Class I Prep Variations in Medicine Terms & Definitions

class 1 outline form determinants

1. anatomy

2. extent of enamel involvement by caries

3. lateral spread of caries along the DEJ

what is not a determinant of class 1 outline form?

depth of caries

max anterior class 1 prep outline form follows

lingual pit + defect (lots of variation in lateral incisors)

anterior class 1 prep outline form shape, where is apex?

rounded triangular

rounded triangle max anterior class 1 prep outline form apex is located ___ and sides located ___

apex = in pit

sides = mesial/distal marginal ridges

anterior class 1 prep outline form wall angulation

parallel or slightly convergent

anterior class 1 prep axial wall should be ___ to external tooth surface to avoid ___: how?

parallel

pulpal exposure

Orient bur perpendicular to lingual surface, not parallel to long axis of tooth

anterior class 1 prep outline form total depth

1.5mm

any deeper may jeopardize pulp

what tooth has the largest occlusal table of all teeth?

max 1st molar

do max and mand molars have the same anatomy?

no... therefore different prep techniques are needed

oblique ridge molar

preserve this on 1st max molars!

max first molar: occlusolingual

man first molar: occlusofacial

for max molars class 1 preps, to preserve oblique ridge, marginal ridges, and cusps, extend ___ into all cusps

1/4 way up

what is the only part of a class 1 max prep that is extended 1/3-1/2 (instead of 1/4)?

buccal developmental groove

max molars mesial/ central pit caries characteristics (other than extensions + MMR/oblique preservation)

- "butterfly" appearance

- include all of central developmental groove (center to mesial pit)

- include mesial triangular fossa

max molars distal pit caries characteristics (except extensions + DMR/oblique preservation)

- include distal pit and affected portion of groove

- cavosurface parallel

class 1 max molar lingual caries outline form shape + locations

shape = elliptical

locations = lingual pit

lingual portion of max OL prep should terminate

just gingival to lingual groove

should mesial/central and distal outline forms be connected for maxillary molars?

no

should distal and lingual outline forms be connected for maxillary molars?

yes

why should distal and lingual outline forms be connected for maxillary molars?

because the groove that connects them is involved

OL class 1 is indicated when what 3 things connect?

1. lingual fissure

2. distal oblique fissure

3. distal pit

maxillary OL class 1 preps must

respect the oblique ridge

isthmus definition for class 1 OL prep

mesiodistal width of lingual extension

*essentially the straight part of the prep that connects the distal and lingual pits

isthmus width of lingual extension is always ___ unless you need to ___

1mm

remove caries/ undermined enamel

should prep include oblique ridge, buccal cusp, or fissure if some have to be included? why?

remove oblique ridge and buccal cusp if needed (preserve fissure + be slightly mesial to distal oblique fissure)

removed fissure = weakens DL cusp (want to avoid)

aka be more mesial rather than more distal w/ prep

occlusal portion of class 1 OL prep has a slight ___ inclination to conserve ___ which supports the ___

distal

dentin support

distal marginal ridge

O portion of class 1 max OL mesial, distal, and buccal walls

buccal = convergent

mesial = convergent

distal = divergent

L portion of class 1 max OL mesial and distal walls

mesial = convergent

distal = convergent

which wall is different between L and O portion of OL max molar prep? how so?

distal wall

L = convergent

O = divergent

prep design max molar OL characteristics

- smooth walls

- mesial + buccal walls converge

- distal wall diverges occlusally (rest is convergent)

- isthmus width 1mm

isthmus should ___mm wide and be able to fit the ___ but should be as conservative as possible

1mm

nib of a condenser

inclination for class 1 max OL groove prep

occlusal distal inclination

occlusal portion of OL max molar prep should be more ___ to the distal pit (__:__ not __:__)

mesial

70:30 (ideal)

50:50 (avoid)

OL max molar prep depth at distal pit

1.5mm (1.75-2mm from walls of prep)

OL max molar prep axial wall depth

1.0mm (width of isthmus on lingual surface)

lingual portion of OL max molar bur angulation and tip placement

bur = parallel to lingual surface or slight distal tilt

tip = at gingival end of lingual fissure

lingual portion of OL max molar axial wall follows the contour of

lingual surface of tooth

is the lingual portion of OL max molar axial wall concave or convex?

convex

lingual portion of OL max molar mesial and distal walls are

convergent

lingual portion of OL max molar has ___ axiopulpal line angle

rounded

lingual floor during an OL prep must follow ___ in order to ___

cuspal incline

maintain proper pulpal floor depth

class 1 proper pulpal depth

1.5mm (0.5mm into dentin)

class 1 OL prep pulpal vs axial depth

pulpal depth = occlusal depth = 1.5mm

axial depth = lingual width = 1.0mm

what dictates differences in outline form/ extension for max OL preps?

anatomy

what should always be preserved with max molar OL preps?

oblique ridge

if caries are present in mesial and distal occlusal pits but the oblique ridge in unaffected

do two DISTINCT prep (not connected) to preserve the oblique ridge

buccal portion of OB class 1 mand molars prep will be ___ shaped and should include the ___

round or elliptical

buccal pit

class 1 OB mand molars should combine ___ because ___

occlusal and buccal pit preparations

groove between them is affected

buccal portion of mand molar OB class 1 prep walls

parallel or slightly converging

what parts of OB prep mand molar need to be self-retentive?

BOTH O and B portions

for mand molar OB prep walls, you must ___ or ___ the axio-pulpal line angle

round

bevel

is step from occlusal to buccal in mand molars or occlusal to lingual in max molars more prominent?

occlusal to lingual in max molars

only extend ___ of oblique ridge height to preserve it

¼

only extend ___ of MB + ML cusps and marginal ridge to preserve it

¼

extend ___ of buccal developmental groove

⅓-½

mesial and distal cavosurface should be ___ to their respective ridge in an OL max prep

parallel

lingual portion of OL prep has retention mainly from ___ but ___ can be placed if needed

frictional resistance

retention grooves in lingual extension