Periodontal Considerations of FPD PDF

‫بسم هللا الرحمن الرحيم‬ Periodontal Aspects of FDP By Prof. Dr. Lamia Dawood Introduction: The preservation of periodontium during bridge work is of prime importance. Periodontal diseases should be avoided during construction of bridge and after bridge cementat...

‫بسم هللا الرحمن الرحيم‬ Periodontal Aspects of FDP By Prof. Dr. Lamia Dawood Introduction: The preservation of periodontium during bridge work is of prime importance. Periodontal diseases should be avoided during construction of bridge and after bridge cementation. It is better to prevent periodontal diseases rather than treat them. The inadequate reproduction of proper anatomical form in artificial crowns → periodontal disease.  Peridontium: It is a connective tissue structure that anchors the teeth in the mandibular and maxillary alveolar processes. Periodontal ligament consists of collagenous fibers embedded in bone and cementum, giving support to the tooth in function.  The clinical gingival sulcus depth normally measures 1-2mm The epithelial attachment is 1mm and the connective tissue attachment 1-2mm. The alveolar crest is therefore located at 2mm apical to the base of the sulcus. PDLD should be treated before starting the prosthetic phase of treatment. A. Phase 1 Therapy: 1. Scaling + Root Planning 2. Oral Hygiene measures Waterpik 3. Removal of defective restorations 4. Evaluation of teeth with mobility: (Assessed clinically and Radiographically)  Evaluation of teeth with mobility: Grade I: < 1mm BL —— can be used as abutments Grade II: 1-2 mm BL —— CI Grade III: > 2mm BL + Vertical Movement —— CI Hopeless → Extraction Causes of Tooth Mobility: PDLD Primary cause to bone loss. Occlusal Trauma Treatment of Teeth Mobility Identify the cause first. PDLD → removal of plaque and Root planning. Primary Occlusal Trauma → Removal of interference. Increased bone loss that affects chewing and esthetics → Splinting. The health of periodontium during FPD construction depends on I. Axial contours. II. Restoration margin. III.Occlusal morphology. IV. Pontic design.  I. Axial contours: A. Facial and lingual contours. B. Proximal contours. A. Facial and lingual contours: The height of contour of the restoration is very important for healthy periodontium Size of the normal bulge as measured from cervical line level Anterior teeth: 0.5 mm. Premolars: 0.7 mm. Molars: 1 mm.  Position of height of contour: Posterior teeth → at cervical 1/3 except lingual surface of lower posterior teeth → at the middle third.  Emergence profile: The infra bulge area is called emergence profile. Emergence profile is either concave or straight. Better straight for hygiene measures. Never convex as this interferes with oral hygiene measures. Faulty design of height of contour: Over-contoured restoration → deprive the gingiva from normal massage. Under-contoured restoration → trauma to the soft tissue. Emergence profile convex anatomy → prevents oral hygiene measures.  Proximal contour: Contact area is critical for the health of the periodontium. Location of proximal contact: Occluso gingival. Bucco-lingual. The lingual embrasure is therefore wider. Dental floss pass with slight resistance. Occluso-ginigval dimension of proximal contact A; correct. B; large. C; small. Faciolingual dimension of proximal contact A; correct. B; broad. C; narrow.  Faulty proximal surfaces’ design can be: Broad proximal contact: Crush the soft tissue filling the embrasure → inflammation. Narrow contact: Enlarges the embrasure causing insufficient protection of soft tissue. Embrasures should be large enough for dental floss to pass through.  II- Restoration Margins: 1. Margin position: Spragingival. Equigigival. Subgingival. Deep Subgingival Margin (= Margin < 2mm away from bone crest) → Inflammation → Bone resorption → Infra-bony pocket formation. 2. Margin Adaptation: The junction between cemented restoration and the tooth is always a potential site for recurrent caries. Acrylic resin margins → rubber wheel and pumice or polishing agent. Porcelain margins → by Dedeco kit. Gold margins → rubber wheel and Rouge. 3. Margin Configuration: Definite FL (Shoulder, chamfer,…) or Indefinite (knife edge). III- Occlusal morphology: Periodontium tolerate occlusal forces // the long axis of the tooth. Lateral and torque forces → bone resorption and deposition. When there is an increased functional demand upon the periodontium, it commonly accommodates these forces. Primary Occlusal Trauma: Pathologic lesion created by a force enough to disturb a normal intact periodontium. Secondary Occlusal Trauma: A lesion created by a normal function on weaker periodontium.  The effect of occlusal forces on the periodontium depends on Magnitude of the falling forces: Decreased force as in case of: Loss of opposing dentition Presence of partial denture in the opposing Increased forces as in case of: Premature contact in centric or eccentric relation: This could occur due to: Long standing edentulous spans. Faulty occlusal design in a restoration. Orthodontic treatment. Load direction: Best tolerated forces ┴ forces. Lateral forces → torque. Rotational and lateral forces → areas of pressure and tension in the periodontium. Pressure → bone resorption, while tension → bone deposition.  Force duration: A) Continues forces: Para-functional habits → no chance for repair. B) Intermittent forces: Better tolerated by the dentition → allow time for repair. Frequency of force: In case of cyclic forces. High frequency forces are associated with short rest time → destructive.  IV- Pontic design: Pontic affect the periodontium through 2 aspects: 1. Material: Composition of the material. Finishing of the material. 2. Design: Gingival surface. Occlusal surface. Axial contours.  Occlusal surface of the pontic: Different concepts exist: 1. The occlusal dimension is reduced 1/3-1/5 of its buccolingual width to decrease the forces. Eccentric forces are not reduced. These forces are very dangerous. 2. Occlusal table is constructed with its normal dimension. This will protect the soft tissues during mastication. Properioceptive receivers protect the tooth against high un-tolerated forces. 3. Minimize forces by decreasing cuspal inclines, fossae depth, and grooves.  Mesial and distal surfaces Proximal contact Connector: should be: Elliptical in shape Concave to adapt to the proximal surface Material with enough strength Allow for enough embrasure size Treatment of mobile abutments Splinting Is the procedure of connecting the abutments to stabilize and redistribute the load. Indications: 1- To protect the loose or mobile teeth from injury. 2- To redistribute occlusal forces in a more favorable way to decrease the forces falling on a particular tooth. 3- To prevent super eruption and migration. 4- It is common with implants. 5- Stabilization after trauma. Advantages of splinting: 1. Redirecting the forces on the abutment teeth in a favorable directions. 2. Redistribution of forces on more than one tooth. 3. Prevention of super eruption and migration of teeth. 4. prevent lateral forces which is destructive to the periodontal ligaments. 5. Single rooted teeth begin to function as multi rooted teeth as the fulcrum and the center of rotation is changed.  The number of teeth required to stabilize a mobile tooth depends on: 1. The degree and direction of the mobility. 2. The amount of the remaining supporting bone. 3. The location of the mobile tooth. 4. Function of the tooth, whether it will be used as an abutment for a FPD. 5. It is better to use more than one stable tooth to splint one mobile tooth. 6. The more mobile teeth involved, the greater the number of abutments needed to stabilize them. 7. When a bridge is used and the distal abutment needs splint, multiple added anterior abutments should be used.  Types of splints 1- External devices which are ligated or fixed to intact tooth surface. 2- A splint or circumferential wiring. 3- Removable appliances: a- Hawley splint. b- A continues clasp partial denture. c- A swing lock partial denture. 4- Provisional full coverage occlusal acrylic splint. A) Temporary and provisional splints B) Permanent splint 1- Removable splints. 2- Rigid connectors: a combined periodontal and prosthetic treatment. 3- Non rigid connectors: these are precision dove tail lock design. 4- Telescopic crown: it involves covering the prepared teeth with a thin gold coping that incorporates shoulder gingival margin on which a superstructure will be abutted. The surface of the coping will not be polished for better retention. Swing lock RPD Continuous clasp RPD Restoration of periodontally compromised teeth  Management of Furcation Involvement Grade I: Vertical loss < 3mm. up to 1mm horizontal. not evident on x-ray.  Grade II: Vertical loss > 3mm. > 1mm horizontal. Evident on x-ray.  Grade III: Vertical loss > 3mm. Horizontal through & through. Evident on x-ray. May or may not be occluded by Gingiva.  Grade IV: Vertical loss > 3mm. Horizontal through & through. Evident on x-ray. Not occluded by Gingiva. Management of Furcation Involvement Treatment Grade I, II → Scaling, root planning, OHM (Oral Hygiene Measures), gingivectomy. Grade III, IV → Recontouring of teeth or bone. Tunneling → in severe grade II & III. Root Amputation/ Root Resection/ Hemisection in multi-rooted teeth. Root Amputation: Removal of a root without touching the crown. Endo ttt then resection. Crown contours differ to allow cleaning. Post and core if needed. Finish line should cover the obturated pulp chamber.  Maxillary MB Root Maxillary Palatal Root  Mandibular Hemisection  Teeth that have been saved by periodontal therapy often need extra-coronal restorations All periodontal diseases must be treated first before any prosthetic procedure Six to eight weeks of healing time is needed before the gingival termination of the tooth preparation is completed  Problems of periodontally compromised teeth include: 1. Poor crown/root ratio. 2. Esthetic compromise. 3. Furcation invasions. 4. Progressive tooth mobility and migration. 5. Inadequate zone of attached gingiva. 6. Prominent root concavities.