18.2 Impacted Teeth & Minor Oral Surgery
Key Takeaways
- Winter’s classification describes third molar angulation (mesioangular, horizontal, vertical, distoangular); Pell & Gregory grades depth (A/B/C) and ramus relationship (I/II/III), with deep Class C-III cases signaling high difficulty.
- Surgical third molar removal generally follows flap elevation, controlled bone removal, tooth sectioning as needed, elevation of segments, debridement, and closure while protecting the lingual and inferior alveolar nerves.
- Panoramic proximity signs of the IAN canal warrant caution; CBCT and specialist options such as coronectomy may be considered when roots are intimate with the canal.
- Incisional biopsy samples part of large or suspicious lesions for diagnosis before definitive therapy; excisional biopsy removes small, clinically benign lesions entirely—brush cytology is not a cancer rule-out substitute.
- Pericoronitis is managed with local toilet, opposing trauma control, and selective antibiotics for systemic involvement, with extraction planned when acute risks are controlled.
18.2 Impacted Teeth & Minor Oral Surgery
Quick Answer: Impacted teeth—especially third molars—are classified by angulation (Winter) and depth/ramus relationship (Pell & Gregory). Surgical extraction follows a sequence: anesthesia → flap → bone removal → sectioning → elevation → debridement → closure. Minor oral surgery also includes biopsy selection (incisional vs excisional), soft-tissue procedures, and risk counseling for IAN/lingual injury.
Impaction: Definition and Etiology
An impacted tooth fails to erupt into functional occlusion within the expected time due to lack of space, obstruction, malposition, or pathology. Third molars are most common; canines, premolars, and supernumeraries also impact.
Why remove (selected indications)
- Recurrent pericoronitis
- Non-restorable caries on third molar or distal of second molar
- Periodontal destruction distal to second molar
- Cyst/tumor associated with follicle (e.g., dentigerous cyst)
- Orthodontic or prosthodontic needs
- Resorption of adjacent roots
- Fracture involvement of the angle region in some trauma plans
When observation may be reasonable
- Fully bony impacted, asymptomatic, no pathology on imaging, adequate counseling and follow-up—shared decision-making, especially in older adults with higher morbidity
AFK items often hinge on pericoronitis management (irrigate, relieve soft-tissue trauma, antibiotics if systemic signs, extract when acute phase controlled) versus immediate heroic removal in severe trismus/airway risk.
Winter’s Classification (Angulation)—Mandibular Third Molars
Based on the long-axis relationship of the third molar to the second molar:
| Winter class | Orientation | Relative difficulty notes |
|---|---|---|
| Mesioangular | Crown tipped toward second molar | Often most common; may be favorable if path of withdrawal improves with sectioning |
| Horizontal | Long axis roughly perpendicular | Often difficult; crown locked under second molar; sectioning common |
| Vertical | Parallel to second molar | Difficulty depends on depth and root form |
| Distoangular | Crown tipped distally | Frequently difficult—path of withdrawal into ramus |
| Buccoangular / linguoangular / inverted | Other malpositions | Plan 3D path carefully; CBCT when risk high |
Distoangular and deep horizontal impactions are classic “harder than they look” exam favorites.
Pell & Gregory Classification
Combines depth relative to the occlusal plane and space relative to the ramus.
Relation to occlusal plane (Class A/B/C)
| Class | Definition |
|---|---|
| A | Occlusal plane of third molar at/near level of second molar occlusal plane |
| B | Occlusal plane between occlusal plane and cervical line of second molar |
| C | Occlusal plane below cervical line of second molar (deepest) |
Relation to ramus (Class I/II/III)
| Class | Definition |
|---|---|
| I | Sufficient space between distal of second molar and ramus for crown |
| II | Space less than mesiodistal crown width (partially in ramus) |
| III | All/nearly all of tooth within ramus (least space) |
Class C-III combinations signal high surgical difficulty and higher complication rates—counsel and refer when beyond skill/setting.
Maxillary Third Molar Considerations
- Often more vertical or distoangular
- Risks: maxillary tuberosity fracture, oroantral communication, displacement into infratemporal fossa or sinus
- Root fusion and conical forms may allow simpler delivery after luxation
- Flap design must respect buccal fat pad and limited distal access
Radiographic Risk Assessment for IAN Injury
2D panoramic clues of proximity (Rood & Shehab–type signs often tested conceptually):
- Darkening of the root
- Deflection of the canal or roots
- Interruption of white lines of the canal
- Narrowing of the canal or root
When high-risk signs present, CBCT may clarify buccolingual relationship. Options include coronectomy in selected cases (roots left intentionally when intimate with canal—specialist decision), referral, or staged approaches.
Surgical Extraction Steps (Impacted Mandibular Third Molar)
- Profound anesthesia — IAN block + long buccal ± lingual infiltration; confirm anesthesia
- Flap — typically envelope or triangular distal/buccal flap; protect lingual tissues (lingual nerve runs near crest distal to second molar/third molar region)
- Bone removal — buccal gutter/trough with irrigation; avoid excessive lingual plate removal
- Tooth sectioning — separate crown from roots or split mesial/distal roots as needed to create a path of withdrawal
- Elevation — controlled elevator use on tooth segments, not adjacent second molar as fulcrum
- Follicle removal / socket toilet — curette follicle remnants carefully; inspect for pathology
- Hemostasis and bony recontouring — remove sharp edges
- Suture — primary or partial closure based on surgeon preference and bleeding
- Post-op instructions — swelling peaks ~48 hours; steroids sometimes used perioperatively by surgeons; analgesics; smoking cessation
Pericoronitis-specific notes
- Operculum trauma from opposing tooth—consider occlusal adjustment/extraction of opposing maxillary third molar
- Irrigate under flap of tissue; chlorhexidine adjuncts
- Extract after acute infection is controlled unless drainage requires removal earlier under controlled conditions
Other Minor Dentoalveolar Procedures
| Procedure | Essence | AFK relevance |
|---|---|---|
| Operculectomy | Remove excess soft tissue over partially erupted tooth | Limited role if tooth will still impact; extraction often definitive |
| Frenectomy | Release high frenum | Speech, diastema, denture stability contexts |
| Alveoloplasty | Smooth ridge after extractions | Prosthetic preparation |
| Torus removal | Exostoses interfering with prosthesis | Flap design over bone, careful lingual torus (hematoma/airway) |
| Incision & drainage | Evacuate pus from abscess | Combined with source control (extract/RCT) |
| Preprosthetic soft-tissue | Vestibuloplasty concepts | Specialist-heavy; know goals |
Biopsy Principles
Any lesion that is suspicious, persistent (>2 weeks without clear cause), or changing needs diagnosis—not endless empiric steroid gels alone.
Incisional vs excisional biopsy
| Type | Definition | When preferred |
|---|---|---|
| Incisional | Sample a representative portion | Large lesions, suspected malignancy, diffuse disease (need diagnosis before definitive ablation) |
| Excisional | Remove entire lesion with margin | Small, clinically benign lesions amenable to complete removal |
| Aspiration / FNA | Needle sampling fluid/cells | Cystic vs solid triage; neck nodes (medical/surgical pathways) |
| Brush cytology | Surface cells | Adjunct only—not a substitute for scalpel biopsy when cancer suspected |
High-yield biopsy technique rules
- Include interface of lesion and normal tissue when helpful for pathologist (esp. white/red patches)
- Adequate depth—do not skim only keratin
- Avoid crushing with forceps (use sutures for traction)
- Multiple samples if heterogeneous lesion
- Radiograph radiolucencies appropriately; some require surgical exploration with histopathology
- Label orientation when margins matter
- Never place tissue in the wrong fixative for special studies without thinking (routine histopathology: formalin)
What not to do
- Do not “watch” a non-healing ulcer >2 weeks in high-risk patients without biopsy pathway
- Do not electively excise what you believe is cancer without staging plan—incisional diagnosis first for large suspicious masses
- Pigmented lesions: specialist pathways; incomplete handling can compromise diagnosis
Soft-Tissue Handling and Sutures (Quick Map)
| Suture concept | Notes |
|---|---|
| Resorbable (e.g., chromic gut, Vicryl) | Common intraoral mucosa |
| Non-resorbable (silk, nylon) | Need removal ~5–7 days often |
| Interrupted | Reliable for most sockets/flaps |
| Figure-of-eight | Socket hemostasis / some OAC aids |
| Horizontal mattress | Eversion/tension distribution |
Complications Specific to Third Molars
- Swelling, trismus, pain (expected ranges vs progressive infection)
- Alveolar osteitis
- Secondary infection / fascial space involvement
- IAN or lingual nerve injury
- Adjacent tooth damage
- Mandibular fracture (rare; more with deep impactions/atrophic jaws/excessive force)
- Displacement of tooth/root
Rapid review list
- Winter = angulation; Pell-Gregory = depth (A/B/C) + ramus space (I/II/III)
- Distoangular and deep C-III impactions are high difficulty
- Panoramic red flags near IAN → consider CBCT / referral / coronectomy concepts
- Surgical sequence: flap → bone → section → elevate → close
- Protect lingual nerve during distal third molar surgery
- Incisional biopsy for large/suspicious lesions; excisional for small benign-appearing lesions
- Cytology does not replace tissue biopsy when malignancy is in the differential
Section 18.3 shifts from elective dentoalveolar surgery to maxillofacial and dental trauma classification and emergency priorities.
A mandibular third molar crown is tipped toward the second molar, with its occlusal surface below the cervical line of the second molar and most of the tooth within the ramus. Which combined classification best fits?
Which biopsy strategy is most appropriate for a 3 cm indurated, non-healing ulcer of the lateral tongue highly suspicious for squamous cell carcinoma?
During surgical removal of a mandibular third molar, which soft-tissue principle best reduces lingual nerve injury risk?
A panoramic radiograph shows darkening of the third molar roots and interruption of the inferior alveolar canal white lines. What is the best next conceptual step before extraction?