NBDE Dental Boards Oral Surgery-27

ORAL SURGERY Part 1: Principles of Surgery Indications for Dental Extractions 1) Severe caries 2) Pulpal necrosis/irreversible pulpitis where endo can’t be done 3) Severe perio dx 4) Orthodontic purposes (max./mand. 1PM and 3rd molars) 5) Malposed teeth 6) Cracked teeth 7) Preprosthetic extractions 8) Impacted teeth 9) Supernumerary teeth 10) Teeth assoc. w/ pathology 11) Pre-radiation therapy (questionable teeth should be extracted) Contraindications to Dental Extractions 1) Severe uncontrolled metabolic diseases (diabetes) 2) End-stage renal disease 3) Advanced cardiac conditions (unstable angina, uncontrolled HTN, recent MI) -should wait 6 months after CABG surgery to have elective extractions 4) Leukemia and lymphoma (should treat disease before extractions) 5) Head and neck radiation (can lead to osteoradionecrosis) -pts treated w/ hyperbaric oxygen prior to extractions 6) Pericoronitis (cellulitis) around mand. 3rd molars -should treat tissue infection before extraction (antibiotics, irrigation, and removing max. 3 rd molar) 7) Acute infectious stomatitis and malignant diseases 8) Treatment w/ IV bisphosphonates, chemo, anticoagulants, and steroids 9) Pregnancy in 1st and 3rd trimester 10) Severe bleeding disorders (hemophilia, thrombocytopenia) Forces Used in Routine Extractions 1) Luxation: loosening of tooth by progressive severing of PDL -force applied perpendicular to long axis of tooth 2) Rotation: used only on single-rooted teeth Indications for Surgical Extractions 1) Initial attempts at forceps extraction have failed 2) Pt appears to have heavy dense bone 3) Older pts due to loss of elastic bone 4) Short clinical crowns w/ severe attrition (bruxism) 5) Hypercementosis or widely divergent roots 6) Extensive decay or crown loss Positioning of Dentist When Extracting Teeth 1) Maxillary teeth: stand in front of or to side of pt -pt’s upper jaw should be at same height as dentist’s shoulder 2) Mand. teeth: stand directly to side of or behind pt -pt positioned so occlusal plane of mandible is parallel to floor and chair as low as possible Extracting Primary Teeth -primary direction of luxation should be to lingual b/c these teeth are more lingually positioned -opposite of adults

Sequence of Extractions 1) Maxillary teeth before mandibular teeth 2) Posterior teeth before anterior teeth Impacted Teeth -impacted teeth are ones that don’t erupt into arch in expected time -teeth become impacted b/c adjacent teeth, dense overlying bone, or excessive soft tissue prevents eruption -inadequate arch length is most common reason teeth fail to erupt -impacted teeth are retained for pt’s lifetime unless surgically removed -most common impacted teeth are mand. 3rd molars, max. 3rd molars, and max. canines -unerupted teeth include both impacted teeth and teeth in process of erupting -embedded teeth is used interchangeably w/ impacted teeth (Embedded teeth = Impacted teeth) -impacted max. 3rd molars can be displaced into: 1) infratemporal space -removed via hemostat 2) maxillary sinus -removed via Caldwell-Luc approach -mand. 3rd molars can be displaced into: 1) submand. space (most likely) 2) IA canal 3) cancellous bone space Caldwell-Luc Procedure -opening made into max. sinus by incision into canine fossa above max. PM roots -after tooth/root removal, figure-8 suture made, antibiotics, nasal spray, and decongestant given -palatal root of max. 1st molar is most often dislodged into sinus Reasons to Extract Impacted Teeth 1) Prevention of perio dx in adjacent teeth 2) Prevention of caries 3) Prevention of pericoronitis 4) Prevention of root resorption of adjacent teeth

5) Prevention of odontogenic cysts and tumors 6) Treatment of pain of unexplained origin 7) Prevention of jaw fractures 8) Facilitation of ortho txt

Contraindications to Extracting Impacted Teeth 1) Extremes of age (preteen or over 35 yrs old) 2) Compromised medical status 3) Likely damage to adjacent structures Classifications of Impacted Teeth 1) Angulation a) Mesioangular (least difficult for mand. and most difficult for max., most common) b) Horizontal c) Vertical d) Distoangular (most difficult for mand. and least difficult for max.) -most mand. 3rd molars angled to lingual 2) Pell and Gregory Classification a) Relationship to anterior border of ramus i) Class 1: normal position anterior to ramus ii) Class 2: half of crown is within ramus iii) Class 3: entire crown is within ramus b) Relationship to occlusal plane i) Class A: tooth at same plane as other molars ii) Class B: occlusal plane of 3rd molar is btw occlusal plane and cervical line of 2nd molar iii) Class C: 3rd molar is below cervical line of 2nd molar

Factors that Make Impaction Surgery Less Difficult 1) Mesioangular impaction 7) Large follicle 2) Class 1 ramus position 8) Elastic bone 3) Class A depth 9) Separated from 2nd molar 4) Roots 1/3 to 2/3 formed (2/3 is best) 10) Separated from IA nerve 5) Fused, conic roots 11) Soft tissue impaction 6) Wide PDL Factors that Make Impaction Surgery More Difficult 1) Distoangular 7) Thin follicle 2) Class 3 ramus position 8) Dense, inelastic bone 3) Class C depth 9) Contact w/ 2nd molar 4) Long, thin roots 10) Close to IA canal 5) Divergent, curved roots 11) Complete bony impaction 6) Narrow PDL Principles of Surgical Extractions 1) Exposure -surgeon must have adequate visibility of surgical site (make flap) -incision should be made over sound bone -envelope flap is most often used, but can also use releasing incisions -vertical releasing incisions should be made at line angle of tooth, never on facial aspect or splitting papilla -base of flap (vestibule) should always be wider than apex (crest) to maintain blood supply to soft tissues 2) Bone removal -better to remove bone w/ bur than to fracture it through forceful extraction -trough of bone on buccal down to cervical line should be removed initially, and more if needed depending on position and root morphology 3) Tooth sectioning -sectioning tooth may be needed to avoid excess bone removal or injury to vital structures -mand. 3rd molars are teeth most often needed to be sectioned 4) Irrigation of wound -copious irrigation impt to avoid leaving bone spicules or tooth fragments below soft tissue flap Complications of Extractions 1) Tearing of mucosal flap 2) Puncture wounds in palate, tongue, etc. -control bleeding and allow healing by secondary intention 3) Oral-antral communication -manage w/ figure 8 suture over socket, antibiotics, and nasal spray -if very small, just let blood clot form -if very large, then close w/ flap procedure -complications: chronic oroantral fistula and max. sinusitis 4) Root fracture 5) Tooth displacement a) max. molar into max. sinus (palatal root of max. 1st M most common) b) max. 3rd molar into infratemporal fossa c) mand. molar roots forced into submandibular space d) tooth lost into oropharynx (may cause airway obstruction, should take to ER for chest x-rays) 6) Injury to adjacent teeth 7) Alveolar process fractures (max. tuberosity) -if tuberosity fxs completely off, then smooth sharp edges of bone and suture soft tissue -if fxns but still intact, then manually reposition and stabilize w/ sutures -tuberosity fx most often occurs on lone-standing molars or extraction of last molar in arch 8) Trauma to inferior alveolar nerve (mand. 3rd molars)

9) Excessive bleeding a) injury to IA artery b) arteriolar bleed from elevating flap c) pt’s hemostasis (warfarin, hemophilia, von Willebrand’s, chronic liver deficiency) 10) Infections (rare) 11) Dry socket (localized alveolar osteitis) -occurs in 3% of mand. 3rd molar extractions 12) Air emphysema (from nonsurgical handpieces) Dry Socket -caused by increased fibrinolytic activity, causing loss of blood clot in extraction site -smoking and oral contraceptives have been indicated, as well as rinsing, hot liquids -most common in mandibular molars (most common complication seen after mand. molar extraction) -signs: worsening throbbing pain, radiating pain, bad odor and taste, poor healing extraction site -treatment: irrigation w/ saline, sedative dressing (eugenol) changed every 2 days until asymptomatic, and analgesics (no antibiotics needed) Extraction Tips -sequence of extraction should be maxillary before mandibular and posterior to anterior -first force applied should be apical -B-L forces are less effective in mand. posterior teeth due to dense bone -normal saline should be used for irrigation b/c it is isotonic -distilled water is hypotonic and can cause cell lysis Alveoloplasty -indicated in any area that may cause difficulty in denture construction Tori Removal -only need to be removed for denture fabrication -palatal tori removal: 1) make stent pre-op 2) double-Y incision made over midline of torus 3) osteotome used to remove in small portions -should not remove en masse b/c can enter into nose by removing palatine bone 4) large bur used to smooth area 5) close wound w/ horizontal mattress suture and place stent to prevent hematoma Mandibular Ridge Surgery for Complete Dentures -may need to excise labial/lingual frenum, mylohyoid ridge, or exostoses -do not remove genial tubercles, even if large, b/c they are attachment for suprahyoid muscles -tongue would then be flaccid Soft Tissue Surgery -soft tissue may need to be removed/remodeled for dentures 1) Mand. retromolar pad 2) Max. tuberosity 3) Excessive alveolar ridge tissue 4) Inflammatory fibrous hyperplasia 5) Labial/lingual frenum

Principles of Suturing 1) Needle should be perpendicular when entering tissue 2) Sutures should be placed at equal distance from wound margin (2-3mm) and at equal depths 3) Sutures should be placed from mobile to nonmobile tissue 4) Sutures should be placed from thin tissue to thick tissue 5) Sutures should not be overtightened or closed under tension 6) Sutures should be 2-3mm apart 7) Suture knot should be on the side of the wound -suturing usually not necessary on single-tooth extraction unless severe bleeding or gingiva torn -if bleeding persists for long time, have them bite on tea bag b/c tannic acid promotes hemostasis Sutures -as suture diameter decreases, strength decreases -size 0 suture is average size -adding 0’s means they are getting smaller (4-0 smaller than 3-0) -assigning positive numbers means suture size increases (2, 3, 5, etc) -smallest diameter suture that is sufficient to keep wound closed should be used -3-0 and 4-0 most common in dental surgery -can be resorbable or nonresorbable 1) resorbable: gut, polyglactin (vicryl), polyglycolic acid (dexon), polydixanone -plain gut made form sheep intestine and rapidly digested -chromic gut is chromitized to be more resistant to proteolytic enzymes 2) nonresorbable: nylon, silk, polypropylene -must be removed in 5-7 days Interrupted vs Continuous Suture Techniques 1) Interrupted: each suture is independent -offers strength and flexibility in placement -if one suture comes loose, integrity of remaining sutures not compromised -disadvantage: requires more time 2) Continuous: many sutures placed that are connected -ease and speed of placement -distributes tension over whole suture line -gives more watertight closure than interrupted pattern Dead Space -any area that remains devoid of tissue after closure of wound -created by removing tissues in depths of wound or not reapproximating tissue planes during closure -dead space usually fills in w/ blood to form hematoma w/ high potential for infxn -can eliminate dead space by: 1) closing wound in layers 2) apply pressure dressings 3) use drains 4) place packing into void until bleeding stops Wound Healing 1) Primary intention: occurs in closely approximated wound edges -lower risk of infxn and minimal scar formation 2) Secondary intention: occurs when large gap btw incision edges -requires larger amt of epithelial migration, collagen deposition, contraction, and remodeling -slower healing and more scar formation (granulation tissue) -granulation tissue is weaker than original tissue -factors that impair wound healing: foreign material, necrotic tissue, ischemia, tension, systemic conditions

Stages of Wound Healing 1) Inflammatory stage: from time of injury to 2-5 days -hemostasis (vasoconstriction, clot formation) and inflammation (vasodilation, phagocytosis) -neutrophils and lymphocytes predominate 2) Proliferative stage: 2 days to 3 weeks -epithelialization, angiogenesis, granulation tissue formation, and collagen deposition -fibroblasts predominate 3) Remodeling/Maturation stage: 3 weeks to 2 years -collagen fibers increase tensile strength and contraction occurs Stages of Hemostasis 1) Vascular phase: vasoconstriction 2) Platelet phase (Primary hemostasis): platelet and collagen interaction leading to platelet plug 3) Coagulation phase (Secondary hemostasis): cascade of coagulation factors 4) Repair process: growth of fibroblasts and smooth muscle, fibrinolysis of clot How to Achieve Hemostasis 1) Pressure 2) Sutures 3) Electrocautery 4) Thrombin 5) Cellulose sheet (Surgicel)

6) Gelatin sponge (Gelfoam) 7) Bone wax (Parafin/Beeswax) 8) Tranxenamic acid 9) Microfibrillar collagen

Dental Implants -factors that need to be considered: 1) Primary stability 2) Amount of bone 3) Anatomic structures (sinus, other teeth, IA nerve) -loss of teeth for extended time can lead to ridge resorption (esp. mand.) and ridge augmentation may be needed (bone grafting) -common sites for autogenous bone grafts include: 1) iliac crest 3) anterior cortex of chin (small areas of bone) 2) rib 4) lateral cortex of ramus/external oblique ridge -allogenic grafting also possible -PAN and CT scan should be used in implant txt planning -most popular type of implants used are root-form implants Bone Augmentation Surgery 1) Max. sinus grafts to augment max. alveolar ridge 2) Bone grafts a) Autograft: transplanted from one region to another in same person -gold standard for bone regenerative properties b) Allograft: Transplanted from one individual to genetically non-identical person on same species -freeze-dried bone is most common allogenic graft c) Xenograft: transplanted from one species to a difft species -smokers, alcoholics, uncontrolled diabetes, or uncontrolled systemic dx are poor candidates for bone grafting d) Isograft: transplanted from individual of same species who is genetically related to recipient e) Alloplastic graft: inert, man-made synthetic material 3) Guided Tissue Regeneration: membranes used to hinder migration of fibrous CT while supporting growth of bone 4) Alveolar distraction osteogenesis: has goal of lengthening mandible 10-12mm -bone fragments moved physiologically and new bone forms in distraction zone -0.5-1mm increments of movement per day w/ 1mm movement not to be exceeded in 24 hrs 5) Mandible augmentation: augmentation of atrophic mand. indicated in pt w/ less than 8mm bone height Types of Implant Integration

1) Osseointegration: direct and fxnal connection btw living bone and implant surface -most predictable long-term stability 2) Fibro-osseous integration: CT-encapsulated implant within bone -50% success rate over 10 yrs 3) Biointegration: achieved via bioactive materials (hydroxyapatite or bioglass) -develop bone faster than noncoated implants, but little difference seen after one year Osseointegration -direct adaptation of bone to dental implant -defined histologically as being evident at light microscope level -implant success criteria defined as: 1) implant immobile clinically 2) no peri-implant radiolucency present 3) mean vertical bone loss less than 0.2mm annually 4) no pain or infxn 5) implant placement doesn’t inhibit placement of crown/prosthesis Contraindications to Implant Placement 1) Uncontrolled diabetes 4) Bisphosphonate therapy 2) Immunocompromised 5) Bruxism 3) Anatomic considerations 6) Tobacco use (relative contraindication) -also contraindicated to place implants immediately after extraction tooth w/ active infxn (wait 8 weeks) Anatomic Limitations to Implant Placement 1) Buccal plate (0.5mm) 6) Interimplant distance (3mm) 2) Lingual plate (1mm) 7) IA canal (2mm) 3) Max. sinus (1mm) 8) Mental nerve (5mm) 4) Nasal cavity (1mm) 9) Inferior border of mandible (1mm) 5) Incisive canal (avoid midline max.) 10) Adjacent tooth (0.5mm) -need 10mm of bone height to place implant -implants placed in anterior maxilla have highest failure rate Stages of Implant Placement 1) Implant placement -can use surgical stent to achieve proper angulation and parallelism -cooling saline spray used during bone prep and implant placement to keep bone temp. under 47 degrees C (116 F) 2) Healing abutment placement 3) Prosthetic restoration of implant Implants Restoring Edentulous Maxilla -at least 4-8 implants placed at least 10mm depth to achieve cross-arch stabilization of prosthesis Implants Restoring Edentulous Mandible 1) Tissue-born prosthesis: placed over 2-4 implants 2) Implant-born prosthesis: placed over 5 implants, all placed in anterior mandible anterior to mental foramen

Part 2: Trauma Surgery Tooth Fractures 1) Crown craze/crack (infraction): no loss of tooth structure 2) Horizontal or vertical crown fracture: can be confined to enamel, or include dentin and/or pulp 3) Crown-root fracture: may or may not involve pulp a) More than 1/3 root involved: extract b) Less than 1/3 root involved: RCT c) Primary teeth: extract 4) Horizontal root fracture: located in apical, middle, or cervical/coronal third a) Coronal: remove segment and perform RCT b) Apical/middle: rigid splint for 2-3 months 5) Concussion: injury to tooth-supporting structure causing sensitivity to percussion but no mobility/displacement -no txt needed 6) Subluxation: injury to tooth supporting structures resulting in mobility but no displacement -splint for 7-10 days 7) Intrusion: displacement of tooth into socket -often assoc. w/ compression fracture of socket -splint for 14 days; may need to await re-eruption or require orthodontic extrusion -no txt for intruded primary teeth, just let them re-erupt 8) Extrusion: partial displacement of tooth out of socket -splint for 14 days 9) Labial or lingual displacement: alveolar wall fractures probable 10) Lateral displacement: displacement of tooth in mesial or distal direction -alveolar wall fractures probable 11) Avulsion: complete displacement of tooth from its socket -may have alveolar wall fracture -replant and splint 7-10 days -do not replant primary teeth 12) Alveolar process fracture -reduce dentoalveolar segment and rigid splint (arch bar) for 4-6 weeks Facial Fractures -facial fractures should always be considered after car accidents, fights, falls, or sports accidents -signs of facial fracture include: 1) pain 5) abnormal mobility of bone 9) malocclusion 2) contour deformity 6) numbness (CN V-3) 10) step defect 3) ecchymosis 7) crepitation 11) mobility of mandible segments 4) laceration 8) hematoma/ecchymosis of FOM -when there is lip laceration w/ fractured tooth, always take soft tissue radiograph to detect any broken fragments of tooth material -txt goals of maxillofacial fractures: control hemorrhage, restore occlusion, reduction and stabilization of fractured segments -fat embolism is most often a sequelae of fractures -highest incidence of fractures occurs in males btw 15-24 yrs old from trauma Zygomatic Arch Fractures -best visualized by submental vertex view -complications: paresthesia (most common) sinus hematoma, impaired ocular muscles

Mandible Fractures -can almost always be seen on PAN radiograph, but should be visualized in at least two radiographs -PAN, Townes, P-A skull, lateral oblique -malocclusion is most pathognomic sign of mand. fx -mandible is 2nd most common fractured facial bone and 50% are multiple fractures -most common sites for mandible fractures: 1) Condyle: 29% 5) Alveolar process: 3% 2) Angle: 25% 6) Ramus: 2% 3) Symphysis: 22% 7) Coronoid: 1 4) Body: 16% -fracture of condyle will result in deviation on opening to fractured side from trauma to ipsilateral lateral pterygoid muscle -fractures can be classified as: 1) Simple (closed): no communication w/ external environment 2) Compound (open, complex): communication w/ external environment (skin, mucosa, or PDL) -Infection common 3) Comminuted: fractured in multiple pieces 4) Greenstick: one side of bone is broken and other is bent -most often seen in children b/c bone more elastic 5) Pathologic: occurred at weakened site due to pre-existing disease 6) Favorable: not displaced by forces of muscles of mastication 7) Unfavorable: displaced by forces of muscles of mastication -line of fracture determines whether muscles will be able to displace fractured segments -bilateral mandible fractures may result in posterior displacement of tongue causing airway obstruction -contemporary txt for mand. fxs that are displaced and mobile is with open reduction and internal fixation w/ titanium plates and screws -other methods of repair include lingual splinting (pedo pts) and intermaxillary fixation (wire jaws closed) -prolonged immobilization of condylar fxs will lead to ankylosis of TMJ so condylar fxs should only be immobilized for 2 weeks Open vs Closed Reduction for Mandibular Fractures 1) Open reduction: involves direct exposure and reduction of fx though surgical incision 2) Closed reduction: external fixation devices and intermaxillary fixation Midface Fractures -midface fxs best evaluated w/ CT scans of face -both axial and coronal orientations needed to fully evaluate fractures -can involve maxilla, zygoma, nose, and orbits -orbital floor fracture is termed “blowout fracture” -zygomaticomaxillary complex (tripod) fractures are most common midface fx (40%) -maxillary fractures classified as: 1) LeForte I (transverse maxillary): separation of maxilla only with intact nasofrontal complex -signs: malocclusion (open bite), buccal vestibule ecchymosis (Guerin’s sign), epistaxis 2) LeForte II (pyramidal): separation of maxilla and nasal complex from cranial base (mobile nasofrontal complex) -signs: malocclusion (open bite), perioribtal edema, subconjunctival hemorrhage, paresthesia of infraorbital nerve 3) LeForte III (craniofacial dysjxn): complete separation of midface at level of naso-orbitalethmoid complex (mobile nasofrontal and malar complexes) -major sign is rhinorrhea from CSF leaking into nasal cavity -also have restricted mand. movement

4) Zygomaticomaxillary complex fracture (ZMC): cheek bone fx w/ flattening of malar process -zygomatic arch fx has “W” deformity on submental vertex radiograph and CT scan -maxilla, orbit, and zygomatic fxs require rigid internal fixation -isolated zygomatic fxs can often be reduced w/ minor surgery and w/o use of plates and screws -Gillies approach: long elevator inserted through superficial temporal fascia to pop zygomatic arch back into position -simple nasal fractures are repaired w/ internal and external splints -nasal bone fracture is most common facial fracture Bone Healing 1) Primary bone healing: direct attempt by cortex to re-establish itself 2) Secondary bone healing: involves classical stages of fx healing -phases of bone healing: 1) Hemorrhage: blood clot organization and proliferation of vessels occurs in first 10 days 2) Callus formation: primary callus formed in 10-20 days and secondary callus forms in 20-60 days 3) Fxnal reconstruction: mechanical forces cause Haversian systems to line up according to stress lines -excess bone is removed and shape of bone molded -takes 2-3 yrs to completely reform fx Inappropriate Bone Healing 1) Delayed union: satisfactory healing that requires greater than normal 6 wk period 2) Non-union: failure of fx segments to unite properly 3) Mal-union: delayed or complete union in improper position Reasons for Fractures Not Healing 1) Ischemia 2) Excessive mobility 3) Interposition of soft tissue 4) Infection Part 3: Orthognathic Surgery Evaluating Need for Orthognathic Surgery -pts evaluated according to normal facial proportions -vertically, face is divided into equal thirds -horizontally, face is divided into equal fifths Angle Classifications of Occlusion 1) Angle class I: normal dental occlusion w/ straight (orthognathic) profile 2) Angle class II: mand. 1st molars and canines are in posterior position relative to max. counterparts -face appears posteriorly convergent (retrognathic) 3) Angle class III: mand. 1st molars and canines are in anterior position relative to max. counterparts -face appears anteriorly convergent (prognathic) Imaging for Orthognathic Surgery -lateral cephs are main imaging used, although PANs, A-P cephs, and PAs are taken as needed -cephalometric analysis helps determine which jaw is involved primarily in deformity, direction of growth of jaws, and most ideal procedure for pt

Diagnoses of Dentofacial Deformities 1) Max. hyper/hypoplasia 2) Mand. hyper/hypoplasia 3) Anterior open bite (apertognathic) 4) Vertical max. excess (max. too long w/ gummy smile) 5) Horizontal transverse discrepancy (pt has posterior crossbite) 6) Macrogenia (chin too big) or microgenia (chin too small) 7) Cant (vertical asymmetry) Maxillary Surgery -referred to LeForte I osteotomies -maxilla can be moved forward and down more easily than up or back -maxilla can also be sectioned into two or three segments to better position the occlusion Mandibular Surgery -most often done using one of two osteotomies: 1) Sagittal split osteotomy: ramus is divided by horizontal osteotomy on medial aspect and vertical osteotomy on lateral aspect -lateral and medial aspects then separated and mand. advanced or set back 2) Vertical ramus osteotomy: ramus cut vertically and mand. positioned forward or back -mandible can be moved anteriorly to correct retrognathia (class II) or posteriorly to correct prognathia (class III) -chin can be moved using a genial osteotomy (genioplasty) to correct macrogenia or microgenia Distraction Osteogenesis -involves cutting an osteotomy to separate segments of bone and application of an appliance that will facilitate the gradual and incremental separation of bone segments which will fill in with new bone Cleft Lip and Palate -cleft LIP more common in males -CL is defect in fusion of lateral and medial nasal processes -cleft PALATE more common in females -CP is lack of fusion btw palatal shelves -most commonly found on Asians and least common in AA -CL/P surgery follows rule of 10s: surgery performed when child is at least 10 weeks old, weighs at least 10 lbs, and has at least 10 g/dL Hb Part 4: Facial Pain and Neuropathology Physiology of Pain 1) Transduction: activation of A-delta and C-fibers to spinal cord or brain stem 2) Transmission: pain info in CNS is sent to thalamus and cortex for processing of sensory/emotional aspects 3) Modulation: limits rostral flow of pain info from spinal cord and trigeminal nucleus to higher cortical centers -acute pain lasts 3 months or less -chronic pain is pain lasting longer than 4-6 months Classification of Orofacial Pain 1) Somatic pain: increased stimulus leads to increased pain a) musculoskeletal pain (TMJ, perio, muscular) b) visceral (salivary gland, pulp) 2) Neuropathic pain: pain independent of stimulus activity -damage to pain pathways (trigeminal neuralgia, trauma, stroke) 3) Psychogenic pain: caused by intrapsychic disturbance -conversion rxn, psychotic delusion, malingering 4) Atypical pain: facial pain of unknown cause

Trigeminal Neuralgia (Tic Douloureaux) -a trigger point exists where pain typically presents as electrical, sharp, shooting sensation -triggered by wind, tactile, or thermal stimulation -pain is episodic (seconds to minutes) followed by refractory period -usually unilateral -no motor or sensory deficits present -treatment: 1) anticonvulsant drugs: gabapentin, carbamazepine 2) surgically: microvascular decompression (Janetta procedure), gamma knife radiosurgery 3) Conservative: night guard, soft diet, motion exercises, moist heat, massage, NSAIDs Atypical Odontalgia (Odontalgia Secondary to Deafferentation) -occurs as result of trauma or surgery (RCT or extraction) -these result in damage to afferent pain transmission system -proposed mechanisms: 1) peripheral hyperactivity at surgical site 2) CNS hyperactivity secondary to changes in 2nd-order nerve in trigeminal nucleus Postherpetic Neuralgia -sequelae of herpes zoster infxn -pain is burning, aching, or electric shock-like -treatment: 1) anticonvulsants 2) antidepressants 3) sympathetic blocks -Ramsay-Hunt syndrome: herpes zoster infxn of sensory and motor branches of CN VII and VIII, resulting in facial paralysis, vertigo, deafness, and cutaneous eruption of external auditory canal Neuromas -can occur after a nerve injury -proximal section of transected nerve forms sprouts filled w/ Schwann cells -becomes very sensitive to stimuli and can cause chronic neuropathic pain Burning Mouth Syndrome -pts complain of pain, dryness, burning of mouth and tongue, and altered taste -most common in postmenopausal females -thought to be secondary to defect in pain modulation -symptoms of 50% of pts resolve w/o txt in 2-yr period -hormone therapy, anticonvulsants, and antidepressants NOT useful Chronic Headaches 1) Migraine a) Onset: acute b) Location: unilateral c) Symptoms: nausea, vomiting, photophobia, phonophobia d) Pain: throbbing e) Duration: prolonged f) Diagnostic test: check for hx of symptoms g) Prior hx of headaches: yes 2) Cluster a) Onset: acute b) Location: unilateral c) Symptoms: rhinorrhea, lacrimation of ipsilateral side d) Pain: sharp, stabbing e) Duration: 30 mins to 2 hrs f) Diagnostic test: history of symptoms g) Prior hx of headaches yes

3) Tension a) Onset: chronic b) Location: global and unilateral c) Symptoms: multisomatic complaints d) Pain: aching e) Duration: daily f) Diagnostic test: none g) Prior hx of headaches: yes 4) Temporal Arteritis a) Onset: acute or chronic b) Location: localized c) Symptoms: weight loss, polymyalgia, fever, vision problems, jaw claudication d) Pain: severe throbbing pain e) Duration: prolonged f) Diagnostic test: erythrocyte sedimentation rate test (ESR), tender temporal arteries g) Prior hx of headaches: no -can lead to blindness on affected side if not treated quickly Nerve Injuries 1) Anesthesia: loss of sensation 2) Paresthesia: abnormal sensation (burning, tingling, etc.) 3) Hyperesthesia: increase in sensitivity 4) Dysesthesia: painful sensation to normal stimulus 5) Neurapraxia: mild injury w/ no axonal damage (spontaneous recovery within 4 weeks) 6) Axonotmesis: axonal damage but intact endoneural and perineural sheath -Wallerian degeneration occurs distal to injury -Potential for recovery in 1-3 months 7) Neurotmesis: complete severance of axon with a gap created -no recovery expected w/o surgery Part 5: Temporomandibular Disorders TMJ -classified as ginglymoarthrodial joint w/ both translational and rotational movement -synovial joint -anatomy: 1) TMJ: articulation btw condyle of mandible and squamous portion of temporal bone 2) Articular surface of temporal bone: fxnal aspect of TMJ made of dense fibrous CT a) concave portion: articular fossa (glenoid/mandibular fossa) b) convex portion: articular eminence (tubercle) 3) Articular disc: dense fibrocartilagenous CT (avascular and aneural) -separates joint into inferior and superior joint spaces -anterior/posterior bands: thick (post. band thicker and attached to retrodiscal tissues) -intermediate zone: thin (center of disc) 4) Retrodiscal tissues: loose CT that is vascular and innervated Myofascial Pain Disorder -most common cause of masticatory pain/TMJ pain and compromised fxn -diffuse, poorly localized pain in preauricular region, often involving muscles of mastication -pain and tenderness result from abnormal muscle fxn and hyperactivity, as well as spasm and dysfxn -parafunctional habit may be etiologically related (wear facets often seen) -if pt has nocturnal parafunctional habit, symptoms are worse in morning -can also be result of disc displacement disorders and degenerative arthritis -is stress-related disorder (increased stress causes increased muscle tension/bruxism)

Disc Displacement Disorders -assoc. w/ synovial inflammation -disc displacement is end result of inflammation and chronic joint overloading -disc most often displaced in anteromedial direction 1) Disc displacement w/ reduction: disc returns to normal disc-to-condyle relationship -normal interincisal opening w/o deviation can be seen -opening click corresponds to condyle moving over posterior portion of anteriorly displaced disc (reduction) -second click occurs when jaw is closed and disc fails to maintain its normal reduced relationship to condyle 2) Disc displacement w/o reduction: disc doesn’t return to normal position -results in limited range of motion and ipsilateral deviation on opening -no popping or clicking observed 3) Internal derangement: abnormal relationship of articular disc to mand. condyle and fossa -posterior band of disc is anteriorly displaced in front of condyle as disc translates anteriorly, posterior band remains in front of condyle leading to inflammation of retrodiscal tissue causing decreased production of synovial fluid and decreased mobility Degenerative Joint Disease (DID) 1) Osteoarthritis 2) Systemic Arthritic Conditions a) Systemic lupus (SLE) b) Rheumatoid arthritis c) Crystalline arthropathies (calcium pyrophosphate dehydrate (pseudogout)) 3) TMJ ankylosis -most commonly caused by trauma Chronic Recurrent Dislocation -occurs when mand. condyle translates anterior to articular eminence -assoc. w/ pain and muscle spasm -requires mechanical manipulation to achieve reduction -when problem becomes chronic (multiple recurrences), Botox txt to lateral pterygoid and surgery may be needed Ankylosis -pt presents w/ severely restricted range of motion and limited interincisal opening w/ pain -bony ankylosis results in more limitation of motion than fibrous ankylosis -trauma is most common cause of ankylosis, but surgery, radiation therapy, and infxn can also cause it Nonsurgical Therapy for TMD -txt objectives are to decrease pain symptoms and improve fxn -in cases of ankylosis and severe symptomatic degenerative joint disorders, surgery may be right choice -nonsurgical therapy includes: 1) Patient education/counseling: prevent parafxnal habits, reduce stress, etc. 2) Physical therapy: biofeedback, ultrasound, electrical nerve stimulation, massage, exercise -results in increased circulation to affected region 3) Pharmacotherapeutic intervention: NSAIDs, steroids, narcotics/analgesics, antidepressants, muscle relaxants 4) Occlusal considerations: equilibration, prosthetics, ortho, orthognathic surgery, and splints a) Autorepositioning splints: used for muscle and joint pain when no specific anatomic cause can be found -work by reducing intra-articular pressure -allows for no working or balancing interferences w/ full arch contact b) Anterior repositioning splint: protrudes mandible into forward position, recapturing normal disc-to-condyle relationship

Surgical Treatments for TMD 1) Arthrocentesis: benefits pts w/ internal derangement -needles placed into superior joint space and saline injected to reduce inflame. mediators -thought to distend joint capsule, release adhesions, and remove chemical mediators assoc. w/ joint pathology 2) Arthroscopy: placement of two cannulas to allow access for intracapsular instrumentation of superior joint space -lysis of adhesions, steroid injxn, and motorized shaving of osteoarthritic fibrillation tissue 3) Disc repositioning surgery (Open arthoplasty): disc is mobilized and posterior wedge may be removed and disc repositioned into more desirable position -used in pts w/ painful, persistent clicking-popping and closed lock 4) Disc repair/removal (Discectomy): indicated when disc is severely damaged -if disc is removed, it can be replaced w/ autogenous materials (temporalis muscle, fat, articular cartilage) or prosthetics 5) Condylotomy: accomplished by performing an intraoral vertical ramus osteotomy -allows soft tissues to passively reposition the condyle and disc into more fxnally neutral position 6) Total joint replacement: indicated in severely pathologic joints (rheumatoid arthritis, deg. Joint. Dx, ankylosis, neoplasia) -costochondral bone graft reconstruction is most common autogenous material used -totally prosthetic joints can also be made -should AVOID occlusal adjustments, prosthetic restorations, ortho txt, and orthognathic surgery Approaches to Expose TMJ 1) Pre-auricular incision: perpendicular incision anterior to external ear -is best way to expose TMJ 2) Submandibular approach (Risdon approach): standard approach to ramus and neck of condyle -not best way to approach joint space Part 6: Odontogenic Infections Microorganisms Causing Odontogenic Infections -polymicrobial infections 1) Anaerobic (75%) a) Gram neg. rods: most (Bacteroides, Fusobacterium) b) Gram pos. cocci (Strep) 2) Aerobic (25%) a) Gram pos. cocci (most) Strep, Staph Pathologic Mechanism -highly virulent Strep species initiate infectious process in deep tissues -cellulitis then occurs (aerobic), followed by proliferation of anaerobic organisms (form abscess) -aerobic organisms consume the oxygen, making environment more favorable for anaerobes -disease progresses by following path of least resistance, often through bone cortex and invading fascial space (most often enter vestibular space) -can drain spontaneously and result in asymptomatic, chronic draining fistula Fascial Space Infections 1) Vestibular 5) Submandibular 2) Buccal 6) Submental 3) Canine 7) Masticator (pterygomand., masseteric, superficial/deep temporal) 4) Sublingual 8) Lateral pharyngeal -these are referred to as potential spaces, b/c in healthy state there is no real space; abscess formation causes cavities in these fascial planes -spaces are contiguous w/ each other and as abscess spreads, more spaces can become involved -canine and deep temporal space infxns can result in cavernous sinus thrombosis via ophthalmic veins -lateral pharyngeal space infxns can spread to mediastinum -both should be considered life-threatening emergencies

Ludwig’s Angina -bilateral infxn of submandibular, sublingual, and submental spaces -can lead to blockage of airway Six Treatment Principles for Odontogenic Infections 1) Determine severity of infxn 2) Evaluate state of pt’s host defense mechanisms 3) Determine whether pt should be treated by general dentist or specialist 4) Treat infxn surgically -remove source of infxn and decompress/drain purulence -goal is to get adequate drainage so spread of infxn can be brought under control -specimen for culture and sensitivity should be obtained 5) Support pt medically -airway management, hydration, electrolytes, antibiotics, analgesics 6) Choose and prescribe appropriate antibiotics -Pen VK is preferred drug for odontogenic infxns -if allergic, then clindamycin or clarithromycin are good -narrow spectrum agents are better than board spectrum for odontogenic infxns b/c alter normal flora less -bactericidal agents better than bacteriostatic Indications for Antibiotic Use 1) Rapidly progressing swelling 4) Fascial space involvement 2) Diffuse swelling 5) Severe pericoronitis 3) Compromised host defenses 6) Osteomyelitis -pseudomembranous colitis (C. dificile) can result from antibiotic use of amoxicillin, clindamycin, and cephalosporins -treat w/ vancomycin or metronidazole Osteomyelitis -inflammation of medullary portion of bone -osteomyelitis spreads via infxn, inflammation, and ischemia -most common initiating causes are odontogenic infxns and trauma -infxn begins in medullary space of cancellous bone, then spreads to cortical bone, periosteum, and soft tissues -occurs more often in immunocompromised and in mandible over maxilla -causative agents are similar to odontogenic infxns (Strep, anaerobic cocci and gram- rods) -treatment done by debridement and antibiotics Necrotizing Fasciitis -rapidly progressing infxn of skin and fascia w/ high mortality rate (30-50%) -caused by group-A strep or C. perfringens -treated w/ surgical debridement and antibiotics Cavernous Sinus Thrombosis -retrograde infxn from backflow of material drained from face -CN III, IV, V-1, and VI involved Sinusitis 1) Acute (less than 1 month) -S. pneumonia, H. influenzae, M. catarrhalis 2) Chronic (over 3 months) -results from obstruction of sinus drainage -diabetics may develop mucormycosis (fungal infxn) 3) Txt: amoxicillin or augmentin (amoxicillin+clavulanate), antihistamines, or surgery to establish drainage 4) Complications of sinusitis: orbital cellulitis, cavernous sinus thrombosis, meningitis, osteomyelitis

Animal Bite Infections -caused by Pasteurella multicida -txt w/ ampicillin or amoxicillin Part 7: Biopsies Biopsy Technique -block anesthesia preferred b/c injection into lesion can distort the architecture and make diagnosis difficult 1) Suction: use low volume suction wrapped in gauze so not to aspirate the specimen -hemostasis is impt so a high volume suction isn’t needed 2) Incision: use sharp scalpel to avoid excessive damage to tissue and achieve clearly defined margins 3) Laser: carbon dioxide laser in super-pulsed mode is acceptable if hemostasis concerns are significant -a fine peripheral zone of necrosis does occur w/ laser 4) Handling/tagging: if suspect malignancy, a tissue tag should be used to help identify orientation -tissue should be placed in 10% formalin in volume 20x that of specimen 5) Records: biopsy data sheet must be filled out including pt hx and clinical findings Oral Brush Cytology 1) Uses: detecting cancerous and precancerous lesions 2) Method: cytology brush placed over lesion and rotated 5-10 times to obtain cells from all 3 epithelial layers -cells transferred to glass slide and fixative placed and sent to lab -one of 3 categories assigned: a) Negative: no evidence of atypical cells or carcinoma b) Positive: definitive evidence of atypical cells or carcinoma c) Atypical: abnormal epithelium -all positive and atypical finding should undergo definitive scalpel biopsy Aspiration Biopsy (Fine Needle Aspiration) 1) Uses: low morbidity and high diagnostic accuracy for most lesions -also used to determine if lesion is vascular or not before surgical exploration 2) Method: special syringe and needle used to collect cells from clinically or radiographically identified mass Incisional Biopsy 1) Uses: when lesion is large (>1cm), polymorphic, suspicious for malignancy, or in high morbidity area 2) Method: portion of lesion is incised and must be obtained in a representative area of the lesion, avoiding areas of necrosis and in adequate depth to make definitive histological diagnosis Excisional Biopsy 1) Uses: for smaller lesions (