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WOUND HEALING
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Din Lam
CHAPTER 24
1. What are the three phrases of wound healing?
1. Inflammatory phase
2. Proliferative phase
3. Remodeling phase
2. What events occur during each phase of wound healing?
The inflammatory phase begins at the time of wounding and lasts for 24 to 48 hours. At this stage,
platelets release growth factors to attach macrophages and neutrophils to the healing site. The
goal for this stage is to remove debris, necrotic tissue, and bacteria from the wound. By day 3,
the proliferative phase begins, and at this point, fibroblasts start to produce collagen in a random
fashion. This is when the wound starts to gain its initial strength. Moreover, it is also at this stage
that angiogenesis begins at the healing site. At the last stage—the remodeling phase—randomly
aligned collagen will be replaced by organized collagen that provides stronger strength to the site.
This last stage occurs 2 to 3 weeks after wounding and can last for more than a year.
3. What role do macrophages play in wound healing?
Macrophages play a critical role in removing debris and bacteria and, most importantly, secrete
growth factors that promote collagen formation by fibroblasts.
4. What roles do the growth factors PDGF and TGF-β play in wound healing?
Platelet Derived Growth Factor (PDGF) is released by platelets during formation of initial thrombus. It is
a chemoattractant for macrophages, which are responsible for orchestrating events of healing. Transforming Growth Factor-Beta (TGF-β) is secreted by macrophages, is a chemoattractant for fibroblasts,
and stimulates formation of extracellular matrix by fibroblasts.
5. How does the collagen pattern change during wound healing?
During the remodeling phase, fibroblasts and macrophages replace the initial, randomly laid collagen
with collagen that is cross-linked and oriented in a more orderly arrangement to the direction of
mechanical stress. This new pattern of collagen formation is a lot stronger than those found in initial,
randomly laid collagen.
6. A well-healed wound eventually reaches what percentage of pre-wound strength?
In general, well-healed wounds can reach 70% to 80% of prewound strength.
7. Is collagen makeup different in normal versus newly healing wounds?
Type I collagen is the most abundant type of collagen in normal dermis. Type II collagen is the most
abundant collagen during the early phase of wound healing. By week 2 of the wound healing process,
type III collagen becomes the principal collagen produced by fibroblast until at the remodeling phase,
at which type I collagen is replacing type II collagen to restore the normal tissue profile.
8. What effect does radiation have on wound healing?
Radiation causes endothelial cell, capillary, and arteriole damage, which results in progressive and
cumulative loss of blood vessels in the affected area. Perfusion to the radiated tissue may be affected,
leading to delayed healing. Radiated fibroblasts show decreased proliferation and collagen synthesis,
leading to diminished deposition of extracellular matrix. The lymphatic system may also be damaged
and lead to prolonged edema and poor clearance of infection in the healing process.
9. What factors commonly impair wound healing?
Nutritional deficiencies, aging, infection, hypoxia, steroids, smoking, diabetes, and radiation.
10. Why does edema impair wound healing?
In normal tissue, cells are in close proximity to the vessels where oxygen and nutrients are diffused
to the cells. Edema impairs wound healing by (1) increasing the distance between cells and vessels
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that indirectly impair the diffusion process, (2) chronic edema may result in protein deposition in the
extracellular matrix, which can act as a diffusion barrier for growth factors and nutrients, and (3)
growth factors and nutrients are relatively diluted in the edematous fluid.
11. What is the mechanism of wound contraction?
The wound heals by wound contraction, reepithelialization, and scarring. As an integral part of wound
healing, myofibroblasts orient themselves along lines of tension and pull collagen fibers together. Scar
contracture is an abnormal shortening and thickening of a scar that may cause function or cosmetic
deformities.
12. How much bacteria is needed to cause wound infection?
A wound with bacterial counts greater than 105 organisms per gram of tissue is considered infected
and unlikely to heal without further treatment.
13. What factors are responsible for local wound ischemia?
Smoking, radiation, edema, diabetes, and peripheral occlusive disease can affect the perfusion and
oxygenation of a wound and cause local wound ischemia.
14. What are the benefits of occlusive dressings?
Occlusive dressings maintain a moist environment that promotes rapid reepithelization and more
effective wound healing than when the wound is allowed to dry out.
15. What causes hypertrophic/keloid scars? What treatment options are available?
Excessive inflammatory response during healing is most likely the cause of hypertrophic/keloid scars.
No definitive treatment option is available for both. In most cases, multimodal therapies, including
intralesional steroid injection, surgical resection, and occlusive dressing are needed to decrease the
appearance of the hypertrophic/keloid scars.
16. What features distinguish between a keloid and hypertrophic scar?
Keloids usually extend beyond the original incision and become progressively larger. Hypertrophic
scars are elevated but do not extend outside the original borders of the wound. Keloids are more common in people with dark skin, whereas hypertrophic scars occur more often in fair-skinned people.
17. Which layer of a wound repair contributes the most to wound strength?
The dermal layer contributes the most strength in wound healing. Sutures with prolonged tensile
strength should be used to close this layer. Sutures placed in the epidermis that permit fine alignment
of the skin edges should be removed within 5 days.
18. What is the role of immobilization in wound healing?
By immobilizing the wound, tension across the skin edges is eliminated, yielding a more favorable
scar. Immobilization can be achieved by using Steri-Strip and tapes.
19. What influences the permanent appearance of suture marks?
• Length of time that skin suture remains in place
• Tension on the wound edges
• Region of the body
• Presence of infection
• Tendency for hypertrophic scarring or keloid formation
20. How does vacuum-assisted closure help in the wound healing process?
The application of negative pressure in vacuum-assisted closure removes edema fluid from the
wound through suction. This results in increased blood flow to the wound (by causing the blood vessels to dilate) and greater cell proliferation. Another important benefit of fluid removal is the reduction
in bacterial colonization of the wound, which decreases the risk of wound infections. Through these
effects, vacuum-assisted closure enhances the formation of granulation tissue, an important factor in
wound healing and closure.
DENTOALVEOLAR SURGERY AND
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PREPROSTHETIC SURGERY
CHAPTER 25
Dean M. DeLuke, Vincent J. Perciaccante, James A. Giglio
DENTOALVEOLAR SURGERY
1. Why is it necessary to use a bite block when removing mandibular teeth?
To diminish pressure on the contralateral temporomandibular joint (TMJ).
2. Why is distilled water not used for irrigation?
Distilled water is a hypotonic solution and will enter cells down the osmotic gradient, causing cell lysis
and rapid death of bone cells.
3. Why is buccal to lingual movement not efficient when removing mandibular
posterior teeth?
Mandibular bone is too dense and does not expand in a fashion similar to that of the maxillary bone.
4. What anatomic structure can interfere with efficient removal of a maxillary first
molar?
Root of the zygoma.
5. What anatomic layers are penetrated or contacted when performing an inferior
alveolar nerve block?
Mucosa, buccinator muscle, pterygomandibular space, and periosteum.
6. What muscles insert on the pterygomandibular raphe?
The buccinator muscle and the superior pharyngeal constrictor muscle.
7. What two structures form a V-shaped landmark for an inferior alveolar nerve block?
Deep tendon of the temporalis muscle and the superior pharyngeal constrictor.
8. What is the orthodontic indication for removal of an impacted third molar?
To facilitate distal movement of the second molar.
9. What is the “shift rule” (also called Clark’s Rule) as applied to impacted maxillary
cuspids?
This radiographic technique determines the position of the impacted cuspid. A series of periapical
radiographs are made. The film position is kept constant, but the head of the X-ray unit is moved
either anteriorly or posteriorly after each exposure. If the impacted tooth seems to move with the
X-ray head, it is located on the palate. If it moves opposite to the unit head, it will be found on the
buccal. This is also referred to as the SLOB rule: same lingual (palate), opposite buccal.
10. What is the advantage of an apically positioned mucoperiosteal flap for exposure
of a buccally positioned impacted cuspid?
This flap design allows for the impacted tooth to erupt into attached mucosa and minimizes the pos-
sible development of periodontal defects and pocket formation.
11. Where is the inferior alveolar nerve most often located in relation to the roots of a
mandibular third molar?
Buccal to the roots, and slightly apical.
12. The root of which tooth is most often dislodged into the maxillary sinus during an
extraction procedure?
Palatal root of the maxillary first molar.
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13. While trying to remove a root tip of a mandibular third molar, it disappears from
view. Where might it be dislodged?
• Inferioralveolarcanal
• Cancellousbonespace
• Submandibularspace
14. What is the usually recommended sequence for extractions?
Maxillary teeth before mandibular teeth, and posterior teeth before anterior teeth.
15. What complications are associated with the removal of a freestanding, isolated
maxillary molar?
Alveolar process fracture and fracture of the maxillary tuberosity.
16. How do you minimize the chance of dislodging an impacted maxillary third molar
into the infratemporal fossa during its surgical removal?
Develop a full-thickness mucoperiosteal flap, bringing the incision anterior to the second molar (add
a releasing incision if necessary) to improve visualization of the impacted tooth, and place a broad
retractor distal to the molar while elevating it.
17. When performing a surgical removal, should you completely section through a
mandibular molar?
No. The lingual plate is often thin, and complete sectioning may perforate the plate and injure the
lingual nerve.
18. How is bleeding from pulsating nutrient blood vessels controlled following sur-
gery on alveolar bone?
• Burnishbone.
• Crushwithrongeurs.
• Applybonewax.
19. What are some common causes of postoperative bleeding following dental
extractions?
• Failuretosuture
• Failuretoremoveallgranulationtissue
• Reboundbloodvesseldilationfollowinguseoflocalanestheticwithavasoconstrictor
• Torntissue
• Tornsurgicalaps
20. Why is a mucoperiosteal flap designed with a broad base?
To ensure an adequate blood supply to the flap margin.
21. What are the two basic flaps used in dentoalveolar surgery?
1. Full-thicknessmucoperiostealap
2. Split-thickness mucoperiosteal flap
22. What are the two basic types of full-thickness mucoperiosteal flaps?
1. Envelope flap
2. Envelope flap with a releasing component
23. Where are releasing incisions contraindicated?
• Palate
• Throughmuscleattachments
• Lingualsurfaceofthemandible
• Intheregionofthementalforamen
• Canineeminence
24. How do absorbable gelatin sponges (Gelfoam) and oxidized regenerated cellulose
(Surgicel) assist with homeostasis?
They form a matrix or scaffold upon which a clot can form. Gelatin sponge does not become as readily
incorporated into the clot as does the oxidized regenerated cellulose. Healing is delayed more often
with cellulose than with the gelatin sponge, but oxidized regenerated cellulose is the more efficient
homeostatic agent.
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25. What is Avitene, and what is its mechanism of action?
Avitene is microfibrillar collagen. Unlike Gelfoam and surgical, Avitene provides an actual collagen
matrix, which then attracts platelets and triggers thrombus formation. It thus assumes an active rather
than a passive role in hemostasis.
26. Why is a conventional dental handpiece that expels forced air contraindicated
when performing dentoalveolar surgery?
Such an instrument can cause tissue emphysema or an air embolism. An air embolism can be fatal.
27. What are the cardinal signs and symptoms of a localized osteitis (dry socket)?
1. Throbbing pain (often radiating)
2. Bad taste
3. Fetidodor
4. A poorly healed extraction site, with clot loss and exposure of bone
28. Why is it contraindicated to curette a dry socket to stimulate bleeding?
Curetting a dry socket can cause the condition to worsen because healing will be further delayed,
any natural healing already taking place will be destroyed, and there is a risk of causing the localized
inflammatory process to be spread to the adjacent sound bone.
29. What is the treatment for a localized osteitis?
Conservative management is indicated. The wound should be irrigated gently with slightly warmed
saline, and a sedative dressing should be placed. The dressing should be removed within 48 hours and
replaced until the patient becomes asymptomatic. Systemic antibiotics are generally not indicated.
Nonsteroidal antiinflammatory analgesics may be prescribed, and narcotic analgesic may also be
indicated.
30. What causes a dry socket?
The etiology of a dry socket is not absolutely clear, but it is thought to develop because of increased
fibrinolytic activity causing accelerated lysis of the blood clot. Smoking, premature mouth rinsing, hot
liquids, surgical trauma, and oral contraceptives have all been implicated in the development of a dry
socket.
31. Why should flaps be repositioned and sutured over sound bone?
Unsupported flaps can collapse into bony defects, causing tension on the sutures. The sutures subse-
quently will pull through the tissue, allowing the suture line to open and the wound to dehisce.
32. What percentage of dentoalveolar injuries include the primary maxillary central
incisor?
70%.
33. How are avulsed primary teeth treated?
No treatment is necessary; replantation is not indicated for primary teeth.
34. How is an extruded primary tooth treated?
If there is gross mobility or interference with the opposing teeth, the tooth should be extracted. In
cases of very minor extrusion without significant mobility or occlusal interference, a primary tooth
may be repositioned without fixation, or left and kept under observation.
35. What is the incidence of pulp necrosis after intrusion injuries of teeth?
With intrusion injuries, the risk of pulp necrosis for a tooth with a closed apex is 95% and with an
immature apex is 65%. Accordingly, any form of luxation should be followed with routine clinical and
radiographic exams.
36. How long should dentoalveolar fractures be splinted?
4 to 6 weeks.
37. What media can be used to transport avulsed teeth?
Saliva, fresh milk, or, preferably, Hanks balanced salt solution (HBSS). Water is harmful because, as
a hypotonic fluid, it may cause periodontal ligament cell death when it enters cells down the osmotic
gradient, causing cell lysis and death.
Any tooth with an extraoral dry time of greater than 60 minutes will have a poor prognosis for
long-term success after replantation. Detailed protocols for management (based on dry time and
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whether the root apex is open or closed) are available on the website of the International Association
of Dental Traumatology.
38. How long should extruded or avulsed teeth be splinted?
Up to 2 to 3 weeks.
39. What are the significant radiologic predictions of a close relationship between the
inferior alveolar canal and the impacted mandibular third molar?
Signs of close proximity of the mandibular third molar to the inferior alveolar canal are mostly radio-
graphic in nature and include:
• Darkeningandnotchingoftheroot
• Deectedrootsattheregionofthecanal
• Narrowingoftheroot
• Interruptionofcanaloutlines
• Diversionofcanalfromitsnormalcourse
• Narrowingofcanaloutlinesontheradiograph
40. What are the most important signs that may increase potential nerve injury with
extraction of impacted mandibular third molars?
Of the previously listed signs of close proximity of the canal to impacted third molar, diversion of
canal, interruption of canal borders, and darkening of roots are the most reliable signs.
41. What are the possible complications of dentoalveolar surgery?
• Swallowingoraspirationofforeignobjects
• Tissueemphysema
• TMJpain
• Trismus
• Mandibularfracture
• Tuberosityfracture
• Rootfracture
• Injuriestoadjacentteeth
• Displacementofrootandrootfragmentsintothesubmandibularspace,mandibularcanal,ormaxil-
lary sinus
• Oral-antral communication, bleeding, infection, ecchymosis, and hematoma
• Localizedosteitis(drysocket)
• Wounddehiscence
• Inferioralveolarandlingualinjuries
Depending on the location and the nature of the surgery, these complications vary in severity and
need for treatment.
42. How are roots or root tips displaced into the submandibular space managed?
Once displacement of a mandibular molar root into the submandibular space is suspected, manual
lateral and upward pressure should be applied immediately on the lingual aspect of the floor of the
mouth in an attempt to force the root back into the socket. If the root is visualized again in the socket,
it may be retrieved from the socket with a root tip pick. If not, a mucoperiosteal soft tissue flap
should be reflected on the lingual aspect of the mandible until the root tip is found; ensure that the
mylohyoid muscle is sharply detached from its insertion in the mandible. Antibiotic coverage is indicated postoperatively. If the root is not visualized because of its location or uncontrollable bleeding,
recovery is best performed as a secondary procedure when fibrosis occurs and stabilizes the tooth
in a firm position, usually 4 to 6 weeks later. The patient should be informed and be placed on a short
course of antibiotics.
43. How are roots or root tips that are displaced into the inferior alveolar canal
managed?
When displacement of a root into the mandibular canal is suspected, periapical and occlusal radio-
graphs or cone beam CT scan should be taken for verification, because the root may be in a large
marrow space or beneath the buccal mucosa. If the root is visualized, careful removal is indicated
with a small hemostat after adequate alveolar bone removal. If the root is not visualized, delayed
removal is recommended. Delayed removal is also indicated during persistent infection and nerve
paresthesia. If the root fragment is small and does not become infected preoperatively, leaving the
root in place is a viable and less invasive option.
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44. How is a root or root fragment that is displaced into the maxillary sinus managed?
Once the root is suspected to be in the sinus, place the patient in an upright position to prevent pos-
terior displacement and obtain a radiograph or CT to determine its location and size. If the fragment is
found to be in the sinus, local measures of retrieval should be attempted first, such as:
• Havingthepatientblowthroughthenosewiththenostrilsclosed,andobservingtheperforationfor
the root to appear in the socket
• Usingafinesuctiontiptobringtherootbackintothedefect
• Performingantrallavagewithsterileisotonicsalineinanefforttoushtherootoutthroughthe
defect
If local measures are unsuccessful, direct entry into the maxillary sinus via the Caldwell-Luc approach
in the area of the canine fossa should be performed. Postoperative management includes a figure-ofeight suture over the socket (or flap closure if the opening is sizable), sinus precautions, antibiotics,
and a nasal spray to keep the sinus ostium open and infection free.
45. How are oral-antral communications managed?
Probing, irrigation, and having the patient blow forcefully with the nostrils occluded are contraindicated
because these maneuvers may enlarge an existing opening or create one that did not previously exist.
Some will allow patients to blow gently while compressing the nostrils to observe for air bubble forma-
tionsthatwillconfirmanantralopening.Foropenings<2mm,nosurgicaltreatmentisnecessary,providingadequatehemostasisisachieved.Foropeningsof2to6mm,conservativetreatmentisindicated,
including placement of a figure-of-eight suture over the tooth socket and sinus precautions (avoid
blowingthenose,violentsneezing,suckingonstraws,andsmoking).Foropenings>6mm,primary
closure should be obtained with a buccal flap or a palatal flap procedure. Approximation of the gingiva
can be facilitated by removal of a small amount of the buccal alveolar plate and scoring or incising the
periosteum on the underside of the flap. Placement of a small piece of absorbable gelatin sponge into
the occlusal third of the socket when the gingival margins cannot be coapted is not advisable because
it introduces a foreign substance and could lead to subsequent breakdown of the clot. Antibiotics and
nasal or oral decongestants are prescribed if there is evidence of acute or chronic sinusitis.
46. What steps should be taken for a tooth (maxillary third molar) that is displaced
into the infratemporal fossa?
When a maxillary third molar is displaced into the infratemporal fossa, it is usually displaced through
the periosteum and located lateral to the lateral pterygoid plate and inferior to the lateral pterygoid
muscle with displacement. If there is good access and adequate light, a single cautious effort to
retrieve the tooth with a hemostat can be made. If the effort is unsuccessful, or if the tooth is not
visualized, the incision should be closed, the patient should be informed, and prophylactic antibiotics
should be prescribed. A secondary surgical procedure is performed 4 to 6 weeks later after localization is determined using either lateral and posteroanterior radiographs or, preferably, a cone beam
CT scan. After adequate anesthesia, a long needle—usually a spinal needle—is used to locate the
tooth. Careful dissection is performed along the needle until the tooth is visualized and subsequently
removed. Some surgeons may prefer to perform this removal in the operating room for better access.
If no functional problems exist after displacement, the patient may elect not to have the tooth
removed. Proper documentation of this is critical.
47. How can postoperative or secondary bleeding from extraction sites be
managed?
The first step in managing postoperative bleeding is to carefully examine and visualize the bleeding
site to determine the precise source of bleeding. In the case of simple generalized oozing, a damp
gauze is held over the site with firm manual pressure for 5 minutes. If unsuccessful, the area should
be anesthetized and examined more closely. If sutures were placed, they should be removed and the
existing clot should be curetted from the socket. Hemostatic agents, such as an absorbable gelatin
sponge, oxidized cellulose, or Avitene can be placed in the socket and sutured. If hemostasis is not
achieved by local measures, lab screening tests should be performed to assist in diagnosis and treatment of the cause.
48. Why is it not indicated to scrape the walls of extraction sites after teeth are
removed?
Often, after using local anesthesia with a vasoconstrictor, the extraction site appears “dry” and the
void does not readily fill with blood. It is unnecessary and not a good practice to scrape the walls of
the extraction site to stimulate bleeding or for any other reasons. This practice will delay healing.
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The remnants of the periodontal ligament (PDL) that are attached to the alveolar crypt are the sources
of fibroblasts that form fibrin for the rudimentary clot (scaffold) upon which cells necessary for the
healing process can migrate. Moreover, the remnants of the PDL provide small capillaries and pluripotential cells that will form osteoblasts necessary for bone formation.
49. What is the proper positioning of a patient for exodontia procedures in the clinic
setting?
Formaxillaryprocedures,patientsarepositionedinasemireclinedposition,suchthatthemaxillary
occlusal plane is at an angle of about 60 degrees to the floor. This will normally correspond to a chair
tilt of about 30 to 45 degrees from vertical or upright. The height of the mouth should be at the operator’s elbow level.
Formandibularextractions,thepatientshouldbemoreupright,sothattheocclusalplaneof
the mandible is parallel to the floor when the mouth is opened. The patient will also be positioned
slightly lower than for maxillary extractions, with the chair at or slightly below the elbow level of the
operator.
Operators who choose to perform exodontia while sitting will need to make appropriate modifi-
cations to the standing positions.
50. Where is the location of the lingual nerve in relation to the mandibular third
molar?
The spatial relationship between the lingual nerve and the mandibular third molar region is highly
variable. The nerve has been found to be at the level of the lingual plate or higher, in contact with the
lingual plate, or intimately attached to the periosteum and the follicular sac of the impacted mandibular third molar.
51. What is the difference between an incisional and excisional biopsy?
An excisional biopsy entails removal of the entire lesion along with at least 2 mm of normal marginal
tissue from the sides of the lesion. This technique is usually used for biopsy of a lesion 1 cm or less.
An incisional biopsy removes only a representative portion or portions of a lesion along with a representation of adjacent normal tissue.
52. When a biopsy is being performed, why is it necessary to incise parallel to the
long axis of any muscle fibers beneath the lesion?
Whenever possible, the incisions should be oriented parallel to lines of muscle tension in order to
minimize scarring and wound dehiscence. Biopsy incisions on the face should be oriented to follow
Langer’s lines.
53. What are the indications for performing a partial odontectomy (coronectomy) of
an impacted mandibular molar?
An intentional partial odontectomy is usually performed on an impacted mandibular third molar. This
technique is chosen when there is a significant risk of injury to the inferior alveolar nerve or jaw
fracture, and in cases where the benefits of root retention outweigh the risks of conventional third
molar removal. The roots must be asymptomatic, not associated with pathologic lesions, and must not
interfere with future restorative procedures or orthodontic treatment. The technique involves careful
sectioning of the crown from the roots at or below the cementoenamel junction. The roots should not
be elevated or disturbed as they must remain attached to their apical blood vessels to ensure vitality.
The patient must always be informed when this technique is used.
54. On what relationships are the Pell and Gregory impacted mandibular third molar
classifications based?
The Pell and Gregory impacted third molar classifications are based on the third molar’s relationship
to the anterior border of the ascending ramus and to the occlusal plane. A Pell and Gregory Class
1 impaction implies sufficient space between the ramus and the second molar into which the third
molar can erupt. A Class 2 impacted third molar is found to be at least half covered by ramus bone.
The Class 3 impacted third molar is entirely within the ramus. With regard to the occlusal plane, a
Pell and Gregory Class A impaction implies that the occlusal surfaces of the second and third molars
are at or about the same level. The occlusal surface of a Class B third molar impaction is between
the occlusal surface and cementoenamel junction of the second molar. The Class C impaction is the
deepest impaction where the occlusal surface of the third molar is completely below the neck of the
second molar.
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55. What teeth are most commonly impacted?
The most commonly impacted teeth are the third molars (mandibular more frequently than maxillary),
followed in order by maxillary canines, mandibular premolars, and mandibular canines.
56. What is low molecular weight heparin (LMWH), and how is it used in oral and
maxillofacial surgery?
Standardunfractionatedheparin(UFH)isformedfromaheterogeneouscombinationofsulfated
mucopolysaccharides. Its anticoagulant activity is unpredictable, so it must be carefully monitored
with the partial thromboplastin time (PTT) test. LMWH (fractionated heparin) is formed from depolymerization of heparin into lower molecular weight particles. Because LMWH has increased bioavail-
abilitycomparedwithUFH,itcanbegivenasafixeddoseandwithouttheneedformonitoringwith
the PTT.
It is useful in oral and maxillofacial surgery for some higher risk patients who cannot discontinue
or reduce oral anticoagulation therapy. Patients stop warfarin therapy and the international normalized ratio (INR) is allowed to normalize while the LMWH is administered to maintain anticoagulation
therapy. When the INR returns to an acceptable level, the surgery can be performed and scheduled for
early in the day. The LMWH is withheld the day of surgery and resumed in the evening. Warfarin can
be resumed the following day and the LMWH continued until the INR returns to the desired therapeutic
range.
57. Should patients discontinue aspirin or Plavix (clopidogrel) for routine
dentoalveolar surgery?
While each patient must be evaluated on an individual basis, it is generally not indicated to stop
aspirin or Plavix prior to routine dentoalveolar procedures, including multiple extractions. Medical risks
of recurrent myocardial infarction or stroke will outweigh the risk of postoperative bleeding in most
cases.Formoreextensiveprocedureswherethereisaparticularconcernforbleeding,lowmolecular
weight heparin (e.g., Lovenox) can be used.
58. What are the “new oral anticoagulants,” and how are they monitored and adjusted
for patients undergoing surgery?
Rivaroxaban(Xarelto)andapixaban(Eliquis)aredirectFactorXainhibitors,anddabigatran(Pradaxa)
is a direct thrombin inhibitor. Neither the INR nor Protime (PT) levels have been shown to have any
reliability in monitoring therapy for these patients. Since the half-life of these agents is relatively short,
they can be held for one or two days prior to surgery, based on their respective half-life. As a general
rule,fordrugsgiventwicedaily(shorterhalf-life)holdforonedaypriortosurgery.Forthosegiven
once daily (longer half-life), hold for two days prior to surgery.
PREPROSTHETIC SURGERY
59. How does the blood supply of the edentulous mandible differ from that of the
dentate mandible?
As edentulous bone loss (EBL) progresses, there is a change in the blood supply to the mandible.
The inferior alveolar vessels become smaller. The primary blood supply to the dentate mandible
moves centrifugally from the inferior alveolar artery. The primary blood supply to the edentulous
mandible flows centripetally from the periosteum. Elevation of the periosteum on mandibles
that have had severe bone loss could compromise blood supply. Therefore, during surgical
procedures, elevation of the periosteum should be done judiciously in the edentulous atrophic
mandible.
60. Does alveolar bone resorb more quickly in the mandible or in the maxilla?
EBL in the maxilla is usually more rapid and severe. This may be due to the lack of muscle attach-
ments to the maxilla and, therefore, the lack of functional stimulus after tooth loss.
61. What skeletal relationship results from EBL?
The skeletal relationship that results from EBL is pseudo Class III. Most EBL in the maxilla takes
place on the lateral and inferior aspects of the ridge; therefore, the crest moves posteriorly and superiorly. As the height and width of the mandibular ridge deteriorate, the crest moves further anteriorly.
As vertical dimension collapses, the mandible autorotates forward as well.
CHAPTER 25 DENTOALVEOLAR SURGERY AND PREPROSTHETIC SURGERY 271
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62. How are edentulous alveolar ridges classified?
See Table 25-1.
63. What is combination syndrome?
Combination syndrome is excessive resorption of the edentulous alveolar ridge of the anterior maxilla,
caused by the forces generated by opposition of natural mandibular anterior teeth.
64. When and how are torus mandibularis and torus palatinus treated?
Mandibular tori usually need to be removed when a mandibular denture is being planned. The denture
flange typically will impinge on these exostoses of bone. Palatal tori often do not need to be removed.
Dentures often can be constructed over them. However, if a palatal torus is extremely large and fills
the vault, extends beyond the dam area, has traumatized mucosal coverage, has deep undercuts,
interferes with speech, or poses a psychologic problem for the patient, it should be removed.
The tissue over mandibular tori is extremely thin and friable. Great care should be taken when
elevating it. This tissue can be “ballooned” out by injecting some local anesthesia directly under it. The
incision should be crestal or lingual circumdental. No releasing incisions should be made. After careful
elevation of tissues, a groove can be cut along the intended line of removal with a fissure burr. A mallet
and osteotome may be used to cleave the torus in this plane. After the bone has been smoothed and
the area thoroughly irrigated, the wound can be closed. Gauze should be placed under the tongue to
minimize the chance of hematoma.
Before removing a palatal torus, a stent should be fabricated. This should be done on a study cast
that has had the exostosis removed. A double-Y incision should be made over the midline of the torus.
After careful elevation of the flaps, the torus should be scored multiple times in the anterior, posterior, and
transverse dimensions. An osteotome can be used to remove each of these small portions. This decreases
the risk of fracturing into the floor of the nose. A large burr or bone file is used to smooth the area. After
thorough irrigation, the wound is closed with horizontal mattress sutures, and the stent is placed.
65. How can an abnormal frenum be excised?
• Z-plasty
• V-Yadvancement
• Diamondexcision
66. What is the average size of the maxillary sinus?
The average size of the maxillary sinus is 14.75 cc, with a range of 9.5 to 20 cc. On average the width
is 2.5 cm; height, 3.75 cm; and depth, 3 cm.
Table 25-1. Classification of Edentulous Ridges
CLASS DEFINITION
Kent Classification of Edentulous Ridges (1986)
I Alveolar ridge is of adequate height but inadequate width, with lateral deficiencies
II Alveolar ridge deficient in both height and width, with a knife-edge appearance
III Alveolar ridge has been resorbed to the level of basilar bone, producing a concave
IV Resorption of the basilar bone, producing a pencil-thin, flat mandible or maxilla
Caywood Classification of Edentulous Ridges (1988)
I Dentate
II Immediately postextraction
III Well-rounded ridge form, adequate in height and width
IV Knife-edge ridge form, adequate in height but inadequate in width
V Flatridgeform;inadequateinheightandwidth
VI Depressed ridge form, with some basilar loss evident
or undercut areas
form in the posterior areas of the mandible and sharp ridge form with bulbous,
mobile soft tissues in the maxilla
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