus decreased flexibility and ability to expand. In these patients the surgeon must remove all interfering bone, because it is not possible to expand the bony socket. In addition, as the bone increases in density,it becomes more difficult to remove with a dental drill,  a nd the bone removal process takes longer.

 

 

 

Size of Follicular Sac

The size of the follicle around the impacted tooth can help determine the difficulty of the extraction. If the follicular sac is wide (almost cystic in size), much less bone must be removed, which makes the tooth easier to extract
(Fig. 9-34). (Yo ung patients are more likely to have. large follicles, which  is another factor that makes extractions easier in younger patients.) However, if the follicular space around the crown of the tooth is narrow or nonexistent,
the surgeon m ust create space around the entire crown, which increases both the difficulty of the procedure and the time required to remove the tooth. The surgeon must carefully examine the follicle size when determining the difficulty of an extraction.

ROOT MORPHOLOG Y

.’Just as the root morphology of the erupted tooth has a major influence on the degree of difficulty of a closed extraction, root morphology plays a major role in determining the degree of difficulty of the impacted tooth’s removaL Several factors must be considered when assessing the morphologic structure of the root The first consideration is the length of the root. As discussed earlier, the optimal time for removal of an impacted tooth is when the root is one third to two thirds formed. When this is the case, the ends of the roots are . blunt and almost never fracture (Ffg. 9-29). If the tooth is not removed during the formative stage and the entire length of the root develops, the possibility increa~es for

FIG. 9-29 Roots that are two thirds formed, which are less difficult· to remove abnormal root morphology and for- fracture of the root tips during extraction. If the root development is insufficient (i.e., less than one third complete), the tooth is more difficult to remove; because it tends to roll in its crypt like a bait in a socket, which prevents easy elevation (Fig. 9-30). The next factor to be assessed is whether the roots are fused into a single, conic root (Fig. 9-,31), or if they are separate and distinct roots. The fused, conic roots are eas- . ier to remove than widely separateroots (Fig. 9-32). . The curvature of the tooth roots also plays a role in the difficulty of the  xtraction. Severely curved or dilacerated roots are more.difficult to  emove than straight or slightly curved roots (see Fig. 9-32). The surgeon should carefully examine the apex area of the radiograph to assess 

FIG, 9-30

FIG, 9-30 Lack of root development If extraction is attempted,
crown will roll around if}crypt, which makes it difficult to remove

FIG. 9-31 Fused roots with conic shape.

the presence of ‘small, abnormal, and sharplj’ hooked
roots that probably fracture if the surgeon does not giYC’
them special consideration.
The direction of the tooth root curvature is also important
to examine preoperatively. During removal of a
mestoangirlar impaction, roots that are curved gently in the
distal direction (following along the pathway of extraction)
can be removed without the force that can cause fracture of
the roots. However, if the roots of a mesioangular
tmpacuen are curved mesially, ‘the roots almost always fracture
or must be sectioned before the tooth can be delivered.
The total width of -the·roots in the mesiodistal direction
should be compared with the width of the tooth at the
cervical line. If the tooth root width is greater, the extrac-

FIG. 9-33 Wide periodontal ligament space. Such space makes extraction process less difficult

tion will be more difficult. More bone must be removed or the tooth ‘must be sectioned before extraction. Finally, the surgeon should assess the pcriodontalligament space. Although in: most patients the periodontal
ligament space is of n ormal dimensions, it sometirrres iswider or narrower. The wider the periodontal ligament  space, the easier the tooth is to remove (Fig. 9-33). A third polar that is in the proper stage of development for
removal has a relatively broad periodontal ligament space, which eases’ extraction. However, older patients,  especially those over age 40, tend -to have a much  rower periodontal ltgament space, which thereby lncreases
the difficulty  of the extractionthe presence of ‘small, abnormal, and sharplj’ hooked  roots that probably fracture if the surgeon does not giYC’
them sp ecial consideration.The direction of the tooth root curvature is also important  to examine preoperatively. During removal of amestoangirlar impaction, roots that are curved gently in the distal direction (following along the pathway of extraction) can be removed without the force that can cause fracture of  the roots. However, if the roots of a  esioangulartmpacuen are curved mesially, ‘the roots almost always fracture or must be sectioned before the tooth can be delivered. The total width of -the·roots in the  direction should be compared with the width of the tooth at the cervical line. If the tooth root width is greater, the extract

tion will be more difficult. More bone must be removed or the tooth ‘must be sectioned before extraction. Finally, the surgeon should assess the pcriod on talligament space. Although in: most patients the periodontal
ligament space is of normal dimensions, it sometirrres iswider or narrower. The wider the periodontal ligament space, the easier the tooth is to remove (Fig. 9-33). A third’ molar that is in the proper stage of development for
removal has a relati vely broad periodontal ligamentspace, which eases’ extraction. However, older patients,  especially those over age 40, tend -to have a much narrow rower periodontal ltgament space, which thereby ncreases the difficulty of the extraction.