• In this technique, an osteotomy is performed by splitting the
superior–inferior dimension of the residual jaw and the bone is
grafted within this osteotomy.
• In the maxilla, Le Fort osteotomy is performed with interpositional
grafting. The advantage of this technique is that it shows less
resorption in comparison to the onlay grafting procedure.
• After grafting, secondary soft tissue procedure to increase the
vestibular depth is usually necessary.
• Horizontal sandwich technique is used to augment the anterior
mandible. Advantage is that it shows less incidence of nerve
paraesthesia when compared to visor osteotomy.
• Allogenic bone graft can be used instead of autogenous graft.
• This is the procedure of choice for mandibular ridge augmentation,
as it includes a combination of osteotomy techniques (horizontal or
vertical). This procedure involves the movement of the pedicle of
the bone along with blood supply.
Inferior bone grafts ( fig. 3-4)
• This was first described by R.E. Marx and T.R. Saunders (1986) for
reconstruction of the mandible following resection.
• It was modified by P.D. Quinn, K. Kent, I.I. MacAfee and A.
• Mandible has 5–8 mm of bone and there are chances of pathological
• A supralaryngeal incision is made from the mastoid process to the
mastoid process on the other side.
• Subsequently, the inferior border of the mandible is dissected.
• A freeze-dried allogenic mandible is hollowed out and is used as a
tray to hold the autogenous cancellous graft harvested from the iliac
• If needed, hydroxyapatite or allogenic particulate bone is used as
• Graft is secured in place using sutures or wires.
• The freeze-dried allogenic bone crib is replaced by a process called
creeping substitution over a period of several months.
• Implants can be placed into the graft 4 months postsurgery.
• Advantages of this technique are consistent; 11–17 mm of bone
augmentation is achieved with a resorption rate of only 5%.
FIGURE 3-4 Inferior border bone grafting technique.
Vestibuloplasty is defined as ‘a surgical procedure designed to restore
alveolar ridge height by lowering muscles attachment to the buccal, labial and
lingual aspects of the jaws’. (GPT 8th Ed)
• When other conservative procedures fail
• A healthy patient who is highly motivated
• A geriatric patient who is debilitated or medically compromised
• When vertical ridge height is inadequate
• A severely prognathic patient
• A patient who cannot bear the cost and time of the treatment
• This was first described by R.B. McIntosh and H.L. Obwegeser
• It is indicated when maxillary denture is unstable due to shallow
vestibular depth or high muscle attachment, but there should be
sufficient healthy mucosa in the vestibule.
• Mouth mirror test is used to assess the amount of mucosa.
• Mouth mirror is used to reflect the soft tissue to the desired
vestibular depth; if abnormal shortening of the lip is not noticed,
then sufficient mucosa exists to do the procedure.
• A subperiosteal tunnel is created by dissecting any underlying
submucosal connective tissue away from the periosteum.
• The intervening submucosal tissues are then excised or repositioned
• An overextended surgical stent or overextended denture is placed to
• Stent is removed after complete healing.
• New denture is then fabricated to a new maxillary form and
Secondary epithelialization (fig. 3-5)
• This involves the use of apically repositioned flap sutured to the
periosteum to the desired sulcus depth.
• Exposed tissues are allowed to heal by granulation and secondary
• This can be used when hypermobile and hyperplastic ridges are
present and can be reduced while the ridge is extended.
• Overcorrection is advised beyond the desired sulcus depth, as
chances of relapse are very high.
FIGURE 3-5 Secondary epithelialization procedure: (A)
incision of the ridge; (B) supraperiosteal reflection; (C)
suturing of flap at new sulcus depth and placement of splint.
Epithelial graft vestibuloplasty
• It is a secondary epithelization procedure which uses skin or
mucous membrane graft to cover the exposed tissues.
• It was first described by J.F. Esser (1917) and later developed by
• It is used to enhance retention, stability and support of a denture in
highly resorbed maxilla or mandible.
• It is used when there is high muscle attachment that interferes with
the development of adequate border seal.
• Adequate vertical height of the bone is required to allow relocation
• This technique is the most preferred and predictable of all the
Lip switch procedures (transitional flap vestibuloplasty) (fig. 3-6)
• It was first described by V.H. Kazanjian (1935).
• Indicated for patients with insufficient vestibular depth owing to
mandibular atrophy and high muscle and soft tissue attachments.
• This technique effectively increases the vestibular depth in the
patients having bone height more than 15 mm.
• If the bone height is less than 15 mm, then the prosthetic results are
compromised and other procedures such as ridge augmentation are
• A submucosal dissection is made from the inner lower lip to the
• Then supraperiosteal dissection is done to remove the muscle and
connective tissue attachments inferiorly to the desired vestibular
• Periosteal flap is dissected from the bone and sutured to the raw lip
• Raised mucosal flap is adapted to the exposed bone to the depth of
the new vestibule and is fixed with sutures or stent.
• Possible complications: Pain, oedema and/or transient mental nerve
FIGURE 3-6 Lip switch technique of vestibuloplasty: (A)
incision made in labial mucosa or periosteal flap; (B) flap is
reflected to the depth of vestibule; (C) flap sutured.
Resilient liners (Fig. 3-7) are elastomeric polymers which are used to
prevent chronic soreness from complete dentures and to preserve the
FIGURE 3-7 Resilient liner. Source: (Reprinted by permission of GC
Types of resilient liners on the basis of their composition are as
(v) Ethyl methacrylate elastomers
Ideal requirements of resilient liners
• Material should have adequate hardness and strength and its
hardness should not change with time.
• Material should adhere well to the denture base.
• Material should recover well from deformation.
• Material should be easily cleaned and adjusted.
• Material should not be affected by the microorganisms and their
• Material should be colour stable, odourless, tasteless, nonirritating
• Material should be dimensionally stable and accurate.
• Material should not distort the denture base.
• Material should have good surface wettability.
• Vinyl and acrylic polymers are made resilient by adding oily or
• Hydrophilic polymer is a mixture of polyethylene glycol
• Once hardened, the material can be polished by conventional
• It becomes flexible when placed in water or in moist environment of
• Resilient liners are used in case of resorbed or atrophied edentulous
ridges which require protection (e.g. in knife-edged ridges, mental
foramen region, dehiscent mandibular canal or surgically excised soft or
bony tissues). Resilient liners provide excellent protection to
• These are used when surgical correction of bony undercuts is
contraindicated. Resilient liners are useful in patients who cannot
afford or undergo surgery for correction of the bilateral undercuts.
These materials owing to their flexibility facilitate insertion and
removal without compromising retention.
• These are used in the patients with parafunctional habit such as
bruxism. The constant grinding of the occlusal surfaces of the
denture teeth transmit intermittent shear stress to the basal seat
which results in mucosal irritation and subsequent bone resorption.
Resilient liners protect the supporting tissues from excessive stress.
• These are used in the relief area such as mid-palatal raphe or
anterior nasal spine. The soft flexible material provides relief to
• These are used when congenital or acquired oral defects are to be
restored. Resilient liners are valuable in fabricating prosthesis such
as obturator to restore congenital or acquired oral defects.
• It can be indicated in xerostomic patients. However, it should be
avoided in severe xerostomic patients, as they too can cause
• These are used in cases where the edentulous arch opposes the
• Resilient liners prevent the problems of chronic soreness from
complete dentures and thus help in preserving the supporting
• Plasticizer leaches out over the period of time making it hard and
• Silicone elastomers do not adhere well with the acrylic resin denture
base and thus are prone to get discoloured, difficult to finish and
polish, dimensionally unstable and affected by the metabolites of
• Polyurethanes are ultra-soft and comfortable but are difficult to
• Ethyl methacrylates can be processed by compression moulding
technique and can be easily finished and polished by conventional
Tissue conditioners (Fig. 3-8) are used to treat abused and
compromised tissues due to congenital or acquired abnormalities,
parafunctional habits, systemic deficiencies or faulty dentures. The
softness and flexibility of these materials help in protecting the
supporting tissues from functional and parafunctional occlusal
FIGURE 3-8 Tissue conditioners. Source: (Reprinted by permission of
• For temporary reline of dentures following oral surgery
• For conditioning the denture-bearing areas to healthy state
• As an aid in the treatment of chronic soreness from dentures
• As an impression material to reline complete dentures
• As a final impression material for new complete dentures
• For temporary relining of loose immediate dentures
• For temporary obturation and protection of surgical areas
• As a stabilizer for baseplates or surgical stents
Composition and characteristics
• Tissue conditioners are composed of polyethyl methacrylate and an
aromatic ester ethyl alcohol mixture.
• When these materials are mixed, they form a cohesive, resilient gel.
• The material does not adhere to the wet mucosa but readily adhere
to dry acrylic resin, to skin or to old tissue-conditioning material.
• Flow of the material can be improved by adding plasticizing liquid.
• These continue to flow under pressure for several days.
• To obtain good results, the material should be changed after every
• The material usually remains plastic but will become grainy and
discoloured, if in contact with denture for more than 2 weeks.
• Hyperaemic or traumatized oral mucosa because of ill-fitting
• Depressed area with suction cups
• General debilitating patients
• For patients who cannot do without dentures over an extended
period of time, tissue conditioners are used.
• Before the fabrication of new dentures, the hypertrophic, irritated,
hyperaemic and abused oral tissues should be conditioned to a
• Self-curing, slowly polymerizing material provides an excellent
medium to aid in conditioning of the abused tissues.
• After occlusal adjustments and correction of the underextended or
overextended borders, tissue conditioning material is applied.
• Tissue side of the denture and the borders are reduced by
• Posterior palatal seal and the buccal shelf region are not reduced, as
• Also, anterior stops are provided by reducing a small area of 3 × 3
mm in the cuspid region during initial relief.
• Anterior and posterior stops are necessary to correctly orient the
dentures to the ridges during placement of the material and to
maintain a correct vertical dimension.
• Material is mixed following the manufacturer’s instructions.
• Material is spread evenly on the tissue surface and border areas of
• Dentures are placed in the mouth and the patient is instructed to tap
the dentures lightly together.
• The dentures are left in the mouth for several minutes for setting.
• Any excess material is trimmed using a sharp BP blade.
• Pressure spots are relieved using acrylic trimmer or vulcanite bur.
• Dentures are placed back on the ridges, appearance is checked and
the vertical dimension is verified.
• The centric relation position should coincide with the centric
• The patient is recalled after 72 h and he/she is instructed not to
brush the tissue surface of the denture.
• The denture should be cleaned with lukewarm water.
• When the patient returns, the dentures and the tissues are examined
and necessary corrections are made.
• Once the tissues return to normal health, preliminary impressions
• Epulis fissuratum is caused due to overextension of the labial
• Generalized soreness of the denture-bearing area in a new denture
wearer is due to increased vertical dimension.
• Mandibular tori are most commonly located lingual to the premolar
• Maxillary tori are most commonly located in the mid-palatal region.
Impressions in complete dentures
Factors Responsible for Effective Support of the
Mucostatic Impression Technique, 56
Mucocompressive Impression Technique, 57
Selective Pressure Technique, 57
Biological Consideration in Maxillary Impressions, 57
Methods to Locate Anterior Vibrating Line, 61
Biological Considerations in Mandibular Impressions, 62
Ideal Requirement of Impression Trays, 67
Points to Consider during Tray Selection, 67
Requirements of a Primary Cast, 68
Ideal Requirements of a Custom Tray, 69
Materials Used for Fabrication, 69
Spacer Thickness and Design, 69
Multistep or Incremental or Sectional Border
Single Step or Simultaneous Border
Secondary Impression or Wash Impression, 72
Rubber Base Impression Material, 74
Impression making is one of the most important steps in the
construction of dentures. Primary objective of the impression
procedure is to accurately record the entire denture-bearing areas to
construct stable, precise fit and retentive dentures. The clinician
should be well versed with the anatomy of the edentulous arches and
according to the existing condition should be able to select an
appropriate impression technique.
An impression is defined as ‘the negative likeness or copy in reverse of the
surface of an object; an imprint of the teeth and adjacent structures for use in
‘An impression is the negative form of the teeth and/or other tissues of the
oral cavity, recorded at the moment of crystallization of the impression
Objectives of Impression Making
There are five primary objectives of impression making. These are as
(i) Preservation of remaining structures
Impression can be made in dentulous, partially dentulous or
completely edentulous patients and also in the patients with
congenital or acquired defects.
The famous dictum, proposed by Muller DeVan (1952), states that
‘...our task is not to try to maintain function, in scope, degree and
direction as it had been prior to the mutilation, but rather to preserve
what remains of the oral mechanism’.
It is widely accepted that with the loss of natural teeth the
remaining alveolar ridge resorbs. Although there is individual
variation on the rate of resorption, certain local factors may enhance
or slow its rate. Apart from the factors such as occlusion, interocclusal
distance and centric relation coinciding with the centric occlusion, the
type of impression technique plays an important role in the overall
health of the soft and hard tissues. For example, application of
pressure in the impression technique will reflect as pressure in the
denture base and will result in increased rate of resorption and soft
It is defined as ‘that quality inherent in the dental prosthesis acting to resist
the forces of dislodgement along the path of placement’. (GPT 8th Ed)
Retention can also be defined as the ability of the prosthesis to
withstand displacement against its path of opening.
Size of denture-bearing area: Retention increases with an increase of
denture-bearing area. More is the denture-bearing area, more is the
surface area available and, therefore, more is the retention. Size of the
maxillary denture-bearing area is 22.96 cm2
mandibular denture area is 12.25 cm2
; therefore, maxillary dentures
have more retention than the mandibular dentures.
Quality of denture-bearing area: Firm, keratinized tissues provide best
support and do not move easily and, therefore, provide maximum
retention in comparison to tissues that get easily displaced during
Quantity and quality of saliva: Quality of the saliva determines
retention. Thick and ropy saliva gets accumulated between the
tissue surfaces of the denture and the mucosa leading to loss of
retention. Likewise, thin and watery saliva also leads to reduced
Condition of mucosa and submucosa: Maximum coverage without undue
displacement of the tissues during impression making determines
retention in the complete denture.
Neuromuscular control: It refers to the functional forces exerted by the
musculature of the patient that can affect retention. This is primarily
a learned biological phenomenon. Individuals appear to differ in
their ability to develop the motor coordination and coordinated
reflexes necessary to manipulate dentures.
Ridge characteristics: An ideal ridge is parallel or nearly parallel with
adequate vertical height and flat crest. This type of ridge provides
maximum amount of support and stability and retention.
Ridge relationship: There should be an adequate inter-ridge distance
between the upper and the lower ridges. Excessive inter-ridge
distance results in poor stability and retention because of the
increased leverage. A small inter-ridge distance will lead to
difficulty in arranging the teeth and maintaining a proper freeway
Orofacial muscles provide supplementary retentive force, if the
• Teeth are arranged in neutral zone between the cheeks and the
• Polished surfaces of the dentures are properly shaped.
• Base of the tongue serves as an emergency retentive force (Fig. 4-1).
• Occlusal plane should be at the correct level.
• Denture bases should be extended over the maximum area possible.
• Muscle control and patient tolerance often play a vital role in
retention of the complete denture prosthesis. It is the muscle control
that enables the patient to function with dentures which rest on the
basal tissues that have undergone the resorptive changes.
FIGURE 4-1 Base of the tongue acts on emergency retentive
Undercuts: Mild undercuts help in providing retention. Also, unilateral
undercuts may aid in retention but severe bilateral undercuts will
mostly require surgical intervention before denture fabrication.
Retentive springs: Mode of retention which is not in use currently.
Magnets: Intramucosal magnets aid in improving the retention of
Denture adhesives: These are nontoxic soluble materials, which are
supplied as powder, cream or liquid and are applied to the tissue
side of the denture to improve denture retention and stability.
Suction chambers: These were used in practice in the past to aid in
retention of the maxillary denture. These act by creating negative
pressure and increasing retention. These have the potential to create
palatal hyperplasia and even palatal perforation in extreme cases.
Contour of denture base: The polished surface of the denture base
should be properly placed. Proper contour and design of the
polished surface should harmonize with the function of the tongue,
lips and cheeks to effect seating of the denture.
Parallel buccal and lingual walls: These provide significant retention by
increasing the surface area between the denture base and mucosa.
This enhances the retention by increasing the interfacial surface
tension and atmospheric forces.
Adhesion: It is defined as ‘the physical attraction of unlike molecules to
one another’. Adhesion of saliva to the mucous membrane and the
denture base is achieved through ionic forces between charged
salivary glycoproteins and surface epithelium or acrylic resin. A
thin film of saliva formed between the denture and the tissue
surface helps to hold the denture to the mucosa. Retention by
adhesion is proportional to the amount of denture-bearing area.
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