Esthetics in Tooth Preparation

7/28/2019 Esthetics in Tooth Preparation

1/25


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


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.


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.


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.


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.


7/25

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


8/25


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


10/25

Obviously, if the destruction is part of a fixedpartial denture ; the need for connectors willmake this impossible.


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


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 .


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.


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.


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.


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.


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.


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.


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


20/25


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.


22/25


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.


24/25


25/25

Documents

Esthetics in Tooth Preparation