cons sheet # 5 - Amneh shdefat

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cons sheet # 5 - Amneh shdefat

Post by Shadi Jarrar on 16/3/2011, 3:04 am

بسم الله الرحمن الرحيم

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cos#5.JUDe.doc
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بسم الله الرحمن الرحيم
Cons. Sheet #5 .
Date of lec. 7.3.2011
Done by : amnah shdifat


Treatment of grossly carious teeth
We take about class I & class II amalgam cavity preparation and filling .
When we have one surface , 2 surfaces or even 3 surfaces we still conceder the cavity is simple cavity .
May be we need to replace cusps and walls ( when we have missing cusps or multiple missing walls , 2 or 3 walls missing ) this is complex filling .

Complex posterior restorations are used to replace missing tooth structure of teeth that :
1. Have fracture ( when tooth fracture we should replace the missing cusps or walls ) .
2. Severely involved with caries .
3. Existing of restorative material (in case of recurrent caries we should remove restorative material and caries and clean the tooth then restore it again ).

Problems encountered with large restoration :
1. Most of occlusal contact will be restored with restorative material .( if the cusps or marginal ridges are lost ).
2. Extension might be toward the root surface .(when we have subgingival caries ).
3. The area to be restored will be difficult to isolate .( amalgam need isolation in lesser amount than does glass ionomer & composite ).

Differences between ordinary class II & extensive cavity :
• Some or all the cusps may need to be capped . → if we don’t capped the cusps , it would be fracture under the force of occlusion .
• Extensions in all direction need to be greater .
• More secondary retentive feature will be needed. → coves & lock & groove , all considered as retentive means in addition to occlusal extension or dovetail .
• More resistance form feature will be used .

Stage for restoring post. Large cavity :
Same stage for restoring any cavity
• Preoperative assessment
Clinical diagnosis of patient , take radiographs , do vitality test ….
• Caries removal .
• Designing the restoration.
If we have retention or resistant , can withstand the occlusal force .
• Choice of restorative material .
You should put in minds what is the restorative material will you use it in filling ( amalgam ,composite , to a lesser extends glass ionomer) before you do the outline form .


Stage 1 : Preoperative assessment

A. Clinical examination .
B. Extent of caries and existing of restorative material & its relation with gingival margin ( supramargin or submargin ).
So we adjust the gingival margin to be able to see the margins of the restoration & the contour .
e.g : if we have class II cavity preparation and the caries extent subgingival , then we should go subgingival and remove the caries and should expose the margin of the filling by periosurgery or electrosurgery to do proper filling ( not over hang or under filled ).
The matrix band can't enter subgingivally because it stops in gingival margin ( labiolingually) so we do periosurgery .
Periosurgery : cutting of part of the gingival , so the gingival margin expose to oral cavity which allows perfect isolation , contouring …etc .
C. Assessment of the pulp vitality .
Vitality testing : assessment of a vital or necrotic pulp .
e.g : patient has huge cavity in his tooth and he say there is no pain , then we have 2 possibility :
1. The patient has chronic caries( no pain ) in his tooth and the pulp is vital .
2.pulp are necrotic → caries involve the pulp .
D. Examination of occlusion in centric and lateral excursion → to determine contact so as to restore the contact properly .( should examine the occlusion in centric occlusion and during movement ,lateral right , left lateral , forward movement , this is very important because we replace cusps, groove, wide area.
To do good filling we should know :
1. Point of contact on cusps.
2. The height of cusps .
3. The distance between the cusps.
D. Radiograph by ( bitewing , periapical ).
Bitewing RG:
1. To detect proximal caries ( clinically if marginal ridge intact ,we can NOT detect proximal caries.
2. To detect extension of caries & how much caries or restoration is close to the pulp .
3. Should be routine for post. teeth .
Periapical RG:
( it has a high magnification than bitewing and it's NOT good idea about extension of caries ).
1. To detect periapical lesion ( necrotic tooth)
2. Periodontal problems
3. Bone level & its relation to the apex .
4. Should be routine for ant. teeth .

Stage 2: caries removal .

1. Old restoration should be removing .
2. Access to carious dentine .( first we remove the old restoration then start remove the caries or under mind enamel to improve the visibility , to avoid the exposure and increase the area ).
Very important : we shouldn’t be conservative 3la 7sab el visibility . Don’t work in small excess to avoid the pulp exposures , at the same time don’t extend the access to be traumatic cutting .
3. Cleaning dentino-enamel junction .
4. Remove the under mind enamel .
5. Remove of caries from the pulpal wall .
We start removing the caries in enamel then clean the DEJ ( we know the caries start small in enamel when it reaches the dentin , it spread laterally so to clean the cavity we should clean all the DEJ because the caries in DEJ is in wide area than caries in enamel or in dentin .
the exposure to pulp is might be un avoidable because the caries is deep . if we have clean walls ,cavity ,and the pulp is exposure when we drilling , we can treat it by pulp capping ( no contamination to pulp , pulp is clean ) and the success rate is high.
On the other hand ,if we have un clean walls ,cavity ( we have bacteria ) if the pulp is exposure sure we contaminate the pulp by bacteria ,then if we clean the cavity and do pulp capping the success rate will be more less so we should do access cavity ( endo).
In case of pulp exposure we can repair it by :
1.Direct pulp capping by calcium hydroxide ( mechanical exposure or carious exposure ).
2. in direct pulp capping .
3. Root canal treatment ( RCT) in case of nonvital pulp or contaminated pulp or the exposure site is wide .


Stage 3 : designing the restoration .

• Design is initially indicated by the previously existing restorations .
• The relation of the floor of the cavity to the gingival margin ( place modified by periosurgery ).

Stage 4 :choice of the restorative material .
{ type of the restorative material to be used }
- Depend on the amount of remaining tooth structure present
- Not always the direct restoration is the best solution .
- Usually we go to the indirect restoration because we have to cap weak remaining tooth in order to withstand the occlusal forces .
Treatment options for grossly carious teeth :
Direct restoration :
1. Amalgam ( bonded ,pin ,retained ,core ) .
2. Composite ( restorative material or foundation under indirect restoration ) .
Indirect restoration :
1. Indirect composite
2. Inlays 3. Onlays 4.3 ⁄ 4 Crowns 5. Crowns.

Amalgam :
Advantages :
1. Easy to use
2. High compression strength
3. High wear resistance
4. Proven large term clinical performance (at least the amalgam has been used for 50 years or more ).
Disadvantages :
1. NOT esthetic.
2. Require a retentive tooth preparation .
3. Dose NOT seal or strength tooth structure ( it just fills the gap).

Amalgam may be used as :
1. Control restoration in teeth that have questionable pulpal or periodontal prognosis which helps in:
- Protection of the pulp from oral cavity .
- Provide anatomic contour ( keep the food away from gingival ) which provides gingival health .
- Facilitate control of caries & plaque( if the contour is kept → so NO plaque ).e.g: patient has erosion lesion , class V, this lesion tend to retain plaque ,so we fill the tooth NOT because patient has sensitivity or caries tooth but to facilitate plaque control .
- Provide resistance against tooth fracture .( if we have very weak walls without support from inside this lead to fracture of tooth structure ).
e.g : if we have huge periapical lesion , we need some time until this lesion is resolve ,we shouldn’t use indirect restoration as crown because this tooth may need retreatment or root canal treatment or may be extraction , so we put the amalgam restoration for awhile and wait for out come before we crown the tooth .
2. Control restoration in teeth that have acute & sever caries .
3. Definitive final restorations ( sometimes the amalgam filling is the treatment of choice if the patient is old( 90years) or life expectancy not good or the patient is ill and can't stay for long time in the dental chair ).
4. as foundation . { When we have tooth canal treatment ,huge cavity and we want to prepare the tooth to receive crown so we fill the space by amalgam ( use the amalgam as part of tooth ).}

Contra indication :
1. If the tooth can NOT properly restored with direct restorations because of functional or anatomical consideration .
2. Significant occlusal problems or deflective contact .( if we want to change the occlusion { to be high or low ) so the patient need to put the crown ( indirect restoration )because amalgam is not enough .
3. If the area to be restored is esthetically important for the patients.

Advantage ( compared to indirect restorations) .
1. Conserve tooth structure .
2. Appointment time .
3. Resistant & retention forms .
4. Economic . →amalgam filling is much cheaper .

Disadvantages : { mainly due to use of pin }.
1. Dentinal microfracture .
2. Microleakage .
3. Decreased strength of amalgam .
4. Resistance form .
5. Penetration & perforation
6. Tooth anatomy →we can't restore tooth anatomy by amalgam so its contraindication to keep the amalgam on tooth structure .

When determining the appropriateness of amalgam in complex post. restoration, the following should be considered .
1. Resistance & retention forms .
2. Status & prognosis of the tooth .
3. Role of the tooth in overall treatment plan.
4. Occlusion , esthetics & economics .
5. Age of the patient .

Clinical technique:
When we have huge missing tooth structure so we use retentive mean:
- We can't do dovetail .
- We use coves ,locks and grooves .
- We use pin , slot to retained amalgam( amalgam foundation ).
Retentive means :
1. Slot →horizontally located .
2. Groove →on axial wall, baccally & lingually .
3. Coves &locks → used to retain amalgam & other restorative material by making an area on dentine to increase surface area & retention .

Slot retained amalgam :
- Slot : retentive groove placed in dentine in a horizontal plane .
- Slot used in combination with pin retention or as an alternative to the pin.
- Indicated in :
1. Short clinical crowns ( placed horizontally →doesn't depend on the vertical dimension of crowns).
2. In cusps that have been reduced 2-3mm from amalgam .

Features of slot preparation :
- More tooth structure is removed in slot than pin .
- Placed on facial ,lingual , distal ,mesial ) aspect .
- They are continuous or segmented .{ depend on the amount of tooth structure missing and whether pins are to be used or not ,so we can make slot taweel or slots 93′are }.
- Placed on gingival floor 0.5 mm (in dentin not in enamel . if it in enamel ,it will create under mind enamel )axial to DEJ ( 0.5mm inside DEJ ).
- It should be at least 0.5mm in depth and 1mm in length .
- Less likely to create microfracture:
Penetrate the pulp
Perforate tooth structure
(That’s mean slot are less retentive than the pin but at the same time it's safer to be used .)

Amalgam foundation:
 Its initially restoration of severely involved tooth .
 The tooth is restoring so the restorative material will serve in place of the missing tooth structure to provide retention & resistance forms for the placement of the definitive indirect restoration.(Foundation to receive crown in the future) .
 It should provide resistant against forces that may fracture the remaining tooth structure .
 The control restoration may serve as foundation .
 Restorative material for foundation :
1. Amalgam . 2. Composite . 3. Resin


 To provide enough resistant from the preparation should be done on sound tooth structure .
 Tooth preparation for amalgam foundation like that of ordinary filling .
 Retentive means ( for a foundation ) may be required like : pins , slots , posts .
 Condense the amalgam inside root canal to provide retention of amalgam filling and for foundation for crown preparation later on ( (neair )( check spelling plz) technique .
 In molars → the large pulp champer & canals provide retention for the foundation & there is no need to use any intra-radicular retentive means .
 We use chamber retention technique in molars only ( not in ant.teeth or premolar because the canal is small and there's no enough chamber so it may be fractured ).

Tooth preparation for amalgam foundation :
 Technique depends on type of retentive means to be used :
1. Pins . 2. Slots. 3. Chamber retention.
 Techniques have in common the " axial location of retention " .

1. Pins retention :
- Used in : severely broken teeth with few or no vertical walls where an indirect restoration is indicated .
- The main difference from using pin for defective restoration is the distance of pin holes from the external surface of the tooth .
- Location of pin from the external surface depend on :
1.External morphology of tooth
2. Type of restoration to be used ( amount of reduction required ).
3. Type of margin to be prepared.
- Many type of indirect restorations, each one certain level of reduction from the tooth to determine the site of pin holes that avoid penetration & perforation .
Y3ne by other way : if we use only pins and amalgam filling →pins in dentin just 0.5 mm., but if we put crown ( indirect restoration ) we have to move the pins more towards the pulp to protect them from exposure during crown preparation.

2. Slots retention :
 Foundation slots are placed slightly more axial .
 Used to oppose locks in vertical walls or to provide retention where no vertical walls are present .
 ( 0.5 -1)mm in depth & width .
 (2 - 4)mm in length .
 If we prepare the tooth for crown we should placed the slot more inside the tooth because when we prepare for the crown the 0.5 in dentin is removed ( that’s mean we remove the retentive mean and the filling will be displaced)so we apply retentive mean farther toward the pulp when we prepare for crown to keep the retention of filling .

3. Chamber retention :
In multirooted endodontically treated teeth .
Depend on size of pulp chamber .
When admission of pulp chamber is adequate to provide retention &the thickness of dentine in the area is enough.
The extension into root canal is (2 – 4) mm when the pulp chamber is 2mm or less .
No advantage from extending amalgam into root canal , when the height of the pulp chamber 4-6 mm .
Natural anatomy of the pulp chamber & the canals provide retention for the amalgam .
Resistance form against tooth fracture is gained by extending the margins of the preparation 2mm on sound tooth structure beyond the foundation .
If the height of pulp chamber < 2mm , the use of prefabricated post , cast post & core , pins & slots should be considered .
Prefabricated post ( gahezh mn 2l soog ,has specific size and length, post :materials are put into the canal to gain retention for the filling or core . ) ,different materials are used ,stainless steel ,gold , titanium ,resin , fiber ,the last 2 is bound to tooth structure .
Cast post : prepared by take impression to tooth and root canal then send it to technician who prepares it as post & core .

Restorative technique :
( Same as class II in addition for use of retentive means )
 Use of desensitizer or bonding system or liner ( because we have deep cavity extend toward the pulp and we have to protect the pulp ) .
 Matrix placement :
- Universal matrix
- Automatrix
- Compound supported copper band → Ivory .
 Inserting the amalgam .
 Contouring & finishing .{ Ca(OH)2 if needed can be used after desensitizer or bonding system .

Automatrix :
Advantages :
1. Convenience.
2. Improve visibility ." no retainer"
3. Ability to place autolock loop buccally or lingually .
4. Decreased time of application .

Disadvantages :
1. Flat band .
2. Difficult to burnish .
3. Difficult to restore definitive proximal contour .
Every lost cusp → we put a pin instead of it .
Amalgam filling , if matrix band end in area has defect ,this result in defect in the restoration .



The end
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Shadi Jarrar
مشرف عام

عدد المساهمات : 997
النشاط : 12
تاريخ التسجيل : 2009-08-28
العمر : 26
الموقع : Amman-Jordan

http://jude.my-rpg.com

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