Overdenture Solutions: Enhanced Stability and Patient Comfort

Understanding Overdentures

An overdenture is a complete or removable partial denture whose base covers one or more retained teeth and/or one or more dental implants. It is designed to provide enhanced stability, retention, and support, and typically requires a retentive system.

Key Features and Support Options

Overdentures offer a removable prosthetic option, utilizing remaining natural teeth or supported by dental implants.

Advantages Over Conventional Dentures

• 1. Alveolar Bone Maintenance: Retained roots convert compressive forces into tractional forces, helping to preserve alveolar bone.
• 2. Increased Masticatory Forces: Overdentures significantly improve chewing efficiency and force.
• 3. Enhanced Tactile Discrimination: The periodontal ligament (PDL) of retained teeth provides proprioceptive feedback to the brain, improving sensation.
• 4. Tooth Maintenance: Even teeth with a poor prognosis can be used as abutments, provided there is a minimum of 5mm of surrounding bone.
• 5. Improved Stability, Retention, and Esthetics: The design, often horseshoe-shaped, offers superior stability, retention, and a more natural appearance.
• 6. Fewer Prosthetic Adjustments: Generally requires less frequent adjustments compared to conventional dentures.

Potential Disadvantages

• 1. Economic Cost: Can be higher due to the need for abutment teeth preparation and specialized retention systems, often involving gold alloys.
• 2. Vertical Dimension (VD) Limitations: Patients with a low vertical dimension may not have sufficient space to accommodate the male and female components of the retentive system.
• 3. Maintenance Challenges: Plastic female components may require replacement, and relining can be more complex when abutments are positioned within the tissue-bearing surface.

Indications for Overdentures

• Doubtful abutment teeth that can still be preserved.
• Patients with a low ability to adapt to conventional removable complete dentures (RCD).
• To maintain remaining teeth for alveolar bone preservation.
• Cases of extreme tooth wear.
• Patient refusal of dental implants.
• Maxillofacial congenital or acquired defects.
• Congenital disorders resulting in a reduced number of permanent teeth, such as anhidrotic ectodermal dysplasia.

Contraindications for Overdentures

• Abutment teeth that do not meet periodontal or endodontic health requirements.
• Unsuitable abutment distribution.
• Significantly reduced interocclusal space (vertical dimension).

Abutment Tooth Selection Criteria

1. Periodontal Health: A minimum of 5mm of supporting bone around the tooth is ideal.
2. Endodontic Status: Assess for any periapical pathology, such as cysts.
3. Number and Position: Ideally, abutments should be symmetrically distributed for optimal support.
4. Root Shape: Flat and curved roots offer better stability than conical roots.
5. Opposing Dentition: Evaluate the forces from the opposing arch. Forces are generally lighter with conventional dentures, but tactile discrimination is present with implant-supported overdentures.

Abutment Tooth Preparation

Preparation typically involves endodontic treatment and shaping for a post to ensure root anchorage. A healing period of 1-2 months after endodontic treatment can help reduce lever forces on the abutment. The preparation should generally not exceed 2-3 mm, except when preparing for a telescopic crown. For a weak tooth, the root can be retained to preserve the alveolar ridge, provided there are no cysts. For a strong tooth, a double crown system may be utilized.

Overdenture Maintenance and Care

Proper maintenance is crucial, starting from the time of denture prosthesis delivery.

Hygiene Guidelines

• Patient Motivation: Emphasize the importance of consistent oral hygiene.
• Brushing: Brush abutments with toothpaste after every meal.
• Flossing: Floss around abutments if space allows.
• Interproximal Brushing: Use interproximal brushes for bar-supported systems.
• Disinfection: Immerse the overdenture in a suitable disinfectant (e.g., Corega tabs) for one hour, then clean thoroughly with water.

Insertion and Removal Guidelines

Avoid using excessive force during insertion or removal, and do not bite the denture into place. Always insert the overdenture using your fingers, preferably in front of a mirror, to ensure proper seating.

Night Use Recommendations

Generally, overdentures should not be worn at night, allowing tissues to rest. An exception may be made for bruxist patients, where the overdenture can act as a protective appliance.

Follow-Up Schedule

• Initial Review: 6-12 months after delivery.
• First-Year Reline: Consider a reline between 6-8 months during the first year.
• Annual Review: Subsequent reviews should be conducted at least once a year.
• Abutment Scaling: Scale abutments as needed to maintain periodontal health.
• Retention Adjustment: If retention is lost, reactivate or replace the plastic female components as required.