Preparation of mouth for RPD

Preparation of mouth for RPD is a fundamental to successful RPD service it is an important procedure since it prescribe that the prosthesis must not only replace what is missing but must also preserve the remaining tissue and structure that will enhance the partial denture .
The steps for RPD construction :
1. Diagnosis and treatment plane
2. Preparation of mouth for RPD
3. Impression procedure for RPD
4. Occlusal relationship for RPD
5. Trial stage
6. Initial placement ,adjustment ,and servicing of RPD
Mouth preparation includes procedures in three categories :
1. Oral surgical preparation.
2. Periodontal preparation of abutment teeth.
3. Preparation of abutment teeth .
The objective of the procedures :
a) To return the mouth to optimum health.
b) To eliminate any condition that would be detrimental to the success the RPD.
Oral surgical preparation :
The longer the time between surgery and impression procedure the more complete the healing and consequently the more stable the denture bearing area .A variety of oral surgical technique can prove beneficial to the clinician in preparing the patient for pre prosthetic replacements .
The most common oral condition or changes in which surgical intervention indicated:
1) Extraction:
Planed extractions should occur early in the treatment regimen ,but not before careful and through evaluation of each remaining tooth in the dental arch completed .Each tooth must be evaluated concerning its strategic importance and its potential contribution to the success of the RPD .The extraction of non strategic teeth that would present complications or those whose presence may be detrimental to the design of the partial denture is a necessary part of the overall treatment plan.
2) Removal of Residual roots:
Generally ,all retained roots or root fragments should be removed this is particularly true if they are in close proximity to the tissue surface or if there is evidence of associated pathology . Residual roots adjacent to abutment teeth may contribute to the progression of periodontal pockets and compromise the result from sub sequent periodontal therapy.
3) Impacted teeth:
All impacted teeth should be considered for removal ,this applies equally to the impaction in edentulous area ,as well as to those adjacent to abutment teeth .
4) Malposed teeth:
The loss of individual teeth or group of teeth may lead to extrusion, mesial drifting , or combinations of malpositioning of remaining teeth . In most instances the alveolar bone supporting extruded teeth will be carried occlusally as the tooth continues to erupt. Orthodontics may be useful in correction many occlusal discrepancies ,but for some patients such treatment may not be practical because of lack of teeth for anchorage of the orthodontics appliance or for other reasons .In such a situation individual teeth or groups of teeth and their supporting alveolar bone can be surgically repositioned ,this type of surgery can be accomplished in an outpatient setting and should be given serious consideration .
5) Cyst and odontogenic tumor:
The diagnosis may appear obvious from clinical and radiographic examinations the dentist should confirm that diagnosis through appropriate consultation &if necessary biopsy the area &submit the biopsy to pathologist.
6) Exostosis &tori:
Ordinarily mucosa covering bony protuberance (Exostosis &tori) is extremely thin &friable. Patient denture component in proximity to this type of tissue may cause irritation &chronic ulceration. Although modification of denture design can, at time, accommodate for exostosis more frequently, this result in additional stress to the supporting element &compromised function. Surgical removal of tori bony exostosis can be done.
7) Hyperplasic tissue:
Hyperplasic tissue are seen in the form of fibrous tuberosity, soft tissue, fold of redundant tissue in the vestibule or floor of the mouth &palatal papilomatosis. All these form of excess tissue should be removed surgically. Always some form of surgical stent considered for these patient so that the period of healing will be more comfortable.
8) Muscle attachment &freni:
As a result of the loss of alveolar bone height, muscle attachment may insert in/or near the alveolar crest. The mylohyiod, buccinators, mentalis & genioglossus muscle are those most likely to introduce problem of this nature beside that the attachments of the muscles themselves ,the mentalis& genioglossus muscles occasionally produce bony protuberance at their attachment that may also interfere with RPD design. The comfort &function of the RPD can enhance through repositioning of attachment specially mylohyiod muscle, however repositioning of genioglossus muscle is more difficult to reposition .
9) Bony spine and knife edge ridge:
Sharp bony spicules should be removed and knife like crest gently rounded. These procedures should be carry out with minimum bone loss, if, the correction of a knife edge alveolar crest result in insufficient ridge support for the denture base, the dentist should restore the vestibular deepening for correction of the deficiency or insertion of the various bone grafting materials that have demonstrated successful clinical trials.
10) Polyps, Papillomas, and Traumatic Hemangiomas:
All abnormal soft tissue lesions should be excised and submitted for pathologic examination before the fabrication of RPD.
11) Hyperkeratosis, erythroplasia and ulceration:
All abnormal white ,red, or ulcerated lesion should be investigated regardless of their relationships to proposed denture base framework.
12) Dentofacial deformity :
A patient with dentofacial deformity may have multiple missing teeth . Correction of the jaw deformity can simplify the dental rehabilitation. Surgical correction can be made in horizontal , sagital or facial planes . Mandible & maxilla may be positioned anteriorly or posteriorly , & their relationship to the facial planes may be surgically altered to achieve improved appearance . Replacement of missing teeth & development of a harmonious occlusion are very difficult in treating those patient .
13) Osseo integrated devices:
A number of implant device for replacement of teeth have been introduce titanium implant was designed to provide a direct titanium –to bone interface (osseo integrated) the implant are placed using clean &controlled oral surgical procedure and are allowed to heal before surgical exposure and fabrication of a dental prosthesis .
14) Augmentation of alveolar bone
Hydroxyl appetite has been used as a material for augmentation of deficient alveolar bone ,this material display a lack of toxicity and demonstrates no inflammatory or foreign body responses .This material provide increase in ridge width and height and also provide a matrix for new bone formation .
Conditioning of abused and irritated tissues
Many partial denture patients may require conditioning of the supporting tissue in the edentulous area before the final impression. The abuse tissues caused by ill-fitted denture, nutrition disturbances, diabetes, and blood dyscrasia.
Those who need conditioning treatment are those who have the following symptoms :
1. Inflamed and irritation tissue of the mucosa covering the denture bearing area.
2. Distortion of the normal anatomic structures ,such as incisive papillae the rugae and retromolar pads.
3. A burning sensation in residual ridge area ,the tongue, the cheeks and the lips.
4. Nutritional deficiencies ,endocrine imbalances ,sever health problems and bruxism must be considered also .
The conditions which are associated with ill-fitting or poorly occluded RPD, should be treated before relining or making a new RPD. The treatment procedure includes good home care by:
1. Rinsing the mouth three times daily with prescribed saline solutions.
2. Massaging the residual ridge area, palate and tongue with a soft tooth brush.
3. Removing the prosthesis at night.
4. Using a prescribed therapeutic multiple vitamins along with a prescribed high protein low carbohydrate diet .