PREPARATION OF MOUTH FOR REMOVABLE PARTIAL DENTURES Dr. Mazen kanout Mouth preparation includes procedures in four categories: 1. Oral Surgical Preparation. 2. Conditioning of Abused and Irritated Tissue. 3. Periodontal Preparation. 4. Preparation of abutment teeth. Oral surgical and periodontal procedures should precede abutment tooth preparation and should be completed far enough in advance to allow the necessary healing period. If at all possible, at least 6 weeks, but preferably 3 to 6 months, should be provided between surgical and restorative dentistry procedures. This depends on the extent of the surgery. Oral Surgical Preparation The longer the interval between the surgery and the impression procedure, the more complete the healing and consequently the more stable the denture-bearing areas.
The important consideration is that the patient not be deprived of any treatment that would enhance the success of the removable partial denture. 1- Extractions: Planned extractions should occur early in the treatment regimen but not before completion of a careful and thorough evaluation of each remaining tooth in the dental arch. Almost any tooth may be salvaged if its retention is sufficiently important to warrant the procedures necessary. 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 pathological findings. Residual roots adjacent to abutment teeth may contribute to the progression of periodontal pockets and compromise the results from subsequent periodontal therapy. The removal of root tips can be accomplished from the facial or palatal surfaces without resulting in a reduction of alveolar ridge height or endangering adjacent teeth. 3- Impacted Teeth All impacted teeth, including those in edentulous areas and those adjacent to abutment teeth, should be considered for removal.
Asymptomatic impacted teeth in the elderly that are covered with bone, with no evidence of a pathological condition, should be left to preserve the arch morphology. If an impacted tooth is left, it should be recorded in the patient's record and the patient should be informed of its presence. Roentgenogram should be taken at reasonable intervals. Any impacted teeth that can be reached with a periodontal probe must be removed to treat the periodontal pocket and prevent more extensive damage. 4-Malposed Teeth The loss of individual teeth or groups of teeth may lead to extrusion, drifting, or combinations of malpositioning of the remaining teeth. In most instances the alveolar bone supporting extruded teeth will be carried occlusally as the teeth continue to erupt. Orthodontics may be useful in correcting many occlusal discrepancies, but for some patients, such treatment may not be practical because of a lack of teeth for anchoring orthodontic appliances or for other reasons. In such situations individual teeth or groups of teeth and their supporting alveolar bone can be surgically repositioned. 5-Cysts and Odontogenic Tumors When a suspicious area appears on the survey film, a periapical roentgenogram should be taken to confirm or deny the presence of a lesion.
6-Exostoses and Tori Although modification of denture design can at times accommodate for exostoses, more frequently this results in additional stress to the supporting elements and compromised function. Ordinarily the mucosa covering bony protuberances is extremely thin and friable. Removable partial denture components in proximity to this type of tissue may cause irritation and chronic ulceration. Also, exostoses approximating gingival margins may complicate the maintenance of periodontal health and lead to the eventual loss of strategic abutment teeth. 7-Hyperplastic Tissue Hyperplastic tissue is seen in the form of: 1. Fibrous tuberosities. 2. Soft flabby ridges. 3. Folds of redundant tissue in the vestibule or floor of the mouth. 4. Palatal papillomatosis. All these forms of excess tissue should be removed to provide a firm base for the denture. This removal will produce a more stable denture, reduce stress and strain on the supporting teeth and tissue.
8-Muscle Attachments and Frena Muscle Attachments and Frena As a result of the loss of bone height, muscle attachments may insert on or near the residual ridge crest. The mylohyoid, buccinator, mentalis, and genioglossus muscles. In addition to the problem of the attachments of the muscles themselves, the mentalis and genioglossus muscles occasionally produce bony protuberances at their attachments, which may also interfere with removable partial denture design. The maxillary labial and mandibular lingual frena are the most common sources of frenum interference with denture design. These can be modified easily with any of several surgical procedures. Under no circumstances should a frenum be allowed to compromise the design or comfort of a removable partial denture. 9-Bony Spines and Knife-Edge Ridges Sharp bony spicules should be removed and knifelike crests gently rounded. These procedures should be carried out with minimum bone loss. 10- Polyps, Papillomas, and Traumatic Hemangiomas All abnormal soft tissue lesions should be excised and submitted for pathological examination before the fabrication of a removable partial denture. If the lesions not treated new or additional stimulation to the area introduced by the prosthesis may produce discomfort or even malignant changes in the tumor. 11- Hyperkeratoses, Erythroplasia, and Ulcerations All abnormal, white, red, or ulcerative lesions should be investigated regardless of their relationship to the proposed denture base or framework. The lesions should be removed and healing accomplished before fabrication of the removable partial denture.
12- Dentofacial Deformity Several dental professionals (prosthodontist, oral surgeon, periodontist, orthodontist, and general dentist) may play a role in the patient's treatment. 13-Osseointegrated Devices ) Implants ( This titanium implant was designed to provide a direct titanium-to-bone interface (osseointegrated). Implants are carefully placed using controlled surgical procedures, and in general bone healing to the device is allowed to occur before fabrication of a dental prosthesis.
14- Augmentation of Alveolar Bone Considerable attention has been devoted to ridge augmentation with the use of autogenous and alloplastic materials, especially in preparation for implant placement. Larger ridge volume gains necessitate consideration of autogenous grafts; however, these procedures are accompanied with concerns for surgical morbidity. Considerable emphasis must be placed on sound clinical understanding that some of the alloplastic materials can migrate or be displaced under occlusal loads if not appropriately supported by underlying bone and contained by buttressing soft tissue. CONDITIONING OF ABUSED AND IRRITATED TISSUE Patients who require conditioning treatment often demonstrate the following symptoms: 1- Inflammation and irritation of the mucosa covering the denturebearing areas 2- Distortion of normal anatomic structures, such as incisive papillae, the rugae, and the retromolar pads. 3- A burning sensation in residual ridge areas, the tongue, and the cheeks and lips. These conditions are usually associated with illfitting or poorly occluding removable partial dentures. However, nutritional deficiencies, endocrine imbalances, severe health problems (diabetes or blood dyscrasias), and bruxism must be considered in a differential diagnosis.
If a new removable partial denture or the relining of a present denture is attempted without first correcting these conditions, the chances for successful treatment will be compromised because the same old problems will be perpetuated. The patient must be made to realize that fabrication of a new prosthesis should be delayed until the oral tissue can be returned to a healthy state. The first treatment procedure should be an immediate institution of a good home care program. A suggested home care program includes: 1. Rinsing the mouth three times a day with a prescribed saline solution. 2. Massaging the residual ridge areas, palate, and tongue with a soft toothbrush. 3. Removing the prosthesis at night. 4. Using a prescribed therapeutic multiple vitamin. Use of Tissue Conditioning Materials The tissue conditioning materials are elastopolymers that continue to flow for an extended period, permitting distorted tissue to rebound and assume its normal form. These soft materials apparently have a massaging effect on irritated mucosa, and because they are soft, occlusal forces are probably more evenly distributed. Maximum benefit from using tissue conditioning materials may be obtained by: 1-eliminating deflective or interfering occlusal contacts of old dentures (by remounting in an articulator if necessary). 2-extending denture bases to proper form to enhance support, retention, and stability.
3- Relieving the tissue side of denture bases sufficiently (2 mm) to provide space for even thickness and distribution of conditioning material. 4- Applying the material in amounts sufficient to provide support and a cushioning effect. 5- Following the manufacturer's directions for manipulation and placement of the conditioning material. The conditioning procedure should be repeated until the supporting tissues display an undistorted and healthy appearance. Many dentists find that intervals of 4 to 7 days between changes of the conditioning material are clinically acceptable. An improvement in irritated and distorted tissue is usually noted within a few visits. If positive results are not seen within 3 to 4 weeks, one should suspect more serious health problems and request a consultation from a physician.