Operative: Class Vs and Sandwich Techniques

CLASS V steps (summarized)

Access → 330 FG

Peripheral cavity removal w/ round #2

Round #6 or spoon excavator used for pulpal/axial walls

*** using a larger bur  = removes less tissue 

Outline form → 330 

Caries removal is first done @ periphery and along DEJ 

• do until we see clean DEJ! 

Explorer used for → assessment of surface texture only 

• be careful in deeper areas to not damage pulp 


• do not use in axial area

When material has set, excess is shaved away w/ → No. 12 surgical blade 

• Contoruing/finishing = use hand instruments as much as possible while preserving smooth surface 


• If you use rotary instruments = DO NOT DEHYRDRATE SURFACE OF RESTO 

Goals of Caries Removal in the Prep:

• Axial wall → selective removal to FIRM DENTIN


• Periphery walls (O,M,G,D) → Hard dentin DEJ 


• Occlusal and Gingival walls → parallel to slightly divergent 


• M and D walls → divergent 


• Margin (Butt joint margin) → NO bevels. Smooth margins and walls. 

Sandwich Tech Lecture

Full thickness bevel → all the way to DEJ 

Partial thickness = not entire enamel

GI or RMGI

• Dentin replacement = GIs similar thermal conductivity and coefficient of thermal expansion


• Fl release= takes place at setting rxn, the initial release is high and decreases with time


• Chemical bonding to dentin 

Why RMGI?

1. Superior mechanical properties than GI


2. Can be contoured and polished v similar to RBC 


3. Stronger in acidic environment = don’t want it to erode easily 


4. Conventional GI = poor maintenance of anatomical form 


5. Conventional GI suffers rapid surface degradation 


6. Conventional GI doesn’t present optimal esthetics = not easy to polish 

Sandwich technique = layers of GI (conventional or RM) between dentin and perm restorative material (resin composite or amalgam) 

Overall Indications of Close Sammy Technique

1. Pulp protection




1. selective Caries removal


2. preparation extends very close to pulp


3. Fl-release promotes affected dentin remin




2. Remaining enamel at the gingival margin




1. better bonding with composite than GI (GI on composite will decrease mech. Properties of resto) 


2. GI best at bonding with dentin

Anterior Resto indications for CLOSE SAMMY

• veneered w/ composite to: 

1. Enhance esthetics 


2. enhance polishability 


3. increase abrasion resistance 

Posterior Restos for CLOSE SAMMY

• veneered w/ composite or Amalgam for increased fracture and wear resistance 

Open Sammy Technique

• layering of two directly placed materials where both exposed to saliva 


• AKA: Bonded-base technique (summit) 


• helps w/ fl- release to oral environment 

Open Sammy indications:

1. Restoration of deep cervical lesions w/ dentin or cementum margins (severely damaged teeth w/ no enamel on the margins)


2. Need material that contains Fl to reduce potential recurrent Caries ( = high risk pts)


3. The selective material for open sandwich technique is RMGI

Closed Sammy Technique 

• layering of two directly placed materials, one covering the other


• Dentin is covered by RMGI/GI 


• GI/RMGI = completely covered by the overlaying Resto (RC or amalgam)


• Liner/base = GI is placed internally (on dentin) and completely surrounded with a second material (Amalgam or RBC)


• NO GI is exposed to saliva 

Closed Sandwich Technique Steps 

1. Prep → NO BEVEL. Butt joint only 


2. Rinse and dry → DON’T DESICATE, leave dentin moist (GIC needs water for Rxn) 


3. Apply GI/RMGI → place GI over pulpal and/or axial wall 


4. Check margins → do not place GI over any margins/on enamel 


5. Etch and rinse


6. Prime → Prime remaining exposed dentin- no primer on GI 


7. Final Resto 

Open Sandwich Steps

1. Prep → NO BEVEL on cementum. Butt joint only. 


2. Rinse and dry


3. Apply RMGI → place RMGI over PULPAL/AXIAL walls 


4. Light Cure


5. Etch and rinse 


6. Prime


7. Final Resto 

Technique

Indication

Contact w/ saliva?

Surfaces

Material

Closed sammy

Pulp protection (enamel on margins) 

No

Axial and pulpal walls

GI or RMGI

Open sammy

Deep cervical lesions w/ dentin or cementum margins 

Yes = Fl- release to oral einvronemnt 

ANY (except surfaces under occlusal forces) 

RMGI