RSD 814 - Exam 1

• The dental mirror is used for indirect vision of tooth surfaces or intraoral structures that can't be seen directly.
• The dental mirror is used to retract and hold soft tissues.
• The dental mirror reflects light from extraoral sources for indirect illumination.
• The dental mirror reflects light through intraoral structures for transillumination.
• Improved indirect vision skills can prevent rounded shoulders in dental hygienists, promote balanced posture, and reduce back/neck flexion.
• Indirect vision preclinical training positively affects student working postures.

Class I Preparations on Maxillary Premolars

• The No. 245 bur should not converge on proximal walls.
• Proximal walls should be parallel or divergent.

Class I Preparation of Maxillary Molars

• Preserve the oblique ridge to maintain the tooth's integrity.

Basics of Facial Esthetics & Smile Design

• Facially Generated Treatment Planning involves dento-facial, dento-labial, dento-gingival, and dental analyses.
• Dento-labial Analysis considers incisal edge position, incisal display at rest, smile line, and buccal corridor.
• The "Rule of Thirds" divides the face into equal thirds: hairline to glabela, glabela to soft tissue subnasale, and subnasale to chin base.
• Average lip length for women is 20-22 mm; for men, it is 24-26 mm.
• Overly mobile lips that reveal significant soft tissue may be less esthetic.
• Ideally, facial and dental midlines should coincide.
• Central incisor proportion should be 80-85% length:width and mirror each other.
• Consider gingival margins, axial inclinations, and contacts when planning.
• Triangular vs. square central incisor tooth forms must be factored in.

Esthetic Considerations

• Esthetic priorities include smile line, incisal profile, incisal length, central incisor proportion, tooth-to-tooth proportion, gingival outline, and desire for fullness.
• Aesthetic factors: tooth size, tooth form, contact length, papilla location, gingival zenith, maxillary/mandibular tooth display, smile line, lip length/mobility, VDO, facial height, age, and gender.
• Dento-Facial Analysis: concave vs. convex facial profiles should be assessed.
• Lab communication to include: "Please fabricate crown A2 with incisal translucency/halo, saturation of cervical third, demineralization/fluorosis spots, surface texture/gloss for delivery" is recommended.
• Color is Light.

Light Behavior

• Transmission: light passes through an object.
• Reflection: light bounces off an object at an angle unlike its entry point.
• Color Characteristics: Hue, Chroma, Value should also be determined.

Color Characteristics

• Hue is the color tone
• Chroma is saturation
• Value is relative lightness/darkness of color
• Shade selection should consider each of these, along with contrast & brightness.
• L* Scale: light vs. dark - 100 is white & 0 is black
• B* Scale: yellow vs. blue - positive # indicates yellow & negative # indicates blue
• A* Scale: red vs. green - positive # indicated red & negative # indicates green
• Shade Guides: A (reddish-brown), B (reddish-yellow), C (grayish), D (reddish-grayish)
• Shade Selection Tips: be careful with dehydration, shade tab in same plane, free of saliva or plaque, select a stump tab, think about which material you'll use.

Class II Maxillary Preps & Rests

• Used for posterior interproximal lesions
• Patients may experience sensitivity to cold/heat as they advance
• Secondary caries: may occur around existing restorations

Restorative Materials

• Choose restorative materials based on caries risk assessment, ability to isolate, occlusion, lesion size, and patient preference.
• Composite resin restorative materials have improved and show public interest
• Polymerization shrinkage is its main disadvantage so use proper technique!
• Must be used with contemporary bonding systems
• Excellent isolation is critical

Composite Longevity

• Longevity of posterior composite multi-surface restorations are comparable to amalgam.
• Composite & amalgam perform similarly in molars; 3-surface restorations are a challenge for both.

Initial Clinical Considerations

• Assess the outline form & determine if enamel periphery exists
• Ascertain if the root surface is involved
• Identify heavy contacts during assessment of the occlusion
• High or low caries risk?
• Finally preoperative wedging has to be considered

Class 2 Considerations

• Base decisions on occlusal caries compromising marginal ridges vs. proximal caries.
• Gingival to contact means you step down
• Marginal ridge is thin & compromised or no proximal caries entails you include the proximal surface, no step down

Proximal Extensions

• Box only (slot) preparation – only proximal is carious
• Occlusal & Proximal preparation – occlusal caries compromising marginal ridges or occlusal & proximal caries (step down or not)
• Tunnel preparation – only proximal is carious; enter tooth from facial OR lingual

Composite Preparation

• Small & conservative: proximal caries only, no occlusal caries, enter occlusal to access proximal
• Objectives - remove caries/defect conservatively
• It's not essential to break buccal, lingual, or gingival contacts.
• Pulpal & axial depths dictated by depth of lesion creating convenience form
• Remove enamel spurs (unsupported enamel)
• Preparation is initiated just inside it with a small round bur
• May be extended with a No. 330 bur – proximal surface is left intact.
• Fracture and remove the thinned enamel using a spoon excavator or hatchet.
• Occlusal pits and fissures that aren't carious may be treated with sealants.
• Deeply stained or demineralized fissures may be opened with a small bur or air abrasion.

Moderate proximal caries

• Def: Caries diagnosis in the occlusal & proximal surface that is gingival to the contact point
• Results in Step-Down at the proximal (proximal box) because of location of the caries

Preparation for Proximal contacts

• When found immediately gingival to the proximal contact, consider the extent of caries & existing restoration.

Facial & Lingual Margins

• Design the facial/lingual margins at 90° or obtuse
• There is no need for clearance with the adjacent tooth! This makes a step-down likely
• Occlusal cavosurface margins should be 90°, with walls exposing enamel rods
• Bevels on the occlusal surface may lead to thin composite where there is heavy contact.
• Bevels also make achieving a good finish more difficult.
• Use smaller instruments such as a bur or hand instrument to complete them
• Avoid undermined facial & lingual proximal margins
• Proximal extension: Preserve enamel while removing decayed areas
• Gingival extension: use margin trimmer to smooth the gingival floor
• 90° exit angles for root surfaces are recommended
• Inverse or internal bevels may be used to conserve enamel for bonding

Preparation Extension

• Maintain enamel when possible, using a glass ionomer when enamel is absent.

The Restoration

• Place the matrix, etch and apply adhesive, insert composite in increments, remove matrix, finish composite, check occlusion, polish composite, floss.

Matrix Selection

• Matrix matrix and contour are important
• Tofflemire matrix: has ultrathin, burnishable matrix bands for extensive preparations or those needing both proximal surfaces restored
• Matrix must extend 1 mm below the gingival margin and occlusally above the marginal ridge
• You must use a wedge, it:
  • Holds matrix in place
  • Provides slight separation of the teeth
  • Prevents gingival overhang of composite material
  • Also, burnish with a hand instrument and smooth the matrix in place

Oblique Incremental

• Place incremental layers of composite to restore box area
• Each increment should be 1-2 mm thick and fully cured
• When placing you should avoid connecting opposite walls of the preparation
• Marginal ridge should avoid too many increments which leads it to increase tooth deformation

Centripetal Oblique

• Build the wall as enamel shell before the matrix
• Transform class II preparations to class I using with oblique layering after a 2-year follow up
• Achieves better contour w/less use of rotary instruments

Bonded Base/Open Sandwich

• If there is no enamel for bonding on the gingival floor place a GI layer and use a matrix.
• The GI layer can be etched and primed
• Clinical outcomes showed little difference in restorations failure

Class II composites

• 3-year study of performance w/adhesive only vs sandwich approach showing the sandwich approach had less gingival margin demineralization
• When curing composite increment, direct laser toward area
• Technique tips, composite may be lightly heated to improve viscosity

Class II Composites

• 12 Blade to smooth carves and remove flash interproximally
• Oxide disk to contour and resin; available in points to polish the occlusal
• Fine Diamond - and multi-fluted carbide can be used to refine the occlusal

Adjacent Restorations/Preparations

• Prepare the largest lesion first for access allowing conservation
• Restore the smallest prep first

Reverse 'S' Curve:

• Conserves as much of the facial cusp as possible.
• Limits the extension into the mesiofacial cusp to create a 90° mesiofacial margin.
• Minimizes or eliminates the lingual reverse curve, to the interproximal contact of the tooth.

Pulpal Considerations

For tooth restoration, steps in tooth preparation include:

• Initial depth & outline form
• Primary & secondary resistance forms
• Removal of defective restoration/soft dentin

Pulp Protection

• Pulp protection is the step to finalize the preparation for the final restorative method
• This is to protect pulp, reduce post-operative sensitivity, and seal pulp

Restoration Options

• Sealers: provide a protective coating for freshly cut tooth structure (ie. Adhese Universal)
• Liners: placed with a minimal thickness ( < 0.5 mm), and provide therapeutic benefit (ie.fluoride release, dentinal heal, and act against bacteria). Liners reduce post-op sensitivity, margin seals, and pulp protector.
• Bases: used as dentin replacement material, allowing for less bulk of restoration or blocking out undercuts for indirect restorations, and used along with composite.

Sealers

• Bonding provides retention & prevents leakage around enamel margins of restorations
• Bonding to enamel is a relatively simple process, easier with etching
• Dentin adhesion relies primarily on adhesive penetration of monomers into the network of collagen fibers and can be achieved w/universal adhesives
• Desensitizers occludes the dentinal tubules by precipitating plasma proteins; glutaraldehyde crosses-link proteins

• Process: etch, sealer, adhesive, restoration

Deep Dentin

• Porous, deeper carries little protection from instrumentation, materials, thermal changes, and toxins
• Studies find the deeper the dentin is more susceptible

Dentin Thickness

• More RDTs show an exponential benefit so use the liner when you have to
• As you heal deeper the composition of those materials has potential to trigger an immune response

Liner Usage Criteria

• RDT greater than 2 mm = no liner needed
• RDT less than 2 mm = consider a liner
• RDT less than 1 mm = liner needed
• Post-op sensitivity and the type of bonding agents could cause sensitivity due to increase in cavity depth and the agents

Liners

Reduce post-op sensitivity, seal dentin margins, protect the pulp – RMGI is most commonly used w/ a thickness of 0.5 mm Therapeutic benefits of RMGI: light activated & has a Fl release W/pulp exposure you use mineral trioxide aggregate (MTA), antibacterial/biocompatible/high pH/good seal but high solubility that req's more material covering.

Bases usage

• Acts as a thermal or chemical barrier to block out undercuts
• Composites often require bonding for pulp and the thickness >.5mm
• Examples: Most common Base is GI or RMGI like Fuji II LC
• Use these with metallic restorations
• Amalgam workflow requires 2mm dimension of bulk or amalgam prep must me min depth is 1.5 mm
• Composite workflow liner and consider thickness and enamel for bonding in ext. lesions
• Studies show RMGI has the cavity liner show the least leakage and use may implement a band technique
• Sandwich: Consider potential for bonded base=reduced leakage and gap formation (caries) in open sandwich where you use RMGI 1st

Class Ionomer Cements

• For metallic restorative materials: need 2 mm between the pulp and restoration. Composite acts as a thermal insulator and doesn't require the same bulk of material between restoration and pulp.
• If excavation of caries extends to within 1.0 mm of the pulp, a liner is selected to cover the deepest area of dentin.
• "Cements" can be restorative OR lute agents that don't have direct bonding
• Only dental material w/true bond to a w/o adhesive that is from fluoride release w/niche apps in restorative dentistry
• Essential hydro ingredients also polymer chains is not well understood
• 2 types of GI we use @ukcd in Auto cure or Sets
• Conventional glass ionomer material Equia Forte doesn't have light curing

Equia forte material

• Can be used in Class 1,2 5 and great use around the gums/ roots w/ high risk patients
• The glass hybrid innovation is achieved through the introduction of ultrafine, highly reactive glass particles, dispersed within the conventional Gl structure
• *NOT viable for core builds up, as it's too weak
• Extensive retention preparations aren’t needed during procedure
• You should start finishings minutes prior to the end mix

Fuji materials

• Less depth of cure than resin composites
• Used for pulp capping when allergic but has a low cure depth
• For dentin prep make sure to clean dentin without removing which has optional steps for preparation
• GI materials function &re-release fluoride reservoir that has 24 burst
• Acidic habitat can cause GI loss
• Keep balanced H2O to protect from desiccation/ prevent isolate from desecration
• Don’t invert your material around restoration to prevent harm and is corrosion free
• 85% shows long term success and esthetic can be cervical w/RMGI

ART

• atraumatic restoration has hand only instrument, and caries is w/ gloved hands
• This allows for an opportunity to seal and reduce risk factor during early stages/ high risk pts

Materials

• Gi shows better esthetics than most materials however seal and strength are needed for longer survival
• If located In the neck then it looks best
• Overview: This may be good and water tolerable but if the h20 isn’t balanced it can dry product out