Operative dentistry Motamiz OPRD 41

LECTURES lecture 3

WED 1-4-2020

Care of gingival tissues

the Chapter of Objectives

The student will be able to recognize:

(1) Types of irritating factors affecting

the periodontium.

(2) Methods of gingival retraction.

(3) Steps of gingival retraction.

-Restorations must be not only compatible with

the pulp-dentin organ, but also with the periodontium.

-Physiologically, the periodontium considered as

one organ, composed of gingiva, dento-gingival

attachment, periodontal ligaments and alveolar

bone.

If foreign body is forced in normal gingival crevice, it regains its

shape and dimensions once the foreign body is removed. However, if

this space is violated by a foreign body for a long period of time, it

will not regain its shape

Normal gingiva

Diseased gingiva

If the interdental col area inflamed as a

result of operative procedure and this

inflammation did not resolved, pocket

formation and marginal periodontitis

will happen.

periodontium the to factors Irritating

Caries Teeth separation Rubber dam application Cavity preparation Matricing Gingival retraction Impression procedures Temporary restorations Permanent restorations

1- Caries

Surface roughness will enhances plaque

accumulation which increased with

advanced cavitation of the teeth.

The condition ranges from gingivitis to

marginal periodontitis, depending on the

severity of tooth destruction.

2- Teeth separation

Tooth separation by wedges

Tooth separation by elastic separators

prolonged separation can cause irreversible ischemia to

the periodontal ligament blood vessels.

3- Rubber dam application

-Unsuitable clamp or incorrect clamp

application. -If the dental floss used to seat the

rubber dam is pushed forcibly against

the periodontal tissues. - If the floss used as ligature → lacerates entrapped gingiva.

4- Cavity preparation

Gingival laceration due to cavosurface

margin preparation

Prepared proximal box

with injured adjacent

gingival tissues

Vibration due rotary inst. During C. P is the most irritating

factor to the periodontium → laceration of PDL

5- Matricing

a. Matrix bands should be properly contoured buccolingually and

mesiodistally to reproduce normal physiologic tooth form. b. The gingival end of the matrix bands should not exceed the apical extent of the gingival crevice to avoid laceration of gingival attachment. c. Matrix retainers should be properly stabilized by wedges, to avoid

their slippage apically or laterally, which might cause laceration

of the gingiva and underlying periodontal tissues.

6- Gingival retraction

A diagram showing the correct position of the gingival retraction cord

-Cause physical trauma if pushed

beyond the apical extent of the

gingival crevice,

-Constricting chemicals may cause

gingival inflammation with slight

gingival recession

7- Impression procedure

a. Mechanical trauma caused by insertion and

removal of impression materials. b. Catalysts and chemical by-products of rubber

elastomeric impression materials can cause allergic

reactions.

8- Temporary restorations

a. Mechanical trauma and gingival irritation from temporary

restoration try-in, adjustment, cementation and removal. b. Irritating qualities of the cementing medium. c. Excessive residual monomer of resinous temporary

restorations

9- Permanent restorations

Narrow contact Broad contact

vertical food impaction will

occur.

pressure on the interdental col

area and change its anatomy

Restorations made with open contact, not only result in food

stagnation interproximally, but also lead to disruption of the

anterior component of forces which subsequently cause

mesial drifting of teeth.

9- Permanent restorations

Improper occlusal anatomy Improper facial contour

vertical loading on the

periodontium as a

result of high spots

and/or over eruption of

the opposing teeth.

- Over contoured facial and lingual

surfaces deprive gingival tissues from healthy

massaging and stimulating effect of food

deflection, leading to gingival atrophy and

abrasion.

- Under contoured facial and lingual

surfaces encourage food stagnation

and plaque accumulation

9.2- Surface finish of the restorations

Improper surface finish Proper surface finish

-No restoration available which can duplicate the surface

glaze of tooth enamel. -Rough surfaced restorations result in gingival irritation due

to bacterial irritation as a result of plaque accumulation

9.3. Marginal discrepancies

Overhanging margins with Pocket formation

Marginal overhangs and underhangs, in proximity to

the gingival tissues, will harbor bacterial plaque

especially if they are located subgingivally, where

natural and artificial cleansing is difficult.

9.4. Chemical make up of

R.M.

-There are inherent irritating ingredients in the

restorative materials that could participate in

periodontal breakdown:- e.g. Mercury and corrosion products in amalgam - Acid etchants and residual monomers in resin based

tooth colored restorations.

Methods of gingival retraction

1. Physico-mechanical methods

2. Chemical methods

3. Electrosurgical methods

4. Surgical methods

1. Physicomechanical methods:

Gingival retraction cord

Gingival retraction paste Custom made Temporary restoration

2. Chemical methods Chemicals are applied in retraction cords or soft loose cotton rolls or cotton pellets. a. Vasoconstrictors to decreasing hemorrhage. b. Fluid coagulants such as 100% alum, 25% aluminum chloride, 10% aluminum potassium sulphate. They coagulate blood and tissue fluids.

3. Electrosurgical methods

The localized electric energy induces tissue changes and creates surface coagulation of tissues, fluids and oozed blood.

4. Surgical methods It is a process by which the unneeded gingival tissues are surgically removed in the same manner as in periodontal surgery.

Fate of the periodontium: We cannot avoid some gingival irritation which is

reparable and reversible dependent on the following factors:

1. The preoperative condition of the gingiva. 2. The nature of the operative and restorative procedures. 3. Proximity of restoration margins to the gingiva. 4.The restoration form (contact, contour and occlusal

anatomy). 5. Post-restorative healing environment (plaque control measures).

7Evaluation sheet no

1- Mention 3 factors cause gingival irritation?

1- Mention 2 methods of gingival retraction?

CHAPTER 5:

Care of Gingival Tissues

Chapter outline

Irritating factors to the periodontium

Caries

Teeth separation

Rubber dam application

Cavity preparation

Matricing

Gingival retraction

Impression procedures

Temporary restorations

Permanent restorations

Methods of gingival retraction

Physico-mechanical methods

Chemical methods

Electrosurgical methods

Surgical methods

Fate of the periodontium

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Objective of Chapter (5)

In the end of this chapter, the student will be able to

recognize:

(1) Types of irritating factors affecting the periodontium.

(2) Methods of gingival retraction.

(3) Steps of gingival retraction.

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Restorations must be not only compatible with the

pulp-dentin organ, but also with the periodontium.

Destroyed pulp tissues can be replaced using inert filling

materials; yet destroyed periodontal tissues cannot be

replaced. Physiologically, the periodontium considered as

one organ, composed of gingiva, dento-gingival

attachment, periodontal ligaments and alveolar bone. Any

irritation affecting one of these components will be

followed by a reaction in the rest of the components.

The normal free gingival margin has a knife-edge

relationship to the facial and lingual surfaces of teeth. This

knife-edge relationship discourages food and plaque

accumulation in these areas. Any inflammation in the

gingiva will render it edematous, and will predispose to

food and plaque accumulation.

If foreign body is forced in normal gingival crevice,

it regains its shape and dimensions once the foreign body is

removed. However, if this space is violated by a foreign

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body for a long period of time, it will not regain its shape.

The interproximal gingiva extends around the

contact area, with its maximum extent at the buccal and

lingual papillae, creating a saddle area known as the

interdental col area. If the interdental col area inflamed as a

result of operative procedure and this inflammation did not

resolved, pocket formation and marginal periodontitis will

happen. The normal facial and lingual contours of teeth

distribute the food during mastication in such a manner that

stimulate and massage the gingival tissues.

Healthy gingiva Diseased gingiva

Irritating factors to the periodontium:

The periodontium is irritated by many factors prior

to, during and after cavity preparation.

These irritating factors are:

1. Caries:

Caries will cause gingival inflammation even in an

early stage as enamel demineralization due to its surface

roughness. This will enhances plaque accumulation which

increased with advanced cavitation of the teeth. The

condition ranges from gingivitis to marginal periodontitis,

depending on the severity of tooth destruction. Moreover,

periodontal reaction will be more severe with cariogenic

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loss of contact and contour.

2. Teeth separation:

Teeth separation for examination or accessibility

could irritate the periodontium. If

teeth separation exceeded the

periodontal ligament space (0.2 - 0.5

mm), the periodontal ligaments will

be compressed on one side of the

teeth and torn on the other side.

Moreover, prolonged separation can

cause irreversible ischemia to the periodontal ligament

blood vessels.

3. Rubber dam application:

Rubber dam could be hazardous to the gingiva and

the periodontal ligaments. Many factors can traumatize

gingival tissues during rubber dam application as the use of

unsuitable clamp or incorrect clamp application. In

addition, if the dental floss used to seat the rubber dam is

pushed forcibly against the periodontal tissues and finally

if the floss used as a ligature strangulates or lacerates

entrapped gingiva.

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4. Cavity preparation:

a. Vibration due to rotary instrumentation is the most

irritating factor to the periodontium. It can lead to

laceration of the periodontal ligament fibers.

b. Preparation of proximal portion of any tooth can

usually cause injury to the adjacent gingival tissues.

The gingival tissues can be protected by preserving

the proximal plate of enamel during gross cavity

preparation. Also placement of wedges

interproximally will protect the underlying

periodontium from mechanical trauma by

instrumentation.

c. Preparation of the gingival cavosurface margins can

cause laceration of the gingival tissues.

5. Matricing:

a. Matrix bands should be properly contoured

buccolingually and mesiodistally to reproduce

normal physiologic tooth form.

b. The gingival end of the matrix bands should not

exceed the apical extent of the

gingival crevice to avoid

laceration of gingival

attachment.

c. Matrix retainers should be

properly stabilized by wedges,

to avoid their slippage apically

or laterally, which might cause laceration of the

gingiva and underlying periodontal tissues.

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6. Gingival retraction:

Gingival retraction procedures are designed to control

the peripheral components of the periodontium prior to

impression procedures. Some destruction could happen if:

a. Gingival retraction cords can cause physical trauma

if pushed beyond the apical extent of the gingival

crevice, or if they strangulated gingival tissues

against the tooth surface. Gingival laceration may

occur which may be followed by alveolar bone

resorption.

b. Constricting chemicals may cause gingival

inflammation with slight gingival recession. In

severe cases, acute inflammation may occur with

considerable gingival recession.

7. Impression procedures:

The periodontium could be affected by impression

procedures and materials as a result of:

a. Mechanical trauma caused by insertion and removal

of impression materials.

b. Catalysts and chemical by-products of rubber

elastomeric impression materials can cause allergic

reactions.

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8. Temporary restorations:

These restorations and their fabrication could be traumatic

as a result of:

a. Mechanical trauma and

gingival irritation from

temporary restoration try-in,

adjustment, cementation and

removal.

b. Irritating qualities of the cementing medium.

c. Excessive residual monomer of resinous temporary

restorations.

9. Permanent restorations:

9.1 . Anatomy of permanent restorations:

Final restorations should properly restore contact, contour

and occlusal anatomy.

a. Under contoured facial and lingual surfaces

encourage food stagnation and plaque accumulation.

b. Over contoured facial and lingual surfaces deprive

gingival tissues from healthy massaging and

stimulating effect of food deflection, leading to

gingival atrophy and abrasion.

c. Restorations made with open contact, not only result

in food stagnation interproximally, but also lead to

disruption of the anterior component of forces which

subsequently cause mesial drifting of teeth.

d. Restorations made with too broad proximal contact

will cause pressure on the interdental col area and

change its anatomy.

e. If the contact areas are made too narrow, vertical

food impaction will occur.

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f. Restorations made with defective occlusal anatomy

will cause either vertical loading on the periodontium

as a result of high spots and/or overeruption of the

opposing teeth.

9.2. The surface finish of the restorations:

There is no restoration available which can duplicate

the surface glaze of tooth enamel. Rough surfaced

restorations result in gingival irritation due to bacterial

irritation as a result of plaque accumulation.

9.3. Marginal discrepancies:

Marginal overhangs and

underhangs, in proximity to the

gingival tissues, will harbor

bacterial plaque especially if they

are located subgingivally, where

natural and artificial cleansing is

difficult.

9.4. Chemical make-up of the restorative materials:

There are inherent irritating ingredients in the

restorative materials that could predispose or participate in

periodontal breakdown. These irritating ingredients are e.g.

mercury and corrosion products of amalgam, acid etchants

as well as residual monomer in resin based tooth-colored

restoratives.

Methods of gingival retraction:

1. Physico-mechanical methods:

The gingiva is forced away from the tooth surface,

laterally and apically. Usually one of three techniques is

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used:

a. Custom made temporary restorations with bulky

temporary cements like ZOE results in gingival

retraction after 24 hours.

b. Rolled cotton or synthetic cords are forced into the

gingival sulcus which results in gingival retraction

within 30 minutes.

c. Heavy weight rubber dam with proper interseptal

dimensions produces an immediate effect.

2. Chemical methods:

Chemicals are carried out to the field of operation in

cords or soft loose cotton rolls or cotton pellets. Chemicals

used are either:

a. Vasoconstrictors that decrease the size of blood

capillaries, thus decreasing hemorrhage, tissue fluid

seepage and consequently the size of the free

gingiva.

b. Fluid coagulants such as 100% alum, 25% aluminum

chloride and 10% aluminum potassium sulphate.

They coagulate blood and tissue fluids locally,

creating a surface layer that is sealant against blood

and crevicular fluid seepage.

Steps of gingival retraction: Use of well compacted woven cords, or drawn cotton

rolls. Measure the tooth diameter before cutting the cord. Start packing from one end of the cord going to the

other end. The packing tools should be blunt. Apply steady static load directed apically and

slightly towards the tooth Surface to preserve

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periodontal attachment. Remove the packed retraction cord in the presence of

moisture to act as a lubricant. After completion of the impression procedure or the

direct wax pattern, remove the remaining packed items and curette the field to create a healthy blood clot for healing.

For assuring healthy healing, adequate temporary restoration and efficient plaque control measures should be carried out.

3. Electrosurgical methods:

Alternating electric current will

be used for gingival retraction.

Electric current pass through human

body without inducing shocks. The

localized energy induces tissue

changes limited to the superficial 2-3

cell layers. It creates surface

coagulation of tissues, their fluids and oozed blood results

in physical removal of the gingival tissues.

4. Surgical methods:

It is a process by which the unneeded gingival

tissues are surgically removed in the same manner as in

periodontal surgery. Apical repositioning of the periodontal

attaching apparatus is performed to create a healthy

gingiva that can be safely and easily retracted by one or

more of the above mentioned methods.

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Fate of the periodontium:

The most meticulous operator cannot avoid some

irritation to the periodontium. However, such irritation is

repairable and reversible depending on the following

factors: 1. The preoperative condition of the gingiva (previously

healthy). 2. The nature of the operative and restorative procedures. 3. Proximity of the restoration margins to the gingiva. 4. The restoration form (contact, contour, and occlusal

anatomy). 5. Post-restorative healing environment (plaque control

measures).