Iatrogenic Factors in

Periodontal Disease

Prepared by:

Lobna El Saadawy

OutlineDefinition

Common factors:

1. Margins of the restoration

2. Contour and open contact

3. Restorative material

4. Design of the removable partial denture

5. Restorative dentistry procedure

6. Malocclusion

7. Orthodontic therapy

8. Extraction of impacted third molar

9. Habits and self-inflicted injuries

10. Radiation therapy

Definition

Inadequate dental procedures that contribute to the deterioration of the periodontal tissues are referred to as iatrogenic factors

1. Margins

of the

restorationI. Overhanging restoration

II. Location of the margin

III. Marginal roughness

A) Overhanging

margins

1) Inhibit the

patient’s

access to

remove

accumulated

plaque

Overhanging

margins1) Change the ecologic

balance of the gingival

sulcus to an area that

favors the growth of

disease-associated

organisms (predominately

gram negative anaerobic

species) at the expense of

the health associated

organisms (predominately

gram-positive facultative

species)

B) Location of the gingival

margin

Subgingival

margins

Equigingival

margins

Supragingiv

al margins

Severe

gingivitis

and deep

pockets

Less

severe

gingivitis

Normal as

in natural

teeth

C) Marginal RoughnessSources of marginal roughness include

i. Grooves and scratches in the

surface of even

a carefully

polished

restoration ex:

porcelain or

gold restoratian

c) Marginal RoughnessSources of marginal roughness include

ii. Inadequate marginal fit of the restoration

*subgingival margins typically shows a gap of

20-40 um between the margin of the

restoration and the unprepared tooth surface

that favors bacterial plaque colonization

C) Marginal RoughnessSources of marginal roughness include:

iii. The gap that exposes the rough prepared

tooth structure following the dissolution of

the luting cement at the restoration margins

SEM photomicrograph of the

cervical margin of a 5-year old

porcelain veneer (P) showing a

small marginal defect and a border

of roughened porcelain (arrows).

(G, gingiva; C, luting composite)

2.

Contour

and

Open

Contacts

I. Overcontoured Crowns

Buccal and lingual contours

Occlusal contours

II. Inadequate interproximal embrasure

I. Overcontoured Crowns

Overcontoured crowns and restorations tend to accumulate plaqueand possibly prevent the self-cleaning mechanisms of the adjacent cheek, lips, and tongue

Overcontoured

Undercontoured

a) Buccal and Lingual

Contours

Prevent self

cleansing

mechanism of the

cheeks, lips and

tongueDoes not have that

much destructive

effect

But under contoured restorations with

absent or shallow buccal deflection ridge

are said to cause gingival trauma due to

injury by rough food

b) Occlusal Contours

Established by marginal ridges and related developmental

grooves.

Normally they deflect food away

from the inter proximal spaces

Occlusal ContoursInappropriate occlusal contours leads to

Food impaction

Plaque retention

Food impaction is defined as the forceful wedging of the food into the periodontium by occlusal forces

Cusps that tend to forcibly wedge food into interproximal embrasures are known as plunger cusps.

Occlusal Contours

Factors leading to food impaction made by Hirschfeld:

Uneven occlusal wear.

Open contact area as a result of the loss of proximal support or from extrusion

Congenital morphologic abnormalities

Improperly constructed restorations

II. Inadequate interproximal

embrasureassociated with papillary inflammation

3.

Restorative

Material

Restorative materials are not in themselves injurious to the periodontal tissues. One exception to this may be self-curing acrylics

• Plaque retention capacity of different restorative materials is different

but yet can be controlled if the restoration was well polished and was accessibile to oral hygiene measures

The undersurface

of pontics in fixed

bridges should

barely touch the

mucosa.

Access for oral

hygiene is

inhibited with

excessive pontic

to tissue contact.

4. Design of

Removable

partial

denture

Removable partial dentures favor

plaque accumulation resulting in:

gingival inflammation

periodontal pocket formation

mobility of the abutment teeth.

Partial dentures that are worn during

both night and day induce more

plaque formation than those worn

only during the daytime

The presence of removable partial

dentures induces both quantitative

and qualitative changes in dental

plaque promoting the emergence of

spirochetal microorganisms

Spirochetes are gram-negative bacteria that are

long, thin and spiral-shaped. some of them are

pathogenic to humans.

There is one species of spirochete that is part of the

natural environment of the human mouth called

Treponema denticola.

Although T. denticola is typically not harmful,but

under certain conditions , it may play a role in the

progression of periodontal disease

It is one of the red complex pathogens .

5.

Restorative

Dentistry

Procedures

The use of rubber dam clamps,

matrix bands, and burs in such a manner as to lacerate the gingiva

results in varying degrees of

mechanical trauma producing

transient injuries that generally

undergo repair

Forceful packing of a gingival retraction

cord into the sulcus to prepare subgingival

margins on a tooth or for the purpose of

obtaining an impression may

mechanically injure the periodontium and

leave behind impacted debris capable of

causing a foreign body reaction.

6. Malocclusion

Irregular alignment of

teeth results in more

difficult plaque control

Several authers

found a positive

correlation between

crowding &

periodontal disease

but others didn’t find

any correlation.

Occlusal DisharmoniesRestorations that doesn’t conform to the

occlusal pattern of the dentition may cause injury to the supporting periodontal tissues (traumatic occlusion – T.F.O.)

Histological features of the periodontium of atooth

subjected to T.F.O. :widened PDL space,

Reduction in the number of collagen content in oblique and horizontal fibers

increase in vascularity and leukocyteinfiltration,

increase in the number of osteoclasts on bordering alveolar bone.

Failure to replace posterior teeth

After the extraction of mandibular 1st

molar with the failure to replace :

1) the initial change is a mesial drifting and tilting of the mandibular second and third molars

2) extrusion of the maxillary first molar

Failure to replace posterior teeth3) As the mandibular second molar tips

mesially, its distal cusps extrude and act as

plunger

4) The distal cusps of the mandibular second

molar wedge between the maxillary first and

second molars and open the contact by

deflecting the maxillary second molar

distally.

7. Periodontal

complications

associated

with

orthodontic

therapyI. Direct effect

II. Indirect effect

I. Indirect

Effecti. Favoring plaque

retention and food debris.

ii. Modifying the gingival

ecosystem resulting in

gingivitis

An increase in Prevotella OdontolyticusPrevotella Intermedia Actinomyces OdontolyticusAggregatibacter

actinomycetemcomitans

*With the decrease in facaulitative microorganisms

II. direct effecti. Creating excessive and/or

unfavourable forces on teeth and

supporting structures

Excessive force produce:

necrosis of PDL and adjacent alveolar bone

increase the risk of apical root resorption

Risk factors for root resorption include :

magnitude of force ,duration of treatment ,continous

versus intermittent force .

Direction of tooth movement ??????

ii. Orthodontic bands placed on

newly erupted permanents with still attached junctional epithelium on

enamel will result in apical

migration & proliferation of the junctional epithelium and an

increased incidence of gingival

recession

The mean alveolar bone loss for adolescents who under went 2 years of orthodontic treatment ranges from 0.1- 0.5 mm (this is found to be of little significance)

as that also noted for the control groups

The degree of bone loss during adultorthodontic care may be higher than that observed in adolescents,

especially if

the periodontal condition is not treated before initiating orthodontic therapy.

III. Other effects

($) Surgical exposure of impacted teeth and orthodontic-assisted eruption has the potential to compromise the periodontal attachment on adjacent teeth .

However , those teeth have more than 9o% of their attachment remains intact

($) It has been reported that the dentoalveolargingival fibers that

are located within the marginal and attached gingiva are stretched

when teeth are rotated during orthodontic therapy

Surgical removal of these gingival fibers in combination with a brief

period of retention

may reduce the incidence of relapse after orthodontic treatment intended to realign rotated teeth

8)

Extraction

of

impacted

third

molars

Extraction of impacted third molars often results in

1) the creation of vertical defects distal to the second molars

However this iatrogenic effect is unrelated to flap design

*But it’s related to presence of plaque , bleeding on probing , pathologically widened follicle , inclination of third molar , root resorption of 2nd molar

* it appears to occur more often when third

molars are extracted in individuals older than 25 years.

2) Another consequence of removal

of third molars include permanent

paresthesia (numbness of the lip,

tongue, and cheek), d.t injury of the

lingual nerve passing distal to third

mandibular molar

9. Habits

and Self

Inflicted

Injuries

I. Tooth brush trauma1. Acute

Erosions & diffuse erythema

Ulcers

Acute gingival abscess d.t.forcefully embeded tooth brush bristle

history : Signs of acute gingival

abrasion are frequently noted when the patient first uses a new brush

2. Chronic

Buccal and lingual recession and attachment loss

Cervical abrasion

II . Chemical Injury 1) allergic inflammatory states, the gingival

changes range from simple erythema to painful vesicle formation and ulceration.

E.x. mouthwashes, dentifrices, or denture

materials are often explain

2) nonspecific injurious effect of chemicals on the gingival tissues.

* topical application of

corrosive drugs such as aspirin , phenol or silver nitrate

III. Tobacco use

It results in :

1) oral leukoplakia

2) Increased incidence of gingival recession,

3) cervical root abrasion, and root caries

4) high incidence of severe periodontitis

10.

Radiation

Therapy

Radiation Therapy

Radiation therapy has cytotoxic effects on both

normal and malignant cells

The typical total dose of radiation for head and

neck tumors is in the range of 5000 to 8000

centiGrays (cGy = 1rad)

The total dose of radiation is given in partial

incremental doses (Fractionation where the typical

dose administrated is in the range of 100 to 1000

cGys per week).

this helps to minimize the adverse effects of the

radiation while maximizing the death rate of the

tumor cells.

Radiation therapy induces

Obliterative Endarteritis resulting in:

i. Soft tissue ischemia and fibrosis

ii. Hypo vascular and hypoxic bone

iii. Osteoradionecrosis

iv. Dermatitis and mucositis

v. muscle fibrosis and trismus (restricting access to oral cavity)

vi. Xerostomia (greater plaque accumulation)

vii. Caries

viii. periodontal attachment loss and teeth loss

ix. Greater risk to periodontal infections

How to prevent the

complications of radiotherapy?

1. The severity of themucositis can be reduced by asking the patient to avoid secondary sources of irritation to the mucous membrane, such as smoking, alcohol, and spicy foods.

2. Use of a chlorhexidine

digluconate mouthrinse may help reduce the mucositis. However,

chlorhexidine mouthrinses having

a high alcohol content that may

act as an astringent, which dehydrates the mucosa, thereby

intensifying the pain.

3. Fluoride application, effective oral hygiene

measures and frequent dental

examination.

4. Consult the oncologist before any surgical

or periodontal procedure to decrease

incidence of osteoradionecrosis

5. Prophylactic antibiotics to avoid

osteomyilitis

6. Restricted use of local anesthetic with vasoconstrictor.

7. Hyperbaric oxygen therapy for treatment

of osteoradionecrosis

Complications

of the Use of

Laser in

Periodontology

1. Pitting and crater formation in cementum

2. Exposure of dentinal tubules, and cementum “peeling”

3. A reduced attachment offibroblasts to Nd:YAG laser treated cementum was observed

Nd:YAG (neodymium-doped yttrium

aluminum garnet; Nd:Y3Al5O12)

In conclusion the use of the

Nd:YAG laser in periodontal

treatment is restricted to the area

of the soft tissue management. No safe removal of calculus is possible

using a Nd:YAG laser.

Erbium:YAG laser

Roughness of the enamel surface after

Er:YAG laser irradiation

After irradiation with the Er:YAG laser

enamel prisms at the rugged surface are

clearly visible, the border between lased

and non lased surface can be seen

Calculus is removed from cementum

using an Er:YAG laser, the irradiated

track is visible, the upper layer of

cementum

is removed, too

calculus

cementum

dentine