Inter occlusal Record (Bite Registration) Dr. Maha anwer Agha MSC,pHD

Bite registration is a technique done to transform the relation between the upper & lower dental arch from the patient mouth to the articulator.

Proper interocclusal record is important to orient the die or dies of the prepared & unprepared teeth in the same arch to the opposing arch.

Bite registration allow the dentist to observe accuratelly tooth contact, occlusal discrepencies and to fibricate restorative procedure for the patient without in changing occlusion

Its important to establish and transfer the relation ship between the maxillary and mandibular dental arches that exists when the condylars are in the posterior superior position in the glenoidfossa to an articulator using a bite registration materials

Centric relation is the physiological position of the condylar head of the mandible (without stress) from which all other movement is initiated. Centric relation is taken when no enough occlusal stops are left after teeth preparation especially in cases of full mouth rehabilitation of fixed partial denture. Including distal terminal abutments unilaterally or bilaterally. In centric relation it must not perforate the registration material

Centric relation: It is an arch to arch (mandible to maxilla) relationship when the condyles are in their terminal hinge axis (on the most superior posterior position) in the glenoid fossa irrespective to teeth contact, It is the starting point of occlusion.

Centric occlusion : teeth to teeth relation ship it is the maximum occlusal contact or intercuspation irrespective of condylar position. Maxillary and mandibular teeth should contact in harmonious manner that allows optimum function, minimum trauma to the supporting structure and an even distribution of load through the dentition.

Ideal requirements of bite registration material The materials should offer limited resistance before setting to avoid displacing the teeth or mandible during closure, whereas after setting, it should be rigid or resilient, with minimal dimensional change. • It should be easy to manipulate with no adverse effects on the tissues involved in the recording procedures. • It should accurately record the incisal and occlusal surfaces of teeth. • A very important feature - it should be verifiable.

Methods of inter-occlusal record: If enough teeth are present in both upper and lower arches to stabilize their relation ship. No bite registration is needed we can transfer the relation by hand articulation. 2. If the remaining teeth are insufficient to provide hand articulation of the cast we can use: -Pink base plate wax or alu-wax (wax reinforced with fiber)

1-Apiece of wax is placed on the maxillary teeth and ask the patient to close in centric relation then the wax is removed and placed in water for cooling.

How to record? Whatever the material used to record the relation between the upper and lower dental arches, we have to guide the mandible to the required relation (centric or eccentric). So, the patient is asked to close and guide him, put reference points, then we put the record material and register the relation. The most widely used material to record the relation is pink base blate wax. The procedure is by softening the wax at first, then we ask the patient to bite on it, keeping in mind that we have to guide the mandible to the reference points that we have marked to have the correct bite registration. Meanwhile, the patient is asked to mold the wax at the lingual area by his tongue, while we adapt the wax on the labial and buccal sides by our fingers. After complete setting of the wax, we remove it from the patient’s mouth, trim the excess wax, and attach it to the cast and transfer it to the articulator.

2-Registration paste: Zinc oxide eugenol quick set paste is mixed and applied on aplastic bite frame with fiber glass to support bite registration paste. It’s a common method of taking a bite it may be used unior bilaterally it has the advantage of producing accurate details and being very stable when set.

Dowson's technique: Dowson's in 1974 suggest to place the dental chair in reclined position and the patient's head fixed by the dentist standing behind the patient with both thumbs on the chin and the fingers resting on the inferior border of the mandible. Then by gentle downward pressure by thumbs and upward pressure on figure the patient's mandible will bring into centric and let the patient bite on the registration material.

Procedure: 1. Select the frame. 2. Mixed the registration paste and apply it on both sides of fiber glass. 3. Place the frame with past over the prepared teeth without interference with patient closure. 4. Ask the patient to close using a dowsons technique and check the key point of occlusion. 5. After setting trim the paste to a depth leaving only the tip of the cusp both prepared and unprepared side, so that the bite material will not interferes with complete seating of the cast into the bite taken. 6. Put the bite on its placed on one cast bring the other cast on the proper place and check the key point of occlusion. Mount both casts on articulator.

3- Occlusal rims: - When insufficient number of the teeth are present to stabilize the cast. A bite rim must be made using a base plate wax to replace the remaining teeth.( this rim is necessary when restoring anterior teeth and the posterior teeth are missing leaving unstable opposing cast).

Bite rim: The bite rim is used in the following cases: 1. Free end saddle. 2. When we need to restore the anterior teeth. 3. When we don’t have enough teeth to obtain the centric relation.

Glass bite material this material is introduced between the dental arches with the special cannula can be applied ideally between the dental arches much faster and more easily than other materials. Its staible and transparent . Luxabite rigid bite registration advantages: 1- Highly accurate to the models 2- Can be used with or without bite registration trays 3- No interference with closure of teeth 4- Fast setting and easy to trim 5- Resist normal temporary variations (better than wax) 6- No compression on mounting