Understanding bite registration

According to GPT - the Maxillomandibular relationship record is defined as - A registration of any positional relationship of the mandible relative to the maxilla.1 The bite registration technique is a cornerstone in prosthodontics, especially in edentulous patient treatment.

Jaw relation - the spatial relationship between the maxilla and mandible.

Proper dental bite registration results in a prosthesis that harmonises with the patient’s natural mandibular movements, enhancing comfort and functionality.

Challenges in bite registration for Edentulous Patients-

Missing natural teeth.
Variability in vertical dimensions at rest and occlusion.
Decreased neuromuscular coordination.
Movement of dentures during the recording process.

Bite registration Techniques

Types of Jaw Relations:

1-    Orientation jaw relation – using facebow2

2-     Vertical relation:

Rest Vertical dimension (VDR).
Occlusion Vertical dimension (VDO). 

3-  Horizontal relation:

1. Centric jaw relation

·   Functional (chew-in) methods.

·   Graphic method.

            Intra-oral method.

            Extraoral method. (Gothic arch tracing)

·   Tactile or inter occlusal rim check record method

b. Eccentric jaw relation:

·  Protrusive relation

·  Lateral jaw relation

These methods, combined with a detailed assessment of patient-specific anatomy, aid in creating reliable prostheses.

Gothic arch tracing

The extra-oral is preferable to the intra-oral tracing in recording horizontal jaw relation because the extra-oral is more accurate, visible, and larger than intra-oral tracing. The graphic methods record a tracing of mandibular movement in the horizontal plane. In Gothic arch tracing; a table coated with carbon or wax is attached to the maxillary record base and a tracing needle is attached to the mandibular record base.

When the mandible movement is obtained the tracing needle draws a figure on the tracing table, this figure is known as the Gothic arch tracing, also known as arrow point tracing. The apex of the tracing arrow represents the centric relation position, with the two sides of the tracing arrow representing the limits of lateral movements.

Occlusal Wax Rims

Occlusal wax rims are indispensable for recording jaw relations in edentulous patients. Their role is:

Recording vertical dimensions:
Supporting facial contours: Providing lip and cheek support to achieve aesthetics.
Establishing occlusal planes.

While shaping occlusal wax rims:

Use the fox plane to achieve parallelism with interpupillary and ala-tragus lines.
Adjust to achieve appropriate lip support and occlusal height.
Contour to match the patient's natural arch form and function.

Step-by-step guide to Edentulous Bite Registration

Clinical step; During the initial clinical appointment, primary impressions were taken using reversible hydrocolloid impression material.

Laboratory step; After obtaining the impressions, a cast was poured using type 2 or type 3 gypsum material. A thin wax sheet, 1.5 mm thick, was then adapted, and a special tray was fabricated for border moulding.

Clinical step; Border moulding was performed using low-fusing impression material (type 1), followed by taking a second impression with zinc oxide eugenol paste.

Laboratory step; The impression trays were beaded and boxed, and a master cast was fabricated. A denture base was created on the master cast, and occlusal rims were constructed on this base.

Clinical step; Jaw relations were recorded using the occlusal rims.

Laboratory step; The sealed occlusal rims were mounted on an articulator, and teeth arrangement was completed in the laboratory.

Clinical Step; A wax try-in was conducted.

Laboratory Step; A clean wax-up was done, followed by de-waxing and packing with heat-cure acrylic resin. The dentures were then cured, finished and polished.

Clinical Step; The denture insertion is done.

Challenges in Traditional Jaw Relation Techniques

Inaccuracies: Manual recording of jaw relation often leads to inconsistencies.
Multiple Visits.
Patient Compliance.
Material limitations

EDENTULOUS BITE REGISTRATION - Future Trends and Digital Innovations

1. Introduction of Digital Dentures6

Digital Innovations uses intraoral scans and CAD/CAM techniques with advanced software for precision modelling and manufacturing. The use of computer-aided design and computer-aided manufacturing (CAD-CAM) technology in complete denture fabrication has better features as dentures are more retentive with better fit.

Fewer visits for procedures increase patient and clinician satisfaction.

Primary Impression Scanning: Eliminates the need for physical models.
Virtual Articulators: Simulate mandibular jaw movements for accurate bite registration.
New Improved Materials: High-quality resins improve the durability and aesthetics of the prosthesis

2. Systems in Practice

Weiland Digital Denture System:

Combines five-axis computer-aided milling along with virtual modelling.
Involves functional impressions and digital occlusal rim design.

AvaDent System:

Features a fully digital workflow from scanning to final denture production.
Offers virtual try-ins for pre-fabrication adjustments.

Baltic Denture System:

Requires just two appointments, focusing on functional impressions and milling.

Do digital procedures have the same level of accuracy as conventional techniques? 

A detailed examination of dental CAD/CAM technology reveals its potential to significantly improve bite registration processes by enhancing precision and efficiency.

Benefits of Digital Bite Registration

Efficiency by reducing the number of visits
Precision- automatic software system reduces human error
Non-invasive scanning techniques

Limitations and Challenges

Technical Dependence: Errors in software or machinery can delay production.
Material Constraints: Current biocompatible resins may not suit all patients.
Cost: Initial investment in digital equipment can be high.

Weiland Digital Denture System

This system is specifically designed for completely edentulous patients and comprises a five-axis milling machine integrated with a laboratory scanner and design software, streamlining the denture fabrication process into four clinical sessions interspersed with three dental laboratory stages.

Clinical Step – 1

The first clinical session of denture design includes three stages

1-Primary Impressions: Taken using alginate, although optical impressions of the edentulous arch can be used, they remain time-consuming and offer limited advantages.

2- Preliminary Inter-arch Sapce Recording: The device records the preliminary interarch relationship.

UTS CAD Device - Used as a Fox plate to measure deviations from reference planes, the UTS CAD device is attached to the Centric Tray. Digital deviation values are measured and transferred to a virtual articulator, positioning the virtual primary models in space.

Final session: Dentures are tried, and primary equilibration is performed. If all previous steps were followed correctly, the equilibration session is usually unnecessary or straightforward.

Conclusion

Accurate jaw relation techniques are vital for successful prosthesis fabrication. By understanding the principles, challenges and evolving innovations, clinicians can ensure optimal outcomes for their edentulous patients. The future of dental bite registration and prosthodontics lies in new technology while mastering traditional techniques\

FAQs

What is Dental bite registration, and why is it important for edentulous and dentulous patients?

Bite registration records the spatial relationship between the upper and lower jaws, crucial for ensuring proper alignment and function of dentures in edentulous patients.

How does digital bite registration differ from traditional Bite registration methods?

Digital bite registration uses scanners and software for precise and repeatable recordings, reducing errors associated with manual techniques.

What are the common challenges in bite registration for edentulous patients?

Challenges include a lack of natural teeth for reference, unstable record bases, and patient-specific anatomical variations.

How long does the bite registration process take?

The duration varies based on the method used but typically ranges from 30 minutes to 1 hour.

REFERRENCES

1.       The glossary of prosthodontic terms. (2017). The Journal of Prosthetic Dentistry, 117(5).

2.       Zarb, G. A., Hobkirk, J., Eckert, S., & Jacob, R. (2013). Prosthodontic treatment for edentulous patients. 13 ed. Mobsy; 9-1.

3.       Carlson G.E. Boncher's prosthodonotic treatment for edentulous patient 11th edition 1997.

4.       Kaya, K. S., Türk, B., Cankaya, M., Seyhun, N., & Coşkun, B. U. (2018). Assessment of facial analysis measurements by Golden Proportion. Brazilian Journal of Otorhinolaryngology, 85(4), 494–501.

5.       Digital Dentures Current Techniques In Cad/ Cam Denture Fabrication- A Review. . IOSR Journal of Dental and Medical Sciences 2279-0861.Volume 23, Issue 6 Ser. 10 (June. 2024), PP 01-05.

6.       John Av, Abraham G, Alias A. Two-Visit Cad/Cam Milled Dentures In The Rehabilitation Of Edentulous Arches: A Case Series. The Journal Of Indian Prosthodontic Society. 2019 Jan 1; 19:88-92.

7.        Kerstein RB. Current applications of computerized occlusal analysis in dental medicine. Gen Dent 2001; 49:521-30

8.       P. Paul et al. Evaluation of efficacy of digital or virtual bite registration over conventional techniques- A systematic review.Journal of Oral Biology and Craniofacial Research 14 (2024) 785–792.

9.       Digital dentures: A protocol based on intraoral scans Lucio Lo Russo, DDS, PhD,a Angelo Salamini, Eng,b Giuseppe Troiano, DDS, PhD,c and Laura Guida, DDS

10.   A new digital denture procedure: a first practitioners appraisal Guillaume Bonnet1,2, Cindy Batisse1,2, Marion Bessadet1,2, Emmanuel Nicolas1,2* and Jean-Luc Veyrune1,2