semenar mouth preperation

Mouth preperation

Mouth preparations are clinical procedures that accomplished to prepare the mouth for reception of the prosthesis. It’s fundamental for successful removable partial denture prosthesis since any restoration to be successful five important factors must be considered:

1. Restore normal teeth functions

2. Aesthetic

3. Comfortable

4. Long standing

5. Cost

When a removable partial denture is preferred choice of treatment, mouth preparation came after an orderly, sequential plan of actions which include:

• Patient’s medical & dental history

• Digital & visual examination


• Radiographs of teeth & edentulous spaces

• Surveyed & occluded study casts

Methods of Correcting Undesirable Occlusal Plane

Enameloplasty

Usually the procedure is confined to the enamel except in older patients where sufficient secondary dentin is present.

• In cases with buccally tilted and extruded maxillary molars, the palatal cusps will lie below the occlusal plane. In these cases reduction of palatal cusps alone will provide relief from occlusal interference.

Correction of malalignment

Teeth that are malposed facially or lingually are frequently more difficult to correct than overerupted or submerged teeth.

Malaligned teeth compromise the contours & positions of removable partial denture components, while minor malalignment corrections can be tried by altering design of partial denture.

Sequence of abutment preparation on sound enamel or existing restorations

.  After alterations of axial contours and before rest seat preparations are instituted, an impression of the arch should be made in irreversible hydrocolloid and cast formed, that is surveyed to determine the adequacy of axial alterations before proceeding with rest seat preparations. If axial surfaces require additional recontouring, it can be done at the same appointment.


 Mouth preparation should follow removable partial denture design outlined on the diagnostic cast. Proposed changes to the abutment teeth should be made on the diagnostic cast and outlined to indicate the area, amount & angulation of modification to be done.

Abutment preparation using crowns:

When multiple crowns are to be restored as abutments, it is best that all wax patterns be made at the same time. This can be accomplished with either removable dies or solid cast with individual dies to refine the margins.

After cast is placed on the surveyor to conform to the selected path of placement & after wax patterns have been preliminary carved for occlusion and contact, the proximal surfaces that are to act as guiding planes are carved parallel to the path of placement with a surveyor blade.

Guiding planes are extended from marginal ridge to the junction of the middle and gingival 3rd of the involved tooth surface. Guiding plane should not be extended to the gingival margin, as the minor connector must be relieved when it crosses the gingiva.

After the guiding planes are parallel & any other contouring is accomplished to accommodate the removable partial denture design, occlusal rest seats are carved in the wax pattern.

One of the advantages of making cast restorations for abutment teeth is that mouth preparations that would otherwise have to be done in the mouth may be done on the surveyor with far greater accuracy.

Preparation of abutment teeth includes:

1. Preparing guiding planes

2. Modifying survey lines

3. Preparation of composite retentive areas.


4. Preparing rest seats

Preparing guiding planes

Guiding planes are naturally occurring or prepared parallel areas on vertical tooth surfaces that are contacted by certain rigid parts of the RPD framework during the placement & removal of the prosthesis.

Guiding planes should be prepared on sound enamel or on appropriately restored tooth surfaces.

Length

 Guiding planes should be longer (occlusogingivally) for tooth supported than for distal extension prostheses .

 Proximal guiding planes for all tooth-supported prostheses should be approximately one half –two thirds the length of the occlusogingival dimension of the coronal enamel. The guiding plane should extend from the marginal ridge cervically.

 Guiding planes on teeth that serve, as abutments for distal extension prostheses should be one- third to one half the occlusocervical dimension of the coronal dimension of the coronal enamel.

Width

From an occlusal view, guiding planes on proximal tooth surfaces may be slightly curved buccolingually to more or less follow the natural tooth contour. Buccolingually, guiding planes on proximal tooth surfaces should be about two-thirds as wide as the distance between thebuccal & lingual cusp tipsMouth preparations include many various procedures which vary from patient to patient between minimal mouth preparations to extensive treatment may including surgical interference...

These procedures:

1. Relief of pain and infection

2. Oral surgical procedures

3. Conditioning of abused and irritated tissue

4. Periodontal therapy

5. Correction of occlusal plane

6. Correction of malalignment

7. Abutment teeth preparation

.