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inducation for fixed and removable partial denture
- 1. AHMED GAREBALLAH SALAH DIFFERENTIAL DIAGNOSIS: FIXED OR REMOVABLE PARTIAL DENTURES Total oral rehabilitation (disease management, defective tooth restoration, and tooth replacement) is an objective in treating the partially edentulous patient. Although replacement of missing teeth by means of fixed partial dentures, either tooth or implant supported, is generally the method of choice, there are many reasons why a removable partial denture may be the better method of treatment for a specific patient. 1
- 2. Indications for Use of Fixed Restorations • Tooth-Bounded Edentulous Regions - Generally any unilateral edentulous space bounded by teeth suitable for use as abutments should be restored with a fixed partial denture cemented to one or more abutment teeth at either end. The length of the span and the periodontal sup-port of the abutment teeth will determine the number of abutments required. - A span could be managed with the use of dental implants if deemed feasible and elected by the patientFor conventional fixed prostheses, lack of parallelism of the abutment teeth may be counteracted with copings or locking connectors to provide parallel sectional placementSound abutment teeth make possible the use of more conservative retainers, such as partial-veneer crowns, or resin-bonded-to-metal restorations, rather than full crowns. The age of the patient, evidence of caries activity, oral hygiene habits, and the soundness of remaining tooth structure must be considered in any decision to use less than full coverage for abutment teeth. 2
- 3. Cont. Two specific contraindications for the use of unilateral fixed restorations are known. One is a long edentulous span with abutment teeth that would not be able to withstand the trauma of non-axial occlusal forces. The other is abutment teeth, which exhibit reduced periodontal support due to periodontal disease, which would benefit from cross-arch stabilization. 3
- 4. Modification Spaces For a Class III arch, a removable partial denture is more effectively supported and stabilized when a modification area exists on the opposite side. In such cases, using a fixed partial denture to restore a lone-standing single-rooted abutment can stabilize the tooth and simplify the removable partial denture design. For Class I or II arches, an edentulous space anterior to a lone-standing abutment tooth exposes the tooth to excessive trauma from a distal extension removable partial denture. To protect the tooth, it is necessary to splint it to the nearest tooth. Additionally, abutment crowns should be properly contoured to provide the necessary support and retention for the removable partial denture. 4
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- 6. Anterior Modification Spaces - In a partially edentulous arch, missing anterior teeth are usually best replaced with fixed restorations, except in a Kennedy Class IV arch where only anterior teeth are missing. However, there are exceptions: sometimes a removable partial denture can achieve better esthetic results or simplify treatment, especially when excessive tissue and bone resorption make fixed restorations aesthetically challenging. Despite these exceptions, fixed restorations are generally preferred for anterior replacements due to their mechanical and biological advantages, as they simplify the replacement of missing posterior teeth with a removable partial denture and result in more satisfactory outcomes. 6
- 7. Replacement of Unilaterally Missing Molars (Shortened Dental Arch) - When replacing unilaterally missing molars, the choice of treatment must balance the impact on remaining oral structures with the potential long-term benefits. A fixed partial denture can be used, which may involve a cantilever prosthesis or dental implants. A cantilever-fixed prosthesis is suitable if only the first molar needs to be replaced, with minimal occlusion required. However, it is crucial to support the cantilevered molar with at least two abutments. - Alternatively, a removable partial denture, specifically a distal extension prosthesis, can replace missing molars. This approach involves connecting the edentulous side to components on the non-edentulous side. The effectiveness of this method can be affected by unfavorable leverage factors and potential issues with retainers. Consideration should be given to the opposing teeth to prevent extrusion and migration, which often outweighs the benefits of improved mastication. Additionally, the impact of the maxillary tuberosity should be evaluated, as leaving it uncovered may lead to enlargement and future occlusal issues. Covering the tuberosity with a removable partial denture base helps maintain its size and position, which may be preferable to leaving it uncovered. 7
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- 9. Indications for Removable Partial Dentures • Removable partial denture should be considered only when a fixed restoration is contraindicated, there are several specific indications for the use of a removable restoration. 9
- 10. Distal Extension Situations - For the retention and stabilization of a removable partial denture, if no space is available, abutment teeth can be modified with clasp assemblies or intracoronal retainers. Missing posterior teeth are often best replaced with a removable partial denture, especially when implants are not an option. Exceptions include cases where replacing second or third molars is not advisable, or where unilateral replacement of a missing first molar can be done with a multiple- abutment cantilevered fixed restoration or an implant-supported prosthesis. Common situations include Kennedy Class I and Class II, where an edentulous space on the opposite side of the arch can help in designing the denture. 10
- 11. After Recent Extractions - After recent extractions, replacing teeth with a fixed restoration is often challenging. Instead, a temporary removable partial denture is recommended, especially if a fixed restoration with natural teeth or implants will be constructed later. An all-resin denture is typically more cost- effective and easier to modify temporarily compared to a cast framework denture. As tissue changes occur post- extraction, tooth-bounded edentulous areas are best restored initially with removable partial dentures, which can later be relined to enhance esthetics, oral cleanliness, or comfort. Support for such restorations is provided by occlusal rests on the abutment teeth at both ends of the edentulous space. 11
- 12. Long span - A long-span removable partial denture can be adequately supported by abutment teeth if these teeth and the denture framework are sufficiently rigid. The support provided by the abutment teeth is similar for both removable partial dentures and fixed restorations. However, without cross-arch stabilization, the torque and leverage on the abutment teeth can be excessive. In such cases, a removable denture that gains retention, support, and stabilization from abutment teeth on the opposite side of the arch is generally recommended for effectively replacing the missing teeth. 12
- 13. Need for Effect of Bilateral Stabilization - In a mouth weakened by periodontal disease, a fixed restoration might compromise the future of the abutment teeth unless multiple abutments are used for splinting. Conversely, a removable partial denture can serve as a periodontal splint by providing cross-arch stabilization to weakened teeth. When abutment teeth are properly prepared and restored, a removable partial denture can offer greater benefits than a unilateral fixed partial denture in such cases. 13
- 14. Excessive Loss of Residual Bone - The pontic of a fixed partial denture should be aligned with the residual ridge while minimizing mucosal contact. In cases of significant resorption, a denture base can better position teeth to mimic natural dentition, as it is not constrained by the residual ridge's crest. This is especially useful for maxillary dentures. - In the anterior maxilla, resorption typically occurs labially, making it challenging to position artificial incisors naturally. A fixed partial denture might result in unnatural positioning and poor lip support, while a removable partial denture can use a labial flange to better position the teeth. The same approach applies to mandibular anterior teeth, where a removable partial denture can better align teeth with the lip and opposing dentition compared to a fixed partial denture, which might otherwise lead to esthetic issues due to ridge resorption. 14
- 15. Unusually Sound Abutment Teeth - When opting for a removable restoration to preserve natural teeth, it is essential to acknowledge that the prosthesis may lack stability and support without tooth modifications. To address this, the dentist should reshape and modify enamel surfaces to create guiding planes, occlusal rest areas, and optimal retentive and stabilizing components. These modifications not only enhance the function of the removable partial denture but also help maintain the health and durability of the natural teeth by ensuring a harmonious integration with the prosthesis. 15
- 16. Abutments with Guarded Prognoses - If an abutment tooth's prognosis is uncertain or worsens during treatment, it is crucial to design the removable partial denture with flexibility to adapt to potential changes. The design should anticipate the possibility of modifying or remaking the denture if the questionable tooth is lost. While adding a new tooth to a denture is relatively straightforward, incorporating a new retaining unit for a lost abutment is more complex. - To prepare for this, the denture can be designed to allow for future adjustments, such as adding an extension base if a posterior abutment is lost. This design should include provisions for indirect retention and flexible clasping. For anterior abutments, which pose greater challenges if they need to be replaced, it is often better to use more reliable abutments from the start, even if it means altering the initial treatment plan. 16
- 17. Economic Considerations • Ultimately, the choice of treatment must meet the economic limitations and personal desires of the patent. Economics should not be the sole criterion in arriving at a method of treatment. When for economic reasons, complete treatment is out of the question and yet replacement of missing teeth is indicated, the restorative procedures dictated by these considerations must be described clearly to the patient as a compromise and not representative of the best that modern dentistry has to offer. A prosthesis that is made to satisfy economic considerations alone may provide only limited success and result in more costly treatment in the future. 17
- 18. CHOICE BETWEEN COMPLETE DENTURES AND REMOVABLE PARTIAL DENTURES 18
- 19. Here's a concise summary in numbered points: 1. Decision Complexity: Choosing between complete dentures and removable partial dentures involves assessing tooth-related, functional, and patient-specific factors. 2. Prosthesis Differences: There is a significant difference between tooth-tissue-borne and tissue- borne prostheses, making the decision irreversible and complex for patients to conceptualize. 3. Tooth Evaluation: Evaluate remaining teeth for caries or periodontal disease and determine if they can survive at least 5 years with proper management, considering the added functional demand and risk of recurrent disease. 19
- 20. 4. Restoration Consideration: If teeth can be maintained, assess if they need restoration with surveyed crowns and how much they improve prosthesis support, stability, and retention. 5. Cost vs. Benefit: If prognosis is questionable, restoration costs are high, and prosthesis benefits are low, consider not maintaining the tooth unless the patient strongly desires it. 6. Retention Benefits: Retain teeth if they offer significant support, stability, and retention benefits, especially if the edentulous arch has unfavorable features (e.g., poor ridge form, high frena, etc.). 7. Preventive Value: Retaining teeth can prevent or delay age-related changes in the denture-bearing foundation, providing long-term benefits. 20
- 21. 8.Patient Preference: If a patient prefers a partial denture due to concerns about wearing a mandibular complete denture, their wishes should be respected, as long as the clinical factors are acceptable. 9.Interim Solutions: For patients who wish to retain teeth for a short period before transitioning to complete dentures, interim removable partial dentures can be recommended to aid in mastication, aesthetics, and ease of transition. 10.Retaining Anterior Teeth: Patients may desire to retain only six mandibular anterior teeth, which can offer aesthetic benefits and retention advantages. However, this can lead to stress on the anterior maxilla and require careful prosthesis maintenance. 11.Balanced Occlusion: To prevent issues with stress concentration on the anterior maxilla, balanced occlusion and regular dental maintenance are crucial. 12.Bilateral Tooth Retention: Retaining bilateral teeth, especially in similar locations, is more favorable for prosthesis design and function compared to asymmetrical tooth locations 21
- 22. 13. Patient Understanding: Clear communication with patients is essential to ensure they understand the functional differences between a complete denture and a removable partial denture. 14.Tailoring Treatment Plans: Listening to the patient’s desires during the examination process can significantly influence or change the treatment plan. The dentist should consider both the clinical aspects and the patient’s preferences when deciding between complete and removable partial dentures. 15.Effort to Retain Teeth: If patients strongly desire to retain their anterior teeth and they are functionally sound, the dentist should make every effort to accommodate this preference in the treatment plan. 22
- 23. REFERWNCES ALAN B. CARR and DAVID T. BROWN ; McCracken’s Removable partial denture 13th edition 2016 chapter 13 23