Stomatology Technology Qualification (China) cheat sheet

Enamel: 96% inorganic by weight, hydroxyapatite crystals ~95 nm thick and 25-100 nm wide; prism rods run from DEJ to surface, gnarled in outer third, Hunter-Schreger bands reflect rod decussation.

Dentin: ~70% inorganic, 20% organic (mainly type I collagen), 10% water; dentinal tubules ~1-2.5 µm diameter, denser near pulp (45,000/mm² near pulp vs 20,000/mm² near DEJ); peritubular dentin more mineralized than intertubular.

Pulp: loose connective tissue with odontoblasts, fibroblasts, and a rich capillary bed; pulp pressure ~ 5-20 mmHg; A-delta fibers (myelinated) mediate sharp dentinal pain, C fibers (unmyelinated) mediate dull, aching pain.

Periodontal ligament: principal fibers (alveologingival, dentogingival, transseptal, alveolar crest, horizontal, oblique, apical, interradicular) - oblique fibers are the most numerous and resist axial load; PDL width 0.15-0.38 mm, narrower in function.

Saliva: resting flow ~0.3-0.4 mL/min, stimulated ~1.5-2.0 mL/min; pH 6.7-7.4; main buffers are bicarbonate, phosphate, and salivary proteins; xerostomia raises caries risk.

Dental caries microbiology: Streptococcus mutans and S. sobrinus are key acidogenic/aciduric cariogens; Lactobacillus contributes to progression; Actinomyces viscosus implicated in root caries.

Key pharmacology: lidocaine 2% with 1:100,000 epinephrine gives ~60-90 min pulpal anesthesia; maximum epinephrine dose ~0.2 mg in healthy adults; articaine 4% has higher lipid solubility and protein binding than lidocaine.

Oral pathology markers: leukoplakia and erythroplakia are clinical terms without a specific histologic diagnosis; erythroplakia has higher malignant transformation risk than leukoplakia; squamous cell carcinoma is the most common oral malignancy.

Ideal dental material properties: high elastic modulus and strength, low thermal diffusivity, coefficient of thermal expansion (CTE) close to tooth structure (enamel ~11.4 ppm/°C, dentin ~8.3 ppm/°C), biocompatibility, and dimensional stability.

Amalgam: silver-tin (gamma) phase reacts with mercury to form gamma-1 (Ag2Hg3) and gamma-2 (Sn7-8Hg); gamma-2 is the weakest and most corrosion-prone phase, so high-copper alloys reduce it.

Composite resin: bisphenol-A-glycidyl dimethacrylate (Bis-GMA) matrix with triethylene glycol dimethacrylate (TEGDMA) diluent, silane-treated filler, camphorquinone photoinitiator; filler load 60-87 wt% controls shrinkage, strength, and polishability.

Glass ionomer cement: fluoroaluminosilicate glass powder plus polyacrylic acid liquid; sets by acid-base reaction; releases fluoride, bonds chemically to tooth, and is moisture-sensitive during initial set.

Zinc phosphate cement: exothermic setting, pH ~3.5 at placement rising toward neutral; high compressive strength but no chemical adhesion; zinc polycarboxylate bonds to calcium in tooth.

Gypsum products: Type I impression plaster, Type II model plaster (beta-hemihydrate), Type III dental stone, Type IV improved stone, Type V high-expansion stone; water/powder ratio controls setting expansion and strength.

Elastomeric impressions: addition silicone (polyvinyl siloxane) has low polymerization shrinkage and high dimensional stability; condensation silicone shrinks by by-product evaporation; polysulfide has high tear strength but poor dimensional stability and odor.

Casting alloys: high-noble (≥60% noble, ≥40% Au), noble (≥25% noble), predominantly base metal (Ni-Cr, Co-Cr); Ni-Cr requires higher casting temperature and has greater hardness than high-noble alloys.

Tooth preparation convergence: recommended total occlusal convergence ~6-10° for retention; greater taper reduces retention; minimal occlusal reduction ~1.0-1.5 mm for metal-ceramic and ~1.5-2.0 mm for all-ceramic.

Wax pattern: sprue diameter should be at least as large as the thickest part of the pattern; sprue attaches at the bulkiest point and directs metal into the mold; pattern should be invested within a short time to limit distortion.

Casting: phosphate-bonded investment for metal-ceramic and high-fusing alloys; gypsum-bonded for low-fusing; burnout temperature depends on alloy; casting shrinkage of gold alloys ~1.25-1.5% compensated by investment expansion.

Metal-ceramic: coefficient of thermal expansion of the alloy should slightly exceed that of the veneering porcelain; metal framework minimum thickness ~0.3-0.5 mm; opaque layer masks metal and provides the bond.

All-ceramic: zirconia (tetragonal-to-monoclinic transformation toughening) has flexural strength ~900-1,200 MPa; lithium disilicate ~360-450 MPa; feldspathic porcelain ~70-100 MPa; glass-ceramics can be etched with HF and bonded.

CAD/CAM workflow: intraoral or laboratory scan, digital design, then subtractive milling or additive printing; zirconia requires sintering shrinkage compensation of ~20-25%; fit of milled crowns typically 50-100 µm marginal gap.

Soldering: use lower-fusing solder than the parent alloy; gap should be minimal; flux removes oxides; avoid overheating that distorts or softens the framework.

Finishing and polishing: use progressively finer abrasives; remove casting nodules and sprue remnants; margins should be finished to a smooth continuous surface; avoid creating scratches that concentrate stress.

Complete denture record bases: shellac or light-cured resin bases must be stable and adapted; occlusion rims reproduce lip support, occlusal plane, and vertical dimension of occlusion.

Occlusal scheme: bilateral balanced occlusion in complete dentures uses compensating curves (curve of Spee, curve of Wilson, Christensen phenomenon) to maintain contacts in excursions.

Articulation: semi-adjustable articulators use facebow transfer and protrusive records; Hanau's equation L = H/8 + 12 relates condylar guidance, incisal guidance, cusp height, and compensating curve.

Removable partial denture design: rests provide vertical support, clasps provide retention and bracing, major connector rigidly connects; Kennedy classification I-IV and Applegate's rules guide design.

Denture processing: compression molding with heat-cured PMMA; polymerization shrinkage ~0.4-0.6% by volume; long curing cycle reduces residual monomer and porosity; pressure curing minimizes porosity.

Repairs: fracture repair requires clean, roughened surfaces and a repair resin; a lingual or palatal reinforcement can be added; repair of a fractured metal clasp requires soldering or replacement.

Relines: chairside reline with autopolymerizing resin; laboratory reline with heat-cured resin; tissue conditioner is a temporary soft reline material used to condition inflamed mucosa.

Denture teeth selection: posterior tooth form should match condylar guidance and patient needs; monoplane teeth reduce lateral forces; anterior teeth selected by size, shape, and shade to match facial features.

Removable appliances: Hawley retainer uses a labial bow and Adams clasps; active plates use screws, springs, or elastics; anchorage is provided by clasps and baseplate coverage.

Functional appliances: activator, twin block, and Frankel appliance reposition the mandible to influence growth; they require adequate patient compliance and are most effective during growth.

Space maintainers: band-and-loop and crown-and-loop maintain space after premature loss of primary molars; a lower lingual holding arch maintains leeway space; a Nance appliance uses a palatal button for anchorage.

Model analysis: mixed dentition analysis uses Tanaka-Johnston or Moyers prediction of unerupted premolar and canine size; arch length discrepancy compares available space with required space.

Cephalometric landmarks: SNA, SNB, and ANB angles assess sagittal jaw relationships; ANB 2-4° suggests a Class I skeletal pattern; Frankfort horizontal and SN plane are reference planes.

Retainers: Hawley and clear vacuum-formed retainers are removable; fixed lingual retainers are bonded; retention is needed because relapse occurs from periodontal and soft tissue forces.

Pediatric considerations: primary teeth have thinner enamel and dentin and larger pulp chambers; pulpotomy and stainless steel crowns are common; eruption timing guides appliance design.

Growth: mandibular growth continues into late adolescence; maxillary growth completes earlier; cervical vertebral maturation stages estimate skeletal maturity for timing treatment.

Obturators: a surgical obturator is placed at surgery, a provisional obturator during healing, and a definitive obturator after healing; the bulb seals the defect and restores speech and swallowing.

Facial prostheses: silicone elastomers (platinum-cured) are used for auricular, nasal, and orbital prostheses; retention by adhesives, eyeglasses, or implants; color matching and margins are critical.

Implant framework: a screw-retained framework requires passive fit; misfit can cause screw loosening, fracture, or bone loss; verification with a one-piece cast or sectioned and soldered framework.

Abutment selection: internal and external connections; platform switching reduces crestal bone loss; abutment height and angulation determine retention and path of insertion.

Attachment systems: stud attachments (ball, locator) provide retention for overdentures; bar attachments splint implants; magnets provide minimal retention and are used in selected cases.

Implant loading: immediate loading requires adequate primary stability (insertion torque ≥ 30-35 Ncm); delayed loading allows osseointegration; splinting distributes load.

Obturator design: hollow bulb reduces weight; the defect side must be extended to seal; the remaining teeth and implants provide support, retention, and stability.

Maxillofacial materials: silicone, acrylic resin, and polyurethane; silicone is flexible and lifelike but degrades with UV and requires replacement; acrylic is rigid and durable but less lifelike.

Disinfection: impressions and prostheses should be disinfected before laboratory handling; sodium hypochlorite, glutaraldehyde, and iodophors are common; follow manufacturer contact times.

Sterilization: autoclave at 121°C for 15-20 min or 134°C for 3-4 min; dry heat at 160°C for 2 h; chemical vapor; biological indicators (Geobacillus stearothermophilus for steam) verify sterilization.

Waste handling: sharps in puncture-resistant containers; regulated medical waste separated from general waste; amalgam waste recycled; follow local regulations.

Occupational safety: eye protection, masks, gloves, and gowns; ventilation for monomer and dust; noise control; ergonomic design to prevent musculoskeletal disorders.

Laboratory management: quality assurance includes calibration of equipment, documentation, and traceability; equipment maintenance schedules for articulators, casting machines, and ovens.

Cross-contamination: use separate clean and dirty areas; label cases; transport in sealed containers; hand hygiene before and after handling cases.

Chemical safety: material safety data sheets (MSDS) for all chemicals; proper storage and labeling; ventilation for volatile materials; spill kits available.

Enamel: 96% inorganic by weight, hydroxyapatite crystals ~95 nm thick and 25-100 nm wide; prism rods run from DEJ to surface, gnarled in outer third, Hunter-Schreger bands reflect rod decussation.

Dentin: ~70% inorganic, 20% organic (mainly type I collagen), 10% water; dentinal tubules ~1-2.5 µm diameter, denser near pulp (45,000/mm² near pulp vs 20,000/mm² near DEJ); peritubular dentin more mineralized than intertubular.

Pulp: loose connective tissue with odontoblasts, fibroblasts, and a rich capillary bed; pulp pressure ~ 5-20 mmHg; A-delta fibers (myelinated) mediate sharp dentinal pain, C fibers (unmyelinated) mediate dull, aching pain.

Periodontal ligament: principal fibers (alveologingival, dentogingival, transseptal, alveolar crest, horizontal, oblique, apical, interradicular) - oblique fibers are the most numerous and resist axial load; PDL width 0.15-0.38 mm, narrower in function.

Saliva: resting flow ~0.3-0.4 mL/min, stimulated ~1.5-2.0 mL/min; pH 6.7-7.4; main buffers are bicarbonate, phosphate, and salivary proteins; xerostomia raises caries risk.

Dental caries microbiology: Streptococcus mutans and S. sobrinus are key acidogenic/aciduric cariogens; Lactobacillus contributes to progression; Actinomyces viscosus implicated in root caries.

Key pharmacology: lidocaine 2% with 1:100,000 epinephrine gives ~60-90 min pulpal anesthesia; maximum epinephrine dose ~0.2 mg in healthy adults; articaine 4% has higher lipid solubility and protein binding than lidocaine.

Oral pathology markers: leukoplakia and erythroplakia are clinical terms without a specific histologic diagnosis; erythroplakia has higher malignant transformation risk than leukoplakia; squamous cell carcinoma is the most common oral malignancy.

Ideal dental material properties: high elastic modulus and strength, low thermal diffusivity, coefficient of thermal expansion (CTE) close to tooth structure (enamel ~11.4 ppm/°C, dentin ~8.3 ppm/°C), biocompatibility, and dimensional stability.

Amalgam: silver-tin (gamma) phase reacts with mercury to form gamma-1 (Ag2Hg3) and gamma-2 (Sn7-8Hg); gamma-2 is the weakest and most corrosion-prone phase, so high-copper alloys reduce it.

Composite resin: bisphenol-A-glycidyl dimethacrylate (Bis-GMA) matrix with triethylene glycol dimethacrylate (TEGDMA) diluent, silane-treated filler, camphorquinone photoinitiator; filler load 60-87 wt% controls shrinkage, strength, and polishability.

Glass ionomer cement: fluoroaluminosilicate glass powder plus polyacrylic acid liquid; sets by acid-base reaction; releases fluoride, bonds chemically to tooth, and is moisture-sensitive during initial set.

Zinc phosphate cement: exothermic setting, pH ~3.5 at placement rising toward neutral; high compressive strength but no chemical adhesion; zinc polycarboxylate bonds to calcium in tooth.

Gypsum products: Type I impression plaster, Type II model plaster (beta-hemihydrate), Type III dental stone, Type IV improved stone, Type V high-expansion stone; water/powder ratio controls setting expansion and strength.

Elastomeric impressions: addition silicone (polyvinyl siloxane) has low polymerization shrinkage and high dimensional stability; condensation silicone shrinks by by-product evaporation; polysulfide has high tear strength but poor dimensional stability and odor.

Casting alloys: high-noble (≥60% noble, ≥40% Au), noble (≥25% noble), predominantly base metal (Ni-Cr, Co-Cr); Ni-Cr requires higher casting temperature and has greater hardness than high-noble alloys.

Tooth preparation convergence: recommended total occlusal convergence ~6-10° for retention; greater taper reduces retention; minimal occlusal reduction ~1.0-1.5 mm for metal-ceramic and ~1.5-2.0 mm for all-ceramic.

Wax pattern: sprue diameter should be at least as large as the thickest part of the pattern; sprue attaches at the bulkiest point and directs metal into the mold; pattern should be invested within a short time to limit distortion.

Casting: phosphate-bonded investment for metal-ceramic and high-fusing alloys; gypsum-bonded for low-fusing; burnout temperature depends on alloy; casting shrinkage of gold alloys ~1.25-1.5% compensated by investment expansion.

Metal-ceramic: coefficient of thermal expansion of the alloy should slightly exceed that of the veneering porcelain; metal framework minimum thickness ~0.3-0.5 mm; opaque layer masks metal and provides the bond.

All-ceramic: zirconia (tetragonal-to-monoclinic transformation toughening) has flexural strength ~900-1,200 MPa; lithium disilicate ~360-450 MPa; feldspathic porcelain ~70-100 MPa; glass-ceramics can be etched with HF and bonded.

CAD/CAM workflow: intraoral or laboratory scan, digital design, then subtractive milling or additive printing; zirconia requires sintering shrinkage compensation of ~20-25%; fit of milled crowns typically 50-100 µm marginal gap.

Soldering: use lower-fusing solder than the parent alloy; gap should be minimal; flux removes oxides; avoid overheating that distorts or softens the framework.

Finishing and polishing: use progressively finer abrasives; remove casting nodules and sprue remnants; margins should be finished to a smooth continuous surface; avoid creating scratches that concentrate stress.

Complete denture record bases: shellac or light-cured resin bases must be stable and adapted; occlusion rims reproduce lip support, occlusal plane, and vertical dimension of occlusion.

Occlusal scheme: bilateral balanced occlusion in complete dentures uses compensating curves (curve of Spee, curve of Wilson, Christensen phenomenon) to maintain contacts in excursions.

Articulation: semi-adjustable articulators use facebow transfer and protrusive records; Hanau's equation L = H/8 + 12 relates condylar guidance, incisal guidance, cusp height, and compensating curve.

Removable partial denture design: rests provide vertical support, clasps provide retention and bracing, major connector rigidly connects; Kennedy classification I-IV and Applegate's rules guide design.

Denture processing: compression molding with heat-cured PMMA; polymerization shrinkage ~0.4-0.6% by volume; long curing cycle reduces residual monomer and porosity; pressure curing minimizes porosity.

Repairs: fracture repair requires clean, roughened surfaces and a repair resin; a lingual or palatal reinforcement can be added; repair of a fractured metal clasp requires soldering or replacement.

Relines: chairside reline with autopolymerizing resin; laboratory reline with heat-cured resin; tissue conditioner is a temporary soft reline material used to condition inflamed mucosa.

Denture teeth selection: posterior tooth form should match condylar guidance and patient needs; monoplane teeth reduce lateral forces; anterior teeth selected by size, shape, and shade to match facial features.

Removable appliances: Hawley retainer uses a labial bow and Adams clasps; active plates use screws, springs, or elastics; anchorage is provided by clasps and baseplate coverage.

Functional appliances: activator, twin block, and Frankel appliance reposition the mandible to influence growth; they require adequate patient compliance and are most effective during growth.

Space maintainers: band-and-loop and crown-and-loop maintain space after premature loss of primary molars; a lower lingual holding arch maintains leeway space; a Nance appliance uses a palatal button for anchorage.

Model analysis: mixed dentition analysis uses Tanaka-Johnston or Moyers prediction of unerupted premolar and canine size; arch length discrepancy compares available space with required space.

Cephalometric landmarks: SNA, SNB, and ANB angles assess sagittal jaw relationships; ANB 2-4° suggests a Class I skeletal pattern; Frankfort horizontal and SN plane are reference planes.

Retainers: Hawley and clear vacuum-formed retainers are removable; fixed lingual retainers are bonded; retention is needed because relapse occurs from periodontal and soft tissue forces.

Pediatric considerations: primary teeth have thinner enamel and dentin and larger pulp chambers; pulpotomy and stainless steel crowns are common; eruption timing guides appliance design.

Growth: mandibular growth continues into late adolescence; maxillary growth completes earlier; cervical vertebral maturation stages estimate skeletal maturity for timing treatment.

Obturators: a surgical obturator is placed at surgery, a provisional obturator during healing, and a definitive obturator after healing; the bulb seals the defect and restores speech and swallowing.

Facial prostheses: silicone elastomers (platinum-cured) are used for auricular, nasal, and orbital prostheses; retention by adhesives, eyeglasses, or implants; color matching and margins are critical.

Implant framework: a screw-retained framework requires passive fit; misfit can cause screw loosening, fracture, or bone loss; verification with a one-piece cast or sectioned and soldered framework.

Abutment selection: internal and external connections; platform switching reduces crestal bone loss; abutment height and angulation determine retention and path of insertion.

Attachment systems: stud attachments (ball, locator) provide retention for overdentures; bar attachments splint implants; magnets provide minimal retention and are used in selected cases.

Implant loading: immediate loading requires adequate primary stability (insertion torque ≥ 30-35 Ncm); delayed loading allows osseointegration; splinting distributes load.

Obturator design: hollow bulb reduces weight; the defect side must be extended to seal; the remaining teeth and implants provide support, retention, and stability.

Maxillofacial materials: silicone, acrylic resin, and polyurethane; silicone is flexible and lifelike but degrades with UV and requires replacement; acrylic is rigid and durable but less lifelike.

Disinfection: impressions and prostheses should be disinfected before laboratory handling; sodium hypochlorite, glutaraldehyde, and iodophors are common; follow manufacturer contact times.

Sterilization: autoclave at 121°C for 15-20 min or 134°C for 3-4 min; dry heat at 160°C for 2 h; chemical vapor; biological indicators (Geobacillus stearothermophilus for steam) verify sterilization.

Waste handling: sharps in puncture-resistant containers; regulated medical waste separated from general waste; amalgam waste recycled; follow local regulations.

Occupational safety: eye protection, masks, gloves, and gowns; ventilation for monomer and dust; noise control; ergonomic design to prevent musculoskeletal disorders.

Laboratory management: quality assurance includes calibration of equipment, documentation, and traceability; equipment maintenance schedules for articulators, casting machines, and ovens.

Cross-contamination: use separate clean and dirty areas; label cases; transport in sealed containers; hand hygiene before and after handling cases.

Chemical safety: material safety data sheets (MSDS) for all chemicals; proper storage and labeling; ventilation for volatile materials; spill kits available.