Tooth Whitening

Among the most annoying and difficult problems in prosthetic dentistry are those related to prolonging the useful life of dentures

As the denture foundations change, the impression surfaces of the dentures cease to fit the tissues properly
The loss of the foundations for dentures causes loss of their retention and stability

If the occlusal vertical dimension is enough and if the dentures didn’t lose their orientation to their basal seat, the dentures may be corrected in the short working time allowed by the available impression materials (more…)

The broken edges are cleaned of debris and other interferences so that the two parts will fit together well

The two halves are held together by means of an old bur, which is luted to the teeth and resin surfaces by means of sticky wax

No wax is placed over the fracture so that the tissue and palatal sides of the fracture can be examined to see that they are in correct apposition

Plaster is vibrated gently onto the palatal side to prevent air bubles and is then set on the balance of the mix to form cast (more…)

There are a number of causes of porosity

If the porosity occur on the surface of the denture:

-proper cleansing of the denture will be difficult

-the appearence of the denture will be unsightly
Even tough the porosity may be internal, the denture base will be weakened

Since each internal pore is an area of stress concentration, the denture may warp as the stress relaxInternal porosity may develop in the portion of a denture base as a result of the vaporisation of the monomer or of the (more…)

Never pound on the flask with a metal hammer
Sould be accomplish with considerable care

Shaping and Polishing The Cured Resin Bases

The dentures are removed from the artificial stone casts (more…)

Denture base material or acrylic polymers are supplied in several form:

-The powder-liquid type
-Either heat or chemically accelerated and gel types
Measure and mix the polymer and monomer according to the manufacturer’s directions

10 cc of monomer and 30 cc of polymer will be enough to back an average sized denture
Pour the monomer into a clean porcelain jar (more…)

The elimination of the wax from the dentures flasked to form a mould into which resin may be packed is called boil-out or wax elimination process
Setted flasking stone

Boiling water 4-5 min.

Soften wax

Separation of the flask: If all undercuts were properly blocked-out in the investing procedure, no breakage of the hellls will take place
Lift-out the base trays carefully (more…)

The process of investing the cast with the waxed denture in a flask to make a sectional mould used to form the acrylic resin denture base
Trial Dentures

                 waxed (more…)

Retentive quality
Esthetics values of the denture
The art portion of the polished surfaces should for esthetics reasons imitate the form of the healthy tissues around the natural teeth
A slight root projection to follow the individual tooth should be carried out
The form of the denture bases between the teeth and the denture border should be shaped in such a manner as to aid retention by the mechanical directional forces of the muscles and tissues (more…)

Three principal factors are conserned in the functional harmony of denture bases

Basal or impression surface
Occlusal surface of the teeth
The shape and the form of the polished surfaces of the dentures

The shape of the polished surfaces (more…)

A portion of wax is removed, the wax softened and the maxillary first premolar is placed in position
The facial surface of the maxillary first premolar is on the occlusal plane and the lingual cusp is raised off the plane approximately 0,5 mm
The lingual cusp is over the line on the occlusion rim which represents the crest of the mandibular ridge
The facial and lingual cusps of the maxillary second premolar touch the occlusal plane
The lingual cusp is over the crest of the ridge
Only the mesiolingual cusp of the maxillary first molar touches the occlusal plane and the lingual cusps are over the crest of the mandibular ridge
No cusp of the maxillary second molar touches the occlusal plane.
The facial cusps of the maxillary teeth form a gentle curve, while the lingual cusps form a similar curve aboutt 0,5 mm below the facial cusp
Mandibular first molar, mandibular second molar are set in centric occlusion
The placement of the mandibular posterior teeth determines how will the teeth occlude.
In centric occlusion, the facial cusps of the mandibular teeth contact the central fossae of the maxillary teeth while the lingual cusps of the maxillary teeth fit into he central fossae of the mandibular teeth. (more…)