Bite Registration for Fixed and Removable Prosthodontics

Introduction

Reconstruction of a full arch can be challenging in clinical practice. As an increasing number of patients live longer, retaining their natural teeth becomes more difficult, and clinicians are regularly called upon to deliver dental restorations. Successful esthetic and functional dentistry depends on both the technician's and clinician's understanding of tooth morphology.

Bite registration is the process of capturing an accurate representation of a patient's upper and lower teeth in order to restore their dental condition. An impression of the patient's bite is the first step in establishing proper articulation of a dental model, which is used to diagnose movement-related problems. The goal is to obtain an accurate bite registration for the fabrication of a prosthesis, thereby avoiding adjustments upon cementation. Specialized materials for bite registration are essential to deliver rigid bite impressions. Different viscosities and set times are available; however, it is critical to select materials that provide ease of use and accurate results.

The objective of this study is to discuss proper bite registration for both fixed and removable prostheses, and to identify the important points that ensure an accurate fabrication of occlusal relationships in order to deliver the best clinical outcomes. The paper identifies different materials necessary for both fixed and removable prostheses, including modeling wax and Ramite polyether bite registration material.

Proper Bite Registration for Fixed Prosthodontics

The use of appropriate materials is critical for tooth preparation. When preparing a tooth for fixed restoration, it is essential to achieve an adequate amount of occlusal reduction in order to ensure long-term success. Fixed prosthodontics is a specialized branch of dentistry concerned with the replacement of missing teeth using cast prostheses that are permanently cemented in place (Elsevier Science, 2003). Fixed prosthetics typically covers:

• Crowns and temporary crowns
• Bridges and temporary bridges
• Veneers
• Inlays

To achieve effective and accurate bite registration for fixed prosthodontics, the following indications and contraindications must be considered.

Indications for Accurate Bite Registration in Fixed Prosthodontics

• One or two adjacent teeth are missing within the same arch.
• The patient's supportive tissues are healthy.
• Suitable abutment teeth are present.
• The patient is in good health and motivated to have the prosthesis placed.
• The patient has the motivation and skills to maintain good oral hygiene (Joshi, Shetty, & Prasad, 2013).

Contraindications for Accurate Bite Registration in Fixed Prosthodontics

• Necessary supportive tissues are missing or diseased.
• Suitable abutment teeth are not present.
• The patient is in poor health.
• The patient lacks motivation to have the prosthesis placed.
• The patient lacks adequate oral hygiene habits.
• The patient is unable to afford the treatment.

Procedures and Materials for Fixed Prosthodontic Restoration

Materials for Bite Registration of Fixed Prostheses

• Modeling wax (e.g., Hindustan modeling wax)
• Ramite, including 3M ESPE and Polyether Bite Registration Material
• Final prosthesis

Armamentarium

• Articulated casts
• Rubber bowl
• Mixing pad
• Mixing spatula
• Thermometer
• Lacron's carver
• Wax gauge (e.g., Essago SBC German stainless)
• Metal gauge (e.g., Essago SBC German stainless)

Shade Selection

• A shade guide should be used to match the natural color of the teeth.
• Adequate moisture should be maintained to achieve a more accurate shade match.
• Natural sunlight should be used when possible.
• The patient's chart must be recorded using the laboratory prescription.

Tooth Preparation

The tooth should be prepared using cast restorations that can slide into place and withstand occlusal forces. Rotary instruments should be used to reduce the contour and height of the tooth. Both rotary and hand cutting instruments are used to prepare the gingival margins.

Retention Aids

When teeth are extensively decayed, endodontically treated, or fractured, additional retention aids must be provided. These include:

• Pin retention
• Post and core
• Core buildup

Tissue Management and Gingival Retraction

Retraction cord is used to temporarily displace gingival tissue and widen the gingival sulcus, allowing free flow of impression material around the prepared tooth. Cord may be nonimpregnated or impregnated.

Final Impression

Elastomeric impression materials should be used to create highly accurate impressions. The recommended procedure is as follows:

• Mix and apply a light-bodied material around the patient's prepared tooth.
• Mix and load the tray with a heavy-bodied material and place it onto the arch or quadrant.

Bite Registration

The bite registration step in fixed prosthodontics provides the laboratory technician with a reproduction of the patient's teeth to design the anatomical structure of the patient's fixed prosthetic, accommodating both open-bite and closed-bite relationships.

Provisional Coverage

Provisional coverage keeps patients comfortable from the time of tooth preparation until the final cementation of the fixed prosthetic. The purposes of provisional coverage include:

• Reducing discomfort and sensitivity
• Maintaining esthetics and function
• Protecting the tooth margins
• Preventing tooth shifting

Laboratory Prescription

The laboratory prescription should include a precise and detailed order from the dentist directed to the laboratory technician, with a full description of the teeth restoration model to be fabricated.

Delivery

Once the dentist accepts the casting, it is cemented to the patient's tooth using either permanent or temporary cementation.

Home Care Instructions for Fixed Prostheses

Good home care is critical to the maintenance of a fixed prosthesis. Patients must carefully brush their supporting tissues and the fixed prosthesis daily.

Conclusion

An increasing number of people will require dentures — known as false teeth — to replace missing teeth. Conventional denture technique is removable, though other designs can rely on clasping and bonding onto dental implants. Proper bite registration is critical to avoid adjustments upon cementation. This paper discussed several strategies for bite registration across both fixed and removable prosthetic modalities. Removable partial dentures are appropriate for patients who have lost some of their teeth, while fixed partial dentures — bridges and crowns — are fitted onto the remaining teeth. Accurate bite registration, supported by appropriate materials such as modeling wax and polyether bite registration material, is fundamental to achieving optimal esthetic and functional outcomes for patients.