Esthetics in Tooth Preparation
-
Upload
aishwarya-patel -
Category
Documents
-
view
237 -
download
4
Transcript of Esthetics in Tooth Preparation
-
7/28/2019 Esthetics in Tooth Preparation
1/25
-
7/28/2019 Esthetics in Tooth Preparation
2/25
The restorative dentist should develop skills indetermining the esthetics expectations of thepatient.
Patient prefer their dental restorative to look asnatural a possible.
However, esthetic consideration are notpursued at the expense of a patients long-termoral health or functional
-
7/28/2019 Esthetics in Tooth Preparation
3/25
At the initial examination it is important tomake a full assessment at the appearance ofeach patient, nothing which areas of whichteeth show during smiling, talking andlaughing.
The patients esthetic requirements must be
discussed and related to oral hygiene needsand the potential for disease.
The final decision regarding an appropriaterestoration can then be made with fullcooperation and informed consent of thepatient.
-
7/28/2019 Esthetics in Tooth Preparation
4/25
Usually poor appearance is due to insufficientporcelain thickness
In addition , the labial margin of metal
ceramic crown is not always accurately placed To correct all these deficiencies , certain
principles are recommended during toothpreparation.
-
7/28/2019 Esthetics in Tooth Preparation
5/25
Adequate thickness of porcelain is needed tocreate a sense of color depth and translucency
Adequate reduction sufficient bulk ofporcelain appearance and metal for strength
Minimum reduction of 1.5 mm is required
Shade problems incisal and cervical 3rd ofrestoration (here direct light reflection from the
opaque layer can make the restoration appearvery noticeable.
-
7/28/2019 Esthetics in Tooth Preparation
6/25
Opaque porcelain generally have a differentshade from body porcelain , they often need tobe modified with special stains in these areas.
With very thin teeth like mandibular incisors.
-
7/28/2019 Esthetics in Tooth Preparation
7/25
The incisal edge of a metal-ceramic restorationhas no metal backing and can be made with atranslucent similar to that of natural tooth
structure. An incisal reduction at 2 mm is recommended
for good esthetic.
Excessive incisal reduction must be avoidedbecause it reduces resistance and retentionform of the preparation
-
7/28/2019 Esthetics in Tooth Preparation
8/25
-
7/28/2019 Esthetics in Tooth Preparation
9/25
The extent of proximal reduction is contingenton exact predetermination of the location at themetal ceramic junction in the completed
restoration. The proximal structure of anterior teeth will
look must natural if they are restore as theincisal edges ; without metal this will allow
some light to pass through the restoration in amanner similar to what occurs on a naturalteeth
-
7/28/2019 Esthetics in Tooth Preparation
10/25
Obviously, if the destruction is part of a fixedpartial denture ; the need for connectors willmake this impossible.
-
7/28/2019 Esthetics in Tooth Preparation
11/25
Supragingival margin placement has manybiologic advantages
The restorations are easier to prepare properly
and easier to keep clean. Nevertheless sub gingival margins may be
indicated for esthetic reasons , particularlywhen the patients has a high lip line and the
use of metal collar labial margin iscontemplated .
The patients smile is observed as a part of ainitial examination
-
7/28/2019 Esthetics in Tooth Preparation
12/25
it is important to record which teeth andwhich part of each tooth are exposed .
Patients with a high lip line , which exposesconsiderable gingival tissue, present thegreatest problem if complete crowns areneeded.
Where the tooth structure is not discoloredrestored can be with a metal-ceramicrestoration having a super gingival porcelainlabial margin sometimes called a collarless
design .
-
7/28/2019 Esthetics in Tooth Preparation
13/25
If the patents has a low lip line , a metalsupragingival collar may be placed because themetal is not seen during noraml function.
Metal margins genrally have a more accuratefit then porcelain margins.
However it can not be assumed that patient
will be happy with a supragingival metal collarjust because metal is not visible during normalfunction .
Some patient have reservation about exposedmetal and the advantages of suchsupragingival margins must be carefullyexplained before treatment.
-
7/28/2019 Esthetics in Tooth Preparation
14/25
Metal collars can be hidden below the gingivalcrest, although there will be some discoloration ifthe gingival tissue is thin.
Successful margin placement within the gingivalsulcus requires care to ensure inflammationand/or recession with resulting metal exposure,are avoided or minimize .
The periodontium must be healthy before the toothis prepared if periodontal surgery is needed thesecular space should not be eliminated completelyrather, a post completely surgical depth of about2mm should be the objective sufficient time shouldbe allowed after surgery for periodontal tissue forstabilized.
-
7/28/2019 Esthetics in Tooth Preparation
15/25
wise found that the gingival crest does notstabilized until 20 weeks after surgery.
Margin should be placed so far apically thatthey encroach on the attachment ; extension towithin 1mm of alveolar crest will lead to bonerestoration .
The margin should followed the contour of thefree gingival been further apical in the middleof the tooth and further incisal inapproximately .
A common error is prepared a tooth so marginlives almost in one plane with exposure of thecollar labially and irreversible loss of bone andpapilla proximally.
-
7/28/2019 Esthetics in Tooth Preparation
16/25
Whenever possible, accomplishment of an estheticallyacceptable result without the use of metal-ceramiccrown is preferred, not only because tooth structure isconserved but also because no restorative material canapproach the appearance of intact tooth enamel
esthetic partial coverage restorations depend onaccurate placement of the potentially visible facialunder proximal margins.
Understandably, may patients will not readily accept avisible display of metal if a partial converge
restoration is poorly prepared, the patient maydemand that it be replaced by a metal ceramic crownand the result will be unnecessary loss of toothstructure and greater potential for tissue damage.
-
7/28/2019 Esthetics in Tooth Preparation
17/25
Placement of the proximal margins ( particularly themesial generally more visible margin ) is critical to theesthetic result of a partial-converge restoration.
The rule here is to place margin just buccal to the
proximal contact area, where metal would be hiddenby the distal line angle of the neighboring tooth.
Tooth preparation angulations is critical and shouldnormally follow the long axis of posterior teeth andincisal 2/3rd of the facial surface of anterior.
It a buccal or lingual tilt is given to the toothpreparation, metal may be visible.
-
7/28/2019 Esthetics in Tooth Preparation
18/25
The distal margin of posterior partial coveragerestoration is less visible then the mesialmargin. Often in this area it is advantageous toextend the preparation further beyond thecontact point for easier preparation andfinishing of the restoration and better access for
oral hygiene.
-
7/28/2019 Esthetics in Tooth Preparation
19/25
Facial margin of maxillary partial coveragerestoration should be extended just beyond theocclusofacial line angle.
A short bevel is needed to prevent enamel
chipping. a chamfer can be placed whereappearance is less important because this willprovide better bulk of metal for strength.
If the buccal margin of metal is correctly saved , it
will not reflect light to an observer. As a result the tooth will appear to be merely a
little shorter then normal and not as though itsbuccal cusp is outlined in metal
-
7/28/2019 Esthetics in Tooth Preparation
20/25
-
7/28/2019 Esthetics in Tooth Preparation
21/25
The buccal margin is skillfully placed followingthe original cuspal contour, the final restorationwill have an acceptable appearance .
When mandibular partial cast crowns are made,metal display is unavoidable because the occlusalsurface of mandibular teeth can be seen duringspeech .
A chamfer rather then the bevel is recommendedfor the buccal margin because it provides a greaterbulk of metal around the highly stressed centriccusp .
If the appearnce of metal is unacceptable to thepatients, a metal ceramic restoration withporcelain coverage, on the occlusal surface can bemade.
-
7/28/2019 Esthetics in Tooth Preparation
22/25
-
7/28/2019 Esthetics in Tooth Preparation
23/25
Anterior partial coverage restoration can befabricated to show no metal, but, there
preparation requires considerable care . The facial margin is just extended beyond
highest contour of the incisal edge but not quiteto the incisolabial line angle .
Here the metal will protect the tooth fromchipping but will not be visible.
-
7/28/2019 Esthetics in Tooth Preparation
24/25
-
7/28/2019 Esthetics in Tooth Preparation
25/25