Prostho perio/ orthodontic practice/ orthodontic continuing education

PERIO-PROSTHOPERIO-PROSTHO
INTERRELATIONSHIPINTERRELATIONSHIP
INDIAN DENTAL ACADEMY
Leader in continuing dental education
www.indiandentalacademy.com
www.indiandentalacademy.comwww.indiandentalacademy.com

CONTENTSCONTENTS
 INTRODUCTIONINTRODUCTION
 OBJECTIVES OF PERIODONTAL PROSTHESISOBJECTIVES OF PERIODONTAL PROSTHESIS
 DEFINITIONSDEFINITIONS
 EXAMINATIONEXAMINATION
 TREATMENT PLANNINGTREATMENT PLANNING
 CONCLUSIONCONCLUSION
 REFERENCESREFERENCES www.indiandentalacademy.comwww.indiandentalacademy.com

INTRODUCTIONINTRODUCTION
The relationship between periodontal health and theThe relationship between periodontal health and the
restoration of teeth is intimate and inseparable.Forrestoration of teeth is intimate and inseparable.For
restorations to survive long term,the periodontium mustrestorations to survive long term,the periodontium must
remain healthy so that the teeth are maintained.For theremain healthy so that the teeth are maintained.For the
periodontium to remain healthy,restorations must beperiodontium to remain healthy,restorations must be
critically managed in several areas so that they are incritically managed in several areas so that they are in
harmony with their surrounding periodontal tissues.harmony with their surrounding periodontal tissues.

Basic objectives of PeriodontalBasic objectives of Periodontal
ProsthesisProsthesis
1. To reduce lateral stresses1. To reduce lateral stresses
2. To distribute stresses equitably2. To distribute stresses equitably
3. To eliminate areas of food impaction3. To eliminate areas of food impaction
4. To eliminate premature and4. To eliminate premature and //or defective contacts;or defective contacts;
elimination of occlusal traumatism - primary or secondary.elimination of occlusal traumatism - primary or secondary.
5. To direct occlusal stresses of functional forces in the long5. To direct occlusal stresses of functional forces in the long
axis of the teethaxis of the teeth
6. With the removal of any conflict between joint and teeth6. With the removal of any conflict between joint and teeth
during normal function.during normal function.
7. To correct tooth contours7. To correct tooth contours
8. To correct TMJ conditions8. To correct TMJ conditions

DEFINITIONSDEFINITIONS
Oral mucosa consists of 3 zones:Oral mucosa consists of 3 zones:
1.1. masticatory mucosamasticatory mucosa..
2.2. specialized mucosa.specialized mucosa.
3. lining mucosa.3. lining mucosa.
GINGIVAGINGIVA is the part of oral mucosa that coversis the part of oral mucosa that covers
the alveolar process of the jaw and surroundsthe alveolar process of the jaw and surrounds
the neck of the teeth.the neck of the teeth.
It is devided into -It is devided into - marginalmarginal,,
attached andattached and
interdental gingiva.interdental gingiva.www.indiandentalacademy.comwww.indiandentalacademy.com

MARGINAL GINGIVA -MARGINAL GINGIVA -
it is terminal border of gingiva,surrounds teeth in collarit is terminal border of gingiva,surrounds teeth in collar
like fashion.like fashion.
it is 1 mm wide and can be separated by probe.it is 1 mm wide and can be separated by probe.
Gingival sulcus -Gingival sulcus -
it is shallow space around tooth bounded by surface ofit is shallow space around tooth bounded by surface of
tooth on one side and epithelium lining of tooth on othertooth on one side and epithelium lining of tooth on other
side.side.
Histologically it is 1.8 mm, clinically it is 2 to 3 mmHistologically it is 1.8 mm, clinically it is 2 to 3 mm
normally.normally.

..
ATTACHED GINGIVA –ATTACHED GINGIVA –
It is firm, resilient and tightly bound to underlyingIt is firm, resilient and tightly bound to underlying
periosteum of alveolar bone.periosteum of alveolar bone.
Width of attached gingiva is very important parameterWidth of attached gingiva is very important parameter
clinically.clinically.
INTERDENTAL GINGIVA –INTERDENTAL GINGIVA –
It occupies gingival embrassure between area of toothIt occupies gingival embrassure between area of tooth
contact.contact.
It can be pyramidal or Col shaped. Its valley likeIt can be pyramidal or Col shaped. Its valley like
depression that connect facial and lingual papilla.depression that connect facial and lingual papilla.

JUNCTIONAL EPITHELIUM:JUNCTIONAL EPITHELIUM:
It is collar like band of non keratinizing epithelium.It is collar like band of non keratinizing epithelium.
3 to 4 layers thick in early life and increases to 10 to 203 to 4 layers thick in early life and increases to 10 to 20
layers with age.Its length ranges from 0.25-1.35mm.layers with age.Its length ranges from 0.25-1.35mm.
very susceptible to infection because of very high turn oververy susceptible to infection because of very high turn over
rate of cells.rate of cells.
STIPPLING:STIPPLING:
It is seen in attached gingiva and centre of interdental papilla,It is seen in attached gingiva and centre of interdental papilla,
absent in marginal gingiva.absent in marginal gingiva.

PERIODONTAL LIGAMENT :PERIODONTAL LIGAMENT :
It consists of principal fibers and elastic fibers.It consists of principal fibers and elastic fibers.
Principal fibers are made of type 1 collagen fibers.Principal fibers are made of type 1 collagen fibers.
Elastic fibers are present in 2 immature forms calledElastic fibers are present in 2 immature forms called
OXYTALAN and ELAUNIN.OXYTALAN and ELAUNIN.
Principal fibers are arranged in 5 groups:Principal fibers are arranged in 5 groups:
1. Transeptal fibers1. Transeptal fibers
2. Alveolar crest fibers2. Alveolar crest fibers
3. Oblique fibers3. Oblique fibers
4. Horizontal fibers4. Horizontal fibers
5. Apical fibers5. Apical fibers
6. Inter radicular fibers6. Inter radicular fibers

ATTACHMENT UNIT:ATTACHMENT UNIT:
Clinical gingival sulcus depth normally measures 1 to 2 mm,Clinical gingival sulcus depth normally measures 1 to 2 mm,
whereas epithilial attachment is 1mm and the connective tissuewhereas epithilial attachment is 1mm and the connective tissue
attachment is 1 mm.attachment is 1 mm.
Alveolar crest is therefore located approximately 2mm apical toAlveolar crest is therefore located approximately 2mm apical to
the base of the sulcus.the base of the sulcus.
PERIODONTAL LIGAMENT :PERIODONTAL LIGAMENT :
It is composed of collagen fibres arranged in bundles, that areIt is composed of collagen fibres arranged in bundles, that are
attached from the cementum of the tooth to alveolar bone of theattached from the cementum of the tooth to alveolar bone of the
jaw.jaw.
In healthy mouth it is 0.25 to 0.1mm wide, widest at margin andIn healthy mouth it is 0.25 to 0.1mm wide, widest at margin and
apex and narrowest in middle third.apex and narrowest in middle third.

PERIODONTITIS:PERIODONTITIS:
It is inflammatory disease of gingiva and or deeperIt is inflammatory disease of gingiva and or deeper
tissues of periodontium and is characterized by pockettissues of periodontium and is characterized by pocket
formation and bone destruction.formation and bone destruction.
Classification:Classification:
1.1. slowly progressive/chronic/adult periodontitisslowly progressive/chronic/adult periodontitis
2.rapidly progressive periodontitis:2.rapidly progressive periodontitis:
a) adult onset periodontitis –prepubertal anda) adult onset periodontitis –prepubertal and
juvenilejuvenile
b) necrotising ulcerative periodontitisb) necrotising ulcerative periodontitis
c) refractory or non responsive periodontitisc) refractory or non responsive periodontitis

GINGIVITIS:GINGIVITIS:
It is defined as inflammation of gingiva, andIt is defined as inflammation of gingiva, and
characterized by presence of inflammatory cellularcharacterized by presence of inflammatory cellular
exudate, edema in gingival lamina propria,exudate, edema in gingival lamina propria,
destructions of gingival fibres,ulceration,anddestructions of gingival fibres,ulceration,and
proliferation of sulcular epithelium.proliferation of sulcular epithelium.

There are 4 stages of gingivitisThere are 4 stages of gingivitis
stage 1 : subclinical,2 to 4 days, GCF flowstage 1 : subclinical,2 to 4 days, GCF flow
increasesincreases
stage 2 : acute,4 to 7 days, bleeds on probing,stage 2 : acute,4 to 7 days, bleeds on probing,
erythemaerythema
stage 3 : chronic,2 to 3 weeks, bluish red,stage 3 : chronic,2 to 3 weeks, bluish red,
texture changestexture changes
stage 4 : advanced, connective tissue breakstage 4 : advanced, connective tissue break
down occurdown occur

TRAUMA FROM OCCLUSION:TRAUMA FROM OCCLUSION:
It is defined as a force originating by movement ofIt is defined as a force originating by movement of
maxillary and mandibular teeth in a way that createsmaxillary and mandibular teeth in a way that creates
a pathological lesion.a pathological lesion.
TYPES:TYPES:
1. Primary occlusal trauma1. Primary occlusal trauma
2. Secondary occlusal trauma2. Secondary occlusal trauma

PERIODONTAL POCKET:PERIODONTAL POCKET:
It is pathologically deepened gingival sulcus, which is one ofIt is pathologically deepened gingival sulcus, which is one of
most important feature of periodontal diseases.most important feature of periodontal diseases.
Clinical significance of a pocket is that if it extends beyond 3 toClinical significance of a pocket is that if it extends beyond 3 to
4 mm, patient has difficulty to maintain normal brushing and4 mm, patient has difficulty to maintain normal brushing and
flossing.flossing.

CLASSIFICATION:CLASSIFICATION:
1.1. GINGIVAL POCKET/PSEUDO POCKET-GINGIVAL POCKET/PSEUDO POCKET-
formed by gingival enlargementformed by gingival enlargement
2.2. PERIODONTAL POCKETPERIODONTAL POCKET ––
occur by destruction of supporting periodontaloccur by destruction of supporting periodontal
tissues. It causes loosening of tooth.tissues. It causes loosening of tooth.
a)a) Suprabony pocketSuprabony pocket - bottom of pocket is- bottom of pocket is
coronal to underlying alveolar bone.coronal to underlying alveolar bone.
b)b) Infrabony pocketInfrabony pocket - bottom of pocket is- bottom of pocket is
apical to level of adjacent alveolar bone.apical to level of adjacent alveolar bone.www.indiandentalacademy.comwww.indiandentalacademy.com

EXAMINATIONEXAMINATION
 VISUAL EXAMINATIONVISUAL EXAMINATION
 ATTACHED GINGIVAATTACHED GINGIVA
 PROBINGPROBING
 MOBILITYMOBILITY
 RADIOGRAPHSRADIOGRAPHS
 HABITSHABITS
 PREPARATION OF TISSUESPREPARATION OF TISSUESwww.indiandentalacademy.comwww.indiandentalacademy.com

VISUAL EXAMINATIONVISUAL EXAMINATION
IT IS IMPORTANT TO EVALUATE THE COLOR,IT IS IMPORTANT TO EVALUATE THE COLOR,
CONSISTENCY,TEXTURE,AND SHAPE OF GINGIVAL UNIT.CONSISTENCY,TEXTURE,AND SHAPE OF GINGIVAL UNIT.
IT IS CRITICAL TO RECOGNISE INITIAL STAGE OF MARGINAL LESIONIT IS CRITICAL TO RECOGNISE INITIAL STAGE OF MARGINAL LESION
THROUGH THE CHANGE OF COLOR AND CONSISTENCY.THROUGH THE CHANGE OF COLOR AND CONSISTENCY.
ADEQUATE LIGHT SOURCE IS ESSENTIAL TO DIFFERENTIATE BITWEENADEQUATE LIGHT SOURCE IS ESSENTIAL TO DIFFERENTIATE BITWEEN
NORMAL AND DISEASED TISSUE.NORMAL AND DISEASED TISSUE.
A FIBROPTIC UNIT IS USED TO EXAMINE INACCESSIBLE AREAS.A FIBROPTIC UNIT IS USED TO EXAMINE INACCESSIBLE AREAS.

ATTACHED GINGIVAATTACHED GINGIVA
 CROWN MARGINS CAN BE GINGIVAL IRRITANTSCROWN MARGINS CAN BE GINGIVAL IRRITANTS
AND PLAQUE TRAPS,SO ENHANCING THEAND PLAQUE TRAPS,SO ENHANCING THE
ATTACHED GINGIVA IS ADVISED FORATTACHED GINGIVA IS ADVISED FOR
RESTORATIONS.RESTORATIONS.
 KERATINISED TISSUE IS OFTEN PRESENT ANDKERATINISED TISSUE IS OFTEN PRESENT AND
MISTAKENLY RESTORED, AFTER WHICHMISTAKENLY RESTORED, AFTER WHICH
RECESSION CONTINUES.RECESSION CONTINUES.

PROBINGPROBING
 THE THINNEST PROBE IS DESIRED,IT PERMITS NOTHE THINNEST PROBE IS DESIRED,IT PERMITS NO
PATIENT DISCOMFORT AND GREATEST EASE INPATIENT DISCOMFORT AND GREATEST EASE IN
DIFFERENTIATING THE DIMENSIONS OF POCKET.DIFFERENTIATING THE DIMENSIONS OF POCKET.
 THESE PROBES ARE CALLIBERATED IN mm, SHOULD BETHESE PROBES ARE CALLIBERATED IN mm, SHOULD BE
PROBED IN 6 AREAS ARROUND THE TOOTHPROBED IN 6 AREAS ARROUND THE TOOTH
 IT SHOULD INCLUDE BIFURCATION AND TRIFURCATIONIT SHOULD INCLUDE BIFURCATION AND TRIFURCATION
AREAS IN POSTERIOR SEGMENTS.ALSO CHECK FORAREAS IN POSTERIOR SEGMENTS.ALSO CHECK FOR
BLEEDING OR EXUDATION AS THESE ARE SIGNS OFBLEEDING OR EXUDATION AS THESE ARE SIGNS OF
PERIODONTAL DISEASES.PERIODONTAL DISEASES.

MOBILITYMOBILITY
 IT IS DETERMINED BY HANDLE OFIT IS DETERMINED BY HANDLE OF
PROBE,PLACED ON BUCCAL AND LINGUALPROBE,PLACED ON BUCCAL AND LINGUAL
SURFACES AND APPLYING PRESSURETO TOOTHSURFACES AND APPLYING PRESSURETO TOOTH
WITH HAND.WITH HAND.
GRADE 1 - slightly more than normalGRADE 1 - slightly more than normal
GRADE 2 - moderately more than normalGRADE 2 - moderately more than normal
GRADE 3 - severe mobility faciolingually,GRADE 3 - severe mobility faciolingually,
mesiodistally with vertical displacement.mesiodistally with vertical displacement.

RADIOGRAPHSRADIOGRAPHS
 RADIOGRAPHS ARE ESSENTIAL FORRADIOGRAPHS ARE ESSENTIAL FOR
DIAGNOSIS,TREATMENT AND MAINTAINANCE INDIAGNOSIS,TREATMENT AND MAINTAINANCE IN
PERIODONTICS.PERIODONTICS.
 AREAS TO BE REVIEWED ON RADIOGRAPH:AREAS TO BE REVIEWED ON RADIOGRAPH:
1. ALVEOLAR CREST RESORPTION1. ALVEOLAR CREST RESORPTION
2. INTEGRITY OF THICKNESS OF LAMINA DURA2. INTEGRITY OF THICKNESS OF LAMINA DURA
3. EVIDENCE OF HORIZONTAL BONE LOSS3. EVIDENCE OF HORIZONTAL BONE LOSS
4. EVIDENCE OF VERTICAL BONE LOSS4. EVIDENCE OF VERTICAL BONE LOSS
5. WIDENED PERIODONTAL LIGAMENT SPACE5. WIDENED PERIODONTAL LIGAMENT SPACE
6. DENSITY OF TRABECULAE OF BOTH ARCHES6. DENSITY OF TRABECULAE OF BOTH ARCHES
7. SIZE AND SHAPE OF ROOTS COMPARED TO7. SIZE AND SHAPE OF ROOTS COMPARED TO
CROWN.CROWN. www.indiandentalacademy.comwww.indiandentalacademy.com

HABITSHABITS
 MAJOR HABIT TO CONSIDER IS BRUXISM.VISUALMAJOR HABIT TO CONSIDER IS BRUXISM.VISUAL
EXAMINATION OF WEAR FACET PATTERNS ANDEXAMINATION OF WEAR FACET PATTERNS AND
RADIOGRAPH OF THICKENED LAMINA DURA AND WIDERADIOGRAPH OF THICKENED LAMINA DURA AND WIDE
PERIODONTAL SPACE SHOWS WETHER PATIENT GRINDSPERIODONTAL SPACE SHOWS WETHER PATIENT GRINDS
DURING SLEEP.DURING SLEEP.
 ONE CONDITION THAT INDICATES BRUXISM IS AONE CONDITION THAT INDICATES BRUXISM IS A
COMPLETE ARCH THAT EXHIBITS MOBILITY DESPITECOMPLETE ARCH THAT EXHIBITS MOBILITY DESPITE
ADEQUATE OSSEOUS SUPPORT.ADEQUATE OSSEOUS SUPPORT.

PREPARATION OF TISSUESPREPARATION OF TISSUES
 IT IS IMPORTANT THAT PATIENT IS TO BE INFORMED OFIT IS IMPORTANT THAT PATIENT IS TO BE INFORMED OF
A PROBLEM AND TO BE EDUCATEDABOUT THAT.AFTERA PROBLEM AND TO BE EDUCATEDABOUT THAT.AFTER
THAT FINAL COURSE OF TREATMENT IS DISCUSSEDTHAT FINAL COURSE OF TREATMENT IS DISCUSSED
WITH PATIENT.WITH PATIENT.
 TREATMENT OBJECTIVES ARE:TREATMENT OBJECTIVES ARE:
1. POCKET ELIMINATION1. POCKET ELIMINATION
2. ESTABLISH PHYSIOLOGIC TISSUE CONTOUR FOR2. ESTABLISH PHYSIOLOGIC TISSUE CONTOUR FOR
SELF CLEANSING AND PHYSIOTHERAPEUTICSELF CLEANSING AND PHYSIOTHERAPEUTIC
MANAGEMENT.MANAGEMENT.
3. MODIFICATION OF TOOTH MORPHOLOGY TO3. MODIFICATION OF TOOTH MORPHOLOGY TO
PROTECT PERIODONTIUM INSULTS.PROTECT PERIODONTIUM INSULTS.
4. ERADICATION OF DYSFUNCTIONAL OCCLUSAL HABITS.4. ERADICATION OF DYSFUNCTIONAL OCCLUSAL HABITS.
5. TOOTH STABILIZATION5. TOOTH STABILIZATION
6. PATIENT CO OPERATION FOR PHYSIOTHRAPEUTICS.6. PATIENT CO OPERATION FOR PHYSIOTHRAPEUTICS.

Treatment planning:Treatment planning:
 A.A. Initial Preparation :Initial Preparation :
The initial preparation is the teaching of oral therapeutics.The initial preparation is the teaching of oral therapeutics.
Oral Physiotherapy :Oral Physiotherapy :
Preparing the patient for maintaining the mouth in a healthyPreparing the patient for maintaining the mouth in a healthy
state.state.
Increases opportunities for patient education and effectiveIncreases opportunities for patient education and effective
dentaldental
hygiene.hygiene.

 B. Preparation of Oral Tissues:B. Preparation of Oral Tissues:
The second most important aspect is to have patientsThe second most important aspect is to have patients
restore gingival tissues to a healthy condition that canrestore gingival tissues to a healthy condition that can
then be maintained with proper instruction.then be maintained with proper instruction.
11) Scaling and currettage) Scaling and currettage
2) Removal of hopelessly involved teeth2) Removal of hopelessly involved teeth
3) Excavation and temporization of caries3) Excavation and temporization of caries
4) Evaluation of teeth for possible endodontic involvement4) Evaluation of teeth for possible endodontic involvement
5) Initiation of orthodontic tooth movement for selective cases5) Initiation of orthodontic tooth movement for selective cases
6) Occlusal Adjustment6) Occlusal Adjustment
7) Fabrication of an acrylic occlusal guard in cases of bruxism7) Fabrication of an acrylic occlusal guard in cases of bruxism
8) Re-evaluation :Done with periodontal probe to record8) Re-evaluation :Done with periodontal probe to record
pocket depth and to determine the necessity of surgery.pocket depth and to determine the necessity of surgery.www.indiandentalacademy.comwww.indiandentalacademy.com

C. SURGERY:C. SURGERY:
Pocket elimination and establishment of physiologicPocket elimination and establishment of physiologic
tissue contours are the prime goals. If scaling andtissue contours are the prime goals. If scaling and
curettage have not attained these objectives, surgerycurettage have not attained these objectives, surgery
is required.is required.
1.Gingivectomy1.Gingivectomy
2.Microgingival procedure2.Microgingival procedure
3.Mucoperiosteal flap entry with osseous3.Mucoperiosteal flap entry with osseous
recontouringrecontouring

Advanced surgical techniques:Advanced surgical techniques:
1.Mandibular molar can have one root removed – Hemisection1.Mandibular molar can have one root removed – Hemisection
2.On maxillary molars, it is possible to remove the distobuccal2.On maxillary molars, it is possible to remove the distobuccal
root or the mesiobuccal root and then to restore this tooth toroot or the mesiobuccal root and then to restore this tooth to
function with the tooth splinted to the adjacent tooth.function with the tooth splinted to the adjacent tooth.
3. Bone transplantation - Add bone to the osseous defects3. Bone transplantation - Add bone to the osseous defects
accomplished byaccomplished by
– Swage procedureSwage procedure
– Osseous coagulam proceduresOsseous coagulam procedures
– Bone from recent extraction sitesBone from recent extraction sites

Esthetic pre prosthetic surgery:Esthetic pre prosthetic surgery:
1. Management of mucogingival problems (soft tissue autograph)1. Management of mucogingival problems (soft tissue autograph)
2. Crown lengthening techniques -.2. Crown lengthening techniques -.
Correct methods commonly used to achieve additional crown length are:Correct methods commonly used to achieve additional crown length are:
- Gingivectomy- Gingivectomy
- Apically positioned mucogingival flaps- Apically positioned mucogingival flaps
- Osteotomy- Osteotomy
- Orthodontic passive or active eruptions- Orthodontic passive or active eruptions
3. Ridge augmentation3. Ridge augmentation::
- To correct excessive loss of bone particularly- To correct excessive loss of bone particularly
in the anterior region.in the anterior region.
- Replacement of hydroxyapatite- Replacement of hydroxyapatite
- Flap surgery- Flap surgery
- Mucosal autografts- Mucosal autografts
4. Ridge reduction4. Ridge reduction

Occlusion and its effect on periodontiumOcclusion and its effect on periodontium
The effect of occlusal forces upon the periodontium isThe effect of occlusal forces upon the periodontium is
influenced by their:influenced by their:
- Severity- Severity
- Direction- Direction
- Duration- Duration
- Frequency- Frequency

Trauma from OcclusionTrauma from Occlusion
 Periodontal injury caused by occlusal forces is called traumaPeriodontal injury caused by occlusal forces is called trauma
from occlusion.from occlusion.

 TFO occurs in three stages:TFO occurs in three stages:
1. Injury1. Injury
2. Repair2. Repair
3. Change in morphology of the periodontium3. Change in morphology of the periodontium
 Injury is produced by excessive occlusal forces.Injury is produced by excessive occlusal forces.
 Natural repair of the injury and restoration of periodontal tissuesNatural repair of the injury and restoration of periodontal tissues
occur if the force on the tooth diminishes or the tooth driftsoccur if the force on the tooth diminishes or the tooth drifts
away from the force (mobility).away from the force (mobility).

TFO changes the tissue environment around theTFO changes the tissue environment around the
inflammatory exudates in 2 ways:inflammatory exudates in 2 ways:
1. It alters the alignment of the transeptal and alveolar crest1. It alters the alignment of the transeptal and alveolar crest
fibres and thus changes the direction of the pathway of thefibres and thus changes the direction of the pathway of the
inflammation so that it extends directly into the periodontalinflammation so that it extends directly into the periodontal
ligaments.ligaments.
2. Excessive occlusal forces produce periodontal ligaments2. Excessive occlusal forces produce periodontal ligaments
damage and bone resorption, which aggravate the tissuedamage and bone resorption, which aggravate the tissue
destruction, caused by inflammation.destruction, caused by inflammation.

Restorative dental procedures and its effect onRestorative dental procedures and its effect on
periodontiumperiodontium
1. Placement of margin1. Placement of margin
2. Gingival Retraction2. Gingival Retraction
3. Temporary coverage and provisional3. Temporary coverage and provisional
restorationrestoration
4. Effect of surface finish of Restoration4. Effect of surface finish of Restoration
5. Cementation5. Cementation

Placement of marginsPlacement of margins
It is most important step in tooth preparation.It influencesIt is most important step in tooth preparation.It influences
marginal integrity of restoration.marginal integrity of restoration.
a. At the crest of the gingivala. At the crest of the gingival
b. Above the gingival crest - supragingivalb. Above the gingival crest - supragingival
c. In the intracrevicular space - subgingivalc. In the intracrevicular space - subgingival

Supra gingival margin placement:Supra gingival margin placement:
 This is advocated based on the studies that found theThis is advocated based on the studies that found the
subgingival margins are detrimental to periodontal health.subgingival margins are detrimental to periodontal health.
 Hunter& Hunter (1990) reported that placing a margin deepHunter& Hunter (1990) reported that placing a margin deep
within the gingival crevice is damaging to the periodontium andwithin the gingival crevice is damaging to the periodontium and
the problem is compounded with wide seating discrepanciesthe problem is compounded with wide seating discrepancies
and cement lines.and cement lines.
 Lang (1995) concluded that the margin, the cement, and theLang (1995) concluded that the margin, the cement, and the
prepared tooth represent a transition zone that profoundlyprepared tooth represent a transition zone that profoundly
affects the ecosystem of the gingival sulcusaffects the ecosystem of the gingival sulcus..

Supragingival margins are easier to prepare accuratelySupragingival margins are easier to prepare accurately
without trauma to soft tissues. They can usually alsowithout trauma to soft tissues. They can usually also
be situated on hard enamel whereas subgingivalbe situated on hard enamel whereas subgingival
margins are often on dentine or cementum.margins are often on dentine or cementum.
 Advantages:Advantages:
>They can be easily finished.>They can be easily finished.
>They are more easily kept clean (oral hygiene can>They are more easily kept clean (oral hygiene can
be maintained)be maintained)
>Impressions are more easily made, with less>Impressions are more easily made, with less
potential for soft tissuepotential for soft tissue
damage.damage.
>Restorations can be easily evaluated at recall>Restorations can be easily evaluated at recall
appointments.appointments.

Subgingival margin placement /lntracrevicular margins:Subgingival margin placement /lntracrevicular margins:
The term Intracrevicular for margin placement implies confinement withinThe term Intracrevicular for margin placement implies confinement within
the gingival crevice. It is preferable to the term subgingival because sub gingival marginsthe gingival crevice. It is preferable to the term subgingival because sub gingival margins
can extend into the functional epithelium and connective tissue, which is a violation of thecan extend into the functional epithelium and connective tissue, which is a violation of the
biologic width and results in localized gingival inflammation.biologic width and results in localized gingival inflammation.
 Clinical situations in which the margins of the restoration is carried into the gingivalClinical situations in which the margins of the restoration is carried into the gingival
sulcus are:sulcus are:
1. Dental caries, cervical erosion or restorations extending subgingivally and a1. Dental caries, cervical erosion or restorations extending subgingivally and a
crown lengthening procedure is not indicated.crown lengthening procedure is not indicated.
2. Proximal contact area extends to the gingival crest.2. Proximal contact area extends to the gingival crest.
3. Additional retention is needed.3. Additional retention is needed.
4. Margin of a metal-ceramic crown is to be hidden behind the labiogingival crest.4. Margin of a metal-ceramic crown is to be hidden behind the labiogingival crest.
5. Root sensitivity cannot be controlled by more conservative procedure, such5. Root sensitivity cannot be controlled by more conservative procedure, such
as application of dentine bonding agents.as application of dentine bonding agents.
6. Modification of axial contour is indicated.6. Modification of axial contour is indicated.
 Subgingival restorative margins are associated with the development of plaqueSubgingival restorative margins are associated with the development of plaque
related inflammatory periodontal disease, primarily because of a shift in the subgingivalrelated inflammatory periodontal disease, primarily because of a shift in the subgingival
micro flora.micro flora.

 The degree and extent of the marginal inflammation that areThe degree and extent of the marginal inflammation that are
associated withassociated with
subgingival margin placement is ,influenced by four factors:subgingival margin placement is ,influenced by four factors:
1. Emergence profile1. Emergence profile
2. Improperly finished margin2. Improperly finished margin
3. Inadequate zone of gingiva3. Inadequate zone of gingiva
4. Violation of biologic width4. Violation of biologic width
Emergence profile:Emergence profile:
Failure to maintain proper emergence profile may be a result ofFailure to maintain proper emergence profile may be a result of
relying on the theory of food deflection when developing crownrelying on the theory of food deflection when developing crown
contours, or it may be a result of failure to remove adequate toothcontours, or it may be a result of failure to remove adequate tooth
structure during tooth preparation.structure during tooth preparation.
Lack of adequate reduction during tooth preparation will necessitateLack of adequate reduction during tooth preparation will necessitate
over bulking the final restoration at the gingival margin for adequateover bulking the final restoration at the gingival margin for adequate
material strength.material strength.
This is particularly true with the porcelain - veneered metal crown.This is particularly true with the porcelain - veneered metal crown.
These over contoured restorations change the emergence profile ofThese over contoured restorations change the emergence profile of
the tooth. This will create a protected area that encourages plaquethe tooth. This will create a protected area that encourages plaque
accumulation and is difficult to clean.accumulation and is difficult to clean.www.indiandentalacademy.comwww.indiandentalacademy.com

 Improperly finished margins (overhangs or large open margins):Improperly finished margins (overhangs or large open margins):
Are probably associated with subgingival margins where large number ofAre probably associated with subgingival margins where large number of
pathologic microorganisms accumulates. Access to these areas for effectivepathologic microorganisms accumulates. Access to these areas for effective
oral hygiene is extremely limitedoral hygiene is extremely limited  inflammatory response.inflammatory response.
 Inadequate zone of attached gingiva:Inadequate zone of attached gingiva:
Attached gingiva is keratinized and firmly attached to the alveolar bone. AnAttached gingiva is keratinized and firmly attached to the alveolar bone. An
adequate gingival band can withstand inadvertent trauma associated withadequate gingival band can withstand inadvertent trauma associated with
operative procedures such as tooth preparation, making impression,operative procedures such as tooth preparation, making impression,
cementation. Also an adequate zone of attached gingival buffers the freecementation. Also an adequate zone of attached gingival buffers the free
gingival margin from the pulling effects of muscle attachments and frena.gingival margin from the pulling effects of muscle attachments and frena.
If zone of attached gingival is somewhat less than adequate, margin ofIf zone of attached gingival is somewhat less than adequate, margin of
restoration should be kept supragingival whenever possible.restoration should be kept supragingival whenever possible.
Introduction of a restorative margin subgingivally with this type of tissue willIntroduction of a restorative margin subgingivally with this type of tissue will
have an adverse impact on periodontal health. The result will be a significanthave an adverse impact on periodontal health. The result will be a significant
amount of marginal inflammation, followed by subsequent attachment loss andamount of marginal inflammation, followed by subsequent attachment loss and
gingival recession. In patients with little or no attached gingival, gingivalgingival recession. In patients with little or no attached gingival, gingival
augmentation procedures can be carried.augmentation procedures can be carried.

 Maynard and WilsonMaynard and Wilson suggest that a bandsuggest that a band
of attached gingival of 3 mm width shouldof attached gingival of 3 mm width should
be present before subgingival marginbe present before subgingival margin
placement is considered.placement is considered.
 Violation of the biologic width:Violation of the biologic width:
Results in inflammatory marginal lesionResults in inflammatory marginal lesion
that will eventually lead to marginalthat will eventually lead to marginal
attachment loss.attachment loss.

Biologic width:Biologic width:
 The biologic width is made up of the junctional epithelium and theThe biologic width is made up of the junctional epithelium and the
supra alveolar connective tissue found apical to the junctionalsupra alveolar connective tissue found apical to the junctional
epithelium.epithelium.
 The coronal apical width ranges from 2 to 3mm with approximatelyThe coronal apical width ranges from 2 to 3mm with approximately
half composed of junctional epithelium and half of connective. tissuehalf composed of junctional epithelium and half of connective. tissue
fibres.fibres.
 The coronal half of the gingival sulcus has a much thicker protectiveThe coronal half of the gingival sulcus has a much thicker protective
layer of epithelium than does the apical half of the sulcus. Thislayer of epithelium than does the apical half of the sulcus. This
coronal region therefore has better resistance to toxic products ofcoronal region therefore has better resistance to toxic products of
dental plaque. It is advisable to place restorations in the coronal halfdental plaque. It is advisable to place restorations in the coronal half
of the gingival crevice. Thus all subgingival margins should beof the gingival crevice. Thus all subgingival margins should be
placed within 1-2 mm of the free gingival margin whenever possible.placed within 1-2 mm of the free gingival margin whenever possible.
 Authors reviewing histologic specimens have reported that theAuthors reviewing histologic specimens have reported that the
average sulcus depth in a healthy patient was 0.5 mm to 1 mm inaverage sulcus depth in a healthy patient was 0.5 mm to 1 mm in
depth. Therefore, the ideal intracrevicular positions for margins aredepth. Therefore, the ideal intracrevicular positions for margins are
0.5 mm beneath the gingival crest. Thus overextension of margin0.5 mm beneath the gingival crest. Thus overextension of margin
placement beneath the gingival on root surfaces impinges on theplacement beneath the gingival on root surfaces impinges on the
gingival connective tissue fibres and the junctional epitheliumgingival connective tissue fibres and the junctional epithelium

Wound Healing considerationWound Healing consideration
 Healing of extensive periodontal surgery usually requires at least 3Healing of extensive periodontal surgery usually requires at least 3
months. Areas treated by scaling, root planning and plaque controlmonths. Areas treated by scaling, root planning and plaque control
without surgery take about 1-2 months for their gingival margins towithout surgery take about 1-2 months for their gingival margins to
stabilize.stabilize.
 Key to the success for sub gingival margins:Key to the success for sub gingival margins:
1. Achieving optimal preprosthetic gingival health.1. Achieving optimal preprosthetic gingival health.
2.Minimizing gingival trauma from rotary instruments during tooth2.Minimizing gingival trauma from rotary instruments during tooth
preparation.preparation.
3.Careful use of gingival retraction cord. The surrounding tissue must3.Careful use of gingival retraction cord. The surrounding tissue must
not be permanently damaged during impression making.not be permanently damaged during impression making.
4.Interim restoration should have polished well-fitting and properly4.Interim restoration should have polished well-fitting and properly
contoured margins.contoured margins.
5.Cement must not be retained in the gingival crevice.5.Cement must not be retained in the gingival crevice.
6.Intracrevicular plaque control must be sustained throughout the6.Intracrevicular plaque control must be sustained throughout the
course of treatment and recall.course of treatment and recall.

7.Properly finished margins7.Properly finished margins
8.Adequate zone of attached gingival8.Adequate zone of attached gingival
9.Proper emergence profile9.Proper emergence profile
10.No violation of biologic width10.No violation of biologic width
At the crest of marginal gingivaAt the crest of marginal gingiva::
The margins of the preparation are not usually placedThe margins of the preparation are not usually placed
at the crest of the marginal gingiva, regardless of howat the crest of the marginal gingiva, regardless of how
precise the margins of the restoration. Microscopically,precise the margins of the restoration. Microscopically,
the margin is rough and an excellent site to harborthe margin is rough and an excellent site to harbor
bacteria since the margin of the gingiva rapidly collectsbacteria since the margin of the gingiva rapidly collects
plaque. This is the site of recurrent decay. If decay doesplaque. This is the site of recurrent decay. If decay does
not result, the plaque causes periodontal disease at thisnot result, the plaque causes periodontal disease at this
most critical area, which is not self-cleansing.most critical area, which is not self-cleansing.

Gingival retraction:Gingival retraction:
 Tissue displacement is commonly needed to obtain adequateTissue displacement is commonly needed to obtain adequate
access to the prepared tooth to expose all necessary surfaces, bothaccess to the prepared tooth to expose all necessary surfaces, both
prepared and unprepared.prepared and unprepared.
 Impressions of intracrevicular finish lines may be extremelyImpressions of intracrevicular finish lines may be extremely
injurious to periodontium depending to a great extent on the qualityinjurious to periodontium depending to a great extent on the quality
and quantity of attached gingival and type of retraction.and quantity of attached gingival and type of retraction.
 All retraction methods induce transient trauma to the junctionalAll retraction methods induce transient trauma to the junctional
epithelium and connective tissue of the gingival sulcus.epithelium and connective tissue of the gingival sulcus.
Methods of Retraction:Methods of Retraction:
1. Retraction cord1. Retraction cord
2. Electrosurgery2. Electrosurgery
3. Rotary gingival curettage3. Rotary gingival curettage
Retraction cord: produce limited gingival recession.Retraction cord: produce limited gingival recession.
It is achieved withChemically impregnated cord.It is achieved withChemically impregnated cord.

Types of chemicals used are:Types of chemicals used are:
a) Vasoconstrictors:a) Vasoconstrictors:8% recemic epinephrine8% recemic epinephrine
Other chemicals used:Other chemicals used:
Aluminium chlorideAluminium chloride
Alum (AIKSo4)Alum (AIKSo4)
Aluminium sulfate and ferric sulfateAluminium sulfate and ferric sulfate
The three criteria for gingival retraction are:The three criteria for gingival retraction are:
1.Effectiveness in gingival displacement and hemostatis1.Effectiveness in gingival displacement and hemostatis
2.Absence of irreversible damage to the gingiva2.Absence of irreversible damage to the gingiva
3.Paucity of untoward systemic effects3.Paucity of untoward systemic effects

 Electrosurgery:Electrosurgery:
 Electrosurgery is a surgical procedure performed on soft tissue utilizingElectrosurgery is a surgical procedure performed on soft tissue utilizing
controlled high frequency electrical (radio-frequency) currents in thecontrolled high frequency electrical (radio-frequency) currents in the
range of 1,500,000 to 75,00,000 cycles per second.range of 1,500,000 to 75,00,000 cycles per second.
 The use of electrosurgery has been recommended for enlargement ofThe use of electrosurgery has been recommended for enlargement of
the gingival sulcus to facilitate impression making. In one technique,the gingival sulcus to facilitate impression making. In one technique,
the inner epithelial lining of the gingival sulcus is removed, thusthe inner epithelial lining of the gingival sulcus is removed, thus
improving access for a subgingival crown margin and effectivelyimproving access for a subgingival crown margin and effectively
controlling post surgical hemorrhage.controlling post surgical hemorrhage.
 In fixed prosthodontics, electrosurgery is used extensively toIn fixed prosthodontics, electrosurgery is used extensively to
adequately expose the subgingival margins of abutment preparationsadequately expose the subgingival margins of abutment preparations
for impression procedure. This procedure is known as Troughing.for impression procedure. This procedure is known as Troughing.
 Electrosurgery is valuable for smoothening and correcting the contoursElectrosurgery is valuable for smoothening and correcting the contours
of edentulous ridges for pontic placement.of edentulous ridges for pontic placement.

 It is contraindicated on or near patient with any electronic medicalIt is contraindicated on or near patient with any electronic medical
device (i.e. cardiac pacemaker, insulin pump) or patients withdevice (i.e. cardiac pacemaker, insulin pump) or patients with
delayed healing as a result of debilitating disease or radiationdelayed healing as a result of debilitating disease or radiation
therapy.therapy.
 It is not suitable on thin attached gingiva e.g. the labial tissue ofIt is not suitable on thin attached gingiva e.g. the labial tissue of
maxillary canines (leads to gingival recession).maxillary canines (leads to gingival recession).
 It should not be used with metal instruments because contact couldIt should not be used with metal instruments because contact could
cause electric shock.cause electric shock.
Rotary gingival curettage:Rotary gingival curettage:
 The concept of rotary curettage was described by Amsterdam inThe concept of rotary curettage was described by Amsterdam in
1954. Rotary curettage is a 'troughing' technique, the purpose of1954. Rotary curettage is a 'troughing' technique, the purpose of
which is to produce limited removal of epithelial tissue in the sulcuswhich is to produce limited removal of epithelial tissue in the sulcus
while a chamfer finish line is being created in tooth structure. Thewhile a chamfer finish line is being created in tooth structure. The
technique, which also has been called 'gingettage', is used with thetechnique, which also has been called 'gingettage', is used with the
subgingival placement of restoration margins.subgingival placement of restoration margins.

Temporary and provisionalTemporary and provisional
coveragecoverage
 Provisional restorations are temporary restorations, whichProvisional restorations are temporary restorations, which
are placed in the mouth for more than a few days to a feware placed in the mouth for more than a few days to a few
months.months.
 To facilitate plaque removal, a provisional restoration mustTo facilitate plaque removal, a provisional restoration must
have good marginal fit, proper contour and a smoothhave good marginal fit, proper contour and a smooth
surface. This is particularly important when the crownsurface. This is particularly important when the crown
margin will be placed apical to the free gingival margin.margin will be placed apical to the free gingival margin.
The contour of these restorations should also beThe contour of these restorations should also be
compatible with the gingival tissues.compatible with the gingival tissues.
Effect of surface finish of Restoration:Effect of surface finish of Restoration:
 A restoration should have a smooth highly polished orA restoration should have a smooth highly polished or
glazed surface. A rough surface retains plaque -leads toglazed surface. A rough surface retains plaque -leads to
inflammation.inflammation.

Cementation:Cementation:
 All intracrevicular margins are checked carefully after cementation for excessAll intracrevicular margins are checked carefully after cementation for excess
cement. The restoration should be seated as close as possible to the toothcement. The restoration should be seated as close as possible to the tooth
preparation. This minimizes the cement line, which enhances plaque formation.preparation. This minimizes the cement line, which enhances plaque formation.
The pathogenic flora of the plaque associated with the cement overhangThe pathogenic flora of the plaque associated with the cement overhang
causes gingival irritation, violates the periodontal attachment and causes bonecauses gingival irritation, violates the periodontal attachment and causes bone
loss.loss.
Morphologic characteristics of restoration and Periodontium:Morphologic characteristics of restoration and Periodontium:
1.Contours1.Contours
2.Embrasures2.Embrasures
3.Crown-root ratio3.Crown-root ratio
Role of contours in periodontal healthRole of contours in periodontal health::
Three prominent theories of crown contour have evolved:Three prominent theories of crown contour have evolved:
1) Gingival protection theory1) Gingival protection theory
2) Muscle actions2) Muscle actions
3) Access for oral hygiene3) Access for oral hygiene

1.Gingival protection theory:1.Gingival protection theory:
 It advocates that contours of restoration be designed toIt advocates that contours of restoration be designed to
protect marginal gingiva from mechanical injury.protect marginal gingiva from mechanical injury.
 Wheeler has remarked that when molars have curvaturesWheeler has remarked that when molars have curvatures
in excess of normal, the gingiva will be overprotected andin excess of normal, the gingiva will be overprotected and
will suffer from lack of proper stimulation.will suffer from lack of proper stimulation.
 The gingival protection theory has been defended primarilyThe gingival protection theory has been defended primarily
on the basis of three elements:on the basis of three elements:
a) Protection of gingival marginsa) Protection of gingival margins
b) Gingival stimulationb) Gingival stimulation
c) Self cleansing contoursc) Self cleansing contours

a) Protection of gingival margins:a) Protection of gingival margins:
 This concept implies that under contouring of the crown will causeThis concept implies that under contouring of the crown will cause
deflection of masticated food onto the gingival margin, forcing it into thedeflection of masticated food onto the gingival margin, forcing it into the
sulcus, thus initiating gingivitis.sulcus, thus initiating gingivitis.
b) Gingival stimulation:b) Gingival stimulation:
 This concept reasons that, as food is masticated it will pass over theThis concept reasons that, as food is masticated it will pass over the
gingiva, stimulating it and causing increased keratinization of thegingiva, stimulating it and causing increased keratinization of the
epithelium. The keratinized epithelium would be more resistant toepithelium. The keratinized epithelium would be more resistant to
periodontal breakdown.periodontal breakdown.
c) Self cleansing contours:c) Self cleansing contours:
 This concept asserts that when food passes over the tooth duringThis concept asserts that when food passes over the tooth during
mastication, the tooth will be cleansed. Numerous authors have showmastication, the tooth will be cleansed. Numerous authors have show
that mastication does not remove plaque at the gingival margin ofthat mastication does not remove plaque at the gingival margin of
teeth. Thus, self-cleansing crown contours apparently are nonexistentteeth. Thus, self-cleansing crown contours apparently are nonexistent
at the gingival margins of the teeth.at the gingival margins of the teeth.

2.Muscle action theory: (Morris & Herlands et al)2.Muscle action theory: (Morris & Herlands et al)
19621962..
 They used the rationale of muscle molding and cleansing,They used the rationale of muscle molding and cleansing,
rather than food impaction to explain the observable clinicalrather than food impaction to explain the observable clinical
phenomena found around natural and artificial crowns.phenomena found around natural and artificial crowns.
 They suggested that overcontouring prevents the normalThey suggested that overcontouring prevents the normal
cleansing action of the musculature and allows food tocleansing action of the musculature and allows food to
stagnate in the overprotected sulcus.stagnate in the overprotected sulcus.
 This theory promotes constant cleansing and moldingThis theory promotes constant cleansing and molding
action by the muscles of the lip, cheek and tongue.action by the muscles of the lip, cheek and tongue.

3.Theory of access for oral hygiene:3.Theory of access for oral hygiene:
This theory is based on the concept that plaqueThis theory is based on the concept that plaque
is the prime etiologic factor in caries and gingivitis. Thusis the prime etiologic factor in caries and gingivitis. Thus
crown contours should facilitate plaque removal, notcrown contours should facilitate plaque removal, not
hinder it. One study showed that an increase inhinder it. One study showed that an increase in
periodontal inflammation when crowns were overperiodontal inflammation when crowns were over
contoured due to decreased access for oral hygiene.contoured due to decreased access for oral hygiene.
Four guidelines to contouring crowns withFour guidelines to contouring crowns with
emphasis on access for oral hygiene will be described.emphasis on access for oral hygiene will be described.
1.Buccal and lingual contours: flat not fat!1.Buccal and lingual contours: flat not fat!
2.Open embrasure2.Open embrasure
3.Location- of contactar areas3.Location- of contactar areas
4.Furcation invoIvement4.Furcation invoIvement

Rules for developing crownRules for developing crown
contours in restorationscontours in restorations
 1.Faciolingual crown dimensions no more than 1 mm1.Faciolingual crown dimensions no more than 1 mm
larger than the facio lingual width at level of the CEJ.larger than the facio lingual width at level of the CEJ.
Possible exception – mandibular molar and secondPossible exception – mandibular molar and second
remolars.remolars.
 2.Facial contours are found in gingival third of the crown2.Facial contours are found in gingival third of the crown
and should notand should not bulge more than ½ mm beyond CEJ.bulge more than ½ mm beyond CEJ.
 3.Lingual contours greatest convexity at gingival third3.Lingual contours greatest convexity at gingival third
and should not protrude more than 0.5 mm lingual.and should not protrude more than 0.5 mm lingual.
 4.Proximal contact points are in the occlusal third of the4.Proximal contact points are in the occlusal third of the
crown. Maxillary molars may be at level of junction ofcrown. Maxillary molars may be at level of junction of
occlusal third and middle third. Proximal contact pointsocclusal third and middle third. Proximal contact points
are buccal to the central fossa line except for maxillaryare buccal to the central fossa line except for maxillary
molars found at middle third.molars found at middle third.

 5.Proximal surfaces between marginal ridges and CEJ5.Proximal surfaces between marginal ridges and CEJ
are flat or slightly concave buccolingually.are flat or slightly concave buccolingually.
 6.Axial transitional line angles are straight between the6.Axial transitional line angles are straight between the
proximal contact point and the CEJ.proximal contact point and the CEJ.
 7.Marginal ridges should be the same height. The facial7.Marginal ridges should be the same height. The facial
½ of any tooth is wider than the lingual. Lingual½ of any tooth is wider than the lingual. Lingual
embrasures are always larger than buccal embrasuresembrasures are always larger than buccal embrasures
when curved occlusally.when curved occlusally.
 8.Crown margin - gingival relationship: Margin should be8.Crown margin - gingival relationship: Margin should be
coronal to gingivaexcept for esthetics, crown length, rootcoronal to gingivaexcept for esthetics, crown length, root
caries, root sensitivity and existing restorations.caries, root sensitivity and existing restorations.

Occlusal surface:Occlusal surface:
..
 Occlusal surfaces should be designed:Occlusal surfaces should be designed:
>To direct masticatory force~ along the long axis>To direct masticatory force~ along the long axis
of tooth.of tooth.
>To restore occlusal dimensions and cuspal>To restore occlusal dimensions and cuspal
contours in harmony with the remainder of thecontours in harmony with the remainder of the
natural dentition.natural dentition.
>The anatomy of the occlusal surface should>The anatomy of the occlusal surface should
provide well-formed marginal ridges and occlusalprovide well-formed marginal ridges and occlusal
sluiceways to prevent interproximal food impactionsluiceways to prevent interproximal food impaction

Embrasures:Embrasures:
 When teeth are in proximal contact, the spaces that widen out from theWhen teeth are in proximal contact, the spaces that widen out from the
contact area are known as embrasures.contact area are known as embrasures.
 The following dimensions of gingival embrasure more important to preservationThe following dimensions of gingival embrasure more important to preservation
of gingival health are:of gingival health are:
1. Height: Distance between contact area and bone margin.1. Height: Distance between contact area and bone margin.
2. Width: Distance mesiodistally between proximal surfaces.2. Width: Distance mesiodistally between proximal surfaces.
3. Depth: Distance faciolingually from contact area joining proximofacial or3. Depth: Distance faciolingually from contact area joining proximofacial or
proximolingual line angles.proximolingual line angles.
 Embrasures protect the gingiva from food impaction and deflect the food toEmbrasures protect the gingiva from food impaction and deflect the food to
massage the gingival surface. They provide spillways for food duringmassage the gingival surface. They provide spillways for food during
mastication and relieve occlusal forces when resistant food is chewed. Themastication and relieve occlusal forces when resistant food is chewed. The
proximal surfaces of the crown should taper away from the contact areas on allproximal surfaces of the crown should taper away from the contact areas on all
surfaces.surfaces.
 Proximal contacts that are narrow buccolingually create enlarged embrasuresProximal contacts that are narrow buccolingually create enlarged embrasures
without sufficient protection against interdental food impaction.without sufficient protection against interdental food impaction.
Broad contact area: suppress gingival papillae inflammationBroad contact area: suppress gingival papillae inflammation

CrownCrown -- root ratioroot ratio
 Is important in determination of abutments because toothIs important in determination of abutments because tooth
stability is influenced by the leverage exerted upon thestability is influenced by the leverage exerted upon the
periodontium. The nature of this leverage depends on theperiodontium. The nature of this leverage depends on the
amount of tooth retained in bone i.e. clinical root. Increaseamount of tooth retained in bone i.e. clinical root. Increase
in the length of the crown create unfavorable leveragein the length of the crown create unfavorable leverage
upon the periodontium.upon the periodontium.
 There are 2 methods of modifying the tooth form to changeThere are 2 methods of modifying the tooth form to change
the unfavorable crown to root ratio:the unfavorable crown to root ratio:
1.Construction of a complete crown (cast)1.Construction of a complete crown (cast)
2.Change the occlusal surface of the tooth with an onlay.2.Change the occlusal surface of the tooth with an onlay.
 Lateral and tipping stresses arise during function when the cuspalLateral and tipping stresses arise during function when the cuspal
inclines are steep or the occlusal topography is too broad.inclines are steep or the occlusal topography is too broad.

 Ideally forces applied to the tooth fall within the periphery of the rootIdeally forces applied to the tooth fall within the periphery of the root
structure in bone. If the direction of the functional forces falls within thestructure in bone. If the direction of the functional forces falls within the
lateral borders of the clinical root, stress is directed vertically upon thelateral borders of the clinical root, stress is directed vertically upon the
periodontium. Conversely, if the force is directed beyond the confinesperiodontium. Conversely, if the force is directed beyond the confines
of the root, tipping stresses are induced.of the root, tipping stresses are induced.
 Narrowing the buccolingual width of the occlusal surfaces ofNarrowing the buccolingual width of the occlusal surfaces of thethe
reconstructed crown encourages a more desirable location for thereconstructed crown encourages a more desirable location for the
mandibular buccal and maxillary lingual cusps in relation to the root.mandibular buccal and maxillary lingual cusps in relation to the root.
 The crown - root ratio is a measure of length of the toothThe crown - root ratio is a measure of length of the tooth
occlusal to alveolar crest of bone compared to the length orocclusal to alveolar crest of bone compared to the length or
the root embedded in the bone. Evaluation is bestthe root embedded in the bone. Evaluation is best
performed using the clinical crown to root ratio.performed using the clinical crown to root ratio.
 A ratio of 1:2 was considered ideal, 1: 1.5 acceptable andA ratio of 1:2 was considered ideal, 1: 1.5 acceptable and
1: 1 – minimal1: 1 – minimal

Relationship of pontic adaptation-Relationship of pontic adaptation-
to soft tissue healthto soft tissue health
 The primary purpose of a pontic is to substituteThe primary purpose of a pontic is to substitute
for a missing tooth. The manner in which thefor a missing tooth. The manner in which the
pontic is designed and adapted to the soft tissuepontic is designed and adapted to the soft tissue
of the edentulous ridge determines whether theof the edentulous ridge determines whether the
surrounding tissues will remain healthy or becomesurrounding tissues will remain healthy or become
diseased.diseased.
 Of prime concern in this region are the degreeOf prime concern in this region are the degree
of pressure, the area of ridge contact and theof pressure, the area of ridge contact and the
embrasure space between the abutment tooth andembrasure space between the abutment tooth and
pontic. Due consideration must be given to thesepontic. Due consideration must be given to these
three factors if good tissue tolerance to ponticthree factors if good tissue tolerance to pontic
placement is to be expected.placement is to be expected.

 Requirements:Requirements:
1.Aesthetically acceptable.1.Aesthetically acceptable.
2.Provide occlusal relationships that are favorable to the2.Provide occlusal relationships that are favorable to the
abutment teeth and opposing teeth and remainder ofabutment teeth and opposing teeth and remainder of
the dentition.the dentition.
3.Restore masticatory effectiveness of the tooth it3.Restore masticatory effectiveness of the tooth it
replaces.replaces.
4.Designed to minimize accumulation of dental plaque4.Designed to minimize accumulation of dental plaque
and food debris and permit access for cleansing by patient.and food debris and permit access for cleansing by patient.
5.Provide embrasures for passage of food. Minimal5.Provide embrasures for passage of food. Minimal
passive contact with the ridge and should not blanch thepassive contact with the ridge and should not blanch the
tissues.tissues.

Design:Design:
 A pontic should cover only as much of a ridge as is in keeping withA pontic should cover only as much of a ridge as is in keeping with
esthetics and comfort. Excessive ridge lapping seriously frustratesesthetics and comfort. Excessive ridge lapping seriously frustrates
proper cleansing and should be avoided.proper cleansing and should be avoided.
 The gingival surface that contacts the ridge should have highlyThe gingival surface that contacts the ridge should have highly
glazed porcelain as the material of choice. Rough surfaces accumulateglazed porcelain as the material of choice. Rough surfaces accumulate
plaque and cause irritation.plaque and cause irritation.
Sanitary or Hygienic Pontic:Sanitary or Hygienic Pontic:
 The term hygienic is used to describe pontics that have no contactThe term hygienic is used to describe pontics that have no contact
with the edentulous ridge. These should be at least 3 mm of spacewith the edentulous ridge. These should be at least 3 mm of space
between the pontic and the ridge so that the patient can maintainbetween the pontic and the ridge so that the patient can maintain
hygiene and this allows the tongue and cheek to remove any foodhygiene and this allows the tongue and cheek to remove any food
particles that may lodge in this area. Where esthetics is not or primeparticles that may lodge in this area. Where esthetics is not or prime
concern, this pontic is the design of choice. Less than 2 mm spaceconcern, this pontic is the design of choice. Less than 2 mm space
causes food entrapment.causes food entrapment.

Modified Ridge lap:Modified Ridge lap:
 Where minimal bone loss exists and esthetics are involved, modifiedWhere minimal bone loss exists and esthetics are involved, modified
ridge lap is the preferable design. It contacts only the buccal surface ofridge lap is the preferable design. It contacts only the buccal surface of
the ridge. It should have only minimal passive contact with the ridge.the ridge. It should have only minimal passive contact with the ridge.
Research has confirmed that excessive pressure causes inflammationResearch has confirmed that excessive pressure causes inflammation
and proliferation of the tissue. The pontic should not blanch the tissue.and proliferation of the tissue. The pontic should not blanch the tissue.
 The lingual surface should have a slight deflective contour to preventThe lingual surface should have a slight deflective contour to prevent
food impaction and minimize plaque accumulation. Ridge contact mustfood impaction and minimize plaque accumulation. Ridge contact must
extend no further lingually than the midline of the edentulous ridge.extend no further lingually than the midline of the edentulous ridge.
Saddle PonticSaddle Pontic // Ridge Lap:Ridge Lap:
 The saddle pontic has a concave fitting surface that overlaps theThe saddle pontic has a concave fitting surface that overlaps the
residual ridge buccolingually. However, saddle designs should beresidual ridge buccolingually. However, saddle designs should be
avoided because the concave gingival surface of the pontic is notavoided because the concave gingival surface of the pontic is not
accessible to cleaning with dental floss, which will lead to plaqueaccessible to cleaning with dental floss, which will lead to plaque
accumulation. This design deficiency has been shown to result inaccumulation. This design deficiency has been shown to result in
tissue inflammation.tissue inflammation.

Periodontal splints:Periodontal splints:
 A splint, according to the Glossary of Periodontic terms is "anA splint, according to the Glossary of Periodontic terms is "an
appliance designed to stabilize teeth". A splint can be fabricated in theappliance designed to stabilize teeth". A splint can be fabricated in the
form of joined composite fillings, fixed bridges, removable partialform of joined composite fillings, fixed bridges, removable partial
prosthesis etc.prosthesis etc.
 The purpose of the splint should be to distribute and direct theThe purpose of the splint should be to distribute and direct the
functional and functional forces, to bring them within the tolerance offunctional and functional forces, to bring them within the tolerance of
the remaining supporting tissues and to eliminate any mobility that maythe remaining supporting tissues and to eliminate any mobility that may
be present. Fixation provides mechanical advantage andbe present. Fixation provides mechanical advantage and
simultaneously restricts excessive tooth movements.simultaneously restricts excessive tooth movements.
The primary purposes of splinting are:The primary purposes of splinting are:
1. Stabilization1. Stabilization
2. Reorientation of force and stress - the unit area of resistance to2. Reorientation of force and stress - the unit area of resistance to
force and stress is increased.force and stress is increased.

 Purposes of splinting are:Purposes of splinting are:
1. Improving form and function of teeth1. Improving form and function of teeth
2. Modifying occlusal contact patterns2. Modifying occlusal contact patterns
3. Adjustment of jaw relations3. Adjustment of jaw relations
4. Improvement of masticatory efficiency.4. Improvement of masticatory efficiency.
 Unilateral splinting is the joining of 2 or more teeth in one plane of anUnilateral splinting is the joining of 2 or more teeth in one plane of an
arch segment. Bilateral splinting or cross-arch splinting involves thearch segment. Bilateral splinting or cross-arch splinting involves the
inclusion of teeth on 2 or more segments of an arch up to and includinginclusion of teeth on 2 or more segments of an arch up to and including
the entire arch.the entire arch.
 Splinting Methods:Splinting Methods:
1. Temporary1. Temporary // ReversibleReversible
2. Provisional2. Provisional
3. Permanent3. Permanent

 Temporary splinting may or may not be followed withTemporary splinting may or may not be followed with
permanent splinting. Some methods of reversiblepermanent splinting. Some methods of reversible
splinting are:splinting are:
a)Ligature wirea)Ligature wire
b)Circumferential wiringb)Circumferential wiring
c)Removable appliances (Hawley's bite planes)c)Removable appliances (Hawley's bite planes)
d)Bondingd)Bonding
 The first 2 methods are rarely used and involveThe first 2 methods are rarely used and involve
wrapping wire around the teeth, tying it in an intricatewrapping wire around the teeth, tying it in an intricate
fashion and then covering it with acrylic.fashion and then covering it with acrylic.
 Removable appliances include Hawley's Retainer and aRemovable appliances include Hawley's Retainer and a
continuous clasp (R.P.D.).continuous clasp (R.P.D.).

Splinting by bondingSplinting by bonding
 The composite resins have greater strength and light curedThe composite resins have greater strength and light cured
bonding permits better control of contours. Temporarybonding permits better control of contours. Temporary
splinting is accomplished with the composite material alonesplinting is accomplished with the composite material alone
or in combination with extracoronal and intracoronal oror in combination with extracoronal and intracoronal or
screen meshes.screen meshes.
 Provisional splinting with full-coverage acrylics:Provisional splinting with full-coverage acrylics:
>This method is commonly used with periodontally>This method is commonly used with periodontally
compromised patients where there is a commitment tocompromised patients where there is a commitment to
fixed splints after periodontal therapy.fixed splints after periodontal therapy.
>Before periodontal treatment,teeth are prepared and heat>Before periodontal treatment,teeth are prepared and heat
processed acrylic treatment restorations are constructedprocessed acrylic treatment restorations are constructed
and cemented with sedative cements.and cemented with sedative cements.

Removable splintsRemovable splints
 More rigid connectors are a precision dovetailMore rigid connectors are a precision dovetail
lock design occupying more embrasure spacelock design occupying more embrasure space
buccolingually and occlusogingivally than castbuccolingually and occlusogingivally than cast
rigid connector. Broken stress connectors arerigid connector. Broken stress connectors are
indicated when tooth malalignment prevents aindicated when tooth malalignment prevents a
common path of insertion.They allow designcommon path of insertion.They allow design
flexibility.flexibility.
 The keyway should be on the distal surface ofThe keyway should be on the distal surface of
the abutment crown, with the key on the mesialthe abutment crown, with the key on the mesial
surface of the adjacent pontic. This arrangementsurface of the adjacent pontic. This arrangement
encourages mesial drift to seal the key in the keyencourages mesial drift to seal the key in the key
way of the connector.way of the connector.

Restoration of root resectedRestoration of root resected
molarsmolars
 In 1886 G.V, Black termed resection of one or more roots "radectomy".In 1886 G.V, Black termed resection of one or more roots "radectomy".
The terminology for the various approaches in resecting the differentThe terminology for the various approaches in resecting the different
roots is far from uniform and very confusing.roots is far from uniform and very confusing.
 According to GPT:According to GPT:
Root amputation: The removal of a root from a multirooted tooth.Root amputation: The removal of a root from a multirooted tooth.
Root resection: Surgical removal of all or a portion of the root beforeRoot resection: Surgical removal of all or a portion of the root before
or after endodontic treatment.or after endodontic treatment.
Hemisection: Surgical separation of a multirooted tooth through theHemisection: Surgical separation of a multirooted tooth through the
furcation area in such a way that a root or roots may be surgicallyfurcation area in such a way that a root or roots may be surgically
removed along with the associated portion of crown.removed along with the associated portion of crown.
 Indications:Indications:
1.Vertical bone loss around one root but not others.1.Vertical bone loss around one root but not others.
2.Furcation invasions with limited vertical bone loss around roots to be2.Furcation invasions with limited vertical bone loss around roots to be
retained.retained.
3.Fracture in the middle or apical one third of root.3.Fracture in the middle or apical one third of root.
4.Caries or unrestorable tooth structure into the furcation.4.Caries or unrestorable tooth structure into the furcation.
5.Root sensitivity5.Root sensitivity
6.A root with untreatable apical lesion6.A root with untreatable apical lesionwww.indiandentalacademy.comwww.indiandentalacademy.com

 Contra indications:Contra indications:
1.Systemic conditions prohibiting extensive1.Systemic conditions prohibiting extensive
dental procedures.dental procedures.
2.Inadequate bone support or unfavorable2.Inadequate bone support or unfavorable
crown root ratio of retained rootscrown root ratio of retained roots
3.Periodontal therapy that cannot produce3.Periodontal therapy that cannot produce
an acceptable gingival architecture withoutan acceptable gingival architecture without
removing supportive bone from adjacentremoving supportive bone from adjacent
teeth.teeth.

 Crown preparation:Crown preparation:
Whenever possible, crown margins should beWhenever possible, crown margins should be
placed supragingivally for ease of impressions,placed supragingivally for ease of impressions,
margin finishing and overall periodontal health.margin finishing and overall periodontal health.
Intracrevicular margin placement may be requiredIntracrevicular margin placement may be required
to cover portions of the root-resected area.to cover portions of the root-resected area.
The crown margin should be apical to the pulpThe crown margin should be apical to the pulp
chamber floor or root canal that was exposed bychamber floor or root canal that was exposed by
resection.resection.

 Hemisection:Hemisection:
When separating the roots of a mandibular molar, oneWhen separating the roots of a mandibular molar, one
root is removed while the other remains. Saving the mesialroot is removed while the other remains. Saving the mesial
root would be desirable, if the molar where the last tooth inroot would be desirable, if the molar where the last tooth in
the arch. The distal root could be used in an abutment for athe arch. The distal root could be used in an abutment for a
short span FPD replacing mesial root.short span FPD replacing mesial root.
If an effort is made to save both roots of the molarIf an effort is made to save both roots of the molar
following the resection the process is describedfollowing the resection the process is described
bicuspidizationbicuspidization. If both roots are maintained, it is. If both roots are maintained, it is
important that they be separated from each other to allowimportant that they be separated from each other to allow
normal gingival embrasure spaces and may be restorednormal gingival embrasure spaces and may be restored
with individual crowns.with individual crowns.

 Crown contours:Crown contours:
The gingival 1/3 of the restoration is fabricatedThe gingival 1/3 of the restoration is fabricated
with a flat emergence profile from the gingiva towith a flat emergence profile from the gingiva to
facilitate oral hygiene.facilitate oral hygiene.
 Occlusion:Occlusion:
Lateral forces are controlled by minimizingLateral forces are controlled by minimizing
cuspal inclines on the resected molar and thecuspal inclines on the resected molar and the
teeth stabilizing it.teeth stabilizing it.

Conclusion:Conclusion:
 The function and future life of the restorationThe function and future life of the restoration
depend upon the preservation of the epithelialdepend upon the preservation of the epithelial
attachment and the normal form of the crown-attachment and the normal form of the crown-
physiologic form and function.physiologic form and function.

References:References:
 Tylman's theory and practice of fIxed prosthodontics.Tylman's theory and practice of fIxed prosthodontics.
 Glickman's clinical periodontologyGlickman's clinical periodontology
 Dental maintainance for patient with periodontal disease.Dental maintainance for patient with periodontal disease.
Thomas GThomas G Wilson.Wilson.
 Fundamentals of fixed prosthodontics - Shillingburg.Fundamentals of fixed prosthodontics - Shillingburg.
 JPD, 1971; 25: 642 - 649.JPD, 1971; 25: 642 - 649.
 JPD, 1981; 45: 268JPD, 1981; 45: 268 -- 277.277.
 JPD, 1982; 48: 396 - 399.JPD, 1982; 48: 396 - 399.www.indiandentalacademy.comwww.indiandentalacademy.com

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