Dentistry Fundamentals

# Dentistry Fundamentals Knowledge Pack

## Oral Anatomy Essentials

The adult dentition consists of 32 permanent teeth organized into quadrants using the Universal Numbering System (1-32, starting upper right third molar). Primary dentition has 20 teeth labeled A-T.

Tooth structure layers: enamel (hardest substance in body, 96% hydroxyapatite), dentin (bulk of tooth, contains dentinal tubules that transmit sensation), cementum (covers root surface), and pulp (neurovascular bundle providing vitality).

The perio structures (periodontium) include gingiva, perio ligament (PDL), alveolar bone, and cementum. Healthy sulcus depth is 1-3mm. Probing depths >4mm suggest perio disease. Clinical attachment loss (CAL) is the gold standard for perio dx.

Key anatomical landmarks: mental foramen (near premolars, contains mental nerve), mand canal (runs through mand body, contains inferior alveolar nerve), max sinus (pneumatized space above max post teeth — critical for implant planning), incisive canal (behind max central incisors).

## Common Procedures

### Diagnostic
- Comprehensive oral exam: extraoral/intraoral soft tissue exam, perio charting (6 points per tooth), occlusal analysis, TMJ evaluation
- Radiographic series: full mouth series (FMX = 18-20 films), bw radiographs (4 films for caries dx), pa films (single tooth evaluation), panoramic (broad overview)
- Caries dx: visual-tactile exam, bw radiographs, transillumination, DIAGNOdent laser fluorescence

### Preventive
- Prx (dental cleaning): scaling and polishing for pts with healthy perio. Adult prx recommended every 6 months
- Scaling and root planing (SRP): deep cleaning for perio disease. Performed per quadrant under local anes. Follow-up at 4-6 weeks to reassess
- Sealants: flowable resin placed in occl pits and fissures of post teeth. Most effective on newly erupted permanent molars in children
- Fluoride varnish: 5% NaF applied after prx. Particularly important for high-caries-risk pts

### Resto Procedures
- Direct restorations: comp resin (tooth-colored, bonded, technique-sensitive to moisture) or amal (silver-colored, self-sealing, less technique-sensitive). Comp preferred for ant teeth. Both acceptable for post teeth
- Indirect restorations: inlays (within cusps), onlays (cover one or more cusps), crowns (full coverage). Materials include porcelain-fused-to-metal (PFM), all-ceramic (e-max, zirconia), gold
- Crown prep involves reducing tooth structure 1.5-2mm on all surfaces, creating a finish line (chamfer or shoulder), and taking an impression or digital scan

### Endo Tx
- Root canal therapy: indicated when pulp is irreversibly inflamed or necrotic. Steps: access opening, working length determination (apex locator + pa radiograph), instrumentation (rotary NiTi files), irrigation (NaOCl 2.5-6%), obturation (gutta percha + sealer)
- Pulp testing: cold test (Endo-Ice), electric pulp test (EPT), heat test. Compare to adjacent and contralateral teeth
- Endo emergencies: irreversible pulpitis (spontaneous, lingering pain to thermal), pulp necrosis with acute apical abscess (swelling, pain to percussion)

### Perio Tx
- Gingivitis: reversible inflammation, bleeding on probing, no attachment loss. Tx with prx + oral hygiene instruction
- Periodontitis staging: Stage I (early, 1-2mm CAL), Stage II (moderate, 3-4mm CAL), Stage III (severe, >=5mm CAL, tooth loss <=4), Stage IV (advanced, extensive tooth loss)
- Surgical perio: flap surgery (access for debridement), osseous surgery (reshape bone defects), guided tissue regeneration (GTR with membranes + bone graft)

## Dental Materials

### Comp Resin
- Composition: BIS-GMA or UDMA matrix, silica/glass filler particles, coupling agent (silane)
- Types by filler size: microfill (polishable, weaker), hybrid (balance of strength + esthetics), nanofill (best overall properties)
- Bonding: etch-and-rinse (37% phosphoric acid, then primer + adhesive) or self-etch (combined acid + primer). Moisture control critical — rubber dam preferred
- Layering technique: 2mm increments to minimize polymerization shrinkage stress. Light cure 20 seconds per increment

### Ceramics
- Feldspathic porcelain: most esthetic, weakest. Used for veneers and layering on frameworks
- Lithium disilicate (e.max): 400 MPa flexural strength. Excellent for ant crowns, inlays, onlays
- Zirconia: 900-1200 MPa flexural strength. Preferred for post crowns and bridges. Newer translucent zirconia improving esthetics

### Impression Materials
- Alginate: irreversible hydrocolloid, used for study models and prx trays. Must pour within 10 minutes
- PVS (polyvinyl siloxane): addition silicone, excellent accuracy and dimensional stability. Standard for crown and bridge impressions
- Digital scanning: intraoral scanners (iTero, CEREC, 3Shape) replacing traditional impressions for many applications

## Pt Assessment

### Medical Hx Review
Critical conditions to screen for:
- Cardiovascular: hypertension (defer elective tx if BP >180/110), endocarditis risk (prosthetic valves, certain CHD — AHA guidelines for antibiotic prx), anticoagulant therapy (INR check for warfarin pts, consult physician)
- Diabetes: increased perio disease risk, delayed healing, risk of hypoglycemia during tx. HbA1c >9% — defer elective surgery
- Bisphosphonate therapy: risk of medication-related osteonecrosis of the jaw (MRONJ). Avoid extractions if possible, consult prescribing physician
- Allergies: latex, penicillin (use clindamycin alternative), local anes (true amide allergy rare — usually reaction to epinephrine or preservative)

### Risk Assessment
- Caries risk: low/moderate/high based on hx of caries, diet, fluoride exposure, saliva flow, bacterial load
- Perio risk: smoking (strongest modifiable risk factor), diabetes, genetics, stress, medications causing xerostomia
- ASA classification: ASA I (healthy), ASA II (mild systemic disease), ASA III (severe systemic disease), ASA IV (life-threatening). Most dental offices tx ASA I-III

## Emergency Protocols

### Medical Emergencies in Dental Office
- Syncope (most common): position pt supine, elevate legs, ammonia inhalant, monitor vitals
- Allergic reaction/anaphylaxis: epinephrine 0.3mg IM (adult EpiPen), call 911, oxygen, monitor airway
- Cardiac arrest: call 911, begin CPR (30:2 ratio), use AED. Every dental office must have emergency kit + AED
- Hypoglycemia: conscious pt — oral glucose (juice, glucose tablets). Unconscious — glucagon 1mg IM, call 911
- Aspiration of foreign body: encourage coughing. If complete obstruction, Heimlich maneuver. If object aspirated to lung, emergency transport

### Dental Emergencies
- Avulsed permanent tooth: handle by crown only, rinse gently (no scrubbing), reimplant within 60 minutes if possible. Store in Hank's balanced salt solution, milk, or saliva. Splint 7-10 days, endo tx in 2 weeks
- Dental fx classification: Ellis I (enamel only), Ellis II (enamel + dentin, sensitive), Ellis III (pulp exposed, bleeding). Ellis III requires pulp capping or endo tx
- Post-extraction hemorrhage: bite on gauze with firm pressure 30 min. If persistent, local hemostatic agents (Gelfoam, Surgicel), consider suturing. Check pt medications (anticoagulants)
- Acute perio abscess: drainage (through pocket or incision), SRP of affected area, systemic antibiotics if systemic signs (fever, lymphadenopathy). Amoxicillin 500mg TID x 7 days or clindamycin 300mg QID x 7 days if penicillin allergy