Relining rebasing and repair of complete denture/ dental courses

REBASING AND
REPAIR OF
COMPLETE
DENTURE
INDIAN DENTAL ACADEMYINDIAN DENTAL ACADEMY
Leader in continuing Dental EducationLeader in continuing Dental Education
www.indiandentalacademy.comwww.indiandentalacademy.com

ContentsContents
► INTRODUCTION
► DEFINITION
► TREATMENT RATIONALE
► INDICATIONS and CONTRAINDICATIONS
► PRETREATMENT PROCEDURES
► REQUIREMENTS OF SUCCESSFUL MATERIALS
► TYPES OF RESILIENT LINERS
► REVIEW OF LITERATURE
► CLINICAL IMPRESSION PROCEDURES
► LABORATORY PROCEDURES
► CAUSES OF FRACTURE IN DENTURES
► MATERIALS USED FOR DENTURE REPAIR
► METHODS FOR REPAIR
► METHODS TO STRENGTHEN THE REPAIRED PORTION
► PREVENTION OF DENTURE FRACTURE
► SUMMARY
► REFERENCES www.indiandentalacademy.com

INTRODUCTIONINTRODUCTION
•Both biological supporting tissues and materials used in complete
denture fabrication are vulnerable to time- dependent changes.
•When denture needs to be refitted, it usually indicates undermined
retention, sore spots, and variable denture bearing tissue hyperemia.
•The need for “servicing” complete dentures to keep pace with the
changing surrounding and supporting tissues is mandatory.
•The relining and rebasing of complete dentures involves solving all of
the problems encountered in the construction of new dentures, except
positioning individual teeth.
•The materials are formulated to be soft, resilient and help to form
intervening cushion, consequently the transmission of masticatory forces
are equalized by eliminating pressure spots. This results in reduced
trauma to supporting tissues without sacrificing the contact.
www.indiandentalacademy.com

DEFINITIONSDEFINITIONS
► RELINING –RELINING –
-- It is the process of adding some material to the tissue side of aIt is the process of adding some material to the tissue side of a
denture to fill the space between the tissue and the denture base.denture to fill the space between the tissue and the denture base.
(Winkler) Or(Winkler) Or
- The procedure used to resurface the tissue side of a denture with- The procedure used to resurface the tissue side of a denture with
new base material, thus producing an accurate adaptation to thenew base material, thus producing an accurate adaptation to the
denture foundation area. (GPT-8)denture foundation area. (GPT-8)
► REBASING –REBASING –
- It is a process of replacing all the base material of a denture.- It is a process of replacing all the base material of a denture.
(Winkler)(Winkler) OrOr
- The laboratory process of replacing the entire denture base material- The laboratory process of replacing the entire denture base material
on an existing prosthesis. (GPT-8)on an existing prosthesis. (GPT-8)

TREATMENT RATIONALETREATMENT RATIONALE
► The foundation that supports a denture changes adversely as a resultThe foundation that supports a denture changes adversely as a result
of varying degrees and rates of residual ridge resorption.of varying degrees and rates of residual ridge resorption.
► These changes may be insidious or rapid, but they are progressiveThese changes may be insidious or rapid, but they are progressive
and inevitable and are accompanied by:-and inevitable and are accompanied by:-
Loss of retention and stability.Loss of retention and stability.
Loss of vertical dimension of occlusion.Loss of vertical dimension of occlusion.
Loss of support for facial tissues.Loss of support for facial tissues.
Horizontal shift of dentures:- Incorrect occlusal relationships.Horizontal shift of dentures:- Incorrect occlusal relationships.
Reorientation of occlusal plane.Reorientation of occlusal plane.
Reline RebaseReline Rebase
Minimal to moderate Moderate to maximalMinimal to moderate Moderate to maximal
changes changeschanges changes

► The reasons for relining are:-The reasons for relining are:-
1)1) To Improve Retention & Stability:-To Improve Retention & Stability:-
- Loss of fit will make the maintenance of peripheral seal impossible- Loss of fit will make the maintenance of peripheral seal impossible
and will greatly impair the retentive effects of adhesion & cohesion.and will greatly impair the retentive effects of adhesion & cohesion.
- It may permit a rocking & tilting of the denture during function and- It may permit a rocking & tilting of the denture during function and
in extreme cases in the lateral movement.in extreme cases in the lateral movement.
2)2) To Restore the Vertical Dimension:-To Restore the Vertical Dimension:-
- If the vertical dimension to which a denture was made is reduced,- If the vertical dimension to which a denture was made is reduced,
masticatory efficiency is impaired, but the previous efficiency canmasticatory efficiency is impaired, but the previous efficiency can
usually be restored by relining.usually be restored by relining.
3)3) To Improve the Appearance:-To Improve the Appearance:-
- Over-closure is noticed as the protrusion of the mandible and an- Over-closure is noticed as the protrusion of the mandible and an
undue approximation of the nose and chin, giving an appearance ofundue approximation of the nose and chin, giving an appearance of
age.age.

4)4) To Restore the Evenness of Occlusal Pressure:-To Restore the Evenness of Occlusal Pressure:-
- When there is any alteration in the fit of the dentures, there will be- When there is any alteration in the fit of the dentures, there will be
some alteration of the pressure transmitted to the tissues when thesome alteration of the pressure transmitted to the tissues when the
teeth are brought into occlusion.teeth are brought into occlusion.
5)5) To Relieve Pain:-To Relieve Pain:-
- If a denture has been worn with comfort and then becomes painful, it- If a denture has been worn with comfort and then becomes painful, it
is usually due to the alteration in the supporting tissues allowing theis usually due to the alteration in the supporting tissues allowing the
dentures to tilt, rock or move, and transmit undue pressure on onedentures to tilt, rock or move, and transmit undue pressure on one
area.area.

INDICATIONSINDICATIONS
► Immediate dentures at 3-6 months after their original construction.Immediate dentures at 3-6 months after their original construction.
► When the residual alveolar ridges have resorbed and the adaptationWhen the residual alveolar ridges have resorbed and the adaptation
of the denture bases to the ridges is poor.of the denture bases to the ridges is poor.
► Persistent denture sore mouth.Persistent denture sore mouth.
► Congenital or acquired oral defect:Congenital or acquired oral defect: (Acquired defect due to surgery(Acquired defect due to surgery
for malignancy, trauma, congenital defects like cleft palate)for malignancy, trauma, congenital defects like cleft palate)
► The need for promotion of mucosal healing.The need for promotion of mucosal healing.
► Irregular foundation:Irregular foundation: Sharp knife edge residual ridge, maxillary orSharp knife edge residual ridge, maxillary or
mandibular tori, prominent myelohyoid ridge.mandibular tori, prominent myelohyoid ridge.
► Single denture opposing natural teeth.Single denture opposing natural teeth.
► Radiation therapy for tumors of face and neck.Radiation therapy for tumors of face and neck.

CONTRAINDICATIONSCONTRAINDICATIONS
1) When an excessive amount of resorption has taken place.1) When an excessive amount of resorption has taken place.
2) When abused soft tissues are present.2) When abused soft tissues are present.
3) When the patient complains of TMJ problems.3) When the patient complains of TMJ problems.
4) If the dentures have poor esthetics or unsatisfactory jaw relationships.4) If the dentures have poor esthetics or unsatisfactory jaw relationships.
5) If the dentures create a major speech problems.5) If the dentures create a major speech problems.
6) When severe osseous undercuts exist.6) When severe osseous undercuts exist.

PRETREATMENT PROCEDURESPRETREATMENT PROCEDURES
► TISSUE PREPARATION:-TISSUE PREPARATION:-
1) Excessive hypertrophic tissue should be surgically removed. The1) Excessive hypertrophic tissue should be surgically removed. The
dentures can be used as a surgical splint.dentures can be used as a surgical splint.
2) Oral mucosa should be free of areas of irritation.2) Oral mucosa should be free of areas of irritation.
3) Removal of the dentures from the mouth during sleep several weeks3) Removal of the dentures from the mouth during sleep several weeks
before treatment commences, if the patient wears his dentures duringbefore treatment commences, if the patient wears his dentures during
sleep.sleep.
4) The dentures should be left out of the mouth at least 2-3 days before4) The dentures should be left out of the mouth at least 2-3 days before
making the final impression.making the final impression.
5) Daily massage of the soft tissues is helpful to stimulate blood supply.5) Daily massage of the soft tissues is helpful to stimulate blood supply.

► DENTURE PREPARATION:-DENTURE PREPARATION:-
1) Pressure areas on the tissue surface of the dentures should be1) Pressure areas on the tissue surface of the dentures should be
relieved.relieved.
2) Minor occlusal disharmony is corrected by selective grinding.2) Minor occlusal disharmony is corrected by selective grinding.
3) Small border inadequacies are corrected.3) Small border inadequacies are corrected.
4) A correct posterior palatal seal area should be established before the4) A correct posterior palatal seal area should be established before the
final impression. Green stick compound and autopolymerizingfinal impression. Green stick compound and autopolymerizing
acrylic resin can be used for this purpose.acrylic resin can be used for this purpose.

► PRINCIPAL PITFALLS:-PRINCIPAL PITFALLS:-
1) Do not increase the occlusal vertical dimension.1) Do not increase the occlusal vertical dimension.
2) Multiple even contacts should be present in centric relation.2) Multiple even contacts should be present in centric relation.
3) Do not permit the maxillary denture to move forward during3) Do not permit the maxillary denture to move forward during
impression making.impression making.
4) Ensure that CR and CO are identical.4) Ensure that CR and CO are identical.
5) Ensure that an accurate PPS has been established.5) Ensure that an accurate PPS has been established.
6) An equal thickness of final impression material should be used.6) An equal thickness of final impression material should be used.

Ideal requirements of successful materialsIdeal requirements of successful materials
► Ease of processing
► Dimensional stability during and after processing
► Low water absorption
► Adequate bond strength to rigid denture base resin
► High abrasion resistance: To resist rupture during use.
► Permanent resiliency: It should retain its resilience for longer period
► Colour stability
► Minimum solubility in saliva: Plasticizer should not leach out
► No adverse effect on denture base: Like distortion, reduction of
strength, crazing or blanching.
► Ease in cleansing
► Biocompatibility

Types of Resilient linersTypes of Resilient liners
► Natural rubbers.
► Vinyl co-polymers.
► Hydrophilic polymers.
► Silicone based compounds.
► Acrylic based compounds.
► Treatment liners (soft conditioners)
Room temperature polymerized condensation
silicone rubber.
γ-methacrylate propyl trimethoxy silane
heat polymerized silicone rubbers
(molloplast B )

Why soft denture liners be used rather than rebasing an
acrylic denture base?
Soft liner serves as aSoft liner serves as a “shock absorber”“shock absorber”
Short term soft liner Long term soft liner
Chemically activated soft liner
Poly methyl/ethyl methacrylate
Mixed with 60%-80% plasticizer
Dibutyl phthalate
Slipping motion permits rapid change
in the shape of the soft liner and
provides cushioning effect
•Heat activated
Powders –acrylic resin polmers and
Copolymers
Liquid – acrylic and plasticizers
•Silicone based compounds

LIMITATIONS IN USE OF SOFT LINERSLIMITATIONS IN USE OF SOFT LINERS
► Reduction in denture base strengthReduction in denture base strength
► Loss of softness and resilienceLoss of softness and resilience
► Colonization of candida albicansColonization of candida albicans
► Difficulty in keeping soft liners clean using normal dentureDifficulty in keeping soft liners clean using normal denture
cleaning methodscleaning methods
► Dimensional instabilityDimensional instability
► Failure of adhesionFailure of adhesion
► Difficulty in finishing and polishingDifficulty in finishing and polishing
► Change of colorChange of color

Review of LiteratureReview of Literature
► According toAccording to Lammie and StorerLammie and Storer, (1958), (1958) resilient liner could beresilient liner could be
useful in the complete lower denture where the patient shows a senileuseful in the complete lower denture where the patient shows a senile
atrophy, in developing maximal retention where the ridges haveatrophy, in developing maximal retention where the ridges have
bilateral undercut, in mouth where a hard median palatal raphae isbilateral undercut, in mouth where a hard median palatal raphae is
associated with a poor retentive and in obturators for acquired andassociated with a poor retentive and in obturators for acquired and
congenital clefts of palate.congenital clefts of palate.
► Bates and SmithBates and Smith (1965)(1965) concluded that most of the soft dentureconcluded that most of the soft denture
liners had satisfactory bond strength and showed that the heat cureliners had satisfactory bond strength and showed that the heat cure
soft denture liners have intimate contact with diffused bonding whensoft denture liners have intimate contact with diffused bonding when
materials are cure against an acrylic dough.materials are cure against an acrylic dough.
► Wilson et al (1966)Wilson et al (1966) defined a conditioning material as a soft materialdefined a conditioning material as a soft material
which is applied temporarily to the fitting surface of the denture forwhich is applied temporarily to the fitting surface of the denture for
the purpose of allowing a more equal distribution of load, thusthe purpose of allowing a more equal distribution of load, thus
permitting the mucosal tissue to return to their normal position. Theypermitting the mucosal tissue to return to their normal position. They
demonstrated liquid component contain a plasticizer and concludeddemonstrated liquid component contain a plasticizer and concluded
that dibutylpthalate and ethanol were also present.that dibutylpthalate and ethanol were also present.

► Kawano F. (1991) observed the effect of the proportion and thickness
of soft lining materials on pressure distribution on the supporting
tissue under the denture. He also suggested that soft lining materials
act to distribute functional stress uniformly on the supporting tissues
and a 3mm thickness of the soft lining material is most suitable for
improving the pressure distribution on supporting tissues under the
denture.
► Dootz E.K. et al (1993) in their study, on comparison of physical
properties of eleven soft denture lining materials found that the
accelerated aging of lining dramatically affected the physical and
mechanical properties of many of the elastomers. According to them
no single soft denture lining material proved to be superior to others.
They have also stated that essential physical properties required for
soft denture lining material have not been defined and the data
obtained in this study would support the development of a
specification for soft denture lining materials.

Linear dimensional change of heat-cured acrylicLinear dimensional change of heat-cured acrylic
resin complete dentures after reline and rebase -resin complete dentures after reline and rebase -
Edmond , Chow, and Clark (1998)Edmond , Chow, and Clark (1998)
► Twenty-two maxillary and mandibular complete denture bases withTwenty-two maxillary and mandibular complete denture bases with
artificial teeth and fine crosses were marked on the incisal edges ofartificial teeth and fine crosses were marked on the incisal edges of
the central incisors and the supporting cusps of the second molarthe central incisors and the supporting cusps of the second molar
teeth.teeth.
► Distances between the marks were measured with a high resolutionDistances between the marks were measured with a high resolution
traveling microscope.traveling microscope.
► Heat-cured acrylic resin was processed.Heat-cured acrylic resin was processed.
► Results of the rebasing procedure were similar to that of the relineResults of the rebasing procedure were similar to that of the reline
except that only 0.1% intermolar shrinkage was found on theexcept that only 0.1% intermolar shrinkage was found on the
maxillary denture.maxillary denture.
► ConclusionConclusion.. Shrinkage was approximately 0.15 mm for an interarchShrinkage was approximately 0.15 mm for an interarch
distance of 50 mm.distance of 50 mm.
► CLINICAL IMPLICATIONSCLINICAL IMPLICATIONS
► This study demonstrated that reline or rebase procedures did notThis study demonstrated that reline or rebase procedures did not
cause clinically significant.cause clinically significant.

CLINICAL IMPRESSION PROCEDURESCLINICAL IMPRESSION PROCEDURES
FOR RELINING OR REBASINGFOR RELINING OR REBASING
► The Static Impression Technique. Closed-mouth techniqueThe Static Impression Technique. Closed-mouth technique
Open-mouth techniqueOpen-mouth technique
► The Functional Impression Technique.The Functional Impression Technique.
► The Chairside Technique.The Chairside Technique.

Closed-mouth relining techniques- maxillary dentureClosed-mouth relining techniques- maxillary denture:-:-
- Dentures are used as impression trays.- Dentures are used as impression trays.
- Either the existing centric relation occlusion is used to seat the- Either the existing centric relation occlusion is used to seat the
dentures with lining impression material or a new centric relation isdentures with lining impression material or a new centric relation is
recorded with impression compound before impressions are made.recorded with impression compound before impressions are made.
Some closed-mouth techniques are:-Some closed-mouth techniques are:-

Technique A:-Technique A:- Shafer F.H and Miller W.H(1971)Shafer F.H and Miller W.H(1971)
Centric Relation:-Centric Relation:- Centric relation is recorded before the impression isCentric relation is recorded before the impression is
made, using modeling compound or wax.made, using modeling compound or wax.
Denture Preparation:-Denture Preparation:- Denture is prepared before making theDenture is prepared before making the
impression by relieving all large undercuts and by relieving 1.5-2mmimpression by relieving all large undercuts and by relieving 1.5-2mm
from the tissue surface. The borders are reduced 1-2mm except thefrom the tissue surface. The borders are reduced 1-2mm except the
posterior border of maxillary dentures.posterior border of maxillary dentures.
Special Suggestion:-Special Suggestion:- A large part of the middle of the palatal portion ofA large part of the middle of the palatal portion of
the maxillary denture is removed for visibility in positioning thethe maxillary denture is removed for visibility in positioning the
maxillary denture during the impression making.maxillary denture during the impression making.
Border Molding:-Border Molding:- The borders of the dentures are reformed to theirThe borders of the dentures are reformed to their
functional contours by using low-fusing modeling compound.functional contours by using low-fusing modeling compound.
Impression:-Impression:- ZOE impression paste.ZOE impression paste.
During border molding and impression making, the patient closesDuring border molding and impression making, the patient closes
lightly into the pre-made interocclusal record.lightly into the pre-made interocclusal record.
The impression of the exposed part of the palatal section is madeThe impression of the exposed part of the palatal section is made
with quick-setting plaster.with quick-setting plaster.

Advantages:-Advantages:-
1) The opening of the palatal portion will allow better seating of the1) The opening of the palatal portion will allow better seating of the
maxillary denture and alleviate the increase in vertical dimensionmaxillary denture and alleviate the increase in vertical dimension
pitfall.pitfall.
2) The pre-made interocclusal record helps to position the dentures2) The pre-made interocclusal record helps to position the dentures
during the impression making and to orient the dentures on theduring the impression making and to orient the dentures on the
articulator.articulator.
3) The two-step impression technique will reduce the possibility of3) The two-step impression technique will reduce the possibility of
moving the maxillary denture forward during the final impressionmoving the maxillary denture forward during the final impression
making.making.
Disadvantages:-Disadvantages:-
1) The possibility of moving the maxillary denture forward is still a1) The possibility of moving the maxillary denture forward is still a
major problem.major problem.
2) The wax interocclusal record is not an accurate and safe record that2) The wax interocclusal record is not an accurate and safe record that
the patient can close on several times without the possibility ofthe patient can close on several times without the possibility of
damaging the record.damaging the record.
3) This technique does not suggest any solution for difficulties of3) This technique does not suggest any solution for difficulties of
relining both dentures at the same time.relining both dentures at the same time.www.indiandentalacademy.com

Technique B:-Technique B:- Hansen N.J(1964)Hansen N.J(1964)
Centric Relation:-Centric Relation:- Existing centric occlusion and intercuspation areExisting centric occlusion and intercuspation are
used to seat the dentures.used to seat the dentures.
Denture Preparation:-Denture Preparation:-
Special Suggestion:-Special Suggestion:- A large part of the palatal section is prepared toA large part of the palatal section is prepared to
be removed as follows:-be removed as follows:-
First, the outline of the area should be indicated and deepened on theFirst, the outline of the area should be indicated and deepened on the
polished surface up to half the thickness of the base.polished surface up to half the thickness of the base.
Holes are drilled at 5-6mm intervals inside this groove.Holes are drilled at 5-6mm intervals inside this groove.
This procedure is suggested for easy removal of the palatal portionThis procedure is suggested for easy removal of the palatal portion
during packing and processing.during packing and processing.
Border Molding:-Border Molding:- Low-fusing modeling compound(green stick).Low-fusing modeling compound(green stick).
Impression:-Impression:- Wax that flows at mouth temperature, such as Kerr’sWax that flows at mouth temperature, such as Kerr’s
impression wax(Iowa wax) – material of choice.impression wax(Iowa wax) – material of choice.
Impression is made in two steps:-Impression is made in two steps:-
- Impression of the labial flange- Impression of the labial flange
- Crest of the alveolar ridge between the canines.- Crest of the alveolar ridge between the canines.www.indiandentalacademy.com

Advantage:-Advantage:-
Two-step impression technique will reduce the possibility of extremeTwo-step impression technique will reduce the possibility of extreme
forward movement of the maxillary dentures.forward movement of the maxillary dentures.
Disadvantage:-Disadvantage:-
1) Wax impression material is difficult to work with and the possibility1) Wax impression material is difficult to work with and the possibility
of distortion exists.of distortion exists.
2) Errors of existing centric occlusion can produce an inaccurate2) Errors of existing centric occlusion can produce an inaccurate
impression.impression.

Technique C:-Technique C:- Christensen F.T(1971)Christensen F.T(1971)
Centric Relation:-Centric Relation:- Existing centric occlusion and intercuspation.Existing centric occlusion and intercuspation.
Denture Preparation:-Denture Preparation:-
Special Suggestions:-Special Suggestions:- The labial and palatal flanges of the denture areThe labial and palatal flanges of the denture are
perforated, perforations will decrease the pressure inside the dentureperforated, perforations will decrease the pressure inside the denture
during impression-making preventing displacement of maxillaryduring impression-making preventing displacement of maxillary
denture.denture.
Border Molding:-Border Molding:- Low-fusing modeling compoundLow-fusing modeling compound
Impression:-Impression:- No specific impression material recommended.No specific impression material recommended.
Disadvantage:-Disadvantage:- Increase in vertical dimension of occlusion duringIncrease in vertical dimension of occlusion during
laboratory procedures.laboratory procedures.

Technique D:-Technique D:- Jordan L.G(1972)Jordan L.G(1972)
Centric Relation:-Centric Relation:- Existing centric occlusion.Existing centric occlusion.
Specific Suggestions:-Specific Suggestions:-
1) Denture periphery should be shortened to create a flat border.1) Denture periphery should be shortened to create a flat border.
2) A large opening should be prepared in the palatal portion of the2) A large opening should be prepared in the palatal portion of the
maxillary denture.maxillary denture.
3) Adhesive tape is attached over the buccal and labial surfaces of3) Adhesive tape is attached over the buccal and labial surfaces of
both dentures 2mm away from the denture borders.both dentures 2mm away from the denture borders.
4) With a knife-edge stone, a fairly deep groove should be cut into the4) With a knife-edge stone, a fairly deep groove should be cut into the
buccal and labial surfaces of the dentures at the junction of thebuccal and labial surfaces of the dentures at the junction of the
impression material and filled with molten baseplate wax.impression material and filled with molten baseplate wax.
Border Molding:-Border Molding:- Not suggested, but slight amount of impressionNot suggested, but slight amount of impression
material should be left on the flattened borders during impressionmaterial should be left on the flattened borders during impression
making.making.

Impression:-Impression:- Plaster of Paris or zinc oxide eugenol for first step ofPlaster of Paris or zinc oxide eugenol for first step of
impression making, and plaster of Paris for second step(palatalimpression making, and plaster of Paris for second step(palatal
portion).portion).
Disadvantages:-Disadvantages:- Even though it has been suggested that the patientEven though it has been suggested that the patient
should not seat the denture by closing on it, the existing errors ofshould not seat the denture by closing on it, the existing errors of
centric occlusion may produce some pressure points and a faultycentric occlusion may produce some pressure points and a faulty
impression can result.impression can result.

Closed-mouth relining technique- mandibular denture:-Closed-mouth relining technique- mandibular denture:-
Factors to be considered during the relining of a mandibular dentureFactors to be considered during the relining of a mandibular denture
are :are :
Ridge relation, ridge form and the characteristics of the mucosaRidge relation, ridge form and the characteristics of the mucosa
covering the ridges.covering the ridges.
Technique E:-Technique E:- Gillis R.R(1960)Gillis R.R(1960)
Centric Relation:-Centric Relation:- Existing centric occlusion used to seat dentures.Existing centric occlusion used to seat dentures.
Special Suggestion:-Special Suggestion:-
1) Loss of vertical dimension corrected by luting softened modeling1) Loss of vertical dimension corrected by luting softened modeling
compound to the occlusal surfaces of the mandibular posterior teeth.compound to the occlusal surfaces of the mandibular posterior teeth.
2) Patient asked to repeatedly pronounce letter “m.”2) Patient asked to repeatedly pronounce letter “m.”
3) Record is chilled, trimmed and slightly heated before returning to3) Record is chilled, trimmed and slightly heated before returning to
the patient’s mouth. Repeat procedure until correct occlusal verticalthe patient’s mouth. Repeat procedure until correct occlusal vertical
dimension is established.dimension is established. www.indiandentalacademy.com

4) Lower working impression made and poured and lower denture4) Lower working impression made and poured and lower denture
mounted on an articulator.mounted on an articulator.
5) Denture removed and cleaned and excessive undercuts removed5) Denture removed and cleaned and excessive undercuts removed
and is luted to the maxillary denture in maximum intercuspation.and is luted to the maxillary denture in maximum intercuspation.
6) Softened modeling compound is placed inside the mandibular6) Softened modeling compound is placed inside the mandibular
denture and the articulator closed against the lower cast to contactdenture and the articulator closed against the lower cast to contact
the incisal guide pin.the incisal guide pin.
7) With this procedure, the amount of vertical dimension indicated by7) With this procedure, the amount of vertical dimension indicated by
the thickness of the compound on the surface of the mandibular teeththe thickness of the compound on the surface of the mandibular teeth
is transferred to the base of the mandibular denture.is transferred to the base of the mandibular denture.
8) Mandibular denture now is used as a tray for making the final8) Mandibular denture now is used as a tray for making the final
impression.impression.
Impression:-Impression:- Modeling compound at early stage.Modeling compound at early stage.
Zinc oxide-eugenol for secondary impression.Zinc oxide-eugenol for secondary impression.

Advantages:-Advantages:-
1) The loss of vertical dimension can be compensated for during1) The loss of vertical dimension can be compensated for during
relining procedures.relining procedures.
2) The error in centric occlusion can be reduced during the laboratory2) The error in centric occlusion can be reduced during the laboratory
stages.stages.
1) Time consuming.1) Time consuming.
2) The procedure for establishment of occlusal vertical dimension is2) The procedure for establishment of occlusal vertical dimension is
questionable.questionable.

Open-mouth impression technique:-Open-mouth impression technique:-
- Given by Boucher.- Given by Boucher.
- Only technique that describes a method for relining the mandibular- Only technique that describes a method for relining the mandibular
and maxillary dentures at the same time.and maxillary dentures at the same time.
- Impressions are made independently, without utilizing the existing- Impressions are made independently, without utilizing the existing
centric occlusion and a new centric relation record is established.centric occlusion and a new centric relation record is established.

Technique F:-Technique F:- Boucher C.O.(1973)Boucher C.O.(1973)
Centric relation:-Centric relation:- Dentures used as record bases and jaw relationsDentures used as record bases and jaw relations
recorded after making secondary impressions.recorded after making secondary impressions.
Denture Preparation:-Denture Preparation:- Posterior palatal seal is formed in modelingPosterior palatal seal is formed in modeling
compound before any changes made on tissue side of denture. 1mmcompound before any changes made on tissue side of denture. 1mm
space is provided inside the denture for new impression material andspace is provided inside the denture for new impression material and
the borders are shortened by 1mm to allow space for new impressionthe borders are shortened by 1mm to allow space for new impression
material to form a new border.material to form a new border.
Special Suggestion:-Special Suggestion:-
1) Denture prepared for reline impression.1) Denture prepared for reline impression.
2) Buccal surfaces of the lingual flanges are ground to minimise the2) Buccal surfaces of the lingual flanges are ground to minimise the
pressure against the mylohyoid ridges and between the tissues of thepressure against the mylohyoid ridges and between the tissues of the
floor of the mouth and the buccal sides of the lingual flangesfloor of the mouth and the buccal sides of the lingual flanges
3) The lingual flange between the premylohyoid eminences and labial3) The lingual flange between the premylohyoid eminences and labial
flange between the buccal notches are shortened by 1mm.flange between the buccal notches are shortened by 1mm.
4) A modeling compound handle is formed over the lower anterior teeth4) A modeling compound handle is formed over the lower anterior teeth
and an adhesive or masking tape is adapted over the polishedand an adhesive or masking tape is adapted over the polished
surfaces of both dentures and over the teeth.surfaces of both dentures and over the teeth.www.indiandentalacademy.com

Border Molding:-Border Molding:- If inadequate flanges- borders should be correctedIf inadequate flanges- borders should be corrected
with modelling compound.with modelling compound.
Impression:-Impression:- Zinc oxide-eugenol impression material.Zinc oxide-eugenol impression material.
- 15 seconds after the denture has been placed in the mouth, the- 15 seconds after the denture has been placed in the mouth, the
patient is asked to pull his upper lip down and open his mouth wide.patient is asked to pull his upper lip down and open his mouth wide.
This molds the impression material over the borders of the denture.This molds the impression material over the borders of the denture.
Advantages:-Advantages:- 1) The special trimming of the denture and making room1) The special trimming of the denture and making room
for the impression material will facilitate the making of a reasonablefor the impression material will facilitate the making of a reasonable
impression during the selective pressure impression techniqueimpression during the selective pressure impression technique
without any occlusal interference.without any occlusal interference.
2) A separate interocclusal record using already made impressions as2) A separate interocclusal record using already made impressions as
the recording bases will allow the operator to concentrate onthe recording bases will allow the operator to concentrate on
recording the jaw relation.recording the jaw relation.
3) It is possible to verify the centric relation record if necessary.3) It is possible to verify the centric relation record if necessary.
4) Interocclusal record, made with quick setting plaster, is a reliable4) Interocclusal record, made with quick setting plaster, is a reliable
one.one.
Disadvantages:-Disadvantages:- 1) This technique requires more clinical and1) This technique requires more clinical and
laboratory time and the performance of the procedures is not easy.laboratory time and the performance of the procedures is not easy.www.indiandentalacademy.com

2)2) Functional Impression Technique:-Functional Impression Technique:-
► It depends upon the thorough understanding of the versatile
properties of tissue conditioners as functional impression materials.
► Improvements in these materials includes their retaining compliance
for many weeks, their good dimensional stability and their excellent
bonding to denture base.
► Soft tissues should be assessed first for hyperemia and denture for its
compound may be needed before the placement of fresh mix of linercompound may be needed before the placement of fresh mix of liner
as these materials have a tendency to slump during setting and lessas these materials have a tendency to slump during setting and less
they are adequately supported.they are adequately supported.
► The patients mandible guided to retruded position which is one ofThe patients mandible guided to retruded position which is one of
maximum intercuspation (centric occlusion) to help stabilize themaximum intercuspation (centric occlusion) to help stabilize the
denture while the lining material is setting.denture while the lining material is setting.
► Excess material is trimmed with hot scalpel.Excess material is trimmed with hot scalpel.

3) Chairside Technique:-3) Chairside Technique:-
- Cold cure acrylic is added to the denture and allowed to- Cold cure acrylic is added to the denture and allowed to
polymerize in the mouth to produce an instant chairsidepolymerize in the mouth to produce an instant chairside
reline/rebase.reline/rebase.
1) The materials often produce a chemical burn on the mucosa.1) The materials often produce a chemical burn on the mucosa.
2) The result often was porous and developed a bad odour.2) The result often was porous and developed a bad odour.
3) Colour stability was poor.3) Colour stability was poor.
4) If the denture was not positioned correctly, the material could4) If the denture was not positioned correctly, the material could
not be removed easily to start again.not be removed easily to start again.

LABORATORY PROCEDURE FOR RELININGLABORATORY PROCEDURE FOR RELINING
► ARTICULATOR METHOD:-ARTICULATOR METHOD:-
Impression is made in theImpression is made in the
denture to be relined.denture to be relined.
Denture impression isDenture impression is
poured in dental stone.poured in dental stone.

Modeling clay adapted denture,Modeling clay adapted denture,
blocking out all the dentureblocking out all the denture
surfaces,except occlusal surfaces ofsurfaces,except occlusal surfaces of
the teeth.the teeth.
Stone is placed on the lowerStone is placed on the lower
member and smoothed withmember and smoothed with
spatula. Denture is settled isspatula. Denture is settled is
the stone mix.the stone mix.

Cast is attached to the upper member of theCast is attached to the upper member of the
articulator with dental stone.articulator with dental stone.
Modeling clay removed fromModeling clay removed from
denture surface.denture surface.

All impression material must be removedAll impression material must be removed
from the denture.from the denture.
Thin layer of resin must be removedThin layer of resin must be removed
from the inferior of the denturefrom the inferior of the denture
with the acrylic bur.with the acrylic bur.

Borders are reduced 2-3mm with bur.Borders are reduced 2-3mm with bur.
Frena notches are deepened withFrena notches are deepened with
no.557 cross-cut fissure bur.no.557 cross-cut fissure bur.

Resin grindings removed withResin grindings removed with
stream of air.stream of air.
Posterior palatal seal is placed in the cast,Posterior palatal seal is placed in the cast,
unless provided in impression.unless provided in impression.

Paint cast with tinfoil substitute.Paint cast with tinfoil substitute.
Mix autopolymerizing resin and place inMix autopolymerizing resin and place in
denture. Avoid air entrapment.denture. Avoid air entrapment.

Place resin on cast and in border reflectionsPlace resin on cast and in border reflections
Denture is seated in indentations,Denture is seated in indentations,
and articulator closed.and articulator closed.

Relined denture cured in pressure containerRelined denture cured in pressure container
at 15-20psi for 30min.at 15-20psi for 30min.
Relined denture removedRelined denture removed
and examined for voids andand examined for voids and
nodules.nodules.
Finished and polished.Finished and polished.

LABORATORY PROCEDURE FORLABORATORY PROCEDURE FOR
REBASINGREBASING
► JIG METHOD:-JIG METHOD:-
Stone index formed on lower member
of duplicator or jig.
Denture mounted on its cast in a reline jig
with stone and secured with locknuts

Porcelain denture teeth are removed from denture byPorcelain denture teeth are removed from denture by
heating with alcohol torch or hot spatula.heating with alcohol torch or hot spatula.

Porcelain teeth replaced in theirPorcelain teeth replaced in their
indentations in the stone indexindentations in the stone index
Adapt a layer of base plate wax to castAdapt a layer of base plate wax to cast
and assemble the jigand assemble the jig

Wax-up the denture teeth to base plate wax,Wax-up the denture teeth to base plate wax,
remove cast, flask and process withremove cast, flask and process with
heat cure denture base resin.heat cure denture base resin.
Cured denture replaced on jig to checkCured denture replaced on jig to check
occlusion, then finished and polished.occlusion, then finished and polished.

► FLASK METHOD:-FLASK METHOD:-
Denture is half flaskedDenture is half flasked
Silicone mold material paintedSilicone mold material painted
on denture and teeth.on denture and teeth.

Flask is opened.Flask is opened.
Porcelain teeth Resin teethPorcelain teeth Resin teeth

Cast and investing stone paintedCast and investing stone painted
with tinfoil substitutewith tinfoil substitute
Cured denture ready forCured denture ready for
finishing and polishing.finishing and polishing.

REPAIR OF COMPLETE DENTUREREPAIR OF COMPLETE DENTURE

► Complete dentures often fractures when in function or whenComplete dentures often fractures when in function or when
dropped onto a hard surface.dropped onto a hard surface.
► The most common denture fractures are those along the maxillaryThe most common denture fractures are those along the maxillary
and mandibular midline.and mandibular midline.
► The repair of dentures is a difficult part of prosthesis, which can beThe repair of dentures is a difficult part of prosthesis, which can be
often handled as a laboratory procedure, but a knowledge ofoften handled as a laboratory procedure, but a knowledge of
preparation as well as the technical phase is essential for successfulpreparation as well as the technical phase is essential for successful
repair.repair.

CAUSES OF FRACTURE OF DENTURECAUSES OF FRACTURE OF DENTURE
1)1) FRACTURE OF THE DENTURE BASE
► Improper mandibular occlusal plane
A common problem is the recurrent midline fracture in maxillary
complete denture opposing natural dentition. Uneven or deflective
occlusal plane leads to defective occlusal contacts which deform the
denture base and create a line of fatigue that results in a denture
base fracture.
► High frenum attachments:
A broad maxillary labial frenum that is attached close to the crest
of the ridge requires to be provided with relief during function,
which results in a deep notch, and weakens the denture base, and it
causes concentration of stress at that point and may lead to site of
commencement of fracture.
► Occlusal morphology:
Bilateral balanced occlusion is ideal for the denture stability.
Incorrect recording of occlusion, absence of balanced occlusion will
results in abnormal stress being applied to the denture base during
function (which causes midline fracture).www.indiandentalacademy.com

► Occlusal forces:Occlusal forces:
A low Frankfort mandibular plane angle (FMA) leads to increasedA low Frankfort mandibular plane angle (FMA) leads to increased
amount of occlusal forces to the underlying residual ridge which mayamount of occlusal forces to the underlying residual ridge which may
contribute to the increased incidence of denture base fracture.contribute to the increased incidence of denture base fracture.
Patients with an increased vertical dimension at occlusion are pronePatients with an increased vertical dimension at occlusion are prone
to denture base fracture due to the excessive masticatory forces.to denture base fracture due to the excessive masticatory forces.
Beyli M.S. (1981)Beyli M.S. (1981) concluded that midline fracture of a denture baseconcluded that midline fracture of a denture base
was a flexural fatigue failure resulting from cyclic deformation of thewas a flexural fatigue failure resulting from cyclic deformation of the
denture base during function. Buccally arranged upper posterior teethdenture base during function. Buccally arranged upper posterior teeth
to the crest of the ridge will transmit flexing component of forces toto the crest of the ridge will transmit flexing component of forces to
the midline of the denture during function and leads to midlinethe midline of the denture during function and leads to midline
fracture.fracture.

► Denture base thickness:Denture base thickness:
Insufficient thickness of the denture base lingual to incisal resultingInsufficient thickness of the denture base lingual to incisal resulting
from improper waxing is heavily stressed under function and leadsfrom improper waxing is heavily stressed under function and leads
to midline fracture.to midline fracture.
The denture lined with resilient denture base liners are moreThe denture lined with resilient denture base liners are more
susceptible for fracture due to excessive reduction of the denturesusceptible for fracture due to excessive reduction of the denture
base to allow the space for liner material will result in thinning ofbase to allow the space for liner material will result in thinning of
denture base and prone for fracture.denture base and prone for fracture.
► Inaccurate Relief:-Inaccurate Relief:-
Self relieving impression technique has been employed, such asSelf relieving impression technique has been employed, such as
compression impression technique, usually in mouths exhibitingcompression impression technique, usually in mouths exhibiting
gross variations in the thickness of the mucous membrane thegross variations in the thickness of the mucous membrane the
denture will flex over the hard areas of the palate and causesdenture will flex over the hard areas of the palate and causes
fracture.fracture.

► Stress Concentrators:-Stress Concentrators:-
Changes in surface profiles of denture acting as stress concentratorsChanges in surface profiles of denture acting as stress concentrators
include –Scratches, a median diastema, deep frenal notch weakensinclude –Scratches, a median diastema, deep frenal notch weakens
the dentures and cause concentration of stress & lead to site ofthe dentures and cause concentration of stress & lead to site of
commencement of fracture.commencement of fracture.
► Absence of Labial Flange:-Absence of Labial Flange:-
An open face denture is not as stiff as a flanged denture. Flexing willAn open face denture is not as stiff as a flanged denture. Flexing will
be more marked and is likely to result in fatigue fracture.be more marked and is likely to result in fatigue fracture.
► Incomplete Polymerization of Acrylic Resin:-Incomplete Polymerization of Acrylic Resin:-
If the curing cycle does not include a terminal heating period atIf the curing cycle does not include a terminal heating period at
100ºC, the maximum degree of polymerization is not attained and the100ºC, the maximum degree of polymerization is not attained and the
strength of denture base will be reduced.strength of denture base will be reduced.
Packing the acrylic resin in advanced dough stage will leads toPacking the acrylic resin in advanced dough stage will leads to
fractured or dislodged teeth in the complete denture.fractured or dislodged teeth in the complete denture.

► Previous Repair:-Previous Repair:-
When fractured previously in midline and repaired by cold cure acrylicWhen fractured previously in midline and repaired by cold cure acrylic
resin – more susceptible to fatigue.resin – more susceptible to fatigue.
► Shape of the Teeth on the Denture:-Shape of the Teeth on the Denture:-
Because of wear, a wedging action on the upper denture results fromBecause of wear, a wedging action on the upper denture results from
occlusion of teeth and locking of occlusion also appears to predisposeocclusion of teeth and locking of occlusion also appears to predispose
midline fracture.midline fracture.
► Overdenture abutment too prominent:-Overdenture abutment too prominent:-
will result in inadequate thickness in denture base. A patient with anwill result in inadequate thickness in denture base. A patient with an
overdenture can exert more occlusal force.overdenture can exert more occlusal force.

BREAKAGE OF A TOOTH OR TEETHBREAKAGE OF A TOOTH OR TEETH
► Cuspal Interference:-Cuspal Interference:-
Is confined to one tooth or teeth, in cases where the pressure isIs confined to one tooth or teeth, in cases where the pressure is
heavier on one tooth than elsewhere, it will frequently cause the toothheavier on one tooth than elsewhere, it will frequently cause the tooth
to split.to split.
An anterior tooth may be broken off if there is excessive overbite withAn anterior tooth may be broken off if there is excessive overbite with
insufficient overjet.insufficient overjet.
► Faulty Tooth:-Faulty Tooth:-
Entirely confined to anterior porcelain pin teeth and an undetectedEntirely confined to anterior porcelain pin teeth and an undetected
flaw in the porcelain usually results in the tooth breaking across theflaw in the porcelain usually results in the tooth breaking across the
line of the pins.line of the pins.

► Contraction of Acrylic Resin:-Contraction of Acrylic Resin:-
May be a cause of fracture in porcelain teeth set in an acrylic base.May be a cause of fracture in porcelain teeth set in an acrylic base.
It is due to large and uneven contraction of acrylic resin whichIt is due to large and uneven contraction of acrylic resin which
occurs during polymerization, inducing excessive stresses in theoccurs during polymerization, inducing excessive stresses in the
porcelain teeth.porcelain teeth.
► Excessive Grinding of a Tooth:-Excessive Grinding of a Tooth:-
Excessive grinding of either the occlusal or ridge surface of aExcessive grinding of either the occlusal or ridge surface of a
porcelain posterior tooth to weaken it, as to causes fracture.porcelain posterior tooth to weaken it, as to causes fracture.

MATERIALS USED FOR DENTURE REPAIRMATERIALS USED FOR DENTURE REPAIR
► Despite the favorable physical characteristics of the denture baseDespite the favorable physical characteristics of the denture base
resins, denture bases sometimes fracture.resins, denture bases sometimes fracture.
► In most instances such fractures may be repaired using compatibleIn most instances such fractures may be repaired using compatible
resins.resins.
► These materials usually available in powder: liquid type similar toThese materials usually available in powder: liquid type similar to
those used for denture bases and are either heat activated orthose used for denture bases and are either heat activated or
chemically activated.chemically activated.
► Now, light activated acrylic resins have been shown to be fast andNow, light activated acrylic resins have been shown to be fast and
effective denture repair materials.effective denture repair materials.

Carbon Fibers:-Carbon Fibers:-
► Conventional dentures are reinforced by inclusions of carbon fiberConventional dentures are reinforced by inclusions of carbon fiber
inserts in the palate to reduce the flexibility of denture base.inserts in the palate to reduce the flexibility of denture base.
► Advantages:-Advantages:-
It reduces the incidence of fracture.It reduces the incidence of fracture.
Increases transverse and impact strength of poly methylIncreases transverse and impact strength of poly methyl
methacrylate.methacrylate.
Black colour.Black colour.

Ultra-high-modulus Polyethylene Fibers (UHMPE):-Ultra-high-modulus Polyethylene Fibers (UHMPE):-
► This material may be added either as a discrete woven insert into theThis material may be added either as a discrete woven insert into the
denture base or as chopped fiber incorporated in the polymer powderdenture base or as chopped fiber incorporated in the polymer powder
before the resin is mixed.before the resin is mixed.
► The fiber is transparent and its inclusion in the polymer as choppedThe fiber is transparent and its inclusion in the polymer as chopped
fiber at a loading of 1% has resulted in an increase in impact strengthfiber at a loading of 1% has resulted in an increase in impact strength
exceeding that of commercially available “high impact” resins.exceeding that of commercially available “high impact” resins.
► When the material is inserted as a woven mat loadings of 20-30% areWhen the material is inserted as a woven mat loadings of 20-30% are
reported.reported.

Glass Fibers:-Glass Fibers:-
► Inclusions of glass fibers into acrylic resin has shown to improveInclusions of glass fibers into acrylic resin has shown to improve
fatigue resistance, flexural strength and impact strength.fatigue resistance, flexural strength and impact strength.
► The fibers are produced either as a woven mat and inserted into theThe fibers are produced either as a woven mat and inserted into the
whole denture, or as individual fibers which are laid out in the regionwhole denture, or as individual fibers which are laid out in the region
of a previous weakness.of a previous weakness.
► To obtain full benefit, care must be taken to position the fibersTo obtain full benefit, care must be taken to position the fibers
correctly.correctly.
► Enhances flexural properties of multi phase dental polymer, whichEnhances flexural properties of multi phase dental polymer, which
is due to proper impregnation of fibers with polymer matrix.is due to proper impregnation of fibers with polymer matrix.
► Composition: SiOComposition: SiO22- 55% H- 55% H22OO33- 15%- 15%
CaO- 22% BCaO- 22% B22OO33- 6%- 6%

SELECTION OF EDGE PROFIL FOR REPAIRSELECTION OF EDGE PROFIL FOR REPAIR
► Harrison & StansburyHarrison & Stansbury(1970)(1970) investigated the strength of dentureinvestigated the strength of denture
repairs using,repairs using,
A) Round JointA) Round Joint
B) Rabbet JointB) Rabbet Joint
C) Butt JointC) Butt Joint
They concluded that rounded joint was superior to the rabbet and buttThey concluded that rounded joint was superior to the rabbet and butt
joints and it supports the principle that sharp angled surfaces promotejoints and it supports the principle that sharp angled surfaces promote
stress concentrations and the amount of stress concentration is directlystress concentrations and the amount of stress concentration is directly
related to the degree and abruptness of surface change.related to the degree and abruptness of surface change.www.indiandentalacademy.com

► Beyli et al(Beyli et al(1980)1980) conducted a study on the “repair of fractured acrylicconducted a study on the “repair of fractured acrylic
resin” and said that the criteria for satisfactory repair are:-resin” and said that the criteria for satisfactory repair are:-
Repair must be rapid.Repair must be rapid.
Repaired structures must have adequate strength.Repaired structures must have adequate strength.
Denture must retain dimensional accuracy during and afterDenture must retain dimensional accuracy during and after
repairs.repairs.
► Initial studies indicated that a 3mm gap width was suitable for repairInitial studies indicated that a 3mm gap width was suitable for repair
and seven different edge profiles were prepared at this gap width:-and seven different edge profiles were prepared at this gap width:-
i) Knife edgei) Knife edge
ii) Inverse knife edgeii) Inverse knife edge
iii) Roundiii) Round
iv) Lapiv) Lap
v) Rabbetv) Rabbet
vi) Inverse Rabbetvi) Inverse Rabbet
vii) Ogeevii) Ogee

► They concluded that traditional butt joint for repair of fracturedThey concluded that traditional butt joint for repair of fractured
dentures has been found to be inferior to the inverse knife edge, rounddentures has been found to be inferior to the inverse knife edge, round
lap, inverse rabbet and ogee joints.lap, inverse rabbet and ogee joints.
► The round joint appears to be the most convenient in practice becauseThe round joint appears to be the most convenient in practice because
of its easy preparation.of its easy preparation.
► The gap size should be 3mm or less to minimize the bulk of repairThe gap size should be 3mm or less to minimize the bulk of repair
material used which will reduce any colour differences.material used which will reduce any colour differences.
► A lower bulk of repair material will decrease the degree of shrinkageA lower bulk of repair material will decrease the degree of shrinkage

METHODS FOR REPAIRMETHODS FOR REPAIR
► Anterior Tooth Replacement:-Anterior Tooth Replacement:-
Fractured tooth isFractured tooth is
removed by grindingremoved by grinding
with no. 8 round bur.with no. 8 round bur.
Care must be taken notCare must be taken not
to perforate dentureto perforate denture
base.base.
Labial gingival margin shouldLabial gingival margin should
be left intact to preservebe left intact to preserve
esthetics.esthetics.

Remove the resin from the lingualRemove the resin from the lingual
aspect of the denture baseaspect of the denture base
Select a resin toothSelect a resin tooth
of same size andof same size and
shade and grind itsshade and grind its
ridge lap for properridge lap for proper
positioning on thepositioning on the
denture.denture.

Verify the tooth position and secure it in
position with sticky wax.
If the tooth position is
acceptable, pour a
plaster index or silicone
index onto the labial
surface of the tooth to
be replaced and on the
labial surfaces of adjoining teeth on each side.www.indiandentalacademy.com

After plaster sets, the index and toothAfter plaster sets, the index and tooth
are separated and sticky wax removed.are separated and sticky wax removed.
Shallow indentations can beShallow indentations can be
placed in the ridge laps of theplaced in the ridge laps of the
tooth with a no. 6 bur to ensuretooth with a no. 6 bur to ensure
stronger repair.stronger repair. www.indiandentalacademy.com

Replace the index andReplace the index and
tooth on the denture,tooth on the denture,
and carefully paint theand carefully paint the
autopolymerizing resinautopolymerizing resin
to the lingual or palatalto the lingual or palatal
prepared area,prepared area,
allowing the resin to flow betweenallowing the resin to flow between
ridge lap and denture base.ridge lap and denture base.
Resin is added to build up slightResin is added to build up slight
excess, which will be finished toexcess, which will be finished to
original contour after polymerizing.original contour after polymerizing.

Repaired denture is placed in a pressure pot of warm water, andRepaired denture is placed in a pressure pot of warm water, and
cured at 20 psi for 30min.cured at 20 psi for 30min.

Remove the denture, and reduce the excess bulk with no. 8 bur and
resin is smoothed with mounted rubber point and repair is polished
with flour of pumice & handpiece mounted prophy cup.

► Posterior Tooth Replacement:-Posterior Tooth Replacement:-
Mount the denture in an articulatorMount the denture in an articulator
Remove the fractured resin tooth by grinding it with a no. 8 roundRemove the fractured resin tooth by grinding it with a no. 8 round
bur. Take care tobur. Take care to
preserve the facialpreserve the facial
gingival margin ofgingival margin of
the denture base andthe denture base and
not to perforate thenot to perforate the
base.base.

Ridge lap area ofRidge lap area of
denture is hollow grounddenture is hollow ground
and of the replacementand of the replacement
tooth is modified for thetooth is modified for the
correct placement ofcorrect placement of
tooth.tooth.
Close the articulatorClose the articulator
and check the occlusion.and check the occlusion.
If correct, seal theIf correct, seal the
replacement tooth toreplacement tooth to
opposing tooth withopposing tooth with
sitcky wax.sitcky wax.

Paint the autopolymerising resin into thePaint the autopolymerising resin into the
ridge lap area to seal the tooth to theridge lap area to seal the tooth to the
denture base.denture base.

Place the denture in a pressure container of warm water, and cure it for 30min. atPlace the denture in a pressure container of warm water, and cure it for 30min. at
20 psi. Adjust the occlusion and polish the repair.20 psi. Adjust the occlusion and polish the repair.www.indiandentalacademy.com

► Repairing Fractured Denture:-Repairing Fractured Denture:-
( Non-separated Fracture)( Non-separated Fracture)
Examine denture to determine theExamine denture to determine the
extent of the fracture. Gently flexingextent of the fracture. Gently flexing
denture will aid this determination, butdenture will aid this determination, but
take care to prevent breakage.take care to prevent breakage.
If fractured denture self-approximates,If fractured denture self-approximates,
block the undercuts with clay,block the undercuts with clay,
and pour the repair cast.and pour the repair cast.

Full cast is not necessary if theFull cast is not necessary if the
fracture is small.fracture is small.
If undercut is there inIf undercut is there in
the region of repair,the region of repair,
silicone mold materialsilicone mold material
can be placed in thecan be placed in the
undercut, resulting inundercut, resulting in
flexible cast permittingflexible cast permitting
removal of denture,removal of denture, www.indiandentalacademy.com

Remove the denture from the cast, andRemove the denture from the cast, and
widen the fracture line from beginningwiden the fracture line from beginning
to end with no. 558 bur.to end with no. 558 bur.
Widened cut is beveled outwardsWidened cut is beveled outwards
to increase bonding area.to increase bonding area.

Dovetails can be placed on theDovetails can be placed on the
palatal surface to further strengthenpalatal surface to further strengthen
repair joint.repair joint.
Paint the stone cast with tinfoilPaint the stone cast with tinfoil
substitute and allow it to dry. If notsubstitute and allow it to dry. If not
completely dry then the resin maycompletely dry then the resin may
be coated, reducing repair strength.be coated, reducing repair strength.

Denture is replaced on the castDenture is replaced on the cast
carefully.carefully.
Repair resin is painted in groove,Repair resin is painted in groove,
taking care not to create voids.taking care not to create voids.

Excess resin is built up Denture is secured to theExcess resin is built up Denture is secured to the
for finishing cast with a rubber band, andfor finishing cast with a rubber band, and
cured in a pressure containercured in a pressure container
for 30 min.for 30 min.
Cured denture is removed, finished and polishedwww.indiandentalacademy.com

► Denture Fractured into Two or More PartsDenture Fractured into Two or More Parts
Examine the denture to determine that all pieces are present.Examine the denture to determine that all pieces are present.
Assemble the pieces and lute them with sticky wax.Assemble the pieces and lute them with sticky wax.www.indiandentalacademy.com

Modeling clay can be used to hold pieces while luting denture with sticky wax andModeling clay can be used to hold pieces while luting denture with sticky wax and
reinforcing with wood sticks before removing from clay.reinforcing with wood sticks before removing from clay.

Alginate can be usedAlginate can be used
inin
pronounced undercutspronounced undercuts
in mandibular denture.in mandibular denture.

Remove theRemove the
denturedenture
from the cast. Bevel thefrom the cast. Bevel the
margins of each fragmentmargins of each fragment
with bur and make grooveswith bur and make grooves
and dovetail. Use wireand dovetail. Use wire
reinforcement toreinforcement to
strengthen the repair ifstrengthen the repair if
desired.desired.

Replace the denture on the cast, and paint autopolymerizing resin in each grooveReplace the denture on the cast, and paint autopolymerizing resin in each groove
and dovetail, and build up excess.and dovetail, and build up excess.
Secure the denture to the cast with plaster or rubber bands,Secure the denture to the cast with plaster or rubber bands,
and cure in a pressure container of warm water for 30min. at 20 psiand cure in a pressure container of warm water for 30min. at 20 psi

Finish and polish denturesFinish and polish dentures

► Fractured Denture with Section(s) Missing:-Fractured Denture with Section(s) Missing:-
-- Make an impression with the denture in place to make a cast,Make an impression with the denture in place to make a cast,
particularly when a flange is broken, and the broken flange sectionparticularly when a flange is broken, and the broken flange section
has been lost.has been lost.
- If denture is broken into several sections, the denture may require a- If denture is broken into several sections, the denture may require a
repair, prior to making the impression of the lost flange.repair, prior to making the impression of the lost flange.
- Autopolymerizing resin is painted onto the cast to replace the missing- Autopolymerizing resin is painted onto the cast to replace the missing
portion.portion.

Shyn-yuan Lee, and Steven M. Morgano(1995)
Described a method of repairing a fractured complete denture
and simultaneously augment the deficient borders and to
correct an inadequate posterior palatal seal, correction were
made with modelling compound and an elastomeric
impression material.

METHODS TO STRENGTHEN THEMETHODS TO STRENGTHEN THE
REPAIRED PORTIONREPAIRED PORTION
-- Cobalt Chromium Alloy is a material of choice for strengtheningCobalt Chromium Alloy is a material of choice for strengthening
denture base.denture base.
- It provides a strong and well-fitting denture base but has certain- It provides a strong and well-fitting denture base but has certain
disadvantages:-disadvantages:-
1) Weight – tends to be heavier than those with acrylic base.1) Weight – tends to be heavier than those with acrylic base.
2) Lack of Adjustability – is far less adjustable than acrylic resin.2) Lack of Adjustability – is far less adjustable than acrylic resin.
- The problem of lack of adjustability and of increased weight can both- The problem of lack of adjustability and of increased weight can both
be minimised by restricting the cobalt-chromium component to abe minimised by restricting the cobalt-chromium component to a
horseshoe-shaped palatal strengthener set into the acrylic base.horseshoe-shaped palatal strengthener set into the acrylic base.
- This design results in an impression surface of acrylic resin and thus- This design results in an impression surface of acrylic resin and thus
preserves the advantage of adjustability.preserves the advantage of adjustability.

Berry H.H. & Funk O.J. (1971)-Berry H.H. & Funk O.J. (1971)-
used vitallium strengthener to prevent lowerused vitallium strengthener to prevent lower
denture breakagedenture breakage..
- Design –
 Had 4 tissue stops touching the crest of theHad 4 tissue stops touching the crest of the
mandibular ridge.mandibular ridge.
 The tissue stops are 2mm wide andThe tissue stops are 2mm wide and
located in the second molar and cuspidlocated in the second molar and cuspid
areas.areas.
 The connecting bar measures 4mm wideThe connecting bar measures 4mm wide
and 1mm thick and is raisedand 1mm thick and is raised
approximately 1-2mm above the crest ofapproximately 1-2mm above the crest of
the lower ridge. Retention webbingthe lower ridge. Retention webbing
measures 15mm from the lingual side ofmeasures 15mm from the lingual side of
the ridge.the ridge.
- Strengthener is incorporated in acrylic resin- Strengthener is incorporated in acrylic resin
and stabilized before packing.and stabilized before packing.

► Badr S.E., Stone C.R. & Unger J.W.(1989)Badr S.E., Stone C.R. & Unger J.W.(1989) –– developed a techniquedeveloped a technique
of “a metal insert to replace a fractured segment of a mandibularof “a metal insert to replace a fractured segment of a mandibular
complete denture.”complete denture.”
- In some patients where surgical reduction is not possible with little- In some patients where surgical reduction is not possible with little
space between the retro-molar pad & maxillary tuberosities, denturesspace between the retro-molar pad & maxillary tuberosities, dentures
are most often made quite thin and as such are prone to fracture.are most often made quite thin and as such are prone to fracture.
Procedure:-Procedure:-
1) Reline impression with polysulphide elastomeric impression material1) Reline impression with polysulphide elastomeric impression material
is made in the denture and cast is poured.is made in the denture and cast is poured.
2) Jaw relations are recorded and facebow-tansfer done to mount the2) Jaw relations are recorded and facebow-tansfer done to mount the
maxillary cast on the articulator.maxillary cast on the articulator.
3) Mount mandibular cast by using the jaw relation record.3) Mount mandibular cast by using the jaw relation record.

4) Remove the fractured portion of the mandibular denture and make a4) Remove the fractured portion of the mandibular denture and make a
pattern in Dura-Lay resin on the cast. Avoid contact with the opposingpattern in Dura-Lay resin on the cast. Avoid contact with the opposing
denture.denture.
5) Cut openings in the pattern to retain casting in the denture. Invest the5) Cut openings in the pattern to retain casting in the denture. Invest the
acrylic resin pattern and cast it in metal of choice.acrylic resin pattern and cast it in metal of choice.
6) After polishing the casting,6) After polishing the casting,
incorporate into the finalincorporate into the final
wax contour of denturewax contour of denture
base, invest and process.base, invest and process.

A study was done in our college Under The Able Guidance ofA study was done in our college Under The Able Guidance of
Dr N.P.PATIL(2006) to see theDr N.P.PATIL(2006) to see the “EFFECT OF JOINT
SURFACE CONTOURS ON THE TRANSVERSE
STRENGTH AND IMPACT RESISTANCE Of DENTURE
BASE RESIN REPAIRED BY VARIOUS METHODS”
► Repair was carried out by heat polymerization, autopolymerising resin
using pressure pot and autopolymerising resin with glass fibers (with
and without treatment with silane coupling agent). Samples were
given different joint surface contour namely butt and 450
bevel.
► Transverse and impact strength tests were tested using Instron
universal testing machine and Izod impact tester. .
► Glass fiber treatment with silane coupling agent significantly
increased the transverse and impact strength of autopolymerising
resin.

► For the Impact strength the effect of joint surface contour of butt and
450
bevel is not significant for the groups repaired by heat cure and
self cure, while it was significant for the groups reinforced by glass
fiber (with and without treatment with silane coupling agent), with 450
bevel joint showing higher strength.
It was concluded that:
► ¨ Self cure resin produced the lowest strength after repair.
► ¨ Fractured specimen repaired by heat cure method showed 30-40%
higher values of transverse strength as compared to cold cure Groups.
► The transverse and impact strength values after repair were highest
with autopolymerising resin with glass fibers after treatment with
silane coupling agent, having 450
bevel joint.
► Impact strength was not affected in case of samples repaired by self
cure and heat cure, but the strength increased in fiber reinforced
Groups with and without silane coupling agent treatment.

PREVENTION OF DENTURE FRACTUREPREVENTION OF DENTURE FRACTURE
1) A good processing technique which reduces or eliminates residual1) A good processing technique which reduces or eliminates residual
stresses within the denture and avoids surface defects.stresses within the denture and avoids surface defects.
2) Using higher strength polymers, impact resistant materials to reduce2) Using higher strength polymers, impact resistant materials to reduce
the tendency of fracture.the tendency of fracture.
3) Constructing dentures with metal plates for patients with heavy3) Constructing dentures with metal plates for patients with heavy
occlusions.occlusions.
- Greater Strength- Greater Strength
- Better Thermal Stimulation.- Better Thermal Stimulation.
4) The use of occlusal checks and inserts, help to reduce tooth wear.4) The use of occlusal checks and inserts, help to reduce tooth wear.
5) Avoiding deep incisal spaces and increasing the bulk of base5) Avoiding deep incisal spaces and increasing the bulk of base
thickness in areas palatal to incisors reduces the possibility of midlinethickness in areas palatal to incisors reduces the possibility of midline
fracture.fracture.
6) Placing a thin beading around a heavy labial frenum to improve the6) Placing a thin beading around a heavy labial frenum to improve the
seal has strengthening effect and leads to improved stress distribution.seal has strengthening effect and leads to improved stress distribution.

SummarySummary
► Resurfacing and replacement of the denture base of a completeResurfacing and replacement of the denture base of a complete
denture is complicated procedure requiring astute clinical judgmentdenture is complicated procedure requiring astute clinical judgment
and skill if the therapy is to be successful.and skill if the therapy is to be successful.
► When the denture bases are under-extended, when there has been aWhen the denture bases are under-extended, when there has been a
gross loss in the occlusal vertical dimension , and when centricgross loss in the occlusal vertical dimension , and when centric
relation and centric occlusion do not coincide, then fabrication of newrelation and centric occlusion do not coincide, then fabrication of new
denture would be treatment of choice.denture would be treatment of choice.
► A relined complete denture should be remounted on the articulatorA relined complete denture should be remounted on the articulator
and the occlusion refined to eliminate occlusal interferences resultingand the occlusion refined to eliminate occlusal interferences resulting
from three-dimensional denture displacement during relining.from three-dimensional denture displacement during relining.
► Relined or rebased dentures should be given the same care as newRelined or rebased dentures should be given the same care as new
dentures, and the patient should be recalled as often as necessary fordentures, and the patient should be recalled as often as necessary for
examination of the tissues and the jaw relationsexamination of the tissues and the jaw relations..

► Many factors can contribute to the fracture of a complete denture.Many factors can contribute to the fracture of a complete denture.
Recognition of these factors and their prevention or correction willRecognition of these factors and their prevention or correction will
result in dentures that are physiologically and functionally acceptableresult in dentures that are physiologically and functionally acceptable
for the patients.for the patients.
► Several methods for repairing dentures with autopolymerizing resinSeveral methods for repairing dentures with autopolymerizing resin
are described.are described.
► Successful denture repairs should provide adequate strength and theSuccessful denture repairs should provide adequate strength and the
minimal distortion to denture.minimal distortion to denture.
Tooth replacement Fractured dentures
Anterior teeth Posterior teeth
Non-separated parts
Separated parts
Missing parts
Denture repairDenture repair

ReferencesReferences
Resins in dentistry: DCNA 1975; vol. 19(2): 357-366.Resins in dentistry: DCNA 1975; vol. 19(2): 357-366.
Bolouri, Bell J.D. : The use of intraoral cores to repair complete and removableBolouri, Bell J.D. : The use of intraoral cores to repair complete and removable
partial processes. J.P.D. 1976; 36: 472-475.partial processes. J.P.D. 1976; 36: 472-475.
Beyli M.S. : Repair of fractured acrylic resin. J.P.D. 1980; 44: 497-503.Beyli M.S. : Repair of fractured acrylic resin. J.P.D. 1980; 44: 497-503.
Halperin A.R., Abadi B.J. : Repair of broken denture in resin undercuts. JPD, 1980;Halperin A.R., Abadi B.J. : Repair of broken denture in resin undercuts. JPD, 1980;
44: 224-228.44: 224-228.
Linear dimensional change of heat-cured acrylic resin complete dentures afterLinear dimensional change of heat-cured acrylic resin complete dentures after
reline and rebasereline and rebase Edmond H. N. Pow, T. W. Chow, and Robert K. F. ClarkEdmond H. N. Pow, T. W. Chow, and Robert K. F. Clark (J(J
Prosthet Dent 1998;80:238-45.)Prosthet Dent 1998;80:238-45.)
Beyli M.S. : An analysis of causes of fracture of acrylic resin dentures. JPD, 1981;Beyli M.S. : An analysis of causes of fracture of acrylic resin dentures. JPD, 1981;
46: 238-241.46: 238-241.
David E.H. : Immediate stabilization of a broken maxillary denture. J.P.D. 1983; 50:David E.H. : Immediate stabilization of a broken maxillary denture. J.P.D. 1983; 50:
289-292.289-292.
Farmer J.B. : Maxillary denture fracture. JPD 1983; 50: 172-175.Farmer J.B. : Maxillary denture fracture. JPD 1983; 50: 172-175.
Schneider R.L.: Diagnosing functional complete denture fractures. JPD 1985; 54:Schneider R.L.: Diagnosing functional complete denture fractures. JPD 1985; 54:
809-813.809-813.
Rudd K.D., Morrow M.R. : Dental laboratory procedures, complete dentures. 1stRudd K.D., Morrow M.R. : Dental laboratory procedures, complete dentures. 1st
edition 1986.edition 1986.
Stipho H.D. Effectiveness and durability of repaired acrylic resin joints. JPD 1987;Stipho H.D. Effectiveness and durability of repaired acrylic resin joints. JPD 1987;
58: 249-252.58: 249-252.
Wilson H.J. : Dental technology and materials for students. 8th Edn, 1987.Wilson H.J. : Dental technology and materials for students. 8th Edn, 1987.www.indiandentalacademy.com

Sherif E.B., Carl R.S.: A metal insert to replace a fracture segment of aSherif E.B., Carl R.S.: A metal insert to replace a fracture segment of a
mandibular C.D. JPD, 1989; 61: 250-251.mandibular C.D. JPD, 1989; 61: 250-251.
Andreopelons A.G., Polyzois G.L. : Repair with visible light cured denture baseAndreopelons A.G., Polyzois G.L. : Repair with visible light cured denture base
materials. Quint Int. 1991; 22: 703-706.materials. Quint Int. 1991; 22: 703-706.
Valitto P.K. : Wetting the repair surface of methylmethacrylate affects theValitto P.K. : Wetting the repair surface of methylmethacrylate affects the
transverse strength of heat polymerized repaired resin. JPD 1994; 72: 639-643.transverse strength of heat polymerized repaired resin. JPD 1994; 72: 639-643.
Darbar U.R., Huggett R. : Denture fracture: A survey. BDJ 1994; 176; 342-345.Darbar U.R., Huggett R. : Denture fracture: A survey. BDJ 1994; 176; 342-345.
Shyh-yuan Lee, Steven M.M. : Repair of posterior base of a maxillary CD by useShyh-yuan Lee, Steven M.M. : Repair of posterior base of a maxillary CD by use
of a cast of stone and resilient material. JPD, 1995; 74: 546-548.of a cast of stone and resilient material. JPD, 1995; 74: 546-548.
Phillips Science of Dental Materials. 10th edn, 1999.Phillips Science of Dental Materials. 10th edn, 1999.
Winkler S. : Essentials of complete denture prosthodontics. 2nd edn, 2000.Winkler S. : Essentials of complete denture prosthodontics. 2nd edn, 2000.
Swenson’s Complete denture: 5th edition.Swenson’s Complete denture: 5th edition.
KAWANO F. : The influence of soft lining materials on pressure distribution. JKAWANO F. : The influence of soft lining materials on pressure distribution. J
Prosth Dent. 1991; 65: 567-575.Prosth Dent. 1991; 65: 567-575.
DOOTZ E.E. ET AL : Physical property comparison of 11 soft denture linerDOOTZ E.E. ET AL : Physical property comparison of 11 soft denture liner
materials as a function of accelerated aging J Prosth Dent. 1993;.69: 114-119.materials as a function of accelerated aging J Prosth Dent. 1993;.69: 114-119.
LAMMIE AND STORER: A preliminary report on . denture or resilient plastics.LAMMIE AND STORER: A preliminary report on . denture or resilient plastics.
J Prosth Dent. 1958; 8: 411.J Prosth Dent. 1958; 8: 411.
BATES, J,F, AND SMITH, D.C.: Evaluation of indirect liners for dentures,BATES, J,F, AND SMITH, D.C.: Evaluation of indirect liners for dentures,
laboratory and clinical test. J. Am Dent Assoc.laboratory and clinical test. J. Am Dent Assoc.
GONZALEZ J.B. AND LANEY W.R. : Resilient material for denture prosthesis.GONZALEZ J.B. AND LANEY W.R. : Resilient material for denture prosthesis.
J Prosth Dent. 1966 16: 438444.J Prosth Dent. 1966 16: 438444.
Beyli M.S. : Repair of fractured acrylic resin. J.P.D. 1980; 44: 497-503.Beyli M.S. : Repair of fractured acrylic resin. J.P.D. 1980; 44: 497-503.www.indiandentalacademy.com

Relining rebasing and repair of complete denture/ dental courses

Empfohlen

Empfohlen

Weitere ähnliche Inhalte

Was ist angesagt?

Was ist angesagt? (20)

Ähnlich wie Relining rebasing and repair of complete denture/ dental courses

Ähnlich wie Relining rebasing and repair of complete denture/ dental courses (20)

Mehr von Indian dental academy

Mehr von Indian dental academy (20)

Kürzlich hochgeladen

Kürzlich hochgeladen (20)

Relining rebasing and repair of complete denture/ dental courses