Dental Tribune United Kingdom Edition

About the author Dr Peter Bausch Dr. Jean Bausch GmbH & Co. KG Oskar-Schindler-Str. 4 50769 Cologne Germany pb@bauschdental.de ‘In order to recon- struct physiological occlusion, correct visual identification of contact points is essential’ Centric relation is the po- sition of the mandible relative to the maxilla, with the intra- articular disc in place, when the heads of the mandibular condyles are against the most superior part of the distal-fac- ing incline of the glenoid fossa (i.e. the mandibular condyles are in their most superior and anterior position). For balanced occlusion in a static position, the patient should have enough ABC con- tacts on each quadrant in the intercuspal position. In this position, the teeth of the op- posing jaws achieve complete intercuspation and are in maximum contact with each other. The physiological influence of interfering initial contacts For most of the patients, their habitual position of the man- dible in maximum occlusion is the preferred position for occlusal restoration. However, even a tiny interfering pre- maturity contact of only 20 μ can trigger a compensatory reaction, placing the mandi- ble into a new physiological position. This is a natural re- action of our biological system to avoid higher forces focused only on one area. For example, if you are eat- ing something and you chew on a little grain of sand, you automatically shift your man- dible to a different position to protect your teeth. A perma- nent “grain of sand” (occlusal interference) can trigger an overload of the biological sys- tem, in which case the patient will have reached his or her maximum capacity for com- pensation. Pain symptoms can then become chronic. Occlusal restoration In order to reconstruct physi- ological occlusion, correct visual identification of contact points is essential. Occlusion checking materials (articulat- ing papers) with the effect of progressive colour transfer are helpful in identifying occlusal forces in intercuspal habitual position. Areas with higher force loads can be identified as darker-shaded markings with higher contrast. These markings likely indicate the initial contacts. Areas with less intense colour markings indicate contacts with lower occlusal forces or areas with no contact. Upon close exami- nation, these markings look like a donut. The centre of the contact point has a light- er shade. The more intense- coloured edge of the contact point is not part of the contact. Just the lighter-coloured cen- tre is the real contact area. For occlusal equilibration, only these areas should be ad- justed. For a balanced occlu- sion, the patient should have enough ABC contacts on each quadrant. Occlusal corrections can be additive or subtractive. If modification of the occlusal relationship in patients who have been grinding their teeth over a long period is needed, this may be challenging, as they would already have lost a significant part of their hard tooth tissue. A splint is indi- cated for treating such pa- tients (additive occlusion). Conclusion The reconstruction of physi- ological occlusion is essential for the complex functioning of the entire stomatognathic sys- tem. There are various con- cepts of occlusion. For record- ing and analysing the complex movement of the mandible, a wide range of electronic de- vices are available. Beside all these tools, a basic understanding of the biomechanical design of an occlusal surface is essential. Today, we have a wide selec- tion of different occlusion indicators to visualise these biomechanical structures. Soft colour-impregnated occlu- sion checking papers, in com- bination with thin occlusion checking films, are optimised for visual checking of the oc- clusal relationship between the maxilla and mandible. DT March 11-17, 201320 United Kingdom EditionClinical page 19DTß