BDS8229 Clinical Partial Prosthodontics Mouth Preparation PDF

BDS8229 Clinical partial prosthodontics: Mouth Preparation WHAT IS MOUTH PREPARATION ? It is the adjustment or the preparation of the intraoral structures to receive the removable partial denture. Steps of RPD construction 1. Diagnosis and treatment plan 2. Survey, determine the path of insert...

BDS8229 Clinical partial prosthodontics: Mouth Preparation WHAT IS MOUTH PREPARATION ? It is the adjustment or the preparation of the intraoral structures to receive the removable partial denture. Steps of RPD construction 1. Diagnosis and treatment plan 2. Survey, determine the path of insertion, and tripod 3. Mouth preparation and impression for the RPD framework 4. try-in of metal framework 5. Maxillomandibular registration (obtain face bow, VDO, and CR records) 6. Tooth selection 7. Wax partial denture try-in if it is esthetic or complex case 8. Delivery Surveying the study cast Draw your RPD design on the study cast Objectives of Mouth Preparation When? After the preliminary diagnosis and the tentative treatment plan. Why? To Return the mouth to the optimum health state and eliminate any condition that could affect the success of the removable partial denture. 1-Surgical preparation. 2-Stabilizing Irritated tissue 3-Periodontal Treatment. 4-Operative and fixed restorations 5- Abutment teeth preparation 1- SURGICAL PREPARATION Extraction Non-restorable teeth Residual roots Impacted teeth • Malposed and over-erupted teeth when tooth preparation would not be sufficient to create space in cases of insufficient interocclusal space • Removal of hyper-plastic and flabby tissues to improve the quality of soft tissue support. • Muscle attachment and frena • Correction of knife-edge ridges to obtain the best bony support. • Removal of bony spicules, cysts, tori and deep undercuts 2- Stabilizing Irritated Soft Tissue Symptoms • Inflammation and irritation of mucosa • Burning sensation Causes • Ill-fitting denture • Lack of positive tooth support • Poor oral hygiene fungal/bacterial infection • Systemic disorders (eg. Uncontrolled diabetes • Habits (eg. Bruxism) Treat the problem first! Correction of the RPD • adjust occlusal errors • Proper extension of the denture base • Relief of the fitting surface Before treatment After treatment Treatment • • • • • Removal of the RPD Mouth rinse with warm saline 3 times/day Massage inflamed area with soft toothbrush Adjustment / correction of the RPD Tissue conditioning material – – – – Cushioning effect Massaging effect Allow even distribution of occlusal forces Must be changed every 4-7 days as needed PERIODONTAL PREPARATION Studies have shown that following periodontal therapy with good recall and oral hygiene program Properly designed RPD Little or no damaging effects on supporting structures Isidor and Jorgensen, 1990 Kappur et al., 1994 • The periodontal preparation of the mouth usually follows any oral surgical procedure and is performed simultaneously with tissue conditioning procedures. • If gross calculus accumulation is present, then debridement should be done before surgery to avoid dislodgment of calculus into the socket Objectives of periodontal therapy • Removal and control of all the etiological factors contributing to periodontal disease & elimination of bleeding on probing • Elimination or reduction of all pockets • Establishment of functional non-traumatic occlusion and tooth stability • Development of personalized plaque control program and definitive maintenance schedule Periodontal Diagnosis and Treatment Planning • Phase 1: Initial disease control therapy • Phase 2: Definitive periodontal surgery • Phase 3: Recall maintenance • Complete periodontal charting: – – – – Pocket depth Attachment levels Furcation involvement Tooth mobility • Pocket Depth/ bleeding on probing • Mobility: – Grade I: <1mm – Grade II: 1-2 mm – Grade III: > 2mm Reversible Tooth mobility is an indication of the condition of the supporting structures, namely the periodontium, and is usually caused by inflammatory changes in the periodontal ligament, traumatic occlusion, loss of attachment, or a combination of the three factors. • Complete intraoral radiographic survey – – – – – – Bone loss Furcation involvement Periodontal ligament space Lamina dura Caries Existing restorations and root canal treatment Phase 1: Initial Disease Control • • • • • • • Oral hygiene instructions . scaling and root planning . elimination of local irritating factors , other than calculus. Elimination of gross occlusal interferences. Guide to occlusal adjustment. Temporary splinting Use of night guard. Oral Hygiene Instructions • Good understanding of the patient of their periodontal condition • Motivation techniques • Soft medium toothbrush, disclosing wax, dental floss, interdental and/or sulcular brushes Further treatment should be withheld until a satisfactory level of plaque control is achieved Scaling and Root Planning • Removal of calculus and plaque deposits from the coronal and root surfaces of teeth • Ultrasonic scalers for calculus removal followed by decontamination of root surfaces by curettes Elimination of local irritating factors • Overhanging restoration margins • Open contacts • Proper treatment or temporization before completing the treatment sequence Elimination of Gross Interferences Correction of traumatic occlusion by occlusal adjustment (occlusal equilibration) to eliminate all cuspal interference which may be traumatic, either to the supporting periodontium or to the tissues underlying a denture base. Selective Grinding Temporary splinting • Indicator of prognosis of mobile teeth to decide whether to retain or extract. • Cause of mobility must be determined first then eliminated • Immobilization by composite resin, fiber reinforced resin, removable splints. Night Guard • Flat occlusal surfaces to eliminate lateral forces on mobile teeth • More helpful for abutment teeth which have been unopposed for long time to bring them gradually back to occlusion. Phase 2: Definitive Periodontal Therapy • Gingivectomy • Periodontal Flap • Mucogingival surgical procedures Phase 3: Recall Maintenance • For reinforcement of plaque control measures, oral hygiene instructions • Root planning, removal of subgingival and supragingival calculus Advantages of Periodontal Therapy 1- Elimination of periodontal disease --- primary etiologic factor of tooth loss. 2- Periodontium free of disease – much better environment for successful restorations. 3- Response of strategic but questionable teeth to periodontal therapy help in making final decision to exclude or include them in RPD Design. 3- Operative and Fixed Restorations Decayed teeth are restored with proper fillings.  It is recommended to restore carious abutment teeth with inlays or crowns. The rest seat is prepared in the wax pattern of the restoration. Reestablishment of Arch Continuity  Lone – standing tooth adjacent to an extension base area is termed a pier abutment.  Placing a clasp on such a tooth leads to periodontal destruction and abutment loss.  An appropriately constructed fixed partial denture is used to re-establish arch continuity. Occlusal rest seat on a crown. Cingulum rest seat on a crown. Correction of occlusal plane • Over eruption – If minor: enameloplasty – If moderate: cast restoration – If severe: extraction • Tipping: – If minor: enameloplasty – If moderate: cast restoration – If severe: extraction 5- PREPARATION OF ABUTMENTS Classification of Abutment Teeth 1. Teeth requiring modifications to coronal portion only 2. Teeth requiring restorations other than full coverage crowns 3. Teeth requiring full coverage crowns MODIFICATION OF ABUTMENTS 1. Guiding planes Parallel to each other AND parallel to the path of insertion and removal. Preparation of guiding planes in the abutment teeth Guiding plates found in the metal framework Functions of Guiding Planes: • Guide the prosthesis during insertion and removal. • Enhance Stabilization • Retention -- frictional resistance 2. Recontouring • Improve survey lines (improve clasp location) • Improve clasp retention (dimpling) • Improve the occlusal plane by grinding of the cusp tips and incisal edges of anterior teeth. 2. Recontouring in cases of excessive undercut. Height of contour 1. 2. Tooth alteration to lower the height of contour 0.01 inch undercut gauge 3. 4. *Recontouring in cases of excessive undercut. *Dimpling in cases of no undercuts. 3- REST SEAT PREPARATION Occlusal rest seat Cingulum rest seat Incisal rest seat Occlusal rest seat. The rest area should be prepared in: • sound enamel or • A restoration proven to resist fracture or distortion under loading – Gold inlays – Amalgam – Composite resin Occlusal rest seat If the abutment teeth are to be restored with inlays or crowns, the rest seat areas can be carved in the wax pattern of the restoration. 1- Outline 1- Triangular with deepest part of occlusal rest preparation towards the center of the tooth 2- The floor should be slightly inclined towards the center of the tooth. 3- The rest seat preparation should be concave (spoon or saucer shaped) to allow slight lateral movement, and this reduces the lateral stresses on the abutment teeth. The preparations is about 2 mm. 2 mm 1.5 mm 4- The margins of the preparation should be rounded. If a sharp marginal ridge is left, the rest is liable to break. 5- It should be broad at its attachment with the base. 6- The preparation should allow enough thickness for the rest without occlusal interference. *The path of the minor connector could also be prepared to give enough space for the minor connector. Cingulum rest seat *rounded inverted V-shape *at junction of middle and cervical 1/3 *The center is deeper bucco-lingually (positive rest) *used in maxillary canines. Contraindicated in mandibular canines *Most satisfactory when built in cast restoration Cingulum rest seat Incisal rest seat • On incisal Angles of Anterior teeth Outline: Rounded notch at incisal angle, deepest portion of preparation, apical to incisal edge Notch: Should be beveled lingually and labially If you have a choice, Which is better an incisal rest or a cingulum rest? Esthetics. Mechanics. Fence post principle. Summary Mouth Preparation for RPD 1- Surgical preparation. 2- Periodontal treatment. 3- Operative treatment. 4- Correction of occlusion. 5- Preparation of abutment teeth; to receive the partial denture that includes; a- Modification of abutment teeth. b- Rest seat preparation. Thank you