Dental Prosthetics Quiz

Restorative Dentistry 3: Replacing Teeth

• Treatment planning for patients with missing teeth involves considering the number, location, and function of missing teeth, and the patient's preferences. A minimally invasive approach is preferred. 21 or more teeth are considered the minimum for functioning dentition, though this can vary by age, pattern of tooth loss, and incisal relationship. Replacement isn't always necessary.

• Bridges are a fixed option, advantages include their fixed nature, while disadvantages include the destruction of natural tooth tissue, cost, and clinical time, which can be lengthy. Resin-bonded cantilever design is minimally invasive. Implant-supported prostheses can be fixed or removable, offer advantage avoiding natural teeth prep, however, are expensive and require surgical procedures with high predictability if planned and executed carefully. Removable partial dentures require minimal tooth preparation. They may have less expense but can contribute to plaque accumulation and damage to soft tissues/teeth.

• Complete immediate dentures are indicated for patients with failing remaining teeth. Complete dentures require patient cooperation and good clinical management. Successful dentures are also dependent on patient compliance and technical management.

• Treatment planning for missing teeth prioritizes a detailed patient history to understand patient goals and past experiences with dentures, alongside medical history to assess their capability to cope with dentures and impacts on medical factors like, for example, if a drug lowers saliva flow. Social history should also be considered for travel and other social arrangements. Clinical examination includes assessment of pathology, existing restorations, periodontium, edentulous areas (ridge form and extent), mucosa compressibility, tongue size, and saliva viscosity, and evaluation of previously unsuccessful dentures.

• Specific design problems for bridges include periodontally involved abutment teeth requiring periodontal treatment first before consideration of bridgework, pier abutments requiring a support for pontics on each side, consideration of tilted abutments that should be addressed via orthodontic treatment, or a split bridge. All design problems require careful consideration of patient factors to decide on suitable design and potential advantages and disadvantages.

Bridge-design

• Evaluate the prognosis of all teeth in the vicinity to avoid unnecessary extractions. Assess abutment teeth (consider restoration, endodontic status, periodontal condition, and mobility) select a design for retainers (e.g., full or partial crown), consider pontics and connectors, and generate a list of possible bridge designs.

Bridges-practical stages

• Comprehensive patient history and evaluation (TMD, OH, diet) are critical. Diagnostic mounting involves taking accurate impressions of both arches, facebow record, and mounting models on a semi-adjustable articulator (or using ICP, RCP, mounting).

• Performing a diagnostic wax-up is necessary to simulate the final restoration on the models to evaluate aesthetics and occlusion. This wax-up also enables a silicone putty impression to be made to create the temporary bridge.

• The abutment teeth preparations are closely examined to check for parallelism. Temporary bridges are used to mimic the final design and can be laboratory-made or matrix-cut from the wax-up.

Bridge Failures

• Common failures include loss of retention, mechanical problems (i.e. casting), and issues with the abutment teeth (e.g., caries, periodontal disease, loss of vitality).

• Management of failures considers options like repair or replacement depending on the extent and type of failure. A thorough analysis of the cause is required before any replacement.

Resin-bonded bridges

• Classification, anterior and posterior. Resin-bonded bridges require a cast metal structure that's bonded to abutment teeth using adhesive resin. This technique is most effectively used in cantilever designs, with one abutment and one pontic, and is often less expensive while needing minimal tooth preparation.

Removable partial dentures--principles

• Components of the denture include a saddle (area resting on the missing arch/teeth and that carries artificial teeth/gumwork), connectors, an area that joins the parts of the denture together, support (resistance to vertical forces towards the mucosa), and retainers (Components that prevent displacement).

Removable partial dentures-design

• Survey to establish path of insertion, which undercuts for retention, for smooth processing.

• Assess retention via direct or indirect ways, via clasps, guide planes, soft tissue undercuts or precision attachments.

• Assess bracing with the maximum extension of the saddle and connector design and its adaptation.

Removable partial dentures--clinical stages

• Record initial impressions using alginate or other material in a stock tray. Record occlusion, considering occlusal stop. Record second impressions using special trays. (Alginate or elastomer). Prepare and check the trial/waxed denture.

Immediate complete dentures

• Consider if patient requires transition from partly-to-fully-edentulous. Assess whether immediate dentures or partial dentures can successfully adapted. Immediate dentures provide an advantage in copying existing teeth and their shape, allowing more rapid adaptation.
• Consider whether patient will require early replacement.
• Extraction of the majority of posterior teeth to maintain OVD/occlusion, and subsequently fitting of immediate dentures once healed. Directly following tooth extraction, it may be easier to use immediate dentures, while gradual extraction and adaptation may be more suitable where a significant period of healing is needed.
• A clinical procedure requires taking preliminary and second impressions (using alginate or silicone), recording occlusion (using a method appropriate to the patient's condition, e.g., existing teeth), and trial insertion of the dentures.

Complete dentures--principles

• The focus is on retention and stability. Retention concerns the resistance to displacement. Stability relates to resisting displacing forces during function. Important considerations for retention include peripheral seal, fit, contact area, and saliva viscosity/volume. Important considerations for stability include forces acting on the polished and occlusal surfaces.

Complete dentures--impressions

• Use both stock trays and alginate or elastomer (or impression compound) for preliminary impressions, and ensure appropriate special trays are prepared to ensure enough space for the material.
• Record master impressions to capture the maximum denture-bearing area and create a stable border seal.

Complete dentures--trial insertion

• Trial dentures are wax-constructed on acrylic or shellac bases.
• The dentist checks the trial dentures (via individually testing both the dentures and their fit, and finally, testing them both together checking for extension, stability and position).
• Final check of the trial dentures, including vertical and occlusal dimensions should be done.

Denture maintenance

• Regular check-ups/reviews to assess/manage ill-fitting dentures are necessary for long-term maintenance of effective dentures.

• Rebasing of dentures can be performed if the existing fitting surface is worn-down.

• Cleaning/hygiene maintenance is crucial for preventing plaque build-up, stains, and calculus to prevent illness and ensure a pleasant experience for the patient. Important to emphasize the need for thorough cleaning with soap and water, and to recommend using appropriate denture cleaners.

Denture problems and complaints

• Pain from a flaw in the fitting surface to the occlusion to problems with existing teeth,
• Loose dentures can be caused by errors in fitting surfaces, incorrect occlusion or lack of structural support, which can lead to an unstable occlusal condition,
• Burning mouth can be caused by errors in the OVD, or related to the dentures,
• Evaluation of speech difficulties caused by excessive extension or inaccurate position of teeth.

Candida and dentures

• Oral candidiasis (Candida infection) is common in denture wearers and can be caused by factors like poor denture hygiene, night-time denture use, and systemic factors.

• Initial evaluation requires a dental and medical history review to understand factors/conditions that may exacerbate oral candida.

• Appropriate management includes advising the patient to remove their dentures at night, maintain thorough fitting surface cleaning of their dentures, and suggest reducing sugar intake.

Denture copying

• Denture copying methods involve creating a replica of a patient's existing denture(s) to be used as a guideline to create new dentures.

Overdentures

• Overdentures (ODs) can improve retention, stability, support, and aid transition from partial to full dentures (F/F).
• Advantages include preservation of bone and tooth structure, and some degree of preserving proprioception.
• Involves selecting specific abutment teeth, considering need for root canal treatment (RCT).
• Clinical procedure (for abutment teeth prep consideration) involves root canal treatment if impacted, and fitting and recording of the impressions.

Dentistry and the older patient

• Age changes impact oral health (e.g., bone, mucosa, teeth),
• Challenges include age-related physical and systemic changes, medication impacts, and access to care.
• Modifications may be required for denture maintenance that take these changes into account.

Age changes

• Age changes in oral soft tissues, dental hard tissues, dental pulp, periodontium, and systemic immune system are common.

• Changes are related to ↓ microcirculation, ↓ cellular reproduction, ↓ tissue repair, ↓ metabolic rate, and ↑ fibrosis.

• These factors all contribute to oral/medical issues for the elderly.

Dental care for the elderly

• Management of older patients requires careful consideration of medical history and communication.
• Access and timing of appointment options must be considered.
• Modifications to the dental chair are necessary to ensure appropriate positioning and support, considering physical/health conditions and mobility.